BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Structural basis of specific lysine transport by Pseudomonas aerug inosa permease LysP DTSTART;VALUE=DATE-TIME:20260327T114000Z DTEND;VALUE=DATE-TIME:20260327T120000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10350@events.saip.org.za DESCRIPTION:Speakers: Emmanuel Nji (BioStruct-Africa)\nUnder conditions o f extreme acidity\, the lysine-specific permease\, LysP\, not only mediate s the import of L-lysine it also interacts with the transcriptional regula tor\, CadC\, to activate expression of the cadAB operon. This operon encod es the lysine decarboxylase\, CadA\, which converts lysine to cadaverine w hile consuming a cytoplasmic proton\, and the antiporter\, CadB\, which ex ports protonated cadaverine in exchange for extracellular lysine. Together \, these processes contribute to cytoplasmic pH homeostasis and support ba cterial acid resistance - a mechanism essential for the survival of pathog enic bacteria in acidic host environments. Here\, we present the cryo-EM s tructure of LysP from Pseudomonas aeruginosa in an inward-occluded conform ation (3.2–5.3 Å resolution)\, bound to L-lysine and a nanobody. L-Ly sine is coordinated by hydrophobic contacts\, cation–π interactions\, a nd by hydrogen bonding mostly with polar uncharged residues. Reconstitutio n of LysP into proteoliposomes confirms specific L-lysine transport\, whic h is competitively inhibited by L-4-thialysine. These findings provide a s tructural framework for understanding selective lysine recognition and inh ibition\, with implications for antibacterial drug design.\n\nhttps://even ts.saip.org.za/event/272/contributions/10350/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10350/ END:VEVENT BEGIN:VEVENT SUMMARY:Review of Medical Physics in Africa DTSTART;VALUE=DATE-TIME:20260326T150000Z DTEND;VALUE=DATE-TIME:20260326T163000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10349@events.saip.org.za DESCRIPTION:Speakers: Stephen Inkoom (Radiation Protection Institute\, Gha na Atomic Energy Commission )\nThis talk is is actually this month's PHYSI CS MATTERS presentation of the American Physical Society (APS) Forum on In ternational Physics (FIP). \n\nThis talk has its [separate registration a nd Zoom link][1]..\n\n\n**Abstract:**\nMedical physics (MP) has been an in dispensable and strategic stakeholder in the delivery of healthcare in Afr ica\, with immense support to diagnostic radiology (DR)\, nuclear medicine (NM) and radiotherapy (RT).\n\nThere are eleven (11) countries that have MP academic programmes and seven (7) that have clinical training programme s in Africa\, by the use of a harmonized curriculum developed by the Inter national Atomic Energy Agency (IAEA)\, with additional support from the tr aining of medical physicists through the International Centre for Theoreti cal Physics (ICTP) in Trieste\, Italy\, where one hundred and twenty-four (124) ICTP medical physics graduates have been trained since 2014/15 to 20 23/24 for ten (10) cycles.\n\nThe Federation of African Medical Physicist Organisations (FAMPO) was established in 2009\, and the Federation’s act ivities are extended throughout Africa and the local Islands in the Region . FAMPO promotes MP Professional Practice\, Education and Training\, Resea rch and Development within Africa. FAMPO region has more than 1\,200 Medic al Physicists for a population of about 1.3 billion. About sixty percent ( 60%) of MPs are in radiotherapy (RT)\; 30% in Medical Imaging\; 10% in Res earch & Industry. With respect to Medical Physicist recognition in Africa\ , only six (6) of the fifty-four (54) African countries have legislative r ecognition for MPs.\n\nFor the future\, FAMPO would continue to strengthen collaboration with National Member Organizations and members\, advocate f or legislative recognition of medical physicists\, enhance education and t raining opportunities for medical physicists\, collaborate with key bodies and institutions such as the International Organisation for Medical Physi cs (IOMP)\, International Atomic Energy Agency (IAEA)\, American Associati on of Physicists in Medicine (AAPM)\, etc. to bridge the knowledge gap and equip medical physicists with the skills necessary to meet the growing de mands of the field.\n\nIt is expected that these initiatives and partnersh ips would promote medical physics profession within the region\, strengthe n research and innovation within the medical physics community in Africa\, enhance legislative recognition\, and expand and enhance FAMPO’s networ k and member engagement.\n\n\n-------------\n**Biography**:\nProf. Stephen Inkoom obtained his PhD degree in Medical Physics in 2014 from the Univer sity of Ghana. The PhD programme was a sandwich programme between the Univ ersity of Ghana and University of Crete\, Greece with support from the Int ernational Atomic Energy Agency (IAEA) and the Government of Ghana.\n\nPro f. Stephen Inkoom is currently a Deputy Director and Chief Research Scient ist at the Radiation Protection Institute of the Ghana Atomic Energy Commi ssion. He is also Associate Professor of Medical Physics\, School of Nucle ar and Allied Sciences\, University of Ghana. His work focuses on radiatio n protection\, medical physics\, and the safe application of nuclear and a ccelerator-based technologies in healthcare\, reserach and industry. He is actively involved in national and international initiatives supporting ca pacity building\, regulation\, and the development of medical physics in A frica\, working closely with organizations such as the IAEA and served as a Project Scientific Consultant for IAEA Project RAF9064- Improving the Ca pabilities of Member States for Radiation Protection of Member States\, In ternational Organization for Medical Physics (IOMP)\, Federation of Africa n Medical Physics Organizations (FAMPO) where He serves as the Secratray G eneral\, and others to strengthen education\, research\, and clinical prac tice of medical physics and radiation protection across the region. As Pro ject Coordinator for the NORPART Project\, 20+ Masters and PhD Students be nefitted from Students Exchange Programme for students from Universities i n Ghana for an Exchange Stay (2018-2023) at the Norwegian University of Sc ience and Technology (NTNU)\, Trondheim\, Norway in Medical Physics and Ra diation Protection Education. Additionally\, 500+ trainees benefited from Annual Summer Schools in Ghana (2016 – 2023) in Medical Physics and Radi ation Protection Education. He has mentored 50+ Medical Physics students f rom Africa\, and been playing a Leading role in Medical Physics education and training in Africa. Prof. Stephen Inkoom has 20 years of experience in radiation protection and medical physics practice\, providing leadership and mentorship in education and training\, research and professional devel opment both in Africa and globally.\n\n\n [1]: https://apsphysics.zoom.us /webinar/register/WN_YuPbgNXfTyuYA0ePH2BZBA#/registration\n\nMore about PH YSICS MATTERS\, https://engage.aps.org/fip/resources/activities/physics-ma tters\n\nDiscover International Engagement page\, https://www.aps.org/abou t/international\n\nand\n Free possible APS membership (https://www.aps. org/membership/join/physicists-worldwide) \n Free student membership\n More activities available by joining FIP (https://engage.aps.org/fip/ho me)\n\nhttps://events.saip.org.za/event/272/contributions/10349/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10349/ END:VEVENT BEGIN:VEVENT SUMMARY:We are all different: Modeling key individual differences in physi ological systems DTSTART;VALUE=DATE-TIME:20260324T130500Z DTEND;VALUE=DATE-TIME:20260324T140500Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10334@events.saip.org.za DESCRIPTION:Speakers: Anita LAYTON (University of Waterloo)\nMathematical models of whole-body dynamics have advanced our understanding of human int egrative systems that regulate physiological processes such as metabolism\ , temperature\, and blood pressure. For most of these whole-body models\, baseline parameters describe a 35-year-old young adult man who weighs 70 k g. As such\, even among adults those models may not accurately represent h alf of the population (women)\, the older population\, and those who weigh significantly more than 70 kg. Indeed\, sex\, age\, and weight are known modulators of physiological function. To more accurately simulate a person who does not look like that "baseline person\," or to explain the mechani sms that yield the observed sex or age differences\, these factors should be incorporated into mathematical models of physiological systems. Another key modulator is the time of day\, because most physiological processes a re regulated by the circadian clocks. Thus\, ideally\, mathematical models of integrative physiological systems should be specific to either a man o r woman\, of a certain age and weight\, and a given time of day. A major g oal of our research program is to build models specific to different subpo pulations\, and conduct model simulations to unravel the functional impact s of individual differences.\n\nhttps://events.saip.org.za/event/272/contr ibutions/10334/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10334/ END:VEVENT BEGIN:VEVENT SUMMARY:Opening Plenary Remarks DTSTART;VALUE=DATE-TIME:20260324T130000Z DTEND;VALUE=DATE-TIME:20260324T130500Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10348@events.saip.org.za DESCRIPTION:https://events.saip.org.za/event/272/contributions/10348/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10348/ END:VEVENT BEGIN:VEVENT SUMMARY:Optimizing Photobiomodulation For Smooth Muscle Differentiation of Adipose-Derived Stem Cells Using Retinoic Acid and TGFβ in a Two-Dimensi onal Model DTSTART;VALUE=DATE-TIME:20260325T144000Z DTEND;VALUE=DATE-TIME:20260325T150000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10346@events.saip.org.za DESCRIPTION:Speakers: Christevie Mbuyu (Laser Research Centre)\nPhotobiomo dulation (PBM) refers to the application of low-level light at specific wa velengths delivered either continuously or in pulses with low and constant energy densities in order to modulate cellular activity. This study inves tigated the influence of PBM at 525 nm (green)\, 825 nm (near-infrared\; N IR) and a combination wavelength of both on adipose-derived stem cell (ADS C) using assays which assess cellular parameters such as proliferation\, v iability\, mitochondrial function\, extracellular matrix (ECM) production\ , migration and differentiation towards a smooth muscle cell (SMC) in th e presence of growth factors like retinoic acid (RA) and transforming grow th factor-β (TGF-β). ADSCs were exposed to fluences of 5 J/cm² and 10 J /cm² and assessed using metabolic (ATP)\, cytotoxicity (LDH)\, Giemsa for morphology\; mitochondrial membrane potential (MMP)\, collagen quantifica tion\, migration analysis and immunofluorescence staining of stemness and SMC associated markers. Morphological analysis demonstrated that ADSCs ini tially maintained a typical spindle-shaped morphology across all experime ntal groups. However\, fluence-dependent PBM effects became evident over t ime. Cultures exposed to 5 J/cm² maintained higher cell density and proli feration\, whereas 10 J/cm² groups showed sparser cultures and reduced gr owth\, consistent with the biphasic Arndt-Schulz response. ATP analysis su pported this trend with lower fluence groups demonstrating enhanced metabo lic activity by day 7\, while higher fluence groups showed reduced prolife ration. LDH levels remained low across all PBM-treated groups\, confirming the absence of cytotoxic effects. Mitochondrial analysis indicated a gene rally stable MMP values during early stages with increased levels at later stages suggesting mitochondrial adaptation during differentiation. Collag en production showed an early increase followed by a decline at later time points\, suggestive of ECM remodelling during cellular maturation. Migrat ion analysis revealed differences in cell motility between treatment group s\, indicating functional variations associated with PBM exposure. Immunof luorescence confirmed the progressive expression of smooth muscle associat ed markers including smooth muscle α actin\, desmin\, calponin and SMMHC during the experimental period. Collectively\, these findings demonstrate that PBM modulates ADSC behaviour in a fluence-dependent fashion and may s upport smooth muscle lineage development under inductive culture condition s further highlighting the potential role of PBM in regenerative medicine applications.\n\nhttps://events.saip.org.za/event/272/contributions/10346/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10346/ END:VEVENT BEGIN:VEVENT SUMMARY:Insights into the Structural Analysis of Caffeine–Oxalic Acid Co -crystals Using High-Resolution PXRD and Computational Refinement DTSTART;VALUE=DATE-TIME:20260327T101000Z DTEND;VALUE=DATE-TIME:20260327T103000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10347@events.saip.org.za DESCRIPTION:Speakers: Sihle Thabethe (University of Cape Town)\nCo-crystal lization is a powerful tool in crystal engineering\, enabling modification of material and drug properties. While single-crystal methods dominate\, many systems crystallize only as powders\, requiring alternative approache s. We synthesized the caffeine–oxalic acid cocrystal and applied high-re solution powder X-ray diffraction (PXRD) with computational analysis to as sess phase formation\, crystallinity\, and supramolecular organization. PX RD data were collected on a Bruker D2 diffractometer and analyzed using Di ffrac.EVA\, Topas\, EXPO2014\, and DASH\, with structural models derived f rom the Cambridge Structural Database. Thermal analysis (TGA/DSC) was perf ormed to evaluate hydration\, phase purity\, and decomposition.\nPXRD prof iles confirmed successful co-crystal formation\, distinct from starting ma terials. Thermal analysis indicated no hydration\, with decomposition begi nning at 200 °C. Indexing revealed a monoclinic P21/a system consistent with prior reports\, with lattice parameters: a = 18.97 Å\, b = 14.88 Å \, c = 3.27 Å\, β = 122.74°. Structure solution via simulated annealing achieved a valid fit (Profile χ² < 2)\, refined further by Rietveld met hods. Hydrogen bonding analysis revealed partial expected interactions\, t hough higher-resolution synchrotron data will be required for full elucida tion. This work demonstrates the integrated use of PXRD\, computational re finement\, and thermal analysis as a practical strategy for investigating co-crystals and inclusion complexes in early-stage solid-form screening.\n \nhttps://events.saip.org.za/event/272/contributions/10347/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10347/ END:VEVENT BEGIN:VEVENT SUMMARY:Regulation of actin-binding proteins mediated by lipid-protein int eractions DTSTART;VALUE=DATE-TIME:20260326T130500Z DTEND;VALUE=DATE-TIME:20260326T132500Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10345@events.saip.org.za DESCRIPTION:Speakers: Yosuke Senju ()\nThe actin cytoskeleton drives membr ane deformation during many cellular processes\, such as migration\, morph ogenesis\, and endocytosis. Phosphatidylinositol 4\,5-bisphosphate [PI(4\, 5)P2]\, one of the phosphoinositides\, regulates the activities of many ac tin-binding proteins (ABPs)\, including profilin\, cofilin\, Dia2\, N-WASP \, ezrin\, and moesin\; however\, the underlying molecular mechanisms rema in elusive. Here\, we applied a combination of biophysical assays and atom istic molecular dynamics simulations to uncover the molecular principles u nderlying ABP interactions with phosphoinositide-containing membranes. Our results reveal that these proteins show significant differences in membra ne interaction dynamics and in the ranges of phosphoinositide densities th ey can sense. Profilin and cofilin show transient\, low-affinity interacti ons with membranes\, whereas F-actin assembly factors Dia2 and N-WASP stay on membranes longer to perform their functions. Ezrin and moesin\, which link the actin cytoskeleton to the plasma membrane\, bind to membranes wit h high affinity and slow dissociation kinetics\, regulating PI(4\,5)P2 lat eral diffusion. Unlike profilin\, cofilin\, Dia2\, and N-WASP\, they do no t require a high ‘stimulus-responsive’ phosphoinositide density for me mbrane binding. Together\, these findings demonstrate that the membrane-in teraction mechanisms of ABPs have evolved to precisely fulfill their speci fic cellular functions in cytoskeletal dynamics.\n\nhttps://events.saip.or g.za/event/272/contributions/10345/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10345/ END:VEVENT BEGIN:VEVENT SUMMARY:Linker switch mutations between canonical Plasmodium falciparum Hs p70-1 and PfHsp70-z reveal the role of this motif in regulating the functi onal specialisation of the two chaperones DTSTART;VALUE=DATE-TIME:20260326T104000Z DTEND;VALUE=DATE-TIME:20260326T110000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10336@events.saip.org.za DESCRIPTION:Speakers: Addmore Shonhai (University of Venda)\nOf the five m alaria-causing species\, Plasmodium falciparum accounts for most malaria-r elated deaths. Central to the survival and infectivity of the parasite is rapid replication coupled to upregulated protein production. Thus\, the de velopment of this malaria parasite is supported by the role of several hea t shock proteins (Hsps)\, which facilitate protein folding. P. falciparum Hsp70-1 (PfHsp70-1) and PfHsp70-z are essential molecular chaperones (mole cules that assist proteins to fold correctly) that are cytosol-localized. PfHsp70-z belongs to the Hsp110 cluster of Hsp70-like proteins. Whereas P fHsp70-1 serves as a refolding chaperone\, PfHsp70-z is restricted to prev enting aggregation of proteins in the cell. The structural features underp inning the functional specialization of these chaperones remain elusive. P fHsp70-z possesses a unique linker segment. In the current study\, we expl ored the role of the linker in regulating the functional specialization of the two P. falciparum Hsp70s. Using recombinant forms of PfHsp70-1\, PfHs p70-z\, and E. coli Hsp70 (DnaK) as well as their linker switch mutant for ms\, we explored the effects of the linker mutations using circular dichro ism\, intrinsic and extrinsic fluorescence coupled to biochemical and in c ellulo analyses. Our findings demonstrate that the linker of PfHsp70-z mod ulates global conformation of the chaperone\, regulating several functions such as client protein binding\, chaperone\, and ATPase activities. In ad dition\, as opposed to the flexible linker of PfHsp70-1\, the PfHsp70-z li nker is rigid\, conferring notable conformational stability to this chaper one\, making it an effective holdase chaperone. Our findings highlight the role of the linker in regulating the functional specificity of Hsp70. We discuss the implications of our findings to the development of the malaria parasite at the blood stages of the parasite.\n\nhttps://events.saip.org. za/event/272/contributions/10336/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10336/ END:VEVENT BEGIN:VEVENT SUMMARY:Petrologic and Geochemical Constraints on the Evolution of Rocks i n Southwest Ugep\, Southeastern Nigeria DTSTART;VALUE=DATE-TIME:20260325T101000Z DTEND;VALUE=DATE-TIME:20260325T103000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10339@events.saip.org.za DESCRIPTION:Speakers: ADAEZE UGWU (University of Wyoming\, USA)\nUgep Sout hwest is an extension of the Nigerian Basement Complex. It consists of Pre cambrian crustal rocks that include a succession of deformed metamorphic r ocks and non-deformed sedimentary rocks that overlie the basement rocks. T he metamorphic rocks are intruded by granodiorites and pegmatites. Gneisse s display a sharp contact relationship with the schists\, occurring in ass ociation with quartzite as observed in Ikot Ekperem. Granodiorites contain enclaves of schistose xenoliths\, indicating that magmatic stoping was th e mode of emplacement during the Pan-African Orogeny (600 ± 50 Ma). Ugep Southwest has undergone various stages of deformation\, as evidenced by co mplex structures such as folding\, faulting\, fracturing\, lineation\, and foliation. The grade of metamorphism was progressive from lower greenschi st facies (phyllites and schists) in the west to middle amphibolite facies (gneisses) in the east. Petrological observation using Scanning Electron Microscope (SEM) reveals that the metamorphosed rocks are dominantly compo sed of plagioclase\, biotite\, chlorite\, and muscovite. Pegmatites have a higher concentration of quartz relative to their magma source. Geochemica l analysis using X-ray Fluorescence Spectrometer (XRF) reveals high conten ts of silica and alumina\, implying a crustal origin for the rocks. Barium concentration was higher\, suggesting contamination by crustal materials. The geochemistry of these rocks reveals that phyllite and schist are meta sediments of pelitic and greywacke composition\, while the gneiss is ortho gneiss. Granodiorite is calc-alkaline\, and the dolerite is tholeiitic. Th e plots in variation diagrams confirm these geochemical signatures.\n\nhtt ps://events.saip.org.za/event/272/contributions/10339/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10339/ END:VEVENT BEGIN:VEVENT SUMMARY:Spatial Distribution and Assessment of Background Ionizing Radiati on around Waste Dumpsites in Gombe Metropolis\, Nigeria DTSTART;VALUE=DATE-TIME:20260325T095000Z DTEND;VALUE=DATE-TIME:20260325T101000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10344@events.saip.org.za DESCRIPTION:Speakers: Muhammad Nuruddeen Abdulkareem (Department of Physic s\, Federal University of Kashere\, Gombe State. Nigeria )\nWaste dumpsite s are potential sources of environmental radiation\, yet baseline data for many urban centers in northeastern Nigeria remain sparse. This study asse ssed the background ionizing radiation levels at ten (10) selected waste d umpsites across different land-use categories in Gombe Metropolis\, Nigeri a. In situ measurements were conducted using a calibrated Medicom CRM-100 Digital Radiation Monitor at a height of 1.0 m above ground level\, with g eographic coordinates recorded via GPS. The results indicate that the outd oor absorbed dose rates (ADR) ranged from 10.0 ± 1.0 to 23.3 ± 2.3 nGy· h⁻¹\, with a mean of 16.7 ± 4.0 nGy·h⁻¹. A spatial variation of 13 3% was identified between the highest exposure site (Dukku Motor Park) and the lowest (Madaki Quarters)\, reflecting a correlation between commercia l land-use and elevated radiation levels. The estimated annual effective d ose rates (AEDR) varied from 0.018–0.041 mSv·y⁻¹\, while the excess lifetime cancer risk (ELCR) ranged from (0.70 ± 0.07) × 10⁻⁴ to (1.6 3 ± 0.16) × 10⁻⁴. The maximum ELCR value corresponds to approximatel y 16 additional cancer cases per 100\,000 persons\, which is significantly lower than the WHO global baseline cancer risk and the ICRP public exposu re limit of 1 mSv·y⁻¹. The study concluded that current waste disposal practices in the metropolis do not pose an immediate radiological health threat\; however\, routine monitoring is recommended to detect future devi ations in the radiological profile.\n\nhttps://events.saip.org.za/event/27 2/contributions/10344/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10344/ END:VEVENT BEGIN:VEVENT SUMMARY:Thermomechanical Mapping of DNA under Coupled Salt-Temperature Con trol with oxDNA2 Coarse-Grained Simulations DTSTART;VALUE=DATE-TIME:20260327T111000Z DTEND;VALUE=DATE-TIME:20260327T113000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10343@events.saip.org.za DESCRIPTION:Speakers: Isaiah Igwe (Federal University Dutsin-Ma)\nQuantify ing how temperature and ionic strength jointly determine the elastic prope rties of double-stranded DNA remains a central challenge in molecular biop hysics. Although individual temperature or salt dependent trends have been measured\, a unified\, mechanistic map across high-salt and elevated-temp erature regimes is still lacking. Here\, we use the oxDNA2 coarse-grained model to compute a 3×9 thermodynamic ionic grid spanning 300 –373 K and 0.5 – 1.5 M monovalent salt\, enabling controlled evaluation of elastic properties and structural observables under conditions where electrostati c screening is extremely strong. Simulations were performed on long 500-bp duplexes with full ensemble averaging over independent replicate trajecto ries at each condition. Across all salt concentrations\, DNA softens as te mperature increases\, but the degree of softening depends on ionic strengt h. At 0.5 M\, the bending persistence length drops from about 43 nm at 300 K to 32 nm at 373 K. At 1.5 M\, the decrease is far smaller (46 → 39 nm )\, showing that high salt reduces thermal sensitivity by roughly 40–50% . Torsional stiffness shows the same pattern (110 → 92 units at 0.5 M vs . 118 → 105 units at 1.5 M)\, as does twist–stretch coupling\, which c hanges by 0.7 units at low salt but only 0.4 units at high salt. Helical t wist decreases by roughly 1.1–1.3° per kbp per 10 K at 0.5 M\, with a v isibly weaker dependence at 1.5 M. While both bending and torsional rigidi ties soften with temperature\, torsional elasticity remains closer to harm onic behavior than bending\, with anharmonic deviations staying below ~10% even at the highest temperatures. Structural measures\, including base-pa ir occupancy and stacking energies\, show that the duplex remains intact u p to about 95 –100 °C\, with only limited end fraying. Beyond quantifyi ng these trends\, the present work introduces a unified thermodynamic inte rpretation of DNA elasticity. The simulations demonstrate that the weakeni ng of base-stacking interactions precedes significant hydrogen-bond disrup tion and acts as the primary microscopic driver of thermoelastic softening . This perspective provides a compact statistical-mechanical description o f DNA thermoelasticity and helps reconcile observations from coarse-graine d simulations\, atomistic molecular dynamics\, and single-molecule experim ents.\n\nhttps://events.saip.org.za/event/272/contributions/10343/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10343/ END:VEVENT BEGIN:VEVENT SUMMARY:Integrating Generative AI\, Computational Modeling\, and Physiolog ical Reasoning to Enhance Biological Sciences Education DTSTART;VALUE=DATE-TIME:20260327T105000Z DTEND;VALUE=DATE-TIME:20260327T111000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10338@events.saip.org.za DESCRIPTION:Speakers: Camellia Okpodu (University of Wyoming)\nPreparing f uture biophysicists requires approaches that connect foundational biologic al principles with modern computational tools. Our work introduces a Gener ative‑AI–enhanced framework for teaching bioinformatics\, designed to strengthen students’ computational reasoning\, data literacy\, and engag ement with cardiovascular‑related biological systems. This model emphasi zes ethical and effective integration of AI outputs into analysis and mode ling\, helping learners navigate emerging digital research environments. Building on this framework\, we developed a MATLAB‑based SpO₂ modeling exercise that guides students through finite‑difference modeling of oxy gen transport\, clinical decision‑making\, and the interpretation of phy siological data. By incorporating AI‑generated clinical scenarios into M ATLAB workflows\, students explore realistic diagnostic pathways and deepe n understanding of physiological mechanisms. Together\, these innovations create an accessible instructional pipeline—particularly valuable for st udents across the African diaspora—linking computational physiology\, ca rdiovascular innovation\, and AI‑supported reasoning. This combined appr oach broadens participation in biophysics education and offers scalable mo dels for strengthening quantitative and computational skills in the biolog ical sciences.\n\nhttps://events.saip.org.za/event/272/contributions/10338 / LOCATION: URL:https://events.saip.org.za/event/272/contributions/10338/ END:VEVENT BEGIN:VEVENT SUMMARY:From Sample to Structure: An Introduction to Cryo Electron Microsc opy and Single Particle Analysis DTSTART;VALUE=DATE-TIME:20260327T120000Z DTEND;VALUE=DATE-TIME:20260327T123000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10329@events.saip.org.za DESCRIPTION:Speakers: Rebecca Thompson (Thermo Fisher Scientific)\nUnderst anding biological function at the molecular level requires direct visualiz ation of macromolecular structure. For decades\, structural biology has re lied on approaches such as X ray crystallography and nuclear magnetic reso nance spectroscopy. Over the past decade\, cryo electron microscopy has ra pidly matured into a central method for protein structure determination\, expanding the scope of questions that can be addressed at high resolution. In 2025\, over 10\,000 structures were deposited into the electron micros copy data bank\, and in the next few years it is projected single particle cryoEM will become the predominant technique for protein structure determ ination. \nCryo electron microscopy enables structure determination of pro teins and macromolecular complexes in a near native\, vitrified state with out the need for crystallization. In particular\, single particle analysis has become a powerful and widely adopted method for high resolution struc ture determination of soluble proteins\, membrane proteins\, viral particl es\, and dynamic multicomponent assemblies. Advances in direct electron de tectors\, electron optics\, automation\, and computational image processin g now make near atomic resolution structure determination increasingly rou tine in many academic laboratories.\nThe impact of cryo EM extends across diverse areas of the life sciences. In virology and infectious disease res earch\, cryo EM has resolved the structures of viral surface proteins\, in tact virions\, and host pathogen complexes\, directly informing vaccine de sign and antiviral development. In therapeutic research\, from small molec ules to biologics and monoclonal antibodies\, cryo EM enables detailed vis ualization of ligand binding\, antigen antibody interactions\, and epitope mapping\, accelerating structure guided drug design. In plant biotechnolo gy and crop science\, structural insights into photosynthetic complexes\, stress response machinery\, and plant pathogen interactions are guiding st rategies to improve yield\, resilience\, and food security.\nAt the same t ime\, advances in in silico protein structure prediction\, including AI ba sed approaches such as AlphaFold\, have transformed computational modellin g. While these tools are powerful\, experimental structural biology remain s essential. Cryo EM provides direct structural validation\, captures conf ormational heterogeneity\, reveals ligand binding and complex formation\, and enables the study of assemblies and cellular environments that remain difficult to access computationally.\nThis presentation will introduce the fundamental principles of cryo EM and single particle analysis\, placing the method within the broader structural biology workflow. Key steps\, inc luding sample preparation\, vitrification\, data acquisition\, and image r econstruction\, will be outlined with emphasis on practical considerations . Examples from modern 200 kV cryo TEM platforms such as the Glacios micro scope will illustrate how recent technological developments support a wide range of research projects. \nThe talk will conclude by looking beyond is olated particles toward cryo electron tomography and in situ structural an alysis. These approaches enable visualization of molecular machines direct ly within cells\, bridging molecular and cellular scales and opening new o pportunities to study biology in its native context.\n\nhttps://events.sai p.org.za/event/272/contributions/10329/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10329/ END:VEVENT BEGIN:VEVENT SUMMARY:Multiscale local self-organization of the human metaphase mitotic spindle DTSTART;VALUE=DATE-TIME:20260327T130000Z DTEND;VALUE=DATE-TIME:20260327T133000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10335@events.saip.org.za DESCRIPTION:Speakers: Will Conway (New York Structural Biology Consortium) \nThe current model of mitotic spindle assembly proposes that microtubules nucleate at spindle poles and grow inward to capture chromosomes. However \, recent structural studies reveal that spindles are composed of short mi crotubules that do not span the full pole-to-chromosome distance. It remai ns unclear how short\, disconnected microtubules collectively generate and transmit the forces necessary to build a bipolar spindle. Using cryo-elec tron tomography to map microtubule polarity in intact human cells\, we fin d that spindle microtubules form locally antiparallel dense regions with a consistent 8 nm wall-to-wall spacing. This spacing is too narrow for most molecular motors to fit between adjacent microtubules\, ruling out direct motor crosslinking of the bundle interior. Instead\, spacing scales inver sely with local microtubule density\, consistent with density-driven steri c interactions\, analogous to liquid crystal ordering. Motor perturbations combined with centriole depletion\, which generated motor-active monopola r spindles\, further revealed that the kinesin-5 Eg5 motor establishes loc al antiparallel overlap independently of spindle bipolarity\, while a bala nce of Eg5 and dynein regulates microtubule density to maintain spindle ar chitecture. Together\, these findings challenge the pole-centric model and suggest a bottom-up\, self-organized model in which motor-microtubule int eractions within dense bundles generate forces that build bipolar spindles .\n\nhttps://events.saip.org.za/event/272/contributions/10335/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10335/ END:VEVENT BEGIN:VEVENT SUMMARY:Identifying Quantum-Relevant Microstates in the Nav1.7 Sodium Chan nel Pore Using Ensemble Molecular Dynamics Descriptors DTSTART;VALUE=DATE-TIME:20260326T132500Z DTEND;VALUE=DATE-TIME:20260326T134500Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10307@events.saip.org.za DESCRIPTION:Speakers: Chitaranjan Mahapatra (Korea Advanced Institute of S cience & Technology\, South Korea)\nVoltage-gated sodium channels are cent ral to neuronal excitability and are major therapeutic targets\, yet their functional behavior emerges from highly heterogeneous and dynamically flu ctuating pore microenvironments that are difficult to characterize using s tatic structural models alone. In particular\, local ion hydration and coo rdination motifs within the pore can vary substantially over time\, potent ially modulating energetic sensitivity in ways that are not fully captured by classical force fields. Here\, we present a reproducible classical-to- quantum workflow for identifying and prioritizing quantum-relevant microst ates in the pore of the human Nav1.7 sodium channel. Using an explicit-sol vent molecular dynamics simulation\, we extract time-resolved descriptors of the local pore microenvironment\, including sodium ion hydration number \, oxygen coordination\, and spatial occupancy within a protein-centered p ore region. These descriptors are used to classify distinct microenvironme ntal microstates and to construct a qualitative joint-occupancy landscape that highlights recurrent hydration–coordination motifs without invoking fully converged free-energy surfaces. We demonstrate how this ensemble-ba sed microstate analysis can be used to select representative structural cl usters for subsequent quantum mechanical treatment\, thereby reducing the dimensionality and computational cost of high-level electronic structure c alculations such as density functional theory or variational quantum eigen solver (VQE) approaches. Conceptual quantum sensitivity illustrations are included to clarify how different hydration microstates may lead to diverg ent electronic energetics\, motivating targeted quantum refinement. Rather than providing definitive thermodynamic or conductive predictions\, this work establishes a practical and extensible framework for bridging long-ti mescale classical simulations with focused quantum calculations in ion cha nnels. The proposed methodology is broadly applicable to other membrane pr oteins where transient microenvironmental heterogeneity is expected to pla y a functional role.\n\nhttps://events.saip.org.za/event/272/contributions /10307/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10307/ END:VEVENT BEGIN:VEVENT SUMMARY:Biophysical Modeling of Real-Time Cellular Mechanical Responses to Ionizing Radiation for Predicting Radiotherapy Outcomes DTSTART;VALUE=DATE-TIME:20260325T122000Z DTEND;VALUE=DATE-TIME:20260325T124000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10342@events.saip.org.za DESCRIPTION:Speakers: Nyasha Njanji (University of Zimbabwe)\nMedical biop hysics continues to expand the understanding of how physical forces and ra diation interact with biological systems. While traditional radiobiology f ocuses mainly on DNA damage and biochemical pathways\, the mechanical resp onses of cells to ionizing radiation remain relatively unexplored. This st udy proposes a novel approach that investigates how radiation exposure alt ers the mechanical properties of cancer cells\, including cellular stiffne ss\, membrane tension\, and cytoskeletal structure.\nThe research integrat es radiation physics with cellular biomechanics to analyze the real-time m echanical responses of cells during irradiation. Advanced biophysical tech niques such as atomic force microscopy and high-resolution optical imaging are proposed to measure changes in cell elasticity and deformation after controlled radiation exposure. These measurements are combined with comput ational modelling to establish correlations between radiation dose deposit ion and mechanical alterations within the cell.\nPreliminary theoretical m odels suggest that radiation-induced stress can cause rapid cytoskeletal r eorganization\, leading to measurable changes in cellular mechanical prope rties before conventional biological markers become detectable. Identifyin g these mechanical signatures may provide early indicators of cellular rad iation damage and radio-sensitivity.\nThe findings of this study could int roduce a new dimension in radiotherapy research by linking radiation–mat ter interactions with cellular biomechanics. Such insights may contribute to the development of rapid biophysical biomarkers for predicting treatmen t response and optimizing personalized radiotherapy strategies. Ultimately \, this interdisciplinary approach may enhance both the precision and effe ctiveness of modern cancer treatment.\n\nKeywords: Medical biophysics\, ce llular biomechanics\, ionizing radiation\, radiotherapy response\, cytoske leton mechanics\, predictive modeling\n\nhttps://events.saip.org.za/event/ 272/contributions/10342/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10342/ END:VEVENT BEGIN:VEVENT SUMMARY:Advances in MRI techniques for early detection and characterizatio n of brain tumors: A medical physics and biophysical perspective DTSTART;VALUE=DATE-TIME:20260325T120000Z DTEND;VALUE=DATE-TIME:20260325T122000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10341@events.saip.org.za DESCRIPTION:Speakers: Nyasha Njanji (University of Zimbabwe)\nEarly detect ion of brain tumors is essential for improving clinical outcomes and guidi ng effective therapeutic interventions. Magnetic Resonance Imaging (MRI) p lays a central role in neuro-oncology due to its non-invasive nature and s uperior soft-tissue contrast. Recent developments in MRI technology\, driv en by advances in medical physics and biophysical modeling\, have signific antly improved the sensitivity and specificity of brain tumor detection an d characterization. This study reviews key advanced MRI techniques\, inclu ding diffusion-weighted imaging (DWI)\, perfusion-weighted imaging (PWI)\, and functional MRI (fMRI) and their contributions to understanding tumor physiology and microstructure. Diffusion-weighted imaging quantifies the m icroscopic motion of water molecules\, providing biophysical information a bout cellular density and tissue architecture that helps distinguish tumor tissue from normal brain parenchyma. Perfusion-weighted imaging evaluates tumor vascularity and hemodynamic parameters\, offering insights into ang iogenesis and tumor grading. Functional MRI utilizes blood-oxygen-level-de pendent (BOLD) signal changes to map neural activity\, supporting the pres ervation of critical functional regions during neurosurgical planning. Fro m a medical physics perspective\, advancements in MRI acquisition protocol s\, signal modeling\, and quantitative imaging biomarkers have improved im age quality\, diagnostic reliability\, and reproducibility. The integratio n of these advanced MRI methods provides a comprehensive framework for ear ly tumor detection\, improved treatment planning\, and monitoring of thera peutic response. Continued progress in MRI physics and biophysical analysi s is expected to further enhance the role of imaging in precision neuro-on cology.\nKeywords: Medical Physics\, biophysics\, magnetic resonance imagi ng\, brain tumors\, diffusion-weighted imaging\, perfusion MRI\, functiona l MRI.\n\nhttps://events.saip.org.za/event/272/contributions/10341/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10341/ END:VEVENT BEGIN:VEVENT SUMMARY:Evaluation of Multifunctional Spinel and Hexaferrite Nanostructure s for Magnetic Hyperthermia and Advanced Tumor Therapy DTSTART;VALUE=DATE-TIME:20260325T114000Z DTEND;VALUE=DATE-TIME:20260325T120000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10337@events.saip.org.za DESCRIPTION:Speakers: Diaa EL-Rahman Rayan (Central Metallurgical Research & Development Institute (CMRDI))\, Mahmoud Ismail (Biophysics Branch an d Physics Department\, Faculty of Science\, Al-Azhar University\, Nasr Cit y\, Cairo\, Egypt)\nIn the present study\, a series of magnetic nanopartic les (MNPs) belonging to the spinel ferrite family (XFe2O4 where X = Mg\, C u\, Co\, Mn) and hexaferrite structures (Ba2Co2Fe12O22 and BaFe12O19) were synthesized using sol-gel and modified co-precipitation methods. The rese arch aims to optimize the structural and physical properties for localized cancer treatment via magnetic hyperthermia. The structural and morphologi cal characteristics were investigated using X-ray diffraction (XRD) and el ectron microscopy (FE-SEM/TEM)\, confirming the formation of pure crystall ine phases with tailored nanostructures. The optical properties were inves tigated using UV-visible spectroscopy\, revealing a significant dependence of the energy bandgap on the chemical composition and ion substitution. T he calculated bandgap values\, along with the magnetic parameters obtained from VSM\, were correlated to the induction heating performance. Under an alternating magnetic field (150–300 kHz)\, the specific absorption rate (SAR) values reached up to 350 W/g\, particularly in Mn-substituted coppe r ferrites.\nFurthermore\, the results indicate that the prepared MNPs\, e specially the optimized barium hexaferrite (Ba2Co2Fe12O22)\, exhibit a hig h potential for inhibiting tumor cell growth when activated by an external magnetic field. These findings highlight the potential of these optimized ferrites as high-performance agents for magnetic hyperthermia and multi-f unctional biomedical platforms\, offering a promising approach for non-inv asive thermal therapy.\nKeywords:\nMagnetic Hyperthermia\; Spinel Ferrites \; Hexaferrites\; substitution\; Optical Properties\; Bandgap\; Specific A bsorption Rate (SAR)\; Tumor Treatment.\n\nhttps://events.saip.org.za/even t/272/contributions/10337/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10337/ END:VEVENT BEGIN:VEVENT SUMMARY:Biogenic Silver Nanoparticles for Visible-Light Activated Breast C ancer Photodynamic Therapy DTSTART;VALUE=DATE-TIME:20260325T112000Z DTEND;VALUE=DATE-TIME:20260325T114000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10317@events.saip.org.za DESCRIPTION:Speakers: Isaac Baidoo (University of Johannesburg)\nSilver na noparticles (AgNPs) offer potent oncological potential via tunable SPR\, y et conventional toxicity remains a challenge. This study evaluates biogeni c synthesis and photoactivation as safer\, targeted alternatives for MCF-7 and MDA-MB-231 breast cancer cells. Specifically\, plant-mediated (biogen ic) and chemically synthesized AgNPs were evaluated as wavelength-activate d nanotherapeutics under matched surface plasmon resonance excitation cond itions. Biogenic AgNPs exhibited an SPR maximum at ~466 nm\, whereas chemi cally synthesized AgNPs displayed a peak at ~401 nm. Upon irradiation at 4 70 nm (biogenic) and 405 nm (chemical) with a fluence of 5 J/cm²\, distin ct photophysical and biological responses were observed.\nChemically synth esized AgNPs demonstrated modest photothermal conversion (ΔT ≈ 2.8 °C) \, while biogenic AgNPs showed negligible thermal elevation (<1 °C)\, ind icating minimal reliance on hyperthermic mechanisms. However\, biogenic Ag NPs generated substantially higher photoinduced reactive oxygen species (R OS)\, producing approximately threefold greater total ROS relative to chem ically synthesized counterparts under matched irradiation conditions. This enhanced photo-oxidative activity translated into significant reductions in cell viability. In MCF-7 cells\, photoactivation of biogenic AgNPs redu ced the IC50 to <2 µg/mL\, compared with 2.89 ± 0.20 µg/mL under dark c onditions. In MDA-MB-231 cells\, irradiation lowered the IC50 from 11.26 ± 0.04 µg/mL (dark) to 4.79 ± 0.05 µg/ml. Flow cytometric analysis con firmed apoptosis as the predominant mechanism of cell death\, with late ap optotic populations approaching ~40% following photoactivation.\nThese res ults indicate that biogenic AgNPs induce ROS-mediated phototoxicity at low er doses\, achieving effective cytotoxicity under visible-light activation without significant thermal effects\, supporting their translational pote ntial in cancer treatment.\n\nhttps://events.saip.org.za/event/272/contrib utions/10317/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10317/ END:VEVENT BEGIN:VEVENT SUMMARY:A Bioformulated Curcumin–Silver Nanoconjugate for Potent Photody namic Management of Resistant Lung Cancer DTSTART;VALUE=DATE-TIME:20260325T110000Z DTEND;VALUE=DATE-TIME:20260325T112000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10315@events.saip.org.za DESCRIPTION:Speakers: Glory Kah (University of Johannesburg)\nGlory Kah an d Heidi Abrahmse* \n\nLaser Research Centre\, Faculty of Health Sciences\, University of Johannesburg\, Doornfontein Campus. Post Office Box 17011\, Johannesburg 2028\, South Africa\n\n*Correspondence: Heidi Abrahamse. Ema il: habrahamse@uj.ac.za\n\nAbstract. Lung cancer remains a leading cause o f cancer-related mortality worldwide\, largely due to therapeutic resistan ce mediated by lung cancer stem cells (LCSCs). This study aimed to develop and evaluate a bioformulated curcumin–silver nanoparticle conjugate (Cu m-PEG-BpAgNPs) for enhanced photodynamic therapy (PDT) targeting both lung cancer cells (A549) and their stem cell subpopulations. Silver nanopartic les were synthesized using Bidens pilosa extract and conjugated with curcu min to form the nanoconjugate\, which was subsequently characterized. LCSC s expressing CD133⁺ and CD44⁺ markers were isolated via immunomagnetic bead sorting and confirmed by immunofluorescence. Cellular uptake and sub cellular localization were assessed using fluorescence microscopy. Cytotox icity following dark and 470 nm laser irradiation (5 J/cm²) was evaluated using MTT\, LDH\, and ATP assays\, while reactive oxygen species (ROS) ge neration\, mitochondrial membrane potential disruption\, apoptosis–necro sis profiling\, and expression of apoptosis-related proteins (p53\, caspas e-3\, and Bcl-2) were analyzed using DCFH-DA\, JC-10\, Annexin V-FITC/PI\, and ELISA assays\, respectively. Cum-PEG-BpAgNPs-mediated PDT demonstrate d significantly greater cytotoxicity compared to free curcumin\, with lowe r IC₅₀ values in both A549 cells (4.01 µg/mL) and LCSCs (2.37 µg/mL) . Enhanced intracellular uptake and broad organelle co-localization were o bserved for the nanoconjugate. Treatment induced elevated ROS production\, mitochondrial dysfunction\, and predominantly apoptotic cell death\, char acterized by upregulation of p53 and caspase-3 and downregulation of Bcl-2 . In conclusion\, the Cum-PEG-BpAgNPs nanoconjugate significantly improves PDT efficacy against lung cancer cells and resistant LCSCs by promoting R OS-mediated mitochondrial apoptosis\, highlighting its potential as a ther apeutic strategy for resistant lung cancer.\n\nhttps://events.saip.org.za/ event/272/contributions/10315/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10315/ END:VEVENT BEGIN:VEVENT SUMMARY:Phototoxicity of Pheophorbide-a in Caco-2 colorectal cancer cells examined through cellular responses and morphological characterisation DTSTART;VALUE=DATE-TIME:20260325T092000Z DTEND;VALUE=DATE-TIME:20260325T094000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10318@events.saip.org.za DESCRIPTION:Speakers: Fermin Broni (University of Johannesburg)\nAbstract: Photodynamic therapy (PDT) has increasingly been recognised as a promisin g biomedical strategy for the management of diverse cancers\, offering spa tial and temporal selectivity compared with conventional chemotherapeutic approaches. However\, its therapeutic success is critically dependent on t he phototoxic potential of the photosensitiser (Ps) employed and its abili ty to localise within key cellular compartments and trigger downstream dea th pathways. In this study\, we investigated the phototoxicity of Pheophor bide‑a (PPBa)\, a chlorophyll‑derived Ps\, in Caco‑2 colorectal canc er (CRC) cells under rigorously controlled light and dark conditions to de monstrate its mechanistic effects. Cell viability was assessed using compl ementary assays that revealed pronounced light‑dependent cytotoxicity\, whereas minimal toxicity was observed in the absence of irradiation\, emph asising the selectivity of PPBa‑mediated PDT. Subcellular localisation e xperiments demonstrated preferential accumulation of PPBa within mitochond ria\, a finding of relevance given the central role of mitochondrial integ rity in regulating apoptosis. This localisation correlated strongly with a poptotic signatures\, including ATP depletion\, nuclear condensation\, and programmed cell death pathway activation. Morphological analyses further confirmed phototoxic damage\, revealing characteristic features such as ce ll shrinkage\, membrane blebbing\, and chromatin condensation. Together wi th the functional viability data\, these structural alterations highlight the potential of PPBa to induce targeted and irreversible damage upon phot oactivation. Collectively\, our findings provide mechanistic insights into the cellular basis of PPBa‑mediated PDT in CRC cells. By integrating fu nctional viability assays\, localisation studies\, and morphological chara cterisation\, this work demonstrates the potential of PDT as a selective a nd effective therapeutic modality for CRC\, while also contributing to the broader understanding of Ps‑driven cancer therapy.\n\nhttps://events.sa ip.org.za/event/272/contributions/10318/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10318/ END:VEVENT BEGIN:VEVENT SUMMARY:Eco-Friendly Gold Nanoparticle-Hypericin Conjugates for Antibody-M ediated Breast Cancer Phototherapy DTSTART;VALUE=DATE-TIME:20260325T090000Z DTEND;VALUE=DATE-TIME:20260325T092000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10314@events.saip.org.za DESCRIPTION:Speakers: Mpho Mohlongo (University of Johannesburg)\nAbstract \nPhotodynamic therapy employing Hypericin has gained attention as a pote ntial alternative for breast cancer treatment\, yet its clinical utility r emains limited by poor solubility\, low selectivity\, and non-specific cel lular uptake. To address these challenges\, we developed a targeted nanopl atform integrating green-synthesized gold nanoparticles (AuNPs)\, Hyperici n\, and monoclonal antibody functionalisation for enhanced PDT in MCF-7 br east cancer cells.\nAuNPs were synthesized using an aqueous extract of Kni phophia porphyrantha\, providing a biocompatible and environmentally susta inable route. Hypericin was subsequently loaded onto the AuNP surface\, fo llowed by conjugation with a monoclonal antibody to yield a bionanoconjuga te with improved targeting capacity. Characterization via UV-Vis spectrosc opy\, dynamic light scattering\, and transmission electron microscopy conf irmed nanoparticle formation\, photosensitizer loading\, and successful an tibody attachment.\nTherapeutic performance was evaluated through cellular uptake imaging and cytotoxicity assays (MTT\, LDH\, ATP) alongside flow c ytometry following irradiation with a 594 nm diode laser. Free Hypericin r educed cell viability by ~50%\, whereas the antibody-conjugated Hypericin- AuNP nanoplatform decreased viability to below 30%. ATP levels dropped by 70% in targeted-nanoconjugate-treated cells compared to only 20% in free H ypericin-treated cells\, highlighting enhanced metabolic disruption.\nThes e findings demonstrate that antibody-mediated targeting significantly impr oves photodynamic efficacy\, establishing this green nanotechnology-derive d Hypericin-AuNP nanoplatform as a promising candidate for selective breas t cancer therapy.\n\nhttps://events.saip.org.za/event/272/contributions/10 314/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10314/ END:VEVENT BEGIN:VEVENT SUMMARY:Photodynamic Therapy against Drug-Resistant Cancer Cells DTSTART;VALUE=DATE-TIME:20260325T084000Z DTEND;VALUE=DATE-TIME:20260325T090000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10313@events.saip.org.za DESCRIPTION:Speakers: Paromita Sarbadhikary (University of Johannesburg)\n Photodynamic therapy (PDT) has emerged as a promising alternative or adjun ct modality for the treatment of breast cancer. PDT relies on the activati on of a photosensitizer (PS) by red or near-infrared light\, resulting in the generation of reactive oxygen species (ROS) that induce localized tumo r cell damage. Naturally derived tetrapyrrolic PSs have attracted consider able interest due to their favor-able photophysical characteristics. Pheop horbide-a\, a chlorophyll-derived tetrapyrrole\, demonstrates strong absor ption in the red region\, efficient singlet oxygen generation\, preferenti al tumor accumula-tion\, and minimal dark toxicity. Although Doxorubicin r emains one of the most widely used chemo-therapeutic agents for breast can cer treatment\, its prolonged administration is associated with the de-vel opment of multidrug resistance\, largely mediated by P-glycoprotein overex pression. PDT has shown potential efficacy in overcoming chemoresistant ph enotypes. In this study\, we comparatively evaluat-ed the in vitro phototh erapeutic efficacy of pheophorbide-a against wild-type MCF-7 breast cancer cells and Doxorubicin-resistant MCF-7 (MCF-7/DOX) cells using 660 nm ligh t irradiation.\n\nBoth cell subtypes were incubated with varying concentra tions of pheophorbide-a for 3 h under dark conditions\, followed by irradi ation with a 660 ± 20 nm LED source at a fluence of 1 J/cm² and a power density of 7.08 mW/cm². Cell viability was assessed 24 h post-irradiation using the MTT assay. The results demonstrated differential sensitivity be tween the two cell lines. Approximately 90% reduc-tion in cell viability w as observed in wild-type MCF-7 cells at 1.6 µM pheophorbide-a\, whereas a high-er concentration of 2.4 µM was required to induce a comparable leve l of cytotoxicity in MCF-7/DOX cells\, indicating moderate resistance in t he chemoresistant phenotype. Morphological observations further supported these findings. Wild-type MCF-7 cells exhibited significant cellular shrin kage\, membrane disruption\, and extensive cell death following the PDT. I n contrast\, MCF-7/DOX cells showed comparatively moderate cytotoxic effec ts\, with approximately 30–40% of cells retaining viable morphology at t he same treatment dose.\n\nOverall\, pheophorbide-a–mediated PDT demonst rated substantial phototoxic activity against both wild-type and Doxorubic in-resistant breast cancer cells\, although higher concentrations were nec essary to achieve similar efficacy in resistant cells. These findings sugg est that plant-derived chlorophyll-based tetrapyrrolic photosensitizers ho ld promise as effective PDT agents for targeting multidrug-resistant breas t carcinomas. Further mechanistic investigations are required to elucidate the underlying cell death signaling pathways and molecular mechanisms at protein\, gene\, and transcriptomic levels to enhance translational applic ability.\n\nhttps://events.saip.org.za/event/272/contributions/10313/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10313/ END:VEVENT BEGIN:VEVENT SUMMARY:Plant based photosensitizers: An in vitro study against cancer cel ls DTSTART;VALUE=DATE-TIME:20260325T082000Z DTEND;VALUE=DATE-TIME:20260325T084000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10311@events.saip.org.za DESCRIPTION:Speakers: Nosipho Fakudze (University of Johannesburg)\nBreast cancer remains a major global public health concern due to its continuous ly rising incidence rate across a variety of demographics. An estimated 2. 3 million new cases have made breast cancer higher in incidence rate than the commonly reported lung cancer. Furthermore\, women in developing count ries have higher mortality rates\, 15.3 compared to 11.3 per 100 000 but a much lower incidence rate (30.8 compared to 54.1 per 100\,000) associated with women in developed countries. The 5-year breast cancer survival rate in Sub-Saharan Africa is recorded at 40%. Research on cancer treatments h as shifted to natural products due to the numerous negative effects of con ventional breast cancer treatments\, such as chemotherapy\, hormone recept or therapy\, and surgery. Throughout history\, traditional medicine has su ccessfully treated a variety of illnesses with natural ingredients. The va riety of plants and their advantages\, main and secondary phytocompounds\, make them a cost-effective cancer treatment option with few adverse effec ts. Molecular oxygen\, photosensitizer (PS)\, and light are the three comp onents of photodynamic therapy (PDT)\, an alternative cancer therapy. Pheo phorbide-a and hypericin\, two naturally derived PS\, were utilized to stu dy the medicinal effects against breast cancer cells. Hypericin is extract ed from Hypericum perforatum\, while pheophorbide-a is a chlorophyll deriv ative. This study utilized cell viability assay\, flow cytometry\, and mor phological analysis to evaluate the efficacy of these PSs. MTT (3-[4\,5-di methylthiazol-2-yl]-2\,5 diphenyl tetrazolium bromide) assay showed signif icant cell death at 0.37 µM for pheophorbide-a and 0.07 µM for hypericin \, while morphological analysis showed altered cellular morphology\, also confirmed by initiation of apoptosis. Our study shows a promising cost-eff ective treatment modality for breast cancer due to the fact that it is pla nt derived.\n\nhttps://events.saip.org.za/event/272/contributions/10311/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10311/ END:VEVENT BEGIN:VEVENT SUMMARY:Green-Synthesized Silver Nanoparticle–Liposomal ZnPcS4 Nanoplatf orm for Enhanced Photodynamic Therapy in Breast Cancer DTSTART;VALUE=DATE-TIME:20260325T080000Z DTEND;VALUE=DATE-TIME:20260325T082000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10310@events.saip.org.za DESCRIPTION:Speakers: Alexander Chota (University of Johannesburg\, Laser Research Centre)\nBreast cancer remains a formidable challenge in oncology despite significant advancements in treatment modalities. Conventional th erapies such as surgery\, chemotherapy\, radiation therapy\, and hormonal therapy have been the mainstay in managing breast cancer for decades. Howe ver\, a subset of patient’s experiences treatment failure\, leading to d isease recurrence and progression. Therefore\, this study investigates the therapeutic potential of green-synthesized silver nanoparticles (AgNPs) u sing an African medicinal plant (Dicoma anomala methanol root extract) as a reducing agent for combating breast cancer. AgNPs were synthesized using the bottom-up approach and later modified with liposomes (Lip) loaded wit h photosensitizer (PS) zinc phthalocyanine tetra-sulfonate (Lip@ZnPcS4) us ing thin film hydration method. The successful formation and Lip modificat ion of AgNPs\, alongside ZnPcS4\, were confirmed through various analytica l techniques including UV–Vis spectroscopy\, Fourier-transform infrared spectroscopy (FT-IR)\, high-resolution transmission electron microscopy (H R-TEM)\, scanning electron microscopy (SEM) and energy dispersive X-ray sp ectroscopy (EDS). Following a 24 h treatment period\, MCF-7 cells were ass essed for viability using 3-[4\,5-dimethylthiazol-2-yl]-2\,5 diphenyl tetr azolium bromide (MTT viability assay)\, cell death analysis using mitochon drial membrane potential (MMP) (ΔΨm)\, Annexin V-fluorescein isothiocyan ate (FITC)-propidium iodide (PI) kit\, and caspase- 3\, 8 and 9 activities . The experiments were repeated four times (n = 4)\, and the results were analyzed using SPSS statistical software version 27\, with a confidence in terval set at 0.95. The synthesized nanoparticles and nanocomplex\, includ ing AgNPs\, AgNPs-Lip\, Lip@ZnPcS4\, and AgNPs-Lip@ZnPcS4\, exhibited nota ble cytotoxicity and therapeutic efficacy against MCF-7 breast cancer cell s. Notably\, the induction of apoptosis\, governed by the upregulation of apoptotic proteins i.e.\, caspase 8 and 9 activities. In addition\, caspas e 3 was not expressed by MCF-7 cells in both control and experimental grou ps. Given the challenging prognosis associated with breast cancer\, the fi ndings underscore the promise of liposomal nanoformulations in cancer phot odynamic therapy (PDT)\, thus warranting further exploration in clinical s ettings*emphasized text*\n\nhttps://events.saip.org.za/event/272/contribut ions/10310/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10310/ END:VEVENT BEGIN:VEVENT SUMMARY:Parameter study and optimization of real-time single-particle trac king DTSTART;VALUE=DATE-TIME:20260325T142000Z DTEND;VALUE=DATE-TIME:20260325T144000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10321@events.saip.org.za DESCRIPTION:Speakers: Salomon van Niekerk (University of Pretoria)\nThe re al-time tracking of single particles is a vastly under-developed experimen tal technique but it offers great potential in understanding molecular dyn amics. A suitable tracking system comprises three key components\, viz.\, a position sensor\, a control system\, and an output actuator. The positio n sensor enables accurate prediction of the particle location. For this co mponent\, various tracking methods often employ an estimator of which the scanning pattern is a crucial part. A laser beam is generally scanned in a fixed pattern whilst the photons emitted by the tracked particles are cap tured and the corresponding photon counts and position coordinates are use d to predict the particle location. This process is repeated until some fo rm of termination condition is met. The choice of fixed pattern plays a si gnificant role in the accuracy of the estimator and hence the tracking cap abilities of the set-up. In this presentation\, we will show how different patterns and detection strategies can be employed in conjunction with acc urate two-dimensional single-particle tracking (SPT) simulations of emitti ng and non-emitting particles to identify an optimal combination. Fluoresc ence and interferometric scattering (iSCAT) are simulated to represent emi tting and non-emitting particles respectively. The performance of each con figuration is evaluated using some statistical metrics (e.g.\, average tra cking error).\n\nhttps://events.saip.org.za/event/272/contributions/10321/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10321/ END:VEVENT BEGIN:VEVENT SUMMARY:The artificial optical microscope. DTSTART;VALUE=DATE-TIME:20260325T140000Z DTEND;VALUE=DATE-TIME:20260325T142000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10340@events.saip.org.za DESCRIPTION:Speakers: Alberto Diaspro (Department of Physics - University of Genoa)\nMultimodal optical microscopy has recently converged with artif icial intelligence (AI) to the computational prediction of fluorescence‑ based molecular\ncontrast from label‑free measurements. Fluorescence pla ys a crucial role in linking microscopy and spectroscopy at molecular leve l\, enabling image formation from the cellular to the molecular detail. A challenging development in this field is the coupling of fluorescence with label-free polarization and phase optical methods. We will discuss how t his convergence\, together with modern generative\nmodeling for in‑silic o labeling\, is turning the optical microscope into an intelligent Instrum ent that we name artificial microscope.\n\nhttps://events.saip.org.za/even t/272/contributions/10340/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10340/ END:VEVENT BEGIN:VEVENT SUMMARY:The efficacy of PAM fluorometry as a tool to quantify heat stress in wheat DTSTART;VALUE=DATE-TIME:20260325T130000Z DTEND;VALUE=DATE-TIME:20260325T132000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10320@events.saip.org.za DESCRIPTION:Speakers: Sarah Burnett (Univeristy of Pretoria)\nFluorescence (spontaneous emission) is a highly sensitive probe for a multitude of mol ecular processes during the light-dependent steps of photosynthesis in num erous organisms. In living organisms\, the fluorescence signal is dwarfed by reflection and scattering\; however\, the signal-to-noise ratio can be significantly enhanced by gating the fluorescence to sub-msshort excitati on pulses through a non-invasive technique known as pulse-amplitude-modula ted (PAM) fluorometry. Wheat is an economically important crop that is sus ceptible to heat stress and consequent yield reduction at temperatures abo ve 30°C. However\, the changes to molecular processes that cause the decr ease in yield have not been well reported. In this study\, PAM fluorometr y was used to investigate the effects of high temperatures on the energy t ransfer pathways during the light-dependent steps of photosynthesis. The q uantum efficiency of energy conversion from light to chemical energy was n ot significantly altered at 30°C but was reduced by 10.7% at 35°C. We sh ow that the biological changes due to the heat shock response to heat stre ss can be measured at a time resolution of 30 seconds. PAM fluorometry\, and thus fluorescence\, is able to provide information about the effects o f heat stress on electron transport during light-dependent photosynthesis. This opens many possible directions of study\, such as investigating the effects of different types of stress on photosynthesis or further modellin g the photosynthetic energy-transfer pathways under heat stress.\n\nhttps: //events.saip.org.za/event/272/contributions/10320/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10320/ END:VEVENT BEGIN:VEVENT SUMMARY:International Union for Pure and Applied Biophysics DTSTART;VALUE=DATE-TIME:20260326T140000Z DTEND;VALUE=DATE-TIME:20260326T141000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10333@events.saip.org.za DESCRIPTION:Speakers: Anthony Watts (University of Oxford)\nhttps://events .saip.org.za/event/272/contributions/10333/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10333/ END:VEVENT BEGIN:VEVENT SUMMARY:Structural insights into the DDX11 helicase DTSTART;VALUE=DATE-TIME:20260326T110000Z DTEND;VALUE=DATE-TIME:20260326T113000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10324@events.saip.org.za DESCRIPTION:Speakers: Silvia Onesti (N/A)\nHelicases are essential and ubi quitous enzymes\, playing a key role in a variety of processes in DNA and RNA metabolism. A subset of helicases play specialised and specific functi ons by resolving/remodelling a variety of atypical DNA structures\, such a s G-quadruplexes\, triplexes\, Holliday junctions\, as well as displacemen t loops (D-loops and R-loops): among those a major role is played by the F eS family. Helicases containing FeS-clusters are ubiquitous but their exac t mechanism of action is poorly understood\; no structural information is available for some medically-relevant members of the family\, like FANCJ\, DDX11 and RTEL1.The combination of the intrinsic conformational flexibili ty\, FeS cluster lability and size makes them challenging targets for stru ctural biology.\n\nDDX11 plays an important role in sister-chromatid cohes ion\, associates with the replisome and is involved in processing non-cano nical nucleic acid structures. We have expressed and purified the human pr otein with an intact FeS cluster and carried out an extensive biochemical characterization. We have collected Cryo-EM data for the protein alone and in complex with a DNA fork: the apo structure is being refined at 3.5 Å resolution and a preliminary 5 Å structure in complex with a DNA fork has been determined. We can clearly see the path of the DNA fork bound to the helicase including the double helix\, and the 5’ single strand across t he motor domains. Interestingly\, in same regions the structure differs si gnificantly from the AlphaFold model. \nThese structures provide an essent ial framework to better understand the role of these enzymes.\n\nhttps://e vents.saip.org.za/event/272/contributions/10324/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10324/ END:VEVENT BEGIN:VEVENT SUMMARY:Steroidal Pregnanes as 11β-HSD1 Modulators: Insights from Random Forest-Based QSAR and Atomistic Simulations DTSTART;VALUE=DATE-TIME:20260327T103000Z DTEND;VALUE=DATE-TIME:20260327T105000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10309@events.saip.org.za DESCRIPTION:Speakers: Oludare Ogunyemi (University of Ibadan)\nThe enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) is a validated therap eutic target for Type 2 diabetes mellitus due to its role in local regener ation of active glucocorticoids. Current inhibitors are often limited by t heir constrained chemical diversity\, moderate potency\, and off-target ef fects. The therapeutic potential of steroidal pregnanes in diabetes and me tabolic disorders is been widely reported\; however\, their molecular targ ets\, particularly in glucocorticoid signaling\, remain poorly understood. This study explored the interactions of a curated library of steroidal pr egnanes with 11β-HSD1 using integrated Machine Learning (ML)-based QSAR\, molecular docking\, 100 ns Molecular Dynamics (MD) simulations\, and MM-G BSA binding free energy calculations. Initial exploratory chemical space a nalysis of the IC50 bioactivity dataset revealed that hydrogen donors\, mo lecular weight\, and lipophilicity may contribute to the bioactivity of 11 β-HSD1 inhibitors. Evaluation of 42 ML algorithms based on performance me trics revealed Random Forest Regressor (RFR) as a top model for bioactivit y predictions. Molecular docking simulation of the top RFR-predicted comp ounds (pIC50 ≥ 6.0 and pKi ≥ 7.8) with the active site of 11β-HSD1 id entified three compounds (pregnane-3\, 20-diol disulphate (P1)\, 20-Piperi din-2-yl-5α-pregnan-3β\,20-diol (P2)\, and 12\,20-di-O-benzoyl-pregnane- 3β\,12β\,14β\,20-tetraol (P3)). While the reference carbenoxolone prima rily strongly involved peripheral polar contacts to stabilize its orientat ion\, the pregnane scaffolds demonstrated deeper insertion into the hydrop hobic catalytic cavity of 11β-HSD1\, resulting in enhanced shape compleme ntarity and van der Waals packing. The thermodynamic parameters computed f rom the MD simulation trajectories revealed both the structural stability and intrinsic conformational flexibility of the 11β-HSD1–pregnane compl exes. Moreover\, the lower MM-GBSA binding energies of P1 (-43.58 kcal/mol ) and P3 (-44.95 kcal/mol) as compared with the reference carbenoxolone (- 24.19 kcal/mol) indicate high binding affinity and validate the docking sc ores of the hits. Additionally\, the leads exhibited favorable physicochem ical and pharmacokinetic profiles. Overall\, our findings provide mechanis tic insights into ligand binding and highlight key structural features tha t may account for 11β-HSD1 modulation by steroidal pregnanes\, offering a framework for the rational design of pregnane-derived therapeutics.\n\nht tps://events.saip.org.za/event/272/contributions/10309/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10309/ END:VEVENT BEGIN:VEVENT SUMMARY:Structure-Based Discovery of KRAS Inhibitors DTSTART;VALUE=DATE-TIME:20260327T123000Z DTEND;VALUE=DATE-TIME:20260327T125000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10319@events.saip.org.za DESCRIPTION:Speakers: Amanuel Getahun Addis (Bahir Dar University)\n**Abst ract**\nKristen rat sarcoma (KRAS) is an oncogene responsible for almost 2 0% of all human cancers and over 90% of pancreatic ductal adenocarcinoma. To date\, only two covalent drugs are approved by the United States food and drug administration (FDA) for the treatment of KRAS G12C related canc ers. However\, their effectiveness is limited in cancers driven by non-G12 C KRAS mutations as they rely on covalent bonding to the mutant Cys12. On top of that\, the emergence of resistance to allele-specific inhibitors h as shifted substantial effort toward developing noncovalent KRAS inhibitor s. As a result\, several noncovalent inhibitors are in clinical trials\, yet none has been approved for market use\, underscoring the need for new inhibitors. In this study\, we reported small molecules that show a promi sing micromolar anti-proliferation activity against pancreatic cancer cell lines. The investigated compounds are mainly amine-containing heterocycle s with scaffolds that are distinct from those found in existing drugs or l ead molecules.The molecules were identified through a structure-based drug design campaign on a physicochemically tailored 3D ligand library against switch II pocket of KRAS mutants. Based on their micromolar activity\, ex tensive interactions in predicted binding modes\, and analyses of structur al and physicochemical features\, we propose that these active hits can se rve as a starting point for the future characterization and optimization o f pan-KRAS inhibitors with broad efficacy. Moreover\, our work demonstrate s the proof of concept for using virtual screening in noncovalent drug dis covery to benefit from abundant 3D structures of drug-like molecules and t he growing database of experimental protein structures\, especially when c omputational resources are limited.\n\n**Keywords**: KRAS drug discovery\, virtual screening\, molecular docking\, cell growth assay\n\n* *Correspon dence to*: amanuel.getahun@bdu.edu.et\n\nhttps://events.saip.org.za/event/ 272/contributions/10319/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10319/ END:VEVENT BEGIN:VEVENT SUMMARY:Production of Leishmania spp. ∆24-sterol methyltransferases for the development of antiparasitic therapies DTSTART;VALUE=DATE-TIME:20260326T124500Z DTEND;VALUE=DATE-TIME:20260326T130500Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10325@events.saip.org.za DESCRIPTION:Speakers: Bernadette Belter ()\nParasitic diseases\, such as l eishmaniasis\, pose a growing global health threat\, particularly in regio ns with high HIV/AIDS prevalence [1]. The limited efficacy and growing res istance to current treatments necessitate the discovery of novel therapeut ic targets. ∆24-sterolmethyltransferase (SMT) is an attractive target as an essential enzyme in the ergosterol biosynthetic pathway of protozoa an d has no mammalian homologue [2]. SMT catalyses the transfer of a methyl g roup from S-adenosyl-methionine to the C24 position of zymosterol or lanos terol [3]. Structural characterisation of SMTs via X-ray crystallography i s crucial for structure-based drug discovery approaches. This study aims t o produce and structurally characterise SMTs from *Leishmania* *donovani* and *Leishmania major* to identify lead compounds for antiparasitic therap ies.\nThe *ERG6* genes\, encoding SMT\, from *L. donovani* and *L. major* were expressed in *E. coli*\, but resulted in insoluble protein. We then f used ERG6 to genes encoding mCherry or SUMO and successfully expressed the fusions as soluble proteins. The SMTs were cleaved from the fusion partne rs and purified using column chromatography methods. Furthermore\, the p urified SMTs have been shown to methylate lanosterol using GC-MS. Biotrans formation optimisation is underway to improve conversion yields.\nCrystall isation trials using the vapour-diffusion sitting-drop method are currentl y ongoing. Future work includes collecting X-ray diffraction data of the S MT crystals to solve their three-dimensional structures. The structural in formation\, as well as a robust crystal system\, is a prerequisite for X-r ay crystallographic fragment screening\, which will be used to map SMT bin ding pockets for inhibitor design. \nReferences\n[1] Dangarembizi\, R.\, W asserman\, S.\, Hoving\, J. C.\, et al. Parasite Immunology\, (2023) e1295 3. \n[2] Sakyi\, P. O.\, Kwofie\, S. K.\, Tuekpe\, J. K.\, et al. Pharmace uticals\, (2023) 16(3)\, 330.\n[3] Nes\, W.D.\, Chaudhuri\, M.\, Leaver\, D.J. Biomolecules\, (2024) 14:249.\n\nhttps://events.saip.org.za/event/272 /contributions/10325/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10325/ END:VEVENT BEGIN:VEVENT SUMMARY:The importance of water in biology - an example of receptor functi on and implications for optogenetics DTSTART;VALUE=DATE-TIME:20260326T120000Z DTEND;VALUE=DATE-TIME:20260326T124000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10331@events.saip.org.za DESCRIPTION:Speakers: Anthony Watts (University of Oxford)\nWater\, in its many states\, has a pivotal role in biology. But resolving it at the mole cular level has been a challenge. Here\, we resolve and describe how water determines the way in which an external stimulus\, light in this example\ , intimately controls how the stimulus is conformational changes in membra ne receptors in response to a stimulus\, and capturing their functionally relevant dynamics\, is very challenging. Over the years we have addressed this challenge using a range of spectroscopic approaches [1\,2\,3] on func tionally competent photoreceptors\, often in their natural membranes [4] o r Lipodisqs™ [5\,6]. More recently\, we have complemented this work with functional studies\, mass spec characterization [7] and very high resolut ion (1.07 Å) crystallography [8\,9\,10]\, as well as photo-induced x-ray\ , free electron laser studies (XFELS)\, without the use of detergents and including natural lipids. This high-resolution information reveals waters and their importance in both receptor activation-desensitization and QM(SC C-DFTB)/MM MD trajectories give information about the activation process. The system studied is achearhodopsin-3 (AR3)\, a photoreceptor utilized wi dely in optogenetics despite the lack of structures until now. We suggest that the different arrangement of internal water networks in AR3 is respon sible for the faster photocycle kinetics compared to homologs – AR3 is ~ 10x more efficient than bacteriorhodopsin at current generation. These ins ights may well have generic implications for other receptors.\n\n(1). Higm an et al.\, (2011) Angew. Chemie 50(36):8432\n(2). Dijkman et al.\, (2018) Nature Comms. 9:1710\n(3). Dijkman et al.\, (2020) Science Advances\, 6:3 3\n(4). Lavington & Watts (2020) Biophys. Rev. 12:1287\n(5). Juarez et al. \, (2019) Chem. Phys. Lipids 221:167\n(6). Sawczyc et al (2023) Eur. Bioph ys J. 52:39\n(7). Hoi et al.\, (2021) Nano Letters\, 21(7):2824\n(8). Axfo rd et al.\, (2022) Acta Cryst D78:52\n(9). Juarez et al (2021) Nature Comm s. 12:629\n(10). Birsh et al.\, (2023) J. Appl. Cryst. 56:1361\n\nhttps:// events.saip.org.za/event/272/contributions/10331/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10331/ END:VEVENT BEGIN:VEVENT SUMMARY:Fluorescence-Lifetime Super-Resolution Microscopy DTSTART;VALUE=DATE-TIME:20260326T090000Z DTEND;VALUE=DATE-TIME:20260326T094000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10330@events.saip.org.za DESCRIPTION:Speakers: Jörg Enderlein (University of Göttingen)\nRecent a dvancements in super-resolution microscopy have enabled unprecedented insi ghts into the spatial organization of cellular structures. In this talk\, I will present a series of methodological innovations that synergistically integrate fluorescence-lifetime single-molecule localization microscopy ( FL-SMLM) [1\,2]\, image scanning microscopy (ISM) [3\,4]\, and metal-/gr aphene-induced energy transfer (MIET/GIET) imaging [5–7]. These approac hes collectively offer isotropic three-dimensional resolution at the nanom eter scale\, multiplexed imaging capabilities\, and robustness against chr omatic aberrations.\n\nFirst\, I will discuss our work on MIET and GIET mi croscopy\, which exploit distance-dependent quenching phenomena near metal lic or graphene interfaces to determine the axial position of single emitt ers with sub-10 nm accuracy. The combination of MIET with dSTORM or DNA-PA INT provides truly isotropic 3D resolution\, extending the reach of locali zation microscopy into the axial dimension without interferometric complex ity.\n\nSecond\, I will highlight the development of fluorescence lifetime DNA-PAINT (FL-PAINT)\, a technique that enables multi-target super-resolu tion imaging through fluorescence lifetime multiplexing without fluid exch ange. By utilizing orthogonally designed imager strands conjugated to fluo rophores with distinct lifetimes\, we achieve simultaneous imaging of mult iple targets in the dense intracellular environment.\n\nLastly\, I will in troduce our latest development of fluorescence-lifetime image scanning mic roscopy SMLM (FL-iSMLM)\, which achieves a near twofold enhancement in lat eral resolution by integrating a single-photon detector array into a confo cal laser scanning microscope. This method combines the localization preci sion of ISM with the multiplexing power of fluorescence-lifetime detection \, enabling sub-5 nm resolution in fixed cells while simultaneously allowi ng discrimination of targets based solely on their fluorescence lifetimes. \n\nReferences\n[1] J. C. Thiele\, D. A. Helmerich\, N. Oleksiievets\, R. Tsukanov\, E. Butkevich\, M. Sauer\, O. Nevskyi\, and J. Enderlein\, Confo cal Fluorescence-Lifetime Single-Molecule Localization Microscopy\, ACS Na no 14\, 14190 (2020).\n[2] J. C. Thiele\, O. Nevskyi\, D. A. Helmerich\, M . Sauer\, and J. Enderlein\, Advanced Data Analysis for Fluorescence-Lifet ime Single-Molecule Localization Microscopy\, Front. Bioinform. 1\, 740281 (2021).\n[3] C. B. Müller and J. Enderlein\, Image Scanning Microscopy\, Phys. Rev. Lett. 104\, 198101 (2010).\n[4] N. Radmacher\, O. Nevskyi\, J. I. Gallea\, J. C. Thiele\, I. Gregor\, S. O. Rizzoli\, and J. Enderlein\, Doubling the resolution of fluorescence-lifetime single-molecule localiza tion microscopy with image scanning microscopy\, Nat. Photon. 18\, 1059 (2 024).\n[5] A. I. Chizhik\, J. Rother\, I. Gregor\, A. Janshoff\, and J. En derlein\, Metal-induced energy transfer for live cell nanoscopy\, Nature P hoton 8\, 124 (2014).\n[6] A. Ghosh\, A. Sharma\, A. I. Chizhik\, S. Isban er\, D. Ruhlandt\, R. Tsukanov\, I. Gregor\, N. Karedla\, and J. Enderlein \, Graphene-based metal-induced energy transfer for sub-nanometre optical localization\, Nat. Photonics 13\, 860 (2019).\n[7] J. C. Thiele\, M. Jung blut\, D. A. Helmerich\, R. Tsukanov\, A. Chizhik\, A. I. Chizhik\, M. Sch nermann\, M. Sauer\, O. Nevskyi\, and J. Enderlein\, Isotropic Three-Dimen sional Dual-Color Super-Resolution Microscopy with Metal-Induced Energy Tr ansfer\, Science Advances 8\, 14190 (2021).\n\nhttps://events.saip.org.za/ event/272/contributions/10330/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10330/ END:VEVENT BEGIN:VEVENT SUMMARY:LAAAMP: Light sources for Africa\, the Americas\, Asia\, Middle Ea st and Pacific. Fostering capacity building and collaboration through sync hrotron science. DTSTART;VALUE=DATE-TIME:20260326T141000Z DTEND;VALUE=DATE-TIME:20260326T142000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10332@events.saip.org.za DESCRIPTION:Speakers: Sizun Christina (French National Centre for Scientif ic Research)\nAdvanced Light Sources (AdLSs) have been recognized as impor tant large-scale facilities that provide a natural place for international scientific collaboration\, capacity building\, and networking. The except ionally intense light produced at these facilities allows scientists to ca rry out studies of the structure of proteins\, of new pharmaceutical compo unds\, study archaeological objects\, design new and better components for technological devices\, among many other applications. The establishment of these facilities contributes to boosting the technical and scientific d evelopment of the region and to improving the well-being of the general po pulation.\n \nFunding from the International Science Council (ISC) was awa rded in 2016 to the joint IUPAP-IUCr project “Utilisation of Light Sourc e and Crystallographic Sciences to Facilitate the Enhancement of Knowledge and Improve the Economic and Social Conditions in Targeted Regions of the World” Later on\, the Abdus Salam International Centre for Theoretical Physics (ICTP) and the International Union of Pure and Applied Biophysics (IUPAB) have joined the programme. LAAAMP has carried out different projec ts aimed at training scientists\, particularly early-career researchers in the different aspects of synchrotron-related techniques. The FAculty-STud ent (FAST) Teams awards provide funds for a Professor and a Student to spe nd two months at any of its 18 participating AdLSs. Other activities of LA AAMP have allowed the establishment of crystallography hubs in Benin (X-Te chLab) and in Jamaica (crXstal). Similar hubs are planned in other regions for the near future.\n \nLAAAMP coordinates the initiative “Advanced li ght source facilities to empower Global-South scientists for sustainable d evelopment” endorsed by the International Decade of Sciences for Sustain able Development (2024-2033). The aim of this initiative is to promote and establish new AdLSs in Africa\, Central Asia\, and the Latin America-Cari bbean region. In addition\, schools\, workshops\, and conferences are regu larly organized and supported by LAAAMP\, which will contribute to trainin g and secure future users of AdLSs.\n\nThe structure of LAAAMP and the pro grams developed and supported will be presented. Additional information ca n be accessed at https://laaamp.iucr.org/.\n\nhttps://events.saip.org.za/e vent/272/contributions/10332/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10332/ END:VEVENT BEGIN:VEVENT SUMMARY:How Instruct-ERIC can help Biophysics in Africa DTSTART;VALUE=DATE-TIME:20260326T142000Z DTEND;VALUE=DATE-TIME:20260326T143000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10328@events.saip.org.za DESCRIPTION:Speakers: Bryan Trevor Sewell (University of Cape Town)\nThe s tudy of the structure of biological entities ranging from macromolecules t o cells\, which underpins most of biophysics\, is called Integrated Struct ural Biology. The field continues to play a key role\, not only in biologi cal discovery but also in innovation and technology. Work in the field req uires equipment that is specialized and highly developed. The operation an d maintenance of such equipment depends on trained and experienced people. The Europeans have found that an effective model\, that gives the wider c ommunity access to this equipment\, is to create facilities to house and o perate it. Scientists from member countries can access the equipment\, bot h to learn how to use it and to conduct their own research. The coordinati on of this process is done through an entity called a European Research In frastructure Consortium (ERIC)\, which is funded through subscriptions fro m the member states. Instruct-ERIC (https://instruct-eric.org/)\, concerne d with Integrated Structural Biology\, is currently seeking to expand its footprint by recruiting participation from non-European organizations. Ent ry-level\, cost-free participation involves the signing of an MOU with Ins truct\, which entitles staff of the affiliate organization to respond to c ertain funding calls\, which will fund the use of the facilities and exper tise. At present\, the only organization in Africa with such an MOU in pla ce is the University of Cape Town (UCT). UCT is seeking funding from Horiz on to increase its level of involvement. Part of the obligation will be to increase national awareness of Instruct-ERIC with the ultimate goal of So uth Africa becoming a full member. A video introducing the services of In struct- ERIC is available on YouTube: https://youtu.be/HNwReIQDnhc?si=oYtD z0AXhQqqS1Gt\n\nhttps://events.saip.org.za/event/272/contributions/10328/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10328/ END:VEVENT BEGIN:VEVENT SUMMARY:Objective clustering algorithm applied to single-molecule FCP data DTSTART;VALUE=DATE-TIME:20260326T102000Z DTEND;VALUE=DATE-TIME:20260326T104000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10323@events.saip.org.za DESCRIPTION:Speakers: Michael Lovemore (Univeristy of the Witwatersrand)\n Bulk spectroscopic measurements of photosynthetic light-harvesting complex es report ensemble-averaged properties that often obscure the heterogeneit y and dynamic behaviour present at the level of individual complexes. Sing le-molecule fluorescence spectroscopy provides access to this hidden compl exity through measurements of fluorescence intensity and lifetime\; howeve r\, interpreting raw intensity–lifetime distributions can be challenging because broad\, overlapping populations frequently appear visually as onl y one or two states. Fucoxanthin chlorophyll protein (FCP) is the major li ght-harvesting complex of diatoms and contains Lhcx subunits that are impl icated in photoprotection under high-light conditions. We investigated the fluorescence dynamics of FCP complexes under different environmental cond itions using single-molecule intensity and lifetime measurements\, perform ing a comparative\, pH-dependent study of two FCP types to examine how Lhc x modulates the photoprotective behaviour. To objectively extract the unde rlying emissive states\, Gaussian mixture model (GMM) clustering was appli ed to the intensity–lifetime distributions. The optimal number of cluste rs was objectively determined using information criteria (AIC\, BIC\, ICL) and cluster-quality metrics to ensure statistical robustness. This approa ch revealed multiple emissive states beyond the simple two-state (quenched /unquenched) interpretation suggested by visual inspection\, enabling dire ct comparison across datasets and highlighting how environmental condition s and Lhcx content influence the accessibility and stability of the variou s photophysical states within FCP.\n\nhttps://events.saip.org.za/event/272 /contributions/10323/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10323/ END:VEVENT BEGIN:VEVENT SUMMARY:Multi-timescale fluorescence correlation spectroscopy of the main plant light-harvesting complex during aggregation stages DTSTART;VALUE=DATE-TIME:20260326T100000Z DTEND;VALUE=DATE-TIME:20260326T102000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10322@events.saip.org.za DESCRIPTION:Speakers: Francois Conradie ()\nLight-Harvesting Complex II (L HCII) is the most abundant photosynthetic membrane pigment-protein complex in higher plants\, enabling extremely efficient solar energy harvesting. Their light-harvesting function is finely controlled by processes that swi tch the complexes into a photoprotective state. LHCII aggregates\, that fe ature strong quenching of excitation light\, are often believed to be enha nce a plant’s photoprotective capability. Finding new ways to study thes e aggregates can lead to important insights into the fundamental mechanism s by which plants protect themselves against high sunlight intensities\, w hich could\, for example\, inform efforts to improve crop yields in a chan ging climate. In our project\, we have developed techniques that combine f luorescence correlation spectroscopy (FCS) and time-correlated single-phot on counting (TCSPC). The aggregation of LHCII was investigated at increasi ng levels by step-wise removal of detergent from low-concentration purifie d samples. Applying pulse-interleaved excitation (PIE) enabled advanced FC S to accurately measure translational and estimated rotational diffusion c oefficients\, yielding the hydrodynamic radii of LHCII during aggregation. Furthermore\, extending measurement times and using both pulsed and conti nuous excitation unveiled photophysics from microseconds down to picosecon d timescales. The results show a rich combination of dimensional informati on and excitation dynamics in these photosynthetic aggregates\, highlighti ng the importance of singlet-triplet annihilation when studying quenching in LHCII.\n\nhttps://events.saip.org.za/event/272/contributions/10322/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10322/ END:VEVENT BEGIN:VEVENT SUMMARY:Physicochemical Characterisation and Antibacterial Activities of C erium Oxide Nanoparticles DTSTART;VALUE=DATE-TIME:20260327T095000Z DTEND;VALUE=DATE-TIME:20260327T101000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10327@events.saip.org.za DESCRIPTION:Speakers: Fezile Motsoene (University of Johannesburg)\nDiabet ic wounds represent a complex biophysical microenvironment characterised b y sustained inflammation\, excess reactive oxygenated species\, impaired f ibroblastic proliferation\, and prevalent bacterial infections\, particula rly P. aeruginosa. Dysregulated redox homeostasis and altered cellular res ponses in diabetic tissue significantly compromise wound healing. Although conventional therapies\, including hormonal regulation\, pressure reducti on\, wound debridement\, and antibiotic treatments\, have long served as t he foundational approach to the management of diabetic wounds\, the increa sed disease recurrence and heightened bacterial progression have highlight ed the limitations of traditional methods. Therefore\, this study evaluate s the biophysical and bacterial interaction between green-synthesised ceri um oxide nanoparticles (CeO2 NPs) and both P. aeruginosa bacterial and mam malian wounded cells. The comprehensive physicochemical characterisation w ill be used to demonstrate the band gap energy\, hydrodynamic size\, morph ological properties\, and redox activity. Additionally\, the biophysical e valuation\, including antibacterial assays against P. aeruginosa\, will de monstrate a concentration-dependent response mediated through membrane int eractions. Moreover\, the application of CeO2 NPs in fibroblasts will enha nce the viability and proliferative responses under oxidative stress condi tions\, suggesting restoration of redox equilibrium and improved metabolic activity. These findings support the potential integration of complementa ry bioenergetic modulation strategies in future investigations. Furthermor e\, the collective findings will enhance the biophysical understanding of nanobio interactions in diabetic wounds while advocating the advancement o f redox-active plant-derived nanoparticles designed for resource-constrain ed environments.\n\nhttps://events.saip.org.za/event/272/contributions/103 27/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10327/ END:VEVENT BEGIN:VEVENT SUMMARY:In vitro characterisation of electrospun nanofibers for chronic di abetic wounds DTSTART;VALUE=DATE-TIME:20260327T093000Z DTEND;VALUE=DATE-TIME:20260327T095000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10326@events.saip.org.za DESCRIPTION:Speakers: Sinesipho Phalaso ()\nWound healing is a complex pro cess that can be impaired in conditions such as diabetes\, leading to chro nic wounds. Advanced dressings\, including nanofiber-based scaffolds\, off er enhanced interaction with the wound environment and support cellular ac tivity. In this study\, polycaprolactone (PCL) and gelatin (GEL) nanofiber s were fabricated via electrospinning to evaluate their potential for diab etic wound applications in vitro. Morphology was analyzed using field-emis sion scanning electron microscopy (FESEM)\, while biocompatibility\, poros ity\, water uptake\, and degradability were assessed. Nanofibers supported fibroblast attachment after 24 hours of incubation and demonstrated high porosity\, strong water absorption\, and controlled degradation. These fin dings indicate that electrospun PCL/GEL nanofibers are promising candidate s for chronic wound management. Future work will focus on antimicrobial dr ug loading to further enhance their therapeutical potential.\n\nhttps://ev ents.saip.org.za/event/272/contributions/10326/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10326/ END:VEVENT BEGIN:VEVENT SUMMARY:ANTIMICROBIAL AND ANTIOXIDANT ACTIVITY OF ZINC-MODIFIED COCONUT HU SK BIOCHAR DTSTART;VALUE=DATE-TIME:20260327T091000Z DTEND;VALUE=DATE-TIME:20260327T093000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10308@events.saip.org.za DESCRIPTION:Speakers: Ralph kwakye (university of health and allied scienc es)\nMicrobial resistance is increasing the global burden\, and the search for non-antimicrobial products useful in environmental as well as biologi cal applications continues. Coconut husk-derived biochar (BC) was synthesi sed by pyrolysis at 450 °C and then modified by zinc ion exchange to form zinc-loaded biochar (Zn-BC). The structural and morphological characteris ation by X-ray diffraction (XRD)\, scanning electron microscopy (SEM)\, an d Fourier-transform infrared spectroscopy (FT-IR) revealed the amorphous s tructure of carbon matrix loaded with adsorbed zinc-based crystalline doma ins\, maintaining the porous microstructure of the biochar. Antimicrobial activity showed no inhibition to BC (MIC > 1 mg mL⁻¹) against all teste d microorganisms. Zn-BC showed broad bactericidal and fungicidal activity of minimum inhibitory concentration (MIC) in all the examined organisms (0 .5 mg mL⁻¹). Activity ratios (MBC/MIC ≤ 4) proved bactericidal and fu ngicidal. In addition\, Zn-BC exhibited a moderate antioxidant activity co mpared to that of BC. Zn-BC exhibited up to 67.0 ± 1.5% radical scavengin g in the DPPH assay at 5 mg mL⁻¹\, and 61.7 ± 2.6% for unmodified bioc har. In the ABTS assay\, Zn-BC showed concentration-dependent scavenging w ith an inhibition of 57.6 ± 5.2% at 25 mg mL⁻¹\, higher than that of u nmodified BC. These findings indicate that zinc modification can convert c oconut husk biochar into an effective and versatile material with high ant imicrobial and moderate antioxidant activity.\n\nhttps://events.saip.org.z a/event/272/contributions/10308/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10308/ END:VEVENT BEGIN:VEVENT SUMMARY:Laser-Based Photobiomodulation Enhances Beta Cell Differentiation and Functional Insulin Production in Immortalised Adipose-Derived Stem Cel ls DTSTART;VALUE=DATE-TIME:20260325T134000Z DTEND;VALUE=DATE-TIME:20260325T140000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10316@events.saip.org.za DESCRIPTION:Speakers: Olukemi Daramola (University of Johannesburg)\nThe g eneration of functional insulin-producing beta (β)-cells from stem cells represented a promising therapeutic strategy for diabetes mellitus. Photob iomodulation (PBM)\, a non-invasive light-based approach\, has emerged as a potential regulator of cellular metabolism\, proliferation\, and differe ntiation through mitochondrial stimulation and bioenergetic modulation. Th is study investigated the effect of laser-based PBM on the differentiation of immortalised adipose-derived stem cells (ADSCs) into functional β-cel ls under both two-dimensional (2D) and three-dimensional (3D) culture cond itions.\nImmortalised ADSCs were exposed to defined laser parameters to ev aluate their capacity to enhance β-cell lineage commitment and functional insulin production. Cellular health\, viability\, and metabolic activity were assessed using multiple complementary assays. Intracellular adenosine triphosphate (ATP) quantification determined mitochondrial bioenergetic a ctivity\, while lactate dehydrogenase (LDH) release was measured to evalua te cytotoxicity and membrane integrity. Morphological changes associated w ith differentiation were examined using Giemsa staining\, and β-cell-spec ific insulin granule formation was confirmed using dithizone (DTZ) stainin g. Additionally\, Live/Dead assays were performed to assess overall cell v iability and survival within both 2D monolayer and 3D scaffold-based cultu re systems.\nIt was hypothesized that laser-based PBM enhanced mitochondri al activity\, improved cellular viability\, and promoted the generation of metabolically active\, insulin-producing β-cells\, with enhanced outcome s observed in 3D culture systems due to improved cell–cell and cell–ma trix interactions.\nThis study aimed to advance understanding of laser-bas ed PBM mechanisms in stem cell differentiation and to support the developm ent of non-invasive strategies for β-cell engineering and regenerative di abetes therapies.\n\nhttps://events.saip.org.za/event/272/contributions/10 316/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10316/ END:VEVENT BEGIN:VEVENT SUMMARY:BALANCING CELL COMPATIBILITY AND ANTIMICROBIAL EFFECTS OF 470 NM I N AN INFECTED HYPERGLYCAEMIC WOUND CELL MODEL DTSTART;VALUE=DATE-TIME:20260325T132000Z DTEND;VALUE=DATE-TIME:20260325T134000Z DTSTAMP;VALUE=DATE-TIME:20260815T102310Z UID:indico-contribution-272-10312@events.saip.org.za DESCRIPTION:Speakers: Francis Obeng Brenya (University of Johannesburg)\nF .O. Brenya1 and N.N. Houreld1*\n1Laser Research Centre\, University of Joh annesburg\, Johannesburg\, South Africa \nE-mail: nhoureld@uj.ac.za*\nAnti microbial photobiomodulation (aPBM) with blue light (400-490 nm) is a prom ising non-invasive adjunct therapy for infected chronic diabetic foot ulce rs (DFUs). Still\, its fluence-dependent effects on human dermal fibroblas ts remain poorly defined. This study investigated the fluence-dependent re sponse of fibroblasts (BJ-5ta) cultured under three conditions: normal (N) \, normal wounded (NW)\, and hyperglycaemic wounded (HW)\, with or without bacterial infection. BJ-5ta fibroblasts (6 × 10⁵ cells/mL) were co-cu ltured with Staphylococcus aureus\, Streptococcus pyogenes\, or Pseudomona s aeruginosa (1.5×10³ CFU/mL) and irradiated with 470 nm blue laser ligh t (power output 800 mW\; power density 88 mW/cm²) at 5\, 10\, 30\, 55\, 1 00\, or 120 J/cm². After 24 hours\, fibroblast viability\, migration\, mo rphology\, and bacterial survival were evaluated. Low fluences (5-10 J/c m²) maintained fibroblast viability at ≥90% across all uninfected model s. In contrast\, higher fluences (30-120 J/cm²) caused a marked\, dose- dependent decrease in fibroblast viability\, with the lowest values observ ed at 120 J/cm² in both normal and hyperglycaemic wounded models. Infec tion with S. aureus\, S. pyogenes\, and P. aeruginosa increased cytotoxic ity\, with each species showing the greatest reduction in fibroblast viabi lity at ≥55 J/cm². Fibroblast migration in the uninfected normal woun ded model decreased progressively at fluences over 30 J/cm²\, dropping to 22-30% at 120 J/cm². In infected normal wounded models\, migration d eclined in a species-dependent manner\, with minimum values of 22-30% for S. aureus\, 37-48% for S. pyogenes\, and 21-27% for P. aeruginosa at 120  J/cm². CFU counts were significantly reduced at 5-10 J/cm² for all species. At 30-120 J/cm²\, S. aureus and P. aeruginosa were unaffected\ , whereas S. pyogenes exhibited a sustained\, significant decrease in bact erial load. These results suggest a potential therapeutic window at 5-30  J/cm²\, within which fibroblast function is largely preserved while ba cterial burden is reduced\, supporting dose-optimised application of 470  nm aPBM in vitro.\n\nhttps://events.saip.org.za/event/272/contributions /10312/ LOCATION: URL:https://events.saip.org.za/event/272/contributions/10312/ END:VEVENT END:VCALENDAR