BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Jaws caught on the IMBL DTSTART;VALUE=DATE-TIME:20211125T023000Z DTEND;VALUE=DATE-TIME:20211125T024500Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4264@events01.synchrotron.org.au DESCRIPTION:Speakers: Daniel Hausermann (Australian Synchrotron (ANSTO))\n Maturational changes in feeding behaviour among sharks are associated with increased mineralisation of the teeth and jaws\, but this relationship ha s only been demonstrated in a few species. Large\, highly mobile shark spe cies are rarely available for detailed anatomical study\, despite their im portance for ecological health and widespread interest among the general p opulation. We examined the crania\, jaws\, and teeth of two great white sh arks (Carcharodon carcharias)\, a 2.3 m juvenile and a 3.2 m young adult.\ n\nThe CT scans used a 230 keV (mean energy) polychromatic beam from the 4 Tesla wiggler\, with a filtration of 6mmAl\, 6mmCu\, 3mmMo and 3mmPb. The detector was a Teledyne-Dalsa Xineos 3030HR with 100µm pixels\, a width of 300mm\, and a 1mm CsI converter for high efficiency at high energy. Ima ge noise was reduced by collecting 18\,000 projections per rotation to del iver an image quality good enough to segment out different tissue types. W ith a beam size of 300mm x 35mm\, the shark head was covered by ‘tiling ’\, and stitching the tiles\, with the full-head image made up of two co lumns and 21 tiles\, to image a 600mm x 520mm area. Total scan time was 9 hours.\n\nThe heads were also imaged using conventional CT and 7 Tesla MRI for finite element modelling of bite forces produced by the jaw musculatu re. These results will be compared with measurements of the difference in mineralisation of tooth and jaw cartilage between the two specimens to ass ess developmental changes in tooth and jaw hardness as the animals shift t heir diets from largely fish-based (juvenile) to larger prey\, such as sea ls\, scavenged whales and surfers (adults).\n\nhttps://events01.synchrotro n.org.au/event/146/contributions/4264/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4264/ END:VEVENT BEGIN:VEVENT SUMMARY:Determining the role of protein aggregation in COVID-19 DTSTART;VALUE=DATE-TIME:20211125T010000Z DTEND;VALUE=DATE-TIME:20211125T011500Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4279@events01.synchrotron.org.au DESCRIPTION:Speakers: Nicholas Reynolds (La Trobe University)\nCOVID-19 is primarily known as a respiratory disease caused by the virus SARS-CoV-2. However\, neurological symptoms such as memory loss\, sensory confusion\, cognitive and psychiatric issues\, severe headaches\, and even stroke are reported in as many as 30 % of cases and can persist even after the infect ion is over (so-called ‘long COVID’). These neurological symptoms are thought to be caused by brain inflammation and toxicity\, triggered by the virus infecting the central nervous system of COVID-19 patients\, however we still don’t understand the molecular mechanisms underpinning this ne urotoxicity. The neurological effects of COVID-19 share many similarities to neurodegenerative diseases such as Alzheimer's and Parkinson’s in wh ich the presence of cytotoxic self-assembled protein aggregates\, known as amyloid nanofibrils are a common hallmark. This led us to hypothesise tha t self-assembled amyloid aggregates maybe present in the proteome of SARS- CoV-2 and responsible for some of the neurological symptoms of COVID-19. I n this work we identified several peptides sequences within the proteome o f SARS-CoV-2 that have a strong tendency to spontaneously self-assemble in to amyloid aggregates. We performed an extensive characterisation of the i n vitro toxicity and biophysical properties of these assemblies using a va riety of techniques. We used data recorded at the SAXS/WAXS beamline at th e Australian Synchrotron to provide insights into the nanoscale morphology and molecular structure of these assemblies. Based on these results we in troduce the idea that cytotoxic amyloid aggregates of SARS-CoV-2 proteins are causing some of the neurological symptoms commonly found in COVID-19 a nd contributing to long COVID.\n\nhttps://events01.synchrotron.org.au/even t/146/contributions/4279/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4279/ END:VEVENT BEGIN:VEVENT SUMMARY:The silver bullet: using silver doped lanthanum manganite to selec tively target deadly brain cancer DTSTART;VALUE=DATE-TIME:20211125T004500Z DTEND;VALUE=DATE-TIME:20211125T010000Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4275@events01.synchrotron.org.au DESCRIPTION:Speakers: Abass Khochaiche (University of Wollongong)\n**Intro duction**\nTreatment of deadly cancers that are deep-seated within sensiti ve healthy tissue is limited to adequate targeting strategies. More speci fically\, brain and central nervous system cancers can be the most aggress ive\, have higher mortality rates and lower accessibility to chemotherapeu tic drugs. This study introduces the first in-depth analysis doped lantha num manganite (LAGMO) nanoparticles (NPs) as a brain cancer selective chem otherapeutic and radiation dose enhancer\n\n**Method**\nThe magnetic\, che mical and biological properties of LAGMO NPs at silver dopant levels of 0- 10% were investigated. Magnetic and chemical phases of LAGMO NPs were ana lysed with neutron diffraction using the ECHIDNA High-Resolution Powder Di ffractometer. Biocompatibility and combinational treatment strategies inv olved in vitro biological endpoint clonogenic assays\, live cell imaging a nd a cancer cell selectivity investigation.\n\n**Results**\nNeutron diffra ction revealed that 10% LAGMO NPs exhibit residual ferromagnetism at 300 K suggesting potential hyperthermia cancer treatment strategies. Biocompat ibility studies of LAGMO NPs with cancerous and non-cancerous cells displa yed completely cancer cell selective toxic response while non-cancerous ce ll growth was promoted. Clonogenic assays revealed a significant decrease in long-term survival of cancer cells with NPs and radiation therapy comp ared to radiation alone. \n\n**Conclusion**\nLAGMO NPs have potential to significantly improve targeted cancer treatment strategies. Their unique magnetic properties introduce a potential to induce cancer cell hypertherm ia alongside radiation treatment and improve clinical outcomes. Furthermo re\, they promote non-cancerous cell growth while severely damaging cancer cells alongside radiation. \n\n**References**\nKhochaiche\, Abass\, et a l. "First extensive study of silver-doped lanthanum manganite nanoparticle s for inducing selective chemotherapy and radio-toxicity enhancement." Mat erials Science and Engineering: C 123 (2021): 111970.\n\nhttps://events01. synchrotron.org.au/event/146/contributions/4275/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4275/ END:VEVENT BEGIN:VEVENT SUMMARY:Human MLKL is maintained by RIPK3 in an inactive conformation prio r to disengagement and cell death by necroptosis DTSTART;VALUE=DATE-TIME:20211125T003000Z DTEND;VALUE=DATE-TIME:20211125T004500Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4272@events01.synchrotron.org.au DESCRIPTION:Speakers: Yanxiang Meng (WEHI)\nNecroptosis is a caspase-indep endent form of programmed cell death that results in the compromise of pla sma membranes and release of inflammatory cellular contents. Dysregulated necroptosis has been shown to play a role in a range of different human pa thologies\, including ischemia-reperfusion injury\, inflammatory diseases\ , and inflammatory bowel disease. Phosphorylation of MLKL by the RIPK3 kin ase leads to MLKL oligomerization\, translocation to\, and permeabilizatio n of\, the plasma membrane to induce necroptotic cell death. The precise c horeography of MLKL activation remains incompletely understood. Here\, we used Monobodies\, synthetic binding proteins\, that bind the pseudokinase domain of MLKL to detect endogenous protein interactions within human cell s. We showed that MLKL is stably bound by RIPK3 prior to their disengageme nt upon necroptosis induction. Crystal structures of MLKL pseudokinase dom ain in complex with two different monobodies or RIPK3 kinase domain identi fied two distinct conformations of MLKL pseudokinase domain. These structu res support that human RIPK3 maintains MLKL in an inactive conformation pr ior to the induction of necroptosis. These studies provide further evidenc e that MLKL undergoes a large conformational change upon activation and id entify MLKL disengagement from RIPK3 as a key regulatory step in the necro ptosis pathway.\n\nhttps://events01.synchrotron.org.au/event/146/contribut ions/4272/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4272/ END:VEVENT BEGIN:VEVENT SUMMARY:A Comparison of Different Approaches to Image Quality Assessment i n Phase-Contrast Mammography DTSTART;VALUE=DATE-TIME:20211125T001500Z DTEND;VALUE=DATE-TIME:20211125T003000Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4268@events01.synchrotron.org.au DESCRIPTION:Speakers: Jesse Reynolds (University of Canterbury)\nPropagati on-based phase-contrast computed tomography (PB-CT) has the potential to i mprove breast cancer detection and characterisation compared to establishe d mammography techniques. The aim of this work is to find a quantitative i mage quality metric which could accurately predict the subjective clinical image quality assessment of PB-CT images made by radiologists as describe d in Taba et al. [1].\n\nThe experimental data analysed in this study incl uded PB-CT scans\, which were obtained for 12 full intact mastectomy sampl es at Imaging and Medical beamline (IMBL) of the Australian Synchrotron at different monochromatic X-ray energies and clinically relevant radiation doses. Quantitative image quality metrics including visibility\, signal to noise ratio (SNR)\, and spatial resolution\, were calculated for all PB-C T and conventional CT image sets using the open-source 3D Slicer (https:// www.slicer.org/) software. For each metric\, an objective image quality “score” was generated to match the subjective scoring provided by the radiologists. Weighting factors were then applied to the scores and a weig hted contrast to noise to resolution (CNR/res) score was calculated.\n\nTh e unscaled contrast and spatial resolution scores were both found to have a significant correlation with the radiologists’ scores with R values of 0.9223 and 0.8360 respectively\, while SNR had an insignificant correlati on\, with an R value of -0.6785. The weighted CNR/res score showed a signi ficant correlation to the radiologists’ scores with an R value of 0.9681 .\n\n[1] S. T. Taba et al.\, Academic radiology 28.1 (2021): e20-e26.\n\nh ttps://events01.synchrotron.org.au/event/146/contributions/4268/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4268/ END:VEVENT BEGIN:VEVENT SUMMARY:Disulfide bond formation between T-cell receptor and peptide antig en lowers the threshold of T cell activation DTSTART;VALUE=DATE-TIME:20211125T000000Z DTEND;VALUE=DATE-TIME:20211125T001500Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4261@events01.synchrotron.org.au DESCRIPTION:Speakers: Christopher Szeto (La Trobe Institute for Molecular Science)\nThe immune system is vigilant in detecting foreign pathogens. Ou r cells present peptides (p)\, small fragments of proteins\, atop Major Hi stocompatibility Complex (MHC) glycoproteins. These pMHC molecules are dis played on the cell’s surface and monitored by T cells of the immune syst em that patrol the body. T cells use their specialized T cell receptors (T CRs) to recognize and bind to pMHCs\, where the quality of binding influen ces T cell activation. Activated T cells are responsible for killing off i nfected cells and clearing infection. The contribution of individual param eters that dictate activation for this cell-to-cell TCR-pMHC interaction a re unclear. However\, a long reigning hypothesis is that the threshold of T cell activation can be determined by the dissociation constant or bindin g affinity. We have engineered a disulfide bond (DSB) between two cysteine residues introduced into a TCR and peptide that are known to form a TCR-p MHC complex. The formation of the DSB was validated using biophysical assa ys and X-ray crystallography. This approach represents a model in which th e covalently bonded TCR-pMHC do not dissociate\, prolonging the confinemen t time of the interaction almost indefinitely. When this TCR and pMHC mode l were reproduced in T cells\, we discovered that the DSB interaction was 10\,000-fold more sensitive in activating T cells than the wild-type count erpart without altering binding affinity. Thus\, we show that confinement time plays an important role in the activation of T cells\, which could b e useful in designing T cell therapies or peptide vaccines.\n\nhttps://eve nts01.synchrotron.org.au/event/146/contributions/4261/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4261/ END:VEVENT BEGIN:VEVENT SUMMARY:Membrane permeabilisation is mediated by distinct epitopes in mous e and human orthologs of the necroptosis effector\, MLKL DTSTART;VALUE=DATE-TIME:20211124T234500Z DTEND;VALUE=DATE-TIME:20211125T000000Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4259@events01.synchrotron.org.au DESCRIPTION:Speakers: Chris Horne (WEHI)\nNecroptosis is a lytic programme d cell death pathway with origins in innate immunity that is frequently dy sregulated in inflammatory diseases. The terminal effector of the pathway\ , MLKL\, is licensed to kill following phosphorylation of its pseudokinase domain by the upstream regulator\, RIPK3 kinase. Phosphorylation provokes the unleashing of MLKL’s N-terminal four-helix bundle (4HB or HeLo) dom ain\, which binds and permeabilises the plasma membrane to cause cell deat h. The precise mechanism by which the 4HB domain permeabilises membranes\, and how the mechanism differs between species\, remains unclear. Here\, w e identify the membrane binding epitope of mouse MLKL using NMR spectrosco py. Using liposome permeabilisation and cell death assays\, we validate K6 9 in the α3 helix\, W108 in the α4 helix\, and R137/Q138 in the first br ace helix as crucial residues for necroptotic signaling. This epitope diff ers from the phospholipid binding site reported for human MLKL\, which com prises basic residues primarily located in the α1 and α2 helices. In fur ther contrast to human and plant MLKL orthologs\, in which the α3-α4 loo p forms a helix\, this loop is unstructured in mouse MLKL in solution. Tog ether\, these findings illustrate the versatility of the 4HB domain fold\, whose lytic function can be mediated by distinct epitopes in different or thologs.\n\nhttps://events01.synchrotron.org.au/event/146/contributions/42 59/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4259/ END:VEVENT BEGIN:VEVENT SUMMARY:Sub cellular scale mapping of deuterated compounds by nanoSIMS DTSTART;VALUE=DATE-TIME:20211126T010000Z DTEND;VALUE=DATE-TIME:20211126T011500Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4282@events01.synchrotron.org.au DESCRIPTION:Speakers: jeremy bougoure (University of Western Australia)\nH igh resolution imaging mass spectrometry by nanoSIMS (nano scale secondary ion mass spectrometry) is a valuable method to observe deuterium accumula tion in any number of sample types. NanoSIMS analysis is a high resolutio n isotope and elemental imaging technique for solid sample surfaces\, allo ws for spatial resolution as low as 50nm and has high sensitivity which ma kes it an ideal method for observing deuterium accumulation in sub cellula r features of any number of sample types. The nanoSIMS method allows for simultaneous analysis of up to seven ion species\, meaning there is capac ity to pair deuterium analysis with other elemental or isotopic inquiry. I n this presentation\, fundamentals of nanoSIMS analysis are explained with emphasis on application to deuterium observation. The Microscopy Australi a supported nanoSIMS facility at The University of Western Australia has recently begun collaboration with users that have sourced deuterated compo unds from ANSTO based National Deuteration Facility and these examples wil l be discussed in detail.\n\nhttps://events01.synchrotron.org.au/event/146 /contributions/4282/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4282/ END:VEVENT BEGIN:VEVENT SUMMARY:Regional lung volume measures in small animal models from single p rojection X-ray images DTSTART;VALUE=DATE-TIME:20211126T004500Z DTEND;VALUE=DATE-TIME:20211126T010000Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4276@events01.synchrotron.org.au DESCRIPTION:Speakers: Dylan O'Connell (Monash University)\nRegional Lung v olume is a key parameter in assessing lung function and health. Computed T omography (CT) is considered the gold standard for measuring lung volume\; however\, it requires a relatively high radiation dose and typically has associated lower spatial and temporal resolution than X-ray projection ima ging. In this work\, we investigate whether regional lung volumes can be d etermined using 2D X-ray projections. The idea is that as the lung inflate s with air\, the attenuating tissue is displaced leading to a localised in crease in X-ray intensity. We imaged 13 New Zealand white rabbit kittens u sing high-resolution X-ray imaging and CT at the IMBL at various airway pr essures. From the 2D projections\, we converted changes in regional X-ray intensity through the lungs to changes in lung air volume using the Beer-L ambert law\, under the assumption that the lungs of the animal were compri sed of a single material (water). We measured the true air volumes from CT data for comparison. We found that relative changes in regional lung air volume derived from the 2D x-ray projections showed a coefficient of deter mination ($\\mathrm{R}^2$) of 0.97 with CT data. This technique\, therefor e\, provides a high speed\, low dose method for measuring regional changes in lung volume that we are now using for studying lung aeration at birth in preclinical animal models.\n\nhttps://events01.synchrotron.org.au/event /146/contributions/4276/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4276/ END:VEVENT BEGIN:VEVENT SUMMARY:Using X-ray crystallography to understand bushfire-induced seed ge rmination DTSTART;VALUE=DATE-TIME:20211126T003000Z DTEND;VALUE=DATE-TIME:20211126T004500Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4257@events01.synchrotron.org.au DESCRIPTION:Speakers: Sabrina Davies (The University of Western Australia) \nPassing the site of a bushfire a couple of weeks after it has burnt itse lf out\, you may notice a mass seed germination event taking place\, allow ing the bush to completely come back to life. This fascinating phenomenon occurs due to compounds in bushfire smoke called karrikins\, which act as triggers for seed germination.\n\nAlthough we know this process occurs\, w e don’t understand how karrikins interact with seeds or seedlings\, and what the little molecular machines – known as proteins – inside indivi dual cells do to allow a seed to germinate.\n\nX-ray crystallography is a technique where the atomic structure of a crystal can be determined via it s diffraction pattern when placed in the beam of an X-ray source. By cryst allising the proteins involved in karrikin signalling and shooting them at the MX beamlines at the Australian Synchrotron\, we are able to determine their structure and hence their function\; allowing us to piece together a complete picture of how karrikins work.\n\nOverall\, by understanding pr ocesses that control a plant’s growth and development\, we have new aven ues to explore in terms of finding sustainable agricultural techniques and effective methods of conservation and restoration.\n\nhttps://events01.sy nchrotron.org.au/event/146/contributions/4257/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4257/ END:VEVENT BEGIN:VEVENT SUMMARY:Biochemical Interaction of Few Layer Black Phosphorus with Microbi al Cells Using Synchrotron macro- ATR-FTIR DTSTART;VALUE=DATE-TIME:20211126T001500Z DTEND;VALUE=DATE-TIME:20211126T003000Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4256@events01.synchrotron.org.au DESCRIPTION:Speakers: Zoe Shaw (School of Engineering\, RMIT University)\n In the fight against drug resistant pathogenic bacterial and fungal cells\ , low dimensional materials have been shown as a promising form of alterna tive treatment method. Specifically\, few-layer black phosphorus (BP) has demonstrated its effectiveness against a wide range of pathogenic bacteria and fungal cells. In this work\, the complex biochemical interaction of B P with a series of microbial cells is investigated to provide a greater un derstanding of the antimicrobial mechanism. Synchrotron macro-attenuated t otal reflection–Fourier transform infrared (ATR-FTIR) spectroscopy is us ed to elucidate the chemical changes occurring outside and within the cell of interested after exposure to BP nanoflakes. The ATR-FTIR data\, couple d with advanced\, high-resolution microscopy\, reveals noticeable differen ces to the polysaccharide and nucleic acid spectral maps\, along with chan ges in amide protein structure when compared to untreated cells. This stud y provides a greater insight into the biochemical interaction of BP nanofl akes with microbial cells is given\, allowing for a better understanding o f the antimicrobial mechanism of action.\n\nhttps://events01.synchrotron.o rg.au/event/146/contributions/4256/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4256/ END:VEVENT BEGIN:VEVENT SUMMARY:Magnetically-guided particle delivery to airway surfaces for cysti c fibrosis gene therapy: Synchrotron-based visualisation and optimisation for improved in vivo lentiviral gene transfer DTSTART;VALUE=DATE-TIME:20211126T000000Z DTEND;VALUE=DATE-TIME:20211126T001500Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4255@events01.synchrotron.org.au DESCRIPTION:Speakers: Martin Donnelley (University of Adelaide)\nGene vect ors to treat cystic fibrosis lung disease should be targeted to the conduc ting airways\, as peripheral lung transduction does not offer therapeutic benefit. Viral transduction efficiency is directly related to the vector r esidence time. However\, delivered fluids such as gene vectors naturally s pread to the alveoli during inspiration. Extending gene vector residence t ime within the conducting airways is important\, but hard to achieve.\n\nG ene vector conjugated magnetic particles that can be guided to the conduct ing airway surfaces could improve targeting. Due to the challenges of in v ivo visualisation\, the behaviour of small magnetic particles on the airwa y surface in the presence of an applied magnetic field is poorly understoo d. The aim of this study was to use synchrotron imaging to visualise the i n vivo motion of a range of magnetic particles in live rat trachea to exam ine the dynamics and patterns of individual and bulk particle behaviour in vivo. \n\nSynchrotron X-ray imaging revealed the behaviour of magnetic pa rticles in stationary and moving magnetic fields\, both in vitro and in vi vo. Particles could not be dragged along the live airway surface with the magnet\, but during delivery deposition was focussed within the field of v iew where the magnetic field was the strongest.\n\nThese results show that magnetic particles and magnetic fields may be a valuable approach for imp roving gene vector targeting to the conducting airways in vivo.\n\nhttps:/ /events01.synchrotron.org.au/event/146/contributions/4255/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4255/ END:VEVENT BEGIN:VEVENT SUMMARY:Synchrotron CT dosimetry at the IMBL for low wiggler magnetic fiel d strength and spatial modulation with bow tie filters DTSTART;VALUE=DATE-TIME:20211125T234500Z DTEND;VALUE=DATE-TIME:20211126T000000Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4254@events01.synchrotron.org.au DESCRIPTION:Speakers: Stewart Midgley (Canberra Hospital)\nSynchrotron CT dose reduction was investigated for the IMBL wiggler source operated at lo wer magnetic field strength and for beam modulation with spatial filters p laced upstream from the sample. Beam quality at 25-30 keV for 1.4-3.0 T wa s assessed using transmission measurements with copper to quantify the inf luence of third harmonic radiation. The low energy operational limit is 24 -28 keV for 0.1-1% transmission by added filters\, 2 mm path length throug h silicon and 25 m of air. The upper limit is near 80 keV for wiggler fiel d 1.4 T\, approximately 100 keV for 2.0 T and extend beyond 100 keV for 3. 0-4.2 T. The harmonic radiation contribution is reduced for lower field st rengths. Measured dose rates suggest the influence of harmonics is insigni ficant above approximately 26 keV at 1.4 T and above 33 keV at 2.0 T. Rela tive to 3 T operation\, the mean dose rate in air is reduced to approximat ely 12% at 2 T and 4% at 1.4 T. Spatial filters were constructed from blo cks of perspex with circular voids of diameter matching the CT dosimetry t est objects. A calibrated ion chamber integrated absorbed dose to the phan tom during 360o rotation. CT dose indices (CTDI) were measured at 25-100 k eV for 3.0T only\, at the centre and periphery for 35-160 mm diameter pers pex phantoms. Beam shaping filters offer protection to the sample by reduc ing the peripheral and volumetric CTDI by about 10% for small objects and 20-30% for the larger samples.\n\nhttps://events01.synchrotron.org.au/even t/146/contributions/4254/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4254/ END:VEVENT BEGIN:VEVENT SUMMARY:Synchrotron infrared characterisation of SARS-CoV-2 virions for a new COVID-19 saliva test DTSTART;VALUE=DATE-TIME:20211126T033500Z DTEND;VALUE=DATE-TIME:20211126T035000Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4277@events01.synchrotron.org.au DESCRIPTION:Speakers: Bayden Wood (Centre for Biospectroscopy\, School of Chemistry\, Monash University)\nIn response to the COVID-19 pandemic the B iospectroscopy group within the Monash School of Chemistry have become par t of a research working group headed by Prof. Dale Godfrey and Prof. Damia n Purcell at the Doherty Institute to develop a new IR diagnostic for the detection of COVID-19. An infrared-based test would be reagent-less\, able to test hundreds of thousands using the same instrument\, be highly sensi tive and inexpensive\, producing results in minutes. This is cogent especi ally given the worldwide shortage of conventional testing kits and the lon g delays in getting results that in the case of virulent variants such as Delta\, are costing lives. The talk will focus on new developments in the arena of point-of-site COVID testing highlighting rapid diagnostic-based t ests and our new infrared based saliva screening test. We have modified a portable infrared spectrometer with purpose-built transflection accessory for rapid point-of-care detection of COVID-19 markers in saliva. Initially \, purified virion particles were characterized with Raman spectroscopy\, synchrotron infrared (IR) and AFM-IR. A data set comprising 171 transflect ion infrared spectra from 29 patients testing positive for SARS-CoV-2 by R T-qPCR and 28 testing negative\, was modeled using Monte Carlo Double Cros s Validation with 50 randomized test and model sets. The testing sensitivi ty was 93 % (27/29) with a specificity of 82 % (23/28) that included posit ive samples on the limit of detection for RT-qPCR. This high throughput in frared COVID-19 test is rapid\, inexpensive\, portable and utilizes sample self-collection\, thus minimizing the risk to healthcare workers and is i deally suited to mass or personalised screening in public and private sett ings.\n\nhttps://events01.synchrotron.org.au/event/146/contributions/4277/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4277/ END:VEVENT BEGIN:VEVENT SUMMARY:Structural insights into the unique modes of relaxin-binding and t ethered-agonist mediated activation of RXFP1 and RXFP2 DTSTART;VALUE=DATE-TIME:20211126T032000Z DTEND;VALUE=DATE-TIME:20211126T033500Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4274@events01.synchrotron.org.au DESCRIPTION:Speakers: Ashish Sethi (University of Melbourne)\nOur poor und erstanding of the mechanism by which the peptide-hormone H2 relaxin activa tes its G protein-coupled receptor\, RXFP1 and the related receptor RXFP2\ , has hindered progress in its therapeutic development. Both receptors pos sess unique ectodomains that comprise of an N-terminal LDLa module joined by a linker to a Leucine Rich Repeat (LRR) domain. Truncation of the N-ter minal LDLa module abolishes signalling for both receptors suggesting that the LDLa module is essential for activation and is postulated as a tethere d agonist\, induced to undergo a conformational change upon H2 relaxin bin ding. \n\nHere\, we use Small Angle X-ray Scattering (SAXS)\, NMR spectros copy\, cell-based receptor signalling assays to show that it is not the LD La module\, but rather a conserved motif (GDxxGWxxxF)\, immediately C-term inal to the LDLa\, that is the essential tethered agonist. Importantly\, t his motif associates with the LDLa module of both RXFP1 and RXFP2\, in dif ferent manners suggesting distinct mechanisms of activation. For RXFP1\, t he motif is flexible\, weakly associates with the LDLa module\, and requir es H2 relaxin binding to stabilize an active-state conformation. Conversel y\, the motif in RXFP2 does not possess the same flexibility as it does in RXFP1\, and appears to be more structured and closely associated with the LDLa module\, forming an essential binding interface for H2 relaxin. H2 r elaxin binding to RXFP2 needs both the LDLa module and the motif\, distinc t to RXFP1 and the tethered agonist activity of the motif is not driven by an induced conformational change in RXFP2\, also distinct to RXFP1. These results highlight distinct differences in relaxin mediated activation mec hanism of RXFP1 and RXFP2 which will aid drug development targeting these receptors.\n\nhttps://events01.synchrotron.org.au/event/146/contributions/ 4274/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4274/ END:VEVENT BEGIN:VEVENT SUMMARY:Antimicrobial and Anti-Inflammatory Gallium Implanted ‘Trojan Ho rse’ Surfaces for Implantable Devices DTSTART;VALUE=DATE-TIME:20211126T030500Z DTEND;VALUE=DATE-TIME:20211126T032000Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4269@events01.synchrotron.org.au DESCRIPTION:Speakers: Shiva Kamini Divakarla (The University of Sydney\, S ydney Nano Institute\, Faculty of Medicine and Health\, Sydney Pharmacy Sc hool\, Sydney\, NSW 2006\, Australia)\nA rapidly aging population\, high i ncidence of osteoporosis and trauma-related fractures\, and better health care access explain rapid surge in utilisation of orthopedic implantable d evices. Unfortunately\, many implants fail without strategies that synergi stically prevent infections and enhance the implant’s integration with h ost tissues. Here\, we propose a solution that builds on our pioneering wo rk on gallium (Ga)-enhanced biomaterials\, which show exceptional antimicr obial activity\, and combined it with defensin (De\, hBD-1)\, which has po tent anti-microbial activity in vivo as part of the innate immune system. Our aim was to simultaneously impart antimicrobial activity and anti-infla mmatory properties to polymer-based implantable devices through the modifi cation of the surfaces with Ga ions and immobilisation of De. Poly-lactic acid (PLA) films were modified using Ga implantation using the Surface Eng ineering Beamline of the 6MV SIRIUS tandem accelerator at ANSTO Australia\ , and subsequently functionalised with De. Ga ion implantation increased s urface roughness and increased stiffness of treated PLA surfaces and led t o the reduction in foreign body giant cell formation and expression of pro -inflammatory cytokine IL-1β. Ga implantation and defensin immobilization both independently and synergistically introduced antimicrobial activity to the surfaces\, significantly reducing total live biomass. We demonstrat ed\, for the first time\, that antimicrobial effects of De were enhanced b y its surface immobilization. Cumulatively\, the Ga-De surfaces were able to kill bacteria and reduce inflammation in comparison to the untreated co ntrol. These innovative surfaces have the potential to prevent biofilm for mation without inducing cellular toxicity or inflammation\, which is essen tial in enhancing integration of implantable devices with host tissues and hence\, ensure their longevity.\n\nhttps://events01.synchrotron.org.au/ev ent/146/contributions/4269/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4269/ END:VEVENT BEGIN:VEVENT SUMMARY:SPACE RADIATION AND INDIVIDUAL RADIOSENSITIVITY- ANSTO CAS & HUMAN HEALTH IN AIR BEAM EXPERIMENTS DTSTART;VALUE=DATE-TIME:20211126T025000Z DTEND;VALUE=DATE-TIME:20211126T030500Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4267@events01.synchrotron.org.au DESCRIPTION:Speakers: Melanie Lydia Ferlazzo (ANSTO)\nRadiation exposure i s a major limiting factor for long duration manned space flights. \nRadiat ion protection standards are based on the assumption that individuals are equally resistant to ionizing radiation. However\, for over a century\, th ere is evidence that humans do not respond equally to radiation. Particula rly\, the studies of secondary effects post-radiotherapy have shown a grea t variability among individuals. More specifically\, large discrepancies a mong astronauts after the same flight were observed. Recently\, from a col lection of hundreds of fibroblast cell lines derived from patients sufferi ng from genetic disease or post-radiotherapy radiosensitivity\, we have sh own that the delay in the nucleoshuttling of the ATM protein may cause a l ack of double strand break (DSB) recognition\, incomplete DSB repair and r adiosensitivity. Interestingly\, the model of the ATM nucleoshuttling was shown to be relevant not only for low-dose and repeated exposures\, but a lso for high-LET particles\, which renders this model compatible with spac e radiation exposure scenarios. Lastly\, this model could lead to a novel approach for radiation protection\, consisting of interventions to acceler ate ATM nucleoshuttling. Such an approach may help in developing efficien t countermeasures that could assist with manned space flights. In 2019-202 1\, teams from ANSTO CAS and Human Health have been collaborating to adapt the ANTARES beamline for in air irradiation of living matter and study th e effects of secondary radiation produced by interraction of cosmic and ga lactic rays with spacecraft shielding. DNA repair and mitochondrial activi ty processes will be studied.\n\nhttps://events01.synchrotron.org.au/event /146/contributions/4267/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4267/ END:VEVENT BEGIN:VEVENT SUMMARY:Studying Polysaccharides in Solution with SAXS and Molecular Dynam ics DTSTART;VALUE=DATE-TIME:20211126T023000Z DTEND;VALUE=DATE-TIME:20211126T025000Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4395@events01.synchrotron.org.au DESCRIPTION:Speakers: Martin (Bill) Williams (Massey University\, MacDiarm id Institute\, NZ)\nPolysaccharides are semi-flexible polymers composed of sugar residues with a myriad of important functions in-vivo\, including s tructural support\, energy storage and immunogenicity. The local conformat ion of such chains is a crucial factor governing their interactions. Tradi tionally this conformation has only been directly accessible in the solid- state\, using crystallographic techniques such as fibre diffraction. Howev er\, improvements in the quality of synchrotron-based X-ray scattering dat a means that conformation-dependent features can now be measured in soluti on. In tandem\, scattering predictions based on structures initiated from existing fibre x-ray diffraction data\, and then re-animated using molecul ar dynamics\, can now be performed. \n\nOur group has recently measured th e detailed small-angle x-ray scattering from a variety of anionic oligo- a nd poly-saccharides in solution. This talk will specifically present data obtained from experiments carried out on homogalacturonan\, alginate and c arrageenan and discuss their comparison with predictions based on our mole cular dynamics simulations. The remarkable agreement found provides unequi vocal evidence for the validity of our real-space atomistic models of the solution state structures. This technique is expected to be universally ap plicable for polysaccharides that consist of comparatively stiff glycosidi c linkages\, and to have extensive relevance for a number of biological ma cromolecules\, including glycosylated proteins.\n\nhttps://events01.synchr otron.org.au/event/146/contributions/4395/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4395/ END:VEVENT BEGIN:VEVENT SUMMARY:Structural\, Biochemical and Functional characterization of Salmon ella BcfH: an unusual Dsb-like fimbrial protein DTSTART;VALUE=DATE-TIME:20211124T034500Z DTEND;VALUE=DATE-TIME:20211124T040000Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4273@events01.synchrotron.org.au DESCRIPTION:Speakers: Pramod Subedi (La Trobe University)\nBacteria use fo lding enzymes to produce functional virulence factors. These foldases incl ude the Dsb family of proteins\, which catalyze a key step in the protein- folding pathway\, the introduction of disulfide bonds. The Dsb oxidative s ystem\, which includes an oxidative DsbA/DsbB pathway and an isomerase Dsb C/DsbD pathway\, is present in numerous bacterial species. Conventionally\ , Dsb proteins have specific redox functions with monomeric and dimeric Ds bs exclusively catalyzing thiol oxidation and disulfide isomerization\, re spectively. This contrasts with the eukaryotic disulfide forming machinery where the modular thioredoxin protein PDI mediates thiol oxidation and di sulfide reshuffling. In this study\, we identified and structurally and bi ochemically characterized a novel Dsb-like protein from Salmonella enteric a termed BcfH and defined its role in virulence. Encoded by a highly conse rved bcf (bovine colonization factor) fimbrial operon\, the Dsb-like enzym e BcfH forms a trimeric structure\, exceptionally uncommon among the large and evolutionary conserved thioredoxin superfamily. BcfH also displays ve ry unusual catalytic redox centers\, including an unwound α-helix holding the redox active site and a trans proline instead of the conserved cis pr oline active site loop. Remarkably\, BcfH displays both thiol oxidase and disulfide isomerase activities contributing to Salmonella fimbrial biogene sis. Typically\, oligomerization of bacterial Dsb proteins modulates their redox function\, with monomeric and dimeric Dsbs mediating thiol oxidatio n and disulfide isomerization\, respectively. The present study demonstrat es a further structural and functional malleability in the thioredoxin-fol d protein family. BcfH trimeric architecture and unconventional catalytic sites permit multiple redox functions emulating in bacteria the eukaryotic protein disulfide isomerase dual oxido-reductase activity.\n\nhttps://eve nts01.synchrotron.org.au/event/146/contributions/4273/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4273/ END:VEVENT BEGIN:VEVENT SUMMARY:Gd-TPP-DOTA reduces cell viability in cancer cells via synchrotron radiotherapy DTSTART;VALUE=DATE-TIME:20211124T033000Z DTEND;VALUE=DATE-TIME:20211124T034500Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4266@events01.synchrotron.org.au DESCRIPTION:Speakers: Ryan Middleton (ANSTO)\nHigh-Z elements have been p roposed as radiosensitisers in X-ray photon radiotherapy due to their emis sion of multiple high-LET photo- and Auger electrons following X-ray irrad iation. Gadolinium is a particularly attractive candidate radiosensitiser\ , since it can also be used as an MRI contrast agent. In this study\, we r eport on the efficacy of Gd-triphenylphosphonium salt-DOTA (Gd(III)-TPP-DO TA) for synchrotron microbeam radiation therapy dose enhancement. The comp ound utilises the mitochondrial targeting moiety triphenylphosphonium (TPP ) to accumulate Gd in the inner mitochondrial membrane. \n\nExperiments we re conducted using the dynamic mode option at hutch 2B of the Imaging and Medical Beamline at the Australian Synchrotron. Human glioblastoma multifo rme cells (T98G cell line) were cultured to 80-90% confluence in T12.5 fla sks. Approximately 24 hours prior to irradiation\, the cultures were eithe r treated with a 500 μM solution of Gd(III)DOTA-TPP or a vehicle control. Spatial dose distribution of synchrotron broad beam (BB) and single/multi ple microbeams were measured using a micron-scale X-Tream dosimetry system and Gafchromic films in air and at 2 cm depth in solid water (same depth as the monolayer of cells in T12.5 flasks). A total of 96 flasks were irra diated\, with doses of 0\, 1\, 2\, 3\, 4\, 5\, 10 and 16 Gy delivered in v alley (MRT) or uniformly (BB). Post irradiation\, each flask was re-seeded into 7 x 96 well-plates to perform the resazurin cell proliferation assay up to 7 days after irradiation. \n\nOur preliminary analysis indicates th at for cells irradiated by 3 Gy of BB or MRT radiation\, the addition of G d(III)DOTA-TPP results in a reduction in viable cell mass by 24.25% and 25 .79%\, respectively\, compared with untreated flasks.\n\nhttps://events01. synchrotron.org.au/event/146/contributions/4266/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4266/ END:VEVENT BEGIN:VEVENT SUMMARY:Investigating the role of Zn in glucose regulation using X-ray Flu orescence Microscopy and X-ray absorption near-edge structure spectroscopy DTSTART;VALUE=DATE-TIME:20211124T031500Z DTEND;VALUE=DATE-TIME:20211124T033000Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4263@events01.synchrotron.org.au DESCRIPTION:Speakers: Gaewyn Ellison (Curtin Innovation Health Research In stitute (CHIRI)\, Curtin University)\nZinc plays an important function in glucose regulation\, particularly within pancreatic islets\, the anatomica l home of the glucose regulating hormones insulin and glucagon. Glucose dy sregulation is a significant contributor to the epidemic of metabolic dise ases\, including diabetes\, that affect an increasing number of people. Zn is found in very high (mM) concentrations in insulin-secreting β-cells\, where it facilitates insulin synthesis and storage\, and is co-secreted w ith insulin\, subsequently acting as a signalling molecule. Zn dysregulati on is often coincident with impairment of insulin secretion\, but little i s known about the nature of the changes. Since a subset of the pool of Zn in islets is labile\, it is difficult to image in its *in vivo* situation using conventional techniques such as histochemistry. Not only do preparat ion steps such as washing displace Zn\, but some forms in which it exists are not readily discernible using conventional microscopy techniques. X-ra y fluorescence microscopy (XFM) and X-ray absorption near-edge structure s pectroscopy (XANES) offer several advantages in that tissue preparation is minimal\, facilitating the conservation of native states\, and all forms of Zn are not only detectable\, but are able to be discriminated by matchi ng spectra against an existing library of Zn forms. Here we report the pre liminary results from our study of Zn speciation and elemental mapping in murine islets from healthy or diabetes-prone animals in two age groups\, 1 4 (denoted young) or 28 (old) weeks. This work uses a library of biologica lly relevant Zn forms created in our laboratory\, and contributes to our u nderstanding of the role of Zn in glucose regulation in health and disease \, including aging.\n\nhttps://events01.synchrotron.org.au/event/146/contr ibutions/4263/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4263/ END:VEVENT BEGIN:VEVENT SUMMARY:Neutron Reflectometry Unravels Allergen-Lung Surfactant Monolayer Interactions in the Development of Pollen-Induced Thunderstorm Asthma DTSTART;VALUE=DATE-TIME:20211124T030000Z DTEND;VALUE=DATE-TIME:20211124T031500Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4253@events01.synchrotron.org.au DESCRIPTION:Speakers: Arslan Siddique (UNSW Sydney)\nPollen-induced thunde rstorm asthma outbreaks affect thousands of individuals globally. Australi ans in particular suffer from it every year. Pollens\, the major culprit i n thunderstorm asthma\, are biological microparticles produced by flowerin g species of the plants. Pollens encounter stormy environments including l ightning and humidity in thunderstorms\, which results in liberation of as sociated allergen proteins and probable reactions with reactive oxygen nit rogen species (RONS) from the environment\, before inhalation. Since aller gen proteins are much smaller in size than whole pollen\, they can travel deep down in the lower airways where they initially interact with the lung surfactant monolayer present within the lumen of alveoli. Although meteor ological\, pathological and immunological analyses support the role of pol len allergens in exacerbating asthma\, the physicochemical basis of this p henomenon is underinvestigated. \n\nIn this talk\, we present a model syst em to study the interactions between an allergen protein and a lung surfac tant monolayer composed of solid-supported dipalmiptoylphosphatidylcholine (DPPC) monolayer. We mimic the stormy environment with plasma-activated w ater (PAW) and employ advanced analytical tools and techniques such as qua rtz crystal microbalance with dissipation (QCM-D) and neutron reflectometr y (NR) to investigate the effect of RONS on the allergen protein and its s ubsequent interactions with the DPPC monolayer. Our experimental analysis revealed the attachment of RONS on the allergens when exposed to the PAW\, and QCM-D showed mass adsorption profiles. Furthermore\, NR showed the mo nolayer insertion and aggregation propensity of the allergens\, providing a deeper mechanistic insight into these interactions. The findings of this research will enable effective diagnostic strategies and therapeutics for the treatment of thunderstorm asthma.\n\nhttps://events01.synchrotron.org .au/event/146/contributions/4253/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4253/ END:VEVENT BEGIN:VEVENT SUMMARY:Imaging Breast Microcalcifications Using Dark-Field Signal in Prop agation-Based Phase-Contrast Tomography DTSTART;VALUE=DATE-TIME:20211124T013500Z DTEND;VALUE=DATE-TIME:20211124T015000Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4278@events01.synchrotron.org.au DESCRIPTION:Speakers: Alaleh Amin zadeh ()\nBreast microcalcifications are an important primary radiological indicator of breast cancer. However\, m icrocalcification classification and diagnosis can be still challenging fo r radiologists due to limitations of the standard 2D mammography technique \, including spatial and contrast resolution. In this study\, we propose a n approach to improve the detection of microcalcifications in propagation- based phase-contrast X-ray tomography (PB-CT) of breast tissues. Five fres h mastectomies containing microcalcifications were scanned at the Imaging and Medical beamline of the Australian Synchrotron at different X-ray ener gies and radiation doses. Both bright-field and dark-field images were ext racted from the same data sets using different image processing methods [1 ]. A quantitative analysis was performed in terms of visibility and contra st-to-noise ratio of microcalcifications. The results show that the visibi lity of the microcalcifications in the dark-field images is more than two times higher compared to the bright-field images. Dark-field images have a lso provided more accurate information about the size and shape of the mic rocalcifications [2]. Therefore\, dark-field PB-CT images are likely to he lp radiologists evaluate the probability of breast cancer more effectively . This work has been conducted in the course of developing a medical imagi ng facility at the Australian Synchrotron for advanced breast cancer imagi ng.\nReferences:\n[1] T. E. Gureyev\, et al.\, Phys. Med. Biol. 65\, 21502 9\, 2020.\n[2] A. Aminzadeh et al.\, submitted.\n\nhttps://events01.synchr otron.org.au/event/146/contributions/4278/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4278/ END:VEVENT BEGIN:VEVENT SUMMARY:Spectroscopic Analysis of Age-Related Changes in the Brain Lateral Ventricles During Ageing DTSTART;VALUE=DATE-TIME:20211124T012000Z DTEND;VALUE=DATE-TIME:20211124T013500Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4271@events01.synchrotron.org.au DESCRIPTION:Speakers: Ashley Hollings (School of Molecular and Life Scienc es\, Curtin University\, GPOBox U1987\, Bentley Western Australia 6845\, A ustralia. Curtin Health Innovation Research Institute\, Curtin University\ , Bentley\, Western Australia 6102\, Australia.)\nAlzheimer’s disease is the most common form of dementia and poses significant health and economi c concerns. Currently\, the disease has no cure\, and it is expected that over 1 million people could be affected by 2058 in Australia alone. The co ntent and distribution of metals such as Fe\, Cu\, Zn is known to change i n the ageing brain and thus\, increased understanding of the mechanistic r ole of metal dis-homeostasis may illuminate new therapeutic strategies. Th e brain lateral ventricles\, which play a role in controlling metal and io n transport\, have shown increasing levels of copper surrounding their wal ls with ageing. As a redox active metal\, copper can induce oxidative stre ss which is a process that occurs during Alzheimer’s disease onset and p rogression. Our research group has been interested in determining whether the age-related elevation of copper surrounding the lateral ventricles is inducing oxidative stress in that region. In this study\, we have utilised X-Ray Absorption Spectroscopy (XAS) at the Stanford Synchrotron Radiation Lightsource to analyse different chemical forms of sulfur and measure oxi dative stress by analysis of disulfides. Additionally\, we used the infrar ed microscopy beamline at the Australian Synchrotron to identify whether a ny other markers of oxidative stress were present around the ventricles. F urther insights into metal dis-homeostasis and its influence on other bioc hemical pathways\, may help to reveal some of the neurochemical mechanisms involved in progression of Alzheimer’s disease. In turn\, this may help pave the way for potential preventative or therapeutic models.\n\nhttps:/ /events01.synchrotron.org.au/event/146/contributions/4271/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4271/ END:VEVENT BEGIN:VEVENT SUMMARY:Structural insights into the ferroxidase and iron sequestration me chanisms of ferritin from Caenorhabditis elegans DTSTART;VALUE=DATE-TIME:20211124T010500Z DTEND;VALUE=DATE-TIME:20211124T012000Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4265@events01.synchrotron.org.au DESCRIPTION:Speakers: Tess Malcolm (Bio21 Molecular Science and Biotechnol ogy Institute)\nIron is an essential trace element that\, when in excess\, becomes highly toxic [1]. Intracellular iron concentration must be strict ly regulated by a network of interacting mechanisms [2]. Ferritin is a ubi quitous iron-storage protein that forms a highly conserved 24-subunit sphe rical cage-like structure. Ferritin catalyses the oxidation of iron (II) t o iron (III) and sequesters the newly oxidised iron (III) as a mineral cor e to prevent cellular damage [3]. In this study\, we use the model organis m\, Caenorhabditis elegans\, to investigate iron uptake\, oxidation\, stor age and release by ferritin. \nC. elegans expresses two ferritin proteins \, FTN-1 and FTN-2\, which both exhibit ferroxidase activity [4]. FTN-2 fu nctions at a rate significantly faster than FTN-1 despite conservation of all catalytic residues\, suggesting that structural differences at a locat ion distinct to the ferroxidase centre may influence catalytic activity. W e solved the X-ray crystal structures of FTN-1 (1.84 Å) and FTN-2 (1.47 Å)\, and the cryo-EM structure of FTN-2 (1.88 Å). FTN-1 and FTN-2 both a dopt the conserved 24-subunit cage-like structure and bind one iron (II) i n the ferroxidase centre of each chain. We postulate that iron (II) access es the ferroxidase centre through a three-fold symmetrical pore. This pore is notably larger and more negatively charged in the FTN-2 structure and may facilitate easier access of iron (II) to the ferroxidase centre\, resu lting in a faster catalysis rate. \nThese structural insights further ou r understanding of the mechanisms used by ferritin to regulate iron storag e and the overall role of ferritin in iron homeostasis.\n\nhttps://events0 1.synchrotron.org.au/event/146/contributions/4265/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4265/ END:VEVENT BEGIN:VEVENT SUMMARY:Investigating the Therapeutic Benefit of Spermidine in a Pre-Clini cal Model of Muscular Dystrophy DTSTART;VALUE=DATE-TIME:20211124T005000Z DTEND;VALUE=DATE-TIME:20211124T010500Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4262@events01.synchrotron.org.au DESCRIPTION:Speakers: Lauryn Schaddee Van Dooren (University of Melbourne) \nResearch into treatment for Duchenne Muscular Dystrophy (DMD) typically focuses on deterioration of muscle\, however bone health is also severely compromised. Current treatment with corticosteroids exacerbate bone loss\, so novel therapies targeting both muscle and bone are needed. Studies on bone health in a pre-clinical model\, mdx mice\, are limited and have conf licting results. \nObjective of study: To characterise aspects of bone hea lth in mdx mice and investigate whether spermidine might attenuate disease symptoms and spare bone. \nBone structure and function were assessed in 1 6-week-old mdx mice femurs by three-point bending\, microarchitectural ass essment using the Imaging and Medical Beamline (IMBL) at the Australian Sy nchrotron\, and by histological analysis. Cortical thickness and cortical bone area fraction were lower in dystrophic mice compared to wild-type con trols (WT). No differences were observed in metaphyseal trabecular bone mo rphometry. Three-point bending indicated that mdx femurs required less str ess to reach yield point and failure but were able to sustain damage for a longer period (post-yield displacement) compared to WT mice. Despite this \, mdx femurs required more energy to reach failure. Histology revealed lo wer osteoblast numbers in mdx mice. Spermidine treatment did not appear to compromise bone health in either WT or mdx mice which is important as cur rent treatments typically worsen bone quality. This study provides novel d ata about aspects of skeletal morphology in mdx mice at 16 weeks of age\, and provides new techniques using pre-clinical models to investigate poten tial therapies for DMD patients that might target both muscle and bone.\n\ nhttps://events01.synchrotron.org.au/event/146/contributions/4262/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4262/ END:VEVENT BEGIN:VEVENT SUMMARY:Hepatic lipid composition in dietary models of high iron NAFLD inv estigated with Synchrotron Infrared and X-Ray Fluorescence microscopy DTSTART;VALUE=DATE-TIME:20211124T003500Z DTEND;VALUE=DATE-TIME:20211124T005000Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4260@events01.synchrotron.org.au DESCRIPTION:Speakers: Clinton Kidman (Curtin University)\, Cyril Mamotte ( Curtin University)\nHepatocytes are essential for maintaining homeostasis of mammalian iron and lipid metabolism. Serious health consequences have b een linked to dysregulation of both areas. One such consequence is non-alc oholic fatty liver disease (NAFLD). Approximately 30% of individuals with NAFLD demonstrate a moderate increase in hepatic iron\; however\, the mech anism and metabolic consequences remain under-investigated. We assessed th e metabolic consequences using mice fed either a control or high fat (HF) diet\, with or without high iron. Attenuated Total Reflection Infrared Mic roscopy (Macro-ATR) at the Australian Synchrotron was used to investigate lipid composition and distribution\, and X-Ray Fluorescence Microscopy (XR F) at the Diamond Light Source (UK) was used to determine subcellular iron concentration and distribution. Peri-portal hepatocytes of HF fed animals exhibited elevated lipid parameters\, including ester and free fatty acid concentrations ~7x that of controls (P\n\nhttps://events01.synchrotron.or g.au/event/146/contributions/4260/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4260/ END:VEVENT BEGIN:VEVENT SUMMARY:Structures of biliary micelles during solubilisation of lipids mim icking the digestion products of human and bovine milk DTSTART;VALUE=DATE-TIME:20211124T002000Z DTEND;VALUE=DATE-TIME:20211124T003500Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4258@events01.synchrotron.org.au DESCRIPTION:Speakers: Andrew Clulow (ANSTO Australian Synchrotron)\nMilk i s our sole source of nutrition for the first six months of life and milk l ipids carry fat-soluble nutrients through the gut as well as providing mos t of the energy we consume with milk. The digestion and absorption of lipi ds\, predominantly triglycerides\, and entrained nutrients is therefore im portant for survival and growth. Milk triglycerides are regarded amongst t he most chemically complex mixtures\, their composition is species-depende nt and determines the mixture of fatty acids and monoglycerides that form during their digestion. Most lipid digestion takes place in the small inte stines where bile salts mixed with phospholipids in the intestinal fluids form a colloidal sink into which the poorly-soluble digestion products can partition and be absorbed at the intestinal walls. This work describes at tempts to simulate how the structures of biliary micelles change when they absorb milk digestion products under intestinal conditions. Mixtures of f atty acids and monoglycerides were prepared to mimic the digestion product s of human and bovine milk. The chemical complexity of the mixtures was va ried by including between four and eight different lipid chain types in th e digestion product mixtures. The effect of pH on micelle structure was al so studied within the range of pH 6.4-7.7\, consistent with the increase i n pH along the intestinal tract. The structural differences when these com plex lipid mixtures were solubilised by bile salt/phospholipid micelles we re identified using the SAXS/WAXS beamline at the ANSTO Australian Synchro tron. The lipid composition was found to be a primary driver of micelle sh ape and size\, with pH having a secondary affect in reducing aggregate for mation at higher pH.\n\nhttps://events01.synchrotron.org.au/event/146/cont ributions/4258/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4258/ END:VEVENT BEGIN:VEVENT SUMMARY:The Death Kiss: understanding how the zombie protein\, MLKL\, is t riggered to kill cells by necroptosis DTSTART;VALUE=DATE-TIME:20211124T000000Z DTEND;VALUE=DATE-TIME:20211124T002000Z DTSTAMP;VALUE=DATE-TIME:20260712T183317Z UID:indico-contribution-1301-4284@events01.synchrotron.org.au DESCRIPTION:Speakers: James Murphy (Walter and Eliza Hall Institute of Med ical Research)\nIn 2012\, Mixed lineage kinase domain-like (MLKL)\, a cata lytically-dead (“zombie”) cousin of conventional protein kinases\, ter med a pseudokinase\, was implicated as the key effector in the programmed necrosis (or necroptosis) cell death pathway. This pathway has been implic ated in innate immunity\, the pathogenesis of inflammatory diseases\, and tissue injury arising from ischemia-reperfusion. As a result\, an improved fundamental knowledge of MLKL’s activation mechanism is of enormous int erest as we and others look to target the pathway therapeutically. \n\nHer e\, I will describe our recent work dissecting the chronology of events in this pathway using novel tools\, biochemistry\, microscopy\, proteomics a nd structural biology methods. Our structural studies were enabled by the MX and SAXS beamlines at the Australian Synchrotron and isotopic protein l abelling at the National Deuteration Facility.\n\nhttps://events01.synchro tron.org.au/event/146/contributions/4284/ LOCATION:Online URL:https://events01.synchrotron.org.au/event/146/contributions/4284/ END:VEVENT END:VCALENDAR