Congratulations to Rodney Dharma and Xinyi Yang for receiving Honourable Mentions in the Thomas Cherry Prize at the 2025 Australian and New Zealand Industrial and Applied Mathematics (ANZIAM) conference. Rodney spoke about “Bacterial encounter rates and residence times in microbial symbiosis“, and Xinyi’s presentation was entitled “Resolving the hydrodynamics of non-spherical microswimmers“.
Our latest paper is a collaborative effort with Professor Takuji Ishikawa (Tohoku University, Japan) and Professor Tim Pedley (University of Cambridge, UK). In this study, published in Journal of Fluid Mechanics, dynamic simulations of a suspension of active particles in Poiseuille flow, situated between two parallel walls, were conducted by Stokesian dynamics assuming negligible inertia. While previous studies have reported negative viscosity of pusher suspensions, this study shows that the effective viscosity of bottom-heavy puller suspensions can be negative for Poiseuille upflow.
Congratulations to the team – in particular Riccardo Foffi and Jonasz Słomka from ETH Zürich – for this latest publication in Proceedings of the National Academy of Sciences.
Chemotaxis can aid bacteria in navigating the gradients of chemicals exuded by phytoplankton cells, yet these gradients can often be noisy, and the type of noise experienced by chemotactic bacteria depends on the size of the phytoplankton cell. Combining the size dependence of the limits of chemotactic detection and cell–cell encounters, we show that bacteria searching for phytoplankton can benefit the most from chemotaxis toward small rather than large cells.
Dr Douglas Brumley has been promoted to Associate Professor (Level D) at The University of Melbourne (effective January 2025).
We are excited to receive a Research Grant from the Gordon and Betty Moore Foundation, as part of the Symbiosis Model Systems Initiative. The project, “New Tools for Advancing Model Systems in Aquatic Symbiosis“, is led by Douglas Brumley and in collaboration with Professor Linda Blackall.
Congratulations to Xinyi Yang, for the first paper from her PhD, “Escape motility of multicellular magnetotactic prokaryotes“, published today in Journal of the Royal Society Interface. Together with Prof. Manu Prakash at Stanford University, we examined how multicellular bacteria are capable of simultaneously responding to magnetic fields and oxygen gradients.
Congratulations to Riccardo Foffi and Jonasz Słomka from ETH Zürich for leading this work, “Slower swimming promotes chemotactic encounters between bacteria and small phytoplankton”. A preprint is now available on arXiv here: https://arxiv.org/abs/2410.03641.
Chemotaxis enables marine bacteria to increase encounters with phytoplankton cells by reducing their search times, provided that bacteria detect noisy chemical gradients around phytoplankton. To date, it has remained unclear how phytoplankton size and bacterial swimming speed affect bacteria’s gradient detection ability and search times for phytoplankton. We found that chemotaxis can substantially decrease search times for small phytoplankton, but this advantage is highly sensitive to variations in bacterial phenotypes or phytoplankton leakage rates. By contrast, chemotaxis towards large phytoplankton cells reduces the search time more modestly, but this benefit is more robust to variations in search or environmental parameters.
Congratulations to Filippo and Arash for leading this work, “Machine learning driven image segmentation and shape clustering of algal microscopic images obtained from various water types”.
Accurate identification and quantification of algae and cyanobacteria are vital for ecological research, water quality monitoring, and public health safety. However, traditional methods of manually counting and morphologically identifying these microorganisms are time-consuming and prone to human error. This work, published in Computational and Structural Biotechnology Reports uses Machine Learning to automate cell identification and enumeration from microscopy images.
Congratulations to Peijing Li for completing the PhD degree! Co-supervised with Jesse Collis and John Sader, Peijing’s thesis examined the streaming forces acting on small solid particles in viscous fluids.
Thesis Title: The steady streaming flows generated by spherical particles suspended in acoustic waves.
Summary: This doctoral project primarily aims to investigate the association between radiation and streaming forces acting on small solid particles and the patterns observed in the structures of acoustic streaming flows around them. The focus is on understanding the net impact of non-linear effects resulting from an oscillatory flow around a solid particle, encompassing both the dynamic effects on the particle and the structure of the time-averaged flow field around it, considering combined oscillations, compressibility, viscosity, and additional influence of inertia.
Douglas Brumley is excited to join the Editorial Board for PLOS Computational Biology, a journal dedicated to investigating living systems at all scales, through the application of computational methods.
Douglas Brumley is excited to join as an Associate Editor of the Bulletin of Mathematical Biology, a journal devoted to research at the junction of computational, theoretical, and experimental biology.
On Monday 12 August, Dr Douglas Brumley, Professor Jennifer Flegg, and Associate Professor Guoqi Qian joined in a lively panel, hosted by science communicator Graham Phillips, to discuss how they dedicate their working days to helping people and our planet using the power of numbers, big data and new mathematical models. A short summary of the event is shown below: https://science.unimelb.edu.au/about/news/model-citizens-how-mathematicians-are-helping-the-planet.
A recording of the Lecture is also available here: https://www.youtube.com/watch?v=O-usdJI174g.
Congratulations to Tristan Bunnage for completing the Master of Science (Mathematics and Statistics). Tristan’s research project, co-supervised with Dr. Edward Hinton, examined “Miscible Viscous Fingering Subject to an Oscillating Injection”.
Congratulations to Vicky Waymouth for being awarded $6000 through the Women in Science of the environment (WISE) Fellowship. Vicky (co-supervised with Professor Michelle Watt) will use the awarded funds to attend the 12th International Conference on Mycorrhizae (ICOM12) in Manchester this year.
We are excited to see that our paper, “Swimming towards each other: the role of chemotaxis in bacterial interactions“, has been featured on the cover of this month’s issue of Trends in Microbiology. Our work, published in collaboration with colleagues at University of Technology Sydney and ETZ Zurich, highlights how chemotactic sensing could represent an important, but largely overlooked, phenotype within bacterial interactions.
Congratulations to Dr. Pranali Deore for her latest publication, “Unique photosynthetic strategies employed by closely related Breviolum minutum strains under rapid short-term cumulative heat stress“.
While variation in thermal tolerance between species is well documented, variation between conspecific strains is understudied. This paper, published in Journal of Experimental Botany, found that Breviolum minutum strains employ distinct photoprotective strategies, resulting in different upper thermal tolerances.
Congratulations to Xinyi Yang, whose poster, “Microswimmers in vortical flows”,
received an Honourable Mention at the 7th Microscale Ocean Biophysics Meeting on Heron Island this week. This meeting brought together more than 70 participants working across many disciplines, including marine biology, ecology, physical oceanography, soft and active matter, applied mathematics, and engineering.
Congratulations to MSc student Tristan Bunnage (co-supervised with Dr. Edward Hinton), who won second prize ($125) at the one-day meeting of the Australian and New Zealand Industrial and Applied Mathematics Society (ANZIAM, Victorian Branch). Tristan’s talk was entitled “Miscible viscous fingering under an oscillating background flow”.
Congratulations to Peijing Li, for the second paper from her PhD, published today in Journal of Fluid Mechanics. This paper identifies the mechanism underlying reversal of propulsion direction of spherical particles trapped in an acoustic standing wave. This has implications for studying the flow field around particles of non-spherical geometries and for modelling suspensions of particles in acoustic fields.
Congratulations to Antony Selvan, who won the Best Student Paper Prize at the 2024 Mathematical Biology Special Interest Group (MBSIG) workshop at the University of South Australia. Antony’s paper, entitled “Point torque representations of ciliary flows” developed new singularity methods for representing the flow fields generated by cilia and flagella. This prize is for an exceptional paper in the field of mathematical biology, and comes with a cash award of 300 AUD, and an invitation to speak at the workshop.
Congratulations to Xinyi Yang for receiving an Honourable Mention in the Thomas Cherry Prize at the 2024 Australian and New Zealand Industrial and Applied Mathematics (ANZIAM) conference. Xinyi’s talk was entitled “Escape motility of multicellular magnetotactic prokaryotes”.
Our preprint posted on bioRxiv, led by Dr. Pranali Deore, uses fluorescence lifetime imaging microscopy (FLIM) and FISH to visualise intracellular bacteria in Symbiodiniaceae. Significant changes in the abundance of intracellular bacteria relative to autofluorescence in B. minutum cells were observed at initiation of light and dark conditions. We suggest that the onset of bacterial endosymbiosis is linked to the photoperiod driven changes in B. minutum life stages.
Our latest work, published in collaboration with colleagues at University of Technology Sydney and ETH Zurich, examines the role of chemotaxis in bacterial interactions. The paper in Trends in Microbiology discusses how chemotactic sensing could represent an important, but largely overlooked, phenotype within bacterial interactions, and play a major role in shaping cooperative and competitive relationships.
Artwork by Philippe Plateaux.
Howie Zhou is a Masters student at the School of Mathematics and Statistics. His research investigates ciliary flows generated by coral surfaces, in the presence of non-Newtonian fluids.
Olle is a PhD student (co-supervised with Prof. Madeleine van Oppen) at the University of Melbourne’s School of Mathematics and Statistics. His research topics include motility and chemotaxis of Symbiodiniaceae microalgae, in silico and in vitro studies using microfluidics, and modelling the effect of stressors on the coral holobiont.
Congratulations to Antony Selvan for the first paper from his PhD. This work, published in Physical Review Fluids, employs a point torque (or “rotlet”) model to capture the time-averaged ciliary flow above a planar rigid wall.
Congratulations to Peijing Li for the first paper from her PhD, published recently in Journal of Fluid Mechanics. This work explores the streaming flow generated by a sphere in a fluid undergoing rectilinear oscillation.
Rebecca Rasmussen’s research uses experiments and mathematical modelling to investigate the flow patterns produced by the motion of an aquatic insect, the water boatman, exploring what ecological advantages may be conferred by their specific methods of locomotion.
Xinyi Yang is a PhD student in the School of Mathematics and Statistics at the University of Melbourne. Her research focuses on modelling the navigation of microswimmers under the influence of fluid flows, external fields, and confinement.
Matthew Walker is a PhD student working in non-Newtonian fluid dynamics (co-supervised by Dr. Edward Hinton and Dr. Jesse Collis). He is particularly interested in applying these flows to geophysical problems and investigating how rheological intricacies govern the movement of lava, mud and concrete.
Number of posts found: 42