A Round Up of Latest Research News from Macquarie University

Trillions of microbes live in our digestive systems, impacting everything from our immune response to our brain health. Microbiologist Dr Hasinika Gamage explains how you can get better acquainted with your gut microbiome.

Your digestive system, or gut, is home to thousands of microbial species that together form what's known as the gut microbiome. These microscopic residents aren't just passive hitchhikers – they play vital roles in keeping you healthy.

1. Your gut is teeming with life

The gut microbiome consists of trillions of microorganisms, primarily bacteria, but also fungi, viruses and other microscopic life forms. Together, they form a complex ecosystem that helps your body function properly.

"These microbes and the substances they produce help us digest our food, absorb energy and nutrients, support our immune system and even keep our brain healthy," says Dr Gamage. "Our diet, lifestyle and overall health play a big role in how our gut microbiome is made up."

2. Your gut talks to your brain

There's a communication pathway between your gut and your brain, often called the gut-brain axis. Information travels via a nerve connection called the vagus nerve and through chemical messengers produced by gut bacteria carried to your brain through the bloodstream.

"In certain neurodegenerative diseases, such as Machado-Joseph disease, we have observed that microbial changes occur before any symptoms appear," says Dr Gamage. "We also know that the extent of the microbiome change is linked to how severe the symptoms are."

3. Most probiotics don't survive the journey through the stomach

You've probably seen probiotics – supplements that contain beneficial live bacteria – in the pharmacy or supermarket. These products are meant to boost gut health, but after passing through the highly-acid stomach area, many don't reach your intestines alive.

"That acidic, low pH kills a lot of bacteria," says Dr Gamage. "There are also bile salts in the small intestine that our body uses to digest fat. Because the cell structure of bacteria is also made of lipids, or fats, they are attacked by these bile salts, too."

4. Different fibres feed different microbes

Prebiotics – dietary fibres that feed beneficial gut bacteria – are another common approach to improving gut health. However, not all prebiotics work the same way or benefit the same bacteria.

"We still don't have a clear understanding of what prebiotics to use for which condition," says Dr Gamage.

5. Your microbiome is as unique as your fingerprint

While humans all share similar types of gut bacteria, the specific composition of your microbiome is highly individual. It's influenced by factors including your genetics, diet, lifestyle, environment, medication use, and even experiences from early life such as your mode of delivery and infant feeding.

"Current methods, which use probiotics and dietary fibres, actually work best as personalised medicine that is targeted to an individual's microbiome," says Dr Gamage.

Article in Lighthouse: https://lighthouse.mq.edu.au/article/april-2025/please-explain-five-surprising-things-about-your-gut-microbiome

Research: Pereira, J.V.; Gamage, H.K.A.H.; Cain, A.K.; Hayes, E.; Paulsen, I.T.; Tetu, S.G. High-Throughput Viability Testing of Microbial Communities in a Probiotic Product Using Flow Cytometry. Appl. Microbiol. 2023, 3, 1068-1082. https://doi.org/10.3390/applmicrobiol3030

Ancient Antarctic mountains revealed

Australian researchers have discovered how a large mountain chain resembling the European Alps and buried deep below the East Antarctic ice sheet, grew and partly collapsed more than half a billion years ago.

Formed by an ancient collision of two continents, the Gamburtsev Subglacial Mountains are central to Earth's tectonic history and the assembly of the supercontinent Gondwana.

A new study revealing the roots of these ancient mountains, by metamorphic petrologist at Macquarie University, Professor Nathan Daczko and ACEAS Chief Investigator and geologist at UTAS' Institute of Marine and Antarctic Studies Associate Professor Jacqueline Halpin, is published in scientific journal, Earth and Planetary Science Letters and linked to the ACEAS/Australian-led Denman Terrestrial Campaign (DTC).

It estimates the continental collision occurred between 500 and 650 million years ago, driving up the mountain range with such force, the deeper crust beneath heated and flowed sideways – almost like toothpaste squeezed from a tube.

Known as gravitational spreading, this process spread out hot viscous and partly molten rock from the core of the mountains for up to a thousand kilometres – and would lead to the partial collapse of the range.

"This research is highly significant because it provides a new tectonic model that links rare coastal outcrops to the ice-covered interior of East Antarctica, and helps us understand the architecture of a half a billion-year-old collision zone of the same scale as the modern Himalayan mountain chain," said Professor Daczko.

"This new interpretation brings together many previous studies over a vast area of East Antarctica providing a unified model to guide future exploration and research."

With most of East Antarctica buried under ice, the researchers turned to zircon crystals, collected from sedimentary rock outcrops in the Prince Charles Mountains. Eroded from the collision area and transported downstream where they were deposited more than 250 million years ago, they serve as time capsules of the mountain-building event said Associate Professor Halpin.

"Zircon is special in that it contains tiny amounts of radiogenic isotopes that decay at known rates. By analysing the ratio of these isotopes, we calculate their crystallisation age and derive a signature of their tectonic environment," she said.

"Most of the Antarctic continent is hidden beneath thick ice, but the geology underneath helps control how the ice sheet behaves," Associate Professor Halpin said.

"This research improves our understanding of the crustal architecture of East Antarctica including how topographic patterns are controlled, and how natural heat from the bedrock is distributed, which affects the flow of the ice."

Research: Nathan R. Daczko, Jacqueline A. Halpin, Gondwanan continental collision drives gravitational spreading and collapse of the ancestral East Antarctic mountains, Earth and Planetary Science Letters, Volume 662, 2025, 119394, ISSN 0012-821X, https://doi.org/10.1016/j.epsl.2025.119394 .

Eureka! The global warming maths problem that took 15 years to solve, by Fran Molloy, Macquarie University, Faculty of Science & Engineering.

In solving the complex maths to calculate how irregular atmospheric particles affect global warming, a Macquarie University mathematician has built equations that could improve climate modelling, medical imaging and material design.

Tiny particles high in our atmosphere play a key role in our climate, but deciphering the mathematics to calculate their impact on global warming has been a 15-year labour of love for Macquarie University mathematician Associate Professor Stuart Hawkins.

When microscopic particles - like mineral dust, or soot from fires - drift into the upper atmosphere, they change how the sun's light reaches the Earth below. But because each particle has a unique, irregular shape, it's extremely difficult to determine their overall impact.

"These particles might cool the Earth by reflecting light back into space, or warm it by reflecting light to the ground or warm the surrounding air by absorbing the light," says Associate Professor Hawkins, a lecturer in computational mathematics at Macquarie University's School of Mathematical and Physical Sciences.

"Scientists couldn't accurately calculate their effect because the mathematical tools available only worked well for nearly spherical particles; but these particles are mostly not spherical."

Associate Professor Hawkins first learned of this conundrum in 2008, when the atmospheric physicist, Associate Professor Michael Box, told a lecture audience that without a suitable model to show the effect of these particles, the calculations predicting how the climate would behave in future had a significant gap.

In a new paper published in the Journal of Quantitative Spectroscopy and Radiative Transfer, Associate Professor Hawkins and his collaborators have unveiled an elegant solution: a method to accurately calculate how light scatters off irregularly shaped particles, including long, thin particles – something previous methods couldn't achieve.

Their calculations remain accurate even for particles 15 times longer than they are wide, far exceeding what current methods can handle.

"Scientists have been able to solve the equations for spherical particles for about 100 years," says Associate Professor Hawkins. "However, critical particles such as the minerals that originate in Australia's deserts and end up in the atmosphere are non-spherical, so we could not accurately simulate light scattering from this important family of particles."

Associate Professor Hawkins has also created a clever open-access computer program to smooth the way, called T-Mat Solver.

"Previously, scientists had to assume these particles were close to spherical, which most are not. Now we can work with differently shaped spheroids, or average results over a range of random-shaped particles."

Article in Lighthouse: https://lighthouse.mq.edu.au/article/may-2025/eureka!-the-global-warming-maths-problem-that-took-15-years-to-solve

Research: M. Ganesh, Stuart C. Hawkins, T-matrix computations for light scattering by penetrable particles with large aspect ratios, Journal of Quantitative Spectroscopy and Radiative Transfer, Volume 334, 2025, 109346, ISSN 0022-4073, https://doi.org/10.1016/j.jqsrt.2025.109346 .

Why biology could be the future of computing and engineering, by Mary O'Malley.

A new paper from Macquarie University scientists outlines how engineered biological systems could solve limitations in traditional computing, as international competition accelerates development of 'semisynbio' technologies.

Australian researchers are turning to nature for the next computing revolution, harnessing living cells and biological systems as potential replacements for traditional silicon chips.

Living computers, organs-on-a-chip, data storage in DNA and biosecurity networks that detect threats before they spread – these aren't science fiction concepts but emerging realities. A team from Macquarie University and the ARC Centre of Excellence in Synthetic Biology (COESB) has explored this convergence of biological and digital technologies in a paper published in Nature Communications.

The Macquarie University authors—Professor Isak Pretorius, Professor Ian Paulsen and Dr Thom Dixon (who are also affiliated with the ARC Centre of Excellence in Synthetic Biology), Professor Daniel Johnson and Professor Michael Boers—draw on decades of combined experience to explain why harnessing bio-innovation can proactively shape the future of computing technology.

"As biology and digital technology merge, we're entering an era of bio-inspired computing and engineering that could redefine the future of innovation," says Professor Pretorius.

The global economy relies on information and energy flows, and the race for computer science to develop artificial intelligence that can attempt to handle these flows, comes at an enormous cost in energy and resources. Meanwhile, over 3.5 billion years of evolution, nature has become very good at efficiently sensing, solving problems and making decisions.

Biological systems have inspired breakthroughs like brain-computer interfaces and 'neuromorphic chips' - processors designed to mimic the brain. A key milestone in this field is the recent mapping of a fruit fly's entire neural network.

With silicon chips reaching their limits, scientists are turning to biological intelligence as a way forward. Cellular computing, liquid computing, and DNA data storage could work alongside traditional chips, unlocking new efficiencies.

"Rather than forcing biology to fit into digital systems, we should learn from nature's intelligent designs," says Professor Paulsen. "Integrating biological computing with technology could revolutionise AI, sensing, and data processing, leading to a more sustainable future."

"The age of semisynbio is upon us, and its potential is bound only by human imagination," says Professor Pretorius.

Article in Lighthouse: https://lighthouse.mq.edu.au/article/june-2025/why-biology-could-be-the-future-of-computing-and-engineering

Research: Pretorius, I.S., Dixon, T.A., Boers, M. et al. The coming wave of confluent biosynthetic, bioinformational and bioengineering technologies. Nat Commun 16, 2959 (2025). https://doi.org/10.1038/s41467-025-58030-y

Cannabis extract shows promise to treat fungal infections, by Bianca Nogrady.

Macquarie University research found compounds derived from the cannabis plant can effectively combat fungal infections including athlete's foot and the deadly Cryptococcosis, raising hope for the development of new topical treatments.

In a study published in The Journal of Neglected Tropical Diseases (PLOS NTDs), bioactives Cannabidiol (CBD) and Cannabidivarin (CBDV) were shown to kill harmful Cryptococcus neoformans - a WHO-listed priority fungal pathogen. The compounds also killed dermatophytes causing common skin infections faster than existing treatments.

Fungal infections affect over billion people globally each year, according to data from the Centres for Disease Control and Prevention. Fungal pathogens are a serious health threat with relatively few effective treatments.

Postdoctoral research fellow Dr Hue Dinh and Associate Professor Amy Cain in Macquarie University's School of Natural Sciences resolved to tackle the growing threat of fungal infections with help from Professor Mark Connor and Dr Marina Junqueira Santiago from the Macquarie School of Medicine and collaborators at the Universities of Sydney and NSW.

The researchers found two cannabinoids – cannabidiol and cannabidivarin – that both quickly killed Cryptococcus neoformans in the laboratory, working even faster than current antifungal therapy.

"When Cryptococcus neoformans gets to your central nervous system, it causes life-threatening meningitis. The mortality rate is very high, and it's really hard to treat," says Dr Dinh.

Testing the compounds against 33 other fungal pathogens from clinical, veterinary and environmental settings they found the cannabinoids killed a range of Cryptococcus species, and the fungal skin pathogens causing athlete's foot.

The final part of the study confirmed the cannabinoids could treat a fungal infection in a living organism – the Galleria mellonella (wax moth) larvae.

Dr Dinh and Associate Professor Cain are now working with commercial partners to develop a product for over-the-counter use. "If we can demonstrate that these ones work well for common infections, you could actually just get some CBD oil and then rub it on your skin to treat it."

Article in Lighthouse: https://lighthouse.mq.edu.au/article/may-2025/cannabis-extract-shows-promise-as-treatment-for-fungal-infections

Research: Dinh H, Fernandes KE, Erpf PE, Clay EJM, Tay AP, Nagy SS, et al. (2025) Uncovering the antifungal potential of Cannabidiol and Cannabidivarin. PLoS Negl Trop Dis 19(6): e0013081. https://doi.org/10.1371/journal.pntd.0013081