Dr Sasha Tetu is a Senior Lecturer in the Department of Molecular Sciences at Macquarie University. Sasha obtained her PhD from the University of Sydney for research into the interactions of different mobile genetic elements within bacterial genomes. Following this she worked as a postdoctoral researcher with Prof Ian Paulsen here at Macquarie University, applying molecular microbiology and ‘omics techniques to microorganisms involved in disease, industrial and agricultural processes. This was followed by an ARC DECRA fellowship (finished in 2020) investigating how anthropogenic pollutants affect marine bacteria, from population and phenotypic changes, down to changes in gene expression.

Sasha’s current research efforts focus on understanding the genetic basis for microbial adaptation to environmental pressures and how environmental perturbations impact microbial communities. She is particularly interested in how mobile genetic elements contribute to niche adaptation in bacteria. 

Dr Tetu would love to hear from motivated students keen to join her Applied and Environmental Microbiology research group.

Projects currently underway include:

Investigating the impact of human pollutants on key marine microbes

Bacterial primary producers underpin marine food webs and are critical to biogeochemical cycling in the ocean. However, despite their importance, they are often not considered in pollution threat assessment. We are working to address this knowledge gap, with a number of projects underway looking at how key marine photosynthetic bacteria are affected by anthropogenic pollutants, such as chemicals leached from plastic litter.

This research applies culture-based microbiology and molecular biology techniques to look at how different chemicals affect the growth, physiology and gene expression of these important marine microbes. Techniques used in this work include flow cytometry, photophysiology measurements, metagenomics and transcriptomics. Work to date has led to widely acclaimed publications (eg https://www.nature.com/articles/s42003-019-0410-x, covered by >40 news outlets around the world).

For more information on this work please also check out our recent review (https://www.nature.com/articles/s42003-020-0789-4)

Origins and spread of integron gene cassettes (together with Prof Michael Gillings)

Integrons and their associated gene cassettes are mobile genetic elements capable of transferring genetic information across a wide range of bacteria, including between distantly related taxa. They are best known for their role in spreading antibiotic resistance genes among pathogens. In addition to their clinical significance there is good evidence they contribute to broader niche adaptation in many bacterial species.

In this ARC funded project, we are setting out to address key outstanding questions in integron biology. How are integron gene cassettes generated and in which taxa does this occur?  What range of traits are encoded in gene cassettes?  This research involves applying a suite of molecular microbiology tools and bioinformatic analyses to samples from a diverse array of environments. Understanding cassette origins is key to controlling their activity, both to prevent pathogens from acquiring new, dangerous traits and in investigating potential beneficial biotechnological applications.

For more information please see our recent review (Ghaley et al 2020 https://www.sciencedirect.com/science/article/pii/S0966842X19303178?via%3Dihub)