Scientists expose fascinating ‘compartments’ in bacteria

Bacteria, small one-celled organisms and, in some cases, deadly, are much more complex than is commonly thought.

A review article from the Monash Biomedicine Discovery Institute (BDI), published in the high-impact journal Nature Reviews Microbiology, sheds light on the organelles, the internal compartments of bacterial cells that house and support essential functions for their survival and growth.

BDI professor Trevor Lithgow and associate professor Chris Greening, experts in bacterial cell biology and physiology, were invited to review the scientific literature available worldwide to consolidate the latest knowledge of organelles.

“There was an ancient truth until recently that bacteria were simply a bag of enzymes, the simplest type of cell,” said Professor Lithgow. “New developments in nanoscale imaging have shown that the internal compartments (organelles) make them very complex.”

Cryoelectron microscopy and super resolution microscopy have allowed scientists to understand the workings of bacterial organelles, which are generally 10,000 times smaller in diameter than a pinhead. BDI has been at the forefront in Australia by adopting and developing the use of these technologies, said Professor Lithgow.

“It has been a rewarding experience to do this academic review and to be able to show the wide range of work that demonstrates the complexity of bacterial cells,” he said.

Organelles allow bacteria to do extraordinary things. They aid the photosynthesis of bacteria in poorly lit environments, break down toxic compounds like rocket fuel, or even target relative to Earth’s magnetic field by aligning magnetic iron particles. Some bacteria use the gas collected within the organelles to control buoyancy and allow them to rise or fall in the water, allowing optimal access to light and nutrients for growth and division.

Exploring and understanding the complexities of bacterial cells is important not only for scientific knowledge, but also for biotechnological applications and for addressing global human health problems.

“Organelles allow many bacteria to perform useful functions for us, from supporting basic ecosystem function to allowing all kinds of biotechnological advancements. But some pathogens use organelles to cause disease,” said associate professor Greening. “The deadly pathogen that causes tuberculosis, for example, removes fat molecules from our own bodies and stores them as energy reserves in the organelles, helping the pathogen to persist for years in our lungs, compromising treatment and making it likely emergence of drug resistance. “

Countering drug-resistant infections are key problems for 21st-century humans, Professor Lithgow said. “In these COVID-19 times, the number of deaths we’re seeing from viral infections is terrible, but the projection is that by 2050 at least 22,000 Australians (and 10 million people worldwide) will die each year from infections caused by drug-resistant bacteria, “he said.