Bacteria Use Liquid Protein Droplets to Overcome Stress, According to Scientists

Bacteria produce small liquid droplets from proteins to help them withstand severe settings and so minimize their chances of being killed by antibiotics, according to scientists. The research shows how aggresomes, which are tiny liquid droplets made up of several distinct proteins, develop in response to increased stress in bacteria, and that these bacteria may generate aggresomes that are better able to withstand these pressures.

Bacteria are divided into five types based on their fundamental shapes: spherical (cocci), rod (bacilli), spiral (spirilla), comma (vibrios), and corkscrew (spirochaetes). They might be single cells, pairs of cells, chains, or clusters. Bacteria may be found in many types of environments on Earth, including soil, rock, seas, and even polar snow. Some creatures, including plants and animals, including humans, live in or on other organisms. In the human body, there are around ten times as many bacterial cells as there are human cells.

Example of liquid protein droplets

A suspension of protein in a fluid, such as water, is known as liquid protein. Liquid protein may be used in a variety of ways, and it is widely accessible in health food stores, drug stores, grocery stores, and places that sell bodybuilding gear. Vitamins and minerals are generally included in liquid protein to offer a balanced nutritional composition to the user.

Our study shows that aggresomes in bacteria are highly dynamic structures; they are what we would describe as ‘cell organelles,’ but they lack the sort of membrane on the outside that we would usually find in better-studied organelles, such as the nucleus inside our own cells.

Mark Leake

Environmental pressures were connected to lower levels of ATP, the “universal currency of cell energy,” in bacteria, according to the research team, which was lead by experts from the University of York and Peking University. This decrease in solubility of critical cellular proteins is likely to have influenced their ability to assemble into droplets.

The findings might shed light on how some bacteria can both survive lengthy antibiotic treatments and, by modifying their DNA, boost their chances of developing total resistance to antibiotics.

The researchers demonstrated that droplet formation is described by the physics of “liquid-liquid phase separation” utilizing enhanced optical microscopy and computer modeling.

According to scientists, the forces of attraction between molecules in solution cause them to form semi-stable assemblies with fascinating liquid characteristics, which can contain hundreds of molecules of various proteins in the case of aggresomes. Molecules within an aggresome are free to move about as if they were in a liquid, and they can interact with molecules outside the aggresome.

Bacteria effectively store proteins that are crucial to fundamental cellular operations in droplets during stress as the cell shuts down, keeping them safe until the detrimental environment recedes while assisting the cell’s recovery.

Co-lead author of the study, Professor Mark Leake, from the Department of Physics and Department of Biology at the University of York, said: “Our study shows that aggresomes in bacteria are highly dynamic structures; they are what we would describe as ‘cell organelles,’ but they lack the sort of membrane on the outside that we would usually find in better-studied organelles, such as the nucleus inside our own cells.”

“Relying on more fixed structures like membrane-bound organelles is too slow: they don’t allow bacteria to respond fast enough to a rapidly changing environment since it takes time to make and break a membrane and to select which molecular components are allowed to enter and exit. Aggresomes get around this by not having a membrane at all. Instead, bacteria have wonderfully modified the fundamental physics of phase separation in liquids to aid their survival.”

The study involved an international team of academics from a variety of fields, including biophysics, microbiology, genetics, mathematics, and computer science.

The researchers put fluorescent tags on aggresome protein molecules to track their whereabouts in E. coli bacterium live cells, which are identical to those found in our stomachs. They used math modeling and computer simulations to figure out how the creation of highly dynamic protein droplets is caused by liquid-liquid phase separation.

Prof Leake added: “The only way we could gain this new understanding is through a large team with expertise that spans multiple disciplines, using advances in experimental biophysics from my team, innovative theoretical approaches from the team of Tom McLeish in York, and state-of-the-art bacterial genetics from Fan Bai’s group in Beijing.”

“Research into understanding the workings of these remarkable biological liquid droplets at the scale of single molecules as we have done here may help us to understand why things go wrong in the case of some diseases, not only caused by bacteria but also in conditions of the immune system and in dementia that appear to involve droplet-like molecular assemblies. It might open the path for novel medications that either prevent or target the formation of certain droplets.”