Researchers at Karolinska Institutet, Umeå University, and the University of Bonn have identified a new group of molecules that have an antibacterial effect against many antibiotic-resistant bacteria. Since the properties of the molecules can easily be altered chemically, the hope is to dev ... more
Membrane vesicles released by bacteria may play different roles during infection
Bacteria release membrane-derived vesicles (MVs), which are small particles that can transport virulence factors to neighbouring bacteria or to the cells of a mammalian host. This special MV-based system for delivering toxic proteins and nucleic acids in a protected manner to the target cells may have different specific functions depending on whether the bacterium acts as an extracellular or intracellular pathogen. This is according to a doctoral thesis from Umeå University in Sweden.
Together with her research colleagues and in collaborations, doctoral student Svitlana Vdovikova showed that MVs can have varying functions by using two different pathogenic bacteria as examples: Vibrio cholerae and Listeria monocytogenes. Vibrio cholerae causes cholera, a disease taking thousands of lives each year in developing countries. Listeria monocytogenes causes listeriosis, which leads to a deadly infection in one third of the cases and is especially dangerous for pregnant women and their fetuses, newborn children, and immunocompromised people.
The researchers found that MVs from both Vibrio cholerae and Listeria monocytogenes transport so-called pore-forming toxins (PFTs). These proteins usually cause a range of toxic effects on the targeted human cells due to the formation of pores in cell membranes.
"Pore-forming toxin delivered by Vibrio cholerae MVs activate autophagy, which serves as a cellular defence mechanism. In contrast, we found that the pore-forming toxin transported by membrane vesicles of Listeria monocytogenes does not trigger autophagy. Moreover, MVs from the Listeria bacterium can protect against the pore formation and autophagy. These findings suggest that MV production might be a relevant strategy of Listeria to manipulate host responses and to promote bacterial survival inside the host cells," says Svitlana Vdovikova, doctoral student at the Department of Molecular Biology.
MVs serve as promising candidates for vaccine development and are used as tools in nanotechnology and for directed drug delivery. For example, a MV-based vaccine against meningitis is already being used in Europe, Australia and the United States. Additionally, bacterial MVs are currently being studied as drug-delivery vehicles for treating various cancer forms.
"These results not only help us to understand more about the mechanisms of different bacterial infections. They also bring new opportunities in medicine and biotechnology, for example, by allowing to therapeutically modulate cell autophagy, a process which plays a central role in cancer, diabetes, cardiovascular and many other diseases," says Svitlana Vdovikova.
- Listeria monocytogenes
- Vibrio cholerae
- virulence factors
- vaccine development
- molecular biology
- bacterial infections
- cell membranes
Chemists at Umeå University have succeeded in mapping structures and functions of a transient enzyme state. By modifying the enzyme adenylate kinase, researchers were able to isolate the molecule and study it using the quantitative techniques X-ray crystallography and nuclear magnetic reson ... more
Persons with the serious disorder ALS, can have a genetic mutation that causes the protein SOD1 to aggregate in motor neurons in the brain and spinal cord. Researchers at Umeå University have discovered that, when injected into mice, the SOD1 aggregation spreads rapidly leading to ALS. ALS, ... more
- 1Elusive carbonic acid: it really exists!
- 2A new tool for estimating people’s total exposure to potentially harmful chemicals is developed by Mount Sinai researchers
- 3Advances in spectroscopy
- 4New Molecular Microscopy Uncovers how Breast Cancer Spreads
- 5Imaging cells: New method enables clear, precise look inside
- 6Smarter sensor sniffs out target gases
- 7Can smartphones predict mortality risk?
- 8SARS-CoV-2 detection in 30 minutes using gene scissors
- 9Fighting tumours with magnetic bacteria
- 10Seeing concentrations of toxins with the naked eye
- Distinguish sugars with eye-catching and stretchy rainbow film
- Neuroscientists illuminate how brain cells deep in the cortex operate in fre ...
- Tomography shows high potential of copper sulphide solid-state batteries
- Sinonasal cancer: AI facilitates breakthrough in diagnostics
- Hope for first blood test to detect deadly heart inflammation
- The Nobel Prize in Physiology or Medicine 2022 goes to Svante Pääbo: What makes us uniquely human?
- Nano-sensor detects pesticides on fruit in minutes
- Scientists solve mystery about catalysis for green production of methanol from carbon dioxide
- New tool reveals function of enigmatic gene sequences
- Method to reveal undesired biological effects of chemicals