Killer bacteria discovered: How they suck out neighboring cells!

Killer bacteria discovered: How they suck out neighboring cells!

Swiss researchers at ETH Zurich and Eawag have made significant progress in understanding rod-shaped Vibrio bacteria. These bacteria are able to kill and suck out their neighboring cells through a sophisticated system known as the type 6 secretion system (T6SS). Loud oe24 The T6SS works like a spear with a poisonous tip that is fired into neighboring cells.

An interesting discovery is the variation in the toxins these killer cells use. Depending on their diet, they can load their spears differently. When the killer cells are starved, they empty the prey cells more slowly to absorb more nutrients. This process can take up to 90 minutes. In contrast, well-supplied cell types lead to faster dissolution of the victim cells, which only takes about 20 minutes.

Insights into the type 6 secretion system

The type 6 secretion system is a bacterial secretion system that is primarily used by gram-negative bacteria to transport effectors into neighboring cells. Studies show that at least 25% of all pathogenic and non-pathogenic Proteobacteria species have genes encoding the T6SS, as shown on Wikipedia is reported. It was discovered in connection with Vibrio cholerae in 2006, with initial evidence of T6SS gene products in Edwardsiella tarda being published as early as 2004.

The structure of this system resembles an inverted phage and consists of 14 proteins arranged into three subcomplexes: a phage-like tubule, a base plate, and a membrane complex. The tubule can be up to 600 nm long and consists of repeating units. The contraction of the tubule is crucial because it drives the effectors from the bacterial cell into the neighboring cell.

Importance for ecosystems

Analysis of DNA sequence databases shows that Vibrio bacteria often lack genes for the metabolism of complex carbohydrates. This suggests that these killer bacteria are genetically optimized to thrive on easily usable molecules, such as cell sap. Interestingly, the highest proportion of T6SS-positive bacteria were found around plant roots in the soil, suggesting an important role in nutrient cycling of ecosystems.
As the authors reported in the journal Science, the behavior of these bacteria could have far-reaching implications for understanding interbacterial antagonism and ecological nutrient cycling.

In summary, the research on T6SS provides insights not only into how these bacteria function, but also into their potential role in the environment, reinforced by the findings also on Wikipedia are held. These studies expand our knowledge of bacterial interactions and their effects on various ecosystems worldwide.