The researchers grew these bacteria on chitin surfaces that simulated their natural habitat on crustaceans. What they found was that the tiny spear is not only part of V. cholerae’s natural survival system, but it also contributed to the transfer of genes that could make the bacterium more resistant to threats, even to antibiotics. The researchers then used genetic and bioimaging techniques to identify, in real time, which mechanisms are involved in this event, which is called “horizontal gene transfer”.
“Using this mode of DNA acquisition, a single V. cholerae cell can absorb fragments containing more than 40 genes from another bacterium,” says Melanie Blokesch. “That’s an enormous amount of new genetic information.” This phenomenon is referred to as “horizontal” gene transfer, as opposed to the conventional “vertical” passage of genes from parent to offspring.
The importance of this study lies in the fact that horizontal gene transfer is a widespread phenomenon in bacteria, and it contributes to the dispersal of virulence factors and antibiotic resistances. In addition, the chitin-mediated activation of the spear-killing device most likely renders the bacterium more dangerous to patients when they ingest it, as this molecular spear might also kill protective bacteria in the human gut. More.
Antibiotic resistance has been widely touted in pop science and schools as proof positive of the Darwinian mechanism of evolution, but it might turn out to be only a secondary one. See also: Bacteria develop antibiotic resistance by using DNA from dead bax . And “Antibiotic-resistant bacteria cut off from the outside world for more than four million years have been found in a deep cave. They were taking part in a read-and-discuss circle on Origin of Species, as part of Science Fiction 201. 😉
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Hat tip: Timothy Kershner