bacterial intelligence: prexisting protections (Animals)

by David Turell , Wednesday, May 31, 2017, 20:18 (2731 days ago) @ David Turell

Mycobacteria cause TB. They also contain defense mechanisms in some individuals that can help them survive our antibacterials:

https://phys.org/news/2017-05-mycobacteria-protein-diverse-populations-drugs.html

"Subgroups of tuberculosis (TB)-causing bacteria can persist even when antibiotics wipe out most of the overall population. The need to eliminate these persistent subpopulations is one reason why TB treatment regimens are so lengthy. Now, researchers have shown that a single protein allows mycobacteria to generate diverse populations that can avoid TB drugs. The protein may be a target for intervention; blocking it might result in less mycobacterial diversity and shorten TB treatment courses.

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"Using fluorescent reporter molecules and time-lapse microscopy, they examined individual cells as they grew and divided. Mycobacteria can generate daughter cells through asymmetric growth, resulting in genetically identical, but physiologically diverse, populations. The mechanisms underlying this ability and the extent to which the cells' size, growth rate and other physiological properties relate to survival in mycobacterial populations were not well understood.

"Dr. Rubin and colleagues determined that the protein product of a single gene, lamA, is a member of the protein machinery that is active when mycobacteria divide. The protein—which is not known to exist in other rod-shaped bacteria or other organisms—seems to allow for asymmetrical growth in new mycobacterial cells made during cell division. The asymmetrical growth leads to bacteria with wide variations in physiological properties and susceptibility to antibiotics.

"In experiments using Mtb, the scientists found that mycobacteria without lamA formed far less diverse bacteria with more uniform susceptibility to antibiotics. When exposed to the front-line TB drug rifampicin, for example, Mtb cells lacking lamA were less able to survive than wildtype bacteria."

Comment: Here we see a gene which directly creates variability in daughters, some of which have the ability to fight off an antibiotic. This is all automatic in its reproduction. No intelligence involved.