Annual review of persisters cells part dwa

– The other gene is yigB. It’s a phosphatase of flavin mononucleotide. Similair to ygfA overexpressing this gene leads to depletion of FMN. A blast shows no good match to HI

– A method of isolating persisters. Adding an antibiotic is undesirable for many studies because the lysing cells may alter the persister phenotype. Since persisters are thought to have lower protein production you can use degradable GFP and identify persisters by looking at dim colonies. Interesting. Maybe I could also put a degradable fluorescent marker on Sxy expression and check to see when cells enter competency that way.

– Toxin/Antitoxins modules are up regulated under persistance. A review

The toxin is stable and inhibits some cellular process, the antitoxin is degradable. Sometimes the module is found on plasmids and results in the death of all daughter cells who do not inherit a copy of the plasmid. Commonly they’re found on chromosomes and the function there is unknown.

The post doc recommended a good paper to read on TA modules. The gist is that they surveyed almost 400 islates of ecoli for the chromsomal TA module ccdO157 . They found evidence that it’s under neutral selection has no adaptive function. Wierdly the region where ccdO157 usually resides in, the Fola Apah intergenic region,  is a hotspot for exogenous mobile genetic element integration. No explanation why(read about REPs for more info)!

Chromosomal TA systems are sometimes induced under stress conditions, ala mazEF and relBE, but there is no solid evidence that they help the bacteria in any way.

Additionally TA systems are part of genomic islands, dissemniating through horizontal gene transfer? I don’t know much about this.

Some toxins induce stasis, by degrading mRNA. Knockout of single TA modules don’t have an effect on persistence however, but that could be due to redundancy – Ecoli has 15 modules while tuberculosis has 80

It’s taking me along time tog et through this review. Every new topic that comes up I have to stop and read up about it in more depth. I’ll have a third part to finish up, it will include the role of SOS tisB toxic protein(no HI homolog), a clss of antibiotics that induce multi drug tolerance, and noise

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