Cell population heterogeneity during growth of Bacillus subtilis

Abstract

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The predatory life cycle of Myxococcus xanthus

“…Fruitingbody maturation in Myx. xanthus is one of several examples of population bifurcation in bacteria (Kearns & Losick, 2005). Fruiting-body formation allows part of the population of Myx.…”

Variability in β-catenin pulse dynamics in a stochastic cell fate decision inC. elegans

“…This small portion of the population, called "persisters", stochastically arises from the adoption of a different set of expression levels in genes that control a toxin and anti-toxin, effectively becoming "trapped" in a quiescent yet antibiotic-resistant state. These results indicate that noisy gene expression is a sufficient mechanism to produce the bimodality that leads to different stochastic cell fates (Kearns and Losick, 2005;Losick and Desplan, 2008).…”

SwrAA activates poly-γ-glutamate synthesis in addition to swarming in Bacillus subtilis

“…However, it can be excluded that the role of DegU~P is limited to the induction of swrAA expression, since SwrAA overexpression in a degU + strain had no effect on c-PGA production, as reported above. The molecular role played by SwrAA is still unclear, although in transcriptional profiling assays SwrAA was found to enhance transcription of the motility and chemotaxis operon fla/che acting on P fla/che(A) (Kearns & Losick, 2005). If this was the exclusive role played by SwrAA, then a gene(s) belonging to the fla/che operon including sigD, or a s D -dependent gene, had to be responsible for c-PGA production.…”

“…Laboratory strains carry a single nucleotide insertion in the coding region of swrAA leading to premature product truncation (swrAA 2 ) (Kearns et al, 2004). In a laboratory strain, complementation experiments with a wild-type (wt) copy of the gene resulted in a significant improvement in both swimming capacity and ability to swarm on semi-solid surfaces treated with surfactin (Calvio et al, 2005(Calvio et al, , 2008, biasing cells into a s D -ON state (Kearns & Losick, 2005). The swrAA 2 motility phenotype could be suppressed by a fla/che promoter upmutation, and microarray experiments indicated that SwrAA enhances expression of the fla/che operon, acting on the s A -dependent promoter P fla/che(A) (Kearns & Losick, 2005).…”

“…In a laboratory strain, complementation experiments with a wild-type (wt) copy of the gene resulted in a significant improvement in both swimming capacity and ability to swarm on semi-solid surfaces treated with surfactin (Calvio et al, 2005(Calvio et al, , 2008, biasing cells into a s D -ON state (Kearns & Losick, 2005). The swrAA 2 motility phenotype could be suppressed by a fla/che promoter upmutation, and microarray experiments indicated that SwrAA enhances expression of the fla/che operon, acting on the s A -dependent promoter P fla/che(A) (Kearns & Losick, 2005). Several lines of evidence point to a cooperation between SwrAA and DegU~P in motility (Kobayashi, 2007;Verhamme et al, 2007;Calvio et al, 2008) and here we demonstrate not only that the two proteins must cooperate to drive c-PGA production, but also that such an effect is achieved independently of the activation of the fla/che promoter.…”