Arsenobetaine: an ecophysiologically important organoarsenical confers cytoprotection against osmotic stress and growth temperature extremes.

Arsenic, a highly cytotoxic and cancerogenic metalloid, is brought into the biosphere through geochemical sources and anthropogenic activities. A global biogeochemical arsenic biotransformation cycle exists in which inorganic arsenic species are transformed into organoarsenicals, which are subsequently mineralized again into inorganic arsenic compounds. Microorganisms contribute to this biotransformation process greatly and one of the organoarsenicals synthesized and degraded in this cycle is arsenobetaine.

Genetic control of osmoadaptive glycine betaine synthesis in Bacillus subtilis through the choline-sensing and glycine betaine-responsive GbsR repressor.

Synthesis of the compatible solute glycine betaine confers a considerable degree of osmotic stress tolerance to Bacillus subtilis. This osmoprotectant is produced through the uptake of the precursor choline via the osmotically inducible OpuB and OpuC ABC transporters and a subsequent two-step oxidation process by the GbsB and GbsA enzymes. We characterized a regulatory protein, GbsR, controlling the transcription of both the structural genes for the glycine betaine biosynthetic enzymes (gbsAB) and those for the choline-specific OpuB transporter (opuB) but not of that for the promiscuous OpuC transporter.

Regulated secretion of a protease activates intercellular signaling during fruiting body formation in M. xanthus.

In response to starvation Myxococcus xanthus initiates a developmental program that culminates in fruiting body formation. There are two morphogenetic events in this program, aggregation and sporulation, which are temporally and spatially coordinated by the contact-dependent intercellular C-signal protein (p17). p17 is generated by proteolytic cleavage of the p25 precursor protein, which accumulates in the outer membrane of vegetative and starving cells.

The Aspergillus nidulans putative kinase, KfsA (kinase for septation), plays a role in septation and is required for efficient asexual spore formation.

In Aspergillus nidulans nuclear division and cytokinesis are coupled processes during asexual sporulation. Metulae, phialides and conidia contain a single nucleus. Here we describe the role of a putative Saccharomyces cerevisiae Kin4-related kinase, KfsA (kinase for septation) in the control of septum formation in A.