Insights into antibiotic resistance promoted by quinolone exposure.

Quinolone-induced antibiotic resistance (QIAR) refers to the phenomenon by which bacteria exposed to sublethal levels of quinolones acquire resistance to non-quinolone antibiotics. We have explored this in MG1655 using a variety of compounds and bacteria carrying a quinolone-resistance mutation in gyrase, mutations affecting the SOS response, and mutations in error-prone polymerases. The nature of the antibiotic-resistance mutations was determined by whole-genome sequencing.

Sll1252 Coordinates Electron Transport between Plastoquinone and Cytochrome Complex in PCC 6803.

A mutant, Δ, was generated to functionally characterize Sll1252. Δ exhibited a slow-growth phenotype at 70 µmol photons m s and glucose sensitivity. In Δ, the rate of PSII activity was not affected, whereas the whole chain electron transport activity was reduced by 45%.

Pseudomonas syringae addresses distinct environmental challenges during plant infection through the coordinated deployment of polysaccharides.

Prior to infection, phytopathogenic bacteria face a challenging environment on the plant surface, where they are exposed to nutrient starvation and abiotic stresses. Pathways enabling surface adhesion, stress tolerance, and epiphytic survival are important for successful plant pathogenesis. Understanding the roles and regulation of these pathways is therefore crucial to fully understand bacterial plant infections.

Comparative genome analysis of Kh10-101 reveals insights into adaptive mechanisms for halo-alkali tolerance.

Unlabelled: is a halo-alkaliphile with optimal growth at pH 10 and 5% NaCl. Phylogenetic analysis revealed habitat-dependent segregation of , with all the alkalihalophiles forming a separate clade. It uses acidification of the external medium and pH-dependent cell wall reinforcement to survive sodic environments.

Characterization of the transient fluorescence wave phenomenon that occurs during H2 production in Chlamydomonas reinhardtii.

The redox state of the plastoquinone (PQ) pool in sulfur-deprived, H2-producing Chlamydomonas reinhardtii cells was studied using single flash-induced variable fluorescence decay kinetics. During H2 production, the fluorescence decay kinetics exhibited an unusual post-illumination rise of variable fluorescence, giving a wave-like appearance. The wave showed the transient fluorescence minimum at ~60 ms after the flash, followed by a rise, reaching the transient fluorescence maximum at ~1 s after the flash, before decaying back to the initial fluorescence level.

The Ssl2245-Sll1130 Toxin-Antitoxin System Mediates Heat-induced Programmed Cell Death in sp. PCC6803.

Two putative heat-responsive genes, and , constitute an operon that also has characteristics of a toxin-antitoxin system, thus joining several enigmatic features. Closely related orthologs of Ssl2245 and Sll1130 exist in widely different bacteria, which thrive under environments with large fluctuations in temperature and salinity, among which some are thermo-epilithic biofilm-forming cyanobacteria. Transcriptome analyses revealed that the clustered regularly interspaced short palindromic repeats (CRISPR) genes as well as several hypothetical genes were commonly up-regulated in Δ and Δ mutants.

Draft genome sequence of Bacillus okhensis Kh10-101T, a halo-alkali tolerant bacterium from Indian saltpan.

We report the 4.86-Mb draft genome sequence of Bacillus okhensis strain Kh10-101T, a halo-alkali tolerant rod shaped bacterium isolated from a salt pan near port of Okha, India. This bacterium is a potential model to study the molecular response of bacteria to salt as well as alkaline stress, as it thrives under both high salt and high pH conditions.

A novel transcriptional regulator, Sll1130, negatively regulates heat-responsive genes in Synechocystis sp. PCC6803.

A conserved hypothetical protein, Sll1130, is a novel transcription factor that regulates the expression of major heat-responsive genes in Synechocystis sp. PCC6803. Synechocystis exhibited an increased thermotolerance due to disruption of sll1130.

RNA helicase, CrhR is indispensable for the energy redistribution and the regulation of photosystem stoichiometry at low temperature in Synechocystis sp. PCC6803.

We investigated the role of a cold-inducible and redox-regulated RNA helicase, CrhR, in the energy redistribution and adjustment of stoichiometry between photosystem I (PSI) and photosystem II (PSII), at low temperature in Synechocystis sp. PCC 6803. The results suggest that during low temperature incubation, i.

An RNA helicase, CrhR, regulates the low-temperature-inducible expression of heat-shock genes groES, groEL1 and groEL2 in Synechocystis sp. PCC 6803.

The crhR gene for RNA helicase, CrhR, was one of the most highly induced genes when the cyanobacterium Synechocystis sp. PCC 6803 was exposed to a downward shift in ambient temperature. Although CrhR may be involved in the acclimatization of cyanobacterial cells to low-temperature environments, its functional role during the acclimatization is not known.