Proteomic Insights into Sulfur Metabolism in the Hydrogen-Producing Hyperthermophilic Archaeon Thermococcus onnurineus NA1.

The hyperthermophilic archaeon Thermococcus onnurineus NA1 has been shown to produce H2 when using CO, formate, or starch as a growth substrate. This strain can also utilize elemental sulfur as a terminal electron acceptor for heterotrophic growth. To gain insight into sulfur metabolism, the proteome of T. onnurineus NA1 cells grown under sulfur culture conditions was quantified and compared with those grown under H2-evolving substrate culture conditions. Using label-free nano-UPLC-MSE-based comparative proteomic analysis, approximately 38.4% of the total identified proteome (589 proteins) was found to be significantly up-regulated (≥1.5-fold) under sulfur culture conditions. Many of these proteins were functionally associated with carbon fixation, Fe-S cluster biogenesis, ATP synthesis, sulfur reduction, protein glycosylation, protein translocation, and formate oxidation. Based on the abundances of the identified proteins in this and other genomic studies, the pathways associated with reductive sulfur metabolism, H2-metabolism, and oxidative stress defense were proposed. The results also revealed markedly lower expression levels of enzymes involved in the sulfur assimilation pathway, as well as cysteine desulfurase, under sulfur culture condition. The present results provide the first global atlas of proteome changes triggered by sulfur, and may facilitate an understanding of how hyperthermophilic archaea adapt to sulfur-rich, extreme environments.

Genome Sequence of Arthrobacter sp. MWB30, Isolated from a Crude Oil-Contaminated Seashore.

We report here the draft genome sequence of Arthrobacter sp. MWB30 strain, isolated from a crude oil-contaminated seashore in Tae-an, South Korea, which is able to degrade the crude oil and its derivatives. The draft genome sequence of 4,647,008 bp provides a resource for the identification of crude oil-degrading mechanisms in strain MWB30.

Draft Genome Sequence of Sphingopyxis sp. Strain MWB1, a Crude-Oil-Degrading Marine Bacterium.

Sphingopyxis sp. strain MWB1, which is capable of degrading crude oil, diesel, and kerosene, was isolated from crude oil-contaminated seashore in Tae-an, South Korea. Here, we report the draft genome sequence of this strain, which comprises 3,118,428 bp with a G+C content of 62.85 mol%.

Cyanobacterial phytochrome Cph2 is a negative regulator in phototaxis toward UV-A.

We investigated the wavelength dependence and photon-fluence rate response relationship for phototaxis of wild-type and a cyanobacterial phytochrome 2 (cph2) mutant in cyanobacterium Synechocystis sp. PCC 6803. Compared to wild-type, the cph2 mutant exhibited maximal activity for positive phototaxis at the near-UV spectral range. Two cysteine to serine substitutions in two chromophore-binding domains showed a similar cph2 mutant phenotype under UV-A. Epistasis of a pixJ mutation over a cph2 mutation implied that pixJ gene acts downstream of the cph2 gene with respect to UV-A-induced positive phototaxis. Therefore, we suggest that Cph2 is essential for the inhibition of positive phototaxis toward UV-A.