Project description:The objective of this study was to assess whether Methylocystis sp. strain SC2, as a representative for Methylocystis spp., can utilize hydrogen to optimize the biomass yield by mixed utilization of CH4 and H2, rather than CH4 as the sole source of energy. Thus, we aimed to show that, in the presence of H2, CH4 will primarily be used for synthesis of cell carbon and increased biomass/protein yield. In particular, we intended to explore those CH4/O2 ratios, which maximize the effect of hydrogen addition on the biomass yield and proteome reconstruction of strain SC2. To achieve our goals, we combined hydrogen-based growth experiments with our recently optimized proteomics workflow.
Project description:Methanotrophs, which help regulate atmospheric levels of methane, are active in diverse natural and man-made environments. This range of habitats and the feast-famine cycles seen by many environmental methanotrophs suggest that methanotrophs dynamically mediate rates of methane oxidation. Global methane budgets require ways to account for this variability in time and space. Functional gene biomarker transcripts are increasingly being studied to inform the dynamics of diverse biogeochemical cycles. Previously, per-cell transcript levels of the methane oxidation biomarker, pmoA, were found to vary quantitatively with respect to methane oxidation rates in model aerobic methanotroph, Methylosinus trichosporium OB3b. In the present study, these trends were explored for two additional aerobic methanotroph pure cultures, Methylocystis parvus OBBP and Methylomicrobium album BG8. At steady-state conditions, per cell pmoA mRNA transcript levels strongly correlated with per cell methane oxidation across the three methanotrophs across many orders of magnitude of activity (R2 = 0.91). Additionally, genome-wide expression data (RNA-seq) were used to explore transcriptomic responses of steady state M. album BG8 cultures to short-term CH4 and O2 limitation. These limitations induced regulation of genes involved in central carbon metabolism (including carbon storage), cell motility, and stress response.
Project description:Previous studies have shown that methane (CH4) has promoting roles in the adventitious root (AR) and lateral root formation in plants. However, whether CH4 could trigger the bulblet formation in scale cutting of Lilium davidii var. unicolor has not been elucidated. To gain insight into the effect of CH4 on the bulblet formation, different concentrations (1%, 10%,50% and 100%) of methane-rich water (MRW) and distilled water were applied to treat the scale cuttings of Lilium. We observed that treatment with 100% MRW obviously induced the bulblet formation in scale cuttings. To explore the mechanism of CH4-induced the bulblet formation, the transcriptome of scales was analyzed. A total of 2078 differentially expressed genes (DEGs) were identified. The DEGs were classified into different metabolism pathways, especially phenylpropanoid biosynthesis, starch and sucrose metabolism and plant signal transduction. Of these, approximately 38 candidate DEGs involved in the plant signal transduction were further studied. In addition, the expression of AP2-ERF/ERF, WRKY, GRAS, ARF and NAC transcription factors were changed by MRW treatment, suggesting their potential involvement in bulblet formation. As for hormones, exogenous IAA, GA and ABA could indue the bulblet formation. Additional experiments suggested that MRW could increase the endogenous IAA, GA, and JA levels, but decrease the levels of ABA during bulblet formation, which showed that higher IAA, GA, JA levels and lower ABA content might facilitate bulblet formation. In addition, the levels of endogenous hormone were consistent with the expression level of genes involved in phytohormone signal transduction. Overall, this study has revealed that CH4 might improve the bulblet formation of cutting scales in Lilium by regulating the expression of genes related to phytohormone signal transduction and transcription factors, as well as by changing the endogenous hormone levels.
Project description:Sorbose resistant Candida albicans mutant strain [Sor125(55)] derived from parental strain [3153A] has characteristic Ch5 monosomy plus Ch4/7b trisomy. ChIP-chip data showed marked elevation of H4 histone acetylation on monosomic Ch5 in Sor125(55) mutant compared with parental strain (3153A). There was no remarkable diffrence in H4 acetylation level on other chromosomes between those strains and no difference in H3 acetylation on all chromosomes.
Project description:Investigation of the cellular adjustments required for life on air by M. gorgona MG08, M. rosea SV97, and M. palsarum NE2 by comparing the proteomes of the three strains when exposed to air (~1.9 p.p.m.v. CH4) and when exposed to high CH4 concentrations (~1000 p.p.m.v. CH4) in air
Project description:A 45-kDa membrane polypeptide that is associated with activity of the particulate methane monooxygenase (pMMO) has been purified from three methanotrophic bacteria, and the N-terminal amino acid sequence was found to be identical in 17 of 20 positions for all three polypeptides and identical in 14 of 20 positions for the N terminus of AmoB, the 43-kDa subunit of ammonia monooxygenase. DNA from a variety of methanotrophs was screened with two probes, an oligonucleotide designed from the N-terminal sequence of the 45-kDa polypeptide from Methylococcus capsulatus Bath and an internal fragment of amoA, which encodes the 27-kDa subunit of ammonia monooxygenase. In most cases, two hybridizing fragments were identified with each probe. Three overlapping DNA fragments containing one of the copies of the gene encoding the 45-kDa pMMO polypeptide (pmoB) were cloned from Methylococcus capsulatus Bath. A 2.1-kb region was sequenced and found to contain both pmoB and a second gene, pmoA. The predicted amino acid sequences of these genes revealed high identity with those of the gene products of amoB and amoA, respectively. Further hybridization experiments with DNA from Methylococcus capsulatus Bath and Methylobacter albus BG8 confirmed the presence of two copies of pmoB in both strains. These results suggest that the 45- and 27-kDa pMMO-associated polypeptides of methanotrophs are subunits of the pMMO and are present in duplicate gene copies in methanotrophs.