Project description:Methanogens inhabit euxinic (sulfide-rich) or ferruginous (iron-rich) environments that promote the precipitation of transition metals as metal sulfides, such as pyrite, reducing metal or sulfur availability. Such environments have been common throughout Earth’s history raising the question as to how anaerobes obtain(ed) these elements for the synthesis of enzyme cofactors. Here, we show a methanogen can synthesize molybdenum nitrogenase metallocofactors from pyrite as the source of iron and sulfur, enabling nitrogen fixation. Pyrite-grown, nitrogen-fixing cells grow faster and require 25-fold less molybdenum than cells grown under euxinic conditions. Growth yields are 3 to 8 times higher in cultures grown under ferruginous relative to euxinic conditions. Physiological, transcriptomic, and geochemical data indicate these observations are due to sulfide-promoted metal limitation, in particular molybdenum. These findings suggest that molybdenum nitrogenase may have originated in a ferruginous environment that titrated sulfide to form pyrite, facilitating the availability of sufficient iron, sulfur, and molybdenum for cofactor biosynthesis.

2023-05-01 | GSE216895 | GEO

Transcriptome comparison of wild type Azoarcus sp. strain BH72 grown under nitrogen fixation (experiment) with cells grown with combined nitrogen (ammonia) as nitrogen source

Project description:Model endophyte Azoarcus sp. BH72 is known to contribute fixed nitrogen to its host Kallar grass by nitrogen fixation and also expresses nitrogenase genes endophytically in rice seedlings in gnotobiotic culture. Availability of fixed nitrogen is one of the important signals regulating the transcription of nitrogenase genes and hence nitrogen fixing activity. Therefore, we analysed global transcription in response to differences in the nitrogen source. Transcription profiles of cells grown microaerobically (0.6% oxygen) on minimal medium with nitrogen (N2-fixing) versus ammonium (combined nitrogen) were compared using a genome-wide microarray approach and differences in the gene expression profile were monitored.

2013-08-01 | GSE49394 | GEO

Methanobacterium thermautotrophicus temperature-stress LC-MSMS

Project description:Methanothermobacter thermautotrophicus is a model thermophilic hydrogenotrophic methanogen. The life and survival of M. thermautotrophicus is highly influenced by the availability of nutrients and temperature. To learn about adaptation mechanisms evolved by the archaea to cope with drastic temperature shifts, the responses of model M. thermautotrophicus ΔH to temperature were investigated using a quantitative proteomics approach with iTRAQ-LC-MS/MS.

2018-10-02 | PXD006685 | Pride

Transcriptome comparison of the wild type strain Azoarcus sp. BH72 with that of nifLA knockout strain under nitrogen fixing condition

Project description:Azoarcus sp. BH72 is known to express nitrogenase genes endophytically in rice seedlings in gnotobiotic culture. Availability of fixed nitrogen is one of the important signals regulating the transcription of nitrogenase genes and hence nitrogen fixing activity. NifA is the essential transcription activator of nif genes. RNA isolated from the nifA knockout mutant of strain BH72 was compared with the transcriptome of wild type under nitrogen fixing condition using a global genome wide microarray approach and the differences in the gene expression profile were monitered.

2013-08-15 | GSE49912 | GEO

Sinorhizobium meliloti 1021

Project description:Nitrogen-fixing bacterium

| PRJNA19 | ENA

Gloeothece citriformis PCC 7424

Project description:Nitrogen-fixing cyanobacterium

| PRJNA20479 | ENA