Ontology highlight
ABSTRACT:
PROVIDER: PRJNA560450 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR9985080_1.fastq.gz | Fastqsanger.gz | |||
| SRR9985080_2.fastq.gz | Fastqsanger.gz | |||
| SRR9985090_1.fastq.gz | Fastqsanger.gz | |||
| SRR9985090_2.fastq.gz | Fastqsanger.gz | |||
| SRR9985100_1.fastq.gz | Fastqsanger.gz |
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Project description:Pelagic aggregates function as hotspots for microbial activity and biological carbon pumps for exporting OM fixed by photoautotrophs to sediments in lakes and oceans. In iron-rich (ferruginous) lakes, photoferrotrophic or chemolithoautotrophic bacteria appear to contribute to CO2 fixation by oxidizing reduced iron which leads to the formation of iron-rich pelagic aggregates called iron-snow. In acidic lakes, iron snow is colonized mainly by acidophilic iron-cycling microbes that can trigger interspecies aggregation mechanisms. However, the significance of iron oxidizers in carbon fixation, their general role in iron snow functioning, and the flow of carbon within iron snow is still unclear. Here, we combined a two-year metatranscriptome analysis with a 13CO2 metabolic labeling approach to determine general metabolic activities. Protein-based stable isotope probing (protein-SIP) was used to trace the 13CO2 incorporation in iron snow microcosms over time under both oxic and anoxic conditions. Analysis of our mRNA-derived metatranscriptome data identified four key players (Leptospirillum, Ferrovum, Acidithrix, Acidiphilium) with relative abundances (59.6%-85.7%) in iron snow encoding a variety of ecologically relevant pathways, including carbon fixation, polysaccharide biosynthesis, and flagellar-based motility. We did not detect transcriptional activity for carbon fixation from archaea or eukaryotes. The largest numbers of expressed genes (3008, 2991, 2936) matched to the genomes of our previously obtained iron snow isolates (Acidithrix sp. C25, Acidiphilium sp. C61, Acidocella sp. C78) separately. 13CO2 incorporation studies identified Leptospirillum and Ferrovum, as the main active chemolithoautotrophs under oxic conditions, and Ferrovum was the main active organism under anoxic conditions as well. Small amounts of labeled 13C (Relative isotope abundance: 1.0%-5.3%) were found in the heterotrophic Acidiphilium and Acidocella. Overall, our data show that iron oxidizers play an important role in the formation of iron minerals and CO2 fixation, but the majority of fixed C apparently did not reach other iron snow microbes. This finding suggests that most of the fixed C will be directly exported to the sediment without feeding heterotrophs in the water column in acidic ferruginous lakes.
2022-02-17 | PXD025534 | Pride
Project description:Coastal Antarctic marine ecosystems play an important role in carbon cycling due to their highly productive seasonal phytoplankton blooms. Southern Ocean microbes are primarily limited by light and iron (Fe) and can be co-limited by cobalamin (vitamin B12 ). Micronutrient limitation is a key driver of ecosystem dynamics and influences the composition of blooms, which are often dominated by either diatoms or the haptophyte Phaeocystis antarctica, each with varied impacts on carbon cycling. However, the vitamin requirements and ecophysiology of the keystone species P. antarctica remains poorly characterized. Using cultures, physiological analysis, and comparative ’omics we examined the response of P. antarctica to a matrix of Fe-B12 conditions. We show that P. antarctica is not auxotrophic for B12 , as previously suggested, and report new mechanistic insights of its B12 response in cultures of predominantly solitary and colonial cells. Proteomics coupled with proteogenomics detected a B12 -independent methionine synthase fusion protein (MetE-fusion) that is expressed under vitamin limitation and is interreplaced with the B12 -dependent isoform (MetH) in replete conditions. Database searches returned homologs of the MetE-fusion protein in multiple Phaeocystis species and in a wide range of marine microbes, including other photosynthetic eukaryotes with polymorphic life cycles and also bacterioplankton. Furthermore, MetE-fusion homologs were found to be expressed in metaproteomic and metatranscriptomic field samples in polar and more geographically widespread regions. As climate change impacts micronutrient availability in the coastal Southern Ocean, our finding that P. antarctica has a flexible B12 metabolism has implications for its relative fitness compared to B12 -auxotrophic diatoms.
2023-02-27 | PXD031524 | Pride
Project description:Haloalkaliphilic microorganisms are double extremophiles functioning optimally at high salinity and pH. Their typical habitats are soda lakes, representing geologically ancient ecosystems which are still widespread on Earth and supposedly harbor relict microbial communities. We compared metabolic features and their genomic determinants in two strains of a single natronophilic species Dethiobacter alkaliphilus, the only cultured representative of “Dethiobacteria” class within Bacillota phylum. The strains of D. alkaliphilus were previously isolated from geographically remote Mongolian and Kenyan soda lakes. The type strain AHT1T was described as a facultatively chemolithoautotrophic sulfidogen reducing or disproportionating sulfur or thiosulfate, while strain Z-1002 was isolated as a chemolithoautotrophic iron reducer. Here, we uncovered iron reducing ability of strain AHT1T, as well as the capability of strain Z-1002 for thiosulfate reduction and anaerobic Fe(II) oxidation. Key catabolic processes sustaining the growth of both strains appeared to fit the geochemical settings of two contrasting natural alkaline environments, sulfur-enriched soda lakes and iron-enriched serpentinites. This assumption was supported by meta-analysis of publicly available Dethiobacterial metagenomes, as well as by the enrichment of a novel phylotype from a deep subsurface non-serpentinizing slightly alkaline water after its amendment with an Fe(III) mineral. Genome analysis of D. alkaliphilus strains revealed that the most probable determinants of iron and sulfur redox transformations in the organism are multiheme c-type cytochromes. Their phylogeny reconstruction showed that sulfur and thiosulfate respiration is most probably provided by evolutionary early forms of unconventional octaheme tetrathionate and sulfite reductases sharing a root with structurally similar group of OmhA/OcwA Fe(III)-reductases. Large sets of other multihemes are likely to provide Fe(III) reduction in both strains. Also, several different, yet phylogenetically related, determinants of anaerobic Fe(II) oxidation were identified in Z-1002 genome, and the oxidation process was further experimentally proven. Considering these results and phylogenetic relatedness of D. alkaliphilus’s sulfur reductases with Fe(III) reducing cytochromes, but not with archetypal bacterial sulfur/thiosulfate reductases, we suggest that sustaining high variation of multiheme cytochromes is an effective adaptive strategy to occupy geochemically contrasting alkaline anaerobic environments. We further propose that sulfur-enriched soda lakes are secondary habitats for D. alkaliphilus comparing to Fe-rich serpentinites, and discuss the evolutionary traits which might occur in prokaryotes on a crucial junction of the biosphere’s history, when intensification of the sulfur cycle outweighed the global significance of the iron cycle.
2023-10-24 | PXD040929 | Pride
Project description:Anthropogenic nitrogen (N) deposition may affect soil organic carbon (SOC) decomposition, thus affecting the global terrestrial carbon (C) cycle. However, it remains unclear how the level of N deposition affects SOC decomposition by regulating microbial community composition and function, especially C-cycling functional genes structure. We investigated the effects of short-term N addition on soil microbial C-cycling functional gene composition, SOC-degrading enzyme activities, and CO2 emission in a 5-year field experiment established in an artificial Pinus tabulaeformis forest on the Loess Plateau, China.
2022-03-01 | GSE147041 | GEO
Project description:This study used an emerging analytical technology (cDNA microarrays) to assess the potential effects of PFC exposure on largemouth bass in TCMA lakes. Microarrays simultaneously measure the expression of thousands of genes in various tissues from organisms exposed to different environmental conditions. From this large data set, biomarkers (i.e., genes that are expressed in response to an exposure to known stressors) and bioindicators (e.g., suites of genes that correspond to changes in organism health) can be simultaneously measured to clarify the relationship between contaminant exposure and organism health. Based on current scientific literature, we hypothesized that gene expression patterns would be altered in fish exposed to PFCs (as compared with fish from reference lakes), and that the magnitude of these changes would correspond to the concentrations of PFCs present throughout TCMA lakes. Patterns of gene expression in largemouth bass observed across the TCMA lakes corresponded closely with PFC concentration. Concentrations of PFCs in largemouth bass varied significantly across the sampled lakes, where the lowest concentrations were found in Steiger and Upper Prior Lakes and the highest concentrations were found in Calhoun and Twin Lakes. Patterns of gene expression were most different (relative to controls) in fish with the highest PFC tissue concentrations, where fish from Twin and Calhoun Lakes were observed to have between 5437 and 5936 differentially expressed genes in liver and gonad tissues. Although gene expression patterns demonstrated a high degree of correlation with PFC concentrations, microarray data also suggest there are likely additional factors influencing gene expression patterns in largemouth bass in TCMA lakes.
2014-07-31 | GSE57684 | GEO