نتایج جستجو برای: archaea
تعداد نتایج: 7833 فیلتر نتایج به سال:
There’s an old joke that circulates in newsrooms. A reporter rushes up to City Desk and breathlessly tells his editor that he has confirmed the Second Coming of Christ. The editor doesn’t want the story. “We had that one already — 2 000 years ago.” If it’s news, it has to be the first, the biggest, the oldest or the most, especially in science news. So, how do you make the papers if you’ve comp...
During the last few years, the analysis of microbial diversity in various habitats greatly increased our knowledge on the kingdom Archaea. At the same time, we became aware of the multiple ways in which Archaea may interact with each other and with organisms of other kingdoms. The large group of euryarchaeal methanogens and their methane oxidizing relatives, in particular, take part in essentia...
The gene-dense chromosomes of archaea and bacteria were long thought to be devoid of pseudogenes, but with the massive increase in available genome sequences, whole genome comparisons between closely related species have identified mutations that have rendered numerous genes inactive. Comparative analyses of sequenced archaeal genomes revealed numerous pseudogenes, which can constitute up to 8....
The anaerobic oxidation of methane (AOM) is one of the major sinks of this substantial greenhouse gas in marine environments. Recent investigations have shown that diverse communities of anaerobic archaea and sulfate-reducing bacteria are involved in AOM. Most of the relevant archaea are assigned to two distinct phylogenetic clusters, ANME-1 and ANME-2. A suite of specific (13)C-depleted lipids...
ANaerobic MEthanotrophic (ANME) archaea remove the greenhouse gas methane from anoxic environments and diminish its flux to the atmosphere. High methane removal efficiencies are well documented in marine environments, whereas anaerobic oxidation of methane (AOM) was only recently indicated as an important methane sink in freshwater systems. Freshwater AOM-mediating microorganisms lack taxonomic...
One potential approach for characterizing uncultivated prokaryotes from natural assemblages involves genomic analysis of DNA fragments retrieved directly from naturally occurring microbial biomass. In this study, we sought to isolate large genomic fragments from a widely distributed and relatively abundant but as yet uncultivated group of prokaryotes, the planktonic marine Archaea. A fosmid DNA...
Anaerobic methanotrophic archaea have recently been identified in anoxic marine sediments, but have not yet been recovered in pure culture. Physiological studies on freshly collected samples containing archaea and their sulfate-reducing syntrophic partners have been conducted, but sample availability and viability can limit the scope of these experiments. To better study microbial anaerobic met...
Genomics studies are helping to reveal how bacteria and archaea influence one of Earth’s largest carbon stores as it begins thaw.
Metagenomics has provided access to genomes of as yet uncultivated microorganisms in natural environments, yet there are gaps in our knowledge-particularly for Archaea-that occur at relatively low abundance and in extreme environments. Ultrasmall cells (<500 nm in diameter) from lineages without cultivated representatives that branch near the crenarchaeal/euryarchaeal divide have been detected ...
Studying the microbial diversity of a unique biome such as the McMurdo Dry Valleys, Antarctica, is important to understand the sustainability of life under cold-arid conditions where other forms of life (i.e., plants and animals) do not exist. Pointing et al. (1) examined multidomain microbial diversity in the McKelvey valley using culture-independent molecular approaches and interestingly foun...
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