Dataset Information

Subgroup level differences of physiological activities in marine Lokiarchaeota.

ABSTRACT: Asgard is a recently discovered archaeal superphylum, closely linked to the emergence of eukaryotes. Among Asgard archaea, Lokiarchaeota are abundant in marine sediments, but their in situ activities are largely unknown except for Candidatus 'Prometheoarchaeum syntrophicum'. Here, we tracked the activity of Lokiarchaeota in incubations with Helgoland mud area sediments (North Sea) by stable isotope probing (SIP) with organic polymers, ¹³C-labelled inorganic carbon, fermentation intermediates and proteins. Within the active archaea, we detected members of the Lokiarchaeota class Loki-3, which appeared to mixotrophically participate in the degradation of lignin and humic acids while assimilating CO₂, or heterotrophically used lactate. In contrast, members of the Lokiarchaeota class Loki-2 utilized protein and inorganic carbon, and degraded bacterial biomass formed in incubations. Metagenomic analysis revealed pathways for lactate degradation, and involvement in aromatic compound degradation in Loki-3, while the less globally distributed Loki-2 instead rely on protein degradation. We conclude that Lokiarchaeotal subgroups vary in their metabolic capabilities despite overlaps in their genomic equipment, and suggest that these subgroups occupy different ecologic niches in marine sediments.

SUBMITTER: Yin X

PROVIDER: S-EPMC8027215 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature

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Subgroup level differences of physiological activities in marine Lokiarchaeota.

Yin Xiuran X Cai Mingwei M Liu Yang Y Zhou Guowei G Richter-Heitmann Tim T Aromokeye David A DA Kulkarni Ajinkya C AC Nimzyk Rolf R Cullhed Henrik H Zhou Zhichao Z Pan Jie J Yang Yuchun Y Gu Ji-Dong JD Elvert Marcus M Li Meng M Friedrich Michael W MW

The ISME journal 20201104 3

Asgard is a recently discovered archaeal superphylum, closely linked to the emergence of eukaryotes. Among Asgard archaea, Lokiarchaeota are abundant in marine sediments, but their in situ activities are largely unknown except for Candidatus 'Prometheoarchaeum syntrophicum'. Here, we tracked the activity of Lokiarchaeota in incubations with Helgoland mud area sediments (North Sea) by stable isotope probing (SIP) with organic polymers, <sup>13</sup>C-labelled inorganic carbon, fermentation interm ...[more]

PMID: 33149207

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Project description:BackgroundThe distribution of prey in the ocean is spatially and temporally patchy. How predators respond to this prey patchiness may have consequences on their foraging success, and thus physical condition. The recent ability to record fine-scale movements of marine animals combined with novel home-range analyses that incorporate the dimension of time should permit a better understanding of how individuals utilise different regions of space and the consequences on their foraging success.MethodsOver a six-year study, we used T-LoCoH (Time-Local Convex Hull) home-range software to model archival GPS (Global Positioning System) data from 81 grey seals to investigate the fine-scale spatio-temporal use of space and the distribution of apparent foraging effort. Regions of home-ranges were classified according to the frequency of return visits (site fidelity) and duration of visits (intensity of use). Generalized linear mixed -effects models were used to test hypotheses on seasonal changes in foraging distribution and behaviour and the role of space-use and state on determining foraging success.ResultsMale grey seals had larger home-ranges and core areas than females, and both sexes showed a contraction in home-range and core area in fall leading up to the breeding season compared with summer. Heavier individuals had smaller core areas than lighter ones, suggesting access to higher quality habitat might be limited to those individuals with greater foraging experience and competitive ability. The size of the home-range or core area was not an important predictor of the rate of mass gain. A fine-scale spatio-temporal analysis of habitat use within the home-range provided evidence of intra-annual site fidelity at presumed foraging locations, suggesting predictably in prey distribution. Neither sex nor season were useful predictors for classifying behaviour. Rather, individual identity explained much of the variation in fine-scale behaviour.ConclusionsUnderstanding how upper-trophic level marine predators use space provides opportunities to explore the consequences of variation in foraging tactics and their success on fitness. Having knowledge of the drivers that shape this intraspecific variation can contribute toward predicting how these predators may respond to both natural and man-made environmental forcing.

Project description:Trichodesmium is a globally distributed cyanobacterium whose nitrogen-fixing capability fuels primary production in warm oligotrophic oceans. Like many photoautotrophs, Trichodesmium serves as a host to various other microorganisms, yet little is known about how this associated community modulates fluxes of environmentally relevant chemical species into and out of the supraorganismal structure. Here, we utilized metatranscriptomics to examine gene expression activities of microbial communities associated with Trichodesmium erythraeum (strain IMS101) using laboratory-maintained enrichment cultures that have previously been shown to harbor microbial communities similar to those of natural populations. In enrichments maintained under two distinct CO2 concentrations for ∼8 years, the community transcriptional profiles were found to be specific to the treatment, demonstrating a restructuring of overall gene expression had occurred. Some of this restructuring involved significant increases in community respiration-related transcripts under elevated CO2, potentially facilitating the corresponding measured increases in host nitrogen fixation rates. Particularly of note, in both treatments, community transcripts involved in the reduction of nitrate, nitrite, and nitrous oxide were detected, suggesting the associated organisms may play a role in colony-level nitrogen cycling. Lastly, a taxon-specific analysis revealed distinct ecological niches of consistently cooccurring major taxa that may enable, or even encourage, the stable cohabitation of a diverse community within Trichodesmium consortia.IMPORTANCETrichodesmium is a genus of globally distributed, nitrogen-fixing marine cyanobacteria. As a source of new nitrogen in otherwise nitrogen-deficient systems, these organisms help fuel carbon fixation carried out by other more abundant photoautotrophs and thereby have significant roles in global nitrogen and carbon cycling. Members of the Trichodesmium genus tend to form large macroscopic colonies that appear to perpetually host an association of diverse interacting microbes distinct from the surrounding seawater, potentially making the entire assemblage a unique miniature ecosystem. Since its first successful cultivation in the early 1990s, there have been questions about the potential interdependencies between Trichodesmium and its associated microbial community and whether the host's seemingly enigmatic nitrogen fixation schema somehow involved or benefited from its epibionts. Here, we revisit these old questions with new technology and investigate gene expression activities of microbial communities living in association with Trichodesmium.

Dataset Information

Subgroup level differences of physiological activities in marine Lokiarchaeota.

Publications

Subgroup level differences of physiological activities in marine Lokiarchaeota.

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