Nitrate respiration in chemoautotrophic symbionts of the bivalve Lucinoma aequizonata

Hentschel, Ute; Cary, S. Craig; Felbeck, Horst

doi:10.3354/meps094035

Cited by 45 publications

(36 citation statements)

References 24 publications

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“…Because very high concentrations of ammonia (980 pm01 g-' dry wt) had been measured previously in the tissues of Inanidrilus leukodermatus (Giere et al 1991), ammonia could possibly be the end product of respiratory nitrate reduction in I. leukodermatus symbionts. Nitrate respiration/denitrification has also been demonstrated in chemoautotrophic symbionts of the bivalves Lucinoma aequizonata , Hentschel & Felbeck 1995, Solemya reidi (Wilmot & Vetter 1992, Hentschel unpubl. res.…”

Section: Discussionmentioning

confidence: 99%

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Metabolism of nitrogen and sulfur in ectosymbiotic bacteria of marine nematodes (Nematoda, Stilbonematinae)

Hentschel¹,

Berger²,

Bright³

et al. 1999

Mar. Ecol. Prog. Ser.

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Nematodes of the family Stilbonematinae are known for their hlghly specific association with ectosymbiotic bacteria. These worms are members of the meiofauna in marine, sulfide-rich sediments, where they migrate around the redox boundary layer. In this study, bacterial ectosymbionts of 2 species of marine nematodes, Stilbonema sp. and Laxus oneistus, were shown to be capable of the respiratory reduction of nitrate and nitrite (denitrification). The use of these alternative electron acceptors to oxygen by the bacteria allows the anlmals to migrate into the deeper, anoxic sedirnents, where they can exploit the sulfide-rich patches of the deeper sediment layers. The accumulation of thiols (sulfide, thiosulfate, sulfate and glutathione) in body tissues of the worms was determined following incubation in the presence of various electron donors (sulfide, thiosulfate) and acceptors (nitrate). In their chemoautotrophic metabolic potential, the ectosymbionts of the 2 nematode species were found to resemble the phylogenetically related, intracellular symbionts of macrofaunal hosts of deep-sea hydrothermal vents and other sulfide-rich habitats.

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Section: Discussionmentioning

confidence: 99%

“…It allows the bacteria to utilize the respiratory chain even under anaerobic conditions. Because nitrate is used as an alternative to oxygen, nitrate respiration is, with a few notable exceptions (Hentschel & Felbeck 1995), an anaerobic process.…”

Section: Worm Recolonisationmentioning

confidence: 99%

Metabolism of nitrogen and sulfur in ectosymbiotic bacteria of marine nematodes (Nematoda, Stilbonematinae)

Hentschel¹,

Berger²,

Bright³

et al. 1999

Mar. Ecol. Prog. Ser.

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“…This activity was assayed using a protocol similar to that of Orengo and Kobayashi (30) and Ives et al (31). A 50-l sample of extract (0.5-1.5 mg of protein) was incubated for 1 h at 37°C in the presence of 50 mM Tris-HCl, pH 8, 5 mM ATP, 5 mM GTP, 5 mM MgCl 2 , and 1 mM [2- Nitrate Reductase Assay-The NRase activity was assayed using a protocol similar to that of Hentschel et al (33).…”

Section: Methodsmentioning

confidence: 99%

Contribution of the Bacterial Endosymbiont to the Biosynthesis of Pyrimidine Nucleotides in the Deep-sea Tube Worm Riftia pachyptila

Minić

Simon

Penverne

et al. 2001

Journal of Biological Chemistry

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The deep-sea tube worm Riftia pachyptila (Vestimentifera) from hydrothermal vents lives in an intimate symbiosis with a sulfur-oxidizing bacterium. That involves specific interactions and obligatory metabolic exchanges between the two organisms. In this work, we analyzed the contribution of the two partners to the biosynthesis of pyrimidine nucleotides through both the "de novo" and "salvage" pathways. The first three enzymes of the de novo pathway, carbamyl-phosphate synthetase, aspartate transcarbamylase, and dihydroorotase, were present only in the trophosome, the symbiont-containing tissue. The study of these enzymes in terms of their catalytic and regulatory properties in both the trophosome and the isolated symbiotic bacteria provided a clear indication of the microbial origin of these enzymes. In contrast, the succeeding enzymes of this de novo pathway, dihydroorotate dehydrogenase and orotate phosphoribosyltransferase, were present in all body parts of the worm. This finding indicates that the animal is fully dependent on the symbiont for the de novo biosynthesis of pyrimidines. In addition, it suggests that the synthesis of pyrimidines in other tissues is possible from the intermediary metabolites provided by the trophosomal tissue and from nucleic acid degradation products since the enzymes of the salvage pathway appear to be present in all tissues of the worm. Analysis of these salvage pathway enzymes in the trophosome strongly suggested that these enzymes belong to the worm. In accordance with this conclusion, none of these enzyme activities was found in the isolated bacteria. The enzymes involved in the production of the precursors of carbamyl phosphate and nitrogen assimilation, glutamine synthetase and nitrate reductase, were also investigated, and it appears that these two enzymes are present in the bacteria.

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“…These forms are metazoan extremophiles and are characteristic of the most sulfiderich, methane-rich, and oxygen-poor environments of modern continental margins (35)(36)(37). Many of these extremophiles are opportunistic, weedy species and appear in high-density (∼900 individuals/m 2 ) zonations on modern continental margins (22,(38)(39)(40). Deposit feeding, suspension feeding, and detritivorous and carnivorous trophic guilds are also present within the molluscan assemblage.…”

Section: Mv0811-15jc Biotic Recordmentioning

confidence: 99%

Response of seafloor ecosystems to abrupt global climate change

Moffitt

Hill

Roopnarine

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Anthropogenic climate change is predicted to decrease oceanic oxygen (O 2 ) concentrations, with potentially significant effects on marine ecosystems. Geologically recent episodes of abrupt climatic warming provide opportunities to assess the effects of changing oxygenation on marine communities. Thus far, this knowledge has been largely restricted to investigations using Foraminifera, with little being known about ecosystem-scale responses to abrupt, climate-forced deoxygenation. We here present high-resolution records based on the first comprehensive quantitative analysis, to our knowledge, of changes in marine metazoans (Mollusca, Echinodermata, Arthropoda, and Annelida; >5,400 fossils and trace fossils) in response to the global warming associated with the last glacial to interglacial episode. The molluscan archive is dominated by extremophile taxa, including those containing endosymbiotic sulfur-oxidizing bacteria (Lucinoma aequizonatum) and those that graze on filamentous sulfur-oxidizing benthic bacterial mats (Alia permodesta). This record, from 16,100 to 3,400 y ago, demonstrates that seafloor invertebrate communities are subject to major turnover in response to relatively minor inferred changes in oxygenation (>1.5 to <0.5 mL·L −1 [O 2 ]) associated with abrupt (<100 y) warming of the eastern Pacific. The biotic turnover and recovery events within the record expand known rates of marine biological recovery by an order of magnitude, from <100 to >1,000 y, and illustrate the crucial role of climate and oceanographic change in driving long-term successional changes in ocean ecosystems.seafloor ecosystems | abrupt climate change | deglaciation | oxygen minimum zone | metazoans O ceanic deoxygenation is a predictable, fundamental, and long-lasting property of anthropogenic climate change (1). The global ocean inventory of oxygen is predicted to decline between 1% and 7% by the year 2100, and modeling predictions reveal extensive oceanic deoxygenation, on thousand-year timescales, under "business-as-usual" carbon emission scenarios (2). Modern oceanographic time series already document rapid loss of [O 2 ] in interior ocean waters over the last 4 decades (3, 4), although this trend is complicated in regions where [O 2 ] demand is decreased through the slackening of trade winds (5). As oxygen levels in the ocean decrease and the already extensive oxygen minimum zones (OMZs) expand, the volumetric habitat for aerobic respiration is reduced, presumably resulting in a fundamental reorganization of marine communities. Past events of climate warming and OMZ expansion, including the recent deglaciation from 18 to 11 ka, provide a case study for understanding the effects on marine ecosystems of abrupt temperature and oxygenation changes.Paleoceanographic records clearly demonstrate that OMZ strength changed in response to

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Nitrate respiration in chemoautotrophic symbionts of the bivalve Lucinoma aequizonata

Cited by 45 publications

References 24 publications

Metabolism of nitrogen and sulfur in ectosymbiotic bacteria of marine nematodes (Nematoda, Stilbonematinae)

Metabolism of nitrogen and sulfur in ectosymbiotic bacteria of marine nematodes (Nematoda, Stilbonematinae)

Contribution of the Bacterial Endosymbiont to the Biosynthesis of Pyrimidine Nucleotides in the Deep-sea Tube Worm Riftia pachyptila

Response of seafloor ecosystems to abrupt global climate change

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