Chemoautotrophic function of bacterial symbionts in small Pogonophora

Author(s):  
A. J. Southward ◽  
Eve C. Southward ◽  
P. R. Dando ◽  
R. L. Barrett ◽  
R. Ling

INTRODUCTIONThe small species of Pogonophora that are widely distributed in sediments along the Continental Slope and in the Norwegian fjords (Webb, 1965; Southward & Southward, 1967; Southward, 1971,1979) carry Gram-negative bacteria in the posterior part of the body (Southward, 1982). In this they resemble the giant pogonophores (Vestimentifera) that live around hydrothermal vents in the Pacific ocean floor (Cavanaugh et al. 1981; Cavanaugh, 1983). The bacteria in both groups are autotrophic (Felbeck, 1981; Southward et al. 1981), capable of synthesizing organic matter from carbon dioxide. The bacteria in Riftia and other vent pogonophores appear to obtain energy by oxidation of reduced sulphur compounds (Felbeck, 1981; Felbeck, Childress & Somero, 1981). Hydrothermal vent waters may contain as much as 6 nut dissolved sulphide (Edmond et al. 1982; Edmond & Von Damm, 1983), which is diluted to about 200-300 μM near the giant pogonophores, whose blood can transport sulphide without affecting the affinity of its haemoglobin for oxygen (Arp & Childress, 1983; Powell & Somero, 1983; Childress, Arp & Fisher, 1984).

ZooKeys ◽  
2018 ◽  
Vol 779 ◽  
pp. 89-107
Author(s):  
Marina F. McCowin ◽  
Greg W. Rouse

The scale-worm family Iphionidae consists of four genera. Of these, Thermiphione has two accepted species, both native to hydrothermal vents in the Pacific Ocean; T.fijiensis Miura, 1994 (West Pacific) and T.tufari Hartmann-Schröder, 1992 (East Pacific Rise). Iphionella is also known from the Pacific, and has two recognized species; Iphionellarisensis Pettibone, 1986 (East Pacific Rise, hydrothermal vents) and I.philippinensis Pettibone, 1986 (West Pacific, deep sea). In this study, phylogenetic analyses of Iphionidae from various hydrothermal vent systems of the Pacific Ocean were conducted utilizing morphology and mitochondrial (COI and 16S rRNA) and nuclear (18S and 28S rRNA) genes. The results revealed a new iphionid species, described here as Thermiphionerapanuisp. n. The analyses also demonstrated the paraphyly of Thermiphione, requiring Iphionellarisensis to be referred to the genus, as Thermiphionerisensis (Pettibone, 1986).


2020 ◽  
Author(s):  
Yi Lan ◽  
Jin Sun ◽  
Chong Chen ◽  
Yanan Sun ◽  
Yadong Zhou ◽  
...  

AbstractAnimals endemic to deep-sea hydrothermal vents often form obligatory relationships with bacterial symbionts, maintained by intricate host-symbiont interactions. Endosymbiosis with more than one symbiont is uncommon, and most genomic studies focusing on such ‘dual symbiosis’ systems have not investigated the host and the symbionts to a similar depth simultaneously. Here, we report a novel dual symbiosis among the peltospirid snail Gigantopelta aegis and its two Gammaproteobacteria endosymbionts – one being a sulphur oxidiser and the other a methane oxidiser. We assembled high-quality genomes for all three parties of this holobiont, with a chromosome-level assembly for the snail host (1.15 Gb, N50 = 82 Mb, 15 pseudo-chromosomes). In-depth analyses of these genomes reveal an intimate mutualistic relationship with complementarity in nutrition and metabolic codependency, resulting in a system highly versatile in transportation and utilisation of chemical energy. Moreover, G. aegis has an enhanced immune capability that likely facilitates the possession of more than one type of symbiont. Comparisons with Chrysomallon squamiferum, another chemosymbiotic snail in the same family but only with one sulphur-oxidising endosymbiont, show that the two snails’ sulphur-oxidising endosymbionts are phylogenetically distant, agreeing with previous results that the two snails have evolved endosymbiosis independently and convergently. Notably, the same capabilities of biosynthesis of specific nutrition lacking in the host genome are shared by the two sulphur-oxidising endosymbionts of the two snail genera, which may be a key criterion in the selection of symbionts by the hosts.


Author(s):  
Eve C. Southward

Prokaryote organisms, with characteristics of Gram-negative bacteria, occur intracellularly in Pogonophora, as described here for seven small species. The tissue containing the bacteria lies between the two longitudinal blood vessels in the posterior part of the trunk and has a special blood supply. This tissue is probably homologous with the so-called trophosome tissue of the much larger vestimentiferan pogonophores, which also contains bacteria, and the term can be applied to all pogonophores. The presence of such bacteria-containing trophosome tissue may be a characteristic of the phylum. In both large and small species examined the bacteria appear to be chemoautotrophs and probably assist the nutrition and/or metabolism of their hosts. It is not yet certain if the bacterium-containing cells do originate from mesoderm or endoderm, but, if the latter, then the trophosome represents the remains of the missing gut. The trophosome tissue situated internally, and transfer of bacteria must take place early in the life history, in the egg or embryo.


2016 ◽  
Vol 283 (1844) ◽  
pp. 20162337 ◽  
Author(s):  
Steffen Kiel

Deep-sea hydrothermal vents and methane seeps are inhabited by members of the same higher taxa but share few species, thus scientists have long sought habitats or regions of intermediate character that would facilitate connectivity among these habitats. Here, a network analysis of 79 vent, seep, and whale-fall communities with 121 genus-level taxa identified sedimented vents as a main intermediate link between the two types of ecosystems. Sedimented vents share hot, metal-rich fluids with mid-ocean ridge-type vents and soft sediment with seeps. Such sites are common along the active continental margins of the Pacific Ocean, facilitating connectivity among vent/seep faunas in this region. By contrast, sedimented vents are rare in the Atlantic Ocean, offering an explanation for the greater distinction between its vent and seep faunas compared with those of the Pacific Ocean. The distribution of subduction zones and associated back-arc basins, where sedimented vents are common, likely plays a major role in the evolutionary and biogeographic connectivity of vent and seep faunas. The hypothesis that decaying whale carcasses are dispersal stepping stones linking these environments is not supported.


Zootaxa ◽  
2012 ◽  
Vol 3241 (1) ◽  
pp. 35 ◽  
Author(s):  
TOMOYUKI KOMAI ◽  
SHINJI TSUCHIDA ◽  
MICHEL SEGONZAC

Five species of the hippolytid shrimp genus Lebbeus White, 1847 are reported from various deep-water hydrothermal ventsites in the Pacific Ocean: L. laurentae Wicksten, 2010 from the East Pacific Rise 13°N; L. wera Ahyong, 2009 from theBrothers Seamount, Kermadec Ridge, New Zealand; L. pacmanus sp. nov. from the Manus Basin, Bismarck Sea; L.shinkaiae sp. nov. from the Okinawa Trough, Japan; and L. thermophilus sp. nov. from the Manus and Lau basins, south-western Pacific. Lebbeus laurentae is fully redescribed because the original and subsequent descriptions are not totallydetailed. Differentiating characters among the three new species and close allies are discussed. Previous records of Lebbeus species from hydrothermal vents are reviewed.


2002 ◽  
Vol 68 (9) ◽  
pp. 4613-4622 ◽  
Author(s):  
Christopher Rathgeber ◽  
Natalia Yurkova ◽  
Erko Stackebrandt ◽  
J. Thomas Beatty ◽  
Vladimir Yurkov

ABSTRACT Deep-ocean hydrothermal-vent environments are rich in heavy metals and metalloids and present excellent sites for the isolation of metal-resistant microorganisms. Both metalloid-oxide-resistant and metalloid-oxide-reducing bacteria were found. Tellurite- and selenite-reducing strains were isolated in high numbers from ocean water near hydrothermal vents, bacterial films, and sulfide-rich rocks. Growth of these isolates in media containing K2TeO3 or Na2SeO3 resulted in the accumulation of metallic tellurium or selenium. The MIC of K2TeO3 ranged from 1,500 to greater than 2,500 μg/ml, and the MIC of Na2SeO3 ranged from 6,000 to greater than 7,000 μg/ml for 10 strains. Phylogenetic analysis of 4 of these 10 strains revealed that they form a branch closely related to members of the genus Pseudoalteromonas, within the γ-3 subclass of the Proteobacteria. All 10 strains were found to be salt tolerant, pH tolerant, and thermotolerant. The metalloid resistance and morphological, physiological, and phylogenetic characteristics of newly isolated strains are described.


2013 ◽  
Vol 280 (1770) ◽  
pp. 20131876 ◽  
Author(s):  
Elizabeth Borda ◽  
Jerry D. Kudenov ◽  
Pierre Chevaldonné ◽  
James A. Blake ◽  
Daniel Desbruyères ◽  
...  

Since its description from the Galapagos Rift in the mid-1980s, Archinome rosacea has been recorded at hydrothermal vents in the Pacific, Atlantic and Indian Oceans. Only recently was a second species described from the Pacific Antarctic Ridge. We inferred the identities and evolutionary relationships of Archinome representatives sampled from across the hydrothermal vent range of the genus, which is now extended to cold methane seeps. Species delimitation using mitochondrial cytochrome c oxidase subunit I (COI) recovered up to six lineages, whereas concatenated datasets (COI, 16S, 28S and ITS1) supported only four or five of these as clades. Morphological approaches alone were inconclusive to verify the identities of species owing to the lack of discrete diagnostic characters. We recognize five Archinome species, with three that are new to science. The new species, designated based on molecular evidence alone, include: Archinome levinae n. sp., which occurs at both vents and seeps in the east Pacific, Archinome tethyana n. sp., which inhabits Atlantic vents and Archinome jasoni n. sp., also present in the Atlantic, and whose distribution extends to the Indian and southwest Pacific Oceans. Biogeographic connections between vents and seeps are highlighted, as are potential evolutionary links among populations from vent fields located in the east Pacific and Atlantic Oceans, and Atlantic and Indian Oceans; the latter presented for the first time.


2021 ◽  
Author(s):  
Daan R Speth ◽  
Feiqiao B Yu ◽  
Stephanie A Connon ◽  
Sujung Lim ◽  
John S Magyar ◽  
...  

Hydrothermal vents have been key to our understanding of the limits of life, and the metabolic and phylogenetic diversity of thermophilic organisms. Here we used environmental metagenomics combined with analysis of physico-chemical data and 16S rRNA amplicons to characterize the diversity, temperature optima, and biogeographic distribution of sediment-hosted microorganisms at the recently discovered Auka vents in the Gulf of California, the deepest known hydrothermal vent field in the Pacific Ocean. We recovered 325 metagenome assembled genomes (MAGs) representing 54 phyla, over 1/3 of the currently known phylum diversity, showing the microbial community in Auka hydrothermal sediments is highly diverse. Large scale 16S rRNA amplicon screening of 227 sediment samples across the vent field indicates that the MAGs are largely representative of the microbial community. Metabolic reconstruction of a vent-specific, deeply branching clade within the Desulfobacterota (Tharpobacteria) suggests these organisms metabolize sulfur using novel octaheme cytochrome-c proteins related to hydroxylamine oxidoreductase. Community-wide comparison of the average nucleotide identity of the Auka MAGs with MAGs from the Guaymas Basin vent field, found 400 km to the Northwest, revealed a remarkable 20% species-level overlap between vent sites, suggestive of long-distance species transfer and sediment colonization. An adapted version of a recently developed model for predicting optimal growth temperature to the Auka and Guaymas MAGs indicates several of these uncultured microorganisms could grow at temperatures exceeding the currently known upper limit of life. Extending this analysis to reference data shows that thermophily is a trait that has evolved frequently among Bacteria and Archaea. Combined, our results show that Auka vent field offers new perspectives on our understanding of hydrothermal vent microbiology.


Zootaxa ◽  
2019 ◽  
Vol 4590 (2) ◽  
pp. 270 ◽  
Author(s):  
ARTEM M. PROKOFIEV ◽  
CYNTHIA KLEPADLO

Two new species of the mesopelagic genus Photonectes are described from the Pacific Ocean. Both of them are characterized by the presence of blue luminous tissue on the body. Photonectes cyanogrammicus new species, is characterized by the unique shape of the mental barbel, expanded distally and lacking bulbs or appendages. It is presently known only from the holotype collected in the Solomon Sea. Photonectes sphaerolampas new species, is described from four specimens collected in the western and central Pacific. It can be easily distinguished from the other species by the presence of the large spherical bulb of the mental barbel with darkly pigmented terminal appendage, split at its tip into several short filaments. Photonectes mirabilis Parr, 1927 is re-described, based on four specimens from the Atlantic and Pacific Oceans; details of jaw dentition and arrangement of the luminous tissue for this species are specified. A key for identification of the species of Photonectes with blue luminous tissue on the body is provided.


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