Mucus Glycoproteins Selectively Secreted from Bacteriocytes in Gill Filaments of the Deep-Sea Clam &lt;i&gt;Calyptogena okutanii&lt;/i&gt;

Five species of parasitic copepods are described based on the material collected during cruise 16 of R/V Anton Bruun. They are: from the gill chambers of macrourids, Chondracanthodes deflexus Wilson, Lateracanthus quadripedis Kabata and Gusev and Brachiella annulata Markevitch; from the anal fin of a macrourid, Nudiclavella galapagoense gen.nov., sp.nov.; and from the gill filaments of brotulids, Naobranchia maxima sp.nov. All fishes were caught with FVSL (free vehicle set lines) in the deep sea off the Galápagos Islands, ranging from 1710 to 3330 m.

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High rates of apoptosis visualized in the symbiont-bearing gills of deep-sea Bathymodiolus mussels

10.1101/422840 ◽

2018 ◽

Author(s):

Piquet Bérénice ◽

Shillito Bruce ◽

H. Lallier François ◽

Duperron Sébastien ◽

C. Andersen Ann

Keyword(s):

Deep Sea ◽

Hydrothermal Vents ◽

Distribution Patterns ◽

Similar Distribution ◽

Cold Seeps ◽

Gill Cells ◽

Mid Atlantic Ridge ◽

Gill Filaments ◽

Specimen Recovery ◽

Active Caspase

AbstractSymbiosis between Bathymodiolus and Gammaproteobacteria enables these deep-sea mussels to live in toxic environments like hydrothermal vents and cold seeps. The quantity of endosymbionts within the gill-bacteriocytes appears to vary according to the hosts environment. We investigated the hypothesis of a control of the endosymbionts density by apoptosis, a programmed cell death. We used fluorometric TUNEL-method and active Caspase-3-targeting antibodies to visualize and quantify apoptotic cells in mussel gills. To avoid artefacts due to depressurization upon specimen recovery from the deep-sea, we compared the apoptotic rates between mussels recovered unpressurised, versus mussels recovered in a pressure-maintaining device, in two species from hydrothermal vents on the Mid-Atlantic Ridge: Bathymodiolus azoricus and B. puteoserpentis. Our results show that pressurized recovery had no significant effect on the apoptotic rate in the gill filaments. Apoptotic levels were highest in the ciliated zone and in the circulating hemocytes, compared to the bacteriocyte zone. Apoptotic gill-cells in B. aff. boomerang from the pockmarks off the Gulf of Guinea, show similar distribution patterns. Deep-sea symbiotic mussels have much higher rates of apoptosis in their gills than the coastal mussel Mytilus edulis without chemolithoautotrophic symbionts. We discuss how apoptosis might be one of the mechanisms that contribute to the adaptation of deep-sea mussels to toxic environments and/or to symbiosis.

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Status of the genus Dallicordia and composition of deep-sea carnivorous bivalves of the genus Policordia (Bivalvia, Verticordioidea, Lyonsiellidae)

Ruthenica, Russian Malacological Journal ◽

10.35885/ruthenica.2021.30(3).5 ◽

2020 ◽

Vol 30 (3) ◽

pp. 173-182

Author(s):

Lyudmila A. Safonova ◽

Elena M. Krylova

Keyword(s):

Deep Sea ◽

New Genus ◽

Intermediate Stage ◽

Undescribed Species ◽

Bivalve Molluscs ◽

Current State ◽

The Family ◽

Gill Filaments ◽

Anatomical Characters ◽

First Time

The family Lyonsiellidae comprises carnivorous bivalve molluscs, distributed worldwide from sublittoral to ultraabyssal depths. One of the key anatomical characters of lyonsiellids is the reduction of the gill filaments in size and number and an increase of amount of muscles and connective tissue in gills, so their ctenidia represent an intermediate stage between eulamellibranch and septibranch conditions. The family Lyonsiellidae presently includes four genera: Lyonsiella, Allogramma, Policordia and Dallicordia. Taxonomy of the family is still problematic at both generic and species levels. The genus Dallicordia, typified by Lyonsiella alaskana was established on the assumption that it has no gills but possesses a muscular septum pierced by ostia, in contrast to the other lyonsiellids that have filamentous gills. Additionally, Lyonsiella uschakovi and Policordia ochotica were tentatively assigned to the new genus. Later P. ochotica was synonymized with P. media. In this paper we show that actually the Dallicordia was typified by an undescribed species misidentified as Lyonsiella alaskana which we describe here as D. bernardi sp. nov. Taxonomic position of the genus is dubious and could be clarified only after additional anatomical data on its type species becomes available. On the basis of examination of the type material of P. ochotica and images of the holotype of P. media, we reinstate the species P. ochotica. For the first time photographs of the holotype of L. uschakovi are provided for this specimen that was previously considered lost. Given the current state of knowledge we propose to consider species L. alaskana, L. uschakovi and P. ochotica in frame of the genus Policordia, for which we provide a list of all 29 species described up to date.

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The structure of the gills of the axolotl, Ambystoma mexicanum

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128407 ◽

1987 ◽

Vol 45 ◽

pp. 824-825

Author(s):

Mohinder S. Jarial

Keyword(s):

Leydig Cells ◽

Secretory Granules ◽

Light And Electron Microscopy ◽

Cell Types ◽

Ambystoma Mexicanum ◽

Basal Cells ◽

Granular Cells ◽

Gill Filaments ◽

Mitotic Figures ◽

Apical Membranes

The axolotl is a strictly aquatic salamander in which the larval external gills are retained throughout life. The external gills of the adult axolotl have been studied by light and electron microscopy for ultrastructural evidence of ionic transport. The thin epidermis of the gill filaments and gill stems is composed of 3 cell types: granular cells, the basal cells and a sparce population of intervening Leydig cells. The gill epidermis is devoid of muscles, and no mitotic figures were observed in any of its cells.The granular cells cover the gill surface as a continuous layer (Fig. 1, G) and contain secretory granules of different forms, located apically (Figs.1, 2, SG). Some granules are found intimately associated with the apical membrane while others fuse with it and release their contents onto the external surface (Fig. 3). The apical membranes of the granular cells exhibit microvilli which are covered by a PAS+ fuzzy coat, termed “glycocalyx” (Fig. 2, MV).

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