Enzymologie du tractus digestif de la modiole hydrothermale Bathymodiolus thermophilus (Mollusque Bivalve)

1992 ◽  
Vol 70 (12) ◽  
pp. 2298-2302 ◽  
Author(s):  
Marcel Le Pennec ◽  
Jean-Claude Martinez ◽  
Anne Donval ◽  
Angèle Herry ◽  
Peter Beninger
Keyword(s):  
Digestive Tract ◽  
Digestive Gland ◽  
Hydrothermal Vent ◽  
Digestive Enzyme ◽  
Nutrient Supply ◽  
Enzyme Assays ◽  
Bathymodiolus Thermophilus ◽  
Intracellular Digestion ◽  
Chemoautotrophic Bacteria ◽  
Structure And Ultrastructure

Although the structure and ultrastructure of the digestive tract of the hydrothermal vent mytilid Bathymodiolus thermophilus conform to those of other bivalves, enzymological data are lacking. To address this question, digestive enzyme assays and histoenzymological tests were performed on different regions of the digestive tract: labial palps, oesophagus, stomach, digestive gland, intestine, and rectum. Carbohydrases, mainly present in the digestive gland and the stomach, were the most active of the 33 enzymes studied. These enzymes would allow substantial digestion of particles from the immediate environment as well as those descending from the photic zone. Acid phosphatases present in all the compartments of the digestive tract indicate intracellular digestion, whereas alkaline phosphatase activity, mainly in the digestive gland and the stomach, demonstrates absorption phenomena. We conclude that, in addition to the nutrient supply furnished by chemoautotrophic bacteria in the gill bacteriocytes, the digestive tract is functional and provides at least some of the nutritive requirements of this species.

Aspects of the feeding biology of the pectinacean Bathypecten vulcani, a peri-hydrothermal vent bivalve

2003 ◽  
Vol 83 (3) ◽  
pp. 479-482 ◽  
Author(s):  
Gaël LE PENNEC ◽  
Peter G. BENINGER ◽  
Marcel LE PENNEC ◽  
Anne DONVAL
Keyword(s):  
Digestive Tract ◽  
Hydrothermal Vent ◽  
Stomach Contents ◽  
Frontal Surface ◽  
Mineral Particles ◽  
East Pacific ◽  
Feeding Biology ◽  
Crystalline Style ◽  
Bathymodiolus Thermophilus ◽  
Cytological Characteristics

The feeding biology of Bathypecten vulcani, a peri-hydrothermal vent pectinacean, was investigated using histological and scanning electron microscope studies of the gills and stomach contents of specimens sampled from the 9° and 13°N sites of the East Pacific Rise. Salient characteristics were compared with those of Bathymodiolus thermophilus from the same and similar habitats. The gills of Bathypecten vulcani displayed heterogeneous organic and mineral particles on their frontal surface. The digestive tract possessed well-developed structures (whose anatomical and cytological characteristics indicated full functionality), typically found in bivalves from littoral aerobic environments, as well as in Bathymodiolus thermophilus, which is capable of suspension-feeding: oesophagus, stomach, crystalline style, digestive gland, and intestine. Observations of stomach contents revealed diverse particles from the photic zone, including debris from diatoms and coccolithophorans. In contrast to Bathymodiolus thermophilus, bacteria were rarely observed in the digestive tract, indicating a more complete reliance on surface-originating particles.

Ultrastructural characteristics of spermatogenesis in three species of deep-sea hydrothermal vent mytilids

1997 ◽  
Vol 75 (2) ◽  
pp. 308-316 ◽  
Author(s):  
Marcel Le Pennec ◽  
Peter G. Beninger
Keyword(s):  
Deep Sea ◽  
Hydrothermal Vent ◽  
The North ◽  
Male Gametes ◽  
Bathymodiolus Thermophilus ◽  
Nutritional Biology ◽  
Protandric Hermaphroditism ◽  
Mid Atlantic Ridge ◽  
Ultrastructural Characteristics ◽  
Species Specific

To enhance our understanding of the reproductive biology of deep-sea hydrothermal vent mytilids, the histology of the male gonad and the ultrastructure of its gametes were studied in Bathymodiolus thermophilus, B. puteoserpentis, and B. elongatus. Specimens of B. thermophilus were collected at the 13°N site on the East Pacific ridge, while B. puteoserpentis were sampled from the Snake Pit site of the mid-Atlantic ridge and B. elongatus were obtained from the North Fiji Basin. Gonad histology conformed to the typical bivalve profile; the differences in the proportions of acinal and interacinal tissue, as well as differences in acinal fullness in B. puteoserpentis, indicate that gametogenesis is discontinuous in these deep-sea mytilids. Evidence of protandric hermaphroditism was observed in B. elongatus, which exhibited acini containing both maturing and residual male gametes and immature oocytes. The ultrastructural characteristics of the male gametes conform to those described for littoral bivalve species, and the spermatozoon is of the primitive type. No species-specific differences in spermatozoon ultrastructure were discerned. No evidence of bacterial inclusions was found in either the gametes or the associated gonad cells in any of the species examined. The male gametes are thus probably not vectors for the endosymbiotic bacteria that characterize the nutritional biology of the adults in this genus.

scholarly journals Evolution of self-limited cell division of symbionts

2019 ◽  
Vol 286 (1895) ◽  
pp. 20182238 ◽  
Author(s):  
Yu Uchiumi ◽  
Hisashi Ohtsuki ◽  
Akira Sasaki
Keyword(s):  
Cell Division ◽  
Death Rate ◽  
Nutrient Supply ◽  
Arms Race ◽  
Evolutionary Transition ◽  
Division Rate ◽  
Essential Step ◽  
Intracellular Digestion

In mutualism between unicellular hosts and their endosymbionts, symbiont's cell division is often synchronized with its host's, ensuring the permanent relationship between endosymbionts and their hosts. The evolution of synchronized cell division thus has been considered to be an essential step in the evolutionary transition from symbionts to organelles. However, if symbionts would accelerate their cell division without regard for the synchronization with the host, they would proliferate more efficiently. Thus, it is paradoxical that symbionts evolve to limit their own division for synchronized cell division. Here, we theoretically explore the condition for the evolution of self-limited cell division of symbionts, by assuming that symbionts control their division rate and that hosts control symbionts' death rate by intracellular digestion and nutrient supply. Our analysis shows that symbionts can evolve to limit their own cell division. Such evolution occurs if not only symbiont's but also host's benefit through symbiosis is large. Moreover, the coevolution of hosts and symbionts leads to either permanent symbiosis where symbionts proliferate to keep pace with their host, or the arms race between symbionts that behave as lytic parasites and hosts that resist them by rapid digestion.

Biodiversity Solen sp. in Madura Island

2017 ◽  
Vol 862 ◽  
pp. 115-120
Author(s):  
Eva Ari Wahyuni ◽  
Insafitri ◽  
Mohammad Nur Ihsan ◽  
Gatot Ciptadi
Keyword(s):  
Digestive Gland ◽  
Environmental Parameters ◽  
Clayey Sand ◽  
Intracellular Digestion ◽  
Value Range ◽  
Environment Parameters

Madura Island is one of island in East Java as occupied by Solen sp. Four districts in Madura islands as the producer of Solen sp. Sampang is the biggest area with the largest size. This study aims to determine the morphology and biodiversity of the Solen sp in Madura. The study was conducted at several locations in Madura during the period from May to July 2015. The main sample are Solen sp and environmental parameters (temperature, salinity, pH, and substrate) taken at four locations in Madura i.e. Bangkalan, Sampang, Pamekasan, and Sumenep. The analysis shows the parameter value range is 28-30o C, salinity : 31-33 ppt, pH : 7.9-8.2, dominated by clayey-sand, and rate population is 7-10 individual/cm2. It indicated that Solen sp have supported environment parameters. Mean length of Solen sp is 2-4 inch, elongated and thin, and the lid open with one another. Intracellular digestion takes place in their digestive gland which is composed of ducts, starting in the stomach and ending in blind tubules.

Formation of the gut in the first two naupliar stages of Acartia clausi and Hemidiaptomus roubaui (Copepoda, Calanoida): comparative structural and ultrastructural aspects

2002 ◽  
Vol 80 (2) ◽  
pp. 232-244 ◽  
Author(s):  
A Baud ◽  
R -M Barthélémy ◽  
S Nival ◽  
M Brunet
Keyword(s):  
Epithelial Cells ◽  
Digestive Tract ◽  
Digestive System ◽  
Larval Stages ◽  
Acartia Clausi ◽  
The Future ◽  
Endodermal Cells ◽  
Structure And Ultrastructure

In this study, the structure and ultrastructure of the digestive system are compared in the early larval stages (nauplii I and II) of two copepod calanoid species, Acartia clausi Giesbrecht, 1889 and Hemidiaptomus roubaui Richard, 1888. The nauplii I of both species have no functional digestive tract, which is represented initially only by a blind esophageal slit and yolky endodermal cells, which fill the most part of the naupliar body, whereas at the nauplius II stage the differentiated digestive tract becomes functional. The resorption cavity corresponding to the future midgut is progressively formed in the endodermal mass during the premolt phase; it is surrounded by differentiating epithelial cells. In the ecdysial phase the foregut has associated labral glands, the midgut young R-, B-, and R'-cells of epithelium, and there is a short open hindgut.

Les osidases digestives de l'escargot Helix aspersa: localisations et variations en fonction de l'état nutritionnel

1992 ◽  
Vol 70 (11) ◽  
pp. 2234-2241 ◽  
Author(s):  
Maryvonne Charrier ◽  
Corinne Rouland
Keyword(s):  
Salivary Glands ◽  
Digestive Tract ◽  
Digestive Gland ◽  
Bacterial Flora ◽  
Helix Aspersa ◽  
Similar Distribution ◽  
Synergistic Activity

Osidases were studied in brown garden snails, Helix aspersa Müller, fed or starved for 4 or 7 weeks. The digestive tract was divided into seven regions: oesophagus, crop, stomach, intestine, rectum, salivary glands, and digestive gland. The results revealed the presence of a large number of enzymes that attack alimentary carbohydrates. However, α-heterosides and starch were poorly hydrolysed, and amylase was not derived from saliva. Enzymatic secretions continued in snails subjected to 7 weeks of starvation and accumulated in the stomach, while these enzymes were active mainly in the oesophagus and the crop during nutrition. Several hypotheses are presented, including that the most active enzymes, mannanases and cellulases, may be secreted both by the salivary glands and by the digestive gland. A similar distribution is postulated for two oligosaccharidases, maltase and saccharase. Since a bacterial flora exists in the digestive tract, we also consider the possibility of a synergistic activity between osidases from the snail and those originating from the microflora.

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