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At least 19 recordsLinked to original sources
PubMed1979

Aspartic acid-rich proteins: major components of the soluble organic matrix of mollusk shells.

DEAE-cellulose ion-exchange chromatography separates soluble organic matrix components of three mollusk shells, each from a different taxonomic class, into analogous subfractions. The proteins of all subfractions are enriched in acidic and polar amino acids. In each chromatogram, however, the subfraction which contains the major portion of total protein also contains the highest concentration of aspartic acid. Thus the major components of the soluble organic matrix are aspartic acid-rich proteins. The identification of these proteins in mollusks, together with the known occurrence of aspartic acid and phosphoserine-rich proteins in vertebrate tooth dentin, emphasizes the fundamental importance of such acidic proteins in the processes of mineralization.

Amino Acids↗
PubMed1978

Tumor induction by N-nitroso compounds in bivalve mollusks Unio pictorum.

Diethylnitrosamine (DENA) and dimethylnitrosamine (DMNA) dissolved in tank water induced neoplasms in bivalve mollusks Unio pictorum. DENA induced tumors in 18% of the animals exposed to 200 ppm and 68% of those exposed to 400 ppm; average latent periods were 71 and 61 days, respectively. DMNA induced tumors in 8% of the animals exposed to 200 ppm for 51 days and 27% of those exposed for 152 days with average latent periods of 85 and 81 days, respectively. Neoplasms were observed in the digestive gland (basophilic cell tumors; 38 cases), the hemopoietic system (hemocytoblastosis; 12 cases) and the kidney (poorly differentiated carcinoma; 1 case). It is expedient to use mollusks, both for testing of N-nitroso compounds and as a biologic indicator of hydrospheric pollution.

Animals↗
PubMed1976

Characterization of 80-million-year-old mollusk shell proteins.

Fossil glycoproteins of the soluble organic matrix are present in an 80-million-year-old mollusk shell from the Late Cretaceous Period. Discrete molecular weight components, as determined by gel electrophoresis, are preserved. The fossil organic matrix was compared with the organic matrix of a living representative species of the same superfamily. A particular repeating amino acid sequence, found in contemporary mollusk shell proteins, was identified in the fossil glycoproteins. The ultrastructure, mineralogy, and chemistry of the inorganic components of the fossil and contemporary shells provide information on the state of preservation of the fossil. The use of fossil shell proteins to further our understanding of molecular evolution is discussed.

Amino Acids↗
PubMed1977

Hydrogen peroxide induces spawning in mollusks, with activation of prostaglandin endoperoxide synthetase.

Addition of hydrogen peroxide to seawater causes synchronous spawning in gravid male and female abalones, and certain other mollusks as well. This effect is blocked by exposure of the animals to aspirin, an inhibitor of the enzyme catalyzing oxidative synthesis of prostaglandin endoperoxide. Hydrogen peroxide activates this enzymatic reaction in cell-free extracts prepared from abalone eggs (a very rich source of the prostaglandin endoperoxide synthetase); this effect appears to reveal a fundamental property of prostaglandin endoperoxide synthesis. Applicability of these findings to both mariculture and medical purposes is suggested.

Animals↗
PubMedDate not supplied

[Isolation of the cercaria Diplostomum phoxini (Faust, 1918) Arvy et Buttner, 1954 (Diplostomatidae) from fresh water mollusks of the Crimea].

Data on the biology and morphology of cercariae of Diplostomum phoxini (Faust, 1918) Arvy et Buttner, 1954 are given. The cercariae were found in Radix auricularia from the middle part of the Burulcha river (Ukranian SSR, Crimea). In November, 1974 the invasion extensity of mollusks was 16.3%. No cercariae were found in spring and summer samples.

Fresh Water↗
PubMed2025

Chromosome-level genome assembly of bivalve mollusk, Xishishe Coelomactra antiquata.

Coelomactra antiquata, a significant marine economic shellfish in China, is experiencing a natural population decline due to habitat destruction and overfishing, making the restoration and conservation of its natural resources an urgent priority. This study provides a high - quality chromosome - level genome assembly for C. antiquata, created by PacBio and Hi - C sequencing and resulting in a 19 - chromosome map. The assembly encompasses a genome size of 807.31 Mb, with a contig N50 of 17.35 Mb and a scaffold N50 of 42.90 Mb. A total of 28,070 protein - coding genes were identified, 25,959 of which were functionally annotated. Overall, this study offers a chromosome - level genome for C. antiquata that is highly continuous and complete, providing an indispensable resource for subsequent molecular and genetic studies of this species.

Animals↗
PubMed1976

[Isolation of carotenoid-containing subcellular structures from mollusk nerve tissue].

A subcellular fraction with a high share of carotenoids (about 150 mkg/mg of protein) was obtained from the nerve tissue of Lymnaea stagnalis, the fractionation being made by sucrose density gradient centrifugation. The quantity of carotenoids extracted from fractions was estimated spectrophotometrically. The electron microscope observations demonstrated the presence of structures analogous to fraction components in the mollusc neurones and similar to some kinds of plant chromplasts (carotenoidplasts).

Animals↗
PubMedDate not supplied

[Glycogen synthetase and fructose diphosphatase activity in the tussues of mollusks (Mytilus galloprovincialis) and crustacenas (Balanus improvisus, Carcinus maenas)].

The level of the activity of the enzymes studied is rather similar in all the species investigated, being the highest in muscles and gills. Seasonal changes in the activity of the enzymes in mussel tissues are closely related to reproductive periods and reflect changes in the level of glycogen synthesis.

Animals↗