[Evolutionary regularities of somatic polyploidy expansion in salivary glands of gastropod mollusks. V. Subclasses Opisthobranchia and Pulmonata].

Salivary glands of 25 species of euthyneural gastropod mollusks (Opisthobranchia and Pulmonata) have been investigated by means of histochemical methods and DNA cytophotometry in nuclei of cells. The cells of three basic types are distinguished in glandular epithelim: granular cells (with glicoproteid granular inclusions), mucocytes-I (with sulfatic acid mucopolysaccharides) and mucocytes-II (with neutral and acid nonsulfatic polysaccharides and proteins) and so the epithelial ciliated cells and cells of the ducts. It was shown that glandular cells of salivary glands of all discovered mollusks' species are polyploid in different degree. The highest ploidy level estimated by means of DNA content in most of species is 64-128c. The giant polyploidy, attained to 4096c, is discovered in cells of salivary glands of Tritonia diomedea. The functional conditionality connected with features of feeding of different mollusk species and phylogenetic tendencies of expansion of somatic polyploidy in class Gastropoda are discussed. In comparison with allogenic, facultative and small polyploidy manifestation in Prosobranchia the obligatory polyploidization of high degree revealed in cells of salivary glands of Opisthobranchia and Pulmonata is consider to be the original cytological arogenesis. The probable causes of such differences are conneted with euthyneural type of organization of central nervous system and giant polyploidy of neurons in Opisthobranchia and Pulmonata mollusks. The causes, mechanisms and significance of such correlations are unclear for the present.

[Evolutionary regularities of the somatic polyploidy manifestation in salivary glands of gastropod molluscs. IV. A subclass of Pectinibranchia: Orders Hamiglossa and Toxoglossa (Neogastropoda)]. / Evoliutsionnye zakonomernosti proiavleniia somaticheskoi poliploidii v sliunnykh zhelezakh briukhonogikh molliuskov. IV. Podklass Pectinibranchia: Otriady Hamiglossa i Toxoglossa (Neogastropoda).

Salivary glands of 12 species of carnivorous gastropod molluscs, making the Neogastropoda group have been investigated by histochemical methods and DNA cytophotometry. We studied the anatomical and histological structure of ordinary (acinous) and accessory (tubular) salivary glands, and of unpaired glands (Leiblen's, "framboisée", and poisonous). Cells of three types were distinguished: granular cells (with glycoproteid granular inclusions), mucocytes-I (with sulfatic acid mucopolysaccharides), and epithelial ciliated cells. In ordinary and accessory glands of the studied Neogastropods, polyploid cells with polyploidy levels from 4c to 16c were revealed together with diploid cells. The functional significance and phylogenetic tendencies of polyploidy manifestation in salivary glands of prosobranch gastropods are discussed.

[Evolutionary regularities of the appearance of polyploidy in salivary glands of gastropod mollusks. III. A subclass of Pectinibranchia: Orders Discopoda, Echinospirida, Aspidophora and Entomostoma (Mesogastropoda)]. / Evoliutsionnye zakonomernosti proiavleniia somaticheskoi poliploidii v sliunnykh zhelezakh briukhonogikh molliuskov. III. Podklass Pestinibranchia: otriady Discopoda, Echinospirida, Aspidophora i Entomostoma (Mesogastropoda).

By means of histological methods and DNA cytophotometry, a study was made of the salivary glands of 16 species of gastropod molluscs belonging to the subclass Pectinibranchia and making a group of Mesogastropoda. Four cell types of salivary glands were distinguished: granular cells (with glycoproteid granular inclusions), mucocytes-I (with sulfatic acid mucopolysaccharides), mucocytes-II (with neutral and acid polysaccharides and proteins), and also the epithelial ciliated cells and mucous duct cells. Data of experiments on starvation and synchronous feeding of molluscs have testified that all described cell types are independent. In some species differentiation on protein and mucous departments within the glandular epithelium was shown. In some marine representatives of the orders Discopoda and Aspidophora polyploid cells with the ploidy levels from 8c to 32c were revealed along with diploid cells. The ecological and phylogenetic regularities of somatic polyploidy manifestation in Mesogastropoda are discussed.

[Evolutionary regularities of somatic polyploidy in salivary glands of the Gastropod molluscs. II. Subclass Pectinibranchia: order Anisorbranchia]. / Evoliutsionnye zakonomernosti proiavleniia somaticheskoi poliploidii v sliunnykh zhelezakh briukhonogikh molluskov. II.Podklass Pectinibranchia: otriad Anisorbranchia.

Salivary glands of 5 species of gastropod molluscs of the order Anisobranchia, the most ancient order within the subclass Pectinibranchia, have been investigated by histological and cytochemical methods, including DNA cytophotometry. Glandular cells of the following types were recognized: granular cells (with glycoproteid granular inclusions), mucocytes-I (including sulfatic acid mucopolysaccharides), mucocytes-II (including neutral and acid polysaccharides and proteins), and epithelial ciliated cells. All the described cell types are considered to be independent and their morphofunctional characteristics coincide with those of salivary gland cells of the gastropod molluscs of subclasses Cyclobranchia and Scutibranchia. It has been shown that somatic polyploidy in salivary glands in the Anisobranchia molluscs, likely as in those of other Archaeogastropoda (Cyclobranchia and Scutibranchia), is actually absent.

[Evolutionary regularities of somatic polyploidy manifestation in salivary glands of gastropod molluscs. I. Subclasses Cyclobranchia and Scutibranchia]. / Evoliutsionnye zakonomernosti proiavleniia somaticheskoi poliploidii v sliunnykh zhelezakh briukhonogikh molluskov. I. Podklassy Cyclobranchia i Scutibranchia.

By means of histological and cytochemical methods, including DNA cytophotometry, the salivary glands of 11 species of molluscs of two old gastropod subclasses--Cyclobranchia and Scutibranchia (limpets)--have been investigated. In spite of some anatomical differences, the glandular epithelium of investigated molluscs includes functionally similar cell types: granular cells (with glycoproteid granular inclusions), mucocytes-I (that include sulfatic acid mucopolysaccharides), mucocytes-II (that include neutral and acid polysaccharides and proteins) and also the epithelial ciliated cells. Data of experiments on starvation and synchronous feeding of molluscs testify that all described cell types are independent. According to DNA cytophotometry data, the glandular cell nuclei are diploid in the main; only small part of the nuclei, varying in different species from 0.5 to 5.0%, displayed tetraploid DNA mass. A conclusion is made that in the oldest subclasses of gastropods (Cyclobranchia and Scutibranchia) somatic polyploidy, as a factor of tissue growth in salivary glands, is actually absent.