EVOLUTIONARY REGULARITIES OF SOMATIC POLYPLOIDY EXPANSION IN SALIVARY
GLANDS OF GASTROPOD MOLLUSKS. V. SUBCLASSES OPISTHOBRANCHIA AND PULMONATA
A.P. Anisimov,1 N.E. Zyumchenko
Far Eastern Federal University, Vladivostok;
1 e-mail: alim@bio.dvgu.ru
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.
Key words: salivary glands, DNA content, somatic polyploidy, endopolyploidy, Gastropoda
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