[Evolutionary regularities of somatic polyploidy manifestation in salivary glands of gastropod molluscs. I. Subclasses Cyclobranchia and 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.
Ziumchenko
N E
NE
Chair of Cytology and Histology, Far East State University, Vladivostok.
Anisimov
A P
AP
D000818:Animals; D005075:Biological Evolution; D008974:Mollusca; D011123:Polyploidy; D012469:Salivary Glands / Q000502:physiology*