Cytochemistry of yolk elements in the egg of the tunicate Molgula

Summary Cytochemical techniques demonstrate two types of yolk elements (compound yolk and lipid yolk) in the egg of the tunicate (Molgula manhattensis). The compound yolk elements consisting of proteins, carbohydrates, lipoproteins and triglycerides arise under the influence of cell organelles. A few lipid yolk elements staining moderately for phospholipids are also formed. The distribution and cytochemistry of cell organelles have also been described briefly in growing oocytes, test cells and follicular epithelial cells.     

Balbiani's vitelline body in the oocytes of vitellogenic and nonvitellogenic females of the domestic fowl: a correlative cytological and histochemical study.

A cytological and histochemical study has been made of Balbiani's vitelline body in the oocytes of nonvitellogenic and vitellogenic females of the domestic fowl (Gallus domesticus), which consists of yolk nucleus, mitochondria, Golgi bodies and lipid bodies of diverse nature. The yolk nucleus consisting of RNA, protein and lipoprotein shows the greatest development and morphological complexity in the growing oocytes of vitellogenic females. Its possible significance has been discussed in relation, to the variable metabolism and hormonal status of the female during sexual maturation.     

Morphological and histochemical observations on the ovarian surface epithelium during the reproductive cycle of crow (Corvus splendens) and myna (Acridotheres tristis).

A morphological and histochemical study has been made of ovarian surface epithelium during the sexual cycle of seasonally breeding birds: crow (Corvus splendens) and common myna (Acridotheres tristis). The surface epithelium is composed of a single layer of compactly arranged columnar and flat cells in the quiescent ovary. It develops numerous villi during the breeding season. The formation of villi has been correlated with the proliferation of cells which are subsequently incorporated into the ovarian stroma where they appear to form follicle and thecal cells around the growing oocytes as evidenced by the close similarities in the morphological and histochemical characteristics of these cell types. As the ovarian activity increases, the surface epithelial cells show increasing amounts of RNA and proteins, which are indicative of their rapid multiplication. No lipids and enzyme activities of acid and alkaline phosphatases, ATPase. DPN- and TPN- diaphorases and delta5-3beta HSDH have been detected in the surface epithelium of both quiescent and active ovaries.     

Comparative histochemical observations on the lipids in the immature and mature stages of Cotylophoron cotylophorum Paramphistomatidae: Digenea.

Immature and mature stages of the sheep amphistome Cotylophoron cotylophorum have been analysed histochemically for their lipids. Excretory ducts of the immature worms were the common sites for the accumulation of neutral lipids (triglycerides) and phospholipids which showed very sparse distribution at the corresponding sites in the adult. Phospholipids and lipoproteins observed in the tegument of the adult could not be seen in the immature form. Intestinal caecae of both forms showed the presence of diffused and granular lipids which were relatively less in the immature. The possible physiological significance of these differences in the lipid contents of the immature and mature forms has been discussed.