Histochemistry of glycoconjugates in the gallbladder epithelium of ten animal species

Summary A battery of seven lectins and several conventional mucin histochemical techniques were used to identify the epithelial mucins of the gallbladder of ten species: man, rabbit (Oryctolagus cuniculus, mammalia), hamster (Mesocricetus auratus, mammalia), chicken (Gallus gallus, bird), sparrow (Passer domesticus, bird), moorish gecko (Tarentola mauritanica, reptilia), ladder snake (Elaphe scalaris, reptilia), lake frog (Rana perezi, amphibia), natterjack toad (Bufo calamita, amphibia) and gilthead sea bream (Sparus auratus, fish). Glycogen was found in the epithelial lining of the reptilian and amphibian gallbladders. Sulphate and carboxyl groups were frequently found in the same species, except in the ladder snake and natterjack toad gallbladders where only sulphate groups were identified. Sialic acid residues were detected in man, rabbit, bird, T. mauritanica, R. perezi and fish gallbladders. ConA binding pattern was similar in the ten species studied. In the human gallbladder only PNA failed to label the luminal surface, while the glands were only unreactive to DBA. The human gallbladder showed a large variety of saccharides. The present results suggest that no relation exists between the composition of the gallbladder mucins and the situation of the species in the phylogenetic scale.     

Histochemistry of glycoconjugates in the gallbladder epithelium of ten animal species

A battery of seven lectins and several conventional mucin histochemical techniques were used to identify the epithelial mucins of the gallbladder of ten species: man, rabbit (Oryctolagus cuniculus, mammalia), hamster (Mesocricetus auratus, mammalia), chicken (Gallus gallus, bird), sparrow (Passer domesticus, bird), moorish gecko (Tarentola mauritanica, reptilia), ladder snake (Elaphe scalaris, reptilia), lake frog (Rana perezi, amphibia), natterjack toad (Bufo calamita, amphibia) and gilthead sea bream (Sparus auratus, fish). Glycogen was found in the epithelial lining of the reptilian and amphibian gallbladders. Sulphate and carboxyl groups were frequently found in the same species, except in the ladder snake and natterjack toad gallbladders where only sulphate groups were identified. Sialic acid residues were detected in man, rabbit, bird, T. mauritanica, R. perezi and fish gallbladders. ConA binding pattern was similar in the ten species studied. In the human gallbladder only PNA failed to label the luminal surface, while the glands were only unreactive to DBA. The human gallbladder showed a large variety of saccharides. The present results suggest that no relation exists between the composition of the gallbladder mucins and the situation of the species in the phylogenetic scale.     

Ultrastructure of the developing gizzard epithelium in the chick embryo

Summary The fine structure of the gizzard epithelium is described at different stages in the development of the chick embryo. The elaborate apical processes, a characteristic feature, take part in secretion at thirteen days, but do not seem to have this function at nine and ten days. The formation of glands begins at thirteen days but the adult fine structure of the gland cells is not attained until hatching. The distinct surface layer present between thirteen and seventeen days may have a protective function.Acknowledgement. The author is grateful for research facilities provided by Professor G. M. Wyburn, Anatomy Department, The University of Glasgow.     

The development of melanosomes in the pigment epithelium of the chick embryo

Summary The origin of the melanosome in the pigment epithelium of the chick embryo was studied by electron microscopy and cytochemistry of tyrosinase. The melanosome appears first at stage 16 in the dorso-caudal region of the optic cup and the first appearance of the tyrosinase activity can also be detected at the same stage in Golgi sac. At the early stages, premelanosomes and amorphous, electron dense granules which are considered to be the developing premelanosomes appear as a group at the basal region of the outer layer cell. The membrane of these granules is connected with that of ER. Attention should be paid to the fact that there are tyrosinase-negative premelanosomes, even when Golgi sac and Golgi vesicles are tyrosinase-positive. According to these facts it can be said that the site of origin of premelanosomes are not Golgi vesicles, but the smooth-surfaced ER connected with the rough-surfaced ER, and that the tyrosinase is transported to premelanosomes by tyrosinase-containing vesicles which originate from matured Golgi sac.The author is grateful to Prof. Dr. Junnosuke Nakai for his encouragement and valuable suggestions. Thanks are also due to Prof. Dr. Eichi Yamada and Prof. Dr. Shiro Igarashi for their comments on the electron-microscopic study.     

Collagen production in vitro by the retinal pigmented epithelium of the chick embryo

Cloned colonies and explants of embryonic chick retinal pigmented epithelium from donors of various embryonic ages were maintained in culture for different periods and examined by electron microscopy. The cells appeared morphologically differentiated and polarized. Basement-membrane material and striated collagen fibrils were identified as extracellular deposits beneath the basal surfaces of the cells. There appeared to be a distinct spatial and temporal correlation between the production of basement-membrane material and collagen fibrils. Increasing donor age correlated positively with increasing average diameter of the collagenous fibrils produced, as well as a widening of the range of fibril sizes.     

Ultrastructural differentiation of the epithelium and mucous glands of the esophagus in the chick embryo

Esophagi of White Leghron chick embryos, six days to hatching, were fixed in 5% glutaraldehyde in a cacodylate-sucrose buffer, postfixed in 1% OsO₄, dehydrated and embedded in Araldite. Tissues were sectioned with glass knives and viewed with a Philips EM 100C. The epithelium in early stages of development is characterized by small intercellular spaces, few cell processes and few desmosomes. In contrast the differentiated epithelium contains numerous cell processes, large intercellular spaces and numerous desmosomes. Mucin appeared in the mucous glands at 17 days.     

Electron histochemistry of mucosubstances in normal human rectal epithelium

Synopsis The electron microscopic histochemistry of mucosubstances in sigmoidoscopically and microscopically normal rectal biopsies was studied using techniques currently available. The deposition of Alcian Blue and Ruthenium Red and the distribution of Concanavalin A receptors were limited to the epithelial cell borders. Mucosubstances in the fuzzy coat, Golgi apparatus, lysosomes and secretory vesicles were demonstrated by the periodic acid—chromic acid oxidation methods. Glycogen was demonstrated in the epithelium by periodate oxidation methods and the complex cyanide technique. There was little difference in the distribution of mucosubstances in the epithelial cells at any level of the crypts. Phosphotungstic acid staining under controlled conditions gave a similar distribution of mucosubstances to those revealed by the oxidation techniques.