Histochemical studies of mucosubstances in the epidermis of a nonscaly teleost Mystus (Mystus) vittatus Bl. (Pisces-Bagridae)

The epidermis of Mystus (Mystus) vittatus contains two well differentiated mucous cells which secrete different mucosubstances. The goblet cells contain periodate reactive neutral mucosubstances, glycogen, testicular hyaluronidase resistant sulphated mucosubstances, and sialic acid rich glycoproteins. The clavate cells contain small amounts of neutral and sulphated mucosubstances and no glycoproteins. The difference in the histochemical nature of the two types of mucous cells is discussed in relation to their physiological activities.     

Histochemistry of mucosubstances in Brunner's-gland cells and duodenal goblet cells of two New World monkey species (Saimiri sciureus andSaguinus fuscicollis)

Summary Duodenal goblet cells and Brunner's-gland cells obtained from two species of New World monkeys (Saimiri sciureus andSaguinus fuscicollis) were studied using conventional histochemical methods and by applying a panel of 17 labelled lectins. The secretions of both goblet and Brunner'-gland cells were found to contain neutral mucosubstances, while those of goblet cells also exhibit acid and sulphated carbohydrate components. Lectin binding studies allowed a more detailed analysis of the mucus glycoproteins. Marked differences between the two examined species were not detected.N-Acetyl-galactosamine, galactose, fucose andN-Acetyl-glucosamine were found to be the predominante sugar residues in Brunner's-glands glycoproteins, with mannose and glucose being only minor components.Dedicated to Professor Dr. T.H. Schiebler on the occasion of his 65th birthday     

Histochemistry of mucosubstances in Brunner's-gland cells and duodenal goblet cells of two New World monkey species (Saimiri sciureus and Saguinus fuscicollis)

Duodenal goblet cells and Brunner's-gland cells obtained from two species of New World monkeys (Saimiri sciureus and Saguinus fuscicollis) were studied using conventional histochemical methods and by applying a panel of 17 labelled lectins. The secretions of both goblet and Brunner's-gland cells were found to contain neutral mucosubstances, while those of goblet cells also exhibit acid and sulphated carbohydrate components. Lectin binding studies allowed a more detailed analysis of the mucus glycoproteins. Marked differences between the two examined species were not detected. N-Acetyl-galactosamine, galactose, fucose and N-Acetyl-glucosamine were found to be the predominant sugar residues in Brunner's-glands glycoproteins, with mannose and glucose being only minor components.     

Carbohydrate histochemistry of the opossum submandibular and major sublingual glands.

Submandibular and major sublingual salivary glands of the opossum contain histochemically demonstrable neutral mucosubstances, nonsulfated acid musosubstances and sulfomucins. Sialomucins could not be demonstrated conclusively with the methods used in this study. Special serous cells of the opossum submandibular gland contained low concentrations of acidic mucosubstances but no appreciable concentration of neutral mucosubstances was seen. Sulfomucins were not observed in special serous cells. The mucous tubules of the submandibular gland contained high concentrations of neutral mucosubstances. No appreciable acidic mucosubstance was demonstrated in the submandibular gland mucous tubules. Unlike the mucous tubules of the submandibular gland, the major sublingual gland mucous tubules contained high concentrations of both neutral and acidic mucosubstances. The mucous tubules often contained sulfomucin-positive cells interspersed among cells that contained high concentrations of non-sulfated acidic mucosubstance. Marked staining of sulfated acidic mucosubstance was seen only in the major sublingual gland, in both the mucous tubules and in the seromucous demilunes. The seromucous demilunes contained both sulfated and non-sulfated acidic mucosubstances.     

Structural and ultrastructural features of boar bulbourethral glands

The morphological features of boar bulbourethral glands were examined by light and transmission microscopy. Bulbourethral glands are compound tubuloalveolar glands surrounded by a capsule of dense connective tissue and arranged in multiple lobules formed by endpieces and excretory ducts. Endpieces and excretory ducts are both lined by a single epithelium of mucous cells with a basal nucleus. Epithelial cells accumulate secretory granules containing neutral and carboxylated acid mucosubstances and a small amount of sulphated acid mucosubstances. The ultrastructure of epithelial cells varies according to the secretory cycle. In initial stages, the cells show a columnar shape and secretory granules unevenly distributed in the cytoplasm. As the synthesis of mucosubstances progresses, the amount of the secretory granules increases and the cellular shape becomes pyramidal. Secretory granules can contain inclusions and present differences among them according to their different phases of formation. In pyramidal cells, secretory products are released into the lumen by a merocrine mechanism.     

Histochemical studies of the colonic epithelial glycoproteins of the normal rabbit

Summary Two general classes of glycoproteins have been identified in the colonic epithelial cells of New Zealand white rabbits. Each is associated with an ultrastructurally distinct secretory cell. The first of these classes is found in cells, termed vesiculated columnar cells, characterized by electron-translucent vesicles, a small rough endoplasmic reticulum-Golgi complex and prominent microvilli. The glycoproteins of the vesiculated cells contain abundantO-sulphate ester, sialic acids with ester substituents at positions C-8 or C-9 (or with two or three side chain substituents) and neutral sugars withvicinal diols whose periodate oxidation is prevented by anO-acyl ester substituent(s). The second class of glycoproteins occurs in goblet cells characterized by electron-dense vesicles, an abundant rough endoplasmic reticulum, a well-developed Golgi apparatus and few, if any, microvilli. Goblet cells along the entire length of the crypts contain neutral sugars with periodate-oxidisablevicinal diols and a ferriferricyanide-reactive component. Cells in the upper halves of the crypts also contain components that are sulphated, Schiff-reactive and acid-fast. In the lower halves of the crypts, the goblet cells contain smaller quantities of the above components plus sialic acids, some of which possibly have anO-acyl substituent located at position C-8 or C-9 (or which have two or three side chainO-acyl substituents). It is suggested that the function of the glycoproteins from the vesiculated columnar cells is protective and that from the goblet cells is lubricative.     

Ultrastructural carbohydrate cytochemistry of gastric epithelium

Synopsis On examination with ultrastructural methods for visualizing thevicinal glycols and acid groups of complex carbohydrates, the most superficial surface epithelium of the rat gastric corpus displayed biphasic mucous droplets consisting of a cortex of hexose-rich (i.e. periodate-reactive) neutral mucosubstance and an uncharacterized denser core plus monophasic droplets with the neutral mucosubstance. In many surface epithelial cells of the foveolae, the biphasic and monophasic droplets with the neutral mucosubstance intermingled in varying proportions with monophasic droplets showing uniform periodate reactivity, a variable degree of dialyzed ironbinding—demonstrative of acidic glycoconjugate, and high iron—diamine affinity—demonstrative of sulphomucin. Deep foveolar epithelium displayed only monophasic droplets, most of which contained acidic periodate-reactive complex carbohydrate. Underiying cells, designated isthmus cells, exhibited monophasic or occasional biphasic granules containing sulphated, hexose-rich mucosubstance. Nascent droplets or granules near the Golgi zone differed from the mature organelles in the distribution of the glycoconjugate. Mucous neck cells occupied a deeper stratum and displayed a uniform population of monophasic mucous droplets with a loose meshwork of neutral mucosubstance.Techniques for demonstrating hexoses ultrastructurally stained all Golgi cisternae in the mucigenic epithelium, showing increasing reactivity toward the maturing face. Distinctive cistemae with moderate reactivity in the Golgi complex of isthmus cells were interpreted as GERL. Acidic mucosubstances were visualized only in the inner, mature cisternae of the Golgi complex of cells storing acidic glycoconjugates, and not in cisternae interpretable as GERL.The apical plasmalemma of isthmus cells uniquely exhibited abundant sulphated glycoconjugate and that of parietal cells revealed a less prominent, periodic neutral mucosubstance. Lateral and basal plasmalemmae varied from unstained to slightly reactive; basement membranes showed moderate reactivity with methods for visualizing complex carbohydrates. Abundance of glycogen further characterized surface epithelial cells of the corpus and of some parietal cells     

Histology and histochemistry of the parotid and the principal and accessory submandibular glands of the little brown bat

The parotid and the principal and accessory submandibular glands of the little brown bat. Myotis lucifugus (Vespertilionidae), were examined using light microscopy and staining methods for mucosubstances. The parotid gland is a compound tubuloacinar seromucous gland. Parotid gland secretory cells contain both neutral and nonsulfated acidic mucosubstances. The principal and accessory submandibular glands are compound tubuloacinar mucus-secreting glands. They contain somewhat atypical mucus-secreting demilunar cells that often appear to be interspersed between mucous tubule cells. The mucous tubule cells in both the principal and accessory submandibular glands contain sulfonmucins. Demilunar cells of the principal submandibular gland contain moderate amounts of nonsulfated acidic mucosubstances, but the corresponding cells of the accessory submandibular gland contain considerable neutral mucosubstance with very little acid mucosubstance. Intercalated ducts composed of cuboidal or low columnar epithelial cells are present in all three glands. Striated ducts in all glands are composed of columnar cells whose apices bulge into the ductal lumina. Excretory ducts are composed of simple columnar epithelium, with occasional basal cells that suggest a possible pseudostratified nature. The cells of the excretory ducts also have bulging apices. All duct types contain apical cytoplasmic secretory material that is a periodic acid-Schiff positive, neutral mucosubstance. Ductal apical secretory material is more evident in intercalated and striated ducts than in excretory ducts.     

The epidermis of Timarete filigera (Polychaeta, Cirratulidae): histochemical and ultrastructural analysis of the gland cells

The aim of this study was to verify whether different living conditions of Polychaeta are correlated with morphological and functional differences in the organization of the integument. For this purpose, we decided to study the epidermis of Timarete filigera, a non-tubicolous polychaete. With this objective in mind, we have identified the various cellular types responsible for mucous secretion in the epidermis of this species and defined the histochemical composition of the mucus produced by different types of gland cells. Three types of gland cells have been identified by histochemical and ultrastructural studies in the epidermis of this polychaete. The histochemistry was carried out using standard techniques and peroxidase-labelled lectins. In type 1 cells, the secretory granules contain neutral glycoproteins with glucosidic residues of GalNAc, Galbeta 1,3 GalNAc, glucosidic and/or mannosidic residues. In type 2 cells, the secretory granules contain acid glycoproteins mainly sulphated with glucosidic residues of GalNAc, Galbeta 1,3 GalNAc, glucosidic and/or mannosidic residues, and some terminal sialic acid. In type 3 cells, the residual granules have the same chemical composition as that of granules present in type 2 cells. The secretion of these glandular mucous cells consists of mainly sulphated acidic glycoproteins and GAG resistant to testis jaluronidase. In these cells, the residual granules have the same chemical composition as that of their secretion. The heterogeneity of mucus composition may be correlated with its different functions.     

Histochemistry of mucosubstances in the mantle of fresh water mussel, Parreysia corrugata var. nagpoorensis (Lea) II. Mucosubstances of the middle marginal fold.

The results of the various histochemical reactions on mucosubstances indicate that in the middle fold of the mantle edge two types of mucus cells exist, one producing sulphomucins and the other neutral mucosubstances. The cells secreting neutral mucosubstances are few in number. The sulphated mucus is strongly alcianophilic. The alcianophilia persists when the tissues are stained with alcian blue in concentration up to 0-5 M magnesium chloride. Testicular hyaluronidase has no effect on the staining pattern of the mucus.     

Morphological phenotypes and functional capabilities of submandibular parenchymal cells of the ferret investigated by protein, mucosubstance and enzyme histochemistry

Submandibular glands obtained post-mortem from mature ferrets of both sexes were examined with the use of light microscopical histochemical methods for proteins, mucosubstances and enzymes associated with cell functions or organelles. Demilunar cells showed carboxylated mucosubstances that were mainly non-sulphated, and diffuse activity for peroxidase, E600-sensitive esterase and acid phosphatase. Thiol groups were also detected in these cells. Central acinar cells showed sulphated mucosubstances, disulphides and reticular staining for thiamine pyrophosphatase. Intercalary ducts showed diffuse activity for NADH and NAD(P)H dehydrogenases. Striated ducts contained protein, tryptophan, disulphides, neutral mucosubstances and E600-sensitive esterase periluminally. Basally, the striated ductal cells showed variable activity for peroxidase, cytochrome oxidase, succinate dehydrogenase and acid phosphatase. Basolateral plasma membranes of these cells exhibited ouabain-sensitive Na,K-ATPase activity. The collecting ducts were characterized by variable periluminal staining for acid phosphatase, -glucuronidase, acid -galactosidase and E600-resistant esterase. The results suggest that the histological appearances of the acini of the submandibular gland of the ferret are dependent on the synthesis of secretory acid glycoproteins, that the striated ducts are involved with the secretion of tryptophan-rich product comprising neutral glycoproteins and showing esterase activity and with marked transport of ions and that the collecting ducts are involved with absorption.     

The cephalic glands of Brazilian reptilia and amphibia. IV. Histology of labial, premaxillary, and Duvernoy's glands in the colubrid snake Oxyrhopus trigeminus

A study of the morphology of the salivary glands of the colubrid snake Oxyrhopus trigeminus showed the following: The acini of supralabial, infralabial, and premaxillary glands are formed by mucous and mucoserous cells; the tubules of Duvernoy's gland are formed by seromucous cells; and mucous cells produce neutral and acid mucosubstances, mucoserous cells secrete neutral and acid mucosubstances and protein, and seromucous cells have neutral mucosubstance and protein secretions.     

Morphological characterisation of the digestive tract of the catfish Lophiosilurus alexandri Steindachner, 1876 (Siluriformes,Pseudopimelodidae)

The anatomical arrangement of the digestive tract and the length (cm) of the oesophagus and intestine of the catfish Lophiosilurus alexandri were described, and the intestinal coefficient was determined. L. alexandri oesophagus is short, in median position, and presents longitudinally folded mucosa, whilst its epithelium is stratified and non-keratinised, with mucous, claviform and epithelial cells. Stomach has “C” shape, with folded mucosa along cardiac region, disordered in the fundic region, and directed to the sphincter in the pyloric region. Its epithelium is simple prismatic, and cardiac and fundic portions have gastric glands. Cranial intestine is formed by pyloric flexure and descending loop attached to the right side of stomach. Middle intestine is winding and positioned to the right of caudal portion of stomach. Caudal intestine is linear and with a median position up to the anus. Intestinal coefficient was 1.39 ± 0.30 cm. Epithelium is simple prismatic with brush border and contains epithelial and goblet cells. Caudal region has highest concentration of goblet cells. Were detected neutral glycoproteins, carboxylated and sulphated acid glycoconjugates for mucous cells and goblet cells, and neutral glycoproteins for the apical region of gastric epithelial cells. Morphological features could be related to piscivorous species feeding habit.     

Structure and carbohydrate histochemistry of the esophagus in ten teleostean species

The histology and carbohydrate histochemistry of ten teleostean esophagi were compared. Structurally, the four layers of a typical vertebrate digestive tract were consistently present. The epithelium was always stratified and in all but one species (Ictalurus nebulosus) contained taste buds. Esophageal mucous cells were not the typical goblet cells seen in other vertebrates but appeared to be of six different types, pairs of which were associated with particular families. In esocids, poorly developed mucous acini and serous monogranular cells were present. In all species, the subepithelial connective tissue was not divided into definitive lamina propriae and submucosae due to the absence of muscularis mucosae. Variably present in this connective tissue region were argentophilic fibers and in esocids only, randomly dispersed striated muscle fibers. The arrangement of the muscularis was reverse to that of the general vertebrate plan. In mucous cells, three general types of epithelial mucosubstances were identified and in broad terms were recognized as sulfomucins, sialomucins and neutral mucosubstances. Morphological differences were accompanied by differences in carbohydrate localization, each esophageal epithelium containing at least two different mucosubstances. However, the mucosubstances identified in each mucous cell had a profile of characteristics different in some respects from any other. Thus teleostean esophagi appear to perform an integrated diversity of functions as reflected by their complex morphology and carbohydrate histochemistry.     

Ontogenetic development and composition of the mucous cells and the occurrence of saccular cells in the epidermis of Atlantic halibut

An increase in the number of mucous cells of the epidermis, as well as qualitative changes of the mucus composition from predominantly neutral to a mixture of neutral and sulphated glycoproteins occurred during the development from a pelagic larva to a bottom-dwelling flatfish. Numerous saccular cells were observed in the epidermis of the yolk-sac larvae that disappeared simultaneously as the mucous cells increased in number in the epidermis of the metamorphosed halibut. These findings may help to understand the protective role of the mucus layer of Atlantic halibut during development as compared to other fish species in aquaculture.     

Observations on the structure and histochemistry of the skin of Mystus gulio (Ham.) (Osteichthyes: Siluriformes, Bagridae)

The skin of Mystus gulio (Ham.) is typical of siluroids in not having any scales. Large number of mucous cells and sacciform granular cells, interspersed with taste buds, were found in the epidermis. Histochemical tests showed the presence of weakly sulphated mucopolysaccharides in the mucous cells, while the sacciform granular club cells were found to be proteinaceous, with a small amount of lipids and phospholipids. The dermis is composed of a stratum laxum and a stratum compactum. The subcutis was found to consist of loosely arranged collagen fibres and fat cells.     

Studies on the alimentary canal of amphipods: histochemistry of cephalic mucous glands in Talorchestia martensii (Weber) (Crustacea: Amphipoda)

With a view to analyse the chemical nature and the probable functional significance of the cephalic mucous glands the mucosubstances secreted and elaborated by these glands were investigated. All recent and standard histochemical techniques were employed. These reactions revealed that the three groups of glands namely the oesophageal, lateral and maxillipede groups are charged with the task of secreting both acid and neutral mucopolysaccharides. Of these three, maxillipede groups are elaborating most of the neutral mucopolysaccharides and the other two groups are mainly involved in elaborating acid mucosubstances and to a little extent neutral mucosubstances. The acidic nature of the mucosubstances is partly due to hyaluronic acid and partly due to sialic acid. This was confirmed by hyaluronidase and neuraminidase treatment (digestion tests). The glands are also involved in secreting glycoproteins which was evidenced by their positivity to alcian blue/naphthol yellow and Congo red reactions. Entanglement of food and provision of fluid vehicle for lubrication as well as to achieve the desired consistency for digestion may be given as chief functions.     

Histochemical observations of the haemocytes of Locusta migratoria.

Five of the six categories of haemocytes of Locusta migratoria, that is, the plasmatocytes, spherule cells, granulocytes, coagulocytes and oenocytoids, contain conspicuous granules of mucosubstance in their cytoplasm. The mucosubstance has been characterized by using a series of histochemical tests, including Alcian Blue staining at different pH levels and salt concentrations, the periodic acid-Schiff (PAS) test, the high iron diamine test, enzymatic digestions and sequential staining methods. The results indicate that four different mucosubstances occur in a granular form, although not all four are found in every blood cell type. The mucosubstances are a neutral glycoprotein and neuraminidase-resistant, sulphated and non-sulphated sialomucins. The non-sulphated sialomucin occurs in both periodate-reactive and -unreactive forms.     

Glyconjugates in epidermal, branchial and digestive mucous cells and gastric glands of gilthead sea bream, Sparus aurata, Senegal sole, Solea senegalensis and Siberian sturgeon, Acipenser baeri development.

Epidermal, branchial and digestive mucous cells, and the gastric glands of larvae/postlarvae (from hatching until 45 days posthatching) of three fish species (two teleostean and a chondrostean) were investigated using conventional histochemical methods (periodic acid schiff -PAS-, diastase-PAS; alcian blue pH 0.5, 1 and 2.5) in order to distinguish neutral and acidic (carboxylated and sulphated) glycoconjugates, as well as bromophenol blue reaction for identification of proteins. Additionally, the presence and distribution of sugar residues in the oligosaccharide side chains of glycoconjugates were investigated using horseradish peroxidase (HPR)-conjugated lectins (Con A, DBA, WGA and UEA-I). Most mucous cells (digestive, epidermal and branchial) of Siberian sturgeon, Acipenser baeri, sea bream, Sparus aurata and Senegal sole, Solea senegalensis larvae were PAS- and alcian blue- (pH 2.5 and 0.5) positive, with small variations between organs/tissues and species. Bromophenol blue reaction (general proteins) was positive in a minority of the mucous cells, usually in those cells which were PAS-negative. Proteins rich in sulphydryl (-SH) and/or disulphide (-S-S-) groups related with the glycoprotein nature of the glycoconjugates present in mucous cells were also observed. Epidermal, branchial and digestive mucous cells of all studied larvae did not contain glycogen or lipids. Con A lectin staining was negative in all mucous cells types of sea bream and sole, but oesophageal mucous cell of sturgeon were reactive to different lectin reactions, suggesting the presence of mannose -Man- and/or glucose -Glc-, L-fucose -Fuc- ; N-acetyl-D-galactosamine -GalNAc-, as well as N-acetyl-D-glucosamine- GlcNAc - and/or sialic acid -NANA- residues. Digestive mucous cells of all studied larvae were positive to WGA and DBA lectins. Epidermal and branchial mucous cells of sea bream and sole were Con A, DBA and UEA-I unreactive. However, mucous cells of sturgeon larvae were stained with UEA-I lectin. Gastric glands appear very early in sturgeon stomach larvae development (between 5-6 days posthatching) but rather late (around 40 days) during the ontogeny of sole and sea bream larvae. These glands contain neutral glycoproteins with Man and/or Glc, Fuc, GlcNAc- and/or sialic acid and rich in GalNAc- sugar residues, as well as proteins moderately rich in arginine, and others particularly rich in tyrosine and tryptophan.