Ultrastructure and histochemical study of glycoconjugates in the gills of the white croaker (Micropogonias furnieri)

The ultrastructure of the primary and secondary lamellae of gills was investigated in a marine teleost, the white croaker. The following cells were identified and briefly described: pavement cells, mucous cells, mitochondria-rich cells and rodlet cells. These cell types are present throughout the length of the lamellae. They are studied by means of a series of carbohydrate histochemical methods, including lectin procedures. Neutral sugars and substituted sialic acid were detected by means of periodic acid-borohydride reduction-saponification-periodic acid Schiff reaction (PA/Bh/KOH/PAS), saponification-selective periodic acid Schiff reaction (KOH/PA*S) and saponification-selective periodic acid-borohydride reduction-periodic acid Schiff reaction (KOH/PA*/Bh/PAS) histochemical techniques. A battery of seven lectins was used to study binding on tissue sections at the light microscopic level to characterize glycoconjugates in gills. The reaction to Canavalia ensiformis agglutinin (Con-A), Triticum vulgaris agglutinin (WGA), and Ricinus cummunis agglutinin-1 (RCA-1) was weak in pavement cells; unlike Con-A, the reaction to WGA and RCA-1 was more intense in mucous cells. Arachis hypogaea agglutinin (PNA) lectin showed a strong reaction in mucous cells. Ulex europaens agglutinin-1 (UEA-1) lectin was negative in all cell types. The lectin pattern was similar for both primary and secondary lamellae, except for PNA reaction, which was weak in the pavement cells of the secondary lamella and negative in the pavement cells of the primary lamella.     

Histological and histochemical characterization of the mucosa of the digestive tract in flower fish (Pseudophoxinus antalyae)

The wall of the digestive tract is composed of the tunica mucosa, tunica muscularis and tunica serosa. Lamina-submucosa separation or any glands were not observed in tunica mucosa. Goblet cells were determined to constitute a much larger reserve at digestive tract mucosa. Histochemical analysis of the intestine of flower fish (Pseudophoxinus antalyae) showed that gastrointestinal mucous content included sulphate-esters and/or carboxylic [Alcian blue (AB) 0.06+], glycogene and/or oxidable dioles [periodic acid/Schiff+ (PAS+)], neutral or acid-rich (PAS/AB pH 2.5+), sialic acid residues (KOH/PAS) and strong acid sulphated [Aldehyde fuchsin+ (AF+)] glycoproteins (GPs). Except these mucosubstances to lower densities, densely sulphate (AB pH 2.5+), O-sulphate esters (AB pH 1+) strong and weak sulphated (AB 0.3 M+), GPs were also determined.     

Morphological and histochemical characterization of the mucosa of the digestive tract in Engraulis anchoita

The histomorphological aspects as well as the histochemical content and distribution of glycoproteins (GPs) in the mucosa of the digestive tract of the anchovy Engraulis anchoita were studied. The buccopharyngeal cavity is lined by a squamous stratified epithelium with mucous superficial cells; the oesophagus shows two zones, cranial with a squamous stratified epithelium with mucous superficial cells and caudal with a columnar secretory epithelium. Finally, the stomach presents both the cranial and pyloric portion lined with a simple columnar epithelium. Tubular branched glands, formed by a single type of glandular cell, located along the stomach, are more numerous in the cranial portion. The GPs were identified with (1) oxidizable vicinal diols; (2) sialic acids and some of their chain variants, C7 or C9; (3) sialic acid residues with O-acyl substitution at C7 or C8; (4) carboxyl groups and (5) sulphate groups. Histochemical tests showed that the buccopharyngeal cavity presented the largest amount of the different types of mucosubstances. Epithelial secretory cells were found in the oesophagus, which synthesized a large quantity of sialosulphoglycoproteins likely to be related to a protective role. The surface epithelium of the stomach synthesizes and secretes acid and neutral GPs, probably related to the movement of fluids and to the absorption of easily digested substrates, respectively. Although great differences exist between different species, in E. anchoita as in other fish species, the wall of the digestive tract is composed of the four layers classically described for vertebrates. The GPs secreted by the epithelial cells are suggested to be important for the protection and inhibition of microorganisms. In addition, they are involved in enzymatic digestion of food, absorptive functions and lubrication of the alimentary tract.     

Glycoproteins in the epithelium of lips and associated structures of a hill stream fish Garra lamta (Cyprinidae, Cypriniformes): a histochemical investigation

A series of histochemical procedures were employed to localize and characterize glycoprotein (GP) classes elaborated in the epithelia of the upper and lower lips and associated structures, namely the rostral cap, the adhesive pad, the horny upper and lower jaw sheaths and the folds of skin between them, of a hill stream fish Garra lamta. The epithelia of the lips, the folds of skin and the major portions of the rostral cap and the adhesive pad are mucogenic. The epithelia of the horny jaw sheaths and parts of the rostral cap and the adhesive pad are keratinized. Based on the histochemical characterization of GPs, the cells involved in the secretions in the epithelia at the mucogenic regions of the rostral cap and the adhesive pad comprise the epithelial cells, the type A mucous cells and the club cells. In the lips and the folds of skin, in contrast, the club cells are absent and most mucous cells belong to the type B category. Type A mucous cells are few. GPs elaborated by cellular components of the mucogenic epithelia include GPs with oxidizable vicinal diols, GPs with O-sulphate esters, GPs with sialic acid residues without O-acyl substitution or with O-acyl substitution at C7, C8 or C9 and GPs with O-acyl sugars. The different types of cells show significant differences in the classes as well as in the concentrations of the GPs elaborated by them. GPs have also been identified in the subcorneal space between the unculi and the epithelial cells in the replacement layer in the epithelia at the keratinized regions. Elaboration of more than one type of GPs suggests a basis for functional discrimination in their role in the mucous secretions at the surface as an adaptation to the feeding ecology and the environment inhabited by the fish.     

Mucous Cells in Micropogonias furnieri gills: Histochemistry and Ultrastructure

The characteristics of the mucous cells located in the gills of the fish Micropogonias furnieri were investigated. Using histochemical procedures that included methods for localization and characterization of glycoproteins (GPs), no differences were detected between the mucous cell contents of the primary and secondary lamellae. The GPs were identified with (a) oxidizable vecinal diols; (b) sialic acids and some of their chain variants, C7 or C9; (c) carboxyl groups and (d) sulphate groups. The electron microscope showed large mucous globules of different electro densities from mucous cells located deep in the epithelium between the other epithelial cells; the release of mucus by exocytosis was observed. GPs secreted on the surface of the mucous cells was suggested to be important for the lubrication, protection and inhibition of microorganisms. It is possibility that GPs could have similar roles in Micropogonias furnieri gills.     

Glycoproteins in the Buccal Epithelium of a Carp,Cirrhinus mrigala (Pisces,Cyprinidae): A Histochemical Profile

Glycoproteins (GPs) were visualized histochemically in the secretory cells – the mucous goblet cells (the type A and the type B), the rodlet cells and the epithelial cells in different regions of the buccal cavity of Cirrhinus mrigala. The type A mucous goblet cells, the type B mucous goblet cells, the rodlet cells and the epithelial cells elaborate GPs with oxidizable vicinal diols and GPs with sialic acid residue without O‐acyl substitution. The type A mucous goblet cells, in addition, contain moderate amounts of GPs with O‐sulphate esters. The type B mucous goblet cells, in contrast, contain high concentrations of GPs with O‐sulphate esters. The rodlet cells secrete small amounts of GPs with oxidizable vicinal diols. The analysis of the results elucidates interesting differences in the composition and concentration of GPs in the mucus elaborated by the secretory cells indicating the potential importance of the glycoproteins in the buccal cavity. These GPs could be considered to represent a mechanism for modulation of the composition of the protective mucus layer correlated to specific functions.     

The mucosa of the digestive tract in Micropogonias furnieri: a light and electron microscope approach

The histomorphological aspects as well as the histochemical content and distribution of glycoproteins (GPs) in the mucosa of the digestive tract of the white croaker Micropogonias furnieri were studied. The buccopharyngeal cavity and the esophagous showed a squamous stratified epithelium with mucous cells. The stomach presented three portions: cardias, fundus and pylorus. Tubular glands formed by a single type of gland cell were located along the cardias and fundus. Histochemical tests showed that the buccopharyngeal cavity and the esophagous presented the largest amount of the different types of mucosubstances. Both organs showed abundant secretory mucous cells that synthesize large quantities of neutral, sulphated and sialylated GPs. The surface epithelium in the cardias and fundus synthesized and secreted scarce sialylated and neutral GPs whereas the secretions of the apical surface were abundant. The pylorus secreted large amounts of neutral as well as sulphated and sialylated GPs. Gland cells secreted neutral GPs. The ultrastructural features of the gut cells were quite similar to those of other teleosts. The buccopharyngeal cavity and the esophagous surface epithelial cells, identified by their superficial localization, were characterized by cytoplasmic vesicles of different size. Abundant goblet cells with secretory mucous granules were also present. Gastric glands in the stomach contained just one form of cell with a fine structure similar to cells that secrete pepsinogen.     

泰山螭霖鱼肠道的显微和超微结构

采用光镜和扫描电镜技术 ,对泰山螭霖鱼 (Varicorhinusmacrolepis)的肠道进行了观察。结果表明 :泰山螭霖鱼无胃 ,食管之后是肠道 ,起始端膨大呈球状。肠道由前肠、中肠和后肠组成 ,肠管直径由前肠到后肠逐渐变小。各段肠壁均分为粘膜、肌层和浆膜 3层。粘膜上皮由柱状细胞和杯状细胞组成 ,肌层分内环行和外纵行 2层。粘膜向肠腔内突出形成许多粘膜褶 ,有的呈指状、杵状 ,有的有分支。由前肠到后肠 ,粘膜褶由高变低 ,数量逐渐减少 ;杯状细胞数目由多变少 ;肌层逐渐变薄。扫描电镜下 ,肠道的粘膜褶大体上呈纵向锯齿状 ,并且粘膜褶上还有次级皱褶。柱状上皮细胞表面多呈圆形 ,前肠、中肠柱状上皮细胞轮廓和界限清楚 ,常呈隆起状 ,而后肠上皮细胞表面较平坦。前肠柱状上皮细胞游离面的微绒毛长而密 ,后肠的短而稀疏。前肠的杯状细胞常常有较大的分泌孔 ,周围有分泌物 ,粘膜表面有粗大的分泌颗粒 ;后肠杯状细胞的分泌孔较小 ,粘膜表面有较多细小分泌颗粒。     

Histomorphology of the stomach, proventriculus and ventriculus of the red jungle fowl

The cranial chamber (proventriculus) and caudal chamber (ventriculus) of the stomach of the Red jungle fowl (Gallus gallus spadiceus) were examined by means of light microscopy. Both chambers presented folds of the tunica mucosa lined by a simple prismatic epithelium that was positive for neutral mucin. Simple tubular glands occupied the lamina propria of both chambers; in the ventriculus of older birds, they showed a coiled base. These ventricular glands were lined by simple cuboidal cells represented by the chief cells and a few large basal cells. The luminal and tubular koilin rodlets and folds of the ventriculus were positive to periodic acid Schiff (PAS) stain. The proventricular glands were situated between the inner and outer layers of the lamina muscularis mucosae. Cells lining the tubulo-alveolar units of the proventricular glands showed a dentate appearance. Vacuoles were not observed, and the cells were negative for Alcian-PAS stain. The tunica submucosa was very thin in the proventricular wall. In the ventriculus, it was not separated from the lamina propria owing to the absence of any lamina muscularis mucosae. The tunica muscularis of the proventriculus was formed by a thick inner layer of circular smooth muscle fibres and a thin outer layer of longitudinal fibres. In addition to these layers, oblique muscle fibres formed the most internal layer of the tunica muscularis in the ventriculus.     

Morphological study of the oesophagus and stomach of the Gopher snake Pituophis catenifer

The gastrointestinal tract of the snake has various distinctions from mammals, birds and other reptiles. Five gopher snakes (Pituophis catenifer) were studied in relation to the gross anatomical measurements of visceral organs relative to body length as well as the histology of the oesophagus and the stomach. The oesophagus closely resembles the empty stomach upon gross examination. A small palpable thickening was observed at the junction of the oesophagus with the stomach. In both the oesophagus and the stomach, there were cellular and structural differences observed in the tunica mucosa which can be linked to the feeding habits and natural biology of the snake when compared to those of mammals. Both oesophagus and stomach were lined by simple columnar to pseudostratified columnar epithelium. There were no glands in the wall of the oesophagus. Scattered ciliated triangular cells (brush cells) were present among the columnar epithelial cells in the distal portion of the oesophagus. The stomach can be divided into three portions (proximal, middle and distal). The stomach has a small non-glandular portion with low folds. After this small non-glandular portion, glands started to appear and gradually increase in quantity. The largest quantity of glands appeared in the middle portion of the stomach with more branching folds resulting in a decrease in the lumen diameter. The tunica muscularis increased in thickness at the oesophageal and the pyloric-duodenal junctions. Positive statistical correlations were established in thickness of the tunica muscularis between proximal and distal portions of the oesophagus and the stomach.     

Characterization of the complex carbohydrates in the zona pellucida of mammalian oocytes using lectin histochemistry

The objective of this study was to characterize the glycoconjugates present in the zona pellucida of the follicular oocytes in sheep, goats and pigs. The zona pellucida was stained with periodic acid-Schiff, low iron diamine, high iron diamine, and nine different lectin horseradish conjugates: Con-A, SBA, DBA, PNA, RCA-I, GSA-II, WGA, LTA and UEA-I. Staining with DBA, PNA, SBA and RCA-I was performed with and without saponification with KOH and sialidase digestion. The results showed the presence of neutral and acidic glycoconjugates with different terminal sugars and also sialic acid radicals in the zona pellucida of all the animals studied. In particular, the positive staining with WGA, SBA, PNA and RCA-I suggests the presence of oligosaccharides with N-acetyl-d-glucosamine and sialic acid linked to the penultimate -N-acetyl-d-galactosamine and to the disaccharide galactosyl-(1-3)-N-acetyl-d-galactosamine. The terminal trisaccharide sialic acid galactosyl-(1-4)-N-acetyl-d-glucosamine was identified only in the zona pellucida of ovine and procine oocytes. Thus, the zona pellucida exhibited species-specific variations in the content and distribution of lectin-binding patterns that may reflect the species specificity of gamete interaction.Abbreviations HID high iron diamine - HRP horseradish peroxidase - LID low iron diamine - PAS periodic acid-Schiff - PBS phosphate-buffered saline; see also Tables I and II     

Rodent renal structure differs among species

In the present study, we histologically and morphometrically investigated species differences in renal structure using laboratory rodents (mice, gerbils, hamsters, rats, and guinea pigs). Morphometric parameters were as follows, 1) diameter of the cortical renal corpuscles, 2) diameter of the juxtamedullary renal corpuscles, 3) percentage of the renal corpuscles with a cuboidal parietal layer, 4) number of nuclei in proximal convoluted tubules (PCTs) per unit area of cortex, 5) semi-quantitative score of the periodic acid-Schiff (PAS) -positive granules in PCTs, and 6) semi-quantitative score of the PAS-positive granules in proximal straight tubules (PSTs). Significant species differences were detected for each parameter, and particularly severe differences were observed in the PAS-positive granules of PCTs and PSTs. Granular scores varied among species and sexes. Vacuolar structures that did not stain with PAS or hematoxylin-eosin were observed in the renal proximal tubules. The appearance and localization of these vacuolar structures differed remarkably between species and sexes.     

Histomorphometric and histochemical characteristics of the oesophagus of the greater mouse-eared Bat,Myotis myotis (Borkhausen, 1797)

The aim of this study was to examine the histomorphometric and histochemical structure of oesophagus of the wild-caught greater mouse-eared bat M. myotis. For this purpose, 10 specimens of oesophagus were collected and processed. The oesophagus wall of M. myotis is composed of four layers: tunica mucosa, tunica submucosa, tunica muscularis and tunica adventitia. The mucosa is covered by a non-keratinized stratified squamous epithelium. There were no glands in the wall of the oesophagus. Tunica muscularis is composed of two muscle layers: internal circular muscular layer and an external longitudinal muscular layer. Histochemical studies revealed that the oesophagus was AB/PAS and PAS positive indicating the presence of acidic and neutral mucosubstances. AB-PAS staining shows that glycoproteins were predominant in the all examined layers of the oesophagus. Because of the absence of oesophageal glands in M. myotis, positive reaction with AB-PAS staining may be due to secretion of salivary glands. Absence of oesophageal glands reflects the functional adaptation as high food passage rate for the insectivorous feeding habits of animals.     

Microscopic anatomy of the oesophagus in the southern white-breasted hedgehog (Erinaceus concolor) a histochemical,stereological, and scanning electron microscope study

The present work was designed to investigate the microscopic structure of the oesophagus in the southern white-breasted hedgehog (Erinaceus concolor) using histochemical staining, Scanning electron microscope (SEM), and stereological procedures. Four adult males were included in our study. Serial sections of the entire length of the oesophagus were stained with aldehyde fuchsin, alcian blue (pH 2.5), Periodic acid Schiff (PAS), and Masson's trichrome. Then, the total volume of the oesophagus, and the total volume of its different layers, were estimated using Cavalieri's principle. The oesophageal epithelium was a non-keratinized stratified squamous type. Muscularis mucosa was present as a thick layer between lamina propria and submucosa and its thickness was increased toward the stomach. Tunica submucosa was a loose connective tissue containing an oesophageal gland with PAS-positive and AB-positive reactions throughout the submucosa and become denser toward the stomach. The tunica muscularis consisted of two distinct striated muscle layers, and its thickness was decreased toward the stomach. On SEM images, the cervical and thoracic oesophagus showed shallow folding, while the abdominal part had deeper folds. The present findings indicate that the histological properties of the oesophagus in southern white-breasted hedgehogs have slight similarities with rodents and considering its epithelium, submucosal glands and tunica muscularis more resemble with dog oesophagus. The obtained results may be quite helpful to improve the current knowledge of the histophysiology of the hedgehog gastrointestinal tract as a member of eulipotyplan mammals and as a pet for biologists and veterinarians.     

Complex Carbohydrates Occurring in the Digestive Apparatus of Umbrina Cirrosa (L.) Fry

The glycosoaminoglycans in the digestive apparatus of immature fish have important biological functions and are involved in morphofunctional differentiation. The aim of this study was to investigate the glycoconjugate histochemistry in the different parts of the digestive apparatus (oesophagus, stomach, intestine) of Umbrina cirrosa (L.) fry using classical histochemical reactions (periodic acid-Schiff, Alcian blue pH 2.5, Alcian blue/periodic acid-Schiff, high iron diamine, low iron diamine) in conjunction with glycolytic digestions that degrade different classes of glycosoaminoglycans. No differences were observed in the reactivity to conventional histochemical staining of the oesophagus, stomach or intestine among 27-, 34- or 44-day-old fry. In the oesophagus, the mucopolysaccharides contained chondroitin sulphates B and A and/or C, heparan sulphate and chondroitin. In the stomach, only neutral glycoconjugates were revealed, whereas in the intestine there were only chondroitin sulphates. Some differences in the type and content of glycoconjugates were found in Umbrina cirrosa (L.) fry compared to those of adult subjects, probably related to different dietary habits and to changes in the environmental conditions.     

Mucus cells in the digestive tract in prenatal platyfish larvae (Poeciliidae, Teleostei)

The appearance and histochemical properties of mucus cells in various parts of digestive tract in prenatal larvae of platyfish (Xiphophorus maculatus), a stomachless teleost, are described and compared. Such cells occurred regularly throughout the entire epithelial cell layer in mouth, pharynx, oesophagus and intestine in 6 mm long larvae i.e. approximately 1 week before delivery, but were very scarce in 4 mm long larvae. The mucin in these cells was strongly stained by alcian blue at pH 2.5 and weakly coloured by this dye at pH 1.0. It displayed a clean blue colour after high iron diamine followed by alcian blue (pH 2.5), except in some very few cells which displayed a purple-brown colour after this treatment. The mucus cells displayed various colours between purple-blue and magenta when the alcian blue (pH 2.5) was followed by periodic acid-Schiff (PAS) solution; the magenta-coloured cells were mainly confined to oesophagus. Together these findings suggest that the mucin in the digestive tract of prenatal platyfish consists mainly of non-sulphated, carboxylated glycoconjugates. The observations from the present lectin histochemistry suggest that the amount of galactosamine and glucosamine in this mucin varies much from cell to cell. Also, the various colours after PAS suggest a significant cellular heterogeneity in the mucus cell population. This may reflect different stages in development and maturation or a true and permanent cellular heterogeneity, suggesting that this mucus is able to play a number of important roles even a week before the larvae start to feed and digest.     

Viral Plasmacytosis (Aleutian Disease) in Mink: IV. Cytoplasmic Glycoprotein Inclusions and Their Differentiation from the Viral Inclusions of Distemper

The periodic acid-Schiff (PAS) method was found to be a convenient stain for differentiating the specific intracytoplasmic inclusions of distemper from similar eosinophilic inclusions seen in plasmacytosis and occasionally in other disease conditions of mink. These latter inclusions stained strongly with PAS and appeared to be composed of glycoprotein. Although their significance is not known, it is probable that they represent abnormal globulins produced in great excess by the proliferating plasma cells. A pathogenetic hypothesis is offered.     

Canine granular cell tumour (myoblastoma): a report of four cases and review of the literature

Four cases of canine granular cell tumour (myoblastoma) were diagnosed at the Washington Animal Disease Diagnostic Laboratory between 1977 and 1981. Two of the tumours occurred in the tongue, one in the lip and one in the larynx. Three cell types were found in the tumours. Granular cells, with abundant periodic acid-Schiff (PAS)-positive cytoplasmic granules, were most numerous. Interstitial cells resembled fibroblasts and were often adjacent to collagen fibrils. Angulate body cells contained PAS-positive, ovoid cytoplasmic inclusions composed of microtubular subunits. Review of these and reported cases indicates no breed or sex predisposition for this rare tumour. The tongue is the most common site and all but one tumour have occurred in or adjacent to the oral cavity. There have been no reports of recurrence or metastasis of granular cell tumours except the recurrence of a disputed case in the subcutis of a dog.     

Gill epithelium of an angler catfish,Chaca chaca (Siluriformes,Chacidae): Enzyme and glycoprotein histochemistry

A series of histochemical techniques have been employed to localize alkaline phosphatase, acid phosphatase, non-specific esterase, catalase and peroxidase; and to visualize and characterize glycoprotein (GPs) moieties in the epithelium of gill arch, gill filaments and secondary lamellae of an angler catfish Chaca chaca. The epithelium of gill arch and gill filament shows strong alkaline phosphatase activity in the deeper layer epithelial cells; strong non-specific esterase activities in the outer layer epithelial cells; and weak acid phosphatase activity throughout the epithelium. The activity of these enzymes in the secondary lamellae is weak. The catalase and peroxidase show strong activities in the blood cells of the secondary lamellae. Various classes of GPs have been identified and characterized in the mucous secretions of the gill epithelium of C. chaca. These include—GPs with oxidizable vicinal diols, GPs with sialic acid residues without O-acyl substitution and GPs with O-sulphate esters. The functional significance of different enzymes in gill epithelium and the GPs in the mucus secreted on the surface has been discussed with the physiology of the gills in relation to the characteristic habit and habitat of the fish.     

Histochemistry of sialoglycoconjugates in goat submandibular glands

The functional properties of sialic acids appear to be manifold. Therefore, they are considered as essential components of saliva. In this study, the localization of sialoglycoconjugates in the submandibular glands of Japanese miniature (Shiba) goat was examined by light and electron microscopic histochemical methods. The submandibular glands exhibited a large amount of sialic acids. Additionally, sialic acids with O-acetyl substitutions were detectable in the mucous acinar cells and serous demilunar cells. According to lectin histochemical methods, the mucous and serous cells mainly contained the Siaα2-6Gal/GalNAc sequence. These sialoglycoconjugates generated by the submandibular glands may specifically participate in the maintenance of the viscoelastic properties of saliva, protection of oral tissues and prevention of pathogenic microbial attacks. Therefore, our results suggest that they are essential components of saliva to maintain oral health.