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1.
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.  相似文献   

2.
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.  相似文献   

3.
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.  相似文献   

4.
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.  相似文献   

5.
A histochemical study using conventional carbohydrate histochemistry (periodic‐acid staining including diastase controls, alcian blue staining at pH 1 and 2.5) as well as using a battery of 14 fluorescein isothiocyanate (FITC)‐labelled lectins to identify glycoconjugates present in 10 different areas of the skin of a catfish (Arius tenuispinis) was carried out. The lectins used were: mannose‐binding lectins (Con A, LCA and PSA), galactose‐binding lectins (PNA, RCA), N‐acetylgalactosamine‐binding lectins (DBA, SBA, SJA and GSL I), N‐acetylglucosamine‐binding lectins (WGA and WGAs), fucose‐binding lectins (UEA) and lectins which bind to complex carbohydrate configurations (PHA E, PHA L). Conventional glycoconjugate staining (PAS staining, alcian blue at pH 1 and 2.5) showed that the mucous goblet cells contain a considerable amount of glycoconjugates in all locations of the skin, whereas the other unicellular gland type, the club cells, lacked these glycoconjugates. The glycoproteins found in goblet cells are neutral and therefore stain magenta when subjected to PAS staining. Alcian blue staining indicating acid glycoproteins was distinctly positive at pH 1, but gave only a comparable staining at pH 2.5. The mucus of the goblet cells therefore also contains acid glycoproteins rich in sulphate groups. Using FITC‐labelled lectins, the carbohydrate composition of the glycoproteins of goblet cells could be more fully characterized. A distinct staining of the mucus of goblet cells was found with the mannose‐binding lectins LCA and PSA; the galactosamine‐binding lectins DBA, SBA and GLS I; the glucosamine‐binding lectin WGA; and PHA E which stains glycoproteins with complex carbohydrate configurations. No reaction occurred with the fucose‐binding lectin UEA and the sialic acid‐specific lectin SNA. In addition, the galactose‐binding lectins PNA and RCA showed only a weak or completely negative staining of the mucus in the goblet cells. The specificity of the lectin staining could be proved by inhibiting binding of the lectins by competitive inhibition with the corresponding sugars. From these data, we can conclude that the mucus produced by the epidermal goblet cells of A. tenuispinis is rich in mannose, N‐acetylgalactosamine and N‐acetylglucosamine residues.  相似文献   

6.
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.  相似文献   

7.
1. Morphological and histochemical observations were done on the chicken anterior and posterior lingual glands. Histology, ultrastructure and glycoconjugate histochemistry were investigated by means of light and electron microscopy using staining specific for complex carbohydrates. 2. In the anterior lingual glands there are lateral and medial zones showing different morphological and tinctorial features. The secretory cells are typical mucous cells. 3. Histochemical reactions revealed the presence of acidic glycoconjugates with terminal sialic acid residues, and glycoconjugates vicinal diol and sulphate groupings in the secretory granules. 4. It is suggested that the main functions of lingual glands are the lubrication of boli and protection from micro-organisms.  相似文献   

8.
The histology of the pharyngeal cavity and oesophagus of the freshwater 'silverside'Odontesthes bonariensis (Cuvier and Valenciennes) and the characteristics of their mucous cells were investigated. The histological characterization of its digestive wall revealed that the mucosa is thrown with longitudinal folds. The epithelium covering the folds was stratified with abundant mucous cells and gustative corpuscles, which are lacking in the oesophagus. The muscularis mucosa was absent. The submucosa presented the compactum stratum. The muscularis was organized in longitudinal and circular layers of muscular striated fibres. The serosa with a flat epithelium was located only in the oesophagus. Using histochemical procedures including methods for localization and characterization of glycoproteins (GPs), no differences were detected between the mucous cells contents of the pharyngeal cavity and those of the oesophagus. The mucous cells showed a weak periodic acid-Schiff (PAS) positive reaction in their content. The reactions for the differential analysis of sialic acids from GPs are feeble for periodic acid-Schiff at low temperature and low pH (PA*S) and KOH/PA*S and strong for periodic acid/borohydride/KOH/PAS (PA/Bh/KOH/PAS) and KOH/PA*/Bh/PAS revealing the scarce presence of C7 or C9 substituted and non-substituted sialic acids and the abundance of C7, C8 substituted sialic acids, O-acyl sugars and neutral sugars respectively. The results suggest that the pharyngeal cavity with the gustative corpuscles would induce the gastric secretion whereas the oesophagus is mainly involved in the transport of the food bolus to the stomach with the aid of abundant secretion of mucus. GPs secreted on the surface of the mucous cells, likely related to environmental conditions, would be involved in the lubrication, protection against abrasion and inhibition of microorganism proliferation.  相似文献   

9.
Histochemical properties of goblet cells in intestine of a stomach‐less teleost, tiger barb (Puntius tetrazona), and a stomach‐containing teleost, black tetra (Gymnocorymbus ternetzi), are described and compared. The intestine goblet cells were mostly wide in both species, but in tiger barb, some of them were markedly thinner. In black tetra, all the intestine goblet cells displayed magenta colour after PAS, whereas in the tiger barb, only the thinner goblet cells displayed such affinity. The latter cell type was coloured strongly magenta when the tissue was treated with alcian blue (pH 2.5) followed by PAS, whereas the wide goblet cells in tiger barb and all goblet cells in black tetra displayed mainly a blue colour after such treatment. Further, the goblet cells in both species were coloured cleanly blue after high iron diamine followed by alcian blue (pH 2.5). The intestine goblet cells in both species displayed a moderate affinity to WGA and concanavalin A lectins and no affinity to DBA. Most of the goblet cells displayed no affinity to PNA, but some of them in the tiger barb displayed a moderate or strong affinity to this lectin. The affinity to WGA was somewhat strengthened after pre‐treatment with neuraminidase. These results suggest that tiger barb contains two types or variants of intestinal goblet cells: high numbers of wide cells filled by acidic, non‐sulphated mucin and some thinner cells filled by neutral mucin. The intestine goblet cells in black tetra were filled by variable amounts of neutral and acidic mucin, but the total number of such cells is much less than in tiger barb. The present lectin and neuraminidase results suggest that the intestinal mucins in both species contain significant amounts of N‐acetylglucosamine, sialic acid and glucose/mannose, but seem to lack N‐acetylgalactosamine. However, some of these cells in tiger barb contain moderate to large amounts of galactose. Together, these results suggest significant species‐specific features of the intestine goblet cells and mucin types in tiger barb and black tetra. In conclusion, the present results suggest that the diet and feeding habits in stomach‐less teleosts compared with stomach‐containing teleosts, greatly influence the number of intestine goblet cells and type of mucin in these cells.  相似文献   

10.
泰山螭霖鱼肠道的显微和超微结构   总被引：2，自引：0，他引：2  
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。  相似文献   

11.
The state of mucus synthesis in the goblet cells of the small intestine was studied in conventional piglets infected with a dose of 200,000 oocytes of the coccidium Isospora suis the first and fifth day after parturition. The synthesis of mucus and its chemical characteristics undergo significant changes during the third and fourth day after infection. The activity of acid and neutral mucous substances declines; their level and the physiological synthetic function of goblet cells begin to return to the normal during the period starting on the eight to tenth day after infection. However, there were no fully functioning goblet cells in the broken numerical ratio even at the end of the period of investigation, i.e. the 13th day after infection. The thin surface layer of mucus remained almost unchanged within the whole extent of the small intestine parts studied.  相似文献   

12.
The structure and histochemical properties of the intestine in bronze corydoras (Corydoras aeneus), a stomach‐containing teleost, are described, with emphasis on goblet cells and mucin types. The proximal intestine displayed a normal structure for teleosts, whereas the distal intestine was wide, translucent, thin‐walled, richly vascularized and constantly filled with air, suggesting an important respiratory role. Goblet cells were common throughout the entire intestine and displayed a variable, but mainly faint metachromatic colour after toluidine blue. They were moderately coloured by alcian blue at both pH 2.5 and 0.2 and displayed no colour after periodic acid followed by Schiff's solution (PAS), but a distinct purple‐brown colour after high iron diamine followed by alcian blue (pH 2.5). Together, these results suggest that the mucin in the intestine goblet cells consists mainly of sulphated proteoglycans. Further, the results from the present lectin and neuraminidase tests suggest that these mucins contain much N‐acetylglucoseamines and some N‐acetylgalactosamines and sialic acid, but seem to lack glucose and mannose. They also contain some galactose‐N‐acetylgalactosamines sequences, normally hidden by sialic acid. The distinct brush border and mucus layer on the epithelial cells in the respiratory intestine may indicate some digestive roles, such as absorption of water, ions and simple carbohydrates. As sulphated proteoglycans are tough and attract much water, this mucus may play important roles in the protection against mechanical and chemical damages and in the defence against micro‐organisms throughout the entire intestine, but in the respiratory intestine it may impede significantly the oxygen uptake. However, as this part of the intestine usually contains no digesta, but is completely filled with air, frequently renewed by dry air from the atmosphere, and the main function of the mucus may be to protect the respiratory epithelium against a destroying and dangerous desiccation.  相似文献   

13.
Branchial epithelium of Pseudophoxinus antalyae was lined by both a thick stratified epithelium lining gill arches, gill rakers and primary filaments and a thin epithelium lining the lamellae. Mucous, chloride and rodlet cells, interspersed between pavement cells, were present in the branchial epithelium. With histochemical procedures for the characterization of glycoconjugates, mucous cells showed a strong positive reaction with Periodic acid-Shiff and Alcian Blue at pH 2.5, although with Alcian Blue at pH 0.5 and pH 1.0 the reaction was much weaker. When the combined Alcian Blue (pH 2.5) – Periodic acid-Shiff reaction was performed, most mucous cells were stained purple, whereas by the combined Aldehyde Fuchsin/Alcian Blue (pH 2.5), most cells showed a positive reaction only to Aldehyde Fuchsin. Methylation/ Alcian Blue (pH 2.5) and Methylation/ Saponification/ Alcian Blue (pH 2.5) methods showed the presence of sulphated and carboxylated glycoconjugates in mucous cells. Mucous cells were also detected to stain all metachromatically with Toluidine Blue.  相似文献   

14.
Mucin hypersecretion is considered to be one of the most common components of the immune response to gastrointestinal nematode infection. However, investigations have not been conducted in the Cattle–Cooperia oncophora system to verify the findings largely derived from murine models. In this study, we examined the expression of seven mucins and seven enzymes in the mucin biosynthesis pathway involved in O-linked glycosylation in the bovine small intestine including goblet cells enriched using laser capture microdissection during a primary C. oncophora infection. At the mRNA level, MUC2 expression was significantly higher in both lamina propria and goblet cells at 28 days post-infection compared to the naïve control. MUC5B expression at the mRNA level was also higher in lamina propria at 28 dpi. Expression of MUC1, MUC4, MUC5AC, and MUC6 was extremely low or not detectable in goblet cells, columnar epithelial cells, and lamina propria from both naïve control and infected animals. Among the seven enzymes involved in post-translational O-linked glycosylation of mucins, GCNT3, which may represent one of the key rate-limiting steps in mucin biosynthesis, was up-regulated in goblet cells, columnar epithelial cells, lamina propria, and gross small intestine tissue during the course of infection. Western blot analysis revealed that MUC2 glycoprotein was strongly induced by infection in both gross small intestine tissue and its mucosal layer. In contrast, the higher MUC5B protein expression was observed only in the mucosal layer. Immunohistochemistry provided further evidence of the mucin glycoprotein production and localization. Our results provided insight into regulation of mucin biosynthesis in various cell types in the bovine small intestine during gastrointestinal nematode infection and will facilitate our understanding of mucins and their role in immune response against parasitic nematodes.  相似文献   

15.
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.  相似文献   

16.
On the fine structure of the fetal goblet cells in the bovine small intestineEarly in the fetal development, i.e. at the time both of the growth of intestinal villi and crypts and the epithelial cell differentiation the goblet cells also appear. The maturation of goblet cells progresses during their migration from the base of the villi respectively of the crypts to the villous top. As in the bovine large intestine there are vesicles and capsulated vacuoles, which contain vesicles, as single elements or as conglomerates in the immature goblet cells of the small intestine. These images deliver a scenario of the mechanism of secretory granule production and probably play a role in the formation of mucus.  相似文献   

17.
Early in the fetal development, i.e. at the time both of the growth of intestinal villi and crypts and the epithelial cell differentiation the goblet cells also appear. The maturation of goblet cells progresses during their migration from the base of the villi respectively of the crypts to the villous top. As in the bovine large intestine there are vesicles and capsulated vacuoles, which contain vesicles, as single elements or as conglomerates in the immature goblet cells of the small intestine. These images deliver a scenario of the mechanism of secretory granule production and probably play a role in the formation of mucus.  相似文献   

18.
The morphology of the pancreatic duct system did not receive much attention as compared to the microanatomy of the exocrine and endocrine pancreas. The histological peculiarities of the excretory duct system are of major importance especially in laboratory animals like guinea pigs. The paper describes the histological peculiarities of the major interlobular and extrapancreatic ducts in guinea pigs. The pancreatic tissue samples were collected from five guinea pigs. For histological investigation, several pancreatic fragments underwent fixation in 10% buffered formalin and were later processed by the standard paraffin technique. Subsequentially, tissue sections were stained by Goldner's trichrome staining. The mucous substances were assessed by Alcian blue and Periodic acid–Schiff staining methods. The interlobular and main pancreatic ducts in the guinea pig present a simple columnar epithelium surrounded by a thick layer of dense connective tissue. The aforementioned epithelium of the main pancreatic ducts includes principal cells, goblet cells and basal cells. Additionally, the ductal epithelium presents occasional unicellular multiloculated intraepithelial mucous glands and prominent extraepithelial glands. The latter adopts a simple or compound tubular feature. The mucus elaborated by the three glandular types is mostly neutral in goblet cells, predominantly acidic in extraepithelial ductal glands, and a similar amount of acidic and neutral mucin in intraepithelial glands. In conclusion, the epithelium-associated mucous glands in the interlobular and main pancreatic ducts in the guinea pig are restricted not only to goblet cells. A substantial mucous discharge probably with a protecting role against irritative pancreatic juice derives from the main ductal intraepithelial and extraepithelial glands.  相似文献   

19.
Farmed fish are usually exposed to routine procedures which have strong effects on stress responses. Rodlet cells may represent an useful biomarker for studies on the presence of stressors in aquaculture. This work focused on the localization of rodlet cells by light and electron microscopy in gills of sea bass (Dicentrarchus labrax) subjected to different conditions of overcrowding. In general, a significant increase in number of rodlet cells has been observed in all animals subjected to overcrowding stress. In gills of control group rare rodlet cells were detected at the level of both primary and secondary lamellae, whereas in stressed group clusters of rodlet cells have been found in the epithelium of primary and secondary lamellae indicating that these cells are influenced by stocking density.  相似文献   

20.
The gill structure of the Amazonian fish Arapaima gigas (Cuvier 1829) shows ontogenetic changes during development, particularly due the transition from the aquatic to the obligatory air breathing mode of respiration. However, three main cell types can be found in the gills: mitochondrial rich cells, pavement cells and mucous cells (MCs). The MCs are involved in the secretory pathway. The functions of the secreted molecules include mechanical protection of epithelia, protection against parasites and bacterial infection, and role on ion regulation. In this study, we analysed mucous cell location and mucous cell type, based on pH, during the development of A. gigas. Using samples obtained from the environment, gills were collected and fixed in buffered solution. Histological techniques for the identification of MCs were performed Alcian Blue (AB) and periodic acid‐Schiff (PAS). The results showed the presence of PAS+ and AB+ cells in the whole filament in all examined fish. In animals less than 50 g, few MCs were present, and no differences were observed in AB+ and PAS+ cells. In animals weighing close to 500 g, more PAS+ cells than AB+ cells were observed, and in animals that weighed more than 1,000 g, more AB+ cells than PAS+ cells were observed. These observations may be a result of the ontogenetic changes in the gill epithelia, which can change the osmorespiratory compromise in ion regulation functions as well the glycosaminoglycans secreted by PAS cells, which in large animals can play a role in the protection against parasites and bacterial infection.  相似文献   

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