Influence of colonizing micro-flora on the mucin histochemistry of the neonatal mouse colon

Summary Mucin histochemistry on sections of colon from germ-free and conventional mouse pups showed that all goblet cell mucins were sulphated at birth. During the first two weeks of post natal development, the pattern of mucin production in the ascending colon changed to a distribution of non-sulphated mucins towards the apical zone of the crypts and sulphated sialomucins basally. In conventional animals during the third postnatal week when the complex micro-flora of the colon was becoming established, the typical adult mucin distribution pattern developed, with sulphated mucins now confined to the upper third of the crypt. However, in the absence of a colonizing micro-flora crypt mucins become more and more sulphated until at weaning, most goblet cells of the ascending colon were producing fully or partially sulphated mucins, except for one or two cells at the very base of the crypt.     

Secretory glycoproteins of major vestibular glands (Bartholin's glands) in female calves. Studies with usual histochemical methods and with lectin-horseradish peroxidase conjugates in normal animals and in animals implanted with anabolic drugs

The nature of mucins synthetized by the major vestibular glands of normal female calves and animals treated by anabolic drugs was investigated by usual histochemical methods and by lectin conjugate methods: Canavalia ensiformis (Con A), Limulus polyphemus (LPA), Lotus tetragonolobus (LTA), Arachis hypogaea (PNA), Ricinus communis (RCA I), Glycine max (SBA) and Triticum vulgaris (WGA). Two main secretory cell types, i.e. acinar and tubular cells, could be distinguished. The former produced sialomucins, whereas the latter produced neutral mucins. WGA and PNA showed strong binding to all secretory cells while LTA, RCA I and SBA exhibited a weaker affinity. Treatment with anabolic drugs enhanced O-acetyl sialic acid synthesis and we noted de novo synthesis of sulfomucins. However, the staining intensity of LTA was stronger than in control calves. Tubular secretory cells of treated animals revealed an intense secretion of neutral mucins but, in contrast, all tested lectins were less intensively bound. The present study provides additional histochemical information on Bartholin's glands. A shortened procedure is proposed to detect animals treated with anabolic drugs when morphological changes are lacking.     

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.     

Histochemical characteristics of mucins in the small intestine. A comparative study of normal mucosa, benign epithelial tumours and carcinoma

Synopsis The histochemical properties of the mucins in seven benign epithelial tumours and 15 carcinomas distributed along the duodenum, jejunum and ileum were investigated and compared with normal controls. This study reveals that (a) goblet cells in normal small intestine contain neutral and sialomucins but no sulphated material; (b) the proportion of the different types of mucins in the goblet cells vary along the crypts and villi with an increasing amount of sialomucins towards the villus top; (c) mucin composition also changes from duodenum to ileum particularly in the proportions of sialic acid types and in the presence of traces of sulphomucins in the ileal mucosa close to the ileo-caecal valve, suggesting a gradual transition through the small intestine to the colon; (d) benign tumours show the same mucin pattern as normal mucosa; (e) the mucosa adjacent to carcinoma shows increasing amounts of sialomucins and sulphomucins; (f) carcinomas present a variety of mucin patterns, and thus the study of mucins seems to be of no value in differentiating tumours of the small intestine from those elsewhere in the gastrointestinal tract. A working hypothesis based on the Unitary Theory of the origin of the intestinal epithelial cells is proposed to explain the variations in glycoprotein synthesis with cell differentiation and carcinogenesis.     

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.     

Mucous cells of the tracheobronchial tree in the ferret

Summary Mucosubstances in the tracheobronchial tree of the ferret were studied histochemically. The submucous glands contained predominantly neutral mucins. Scattered between these were cells containing sulphated mucins and sialidase-labile and sialidase-resistant sialomucins. Most of the goblet cells in the trachea, as well as those in the bronchi and large pronchioles, contained sulphated mucins. A smaller proportion of the goblet cells showed sialidase-labile and sialidase-resistant sialomucins. It will be interesting to see whether ferrets can be used to produce animal models for hypersecretory diseases such as cystic fibrosis and chronic bronchitis.     

Histochemical studies on the mucins of the vertebrate tongues

Summary With a view to augment the understanding of the tongue mucosubstances and their significance in the physiology of taste, tongues of two amphibians were investigated histochemically to determine the distribution and nature of the mucosubstances by employing recent techniques, and the results were considered comparatively with the tongue mucins of other vertebrates and the animal mucosubstances in general. A heterogenous distribution of neutral mucins, sulfomucins and sialomucins in fungiform and filiform papillae, ventral epithelium, lingual glands and connectives tissue could be significantly noted on the basis of which various cell types having specialised mucosubstances were identified in the papillae and the ventral epithelium.The tongue mucosubstances, especially sulfomucins and sialomucins, exhibited inharent heterogenity. Sulfomucins at some sites were hyaluronidas-labile and at other hyaluronidaseresistant, their azurophilia especially at low pH was also different, some being azurophilic and others nonazurophilic. Sialomucins also exhibited such heterogenity, at some sites they were labile to acid hydrolysis and mild methylation but in others they were resistant to the latter, though sialomucins at both sites were sialidase-labile. The mucosubstances localised in the serous glands were highly typical, since they exhibited extraordinary histochemical reactions, they possessed intensely PAS positive reactivity resistant to diastase, hyaluronidase and sialidase, negative to alcian blue both at pH 1 and 2.5, and exhibited no metachromasia at both low and high pH levels, but showed alcianophilia only at high pH levels. Such high pH alcianophilia was sialidase and hyaluronidase resistant but labile to mild methylation. These mucosubstances bear some similarity to those of mammalian parotid.Such heterogenity was reflected at species-specific level, since some interesting speciesspecific differences were observed in mucosubstances of histologically identical cells and tissues of tongues of the two species of amphibians which might assist in the elucidation of phylogenetic importance of mucins.This investigation forms a part of Ph. D. Thesis to be submitted by Mr. M. N. Nalavade to Shivaji University, Kolhapur, under the guidance of Dr. A. T. Varute.     

Mucous cells of the tracheobronchial tree in the ferret

Mucosubstances in the tracheobronchial tree of the ferret were studied histochemically. The submucous glands contained predominantly neutral mucins. Scattered between these were cells containing sulphated mucins and sialidase-labile and sialidase-resistant sialomucins. Most of the goblet cells in the trachea, as well as those in the bronchi and larger bronchioles, contained sulphated mucins. A smaller proportion of the goblet cells showed sialidase-labile and sialidase-resistant sialomucins. It will be interesting to see whether ferrets can be used to produce animal models for hypersecretory diseases such as cystic fibrosis and chronic bronchitis.     

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.     

Microstereological and histochemical studies of the salivary glands of the giant rat (Cricetomys gambianus, waterhouse)

The histology and histochemistry of the parotid, submandibular and sublingual glands were studied. The submandibular gland contained only serous acini as in the guinea pig, but unlike in many other mammals. The parotid gland contained only serous acini while the sublingual gland was mixed, mucous acini being the predominant secretory tissue interspersed by a few serous acini. Serous demilunes also commonly formed caps on the mucous acini. The ducts of the gland contributed over 30% of the volume of the submandibular gland, while those of the parotid and sublingual glands formed about 12 and 10% of the gland, respectively. The secretions of the parotid gland, as judged by histochemical methods, contained neutral mucins and some sialomucins. Neutral mucins, sulphomucins and sialomucins were detected in both the submandibular gland and sublingual gland.     

Histochemical observations on the mucins of the gastrointestinal tract in the toad (Bufo melanostictus).

The pattern of mucin secretion of the gastrointestinal tract of the toad (B. melanostictus) was investigated by histochemical methods. The goblet cells of the oesophagus secreted mainly acid mucins which were sialomucins, while the cells lining the surface of the stomach produced neutral mucins only. Goblet cells of the small intestine and cloaca secreted acid mucins, which were predominently sulphated mucins.     

Fine structure of the mandibular gland in crest-tailed marsupial-rat (Dasyuroides byrnei)

The mandibular glands of Dasyuroides byrnei were examined by light microscopy, and transmission and scanning electron microscopy. The secretory units consisted of numerous seromucous acini and a few seromucous demilunes. The seromucous acini were almost always capped by demilunes. The acinar seromucous cells contained faintly basophilic, light, coarse, bipatite secretory granules with matrix of low and moderate densities. The demilunar cells were dark compared with acinar seromucous cells and contained acidophilic secretory granules with a fibrillogranular matrix of moderate density. Preacinar cells with a seromucous nature were occasionally present at the junction between the acinus and intercalated duct. These cells had numerous basophilic granules, which were similar to those of acinar seromucous cells. The intercalated ducts consisted of simple cuboidal light cells that had a few small electron-dense granules. The striated ducts were composed of tall columnar light cells containing numerous vesicles, but no secretory granules. The mandibular acini of D. byrnei were composed of two cell types having a seromucous nature, unlike those of the opossum and many other mammals.     

Histochemical and ultrastructural studies on the salivary glands of Helix aspersa (Mollusca)

A histochemical and ultrastructural study was carried out on the salivary glands of adult specimens of Helix aspersa. Histochemically four cell types were distinguished: mucocyte I, mucocyte II, pseudochromosome cell and protein cell. The first secretes neutral and acid mucins. Mucocyte II and pseudochromosome cells produce acid mucins and the protein cell secretes neutral mucins and proteins.
The ultrastructural data for differentiating these four cell types is discussed. Mucocytes I have a characteristic arrangement of rough endoplasmatic reticulum and basal infoldings. Mucocytes II have pseudocrystalline formations in the rough endoplasmatic reticulum and intraluminary ducts. Pseudochromosome cells have typical granules with a reticular central zone. Protein cells have serous homogenous secretion.
The epithelium of the salivary ducts is described.     

Histochemical study on the tongue of Rana ridibunda (anuran amphibian)

A structural and histochemical study of the tongue in the Anuran Amphibian Rana ridibunda was carried out. Histochemical analysis of the filiform and fungiform papillae of the dorsal epithelium has shown a variety of cellular types which may be characterized cytochemically. All of them, except the goblet cells, show a remarkable amount of neutral mucins. The intensity of histochemical positive reaction for sulphomucins, sialomucins and protein is variable according to the cell type. Other histochemical reactions show that the lingual glands are rich in neutral mucins, but not in sialomucins. Histochemically in the component the basic proteins with sulphydryl groups are demonstrated. This sulphydryl groups are more abundant in the glands located in the deep regions.     

Histochemistry of glycoconjugates in the skin of the bovine muzzle, with special reference to glandular structures

The distribution of glycoconjugates in the muzzle of young adult Holstein cows has been studied by means of selected light-microscopic histochemical methods, including lectin histochemistry. In the skin layers, strong reactions were confined to intercellular substances in between the cells of the vital epidermis, exhibiting neutral glycoconjugates mainly with alpha-D-galactosyl and N-acetyl-D-galactosaminyl residues. In the nasolabial glands, distinctly positive staining for neutral glycoproteins with various saccharide residues (alpha-D-galactose, alpha-N-acetylgalactosamine, D-galactose-beta(1----3)D-N-acetylgalactosamine, beta-D-galactose), and for smaller amounts of acidic glycoconjugates, was found in the secretory cells and the luminal secretion. The cells of the excretory duct system showed weak to moderate reactions (alpha-D-galactose, beta-D-galactose), only the collecting ducts reacted positively for acidic glycoproteins with sialyl residues. The results obtained are discussed in view of muzzle function, with special reference to the salivary nature of the secretion of bovine nasolabial glands.     

Fine structure of the parotid gland in the crest-tailed marsupial-rat (Dasyuroides byrnei).

The parotid gland of Dasyuroides byrnei was examined by light microscopy, and transmission and scanning electron microscopy. The acini were composed predominantly of seromucous cells with a few mucous cells. The seromucous cells were light or dark cells containing acidophilic spherical granules of moderate to high electron density and had well-developed cytoplasmic organelles-ordinary mitochondria and large mitochondria with tubular cristae, RER with vesicular or tubular elements, and Golgi apparatus with lamellae, vesicles and vacuoles. The mucous cells had basophilic amorphous granules of low electron density, like those of ordinary mucous cells. The intercalated ducts were composed of simple cuboidal light cells having a few electron-dense granules. The striated ducts consisted of tall columnar light cells containing numerous vesicles and mitochondria with tubular cristae, the same as found in acinar seromucous cells.     

Histochemical observations on the female reproductive tract of bats. IV. Mucopolysaccharides in the uterus of three species of bats

The three species of bats studied show glycogen, neutral, sialo- and sulfomucins in the cells of the uterine epithelium and glands. Elaboration of these mucins occurs during anestrus in Pteropus giganteus and during proestrus in Taphozous longimanus. In Megaderma lyra lyra only glycogen is observed during anestrus and proestrus. Neutral, and sialomucins in addition to glycogen are observed during estrus. The concentration of these mucins increases progressively and is maximum at the time of implantation, decreasing thereafter in all the three species of bats. The elaboration and increase of mucins is probably under the influence of hormones of the ipsilateral ovary.     

Immunolocalization of PTHrP in the submandibular glands of three rodent species.

The present study deals with immunohistochemical localization of PTHrP in bank vole, pine vole and white mouse submandibular glands. PTHrP immunoreactivity was observed in epithelial cells of all ductal segments (intercalated, striated, interlobular and main excretory ducts) of the salivary glands in all the three animal species tested. We also found PTHrP expression in myoepithelial cells surrounding the mucous alveoli of submandibular glands in those animals. The reaction was less intense than that found in the epithelial cells of excretory ducts. We occasionally observed a very slight positive reaction for PTHrP in smooth muscle cells of small blood vessels. We also found PTHrP expression in the neurons of ganglion in the submandibular gland.     

Distribution of aquaporin 1 in the rat pancreatic duct system examined with light- and electron-microscopic immunohistochemistry

The pancreatic duct is the major site for the secretion of pancreatic fluid, but the pathway of water transport in this system is not known. Recently, intense signal for mRNA of aquaporin 1 (AQP1) water channels was detected in isolated rat interlobular ducts. Therefore, we performed light- and electron-microscopic (EM) immunohistochemistry for AQP1 in the rat pancreatic ducts. AQP1 immunoproducts were not observed in the acinar cells, centroacinar cells or intercalated ducts. In the smaller intralobular ducts less than 10 microm in diameter (the lumen plus duct cells), most cells were immunonegative. AQP1-positive cells appeared in intralobular ducts 10-15 microm in diameter. In small and medium-sized interlobular ducts 15-70 microm in diameter surrounded by periductal connective tissue 2-40 microm thick, most cells were AQP1 positive with various degrees of immunoreactivity. In the larger interlobular ducts, the expression of AQP1 was variable, ranging from immunopositive to negative. In the main pancreatic duct, most cells were negative for AQP1. EM immunohistochemistry of the intralobular and small interlobular ductal epithelial cells showed that the AQP1 immunoproducts were more abundant in the basolateral membrane than in the apical membrane, though they were present in both membranes. In the medium-sized interlobular ducts, AQP1 immunoproducts were distributed densely along the apical, lateral interdigitation and basal membrane of the epithelial cells. In the various sizes of interlobular ducts, immunoproducts were associated not only with the plasma membrane, but also with the caveolae and vesicle-like structures. Secretin did not induce any significant difference in AQP1 expression and cellular and subcellular localization. These results indicate that the expression and subcellular localization of AQP1 vary considerably depending on the duct size, which may reflect water transport characteristics in the different divisions of the pancreatic duct system.     

Importance of acidic mucin secretions by foveolar and mucous neck cells of rat fundic mucosa as the defence mechanisms against HCl as revealed by fasting.

The localization of neutral mucin and acidic mucins in both control and fasted rat gastric fundic mucosa were examined by microscopic and electron microscopic histochemical methods. By Carnoy's fixation, the surface mucous coat of the control rat gastric fundic mucosa was found to be composed of alternating layers of acidic mucins and neutral mucin, indicating the synchronous and cyclic secretions of them. In many gastric pits of the fundic glands, the acidic mucins were found to spring out from the deep foveolar regions like volcanoes. This phenomenon may suggest that the acidic mucins play a fundamental role in protecting the pit cells against HCl during its passage, and the layers of neutral mucin and acidic mucins in the surface coat is the safeguard against the HCl and digestive enzymes in the gastric lumen. In the fasting rat gastric fundic mucosa, the acidity and the amount of the gastric juice were markedly decreased, indicating the suppressed secretions of mucins and HCl. The decreased production of sulfomucin was directly demonstrated by 35SO4-autoradiography. Many mucous neck cells existing in close association with the parietal cells were ballooned due to accumulation of alcian blue (AB)-positive but high iron-diamine (HID)-negative sialomucin, which was not demonstrable in the control. The secretory granules of sialomucin contained in the ballooned mucous neck cells were positively stained ultrastructurally with cacodylate-ferric colloid to stain acid mucopolysaccharides.