Histochemical detection of glycogen using Griffonia simplicifolia agglutinin II

Polymicrobial Biofilm Interaction Between Histophilus somni and Pasteurella multocida

Histophilus somni and Pasteurella multocida are two of multiple agents responsible for bovine respiratory disease (BRD) in cattle. Following respiratory infection of calves with H. somni, P. multocida may also be isolated from the lower respiratory tract. Because H. somni may form a biofilm during BRD, we sought to determine if P. multocida can co-exist with H. somni in a polymicrobial biofilm in vitro and in vivo. Interactions between the two species in the biofilm were characterized and quantified by fluorescence in situ hybridization (FISH). The biofilm matrix of each species was examined using fluorescently tagged lectins (FTL) specific for the exopolysaccharide (EPS) using confocal laser scanning microscopy. Bacterial interactions were determined by auto-aggregation and biofilm morphology. Pasteurella multocida and H. somni were evenly distributed in the in vitro biofilm, and both species contributed to the polymicrobial biofilm matrix. The average biomass and biofilm thickness, and the total carbohydrate and protein content of the biofilm, were greatest when both species were present. Polymicrobial bacterial suspensions auto-aggregated faster than single species suspensions, suggesting physical interactions between the two species. Almost 300 P. multocida genes were significantly differentially regulated when the bacteria were in a polymicrobial biofilm compared to a mono-species biofilm, as determined by RNA-sequencing. As expected, host genes associated with inflammation and immune response were significantly upregulated at the infection site following H. somni challenge. Encapsulated P. multocida isolates not capable of forming a substantial biofilm enhanced an in vitro polymicrobial biofilm with H. somni, indicating they contributed to the polymicrobial biofilm matrix. Indirect evidence indicated that encapsulated P. multocida also contributed to a polymicrobial biofilm in vivo. Only the EPS of H. somni could be detected by FTL staining of bovine tissues following challenge with H. somni. However, both species were isolated and an immune response to the biofilm matrix of both species was greater than the response to planktonic cells, suggesting encapsulated P. multocida may take advantage of the H. somni biofilm to persist in the host during chronic BRD. These results may have important implications for the management and prevention of BRD.

Biofilm formation and avian immune response following experimental acute and chronic avian cholera due to Pasteurella multocida

Pasteurella multocida is the causative agent of avian cholera, an important economic and ecological disease that can present as a peracute, acute, chronic, or asymptomatic infection. Acute avian cholera is associated with encapsulated P. multocida, while chronic and asymptomatic cases of avian cholera may be associated with capsule-deficient P. multocida isolates. We hypothesize that biofilm formation is also associated with chronic and asymptomatic avian cholera. Experimental infections of chickens with encapsulated, biofilm-deficient P. multocida strain X73, proficient biofilm forming P. multocida strain X73ΔhyaD, and proficient biofilm forming clinical strains 775 and 756 showed that virulence was inversely correlated with biofilm formation. Biofilm-proficient isolates induced chronic avian cholera in the chicken host. Histopathological analysis was used to show that biofilm-proficient isolates induced little inflammation in the lungs, heart, and liver, while biofilm-deficient isolates induced greater inflammation and induced the recruitment of heterophil granulocytes. Putative biofilm matrix material and exopolysaccharide was detected in pulmonary tissue of chickens diagnosed with chronic avian cholera using scanning electron microscopy and a fluorescently-tagged lectin, respectively, supporting a role for biofilm in chronic avian cholera. P. multocida induced Th1 and Th17 immune responses during acute and chronic avian cholera, as determined by quantitative real-time PCR of splenic cytokine genes. Chickens that succumbed to acute avian cholera after experimental challenge with strain X73 had high levels of INF-γ, IL-1β, IL-6, IL-12A, IL-22, IL-17A, and IL-17RA expressed in the spleen compared to all other experimental groups. Birds infected with capsule-deficient strains had chronic infections lasting 7 days or longer, and had increased levels of IL-17RA, CCR6, and IL-16 compared to non-infected control chickens. However, specific antibody titers increased only transiently to capsule-deficient strains and were low, indicating that antibodies are less important in managing and clearing P. multocida infections.

New insight into the role of MMP14 in metabolic balance

Membrane-anchored matrix metalloproteinase 14 (MMP14) is involved broadly in organ development through both its proteolytic and signal-transducing functions. Knockout of Mmp14 (KO) in mice results in a dramatic reduction of body size and wasting followed by premature death, the mechanism of which is poorly understood. Since the mammary gland develops after birth and is thus dependent for its functional progression on systemic and local cues, we chose it as an organ model for understanding why KO mice fail to thrive. A global analysis of the mammary glands' proteome in the wild type (WT) and KO mice provided insight into an unexpected role of MMP14 in maintaining metabolism and homeostasis. We performed mass spectrometry and quantitative proteomics to determine the protein signatures of mammary glands from 7 to 11 days old WT and KO mice and found that KO rudiments had a significantly higher level of rate-limiting enzymes involved in catabolic pathways. Glycogen and lipid levels in KO rudiments were reduced, and the circulating levels of triglycerides and glucose were lower. Analysis of the ultrastructure of mammary glands imaged by electron microscopy revealed a significant increase in autophagy signatures in KO mice. Finally, Mmp14 silenced mammary epithelial cells displayed enhanced autophagy. Applied to a systemic level, these findings indicate that MMP14 is a crucial regulator of tissue homeostasis. If operative on a systemic level, these findings could explain how Mmp14KO litter fail to thrive due to disorder in metabolism.

A simple histochemical method for the identification of cytotrophoblasts in tissue sections

A simple method for the demonstration of placental cytotrophoblast cells is described, utilising the affinity of the lectin from Bandeiraea simplicifolia-II (BSA-II) for intracellular amylase-sensitive glycogen and a protocol using biotinylated BSA-II followed by an avidin-peroxidase revealing system. In early pregnancy, cytotrophoblast cells in chorionic and anchoring villi are deeply stained and with ongoing differentiation the staining gradually decreases in intensity, suggesting that this lectin can be a useful marker for these cells.

Decrease of sialic acid residues as an eat-me signal on the surface of apoptotic lymphocytes

The silent clearance of apoptotic cells is essential for cellular homeostasis in multicellular organisms, and several mediators of apoptotic cell recognition have been identified. However, the distinct mechanisms involved are not fully deciphered yet. We analyzed alterations of the glycocalyx on the surfaces of apoptotic cells and its impact for engulfment. After apoptosis induction of lymphocytes, a decrease of α2,6-terminal sialic acids and sialic acids in α2,3-linkage with galactose was observed. Similar changes were to be found on the surface of apoptotic membrane blebs released during early stages of apoptosis, whereas later released blebs showed no impaired, but rather an increased, exposure of sialic acids. We detected an exposure of fucose residues on the surface of apoptotic-cell-derived membrane blebs. Cleavage by neuraminidase of sialic acids, as well as lectin binding to sialic acids on the surfaces, enhanced the engulfment of apoptotic cells and blebs. Interestingly, even viable lymphoblasts were engulfed in an autologous cell system after neuraminidase treatment. Similarly, the engulfment of resting apoptotic lymphocytes was augmented after neuraminidase treatment. However, the engulfment of resting viable lymphocytes was not significantly enhanced after neuraminidase treatment. Our findings support the importance of the glycocalyx, notably the terminal sialic acids, in the regulation of apoptotic cell clearance. Thus, depending on cell type and activation status, changes in surface glycosylation can either directly mediate cellular engulfment or enhance phagocytosis by cooperation with further engulfment signals.

Lectin-histochemistry: glycogenosis in cattle

Ten out of 47 calves that were born in a small Brahman herd from southern Brazil developed progressive muscular weakness and tremors, lethargy and poor body condition. Necropsy was performed on three affected animals. The only gross lesion detected was paleness of the muscles of the trunk and limbs. Multiple cytoplasm vacuoles located in different tissues were the principal microscopic lesions. Vacuoles were particularly evident in skeletal muscles and myocardium. PAS-positive granules were numerous in skeletal muscle fibres and Purkinje fibres of the myocardium, but were also observed in the neurons of the brain and spinal cord, and in the vascular smooth muscle fibres from all the examined tissues. Pretreatment with diastase completely abolished the PAS reactivity. The vacuoles reacted strongly to Griffonia simplicifolia II and Concanavalia ensiformes lectins, whose biding pattern has been reported as useful for demonstration of glycogen. Examination of the electron micrographs revealed that glycogen was free within the cytoplasm or accumulated in membrane-bound granules of several tissues, especially in striated muscle, liver and neurons of the CNS. These findings were consistent with generalized glycogenosis.

Glycoconjugate distribution in early human notochord and axial mesenchyme

Glycosylation patterns of cells and tissues give insights into spatially and temporally regulated developmental processes and can be detected histochemically using plant lectins with specific affinities for sugar moieties. The early development of the vertebral column in man is a process which has never been investigated by lectin histochemistry. Therefore, we studied binding of several lectins (AIA, Con A, GSA II, LFA, LTA, PNA, RCA I, SBA, SNA, WGA) in formaldehyde-fixed sections of the axial mesenchyme of 5 human embryos in Carnegie stages 12-15. During these developmental stages, an unsegmented mesenchyme covers the notochord. Staining patterns did not show striking temporal variations except for SBA which stained the cranial axial mesenchyme only in the early stage 12 embryo and for PNA, of which the staining intensity in the mesenchyme decreased with age. The notochord appeared as a highly glycosylated tissue. Carbohydrates detected may correspond to adhesion molecules or to secreted substances like proteoglycans or proteins which could play an inductive role, for example, for the neural tube. The axial perinotochordal unsegmented mesenchyme showed strong PNA binding. Therefore, its function as a PNA-positive "barrier" tissue is discussed. The endoderm of the primitive gut showed a lectin-binding pattern that was similar to that of the notochord, which may correlate with interactions between these tissues during earlier developmental stages.

Pigeon fanciers' lung: identification of disease-associated carbohydrate epitopes on pigeon intestinal mucin

Pigeon intestinal mucin, a complex high molecular weight glycoprotein, is a key antigen in the development of pigeon fanciers' lung (PFL). We have studied the specificity of antibodies to mucin in patients with PFL and asymptomatic antibody-positive individuals. Extensive papain digestion, which removes the non-glycosylated regions of the mucin leaving the heavily glycosylated 'bottle brush' regions, resulted in a 600-fold decrease in IgG3 antibody titres with little effect on IgG1 and IgG2 titres. This suggests that IgG1 and IgG2 are directed against the region rich in O-linked sugar chains whilst the majority of the IgG3 is directed against epitopes which are proteinase-sensitive. Lectin mapping of the carbohydrates present on pigeon intestinal mucin demonstrated high levels of exposed N-acetyl neuraminic acid, N-acetyl galactosamine and N-acetyl glucosamine, with lower levels of fucose and some galactose. Sera from pigeon fanciers inhibited binding of lectins specific for N-acetyl neuraminic acid, N-acetyl galactosamine, internal N-acetyl glucosamine and fucose. Sera from people with PFL, compared with sera from asymptomatic antibody-positive fanciers, had significantly higher titres of antibody that inhibited binding of four lectins specific for N-acetyl galactosamine and one fucose-specific lectin, suggesting that these sugars may play a dominant role in disease-associated epitopes. The results suggest that different IgG subclasses recognize different epitopes on mucin and that the epitopes recognized by the major subclasses are present on the O-linked oligosaccharides. Further, the carbohydrate-specific anti-mucin antibodies produced by PFL patients may differ in their specificity from those found in asymptomatic individuals.

Expression patterns of complex glycoconjugates and endogenous lectins during fetal development of the viscerocranium

Experimental evidence suggests that carbohydrates and their corresponding receptors (endogenous lectins) decode biological information. Therefore, the expression of complex oligosaccharides--the potential ligand part of this recognition system--during chondrogenesis and osteogenesis was determined in the viscerocranium of fetal rats by mapping the staining patterns of exogenous lectins. Results were compared with the expression of bone- and/or cartilage-specific core proteins and the binding profiles of neoglycoconjugates. These synthetic tools make possible the localization of sugar-ligand-binding sites. The spatial and temporal distribution patterns of glycoconjugates were highly dynamic and demonstrated a clear correlation with characteristic morphological modifications. The glycobiological characterization of precartilage mesenchymal cells revealed distinct differences compared to prospective bone anlagen. Especially the binding of the exogenous lectin from Griffonia simplicifolia II, that selectively visualized prechondral aggregations, reveals that regulation of early chondral growth is at least phenomenologically correlated with a relatively atypical oligosaccharide composition terminating with N-acetylglucosamine.

Lectin histochemistry in rat liver fibrosis induced by heterologous serum sensitization

The localization of carbohydrates in rat livers with fibrosis induced by heterologous serum was examined by lectin histochemical and biochemical techniques. Twenty-four lectins were used to visualize the different carbohydrates in paraffin sections of normal and fibrotic liver tissues. No differences in staining patterns of these lectins were observed between normal and fibrotic livers in hepatocyte cell membranes including bile canaliculi, sinusoidal endothelial, or bile ductal cells. Kupffer cells strongly stained with Vicia villosa agglutinin (VVA) were seen only in the periportal zone of the normal liver, but they were observed in the periportal zone and scattered throughout the pseudolobular zone in the fibrotic liver. The cytoplasm of some hepatocytes was strongly stained by Bandeiraea simplicifolia lectin-I (BSL-I). BSL-I positive hepatocytes in normal liver were localized in the periportal zone, but those in the fibrotic liver were scattered in the periportal and perifibrous zones. After polyacrylamide gel electrophoresis of liver glycoproteins, differences in molecular sizes of BSL-I positive glycoproteins (79 and 81 kD) were detected by lectin blotting. Cell density of perifibrous BSL-I positive hepatocytes may be useful as a diagnostic parameter for liver fibrosis and/or cirrhosis. Two distinct staining patterns with twelve lectins were observed in fibrotic septa of the fibrotic liver. The fibrotic septa were stained with six characteristic lectins, and the centrilobular septa were stained with all these twelve of lectins. Histopathological assessment of the centrilobular fibrotic septa stained with these characteristic lectins may contribute to the diagnosis and prognosis of hepatic fibrosis.

Distribution and evaluation of complex carbohydrates in the quail collecting ducts

The cell heterogeneity within the collecting duct epithelium of quail kidney was investigated using histochemical methods for complex carbohydrates. The selective distribution of acidic glycoconjugates allowed further discrimination between metachromatic, mucin-secreting cells and dark, proton-transporting cells. Enzymatic digestion by glycosidases was performed to characterize the carboxylated and sulphated glycoconjugates of mucin-secreting cells. The staining intensity of all histochemical reactions with and without prior treatment, was quantitated by means of scanning histophotometry and differences in absorbance values were evaluated by statistical analysis. A different distribution of sulphated components was found for the mucin-secreting cells of renal cortex and medulla, suggesting a morphofunctional heterogeneity within mucin-secreting cell population.

Distribution patterns in glycoconjugate expression during the development of the rat palate

The distribution of complex carbohydrate structures during the embryonic development of the rat palate was analysed by examining lectin-binding patterns in serial paraffin and cryostat sections. With few exceptions, the binding patterns showed a general increase in lectin receptors in the more developed stages of palatogenesis. High mannose oligosaccharides were especially amplified during development. Terminal fucose molecules were not expressed. In contrast, terminal sialic acid molecules were ubiquitously distributed in epithelial and mesenchymal tissues. Non-sialylated terminal N-acetylglucosamine was specifically restricted to evolving bone matrix. Before palatal fusion, quantitative but not qualitative differences were detected between oral, nasal, and medial-edge epithelial surfaces. The only exception was LCA, which specifically marked epithelial cells at the tip of palatal shelves. A very selective affinity for Jacalin was demonstrated in the oral epithelium of the palate after day 16, suggesting the presence of sialylated terminal galactose-(beta-1,3)-N-acetylgalactosamine. PNA specifically marked the basal lamina of the oral side of palatal processes. The binding patterns of DBA, GSL IA, SBA, and VVA indicated that the epithelium of the tongue is characterized by terminal alpha- and beta-galactose residues, whereas palatine cells possess only molecules with beta-anomery. During palatogenesis, glycosaminoglycans patterns were significantly modified. Our data suggest that alteration of complex carbohydrate structures may play a central role in modulating cell-cell and cell-matrix interactions. The significance of these findings, however, remains to be elucidated.

Selective lectin-binding sites of primordial germ cells in chick and quail embryos

To ascertain the histochemical characteristics of surface carbohydrates on avian primordial germ cells (PGC), we examined the distribution of binding sites for several biotinylated lectins in chick and quail embryos. Some binding sites were detected almost selectively with PGC but not with other embryonic sites. Of these, lectin from Sojanum tuberosum (STA) reacted with PGC in both avian species, whereas lectin from Wistaria floribunda (WFA) and Griffonia simplicifolia II (GS-II) reacted in the quail and the chick, respectively. The binding site for STA was found at the cell surface and cytoplasm of the PGC from their initial appearance in the germinal crescent through migration to sexually indifferent gonads, whereas the WFA reaction was seen at stages before and during migration. These reactivities showed most intensely on the surface of PGC at the peak of their migration. In contrast, GS-II binding site was restricted to the cytoplasm, and its distribution was similar to that of the periodic acid-Schiff (PAS)-positive glycogen granules in chick PGC. These results suggest that some selective binding sites on the PGC surface play a significant role in their migration and show that lectins STA, WFA, and GS-II can be used as probes for identification of the avian PGC.

Histomorphological and cytochemical changes induced in the liver of goldfish Carassius carassius var. auratus by short-term exposure to lead

The cellular and molecular effects of experimental lead intoxication (5 mg l-1/24 h and 48 h) were studied in hepatocytes of Carassius carassius var. auratus. Significant lead storage was not detected by atomic absorbance spectroscopy after treatment. Cell morphology appeared only poorly impaired. A decrease of glycogen content was observed. Glycolysis, Krebs cycle and pentose shunt were altered in their enzymatic activities. Lysosomal activities were strongly increased. All enzymatic activities tested were altered 24 h after lead treatment.

Histochemical and cytochemical localization of blood group antigens

The oligosaccharide structures of blood group antigens are not the primary gene products; they are constructed in a stepwise manner by adding particular sugar to precursor oligosaccharides via several glycosyltransferases coded for by different blood group genes (Watkins 1966, 1978, 1980). Consequently, final profiles of antigens expressed in each cell type are influenced by many different factors such as the intrinsic composition of glycosyltransferase species which are defined by the genotype of the individuals, relative activity or amount of these enzymes (repression, derepression or induction of the enzymes), competition between enzymes with overlapping substrate specificity, the organization of the enzymes in membranes, utilizability of precursors and specific substrate sugars, and the activity level of degradating enzymes. Changes in the antigen profiles during maturation, differentiation and malignant transformation are thought to be intimately related to the variability of these factors. Although great importance attaches to histo- and cytochemical information on the distribution and levels of glycosyltransferases and messenger RNA corresponding to the relevant enzyme, detailed and precise localization of the blood group antigens and their variants is the base line for analyzing these complex factors. On the basis of individual genotype and histochemical findings about the antigen distribution and the interrelationship between cells and cellular components producing different antigenic structures (cellular and subcellular mosaicism), we can deduce precursor oligosaccharide levels as well as the status of gene activation and its primary product, glycosyltransferases. Thus, these findings are a prerequisite for further analysis at the molecular genetic level. As emphasized in this article, lectin staining or immunostaining methods with MAbs combined with glycosidase digestion procedures are powerful tools for in situ analysis of carbohydrate structures in histochemical systems. Although in some cases valuable results have been obtained by applying the technique, our knowledge concerning the distribution of complex carbohydrate structures is still far from satisfactory. Along with well defined MAbs and lectins, the key to developing our methods further is successful introduction of glycosidases, in particular, endoglycosidases since these reagents are indispensable for analyzing the inner core structures and glycoconjugate species of the blood group antigens. Application of these techniques at the ultrastructural level is an alluring possibility, even though many difficulties must be overcome. Although their functional roles have not yet been determined, a diverse array of macromolecules is known to be decorated with blood group-related antigens.(ABSTRACT TRUNCATED AT 400 WORDS)

Lectin binding in skeletal muscle. Evaluation of alkaline phosphatase conjugated avidin staining procedures

Cryostat sections from rat gracilis muscles were incubated with different biotinylated lectins: Con A (Concanavilin A), WGA (Wheat germ agglutinin), SBA (soybean agglutinin), GS I and GS II (Griffonia simplicifolia agglutinin), LCA (Lens culinaris agglutinin), PNA (peanut agglutinin) and PSA (Pisum sativum agglutinin). The sections were subsequently treated with alkaline phosphatase conjugated avidin. The lectin binding sites were visualized after incubation in substrate media containing: (1) 5-bromo-4-chloro indoxyl phosphate and Nitro Blue tetrazolium or copper sulphate; (2) naphthol AS-MX phosphate or naphthol AS-BI phosphate and various types of diazonium salts; (3) alpha-naphthylphosphate and Fast Blue BB; (4) beta-glycerophosphate according to the method of Gomori. The results obtained with the alkaline phosphatase methods were compared with those seen with a streptavidin-horseradish peroxidase procedure. Several chromogen protocols for visualizing alkaline phosphatase activity showed differences in the ability to detect lectin binding sites. A sarcoplasmic reaction was evident for Con A, GS II, WGA, LCA, and PSA after incubation in the indoxyl phosphate medium. Sarcoplasmic reaction for GS II was also noticed after incubation with naphthol AS-MX Fast Blue BB and beta-glycerophosphate. The latter substrate also gave rise to a sarcoplasmic Con A reaction. With the indoxylphosphate tetrazolium salt method some muscle fibres showed a very strong intracellular reaction after incubation with Con A and GS II while the staining intensity was weak in other fibres. The same muscle fibres were stained with PAS. No sarcoplasmic reactions were observed with either naphthol phosphate media or with the diaminobenzidine peroxidase methods. Further, the staining of the muscle fibre periphery, connective tissue, an capillaries was intensified using the indoxyl method. The indoxylphosphate-tetrazolium salt method seems to be suitable for future investigations of lectin binding sites in muscle sections.

Comparison of glycoconjugates at the surface of developing type II pneumocytes and Clara cells

The apical surface coat of type II pneumocytes and Clara cells in pre- and post-natal rat lung was examined with lectin histochemical methods. Lectins from Helix pomatia (HPA), peanut (PNA) and Maclura pomifera (MPA) were conjugated with horseradish peroxidase and used to stain paraffin sections of fixed lung with or without certain pre-treatments. HPA and MPA were observed to react with almost all type II pneumocytes at postnatal day 1. Type II pneumocytes that stained with a sialidase-PNA sequence increased from a few positive cells at postnatal day 5 to many in the adult. It has been reported that the surface coat of type II pneumocytes closely resembles that of Clara cells in its staining with histochemical methods employing cationic dyes or lectins including MPA and PNA. However, staining with HPA, especially after periodic acid oxidation, revealed many type II pneumocytes with strong reactivity but showed only a few Clara cells that were faintly positive. HPA also stained alveolar macrophages. The HPA affinity of macrophages, however, was labile to oxidation with periodic acid or galactose oxidase unlike that of type II pneumocytes. This difference suggests that HPA recognizes more than one type of sugar structure.