Glycoconjugate histochemistry of the rat fundic gland using Griffonia simplicifolia agglutinin-II during the development

Different Forms of TFF2, A Lectin of the Human Gastric Mucus Barrier: In Vitro Binding Studies

Trefoil factor family 2 (TFF2) and the mucin MUC6 are co-secreted from human gastric and duodenal glands. TFF2 binds MUC6 as a lectin and is a constituent of the gastric mucus. Herein, we investigated human gastric extracts by FPLC and identified mainly high- but also low-molecular-mass forms of TFF2. From the high-molecular-mass forms, TFF2 can be completely released by boiling in SDS or by harsh denaturing extraction. The low-molecular-mass form representing monomeric TFF2 can be washed out in part from gastric mucosa specimens with buffer. Overlay assays with radioactively labeled TFF2 revealed binding to the mucin MUC6 and not MUC5AC. This binding is modulated by Ca²⁺ and can be blocked by the lectin GSA-II and the monoclonal antibody HIK1083. TFF2 binding was also inhibited by Me-β-Gal, but not the α anomer. Thus, both the α1,4GlcNAc as well as the juxtaperipheral β-galactoside residues of the characteristic GlcNAcα1→4Galβ1→R moiety of human MUC6 are essential for TFF2 binding. Furthermore, there are major differences in the TFF2 binding characteristics when human is compared with the porcine system. Taken together, TFF2 appears to fulfill an important role in stabilizing the inner insoluble gastric mucus barrier layer, particularly by its binding to the mucin MUC6.

Commercial Porcine Gastric Mucin Preparations, also Used as Artificial Saliva, are a Rich Source for the Lectin TFF2: In Vitro Binding Studies

Mucous gels (mucus) cover internal body surfaces. The secretory mucins MUC5AC and MUC6 and the protective peptide TFF2 are characteristic constituents of gastric mucus; TFF2 is co-secreted with MUC6. Herein, we investigated two commercial mucin preparations by FPLC and proteomics, because they are model systems for studying the rheology of gastric mucins. One preparation is also used as a saliva substitute, for example, after radiation therapy. We show that both preparations contain TFF2 (≈0.6 to 1.1 %, w/w). The majority of TFF2 is strongly bound noncovalently to mucin in a manner that is resistant to boiling in SDS. First overlay assays with ¹²⁵ I-labeled porcine TFF2 revealed that mucin binding is modulated by Ca²⁺ and can be blocked by the lectin GSA-II and the antibody HIK1083, both recognizing the peripheral GlcNAcα1→4Galβ1→R moiety of MUC6. TFF2 binding was also inhibited in the presence of Me-β-Gal but less so by the α anomer. TFF2 may play a role in the oligomerization and secretion of MUC6, the rheology of gastric mucus, and the adherence of gastric microbiota. TFF2 in artificial saliva may be of benefit. TFF2 might also interact with the sugar moiety of various receptors.

Corticosterone activity during early weaning reprograms molecular markers in rat gastric secretory cells

Gastric epithelial cells differentiate throughout the third postnatal week in rats, and become completely functional by weaning time. When suckling is interrupted by early weaning (EW), cell proliferation and differentiation change in the gastric mucosa, and regulatory mechanisms might involve corticosterone activity. Here we used EW and RU486 (glucocorticoid receptor antagonist) to investigate the roles of corticosterone on differentiation of mucous neck (MNC) and zymogenic cells (ZC) in rats, and to evaluate whether effects persisted in young adults. MNC give rise to ZC, and mucin 6, Mist1, pepsinogen a5 and pepsinogen C are produced to characterize these cells. We found that in pups, EW augmented the expression of mucins, Mist1 and pepsinogen C at mRNA and protein levels, and it changed the number of MNC and ZC. Corticosterone regulated pepsinogen C expression, and MNC and ZC distributions. Further, the changes on MNC population and pepsinogen C were maintained until early- adult life. Therefore, by using EW as a model for altered corticosterone activity in rats, we demonstrated that the differentiation of secretory epithelial cells is sensitive to the type of nutrient in the lumen. Moreover, this environmental perception activates corticosterone to change maturation and reprogram cellular functions in adulthood.

Merging carbohydrate chemistry with lectin histochemistry to study inhibition of lectin binding by glycoclusters in the natural tissue context

Recognition of glycans by lectins leads to cell adhesion and growth regulation. The specificity and selectivity of this process are determined by carbohydrate structure (sequence and shape) and topology of its presentation. The synthesis of (neo)glycoconjugates with bi- to oligo-valency (glycoclusters) affords tools to delineate structure-activity relationships by blocking lectin binding to an artificial matrix, often a glycoprotein, or cultured cell lines. The drawback of these assays is that glycan presentation is different from that in tissues. In order to approach the natural context, we here introduce lectin histochemistry on fixed tissue sections to determine the susceptibility of binding of two plant lectins, i.e., GSA-II and WGA, to a series of 10 glycoclusters. Besides valency, this panel covers changes in the anomeric position (α/β) and the atom at the glycosidic linkage (O/S). Flanked by cell and solid-phase assays with human tumor lines and two mucins, respectively, staining (intensity and profile) was analyzed in sections of murine jejunum, stomach and epididymis as a function of glycocluster presence. The marked and differential sensitivity of signal generation to structural aspects of the glycoclusters proves the applicability of this method. This enables comparisons between data sets obtained by using (neo)glycoconjugates, cells and the tissue context as platforms. The special advantage of processing tissue sections is the monitoring of interference with lectin association at sites that are relevant for functionality. Testing glycoclusters in lectin histochemistry will especially be attractive in cases of multi-target recognition (glycans, proteins and lipids) by a tissue lectin.

Loss of anterior gradient 2 (Agr2) expression results in hyperplasia and defective lineage maturation in the murine stomach

Recent studies of epithelial tissues have revealed the presence of tissue-specific stem cells that are able to establish multiple cell lineages within an organ. The stem cells give rise to progenitors that replicate before differentiating into specific cell lineages. The mechanism by which homeostasis is established between proliferating stem or progenitor cells and terminally differentiated cells is unclear. This study demonstrates that Agr2 expression by mucous neck cells in the stomach promotes the differentiation of multiple cell lineages while also inhibiting the proliferation of stem or progenitor cells. When Agr2 expression is absent, gastric mucous neck cells increased in number as does the number of proliferating cells. Agr2 expression loss also resulted in the decline of terminally differentiated cells, which was supplanted by cells that exhibited nuclear SOX9 labeling. Sox9 expression has been associated with progenitor and stem cells. Similar effects of the Agr2 null on cell proliferation in the intestine were also observed. Agr2 consequently serves to maintain the balance between proliferating and differentiated epithelial cells.

Regeneration of gastric mucosa during ulcer healing follows pathways that correspond to the ontogenetic course of rat fundic glands

Gastric ulcers in humans are notoriously chronic and recurring lesions. Although the average individual who undergoes no treatments requires many years for healing, most studies on the healing process of the experimentally induced ulcers have mainly focused on the early stages. Natural history of the ulcer healing has not been completely revealed. We have undertaken long-term investigation up to the 150th day after the cryo-injury to shed light on the natural history of the ulcer healing process compared with developmental changes of postnatal fundic glands. By the 30th day, restitutive gastric glands were mostly seen to cover the ulcer lesions, where well-developed gland-type mucous cells, showing Griffonia simplicifolia agglutinin (GSA)-II labeling, appeared to occupy the basal portion. Most of the bromodeoxyuridine-labeled cells were superimposed on the GSA-II-positive cell zone, forming the proliferative zone. By the 150th day, the restitutive glands were complete, with all epithelial components and topology of the normal fundic glands. The process of the ulcer healing was quite compatible with the developmental changes of the postnatal fundic glands. These results imply that the regeneration of gastric epithelium during the ulcer healing follows pathways linked to the ontogenetic course of the fundic gland.

Glycoconjugates of the gastric mucosa in cold-treated chipmunks

During seasonal hibernation, there is reduced gastrointestinal activity, but relatively little is known of the physiology involved. In the present experimental study, male Korean chipmunks (Tamias sibiricus barberi) were maintained in cold conditions (6 degrees C) for 3, 5 or 9 months to mimic conditions occurring during seasonal hibernation. Changes in the composition of glycoconjugates (Gcs) of the gastric mucosa were determined after cold-treatment. Cold-treated chipmunks, in comparison with warm control animals, revealed a thinner layer of Gcs on the free surface gastric epithelium with reduced depth of their pits. Cold-treated chipmunks showed similar staining patterns and lectin affinity for Gcs as compared with warm control animals. After long-term cold treatment, reduction in the amounts of Gcs were more severe in gastric pit epithelium and glandular mucous cells than in the free surface gastric epithelium. A significant reduction in immunostaining of nitric oxide synthase (NOS) was also observed in chipmunks after long-term cold-treatment. The changes in Gcs and NOS staining patterns may be interpreted in relation with a continued but reduced functioning of the gastric mucosa throughout hibernation. However, the findings in the present experimental model for hibernation, which shows significant changes in Gcs and NOS staining patterns, need to be demonstrated during seasonal hibernation in the wild.

Fluid dynamics of the excretory flow of zymogenic and mucin contents in rat gastric gland processed by high-pressure freezing/freeze substitution

The high-pressure freezing/freeze substitution technique followed by Lowicryl K4M embedding provided an excellent ultrastructure and retention of antigenicity of rat gastric glands as well as the intraluminal fluid contents. By taking this advantage, we histochemically investigated the excretory flow of the zymogenic and mucin contents in rat gastric glandular lumen at the ultrastructural level. The combination of KMnO(4)-UA/Pb staining for zymogenic contents and Griffonia simplicifolia agglutinin-II (GSA-II) labeling for mucous neck cell (MNC) mucin distinguished the exocytosed zymogenic contents from the MNC mucin in the glandular lumen. Interestingly, at the base and neck regions, the zymogenic contents showed a droplet-like appearance, forming a distinct interface with the MNC mucin. At the pit region, the GSA-II labeling demonstrated restricted paths, designated as MNC mucous channels, which flowed into the surface mucous gel layer. It should be noted that the interface between exocytosed zymogenic contents and MNC mucin disappeared, and that the zymogenic contents merged into the MNC mucous channels. At the top pit region, the surface mucous gel layer showed laminated arrays of three types of gastric mucins. On the basis of these ultrastructural findings, we propose a model of the excretory flow in rat gastric gland.

Expression of N-acetylglucosamine residues in developing rat fundic gland cells

The development of rat fundic gland was studied by immunohistochemistry using a recently developed monoclonal antibody, HIK 1083, at both light and electron microscope levels. Antibody HIK 1083 recognized oligosaccharides with a non-reducing terminal alpha-linked N-acetylglucosamine (GlcNAc) residue. In the developing rat fundic gland, cells expressing alpha-GlcNAc residues were discernible from day 19.5 of gestation and continued to exist till adult. The distribution of the alpha-GlcNAc expressing cells was consistent with that described previously for cells reacting to Griffonia simplicifolia lectin (GSA-II) in all developmental stages. These cells were located at the bottom of the fundic gland when they first appeared. With the elongation and maturation of the gland, these cells moved upwards and were finally restricted in the neck region of the gland. Combining previous reports and the present electron microscopical observations, HIK 1083-positive cells in the adult rat fundic gland are mucous neck cells. The interaction between antibody HIK 1083 and GSA-II lectin was investigated. GSA-II prevented the subsequent binding of HIK 1083, while HIK 1083 did not prevent GSA-II binding to mucous neck cells. Our results suggested that alpha-GlcNAc residues exist in rat fundic gland from day 19.5 of gestation and continue to exist till adult. Cells expressing alpha-GlcNAc residues appeared as typical mucous neck cells from postnatal four weeks.

Reappraisal of potassium permanganate oxidation applied to Lowicryl K4M embedded tissues processed by high pressure freezing/freeze substitution, with special reference to differential staining of the zymogen granules of rat gastric chief cells

The high pressure freezing/freeze substitution technique is known to yield a deep vitreous freezing of tissues. Combination of this technique with Lowicryl K4M embedding allows us histochemical studies of dynamic cellular processes with improved structural preservation. The disadvantage of Lowicryl K4M embedding is its poor electron density in electron microscopy. To address this problem, we examined the effects of KMnO4 oxidation applied to Lowicryl K4M embedded rat gastric glands processed by high pressure freezing. The KMnO4 oxidation-uranyl acetate-lead citrate sequence succeeded not only in contrast enhancement of cellular components, but also in differential staining of the zymogen granules of rat gastric chief cells. This technique could be applied to semi-thin sections of Lowicryl K4M embedded rat gastric glands. The KMnO4 oxidation-toluidine blue staining provided sufficient contrast with regard to the zymogen granules. Various experiments used in this study verified that the KMnO4 oxidation plays an essential role in the differential staining of the zymogen granules. Combined use of the KMnO4 oxidation with phospholipase A2-immunostaining demonstrated that gold labeling was localized to the zymogen granules without the loss of immunolabeling. Energy dispersive X-ray microanalysis revealed some manganese depositions on the zymogen granules. It is highly anticipated that the KMnO4 oxidation will become a useful tool for histochemical investigations combined with cryofixation/freeze substitution and low temperature embedding techniques.

Morphological and histochemical variations of mucous and oxynticopeptic cells in the stomach of the seps, Chalcides chalcides

Mucous and oxynticopeptic cells in the gastric mucosa of the seps, Chalcides chalcides (Linnaeus, 1758) were examined by standard histochemical staining methods and by lectin histochemistry. The epithelial mucous cells lining the surface of the stomach and the mucous cells of the fundic glands elaborated mainly neutral glycoproteins with beta(1,4)GlcNAc oligomers, GalNAc glycosidic residues and Gal beta1,3GalNAc terminal sequences. The mucous cells of the fundic glands were stained specifically with the Paradoxical Con A method. The mucosecreting cells of the pyloric glands produced neutral glycoproteins, with beta(1,4)GlcNAc oligomers, GalNAc residues and Gal beta1,3GalNAc terminal sequences. Terminal L-fucose bound to the penultimate GlcNAc residues, and/or difucosylated oligosaccharides were also present. The pyloric glands did not stain with the Paradoxical Con A procedure. The morphology of the oxynticopeptic cells changes from the oral to the aboral region of the fundic mucosa. In the oral fundic tract the oxynticopeptic cells showed cytoplasm filled with zymogen granules, while in the aboral fundic region these cells contained few zymogen granules and showed cytoplasm full of empty vesicles, typical of the acid secreting cells. A secretion gradient of proteolytic enzymes and hydrochloric acid along the fundic mucosa of the seps can be hypothesised.

Histochemical reactivity of normal, metaplastic, and neoplastic tissues to alpha-linked N-acetylglucosamine residue-specific monoclonal antibody HIK1083

Monoclonal antibody (MAb) HIK1083, which is obtained by immunizing mice with a preparation of rat gastric mucins, has been shown to bind specifically to alpha-linked N-acetylglucosamine (alpha-GlcNAc). We investigated the specificity of MAb HIK1083 by immunostaining normal human organs, mucinous metaplasia of human pancreas, adenocarcinomas of human stomach, pancreas, and colon, and normal rat organs. The specificity was investigated by making comparisons with (a) a stain that labels Class III concanavalin A (ConA)-reactive mucin (Class III mucin), i.e., paradoxical ConA (PCS), and (b) staining with horseradish peroxidase (HRP)-conjugated Griffonia simplicifolia agglutinin II (GSA-II). In normal human and rat organs and in mucinous metaplasia of human pancreas, immunostaining with MAb HIK1083 and PCS showed similar specificities for mucins in glandular mucous cells. In adenocarcinoma of stomach and pancreas, GSA-II showed the most widespread positivity, PCS showed the least, and MAb HIK1083 showed a reactivity between those two extremes. Colon adenocarcinomas were labeled only with GSA-II. These results demonstrate that MAb HIK1083 could be a useful screening tool for Class III mucin in normal, metaplastic, and carcinoma tissues, and that the alpha-GlcNAc residue is one of the specific sugar residues found in Class III mucin.

Mucus glycoproteins from pig gastric mucosa: different mucins are produced by the surface epithelium and the glands

An antibody (PGM2B) recognizing a pig gastric-mucin apoprotein reacts with the surface epithelium of pig gastric mucosa. Virtually no reactivity was observed over the mucin-producing cells in the glands, which were recognized by the GlcNAc-selective Griffonia simplicifolia II (GSA-II) lectin. Mucins from the glandular tissue of the cardiac region, corpus and antrum were purified using isopycnic density-gradient centrifugation in CsCl/guanidinium chloride. In the cardiac region, two major mucin populations at 1.5 and 1.4 g/ml were identified. The high-density population reacted preferentially with the PGM2B antibody and resembled mucins from the surface epithelium of this region, whereas the low-density population reacted strongly with the GSA-II lectin and appeared to originate from the glands. In the glandular tissue of corpus, a component with strong GSA-II lectin reactivity, which was distinctly different from the surface mucins from this region, was found at 1.4 g/ml, thus resembling the gland component from the cardiac region. Mucins from antrum glandular tissue contained at least two GSA-II lectin-reactive populations banding at 1.5 and 1.4 g/ml, respectively. Gland mucins from all regions were large oligomeric glycoproteins and heterogeneous with respect to charge properties, as shown by using rate-zonal centrifugation and ion-exchange HPLC, respectively. Gel chromatography of mucin glycopeptides showed that gland mucins from antrum and corpus contained significantly longer glycosylated domains than those from the surface mucosa. Thus, mucins from pig gastric glandular tissue comprise a number of large and oligomeric glycoproteins that differ from those from the surface epithelium in buoyant density, apoprotein structure and carbohydrate substitution.

Peripheral alpha-linked N-acetylglucosamine on the carbohydrate moiety of mucin derived from mammalian gastric gland mucous cells: epitope recognized by a newly characterized monoclonal antibody

To obtain a tool to study the structural characterization and the detection of mucin derived from the gastric gland mucous cells, we developed a monoclonal antibody, designated HIK1083, against mucin purified from rat gastric mucosa. In an ELISA, HIK1083 reacted strongly with the mucin purified from a deep layer of the corpus and antrum but only slightly reacted with that obtained from the surface mucosal layer. The reaction of mucin and HIK1083 was inhibited by the oligosaccharides obtained by the alkaline borohydride reduction of antigenic mucin. Two purified oligosaccharide alditols reacting with the monoclonal antibody obtained from the antigenic mucin had one and two peripheral alpha-linked N-acetylglucosamine residues, respectively, according to the evidence from NMR spectroscopy. Moreover, among the commercially available p-nitrophenyl derivatives of monosaccharides, only p-nitrophenyl-N-acetyl-alpha-D-glucosaminide inhibited the reaction of this monoclonal antibody and the antigenic mucin in a concentration-dependent manner. These results, as well as the immunohistochemical observations, indicate that alpha-linked N-acetylglucosamine residues are specifically attached to the peripheral region of the carbohydrate moiety of the mucin synthesized in and secreted from the gastric-gland-type cells, and indicate that the monoclonal antibody HIK 1083 recognizes this structure.

Ontogeny of sulphated glycoconjugate-producing cells in the rat fundic gland

The ontogeny of sulphated glycoconjugate-producing cells in the rat fundic gland has been studied using high iron diamine (HID), Alcian Blue (AB) at pH 1.0, high iron diamine in combination with Alcian Blue at pH 2.5 (HID-AB), cationic colloidal gold (CCG) at pH 1.0 under light microscopy and CCG (1.0), HID-thiocarbohydrazide (TCH)-silver proteinate (SP)-physical development (PD) under electron microscopy. From day 19.5 of gestation, sulphated glycoconjugate-producing cells were discernible under both light and electron microscopy. The development of such cells can be classified into four stages: (1) a prenatal period from day 19.5 of gestation extending to 0.5 days after birth; (2) 1 day to 2 weeks after birth; (3) 2 to 4 weeks after birth; and (4) the final period from 4 to 8 weeks after birth. Glycoconjugate-producing cells reached maturity by 4 weeks after birth. Our results indicated that glycoconjugate-producing cells were cells along the wall of foveolar lumen, but not those covering the gastric mucosa surface. Our results also suggested that the trans to transmost Golgi apparatus lamellae were the sites of sulphation in the developing rat stomach.

Bromodeoxyuridine-immunohistochemistry on cellular differentiation and migration in the fundic gland of Xenopus laevis during development

Cellular differentiation and migration in the fundic glands of adult and larval Xenopus laevis have been examined using bromodeoxyuridine-immunohistochemistry. In the adult fundic gland, cumulative labeling with bromodeoxyuridine revealed a proliferative cell zone between the surface mucous cells and mucous neck cells, in what is referred to as the neck portion of the gland. The labeling-index of mucous neck cells had rapidly increased by week-5. The labeling-index of oxynticopeptic cells showed a more delayed increase until week-7, coincident with the decrease in the labeling of mucous neck cells. In the immature fundic glands of larvae, the labeled proliferating cells were randomly distributed throughout the developing gastric mucosa. During metamorphosis, the labeling-index of immature epithelial cells was highest at stage 63. Following administration of bromodeoxyuridine at this stage, there was no significant loss of labeled epithelial cells during the metamorphosing period. Furthermore, there was no significant difference in the labeling-indices among the epithelial cells, such as surface mucous cells/generative cells, mucous neck cells, and oxynticopeptic cells, 7 days after administration. Cellular differentiation and migration pathways of epithelial cells in the fundic gland of adult X. laevis and its larvae are discussed.

Alternating laminated array of two types of mucin in the human gastric surface mucous layer

Attempts have been made to develop a procedure for preserving and analysing the surface mucous layer of the human stomach in paraffin sections. Histologically normal gastric mucosae were obtained from 20 surgically removed stomachs. Of the different fixatives tested, Carnoy's solution gave rise to the most satisfactory results. In Haematoxylin-Eosin stained sections, the surface mucous layer appeared as a thick eosinophilic layer coating the gastric mucosal surface and measured 55.4 +/- 2.5 microns in the fundus and 21.8 +/- 1.0 microns in the pylorus respectively. A dual staining method consisting of galactose oxidase-cold thionine Schiff and paradoxical concanavalin A staining was applied to the surface mucous layer in order to reveal the distribution pattern of mucins secreted by two types of mucous cell in the gastric mucosa: surface mucous cells and gland mucous cells. As a result of this staining, an alternating laminated layer was visualized which consisted of the particular two types of mucin. In five cases, the surface mucous layer was examined in unfixed frozen sections. This layer was only partially preserved but revealed the same laminated structure. These results indicated that gland mucous cell mucins contribute to form the surface mucous layer.

Glycoconjugate histochemistry of Xenopus laevis fundic gland with special reference to mucous neck cells during development

Mucous neck cells (MNCs) of the fundic gland are phylogenetically thought to have first appeared in amphibians. We studied the origin and differentiation of MNCs in fundic glands of Xenopus laevis. By means of lectin histochemical methods using Griffonia simplicifolia agglutinin-II (GSA-II), MNCs were detected specifically in fundic glands of adult X. laevis. Mucous granules of MNCs were labeled by GSA-II-colloidal gold (CG) staining. Other cells such as surface mucous cells (SMCs), oxynticopeptic cells (OPCs), and endocrine cells did not react to GSA-II. Ulex europaeus agglutinin-I specifically stained OPCs, but not MNCs and SMCs. During the morphogenetic period of the stomach in metamorphosing larvae, GSA-II reactive cells randomly appeared in various portions of the underdeveloped fundic glands and then rapidly localized in the neck portion. At this time, newly appearing mucous granules of MNC type were labeled by GSA-II-CG. Two types of cells intermediate to MNCs and SMCs and intermediate to MNCs and OPCs were observed in the larval gastric region. Cells intermediate to MNCs and OPCs were also found in adults. In these cells, mucous granules of MNC type were labeled by GSA-II-CG, but mucous granules of SMC type and zymogen-like granules did not react to GSA-II. These observations suggest that GSA-II is a useful marker in studying the differentiation of MNCs and their precursors regardless of species differentiation.

Subcompartment sugar residues of gastric surface mucous cells studied with labeled lectins

We examined the intracellular localization of sugar residues of the rat gastric surface mucous cells in relation to the functional polarity of the cell organellae using preembedding method with several lectins. In the surface mucous cells, the nuclear envelope and rough endoplasmic reticulum (rER) and cis cisternae of the Golgi stacks were intensely stained with Maclura pomifera (MPA), which is specific to alpha-Gal and GalNAc residues. In the Golgi apparatus, one or two cis side cisternae were stained with MPA and Dolichos biflorus (DBA) which is specific to terminal alpha-N-acetylgalactosamine residues, while the intermediate lamellae were intensely labeled with Arachis hypogaea (PNA) which is specific to Gal beta 1,3 GalNAc. Cisternae of the trans Golgi region were also stained with MPA, Ricinus communis I (RCA I) which is specific to beta-Gal and Limax flavus (LFA) which is specific to alpha-NeuAc. Immature mucous granules which are contiguous with the trans Golgi lamellae were weakly stained with RCA I, while LFA stained both immature and mature granules. The differences between each lectin's reactivity in the rough endoplasmic reticulum, in each compartment of the Golgi lamellae and in the secretory granules suggest that there are compositional and structural differences between the glycoconjugates in the respective cell organellae, reflecting the various processes of glycosylation in the gastric surface mucous cells.