Changes In Lectin Binding Patterns Research Articles

Specific lectin binding sites during in vitro capacitation and acrosome reaction in boar spermatozoa

Sperm glycocalyx and plasma membrane undergo outstanding modifications during fertilization. However, it is unclear how in vitro capacitation time and acrosome reaction affect the specific location of boar sperm glycoconjugates. This study aimed to identify lectin binding patterns and to describe the sequential changes during different in vitro capacitation times (1 and 4 h) and acrosome reaction in boar spermatozoa. With Aleuria aurantia agglutinin (AAA), most uncapacitated cells were labelled in the postacrosomal region. Nevertheless, after 1 h of in vitro capacitation and the acrosome reaction, most AAA binding sites were in the acrosomal region. With Concanavalin A (ConA), most sperm were labeled in the postacrosomal region before and after capacitation. After the acrosome reaction induction, this pattern changed to a highly stained acrosomal and postacrosomal regions. Peanut agglutinin (PNA) binding sites were in the acrosomal region in uncapacitated and capacitated sperm. In acrosome reacted sperm after 4h capacitation, the most frequent pattern showed remaining positive labeling in the central area of the head. With Pisum sativum agglutinin (PSA), most uncapacitated cells showed a postacrosomal region staining. Nevertheless, faint stained all over the head and highly acrosomal region labelling was observed in the major part of capacitated and acrosome reacted sperm respectively. With Wheat germ agglutinin (WGA), the most representative pattern in uncapacitated, capacitated and acrosome reacted sperm was labelled in the acrosomal region. Regarding capacitation time, the most significant changes in the most representative pattern were observed in acrosome reacted spermatozoa after 4 h of in vitro capacitation. Highlights Lectins allow detailed descriptions of eight different populations in boar sperm. Changes in lectin binding patterns during capacitation are time dependent. Lectin binding patterns significantly change after 4 h of in vitro capacitation.

Changes in lectin-binding patterns in the kidneys of canines with immune-complex mediated glomerulonephritis.

We surveyed the kidneys of dogs with immune-complex mediated glomerulonephritis (ICGN) by lectin histochemistry using seven lectins—namely WGA, RCA-I, ConA, PNA, SBA, DBA, and UEA-I. Their binding patterns were compared with those from normal dogs. RCA-I signals became weak in the brush borders of the proximal tubules, whereas DBA signals became positive in Bowman’s capsules. Also, varying intensity of the UEA-I signal was noted in the distal tubules, especially in the macula densa. The binding pattern profiles varied among the cases; this diversity in the lectin-binding patterns might be induced as a result of the diverse pathologies seen in canine ICGN.

Molecular imaging using fluorescent lectins permits rapid endoscopic identification of dysplasia in Barrett's esophagus

Barrett's esophagus is an example of a pre-invasive state, for which current endoscopic surveillance methods to detect dysplasia are time consuming and inadequate. The prognosis of cancer arising in Barrett's esophagus is improved by early detection at the stage of mucosal carcinoma or high-grade dysplasia. Molecular imaging methods could revolutionize the detection of dysplasia, provided they permit a wide field of view and highlight abnormalities in real time. We show here that cell-surface glycans are altered in the progression from Barrett's esophagus to adenocarcinoma and lead to specific changes in lectin binding patterns. We chose wheat germ agglutinin as a candidate lectin with clinical potential. The binding of wheat germ agglutinin to human tissue was determined to be specific, and we validated this specific binding by successful endoscopic visualization of high-grade dysplastic lesions, which were not detectable by conventional endoscopy, with a high signal-to-background ratio of over 5.

Gastroesophageal reflux disease leads to major alterations in lectin-binding in the columnar epithelium of the gastroesophageal junction

Objective. Chronic gastritis and esophagitis are associated with changes in glycosylation patterns. Lectins are carbohydrate-binding proteins that are used as sensitive tools in the analysis of glycosylation patterns. The aim was to investigate the binding patterns of lectins UEA-I, DBA, HPA and PNA at the squamocolumnar junction in relation to the existence of gastroesophageal reflux disease (GERD) and Helicobacter pylori (H. pylori) infection. Material and methods. Eighty-eight patients with either dyspeptic or gastroesophageal reflux-related symptoms were included in the study and stratified into four subgroups based on the presence of GERD and H. pylori infection. The binding patterns of lectins were examined immunohistochemically at the squamocolumnar junction, in squamous (SE) and columnar-lined epithelium (CLE). Staining patterns of lectins were semiquantitatively evaluated using an immunohistochemical score; data were analyzed using the non-parametric Mann-Whitney U-test. Results. The presence of GERD led to significant changes in lectin-binding patterns. Lectin-binding was significantly reduced for UEA-I (p<0.0001), DBA (p<0.0001), PNA (p<0.01) and DBA (p<0.05) in CLE and SE of patients with GERD, respectively. H. pylori infection was associated with reduced PNA and DBA binding to the deep glandular mucosa of CLE (p<0.05) and surface SE (p<0.05), respectively. Conclusions. Distinct and complex changes in lectin-staining patterns are most prominent in CLE of patients with GERD. The functional relevance of changes in the glycosylation patterns needs further investigation.

The effect of TNF-α on glycosylation pathways in bovine synoviocytes

Synoviocytes are fibroblastic cells that line joint cavities. These cells synthesize numerous cell-surface and extracellular-matrix glycoproteins that are required for maintenance of the joint. Joint inflammation, such as occurs in arthritis, has been shown to have major effects on synoviocyte proliferation and on the biosynthesis of glycoproteins. The structures of the carbohydrate moieties of glycoproteins, however, and the enzymes involved in their synthesis have not yet been described for synoviocytes. Therefore, to characterize the cell-surface glycoconjugates, synoviocytes were isolated from bovine ankles, and the cells were grown in primary cultures. Lectin-binding assays were used to identify exposed N- and O-glycan carbohydrate determinants on synoviocytes, and specific enzyme assays were used to identify some of the glycosyltransferases involved in the synthesis of the glycan chains. A number of the enzymes that synthesize N- and O-linked oligosaccharides were found to be active in cell-free extracts of synoviocytes, including those that synthesize core-1-based O-glycans and the more complex bi-antennary N-glycans. To understand the molecular events underlying the inflammatory response in the synovium of arthritis patients, we examined the effect of the inflammatory cytokine tumour necrosis factor alpha (TNF-alpha) on synoviocytes and on glycosylation profiles. TNF-alpha treatment, which induces apoptosis in synoviocytes, was accompanied by changes in lectin-binding patterns, indicating alterations in the expression of cell-surface oligosaccharides. Concurrently, changes in specific enzyme activities were observed in treated cells. Two enzymes potentially important to the inflammatory process, core 2 beta6-GlcNAc-transferase and beta4-Gal-transferase, increased after TNF-alpha treatment. This is the first study of glycoprotein biosynthesis in synoviocytes, and it shows that synoviocytes have a characteristic glycosylation phenotype that is altered in the presence of inflammatory cytokines.

Changes in lectin binding patterns in rat esophageal epithelium during development.

Changes in lectin binding patterns during the development of rat esophageal epithelium were examined by light- and electron-microscopy. For the light microscopical observations, 15 kinds of biotinylated lectins were used. Stainings with these lectins were weak before 17 days p.c. (post coitum). On the other hand, positive reactions were progressively observed after 18 days p.c. Among them, ConA and WGA showed a positive reaction on all layers of the epithelium; whereas DSA was positive for the middle and surface layers and UEA-1 was positive for only the middle layer. Electron microscopical observations revealed that UEA-1 showed a strongly positive reaction along the cell membranes of middle-layer cells, and on the apical cell membranes of basal cells. It also showed positive staining on Golgi membranes of the cells in the middle layer. ConA and DSA showed a positive reaction on cell, Golgi, and nuclear membranes. It was confirmed that the differentiation of the three layers (surface, middle and basal layers) of epithelial cells morphologically started to be observed after 17 days p.c. These results suggest that the distribution of glycoproteins in the esophageal epithelium changes in accordance with mucous epithelial cell differentiation.

Changes in Lectin Binding Patterns in Rat Esophageal Epithelium during Development

Changes in Lectin Binding Patterns in Rat Esophageal Epithelium during Development

Changes in Lectin Binding Patterns of Mouse Male Germ Cells (Gonocytes) during Prespermatogenesis.

The distribution of sugar residues in gonocytes of the differentiating mouse testis was examined by light microscopy using 22 different kinds of lectins. Characteristic binding patterns of sWGA, VVA, and LEA in gonocytes were observed during prespermatogenesis. sWGA preferentially bound to the cytoplasm and plasma membrane of gonocytes on 16.5 days post coitus (dpc). Its reaction decreased thereafter and almost disappeared on 1.5 days post partum (dpp), but reaction reappeared on 4.5 dpp and continued until 6.5 dpp. The VVA reaction was recognized in a few gonocytes on 0.5 dpp, and remained strong until 6.5 dpp. LEA reacted strongly in the plasma membrane and cytoplasm of gonocytes from 0.5 dpp to 6.5 dpp. The present study indicates that sWGA, VVA, and LEA are useful markers for gonocytes, and the appearance or disappearance of sWGA and VVA may be related to the differentiation of gonocytes during prespermatogenesis.

Comparison of lectin binding patterns in malformed and normal human embryos and fetuses.

Altered glycosylation in the course of disease detectable by changes in lectin binding patterns has been well established for adult tissues, but only a few authors have described carbohydrate entities during normal human embryonic and fetal development. Whether alterations in carbohydrate patterns occur in human embryonic and fetal tissues, affected by malformations, remains to be investigated. We, therefore, examined human embryos and fetuses at corresponding developmental stages with and without malformations (spina bifida, exencephaly, cleft lip and cleft palate, and dysmelia) with respect to their lectin binding patterns for the lectins RCA I, PNA, WGA, SBA, SNA, Con A, and LTA. Our results demonstrated that during the development of malformations, the affected tissue sites exhibited a different carbohydrate pattern from normally developed specimens. Furthermore, tissues known to be sites of secondary malformation, accompanying the primary defect, although displaying a histologically normal appearance, also showed an altered carbohydrate pattern. This might indicate a possible general alteration in the carbohydrate pattern in the course of development of malformations in man.

Lectin binding pattern of schwann cells and macrophages in 2,5-hexanedione-induced axonal degeneration in rats

The lectin binding pattern of both Schwann cells and macrophages has been studied during axonal degeneration induced in the rat sciatic nerve by chronic administration of 2,5-hexanedione (0.8 ml/kg per day i.p. for 20 days). In particular, the present study aimed to establish a possible relationship between macrophage activation and expression of lectin binding sites. To identify and distinguish between Schwann cells and macrophages, electron microscopy was combined with the lectin staining method. On 2,5-hexanedione injury, a drastic disorganization of both axon and myelin sheath occurred and nerve fibers were replaced by a chain of ovoids. Besides the well-established concept that Schwann cells and macrophages cooperate in the removal of the myelin debris during axonal degeneration, evidence is presented that expression of binding sites to lectins is closely related to macrophage activation. Monocytes occasionally present in control nerves were labelled only by Con A and sialidase-peanut sequence; in 2,5-hexanedione degeneration monocytes, prephagocytes (macrophages with minute bubbles) and phagocytes (macrophages with large bubbles) were labelled also by peanut, wheat germ and BSA I-B4; moreover, phagocytes were labelled by soybean as well, thus showing a clearly differentiation-dependent binding pattern. Since changes in lectin binding pattern may reflect changes in complex carbohydrate structures, the results show that the expression of certain glycoproteins may be closely related to activation of macrophages in response to toxic injuries.

Changes in lectin binding patterns of chick primordial germ cells and Sertoli cells during sexual differentiation.

The distribution and properties of sugar residues in germ and Sertoli cells of differentiating chick gonads were examined by light microscopy using twelve different lectins. Characteristics binding patterns of ConA, RCA-1, BPA, WGA and STA were observed in germ and Sertoli cells during testicular development. BPA preferentially bound to the cytoplasm and plasma membrane of primordial germ cells (PGCs). BPA reaction appeared prior to stage 29, continued until stage 36, and completely disappeared at stage 37. This finding indicates that dynamic changes in glycoconjugates containing N-acetyl-D-galactosamine residues may occur in the cytoplasm and plasma membrane of PGCs. During the formation of testicular cords (stages 36-39), ConA, WGA, STA and RCA-I also showed a positive reaction on the cell surface of differentiating Sertoli cells. Therefore, these glycoconjugates on Sertoli cell surfaces may play an important role in testicular cord formation.

Correspondence to “Changes in Lectin Binding Pattern During Fetal and Postnatal Development of Renal Corpuscles of the Rat Kidney as Revealed by Light and Electron Microscopy” by Imamura H. &lt;i&gt;et al&lt;/i&gt;.

Correspondence to “Changes in Lectin Binding Pattern During Fetal and Postnatal Development of Renal Corpuscles of the Rat Kidney as Revealed by Light and Electron Microscopy” by Imamura H. &lt;i&gt;et al&lt;/i&gt;.

Changes in Lectin Binding Pattern during Fetal and Postnatal Development of Renal Corpuscles of the Rat Kidney as Revealed by Light and Electron Microscopy.

Focussing on glycoconjugates in the renal corpuscle, we examined changes in lectin binding pattern during fetal and postnatal development of rat kidney by light and electron microscopy using biotinylated lectins as a probe. Lectin binding patterns in the renal corpuscle were divided into 3 groups: 1) positive staining throughout all the developmental stages (WGA, ConA, RCA, DSA, PHA-E, PHA-L, and UEA-I); 2) negative reaction throughout all the developmental stages (PNA, SBA, DBA, GS-II, HPA, Lotus, and AAA); 3) a positive reaction that was detected in embryos, but then disappeared during postnatal development (ECA and UEA-II). After neuraminidase digestion, however, ECA and UEA-II strongly stained the glomerular cells and Bowman's capsule throughout all the developmental stages. Electron microscopically, ECA and UEA-II bindings were intensely positive in the plasma membrane of both podocytes and endothelial cells, and in the glomerular basement membrane. Our results suggest that sialic acid is substituted for fucose and/or added to the terminal residues of glycoconjugates that are specifically recognized by ECA and UEA-II in the plasma membrane of podocytes and endothelial cells, and in the glomerular basement membrane during glomerular development.

Changes in lectin binding patterns of Leydig cells during fetal and postnatal development in mice.

Changes in the lectin binding of mouse Leydig cells during fetal and postnatal development were examined by light- and electron-microscopy using eight different biotinylated lectins (ConA, WGA, RCA-I, UEA-I, GS-I, PNA, SBA and GS-II). At the light-microscopic level, ConA, WGA, RCA-I, UEA-I and GS-I showed the same binding pattern in which all five lectins bound to the plasma membrane and cytoplasm of Leydig cells from the 13th day post coitum (p.c.) to the 8th postnatal week. PNA, SBA and GS-II reactions were positive in the plasma membrane and cytoplasm of Leydig cells from the 13th day p.c. to 15th day post partum (p.p.) but disappeared completely by day 20. At the electron-microscopic level, gold particles representing the GS-I or GS-II binding sites were distributed primarily along the cell surface membrane, including that of microvilli, as well as in the cytoplasm. These results indicate that certain glycoconjugates bearing D-galactose, N-acetyl-D-galactosamine, and N-acetyl-D-glucosamine residues are expressed on the cell surface and in the cytoplasm of Leydig cells during the period from the 13th day p.c. to around the 20th day p.p. The results suggest that these glycoconjugates might play some role in modulating hormone-receptor interaction in the Leydig cells before the 20th day. Furthermore, these results may indicate that sugar residues expressed on the cell surface and in the cytoplasm of Leydig cells are different from those in the fetal-neonatal and adult phases.

Changes in Lectin Binding Patterns in Rat Testis and Epididymis in Association with Experimentally-Induced Cryptorchidism.

Changes in Lectin Binding Patterns in Rat Testis and Epididymis in Association with Experimentally-Induced Cryptorchidism.

Changes in Lectin Binding Pattern during Fetal and Postnatal Development of Rabbit Articular Cartilage

Changes in Lectin Binding Pattern during Fetal and Postnatal Development of Rabbit Articular Cartilage

Changes in Lectin-Binding Patterns during Late Fetal Development of the Rat Colon

Lectin-binding and histochemical studies were integrated with a morphological description of colon development in rat fetuses to determine whether changes in glycoprotein sugars could be identified with stages of colon organogenesis. At 16 days gestation the colon consisted of a minute lumen surrounded by 3-5 layers of cuboidal, stratified epithelium, a basement membrane and undifferentiated mesenchyme. As development proceeded, epithelial spaces eventually fused with the main lumen, and fingers of mesenchyme, with a basement membrane and epithelial mantle, formed the walls of crypts lined with simple to stratified columnar cells. Goblet cells and mucin production appeared only on the 20th-21st day of gestation. Mesenchyme differentiation to a circular muscle band, the prospective tunica muscularis, occurred on days 17-18, and vascularization of the lamina propria was first detected on day 19. Wheat germ agglutinin (WGA) lectin bound avidly to sugar residues in the mesenchyme matrix from day 16 but weakened as the tissue differentiated, particularly into smooth muscle. Alcian blue staining of the matrix, also weakening with time, confirmed the sialic acid nature of binding sites for WGA on matrix acid mucopolysaccharides. Under controlled conditions, WGA also detected N-acetylglucosamine-binding sites on brush borders as they developed on the apical surface of primitive enterocytes. Ulex lectin bound to fucose residues of Alcian-blue-positive, PAS-positive mucin from the first appearance of goblet cells. Concanavalin A and glycine max lectins bound only to blood group substances on both nucleated red cells between days 16 and 19 and anucleate red cells from day 19.(ABSTRACT TRUNCATED AT 250 WORDS)

Differentiation-related changes in the distribution of glycoconjugates in rat testis

The distribution of glycoconjugates in differentiating rat testis was investigated by fluorescein labeled lectins during embryogenesis and postnatal development. Double immunofluorescence with rhodamine coupled laminin antibodies was used to delineate testicular cords from the interstitium in embryonic testes. Rat testis was found to be rich in various glycoconjugates, with distinct differentiation-related changes in their distribution. All types of germ cells contained carbohydrate rich compounds in their cytoplasm. Glycosylation in the embryonic testis was different from that in the adult rat. At an early stage of testicular differentiation, the labeling of germ cells and other testicular cells was almost identical. The lectin binding patterns of embryonic germ cells and somatic cells were related to the developmental age of the animal, with a graded disappearance of galactose containing glycoconjugates in embryonal spermatogonia. Spermatogenic cell differentiation was characterized by striking changes in lectin binding patterns of germ cells, particularly in the acrosomes of developing spermatids, in relation to their functional activation and the emergence of adult type of glycosylation during the postnatal maturation of the testis. As the knowledge of regular glycosylation throughout tissue differentiation is of significance for the analysis of aberrant glycosylations occurring in pathologic disorders, our findings suggest the usefulness of lectin histochemistry for the studies on germ cell differentiation.

ラット実験食道癌における組織細胞化学的検討 : レクチン染色を用いた発癌過程の観察および癌の診断,評価について

ラット実験食道癌における組織細胞化学的検討 : レクチン染色を用いた発癌過程の観察および癌の診断,評価について

Changes in lectin binding pattern of gonads of developing mice.

Changes in lectin binding of developing fetal mouse testes and ovaries were examined by light and electron microscopy, with much attention paid particularly to those in carbohydrates of germ cells. Characteristic binding patterns were observed with three lectins (BPA, GS-I, and GS-II) in the germ cells and the somatic cells during the process of testicular and ovarian development. GS-I and BPA, which showed similar binding patterns, preferentially bound to the plasma membrane and small dense bodies (SDB) of germ cells in both testes and ovaries during the 12th to 14th day post coitum (p.c.). In the fetal testes on day 16 p.c., the reaction with both GS-I and BPA completely disappeared. While, in the ovaries, a weak reaction with these lectins was retained as it was in germ cells until the 16th day p.c. The reaction with GS-II was restricted to Sertoli cells in the fetal testes during the 12th to 14th day p.c., and thereafter disappeared on day 16 p.c. The distribution of GS-II binding sites was in agreement with that of the glycogen granules. No positive staining with GS-II was seen in the ovaries throughout their development. These results indicate that certain glycoconjugates containing D-galactose and N-acetyl-D-galactosamine residues are expressed on the cell surface and in the SDB of germ cells during the period of the 12th to 14th day p.c., and that striking changes in function as well as in structure may take place in both germ cells and somatic cells during the 14th to 16th day p.c. in association with testicular and ovarian development.