DigitalUM :: Browsing by Subject "Lectin"

Browsing by Subject "Lectin"

Now showing 1 - 14 of 14

Open Access
Comparison of ultrastructure and lectin histochemistry on the anterior medial gland of nasal septum in rat and gerbil
(Murcia : F. Hernández, 2010) Chang, Chi-Fen; Chau, Yat-Pang; Lu, Kuo-Shyan
The anterior medial gland (AMG), located in the submucosa of rodent nasal septum, is suggested to provide fluid for humidification of inspired air. Tremendous variation of the environmental air humidity, on which rats and gerbils depend to live, leads us to expect a multiplicity on ultrastructure and various subcellular glycoconjugate distribution within the AMG acinar cells between these two species. Electron microscopy revealed that: (1) The nucleus of AMG acinar cells in rat was irregular-shaped, but that in gerbil was round or elliptical; (2) Secretory granules in rat AMG acinar cells contained homogenous content with various electron density. However, two types of secretory granules in gerbil AMG acinar cells were found: one with lamellated-structure and high electron density, while the others had particulate materials; (3) Myoepithelial cells were present in the acinus of medial and posterior regions in rat AMG, but absent in gerbil; and (4) Nerve terminals were present only in the medial and posterior rat AMG, but in all three regions of the gerbil AMG. Lectin histochemistry demonstrated that: (1) Rat and gerbil AMG acinar cells expressed strong affinity toward Con A and WGA, but neither showed any reactivity toward UEA and PNA; and (2) Varying degrees of reactivity toward different lectins, including DBA, PNA, SBA and EBL, were recognized in rat and gerbil AMG acinar cells. We confirm the species variation on the ultrastructure and lectin histochemistry of AMG in rats and gerbils, and speculate that these variations may be due to the different living environment.
Open Access
Developing follicles of the spotted ray Torpedo marmorata express different glycoside residues in relation to granulosa differentiation and vitelline envelope formation
(Murcia : F. Hernández, 2003) Prisco, M.; Ricchiari, L.; Uliano, R.; Pisacane, A.; Liguoro, A.; Andreuccetti, P.
Lectins constitute a class of proteins/glycoproteins that specifically bind to terminal glycoside residues. The present investigation aimed to identify lectin-binding sites in developing follicles of Torpedo marmorata. Using eleven lectins (WGA, GSIA4, GSI-B4, PSA, UEA-I, PNA, MPA, Con-A, DBA, LCA, BPA, SBA), we demonstrated that the biochemical nature and the distribution of carbohydrate residues significantly change during oogenesis in the granulosa cells and the vitelline envelope. In fact, a progressive appearance of surface glycoproteins bearing terminated ß-GlcNAc O-linked side chains was observed in the granulosa during the differentiation of pyriform-like cells from the small ones via intermediate cells simultaneously with a significant reduction of the D-Gal chains present in their nucleus. Glycoproteins bearing ß- GlcNAc O-linked side chains were first evident on the surface of small cells in contact with the oocyte, then on the intermediate ones, and finally on pyriform-like cells. The distribution pattern of such glycoproteins over the differentiated granulosa cells remained unchanged during the subsequent stages of the oocyte growth so granulosa cells preserved the same sugar distribution pattern. Furthermore, a progressive loss of D-Gal residues was evident in the nucleus of granulosa cells. In fact, staining for D-Gal was intense in the nucleus of small follicle cells and progressively reduced till disappearing in differentiated pyriform-like cells. Conversely, the small follicle cells located under the basal lamina were devoid of ß-GlcNAc residues, and the nuclear content in D-Gal remained unchanged. This finding strongly suggests that surface glycoproteins containing ß-GlcNAc residues, and the nuclear content in D-Gal might be related to the differentiation of pyriform-like cells. The present investigation also demonstrates that the content of the sugar residues of the vitelline envelope (VE) changes during oocyte growth, suggesting that pyriform-like cells may contribute to its formation.
Open Access
Emerging role of tissue lectins as microenvironmental effectors in tumors and wounds
(F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2015) Smetana, Karel Jr.; Szabo, Pavol; Gál, Peter; André, Sabine; Gabius, Hans-Joachim; Kodet, Ondřej; Dvořánková, Barbora
Detailed comparative analysis of at first sight not related process cascades is a means toward this aim: to trace common effector mechanisms and hereby eventually inspire innovative routes for therapeutic management. Following this concept, promotion of tumor progression by stroma, especially cancerassociated fibroblasts and smooth muscle actin-positive myofibroblasts, and beneficial activity of respective cells in wound healing have helped to delineate the involvement of endogenous lectins of the family of galectins. In addition to initiating conversion of fibroblasts to myofibroblasts, galectin-1 instructs the cells to produce a structurally complex extracellular matrix. This bioscaffold is useful for keratinocyte culture, also apparently operative in ameliorating wound healing. These functional aspects encourage to study in detail how lectin-(glycan) counterreceptor display is orchestrated. Such insights are assumed to have potential to contribute to rationally manipulate stem/precursor cells as resource in regenerative medicine.
Open Access
How galectins have become multifunctional proteins
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) García Caballero, Gabriel; Kaltner, Herbert; Kutzner, Tanja J.; Ludwig, Anna-Kristin; Manning, Joachim C.; Schmidt, Sebastian; Sinowatz, Fred; Gabius, Hans-Joachim
Having identified glycans of cellular glycoconjugates as versatile molecular messages, their recognition by sugar receptors (lectins) is a fundamental mechanism within the flow of biological information. This type of molecular interplay is increasingly revealed to be involved in a wide range of (patho)physiological processes. To do so, it is a vital prerequisite that a lectin (and its expression) can develop more than a single skill, that is the general ability to bind glycans. By studying the example of vertebrate galectins as a model, a total of five relevant characteristics is disclosed: i) access to intra- and extracellular sites, ii) fine-tuned gene regulation (with evidence for co-regulation of counterreceptors) including the existence of variants due to alternative splicing or single nucleotide polymorphisms, iii) specificity to distinct glycans from the glycome with different molecular meaning, iv) binding capacity also to peptide motifs at different sites on the protein and v) diversity of modular architecture. They combine to endow these lectins with the capacity to serve as multi-purpose tools. Underscoring the arising broad-scale significance of tissue lectins, their numbers in terms of known families and group members have steadily grown by respective research that therefore unveiled a well-stocked toolbox. The generation of a network of (ga)lectins by evolutionary diversification affords the opportunity for additive/synergistic or antagonistic interplay in situ, an emerging aspect of (ga)lectin functionality. It warrants close scrutiny. The realization of the enormous potential of combinatorial permutations using the five listed features gives further efforts to understand the rules of functional glycomics/lectinomics a clear direction.
Open Access
Human galectin-2: nuclear presence in vitro and its modulation by quiescence/stress factors
(2008) Dvoránková, B.; Smetana, K. Jr.; Lacina, L.; Lensch, M.; Manning, J.C.; André, S.; Gabius, H.J.
Open Access
Improved methodology for the detection and quantification of the acrosome reaction in mouse spermatozoa
(Murcia : F. Hernández, 2009) Lybaert, Pascale; Danguy, A.; Leleux, Fabienne; Meuris, Sylvain; Lebrun, Philippe
This study evaluates the use of two fluorescein-labelled (FITC) plant lectins, Pisum sativum (edible pea) agglutinin (PSA) and Arachis hypogaea (peanut) agglutinin (PNA), in order to determine the most accurate and reliable method to experimentally detect and assess the acrosome reaction in mouse spermatozoa. PNA-FITC labelling was restricted to the acrosome and was not influenced by the fixation procedure; either absolute methanol or paraformaldehyde. In contrast, PSA-FITC not only labelled the acrosome, but also the whole head and the flagellum. This aspect was especially marked after methanol fixation. The cytoplasmic droplet, when present, was also stained by PSA-FITC. Incubation with the calcium ionophore ionomycin induced a concentration and time-dependent increase in the number of acrosome reactions. Compared to spotted preparations, smear samples exhibited a high proportion of spermatozoa with damaged acrosome. In conclusion, PNA-FITC labelling was more accurate than PSA-FITC labelling to detect the acrosome of mouse spermatozoa. The fixation method (methanol vs. paraformaldehyde) had no influence on the staining pattern of PNA-FITC labelling, but spotted preparations are recommended to avoid mechanical damage to the acrosome. Ionophore challenge confirmed the existence of a calcium-dependent acrosome reaction in mouse spermatozoa and validated the use of PNA-FITC to quantify this physiological process. The present study illustrates important methodological considerations which need to be taken into account in order to design a reliable and reproducible protocol for the study of the acrosome reaction.
Open Access
In vivo toxicity of the ribosome- inactivating lectin ebulin f in elderly mice
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2018) Garrosa, Manuel; Jiménez, Pilar; Córdoba Díaz, Damián; García Recio, Verónica; Gayoso, Sara; Rojo, María Ángeles; Gayoso, Manuel J.; Girbés, Tomás
Ebulin f is a ribosome-inactivating protein (RIP) present in green fruits of the dwarf elder (Sambucus ebulus L). Since dwarf elder fruits are used for food and as a medicine, we assessed the study of toxicological effects and safety of ebulin f in elderly mice, comparing these results with those reported in young animals and with other RIPs. Female Swiss mice aged 6 and 12 months of age were intraperitoneally injected with a single dose from 1.4 to 4.5 mg/kg ebulin f. Heart, stomach, intestines, lung, kidney, liver, spleen, pancreas, adrenal gland, uterus, ovary and brain were studied. Histology analysis was carried out by staining with hematoxylin and eosin and Masson’s trichrome observed with a light microscope, or apoptosis detection by TUNEL method observed with a confocal laser microscope. Treated animals injected with the lower dose could recover their weights, but after 14 days half of them died. The higher dose caused a progressive loss of body weight leading to death. In the animals of the experimental groups it was found atrophy of Lieberkühn’s crypts, pneumonia, nephronal degeneration, myocardial atrophy, centrolobular hepatic necrosis, splenic white pulp necrosis foci and increased rate of apoptosis in the intestines and liver, in which apoptoses were mainly located in the vicinity of the lobular central vein. We conclude that ebulin f affects vital organs in elderly mice.
Open Access
Lectin histochemistry of human meningiomas
(Murcia : F. Hernández, 1994) Marafioti, T.; Barresi, G.; Batolo, D.
The lectins Peanut agglutinin (PNA), Canavalia ensiformis (Con A), Ulex europaeusl (UEAl), Dolichos biflorus (DBA), Triticum vulgaris (WGA) were studied in a series of 36 meningiomas (16 meningotheliomatous-including 3 recurrences, 7 transitional, 4 angiomatous, 2 ((hemangiopericytic~3, papillary-including 1 recurrence, 4 anaplastic-including 3 recurrences. PNA binds to all cases of meningotheliomatous, transitional, papillary and anaplastic meningiomas (including recurrent cases) but the staining is more intense in tumor cells of anaplastic and papillary type. A semiquantitative study showed differences of PNAreactivity in the different subtypes of meningiomas. In meningotheliomatous meningiomas PNA-positivity was encountered in numerous neoplastic cells (50%), whereas papillary and anaplastic subtypes expressed strong cytoplasmic staining of few tumor cells (C 5%). Con A shows the same pattern of reactivity described for PNA, but more weakly. Our results suggest that PNA is a marker of differentiation in meningiomas rather than malignant transformation and can have prognostic relevance.
Open Access
Lectin-staining pattern in extratesticular rete testis and ductuli efferentes of prepubertal and adult horses
(Murcia : F. Hernández, 1998) Parillo, F.; Stradaioli, G.; Verini Supplizi, A.; Monaci, M.
This study was undertaken to determine the lectin affinity of the extratesticular rete testis and ductuli efferentes epithelial cells in adult and prepubertal horses. using ten different lectin horseradish peroxidase conjugates: Con-A, LCA, WGA, GSA-11, SBA, PNA, RCA-1, DBA, UEA-1, and LTA. In some cases, treatments with sialidase and KOH preceded the lectin staining. In sexually mature and immature horses the results showed the presence of different kinds of sialoglycoconjugates with the terminal sialic acid linked to D-GalNAc and B-D-Gal residues in the rete testis. In the apical surface and cytoplasm of epithelial cells lining the ductuli efferer~teso f the adult horse, glycoconjugates with a-D-Man andlor a-D-Glc, GlcNAc, D-GalNAc and B-D-Gal residues were evidenced, whereas in the prepubertal horse only the apical surface of the ductuli efferentes epithelial cells resulted reactive toward some lectins. The differences observed in the presence of glycoconjugates between adult and prepubertal horse ductuli efferentes, suggest a hormonal control of the function of these tracts of the post-testicular ducts.
Open Access
Paneth cells are also target of the ribotoxic lectin nigrin b
(2014) Jiménez, Pilar; Gayoso, Manuel José; Garrosa, Manuel; Córdoba-Díaz, Damián; Cabrero, Patricia; Tejero, Jesús; Aracil, Mónica; Girbés, Tomás
Ribosome-inactivating lectins (RILs) are AB type toxins like ricin whose molecular target is the large rRNA of eukaryotic ribosome. Administration of lethal doses of the RIL nigrin b isolated from elderberry (Sambucus nigra L.) bark triggers specific intestinal derangement. The aim of the present research was to explore the early effects of a lethal dose of nigrin b (16 mg/kg body weight) on the small intestine using light and electron microscopy to ascertain intestinal epithelium changes. 6 h after nigrin administration, the small intestine crypts began to show signs of damage with cells appearing at different stages of apoptosis. 16 h after injection crypts appeared more impaired, including the derangement of Paneth cells. The novelty of our results is that the Paneth cells in the small intestine in addition to stem cells are the early cellular targets for nigrin b.
Open Access
REG3A overexpression functions as a negative predictive and prognostic biomarker in rectal cancer patients receiving CCRT
(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2024) Li, Wan Shan; Chen, Tzu Ju; Lee, Sung Wei; Yang, Ching Chieh; Tian, Yu Feng; Kuo, Yu Hsuan; Tsai, Hsin Hwa; Wu, Li Ching; Yeh, Cheng Fa; Shiue, Yow Ling; Chou, Chia Lin; Lai, Hong Yue
Background. Concurrent chemoradiotherapy (CCRT) is suggested before resection surgery in the control of rectal cancer. Unfortunately, treatment outcomes are widely variable and highly patientspecific. Notably, rectal cancer patients with distant metastasis generally have a much lower survival rate. Accordingly, a better understanding of the genetic background of patient cohorts can aid in predicting CCRT efficacy and clinical outcomes for rectal cancer before distant metastasis. Methods. A published transcriptome dataset (GSE35452) (n=46) was utilized to distinguish prospective genes concerning the response to CCRT. We recruited 172 rectal cancer patients, and the samples were collected during surgical resection after CCRT. Immunohistochemical (IHC) staining was performed to evaluate the expression level of regenerating family member 3 alpha (REG3A). Pearson's chi-squared test appraised the relevance of REG3A protein expression to clinicopathological parameters. The Kaplan-Meier method was utilized to generate survival curves, and the log-rank test was performed to compare the survival distributions between two given groups. Results. Employing a transcriptome dataset (GSE35452) and focusing on the inflammatory response (GO: 0006954), we recognized that REG3A is the most significantly upregulated gene among CCRT nonresponders (log2 ratio=1.2472, p=0.0079). Following IHC validation, high immunoexpression of REG3A was considerably linked to advanced post-CCRT tumor status (p<0.001), post-CCRT lymph node metastasis (p=0.042), vascular invasion (p=0.028), and low-grade tumor regression (p=0.009). In the multivariate analysis, high immunoexpression of REG3A was independently correlated with poor disease-specific survival (DSS) (p=0.004) and metastasis-free survival (MeFS) (p=0.045). The results of the bioinformatic analysis also supported the idea that REG3A overexpression is implicated in rectal carcinogenesis. Conclusion. In the current study, we demonstrated that REG3A overexpression is correlated with poor CCRT effectiveness and inferior patient survival in rectal cancer. The predictive and prognostic utility of REG3A expression may direct patient stratification and decisionmaking more accurately for those patients.
Open Access
Reverse lectin histochemistry: Design and application of glycoligands for detection of cell and tissue lectins
(Murcia : F. Hernández, 1993) Gabius, H.J.; Gabius, S.; Zemlyanukhina, T.V.; Bovin, N.V.; Brinck, U.; Danguy, A.; Joshi, S.S.; Kaiser, K.; Schottelius, J.; Sinowatz, F.; Tietze, L.F.; Vidal-Vanaclocha, F.; Zanetta, J.P.
Plant and invertebrate lectins are valuable cyto- and histological tools for the localization of defined carbohydrate determinants. The welldocumented ubiquitous occurrence of sugar receptors encourages functional considerations. Undoubtedly, analysis of the presence of vertebrate lectins in tissues and cells is required to answer the pertinent and tempting question on the physiological relevance of protein (1ectin)-carbohydrate recognition in situ. Carrierimmobilized glycoligands, derived from custom-made chemical synthesis, enable the visualization of respective binding sites. Histochemically inert proteins or synthetic polymers with appropriate functional groups are suitable carrier molecules for essential incorporation of ligand and label. The resulting neoglycoconjugates can track down tissue receptors that are neither impaired by fixation procedures nor blocked by endogenous highaffinity ligands. Lectins, especially the receptors of the tissue under investigation (endogenous lectins), and appropriately tailored immobilized glycoligands or lectin-specific antibodies (when available) are complementary tools to test the attractive hypothesis that diverse, functionally relevant glycobiological processes within or between cells are operative. Concomitant evaluation of both sides of lectin histochemistry, namelylectins as tools and lectins as functionally important molecules in situ, will indubitably render desired progress amenable in our often still fragmentary understanding of the importance of tissue lectin and glycoconjugate expression and its regulation.
Open Access
The induction of gut hyperplasia by phytohaemagglutinin in the diet and limitation of tumour growth
(Murcia : F. Hernández, 1998) Pryme, I.F.; Pusztai, A.; Bardocz, S.; Ewen, S.W.B.
The growth of a transplantable murine non- Hodgkin lymphoma tumour, developing either intraperitoneally as an ascites tumour or subcutaneously as a solid tumour, has been shown to be markedly diminished by including phytohaemagglutinin (PHA), a lectin present in raw kidney bean (I'haseolus vulgaris) in the diet. In NMRl mice fed PHA within the range 0.45-7.0 mg/g diet, tumours which developed during a 10 day period after subcutaneous injection of cells were about 35% of the dry weight of those in lactalbumin-fed (control) animals. The reduced rate of growth occurred in a dose-dependent manner within the range 0.45-3.5 mg/g diet. Based on these observations it has been suggested that a competition between the gut epithelium undergoing hyperplasia and the developing tumour may occur for nutrients from a common body pool, and this may be an important factor with regard to the observed initial low level of tumour growth following the feeding of a PHA-containing diet. Observations which showed that the level of hyperplasia of the small bowel in response to feeding the PHA diets was higher in noninjected mice compared to those which had been injected with tumour cells substantiated the concept of competition between gut and tumour for nutrients etc. required for growth. Experiments with a second murine tumour cell line (a plasmacytoma) in Balblc mice gave similar results indicating that the effect of PHA was not restricted to a single tumour system.
Open Access
Use of lectin-probes for correlative histochemical and biochemical assessments of the glycosylation patterns of secretory proteins, including kallikreins, in salivary glands and saliva
(Murcia : F. Hernández, 1996) Garrett, J.R.; Proctor, G.B.; Zhang, X.S.; Shori, D.K.; Schulte, B.A.
Labelled lectins were used as probes to study the glycosylation and secretion of submandibular glycoproteins not only in sections of fixed glands but also in glandular extracts and in nerve-induced saliva, after electrophoretic separations and immobilization in nitrocellulose membranes. In cats the glycoproteins in sympathetic saliva differed considerably from those in parasympathetic saliva. In sympathetic saliva they were found to originate mainly from striated ducts, to some extent from demilunar cells and to a small extent from acinar cells, whereas in parasympathetic saliva they arose mainly from acinar-cells añd demilunes and only to a small extent from striated ducts. In rat submandibular glands sympathetic stimulation caused extensive depletion of lectin stainable granules from granular tubules. Corresponding strong binding occurred with the same lectins to constituents in saliva that ran between 25 and 35 kD on SDS gel electrophoresis and were shown to contain tissue kallikreins. Their binding patterns suggested that individual kallikreins from the same gland may be glycosylated in different ways. This possibility was tested on five different kallikreins after separation from submandibular extracts by isoelectric focussing. Lectin bindings on slot blot preparations of these kallikreins were tested before and after N-glycosidase F, sialidase or endo-a-Nacetylgalactosaminidase digestions. Results showed that, despite their close genetic and structural similarities, the kallikreins are in fact differently sialylated and fucosylated and the novel finding that some contain Oglycosidically linked side chains as well as the anticipated N-glycosidically linked side chains was revealed. Thus, correlative histochemical and biochemical Offprint requests to: Professor J.R. Garrett, Secretory and Soft Tissue Research Unit, Department of Oral Pathology, The Rayne Institute, KCSMD, 123 Coldharbour Lane, London, SE5 9NU, England assessments of bindings with lectin probes has provided important new information about differences in the glycosylation pattems of individual glycoproteins stored within the same secretory granules.

Browsing by Subject "Lectin"

Results Per Page

Sort Options