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1.
Culture forms of Trypanosoma rangeli could be agglutinated with Canavalia ensiformis (Con A) lectin and, less effectively with Pisum sativum agglutinin (PEA), at a concentration of 200 μg/ml. Ricinus communis agglutinin I (RCA I) agglutinated trypanosomes only if they were not previously washed with physiological Ringer's solution. Three other lectins did not react with the same parasite forms. Direct or indirect lectin-gold labeling techniques were applied to LR-White embedded thin sections of T. rangeli culture forms and to forms in the gut, hemolymph, and salivary glands of Rhodnius prolixus. Under these conditions, Con A was the only lectin out of 9 that bound to the surface of trypanosomes from culture and from the bug hemolymph. Con A did not react with any midgut or salivary gland forms. The preservation of the biological activity of the lectin-gold complexes that did not bind to the parasite surface was confirmed by reactions with structures of the invertebrate host. 相似文献
2.
Bloodstream trypomastigote and culture procyclic (insect midgut) forms of a cloned T. rhodesiense variant (WRATat 1) were tested for agglutination with the lectins concanavalin A (Con A), phytohemagglutinin P (PP), soybean agglutinin (SBA), fucose binding protein (FBP), wheat germ agglutinin (WGA), and castor bean lectin (RCA). Fluorescence-microscopic localization of lectin binding to both formalin-fixed trypomastigotes and red cells was determined with fluorescein isothiocyanate (FITC)-conjugated Con A, SBA, FBP, WGA, RCA, PNA (peanut agglutinin), DBA (Dolichos bifloris), and UEA (Ulex europaeus) lectins. Electron microscopic localization of lectin binding sites on bloodstream trypomastigotes was accomplished by the Con A-horseradish peroxidase-diaminobenzidine (HRP-DAB) technique, and by a Con A-biotin/avidin-ferritin method. Trypomastigotes, isolated by centrifugation or filtration through DEAE-cellulose or thawed after cryopreservation, were agglutinated by the lectins Con A and PP with agglutination strength scored as Con A < PP. No agglutination was observed in control preparations or with the lectins WGA, FBA or SBA. Red cells were agglutinated by all the lectins tested. Formalin-fixed bloodstream trypomastigotes bound FITC-Con A and FITC-RCA but not FITC-WGA, -SBA, -PNA, -UEA or -DBA lectins. All FITC-labeled lectins bound to red cells. Con A receptors, visualized by Con A-HRP-DAB and Con A-biotin/avidin-ferritin techniques, were distributed uniformly on T. rhodesiense bloodstream forms. No lectin receptors were visualized on control preparations. Culture procyclics lacked a cell surface coat and were agglutinated by Con A and WGA but not RCA, SBA, PP and FBP. Procyclics were not agglutinated by lectins in the presence of competing sugar at 0.25 M. The expression of lectin binding cell surface saccharides of T. rhodesiense WRATat 1 is related to the parasite stage. Sugars resembling α-D-mannose are on the surface of bloodstream trypomastigotes and culture procyclics; n-acetyl-D-galactosamine and D-galactose residues are on bloodstream forms; and n-acetyl-D-glucosamine-like sugars are on procyclic stages. 相似文献
3.
Bloodstream trypomastigote and culture procyclic (insect midgut) forms of a cloned T. rhodesiense variant (WRAT at 1) were tested for agglutination with the lectins concanavalin A (Con A), phytohemagglutinin P (PP), soybean agglutinin (SBA), fucose binding protein (FBP), wheat germ agglutinin (WGA), and castor bean lectin (RCA). Fluorescence-microscopic localization of lectin binding to both formalin-fixed trypomastigotes and red cells was determined with fluorescein isothiocyanate (FITC)-conjugated Con A, SBA, FBP, WGA, RCA, PNA (peanut agglutinin), DBA (Dolichos bifloris), and UEA (Ulex europaeus) lectins. Electron microscopic localization of lectin binding sites on bloodstream trypomastigotes was accomplished by the Con A-horseradish peroxidase-diamino-benzidine (HRP-DAB) technique, and by a Con A-biotin/avidin-ferritin method. Trypomastigotes, isolated by centrifugation or filtration through DEAE-cellulose or thawed after cryopreservation, were agglutinated by the lectins Con A and PP with agglutination strength scored as Con A greater than PP. No agglutination was observed in control preparations or with the lectins WGA, FBA or SBA. Red cells were agglutinated by all the lectins tested. Formalin-fixed bloodstream trypomastigotes bound FITC-Con A and FITC-RCA but not FITC-WAG, -SBA, -PNA, -UEA or -DBA lectins. All FITC-labeled lectins bound to red cells. Con A receptors, visualized by Con A-HRP-DAB and Con A-biotin/avidin-ferritin techniques, were distributed uniformly on T. rhodesiense bloodstream forms. No lectin receptors were visualized on control preparations. Culture procyclics lacked a cell surface coat and were agglutinated by Con A and WGA but not RCA, SBA, PP and FBP. Procyclics were not agglutinated by lectins in the presence of competing sugar at 0.25 M.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
4.
PETER R. JACKSON B. M. HONIGBERG STANLEY C. HOLT 《The Journal of eukaryotic microbiology》1978,25(4):471-481
SYNOPSIS. Living, intact bloodstream trypomastigotes and culture procyclic forms of Trypanosoma congolense were tested for agglutination with the lectins concanavalin A (Con A), phytohemagglutinin P (PP), wheat germ agglutinin (WGA), soybean agglutinin (SBA), and fucose binding protein (FBP). Similar experiments were conducted with living bloodstream and culture forms treated with trypsin or dextranase. Parasites were incubated for 30 min at 25 C in various concentrations of each lectin, then examined for agglutination by dark-field microscopy. Control preparations consisted of parasites incubated alone or with 0.5 M of the specific competing sugar, with or without the corresponding lectin. Electron-microscopic localization of lectin binding sites on the surface of intact and dextranase-treated bloodstream and intact culture forms was accomplished with Con A, reacted with horseradish peroxidase (HRP) and then diaminobenzidine (DAB). In addition, FBP and SBA were coupled to HRP, then utilized for the localization of binding saccharides on the surface of blood-stream forms by the DAB technic. Similar studies were conducted with culture procyclics incubated with WGA-, SBA, PP- or FBP-HRP conjugates and then reacted with DAB. Controls were utilized to confirm the sugar specificity of all positive reactions. Intact living bloodstream forms were agglutinated in a concentration-dependent manner with all the lectins tested. Agglutination levels were scored as Con A > FBP > WGA = PP = SBA. Sugars resembling α-D-mannose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, and α-L-fucose are evidently present on the surface of the parasites. No agglutination was noted in any control preparations. Identical lectin-induced agglutinations were obtained with trypsin- or dextranase-treated bloodstream forms. Trypsin disrupted but did not entirely remove the surface coat of bloodstream forms, while dextranase did not alter the ultrastructure of the parasites. Con A-, SBA- and FBP-binding saccharides were distributed uniformly on the surface coat of intact bloodstream forms; a similar distribution of Con A receptors was noted also on the surface of dextranase-treated cells. No lectin-binding saccharides were visualized by electron microscopy on any control preparations. Intact, trypsin- or dextranasetreated, procyclics were agglutinated in a concentration-dependent fashion by Con A and WGA, but not by the other lectins tested. Control preparations did not agglutinate and the enzymes did not affect the ultrastructure of the parasites. Con A- and WGA-specifically binding saccharides were uniformly distributed on intact procyclics and control preparations were lectin-negative. Thus, T. congolense procyclics retained surface saccharides resembling α-D-mannose and N-acetyl-D-glucosamine but lost sugars resembling N-acetyl-D-galactosamine (or D-galactose) and α-L-fucose. The failure of dextranase to remove the lectin-binding saccharides from the surface of bloodstream and procyclic forms suggests that α-1,6-glucan bonds do not link these carbohydrates. The results are contrasted with lectin research on other trypanosome species and discussed with relation to the biology of T. congolense. 相似文献
5.
Studies of membrane glycoconjugates of Taenia taeniaeformis were initiated by assays of the lectin binding characteristics of 35-day-old cysticerci. Parasites fixed in glutaraldehyde were incubated with one of the following FITC-labelled lectins: Concanavalin A (Con A), Lens culinaris agglutinin (LCA), Ricinus communis agglutinin (RCA), peanut agglutinin (PNA), fucose binding protein (FBP) and wheat germ agglutinin (WGA) and either their specific or a nonspecific sugar. Ultraviolet microscopy revealed that only Con A and LCA bound in large amounts to the surface of cysticerci. This binding was partly inhibited by the specific sugar, but the nonspecific sugar had little effect. The lectin not removed by either of the sugars may have been bound nonspecifically to the charged glycocalyx. Lectins were primarily bound on the anterior third of the parasite around the scolex invagination. Kinetic studies of lectin interactions were carried out with LCA and RCA by spectrophotofluorometric analysis of the amount bound specifically or nonspecifically over a range of lectin concentrations. Lens culinaris lectin binding was found to be specific and involve 2 receptors which showed large differences in their affinity for lectin and prevalence on the surface. Ricinus communis lectin did not bind specifically but nonspecific interactions were observed. Adherence of small numbers of host cells was shown to have no measurable effect on the lectin binding characteristics. The results suggest that the major surface carbohydrates exposed are D-mannose and/or D-glucose residues with the other sugar groups poorly represented. This relatively homogeneous surface may have implications for the antigenicity of the parasite in its host. 相似文献
6.
Enrique J. del Pino Marcelo O. Cabada María C. Fonio 《Molecular reproduction and development》1981,4(2):97-104
Various plant lecins were employed in cell agglutination experiments to ascertain the presence of specific saccharides in the surface of B arenarum and L chaquensis spermatozoa. B arenarum spermatozoa were specifically agglutinated with Concanavalin A (Con A), phytohemagglutinin P (PHA-P), and wheat germ agglutinin (WGA), but not with soybean agglutinin (SBA). In contrast, L chaquensis spermatozoa were strongly agglutinated by SBA, WGA, and PHA-P. L chaquensis spermatozoa did not agglutinate with Con A even at high concentrations. Lectinmediated sperm agglutination was inhibited in the presence of specific lectinbinding sugars. Spermatozoa from both species were agglutinated randomly with all lectins suggesting a uniform distribution in the sperm surface of the lectinbinding saccharide ligands. B arenarum sperm agglutination induced by Con A is sensitive to temperature. B arenarum spermatozoa are more agglutinable at 24°C than at 4°C. These results suggest that lectin-binding site mobility is necessary for sperm agglutination. 相似文献
7.
Expression of lectin receptors on the surface of granulocyte-macrophage progenitor cells (CFU-gm) 总被引:1,自引:0,他引:1
It has been emphasized that specific bindings between membrane glycoproteins and membrane lectin-like substances are important in cell-to-cell interactions. We explored the surface of granulocyte-macrophage precursor cells (CFU-gm) by the differential agglutination technique. Enrichment of CFU-gm in the agglutinated fraction, containing the cells which have lectin receptors, from marrow treated with soybean agglutinin (SBA), peanut agglutinin (PNA) and concanavalin A (Con A), suggests the presence of reactive galactosyl and mannosyl residues on the surface of CFU-gm. On the other hand, wheat germ agglutinin (WGA), phytohemagglutinin (PHA) and ulex europaeus agglutinin (UEA), which bind to reactive N-acetylglucosamine, N-acetylgalactosamine and fucose, respectively, did not specifically agglutinate CFU-gm. Thus, reactive groups containing galactosyl and mannosyl structures on the surface of CFU-gm may possibly play a role in the process of cell-to-cell interactions between CFU-gm and marrow stromal cells. 相似文献
8.
The ability of seven lectins to bind to newt epidermal cells and influence their motility was examined. Of the seven fluoresceinated lectins applied to frozen sections containing intact newt skin and migrating epidermis (wound epithelium), only Con A (concanavalin A), WGA (wheat germ agglutinin), and PNA (peanut agglutinin) produced detectable epidermal fluorescence. Con A and WGA each heavily labeled all layers of intact epidermis, but PNA bound only to the more superficial layers. In contrast to a single population of labeled cells in migrating epidermal sheets after treatment with Con A, there were both labeled and unlabeled cells after exposure to either WGA or PNA. The wound bed was labeled by both Con A and WGA, but not by PNA. DBA (Dolichos bifloris agglutinin), RCA I (Ricinus communis agglutinin), and UEA (Ulex europaeus agglutinin), did not produce significant fluorescence with either migrating or intact epidermis. In general, inhibitory effects on epidermal motility correlated with the binding studies. Thus, Con A, WGA, and PNA, the lectins which clearly bound to the epidermis, all produced a concentration-dependent depression in the rate of epidermal wound closure. RCA was somewhat paradoxical in that it was moderately inhibitory despite showing essentially no binding. The effects of SBA and UEA were equivocal. DBA had no effect. These results indicate that the inhibition of motility produced by Con A that we have described previously is not peculiar to this mannose-binding lectin, but is shared by at least one lectin with an affinity for D-GlcNAc (WGA), and one with an affinity for B-D-Gal(1-3)-D-GalNAc (PNA).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
9.
Modulation of endothelial cell surface glycoconjugate expression by organ-derived biomatrices 总被引:5,自引:0,他引:5
Hellmut G. Augustin-Voss Robert C. Johnson Bendicht U. Pauli 《Experimental cell research》1991,192(2):346-351
Cell surface molecules play an important role in cellular communication, migration, and adherence. Here, we show the effect of organ-derived biomatrices on endothelial cell surface glycosylation. Five different lectins (with and without neuraminidase treatment) have been used as probes in an enzyme-linked lectin assay to quantitatively detect glycoconjugates on endothelial cells (BAEC) grown on tissue culture plastic or biomatrices isolated from bovine lung, liver, and kidney. BAEC generally exhibit strong binding of concanavalin A (Con A), Ricinus communis agglutinin I (RCA-I), wheat germ agglutinin (WGA), and soybean agglutinin, and peanut agglutinin after neuraminidase pretreatment of cells (Neu-SBA and Neu-PNA), while SBA and PNA consistently bind weakly to BAEC. BAEC grown on organ-derived biomatrices exhibit significantly altered binding intensities of Con A, RCA-I, WGA, and Neu-PNA: BAEC cultured on lung- or kidney-derived biomatrices express significantly stronger binding affinities for Con A and RCA-I than BAEC grown on liver-derived biomatrix or tissue culture plastic. In contrast, BAEC binding of WGA and PNA (after treatment of cells with neuraminidase) is significantly reduced when BAEC are grown on liver- or kidney-derived biomatrix. Quantitative lectin immunogold electron microscopy reveals consistently stronger lectin binding over nuclear regions compared to junctional regions between neighboring cells. These results indicate that extracellular matrix components regulate endothelial cell surface glycoconjugate expression, which determines cellular functions, e.g., preferential adhesion of lymphocytes or metastatic tumor cells. 相似文献
10.
The stage-specific expression of surface antigens by Trypanosoma lewisi was investigated using monoclonal antibodies directed against this parasite. Hybridomas secreting monoclonal antibodies were produced by the fusion of SP2/0-Ag 14 mouse plasmacytomas with spleen cells from rats infected previously with the Taliaferro strain of T. lewisi. Additivity enzyme-linked immunosorbent assays and indirect immunofluorescent antibody tests indicated the determinant recognized by monoclonal antibody TL40.3 (IgM) was different from those recognized by monoclonal antibodies TL40.1 (IgA), TL40.2 (IgM), and TL40.6 (IgG2 alpha). Monoclonal antibody TL40.3 agglutinated trypanosomes collected 3 days after parasite inoculation while monoclonal antibodies TL40.1, TL40.2, and TL40.6 agglutinated trypanosomes collected 6 days after inoculation. Since agglutinin titers against trypanosomes from irradiated (700 rad from a 60Co source) and nonirradiated rats were similar, expression of the antigens recognized by the monoclonal antibodies appeared to be independent of the immunological state of the host and the morphology of the parasite. The reproduction of T. lewisi in in vitro trypanostatic assays was inhibited only when the monoclonal antibodies were present in concentrations greater than or equal to those needed to agglutinate the trypanosomes. Monoclonal antibodies TL40.1 and TL40.3, but not TL40.2 and TL40.6, agglutinated erythrocytes collected later in the infection from irradiated, infected rats. None of the monoclonal antibodies agglutinated erythrocytes from nonirradiated, infected rats, from irradiated, noninfected rats or from nonirradiated, noninfected rats. This suggests that immunocompetent rats may make blocking antibodies against the exoantigens recognized by monoclonal antibodies TL40.1 and TL40.3. 相似文献
11.
Fuchs N Sonda K Bütikofer P Hemphill A 《International journal for parasitology》1999,29(10):1597-1611
The surface-associated molecules of the invasive stages of apicomplexan parasites such as Neospora caninum and Toxoplasma gondii are most likely crucially involved in mediating the interaction between the parasite and its host cell. In N. caninum, several antigens have recently been identified which could participate in host cell adhesion and/or invasion. These are antigens which are either constitutively expressed on the outer plasma membrane, or antigens which are only transiently localised on the surface as they are expulsed from the secretory vesicles either prior, or after host cell invasion. Some of these proteins have been characterised at the molecular level, and it has been shown that they are, with respect to protein sequences, closely related to homologous counterparts in T. gondii. Nevertheless, there is only a low degree of cross-antigenicity between the two species. In microbial interactions it has been shown that carbohydrates could also play a crucial role in host cell recognition and immunological host parasite interactions. In this study we present data which strongly suggest that the surface of N. caninum tachyzoites is glycosylated. In SDS-PAGE, glycoproteins comigrated largely with glycosylphosphatidylinositol-anchored proteins which were identified using in vivo [3H]ethanolamine labelling followed by autoradiography. The lectin Con A reacted strongly with the surface of these parasites, binding of which is indicative for the presence of N-glycans. Additional surface binding was observed, although only in a subpopulation of all tachyzoites, for wheat germ agglutinin and Jacalin. Intracellular binding sites for Con A were mainly associated with the parasite dense granules. By lectin labelling of Western blots of N. caninum protein extracts, glycoproteins were identified which reacted specifically with the lectins Con A, wheat germ agglutinin, Jacalin and soy bean agglutinin. 相似文献
12.
When plated at high cell density in a microwell culture system, freshly dissociated embryonic mouse cerebellar cells assemble into reproducible, 3-dimensional patterns. The addition of the dimeric lectin Succinyl Concanavalin A blocks reversibly the formation of the microwell pattern, suggesting that cell surface carbohydrates affect the reassociation behavior of embryonic mouse cerebellar cells. Agglutination studes of dissociated cell populations harvested from different regions of the embryonic brain reveal that different lectins agglutinate cell populations from different embryonic brain regions. Cells from E13 cerebellum are agglutinated with Concanavalin A, wheat germ agglutinin, Ricinus communis agglutinin, mol wt 60,000, Ricinus communis agglutinin, mol wt 120,000, and Lens culinaris, but not by soybean agglutinin or a fucose-binding protein. Cells from the midbrain are agglutinated only with Concanavalin A, Ricinus communis agglutinin, mol wt 60,000 and Ricinus communis agglutinin, mol wt 120,000; those from the cerebral cortex are agglutinated only with Lens culinaris; and those from the medulla are agglutinated only with Ricinus communis agglutinin, mol wt 60,000, and Ricinus communis agglutinin, mol wt 120,000. In addition, agglutination of cerebellar cells with Concanavalin A, wheat germ agglutinin, and Ricinus communis agglutinin is diminished over the course of development from embryonic day 13 to postnatal day 7. These studies suggest regional differences in the cell surfaces of the developling brain that are further modulated during the differentiation of the tissues. On a poly(D-lysine) treated substrate in microwell cultures, cell migration is unique to the cerebellum of the 4 brain regions studied. Surfaces treated with carbohydrate-derivatized poly(D-lysine) are currently being tested for their efficacy as substrates for differential cell migration. 相似文献
13.
H. Kreipe H. J. Radzun U. Schumacher M. R. Parwaresch 《Histochemistry and cell biology》1986,86(2):201-206
Summary In the present study unstimulated and stimulated human blood monocytes, untreated and phorbol ester treated U-937 cells, as well as human peritoneal and alveolar macrophages were studied with respect to their surface membrane properties. Binding of different lectins and electrophoretic patterns of tritium labeled surface glycoproteins were compared. The analysis of surface glycoproteins could be interpreted as evidence for a common origin of the analysed cell populations. Furthermore, banding patterns of glycoproteins might be useful to define certain activation states within monocyte/macrophage differentiation. In contrast, lectin binding pattern did not clearly discriminate macrophage subpopulations.Abbreviations AM
alveolar macrophage
- BM
blood monocyte
- PM
peritoneal macrophage
- PBS
phosphate buffered saline
- IPA
12-O-tetradecanoylphorbol-13-acetate
- Con A
Concanavalin A
- HPA
Helix pomatia agglutinin
- LPA
Limulus polyphemus agglutinin
- PHA
Phaseolus vulgaris agglutinin
- SBA
Soy bean agglutinin
- UEA I
Ulex europaeus agglutinin I
- WGA
Wheat-germ agglutinin 相似文献
14.
Pneumocystis carinii obtained from infected rat lung homogenates was incubated with fluorescein isothiocyanate-conjugated lectins, counterstained with the nuclear stain, propidium iodide (PI), and analyzed by dual parameter histograms for lectin-associated green and PI-associated red fluorescence using a fluorescence-activated cell sorter. The presence of glucose/mannose moieties was evidenced by the binding of all organisms to concanavalin A and Wisteria floribunda. From the lectin group specific for N-acetyl-D-glucosamine, P. carinii reacted strongly with wheat germ agglutinin and less intensely with Solanum tuberosum. Reaction with lectins specific for N-acetyl-D-galactosamine/galactose was variable, probably reflecting the secondary binding affinities of the lectins used. Soybean agglutinin, Bauhinia purpurea agglutinin, and Maclura pomifera agglutinin reacted moderately, whereas Dolichos biflorus agglutinin, and Griffonia simplicifolia I reacted less avidly. The organisms reacted partially with Ulex europaeus agglutinin, a lectin specific for fucose, and did not react well with Arachis hypogaea, Viscum album agglutinin, and Griffonia simplicifolia I beta 4, lectins specific for galactose. A very weak fluorescent signal was detected with Limax flavus agglutinin, suggesting little or no sialic acid was present. All lectin-binding reactions were confirmed for specificity by inhibition with the relevant carbohydrates. Flow cytometric analysis of lung-derived Pneumocystis organisms stained with fluorescent surface and nuclear dyes provides a rapid method for characterization of large parasite populations. 相似文献
15.
The infective stages of Leishmania braziliensis, amastigotes and promastigotes subcultured a limited number of times, were agglutinated by Ricinus communis agglutinin and Concanavalin A. These results suggest that terminal ligands similar or identical with alpha-D mannose, alpha-D glucose (specific receptors for Con A), and alpha-D galactose (specific receptor for RCA) are present in the surface membrane of L. braziliensis. Noninfective promastigotes from the same stock, but subcultured approximately 500 times, were not agglutinated by RCA suggesting either the absence of the alpha-D galactose groups in the surface membrane or their presence in a very reduced number. Agglutination with soybean agglutinin, wheat germ agglutinin, or phytohemagglutinin P was not observed in any of the L. braziliensis forms tested. The difference in polysaccharide residues on the surface membrane of L. braziliensis may be related to the different pathogenic properties of the cell. 相似文献
16.
Virulent and avirulent strains of Aerococcus viridans (var.) homari were used to extend previous studies to determine and confirm differences between the 2 types. Virulent strains possessed polysaccharide capsules and were not agglutinated by lobster hemolymph serum; avirulent strains did not have capsules, were agglutinated by the lobster hemolymph serum, and most did not grow well in lobster hemolymph serum. Growth of the avirulent strains in sterile lobster hemolymph serum induced the production of capsules (which reached a maximum after 5 to 7 d incubation), eliminated susceptibility of the strains to the lobster serum agglutinin, and restored their virulence against lobsters. The factor(s) in lobster hemolymph serum inducing the long-lasting phenotypic response of virulence was (were) heat labile. 相似文献
17.
Baccan GC Falleiros AM Cavazzana M Jankevicius JV Attias M De Souza W Itow Jankevicius S 《Journal of invertebrate pathology》2001,77(3):158-164
The defense response of Veneza zonata (Hemiptera: Coreidae) against three different trypanosomatid infections was assessed: (1) strain 714TD, a Leptomonas which has V. zonata as vector of a plant trypanosomatid, (2) strain 563TD, a Leptomonas isolated from the digestive tract of Euchistus heros (Hemiptera: Pentatomidae), and (3) Leishmania (L.) amazonensis, a human parasite that cannot infect V. zonata. Experiments with V. zonata hemolymph showed agglutination only of L. (L.) amazonensis culture forms and hemocytic recognition was more intense with this strain. L. (L.) amazonensis also activated the prophenoloxidase system, whereas strains 714TD and 563TD did not activate this system but rather seemed to inhibit phenoloxidase activity. No flagellates were seen in the digestive tract, hemolymph, or salivary glands in insects infected with L. (L.) amazonensis. The digestive tract, the hemolymph, and the salivary glands of insects fed on tomatoes inoculated with 714TD are sequentially invaded by the flagellate, which is inoculated in plants together with saliva. Insects fed on tomatoes inoculated with 563TD exhibited culture forms in the digestive tract (6 days after) and hemocoel (three additional days); however, they died 12 to 14 days after exposure. The salivary glands in insects inoculated in the hemocoel with 714TD strain are rapidly invaded, whereas those with 563TD culture forms died approximately 24 h after infection. Bacterial proliferation in the hemocoel and hemocyte surface blebbing were seen in insects infected only with 563TD strain as the probable pathogenic mechanism of insect death. 相似文献
18.
Ultrastructural localization of lectin receptors on the luminal and abluminal aspects of brain micro-blood vessels 总被引:4,自引:0,他引:4
A W Vorbrodt D H Dobrogowska A S Lossinsky H M Wisniewski 《The journal of histochemistry and cytochemistry》1986,34(2):251-261
Lectin- or glycoprotein-colloidal gold complexes were used for detection of specific monosaccharide residues in mouse brain micro-blood vessels (MBVs). The lectins tested recognize the following residues: beta-D-galactosyl (Ricinus communis agglutinin-120, RCA-1), alpha-N-acetylgalactosaminyl (Helix pomatia agglutinin, HPA), alpha-D-mannosyl and alpha-D-glucosyl (Concanavalin A, Con A), sialoglycoconjugates (Limax flavus agglutinin, LFA), N-acetylglucosaminyl and sialyl (wheat germ agglutinin, WGA), and alpha-L-fucosyl (Ulex europeus agglutinin, UEA-1). Use of these lectin-gold complexes and ultrathin sections of Lowicryl K4M-embedded tissue makes it possible to gain insights into localization of lectin receptors in the entire cross-section of MBV walls. Receptors for all lectins, except UEA-1, were found on both luminal and abluminal fronts of the endothelial cells (ECs). Differential labeling of luminal and abluminal fronts of ECs with some lectins (Con A, HPL) is considered to reflect the polarity of the endothelium. Some differences noted in the distribution of lectin receptors in the wall of representatives of three types of MBVs (capillaries, arterioles, and venules) are thought to be associated with different functions performed by the above-mentioned segments of the microvasculature in maintenance of the blood-brain barrier. 相似文献
19.
为进一步探讨从生殖细胞到精子的发育过程中细胞质膜表面凝集素受体的可能变化,及其与两类对凝集素标记有不同结果的精子的关系,用异硫氰酸荧光素标记的伴刀豆凝集素(Con A)、麦芽凝集素(WGA)和大豆凝集素(SBA)对蚕豆(Vicia faba L.)、鸢尾(Iris tectorium Maxim.)和朱顶红(Hippeastrum vittatum Herb.)的生殖细胞质膜表面的凝集素受体进行标记。结果显示:在不同植物中均有部分生殖细胞不能被凝集素探针标记,且在保持尾状形态的生殖细胞的表面发现有凝集素受体的极性分布。这可能是导致部分精子表面不能被同种凝集素标记的重要原因。此外,同一种凝集素受体在不同物种的生殖细胞上分布不一致,不同的凝集素受体在同一种植物的生殖细胞上的分布模式亦有不同。在蚕豆和鸢尾的生殖细胞表面均有这三种凝集素的受体。在朱顶红生殖细胞的表面有前两种凝集素的受体,分布比较均一,但是没有大豆凝集素的受体。此外,在具尾生殖细胞表面发现有凝集素受体极性分布的现象,为探讨精细胞功能及其表面糖蛋白分布的可能差异提供了重要启示。 相似文献
20.
为进一步探讨从生殖细胞到精子的发育过程中细胞质膜表面凝集素受体的可能变化,及其与两类对凝集素标记有不同结果的精子的关系,用异硫氰酸荧光素标记的伴刀豆凝集素(Con A)、麦芽凝集素(WGA)和大豆凝集素(SBA)对蚕豆(Vicia faba L.)、鸢尾(Iris tectorium Maxim.)和朱顶红(Hippeastrum vittatum Herb.)的生殖细胞质膜表面的凝集素受体进行标记.结果显示:在不同植物中均有部分生殖细胞不能被凝集素探针标记,且在保持尾状形态的生殖细胞的表面发现有凝集素受体的极性分布.这可能是导致部分精子表面不能被同种凝集素标记的重要原因.此外,同一种凝集素受体在不同物种的生殖细胞上分布不一致,不同的凝集素受体在同一种植物的生殖细胞上的分布模式亦有不同.在蚕豆和鸢尾的生殖细胞表面均有这三种凝集素的受体.在朱顶红生殖细胞的表面有前两种凝集素的受体,分布比较均一,但是没有大豆凝集素的受体.此外,在具尾生殖细胞表面发现有凝集素受体极性分布的现象,为探讨精细胞功能及其表面糖蛋白分布的可能差异提供了重要启示. 相似文献