Phagocytic specificity during sexual development in Dictyostelium discoideum

1986 ◽  
Vol 32 (2) ◽  
pp. 79-82 ◽  
Author(s):  
Keith E. Lewis ◽  
Danton H. O'Day
Keyword(s):  
Dictyostelium Discoideum ◽  
Concanavalin A ◽  
Sexual Development ◽  
Wheat Germ ◽  
Giant Cells ◽  
Inhibitory Effect ◽  
Sexual Cycle ◽  
Type I ◽  
Further Development ◽  
Type Receptor

During the sexual cycle of Dictyostelium discoideum, zygote giant cells develop and serve as foci for further development by chemoattracting and cannibalizing hundreds of local amoebae. Previous work has shown that the phagocytic process bears similarities to and differences from asexual endocytosis. In the present study, sexual phagocytosis in D. discoideum was found to be species and developmental stage specific. It was inhibited selectively by glucose and concanavalin A. Although a partial, inhibitory effect of mannose on phagocytosis was not statistically significant, alpha-methylmannosamine, like alpha-methyl-glucose, significantly restored the phagocytic competence of giant cells treated with concanavalin A. Other sugars (N-acetyl glucosamine, N-acetylgalactosamine, and galactose) and lectins (wheat germ agglutinin, Ulex europus type I, and Ricinis communis agglutinin type I) had no significant effect on sexual phagocytosis. Together these data indicate that a glucose-type receptor is involved in selective uptake of D. discoideum amoebae by giant cells.

Concanavalin A and wheat germ agglutinin binding glycoproteins associated with cell fusion and zygote differentiation in Dictyostelium discoideum: effects of calcium ions and tunicamycin on glycoprotein profiles

1991 ◽  
Vol 69 (4) ◽  
pp. 282-290 ◽  
Author(s):  
Darren D. Browning ◽  
Danton H. O'Day
Keyword(s):  
Dictyostelium Discoideum ◽  
Cell Fusion ◽  
Concanavalin A ◽  
Calcium Ions ◽  
Sexual Development ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Dictyostelium Cell

To determine which glycoproteins may be critical to sexual development in Dictyostelium discoideum, cell samples from different developmental stages were separated by sodium dodecyl sulfate – polyacrylamide gel electrophoresis and blotted to nitrocellulose. Concanavalin A (ConA) and wheat germ agglutinin (WGA) binding proteins were visualized on the blots using an immunochemical procedure employing peroxidase–antiperoxidase. ConA labelled at least 28 proteins, but only one band showed calcium-dependent changes in its expression. WGA bound at least 30 proteins and changes in several bands were observed that did not occur in calcium-deficient controls. Two WGA-binding glycoproteins which migrated at 200 and 166 kilodaltons (kDa), respectively, showed developmental changes associated with the time of cell fusion. One WGA-binding and one ConA-binding glycoprotein migrating at 130 and 126 kDa, respectively, appeared later during sexual development, in association with the phase of zygote differentiation. Several WGA- and ConA-binding glycoproteins decreased during sexual development, but were not affected by the absence of calcium ions. Tunicamycin (1 μg/mL) inhibited cell fusion when added to sexual cultures prior to the appearance of the 166-kDa glycoprotein gp166. The effects of this inhibitor on development support the importance of glycoproteins to cell fusion during sexual development in D. discoideum.Key words: Dictyostelium, cell fusion, glycoprotein, tunicamycin, concanavalin A, wheat germ agglutinin, calcium.

scholarly journals Receptor-mediated gonadotropin action in the ovary. Inhibitory actions of concanavalin A and wheat-germ agglutinin on gonadotropin-stimulated cyclic AMP and progesterone responses in ovarian cells

1981 ◽  
Vol 200 (1) ◽  
pp. 153-159 ◽  
Author(s):  
S Azhar ◽  
K M Menon
Keyword(s):  
Cyclic Amp ◽  
Concanavalin A ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Carbohydrate Chain ◽  
Inhibitory Effect ◽  
Dolichos Biflorus ◽  
Acetylneuraminic Acid ◽  
Ovarian Cells ◽  
Proline Incorporation

Pretreatment of ovarian cells with concanavalin A and wheat-germ agglutinin blocked the gonadotropin-induced cyclic AMP and progesterone responses and this effect was time- and concentration-dependent. Basal production of either cyclic AMP or progesterone, however, was not affected by treatment of cells with lectin. The effect of concanavalin A on gonadotropin-mediated cyclic AMP and progesterone responses was blocked by alpha-methyl D-mannoside and alpha-methyl d-glucoside. Similarly the inhibitory effect of wheat-germ agglutinin was reversed by N-acetyl-D-glucosamine. Pretreatment of ovarian cells with concanavalin A or wheat-germ agglutinin had no effect on protein synthesis in the ovary as monitored by [3H]proline incorporation studies. Concanavalin A and wheat-germ agglutinin did not affect steroid production in response to dibutyryl cyclic AMP and 8-bromo cyclic AMP, indicating that the inhibitory action of lectin was occurring at a step before cyclic AMP formation. Lectins specific for L-fucose, D-galactose and N-acetyl-D-galactosamine, gorse seed agglutinin, peanut agglutinin and Dolichos biflorus agglutinin respectively, did not interfere with gonadotropin-induced cyclic AMP and progesterone responses. The present studies suggest that gonadotropin receptors may be glycoprotein in nature or closely associated with glycoprotein structures with the carbohydrate chain containing N-acetyl-D-glucosamine, mannose and possibly N-acetylneuraminic acid.

Zygote giant cell differentiation in Dictyostelium discoideum: biochemical markers of specific stages of sexual development

1992 ◽  
Vol 70 (10-11) ◽  
pp. 1200-1208 ◽  
Author(s):  
Darren D. Browning ◽  
Keith E. Lewis ◽  
Danton H. O'Day
Keyword(s):  
Alkaline Phosphatase ◽  
Cell Differentiation ◽  
Giant Cell ◽  
Dictyostelium Discoideum ◽  
Cell Fusion ◽  
Sexual Development ◽  
Giant Cells ◽  
Second Phase ◽  
Developmental Phase ◽  
Calcium Dependent

Sexual development in Dictyostelium discoideum has many unique features making it an attractive eukaryotic model system for the study of biomembrane fusion and intercellular communication. The work presented here provides primary biochemical evidence for two distinct phases during early sexual development that appear to be defined by calcium-dependent gamete cell fusion. In addition, we introduce a novel procedure for the enrichment of zygote giant cells and use this method to define certain wheat-germ agglutinin binding glycoproteins which are specifically located in zygote giant cells and others which are markers for surrounding amoebae in the second phase of development. In addition, a G protein which is present in high amounts early in development is unique to giant cells in the second phase, suggesting a role in phagocytosis. Finally, alkaline phosphatase activity was found to mark the first phase of sexual development, suggesting a role in cell fusion. This contrasts with the patterns of α-mannosidase and β-glucosidase activity that increase late in the second developmental phase, where they likely function in endocyte digestion during the cytophagic period. The developmental significance of these findings is discussed.Key words: zygote giant cell differentiation, Ca2+, glycoproteins, GTP-binding proteins, alkaline phosphatase, glycosidase, cell fusion.

Macrocyst development in Dictyostelium discoideum. III. Cell-fusion inducing factor secreted by giant cells

1983 ◽  
Vol 62 (1) ◽  
pp. 237-248
Author(s):  
Y. Saga ◽  
K. Yanagisawa
Keyword(s):  
Dictyostelium Discoideum ◽  
Cell Fusion ◽  
Actinomycin D ◽  
External Medium ◽  
Giant Cells ◽  
Culture Conditions ◽  
Sexual Cycle ◽  
Opposite Mating Type ◽  
Fusion Products ◽  
Type Strains

A factor was discovered that markedly enhances the degree of fusion activity between cells of the opposite mating-type strains, MI1 and NC4, in the sexual cycle of Dictyostelium discoideum. This factor, designated cell-fusion inducing factor (CFIF), was detected initially in supernatants taken from 24 h dark-grown mixed cultures of HM1 and NC4 cells, and subsequently shown to be secreted by giant cells - the fusion products of HM1 and NC4 cells. HM1 cells, cultured in the dark at appropriate temperature, normally acquire fusion-competence specific to NC4 cells. The addition of CFIF to such dark-grown HM1 cultures results in a marked increase in their fusion-competence. In addition, when CFIF is added to light-grown HM1 cultures, in which cells normally do not acquire the ability to fuse with NC4 cells, fusion-competence is induced. The fusion-competence of NC4 cells is unaffected by CFIF, being quite high under the culture conditions used here. Experiments, using actinomycin D, daunomycin and cycloheximide showed that the secretion of CFIF from giant cells requires synthesis of RNA and protein. Possibly, cell fusion triggers production of CFIF, which is rapidly released into the external medium.

Nuclear fusion in multinucleated giant cells during the sexual development of Dictyostelium discoideum

1986 ◽  
Vol 118 (1) ◽  
pp. 95-102 ◽  
Author(s):  
H. Okada ◽  
Y. Hirota ◽  
R. Moriyama ◽  
Y. Saga ◽  
K. Yanagisawa
Keyword(s):  
Dictyostelium Discoideum ◽  
Sexual Development ◽  
Nuclear Fusion ◽  
Giant Cells ◽  
Multinucleated Giant Cells

Effects of some plant lectins on hydrogen peroxide release from macrophages induced with streptococcal preparation OK-432

1980 ◽  
Vol 28 (2) ◽  
pp. 336-343
Author(s):  
H Tomioka ◽  
H Saito
Keyword(s):  
Concanavalin A ◽  
Inhibitory Action ◽  
Wheat Germ ◽  
Specific Binding ◽  
Inhibitory Effect ◽  
Soybean Agglutinin ◽  
Peanut Agglutinin ◽  
Macrophage Phagocytosis ◽  
Receptor Sites ◽  
Wheat Germ Lectin

Concanavalin A and phytohemagglutinin were found to cause marked inhibition of H2O2 release from macrophages induced with killed streptococci (preparation OK-432). The inhibitory effect of these two lectins on the H2O2 release from macrophages was observed with spontaneous and wheat germ lectin-triggered H2O2 release. This suggests that the lectins act directly on the macrophage H2O2-releasing function, per se, but not on the wheat germ lectin-H2O2 release-enhancing process. Concanavalin A exhibited its inhibitory action on macrophage H2O2 release by specific binding to D-mannopyranoside receptor sites on the macrophage cell surface. Galactose-binding lectins, peanut agglutinin, and soybean agglutinin failed to inhibit, but, on the other hand, slightly enhanced macrophage H2O2 release. The effect of these five lectins on the phagocytosis of latex particles by macrophages was tested. Wheat germ lectin, concanavalin A, and phytohemagglutinin significantly depressed the macrophage phagocytosis, whereas peanut agglutinin and soybean agglutinin failed to show any inhibitory action.

scholarly journals Influence of Concanavalin A, wheat germ agglutinin, and soybean agglutinin on the fusion of myoblasts in vitro.

1975 ◽  
Vol 67 (3) ◽  
pp. 826-834 ◽  
Author(s):  
H Den ◽  
D A Malinzak ◽  
H J Keating ◽  
A Rosenberg
Keyword(s):  
Concanavalin A ◽  
Binding Sites ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Inhibitory Effect ◽  
Myoblast Fusion ◽  
Normal Serum ◽  
Specific Cell ◽  
Number Of Binding Sites

Although muscle cell fusion was shown to be an energy-requiring process, release of myoblasts from an EGTA fusion block could be accomplished with Earle's balanced salt solution (containing 1.8 mM Ca++) free of glucose or any other energy-produced metabolite. The effect of concanavalin A, abrin, and the lectins from wheat germ, soybean, and Lens culinaris on myoblast fusion was examined with synchronized myoblast cultures upon release from fusion block. At a concentration of 15 mug/ml, these lectins were found to inhibit the fusion process to the extent of 62%, 41%, 32%, 8%, and 19%, respectively. Concanavalin A inhibition could be prevented by alpha-methyl-D-mannoside. The inhibitory effect of all the lectins except abrin could be reversed by changing to the normal, serum-containing medium. The number of binding sites was 3.4 X 10(7), 6.1 X 10(7), and 1.7 X 10(6), respectively. Although myoblasts were found to have about twice as many binding sites for wheat germ agglutinin as for concanavalin A, concanavalin A was determined to be twice as effective as wheat germ agglutinin as an inhibitor of myoblast fusion. These findngs raise the possibility that specific cell surface glycoproteins may be an important factor in this process.

Pronuclear migration, swelling, and fusion during sexual development in Dictyostelium discoideum

1987 ◽  
Vol 33 (12) ◽  
pp. 1046-1049 ◽  
Author(s):  
David R. McConachie ◽  
Danton H. O'Day
Keyword(s):  
Dictyostelium Discoideum ◽  
Mating Type ◽  
Sexual Development ◽  
Significant Relationship ◽  
Giant Cells ◽  
Mixed Mating ◽  
Binucleate Cells ◽  
Ultrastructural Studies

In mixed mating type cultures (strains NC4 × V12) of Dictyostelium discoideum, gametes fuse to produce binucleate cells which differentiate into zygote giant cells. As pronuclei move together their volumes increase dramatically. Measurements of pronuclear volumes revealed that there is a direct, linear, and statistically significant relationship between pronuclear size and proximity. Juxtaposition of the swollen pronuclei is followed by their fusion. Ultrastructural studies indicate that pronuclear fusion involves intact pronuclear envelopes.

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