Specific binding of acrosome-reaction-inducing substance to the head of starfish spermatozoa

Zygote ◽  
1993 ◽  
Vol 1 (2) ◽  
pp. 121-127 ◽  
Author(s):  
Akira Ushiyama ◽  
Takeo Araki ◽  
Kazuyoshi Chiba ◽  
Motonori Hoshi
Keyword(s):  
Acrosome Reaction ◽  
Specific Binding ◽  
Molecular Size ◽  
Polystyrene Latex ◽  
Anterior Region ◽  
Head Region ◽  
Signal Molecule ◽  
Jelly Coat ◽  
Plot Analysis ◽  
Species Specific

In the starfish, spermatozoa undergo the acrosome reaction upon encountering the jelly coat of eggs. A highly sulphated glycoprotein in the jelly coat is called acrosome-reaction-inducing substance (ARIS) because it is the key signal molecule to trigger the acrosome reaction. The activity of ARIS is mainly attributed to its sulphate and saccharide residues. The extremely large molecular size and speciesspecific action of ARIS suggest the presence of a specific ARIS receptor on the sperm surface, but no experimental evidence for the receptor has been presented. We therefore measured specific binding of ARIS and its pronase digest (P-ARIS), which retains the full activity of ARIS, to homologous spermatozoa by using fluorescien-isothiocyanate-labelled ARIS and125 I-labelled P-ARIS, respectively. The spermatozoa had the ability to bind ARIS, as well as P-ARIS, specifically. The binding was species-specific, and mostly localised to the head region of spermatozoa. Scatchard plot analysis indicated the presence of one class of ARIS receptor on the surface of acrosome-intact speramatozoa. Furthermore, the specific binding of P-ARIS to the anterior region of sperm heads was microscopically confirmed by using P-ARIS conjugated to polystyrene latex beads with intense fluorescence. It is concluded that starfish spermatozoa have a specific receptor for ARIS on the surface of the anterior region of heads.

Species-specificity of the acrosome reaction in starfish

Zygote ◽  
1999 ◽  
Vol 8 (S1) ◽  
pp. S62-S62 ◽  
Author(s):  
Midori Matsumoto ◽  
Masako Ikeda ◽  
Motonori Hoshi
Keyword(s):  
Acrosome Reaction ◽  
Molecular Size ◽  
Type Structure ◽  
Follicle Cells ◽  
Cdna Clones ◽  
Steroid Saponin ◽  
Sperm Activation ◽  
Amino Terminal ◽  
High Calcium ◽  
Species Specific

Animal eggs are generally encased in extracellular investments. These structures are not simply a protective barrier against infectious microbes, parasites and various small predators: in starfish, three components of the egg jelly, the outermost egg investment, are responsible for triggering the acrosome reaction. These components are a highly sulphated glycoprotein of an extremely large molecular size named acrosome reaction-inducing substance (ARIS), a steroid saponin named Co-ARIS, and asteroidal sperm-activating peptides (asterosaps) (Matsui et al., 1986a, b; Nishigaki et al., 1996). ARIS can induce the acrosome reaction in homologous spermatozoa with asterosaps or Co-ARIS in normal seawater. Specificity at the genus or order level was found for sperm activation by asterosaps, whereas the acrosome reaction by jelly components was species-specific. The main sugar saccharide chain of ARIS, composed of the pentasaccharide repeating units [Xyl-Gal-Fuc(SO3−)-Fuc(3−)-Fuc-], has been observed to induce the acrosome reaction in starfish sperm at high calcium concentrations (Koyota et al., 1997). Recently, we cloned cDNAs encoding asterosaps and elucidated their nucleotide sequences (Matsumoto et al., 1999). The mRNA encoding asterosaps was transcribed only in the oocytes but not in the follicle cells, and the length was 3.7 kb. The cDNA clones contained multiple isoforms of asterosaps. We assume that asterosap cursors are large prepolypeptide chains with an unusual ‘rosary-type’ structure composed of 10 successive similar stretches of 51–55 residues. Each stretch ends with a ‘spacer’ of 17–21 residues immediately followed by the sequence of one asterosap isoform. The amino terminal of this precursor has 19–21 successive glutamine-rich repeating units.

Acrosome reaction in starfish: signal molecules in the jelly coat and their receptors

Zygote ◽  
1999 ◽  
Vol 8 (S1) ◽  
pp. S26-S27
Author(s):  
Motonori Hoshi ◽  
Takuya Nishigaki ◽  
Mayu Kawamura ◽  
Masako Ikeda ◽  
Jayantha Gunaratne ◽  
...  
Keyword(s):  
Acrosome Reaction ◽  
Sea Water ◽  
Signal Molecules ◽  
Asterias Amurensis ◽  
Signal Molecule ◽  
High Ph ◽  
Jelly Coat ◽  
Sperm Binding ◽  
High Calcium ◽  
Intracellular Ca

Animal eggs are generally encased in one or more extra-cellular coats that protect the egg from biological, chemical and mechanical hazards. These coats contain some essential molecules for sperm to fertilise an appropriate egg, such as the specific ligand for sperm binding and the specific signal for induction of the acrosome reaction. In starfish, the outermost egg coat is a relatively thick gelatinous layer called the jelly coat. When starfish sperm encounter the jelly coat of homologous eggs, they undergo the acrosome reaction within a second or less (Dale et al., 1981; Ikadai & Hoshi, 1981; Sase et al., 1995). We have thus searched the jelly coat for the signal molecule(s) that triggers the acrosome reaction in the starfish, Asterias amurensis. It is known that three components in the jelly coat, namely acrosome reaction-inducing substance (ARIS), Co-ARIS and asterosap, act in concert on homologous spermatozoa to elicit the acrosome reaction immediately and efficiently (Hoshi et al., 1994,1999).ARIS alone induces the acrosome reaction only in high calcium or high pH seawater. In normal seawater, besides ARIS, either Co-ARIS or asterosap is required for the induction. Without ARIS, no combination of Co-ARIS and asterosap can induce the acrosome reaction in normal, high calcium or high pH seawater. A mixture of ARIS and Co-ARIS increases the intracellular Ca2+ level, whereas asterosap increases the intra-cellular pH (Matsui et al., 1986a, b; Nishigaki et al., 1996). These events are prerequisites for the induction of the acrosome reaction. Indeed, the triad of ARIS, CoARIS and asterosap provides the best conditions for the induction of the acrosome reaction in normal sea-water (Hoshi et al., 1994, 1999).

Species specific binding constants of atropine to muscarinic receptors

Toxicology ◽  
2007 ◽  
Vol 233 (1-3) ◽  
pp. 238
Author(s):  
R. Bogan ◽  
H. Thiermann ◽  
L. Szinicz
Keyword(s):  
Muscarinic Receptors ◽  
Specific Binding ◽  
Binding Constants ◽  
Species Specific

scholarly journals Species-specific rDNA transcription is due to promoter-specific binding factors.

1984 ◽  
Vol 4 (2) ◽  
pp. 221-227 ◽  
Author(s):  
R Miesfeld ◽  
N Arnheim
Keyword(s):  
Rna Polymerase ◽  
Transcriptional Control ◽  
Specific Binding ◽  
Rna Polymerase I ◽  
Rdna Transcription ◽  
Nucleolar Dominance ◽  
Cell Extracts ◽  
Species Specific ◽  
Polymerase I

RNA polymerase I transcription factors were purified from HeLa and mouse L cell extracts by phosphocellulose chromatography. Three fractions from each species were found to be required for transcription. One of these fractions, virtually devoid of RNA polymerase I activity, was found to form a stable preinitiation complex with small DNA fragments containing promoter sequences from the homologous but not the heterologous species. These species-specific DNA-binding factors can explain nucleolar dominance in vivo in mouse-human hybrid somatic cells and species specificity in cell-free, RNA polymerase I-dependent transcription systems. The evolution of species-specific transcriptional control signals may be the natural outcome of a special relationship that exists between the RNA polymerase I transcription machinery and the multigene family coding for rRNA.

scholarly journals Evidence that aggregation of mouse sperm receptors by ZP3 triggers the acrosome reaction.

1989 ◽  
Vol 108 (6) ◽  
pp. 2163-2168 ◽  
Author(s):  
L Leyton ◽  
P Saling
Keyword(s):  
Acrosome Reaction ◽  
Specific Binding ◽  
Polyclonal Antibodies ◽  
Subsequent Treatment ◽  
Mouse Sperm ◽  
Fab Fragments ◽  
Sperm Binding ◽  
Extracellular Signal ◽  
Acrosomal Exocytosis ◽  
Rabbit Igg

In the mouse, considerable evidence indicates that initial sperm binding to the zona pellucida (ZP) is mediated by ZP3. In addition, this same glycoprotein is also responsible for inducing the acrosome reaction (AR). Whereas the O-linked oligosaccharides of ZP3 appear to mediate sperm-ZP binding, the portion of ZP3 bearing AR activity has not been defined. To try to understand the bifunctional role of ZP3 (binding and AR inducing activities), we have examined the hypothesis that ZP3 aggregates sperm receptor molecules. By analogy with findings in a variety of other extracellular signal transducing systems, including receptors for growth factors and insulin, this aggregation event could initiate the cascade resulting in the AR. To test this hypothesis, we have generated monospecific polyclonal antibodies against ZP2 and against ZP3, and examined the effects of these probes on capacitated sperm incubated in the absence or presence of various ZP protein preparations. For some experiments, we have used proteolytic fragments of ZP3, a preparation known to retain specific binding, but not AR-inducing, activity. We show here that capacitated mouse sperm, incubated with ZP glycopeptides, displayed ARs when incubated subsequently with anti-ZP3 IgG; ARs did not occur when parallel sperm samples were incubated with anti-ZP2 IgG or with anti-ZP3 Fab fragments. When capacitated sperm were treated successively, with (a) ZP3 glycopeptides, (b) anti-ZP3 Fab fragments, and (c) goat anti-rabbit IgG, ARs occurred in the majority of sperm. An alternative approach to examine this hypothesis used ZP proteins obtained from tubal eggs treated previously with bioactive phorbol diester (12-O-tetradecanoyl phorbol-13-acetate [TPA]). This preparation arrests capacitated sperm in an intermediate state of the AR. We demonstrate here that these sperm can be induced to undergo a complete AR by subsequent treatment with anti-ZP3 IgG. Together, these findings are consistent with the hypothesis under examination, and suggest that the aggregation of sperm molecules recognized by ZP3 glycopeptides or by TPA-treated ZP is sufficient to trigger the events that occur during acrosomal exocytosis.

Role of the cell surface in selection during transport of proteins from mother to foetus and newly born

1975 ◽  
Vol 271 (912) ◽  
pp. 395-410 ◽  
Keyword(s):  
Small Intestine ◽  
Cell Surface ◽  
Specific Binding ◽  
Molecular Size ◽  
Essential Amino Acids ◽  
Yolk Sac ◽  
Background Information ◽  
Selective Uptake ◽  
Specific Receptors ◽  
Endodermal Cells

The transport of immunoglobulins from mother to foetus and newly born mammal involves selective events which are independent of molecular size, related to immunoglobulin class, structure, and species of origin, and involve considerable protein degradation. Such events are briefly described as background information to a discussion of how selection of proteins might take place during transport across the cellular barriers concerned, namely the yolk sac splanchnopleur, chorio-allantoic placenta, and small intestine. Until recently the Brambell hypothesis has been the most favoured explanation. This implies that selection occurs intracellularly, within endodermal cells of the yolk sac splanchnopleur and small intestine, and within the syncytiotrophoblast of the chorio-allantoic placenta, of certain species. It also suggests that specific receptors are present which give attached proteins protection from degradation when the vesicles containing them fuse with lysosomes; such protected proteins are then liberated from the vesicle by exocytosis. This hypothesis is examined in the light of what is now known about the mechanism of uptake and transport of proteins by the endodermal cells and syncytiotrophoblast. It is suggested that rather than being an intracellular event, involving protection from proteolytic degradation, selection takes place at the cell surface. Evidence is presented, some direct and some circumstantial, that proteins may be selectively endocytosed by coated micropinocytotic vesicles, and non-selectively endocytosed through a complex apical canalicular system leading to macropinocytotic vesicle formation. In the small intestine of the suckling rat these two processes appear to be segregated, selective uptake occurring in the proximal half and non-selective uptake occurring in the distal half. In the endodermal cells of the rabbit yolk sac splanchnopleur, and by implication in the syncytiotrophoblast of man and monkey, it is suggested that both selective, and non-selective, uptake of protein occurs. Non-selective uptake into macropinocytotic vesicles is regarded as an event leading to complete degradation of all contained protein and functioning so as to supply the foetus and newly born mammal with essential amino acids. Selective uptake into coated micropinocytotic vesicles is regarded as an event leading to the transport of immunoglobulins across the cell without any contact with lysosomes, and functioning so as to supply the newly born mammal with protection against invasive organisms. Specific receptors are still required but only for the initial uptake and segregation of proteins into coated micropinocytotic vesicles. The role which the glycocalyx might have in such selective binding of proteins is considered and possible difficulties in characterization of specific receptors brought to light in view of the likely overwhelming need for non-specific binding to effect non-selective uptake.

Evidence for LH-inhibiting activity in ovine peripheral and testicular blood

1990 ◽  
Vol 123 (3) ◽  
pp. 345-352 ◽  
Author(s):  
V. Papapdopoulos ◽  
P. Kamtchouing ◽  
N. Boujrad ◽  
C. Pisselet ◽  
C. Perreau ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Breeding Season ◽  
Specific Binding ◽  
Apparent Molecular Weight ◽  
Rete Testis ◽  
Arterial Blood ◽  
Inhibiting Factor ◽  
Arterial Plasma ◽  
Species Specific ◽  
Venous Plasma

Abstract. Intracellular cyclic AMP and testosterone productions by purified mature rat Leydig cells were stimulated by oLH (25 μg/l) 18- and 12-fold, respectively, after a 5-h incubation period. The replacement of the incubation medium by charcoal-treated testicular venous plasma (40%, v/v) from adult rams in the breeding season induced an inhibition of cyclic AMP and testosterone productions (82 and 66%, respectively, of oLH-stimulated values). Testicular arterial plasma is less effective than testicular venous plasma, even when it originates from non-breeding season rams; in that case, testicular venous and arterial plasma strongly inhibit testosterone productions (84 and 67%, respectively of oLH-stimulated values), which probably indicates that the inhibitory activity is higher in the non-breeding season. The addition of peripheral plasma leads to a testosterone production equal to 35 and 65% of the oLH-stimulated values, respectively, for ram blood collected in non-breeding and breeding seasons. The same concentration of ovine testicular lymph or rete testis fluid is without significant effect on cyclic AMP production; however, testosterone is slightly decreased by lymph but enhanced by rete testis fluid. Increasing amounts of venous or arterial testicular blood induce a dose-related decrease of the specific binding of labelled hCG in both rat and ram testicular membranes. This inhibiting factor is present in peripheral and testicular blood of either control or hypophysectomized or castrated rams, is a protein in nature, heat-sensitive, and has an apparent molecular weight higher than 10 000 daltons. These results suggest the existence of a control of LH-specific binding to its receptors and of Leydig cell cyclic AMP and testosterone outputs; these activities are not species-specific and are more concentrated in testicular venous than in arterial blood. The origin of this inhibiting factor remains to be determined, since it is not confined to the testis and not of pituitary origin.

scholarly journals Tumor Uptake of Triazine Dendrimers Decorated with Four, Sixteen, and Sixty-Four PSMA-Targeted Ligands: Passive versus Active Tumor Targeting

Biomolecules ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 421 ◽  
Author(s):  
Jongdoo Lim ◽  
Bing Guan ◽  
Kien Nham ◽  
Guiyang Hao ◽  
Xiankai Sun ◽  
...  
Keyword(s):  
Specific Binding ◽  
Quantitative Imaging ◽  
Molecular Size ◽  
Tumor Uptake ◽  
Competitive Binding Assay ◽  
The Core ◽  
Positron Emission ◽  
Pentanedioic Acid

Various glutamate urea ligands have displayed high affinities to prostate specific membrane antigen (PSMA), which is highly overexpressed in prostate and other cancer sites. The multivalent versions of small PSMA-targeted molecules are known to be even more efficiently bound to the receptor. Here, we employ a well-known urea-based ligand, 2-[3-(1,3-dicarboxypropyl)-ureido] pentanedioic acid (DUPA) and triazine dendrimers in order to study the effect of molecular size on multivalent targeting in prostate cancer. The synthetic route starts with the preparation of a dichlorotriazine bearing DUPA in 67% overall yield over five steps. This dichlorotriazine reacts with G1, G3, and G5 triazine dendrimers bearing a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) group for 64Cu-labeling at the core to afford poly(monochlorotriazine) intermediates. Addition of 4-aminomethylpiperidine (4-AMP) and the following deprotection produce the target compounds, G1-(DUPA)4, G3-(DUPA)16, and G5-(DUPA)64. These targets include 4/16/64 DUPA groups on the surface and a DOTA group at the core, respectively. In vitro cell assay using PC3-PIP (PSMA positive) and PC3-FLU (PSMA negative) cells reveals that G1-(DUPA)4 has the highest PC3-PIP to PC3-FLU uptake ratio (10-fold) through the PSMA-mediated specific uptake. While G5-(DUPA)64 displayed approximately 12 times higher binding affinity (IC50 23.6 nM) to PC3-PIP cells than G1-(DUPA)4 (IC50 282.3 nM) as evaluated in a competitive binding assay, the G5 dendrimer also showed high non-specific binding to PC3-FLU cells. In vivo uptake of the 64Cu-labeled dendrimers was also evaluated in severe combined inmmunodeficient (SCID) mice bearing PC3-PIP and PC3-FLU xenografts on each shoulder, respectively. Interestingly, quantitative imaging analysis of positron emission tomograph (PET) displayed the lowest tumor uptake in PC3-PIP cells for the midsize dendrimer G3-(DUPA)16 (19.4 kDa) (0.66 ± 0.15%ID/g at 1 h. p.i., 0.64 ± 0.11%ID/g at 4 h. p.i., and 0.67 ± 0.08%ID/g at 24 h. p.i.). Through the specific binding of G1-(DUPA)4 to PSMA, the smallest dendrimer (5.1 kDa) demonstrated the highest PC3-PIP to muscle and PC3-PIP to PC3-FLU uptake ratios (17.7 ± 5.5 and 6.7 ± 3.0 at 4 h p.i., respectively). In addition, the enhanced permeability and retention (EPR) effect appeared to be an overwhelming factor for tumor uptake of the largest dendrimer G5-(DUPA)64 as the uptake was at a similar level irrelevant to the PSMA expression.

Variability in the Proportion and Type of Subunits in Lupin Storage Globulins

1975 ◽  
Vol 2 (1) ◽  
pp. 29 ◽  
Author(s):  
JM Gillespie ◽  
RJ Blagrove
Keyword(s):  
Protein Structure ◽  
Electrophoretic Mobility ◽  
Relative Proportion ◽  
Genetic Selection ◽  
Molecular Size ◽  
The Other ◽  
Subunit Composition ◽  
Molecular Weights ◽  
Species Specific ◽  
Conglutin Γ

The seeds of 12 species of lupin were examined and were found to contain two major globulins, conglutins α and β, while some contained a third minor globulin, conglutin �. There were considerable differences between species in the electrophoretic mobility and proportions of conglutins α and β, and in their subunit composition in terms of the number of components, their molecular weights and the importance of disulphide bonding between them. However, the electrophoretic behaviour and subunit composition of conglutins α and β did appear to be species-specific. Conglutin γ, on the other hand, did not seem to vary in molecular size or electrophoretic mobility within this genus. The 18 cultivars of Lupinus angustifolius examined appeared to be more closely related in terms of the number and size of subunits, although variations were apparent in the relative proportion of these subunits, especially with wild types. It is suggested that this variability in the protein structure of lupin globulins may provide evidence that substantial changes can be induced by genetic selection in the composition of these proteins without upsetting their structure-function relations.

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