scholarly journals Participation of a K+ Channel Modulated Directly by cGMP in the Speract-Induced Signaling Cascade of Strongylocentrotus purpuratus Sea Urchin Sperm

2000 ◽  
Vol 221 (2) ◽  
pp. 285-294 ◽  
Author(s):  
Blanca Estela Galindo ◽  
Carmen Beltrán ◽  
Edward J. Cragoe ◽  
Alberto Darszon
Keyword(s):  
Sea Urchin ◽  
Strongylocentrotus Purpuratus ◽  
Signaling Cascade ◽  
K Channel ◽  
Sea Urchin Sperm

scholarly journals Properties of an antiserum against native dynein 1 from sea urchin sperm flagella.

1977 ◽  
Vol 73 (1) ◽  
pp. 182-192 ◽  
Author(s):  
K Ogawa ◽  
D J Asai ◽  
C J Brokaw
Keyword(s):  
Atpase Activity ◽  
Sea Urchin ◽  
Strongylocentrotus Purpuratus ◽  
Beat Frequency ◽  
Bend Angle ◽  
Tryptic Fragment ◽  
Effective Inhibition ◽  
Dynein Arms ◽  
Sea Urchin Sperm ◽  
Anthocidaris Crassispina

Effects of an antiserum against native dynein 1 from sperm flagella of the sea urchin Strongylocentrotus purpuratus were compared with effects of an antiserum previously obtained against an ATPase-active tryptic fragment (fragment 1A) of dynein 1 from sperm flagella of the sea urchin, Anthocidaris crassispina. Both antisera precipitate dynein 1 and do not precipitate dynein 2. Only the fragment 1A antiserum precipitates fragment 1A and produces a measurable inhibition of dynein 1 ATPase activity. Both antisera inhibit the movement and the movement-coupled ATP dephosphorylation of reactivated spermatozoa. The inhibition of movement by the antiserum against dynein 1 is much less than by the antiserum against fragment 1A, suggesting that a specific interference with the active ATPase site may be required for effective inhibition of movement. Both antisera reduce the bend angle as well as the beat frequency of reactivated S. purpuratus spermatozoa, suggesting that the bend angle may depend on the activity of the dynein arms which generate active sliding.

Possible Participation of a cAMP Regulated K+ Channel from the Sea Urchin Sperm in the Speract Response

1997 ◽  
pp. 147-168
Author(s):  
Pedro Labarca ◽  
Celia Santi ◽  
Otilia Zapata ◽  
Carmen Beltrán ◽  
Arturo Liévano ◽  
...  
Keyword(s):  
Sea Urchin ◽  
K Channel ◽  
Sea Urchin Sperm

Speract-receptor interaction and the modulation of ion transport in Strongylocentrotus purpuratus sea urchin sperm

Zygote ◽  
1999 ◽  
Vol 8 (S1) ◽  
pp. S20-S21 ◽  
Author(s):  
Blanca-Estela Galindo ◽  
Takuya Nishigaki ◽  
Esmeralda Rodríguez ◽  
Daniel Sánchez ◽  
Camen Beltrán ◽  
...  
Keyword(s):  
Ion Transport ◽  
Sea Urchin ◽  
Conformational Changes ◽  
Sea Urchins ◽  
Strongylocentrotus Purpuratus ◽  
Dissociation Rate ◽  
Receptor Interaction ◽  
Jelly Coat ◽  
Dissociation Rate Constants ◽  
Sea Urchin Sperm

We are studying the regulation of ion transport in sperm physiology. Sperm ion permeability is modulated by components from the outer layer of the egg which, depending on the species, regulate sperm motility, Chemotaxis and the acrosome reaction (AR). This reaction is required for sperm to fertilise the egg in many species from sea urchins to man (Darszon et al., 1999).Speract, a decapeptide from the external layer of Strongylocentrotus purpuratus sea urchin eggs, influences sperm respiration, motility and possibly the AR. Signal transduction starts when speract binds to a protein of 77 kDa closely coupled to sperm guanylyl cyclase (Garbers, 1989). Our recent receptor binding experiments using fluorescent-labelled speract (fluorescein and rhodamine) have allowed estimates of the association (kon 2.4 × 107 M−1s−1) and dissociation rate constants (koff 1.3 × 10−4 s−1). Furthermore, studies with fluorescent speract analogues indicate that the receptor undergoes conformational changes that depend on intracellular pH (pHi). The overall results are consistent with the possibility that speract may induce in sea urchin sperm a hyperactivated-like flagellar movement inside the jelly coat to accelerate sperm penetration through this layer.

Cannabinoids reduce fertility of sea urchin sperm

1987 ◽  
Vol 65 (2) ◽  
pp. 130-136 ◽  
Author(s):  
Herbert Schuel ◽  
Regina Schuel ◽  
Arthur M. Zimmerman ◽  
Selma Zimmerman
Keyword(s):  
Adverse Effect ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Strongylocentrotus Purpuratus ◽  
Dependent Manner ◽  
Dose Dependent ◽  
Sea Urchin Sperm

Cannabinoids are potent pharmacological substances derived from marihuana. The effects of Δ9-tetrahydrocannabinol (THC), cannabinol (CBN), and cannabidiol (CBD) on fertilization in the sea urchin Strongylocentrotus purpuratus were investigated. Insemination of THC-treated eggs (5–400 μM) with excess sperm did not result in polyspermic fertilization. At minimal sperm densities, THC (0.1–10 μM) inhibited fertilization in a dose-dependent manner. Pretreatment of eggs with THC did not reduce their receptivity to sperm. Pretreatment of sperm with THC reduced their fertilizing capacity. The concentration of THC required to reduce sperm fertility by 50% was 1.1 ± 1.1 μM. The fertilizing capacity of THC-treated sperm depended on concentration of sperm and duration of pretreatment. The fertility of sperm at minimal densities was reduced by 50% at 129.3 ± 43 s treatment with 10 μM THC. The adverse effect of THC on sperm fertility was reversible. CBN and CBD at comparable concentrations (0.1–10 μM) inhibited fertilization in a manner similar to THC. First division was not delayed in zygotes that were fertilized with sperm pretreated with 10 μM THC. These studies show that cannabinoids directly affect the process of fertilization in sea urchins by reducing the fertilizing capacity of sperm.

scholarly journals Involvement of zinc in the regulation of pHi, motility, and acrosome reactions in sea urchin sperm.

1985 ◽  
Vol 100 (6) ◽  
pp. 1817-1824 ◽  
Author(s):  
D L Clapper ◽  
J A Davis ◽  
P J Lamothe ◽  
C Patton ◽  
D Epel
Keyword(s):  
Sperm Motility ◽  
Sea Urchin ◽  
Acrosome Reaction ◽  
Strongylocentrotus Purpuratus ◽  
Metal Chelators ◽  
Lytechinus Pictus ◽  
Low Levels ◽  
Monensin A ◽  
Sea Urchin Sperm ◽  
Phi Regulation

When sperm of Strongylocentrotus purpuratus or Lytechinus pictus are diluted into seawater, motility is initiated; and when exposed to egg jelly, an acrosome reaction is induced. In the presence of a variety of structurally different metal chelators (0.1-1 mM EDTA, EGTA, phenanthroline, dipyridyl, cysteine, or dithiothreitol), motility initiation is delayed and the acrosome reaction is inhibited. Of the metals detected in the sperm of these two species, very low levels of Zn+2 (0.1 microM free Zn+2) uniquely prevent this chelator inhibition. L. pictus sperm concentrate 65Zn+2 from seawater, and EDTA removes 50% of the accumulated 65Zn+2 by 5 min. Since both sperm motility and acrosome reactions are in part regulated by intracellular pH (pHi), the effect of chelators on the sperm pHi was examined by using the fluorescent pH sensitive probe, 9-aminoacridine, EDTA depresses sperm pHi in both species, and 0.1 microM free Zn+2 reverses this pHi depression. When sperm are diluted into media that contain chelators, both NH4Cl and monensin (a Na+/H+ ionophore) increase the sperm pHi and reverse the chelator inhibition of sperm motility and acrosome reactions. The results of this study are consistent with the involvement of a trace metal (probably zinc) in the pHi regulation of sea urchin sperm and indicate a likely mechanism for the previously observed effects of chelators on sperm motility and acrosome reactions.

Sea urchin sperm peroxidase is competitively inhibited by benzohydroxamic acid and phenylhydrazine

1986 ◽  
Vol 64 (12) ◽  
pp. 1333-1338 ◽  
Author(s):  
Herbert Schuel ◽  
Regina Schuel
Keyword(s):  
Sea Urchin ◽  
Strongylocentrotus Purpuratus ◽  
Kinetic Studies ◽  
Biochemical Properties ◽  
Benzohydroxamic Acid ◽  
Somatic Tissues ◽  
Competitive Inhibitors ◽  
Triton X ◽  
Tetramethyl Benzidine ◽  
Sea Urchin Sperm

Sea urchin sperm contain a phenylhydrazine-sensitive peroxidase that is believed to use hydrogen peroxide produced by the fertilized egg to reduce sperm fertility and thereby assist in the prevention of polyspermy. Strongylocentrotus purpuratus sperm were treated initially with hypotonic phosphate buffer (pH 7.0) to remove catalase and then extracted with 0.5% Triton X-100 in 0.5 M acetate buffer (pH 5.0). Peroxidase activity in this detergent extract was assayed using 3,3′,5,5′-tetramethyl benzidine (TMB) as oxidizable substrate. Kinetic studies showed that the Km for TMB is 250 μM. Benzohydroxamic acid and phenylhydrazine are known to be competitive inhibitors of a variety of plant and animal peroxidases. These substances were found to competitively inhibit the sea urchin sperm peroxidase: for benzohydroxamic acid, Ki = 51.2 μM, mean inhibitory dose (ID50) = 146.7 μM; for phenylhydrazine, Ki = 201 nM, ID50 = 303 nM. These findings (i) indicate that the biochemical properties of the sea urchin sperm peroxidase resembles those of peroxidases found in somatic tissues where oxygen radicals are produced by phagocytes to kill bacteria and (ii) support our hypothesis that the sperm peroxidase has a functional role in the prevention of polyspermy during fertilization.

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