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 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.

scholarly journals Effects of five southern California macroalgal diets on consumption, growth, and gonad weight, in the purple sea urchin Strongylocentrotus purpuratus

2014 ◽  
Author(s):  
Matthew C Foster ◽  
Jarrett E Byrnes ◽  
Daniel C Reed
Keyword(s):  
Sea Urchin ◽  
Sea Urchins ◽  
Strongylocentrotus Purpuratus ◽  
Macrocystis Pyrifera ◽  
Reproductive Capacity ◽  
Giant Kelp ◽  
Mixed Diet ◽  
Gonad Weight ◽  
Consumption Growth ◽  
Purple Sea Urchin

Consumer growth and reproductive capacity are direct functions of diet. Strongylocentrotid sea urchins, the dominant herbivores in California kelp forests, strongly prefer giant kelp (Macrocystis pyrifera), but are highly catholic in their ability to consume other species. The biomass of Macrocystis fluctuates greatly in space and time and the extent to which urchins can use alternate species of algae or a mixed diet of multiple algal species to maintain fitness when giant kelp is unavailable is unknown. We experimentally examined the effects of single and mixed species diets on consumption, growth and gonad weight in the purple sea urchin Strongylocentrotus purpuratus. Urchins were fed single species diets consisting of one of four common species of macroalgae (the kelps Macrocystis pyrifera and Pterygophora californica, and the red algae Chondracanthus corymbiferus and Rhodymenia californica (hereafter referred to by genus) or a mixed diet containing all four species ad libitum over a 13-week period in a controlled laboratory setting. Urchins fed Chondracanthus, Macrocystis and a mixed diet showed the highest growth (in terms of test diameter, wet weight and jaw length) and gonad weight while urchins fed Pterygophora and Rhodymenia showed the lowest. Urchins consumed their preferred food, Macrocystis at the highest rate when offered a mixture, but consumed Chondracanthus or Macrocystis at similar rates when the two algae were offered alone. The differences in urchin feeding behavior and growth observed between these diet types suggest the relative availability of the algae tested here could affect urchin populations and their interactions with the algal assemblage. The fact that the performance of urchins fed Chondracanthus was similar or higher than those fed the preferred Macrocystis suggests purple sea urchins could sustain growth and reproduction during times of low Macrocystis abundance as is common following large wave events.

Crosstalk between protein kinases A and C regulates sea urchin sperm motility

Zygote ◽  
2021 ◽  
pp. 1-12
Author(s):  
Arlet Loza-Huerta ◽  
Hiram Pacheco-Castillo ◽  
Alberto Darszon ◽  
Carmen Beltrán
Keyword(s):  
Protein Kinase ◽  
Sperm Motility ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Dependent Protein Kinase ◽  
Kinase C ◽  
Competitive Inhibitors ◽  
Motility Regulation ◽  
Dependent Protein ◽  
Sea Urchin Sperm

Summary Fertilization, a crucial event for species preservation, in sea urchins, as in many other organisms, requires sperm motility regulation. In Strongylocentrotus purpuratus sea urchins, speract, a sperm chemoattractant component released to seawater from the outer egg layer, attracts sperm after binding to its receptor in the sperm flagellum. Previous experiments performed in demembranated sperm indicated that motility regulation in these cells involved protein phosphorylation mainly due to the cAMP-dependent protein kinase (PKA). However, little information is known about the involvement of protein kinase C (PKC) in this process. In this work, using intact S. purpuratus sea urchin sperm, we show that: (i) the levels of both phosphorylated PKA (PKA substrates) and PKC (PKC substrates) substrates change between immotile, motile and speract-stimulated sperm, and (ii) the non-competitive PKA (H89) and PKC (chelerythrine) inhibitors diminish the circular velocity of sperm and alter the phosphorylation levels of PKA substrates and PKC substrates, while the competitive inhibitors Rp-cAMP and bisindolylmaleimide (BIM) do not. Altogether, our results show that both PKA and PKC participate in sperm motility regulation through a crosstalk in the signalling pathway. These results contribute to a better understanding of the mechanisms that govern motility in sea urchin sperm.

scholarly journals The Purple Sea Urchin Strongylocentrotus purpuratus Demonstrates a Compartmentalization of Gut Bacterial Microbiota, Predictive Functional Attributes, and Taxonomic Co-Occurrence

2019 ◽  
Vol 7 (2) ◽  
pp. 35 ◽  
Author(s):  
Joseph Hakim ◽  
Julie Schram ◽  
Aaron Galloway ◽  
Casey Morrow ◽  
Michael Crowley ◽  
...  
Keyword(s):  
Sea Urchin ◽  
High Throughput Sequencing ◽  
Sea Urchins ◽  
Community Integration ◽  
Strongylocentrotus Purpuratus ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Tide Pool ◽  
Alpha And Beta Diversity ◽  
Taxonomic Organization

The sea urchin Strongylocentrotus purpuratus (order Camarodonta, family Strongylocentrotidae) can be found dominating low intertidal pool biomass on the southern coast of Oregon, USA. In this case study, three adult sea urchins were collected from their shared intertidal pool, and the bacteriome of their pharynx, gut tissue, and gut digesta, including their tide pool water and algae, was determined using targeted high-throughput sequencing (HTS) of the 16S rRNA genes and bioinformatics tools. Overall, the gut tissue demonstrated Arcobacter and Sulfurimonas (Epsilonproteobacteria) to be abundant, whereas the gut digesta was dominated by Psychromonas (Gammaproteobacteria), Propionigenium (Fusobacteria), and Flavobacteriales (Bacteroidetes). Alpha and beta diversity analyses indicated low species richness and distinct microbial communities comprising the gut tissue and digesta, while the pharynx tissue had higher richness, more closely resembling the water microbiota. Predicted functional profiles showed Kyoto Encyclopedia of Genes and Genomes (KEGG) Level-2 categories of energy metabolism, membrane transport, cell motility, and signal transduction in the gut tissue, and the gut digesta represented amino acid, carbohydrate, vitamin and cofactor metabolisms, and replication and repair. Co-occurrence network analysis showed the potential relationships and key taxa, such as the highly abundant Arcobacter and Propionigenium, influencing population patterns and taxonomic organization between the gut tissue and digesta. These results demonstrate a trend of microbial community integration, allocation, predicted metabolic roles, and taxonomic co-occurrence patterns in the S. purpuratus gut ecosystem.

scholarly journals Chloroquine augments the binding of insulin to its receptor

1995 ◽  
Vol 311 (3) ◽  
pp. 787-795 ◽  
Author(s):  
A P Bevan ◽  
J R Christensen ◽  
J Tikerpae ◽  
G D Smith
Keyword(s):  
Binding Sites ◽  
Slow Component ◽  
Insulin Binding ◽  
Dissociation Rate ◽  
Receptor Interaction ◽  
Dependent Manner ◽  
Binding Model ◽  
Binding Data ◽  
Plasma Membrane Receptor ◽  
Dissociation Rate Constants

The effect of chloroquine on the interaction of insulin with its receptor has been investigated under both equilibrium and non-equilibrium conditions. Chloroquine was found to augment insulin binding in a pH-dependent manner between pH 6.0 and pH 8.5, with the maximum occurring at approximately pH 7.0. Analysis of the equilibrium binding data in terms of independent binding sites gave equivocal results but suggested an increase in the high-affinity component. Analysis using the negative co-operativity binding model of De Meyts, Bianco and Roth [J. Biol. Chem. (1976) 251, 1877-1888] suggested that the affinity at both high and low occupancy was increased equally. The kinetics of association of insulin with the plasma-membrane receptor indicated that, although the net rate of association increased in the presence of chloroquine, this was due to a reduction in the dissociation rate rather than an increase in the association rate. This was confirmed by direct measurement of the rates of dissociation. Dissociation was found to be distinctly biphasic, with fast and slow components. Curve fitting suggested that the decrease in dissociation rate in the presence of chloroquine was not due to a decrease in either of the two dissociation rate constants, but rather to an increase in the amount of insulin dissociating by the slow component. It was also found that the increase in dissociation rate in the presence of excess insulin, ascribed to negative co-operativity, could be accounted for by an increase in the amount of insulin dissociating by the faster pathway, rather than by an increase in the dissociation rate constant. Thus chloroquine appears to have the opposite effect to excess insulin, and evidence was found for the induction of positive co-operativity in the insulin-receptor interaction at high chloroquine concentrations. Evidence was also found for the presence of low-affinity chloroquine binding sites with binding parameters similar to the concentration dependence of the chloroquine-induced augmentation of insulin binding.

scholarly journals Ligands and receptors mediating signal transduction in sea urchin spermatozoa

Reproduction ◽  
2004 ◽  
Vol 127 (2) ◽  
pp. 141-149 ◽  
Author(s):  
Anna T Neill ◽  
Victor D Vacquier
Keyword(s):  
Signal Transduction ◽  
Plasma Membrane ◽  
Signaling Pathways ◽  
Sea Urchin ◽  
Acrosome Reaction ◽  
Sea Urchins ◽  
Model System ◽  
Surrounding Seawater ◽  
Sea Urchin Sperm

Sea urchins have long been a model system for the study of fertilization. Much has been learned about how sea urchin sperm locate and fertilize the egg. Sperm and eggs are spawned simultaneously into the surrounding seawater. Sperm signaling pathways lead to downstream events that ensure fertilization. Upon spawning, sperm must acquire motility and then they must swim towards or respond to the egg in some way. Finally, they must undergo a terminal exocytotic event known as the acrosome reaction that allows the sperm to bind to the vitelline layer of the egg and then to fuse with the egg plasma membrane. Motility is stimulated by exposure to seawater, while later events are orchestrated by factors from the egg. The sperm signaling pathways are exquisitely tuned to bring the sperm to the egg, bind, and fuse the two cells as quickly as possible.

scholarly journals Effects of five southern California macroalgal diets on consumption, growth, and gonad weight, in the purple sea urchin Strongylocentrotus purpuratus

2014 ◽  
Author(s):  
Matthew C Foster ◽  
Jarrett E Byrnes ◽  
Daniel C Reed
Keyword(s):  
Sea Urchin ◽  
Sea Urchins ◽  
Strongylocentrotus Purpuratus ◽  
Macrocystis Pyrifera ◽  
Reproductive Capacity ◽  
Giant Kelp ◽  
Mixed Diet ◽  
Gonad Weight ◽  
Consumption Growth ◽  
Purple Sea Urchin

Consumer growth and reproductive capacity are direct functions of diet. Strongylocentrotid sea urchins, the dominant herbivores in California kelp forests, strongly prefer giant kelp (Macrocystis pyrifera), but are highly catholic in their ability to consume other species. The biomass of Macrocystis fluctuates greatly in space and time and the extent to which urchins can use alternate species of algae or a mixed diet of multiple algal species to maintain fitness when giant kelp is unavailable is unknown. We experimentally examined the effects of single and mixed species diets on consumption, growth and gonad weight in the purple sea urchin Strongylocentrotus purpuratus. Urchins were fed single species diets consisting of one of four common species of macroalgae (the kelps Macrocystis pyrifera and Pterygophora californica, and the red algae Chondracanthus corymbiferus and Rhodymenia californica (hereafter referred to by genus) or a mixed diet containing all four species ad libitum over a 13-week period in a controlled laboratory setting. Urchins fed Chondracanthus, Macrocystis and a mixed diet showed the highest growth (in terms of test diameter, wet weight and jaw length) and gonad weight while urchins fed Pterygophora and Rhodymenia showed the lowest. Urchins consumed their preferred food, Macrocystis at the highest rate when offered a mixture, but consumed Chondracanthus or Macrocystis at similar rates when the two algae were offered alone. The differences in urchin feeding behavior and growth observed between these diet types suggest the relative availability of the algae tested here could affect urchin populations and their interactions with the algal assemblage. The fact that the performance of urchins fed Chondracanthus was similar or higher than those fed the preferred Macrocystis suggests purple sea urchins could sustain growth and reproduction during times of low Macrocystis abundance as is common following large wave events.

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