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Marine invertebrate oocytes establish chemoattractant gradients that guide spermatozoa towards their source. In sea urchin spermatozoa, this relocation requires coordinated motility changes initiated by Ca(2+)-driven alterations in sperm flagellar curvature. We discovered that Lytechinus pictus spermatozoa undergo chemotaxis in response to speract, an(More)
Sperm chemotaxis is a long-term puzzle and most of our knowledge comes from studying marine animals that are external fertilizers. Sperm are attracted by diffusible chemical factors (chemoattractants) released from the egg which redirect their swimming paths towards their source. This redirection is driven by increases in flagellar curvature that correlate(More)
The influx of Ca2+ and its subsequent intracellular increase are required for the acrosome reaction of sea urchin sperm to occur. Spermatozoa must undergo this reaction, which is triggered by the egg jelly, in order to fertilize the egg. Here, the egg jelly-induced Ca2+ influx mechanisms have been studied in sperm loaded with FURA-2 using Mn2+ under the(More)
Progesterone is a physiological agonist for mammalian sperm, modulating its flagellar movement and facilitating the acrosome reaction. To study the initial action of progesterone, we developed a caged analog with a photosensitive group: nitrophenylethanediol, at position 20. Using this compound combined with stroboscopic illumination, we performed Ca(2)(+)(More)
Internal organs are asymmetrically positioned inside the body. Embryonic motile cilia play an essential role in this process by generating a directional fluid flow inside the vertebrate left-right organizer. Detailed characterization of how fluid flow dynamics modulates laterality is lacking. We used zebrafish genetics to experimentally generate a range of(More)
Echinoderm sperm use cyclic nucleotides (CNs) as essential second messengers to locate and swim towards the egg. Sea urchin sperm constitute a rich source of membrane-bound guanylyl cyclase (mGC), which was first cloned from sea urchin testis by the group of David Garbers. His group also identified speract, the first sperm-activating peptide (SAP) to be(More)
Sperm motility, crucial for fertilization, has been mostly studied in two dimensions (2D) by recording their swimming trajectories near a flat surface. However, spermatozoa swim in three-dimensions (3D) to find eggs, with their speed being the main impediment to track them under realistic conditions. Here, we describe a novel method allowing 3D tracking and(More)
The spermatozoon must find its female gamete partner and deliver its genetic material to generate a new individual. This requires that the spermatozoon be motile and endowed with sophisticated swimming strategies to locate the oocyte. A common strategy is chemotaxis, in which spermatozoa detect and follow a gradient of chemical signals released by the egg(More)
The acrosome reaction (AR) is an exocytotic event that allows sperm to recognize and fuse with the egg. In the sea urchin sperm this reaction is triggered by the outer investment of the egg, the jelly, which induces ionic movements leading to increases in intracellular Ca2+ ([Ca2+]i) and intracellular pH (pHi), a K(+)-dependent transient hyperpolarization(More)
Ionic fluxes are deeply involved in the response of spermatozoa to the egg. Using the patch-clamp technique, we show for the first time single ion channel activity in sea urchin spermatozoa and spermatozoa heads. Due to their small size gigaseals were obtained in suspended cells by applying suction through the pipette. The rate of gigaseal formation was(More)