Sperm-Activating Peptide Induces Asymmetric Flagellar Bending in Sea Urchin Sperm

Shiba, Kogiku; Ohmuro, Junko; Mogami, Yoshihiro; Nishigaki, Takuya; Wood, Christopher D.; Darszon, Alberto; Tatsu, Yoshiro; Yumoto, Noboru; Baba, Shoji A.

doi:10.2108/zsj.22.293

Cited by 26 publications

(17 citation statements)

References 29 publications

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“…The body shapes of the larvae in the captured images were analyzed with BohBoh (BohBoh Software), a motion tracker/shape analyzer originally developed for the analysis of flagellar or ciliar beating (Baba and Mogami, 1985;Shiba et al, 2005;Wood et al, 2005). The higherresolution images captured with the Fastcam Ultima 1024 (1024 ϫ 512 pixels) were used for the analyses.…”

Section: Methodsmentioning

confidence: 99%

Functional Role of a Specialized Class of Spinal Commissural Inhibitory Neurons during Fast Escapes in Zebrafish

Satou¹,

Kimura²,

Kohashi³

et al. 2009

J. Neurosci.

143

157

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In teleost fish, the Mauthner (M) cell, a large reticulospinal neuron in the brainstem, triggers escape behavior. Spinal commissural inhibitory interneurons that are electrotonically excited by the M-axon have been identified, but the behavioral roles of these neurons have not yet been addressed. Here, we studied these neurons, named CoLo (commissural local), in larval zebrafish using an enhancer-trap line in which the entire population of CoLos was visualized by green fluorescent protein. CoLos were present at one cell per hemi-segment. Electrophysiological recordings showed that an M-spike evoked a spike in CoLos via electrotonic transmission and that CoLos made monosynaptic inhibitory connections onto contralateral primary motoneurons, consistent with the results in adult goldfish. We further showed that CoLos were active only during escapes. We examined the behavioral roles of CoLos by investigating escape behaviors in CoLo-ablated larvae. The results showed that the escape behaviors evoked by sound/vibration stimuli were often impaired with a reduced initial bend of the body, indicating that CoLos play important roles in initiating escapes. We obtained several lines of evidence that strongly suggested that the impaired escapes occurred during bilateral activation of the M-cells: in normal larvae, CoLo-mediated inhibitory circuits enable animals to perform escapes even in these occasions by silencing the output of the slightly delayed firing of the second M-cell. This study illustrates (1) a clear example of the behavioral role of a specialized class of interneurons and (2) the capacity of the spinal circuits to filter descending commands and thereby produce the appropriate behavior.

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Section: Methodsmentioning

confidence: 99%

Functional Role of a Specialized Class of Spinal Commissural Inhibitory Neurons during Fast Escapes in Zebrafish

Satou¹,

Kimura²,

Kohashi³

et al. 2009

J. Neurosci.

143

157

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“…These peptides diffuse away from the egg jelly and promote an activation of sperm metabolism and increase in flagellar motility (Shiba et al, 2005). Speract, the sperm-activating decapeptide from S. purpuratus, induces changes in intracellular Ca 2+ , Na + , cAMP, cGMP, and pH (Darszon et al, 2007).…”

Section: Isoforms Of Sulfated Fucansmentioning

confidence: 99%

The structure of sulfated polysaccharides ensures a carbohydrate-based mechanism for species recognition during sea urchin fertilization

Vilela-Silva

Hirohashi²,

Mourāo

2008

Int. J. Dev. Biol.

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The evolution of barriers to inter-specific hybridization is a crucial step in the fertilization of free spawning marine invertebrates. In sea urchins, molecular recognition between sperm and egg ensures species recognition. Here we review the sulfated polysaccharide-based mechanism of sperm-egg recognition in this model organism. The jelly surrounding sea urchin eggs is not a simple accessory structure; it is molecularly complex and intimately involved in gamete recognition. It contains sulfated polysaccharides, sialoglycans and peptides. The sulfated polysaccharides have unique structures, composed of repetitive units of α-L-fucose or α-Lgalactose, which differ among species in the sulfation pattern and/or the position of the glycosidic linkage. The egg jelly sulfated polysaccharides show species-specificity in inducing the sperm acrosome reaction, which is regulated by the structure of the saccharide chain and its sulfation pattern. Other components of the egg jelly do not possess acrosome reaction inducing activity, but sialoglycans act in synergy with the sulfated polysaccharide, potentiating its activity. The system we describe establishes a new view of cell-cell interaction in the sea urchin model system. Here, structural changes in egg jelly polysaccharides modulate cell-cell recognition and speciesspecificity leading to exocytosis of the acrosome. Therefore, sulfated polysaccharides, in addition to their known functions as growth factors, coagulation factors and selectin binding partners, also function in fertilization. The differentiation of these molecules may play a role in sea urchin speciation.

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“…Elegant research has elucidated in detail the mechanisms of sperm motility and chemotaxis in external fertilising marine animals such as sea urchins and starfish [Ward et al, 1985;Wood et al, 2003;Nishigaki et al, 2004;Bohmer et al, 2005;Shiba et al, 2005]. This work has rapidly advanced to encompass details of motility regulation by calcium signalling, cAMP, and peptides such as speract [Ohmuro et al, 2004;Shiba et al, 2005Shiba et al, , 2006Kinukawa et al, 2006;Wood et al, 2007].…”

Section: Introductionmentioning

confidence: 99%

Bend propagation in the flagella of migrating human sperm, and its modulation by viscosity

Smith

Gaffney

Gadêlha

et al. 2009

Cell Motil. Cytoskeleton

204

270

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A pre-requisite for sexual reproduction is successful unification of the male and female gametes; in externally-fertilising echinoderms the male gamete is brought into close proximity to the female gamete through chemotaxis, the associated signalling and flagellar beat changes being elegantly characterised in several species. In the human, sperm traverse a relatively high-viscosity mucus coating the tract surfaces, there being a tantalising possible role for chemotaxis. To understand human sperm migration and guidance, studies must therefore employ similar viscous in vitro environments. High frame rate digital imaging is used for the first time to characterise the flagellar movement of migrating sperm in low and high viscosities. While qualitative features have been reported previously, we show in precise spatial and temporal detail waveform evolution along the flagellum. In low viscosity the flagellum continuously moves out of the focal plane, compromising the measurement of true curvature, nonetheless the presence of torsion can be inferred. In high viscosities curvature can be accurately determined and we show how waves propagate at approximately constant speed. Progressing waves increase in curvature approximately linearly except for a sharper increase over a distance approximately 20-27 microm from the head/midpiece junction. Curvature modulation, likely influenced by the outer dense fibres, creates the characteristic waveforms of high viscosity swimming, with remarkably effective cell progression against greatly increased resistance, even in high viscosity liquids. Assessment of motility in physiological viscosities will be essential in future basic research, studies of chemotaxis and novel diagnostics.

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Sperm-Activating Peptide Induces Asymmetric Flagellar Bending in Sea Urchin Sperm

Cited by 26 publications

References 29 publications

Functional Role of a Specialized Class of Spinal Commissural Inhibitory Neurons during Fast Escapes in Zebrafish

Functional Role of a Specialized Class of Spinal Commissural Inhibitory Neurons during Fast Escapes in Zebrafish

The structure of sulfated polysaccharides ensures a carbohydrate-based mechanism for species recognition during sea urchin fertilization

Bend propagation in the flagella of migrating human sperm, and its modulation by viscosity

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