Progression of Flagellar Stages during Artificially Delayed Motility Initiation in Sea Urchin Sperm

Ohmuro, Junko; Mogami, Yoshihiro; Baba, Shoji A.

doi:10.2108/zsj.21.1099

Cited by 14 publications

(8 citation statements)

References 46 publications

(53 reference statements)

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“…To measure moving behavior, downlinked video images of swimming C. elegans were converted to dark-field images, and the positions of individuals were determined using Bohboh tracking software (Bohboh Soft, Tokyo, Japan). 47 The means of frequency, phase, and amplitude were calculated from changes in distance at specific time intervals (30 f.p.s.). Considering the individual differences between worm body lengths (L), the wavelength of motion was calculated as a function of L. Curves were plotted as cosine functions of time fitted to measurements by the least squares method.…”

Section: Methodsmentioning

confidence: 99%

Microgravity elicits reproducible alterations in cytoskeletal and metabolic gene and protein expression in space-flown Caenorhabditis elegans

et al. 2016

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Although muscle atrophy is a serious problem during spaceflight, little is known about the sequence of molecular events leading to atrophy in response to microgravity. We carried out a spaceflight experiment using Caenorhabditis elegans onboard the Japanese Experiment Module of the International Space Station. Worms were synchronously cultured in liquid media with bacterial food for 4 days under microgravity or on a 1-G centrifuge. Worms were visually observed for health and movement and then frozen. Upon return, we analyzed global gene and protein expression using DNA microarrays and mass spectrometry. Body length and fat accumulation were also analyzed. We found that in worms grown from the L1 larval stage to adulthood under microgravity, both gene and protein expression levels for muscular thick filaments, cytoskeletal elements, and mitochondrial metabolic enzymes decreased relative to parallel cultures on the 1-G centrifuge (95% confidence interval (P⩽0.05)). In addition, altered movement and decreased body length and fat accumulation were observed in the microgravity-cultured worms relative to the 1-G cultured worms. These results suggest protein expression changes that may account for the progressive muscular atrophy observed in astronauts.

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Section: Methodsmentioning

confidence: 99%

Microgravity elicits reproducible alterations in cytoskeletal and metabolic gene and protein expression in space-flown Caenorhabditis elegans

et al. 2016

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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]. Tantalising initial work suggests that chemotaxis and other forms of motility modulation may also be critical to human fertilisation [Spehr et al, 2003[Spehr et al, , 2006Eisenbach and Giojalas, 2006;Teves et al, 2006;Eisenbach, 2007], but a crucial difference between marine and internal fertilisation is the viscosity of the fluid environment.…”

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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“…The flagellar beat waveforms were analyzed using motion analysis software [Bohboh ver. 4.33; BohbohSoft, Tokyo, Japan; Ohmuro et al, ]. First, using an automatic tracking function of the motion analyzer, the XY ‐coordinates along the center line of a flagellar shaft were obtained for each spermatozoa image (total 100 frames for 0.5 s).…”

Section: Methodsmentioning

confidence: 99%

Effects of the dynein inhibitor ciliobrevin on the flagellar motility of sea urchin spermatozoa

2015

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Ciliobrevin has recently been found to be a membrane-permeable inhibitor that is specific to AAA+ molecular motors such as cytoplasmic dyneins. In this study, we investigated how ciliobrevin inhibited the motility of sperm from sea urchins: Hemicentrotus pulcherrimus, Pseudocentrotus depressus, and Anthocidaris crassispina. After application of 100 μM of ciliobrevin A to live spermatozoa, swimming speed decreased gradually and flagellar motion stopped almost completely within 5 to 10 min. This inhibition was reversible and the frequency of flagellar beating was reduced in a concentration-dependent manner. Ciliobrevin had similar inhibitory effects on the flagellar beating of demembranated and reactivated sperm and the sliding disintegration of trypsin-treated axonemes. We also analyzed the curvature and shear angle of the beating flagella and found that the proximal region of the sperm flagellum was less sensitive to ciliobrevin compared with more distal regions, where bending motions were blocked completely. Interestingly, the shear angle analysis of flagellar motility showed that ciliobrevin induced highly asymmetric bends in the proximal region of the flagellum. These results suggest that there is heterogeneity in the inhibitory thresholds of dynein motors, which depend on the regions along the flagellar shaft (proximal or distal) and on the sites of doublets in the flagellar cross-section (doublet numbers). We expect that it will be possible to map the functional differences in dynein subtypes along and/or around the cross-sections of flagellar axonemes by analyzing the inhibitory effects of ciliobrevin.

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Progression of Flagellar Stages during Artificially Delayed Motility Initiation in Sea Urchin Sperm

Cited by 14 publications

References 46 publications

Microgravity elicits reproducible alterations in cytoskeletal and metabolic gene and protein expression in space-flown Caenorhabditis elegans

Microgravity elicits reproducible alterations in cytoskeletal and metabolic gene and protein expression in space-flown Caenorhabditis elegans

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

Effects of the dynein inhibitor ciliobrevin on the flagellar motility of sea urchin spermatozoa

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