Endogenous substrate for energy metabolism and ultrastructural correlates in spermatozoa of the sea urchin <i>Diadema setosum</i>

Mita, Masatoshi; Yasumasu, Ikuo; Nakamura, Masaru

doi:10.1002/mrd.1080400113

Cited by 6 publications

(5 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As with the two regular urchins from NZ, a deep centriolar fossa is described in other regular urchins such as Arbacia punctulata ( Lamarck 1816) (Franklin ), S. droebachiensis (Afzelius & Murray ) and the diadematoid Diadema setosum ( Leske 1778) Mita et al. ). In comparison, the shallow centriolar fossa in the irregular urchins F. zelandiae and E. cordatum is a characteristic shared with other irregular species such as Clypeaster japonicus ( Döderlein 1885) (Mita & Nakamura ) and Echinarachnius parma ( Lamarck 1816) (Summers & Hylander ).…”

Section: Discussionmentioning

confidence: 88%

Comparative ultrastructure of spermatozoa from two regular and two irregular New Zealand echinoids

Hudson

Sewell

2015

Invertebrate Biology

View full text Add to dashboard Cite

Spermatozoa from four species of echinoids found in New Zealand had morphological characteristics typical of other echinoids, including a conical sperm head with an acrosome-capped nucleus, a midpiece, and a single long flagellum. The spermatozoa of Fellaster zelandiae, Echinocardium cordatum, Evechinus chloroticus, and Centrostephanus rodgersii also showed statistically significant differences in species-specific morphological characteristics. Evechinus chloroticus showed the most variable sperm morphology. The irregular urchins (F. zelandiae and E. cordatum) had short, wide sperm heads (head length: width ratios 2.93:1 & 2.97:1, respectively) with a long acrosome complex, while the regular urchins (E. chloroticus and C. rodgersii) had longer, narrower heads with a short acrosome complex (ratios 5.29:1 & 3.37:1). Spermatozoa of E. cordatum from the New Zealand population shared more characteristics with those of conspecifics from the Sea of Japan than those of conspecifics from the Baltic, reflecting the membership of the former two populations in a distinct Pacific clade. Volumetric calculations showed no evidence of phylogenetic grouping. Mitochondria of E. chloroticus spermatozoa were less than half the volume of those of C. rodgersii and E. cordatum, and those of F. zelandiae were intermediate in volume. These volume measurements will be useful in physiological studies of sperm performance and quality.

show abstract

Section: Discussionmentioning

confidence: 88%

Comparative ultrastructure of spermatozoa from two regular and two irregular New Zealand echinoids

Hudson

Sewell

2015

Invertebrate Biology

View full text Add to dashboard Cite

show abstract

“…), two features of sperm morphology that may influence sperm performance (SeGall and Lennarz ; Mita et al ). The volume of mitochondria and their associated energy stores have been demonstrated to be important for long‐term activity of sperm in broadcast spawning invertebrates (Afzelius and Mohri ; Mita et al ), suggesting that sperm with larger mitochondrial packets may live longer and thereby increase their chance of participating in fertilizations. Larger acrosomes could also confer a fertilization advantage.…”

Section: Discussionmentioning

confidence: 99%

“…Sperm longevity is often hypothesized to be important for fertilization success, especially under sperm-limited conditions when the average time until sperm-egg encounters is low (Levitan 1993;Williams and Bentley 2002;Johnson and Yund 2004;Pizzari et al 2008). Although the morphological correlates of longevity are often unclear, there is some evidence that longevity may be related to energy reserves and associated storage structures such as mitochondria (Afzelius and Mohri 1966;Mita et al 1995).…”

mentioning

confidence: 99%

The Maintenance of Sperm Variability: Context-Dependent Selection on Sperm Morphology in a Broadcast Spawning Invertebrate

2012

View full text Add to dashboard Cite

Why are sperm so variable despite having a singular, critical function and an intimate relationship with fitness? A key to understanding the evolution of sperm morphology is identifying which traits enable sperm to be successful fertilizers. Several sperm traits (e.g., tail length, overall size) are implicated in sperm performance, but the benefits of these traits are likely to be highly context dependent. Here, we examined phenotypic selection on sperm morphology of a broadcast spawning tube worm (Galeolaria gemineoa). We conducted laboratory experiments to measure the relationship between average sperm morphology and relative fertilization success across a range of sperm environments that were designed to approximate the range of sperm concentrations and ages encountered by eggs in nature. We found that the strength and form of multivariate selection varied substantially across our environmental gradients. Sperm with long tails and small heads were favored in high-concentration environments, whereas sperm with long heads were favored at low concentrations and old ages. We suggest variation in the local fertilization environment and resulting differences in selection can preserve variability in sperm morphology both within and among males. Some of the most fundamental and enduring questions in evolutionary biology concern the evolution of gamete size and morphology (e.g., Kalmus 1932; Scudo 1967). The evolutionary forces shaping gamete morphology may be nuanced, complex, and are incompletely understood (see reviews by Randerson and Hurst 2001;Snook 2005). There has been a sustained and intense effort by theoreticians to model the evolution of anisogamy (small sperm and large eggs; Parker et al. 1972, Parker 1982Levitan 1993;Dusenbery 2000;Lehtonen and Kokko 2011), but the assumptions underlying these models have received less empirical attention. In particular, although it now seems clear that males that produce more sperm may often secure more fertilizations, the role of sperm quality has been less explored. Indeed, a recent focus on sperm quality has highlighted the importance of understanding the evolutionary forces that shape not only sperm size, but also fertilization performance and its morphological underpinnings (reviewed by Snook 2005).Although formal analyses of selection on sperm morphology are rare, one line of evidence to suggest an adaptive role for sperm morphology is the theoretical link between morphological traits (e.g., size and shape of sperm components) and sperm function, especially swimming speed (reviewed by Humphries et al. 2008).

show abstract

“…Fatty acids, also stored in lipid globules at the middlepieces, have been shown to be the main source of energy for the spermatozoa of several sea urchin species (Mita, 1991;Mita et al, 1995). It has also been shown that fatty acids are the energy source for mammalian spermatozoa (Lardy and Phillips, 1941).…”

Section: Kolmer Et Almentioning

confidence: 98%

The Transcriptional and Translational Control of Diazepam Binding Inhibitor Expression in Rat Male Germ-Line Cells

Kolmer¹,

Pelto‐Huikko²,

Parvinen³

et al. 1997

DNA and Cell Biology

View full text Add to dashboard Cite

The diazepam binding inhibitor [DBI, also known as acyl-CoA-binding protein, (ACBP), or endozepine] is a 10-kD protein that has been suggested to be involved in the regulation of several biological processes such as acyl-CoA metabolism, steroidogenesis, insulin secretion, and gamma-aminobutyric acid type A (GABA(A))/benzodiazepine receptor modulation. DBI has been cloned from vertebrates, insects, plants, and yeasts. In mammals, DBI is expressed in almost all the tissues studied. Nevertheless, DBI expression is restricted to specific cell types. Here we have studied DBI gene expression in the germ-line cells of rat testis. The DBI gene was intensively transcribed in postmeiotic round spermatids from stages VI to VIII of the seminiferous epithelial cycle. A prominent, spermatid-specific upstream transcription initiation site was identified in addition to the multiple common transcriptional initiation sites found in the somatic tissues. However, no DBI protein was detected in round spermatids, suggesting that the DBI transcripts were translationally arrested. The DBI protein was detected in the late spermatogenic stages starting from elongating spermatids from step 18 (stage VI) onward. The DBI protein was also detected in mature spermatozoa and in ejaculated human sperms. The majority of DBI was located at the middle piece of the spermatozoons tail enriched with mitochondria. On the basis of this observation and the well-established role of DBI in acyl-CoA metabolism, we propose that DBI expression in spermatozoa reflects the usage of fatty acids as a primary energy source by spermatozoa. The biological function of DBI in spermatozoa could thus be related to the motility function of sperm.

show abstract

Endogenous substrate for energy metabolism and ultrastructural correlates in spermatozoa of the sea urchin Diadema setosum

Cited by 6 publications

References 24 publications

Comparative ultrastructure of spermatozoa from two regular and two irregular New Zealand echinoids

Comparative ultrastructure of spermatozoa from two regular and two irregular New Zealand echinoids

The Maintenance of Sperm Variability: Context-Dependent Selection on Sperm Morphology in a Broadcast Spawning Invertebrate

The Transcriptional and Translational Control of Diazepam Binding Inhibitor Expression in Rat Male Germ-Line Cells

Contact Info

Product

Resources

About