Motility, morphology, mitochondria and ATP content of diploid spermatozoa from sex-reversed clonal diploid and neo-tetraploid loach,Misgurnus anguillicaudatus

Abstract

Summary Diploid spermatozoa were obtained from sex‐reversed clonal diploid males and neo‐tetraploid which derived from normal diploid × natural tetraploid cross followed by the 2nd polar body release inhibition. The spermatozoa from sex‐reversed clonal diploid males exhibited a significant reduction in motility when compared with those from normal diploid and neo‐tetraploid males. Electron microscopy revealed that diploid spermatozoa from sex‐reversed clonal diploid and neo‐tetraploid males exhibited normal shape similar to haploid spermatozoa from normal diploid males, except for larger sperm‐head size and longer flagellum. Considering flow‐cytometric results, volume of mitochondrial mass per spermatozoon was also increased in proportion to the elevation of ploidy status from haploid to diploid sperm. Diploid spermatozoa from neo‐tetraploid increased the number of mitochondria and the ATP content, but those from sex‐reversed clonal diploid males did not show such results.

Comparison of spermatozoa parameters, fine structures, and energy‐related factors among tetraploid, hyper‐tetraploid, and hyper‐triploid loaches (Misgurnus anguillicaudatus)

“…As in our previous study (Zhao et al, ), hyper‐tetraploid loaches produced fertile hyper‐diploid spermatozoa. No differences in characteristics between diploid and hyper‐diploid spermatozoa were observed in the present study.…”

“…Evaluation of Motility, Concentration, and Viability of Spermatozoa Motility, concentration, and viability of spermatozoa were assessed using our previously described procedures for loach species (Zhao et al, 2012b). Total motility (%), progressive motility (%), and motility duration (sec) were obtained from video sequences as described by Zhao et al (2012b).…”

“…Evaluation of Motility, Concentration, and Viability of Spermatozoa Motility, concentration, and viability of spermatozoa were assessed using our previously described procedures for loach species (Zhao et al, 2012b). Total motility (%), progressive motility (%), and motility duration (sec) were obtained from video sequences as described by Zhao et al (2012b). To avoid overcrowding, sperm samples were diluted as follows: 1 mL of sample diluted by IS was pipetted onto a glass slide coated with 0.1% BSA solution and activation was performed by a 20-fold dilution in distilled water according to Yasui et al (2012).…”

“…The fine structure of spermatozoa was observed using scanning (SEM) and transmission electron microscopy (TEM), as in our previous study (Zhao et al, 2012b). Spermatozoa were fixed with 2.5% glutaraldehyde in 0.1 M phosphate buffer for 2 days at 4°C; washed repeatedly with the buffer, post-fixed in 4% osmium tetroxide for 2 hr at 4°C, washed repeatedly with the buffer, and dehydrated through an acetone series.…”

“…In a previous study, we compared parameters including motility, concentration, and viability; fine structures and morphological characteristics; and energy‐related factors such as mitochondrial mass per cell and ATP (adenosine tri‐phosphate) content between active diploid spermatozoa of neo‐tetraploid males and inactive diploid spermatozoa of sex‐reversed clonal diploid males to explain these differences (Zhao et al, ). Clonal diploid males were induced from a progeny of clonal females by the administration of 17‐α methyltestosterone during sex differentiation (Yoshikawa et al, , ), while neo‐tetraploids were produced by a cross between wild‐type diploid females (1n eggs) and natural tetraploid males (2n sperm) obtained from the market sample, followed by the inhibition of release of the second polar body (1n) (Arai et al, ; Zhang and Arai, ; Fujimoto et al, ).…”