排序方式： 共有4条查询结果，搜索用时 15 毫秒
1
1.
The present study evaluated the effects of chilled storage and cryopreservation on sperm motion characteristics, antioxidant enzyme activities, and lipid peroxidation in the Pacific cod Gadus macrocephalus. Sperm motility and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (Gr), and lipid peroxidation (measured via malondialdehyde (MDA) content) were determined after the milt was stored at 4°C for 12 h, cryopreserved without cryoprotectant in 12% propylene glycol (PG), cryopreserved in 12% PG+0.1 mol/L trehalose, or cryopreserved in 12% PG spermatozoa but centrifuged to decant the supernatant prior to cryopreservation (only sperm cells were cryopreserved). After chilled storage or cryopreservation, the SOD, CAT and GPx activities were reduced in sperm cells and increased in seminal plasma in almost all treatments; sperm motility parameters were also decreased. However, the addition of trehalose into the cryoprotectant could significantly improve the postthaw sperm quality as revealed by the sperm average path velocity. This improvement might be attributed to the function of trehalose in scavenging reactive oxygen species. Chilled storage and cryopreservation had significant effects on sperm motion characteristics, antioxidant enzyme activities, and lipid peroxidation in the Pacific cod. 相似文献
2.
Turbots( Schophthalmus maximus), one of the most important economic marine flatfish species, fail to undergo final spawning and spermiation naturally under artificial farming conditions. In vertebrates, reproduction is regulated by the brain-pituitary-gonadal axis(BPG-axis), and gonadotropin releasing hormone(GnRH) is one of its key components. Therefore, to better understand the physiology of reproduction in the turbot, three of the genes encoding GnRH subtypes— sbGnRH, c GnRH-II and sGnRH —were cloned and sequenced by isolating the cDNA sequences. The localizations and patterns of expression of their mRNAs were also evaluated during seasonal gonadal development. All three mRNAs were expressed abundantly in the brain; sbGnRH and sGnRH mRNAs were also detected in the gonads and pituitary gland, and sbGnRH expression was much higher than that of sGnRH, indicating the critical role of sbGnRH in regulating the BPG-axis. Moreover, the brain expression patterns of sbGnRH and sGnRH mRNAs showed an increased trend during gonadal development, peaking in mature stages. This indicated the direct regulation of gonadal development by the GnRH system. In addition, c GnRH-II mRNA expression showed no significant variations, suggesting that c GnRH-II is not critically involved in the control of reproduction. Further, the mRNA abundances of the three GnRH forms in the breeding season were significantly higher than those in immature and post-breeding stages in all analyzed brain areas. Therefore, we propose that sbGnRH is the most important hormone for the regulation of reproduction in turbot via the BPG-axis. These results will help in better understanding the reproductive endocrine mechanisms of turbots and lay the groundwork for additional studies aimed at comparing the reproductive physiology of wild individuals with those raised under artificial conditions. 相似文献
3.
High temperature influences the homeostasis of fish.We investigated the effects of elevated temperature on tissues of Japanese flounder {Paralichthys olivaceus) by analyzing the histology and heat shock protein 70(hsp70) expression of fish reared in warm conditions.In this study,temperature was increased at l±0.5℃/day starting at 24±0.5℃,and was kept at that temperature for 5 days before the next rise.After raising temperature at the rate up to 32±0.5℃,tissue samples from midgut,spleen,stomach,liver,muscle,gill,heart,trunk kidney and brain were collected for histological analysis and mRNA assay.Almost all the tissues showed changes in morphological structure and hsp70 level at 32±0.5℃.Histological assessment of the tissues indicated that the gill had the most serious damage,including highly severe epithelial lifting and edema,curved tips and hyperemia at the ending of the lamellars,desquamation and necrosis.The next most severe damage was found in liver and kidney.The hsp70 levels in all the tissues first increased and then decreased.The gut,stomach,muscle,heart,and brain had the highest expressions in 6 h,whereas the spleen,liver,gill and kidney had the highest expressions in 2 h.Therefore,tissues with the most significant lesions(especially gill and liver) responded much earlier(2 h) in hsp70 expression than other tissues,and these tissues demonstrated the most marked histological disruption and elevated mRNA levels,making them ideal candidates for further studies on the thermal physiology of this species. 相似文献
4.
为研究孕激素在大菱鲆(Scophthalmus maximus)精原细胞增殖到减数分裂过程中的作用,以6~22月龄的大菱鲆精巢为材料,通过组织学方法和定量amh、sycp3基因确定精原细胞增殖期和减数分裂期的大菱鲆精巢发育过程。通过酶联免疫吸附技术(ELISA)检测6~22月龄雄性大菱鲆血清中的孕酮(P4)和17α,20β,双羟孕酮(DHP)含量变化,利用q RT-PCR技术和原位杂交技术检测孕酮核受体(pgr)和膜受体(m PRα)在不同组织和不同发育时期的表达情况。结果表明孕激素在精原细胞增殖期高表达,开始出现初级精母细胞时降低,在精子细胞数量增加时表达量再次升高,在精子细胞变态形成精子时降低。pgr在减数分裂初期定位于精巢中的sertoli细胞,在精原细胞增殖至减数分裂期表达量逐渐增加,出现精子后显著降低;m PRα在精原细胞增殖和初级精母细胞增加时表达量都很低,在精子细胞不断增加时显著增加。推测在精原细胞增殖和减数分裂阶段孕激素可能主要通过调节pgr的表达量来促进精巢发育,而在减数分裂II期pgr和m PRα都发挥作用,在精子细胞变态成熟时,主要是m PRα发挥作用。 相似文献
1