In mammals, sperm guidance in the oviduct appears essential for successful sperm arrival at the oocyte. Hitherto, three different potential sperm guidance mechanisms have been recognized： thermotaxis, rheotaxis, and ...In mammals, sperm guidance in the oviduct appears essential for successful sperm arrival at the oocyte. Hitherto, three different potential sperm guidance mechanisms have been recognized： thermotaxis, rheotaxis, and chemotaxis, each of them using specific stimuli - a temperature gradient, fluid flow, and a chemoattractant gradient, respectively. Here, we review sperm behavioral in these mechanisms and indicate commonalities and differences between them.展开更多
Background:The application of cryopreservation and artificial insemination technology have contributed to the advancement of animal reproduction.However,a substantial proportion of spermatozoa undergoes alterations an...Background:The application of cryopreservation and artificial insemination technology have contributed to the advancement of animal reproduction.However,a substantial proportion of spermatozoa undergoes alterations and loses their fertility during cryopreservation,rendering the frozen-thawed semen impractical for routine use.Cryopreservation is known to reduce sperm lifespan and fertility.Variation in cryosurvival of spermatozoa from different sires and even with the individual sire is common in artificial insemination(AI)centers.Our goal is to improve post-thawed semen quality by optimization of cryopreservation technique through sperm selection prior to cryopreservation process.Results:Our strategy of sperm selection based on rheotaxis and thermotaxis(SSRT)on macrosale in a rotating fluid flow demonstrated the ability to maintain the original pre-freezing structural integrity,viability and biological function related to fertilization competence.This strategy has a positive effect on the cryosurvival and fertilizing abilities of spermatozoa as supported by the improvement on pregnancy rate of Japanese Black heifers and Holstein repeat breeders.This technique protected further sublethal damage to bovine spermatozoa(higher%cryosurvival than the control)and resulted in the improvement of DNA integrity.Prefreeze selected spermatozoa demonstrated slower and controlled capacitation than unprocessed control which is thought to be related to sperm longevity and consequently to appropriate timing during in vivo fertilization.Conclusions:These results provide solid evidence that improvement of post-thawed semen quality by SSRT method is beneficial in terms of cryosurvival,longevity of post-thawed sperm,and optimization of in vivo fertilization,embryo development and calving as supported by the favorable results of field fertility study.展开更多
Zebrafish an emerging animal model for studies comparability with humans, good accessibility to the hearing utilize this animal model, methodologies need to be used to on auditory system. This model presents high org...Zebrafish an emerging animal model for studies comparability with humans, good accessibility to the hearing utilize this animal model, methodologies need to be used to on auditory system. This model presents high organ, and high throughput capacity. To better quantify the hearing function of the zebrafish. Zebrafish displays a series of innate and robust behavior related to its auditory function. Here, we reviewed the advantage of using zebrafish in auditory research and then introduced three behavioral tests, as follows： the startle response, the vestibular-ocular reflex, and rheotaxis. These tests are discussed in terms of their physiological characteristics, up-to-date technical development, and apparatus description. Test limitation and areas to improve are also introduced. Finally, we revealed the feasibility of these applications in zebrafish behavioral assessment and their potential in the high-throughput screening on hearing-related genes and drugs.展开更多
文摘In mammals, sperm guidance in the oviduct appears essential for successful sperm arrival at the oocyte. Hitherto, three different potential sperm guidance mechanisms have been recognized： thermotaxis, rheotaxis, and chemotaxis, each of them using specific stimuli - a temperature gradient, fluid flow, and a chemoattractant gradient, respectively. Here, we review sperm behavioral in these mechanisms and indicate commonalities and differences between them.
基金supported by the Ministry of Agriculture,Forestry and Fisheries,Japan(MAFF)under the project name“Development of technology for enhancement of livestock lifetime productivity by improving fertility through assisted reproduction”the JSPS KAKENHI(15H04585).
文摘Background:The application of cryopreservation and artificial insemination technology have contributed to the advancement of animal reproduction.However,a substantial proportion of spermatozoa undergoes alterations and loses their fertility during cryopreservation,rendering the frozen-thawed semen impractical for routine use.Cryopreservation is known to reduce sperm lifespan and fertility.Variation in cryosurvival of spermatozoa from different sires and even with the individual sire is common in artificial insemination(AI)centers.Our goal is to improve post-thawed semen quality by optimization of cryopreservation technique through sperm selection prior to cryopreservation process.Results:Our strategy of sperm selection based on rheotaxis and thermotaxis(SSRT)on macrosale in a rotating fluid flow demonstrated the ability to maintain the original pre-freezing structural integrity,viability and biological function related to fertilization competence.This strategy has a positive effect on the cryosurvival and fertilizing abilities of spermatozoa as supported by the improvement on pregnancy rate of Japanese Black heifers and Holstein repeat breeders.This technique protected further sublethal damage to bovine spermatozoa(higher%cryosurvival than the control)and resulted in the improvement of DNA integrity.Prefreeze selected spermatozoa demonstrated slower and controlled capacitation than unprocessed control which is thought to be related to sperm longevity and consequently to appropriate timing during in vivo fertilization.Conclusions:These results provide solid evidence that improvement of post-thawed semen quality by SSRT method is beneficial in terms of cryosurvival,longevity of post-thawed sperm,and optimization of in vivo fertilization,embryo development and calving as supported by the favorable results of field fertility study.
文摘Zebrafish an emerging animal model for studies comparability with humans, good accessibility to the hearing utilize this animal model, methodologies need to be used to on auditory system. This model presents high organ, and high throughput capacity. To better quantify the hearing function of the zebrafish. Zebrafish displays a series of innate and robust behavior related to its auditory function. Here, we reviewed the advantage of using zebrafish in auditory research and then introduced three behavioral tests, as follows： the startle response, the vestibular-ocular reflex, and rheotaxis. These tests are discussed in terms of their physiological characteristics, up-to-date technical development, and apparatus description. Test limitation and areas to improve are also introduced. Finally, we revealed the feasibility of these applications in zebrafish behavioral assessment and their potential in the high-throughput screening on hearing-related genes and drugs.
