Background Sperm migration by thermotaxis is a guidance mechanism that operates along the oviduct and it has proved to be a valid method for selecting spermatozoa with low DNA fragmentation(SDF)in mice,humans,and stal...Background Sperm migration by thermotaxis is a guidance mechanism that operates along the oviduct and it has proved to be a valid method for selecting spermatozoa with low DNA fragmentation(SDF)in mice,humans,and stallions.This study aimed to analyse if bull spermatozoa could be selected by thermotaxis and to assess their quality in terms of SDF as well as determine the presence of a specific sperm subpopulation based on sperm morphometry and assess their fertilizing capacity by ICSI.Methods We used frozen-thawed sperm from 6 bulls and sperm selection by thermotaxis was performed with TALP medium supplemented with 25 mmol/L of HEPES and 5 mmol/L of caffeine.In these conditions,sperm selection was achieved,obtaining a net thermotaxis of 3.6%.Subsequently,we analysed the SDF of the migrated and not-migrated spermatozoa using the neutral COMET assay,and we evaluated the size of the sperm head using Hemacolor■ staining with Motic Images Plus 3 software.Additionally,migrated and not-migrated spermatozoa by thermotaxis were used to fertilize bovine in vitro matured(IVM)oocytes by ICSI,a very inefficient procedure in cattle that is only successful when the oocyte is artificially activated.Results The results showed lower SDF(χ^(2),P<0.001,13.3%reduction,n=8)and lower head size parameters(length and width,P<0.01;and perimeter and area,P<0.001;n=4)in those spermatozoa migrated in comparison to those not-migrated.The distribution of sperm subpopulations structure varied between groups,highlighting cluster 2,characterized by spermatozoa with small head size,and high ellipticity and elongated heads,as the most abundant in the thermotaxis migrated group.When performed ICSI(without oocyte artificial activation)with the thermotactic sperm,the blastocyst rate was 32.2%±9.3%in the group microinjected with the thermotactic spermatozoa vs.8.3%±7.8%in the group of not-migrated sperm(χ^(2),P<0.05).Conclusion Our results showed that bull sperm selection by thermotaxis has a much higher DNA integrity,small and elongated head size parameters,and different sperm subpopulation structure than the not-selected spermatozoa.Additionally,we evidenced that thermotactic spermatozoa improve ICSI success rates.展开更多
Apart from the liver disruption, embryotoxicity and genotoxicity, microcystin (MC)-LR also could cause neurotoxicity. Nematode Caenorhabditis elegans was explored as a model to study the neurotoxicity. In the presen...Apart from the liver disruption, embryotoxicity and genotoxicity, microcystin (MC)-LR also could cause neurotoxicity. Nematode Caenorhabditis elegans was explored as a model to study the neurotoxicity. In the present study, we provided evidence to indicate the neurotoxicity on chemotaxis to NaCl and diacetyl, and thermotaxis from MC-LR exposure to C. elegans. As a result, higher concentrations of MC-LR caused significantly severe defects of chemotaxis to NaCl and diacetyl, and thermotaxis. The neurotoxicity on chemotaxis to NaCl and diacetyl, and thermotaxis from MC-LR exposure might be largely mediated by the damage on the corresponding sensory neurons (ASE, AWA, and AFD) and interneuron AIY. The expression levels ofche-1 and odr-7 were significantly decreased (P 〈 0.01) in animals exposed to MC-LR at concentrations lower than 10 μg/L, whereas the expression levels of ttx-1 and ttx-3 could be significantly (P 〈 0.01) lowered in animals even exposed to 1 μg/L of MC-LR. Moreover, both the chemotaxis to NaCl and diacetyl and the thermotaxis were more significantly reduced in MC-LR exposed mutants of che-1(p674), odr-7(ky4), ttx-1(p767), and ttx-3(ks5) than those in exposed wild-type N2 animals at the same concentrations.展开更多
It has been a scientific and technological problem in the field of microelectronics for several decades that the electrical method is used to measure the peak junction temperature of power transistors. Based on the ex...It has been a scientific and technological problem in the field of microelectronics for several decades that the electrical method is used to measure the peak junction temperature of power transistors. Based on the excessive thermotaxis effect of low current, a novel electrical measurement method of the peak junction temperature is presented in this paper. The method is called the thermal spectrum analysis method of transistors, simply designated TSA (thermal spectrum analysis method). Unlike the common method which uses a single measuring current, TSA uses multi-step currents to measure temperature-sensitive parameters. Based on the excessive thermotaxis effect of low current and the sub-transistor parallel model, the peak junction temperature and non-uniform property of junction temperature distribution are analyzed successfully.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
Here we investigated the possible roles of oxidative stress in the formation of decreased thermotaxis to cultivation temperature in lead (Pb)-exposed nematodes Caenorhabditis elagans. Exposure to Pb at the examined ...Here we investigated the possible roles of oxidative stress in the formation of decreased thermotaxis to cultivation temperature in lead (Pb)-exposed nematodes Caenorhabditis elagans. Exposure to Pb at the examined concentrations decreased thermotaxis behaviors, and induced severe deficits in the structural properties of AFD sensory neurons. Meanwhile, Pb exposure caused the induction of severe oxidative damage, reactive oxygen species (ROS) production, and mitochondrial dysfunction in young adults. Moreover, pre-treatment with the antioxidants dimethyl sulfoxide (DMSO), ascorbate and N-acetyl-L-cysteine (NAC), used to inhibit both the ROS elevation and the mitochondrial dysfunction caused by Pb exposure, at the L2-1arval stage prevented the induction of oxidative damage and the formation of severe deficits in thermotaxis and structural properties of AFD sensory neurons in Pb-exposed young adults. Therefore, the formation of oxidative stress caused by Pb exposure may be due to both the induction of ROS elevation and damage to mitochondrial function, and oxidative stress may play a key role in inducing the neurotoxic effects on the structures and function of AFD sensory neurons in Pb-exposed nematodes.展开更多
基金funded by the Spanish Ministry of Science and Innovation-MCIN (RTI2018-093548-B-100 and PID202M225070B-100 to A.Gutierrez-Adan and PID2019-1l1641 RB-100 to D.Rizos,funded by MCIN/AEI/10.13039/501100011033/and European Union"NextGeneration EU"/PRTR)supported by a Juan de la Cierva postdoctoral contract (FJC2019-040385-1)from the MCIN+1 种基金supported by a"Doctorados Industriales2018"fellowship of Comunidad de Madrid (IND2018/BIO-9610)supported by FPI scholarships from the MCIN (PRE2020-094452 and PRE2019-088813 respectively)。
文摘Background Sperm migration by thermotaxis is a guidance mechanism that operates along the oviduct and it has proved to be a valid method for selecting spermatozoa with low DNA fragmentation(SDF)in mice,humans,and stallions.This study aimed to analyse if bull spermatozoa could be selected by thermotaxis and to assess their quality in terms of SDF as well as determine the presence of a specific sperm subpopulation based on sperm morphometry and assess their fertilizing capacity by ICSI.Methods We used frozen-thawed sperm from 6 bulls and sperm selection by thermotaxis was performed with TALP medium supplemented with 25 mmol/L of HEPES and 5 mmol/L of caffeine.In these conditions,sperm selection was achieved,obtaining a net thermotaxis of 3.6%.Subsequently,we analysed the SDF of the migrated and not-migrated spermatozoa using the neutral COMET assay,and we evaluated the size of the sperm head using Hemacolor■ staining with Motic Images Plus 3 software.Additionally,migrated and not-migrated spermatozoa by thermotaxis were used to fertilize bovine in vitro matured(IVM)oocytes by ICSI,a very inefficient procedure in cattle that is only successful when the oocyte is artificially activated.Results The results showed lower SDF(χ^(2),P<0.001,13.3%reduction,n=8)and lower head size parameters(length and width,P<0.01;and perimeter and area,P<0.001;n=4)in those spermatozoa migrated in comparison to those not-migrated.The distribution of sperm subpopulations structure varied between groups,highlighting cluster 2,characterized by spermatozoa with small head size,and high ellipticity and elongated heads,as the most abundant in the thermotaxis migrated group.When performed ICSI(without oocyte artificial activation)with the thermotactic sperm,the blastocyst rate was 32.2%±9.3%in the group microinjected with the thermotactic spermatozoa vs.8.3%±7.8%in the group of not-migrated sperm(χ^(2),P<0.05).Conclusion Our results showed that bull sperm selection by thermotaxis has a much higher DNA integrity,small and elongated head size parameters,and different sperm subpopulation structure than the not-selected spermatozoa.Additionally,we evidenced that thermotactic spermatozoa improve ICSI success rates.
基金supported by the National Natural Sci- ence Foundation of China (No. 30771113, 30870810)and the Program for New Century Excellent Talents in Universityprovided by the Caenorhabditis Genetics Center (funded by the NIH, National Center for Foundation from Research Resource)
文摘Apart from the liver disruption, embryotoxicity and genotoxicity, microcystin (MC)-LR also could cause neurotoxicity. Nematode Caenorhabditis elegans was explored as a model to study the neurotoxicity. In the present study, we provided evidence to indicate the neurotoxicity on chemotaxis to NaCl and diacetyl, and thermotaxis from MC-LR exposure to C. elegans. As a result, higher concentrations of MC-LR caused significantly severe defects of chemotaxis to NaCl and diacetyl, and thermotaxis. The neurotoxicity on chemotaxis to NaCl and diacetyl, and thermotaxis from MC-LR exposure might be largely mediated by the damage on the corresponding sensory neurons (ASE, AWA, and AFD) and interneuron AIY. The expression levels ofche-1 and odr-7 were significantly decreased (P 〈 0.01) in animals exposed to MC-LR at concentrations lower than 10 μg/L, whereas the expression levels of ttx-1 and ttx-3 could be significantly (P 〈 0.01) lowered in animals even exposed to 1 μg/L of MC-LR. Moreover, both the chemotaxis to NaCl and diacetyl and the thermotaxis were more significantly reduced in MC-LR exposed mutants of che-1(p674), odr-7(ky4), ttx-1(p767), and ttx-3(ks5) than those in exposed wild-type N2 animals at the same concentrations.
基金Project supported by the National Natural Science Foundation of China (No.60476039)the Director Foundation of Institute of Microelectronics of Chinese Academy of Sciences (No.5408SA011001)
文摘It has been a scientific and technological problem in the field of microelectronics for several decades that the electrical method is used to measure the peak junction temperature of power transistors. Based on the excessive thermotaxis effect of low current, a novel electrical measurement method of the peak junction temperature is presented in this paper. The method is called the thermal spectrum analysis method of transistors, simply designated TSA (thermal spectrum analysis method). Unlike the common method which uses a single measuring current, TSA uses multi-step currents to measure temperature-sensitive parameters. Based on the excessive thermotaxis effect of low current and the sub-transistor parallel model, the peak junction temperature and non-uniform property of junction temperature distribution are analyzed successfully.
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.
基金supported by the National Basic Research Program (973) of China (No. 2011CB933404)and the National Natural Science Foundation of China (No.30870810,81172698)Some strains used were provided by Caenorhabditis Genetics Center (funded by the NIH National Center for Research Resource,USA)
文摘Here we investigated the possible roles of oxidative stress in the formation of decreased thermotaxis to cultivation temperature in lead (Pb)-exposed nematodes Caenorhabditis elagans. Exposure to Pb at the examined concentrations decreased thermotaxis behaviors, and induced severe deficits in the structural properties of AFD sensory neurons. Meanwhile, Pb exposure caused the induction of severe oxidative damage, reactive oxygen species (ROS) production, and mitochondrial dysfunction in young adults. Moreover, pre-treatment with the antioxidants dimethyl sulfoxide (DMSO), ascorbate and N-acetyl-L-cysteine (NAC), used to inhibit both the ROS elevation and the mitochondrial dysfunction caused by Pb exposure, at the L2-1arval stage prevented the induction of oxidative damage and the formation of severe deficits in thermotaxis and structural properties of AFD sensory neurons in Pb-exposed young adults. Therefore, the formation of oxidative stress caused by Pb exposure may be due to both the induction of ROS elevation and damage to mitochondrial function, and oxidative stress may play a key role in inducing the neurotoxic effects on the structures and function of AFD sensory neurons in Pb-exposed nematodes.