In order to determine the effect of foreign genes on a transgenic parasite,the pathogenicity and development in chickens of transgenic E.tenella strain TE1,which expresses yellow fluorescent protein (YFP) and dihydrof...In order to determine the effect of foreign genes on a transgenic parasite,the pathogenicity and development in chickens of transgenic E.tenella strain TE1,which expresses yellow fluorescent protein (YFP) and dihydrofolate reductase thymidylate synthase derived from Toxoplasma gondii(TgDHFR-TS), were compared with that of the parental strain BJ.Results indicated that the fecundity of the transgenic parasite(TE1) was reduced at least 4 times relative to that of the BJ strain.Low dosage of the TE1 strain induced less pathogenesis in chickens than did the BJ strain,but chickens inoculated with a higher dosage of TE1 oocysts displayed severe pathogenicity and mortality as did the BJ strain.In addition,trophozoites, the first generation and the second generation meronts and merozoites,microgamonts and macrogamonts of the transgenic parasite TE1 were seen by fluorescence microscopy.More interestingly,not all four sporonts in the sporulating transgenic oocysts express YFP.These findings suggest that the expression of YFP and TgDHFR-TS genes to some extent reduced pathogenicity and reproductive potential of transgenic E.tenella.Recombination between homologous or non-homologous chromosomes occurred during zygotic meiosis in E.tenella strain TE1.展开更多
In breeding season and non-breeding season, the effects of three kinds of progesterone plugs on estrous control in ewes were studied. Meanwhile, the advantages and the disadvantages of the progesterone plugs were anal...In breeding season and non-breeding season, the effects of three kinds of progesterone plugs on estrous control in ewes were studied. Meanwhile, the advantages and the disadvantages of the progesterone plugs were analyzed. The results showed that there were no significant difference among three progesterone plugs on modulating the ewes＇ estrus and pregnancy, and affecting estrous rate and fecundation rate （P〉0.05）. It was observed that the progesterone plug produced by Animal Husbandry Research Center of Heilongjiang Academy of Agricultural Sciences could modulate the ewes＇ estrus and pregnancy effectively, and the low cost and convenience in operation made it popularize in the reproducation of sheep widely.展开更多
【Aim】The oriental fruit moth,Grapholita molesta(Busck)(Lepidoptera:Tortricidae),is a worldwide fruit pest,causing serious loss to fruit productivity.Our study aims to explore the thermal tolerance and adaptability...【Aim】The oriental fruit moth,Grapholita molesta(Busck)(Lepidoptera:Tortricidae),is a worldwide fruit pest,causing serious loss to fruit productivity.Our study aims to explore the thermal tolerance and adaptability of G.molesta adults after exposure to short-term high temperature.【Methods】The survival rate of G.molesta adults exposed to various temperatures(36,38,40,42,44 and 46℃)for different time durations(0.5,1,2,4 and 8 h),and the effects of shortterm high temperature exposure(heat hardening at 38 or 40℃for 1 h)on their thermal tolerance,longevity,fecundity,and egg hatchability were investigated.【Results】The results showed that the survival rate of G.molesta adults was reduced with the increase of exposure duration to high temperature.The survival rate of G.molesta adults at 42℃was significantly improved after adults were subjected to heat hardening at 38℃or 42℃for 1 h(P〈0.05).After treatment at 41℃for 1 h,G.molesta adults were heat shocked,with longer life span and less fecundity.The further study confirmed that the male adults were greatly affected by high temperature,resulting in the reduction of eggs laid by female adults paired.Nevertheless,there was no remarkable difference in egg hatchability in different treatments though their parents underwent thermal stress.【Conclusion】These results suggest that high temperature exceeding 41℃for 1 h causes negative effects to G.molesta adults,but G.molesta adults have a relatively high thermal tolerance and the potential to adapt to high temperatures.展开更多
基金supported by the National High Technology Research and Development Program of China(Project No. 2006AA02Z458)the Doctor Startup Foundation of Henan University of Science and Technology(09001350)
文摘In order to determine the effect of foreign genes on a transgenic parasite,the pathogenicity and development in chickens of transgenic E.tenella strain TE1,which expresses yellow fluorescent protein (YFP) and dihydrofolate reductase thymidylate synthase derived from Toxoplasma gondii(TgDHFR-TS), were compared with that of the parental strain BJ.Results indicated that the fecundity of the transgenic parasite(TE1) was reduced at least 4 times relative to that of the BJ strain.Low dosage of the TE1 strain induced less pathogenesis in chickens than did the BJ strain,but chickens inoculated with a higher dosage of TE1 oocysts displayed severe pathogenicity and mortality as did the BJ strain.In addition,trophozoites, the first generation and the second generation meronts and merozoites,microgamonts and macrogamonts of the transgenic parasite TE1 were seen by fluorescence microscopy.More interestingly,not all four sporonts in the sporulating transgenic oocysts express YFP.These findings suggest that the expression of YFP and TgDHFR-TS genes to some extent reduced pathogenicity and reproductive potential of transgenic E.tenella.Recombination between homologous or non-homologous chromosomes occurred during zygotic meiosis in E.tenella strain TE1.
基金Supported by Heilongjiang Institute of Agricultural Sciences Youth Funded Projects
文摘In breeding season and non-breeding season, the effects of three kinds of progesterone plugs on estrous control in ewes were studied. Meanwhile, the advantages and the disadvantages of the progesterone plugs were analyzed. The results showed that there were no significant difference among three progesterone plugs on modulating the ewes＇ estrus and pregnancy, and affecting estrous rate and fecundation rate （P〉0.05）. It was observed that the progesterone plug produced by Animal Husbandry Research Center of Heilongjiang Academy of Agricultural Sciences could modulate the ewes＇ estrus and pregnancy effectively, and the low cost and convenience in operation made it popularize in the reproducation of sheep widely.
文摘【Aim】The oriental fruit moth,Grapholita molesta(Busck)(Lepidoptera:Tortricidae),is a worldwide fruit pest,causing serious loss to fruit productivity.Our study aims to explore the thermal tolerance and adaptability of G.molesta adults after exposure to short-term high temperature.【Methods】The survival rate of G.molesta adults exposed to various temperatures(36,38,40,42,44 and 46℃)for different time durations(0.5,1,2,4 and 8 h),and the effects of shortterm high temperature exposure(heat hardening at 38 or 40℃for 1 h)on their thermal tolerance,longevity,fecundity,and egg hatchability were investigated.【Results】The results showed that the survival rate of G.molesta adults was reduced with the increase of exposure duration to high temperature.The survival rate of G.molesta adults at 42℃was significantly improved after adults were subjected to heat hardening at 38℃or 42℃for 1 h(P〈0.05).After treatment at 41℃for 1 h,G.molesta adults were heat shocked,with longer life span and less fecundity.The further study confirmed that the male adults were greatly affected by high temperature,resulting in the reduction of eggs laid by female adults paired.Nevertheless,there was no remarkable difference in egg hatchability in different treatments though their parents underwent thermal stress.【Conclusion】These results suggest that high temperature exceeding 41℃for 1 h causes negative effects to G.molesta adults,but G.molesta adults have a relatively high thermal tolerance and the potential to adapt to high temperatures.
