The effects ofpolychlorinated biphenyls (PCBs) on reproduction of adult cocks were studied by gavaging peanut oil or PCBs (Aroclor 1254, 50 mg/kg) once a week for six consecutive weeks. Physiological parameters were r...The effects ofpolychlorinated biphenyls (PCBs) on reproduction of adult cocks were studied by gavaging peanut oil or PCBs (Aroclor 1254, 50 mg/kg) once a week for six consecutive weeks. Physiological parameters were recorded and gonads were removed at the end of experiment for histological examination. The results showed that there was no significant difference between the control and treatment group in body weight, respiration rate, heart rate, body temperature, and the numbers of red and white blood cells. However, there was a marked decrease in the testicular weight and serum testosterone level after PCB treatment. Morphological studies manifested severe damage of the seminiferous tubules by PCB. The number of the germ cells at the different developmental stages was decreased and condensed nuclei were observed in most of these cells. This study revealed that the reproductive function of the adult cocks is sensitive to PCBs, which inhibited mainly spermatogenesis and testosterone secretion.展开更多
Biochemical changes of natural actomyosin from fresh pale, soft, exudative (PSE) and normal pork were studied,and the effects of different storage temperatures and different incubation temperature and times on sample ...Biochemical changes of natural actomyosin from fresh pale, soft, exudative (PSE) and normal pork were studied,and the effects of different storage temperatures and different incubation temperature and times on sample superprecipitation,total sulfhydryl (-SH) content, and ATP (adenosine triphosphate) sensitivity were investigated. The results demonstrated that ATPase activity and thermal stability of PSE actomyosin were lower than those of normal pork; and that PSE actomyosin had higher -SH content than that of normal pork at all incubation temperatures and times tested.展开更多
The fiber morphology variation of triploid clone of Populus tomentosa Carr. and the supposed harvesting age for the paper industry were investigated in this paper. The results shows that in the first few years, 2-4 ye...The fiber morphology variation of triploid clone of Populus tomentosa Carr. and the supposed harvesting age for the paper industry were investigated in this paper. The results shows that in the first few years, 2-4 years for example, the fiber length at breast high grows faster than it does in the later years. But the standard deviation of distribution in fiber length at breast high in mature wood is larger than in the young tree. The technologically harvestable age of triploid clone of Populus tomentosa Carr., BL304 could be 4-7 year old to meet the requirement for paper industry. The distribution of fiber length become concentrated within an annual ring as the tree grows. The test results also show that the cloned poplar has a small Runkel ratio value (less than 0.4, generally about 0.3), and this ratio increases slightly with the tree grows.展开更多
The effects of ultradry storage on the starch mobilization in maize (Zea mays L.) seed after aging were investigated. The results indicated that there were no significant differences in the content of ATP, starch, and...The effects of ultradry storage on the starch mobilization in maize (Zea mays L.) seed after aging were investigated. The results indicated that there were no significant differences in the content of ATP, starch, and soluble sugar, as well as the activity of amylase, between ultradried seeds and seeds stored at ?20 °C during germination. These results were consistent with the higher level of vigor of the ultradried seed. Sieve tube introduction of a fluorescence dye (carboxyl fluoresceindiacetate) and laser confocal microscopy were used to study the development of plasmodesmata in the ultradried seeds. The results indicated that plasmodesmata developed well in ultradried seeds. Fluorescence analysis also showed that the fluorescence intensity in the radicle of ultradried seeds was stronger than that in seeds with a higher moisture content. This suggests that ultradry treatment has no adverse effects on the seeds. After seed imbibition, cell orgaelles could be resumed. It is concluded that ultradry seed storage is beneficial for maintaining seed vigor and that starchy mobilization proceeds regularly during germination.展开更多
The “oxygen burst” phenomenon that appeared during the light-induction period of intact leaves could be monitored using a photoacoustic technique high time resolution. The relationship between oxygen bursts and dark...The “oxygen burst” phenomenon that appeared during the light-induction period of intact leaves could be monitored using a photoacoustic technique high time resolution. The relationship between oxygen bursts and dark-adapted time, far-red light pretreatment, photothermal signal, and chlorophyll a (Chl a) fluorescence kinetics were investigated in the present study. Using extraneous inhibitors or cofactors of electron transport, a modified vacuum-infiltration method was undertaken to locate directly the site at which oxygen bursts of intact leaves occurred. We found that the photothermal signal showed little evidence of oscillation during the light-induction period. The oxygen burst was resolved into two components if dark-adapted time lasted longer than 20 min. Methyl viologen (MV) or far-red light could not eliminate the first component, whereas formate-Na (pH 7.0,20 μmol/L) eliminated the first component but had no effect on the second one. Furthermore, the photochemical quenching, the electron transport rate of Chl a fluorescence, and the first component of the oxygen bursts approached lowest values simultaneously. This evidence indicates that the site at which the first component of oxygen bursts occurred was located between photo-system (PS)I and PSII (i.e. the PQ pool). The formate-Na experiment also showed a linkage between the first component and the S state of oxygen evolution at the donor side of PSII. Furthermore, elimination of the second component by far-red light and absorption of the second component by MV indicated that the site at which the second component of oxygen bursts may be located at the acceptor side of PSII.展开更多
In order to investigate the effects of different kinds of nuclear recipients from Kunming (KM) mouse on developmental potential of somatic nuclear transfer em- bryos, the enucleated MⅡ oocytes, enucleated zygotes and...In order to investigate the effects of different kinds of nuclear recipients from Kunming (KM) mouse on developmental potential of somatic nuclear transfer em- bryos, the enucleated MⅡ oocytes, enucleated zygotes and 2-cell blastomere were used to produce cloned mouse em-bryos. Using fibroblast deriving from C57/BL6 ear tissue as nuclear donor, we produced cloned embryos by transferring the fibroblast nuclei into enucleated KM mouse oocytes (sin-gle nuclear transfer, SNT), transferring pronuclei from the SNT embryos into enucleated KM zygotes (nuclear into zy-gote, NZ), and 2-cell blastomere nuclei from SNT embryos into enucleated KM mouse oocytes (nuclear into oocytes, NO); tetraploid embryos (tetraploid embryos, TE) were ob-tained by fusing two blastomeres, one is from the SNT cloned embryos, and the other from normal 2-cell KM mouse em-bryos. In group SNT, the cloned embryos could not develop beyond 8-cell stage and the rate of 8-cell stage is only 0.3%; in group NO, the reconstructed embryos could develop to morula stage, the rate of 8-cell stage was significantly greater than that of SNT group (P < 0.05); in group NZ, the devel-opment rate was further improved, and the reconstructed embryos could develop into blastocyst stage, the rate of blastocyst was 1.9%; in group TE, as high as 62.3% of the reconstructed embryos could develop into blastocyst. Results suggested that different nuclear recipients could significantly affect the developmental potential of cloned mouse embryos; KM MⅡ oocyte cytoplasm was not so effective as zygotes to reprogram the mouse somatic cell nuclei; serial nuclear transfer could improve the developmental potential of cloned mouse embryos.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 39970535) and Zhejiang (No. 302352) and Beijing Natural Science Foundation (No. 8000001) China
文摘The effects ofpolychlorinated biphenyls (PCBs) on reproduction of adult cocks were studied by gavaging peanut oil or PCBs (Aroclor 1254, 50 mg/kg) once a week for six consecutive weeks. Physiological parameters were recorded and gonads were removed at the end of experiment for histological examination. The results showed that there was no significant difference between the control and treatment group in body weight, respiration rate, heart rate, body temperature, and the numbers of red and white blood cells. However, there was a marked decrease in the testicular weight and serum testosterone level after PCB treatment. Morphological studies manifested severe damage of the seminiferous tubules by PCB. The number of the germ cells at the different developmental stages was decreased and condensed nuclei were observed in most of these cells. This study revealed that the reproductive function of the adult cocks is sensitive to PCBs, which inhibited mainly spermatogenesis and testosterone secretion.
基金Project (No. 200019) supported by the Natural Science Foundation of Zhejiang Province,China
文摘Biochemical changes of natural actomyosin from fresh pale, soft, exudative (PSE) and normal pork were studied,and the effects of different storage temperatures and different incubation temperature and times on sample superprecipitation,total sulfhydryl (-SH) content, and ATP (adenosine triphosphate) sensitivity were investigated. The results demonstrated that ATPase activity and thermal stability of PSE actomyosin were lower than those of normal pork; and that PSE actomyosin had higher -SH content than that of normal pork at all incubation temperatures and times tested.
文摘The fiber morphology variation of triploid clone of Populus tomentosa Carr. and the supposed harvesting age for the paper industry were investigated in this paper. The results shows that in the first few years, 2-4 years for example, the fiber length at breast high grows faster than it does in the later years. But the standard deviation of distribution in fiber length at breast high in mature wood is larger than in the young tree. The technologically harvestable age of triploid clone of Populus tomentosa Carr., BL304 could be 4-7 year old to meet the requirement for paper industry. The distribution of fiber length become concentrated within an annual ring as the tree grows. The test results also show that the cloned poplar has a small Runkel ratio value (less than 0.4, generally about 0.3), and this ratio increases slightly with the tree grows.
基金Basic Research and Development Plan of China,中国科学院资助项目,Life Science Special Fund of the Chinese Academy of Sciences by the Ministry of Finance
文摘The effects of ultradry storage on the starch mobilization in maize (Zea mays L.) seed after aging were investigated. The results indicated that there were no significant differences in the content of ATP, starch, and soluble sugar, as well as the activity of amylase, between ultradried seeds and seeds stored at ?20 °C during germination. These results were consistent with the higher level of vigor of the ultradried seed. Sieve tube introduction of a fluorescence dye (carboxyl fluoresceindiacetate) and laser confocal microscopy were used to study the development of plasmodesmata in the ultradried seeds. The results indicated that plasmodesmata developed well in ultradried seeds. Fluorescence analysis also showed that the fluorescence intensity in the radicle of ultradried seeds was stronger than that in seeds with a higher moisture content. This suggests that ultradry treatment has no adverse effects on the seeds. After seed imbibition, cell orgaelles could be resumed. It is concluded that ultradry seed storage is beneficial for maintaining seed vigor and that starchy mobilization proceeds regularly during germination.
文摘The “oxygen burst” phenomenon that appeared during the light-induction period of intact leaves could be monitored using a photoacoustic technique high time resolution. The relationship between oxygen bursts and dark-adapted time, far-red light pretreatment, photothermal signal, and chlorophyll a (Chl a) fluorescence kinetics were investigated in the present study. Using extraneous inhibitors or cofactors of electron transport, a modified vacuum-infiltration method was undertaken to locate directly the site at which oxygen bursts of intact leaves occurred. We found that the photothermal signal showed little evidence of oscillation during the light-induction period. The oxygen burst was resolved into two components if dark-adapted time lasted longer than 20 min. Methyl viologen (MV) or far-red light could not eliminate the first component, whereas formate-Na (pH 7.0,20 μmol/L) eliminated the first component but had no effect on the second one. Furthermore, the photochemical quenching, the electron transport rate of Chl a fluorescence, and the first component of the oxygen bursts approached lowest values simultaneously. This evidence indicates that the site at which the first component of oxygen bursts occurred was located between photo-system (PS)I and PSII (i.e. the PQ pool). The formate-Na experiment also showed a linkage between the first component and the S state of oxygen evolution at the donor side of PSII. Furthermore, elimination of the second component by far-red light and absorption of the second component by MV indicated that the site at which the second component of oxygen bursts may be located at the acceptor side of PSII.
基金the Climbing Project of the Ministry of Science and Technology of China (Grant No. 97021109-2) and the Major Project of Knowledge Innovation of the Chinese Academy of Sciences (Grant No. KSCX1-05-01)
文摘In order to investigate the effects of different kinds of nuclear recipients from Kunming (KM) mouse on developmental potential of somatic nuclear transfer em- bryos, the enucleated MⅡ oocytes, enucleated zygotes and 2-cell blastomere were used to produce cloned mouse em-bryos. Using fibroblast deriving from C57/BL6 ear tissue as nuclear donor, we produced cloned embryos by transferring the fibroblast nuclei into enucleated KM mouse oocytes (sin-gle nuclear transfer, SNT), transferring pronuclei from the SNT embryos into enucleated KM zygotes (nuclear into zy-gote, NZ), and 2-cell blastomere nuclei from SNT embryos into enucleated KM mouse oocytes (nuclear into oocytes, NO); tetraploid embryos (tetraploid embryos, TE) were ob-tained by fusing two blastomeres, one is from the SNT cloned embryos, and the other from normal 2-cell KM mouse em-bryos. In group SNT, the cloned embryos could not develop beyond 8-cell stage and the rate of 8-cell stage is only 0.3%; in group NO, the reconstructed embryos could develop to morula stage, the rate of 8-cell stage was significantly greater than that of SNT group (P < 0.05); in group NZ, the devel-opment rate was further improved, and the reconstructed embryos could develop into blastocyst stage, the rate of blastocyst was 1.9%; in group TE, as high as 62.3% of the reconstructed embryos could develop into blastocyst. Results suggested that different nuclear recipients could significantly affect the developmental potential of cloned mouse embryos; KM MⅡ oocyte cytoplasm was not so effective as zygotes to reprogram the mouse somatic cell nuclei; serial nuclear transfer could improve the developmental potential of cloned mouse embryos.