The leaves of Bt (Bacillus thuringiensis) transgenic poplar (Populus nigra L.) and CpTI (Cowpea trypsin inhibitor) transgenic poplar ((P. tomentosa×P. bolleana)×P. Tomentosa) were taken to feed the 4th-5th-i...The leaves of Bt (Bacillus thuringiensis) transgenic poplar (Populus nigra L.) and CpTI (Cowpea trypsin inhibitor) transgenic poplar ((P. tomentosa×P. bolleana)×P. Tomentosa) were taken to feed the 4th-5th-instar larvae of American white moth (Hyphantria cunea (Drury)) for determination of the activities of the protective enzyme system inside larvae’s body. The physiological and biochemical effects of the transgenic poplars on the larvae were studied. The results showed that the two kinds of transgenic poplars had similar effects on the protective enzyme system in the midgut of larvae. The activities of superoxide dismutase, catalase, and peroxidase in midgut of the larvae increased gradually, reached the highest value at a certain time, and then decreased suddenly. For the larvae that were fed with the leaves of Bt transgenic poplar, the peak value of superoxide dismutase and catalase presented at the time of 24-h feeding, while the peak of peroxidase took place at the time of 12-h feeding. The activities of these protective enzymes for the larvae that were fed with leaves of CpTI transgenic poplar peaked 12 h later than that of those fed with leaves of Bt transgenic poplar. The comparison of activities of the protective enzymes was also carried out between the larvae with different levels of intoxication. It was found that the activities of protective enzyme of the seriously intoxicant larvae were higher than that of the lightly intoxicant larvae. This difference was more obvious in the group treated with CpTI transgenic poplar.展开更多
Chouioia cunea Yang is a natural enemy for many kinds of crop and forest pests, particularly for Hyphantria cunea Drary, which is an international quarantine pest. The experiment of rearing Chouioia cunea with Tussah ...Chouioia cunea Yang is a natural enemy for many kinds of crop and forest pests, particularly for Hyphantria cunea Drary, which is an international quarantine pest. The experiment of rearing Chouioia cunea with Tussah (Silkworm) pupa were carried out by 搕hree-cut method?and inoculating method. The results showed that three-cut method is effective way for breed-ing Chouioia cunea, with a parasitical rate of 95%. The biological characteristics and the life cycle of Chouioia cunea were ob-served and described and more hosts of Chouioia cunea were found. 揟hree-cut method?as a new technique of rearing Chouioia cunea has been put into practice.展开更多
With the research on and development of Genetically Modified Food （GMF）, people＇s attitude toward GMF may fall into two divergent categories, typical- ly represented by the United States（US） and the European Unio...With the research on and development of Genetically Modified Food （GMF）, people＇s attitude toward GMF may fall into two divergent categories, typical- ly represented by the United States（US） and the European Union（EU）, respectively. The former follows a ＂sound science principle＂ and firmly objects to the precautionary principle, namely a permissive policy of positive support of and voluntary labelling on GMF; while the latter adopts a cautiously precautionary principle, requiring mandatory labelling and traceability. From the standpoint of regulatory principles, together with corresponding supervisory measures and relevant provisions, this paper compared the execution of directives and provisions on GMF from the initial policies enacted by the US and EU to current situation combined with the track and analysis of latest polic ies issued.展开更多
British English and American English are regarded as the two major varieties of English in the world, and Canadian English is often treated as a variation of American English. The paper aims to identify the major phon...British English and American English are regarded as the two major varieties of English in the world, and Canadian English is often treated as a variation of American English. The paper aims to identify the major phonetic features of Canadian English by addressing its differences from British and American English based on a historical, demographical, and regional and dialectal analysis. Canadian English is a cultural phenomenon that has evolved on the basis of British English and under the heavy influence of American English. As a distinctive variety of English, Canadian English possesses its phonetic uniqueness. And in the context of globalization, Canadian English will remain subject to Americanization.展开更多
文摘The leaves of Bt (Bacillus thuringiensis) transgenic poplar (Populus nigra L.) and CpTI (Cowpea trypsin inhibitor) transgenic poplar ((P. tomentosa×P. bolleana)×P. Tomentosa) were taken to feed the 4th-5th-instar larvae of American white moth (Hyphantria cunea (Drury)) for determination of the activities of the protective enzyme system inside larvae’s body. The physiological and biochemical effects of the transgenic poplars on the larvae were studied. The results showed that the two kinds of transgenic poplars had similar effects on the protective enzyme system in the midgut of larvae. The activities of superoxide dismutase, catalase, and peroxidase in midgut of the larvae increased gradually, reached the highest value at a certain time, and then decreased suddenly. For the larvae that were fed with the leaves of Bt transgenic poplar, the peak value of superoxide dismutase and catalase presented at the time of 24-h feeding, while the peak of peroxidase took place at the time of 12-h feeding. The activities of these protective enzymes for the larvae that were fed with leaves of CpTI transgenic poplar peaked 12 h later than that of those fed with leaves of Bt transgenic poplar. The comparison of activities of the protective enzymes was also carried out between the larvae with different levels of intoxication. It was found that the activities of protective enzyme of the seriously intoxicant larvae were higher than that of the lightly intoxicant larvae. This difference was more obvious in the group treated with CpTI transgenic poplar.
文摘Chouioia cunea Yang is a natural enemy for many kinds of crop and forest pests, particularly for Hyphantria cunea Drary, which is an international quarantine pest. The experiment of rearing Chouioia cunea with Tussah (Silkworm) pupa were carried out by 搕hree-cut method?and inoculating method. The results showed that three-cut method is effective way for breed-ing Chouioia cunea, with a parasitical rate of 95%. The biological characteristics and the life cycle of Chouioia cunea were ob-served and described and more hosts of Chouioia cunea were found. 揟hree-cut method?as a new technique of rearing Chouioia cunea has been put into practice.
文摘With the research on and development of Genetically Modified Food （GMF）, people＇s attitude toward GMF may fall into two divergent categories, typical- ly represented by the United States（US） and the European Union（EU）, respectively. The former follows a ＂sound science principle＂ and firmly objects to the precautionary principle, namely a permissive policy of positive support of and voluntary labelling on GMF; while the latter adopts a cautiously precautionary principle, requiring mandatory labelling and traceability. From the standpoint of regulatory principles, together with corresponding supervisory measures and relevant provisions, this paper compared the execution of directives and provisions on GMF from the initial policies enacted by the US and EU to current situation combined with the track and analysis of latest polic ies issued.
文摘British English and American English are regarded as the two major varieties of English in the world, and Canadian English is often treated as a variation of American English. The paper aims to identify the major phonetic features of Canadian English by addressing its differences from British and American English based on a historical, demographical, and regional and dialectal analysis. Canadian English is a cultural phenomenon that has evolved on the basis of British English and under the heavy influence of American English. As a distinctive variety of English, Canadian English possesses its phonetic uniqueness. And in the context of globalization, Canadian English will remain subject to Americanization.
