首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
Summary Mutants of E. coli, completely devoid of nitrite reductase activity with glucose or formate as donor were studied. Biochemical analysis indicates that they are simultaneously affected in nitrate reductase, nitrite reductase, fumarate reductase and hydrogenase activities as well as in cytochrome c552 biosynthesis. The use of an antiserum specific for nitrate reductase shows that the nitrate reductase protein is probably missing. A single mutation is responsible for this phenotype: the gene affected, nir R, is located close to tyr R i.e. at 29 min on the chromosomal map.Abbreviations BV Benzyl-Viologen - NTG N-methyl-N-nitro-N-nitrosoguanidine - NR nitrate reductase - NIR nitrite reductase - FR fumarate reductase - HYD hydrogenase - CYT c552 cytochrome c552  相似文献   

4.
5.
6.
7.
8.
9.
10.
11.
12.
D.Y.F(定向反馈—引导探索—反馈运用)是吉林市教育学院以科学方法为指导,以教育心理学为理论基础,在传统教学经验的基础上,设计的一种课堂教学类型。CAI(计算机辅助教学)则是以计算机为媒介,通过学生与计算机之间的交互作用来达到教学目的的一种现代化教...  相似文献   

13.
素质教育的目标是提高学生全面素质,使他们能够符合当前社会发展的要求,但目前的教学模式是以教师教为主(即注入式教学),无法充分发挥学生的主体作用。DYF(定向质疑———引导探索———反馈运用)是吉林市教育学院为了克服传统教学的弊端,变教师满堂灌为以...  相似文献   

14.
日本学者山村一雄.东市郎等人认为红色诺卡氏菌细胞壁骨架(Nocardia-Rubra-Cell Wall skeleton:N.R.CWS)的抗瘤效应极为明显,并认为其抗瘤效应均与巨噬细胞的激活密切相关。自1981年以来,我室观察到珊瑚色诺卡氏菌细胞壁、红色诺卡氏菌细胞壁骨架对小鼠移植瘤具有较强的抗瘤作用。为进一步探讨其抗瘤机制,对N.R.CWS活化的小鼠腹腔细胞(PEC)的吞噬、杀菌作用及细胞毒效应进行了探讨,现将实验结果总结如下。  相似文献   

15.
Bidwell著《植物生理学》已由刘富林同志译出,将由人民教育出版社出版,本文是崔澂同志为译本写的引言。  相似文献   

16.
17.
The volatile composition of needles from three F1 hard pine hybrids produced by the controlled hybridization and their parental species were researched with gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) in order to explore the utility of terpenes in hybrid identification (their differentiation from the parental species) as well as confirmation of hybridity. The analysed hybrids were: 1. Pinus nigra J. F. Arnold × Pinus sylvestris L. (= nisy), 2. P. nigra × Pinus densiflora Siebold et Zucc. (= nide) and 3. P. nigra × Pinus thunbergiana Franco (= nith). A total of 55 compounds were identified. All identified compounds were terpenes, except trans-2-hexenal.Three analysed F1 hybrids showed the same qualitative pattern of the needle volatile composition as their parental species. However, there were quantitative differences in several major terpenes. The volatile composition of the needles from the hybrids nisy were equally similar to both parents, the hybrids nide were more similar to the female parent (P. nigra), whereas the hybrids nith were more similar to the male parent (P. thunbergiana). According to the content of germacrene D, as the specific component of P. nigra (female parent of the three analysed F1 hybrids), all hybrids were intermediary in relation to the parental species. The content of Δ-3-carene (the specific component of P. sylvestris) in the hybrids nisy was also intermediary. The hybrids nide had a higher content of thunbergol (specific component of P. densiflora) than the other analysed hybrids. In view of the content of β-pinene, the specific component of P. thunbergiana, the hybrids nith were intermediary to the parental species and that content was considerably higher than in the other analysed hybrids. The intermediary quality of F1 hybrids for these specific components in relation to the parental species confirms their hybrid character.The needle volatile composition analysis as well as the previous morphometric analysis confirm the hybrid character of three F1 hybrids, whose female parent is P. nigra, and male parents are P. sylvestris, P. densiflora, i.e. P. thunbergiana.  相似文献   

18.
19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号