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41.
在中国应用垂直波束雷达监测褐飞虱和其他水稻害虫迁飞的可行性 总被引:1,自引:0,他引:1
J.R.Riley A.D.Smith D.R.Reynolds 《Entomologia Sinica》2003,10(1):1-19
近年来,可用于昆虫迁飞研究且可自动运行的垂直波束雷达(vertical-looking radar,VLR)的发展使得对迁飞性害虫的周年长期自动监测成为可能。本文提供了我们对能否将这种雷达应用于中国的褐飞虱和其他水稻害虫的监测与预测体系以改善其综合治理的可行性研究结果。以往的研究已经表明,这些害虫一般在300—2000m高度迁飞;而我们根据褐飞虱的雷达和射有效截面的计算结果表明,目前使用的3.2cm波长的VLR对褐飞虱个体目标的最大可检测高度仅约240m;虽然建造一部8.8mm波长的VLR即可覆盖褐飞虱迁飞高度的绝大部分,但其造价和维护费用均过于昂贵。为此,一个更可行的解决方案是,以3.2cm波长的VLR作为包括大多数水稻害虫在内的个体较大的迁飞性害虫的监测工具。 相似文献
42.
Sara Oldfield 《云南植物研究》2011,(1):I0003-I0003
At the first international symposium of Shanghai Chenshan Botanical Garden held on October11-14,2010,26representatives from13countries and 111 represents from69institutes and organizations of China came together for a program of presentations.The symposiumwas organized by Shanghai Landscaping Administrative Bureau,Shanghai Institutes for Biological Sciences 相似文献
43.
T Achstetter C Ehmann A Osaki D H Wolf 《The Journal of biological chemistry》1984,259(21):13344-13348
A new peptidase, which we call proteinase yscE, was purified from the yeast Saccharomyces cerevisiae. The enzyme cleaves the synthetic substrates Cbz-Gly-Gly-Leu-4-nitroanilide, Cbz-Ala-Ala-Leu-4-nitroanilide, and Suc-Phe-Leu-Phe-4-nitroanilide (Cbz and Suc are defined as benzyloxycarbonyl and succinyl, respectively) at the 4-nitroanilide bond and exhibits a slight activity against [3H]methylcasein. Optimum pH for cleavage of the chromogenic substrates is found to be in the range of 8.2 to 8.6. The purified enzyme has an apparent Stokes radius of Rs = 75.2 A as judged by gel chromatography and is composed of subunits. Mercurials were found to be strong inhibitors of the enzyme activity. 相似文献
44.
Tilman Achstetter Claudia Ehmann Dieter H. Wolf 《Biochemical and biophysical research communications》1982,109(2):341-347
A new aminopeptidase — aminopeptidase Co — has been detected in the yeast . The enzyme is only active in the presence of Co2+ions. Zn2+- and Mn2+ions are inhibitory. The enzyme activity is also inhibited by chelating agents. Of the p-nitroanilide derivatives tested only those containing basic amino acids are cleaved. 相似文献
45.
An investigation of the effect of radioactive labeling of DNA on excision repair in UV-irradiated human fibroblasts. 下载免费PDF全文
Previous studies on the kinetics of thymine dimer excision and unscheduled DNA synthesis in UV-irradiated human fibroblasts showed a significant discrepancy in these two parameters (Ehmann et al., 1978. Biophys. J. 22: 249). In the present study we have investigated the effect of the level of the radioactive isotope used for labeling cells on the kinetics of a parameter that directly measures thymine dimer excision. We find no significant differences in the kinetics of this parameter in cells lightly or heavily labeled with radioactive thymidine. 相似文献
46.
W C Ehmann A Dancis R Ferziger S Karpatkin 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1990,195(2):192-196
Three previous articles have reported a PLA1 antigen in the plasma of stored blood which is capable of binding to PLA1-negative platelets in the presence of divalent cations, rendering them PLA1 positive. Such a mechanism could explain the enigma of posttransfusion purpura (PTP), i.e., severe thrombocytopenia in a healthy subject with PLA1-negative platelets secondary to the infusion of blood containing PLA1-positive platelets. We find that the PLA1 antigen of stored blood is due to the presence of platelet fragments which can be removed by centrifugation and that divalent cation-chelating agents play no role in the apparent binding of these fragments to platelets. The apparent conversion of PLA1-negative platelets to the PLA1-positive phenotype by incubation with stored plasma from a PLA1-positive subject is due to the cosedimentation of platelet fragments with the platelets. No soluble PLA1 antigen was found in the plasma of five patients with acute posttransfusion purpura. 相似文献
47.
Substrate inhibition of chicken lactate dehydrogenase (EC 1.1.1.27) isoenzyme 5, was studied with the enzyme in the soluble phase and bound to muscle subcellular particulate structures. Inhibition studies were performed by incubating bound or soluble enzyme with NAD+ prior to measuring the reaction with a stopped-flow technique at 40 °C and a concentration of enzyme of 10?7m. The value of V for soluble lactate dehydrogenase was 610 nmoles per sec, and for the bound enzyme it was 262. km (pyruvate) values were similar for both enzymes. Under our experimental conditions, up to 73% inhibition of the soluble enzyme was observed. On the other hand, there was no detectable inhibition of bound lactate dehydrogenase. It is suggested that the resistance to substrate inhibition of bound lactate dehydrogenase may possibly be due to the prevention of dissociation of the enzyme into monomeric or other subunits because of attachment to the particulate structures. 相似文献
48.
海洋浮游藻类除通过吸收和释放分子与离子来改变其环境的化学成分外,还可通过细胞外表面一些酶的作用引起质膜外化学物质变化。在这方面,海洋浮游藻类一个主要的细胞外表面酶-碳酸酐酶(CA),在经胰蛋白酶处理从细胞质膜上释放出来后,仍保留其催化活性。当细胞外表面CA(简称细胞外CA)具活性时,可催化质膜外HCO_3~-与CO_2的相互转化,为Rubisco(磷酸核酮糖羧化酶)提供一稳定的CO_2流量环境,以维持正常的光合作用。 相似文献
49.
Trace element content in fingernails and hair of a nonindustrialized US control population 总被引:1,自引:0,他引:1
The concentrations of 17 elements in the nail and hair of 117 subjects from a nonindustrialized environment were determined
by instrumental neutron activation analysis (INAA). A new method of statistical treatment that allows for more meaningful
use of detection limit values was used to process the concentration data. Geometric means and standard errors are presented
for each element, along with a summary of the effects of age, sex, and treatment on the concentration of each element. For
nails, these data represent the first comprehensive study for several important elements. Correlations for each element between
hair and nail were determined. With few exceptions, concentrations of nonessential trace elements were positively correlated
in hair and nail, whereas concentrations of essential elements showed no correlations. The factors affecting concentrations
and control levels must be considered in studying alterations in disease states. 相似文献
50.
David COSTANTINI 《动物学报》2010,(6)
A strong focus of ecological research for several decades has been to understand the factors underlying the variation in animal life-histories. In recent times, ecological studies have begun to show that oxidative stress may represent another important modulator of competitive trade-offs among fitness traits or of positively integrated patterns of traits. Therefore, incorporating mechanisms underlying oxidative physiology into evolutionary ecology has the potential to help understand variation in life-histo... 相似文献