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11.
Jun‐Bo Luan Yong‐Ming Ruan Li Zhang Shu‐Sheng Liu 《Entomologia Experimentalis et Applicata》2008,129(3):316-324
The whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) is a species complex, and its systematic classification requires controlled crossing experiments among its genetic groups. Accurate information on pre‐copulation intervals, copulation frequencies, and initial frequency of egg fertilization of newly emerged adults is critical for designing procedures for collecting the virgin adults necessary for these experiments. In the literature, considerable variation is reported between B. tabaci populations, with respect to the length of the pre‐copulation interval and the initial frequency of egg fertilization. Here, we used a video‐recording method to observe continuously the copulation behaviour of the Mediterranean/Asia Minor/Africa (B biotype) and the Asia II (ZHJ1 biotype) groups of B. tabaci. We also recorded the initial frequency of egg fertilization, as determined by the sex of the progeny. When adults were caged in female–male pairs on leaves of cotton plants, the earliest copulation events occurred 2–6 h after emergence; at 12 h after emergence 56–84% of the females had copulated at least once, and nearly all (92–100%) had copulated at least once by 36 h after emergence. Both females and males copulated repeatedly. Approximately 80 and 20% of copulation events occurred during the photophase and scotophase, respectively. By 72 h post‐emergence, the females of the B and ZHJ1 biotypes had copulated on average 6.1 and 3.9 times, respectively. When adults were caged in groups on plants 1–13 h after emergence, 30–35% of the eggs deposited during this period were fertilized, and approximately 90% of females were fertilized by the end of the 13 h. Although timing of copulation differed in detail between the two genetic groups, the results demonstrate that B. tabaci adults can start to copulate as early as 2–6 h post‐emergence and the majority of females can become fertilized on the day that they emerge. 相似文献
12.
Reaction of nucleic acids with cis-diamminedichloroplatinum(II): interstrand cross-links 总被引:4,自引:0,他引:4
In the reaction of cis-diamminedichloroplatinum(II) (cis-DDP) with double-helical (dC-dG)4.(dC-dG)4 or (dC-dG)5.(dC-dG)5, intrastrand and interstrand cross-links between two guanine residues are formed. This is shown by gel electrophoresis in denaturing conditions of the reaction products and by high-performance liquid chromatography (HPLC) analysis of the products digested with nuclease P1. In the reaction of cis-DDP and poly(dG-dC).poly(dG-dC), at relatively low levels of platination, it is mainly interstrand cross-links between two guanine residues that are formed. This is shown by HPLC analysis of the nuclease P1 digest and by gel electrophoresis in denaturing and nondenaturing conditions of the platinated polymer after cleavage with the restriction enzyme HhaI. Moreover, the antibodies to platinated poly(dG-dC).poly(dG-dC) cross-react with the interstrand cross-linked (dC-dG)4 or (dC-dG)5 but not with the intrastrand cross-linked (dC-dG)4 or (dC-dG)5. These antibodies cross-react with platinated natural DNA. The amount of interstrand cross-links deduced from radioimmunoassays (0.5% of the total bound platinum) is lower than that (2%) deduced by gel electrophoresis in denaturing conditions of a platinated DNA restriction fragment. By gel electrophoresis, it is also shown that in vitro the isomer trans-DDP is more efficient in forming interstrand cross-links than cis-DDP. 相似文献
13.
Chemical probes of the conformation of DNA modified by cis-diamminedichloroplatinum(II) 总被引:15,自引:0,他引:15
The purpose of this work was to analyze at the nucleotide level the distortions induced by the binding of cis-diamminedichloroplatinum(II) (cis-DDP) to DNA by means of chemical probes. In order to test the chemical probes, experiments were first carried out on two platinated oligonucleotides. It has been verified by circular dichroism and gel electrophoresis that the binding of cis-DDP to an AG or to a GTG site within a double-stranded oligonucleotide distorts the double helix. The anomalously slow electrophoretic mobility of the multimers of the platinated and ligated oligomers strongly suggests that the platinated oligonucleotides are bent. The reactivity of the oligonucleotide platinated at the GTG site with chloroacetaldehyde, diethyl pyrocarbonate, and osmium tetraoxide, respectively, suggests a local denaturation of the double helix. The 5'G residue and the T residue within the adduct are no longer paired, while the 3'G residue is paired. The double helix is more distorted (but not denatured) at the 5' side of the adduct than at the 3' side. In the case of the oligonucleotide platinated at the AG site, the double helix is also more distorted at the 5' side of the adduct than at the 3' side. The G residue within the adduct is paired. The reactivities of the chemical probes with six platinated DNA restriction fragments show that even at a relatively high level of platination only a few base pairs are unpaired but the double helix is largely distorted. No local denaturation has been detected at the GG sites separated from the nearest GG or AG sites by at least three bases pairs.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
14.
Formation of a DNA monofunctional cis-platinum adduct cross-linking the intercalating drug N-methyl-2,7-diazapyrenium. 总被引:4,自引:3,他引:1
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Our purpose was to better understand the mutual influence of cis-diamminedichloroplatinum (II) (cis-DDP) and intercalating drugs in their interactions with DNA. The present study deals with the intercalating drug N-methyl-2,7-diazapyrenium (MDAP). Two sets of experiments have been performed. In one set, the reaction between cis-DDP and nucleic acid was carried out in the presence of MDAP. The main adduct is a guanine residue chelated by platinum to a MDAP residue. It has the same spectroscopic properties as the synthesized compound cis-[Pt (NH3)2 (N7-d-guanosine) (N7-MDAP)] , the structure of which has been determined by 1H NMR. This adduct was only formed with double-stranded nucleic acids which reveals the importance of DNA matrix in orienting favorably the reactants. In the second set of experiments, the triamine complex cis-[Pt(NH3)2 (MDAP)CI]++ was reacted with the nucleic acids. At molar ratios drug over nucleotide residue equal or less than 0.10, all the added triamine complexes bind by covalent coordination to double-stranded nucleic acids. With natural DNA, the major adduct is cis-[Pt(NH3)2(d-guanosine) (MDAP)] . Thus the same adduct is formed on one hand in the reaction between DNA, MDAP and cis-DDP and on the other hand in the reaction between the triamine complex and DNA. The triamine complex offers the possibility to study the biological role of the new adduct. 相似文献
15.
Protection of mice against Sendai virus pneumonia by non-neutralizing anti-F monoclonal antibodies 总被引:1,自引:0,他引:1
Y Mochizuki T de Ming T Hayashi M Itoh H Hotta M Homma 《Microbiology and immunology》1990,34(2):171-183
Nine monoclonal antibodies (MAbs) directed to F protein of Sendai virus were obtained and characterized for their protective ability against Sendai virus infection in mice. None of the MAbs showed hemagglutination-inhibition (HI), hemolysis-inhibition (HLI), or neutralization (NT) activities in vitro when assayed by standard methods. Some of the MAbs, however, showed complement-requiring NT (C-NT) and complement-requiring hemolysis (C-HL) activities when assayed in the presence of complement. Passive immunization experiments revealed that the MAbs with higher C-NT and C-HL activities showed protective activity against Sendai virus pneumonia in mice, and that some MAbs with IgG1 isotype having neither C-NT nor C-HL activity also showed the protective activity. Digestion of the MAbs with pepsin which split immunoglobulin molecules into F(ab')2 and Fc fragments greatly suppressed the protective activity. These results suggest that not only complement-mediated immunological responses such as immune virolysis but also antibody-dependent cellular cytotoxicity (ADCC) and/or immune phagocytosis, in which complement system is not necessarily involved, play an important role in the protection of mice from Sendai virus infection. 相似文献
16.
维西香茶菜的二萜成分 总被引:1,自引:0,他引:1
维西香茶菜Rabdosia weisiensis C. Y. Wu产云南西北部海拔2600米沟谷中,其化学成分的研究未见报道。从该植物叶的乙醚提取物中,分得两个二萜成分,一为已知成分trichorabdal A(2),一为新成分,命名为维西香茶菜甲素weisiensin A(1)。 维西香茶菜甲素weisiensin A(1),C_(26)H_(36)O_9,mp 298—300℃,其~(13)C NMR谱显示存在三个CH_3,三个CH_2,八个CH,三个四取代碳,三个Ac,二个烯碳和一个羰基 相似文献
17.
Gary K. Scott Peter L. Davies Ming H. Kao Garth L. Fletcher 《Journal of molecular evolution》1988,27(1):29-35
Summary The organization of antifreeze protein (AFP) genes in the yellowtail flounder was investigated by Southern blotting and the characterization of clones from a genomic library. This flounder, like the closely related winter flounder, has a set of 10–12 linked but irregularly spaced AFP genes. However, it lacks the tandemly amplified set of 20 such genes that are present in the winter flounder. DNA sequence analysis of a tandemly repeated gene from winter flounder showed that it can code for one of the two most abundant AFP components in the serum. Consistent with this higher AFP gene dosage, the peak serum AFP level in midwinter was 9 mg/ml in the winter flounder and only 4 mg/ml in the yellowtail flounder. A recent amplification of the AFP gene in the winter flounder lineage might be responsible for the higher serum AFP levels in this fish. This increase in gene dosage might have helped the winter flounder colonize the ice-laden, shallow-water niche that it currently occupies along the east coast of North America. Genomic Southern blotting of two other righteye flounders, the smooth flounder and the American plaice, illustrates another example of a differential amplification of AFP genes that correlates with a species' exposure to ice. 相似文献
18.
19.
Cibacron blue T_3GA与溴化氰活化的Sepharose 4B偶联后,产生一种能有效地分离有机磷水解酶的吸附剂。用0.15mol/L MgCl_2溶液从黄杆菌P3—2细胞抽提出的粗酶液通过柱层析分离,即可得到纯化8倍、酶活性回收率为269.4%的纯酶制品。该酶制品用凝胶电泳测是均一的。 相似文献
20.