Author Keywords: Heat protection; cycloheximide; puromycin; putrescine; spermidine; spermine 相似文献
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21.
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
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Summary Citric acid was produced using Aspergillus niger immobilized on polyurethane foam in a bubble column reactor. Most of the adsorbed cells remained on the support and, as a result, high oxygen tension was maintained during the reactor operation. However, uncontrolled growth of the pellets made continuous reactor operation difficult. The citric acid productivity obtained from 15 vol.% foam particles containing immobilized cells was 0.135 g/l per hour. This productivity of immobilized cells was almost the same as that of free cells. The oxygen level dropped to half saturation in 5 days in the immobilized cell culture in contrast to 2 days in the free cell culture. 相似文献
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国产磨芋属的染色体核型报道(1) 总被引:4,自引:0,他引:4
本文报道了磨芋属(Amorphophallus Blume)六个种的染色体数目和核型,其中5个种属于首次报道。其核型公式如下: 1.滇磨芋 K(2n)=2x=26=26m.2.磨芋 K(2n)=2x=26=26m.3.攸落磨芋K(2n)=2x=26=22m(2SAT)+4sm.(2SAT).4.西盟磨芋 K(2n)=2x=26=20m+4sm+2st.5.勐海磨芋 K(2n)=2x=26=22m+4sm.6.白磨芋 K(2n)=2x=26=20m(2SAT)+6sm。 相似文献
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Nodal cuttings of white yam were induced to produce microtubers on a MS-revised medium supplemented with various concentrations of sucrose, 20 mgl–1 L-cysteine, 0.5 mgl–1 kinetin and 0.7% agar. The frequency of tuberization was affected by the daylength, which is optimal at 12 and 16 h of light depending on the sucrose concentration. The microtubers were planted in a seed bed and grown to maturity. The importance of in vitro tuberization of yam as a means of international germplasm distribution or exchange as well as for the propagation of planting material is discussed. 相似文献
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1. 1.|When Chinese hamster ovary cells are treated with cycloheximide (10 μg/ml) or puromycin (100 μg/ml) for 2 h before and during heating at 43°C for 3 h, there is protection from hyperthermic killing; i.e. the plating efficiency increases 2000-fold from 3.7 × 10−5 to (6–9) × 10−2.
2. 2.|The total intracellular levels of spermidine and spermine are not altered by the hyperthermic or drug treatments.
3. 3.|The small 30% decrease in intracellular putrescine observed after heating is not altered by drug treatment.
4. 4.|Heat protection by treatment with cycloheximide or puromycin cannot be attributed to changes in levels of total intracellular polyamines.
30.
Identification and characterization of a porcine parvovirus nonstructural polypeptide. 总被引:16,自引:9,他引:7 下载免费PDF全文
Sera from porcine parvovirus (PPV)-infected swine fetuses immunoprecipitated and 84- to 86-kilodalton polypeptide in addition to the A and B virion structural proteins. This polypeptide, designated NS-1, was present in PPV-infected cell lysates but not in purified virions. Partial proteolysis mapping revealed that NS-1 was not related to the A and B viral structural proteins. All three proteins in infected cells were phosphorylated at serine residues, and NS-1 also contained phosphothreonine. From pulse-labeling experiments with either 32Pi or [35S]methionine, NS-1 was found to first appear 5 to 7 h postinfection, whereas the viral structural polypeptides were first synthesized 9 to 11 h postinfection. Pulse-chase experiments revealed that NS-1 initially appeared as an 84-kilodalton protein and was subsequently structurally modified to forms of slower electrophoretic mobilities. The time of appearance of NS-1 after virus infection coincided with the initiation of viral DNA synthesis, suggesting that this polypeptide (and the modified forms thereof) may be involved in PPV replication. 相似文献