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31.
1982年在四川省采集吸血蠓时,发现库蠓属(culicoides)两个新种。现记述如下。新种模式标本分别保藏于四川省成都铁路局中心卫生防疫站和中国科学院动物研究所。  相似文献   
32.
Recent work on oral narrative has emphasized differences in textual and performative approaches, which in turn has tended to widen the distinction between two fundamental categories of anthropological thought: structure and process. This paper argues that, at least for the interpretation of South American myth, an integrated approach is essential. After reviewing the epistemological basis of current problems in myth studies, the paper attempts a structural analysis of myths with the theme of a metamorphic conjugal union between human and nonhuman. Processual considerations are introduced in the form of syncretic myth, and the argument is advanced that there exist syncretic transformations of a structural nature. Identifying these provides the beginnings of a bridge between structure and process, and leads to an examination of the performative context of the subject myth. Other narrative genres, dealing with explicitly ethnic concepts, are implicated in the processual sequence of the telling and interpretation of the tale. The attempted synthesis of structure and process in narrative analysis leads to an engagement with two difficult problems: the relationship between ethnicity and kinship; and the transition from myth to history. [myth, structure, process, ethnicity, kinship]  相似文献   
33.
A numerical taxonomic study has been carried out to establish the relationship of group F to other biochemically similar organisms within the family Vibrionaceae. A total of 154 strains were examined including 59 of group F. Out of 114 characters determined for each strain 100 were used to compute average Euclidean distances between strains. Four methods of clustering were used, all of which gave very similar results.
Strains resembling Vibrio anguillarum fell into clusters corresponding to V. anguillarum, Beneckea nereida and a previously unrecognized group, phenon 5. Strains of the Aeromonas hydrophila/punctata group formed a heterogenous phenon within which certain subdivisions, perhaps artificial, could be discerned.
Group F strains all fell in one closely-knit cluster distinct from all the species of Vibrio, Aeromonas, Plesiomonas and Photobacteriwn studied. Group F strains could be divided into two biovars, I and II. Both biovars are present in aquatic, particularly estuarine, environments throughout the world but biovar I strains have also been isolated from humans with diarrhoea. It is concluded that group F is a synonym of group EF6 and that the strains within these groups should be classified in a new species named Vibrio fluvialis. The type strain is NCTC 11327.  相似文献   
34.
Pollen from chasmogamous flowers of Salpiglossis sinuata L. could not be induced to germinate in vitro unless stigmatal extract was applied to the culture medium. The substance that induces pollen germination in the stigmatal extract is water-soluble and heat-stable. Crosses could not be achieved between chasmogamous and cleistogamous flowers because of structural incompatibility. Pollinated pistils of chasmogamous flowers release a large amount of ethylene. The burst of ethylene release is due to an interaction between pollen tubes and stylar tissue and is directly proportional to the quantity of pollen placed on the stigma. Cleistogamous flower buds also produce a burst of ethylene at the time of pollination within the closed flower. The ethylene release may be a cause of reduced corolla development associated with cleistogamous flowers.  相似文献   
35.
The mechanism of action of antileishmanial compounds is poorly understood. Ultrastructural changes in Leishmania tropica within human macrophages exposed in vitro to Pentostam, pentamidine, amphotericin B, WR 6026, ketoconazole, and Formycin B were examined in these experiments. In Pentostam-treated cultures, some organisms exhibited diminished definition of mitochondrial and other membranes, while other organisms had completely disintegrated. Pentostam-exposed macrophages demonstrated loss of membrane definition in the absence of further alterations; it is therefore hypothesized that impaired macrophage membrane function may contribute towards the effect of this drug against macrophage-contained organisms. Leishmania parasites in pentamidine-treated cultures initially demonstrated swollen kinetoplasts and fragmentation of the kinetoplast DNA core. The initial observed effect of the other four drugs on the parasites was cytoplasmic condensation. These ultrastructural studies suggest that all five non-antimonial drugs may have different mechanisms of action than antimony (Pentostam) against Leishmania.  相似文献   
36.
Field-caged and open-plot populations of the aphid Sitobion avenae on winter wheat (cv. Maris Widgeon) were sampled approximately twice-weekly in the summer of 1978. Cage populations began at growth stage 10.2 (Feekes scale) (Zadoks, G. S. 52); they were removed by spraying with pirimicarb at growth stages 10.54 (71), 11.1–11.2 (77) and 11.2–11.3 (85) respectively. All cage populations reduced mean weight per grain but the effect per aphid unit was lowest in the population of longest duration. Although the aphid index in the open plots was higher than that in the early cage treatment, yield was unaffected. Cage infestations affected the breadmaking quality of the grain: percentage flour extraction was reduced and there was an increase in colour, nicotinic acid content and thiamine (vitamin B1) content of the flour; percentage nitrogen in the flour was unaffected but there was a reduction in baking value and in the high molecular weight glutenin content; infestation also reduced α-amylase activity. Different aspects of grain quality did not change in parallel with one another or with yield changes and thus damage thresholds will vary according to the yield/quality measure under consideration.  相似文献   
37.
ABSTRACT. The temporal changes in the size and pH of digestive vacuoles (DV) in Paramecium caudatum were reevaluated. Cells were pulsed briefly with polystyrene latex spheres or heat-killed yeast stained with three sulfonphthalein indicator dyes. Within 5 min of formation the intravacuolar pH declined from ~7 to 3. With the exception of a transient and early increase in vacuolar size, vacuole condensation occurred rapidly and paralleled the acidification so that vacuoles reached their lowest pH and minimal size simultaneously. Neutralization and expansion of vacuole size began when vacuoles were GT8 min old. No labeled vacuoles were defecated prior to 21 min after formation but almost all DV were defecated within 1 h so that the digestive cycle of individual vacuoles ranged from 21 to 60 min. Based on these size and pH changes, the presence of acid phosphatase activity, and membrane morphology, digestive vacuoles can be grouped into four stages of digestion. The DV-I are GT6 min old and undergo rapid condensation and acidification. The DV-II are between 4 to 10 min old and are the most condensed and acidic vacuoles. The DV-III range in age from 8 to ~20 min and include the expanding or expanded vacuoles that result from lysosomes fusing with DV-II. The DV-IV are GD21 min old, and since digestion is presumably completed, they can be defecated. The rise in intravacuolar pH that accompanies vacuole expansion suggests that lysosomes play a role in vacuole neutralization in addition to their degradative functions. The acidification and condensation processes in DV-I appear to be unrelated to lysosomal function, as no acid phosphaiase activity has been detected at this stage, but may be related to phagosomal functions important in killing food organisms, denaturing proteins prior to digestion, and preparing vacuole membrane for fusion with lysosomes.  相似文献   
38.
39.
太湖生态系统能量闭合特征及其影响因素   总被引:2,自引:0,他引:2  
王伟  申双和  刘寿东  张弥  肖薇  王咏薇  李旭辉 《生态学报》2017,37(18):5935-5950
地表能量不闭合不仅限制了涡度相关观测数据在陆面模型发展和验证等应用性研究中的价值,还给生态系统CO2源汇特征辨析带来不确定性。基于太湖避风港站2012年涡度相关通量、辐射、气象和水温梯度观测数据,分析了太湖能量闭合的多尺度(小时、日和月)时间变化特征,阐述了大气稳定度、摩擦风速和湖风对太湖能量闭合状况的影响。结果表明:太湖小时尺度的能量闭合度为0.59,且昼夜差异较小;日尺度的能量闭合度为0.73,在内陆水体观测结果中处于中等水平;月平均能量闭合度呈现冬季高、夏季低的季节变化特征;年平均时太湖仍有27%的能量不闭合。因摩擦风速减小,太湖能量闭合度在大气极不稳定条件下要比弱不稳定条件下结果低0.3;对于太湖这类大型浅水湖泊,其能量闭合度全天都受动力湍流交换强度制约,能量闭合度随摩擦风速增大而显著提高;虽然湖风发生使太湖小时尺度的能量闭合度降低了0.1,但其影响在日尺度上并不明显。  相似文献   
40.
从广西产眼镜王蛇(Ophiophagus hannah)毒腺中抽提总RNA,经mRNA纯化后构建眼镜王蛇毒腺cDNA文库。从所构建的cDNA文库中,随机筛选200个克隆测序,得到两个在进化上高度保守的基因:泛素融合蛋白基因(GenBank登录号为AF297036)和核糖体蛋白L30基因(GenBank登录号是AF297033)。前者cDNA的开放阅读框为387bp,后者为348bp。前者编码128个氨基酸残基组成的泛素融合蛋白前体;后者编码115个氨基酸残基组成的核糖体蛋白L30前体。由cDNA序列推导出的氨基酸序列分析表明,泛素融合蛋白前体包括N-末端的泛素结构域(76个氨基酸残基)和C-末端的核糖体蛋白L40结构域(52个氨基酸残基)。该蛋白为一高碱性蛋白,C末端含有一个“锌指”模式结构。与16个物种比较的结果表明,眼镜王蛇与脊椎动物的泛素融合蛋白氨基酸序列相似度较高,具有高度的保守性。  相似文献   
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