Heritable and inducible genetic interference by double-stranded RNA encoded by transgenes

Double-stranded RNA interference (RNAi) is an effective method for disrupting expression of specific genes in Caenorhabditis elegans and other organisms. Applications of this reverse-genetics tool, however, are somewhat restricted in nematodes because introduced dsRNA is not stably inherited. Another difficulty is that RNAi disruption of late-acting genes has been generally less consistent than that of embryonically expressed genes, perhaps because the concentration of dsRNA becomes lower as cellular division proceeds or as developmental time advances. In particular, some neuronally expressed genes appear refractory to dsRNA-mediated interference. We sought to extend the applicability of RNAi by in vivo expression of heritable inverted-repeat (IR) genes. We assayed the efficacy of in vivo-driven RNAi in three situations for which heritable, inducible RNAi would be advantageous: (i) production of large numbers of animals deficient for gene activities required for viability or reproduction; (ii) generation of large populations of phenocopy mutants for biochemical analysis; and (iii) effective gene inactivation in the nervous system. We report that heritable IR genes confer potent and specific gene inactivation for each of these applications. We suggest that a similar strategy might be used to test for dsRNA interference effects in higher organisms in which it is feasible to construct transgenic animals, but impossible to directly or transiently introduce high concentrations of dsRNA.     

Mutations in the gene encoding pejvakin, a newly identified protein of the afferent auditory pathway, cause DFNB59 auditory neuropathy

Auditory neuropathy is a particular type of hearing impairment in which neural transmission of the auditory signal is impaired, while cochlear outer hair cells remain functional. Here we report on DFNB59, a newly identified gene on chromosome 2q31.1-q31.3 mutated in four families segregating autosomal recessive auditory neuropathy. DFNB59 encodes pejvakin, a 352-residue protein. Pejvakin is a paralog of DFNA5, a protein of unknown function also involved in deafness. By immunohistofluorescence, pejvakin is detected in the cell bodies of neurons of the afferent auditory pathway. Furthermore, Dfnb59 knock-in mice, homozygous for the R183W variant identified in one DFNB59 family, show abnormal auditory brainstem responses indicative of neuronal dysfunction along the auditory pathway. Unlike previously described sensorineural deafness genes, all of which underlie cochlear cell pathologies, DFNB59 is the first human gene implicated in nonsyndromic deafness due to a neuronal defect.     

从枫树图腾看苗族建筑中的生命伦理思想

建筑与图腾有着紧密的联系,建筑是传承图腾文化的载体.枫树作为苗族的民族图腾,其文化底蕴是十分丰厚的,这一文化通过建筑得到了广泛的体现.其蕴含的生命伦理思想具有民族的特色,主要表现为生命自然观和生命神圣观.     

Web GIS技术及其实现方法

基于网上地理信息发布系统,介绍了ＧＩＳ的新兴技术－－ＷｅｂＧＩＳ技术的概念,以及与传统ＧＩＳ技术的不同之处和它的特点,并以ＥＳＲＩ公司的产品为例,说细论述了ＷｅｂＧＩＳ技术的两种不同的实现方法。     

关于转基因食品的争论

植物的遗传操作目前在英国产生了极大的轰动效应,可谓是议论纷纷,褒贬不一。超级市场上的新型食品丰富多彩,满足了消费者的需求,感谢现代集约型农业所提供的这一切。但富余也同时带有自身的问题,这不仅是技术变化的加速。物质的丰富,寿命的延长,都对无风险环境提出了要求。和世纪初相比,当今的西方人更讲究健康食品;所以对用新法生产的同种食品,态度冷淡;尤其是对那些被怀疑有风险的食品,即使对健康稍有涉嫌,公众也不愿轻易接受。关于超级杂草fo］题英国医学会和环境保护人员,否定了对草甘脚含有抗性的GM油菜;认为一种特异…     

形变双奇核1944Au中的强耦合带

利用重离子融合蒸发反应159Tb（29Si,4nγ）194Au布居了形变双奇核184Au的高自旋态,用GASP探测器阵列进行了在束γ实验测量．通过对实验数据的深入分析,新发现了一条可归属于184Au核的强耦合转动带．基于对转动带有效K值的分析以及从实验数据中提取出的带内B（M1）／B（E2）值与理论计算值的比较,建议了转动带的准粒子组态和能级的自旋宇称值．     

Adelfa： a futuristic biodiesel fuel for DI diesel engines： a comparative experimental investigation

Biodiesel fuel is found to be a promising alter- native for the petroleum diesel based on the results published by the researchers for a decade. Biodiesel fuel is renewable and non degradable fuel. Many countries use biodiesel fuel for automotives to meet the crisis due to the depletion of the petroleum fuel and to meet the stringent emission norms. Various researches have been carried out with different bio- diesel fuels with vegetable oil as the source and appreciable results were reported. Few biodiesel fuels which have been already tested are Jatropha, Pongamia, Mahua, neem, cotton seed, etc. In this experimental work, Adelfa biodiesel blend is used as the test fuel. The emission and performance charac- teristics were compared with three other different biodiesel fuel blends. Appreciable results imply that Adelfa biodiesel （Nerium oil methyl ester） can be a futuristic biodiesel fuel, which has a good compatibility with the direct injection （DI） diesel engine without any major modification. Moreover, Adelfa can be cultivated in a non agricultural land with fewer sources of water. It is widely spread over all major countries of Asia. Experimental investigations have been carried out on a single cylinder DI diesel engine with standard engine speci- fications. In this experimental work, various Adelfa biodiesel blends is compared with reference fuel （diesel） to choose the best blend which gives a closer performance to diesel. The comparative analysis with other biodiesel fuels has also been done and results have been discussed.     

SLAC1 is required for plant guard cell S-type anion channel function in stomatal signalling

Stomatal pores, formed by two surrounding guard cells in the epidermis of plant leaves, allow influx of atmospheric carbon dioxide in exchange for transpirational water loss. Stomata also restrict the entry of ozone--an important air pollutant that has an increasingly negative impact on crop yields, and thus global carbon fixation and climate change. The aperture of stomatal pores is regulated by the transport of osmotically active ions and metabolites across guard cell membranes. Despite the vital role of guard cells in controlling plant water loss, ozone sensitivity and CO2 supply, the genes encoding some of the main regulators of stomatal movements remain unknown. It has been proposed that guard cell anion channels function as important regulators of stomatal closure and are essential in mediating stomatal responses to physiological and stress stimuli. However, the genes encoding membrane proteins that mediate guard cell anion efflux have not yet been identified. Here we report the mapping and characterization of an ozone-sensitive Arabidopsis thaliana mutant, slac1. We show that SLAC1 (SLOW ANION CHANNEL-ASSOCIATED 1) is preferentially expressed in guard cells and encodes a distant homologue of fungal and bacterial dicarboxylate/malic acid transport proteins. The plasma membrane protein SLAC1 is essential for stomatal closure in response to CO2, abscisic acid, ozone, light/dark transitions, humidity change, calcium ions, hydrogen peroxide and nitric oxide. Mutations in SLAC1 impair slow (S-type) anion channel currents that are activated by cytosolic Ca2+ and abscisic acid, but do not affect rapid (R-type) anion channel currents or Ca2+ channel function. A low homology of SLAC1 to bacterial and fungal organic acid transport proteins, and the permeability of S-type anion channels to malate suggest a vital role for SLAC1 in the function of S-type anion channels.     

高层钢结构设计中几点问题的探讨

章介绍了钢结构在我国的运用和钢结构的优越性能；探讨了高层钢结构在设计方法、设计指标(高宽比限制，层间变形限值)、抗风设计(风振系数、人体舒适度等)、抗震设计、抗火设计中存在的一些问题以及迫切需要研究的方面。