Endogenous retroviruses

The genomes of vertebrates contain sequences that are similar to present-day exogenous retroviruses. Such sequences, called endogenous retroviruses (ERVs), have resulted from ancestral germ line infections by exogenous retroviruses which have thereafter been transmitted in a Mendelian fashion. By analogy to exogenous tumorigenic retroviruses, ERVs have been implicated in the pathogenesis of cancer. Cumulative evidence from animal models indicates that ERVs may participate in the process of malignant transformation or promote tumor growth, e.g. through insertional mutagenesis or via counteracting tumor immunosurveillance. Here, we review the role of ERVs in tumorigenesis with focus on human ERVs (HERVs) in human cancer. Although available data suggest a potential role of HERVs in human cancers, in particular germ cell tumors, the contributions of HERVs to human tumorigenesis warrant further elucidation. (Part of a Multi-author Review)     

Large-scale analysis of the yeast genome by transposon tagging and gene disruption

Economical methods by which gene function may be analysed on a genomic scale are relatively scarce. To fill this need, we have developed a transposon-tagging strategy for the genome-wide analysis of disruption phenotypes, gene expression and protein localization, and have applied this method to the large-scale analysis of gene function in the budding yeast Saccharomyces cerevisiae. Here we present the largest collection of defined yeast mutants ever generated within a single genetic background--a collection of over 11,000 strains, each carrying a transposon inserted within a region of the genome expressed during vegetative growth and/or sporulation. These insertions affect nearly 2,000 annotated genes, representing about one-third of the 6,200 predicted genes in the yeast genome. We have used this collection to determine disruption phenotypes for nearly 8,000 strains using 20 different growth conditions; the resulting data sets were clustered to identify groups of functionally related genes. We have also identified over 300 previously non-annotated open reading frames and analysed by indirect immunofluorescence over 1,300 transposon-tagged proteins. In total, our study encompasses over 260,000 data points, constituting the largest functional analysis of the yeast genome ever undertaken.     

Spring and winter records of the eastern pipistrelle ( Perimyotis subflavus ) in southeastern New Mexico

Eastern pipistrelles ( Perimyotis subflavus ) were first documented from South Dakota, western Texas, and New Mexico during recent years, suggesting that the distribution of this species is expanding westward across central parts of North America. In New Mexico, only 2 records of P. subflavus previously were known—one from summer and one from autumn. Here we report on 3 new records of P. subflavus from southeastern New Mexico, including the first 2 records from winter and the first record from spring. One individual in winter was observed hibernating in a cave in Chaves County. Our records and previous ones from autumn and summer suggest that this species is resident throughout the year in New Mexico.     

贝叶斯频谱估计在相移式目标定位中的应用

无线电波在传播过程中,如果遇到障碍物,会出现相位偏移,根据相位偏移量可以测定障碍物的位置。本文首先对能够反映相位偏移的Lissajous模式加以介绍,在实验中,根据目标物对天线发出的电波的相位偏移的影响,建立了一套用于目标探测的装置;然后通过分析天线模式,并根据电磁场的相关原理,建立起用于贝叶斯分析的模型方程;最后,运用贝叶斯频谱估计的方法对采集到的数据进行分析,估计出目标的位置。实验证明,由于在数据分析过程中运用了贝叶斯频谱估计这一先进的数据分析方法,因此该目标定位方法能够以较高的精度测定出目标的位置。通过我们进一步的努力,有望将它应用于地雷探测以及地下管道位置的测定中。