The Genome Sequence of a Type ST239 Methicillin-Resistant Staphylococcus aureus Isolate from a Malaysian Hospital

We report the genome sequence of a healthcare-associated MRSA type ST239 clone isolated from a patient with septicemia in Malaysia. This clone typifies the characteristics of ST239 lineage, including resistance to multiple antibiotics and antiseptics.     

Characterization and developmental expression of a Drosophila ras oncogene.

We cloned a Drosophila melanogaster ras gene (Dmras64B) on the basis of its homology to the ras oncogen from Harvey murine sarcoma virus. This gene mapped at chromosomal position 64B on the left arm of the third chromosome. Sequencing of Dmras64B revealed extensive amino acid homology with the proteins encoded by the human and Saccharomyces cerevisiae ras genes. The coding region of the Drosophila gene is interrupted by two introns located in different positions with respect to its human counterpart. Dmras64B encodes three different RNAs (1.6, 2.1, and 2.6 kilobases long) that are constantly expressed throughout the development of the fly.     

Rho1 interacts with p120ctn and alpha-catenin,and regulates cadherin-based adherens junction components in Drosophila

Rho GTPases are important regulators of cellular behavior through their effects on processes such as cytoskeletal organization. Here we show interactions between Drosophila Rho1 and the adherens junction components alpha-catenin and p120(ctn). We find that while Rho1 protein is present throughout the cell, it accumulates apically, particularly at sites of cadherin-based adherens junctions. Cadherin and catenin localization is disrupted in Rho1 mutants, implicating Rho1 in their regulation. p120(ctn) has recently been suggested to inhibit Rho activity through an unknown mechanism. We find that Rho1 accumulates in response to lowered p120(ctn) activity. Significantly, we find that Rho1 binds directly to alpha-catenin and p120(ctn) in vitro, and these interactions map to distinct surface-exposed regions of the protein not previously assigned functions. In addition, we find that both alpha-catenin and p120(ctn) co-immunoprecipitate with Rho1-containing complexes from embryo lysates. Our observations suggest that alpha-catenin and p120(ctn) are key players in a mechanism of recruiting Rho1 to its sites of action.     

1981～2000年陕西省植被净初级生产力时空变化

为阐明陕西省植被净初级生产力(NPP)变化的整体状况,应用以遥感观测数据驱动的GLO-PEM模式模拟估计的NPP数据,对陕西省1981~2000年间的地表植被净初级生产力的空间分布及时间序列变化进行了综合分析.研究结果表明:(1)20年来,陕西省年NPP变化范围为687~858 g/(m2?a),平均值为749 g/(m2?a);(2)陕西省年平均NPP在波动中缓慢上升,NPP年增长幅度为3.248 2 g/(m2?a);(3)陕西省年平均NPP分布总体呈现从南到北递减的趋势,长城沿线风沙区NPP在200~400 g/(m2?a)之间,是陕西省NPP最低的地区;关中中东部NPP较高,大部在800 g/(m2?a)以上,NPP在1 200 g/(m2?a)以上的面积约占1/3,是全省NPP的高值区;(4)陕西省NPP基本不变(NPP变化百分率在-10%~10%之间)的面积占54.7%,NPP变化百分率增加10%以上的面积占40.5%,NPP变化百分率降低10%以下的面积仅占4.8%;(5)占陕西省总面积的77.3%的区域NPP变化不显著(P>0.05),NPP增加极显著(P<0.01)的区域占8.3%,增加显著(P<0.05)的区域占13.8%,NPP降低显著(P<0.05)和降低极显著(P<0.01)占0.7%.     

Time-resolved fluorescence resonance energy transfer studies of DNA bending in double-stranded oligonucleotides and in DNA-protein complexes

Time-resolved F?rster resonance energy transfer (trFRET) has been used to obtain interdye distance distributions. These distributions give the most probable distance as well as a parameter, sigma, that characterize the width of the distribution. This latter parameter contains information not only on the flexibility of the dyes tethered to macromolecules, but on the flexibility of the macromolecules. Both the most probable interdye distance as well as sigma provide insight into DNA static bending and DNA flexibility. Time-resolved fluorescence anisotropy and static anisotropy measurements can be combined to provide a measure of the cone angle within which the tethered dyes appear to wobble. When this motion is an order of magnitude faster than the average lifetime that characterizes transfer, an average value of the dipolar orientational parameter kappa2 can be calculated for various mutual dye orientations. The resulting kappa2 distribution is very much narrower than the limiting values of 0 and 4, allowing more precise distances and distance changes to be determined. Static and time-resolved fluorescence data can be combined to constrain the analyses of DNA-protein kinetics to provide thermodynamic parameters for binding and for conformational changes along a reaction coordinate. The parameter sigma can be used to model multiple DNA-protein complexes with varying DNA bend angles in a global fitting of trFRET data. Such a global fitting approach has shown how the range of bends in single base DNA variants, when bound by the TATA binding protein (TBP), can be understood in terms of two limiting forms. Time-resolved FRET, combined with steady-state FRET, can be used to show not only how osmolytes affect the binding of DNA to proteins, but also how DNA bending depends on osmolyte concentration in the DNA-protein complexes.     

Scene content selected by active vision

The primate visual system actively selects visual information from the environment for detailed processing through mechanisms of visual attention and saccadic eye movements. This study examines the statistical properties of the scene content selected by active vision. Eye movements were recorded while participants free-viewed digitized images of natural and artificial scenes. Fixation locations were determined for each image and image patches were extracted around the observed fixation locations. Measures of local contrast, local spatial correlation and spatial frequency content were calculated on the extracted image patches. Replicating previous results, local contrast was found to be greater at the points of fixation when compared to either the contrast for image patches extracted at random locations or at the observed fixation locations using an image-shuffled database. Contrary to some results and in agreement with other results in the literature, a significant decorrelation of image intensity is observed between the locations of fixation and other neighboring locations. A discussion and analysis of methodological techniques is given that provides an explanation for the discrepancy in results. The results of our analyses indicate that both the local contrast and correlation at the points of fixation are a function of image type and, furthermore, that the magnitude of these effects depend on the levels of contrast and correlation present overall in the images. Finally, the largest effect sizes in local contrast and correlation are found at distances of approximately 1 deg of visual angle, which agrees well with measures of optimal spatial scale selectivity in the visual periphery where visual information for potential saccade targets is processed.