Human T cell leukemia viruses use a receptor determined by human chromosome 17

Human T cell leukemia viruses (HTLV-I and HTLV-II) can infect many cell types in vitro. HTLV-I and HTLV-II use the same cell surface receptor, as shown by interference with syncytium formation and with infection by vesicular stomatitis virus (VSV) pseudotypes bearing the HTLV envelope glycoproteins. Human-mouse somatic cell hybrids were used to determine which human chromosome was required to confer susceptibility to VSV(HTLV) infection. The only human chromosome common to all susceptible cell hybrids was chromosome 17, and the receptor gene was localized to 17cen-qter. Antibodies to surface antigens known to be determined by genes on 17q did not block the HTLV receptor.     

Prediction of a crystallization pathway for Z-DNA hexanucleotides

Crystallization of macromolecules for structural studies has long been a hit-or-miss process. The crystallization of hexanucleotides as Z-DNA was studied, and it was shown that the cation concentration for crystal formation could be predicted from solvation free energy (SFE) calculations. Solution studies on the conformation and solubilities of the hexanucleotides showed that a critical concentration of the DNA in the Z-conformation must be present in solution to effect crystallization. The SFE calculations therefore predict the propensity of the hexanucleotides to adopt the left-handed conformation and the driving force required to reach this critical concentration relative to the intrinsic solubility of Z-DNA for crystallization.     

Definition of a bacterial type IV secretion pathway for a DNA substrate

Bacteria use conjugation systems, a subfamily of the type IV secretion systems, to transfer DNA to recipient cells. Despite 50 years of research, the architecture and mechanism of action of the channel mediating DNA transfer across the bacterial cell envelope remains obscure. By use of a sensitive, quantifiable assay termed transfer DNA immunoprecipitation (TrIP), we identify contacts between a DNA substrate (T-DNA) and 6 of 12 components of the VirB/D4 conjugation system of the phytopathogen Agrobacterium tumefaciens. Our results define the translocation pathway for a DNA substrate through a bacterial conjugation machine, specifying the contributions of each subunit of the secretory apparatus to substrate passage.     

Biomarker evidence for a major preservation pathway of sedimentary organic carbon

Hydrogenation processes leading from biomolecules to fossil biomarkers in anoxic sediments are crucial for the preservation of organic matter. However, these processes are still poorly understood. The present identification of several reduced carotenoids in recent sediments attests that these processes operate at the earliest stages of diagenesis without structural or stereochemical specificity, implying a nonbiological reduction pathway. Sulfur species (e.g., H2S) are the hydrogen donors involved in such reduction, as demonstrated with laboratory experiments. These reactions allow the preservation of abundant organic carbon in the rock record.     

Archaeal type III RuBisCOs function in a pathway for AMP metabolism

The type III ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCO) present in the archaeon Thermococcus kodakaraensis was found to participate in adenosine 5'-monophosphate (AMP) metabolism, a role that is distinct from that of classical RuBisCOs of the Calvin-Benson-Bassham cycle. Genes annotated as thymidine phosphorylase (deoA) and eucaryal translation initiation factor 2B (e2b2) were found to encode AMP phosphorylase and ribose-1,5-bisphosphate isomerase, respectively. These enzymes supplied the RuBisCO substrate, ribulose-1,5-bisphosphate, from AMP and phosphate. Archaea with type III RuBisCOs all harbor both DeoA and the corresponding E2b2 homologs. In this pathway, adenine was released from AMP and the phosphoribose moiety entered central-carbon metabolism.     

Direct evidence for a parietal-frontal pathway subserving spatial awareness in humans

Intraoperative electrical stimulation, which temporarily inactivates restricted regions during brain surgery, can map cognitive functions in humans with spatiotemporal resolution unmatched by other methods. Using this technique, we found that stimulation of the right inferior parietal lobule or the caudal superior temporal gyrus, but not of its rostral portion, determined rightward deviations on line bisection. However, the strongest shifts occurred with subcortical stimulation. Fiber tracking identified the stimulated site as a section of the superior occipitofrontal fasciculus, a poorly known parietal-frontal pathway. These findings suggest that parietal-frontal communication is necessary for the symmetrical processing of the visual scene.     

风干表土对土壤水分蒸发阻力研究

引入土壤表面阻力概念来说明土壤水分蒸发过程,提出了实验室测定其大小的整套试验方法。在此基础上,对土壤表面阻力与蒸发、影响蒸发的主要因子的关系进行了分析研究。结果表明,土壤表面阻力总趋势是随蒸发时间的延长和累积蒸发量的增加而增大,但这种关系有可能被土壤蒸发面和大气间水汽压差的改变所打破,土壤蒸发面和大气间水汽压差是决定土壤表面阻力的主要因素之一。同时,还对土壤表面阻力与蒸发时间的关系、与蒸发时间及土壤蒸发面和大气间水汽压差的关系进行了模拟,结果后一种比前一种模拟更符合实际。     

Design of a surface alloy catalyst for steam reforming

Detailed studies of elementary chemical processes on well-characterized single crystal surfaces have contributed substantially to the understanding of heterogeneous catalysis. Insight into the structure of surface alloys combined with an understanding of the relation between the surface composition and reactivity is shown to lead directly to new ideas for catalyst design. The feasibility of such an approach is illustrated by the synthesis, characterization, and tests of a high-surface area gold-nickel catalyst for steam reforming.     

示范引领促发展 以点带面共提升

邵鹏飞名师工作室系无锡市教育局授牌成立的名师工作室,成立于2013 年3 月,在省 特级教师邵鹏飞老师的带领下,汇聚成员力量,凝聚团队合力,大幅提升了团队的教学水平,有 效改善了本专业的教学环境,为培养“现代班组长”型人才作出了贡献。本工作室的工作宗旨是 “示范引领促发展,以点带面共提升”。     

Dehalogenation: a novel pathway for the anaerobic biodegradation of haloaromatic compounds

Microorganisms of lake sediment and sewage sludge anaerobically metabolized halobenzoates by a novel pathway. The primary degradative event was loss of the aryl halide without the alteration of the aromatic ring. Dehalogenation required strict anaerobic conditions and depended on the halogen and position, but not the number of halogen substituents. A stable methanogenic bacterial consortium was enriched from sludge and found capable of dehalogenating and often mineralizing a variety of halobenzoates to CH(4) and CO(2). The results suggest that reductive dehalogenation of aromatics could be important in removal of some chlorinated xenobiotics from the environment.     

Human detection for a robot tractor using omni-directional stereo vision

It is critical to detect and identify obstacles for safe operation of robot tractors. This study focused on human detection using an omni-directional stereo vision (OSV). The Lucas–Kanade optical flow detection method was used to detect human in a panoramic image. A 3D panoramic image that was reconstructed from stereo rectified images using the sum of squared differences (SSDs) method was used to locate the position of a human. To evaluate the performance of the developed human detection method, two RTK-GPSs were used to investigate the accuracy of the detection method under stationary and motion conditions of a robot tractor. The results of field experiments indicated that a human could be detected successfully under both given conditions in the daytime. The RMS error of measured distance was less than half a meter compared with the reference distance measured by the RTK-GPSs.     

研究生教育人力资本投资的制度导向

作为知识经济时代重要投资项目,研究生教育人力资本投资得到全社会越来越多的关注和重视。本文基于目前我国研究生教育工作中存在的问题,结合国内外研究生教育的发展趋势,提出改善研究生教育人力资本投资条件、提高研究生教育绩效的相关制度建议,为推动我国研究生教育事业的发展提供了参考和借鉴。     

Luna 9 photographs: evidence for a fragmental surface layer

The morphological features of the lunar surface photographed by Luna 9 indicate a surficial layer of weakly cohesive to noncohesive frag mental material. Most of this material is finer than a centimeter and probably finer than a few millimeters, although objects of centimeter size and larger are plentiful.     

Intestinal M cells: a pathway for entry of reovirus into the host

Thirty minutes after inoculation of reovirus type 1 into the intestinal lumen of the mouse, viruses were found adhering to the surface of intestinal M cells but not other epithelial cells. Within 1 hour, viruses were seen in the M cell cytoplasm and were associated with mononuclear cells in the intercellular space adjacent to the M cell. These findings suggest that M cells are the site where reovirus penetrates the intestinal epithelium.     

TNF-R1 signaling: a beautiful pathway

Tumor necrosis factor (TNF) is a major mediator of apoptosis as well as inflammation and immunity, and it has been implicated in the pathogenesis of a wide spectrum of human diseases, including sepsis, diabetes, cancer, osteoporosis, multiple sclerosis, rheumatoid arthritis, and inflammatory bowel diseases. The interaction of TNF with TNF receptor-1 (TNF-R1) activates several signal transduction pathways. A common feature of each pathway is the TNF-induced formation of a multiprotein signaling complex at the cell membrane. Over the past decade, many of the components and mechanisms of these signaling pathways have been elucidated. We provide an overview of current knowledge of TNF signaling and introduce an STKE Connections Map that depicts a canonical view of this process.     

Caudate unit responses to nigral stimuli: evidence for a possible nigro-neostriatal pathway

Electrical stimulation of the Substantia nigra evokes depressant and facilitatory responses from individually recorded caudate nucleus neurons. These effects resemble those elicited from caudate cells by microiontophoretic ejections of dopamine. Since histochemical evidence suggests that dopamine-containing fibers link the substantia nigra with the caudate, this pathway may mediate the changes in caudate spike rates produced by nigral stimuli.