Cooperation between gene encoding p53 tumour antigen and ras in cellular transformation

The protein p53 is highly expressed in a large variety of transformed cell types originating from diverse species. These include cells transformed by Simian virus 40 (SV40), adenovirus and Abelson virus, as well as a variety of chemically transformed cells. Substantial amounts of p53 are also present in certain non-transformed cells, for example, some embryonic tissues. The protein may be localized in different cellular compartments in normal and transformed cells. The strong correlation between tumorigenicity and high levels of p53 suggests an important role of p53 in tumorigenesis. We report here experiments in which we have co-transfected the murine cellular gene encoding for p53 with a ras gene into primary rat embryo fibroblasts. Our results indicate that the p53-encoding gene can play a causal role in the conversion of normal fibroblasts into tumorigenic cells.     

Nucleotide sequence of cloned cDNA encoding bovine arginine vasopressin-neurophysin II precursor

The sequence of a cDNA encoding the nonapeptide arginine vasopressin (AVP) and its carrier protein, neurophysin II (NpII) from bovine hypothalamus, proves that the 166-amino acid precursor molecule contains a signal peptide of 19 amino acids followed directly by AVP connected to NpII by a Gly-Lys-Arg sequence. The carboxy-terminal region of the precursor contains a naturally occurring glycopolypeptide of 39 amino acids which is separated from NpII by a single arginine residue.     

T cells become licensed in the lung to enter the central nervous system

The blood–brain barrier (BBB) and the environment of the central nervous system (CNS) guard the nervous tissue from peripheral immune cells. In the autoimmune disease multiple sclerosis, myelin-reactive T-cell blasts are thought to transgress the BBB and create a pro-inflammatory environment in the CNS, thereby making possible a second autoimmune attack that starts from the leptomeningeal vessels and progresses into the parenchyma. Using a Lewis rat model of experimental autoimmune encephalomyelitis, we show here that contrary to the expectations of this concept, T-cell blasts do not efficiently enter the CNS and are not required to prepare the BBB for immune-cell recruitment. Instead, intravenously transferred T-cell blasts gain the capacity to enter the CNS after residing transiently within the lung tissues. Inside the lung tissues, they move along and within the airways to bronchus-associated lymphoid tissues and lung-draining mediastinal lymph nodes before they enter the blood circulation from where they reach the CNS. Effector T cells transferred directly into the airways showed a similar migratory pattern and retained their full pathogenicity. On their way the T cells fundamentally reprogrammed their gene-expression profile, characterized by downregulation of their activation program and upregulation of cellular locomotion molecules together with chemokine and adhesion receptors. The adhesion receptors include ninjurin 1, which participates in T-cell intravascular crawling on cerebral blood vessels. We detected that the lung constitutes a niche not only for activated T cells but also for resting myelin-reactive memory T cells. After local stimulation in the lung, these cells strongly proliferate and, after assuming migratory properties, enter the CNS and induce paralytic disease. The lung could therefore contribute to the activation of potentially autoaggressive T cells and their transition to a migratory mode as a prerequisite to entering their target tissues and inducing autoimmune disease.     

Twenty-first-century warming of a large Antarctic ice-shelf cavity by a redirected coastal current

The Antarctic ice sheet loses mass at its fringes bordering the Southern Ocean. At this boundary, warm circumpolar water can override the continental slope front, reaching the grounding line through submarine glacial troughs and causing high rates of melting at the deep ice-shelf bases. The interplay between ocean currents and continental bathymetry is therefore likely to influence future rates of ice-mass loss. Here we show that a redirection of the coastal current into the Filchner Trough and underneath the Filchner-Ronne Ice Shelf during the second half of the twenty-first century would lead to increased movement of warm waters into the deep southern ice-shelf cavity. Water temperatures in the cavity would increase by more than 2 degrees Celsius and boost average basal melting from 0.2 metres, or 82 billion tonnes, per year to almost 4 metres, or 1,600 billion tonnes, per year. Our results, which are based on the output of a coupled ice-ocean model forced by a range of atmospheric outputs from the HadCM3 climate model, suggest that the changes would be caused primarily by an increase in ocean surface stress in the southeastern Weddell Sea due to thinning of the formerly consolidated sea-ice cover. The projected ice loss at the base of the Filchner-Ronne Ice Shelf represents 80 per cent of the present Antarctic surface mass balance. Thus, the quantification of basal mass loss under changing climate conditions is important for projections regarding the dynamics of Antarctic ice streams and ice shelves, and global sea level rise.     

Genome divergence in two Prochlorococcus ecotypes reflects oceanic niche differentiation

The marine unicellular cyanobacterium Prochlorococcus is the smallest-known oxygen-evolving autotroph. It numerically dominates the phytoplankton in the tropical and subtropical oceans, and is responsible for a significant fraction of global photosynthesis. Here we compare the genomes of two Prochlorococcus strains that span the largest evolutionary distance within the Prochlorococcus lineage and that have different minimum, maximum and optimal light intensities for growth. The high-light-adapted ecotype has the smallest genome (1,657,990 base pairs, 1,716 genes) of any known oxygenic phototroph, whereas the genome of its low-light-adapted counterpart is significantly larger, at 2,410,873 base pairs (2,275 genes). The comparative architectures of these two strains reveal dynamic genomes that are constantly changing in response to myriad selection pressures. Although the two strains have 1,350 genes in common, a significant number are not shared, and these have been differentially retained from the common ancestor, or acquired through duplication or lateral transfer. Some of these genes have obvious roles in determining the relative fitness of the ecotypes in response to key environmental variables, and hence in regulating their distribution and abundance in the oceans.     

关于山西省土地后备资源开发的思考

阐述了土地后备资源开发对于农业及经济发展的意义，通过对山西省太谷县土地后备资源开发利用潜力的评价分析，从生态环境保护、遵循土地适宜性原则、科学评价、综合整理等方面提出了合理开发土地后备资源的几点建议。     

Common variation at 3p22.1 and 7p15.3 influences multiple myeloma risk

To identify risk variants for multiple myeloma, we conducted a genome-wide association study of 1,675 individuals with multiple myeloma and 5,903 control subjects. We identified risk loci for multiple myeloma at 3p22.1 (rs1052501 in ULK4; odds ratio (OR) = 1.32; P = 7.47 × 10(-9)) and 7p15.3 (rs4487645, OR = 1.38; P = 3.33 × 10(-15)). In addition, we observed a promising association at 2p23.3 (rs6746082, OR = 1.29; P = 1.22 × 10(-7)). Our study identifies new genomic regions associated with multiple myeloma risk that may lead to new etiological insights.     

农户对土地整治项目管理的认知与响应研究——基于重庆市6个区县22个村的调查

以位于重庆市西部,渝东北,渝东南三大区域的6个区县22个行政村的农户为调研对象,通过问卷调查法了解农民认识、参与农村土地整治项目管理的现状及愿望,以及运用logistic回归模型分析影响农民参与农村土地整治项目管理意愿的主导因素.研究结果表明:73.93%的被调查农民表示愿意参与农村土地整治项目管理,影响农民参与农村土地整治项目管理的因素主要为农民的文化程度、农户类型、农民获取相关信息的渠道、农民对管理内容的了解程度、农民参与管理的方式、农民签订管理协议的情况以及农民参与土地流转的情况,可通过拓宽农民了解信息的渠道、鼓励农民参与项目各个阶段管理、丰富农民参与管理的方式、加强农民管理协议的签订、从而提高农民参与项目管理的积极性,进而提高农村土地整治管理绩效.