New evidence on the earliest human presence at high northern latitudes in northeast Asia

The timing of early human dispersal to Asia is a central issue in the study of human evolution. Excavations in predominantly lacustrine sediments at Majuangou, Nihewan basin, north China, uncovered four layers of indisputable hominin stone tools. Here we report magnetostratigraphic results that constrain the age of the four artefact layers to an interval of nearly 340,000 yr between the Olduvai subchron and the Cobb Mountain event. The lowest layer, about 1.66 million years old (Myr), provides the oldest record of stone-tool processing of animal tissues in east Asia. The highest layer, at about 1.32 Myr, correlates with the stone tool layer at Xiaochangliang, previously considered the oldest archaeological site in this region. The findings at Majuangou indicate that the oldest known human presence in northeast Asia at 40 degrees N is only slightly younger than that in western Asia. This result implies that a long yet rapid migration from Africa, possibly initiated during a phase of warm climate, enabled early human populations to inhabit northern latitudes of east Asia over a prolonged period.     

重组人甲状旁腺激素(1-34)在大肠杆菌中的表达与纯化

将化学合成的rhPTH(1-34)基因用PCR扩增后,克隆至表达载体pET-35b( ),使rhPTH(1—34)融合于纤维素结合结构域(CBDdos)的羧基端,并得到高效表达．融合蛋白经纤维素树脂亲和层析纯化后,经Factor Xa裂解释放出rhPTH(1-34),再通过纤维素树脂亲和层析、C4反向高效液相色谱纯化得到rhPTH(1-34)纯品．每升培养液可获取3mg高纯度的rhPTH(1-34)．经质谱测定,所得样品的分子量为4117．0Da,与rhPTH(1—34)理论分子量一致．     

Effects of truncated mutants of the ε subunit of chloroplast ATP synthase on the fast phase of millisecond delayed light emission of chloroplast and its ATP synthesis ability

The ε subunit of the chloroplast ATP synthase and the truncated ε mutants which lack some amino acid residues from the N-terminus or C-terminus were overexpressed in E. coil When the ε subunit or the truncated ε proteins was added to the spinach chloroplast suspension, both the intensity of the fast phase of millisecond delayed light emission (ms-DLE) and the cyclic and noncyclic photophosphorylation activity of chloroplast were enhanced. With an increase in the number of residues deleted from the N-terminus, the enhancement effect of the N-terminal truncated proteins decreased gradually. For the C-terminal truncated proteins, the enhancement effect increased gradually with an increase in the number of residues deleted from the C-terminus. Besides, the ATP synthesis activity of ε-deficient membrane reconstituted with the ε subunit or the truncated ε proteins was compared. The ATP synthesis activity of reconstituted membrane with the N-terminal truncated proteins decreased gradually as the number of residues deleted from the N-terminus increased. For the C-terminal truncated proteins, the ATP synthesis activity of reconstituted membrane increased gradually with an increase in the number of residues deleted from the C-terminus, but was still lower than that of the wild type ε protein. These results suggested that: (a) the N-terminal domain of the ε subunit of the chloroplast ATP synthase could affect the ATP synthesis activity of ATP synthase by regulating the efficiency of blocking proton leakage of ε subunit; and (b) the C-terminal domain of the ε subunit of the chloroplast ATP synthase had a subtle function in modulating the ATP synthesis ability of ATP synthase.     

Isolation,purification and characterization of a new organphosphorus hydrolase OPHC2

A bacterium with the capability of degrading organphosphorus, identified as Pseudomonas pseudoaicaligenes, is isolated from OP-treated soil. The organphosphorus hydrolase OPHC2 from this bacterium has been purified and characterized. OPHC2 has optimum activity for the reaction at 65℃ and pH 9.0 with methyl parathion as a substrate, it also shows good thermal and pH stability. Most metal ions and chemicals have no effect on the activity of OPHC2. The analyses of nucleotide sequence encoding OPHC2 and amino acid sequence of OPHC2 show that there are lower homologies with those of organphosphorus hydrolase reported in GenBank.     

Persistent organic pollutants PCNs and PBDEs in sediments from coastal waters of Qingdao,Shandong Peninsula

Thirty-one congeners of polychlorinated naphthalenes (PCNs) and 21 congeners of polybrominated diphenylethers(PBDEs)in surface sediments at 5 stations and one mussel sample from Qingdao coastal waters were analyzed. The maximum contents occur at the station near the Haibo River mouth. The total PCNs contents are in the range of 212-1209 pg/g dw, dominated by tri-Cl CN. The total PBDEs contents are in the range of 117-5510 pg/g dw,dominated by tri- to hexa-BrBDEs. The local sources of PCNs are likely from combustion processes such as incinerations and coal burnings. The sources of PBDEs are molecular diffusion from the materials containing them. Except for the area near the river mouth where is affected by the sewage sludges, an important source of PCNs and PBDEs in this area is believed to be the atmospheric deposition. Mussels enrich PCNs and PBDEs relative to the sediments. The total TEQs of PCNs in mussels are lower than the total TEQs of PCBs.     

Improved elastase production by Bacillus sp. EL31410—further optimization and kinetics studies of culture medium for batch fermentation

An efficient culture medium producing a bacterial elastase with high yields was developed further following preliminary studies by means of response surface method. Central composite design (CCD) and response surface methodology were applied to optimize the medium constituents. A central composite design was used to explain the combined effect of three medium constituents, viz, glucose, K(2)HPO(4), MgSO(4).7H(2)O. The strain produced more elastase in the completely optimized medium, as compared with the partially optimized medium. The fitted model of the second model, as per RSM, showed that glucose was 7.4 g/100 ml, casein 1.13 g/100 ml, corn steep flour 0.616 g/100 ml, K(2)HPO(4) 0.206 g/100 ml and MgSO(4).7H(2)O 0.034 g/100 ml. The fermentation kinetics of these two culture media in the flask experiments were analyzed. It was found that the highest elastase productivity occurred at 54 hours. Higher glucose concentration had inhibitory effect on elastase production. At the same time, we observed that the glucose consumption rate was slow in the completely optimized medium, which can explain the lag period of the highest elastase production. Some metal ions and surfactant additives also affected elastase production and cell growth.     

Land degradation, government subsidy, and smallholders＇ conservation decision： the case of the loess plateau in China

Land degradation is one of the severe environmental problems in China. In order to combat land degradation, a soil conservation program was introduced since 2000 to reduce soil erosion by converting slope-cultivated land into forestry and pasture. This paper represents the first systematic attempt to investigate the impact of the soil conservation program on land degradation in the loess plateau. The results indicate that the soil conservation program to convert slope fields into forest or pasture is an effective way to combat soil erosion. However, a subsidy that is higher than profit of land use activity of slope fields before their conversion into forest and pasture is needed to encourage farmers to join the conservation program. A policy measure to encourage and assist farmers to develop sedentary livestock by using crops produced from fields as well as fodder and forage grass from the converted slope fields might contribute to combat soil erosion. Increase in off-farm job opportunities may encourage households to reduce cultivation in slope fields. That implies a policy measure to encourage rural urbanization might contribute to combat soil erosion.     

Nitric oxide regulates the heart by spatial confinement of nitric oxide synthase isoforms

Subcellular localization of nitric oxide (NO) synthases with effector molecules is an important regulatory mechanism for NO signalling. In the heart, NO inhibits L-type Ca2+ channels but stimulates sarcoplasmic reticulum (SR) Ca2+ release, leading to variable effects on myocardial contractility. Here we show that spatial confinement of specific NO synthase isoforms regulates this process. Endothelial NO synthase (NOS3) localizes to caveolae, where compartmentalization with beta-adrenergic receptors and L-type Ca2+ channels allows NO to inhibit beta-adrenergic-induced inotropy. Neuronal NO synthase (NOS1), however, is targeted to cardiac SR. NO stimulation of SR Ca2+ release via the ryanodine receptor (RyR) in vitro, suggests that NOS1 has an opposite, facilitative effect on contractility. We demonstrate that NOS1-deficient mice have suppressed inotropic response, whereas NOS3-deficient mice have enhanced contractility, owing to corresponding changes in SR Ca2+ release. Both NOS1-/- and NOS3-/- mice develop age-related hypertrophy, although only NOS3-/- mice are hypertensive. NOS1/3-/- double knockout mice have suppressed beta-adrenergic responses and an additive phenotype of marked ventricular remodelling. Thus, NOS1 and NOS3 mediate independent, and in some cases opposite, effects on cardiac structure and function.     

汽车虚拟设计中UG的应用

三维模型虚拟设计是机械设计的必然趋势 ,本文阐述了三维设计软件UG在生成汽车的各部件中的应用 ,实现了UG环境下三维汽车模型虚拟装配过程。实践证明 ,采用UG软件可以把机械设计从“二维平面”设计引入到“三维世界”。     

Molecular identification of a danger signal that alerts the immune system to dying cells

In infections, microbial components provide signals that alert the immune system to danger and promote the generation of immunity. In the absence of such signals, there is often no immune response or tolerance may develop. This has led to the concept that the immune system responds only to antigens perceived to be associated with a dangerous situation such as infection. Danger signals are thought to act by stimulating dendritic cells to mature so that they can present foreign antigens and stimulate T lymphocytes. Dying mammalian cells have also been found to release danger signals of unknown identity. Here we show that uric acid is a principal endogenous danger signal released from injured cells. Uric acid stimulates dendritic cell maturation and, when co-injected with antigen in vivo, significantly enhances the generation of responses from CD8+ T cells. Eliminating uric acid in vivo inhibits the immune response to antigens associated with injured cells, but not to antigens presented by activated dendritic cells. Our findings provide a molecular link between cell injury and immunity and have important implications for vaccines, autoimmunity and inflammation.