Chimeric contribution of human extended pluripotent stem cells to monkey embryos ex vivo

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Effects of recombinant human macrophage colony-stimulating factor on atherosclerotic lesions established in the aorta of high cholesterol-fed rabbits

Anti-atherosclerotic effects of human macrophage colony-stimulating factor were investigated using rabbits fed a high cholesterol diet. Rabbits fed a diet containing 2% cholesterol for 59 days developed hyperlipidemia and atheromatous aortic plaques. They were then administered 80 microg/kg/day of either macrophage colony-stimulating factor or human serum albumin, as a control, for the next 12 weeks. Compared with the control group, rabbits treated with macrophage colony-stimulating factor had significantly fewer plaques on the inner surface of the thoracic and abdominal aortae, and half the sectional area of thickened intima in the aortic arch, as well as in the thoracic and abdominal aortae. Macrophage colony-stimulating factor also decreased the cholesterol content of the atherosclerotic lesions. Serobiochemical analyses revealed that macrophage colony-stimulating factor increased the levels of high density lipoprotein-cholesterol significantly, without influencing other lipid parameters such as the level of low density lipoproteins. The effects of macrophage colony-stimulating factor were evident until the fourth week of drug injection, at which time anti-human macrophage colony-stimulating factor antibodies were clearly induced in the serum. These results indicate that exogenously administered macrophage colony-stimulating factor suppresses atherosclerotic lesions induced by a high cholesterol diet by activating lipid metabolism in vivo.     

Cadmium exposure in tobacco workers: possible renal effects.

Cadmium is a nephrotoxic metal widely used in industry and the main source of Cd in general population is smoking. Considering that the source of Cd in cigarettes is the tobacco leaf, the exposure to Cd was evaluated in workers employed at a tobacco leaf processing factory. Blood and urinary Cd levels were measured by flameless atomic absorption spectrometry in 87 workers and 35 controls. Urinary enzymes, total protein, albumin and uric acid were also determined to investigate the possible nephrotoxic effects of Cd. Blood Cd levels were significantly higher in workers (1.63 +/- 1.95 microg/L) than in controls (0.91 +/- 1.15 microg/L) (p = 0.044). The increase observed in urinary Cd levels of workers was non significant (0.56 +/- 0.5 microg/g creatinine in workers and 0.46 +/- 0.5 microg/g creatinine in controls). Both in workers and in controls, subjects smoking >10 cigarettes/day showed significantly increased blood Cd levels compared to non-smokers (p = 0.000 and p = 0.011, respectively). In workers, urinary alkaline phosphatase (ALP), gamma glutamyl transferase (GGT), total protein, and uric acid were observed to be significantly increased (p = 0.013, p = 0.000, p = 0.000, p = 0.025, respectively), ALP, GGT and total protein being positively correlated with Cd in urine. In conclusion, the workers in the tobacco leaf processing factory were found to be exposed to Cd compared to the general population. The increase in the urinary enzymes and proteins suggests that an exposure to Cd affects kidney functions even below the toxic limits generally accepted.     

Synthesis and in vitro evaluation of novel small molecule inhibitors of bacterial arylamine N-acetyltransferases (NATs)

The synthesis and inhibitory activity of a series of 5-substituted-(1,1-dioxo-2,3-dihydro-1H-1 lambda(6)-benzo[e][1,2]thiazin-4-ylidene)-thiazolidine-2,4-dione derivatives as competitive inhibitors of recombinant bacterial arylamine-N-acetyltransferases (NATs) are described. The most potent NAT inhibitors are those that contain planar hydrophobic substituents on the sultam nitrogen.     

伊洛河流域外来草本植物分布格局

外来生物入侵及其防治已经成为生态学关注的重点和热点问题.目前的研究主要集中在外来入侵种上,然而入侵种仅占外来种中很少一部分,因此,研究外来种现有分布格局对研究生物入侵及其防治有重要意义.以伊洛河流域草本植物群落中的外来种为对象,沿河从河源地到入黄河口选取典型样地,在调查流域内草本植物群落中物种组成的基础上选取外来种,并对外来种种类组成及其分布格局进行研究.结果表明:流域内有外来草本植物27种,分属于15科,种类较多的科为菊科、苋科和豆科;引入方式以有意引种为主.流域横向不同生境间,河滩地在水流的养分富集、季节性洪水物理干扰及人为活动扰动作用下,呈现出受外来种分布较多,而受人类活动扰动最强且营养丰富的农田分布较小的分布格局;纵向环境梯度下,上游河源山地属于自然植被区,人为干扰较轻,且受外来种影响较小;中游丘陵区从自然生态系统向农业生态系统的过渡区域,人类活动的扰动有所加强;下游平原农业区,人类活动强烈,区域内以人工生态系统为主,群落物种组成简单但受外来种影响最大,受自然环境和人类活动的双重影响.不同物种在不同生境间差异明显,其中,小蓬草、钻叶紫菀和反枝苋广泛分布于3种生境中.总体上,伊洛河外来草本植物分布格局在自然因素的基础上强烈受人为因素的影响,呈现出从上游到下游逐渐增多的趋势.     

Sulfur assimilation by Oxyrrhis marina feeding on a 35S‐DMSP‐labelled prey

A laboratory grazing experiment was conducted with the aim of quantifying the sulfur assimilation by a herbivore protist feeding on a dimethylsulfoniopropionate (DMSP)‐containing phytoplankter. When supplied with dissolved ³⁵S‐DMSP, cultures of an axenic strain of the diatom Thalassiosira pseudonana took up 60–95% of the added radioisotope and accumulated it untransformed in the cytoplasm. Radiolabelled diatom cells were offered as prey to the heterotrophic dinoflagellate Oxyrrhis marina. After 32 h in the dark, all the prey had been grazed and digested, leaving only radiolabelled O. marina in the grazing bottles and thus providing an estimate of the percentage of DMSP‐sulfur retained by the predator. Subsequent precipitation with cold trichloroacetic acid (TCA) provided the fraction of retained DMSP‐S that had been assimilated into the micrograzer macromolecules. In parallel incubations with predator and dissolved ³⁵S‐DMSP only (no prey), O. marina (and their closely associated bacteria) took up the radiolabelled substrate osmotrophically to an activity of 0.04 dpm cell^?1 and assimilated it all into macromolecules. By correcting grazing ³⁵S‐DMSP assimilation for osmotrophic ³⁵S‐DMSP assimilation, and comparing it with the ingested radioisotope, the percentage of ingested DMSP‐sulfur retained and assimilated by the predator was determined to be 32 ± 4%. This is the first study that provides direct evidence that ingestion of a DMSP‐containing prey supplies structural sulfur to a herbivore protist and that quantifies this assimilative supply at one‐third of ingested DMSP.     

Enhanced production and secretion of streptokinase into extracellular medium in Escherichia coli by removal of 13 N-terminal amino acids

The production and secretion of streptokinase using OmpA signal sequence in E. coli was enhanced by removing the 13 N-terminal amino acids (SK(N13). The secretion level of SK(N13 protein into the extracellular medium was two times higher than that of wild-type streptokinase. About 4500 IU of SK(N13 protein per 1 ml LB-ampicillin medium was secreted into extracellular medium at 12 hours after induction. Fully active and enhanced extracellular preparation of the mutant streptokinase may be a potential alternative source for the simple downstream processing