Native transfer RNA catalyzes Diels-Alder reaction

In this paper we show that transfer ribonucleic acids (tRNAs) catalyze the Diels-Alder cycloaddition reaction. A new DNA oxidative damage product, 6-furfuryladenine (kinetin) or its riboside (diene), was transformed with dimethyl acetylenedicarboxylate or maleic anhydride (dienophile). The reaction proceeds in the presence of tRNA at high pressure but not at ambient condition. If so tRNA in prebiotic conditions (RNA world) had at least two functions: catalytic and a carrier of genetic information. It means that tRNA at high pressure shows catalytic properties and is a true Diels-Alderase.     

The potato Lhca3.St.1 promoter confers high and stable transgene expression in chrysanthemum,in contrast to CaMV-based promoters

Theenhanced cauliflower mosaic virus 35S (dCaMV) promoter and the potatoLhca3.St.1 promoter were evaluated for their expressionabilities in chrysanthemum. The promoters were fused to the-glucuronidase(GUS) reporter gene with and without flanking matrix-associated regions (MARs).They were transferred into chrysanthemum viaAgrobacterium-mediated transformation. The quantitativeevaluation of GUS activity in a total of 127 independently derivedtransformantsestablished that in chrysanthemum the Lhca3.St.1 promoterwas 175 fold more active in the leaves than the dCaMV promoter was. The latterwas as poor in expression as the single CaMV promoter. The use of suchCaMV-based promoters in the genetic engineering of chrysanthemum should bediscouraged when high levels of transgene expression are desired. No clearinfluence of the presence of MARs was observed on the variability of GUS geneexpression, in contrast to earlier studies in tobacco. This may indicate apossible plant species dependent activity of MAR elements.Lhca3.St.1 promoter-driven GUS activity was relativelyhigher in the stem of chrysanthemum and proved stable over extensive timeperiods. Therefore this potato promoter is attractive to obtain high expressionlevels in chrysanthemum.     

金针菇FV088菌株液体培养工艺的研究

通过单因子试验统计分析,优化筛选了适于金针菇（Flammulinavelutipes）FV088的适宜培养基和摇瓶培养条件,结果表明,其适宜的液体培养基组成为：5.0％玉米粉,2．0％鼓皮,0．L％KH₂PO₄,0．05％MgSO₄·7H₂O,10μgVB₁／100ml,50μgVB₂／100ml;适宜的摇瓶培养条件为：培养基的起始pH6．0～7．0,500ml     

Regulation of n-3 and n-6 Fatty Acid Metabolism in Retinal and Cerebral Microvascular Endothelial Cells by High Glucose

Abstract: The present study was undertaken to determine whether polyunsaturated fatty acid metabolism is affected by high glucose levels in cerebral and retinal microvascular endothelial cells. The metabolism of [3-¹⁴C]22:5n-3 and [1-¹⁴C]18:2n-6 was studied in cells previously cultured for 5 days in normal (5 m M ) or high (30 m M ) glucose medium. After incubation of retinal endothelial cells with [3-¹⁴C]22:5n-3 in the high glucose condition, the formation of labeled 24:6n-3 and 22:6n-3 was increased, and that of labeled 24:5n-3 was decreased, compared with the normal glucose condition. The changes were found for fatty acids esterified in cellular lipids and those released into the medium. After incubation with [1-¹⁴C]18:2n-6, levels of all elongation/desaturation products were increased at the expense of the precursor in retinal endothelial cells cultured in high glucose medium. The changes were primarily found for esterified fatty acids, with the release of n-6 fatty acids being minor in both glucose concentrations. By contrast, high glucose levels did not affect the metabolism of [3-¹⁴C]22:5n-3 and [1-¹⁴C]18:2n-6 in cerebral endothelial cells. The changes in metabolic activity of retinal endothelial cells were not reflected in the fatty acid composition. The present data suggest that high glucose can increase the desaturation process in retinal but not cerebral endothelial cells. This may produce some lipid abnormalities in retinal microvasculature and contribute to altered vascular function observed in diabetic retinopathy.     

Hemoglobin levels in a Himalayan high altitude population

This report presents data on hemoglobin concentrations in a sample of Himalayan high altitude natives measured at their habitual altitude of residence. In this sample of 270 healthy Tibetan adults resident at 3250–3560 m in Upper Chumik, Nepal, the mean hemoglobin concentration is 16.1 ± 1.2 gm/dl among adult males, 14.4 ± 1.4 gm/dl among premenopausal and 15.0 ± 1.1 gm/dl among postmenopausal adult females. 123 of 126 (98%) males, 96 of 100 (96%) premenopausal and 36 of 44 (82%) postmenopausal females have hemoglobin concentrations within two standard deviations of the sea level mean. These data demonstrate that a healthy population may reside at high altitude without the degree of elevation in hemoglobin widely known and cited for Andean highlanders. Comparing published data on mean hemoglobin concentrations of adult Himalayan and Andean samples residing between 3200 m and 4100 m reveals that Himalayan means are systematically lower. This in turn may account for the reported population differences in the prevalence of chronic mountain sickness (Monge's disease). It is hypothesized that Himalayan and Andean highlanders represent alternative patterns of high altitude hematological adaptation.     

A resampling approach for evaluating effects of pasture abandonment on subalpine plant species diversity

Abstract. The decline of species‐rich semi‐natural calcareous grasslands is a major conservation problem throughout Europe. Maintenance of traditional animal husbandry is often recommended as an important management strategy. However, results that underpin such management recommendations were derived predominantly from lowland studies and may not be easily applicable to high mountain areas. In this study we analyse the importance of traditional low‐intensity summer farming (cattle grazing) for vascular plant species diversity of a subalpine region in the northern calcareous Alps in Austria by resampling from an existing dataset on its vegetation. Results indicate a significant long term decline of plant species diversity following abandonment at the landscape scale. In contrast, within‐community effects of pasture abandonment on plant species diversity are equivocal and strongly depend on the plant community. We suppose these differences to be due to diet preferences of cattle as well as to the differential importance of competition for structuring the respective communities. From our results we infer that the main mechanism by which pasture abandonment affects vascular plant species diversity, at least during the first ca. 100 yr documented here, are not local‐scale competitive exclusion processes within persisting communities. Instead, post‐abandonment successional community displacements that cause a landscape scale homogenization of the vegetation cover seem to be primarily responsible for a decline of species diversity. We conclude, that successful management of vascular plant species diversity in subalpine regions of the Northeastern Calcareous Alps will depend on the maintenance of large scale pasture systems with a spatially variable disturbance regime.     

大肠杆菌表达重组人白细胞介素-9的纯化及部分性质

表达重组人白细胞介素－９（ｒｅｃｏｍｂｉｎａｎｔｈｕｍａｎｉｎｔｅｒｌｅｕｋｉｎ－９ｒｈＩＬ－９）的大肠杆菌经破碎、包涵体洗涤、裂解提取、凝胶过滤和离子交换色谱分离,得到了电泳纯的ｒｈＩＬ－９,回收率６６％,分子量与理论值相符,有刺激小鼠骨髓巨核系集落生成的活性．为ｒｈＩＬ－９的大规模制备及更深入的研究奠定了基础     

人工合成表皮生长因子基因在甲基营养型酵母中的高效表达

选用酵母菌偏爱密码子人工合成了编码５１个氨基酸的人表皮生长因子（ｈＥＧＦ）基因．将合成基因与编码酵母α因子前导肽８５个氨基酸的ＤＮＡ片段融合后克隆到醇氧化酶基因启动子下游,并构建出多拷贝表达载体．此载体转化甲基营养型酵母株ＧＳ１１５后筛选出整合型ＭｕｔＳＨｉｓ＋基因型菌株．高密度培养及诱导表达后该株可分泌具完好生物活性和正确物理化学性质的人表皮生长因子,产量达１００ｍｇ／Ｌ,经３次柱层析纯度达９５％以上,为观察其生物学作用打下了良好基础     

Studies on porcine high molecular weight kininogen. An improved method for the purification of porcine high molecular weight kininogen and cleavage of the kininogen by the action of porcine plasma kallikrein

By introduction of stepwise DEAE Sephadex A-50 and copper-Chelating Sepharose 6B column chromatographies, about 18.5 mg of high molecular weight kininogen (HK) composed of a single polypeptide chain was obtained from 500 ml of porcine plasma. Molecular weights of reduced or non-reduced preparation were estimated to be 110 kDa and 116 kDa, respectively, by SDS–PAGE. Using the preparation, cleavage of HK by porcine plasma kallikrein (KK) was investigated. A single polypeptide HK was cleaved into two chains cross-linked by disulfide bond(s), accompanying the release of kinin. Further degradation was not observed. Molecular weights of heavy-chain (H-chain) and light-chain (L-chain) were estimated to be 61 kDa and 56 kDa, respectively, by SDS–PAGE. The amino- (N-) terminal sequences of intact HK, reduced and carboxymethylated- (RCM-) H-chain, RCM-L-chain and the peptide around the kinin moiety obtained by BrCN digestion were determined. Their sequences were highly homologous with those of bovine or human HK. These results indicate that plasma KK first cleaved the Arg-Ser bond of HK, and formed nicked HK. The second cleavage yielded bradykinin (BK) and kinin-free protein, which was apparently of equal size to the nicked HK. The structure of HK was from the N-terminus to the carboxy- (C-) terminus, H-chain-BK-L-chain.     

光周期对飞虱虫疠霉离体培养的生物量及其产孢节律的影响

飞虱虫疠霉（Ｐａｎｄｏｒａｄｅｌｐｈａｃｉｓ）是侵染飞虱和叶蝉等重要作物害虫的昆虫病原真菌。通过在液体及平板培养中研究光周期对菌丝及菌落生长量、产孢节律和产孢量的影响,作者发现光照对液培菌丝的营养生长无显著影响,但长光照液培菌丝的产孢延迟并且产孢量减少,而全黑暗液培菌丝产孢早且产孢量大。但是,光照明显促进全黑暗下液培菌丝的产孢。在平板培养中,长光照能促进菌落生长和产孢;半光照半黑暗虽有利菌落生长,但产孢量很低;光照９ｈ和１８ｈ产孢量较大,但菌落生长较小。无论液体还是平板培养,飞虱虫疠霉均生长良好,但建议在全黑暗条件下进行液体培养,在长光照下进行平板培养。