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61.
The N-terminal signal sequence of glucitol pcrmease of Escherichia Coli (Gut22) and its analogue (Gut22Ana) were synthesized. The analogue had a Pro residue substituting for the His at the 7th position of Gut22 and a Val residue substituting for the Glu at the 10th position. The intrinsic fluorescence emission spectra indicated that the binding of Gut22 with lipid bilayer was much stronger than that of Gut22Ana. The leakage experiments with calcein-loaded liposomes showed that Gut22 strongly perturbed lipid bilayers while Gut22Ana did not. The apparent partition constant of Gut22 for partitioning into phosphatidylserine/phosphatidylcholine bilayers was measured; the effect of membrane potential on the interaction of Gut22 with lipid bilayers was studied and the conformation changes of Gut22 and Gut22Ana upon interacting with liposomes were studied by the method of circular dichroism analysis. 相似文献
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64.
本文记述中国土厉螨属1新种,王氏土厉螨Ololaelepswangi,sp.nov,新种的模式标本保存在宁夏回族自治区地方病防治所。 相似文献
65.
Temporal and spatial variations in the oxygen-18 content of leaf water in different plant species 总被引:7,自引:3,他引:4
Temporal variations in the δ18 oxygen (δ18O) content of water transpired by leaves during a simulated diurnal cycle fluctuated around the δ18O content of the source water. Reconstructed variations in the δ18O values of leaf water differed markedly from those predicted by conventional models. Even when transpiring leaves were maintained under constant conditions for at least 3 h, strict isotopic steady-state conditions of leaf water (equality of the 18O/16O ratios in the input and transpired water) were rarely attained in a variety of plant species (Citrus reticu-lata, Citrus paradisi, Gossypium hirsutum, Helianthus annuns, Musa musaceae and Nicotinia tabacum). Isotopic analysis of water transpired by leaves indicated that leaves approach the isotopic steady state in two stages. The first stage takes 10 to 35 min (with a rate of change of about 3–3%h?1), while in the second stage further approach to the isotopic steady state is asymptotic (with a rate of change of about 0–4% h?1), and under conditions of low transpiration leaves can last for many hours. Substantial spatial isotopic heterogeneity was maintained even when leaves were at or near isotopic steady state. An underlying pattern in this isotopic heterogeneity is often discerned with increasing 18O/16O ratios from base to tip, and from the centre to the edges of the leaves. It is also shown that tissue water along these spatial isotopic gradients, as well as the average leaf water, can have 18O/16O ratios both lower and higher than those predicted by the conventional Craig and Gordon model. We concluded, first, that at any given time during the diurnal cycle of relative humidity the attainment of an isotopic steady state in leaf water cannot be assumed a priori and, secondly, that the isotopic enrichment pattern of leaf water reflects gradual enrichment along the water-flow pathway (e.g. as in a string of pools), rather than a single-step enrichment from source water, as is normally assumed. 相似文献
66.
西藏厚厉螨属一新种和毛绥螨属一新种(蜱螨亚纲:厚厉螨科,裂胸螨科) 总被引:2,自引:0,他引:2
本文报道革螨二新种,西藏厚厉螨Pachylaelapsxizangensissp.nov.和亚东毛绥螨Lasioseiusyadongensissp.nov,1985年采自西藏亚东。 相似文献
67.
本文记述中国弯茎叶蝉属FlexocerusKnohetFang1新种,吴萸弯茎叶蝉Flexocerusevodianussp.nov.,新种外形特征与弯茎叶蝉FlexocerusflexureuskuohetFang相似。模式标本保存在贵州农学院。 相似文献
68.
中国厕蝇属一新种(双翅目:厕蝇科) 总被引:1,自引:0,他引:1
本文记述采自山西省的厕蝇属Fannia R.-D.,1830一新种。录属于瘤胫厕蝇群xcalaris-group,胸刺厕蝇亚群fuscula-subgroup,命名为突尾厕蝇Fannia processicauda sp.nov.,新种模式标本保存于山西省大同市地方病防治所。 相似文献
69.
本文利用印迹杂交技术对中国华北地区黑线姬鼠Apodemusagrariuspalidior和韩国黑线姬鼠A.agrariuscoreae共107号标本的线粒体DNA(mitochondrialDNA,mtD-NA),通过8种限制性内切酶的消化,进行了限制性片段的分析。共检出35种限制性片段和12种单倍体类型。12种单倍型在平均离散度为1.01%时聚合为两个亚群:一个亚群为黑线姬鼠华北亚种,由采自中国4个不同地区的51号标本的4种单倍型所组成;另一个亚群为黑线姬鼠朝鲜亚种,由采自韩国4个不同地区的56号标本的8种单倍型所组成。黑线姬鼠华北亚种和朝鲜亚种在mtDNA表型上表现出一定差异,这在分子水平上确立了两亚种的分类地位。为了进一步澄清黑线姬鼠种下分类的混乱,很有必要对中国其他地区的标本进行该项研究 相似文献
70.
鲨鱼软骨制剂抑制血管生成的研究 总被引:23,自引:0,他引:23
以鲨鱼软骨为原料,经盐酸胍抽提,丙酮分级沉淀, 超滤等步骤得到鲨鱼软骨制剂(shark cartilage preparation,SCP). 利用整装细胞扫描电镜方法测定SCP对血管内皮细胞骨架系统的影响,体外细胞迁移实验测定它对内皮细胞迁移的抑制效应,及鸡胚绒毛尿囊膜实验测定对血管生成的抑制效应. 结果表明SCP能显著抑制内皮细胞的骨架形成;显著抑制内皮细胞的迁移,并有明显的浓度依赖关系;显著抑制鸡胚绒毛尿囊膜的血管生成. 细胞骨架是细胞分裂增殖及运动迁移的基础,血管内皮细胞的运动迁移又是血管生成的基础,因此SCP的作用机理可能是通过抑制细胞骨架的形成,抑制内皮细胞的运动迁移,从而抑制血管生成. 相似文献