烙铁头蛇毒纤维蛋白原溶酶研究 Ⅱ: 对纤维蛋白原及凝血酶的作用

烙铁头蛇毒纤维蛋白原-纤维蛋白转换实验表明: TMVFg水解纤维蛋白原产生 的纤维蛋白原断片除具有抗凝血酶、抑制纤维蛋白聚合活性外, 还能促进纤维 蛋白的聚合。因此, 烙铁头蛇毒纤维蛋白原溶酶TMVFg将成为研究血液凝固调 节 系统及血小板聚集第三条途径的强有力试剂。

Isolation and preliminary characterization of a 22-kDa protein with trypsin inhibitory activity from toad Bufo andrewsi skin

A novel trypsin inhibitor termed BATI was purified to homogeneity from the skin extracts of toad Bufo andrewsi by successive ion-exchange, gel-filtration and reverse-phase chromatography. BATI is basic single chain glycoprotein, with apparent molecular weight of 22 kDa in SDS-PAGE. BATI is a thermal stable competitive inhibitor and effectively inhibits trypsin's catalytic activity on peptide substrate with the inhibitor constant (K-i) value of 14 nM and shows no inhibitory effect on chymotrypsin, thrombin and elastase. The N-terminal sequence of BATI is EKDSITD, which shows no similarity with other known trypsin inhibitors. (c) 2005 Elsevier Ltd. All rights reserved.

Novel cathelicidin-derived antimicrobial peptides from Equus asinus

In the present study, EA-CATH1 and EA-CATH2 were identified from a constructed lung cDNA library of donkey (Equus asinus) as members of cathelicidin-derived antimicrobial peptides, using a nested PCR-based cloning strategy. Composed of 25 and 26 residues, respectively, EA-CATH1 and EA-CATH2 are smaller than most other cathelicidins and have no sequence homology to other cathelicidins identified to date. Chemically synthesized EA-CATH1 exerted potent antimicrobial activity against most of the 32 strains of bacteria and fungi tested, especially the clinically isolated drug-resistant strains, and minimal inhibitory concentration values against Gram-positive bacteria were mostly in the range of 0.3-2.4 mu g center dot mL-1. EA-CATH1 showed an extraordinary serum stability and no haemolytic activity against human erythrocytes in a dose up to 20 mu g center dot mL-1. CD spectra showed that EA-CATH1 mainly adopts an alpha-helical conformation in a 50% trifluoroethanol/water solution, but a random coil in aqueous solution. Scanning electron microscope observations of Staphylococcus aureus (ATCC2592) treated with EA-CATH1 demonstrated that EA-CATH could cause rapid disruption of the bacterial membrane, and in turn lead to cell lysis. This might explain the much faster killing kinetics of EA-CATH1 than conventional antibiotics revealed by killing kinetics data. In the presence of CaCl2, EA-CATH1 exerted haemagglutination activity, which might potentiate an inhibition against the bacterial polyprotein interaction with the host erythrocyte surface, thereby possibly restricting bacterial colonization and spread.

A unique group of inactive serine protease homologues from snake venom

A number of inactive serine protease homologues (SPHs), which have poorly understood functions, have been identified in invertebrates and vertebrates. Recently, several SPH transcripts have been reported from snake venom glands, which provide potential ne

具有避孕作用的杀微生物剂

杀微生物剂是近年来发展起来的一种阴道或宫颈局部用药以防止性传播疾病的药物制剂。理想的 杀微生物剂应安全、高效、廉价和稳定。杀微生物剂不一定都具有杀精子作用, 兼有杀精子作用的杀微生物剂是目 前的研究热点。目前研制中的杀微生物剂共有种, 其中大约有种兼有杀精子和避孕作用, 根据作用机制将这 些具有避孕作用的杀微生物剂分为类。杀微生物剂的研发面临着一些困难, 但具有潜在的应用前景和广泛市场。

Triterpenoids from Schisandra lancifolia with anti-HIV-1 activity

A new trinorcycloartane triterpenoid, lancifodilactone H (1), and a new A ring-secocycloartane triterpenoid, lancifoic acid A (2), together with a known compound, nigranoic acid (3), were isolated from the leaves and stems of Schisandra lancifolia. Their

云南鱼类多样性和面临的危机

迄今共记载云南土著鱼类432种,占全国淡水鱼类总种数1023种的42.2%,显示云南是我国淡水鱼类多样性最为丰富的省区之一。全省大约有1/3的种类日趋减少或濒临绝灭,湖泊鱼类尤为突出,濒危种几乎达到2/3。

Nest site selection by Black-necked Crane Grus nigricollis in the Ruoergai Wetland, China

From 5 May 2003 to early June 2005, nest site selection of Black-necked Cranes Grits nigricollis was studied at the Ruoergai Wetland Nature Reserve (RWNR), an important breeding area for the species in China. Results showed that the crane nests only in we

白眉长臂猿鸣叫的时间特征

滇西白眉长臂猿(Hylobates hoolock)鸣叫主要发生在上午,最早开始于黎明时分,最晚则在下午16:30以后。不同季节鸣叫发生时间有显著差异,可能与黎明时间(光亮度)不同有关,但持续时间无差异。同一季节异地间鸣叫持续时间差异显著。气候、猿群密度、栖息地状态对鸣叫有一定影响,但未见明显相关性。与黑长臂猿的种间比较表明,白眉长臂猿的鸣叫声在时间分布上有较大的散开度,持续时间也较长,二者有显著差异。