蝮蛇毒抗凝血活酶组份及几种蛇毒粗毒对人红细胞和血小板的作用

蝮蛇毒抗凝血活酶组分及蝗蛇毒、圆斑蝰蛇毒和眼镜蛇毒粗毒,不仅能够水解血浆中的磷脂,而且还能水解完整人红细胞膜和完整人血小板膜上的磷脂。但是五步蛇毒和金环蛇毒粗毒却不能水解完整人血小板膜上的磷脂。 扫描电镜观察表明,由于抗凝血活酶组份和几种蛇毒粗毒的作用,人红细胞和人血小板的形态发生了巨大的变化;人红细胞由正常的双圆盘形变成带刺的小球,人血小板的外形变成蜂窝状。     

Reproductive success and risk of predation in normal and melanistic colour morphs of the adder, Vipera berus

In a population of adders (Vipera berus) in Southwest Sweden, melanistic males were heavier than normal coloured males of the same length. Victory in male-male sexual combats was positively related to size. Higher risk of predation in the black morph was inferred from experiments showing a high predator attack rate on models of the black morph. Even the bright colour in newly moulted basking males of the normal morph gives cryptic protection. In females, melanism probably also affects body size and risk of predation by visually searching predators. The thermoregulatory influence of black colour, the reproductive success and the maintenance of two colour morphs in the population are discussed.     

Metalloproteinase with factor X activating and fibrinogenolytic activities from Vipera berus berus venom

We have previously shown that Vipera berus berus venom contains several factor X activating enzymes. In the present study we have investigated one of them. The enzyme was separated from venom by gel filtration on Sephadex G-100 superfine and chromatography on agarose HPS-7 and phenyl-agarose. The enzyme is a glycosylated metalloproteinase containing hexoses, hexosamines and neuraminic acid. The purified factor X activating enzyme consists of two equal chains (59 kDa). The specificity studies have shown that enzyme is nonspecific factor X activating proteinase hydrolysing also proteins such as azocasein, gelatin and fibrinogen. The enzyme hydrolyses oxidized insulin B-chain at the positions Ala¹⁴–Leu¹⁵ and Tyr¹⁶–Leu¹⁷ but it is inactive on fibrin, plasminogen and prothrombin. We used 8–10 amino acid residues containing peptides, which reproduce the sequence around the cleavage sites in factor X, factor IX and fibrinogen, as potential substrates for enzyme. Cleavage products of peptide hydrolysis were determined by MALDI-TOF MS. The peptide Asn–Asn–Leu–Thr–Arg–Ile–Val–Gly–Gly—factor X fragment was cleaved by enzyme at positions Leu³–Thr⁴ and Arg⁵–Ile⁶. The fibrinogen peptide fragment Glu–Tyr–His–Thr–Glu–Lys–Leu–Val–Thr–Ser was hydrolysed at position Lys⁶–Leu⁷.     

蛇伤凉血合剂治疗蝰蛇咬伤的疗效观察

目的观察蛇伤凉血合剂对蝰蛇咬伤的临床疗效。方法将62例病人分为治疗组和对照组,两组均给予常规治疗,治疗组加服蛇伤凉血合剂。观察比较两组预后,局部组织坏死发生率,肢体功能受限发生率,肾损害发生率和血液透析率,住院时间等指标。结果两组病人的临床疗效、肿胀消退时间、疼痛缓解时间、局部坏死发生率、致残率、肾损害发生率和血液透析率、住院时间均有显著性差异（P〈0.05）。结论蛇伤凉血合剂对蝰蛇咬伤有显著疗效。     

Vertebrate evolution reflected in the evolution of nuclear ribosomal internal transcribed spacer 2

In eukaryotes, mature rRNA sequences are produced from single large (45S) precursor (pre-rRNA) as the result of successive removal of spacers through a series of rapid and intricate actions of endo- and exonucleases. The excision of internal transcribed spacer (ITS2), a eukaryotic-specific insertion, remains the most elusive processing step. ITS2 is the element mandatory for all eukaryotic pre-rRNAs that contain at least three processing cleavage sites for precise 5.8S and 28S formation. Conserved core sequences (cis-elements) binding to trans-factors provide for precise rRNA processing, whereas rapidly diverging regions between the core sequences preserve internal complementarity, which guarantees the spatial integrity of ITS2. Characteristic differences in the formation of such insertions during evolution should reflect the relationships between taxa. The phylogeny of the reptiles and the relationships between taxa proposed by scientists are controversial. To delineate the structural and functional features preserved among reptilian ITS2s, we cloned and sequenced 58 ITS2s belonging to four reptile orders: Squamata, Crocodilians, Aves, and Testudines. We studied the subsequent alignment and folding of variable regions. The sizes and packing of the loop–stems between conserved consensus segments in reptiles vary considerably between taxa. Our phylogenetic trees constructed on the basis of the reptile ITS2s primary structural alignments revealed a split between Iguania clade and all other taxa. True lizards (suborder Scleroglossa) and snakes (suborder Serpentes) show sister relationships, as well as the two other reptilian orders, Crocodilia + Aves and Testudines. In summary, our phylogenetic trees exhibit a mix of specific features deduced or, to the contrary, rejected earlier by other authors.