Structure-activity relationships of a snake cathelicidin-related peptide, BF-15

Cathelicidin-BF15 (BF-15) is a 15-mer peptide derived from Cathelicidin-BF (BF-30), which is found in the venom of the snake Bungarus fasciatus and exhibits broad antimicrobial activity. Since BF-15 retains most part of the antimicrobial activity of BF-30 but has significantly reduced haemolytic activity and a much shorter sequence length (and less cost), it is a particularly attractive template around which to design novel antimicrobial peptides. However, the structure–activity relationship of it is still unknown. We designed and synthesized a series of C-terminal amidated analogs of BF-15 based on its amphipathic α-helix structure. And we characterized their antimicrobial potency and haemolytic activity. We identified the amidated BF-15 (analog B1) with potent antimicrobial activity against several antibiotic-resistant bacteria (MICs between 1 and 64 μg/mL, 2–16-folds higher than BF-30) and much lower haemolytic activity. The subsequent circular dichroism study results showed a typical α-helix pattern of analog B1 and the content of the α-helix structure of it increased significantly comparing with BF-30, which indicates the peptide sequence of BF-15 may provide a major contribution to the α-helix content of the whole BF-30 sequence. The peptide induced chaotic membrane morphology and cell debris as determined by electron microscopy. This suggests that the antimicrobial activity of B1 is based on cytoplasmic membrane permeability. Taken together, our results suggested that peptide B1 should be considered as an excellent candidate for developing therapeutic drugs.     

Effect of Ottoman Viper (Montivipera xanthina (Gray, 1849)) Venom on Various Cancer Cells and on Microorganisms

Cytotoxic and antimicrobial effects of Montivipera xanthina venom against LNCaP, MCF-7, HT-29, Saos-2, Hep3B, Vero cells and antimicrobial activity against selected bacterial and fungal species: Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, E. coli O157H7, Enterococcus faecalis 29212, Enterococcus faecium DSM 13590, Staphylococcus epidermidis ATCC 12228, S. typhimirium CCM 5445, Proteus vulgaris ATCC 6957 and Candida albicans ATCC 10239 were studied for evaluating the potential medical benefit of this snake venom. Cytotoxicity of venom was determined using MTT assay. Snake venom cytotoxicity was expressed as the venom dose that killed 50 % of the cells (IC₅₀). The antimicrobial activity of venom was studied by minimal inhibitory concentration (MIC) and disc diffusion assay. MIC was determined using broth dilution method. The estimated IC₅₀ values of venom varied from 3.8 to 12.7 or from 1.9 to 7.2 μg/ml after treatment with crude venom for 24 or 48 h for LNCaP, MCF-7, HT-29 and Saos-2 cells. There was no observable cytotoxic effect on Hep3B and Vero cells. Venom exhibited the most potent activity against C. albicans (MIC, 7.8 μg/ml and minimal fungicidal concentration, 62.5 μg/ml) and S. aureus (MIC, 31.25 μg/ml). This study is the first report showing the potential of M. xanthina venom as an alternative therapeutic approach due to its cytotoxic and antimicrobial effects.     

浙江蝮蛇蛇毒凝血酶在家兔体内的抗凝作用的研究

浙江产蝮蛇（Agkistrodon halys Pallas）毒类凝血酶经静脉注射家兔（0.25毫克/公斤）可使血浆凝血酶时间显著延长,这是由于血浆纤维蛋白原的水平下降及其性质上的变化引起的。表现在对Ristocetin的亲合力显著降低。此凝血酶时间之延长可被甲苯胺兰部分纠正。葡萄球菌猬集试验表明体内有大量纤维蛋白降解产物（FDP）产生。体外实验表明该酶不激活FXⅢ。 上述结果说明,类凝血酶的体内抗凝作用除由于纤维蛋白原含量降低及性质上有变化外,还与给药后体内大量纤维蛋白降解产物的形成有关。     

江西武夷山发现缅甸钝头蛇

2014年8月,在江西武夷山国家级自然保护区采集到3号蛇类标本,基于形态学比较,并结合线粒体细胞色素b基因（Cyt b）序列的分子系统关系重建,确定这3号标本为缅甸钝头蛇（Pareas hamptoni）,为江西省蛇类分布新记录种。     

湖北省发现灰腹绿蛇

2010年和2017年,在湖北省宜昌市兴山县采集到3条蛇类标本(2♀,1♂),经鉴定为灰腹绿蛇(Rhadinophis frenatus),为湖北省蛇类分布新记录种。标本均保存在湖北神农架森林生态系统国家野外科学观测研究站动物标本室。     

Molecular evolution of group II phospholipases A2

The nucleotide sequences of 13 cDNAs encoding group II phospholipases A₂ (PLA₂ ^S), which are from viperidae snake venoms and from mammalian sources, were aligned and analyzed by phylogenetic trees constructed using various components of the sequences. The evolutionary trees derived from the combined sequences of the untranslated (5 and 3) region and the signal peptide region of cDNAs were in accord with the consequences from taxonomy. In contrast, the evolutionary trees from the mature protein-coding region sequences of cDNAs and from the amino acid sequences showed random patterns. These observations indicated that the mature protein-coding region has evolved through a process differently from the untranslated and signal peptide regions. The trees built from the nucleotide differences at each of three positions of codons in the mature protein-coding region suggested that snakevenom-gland PLA₂ genes have evolved via a process different from mammalian PLA₂ genes. The occurrence of accelerated evolution has been recently discovered in Trimeresurus flavoviridis venom-gland group II PLA₂ isozyme genes (Nakashima et al. 1993, Proc Natl Acad Sci USA 90:5964–5968), so the present phylogenetic analysis together with the estimation of nucleotide divergence of cDNAs provides further evidence that snakevenom-group II PLA₂ isozyme genes have evolved by accelerated evolution to gain diverse physiological activities. Correspondence to: M. Ohno     

福建产圆斑蝰蛇毒中性磷脂酶A2的降压作用与机理

福建产圆斑蝰蛇毒中性磷脂酶Ａ２（ＰＬＡ２－３）对麻醉Ｗｉｓｔａｒ大鼠、猫和家兔均产生急性降压效应,并具快速耐受性。该降压作用能被吲哚美辛取消。应用放射免疫法测定血浆前列环素（其稳定产物６－ｋｅｔｏ－ＰＧＦｌａ）含量,与给药前相比,降压高峰时血浆６－ｋｅｔｏ－ＰＧＦＩｌａ含量增高。离体入胃网膜动脉条实验观察到,ＰＬＡ２－３呈剂量依赖性降低入胃网膜动脉条静息张力;对预先用去甲肾上腺素或５－羟色胺收缩的人胃网膜动脉条也具松弛作用。结果表明该ＰＬＡ２降压机制与前列环素（ＰＧＩ２）的释放和外周血管扩张有关。     

清栓酶治疗儿童脑动脉炎和脑血栓形成31例

用清栓酶治疗儿童脑动脉炎和脑血栓形成３１例,其中急性期２２例、恢复期５例、后遗症期４例,有效率分别为９Ｏ．９％、８０．０％和８７．１％．总有效率为８７．１％。脑动脉炎可导致血小板聚集性增高、血管闭塞和血栓形成,清栓酶可降低血小板聚集性,具有扩张血管,溶解血栓之作用,故可以使临床表现得以好转。     

游蛇科8种蛇的鳞片显微皮纹结构观察

游蛇科8种蛇,分别为云南沾益采集的棕网腹链蛇(Hebius johannis),云南铜壁关采集的卡西腹链蛇(H.khasiensis)、八线腹链蛇(H.octolineatum)、双带腹链蛇(H.parallela)、八莫过树蛇(Dendrelaphis subocularis),云南澜沧采集的大眼斜鳞蛇(Pseudoxenodon macrops),云南昆明采集的虎斑颈槽蛇(Rhabdophis tigrinus),云南临沧采集的中国小头蛇(Oligodon chinensis)。于2014年4月对其背鳞显微皮纹结构进行扫描电镜观察,8种蛇每种使用1个个体,每个个体分别从蛇体的前、中、近尾部各采集3枚鳞片,共观察9枚鳞片。低倍下观察到鳞棱,高倍下观察到纵行小棱、条索、横纹、小孔结构,这些结构存在种间差异。八莫过树蛇和中国小头蛇无鳞棱,但是其余6种蛇鳞棱十分明显;大眼斜鳞蛇的纵行小棱短于100μm,其余7种蛇的纵行小棱均长于100μm;仅八莫过树蛇和双带腹链蛇背鳞上有明显的条索结构;八莫过树蛇的横纹为平缓波纹,其余7种蛇的横纹为"U"形波纹;小孔的形状、排列位置在种间变化较大,小孔的密集程度以八莫过树蛇、大眼斜鳞蛇、虎斑颈槽蛇较高。在8种蛇中,八莫过树蛇背鳞的显微皮纹结构最为复杂,可能与其栖息在热带雨林中有关。     

Purification and Immunoprotection Evaluation of AaHIV from Complex Venom Metalloproteinases of Deinagkistrodon acutus

The aim of this study was to investigate the immunoprotective effects of AaHIV in mice. After purification, a 12% sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS‐PAGE) was performed. Bicinchoninic acid was used to determine the molecular weight and concentration of AaHIV. AaHIV, venom complex (VC), and phosphate buffered saline (PBS) were subsequently used to immunize the mice three times, and the blood was sampled 1 week after the third immunization to determine the serum immunoglobulin G (IgG) antibody titer. A skin‐bleeding inhibition assay and toxin‐eliminating assay were performed on the immunized mice. The purity and concentration of AaHIV were 86.6% and 1.20 mg/mL, respectively. The AaHIV group exhibited higher antibody titers than the VC group. The survival rate of the AaHIV group (7/10) was significantly higher than that of the PBS group (0/10) (P = 0.0031). The high titer of antibodies induced by AaHIV partially neutralized the bleeding activity of the Deinagkistrodon acutus venom complex.