TOXIN EVOLUTION IN SCORPION VENOM: EVIDENCE FOR TOXIN DIVERGENCE UNDER STRONG NEGATIVE SELECTION IN LEIURUS QUINQUESTRIATUS SUBSPECIES

The Buthid scorpion Leiurus quinquestriatus is divided into two sub-species whose region of contact occurs at the Suez Isthmus. L.q. quinquestriatus, found in the North Africa is distinguished from L.q. hebraeus by minor differences in morphology. Despite the very high similarity in body plan, out of the 24 toxins isolated from this species none is common to both sub-species, suggesting a degree of molecular divergence not apparent at the morphological level. We show, by comparison with two sets of reference proteins from humans and Old-World monkeys, that divergence of toxins with common structures and functions in these two sub-species has occurred under conditions of strong negative selection. Potential selection pressures responsible for toxin divergence are discussed, including the role of conflicting interests during courtship.     

眼镜王蛇毒组分Ⅶ-2的纯化及其毒性鉴定

眼镜王蛇毒用CM-Sephadex C-25柱层析、醋酸铵缓冲液洗脱,获得20个蛋白组分。Ⅷ峰经CM-C 32重层析后获得组分Ⅷ-1与Ⅷ-2,组分Ⅷ-2经Sephadex G-50滤过后呈单一吸收峰。用三种不同类型的聚丙烯酰胺凝胶电泳鉴定组分Ⅷ-2为电泳纯蛋白。分子量为7,827;等电点约为pH 7.6。小鼠ip LD₅₀为0.155 mg/kg(0.146～0.165 mg/kg)。用离体小鸡颈二腹肌标本表明组分Ⅷ-2是属于突触后神经毒,其阻断作用在反复冲冼6小时内是相当难逆转的。从氨基酸组成测定结果的分析、分子量、双向免疫扩散、LD₅₀的比较以及阻断神经肌肉传递的难逆转性,可推测眼镜王蛇毒组分Ⅷ-2是与α-银环蛇毒素相似的难逆转性长链突触后神经毒素。     

蛇床果实中香豆素类成分的变异及其规律

目的:探讨蛇床果实种内香豆素成分的变异与地理分布的关系及其变异规律。方法:用毛细管GC 法对蛇床果实48 个居群59 个样品中蛇床子素、佛手柑内酯、欧前胡素、O-乙酰哥伦比亚苷元等9 个香豆素成分进行含量测定与定性分析。结果与结论:根据蛇床果实中香豆素成分化学结构的差异及各成分的有无与含量的高低结合地理分布,可将蛇床分为3 个类型,即化学型I:以蛇床子素和线型呋喃香豆素为主要成分;分布于福建、浙江、江苏等亚热带常绿阔叶林区域。化学型II:以角型呋喃香豆素为主要成分;分布于辽宁、黑龙江、内蒙古等温带针阔叶混交林区域。化学型III:蛇床子素、线型和角型呋喃香豆素同时存在,属于混合的过渡类群;分布于河南、河北、山西等暖温带落叶阔叶林区域的过渡地带。     

辽宁产东亚钳蝎毒中哺乳动物毒素Ⅲ的分离纯化及部分性质的研究

采用 CM—Sephadex C—50,SP—Sephadex C—25离子交换柱层析和 SephadexG—50凝胶过滤三步分离程序,从东亚钳蝎毒中得到一种新的哺乳动物毒素。经低 pH 系统不连续聚丙烯酰胺凝胶园盘电泳,SDS—不连续聚丙烯酰胺凝胶板电泳及等电聚焦聚丙烯酰胺凝胶园盘电泳鉴定说明该毒素为电泳纯的蛋白质。用 SDS 电泳法测得其分子量为8,750道尔顿,等电聚焦电泳法测定 pH 为8.2。纯化成份的产率为2.5%。     

东亚钳蝎毒及其成分抗癫痫肽对心脏和血管的作用

本文报告河北产东亚钳蝎(Buthus martensii Karsch)毒及用柱层析法从粗毒中纯化的抗癫痫肽对心脏、血管的作用。实验结果证明蝎毒能使麻醉免LVP、左室dp/dt升高、心率稍减慢;心得安能对抗蝎毒升高LVP和dp/dt的作用。抗癲痫肽对LVP、dp/dt、心率的影响都不明显。蝎毒使离体豚鼠心脏收缩张力增强,心率减慢,并呈现频繁的心律不齐。心得安能对抗蝎毒增强心脏收缩张力的作用,但不能消除心律不齐。抗癫痫肽使心肌收缩张力下降,心率加快,同时也引起心律不齐。蝎毒能引起兔主动脉条明显收缩,作用强度约为NE的1/5,在蝎毒作用的基础上,妥拉苏林使收缩曲线升高,心得安使曲线降低。抗癲痫肽使兔主动脉条轻微松弛。用光电容积搏动法实验,蝎毒和抗癲痫肽都能使小鼠末稍血管收缩。     

LOCATION OF DISULFIDE BRIDGES IN CARDIOTOXIN FROM THE VENOM OF FORMOSAN COBRA (NAJA NAJA ATRA)

The location of the four disulfide bridges in cardiotoxin from the venom of the Formosan cobra, Naja naja atra, was determined by isolating cystine-containing peptides from the enzymic and partial acid hydrolyzates of the intact toxin. The results indicate that the disulfide bridges are formed by half cystine residues 3–21, 14–38, 42–53, and 54–59. The amino acid sequence at the position 48–49 was revised to -Leu-Val- instead of -Val-Leu- as reported previously.     

眼镜蛇神经毒素的镇痛作用

眼镜蛇神经毒素(NT)在小鼠热板及大鼠电尾嘶叫测痛模型,都显示出明显的镇痛作用,并有剂量-效应关系。注射NT 0.022mg/kg,2h后,大鼠痛阈出现显著上升,3h后达到较佳效果,并能保持其效应强度达24h。连续给小鼠注射NT 0.023mg/kg,持续9d,小鼠并不产生耐受现象。结果提示,NT的镇痛机理可能与吗啡不同。     

Isolation and cloning of exendin precursor cDNAs from single samples of venom from the Mexican beaded lizard (Heloderma horridum) and the Gila monster (Heloderma suspectum).

Reptile venoms are complex cocktails of bioactive molecules, including peptides. While the drug discovery potential of most species remains unrealized, many are endangered and afforded protection under international treaties. In this study, we describe how potential clinically important bioactive peptides and their corresponding mRNAs can be structurally characterized from single, small samples of reptile venom. The potential type-2 diabetes therapeutics, exendin-3 and exendin-4, from the Mexican beaded lizard (Heloderma horridum) and the Gila monster (Heloderma suspectum), respectively, have been characterized at both protein and nucleic acid levels to illustrate the efficacy of the technique and its contribution to biodiversity conservation.     

SOME BIOCHEMICAL RESPONSES OF RAT SKELETAL MUSCLE TO A SINGLE SUBCUTANEOUS INJECTION OF A TOXIN (NOTEXIN) ISOLATED FROM THE VENOM OF THE AUSTRALIAN TIGER SNAKE NOTECHIS SCUTA TUS SCUTA TUS

1. Some biochemical responses of mammalian skeletal muscle to a single subcutaneous injection of a purified toxin from the venom of the Australian tiger snake, Notechis scutatus scutatus, have been investigated to determine the role of changes in peptide hydrolase enzymes in the muscle wasting caused by notexin administration. 2. Within 6 h of injection, serum creatine kinase activity was increased by five-to ten-fold, and remained elevated for at least 24 h. 3. There was an initial inflammatory response in the muscle adjacent to the site of injection; by 12 h after injection, muscle wet weight increased by 60%. 4. After the initial increase, wet weight fell to about 50% of normal at 7 days. Normal wet weight was achieved by 20 days after the injection. Over the period 1–20 days after the injection of the toxin, the changes in wet weight were mirrored by changes in non-collagen protein content. 5. The activities of cathepsin B and acid proteinase were increased following the injection of the toxin. By 2 days after injection, there was a ten-fold increase in the activity of cathepsin B, and a seven-fold increase in the activity of acid proteinase. The activity of both enzymes became normal by 20 days. 6. Experiments utilizing a variety of cytotoxic drugs suggested that the acid proteinase and cathepsin B are primarily located within invading phagocytic cells. 7. The results are discussed with reference to the previously described pathology of toxin-damaged skeletal muscle.     

3,4-二羟基苯乙酮(DHAP)对离体心肌电活动和机械活动的作用

The effects of DHAP on electrical and mechanical activities were investigated by synchronously recording action potential and isometric tension in isolated myocardium. No influence was demonstrated on action potential (APA, APD₂₀、APD₉₀) by DHAP 10^-5～10^-3M in guinea pig palillary muscle. The inhibition on the force of contraction with the same concentration of DHAP, however, was shown in a concentration-dependent way. The effects of DHAP on the electrical and mechanical activities in cat papillary muscle were similar to those in guinea pig papillary muscle. With the dose of DHAP 10^-5～5×10^-4M, alteration of action potential of pacemaker cells was not observed in the isolated sinus node preparation of the rabbit. When the dosage was increased to 10^-3 M, the electrical activities were inhibited. The experimental results indicate that the effects of a certain dose of DHAP on inhibiting the tension in myocardium are available in clinical application. A warning is given that an increase in dosage may enhance the inhibition on contractile force in myocardium and inhibit the automaticity of sinus node pacemaker cells.     

前胡丙素对高血压大鼠血管肥厚、细胞内钙、胶原及NO的影响

目的　研究前胡丙素对自发性高血压大鼠SHR及肾型高血压大鼠RHR的血管肥厚、细胞内钙、胶原、NO及血管收缩的反应性影响。方法用显微测微仪测定血管中膜层厚度,细胞大小,用Fura-2/AM为荧光指示剂,测定单细胞内［Ca²⁺］i,以测定羟脯氨酸含量反映胶原含量,用Griess法测定NO含量,以血管环观察收缩反应。结果　前胡丙素抑制血管中膜层增厚,维持细胞内［Ca²⁺］i稳态。减少胶原形成,增加SMCs释放NO。抑制血管环高反应状态。结论　前胡丙素抑制高血压血管肥厚,降低胶原含量及血管异常反应。     

3,4-二羟基苯乙酮(DHAP)对离体心肌电活动和机械活动的作用

3,4-二羟基苯乙酮(DHAP)是禿毛冬青叶中有效成分。临床用于冠心病患者,对心绞痛及部分患者的心律失常有一定缓解作用。整体动物实验表明,DHAP能扩张全身动脉,降低心脏后负荷,增加冠脉血流量。此作用可能为DHAP临床效应的作用机理之一。DHAP对心肌细胞直接作用的研究很少。范世藩报道DHAP 0.5～1mg/ml(相当于3.5～     

海蛇提取物对实验性贫血小鼠红细胞及血红蛋白的影响

采用皮下注射乙酰苯肼造成小鼠溶血性血模型，以生大黄煎剂灌胃制备小鼠血虚模拟，观察了哈氏平颏海蛇乙醇提取物对两种贫血模型小鼠红细胞数及血红蛋白含量的影响。     

曲匹地尔对培养大鼠血管平滑肌细胞的有丝分裂素激活蛋白激酶(MAPK)和P34~(cdc2)激酶的影响

目的：研究曲匹地尔（Ｔｒａ）对培养大鼠主动脉血管平滑肌细胞的细胞增殖周期及对有丝分裂素激活蛋白激酶（ＭＡＰＫ）和Ｐ３４ｃｄｃ２激酶的表达及活性的影响。方法：以流式细胞术测定细胞周期,免疫印迹法测定ＭＡＰＫ和Ｐ３４ｃｄｃ２的表达,免疫沉淀后测定ＭＡＰＫ和Ｐ３４ｃｄｃ２对其特异性底物髓脂质碱性蛋白（ＭＢＰ）和ＨｉｓｔｏｎｅＨ１的磷酸化活性。结果：Ｔｒａ降低细胞周期中Ｓ期比例和细胞分裂增殖指数,能明显抑制给血清刺激后ＭＡＰＫ的表达和活性,明显抑制Ｐ３４ｃｄｃ２激酶活性而对其表达无明显影响。结论：Ｔｒａ对细胞周期的影响与其抑制ＭＡＰＫ和Ｐ３４ｃｄｃ２激酶活性和ＭＡＰＫ的蛋白表达有关。     

曲匹地尔对培养大鼠血管平滑肌细胞的有丝分裂素激活蛋白激酶(MAPK)和P34cdc2激酶的影响

目的：研究曲匹地尔(Tra)对培养大鼠主动脉血管平滑肌细胞的细胞增殖周期及对有丝分裂素激活蛋白激酶(MAPK)和P34^cdc2激酶的表达及活性的影响。方法：以流式细胞术测定细胞周期,免疫印迹法测定MAPK和P34^cdc2的表达,免疫沉淀后测定MAPK和P34^cdc2对其特异性底物髓脂质碱性蛋白(MBP)和Histone H1的磷酸化活性。结果：Tra降低细胞周期中S期比例和细胞分裂增殖指数,能明显抑制给血清刺激后MAPK的表达和活性,明显抑制P34^cdc2激酶活性而对其表达无明显影响。结论：Tra对细胞周期的影响与其抑制MAPK和P34^cdc2激酶活性和MAPK的蛋白表达有关。     

斑海马提取物抗大鼠血栓形成的作用及成份分析

对斑海马甲醇提取物抗血栓作用的研究结果表明，ＥＨＴ能明显抑制大鼠生颈动脉血栓和大鼠脑血栓的形成，提示ＥＨＴ具有明显血栓作用，其有效成份为多种不饱和脂肪酸。     

大丁草中抗菌活性成分的研究(Ⅲ)——大丁甙在大白鼠体内、外的代谢研究

本文报道了大丁甙在大鼠体内、外的代谢研究。通过对大鼠胃液和肠内容物的培养,证明大丁甙在大鼠的消化道内发生了转化,并鉴定了主要代谢物的结构。发现4-羟基香豆精在体内的一种新代谢途径。对灌胃给药的大鼠尿及粪便的研究也证明了代谢物的存在。由于代谢产物在体外呈抑菌活性,从而证明大丁甙在动物体内经过代谢,转化成代谢产物而发挥抑菌活性。该研究为今后更好地应用大丁草提供了理论依据。     

BETA-ADRENOCEPTOR-MEDIATED EFFECTS OF CLENBUTEROL (NAB 365) ON TRACHEA, HEART AND SKELETAL MUSCLE IN ANAESTHETIZED GUINEA-PIGS

1. Intravenous injection of clenbuterol (NAB 365) in anaesthetized guinea-pigs produced decreases in tracheal segment pressure and in soleus muscle contractions and a slight increase in heart rate. These responses were reduced by propranolol. 2. Clenbuterol was less potent than isoprenaline on the trachea and soleus muscle and even less potent on the heart. The maximum response to clenbuterol was the same as that to isoprenaline on the trachea and the soleus muscle but it was not more than 30% of that to isoprenaline on the heart. There was no significant difference between the potencies of clenbuterol on the trachea and the soleus muscle. 3. The onset of the responses to clenbuterol were slower and the duration of action longer than those to isoprenaline. 4. High doses of clenbuterol blocked isoprenaline responses on heart rate. 5. Clenbuterol showed selectivity for the trachea and the soleus muscle (β₂-adrenoceptors) as compared with the heart (β₁-adrenoceptors). This could result, at least in part, from its partial agonist activity on the heart.     

三七中人参三醇甙对动物缺血性心律失常的影响

三七中人参三醇甙(简称PTS)能明显对抗大鼠结扎冠状动脉诱发的缺血性心律失常及再灌注性心律失常,并可使缺血再灌注引起的心肌梗塞范围明显缩小。对iv CaCl₂-Ach引起的小鼠房颤或房扑也有明显的保护作用。PTS还可明显延长小鼠在常压缺氧条件下的存活时间。     

EFFECTS OF ISOPRENALINE, LEVODOPA AND A PHOSPHODIESTERASE INHIBITOR (ICI 63,197) ON CYCLIC AMP LEVELS AND CONTRACTIONS OF SOLEUS MUSCLES IN ANAESTHETIZED CATS

1. Cyclic AMP levels have been determined in the soleus muscles of anaesthetized cats in the absence of drugs, and during depression of incomplete tetanic contractions produced by (-)-isoprenaline, ICI 63,197 (a phosphodiesterase inhibitor) or levodopa. 2. Cyclic AMP levels were elevated at the peak of tension depression produced by isoprenaline. Effects of isoprenaline on cyclic AMP and on contractions were dose dependent and statistically significantly related one to the other. Both effects were blocked by propranolol. 3. ICI 63,197 and levodopa produced isoprenaline-like effects on contractions but times to peak effect and recovery were longer. Cyclic AMP levels estimated during the depressant action were elevated. 4. The results support the involvement of cyclic AMP in the depressant effect of beta-adrenoreceptor agonists on slow-contracting mammalian skeletal muscle.