蛇毒抗肿瘤蛋白化学成分的研究

对蛇毒抗肿瘤蛋白的化学成分进行研究。采用RP-HPLC分离蛇毒抗肿瘤蛋白各组分,收集纯化组分Ⅳ。非还原型SDS-PAGE和RP-HPLC鉴定组分Ⅳ的纯度;还原型SDS-PAGE与MALDI-TOF质谱仪测定组分Ⅳ的相对分子质量;测定组分ⅣN-末端氨基酸序列并进行Western blot鉴定;MTT法检测组分Ⅳ对体外培养的K562细胞的生长抑制作用。结果表明蛇毒抗肿瘤蛋白组分Ⅳ经SDS-PAGE和RP-HPLC分析为单一成分,MALDI-TOF质谱仪测得其相对分子质量为6714.22,其N-末端前5个氨基酸序列为L-K-C-N-K。经Western blot鉴定蛇毒抗肿瘤蛋白组分Ⅳ为细胞毒素,其对K562细胞的抑制作用呈明显的剂量依赖关系。     

乌苏里蝮蛇毒一种C-型凝集素相关蛋白的分离、纯化及活性测定

目的从乌苏里蝮蛇蛇毒中分离纯化得到具有促凝血活性的C-型凝集素相关蛋白。方法利用IDA-Sepharose FF亲和色谱作为独立的蛋白分离纯化手段,并且结合Sephadex G-100,Sephadex G-50凝胶过滤色谱从乌苏里蝮蛇蛇毒中分离得到一个新的蛋白组分。结果该组分经还原和非还原SDS-PAGE电泳鉴定结果显示为均一的单一条带,即C-型凝集素相关蛋白,相对分子质量约为15.7 kD。结论经过一系列的分离和纯化,能够从乌苏里蝮蛇蛇毒中提取到C-型凝集素相关蛋白组分。     

尖吻蝮蛇毒小分子多肽的分离及抗血小板聚集作用

目的从尖吻蝮蛇毒中分离纯化一种抗血小板聚集小分子多肽,研究其理化性质以及对ADP、胶原、凝血酶诱导的血小板聚集反应的影响。方法经SephadexG-75凝胶过滤,超滤,DEAE-SepharoseCL-6B离子交换层析法分离纯化蛇毒组分,采用高效液相鉴定纯度,用SDS-凝胶电泳(SDS-PAGE)测定其分子量,用比浊法测定其抗血小板聚集活性。结果从尖吻蝮蛇毒中分离相对分子质量约为7862u等电点为4.29的组分,该组分能抑制由ADP、胶原、凝血酶诱导的血小板聚集并成剂量依赖性。结论此法成功地从尖吻蝮蛇毒中纯化出抗血小板聚集组分。该组分与去整合素比较相似,可能属于去整合素家族。     

云南小狭口蛙促胰岛素释放肽的分离纯化与结构鉴定

通过葡聚糖Sephadex G-50凝胶过滤和反相高效液相析(RP-HPLC)等手段,对云南小狭口蛙(Callueslla yunnanensis Boulenger)皮肤分泌液进行分离纯化,得到了有促胰岛素释放活性的多肽分离峰.运用质谱仪测定该促胰岛素释放肽的相对分子质量为1 768.08,一级结构鉴定测得其氨基酸基...     

白唇竹叶青蛇(Trimeresurus albolabris)毒降纤酶的分离纯化以及性质

目的从白唇竹叶青蛇(T.albolabris)毒中分离纯化无出血作用的降纤活性组分,探讨其理化性质及部分生物功能。方法用DEAE-SephadexA-25,SephadexG-100和CM-SephadexC-50三步色谱法进行分离纯化。SDS-PAGE和HPLC鉴定其纯度和相对分子质量,平板法测定其降纤活性。结果从白唇竹叶青蛇毒中分离纯化获得单一的降纤组分,能迅速水解纤维蛋白原或纤维蛋白原Aα链,缓慢水解Bβ链,而对γ链无作用,SDS-PAGE鉴定其相对分子质量为56000。EDTA能抑制其纤维蛋白原水解活性,而PMSF、β-巯基乙醇对其活性无影响,提示该组分为单链α金属蛋白酶。结论从白唇竹叶青蛇毒中分离纯化得到1种无出血作用且降纤活性强的新蛇毒降纤酶。     

毕赤酵母表达重组hPK-5蛋白不均一性的鉴定

对毕赤酵母表达重组人纤溶酶原Kringle 5(hPK-5)蛋白的不均一性进行了鉴定.应用十二烷基硫酸钠聚丙烯酰胺凝胶电泳(SDS-PAGE)法及分子排阻高效液相色谱(SEC-HPLC)和反相高效液相色谱(RP-HPLC)进行纯度分析.采用糖蛋白染色法鉴定是否为糖蛋白.以Edman降解法测定N端氰基酸,采用高效液相色谱-电喷雾四极杆飞行时间质谱(HPLC-ESI-Q-TOF-MS)联用技术测定蛋白质精确分子质量.结果表明:SDS-PAGE测定为单一条带,纯度大于95%,SEC-HPLC测定为单一色谱峰,纯度大于95%,RP-HPLC测定为几个紧密相连的峰.糖蛋白染色为阴性.N端氨基酸测定结果表明含多个N端氨基酸.液质联用测定精确分子质量的结果表明hPK-5蛋白是相对分子质量分别为10 744.88,10 646.00,10 533.00和10 419.63的混合物.以上结果准确鉴定出毕赤酵母表达的该重组hPK-5蛋白是C端完整而N端依次缺失0～3个氨基酸的不均一蛋白.     

浙江眼镜蛇蛇毒中神经毒素的分离纯化及其镇痛作用研究

目的:研究浙江眼镜蛇(Najanajaatra)蛇毒的镇痛活性组分,为寻找镇痛效果好,而无成瘾性的新型镇痛药奠定基础.方法:通过两次CM-SephadexC-25和一次SephadexG-50柱层析对眼镜蛇毒进行了分离纯化.采用PAGE法对分离纯化后的眼镜蛇神经毒素(cobroneurotoxin,CNT)纯度进行鉴定;以SDS-PAGE法测定CNT的分子量;等电聚焦法(Isoelectrofocusing,IEF)测定CNT的等电点;以Lowry法测定其蛋白含量;用醋酸扭体法、热板法与电刺激法考察CNT的镇痛活性并通过测定LD50考察其毒性.结果:眼镜蛇毒经3次柱色谱后,CNT经鉴定为单一组分.经SDS-PAGE法测定其分子量为7000,等电点为10.2,蛋白含量为92%.CNT能显著降低小鼠对化学刺激与电刺激的敏感性;小鼠痛阈百分率的提高可达51.3%,并呈一定的量效关系;小鼠腹腔注射的LD50为81μg·kg-1,95%可信限为58～104μg·kg-1.结论:眼镜蛇毒经3次柱色谱后得到具有镇痛活性的单一组分(CNT).     

舟山眼镜蛇毒蕈碱样多肽MP的部分理化性质测定

目的对舟山眼镜蛇毒蕈碱样多肽MP成分进行纯化及部分理化性质测定。方法采用色谱技术纯化蛇毒MP成分,质谱仪测定其相对分子质量(Mr);Edman降解法分析部分氨基酸序列,与已知成分比对;以卵磷脂为底物测定MP组分的磷脂酶A2活性;采用Bliss法测定MP对小鼠的急性毒性。结果 MP的Mr为13 260,其N端16位氨基酸序列为NLYQFKNMIQCTVPSR,与已知蛇毒磷脂酶A2基本一致,并具有较强的磷脂酶A2活性;腹腔注射MP对小鼠的LD50值为14.3 mg/kg。结论 MP为一种眼镜蛇毒磷脂酶A2。     

SDS-聚丙烯酰胺凝胶电泳法测定蛇毒抗瘤蛋白的相对分子质量

目的建立改进的低分子SDS 聚丙烯酰胺凝胶电泳法测定蛇毒抗瘤蛋白的相对分子质量 (Mr)。方法考察不同因素对电泳结果的影响 ,对Mr 标准进行直线回归分析 ,确定蛇毒抗瘤蛋白中组分的Mr。结果测得各条带的Mr 分别为 :2 35 0 0、15 4 0 0、1340 0、1130 0、930 0、80 0 0。结论此法供试品处理方便 ,用量少 ,在含 6mol/L尿素的分离胶 (交联度为 16 .5 % ,丙烯酰胺总浓度为 6 % )中能同时显示中、低Mr 的条带 ,是一种测定中、低Mr 的较好方法。     

白眉蝮蛇降纤酶的纯化及特性分析

目的从白眉蝮蛇蛇毒中提取降纤酶,并对其进行特性分析。方法采用一步亲和色谱法分离纯化降纤酶,用高效液相色谱分析其纯度,SDS-PAGE测定其相对分子质量。结果分离得到的降纤酶纯度高(99%以上),SDS-PAGE分析为一条带,相对分子质量为36 000,比活性为4 800 u/mg。结论用一步亲和色谱法从白眉蝮蛇蛇毒中纯化降纤酶的方法简单有效,所得产品纯度高、产量高。     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.