麦迪霉素高产菌株的筛选

通过紫外线和紫外线-咖啡因对生米加链霉菌1748变株进行处理,筛选出5株产麦迪霉素高产菌株。经紫外线照射40sec和50sec并加500μg/ml咖啡因处理所产生的变异菌株比原株产量提高30%,且稳定。我们还研究了变异菌株的形态与产量的关系。     

链霉素抗性突变理性筛选avermectin高产菌株

为提高菌株avermectin的产量，本文以链霉素抗性为选择压力，对除虫链霉菌Streptomyces avermi-tilis进行紫外诱变（253.7nm,30w，照射时间45s)，得到在摇瓶发酵水平比出发菌株产量提高25%以上的4株突变株，其中2株提高水平达30%以上，实验表明了链霉素抗性突变与产抗生素突变之间的密切联系。同时，对其机理和意义作了一些探讨。     

西罗莫司高产菌株与野生菌株中FKBP25的初步比较

目的　对比西罗莫司高产突变菌株———吸水链霉菌R2 7、R388、R4 4 1和野生菌株———吸水链霉菌ATCC 36 7817的蛋白质电泳图谱及FKBP2 5含量的差异 ,探讨FKBP2 5与西罗莫司产量的可能关系。方法　制备、分离高产突变株与野生菌株的菌体蛋白质并进行PPIase活性测定 ,比较 3株西罗莫司高产突变株与野生菌株的蛋白质电泳图谱及PPI ase酶活性。结果　西罗莫司低产的野生菌株的FKBP2 5含量比西罗莫司高产突变菌株高。结论　初步认为在吸水链霉菌中西罗莫司的产量与FKBP2 5量的多寡呈现一定的相关性     

原生质体诱变及高通量筛选选育链霉素高产菌株

目的 通过诱变和筛选方法的研究，提高灰色链霉菌(Streptomyces griseus)生产链霉素的水平。方法 优化灰色链霉 菌的原生质体的生成和再生条件，并对得到的原生质体进行紫外诱变，然后利用微孔板高通量方式对获得菌株进行筛选。结果 经过诱变选育获得一株菌NP-11703，其链霉素产量在100L罐上比出发菌株提高了21.8%。结论 用紫外诱变原生质体，可以有 效提高灰色链霉菌产链霉素的能力。结合高通量筛选模型的应用，可大大加快高产菌株的筛选效率。     

龟裂链霉菌工业菌中zwf1基因的阻断对土霉素生物合成影响

目的运用代谢工程手段对龟裂链霉菌工业菌(Industrial Streptomyces rimosus,SRI)进行基因改造,提高土霉素(oxytetracycline,OTC)产量。方法利用pKC1139质粒阻断SRI基因组中葡萄糖-6-磷酸脱氢酶(glucose-6-phosphate dehydrogenase)编码基因zwf1。结果筛选得到一株OTC高产突变株,将突变株与原始菌株进行发酵,发现OTC产量比原始菌株提高了36.2%。结论 SRI基因组中zwf1基因的缺失使细胞合成土霉素的能力增强;龟裂链霉菌中初级代谢关键基因调控会影响次级代谢。     

通过阻断GntR家族调控基因ygrA挖掘海洋链霉菌Streptomyces sp. OUC6819中抗MDR菌活性次级代谢产物

激活南海红树林来源链霉菌Streptomyces sp.OUC6819菌株中不表达或表达量低的隐性生物合成基因簇,挖掘具有优良多重耐药菌（MDR）抗菌活性的次级代谢产物。方法 通过生物信息学分析推测Streptomyces sp.OUC6819基因组中可能的GntR家族调控子,采用PCR-targeting策略敲除其中的ygrA基因,HPLC分析突变株和野生株的发酵产物的差异,并比较粗提物对5株MDR菌抑制活性。结果 HPLC分析结果表明与野生株相比,突变株中化合物1和化合物2产量分别产量提高了9倍和7倍;突变株发酵液粗提物对其中3株MDR菌抑制活性较野生株明显提高。结论 通过阻断GntR家族调控子ygrA激活了Streptomyces sp.OUC6819菌株中具有抗MDR菌活性次级代谢产物合成基因簇的表达,为从中发掘新的抗MDR菌抗生素奠定了必要基础;同时,将为其他海洋链霉菌中隐性基因簇的激活提供重要参考。     

离子注入诱变育种技术在柔红霉素高产菌德育中的应用

应用低能N^ 离子对柔红霉素产生菌天蓝淡红链霉菌SIPI 1482野生型菌株的孢子进行注入诱变选育，获得了柔红霉素产抗能力提高15倍的高产突变株。与亲株的菌落形态比较发现，高产突变株SIPI 1482M2的菌落形态发生较大的变化。     

离子注入诱变育种技术在柔红霉素高产菌选育中的应用

应用低能N+离子对柔红霉素产生菌天蓝淡红链霉菌SIPI1482野生型菌株的孢子进行注入诱变选育,获得了柔红霉素产抗能力提高15倍的高产突变株.与亲株的菌落形态比较发现,高产突变株SIPI1482M2的菌落形态发生较大的变化.     

60Coγ射线对南昌霉素产生菌的诱变选育

采用不同剂量的^60Coγ射线，对南昌霉素产生菌南昌链霉菌80-5.3-116菌株的孢子进行处理。结果表明，7.74c/kg的诱变剂量在对孢子致死率为90％左右时，具有较好的诱变效应；初筛摇瓶产量正变率达到21.08％；复筛摇瓶发酵效价比出发菌株提高50％以上的有10株，占初筛菌株的5％；连续四批摇瓶发酵试验平均产量比出发菌株的产量提高50％以上；有6个菌株摇瓶产量分别比出发菌株提高60％，其中3株平均摇瓶产量比出发菌提高70%以上。     

复合诱变法选育普那霉素高产菌株

以始旋链霉菌(Streptomyces pristinaespiralis)ZP2为出发菌株,经紫外线(UV)、亚硝基胍(NTG)复合诱变,并结合普那霉素抗性突变株的理化筛选,选育到一株高产突变菌株UN2056,其普那霉素产量达到1490 mg/L,比出发菌株提高了45.7%.传代试验表明该高产突变菌株的高产性能遗传特性稳定.高产突变株UN2056在5 L发酵罐中进行发酵试验,其平均发酵产量达到1645 mg/L,比出发菌株提高了60.8%.     

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.

---

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.     

Synthesis,Cytotoxicity and Antileishmanial Activity of Some N-(2-(indol-3-yl)ethyl)-7-chloroquinolin-4-amines

We report herein the condensation of 4,7-dichloroquinoline (1) with tryptamine (2) and D-tryptophan methyl ester (3) . Hydrolysis of the methyl ester adduct (5) yielded the free acid (6) . The compounds were evaluated in vitro for activity against four different species of Leishmania promastigote forms and for cytotoxic activity against Kb and Vero cells. Compound (5) showed good activity against the Leishmania species tested, while all three compounds displayed moderate activity in both Kb and Vero cells.     

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.     

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.     

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.