基因工程改造生物合成肽类抗生素

许多微生物是以非核糖体方式合成生物活性肽。生物活性肽的合成以及它们的序列专一性是由一定数目按顺序排列的蛋白质模板所决定的。因此可以构建一种编码肽合成酶系的杂交基因，从而改变肽合成酶系对底物专一性。这里介绍一种两步重组法（twc-stepmethod）在基因水平取代相应的蛋白质模板中的一个氨基酸激活功能域。这种技术显示了将基因工程方法用于肽类抗生素生物合成的潜力。     

非核糖体肽合成酶结构研究进展

非核糖体肽合成酶(nonribosomal peptide synthetases,NRPS)是一类多功能蛋白质复合体,能识别、激活、转运氨基酸底物并按特定顺序合成非核糖体肽(NRPS)。NRPS构成天然生物活性产物的一大类,是细菌和霉菌等的次级代谢产物,具有结构多样性和重要的药用价值。目前发现的NRPS在微生物体内可能作为抗生素、铁载体、毒素、含氮物质的储存场所及调节生长等的信号分子等发挥各种功能[1],而其医药方面的开发应用主要集中于抗生素(如达托霉素)、抗癌药物(如博来     

尿苷肽类抗生素生物合成研究进展

尿苷肽类抗生素是一类具有相同母核结构的化合物,其化学结构独特、作用机制新颖、抗菌谱窄,是寻找新型低毒、窄谱抗菌药物的先导化合物或候选药物的最佳选择之一。本文介绍了尿苷肽类抗生素的化学结构特征以及构效关系,着重介绍了其生物合成机制的最新研究进展。尿苷肽类抗生素肽链的合成由非核糖体肽合成酶（non-ribosomal peptide synthetase,NRPS）以非线性机制催化完成,肽链的组装始于中心模块2,3-二氨基丁酸（2,3-diaminobutyric acid,DABA）,其后的延伸包括N端氨基酸或二肽与DABAβ-氨基间的缩合,以及C端的脲二肽与DABAα-氨基间的缩合。3′-脱氧-4′,5′-烯酰胺尿苷由尿苷经过3步反应转化而来,并在NRPS的催化下与四肽或五肽缩合形成尿苷肽类抗生素。尿苷肽类抗生素生物合成机制的阐明为利用组合生物合成技术获得新结构的尿苷肽类化合物奠定了基础。     

非核糖体肽合成酶主要结构域的研究进展

微生物的非核糖体肽合成酶(NRPS)可以催化合成众多结构多样的活性肽。NRPS组装链由多个模块组成，每个模块负责相应单体结合到新生肽的主链中，模块合成策略的核心为C—A—T三结构域单位。本文综述了与NPRS主要结构域相关的研究进展。     

非核糖体肽类化合物的组合生物合成策略研究进展

很多微生物能够利用非核糖体肽合酶合成结构复杂、种类繁多、生物活性多样的小分子肽类化合物.组合生物合成是对控制抗生素生物合成的基因簇进行阻断、置换、重组或异源表达等遗传操作,从而达到利用生物技术和环境友好的手段构建化合物衍生物库的目的.组合生物合成在增加天然活性化合物的数量,改良天然化合物的生物学活性,提高天然化合物的产量,开发创新药物和酶制剂等领域都具有重要应用价值.近年来,非核糖体肽的组合生物合成研究取得了重要进展.本文就非核糖体肽合酶的组合生物合成研究策略,从模块定点突变、替换、插入、删除、模块“洗牌”与异源表达等角度进行了综述.     

金属离子和磷酸盐对脂肽类抗生素FW99608生物合成的影响

不同金属离子和磷酸盐对脂肽类抗生素 FW996 0 8产生菌 Streptomyces sp.FIM996 0 8的发酵效价有不同影响。在有机发酵培养基中加入一定浓度 Cu2 +、Co2 +、Zn2 +以及 K2 SO4 能明显提高 Streptomycessp.FIM996 0 8的发酵效价并促进其菌丝生长。然而 ,Ca CO3和 K2 HPO4 · 3H2 O明显抑制脂肽类抗生素 FW996 0 8的生物合成。     

含硫多肽类抗生素那西肽的研究进展

那西肽（nosiheptide）是一类由活跃链霉菌（Streptomyces actuosus）产生的新型环保含硫多肽类抗生素。本文就其结构与理化特性,生物学功能及作用机制,生产,提取工艺,测定方法,安全性及应用等方面进行了综述,对产那西肽的结构基因,菌种改良方面的研究进行了总结,对那西肽后续的研究进行了展望。     

大环内酯类抗生素在呼吸疾病中的临床应用

大环内酯类抗生素（MA）是一类分子结构中具有12-16碳内酯环的抗菌药物的总称。其作用机制是通过阻断50s核糖体中肽酰转移酶的活性来抑制细菌蛋白质合成,属于快速抑菌剂。     

罗氏海盘车(Asterias rollestoni)中两种生物碱的分离纯化及其抗肿瘤活性研究

目的 从罗氏海盘车（Asterias rollestoni）中分离鉴定生物碱类天然产物,并进行体外抗肿瘤活性评价。方法 利用MCI GEL CHP20凝胶吸附树脂柱层析、硅胶薄层层析、硅胶柱层析、凝胶 Sephadex LH-20 柱层析和高效液相色谱等手段对化合物进行了分离纯化;运用NMR、MS等波谱方法并结合文献鉴定化合物的结构;采用SRB、MTT法评价化合物的抗肿瘤活性。结果 从罗氏海盘车的乙醇提取物中分离鉴定了1个环二肽生物碱类化合物 Fellutanine A （1）和1个吲哚生物碱N-（2-（1H-吲哚-3-基）乙基）-2-苯乙胺（2）。化合物1对MGC803细胞的抑制率为53.99%,具有一定的抗肿瘤活性。结论 两个生物碱类化合物均为首次从罗氏海盘车中分离获得,其中化合物1的发现说明罗氏海盘车中存在非核糖体肽合成酶,进一步研究其合成路线、从中分离非核糖体多肽合成酶可以为挖掘罗氏海盘车药用价值提供重要参考。     

Geldanamycin产生菌生物合成相关基因的克隆与分析

目的：从geldanamycin产生菌吸水链霉菌（S.hygroscopicus)中克隆生物合成基因，为阐明生物合成机制及改造其结构奠定基础。方法：以链霉菌／大肠埃希氏菌穿梭cosmids pKC505为载体构建了插入片段为20－30kb的S.hygroscopicus总DNA文库，以利福霉素中与3－氨基－5－羟基苯甲酸（AHBA）合成相关基因为探针，经菌落杂交，Southern杂交筛选同源基因片段，测序结果与Genbank进行同源性比较分析，并以attp-噬菌体载体KC515利用基因阻断实验对克隆的基因片段进行功能鉴定。结果：构建的基因文库含重组基因比率高，基因组覆盖率高，稳定性好，经同源基因探针杂交，从文库中筛选出9个阳性cosmids克隆pCGB20,pCGB26,pCGB28,pCGB29,pCGB36,pCGB45,pCGB49,pCGB63,pCGB75，测序分析表明，cosmid pCGB20中BamHI-BamHI 8kb片段两端的不完整ORF编码蛋白与竹桃霉素（oleandomycin)PKS Module 5,Module 6(一致性为79％）和红霉内酯合成酶ORF2（一致性为75％），ORF1（一致性为73％），ORF3（一致性为70％），高度同源；BamHI-BamHI 3kb片段一端与编码类结核分枝杆菌的磷酸吡哆醛依赖的氨基转移酶家族中半胱氨酸脱硫酶的DNA有同源性，该家族与AHBA合成酶关系密切，Cosmid pCGB20的BamHIBamHI 8kb及BamHI-BamHI 3kb基因片段已通过基因阻断实验初步鉴定，证明它们参与geldanamycin生物合成，而其他cosmids阳性克隆的序列分析及功能研究尚在进行中。     

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.     

Nachweis einiger Heilmittel in der Kniegelenksynovialflüssigkeit

Zusammenfassung Mittels Gaschromatographie und Dünschichtchromatographie wiesen die Autoren 11 Substanzen nach, welche durch Injektion oder nach Verabreichung per os in die Kniegelenksynovialflüssigkeit eindrangen. In ihrer Aufstellung konnten sie eine direkte Beziehung zwischen Struktur sowie chemischphysikalischen Eigenschaften der Substanz und ihrer Fähigkeit, aus dem Blut in die Kniegelenksynovialflüssigkeit einzudringen, nicht nachweisen, außer der Tatsache, daß Substanzen mit starker Affinität zu Eiweißstoffen erst in höheren Dosen nachweisbar waren.     

Lung disease and PKCs

The lung offers a rich opportunity for development of therapeutic strategies focused on isozymes of protein kinase C (PKCs). PKCs are important in many cellular responses in the lung, and existing therapies for pulmonary disorders are inadequate. The lung poses unique challenges as it interfaces with air and blood, contains a pulmonary and systemic circulation, and consists of many cell types. Key structures are bronchial and pulmonary vessels, branching airways, and distal air sacs defined by alveolar walls containing capillaries and interstitial space. The cellular composition of each vessel, airway, and alveolar wall is heterogeneous. Injurious environmental stimuli signal through PKCs and cause a variety of disorders. Edema formation and pulmonary hypertension (PHTN) result from derangements in endothelial, smooth muscle (SM), and/or adventitial fibroblast cell phenotype. Asthma, chronic obstructive pulmonary disease (COPD), and lung cancer are characterized by distinctive pathological changes in airway epithelial, SM, and mucous-generating cells. Acute and chronic pneumonitis and fibrosis occur in the alveolar space and interstitium with type 2 pneumocytes and interstitial fibroblasts/myofibroblasts playing a prominent role. At each site, inflammatory, immune, and vascular progenitor cells contribute to the injury and repair process. Many strategies have been used to investigate PKCs in lung injury. Isolated organ preparations and whole animal studies are powerful approaches especially when genetically engineered mice are used. More analysis of PKC isozymes in normal and diseased human lung tissue and cells is needed to complement this work. Since opposing or counter-regulatory effects of selected PKCs in the same cell or tissue have been found, it may be desirable to target more than one PKC isozyme and potentially in different directions. Because multiple signaling pathways contribute to the key cellular responses important in lung biology, therapeutic strategies targeting PKCs may be more effective if combined with inhibitors of other pathways for additive or synergistic effect. Mechanisms that regulate PKC activity, including phosphorylation and interaction with isozyme-specific binding proteins, are also potential therapeutic targets. Key isotypes of PKC involved in lung pathophysiology are summarized and current and evolving therapeutic approaches to target them are identified.     

Gender-related symptoms and correlates of alcohol dependence among men and women with a lifetime diagnosis of alcohol use disorders

This study explored gender-related symptoms and correlates of alcohol dependence in a crosssectional study of 150 men and 150 women with a lifetime diagnosis of alcohol use disorders (AUD). Participants were recruited in equal numbers from treatment settings, correctional centres and the general community. Standardized measures were used to determine participants' use of substances, history of psychiatric disorders and psychosocial stress, their sensation seeking and family history of substance use and mental health disorders. Multivariate analyses were used to detect patterns of variables associated with gender and the lifetime severity of AUD. Men had a longer history of severe AUD than women. Women had similar levels of alcohol dependence and medical and psychological sequelae as men, despite 6 fewer years of AUD. More women than men had a history of severe psychosocial stress, severe dependence on other substances and antecedent mental health problems, especially mood and anxiety disorders. There were differences in family history of alcohol-related problems approximating same-gender aggregation. The severity of a lifetime AUD was predicted by its earlier age at onset and the occurrence of other disorders, especially anxiety, among both men and women. The limitations in the generalizability of these findings due to sample idiosyncrasies are discussed.     

Biochemical and molecular characterisation of cubozoan protein toxins

Class Cubozoa includes several species of box jellyfish that are harmful to humans. The venoms of box jellyfish are stored and discharged by nematocysts and contain a variety of bioactive proteins that are cytolytic, cytotoxic, inflammatory or lethal. Although cubozoan venoms generally share similar biological activities, the diverse range and severity of effects caused by different species indicate that their venoms vary in protein composition, activity and potency. To date, few individual venom proteins have been thoroughly characterised, however, accumulating evidence suggests that cubozoan jellyfish produce at least one group of homologous bioactive proteins that are labile, basic, haemolytic and similar in molecular mass (42-46 kDa). The novel box jellyfish toxins are also potentially lethal and the cause of cutaneous pain, inflammation and necrosis, similar to that observed in envenomed humans. Secondary structure analysis and remote protein homology predictions suggest that the box jellyfish toxins may act as α-pore-forming toxins. However, more research is required to elucidate their structures and investigate their mechanism(s) of action. The biological, biochemical and molecular characteristics of cubozoan venoms and their bioactive protein components are reviewed, with particular focus on cubozoan cytolysins and the newly emerging family of box jellyfish toxins.     

Dose tolerability of chronically inhaled voriconazole solution in rodents

Invasive pulmonary aspergillosis (IPA) is a fungal disease of the lung associated with high mortality rates in immunosuppressed patients despite treatment. Targeted drug delivery of aqueous voriconazole solutions has been shown in previous studies to produce high tissue and plasma drug concentrations as well as improved survival in a murine model of IPA. In the present study, rats were exposed to 20 min nebulizations of normal saline (control group) or aerosolized aqueous solutions of voriconazole at 15.625 mg (low dose group) or 31.25 mg (high dose group). Peak voriconazole concentrations in rat lung tissue and plasma after 3 days of twice daily dosing in the high dose group were 0.85 ± 0.63 μg/g wet lung weight and 0.58 ± 0.30 μg/mL, with low dose group lung and plasma concentrations of 0.38 ± 0.01 μg/g wet lung weight and 0.09 ± 0.06 μg/mL, respectively. Trough plasma concentrations were low but demonstrated some drug accumulation over 21 days of inhaled voriconazole administered twice daily. Following multiple inhaled doses, statistically significant but clinically irrelevant abnormalities in laboratory values were observed. Histopathology also revealed an increase in the number of alveolar macrophages but without inflammation or ulceration of the airway, interstitial changes, or edema. Inhaled voriconazole was well tolerated in a rat model of drug inhalation.