新肽类抗生素B—3543的研究 Ⅰ.产生菌的分类鉴定及生物学特性

从中国武汉地区水稻白叶枯病叶上分离出一株真菌B-3543,它产生一种新的肽类抗生素,对多种革兰氏阳性和阴性细菌有抗菌活性。其中,对水稻白叶枯病菌抗菌作用最强,其最低抑菌浓度为0.2μg/ml。根据该菌株的形态特征、培养特征和生理特性,鉴定为桃色拟青霉B-3543菌株。     

稻白叶枯病黄叶型症状的发生与菌株及品种的关系

本试验初步明确水稻白叶枯病黄叶型症状的发生与病原菌的致病力以及水稻品种的感病性有密切的关系。相关系数均达到极显著水准。凡致病力强的菌株(Ⅳ、Ⅴ群)侵染感病的品种,一般都容易发生黄叶型症状,而致病力中和弱的菌株(Ⅲ、Ⅱ、Ⅰ群)浸染感病的品种,或致病力强的菌株浸染抗病的品种,都不会发生黄叶型症状。     

溢脓法筛选模型的应用及农用抗生素Bo-10药效研究

溢脓法筛选模型是1981年发表的筛选防治水稻白叶枯病菌(Xanthomonas oryzae)抗生素有效菌株的一种室内初筛与测定方法。我们应用此模型筛选得到一株链霉菌,编号为Bo-10(Streptomyces Bo-10),该菌株产生的抗生素Bo-10,对多种植物病原真菌如柑桔青霉(Penicillium italicum)、柑桔绿霉(Penicillium digitatum)、水稻纹枯病菌(Pellicularia sasakii)等具有较强的抑制作用,同时,对一些常见农作物病害,如黄瓜白粉病(Sphaerotheca fuligenea)具有较好的治疗效果。对抗生素Bo-10在植物组织内吸、传导作用性能也作了一定的探讨。本文将1981至1982年间研究工作的初步结果报告如下:     

木麻黄组织抽提物对青枯菌生长的抑制作用及其与抗病性的关系

木麻黄(Casuarina sp.)组织的乙醇抽提物在琼脂平板上能抑制青枯菌(Pseudomonassolanacearum)生长,抗病品系粗提物的抑菌活性均比感病品系粗提物的抑菌活性高。小枝粗提物的抑菌活性较高,茎皮层、根粗提物的次之,茎木质部粗提物的较低。接种青枯菌后15天内粗提物抑菌活性无显著变化。小枝粗提物不仅对6个青枯菌株的生长有抑制作用,对水稻白叶枯菌(Xanthomonas campestris Pv.Oryzae)的生长也有显著抑制作用,对柑桔溃疡病菌(Xanthomonas citri)的生长只有微弱抑制作用。初步化学分析表明粗提物成分包括有机酸、酚类、丹宁、还原糖、黄酮类和蒽醌类等物质,其中黄酮类是主要抑菌成分。     

抗菌肽作用机制及应用研究进展

在这抗生素耐药性病菌不断出现的时代,新型抗菌药物的发现已迫在眉睫。而抗菌肽为大多数生物对入侵病原体的自然防御系统的重要组成部分,具有独特的抗菌作用机制,迅速杀菌且不易引发细菌的耐药性,可单独或与抗生素联合使用杀伤病原体,是一类极具发展潜力的生物药物。本文根据抗菌肽的理化性质,作用机制及抗菌肽的设计等进行综述,并对几种有前景的抗菌肽作一简单介绍。     

水稻白叶枯病抗原与病原间互作效应的研究

以水稻白叶枯病病原细菌(Xanthomonas campestris PU.Oryzas)的41个菌株,对9个水稻品种作抗病性鉴定。利用Tai氏所提供的分析方法,估测和分析各供试品种及病原菌株遗传型稳定性参数。试验结果表明:抗原品种与病原菌株之间存在很显著的互作。根据平均病级及抗病性稳定性程度,把水稻品种划分为8个类型,还根据致病力的强弱及致病性的稳定性的程度,把病原菌株划分为6个类群。本文对水稻白叶枯病抗病性鉴定中的“标准鉴别品种”应具备的条件提出初步意见。还从供试菌株中筛选出一套具有稳定致病力的鉴别菌株。     

合成抗菌肽P18及其截短肽的结构和杀真菌活性

P18(KWKLFKKIPKFLHLAKKF-NH2)是从一个具有强抗菌活性、但对人红血球无溶血作用的杀菌肽A-爪蟾抗菌肽2杂合体出发而设计的一段抗菌肽。P18对致病真菌白色假丝酵母、白吉利丝孢酵母、黄曲霉和尖孢镰孢有杀灭活性(MIC:12.5～25mm)。中心的Pro9残基和P18的全序列对其杀真菌活性是必需的。圆二色性分析表明,这类肽段中a-螺旋含量的提高与杀真菌活性的增强并无关联。合成抗菌肽P18及其截短肽的结构和杀真菌活性@龚家玮     

百日咳杆菌单克隆抗体的分离与鉴定

百日咳杆菌的组分及产物甚多,其中不少都与该菌的致病力或免疫保护性有密切关系,除脂多糖(LPS)外,非致病性百日咳菌株往往没有这些成份。为确切了解诸成份与致病力及免疫原性的关系,作者采用改良的     

卡介苗接种并发混合感染一例

正卡介苗是一种减毒活菌苗,对人无致病力,却可使机体产生较强的免疫力,临床的应用证明,卡介苗保护了无数儿童免受结核病菌感染,接种不当也会产生不良反应。1病例资料患儿,男,1岁。接种卡介苗1月后在注射部位出现大小约2cm×3cm包块,颜色稍红,触诊有波动感,皮温较周边高,末出现全身发热、盗汗、消瘦等全身     

抗菌肽对耐甲氧西林金黄色葡萄球菌的抗菌机制研究进展

目的:了解抗菌肽对耐甲氧西林金黄色葡萄球菌(MRSA)的抗菌机制,以期为抗菌肽临床治疗MRSA肺炎提供参考。方法:查阅近年来国内外相关文献,就各种抗菌肽对MRSA的抗菌机制的相关研究进行归纳和总结。结果与结论:抗菌肽相对于抗菌药物拥有较多优势——(1)抗菌肽是生物天然免疫系统的组成部分,容易获得;抗菌肽氨基酸数较少、肽链较短,减小了合成抗菌肽的难度,为大量人工合成抗菌肽提供了可能性。(2)抗菌肽表面富含正电荷,YD1、Melittin和Bac8c均通过其表面的正电荷与MRSA表面的负电荷结合并黏附于细菌表面,进一步破坏细胞膜从而杀灭细菌;LL-37能抑制MRSA生物膜的形成并破坏已经形成的MRSA生物膜;h BD3-CBD通过在MRSA周围聚集进而发挥杀菌作用;J-AA、J-RR和J-AR利用其结构特殊性,通过内/外膜透化机制,破坏MRSA细胞膜,从而杀伤细菌。上述机制皆不涉及受体与配体之间的结合,避免了MRSA对抗菌肽产生耐药性。(3)大部分抗菌肽在极低的MIC下即已对MRSA展示出了强大的杀菌作用。抗菌肽的使用也存在一定的局限性——(1)抗菌肽的肽链较短,增加了提取难度,人工合成抗菌肽则提高了药物成本。(2)抗菌肽的短肽链和简单结构,使其稳定性较差。(3)抗菌肽是一种异种蛋白,可能诱发患者产生一系列的免疫反应和毒性作用。     

稻瘟病抗性机制研究综述

水稻对稻瘟病的抗性与温度和湿度等环境因素有关。寄主内含物对抗性产生一定的影响,稻株中硅的含量多抗性较强;感病品种一般含有较多的可溶性氮或氨基酸;抗性品种受病菌侵染后呈现迅速的褐色反应,这与酚的含量有密切关系。这种迅速的褐色反应是稻瘟病菌侵入后寄主产生的一种过敏性反应,在微细结构上表现为表皮细胞或薄壁细胞膜破碎而颗粒化以及叶绿体崩散。这些颗粒化物质可能是寄生为了阻碍入侵病菌进一步生长或使其死亡而产生的植物保护素。实际上,抗性或致病性是水稻品种与病菌生理小种间基因对基因相互作用的结果。     

Production of antitumor substances from shochu distillation remnants

This study aimed to develop a new processing method for the effective use of rice shochu distillation remnants. We examined the inhibitory effects on the growth of human lung carcinoma cells in the medium of rice shochu distillation remnants with various fungi. Interestingly, high inhibitory effects on the growth of human lung carcinoma cells in the medium of rice shochu distillation remnants with Aspergillus oryzae were obtained, although no inhibitory effect was observed in the case of synthetic medium. We therefore fractionated the medium of rice shochu distillation remnants with A. oryzae using anion-exchange and reverse-phase chromatography. Furthermore, we attempted to determine the chemical structure of compounds that showed high inhibitory effects on the growth of tumor cells. The chemical structure of 1-hydroxy-6-(1-methylpropyl)-3-(2-methylproryl)-2(1H)-pyrazinone was revealed on the basis of liquid and gas mass spectroscopies. This compound should be completely safe based on toxic test results using model mice.     

农杆菌携带柞蚕抗菌肽基因转入烟草的研究

柞蚕抗菌肽具有广谱杀菌功能,对烟草等茄科作物的青枯病假单胞菌(Pseudomonassolanacearum)具有较强的杀菌效果。人工合成抗菌肽基因(122 bp)转入根癌农杆菌(Agrobnctcrium tumefaciena),感染烟草叶盘,诱导成苗。通过对卡那霉素敏感筛选,胭脂碱脱氢酶检定及抗菌肽片段探针杂交,确认抗菌肽基因已转入烟草。现正研究其在烟草中表达及抗青枯病的可能性。     

The contractile effect of bombesin, gastrin releasing peptide and various fragments in the rat stomach strip

The contractile activity of bombesin (BB) and related peptides including the gastrin releasing peptide (GRP) was evaluated in the rat stomach strip. BB and GRP were found to elicit concentration-dependent contractile effects in concentrations varying between 5.0 X 10(-10) and 5.0 X 10(-7) M. EC50 values of BB and GRP were 6.5 X 10(-9) and 10(-8) M, respectively. The contractile effect of BB (1.5 X 10(-8) M) was not modified by a mixture of antagonists containing atropine (1.7 X 10(-6) M), mepyramine (1.2 X 10(-6) M), methysergide (1.4 X 10(-6) M), phentolamine (1.8 X 10(-6) M), propranolol (1.9 X 10(-6) M) and indomethacin (7.0 X 10(-6) M), nor by the nerve paralyzing drug tetrodotoxin (1.6 X 10(-6) M). These results suggest the existence of BB receptors in the rat stomach strip. The results also suggest that the contractile effects of BB in this tissue result from a direct effect on the smooth muscle cell. The data derived from our structure-activity study indicate that deletion of the N-terminal sequence pGlu1-Gln2-Arg3-Leu4-Gly5- from the BB molecule causes practically no loss of affinity and intrinsic activity. Further shortening of BB gives rise to a gradual reduction of both parameters. Residual contractile activity could still be observed with the tetra- and pentapeptide BB-(11-14) and BB-(10-14) at 10(-5) M.(ABSTRACT TRUNCATED AT 250 WORDS)     

Zelkovamycin, a new cyclic peptide antibiotic from Streptomyces sp. K96-0670. I. Production, isolation and biological properties

A new antibiotic termed zelkovamycin was isolated from the fermentation broth of Streptomyces sp. K96-0670 by solvent extraction, ODS column chromatography and preparative HPLC. Zelkovamycin showed antibacterial activity against Xanthomonas oryzae, Acholeplasma laidlawii, Pyricularia oryzae and Staphylococcus aureus.     

Neuropeptide Y: a powerful modulator of epithelial ion transport.

Neuropeptide Y (NPY) is a major gut peptide localized in the intestinal mucosa of several mammalian species. Ileal mucosa from rabbit and guinea-pig was mounted in Ussing chambers in order to study the effect of NPY on short circuit current. Neuropeptide Y inhibited the short circuit current when applied to the serosal side of the tissue. The maximum change in short circuit current was -50 +/- 6 microA cm-2 in the rabbit ileum and -49 +/- 14 microA cm-2 in the guinea-pig ileum. The EC50 was 3 X 10(-8) M in both species. Pretreatment of rabbit ileum with the alpha 2-adrenoceptor antagonist, yohimbine (1 X 10(-6) M) for 10 min did not reduce the response of the tissue to neuropeptide Y (1 X 10(-7) M). When applied serosally to rabbit ileal mucosa, the related peptide YY caused a maximum change in short circuit current of -60 +/- 13 microA cm-2; the EC50 was 2 X 10(-9) M. Isotopic flux studies in rabbit ileum showed that 1 X 10(-7) M neuropeptide Y enhanced mucosal-to-serosal Na+ and Cl- fluxes and reduced serosal-to-mucosal Cl- flux. Replacement of chloride with gluconate on both sides of the tissue significantly reduced the change in short circuit current produced by neuropeptide Y (1 X 10(-7) M), as did a similar replacement of bicarbonate. It is concluded that neuropeptide Y and peptide YY are the most potent neurotransmitters or hormones so far described in their ability to attenuate electrogenic transport in the small intestine.     

分泌抗水稻细菌性条斑菌单克隆抗体杂交瘤株的建立及其在种子检验上的应用

本文首次报导了通过硫酸铵沉淀法提取水稻细菌性条斑菌(Xanthomonas campestris pv.oryzicola)(以下简称细条菌)的蛋白质,并以它作抗原建立了4个杂交瘤细胞株E_5、E_8、A_5和F_(11),其培养物上清的ELISA效价为1:20～1:160,腹水效价为1:10~6～1:10~7。该4个细胞株所分泌的单克隆抗体(McAb)与58个不同来源的细条菌都呈阳性反应,而对参试的具有一定代表性的其它13个细菌种,均呈阴性反应。试验还表明,4种McAb是针对同一抗原决定簇的,其亲和力大小为:E_8>A_5>E_5>F_(11)。应用McAb进行种子带菌检验也获得成功。     

家蝇幼虫抗菌活性诱导研究

目的探讨针刺损伤方法对家蝇幼虫抗菌肽类物质诱导表达的影响,并对所得抗菌肽粗提液的保存条件进行了研究。方法人工饲养的家蝇5日龄幼虫,针刺损伤体壁后,制备抗菌肽粗提液,分别置4℃和-20℃保存30d,BCA蛋白测定试剂盒测定蛋白含量。并以大肠埃希菌为指示菌,琼脂打孔扩散法抑菌试验检测抗菌活性大小。结果针刺损伤诱导后提取的抗菌肽粗提液对大肠埃希菌的抑菌活性高于未诱导组,粗提液于4℃保存比-20℃保存更有利于抗菌肽的活性保持。结论针刺损伤法可诱导家蝇幼虫产生抗菌肽类物质,抗菌肽粗提液置于4℃保存更有利于抗菌肽活性的保持。     

25种精油对结核分支杆菌的体外药敏试验

通过体外试验,测试25种精油对结核分枝杆菌的最小抑菌浓度即MIC.选择常见的25种精油分别对结核分枝杆菌的标准菌株H37RV、临床药物敏感菌株和临床耐多药菌株,进行体外液态抑菌试验,根据药敏结果,判断精油对结核分枝杆菌的最小抑菌浓度即MIC.通过气态抑菌实验,检测精油气态抑菌MIC.液态抑菌试验结果表明,25种精油对结...     

Calcitonin gene-related peptide is localised to human airway nerves and potently constricts human airway smooth muscle.

In human airways synthetic human sequence calcitonin gene-related peptide (hCGRP), a novel peptide produced by alternative processing of mRNA from the calcitonin gene, caused concentration-dependent contraction of human bronchi (EC50 4.9 X 10(-9) M) and was significantly more potent than substance P or carbachol. The contractile response was unaffected by atropine (2 X 10(-6) M), propranolol (10(-6) M), indomethacin (10(-5) M), tetrodotoxin (3 X 10(-6) M), chlorpheniramine (10(-4) M), cimetidine (10(-5) M), or FPL55712 (10(-4) M) suggesting a direct effect of CGRP on airways smooth muscle. CGRP was detected in human airways by radioimmunoassay with highest concentrations in cartilaginous airways. CGRP was localised by immunocytochemistry to both nerves and ganglia in human airways. CGRP, is a potent constrictor of human airways and may have important effects on airway function and be implicated in the pathogenesis of bronchial hyper-responsiveness and asthma.