Transforming the plastome: genetic markers and DNA delivery systems     

P. J. Dix  T. A. Kavanagh 《Euphytica》1955,85(1-3):29-34

Summary Stable chloroplast transformants were first obtained following particle bombardment of tobacco leaves, and later by PEG-mediated uptake of DNA by protoplasts. The transforming DNA in these studies was itself of plastid origin and carried double (streptomycin, spectinomycin) antibiotic resistance which was used to select transformants. Integration was by homologous recombination, and both donor and recipient were Nicotiana species. Recent characterisation of plastid mutants of Solanum nigrum has allowed the extension of this gene replacement approach to include Nicotiana:Solanum combinations.The introduction of functional heterologous genes into the plastome is an alternative approach based on the use of constructs in which a bacterial resistance gene is flanked by sequences homologous to a region of the recipient plastome. Thus homologous recombination in the flanking sequences allows introduction of a foreign gene. A large number of putative transformants can be generated by the method, but this apparent attraction is partly offset by the need for repeated cycles of re-selection to obtain homoplasmic plants. In contrast, homoplasmy can be accomplished in a single selection step using plastome-encoded antibiotic resistance markers.The plastome is an attractive target for the introduction of useful genes into crop plants, as maternal inheritance acts as an insurance against unwanted spread of the foreign gene, and the large plastome copy number ensures immediate gene amplification and may influence levels of expression. Specific characters encoded on the plastid DNA, including components of photosynthesis and other aspects of metabolism, will also become open to manipulation as a consequence of developments in plastid transformation.  相似文献   

樱桃园土壤优势放线菌的分离及其促长功能研究   总被引：1，自引：1，他引：0  

刘灵芝  秦嗣军  吕德国  王冰营 《中国农业科学》2013,46(6):1221-1229

【目的】分离、筛选樱桃园土壤优势放线菌菌株,研究其在生物防治与植物促长中的应用潜力。【方法】采用皿内拮抗与发酵液促生试验分析优势放线菌菌株抗生与促进生长功能。对具有良好抑菌与促进生长作用的菌株F4-5,通过16S rDNA 序列分析研究其分类地位。【结果】从樱桃[（Cerasus avium Moench (L.) / C. sachalinensis (L.) Kom.）园土壤中共分离获得32株优势放线菌菌株。与5月和11月相比,8月土壤中放线菌数量最多。各时期分离优势放线菌的抑菌作用与促进生长能力随生育期而各异,总体上,2010年8月分离菌株抑菌与促进生长效果较为明显。放线菌菌株F4-5对金黄色葡萄球菌(Staphylococcus aureus ) 、大肠杆菌(Escherichia coli ) 、枯草芽孢杆菌(Bacillus subtilis )和蜡质芽孢杆菌(Bacillus cereus) 4株供试细菌,以及木霉（Trichoderma viride）、根霉（Rhizopus stolonifer）和黑曲霉（Aspergillus niger）3株供试真菌均表现出明显抑制效果,具有广谱抗生性。同时,菌株F4-5亦可显著促进山荆子（Malus baccata (L.) Brokh.）种子萌发与胚根生长,较对照分别提高了201.1%和43.5%,表现出抗生与促进生长双重效应。根据形态、培养特征及16S rDNA 序列分析, 初步鉴定菌株F4-5为灰黄链霉菌（Streptomyces flavogriseus）。【结论】不同时期樱桃园土壤放线菌数量、分布、抗生及促进种子萌发特性变化较大,灰黄链霉菌F4-5菌株具有良好的广谱抗生性与促进种子萌发、胚根生长的作用。  相似文献   

乳房淋巴结内注射胸腺五肽治疗奶牛隐性乳房炎的研究     

潘韬  张丽佳  樊青  裴增杨  胡松华 《兽医大学学报》2013,(9):1431-1435

将患隐性乳房炎的奶牛30头随机分为5组,3个试验组奶牛分别在乳房淋巴结内注入低、中、高剂量的胸腺五肽（TP-5）;阳性药物对照组奶牛在乳房内灌注＂乳炎＂（主要含林可霉素和新霉素）;空白对照组,不作任何处理。治疗前和治疗后1、2、3周采集奶样进行细菌学检查和体细胞计数（SCC）。停药后4d之内每天采样进行牛奶抗生素残留检测。结果表明,和空白对照组比较,经药物治疗后各组感染乳区有不同程度减少,牛奶SCC减少的幅度依次为阳性药物对照组〉TP-5高剂量组〉TP-5中剂量组〉TP-5低剂量组。＂乳炎＂治疗组在停药后3d之内可以在牛奶中检测到抗生素残留,而TP-5则没有。因此,TP-5对奶牛隐性乳房炎具有治疗作用,并且不会在牛奶中造成有害的残留。  相似文献   

贝莱斯芽胞杆菌次生抗生物质的研究进展          下载免费PDF全文

杨冰  杜春梅 《中国生物防治学报》2022,38(2):502-512

贝莱斯芽胞杆菌广泛分布于自然界,其次生抗生物质丰富,具有开发新型生物防治剂制剂的潜力。其基因组含有多种抗生物质的生物合成基因簇,如表面活性素、丰原素、杆菌霉素D等脂肽类化合物,杆菌烯、大环内酰亚胺、艰难菌素等聚酮类化合物,以及杆菌素和杆菌溶素等。除杆菌素以外,贝莱斯芽胞杆菌的绝大部分次生抗生物质依赖4'-磷酸泛酰转移酶（Sfp）途径合成。本文归纳和总结了贝莱斯芽胞杆菌抗生物质的化学结构、生物合成基因簇及其调控机制以及他们在控制植物、动物和人类疾病上的应用,以期为今后利用贝莱斯芽胞杆菌及其代谢产物研发生防制剂或临床药物提供科学依据。  相似文献   

Two New Antibiotic Pyridones Produced by a Marine Fungus,Trichoderma sp. Strain MF106     

Bin Wu  Vanessa Oesker  Jutta Wiese  Rolf Schmaljohann  Johannes F. Imhoff 《Marine drugs》2014,12(3):1208-1219

Two unusual pyridones, trichodin A (1) and trichodin B (2), together with the known compound, pyridoxatin (3), were extracted from mycelia and culture broth of the marine fungus, Trichoderma sp. strain MF106 isolated from the Greenland Seas. The structures of the new compounds were characterized as an intramolecular cyclization of a pyridine basic backbone with a phenyl group. The structure and relative configuration of the new compounds were established by spectroscopic means. The new compound 1 and the known compound 3 showed antibiotic activities against the clinically relevant microorganism, Staphylococcus epidermidis, with IC₅₀ values of 24 μM and 4 μM, respectively.  相似文献   

常用抗菌药物和消毒剂对刺参幼体的急性毒性试验   总被引：8，自引：1，他引：8  

李强  罗永成  李华  常亚青 《大连水产学院学报》2005,20(2):105-110

常用抗菌药物和消毒剂对刺参幼体的急性毒性试验结果表明:抗菌药物对幼参的毒性依次为土霉素>氟哌酸>新诺明,土霉素对刺参幼体24、48h的LC50分别为166、115mg/L,氟哌酸24、48h的LC50分别为457、407mg/L,新诺明48、72h的LC50为300、224mg/L;常用消毒剂对幼参的毒性依次为二氧化氯>高锰酸钾>福尔马林>次氯酸钠>敌百虫,二氧化氯有效氯对刺参幼体24h的LC50为0.36mg/L,高锰酸钾24、48、72h的LC50分别为3.02、2.09、1.26mg/L,福尔马林24、48、72h的LC50(体积分数)分别为8.71×10-6、4.37×10-6、1.62×10-6,次氯酸钠有效氯24、48、72h和96h的LC50(体积分数)分别为44.7×10-6、14.5×10-6、10.0×10-6和9.3×10-6,敌百虫24、48、72h和96hLC50分别为479、158、105mg/L和78mg/L。另外,作者还描述了刺参幼体对常用消毒剂和抗菌药物的反应,推算了其安全浓度,探讨了常用消毒剂和抗菌药物在刺参养殖中使用的可行性。  相似文献   

拮抗真菌F-310对辣椒疫霉菌的抗生活性及防效   总被引：3，自引：3，他引：3  

马艳  常志州  朱万宝  黄红英  叶小梅 《江苏农业学报》2004,20(3):180-183

筛选得到的1株对辣椒疫霉菌具有拮抗作用的真菌F 310在平板上能强烈地抑制辣椒疫霉菌丝的生长。F 310培养滤液能抑制辣椒疫霉菌孢子囊的形成及孢子囊、孢子的萌发,同时能杀死菌丝细胞使其丧失致病性。F 310培养滤液粗提物同样具有抗生活性。盆栽试验结果显示,土壤接种F 310菌株及培养滤液对辣椒疫病的防治效果可达到64 5%。  相似文献   

肉鸭传染性浆膜炎的诊断和防制     

徐耀辉  蒋增海  王岩  卢建洲 《郑州牧业工程高等专科学校学报》2007,27(2):6-7,33

郑州市郊某鸭场发生一起临床症状、剖检病变疑似鸭传染性浆膜炎鸭疫里氏杆菌病例,从中分离到1株细菌。对分离的病菌进行分离培养、生化试验和动物试验,鉴定为鸭疫里默氏杆菌。药敏实验表明鸭疫里氏杆菌对头孢噻肟、卡那霉素、环丙沙星等敏感性较高。通过治疗,病情得到了控制。  相似文献   

木醋液的提取及其抑菌效果   总被引：8，自引：0，他引：8  

鲁京兰  申凤善  李太元  太俊哲 《延边大学农学学报》2002,24(1):30-33

利用柞木边脚料和烧条提取了木醋液，并用其进行抑菌试验的结果表明：木醋液具有较强的抑菌效果，尤其是柞木干馏液对病蛙分离菌的抑菌效果更加显著。  相似文献   

Bactericidal kinetics of marine-derived napyradiomycins against contemporary methicillin-resistant Staphylococcus aureus     

Haste NM  Farnaes L  Perera VR  Fenical W  Nizet V  Hensler ME 《Marine drugs》2011,9(4):680-689

There is an urgent need for new antibiotics to treat hospital- and community-associated methicillin-resistant Staphylococcus aureus (MRSA) infections. Previous work has indicated that both terrestrial and marine-derived members of the napyradiomycin class possess potential anti-staphylococcal activities. These compounds are unique meroterpenoids with unusual levels of halogenation. In this paper we report the evaluation of two previously described napyradiomycin derivatives, A80915A (1) and A80915B (2) produced by the marine-derived actinomycete, Streptomyces sp. strain CNQ-525, for their specific activities against contemporary and clinically relevant MRSA. Reported are studies of the in vitro kinetics of these chemical scaffolds in time-kill MRSA assays. Both napyradiomycin derivatives demonstrate potent and rapid bactericidal activity against contemporary MRSA strains. These data may help guide future development and design of analogs of the napyradiomycins that could potentially serve as useful anti-MRSA therapeutics.  相似文献