排序方式： 共有8条查询结果，搜索用时 15 毫秒
1
1.
为明确桃蚜内共生菌Buchnera aphidicola对桃蚜生长发育和繁殖的影响,为有效控制桃蚜提供新的思路,本试验以十字花科(萝卜)、茄科(辣椒)和葫芦科(黄瓜)蔬菜为试材,比较健康桃蚜和利福平处理后的桃蚜在3种蔬菜上的生长发育和繁殖情况。结果表明,不同浓度利福平处理后桃蚜Buchnera的DNAK基因表达量均显著降低;200μg·m L-1利福平处理后的桃蚜产蚜量、寿命和体重都显著低于健康桃蚜。说明桃蚜的内共生菌Buchnera在其生长发育过程中起着非常重要的作用,降低内共生菌的量对桃蚜可产生不利影响。 相似文献
2.
从广东省南澳县西山等养蛙场多次收集息黄杆菌病牛蛙,其症状是：歪头、狂游、双眼白内障和腹水等。从病蛙脑浆、眼底和腹水中分离到多株病原菌,急性毒性试验表明病原菌对健康牛蛙致病力强。取有代表性的981007—2等菌株进行系统的生理生化试验显示,革兰氏染色阴性、无鞭毛、无芽孢的短杆菌;分离菌株内毒素检验阳性;病原菌显示了对青霉素类药物高度耐药、好氧型、利用葡萄糖等生理、生化特性。经VITEK—AMS—60自动化检测系统鉴定为黄杆菌IIb群(Flavobacterium group IIb)。选用47种抗菌药物,通过K—B纸片扩散法对病原菌进行耐药性研究结果,分离菌株对38种抗菌药物显示耐药(占80．85％)、对4种药物中等敏感(占8．51％),仅对利福平、环丙沙星、氧氟沙星、氟啶酸、麦迪霉紊等5种药物(占10．64％)敏感。应用试管稀释法测定上述5种敏感药物的平均MIC分别是0．19、0．27、0．53、2．40和10．2ug/ml。 相似文献
3.
[目的]从植物体内分离筛选内生细菌,了解其在植物体内的定殖动态。[方法]选用5株植物内生细菌H1、DP1、CJL1、DJL12和YC1作为出发菌株,在明确其对利福平的抗性水平后,对抗性较低的H1菌株和DLJ12菌株进行紫外诱变试验。[结果]经初筛,5种植物内生菌在不含利福平的平板上生长良好,其中H1、DLJ12在浓度10μg/ml的利福平下均不能生存,其他3个菌种均能在浓度50μg/ml的利福平下生存。诱导后得到了抗利福平浓度达到80μg/ml的DLJ12菌株。[结论]该研究可为开发利用内生细菌提供理论和实践依据。 相似文献
4.
本试验旨在研究奶牛结核分枝杆菌rpoB和katG基因突变与耐药性之间的关系。将临床分离的30株牛源结核分枝杆菌,利用噬菌体生物扩增法（phage amplified biologically assay,PhaB）检测其对利福平（RFP）和异烟肼（INH）的药物敏感性,采用聚合酶链式反应—DNA直接测序法（PCR-DS）扩增rpoB和katG基因并测序,分析rpoB和katG基因突变及其耐药相关性。15株表型耐药菌株中4株单耐RFP,PCR产物直接测序后发现3株在rpoB基因531位点发生突变,突变率为75.00%（3/4）;9株单耐INH菌株中7株发生突变,6株katG基因315位点基因突变,突变率为85.71%(6/7),1株发现463位点密码子基因突变,突变率为14.29%（1/7）;2株耐RFP的同时也对INH耐药,测序发现2株均在rpoB基因的531位点〖JP2〗和katG基因的315位点发生突变。所有菌株均未发现rpoB和katG基因的缺失。rpoB基因531位点和katG基因315位点的突变是RFP和INH产生耐药性的主要机制;检测牛源结核分枝杆菌RFP耐药性的同时可以初步筛选耐多药结核分枝杆菌。 相似文献
5.
6.
Cyanide production by rhizobacteria as a possible mechanism of plant growth inhibition 总被引：8，自引：0，他引：8
Summary Volatile metabolites from a number of rhizosphere pseudomonads prevented lettuce root growth in a seedling bioassay. One of these metabolites was identified as cyanide. Direct contact between rhizobacteria and plant roots produced, with one exception, similar responses. However, not all cyanogenic isolates were plant-growth-inhibitory rhizobacteria. When grown in liquid culture, cyanogenic strains produced an average of 37 nmol HCN ml–1 over a 36-h period and inhibition of root growth occurred at concentrations as low as 20 nmol ml–1. Cyanogenic strains introduced into sand or soil also produced HCN. Two cyanogenic strains ofPseudomonas fluorescens, one (5241) a plant-growth inhibitory rhizobacterium and the other (S97) a plant-growth-promotory rhizobacterium, were used to treat bean and lettuce seedlings prior to planting in soil. Lettuce dry weight was reduced by 49.2% (day 28) and 37.4% (day 49) when inoculated with S241 whereas S97 increased growth initially (+64.5% at day 28, no difference from control at day 49). Equivalent figures for inoculated bean plants were: –52.9% and –65.1% (5241); +40.7% and +23.3% (S97). A more detailed experiment using only bean plants confirmed these contrasting affects. Inhibition by S241 was related to consistently higher levels of rhizosphere cyanide in comparison with S97-treated plants and control soils. S241 also survived in the rhizosphere at higher densities and for a longer period of time than S97. The possible contribution of rhizobacterial cyanogenesis to plant growth inhibition is discussed. 相似文献
7.
8.
A shed-microspore culture protocol was developed in Wageningen for producing doubled haploid plants in several genotypes of Indonesian hot pepper (Capsicum annuum L.). For transfer of technology to Indonesia, three factors were studied that appeared crucial for successful implementation in practice. First, application in the culture medium of a combination of the antibiotics timentin and rifampicin at the concentrations of 200 and 10 mg/l, respectively, prevented bacterial contamination from the donor explants. Second, in vitro application of colchicine (100 μM) during the first week of culture was highly effective in increasing the percentage of doubled haploid plants. Third, a comparative analysis of the ploidy level of plants regenerated from shed-microspore-derived embryos using chloroplast counts in guard cells of leaf stomata and flow cytometric measurement of leaf nuclear DNA content, revealed that the first procedure is a reliable and an easy to use method for ploidy determination with hot pepper. 相似文献
1