润滑油降解菌的筛选及其alkB基因的PCR分析

从重庆地区受润滑油污染的酸性土壤中筛选润滑油降解菌,采用形态学和16srDNA分析鉴定其分类地位,研究它们以润滑油作为唯一碳源的生长能力,并对其烷烃羟化酶基因(alkB)进行了PCR分析.从污染的土壤样品中分离出11株细菌.用酶法检测和干重法检测发现9株细菌均能分解利用润滑油,16srDNA分析表明这些菌分属Pseudomonas,Cupriavidus,Bacillus,Acinetobacter,Stenotrophomonas.对这些菌株的PCR分析发现其alkB基因扩增片段大小介干160和400 bp之间.     

妊娠北极狐流产菌的分离与鉴定

从妊娠 35～ 50天的北极狐流产胎儿脏器中分离到一种革兰氏阴性杆菌 ,经培养特征、形态、生理生化、致病力测定 ,证实为鸡伤寒沙门氏菌 ,确定该菌为引起狐流产的病原菌     

Der pH-Wert und das Vorkommen niedermolekularer Fettsäuren im Naßkern der Buche (Fagus sylvatica L.)

The pH-value and the occurrence of fatty acids in wetwood of European Beech (Fagus sylvatica L.). At the border of the wetwood area pH-value of the capillary liquid was altered from acid to neutral conditions. Fatty acids frequently occurred in wetwood. Probes with pH-values higher than 6.8 often were deeply black stained.     

消毒方法对红花种子发芽率的影响和种子环境细菌研究

红花（Carthamus tinotorius L.）种子在发芽和组培中染菌情况严重,发芽率较低,针对这一现象,对供试红花种子进行消毒以降低染菌率并提高发芽率。选择种子预浸泡时间、消毒剂种类、消毒时间3个因素,采用L₉（3 ⁴）正交试验,以种子的发芽率、发芽势和染菌率为考察指标,综合分析种子消毒效果。结果表明,消毒剂种类是影响红花种子消毒效果的最重要因素。红花种子最佳消毒方法为种子消毒前用无菌水预浸泡12h,再经2% NaClO消毒10min,染菌率仅为8%,发芽率高达90.67%。另外,对分离纯化消毒后种子所带的细菌16S rDNA（GenBank登录号：MH190221）进行了PCR扩增,序列Blast结果显示,该菌为阿耶波多芽孢杆菌（Bacillus aryabhatti）,初步判断该菌可能为红花种子内生菌。该研究结果为快速获得生长良好的无菌苗、后续的组织培养以及遗传转化奠定了基础。     

引起黑木耳栽培种污染细菌的分离与鉴定

以污染的木耳三级栽培种"荤油"层为材料,采用多种分离纯化方法、16S rDNA分子鉴定法以及回接试验,分离并鉴定出引起食用菌栽培种污染的细菌3株,其分属于Paenibacillus、Bacillus和Lysinibacillus属,分别命名为YC3、YC8、YC12。     

Effect of antimicrobial compounds on cut Gerbera flowers: Poor relation between stem bending and numbers of bacteria in the vase water

Gerbera flowers (Gerbera jamesonii) often show stem bending. In four cultivars (Tamara, Liesbeth, Cora, and Mickey), we tested the effects on bending of antimicrobial compounds (chlorine bleach, a slow release chlorine compound, 8-hydroxyquinoline citrate [HQC], silver nitrate, carvacrol and thymol), some combined with sugars. At concentrations used for other cut flowers, inclusion in the vase solution of several of the antimicrobial compounds delayed bending, had no effect, or hastened bending. Hastening of bending was found at higher concentrations. It was accompanied with visible damage on the stem ends. Results with HQC indicated high toxicity as it did not delay bending at any of the concentration tested (100–400 mg L⁻¹). At 200 mg L⁻¹ HQC induced growth of bacteria that were not found in the controls. The number of bacteria in the vase water showed a low correlation with bending. Visible toxicity on the stem surface was often associated with a high bacteria count. However, at relatively high concentrations of the antimicrobial compounds stem bending was associated with a low count. This indicated an effect other than bacteria. Water uptake was low in stems that bent early. It is hypothesized that material from dead stem cells resulted in a xylem blockage which led to early bending. Sucrose at 15 g L⁻¹ in combination with an antimicrobial compound (slow release chlorine, HQC) resulted in the absence of stem damage and produced much less bending than the same concentration of the antimicrobial compounds alone. Sucrose apparently counteracted the toxic effects of the antimicrobial chemicals.