多菌灵对灰漠土土壤微生物的影响

[目的]选择西北干旱半干旱地区具有代表性土壤灰漠土,在室内模拟条件下,初步研究施用多菌灵对土壤微生物的影响,为多菌灵的安全使用提供科学依据.[方法]应用稀释平板计数法和氯仿熏蒸- K2SO4提取法分别测定土壤微生物种群及生物量碳、生物量氮.[结果]在整个培养期间(47 d),施用多菌灵处理土壤的生物量碳和生物量氮显著降低,且抑制作用随着多菌灵浓度的增加而增大,其EC25分别为11.39和10.44 mg/kg.多菌灵对放线菌作用不明显,但促进了细菌数量的增加;抑制了真菌的数量,且抑制作用随着多菌灵浓度的增加而增大,其EC50为7.73 mg/kg.[结论]可以用土壤生物量碳和量氮来指示多菌灵在土壤中的残留状况,用真菌数量来指示多菌灵对土壤的作用情况.     

Use of quantitative real‐time PCR to assess the in vitro survival of specific DNA gene sequences of rumen microbes under simulated abomasal conditions

The use of specific DNA sequences (DS) as a microbial marker in post‐rumen digesta requires their persistence and integrity throughout gastric digestion. The aim of this study was to evaluate in vitro the survival of microbial DS during gastric digestion and the factors involved. Gastric pH had a highly significant effect on the integrity of DS. pH 4.2 allows for a significant growth of microbes in the medium, but at pH 1.2, almost all of the DS were hydrolysed. In the presence of carboxymethylcellulose, the effect of pH was reduced, pepsin activity was inhibited and gene survival increased considerably. In the simulated abomasal conditions (pH = 2.3, 2 g/l of carboxymethylcellulose, and 40‐min retention time), almost all of the bacterial genes and around 78% of the protozoa gene sequences retained their molecular integrity throughout gastric digestion, although factors such as acidity and viscera retention time might compromise the utilisation of DS as a microbial marker.     

红树共附生微生物分离与抗白色念珠菌活性评价

对湛江市廉江高桥、东简北港2个红树林区红树的根、叶、花、果不同部位27份样品进行共附生微生物的分离及抗白色念珠菌活性的评价。采用改良M1培养基、改良马丁培养基和改良高氏一号培养基进行细菌、真菌和放线菌的分离,用美蓝酶标仪法对所筛菌株进行抗白色念珠菌活性评价。利用SPSS13.0软件对数据进行单因素方差分析和多重比较。从27份样品中共分离出384株红树林共附生微生物,其中细菌170株,真菌160株,放线菌54株,细菌和真菌为优势菌群,两者占分离总菌株数的86.0%;从384株分离菌中检测出64株具有抗白色念珠菌活性,占分离菌的16.7%;统计分析显示,除2个地区的抗白色念珠菌活性数无显著差异外,2个地区的红树共附生微生物的组成、不同类型共附生微生物的数量、不同类型共附生微生物的抗白色念珠菌活性、红树不同部位的共附生微生物数量与活性菌株数量均存在一定的差异。     

袋鼠摩根氏菌生物特性鉴定及系统发育分析

本研究利用Biolog快速鉴定系统、16S rRNA序列分析及传统细菌鉴定方法对3株分离自北京动物园袋鼠肺脏的菌株进行形态学、培养特性、生化特性、小鼠致病性等生物特性的鉴定及系统发育分析。结果表明,3株菌株均为摩根氏菌,对昆明小鼠有强致病性;3株袋鼠摩根氏菌16S rRNA序列与LMG7874模式株同源性均为99.8%,且位于系统发育树的同一分支。     

常温高效纤维素分解菌的筛选

从长期堆放稻草的土壤中分离出12株常温纤维素分解菌。采用Hutchison液体培养基,对12株纤维素分解菌进行发酵产酶试验。结果表明,通过纤维素酶活力测定,最终筛选出对纤维素分解能力较强的霉菌菌株NM5,其C1酶活力、羧甲基纤维素酶活力、滤纸酶活力分别为0.0170、0.7174、1.3435IU·mL-1。根据菌落特征和形态特征,将NM5鉴定为木霉菌属(Trichoderma)。     

复合益生菌对蛋鸡消化道微生物区系的影响

为探讨微生态制剂对蛋鸡消化道微生物区系的影响,利用致病性大肠杆菌对产蛋后期的矮小型固始鸡进行攻毒试验。结果表明,试验组蛋鸡的腹泻率明显降低,其胃、小肠、大肠、盲肠内的大肠杆菌数量也比对照组均有所降低(P>0.05),说明微生态制剂对鸡有很好的抑菌保护作用。另外,该复合益生菌可明显地提高鸡胃中乳酸菌的数量(P<0.05),而对肠道中乳酸菌的影响不明显。     

高温DXG复合菌剂对堆肥腐熟的影响

将E3、DG-3、CCS3、M8、M26菌株单独扩大培养后,按25∶15∶30∶15∶15的比例混合,配成高温DXG复合菌剂。按4‰的接种量接入新鲜配制的堆肥中进行好氧堆肥发酵。结果表明,接种复合菌剂的DXG堆肥比对照(未接种复合菌剂DXG)堆肥提前7 d达到高温期;与对照相比,全碳含量降低4.63%,腐殖酸总量提高25.2%,胡敏酸含量提高30.4%。接种复合菌剂的DXG堆肥C/N和腐殖化系数比对照堆肥提前7 d达到腐熟标准;白菜种子发芽指数表明,接种复合菌剂的DXG堆肥第12天时已初步腐熟。     

提取桑天牛成虫肠道微生物基因组DNA的2种方法比较

比较了改良CTAB法和改良SDS法两种提取桑天牛成虫肠道微生物基因组DNA的方法,结果表明：改良SDS法提取的DNA杂质较多,并且有部分降解;改良CTAB法提取的DNA纯度较高,适用于后续试验研究.     

Liquid Chromatography-Mass Spectrometry-Based Rapid Secondary-Metabolite Profiling of Marine Pseudoalteromonas sp. M2

The ocean is a rich resource of flora, fauna, and food. A wild-type bacterial strain showing confluent growth on marine agar with antibacterial activity was isolated from marine water, identified using 16S rDNA sequence analysis as Pseudoalteromonas sp., and designated as strain M2. This strain was found to produce various secondary metabolites including quinolone alkaloids. Using high-resolution mass spectrometry (MS) and nuclear magnetic resonance (NMR) analysis, we identified nine secondary metabolites of 4-hydroxy-2-alkylquinoline (pseudane-III, IV, V, VI, VII, VIII, IX, X, and XI). Additionally, this strain produced two novel, closely related compounds, 2-isopentylqunoline-4-one and 2-(2,3-dimetylbutyl)qunoline-4-(1H)-one, which have not been previously reported from marine bacteria. From the metabolites produced by Pseudoalteromonas sp. M2, 2-(2,3-dimethylbutyl)quinolin-4-one, pseudane-VI, and pseudane-VII inhibited melanin synthesis in Melan-A cells by 23.0%, 28.2%, and 42.7%, respectively, wherein pseudane-VII showed the highest inhibition at 8 µg/mL. The results of this study suggest that liquid chromatography (LC)-MS/MS-based metabolite screening effectively improves the efficiency of novel metabolite discovery. Additionally, these compounds are promising candidates for further bioactivity development.     

分子生物学技术在环境微生物检测和污染治理中的应用

综述了聚合酶链式反应技术(PCR)、生物芯片技术、酶联免疫吸附技术(ELISA)、生物传感器4种现代分子生物学技术的基本原理及其在环境微生物检测和治理中的应用,以期为现代分子生物学技术在环境微生物检测和治理中的进一步研究提供参考。