Insights into functional genes and taxonomical/phylogenetic diversity of microbial communities in biological heap leaching system and their correlation with functions

Applied Microbiology and Biotechnology - Although the taxonomical/phylogenetic diversity of microbial communities in biological heap leaching systems has been investigated, the diversity of...     

Characteristics and metabolic pathway of Alcaligenes sp. TB for simultaneous heterotrophic nitrification-aerobic denitrification

Applied Microbiology and Biotechnology - A novel heterotrophic nitrification-aerobic denitrification bacterium, Alcaligenes sp. TB (GenBank accession no. JQ044686), was isolated from a rotating...     

Enrichment and characteristics of mixed methane-oxidizing bacteria from a Chinese coal mine

In methane-rich environments, methane-oxidizing bacteria usually occur predominantly among consortia including other types of microorganisms. In this study, artificial coal bed gas and methane gas were used to enrich mixed methanotrophic cultures from the soil of a coal mine in China, respectively. The changes in microbial community structure and function during the enrichment were examined. The microbial diversity was reduced as the enrichment proceeded, while the capacity for methane oxidation was significantly enhanced by the increased abundance of methanotrophs. The proportion of type II methanotrophs increased greatly from 7.84 % in the sampled soil to about 50 % in the enrichment cultures, due to the increase of methane concentration. After the microbial community of the cultures got stable, Methylomonas and Methylocystis became the dominant type I and type II methanotrophs, while Methylophilus was the prevailing methylotroph. The sequences affiliated with pigment-producing strains, Methylomonas rubra, Hydrogenophaga sp. AH-24, and Flavobacterium cucumis, could explain the orange appearance of the cultures. Comparing the two cultures, the multi-carbon sources in the artificial coal bed gas caused more variety of non-methanotrophic bacteria, but did not help to maintain the diversity or to increase the quantity and activity of methanotrophs. The results could help to understand the succession and interaction of microbial community in a methane-driven ecosystem.     

检测小鼠肝炎病毒的SNaPshot分型技术及其应用

建立一种能对MHV_1、MHV_3、JHM、A_(59) 4种常见小鼠肝炎病毒(Murine Hepatitis Virus,MHV)进行分型检测的SNaPshot新方法。根据MHV 4种常见毒株基因序列比对结果,设计内外两对PCR通用引物和4个单碱基延伸引物,提取MHV 4种常见毒株RNA,逆转录后进行PCR扩增,纯化扩增产物,用SNaPshot方法进行单碱基延伸,将产物进行毛细管凝胶电泳,根据电泳结果分析毒株基因型。优化SNaPshot分析条件,进行灵敏度、特异性分析。用ELISA法和SNaPshot方法检测41例小鼠(Mus musculus)血清样本,将阳性样本进行克隆测序检测。当T1~T4引物修饰的poly T的数量分别为0、3、10和15,其浓度比为4︰6︰5︰10,引物大小分别为16 bp、19 bp、26 bp和31 bp时,SNa Phot分型检测MHV c DNA的最低浓度为1.25 mg/L,特异性为100%,与ELISA和T-克隆测序比较,其准确性为100%(41/41),阳性样本均为JHM毒株。实验结果说明,所建立的SNaPshot检测方法能对MHV_1、MHV_3、JHM、A_(59)进行分型检测,并且具有灵敏、特异、准确的优点。     

不同发育期贝居腹盾吸虫体内乙酰胆碱酯酶分布特征

乙酰胆碱酯酶(ACh E)被证明存在于多种吸虫体内,但是关于ACh E在吸虫发育过程中的分布变化情况却少有报道。本实验以贝居腹盾吸虫(Aspidogaster conchicola)为研究对象,选取不同发育阶段的虫体,分别采用醋酸洋红染色和乙酰胆碱酯酶组织化学染色方法,对比处于不同发育阶段虫体的正常结构及乙酰胆碱酯酶分布特征,了解乙酰胆碱酯酶在吸虫发育过程中的分布变化规律。结果显示,从河蚌(Anodonta woodiana)体内获得的虫体根据内部器官的发育程度,可以分为4个不同发育阶段,即幼虫阶段Ⅰ、幼虫阶段Ⅱ、成虫阶段Ⅰ、成虫阶段Ⅱ。乙酰胆碱酯酶的分布在不同发育阶段存在着明显差异,幼虫阶段Ⅰ的睾丸及阴茎囊基部最先出现乙酰胆碱酯酶阳性反应,幼虫阶段Ⅱ在子宫末段膨大部位出现阳性反应;成虫阶段Ⅰ的卵黄腺、输卵管出现阳性反应,并且随着虫体的发育上述部位的阳性反应逐渐加强。而该吸虫的附着、消化、排泄器官在发育早期即出现较强的阳性反应,并伴随虫体发育全过程。该吸虫的神经系统在幼虫早期既已具备脑神经节、主要神经干等结构,而完整、复杂的中枢神经结构至成虫阶段才得以清晰显现。结果表明,乙酰胆碱酯酶的分布区域及反应程度随着虫体的发育而出现变化。     

河北张家口康巴诺尔湖国家湿地公园遗鸥繁殖群新发现

2014年4月14日在张家口市康保县康巴诺尔湖国家湿地公园(东经114°35′06″~114°36′32″,北纬41°49′05″~41°50′33″)发现遗鸥(Larus relictus)3 000余只。同年7月在湖边发现新繁殖的遗鸥幼鸟觅食。2015年4月底发现遗鸥在湖心岛筑巢产卵,同年6月采用国产大疆精灵3四轴航拍飞行器航拍法及样方法统计湖心岛遗鸥种群数量,共记录遗鸥成鸟2 100余只,806巢,出壳雏鸟2 080只。此次发现属于我国遗鸥繁殖地的新发现。     

Genome shuffling筛选ε-聚赖氨酸高产菌及其对代谢流量分配的影响

【目的】从代谢流量分配的角度,探讨Genome shuffling导致链霉菌ε-聚赖氨酸合成量提升的原因。【方法】从葡萄糖耐受型的亲本菌株Streptomyces sp.AS32和ε-聚赖氨酸耐受型的亲本菌株Streptomyces albulus F15出发,进行三轮Genome shuffling,筛选得到ε-聚赖氨酸产量提高的链霉菌株Streptomyces sp.AF3-44,采用通量分析方法构建链霉菌ε-聚赖氨酸合成代谢网络,并对上述3株菌的代谢通量进行比较。【结果】AF3-44的ε-聚赖氨酸摇瓶产量为3.1 g/L,较AS32和F15分别提高了34%和29%。3株菌株中AS32三羧酸循环(TCA)的代谢通量最高;F15磷酸戊糖途径(PPP)代谢通量最高;AF3-44流向赖氨酸合成前体天冬氨酸以及ε-聚赖氨酸的通量最高,TCA和PPP通量位于两亲本菌株的中间水平,其中TCA中流向异柠檬酸的通量分别为AS32和F15的77%和116%,PPP中流向5-磷酸核酮糖的通量分别为AS32和F15的149%和92%。【结论】Genome shuffling导致了代谢流的重新分布,流向前体赖氨酸和ε-聚赖氨酸通量的增加,以及PPP和TCA通量配比的改变是链霉菌ε-聚赖氨酸合成量增加的重要因素。