油气勘查中的微生物测量法

石油微生物测量是通过测定土壤中以渗漏轻烃为食物来源的微生物菌落来圈定烃类渗漏的范围,微生物测量受岩性和温度条件控制不明显,对其测值有重大影响的唯一因素是土壤湿度含量,微生物测量的第二个特点是其具有良好的重现性,微生物测量技术可明显区分含油区和无油区,这种方法在含油区和无油区的重现率均常在90%—100%,微生物测量法在描述地下油气储特征、预测地下构造是否含油方面,取得了良好效果,微生物测量的优势在于它耗资低廉、重视性好,是一种很有潜力的石油测量技术,值得石油勘探学者对其进行进一步的研究。

微生物方法在油气勘探中的试验研究——以松辽盆地十屋断陷为例

微生物油气勘查技术作为一种近地表勘探方法,通过检测近地表土壤中的这些噬烃菌数量变化,从而预测深部油气藏。在松辽盆地十屋断陷开展的微生物油气勘探的试验研究中,为了反映地下油气微渗漏在地表的真实体现,抑制干扰因素,获得与油气微渗漏有关的微生物异常,选择了3种微生物指标:甲烷氧化菌、纤维素分解菌、硫酸盐还原菌。检测油气藏上方近地表土壤中3种菌落的数目,然后根据它们之间的关系,找出微生物异常点,结合其它地球化学指标对微生物异常进行了分析,并推测地下油气的分布规律,同时探讨了微生物、地球化学异常与石油地质的关系,油气预测效果较显著。

Variations of phyllosphere microorganisms in asymptomatic and tobacco brown spot leaves before and after spraying 12% difenoconazole + fluxapyroxad SC

12%difenoconazole+fluxapyroxad SC(commercial name:Jiangong)was first released by BASF in China in 2016.It has been registered to control many diseases,including pear scab,apple Alternaria leaf spot,tomato early blight,cucumber powdery mildew,etc.This study evaluated the bioactivity of Jiangong against Alternaria alternata and explored variations of phyllosphere microorganisms in both asymptomatic and tobacco brown spot leaves at different persistence periods(0,5,10,and 15 days post-fungicide application)using high-throughput sequencing technology.The results indicated that Jiangong effectively inhibited mycelial growth(average EC_(50) value of 0.51μg/mL),conidia germination(average EC_(50) value of 3.47μg/mL),and the carbon metabolism of A.alternata.Both asymptomatic and symptomatic leaves presented complex microbial communities.Higher fungal diversity was noted in asymptomatic leaves,while higher bacterial diversity was found in symptomatic leaves.After application,the diversity and abundance of microbial community structures in both types of leaves changed over time.Fungal microbiome communities showed greater sensitivity than bacterial groups,with the microbiome communities of asymptomatic leaves being more affected than those of symptomatic leaves.Fungal community diversity decreased for both symptomatic and asymptomatic leaves after 5 days of application,while the diversity of fungal community in symptomatic leaves showed an upward trend after 10 days of application.Meanwhile,bacterial community diversity increased in both symptomatic and asymptomatic leaves after 5 days of application but then declined in asymptomatic leaves after 15 days.The abundance of the dominant function group of phyllosphere bacteria(metabolism,genetic information processing,environmental information processing)was not affected by the application of Jiangong.However,the abundance of the dominant function group of phyllosphere fungi(animal pathogen-endophyte-wood saprotroph,endophyte-plant pathogen,plant pathogen-undefined saprotroph)was significantly affected by the application of Jiangong,and high variation was found in symptomatic leaves than that of asymptomatic leaves.The application of Jiangong-induced alterations in the community structure of the tobacco phyllosphere microbiome provides a basis for future tobacco brown spot control strategies based on phyllospheric microecology.

激光吸收光谱技术在大肠杆菌生长测量中的应用

将高灵敏的激光吸收光谱技术应用于微生物生长测量领域,实现了对以大肠杆菌为例的微生物生长过程实时监测和生长曲线的绘制。设计并搭建了一套实验测量装置,对大肠杆菌生长过程中新陈代谢产生的CO_(2)的二次谐波信号进行实时监测并拟合,测量获取了大肠杆菌在25、26、29、32、34、37、43℃培养条件下的生长曲线。实验结果表明测得的生长曲线能够准确反映大肠杆菌在不同温度下生长调整期、对数期、稳定期及衰亡期的时间,证明了基于激光吸收光谱技术的微生物生长代谢产物CO_(2)法可以很好地应用于微生物生长测量领域。

Investigations into the corrosive environments contributing to premature failure of Australian coal mine rock bolts

University of New South Wales(UNSW Australia) had been involved in the study of premature failure of rock bolts in Australia coal mines from the initial identification of the problem in 1999. Rock bolt steel changes over the last decade appear to have not reduced the incidence of failures. A broadened UNSW research project funded by the Australian Research Council(ARC) and Industry has targeted finding the environmental causes through extensive field and laboratory experiments. This paper describes the field studies conducted in underground coal mines,in particular attempts to measure the contribution to corrosion from groundwater,mineralogy and microbial activity. Various underground survey techniques were used to determine the extent of broken bolts,with the presence of both stress corrosion cracking(SCC) and localized deep pitting making no single technique suitable on their own.Groundwater found dripping from bolts across various coalfields in Australia were found to be not aggressive and known groundwater corrosivity classification systems did not correlate to where broken bolts were found. In-hole coupon bolts placed in roof strata containing claystone bands confirmed the clay as being a major contributor to corrosion. Microbes capable of contributing to steel corrosion were found to be present in groundwater,and culturing of the microbes taken from in-situ coupon bolts proved that the bacteria was present on the bolt surface. An ‘in-hole bolt corrosion coupon' development by the project may have multiple benefits of (1) helping quantify newly developed corrosivity classification systems,(2) providing an in-situ ground support corrosion monitoring tool,and (3) for testing possible corrosion protection solutions.

Changes of microbial diversity during pyrite bioleaching

Microorganisms,one of the key factors affecting the bioleaching process,change the components of extracellular polymeric substance(EPS)and community structure to survive in leaching environments.In this work,Fourier transform infrared(FTIR),X-ray powder diffraction(XRD)and 16S rDNA high-throughput sequence analyses were used to reveal the microbial changes in planktonic and sessile phases during bioleaching.The results showed the occupation of sessile cells decreased from 66.2%to(10±3)%.After bioleaching,the planktonic and sessile cells have similar EPS,but they are different from the original cells.Pyrite dissolution mainly occurs at the early and late stages with the decreasing of particle diameter,by 50%and 40%,respectively.The 16S rDNA gene based sequence analysis results in total of 1117420 Reads across the six samples,presented among 7 phyla,9 classes,17 orders,23 families and 31 genera.Genera Leptospirillum and Sulfobacillus are the main bacteria at the early and middle stages,and Leptospirillum is the main genus at the end of bioleaching.Aquabacterium and Acidovorax are special genera in sessile cells and Weissella is special in planktonic ones.

Insights into the microbial diversity and community dynamics of Chinese traditional fermented foods from using high-throughput sequencing approaches

Chinese traditional fermented foods have a very long history dating back thousands of years and have become an indispensable part of Chinese dietary culture. A plethora of research has been conducted to unravel the composition and dynamics of microbial consortia associated with Chinese traditional fermented foods using culture- dependent as well as culture-independent methods, like different high-throughput sequencing （HTS） techniques. These HTS techniques enable us to understand the relationship between a food product and its microbes to a greater extent than ever before. Considering the importance of Chinese traditional fermented products, the objective of this paper is to review the diversity and dynamics of microbiota in Chinese traditional fermented foods revealed by HTS approaches.