一株高效抑藻放线菌的分离筛选及鉴定

从福建云霄国家红树林自然保护区滩涂沉积物样品中,共分离获得521株纯培养物.通过检测球形棕囊藻(Pha-eocystis globosa)荧光强度计算抑藻率,从521株菌中筛选到27株具有抑藻活性的菌株.在27株抑藻菌中,菌株O3-26对球形棕囊藻具有最高的抑藻率(高达96.71%).菌株O3-26的抑藻谱实验显示,该菌株抑藻活性表现出一定的种属特异性,对硅藻门(Bacillariophyta)的三角褐指藻(Phaeodactylum tricornutum)和中肋骨条藻(Skeletonema costatum)2株测试藻株没有抑制作用,而对绿藻门(Chlorophyta)盐生杜氏藻(Dunaliella salina)和自养小球藻(Chlorella autotrophi-ca)2株藻株具有较强抑藻作用.扫描电镜观察显示,该菌株孢子丝直至螺旋状且孢子表面带刺.生理生化实验显示,该菌株在所得到的大多数培养基上生长良好,在营养琼脂培养基中可以产生水溶性色素;不能在棉子糖作为唯一碳源的培养基上生长.16SrRNA基因相似性分析表明,菌株O3-26属于链霉菌属(Streptomyces),并与灭癌素链霉菌(Streptomycesgancidicus)15412菌株具有最高的同源性(99%).生理生化实验表明,二者之间生理特征存在一定差异.综合形态特征、生理特征以及系统发育分析的结果,鉴定该菌株为灭癌素链霉菌

Metagenomic insights into soil microbial communities under biofuel crops

为应对化石燃料短缺危机和大量使用而导致的环境污染，全球都在积极促进清洁的可再生生物燃料的开发。目前已实现产业化的生物燃料包括生物乙醇、生物柴油等，主要以粮食作物玉米、大豆、甘蔗等为原材料，因此产生了“与人争粮、与粮争地”的矛盾。为此，各国将注意力转移到基于非粮食作物的生物燃料生产。其中，种植柳枝稷、芒草、杨树等低投入且生长快速的多年生植物用于生产纤维素乙醇以替代部分石油作为运输燃料，更是受到广泛关注。深入研究种植这些作物对土壤微生物的影响已成为纤维素乙醇可持续性研究的重要组成部分，同时，通过对土壤微生物与作物关系的研究反过来也可以更好的指导这些生物燃料作物的种植。 本论文以美国能源部“五大湖...To address the critical shortages of fossil fuels and environmental issues caused by their excessive usage, countries around the world are actively promoting the development of clean and renewable biofuels. The current industrialized biofuels including bioethanol and biodiesel are mainly based on corn, soybean, sugarcane, etc., and thus compete for food crops and land. To avoid this competition, i...学位：理学博士院系专业：生命科学学院_水生生物学学号：2162011015397

Isolation and Identification of a High Algicidal Actinomycete

通讯作者：[email protected][中文文摘]从福建云霄国家红树林自然保护区滩涂沉积物样品中，共分离获得521株纯培养物．通过检测球形棕囊藻(Phaeocystisglobosa)荧光强度计算抑藻率，从521株菌中筛选到27株具有抑藻活性的菌株．在27株抑藻菌中，菌株03-26对球形棕囊藻具有最高的抑藻率(高达96.71%).菌株03-26的抑藻谱实验显示，该菌株抑藻活性表现出一定的种属特异性，对硅藻门(Bacillariophyta)的三角褐指藻(Phaeodactylum tricornutum)和中肋骨条藻(Skeletonema costatum)2株测试藻株没有抑制作用，而对绿藻门(Chlorophyta）盐生杜氏藻(Dunaliella salina)和自养小球藻(Chlorella autotrophica)2株藻株具有较强抑藻作用．扫描电镜观察显示，该菌株孢子丝直至螺旋状且孢子表面带刺．生理生化实验显示，该菌株在所得到的大多数培养基上生长良好，在营养琼脂培养基中可以产生水溶性色素；不能在棉子糖作为唯一碳源的培养基上生长．１６ＳｒＲＮＡ基因相似性分析表明，菌株Ｏ３－２６属于链霉菌属（Ｓｔｒｅｐｔｏｍｙｃｅｓ），并与灭癌素链霉菌（Ｓｔｒｅｐｔｏｍｙｃｅｓｇａｎｃｉｄｉｃｕｓ）１５４１２菌株具有最高的同源性（９９％）．生理生化实验表明，二者之间生理特征存在一定差异．综合形态特征、生理特征以及系统发育分析的结果，鉴定该菌株为灭癌素链霉菌．[英文文摘]521 strains were isolated from mangrove sediments in the Yunxiao Mangrove National Nature Reserve,Fujian,China.27 algicidal isolates were screened based on the analysis of fluorescence intensity of Phaeocystis globosa.The strain named O3-26,which showed the highest algcidal activity(96.71%) against P.globosa among these 27 algicidal isolates,was studied in this article.The test of algicidal spectrum illustrated O3-26 showing a algicidal characteristic of algae species specificity,with high algicidal effects on Dunaliella salina and Chlorella autotrophica,no algicidal effects on phaeodactylum tricornutum and Skeletonema costatum.Observed by scanning electron microscope,03-26 has spiral sporot hrix and barbed spores.This strain can grow well in most of the medium in this article,and produce soluble pigment in nutrient agar.The physiological tests demonstrated that 03-26 owns a wide range of carbon sources,but can be grown on raffinose medium as sole carbon source.On the basis of 16 SrRNA gene sequence similarity,the strain,03-26 was shown to be related most closely to Streptomyces gancidicus 154152(99%).Although some differences fromS.gancidicus were tested from physiological and biochemical experiments,03-26 was still indentificated as S.gancidicus by comparison on morphological,physiogical characteristics and phylogenetic analysis.国家高技术研究发展计划(863)项目(2008AA09Z408); 国家自然科学基金项目(40930847,31070442);近海海洋环境科学国家重点实验室(厦门大学)访问学者基金项目(MELRS1124

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies