海洋Pseudomonasaeruginosasp.DES-3的鉴定以及基因ap02对其产蛋白酶的影响研究

海洋是地球上最大的生态系统,其多样独特的生态环境造就了其有别于其他环境的微生物资源。本研究利用蛋白酶的活性筛选策略,从辽宁省营口市某海洋淤泥中分离得到一株产蛋白酶的优势菌株DES-3。通过微生物形态学特征、生理生化性质和16SrDNA基因鉴定以及系统发育进化关系的分析,将该菌株鉴定为铜绿假单胞菌属,命名为Pseudomonas aeruginosa sp.DES-3。其胞外蛋白酶的最适反应温度和最适pH分别为55℃和9.0。将来自于碱性污染土壤宏基因组文库的编码碱性蛋白酶基因ap02与广宿主表达载体pBBR1MCS-5连接,转化至野生型菌株P.aeruginosasp.DES-3细胞中,成功构建了基因工程菌株P.aeruginosasp.DES-3/pBBR1MCS-5-ap02。基因工程菌株的最适反应温度为60℃,较野生型菌株提高了5℃。本研究构建基因工程菌株的策略可为菌株的改造和相应工业应用提供一定的技术参考。     

基于无人船的大洋中尺度涡观测系统展望

中尺度涡在大洋中普遍存在,研究发现其能量比大尺度海洋环流的能量大一个量级,在海洋物质能量输运和全球气候变化中起着重要的作用。受观测条件限制,目前对中尺度涡的观测主要通过卫星高度计实现,只能从海面高度来推算中尺度涡大小、分布、强度及其伴随的水体和能量输送,而卫星高度计对中尺度涡垂直结构特征认识不足,也导致了对中尺度涡所引起的上层海洋能量、热量输送估计误差偏大。目前对中尺度涡三维结构观测认识不足,展望未来将会出现基于无人船平台的大洋中尺度涡三维结构自动观测系统,该平台将集成自动水下剖面观测功能等先进技术,以便观测中尺度涡的垂直结构特征及其时空变化特征,进而可对中尺度涡带来的物质和能量输送进行系统认识。     

Seasonal variation and principle of cyanobacterial biomass and forms in the water source area of Chaohu City,China

We investigated seasonal variations in cyanobacterial biomass and the forms of its dominant population(M. aeruginosa) and their correlation with environmental factors in the water source area of Chaohu City,China from December 2011 to October 2012. The results show that species belonging to the phylum Cyanophyta occupied the maximum proportion of phytoplankton biomass,and that the dominant population in the water source area of Chaohu City was M. aeruginosa. The variation in cyanobacterial biomass from March to August 2012 was well fitted to the logistic growth model. The growth rate of cyanobacteria was the highest in June,and the biomass of cyanobacteria reached a maximum in August. From February to March 2012,the main form of M.aeruginosa was the single-cell form; M.aeruginosa colonies began to appear from April,and blooms appeared on the water surface in May. The maximum diameter of the colonies was recorded in July,and then gradually decreased from August. The diameter range of M. aeruginosa colonies was 18.37–237.77 μm,and most of the colonies were distributed in the range 20–200 μm,comprising 95.5% of the total number of samples. Temperature and photosynthetically active radiation may be the most important factors that influenced the annual variation in M. aeruginosa biomass and forms. The suitable temperature for cyanobacterial growth was in the range of 15–30°C. In natural water bodies,photosynthetically active radiation had a significant positive influence on the colonial diameter of M.aeruginosa(P0.01).     

From sequential to parallel growth of cities: Theory and evidence from Canada

This paper examines city growth patterns and the corresponding city size distribution evolution over long periods of time using a simple New Economic Geography(NEG) model and urban population data from Canada. The main findings are twofold. First, there is a transition from sequential to parallel growth of cities over long periods of time: city growth shows a sequential mode in the stage of rapid urbanization, i.e., the cities with the best development conditions will take the lead in growth, after which the cities with higher ranks will become the fastest-growing cities; in the late stage of urbanization, city growth converges according to Gibrat′s law, and exhibits a parallel growth pattern. Second, city size distribution is found to have persistent structural characteristics: the city system is self-organized into multiple discrete size groups; city growth shows club convergence characteristics, and the cities with similar development conditions eventually converge to a similar size. The results will not only enhance our understanding of urbanization process, but will also provide a timely and clear policy reference for promoting the healthy urbanization of developing countries.     

Subduction/obduction rate in the North Pacific diagnosed by an eddy-resolving model

Ventilation in the North Pacifi c is examined using data from the eddy-resolving 1/12° global HYbrid Coordinate Ocean Model(HYCOM) and Quik SCAT wind stress data. For the period January 2004 to December 2006 and area 20°–40°N, the total annual subduction rate is estimated at 79 Sv, and the obduction rate 41 Sv. Resolving the small-scale and high-frequency components of the eddy fi eld can increase the subduction rate by 42 Sv, and obduction by 31 Sv. Lateral induction is the dominant contributor to enhancement of subduction/obduction, and temporal change of mixed layer depth has a secondary role. Further analysis indicates that the high-frequency components of the eddy fi eld, especially those with timescale shorter than 10 days, are the most critical factor enhancing subduction/obduction.     

New Zircon U‐Pb Age of Granodiorite in Chifeng at the Northern Margin of North China Craton and Constraints on Plate Tectonic Evolution

正Objective The North China Craton(NCC)is one of the oldest cratons in the world.The accretionary belt at its northern margin has been the focus of scholars both at home and abroad(Zhu Junbing and Ren Jishun,2017).In recent years,a series of Late Paleozoic–Mesozoic intrusions trending E–W have been discovered within the northern margin of the NCC,forming a magmatic belt.The study     

内蒙古科尔沁右翼中旗协和尔斯德中生代火山沉积地层时代研究

内蒙古科尔沁右翼中旗协和尔斯德一带出露一套中生代地层,岩石组合主要为酸性火山碎屑岩、火山碎屑沉积岩夹碎屑沉积岩及酸性火山熔岩。1∶50000区调依据在该套地层上部层位发现的木化石组合确定其时代为中—晚侏罗世,结合岩石组合,将该套地层划分为上侏罗统满克头鄂博组。为了准确厘定该套地层时代,为木化石延限研究及区域生物地层划分对比提供依据,本次研究在低于产木化石层位的酸性火山碎屑岩中采取了锆石测年样品(LA-ICP-MS),获得锆石U-Pb年龄(165±1)Ma,时代为中侏罗世。同时采取了侵入该套地层的斑状细晶闪长岩测年样品,获得锆石年龄(131±1)Ma,限定了地层形成的上限年龄。根据岩性组合的区域对比、测年结果、木化石组合时限、地层产状特征,认为该套地层应划为中侏罗统新民组,是突泉火山-沉积盆地充填物的一部分。     

新疆乌苏市巴音沟煤层气勘探井护壁堵漏技术

在煤层气勘探井固体岩心钻探施工过程中,遇岩层构造发育、地下水系发达的施工条件,钻进中往往发生钻井多层漏失、护壁困难的情况。因煤层气勘探井对录井工作的特殊要求,护壁堵漏工作的成功与否成为钻探施工的关键。在进行钻井护壁堵漏处理时,因技术方法不得当或未采取正确的计算经常导致护壁堵漏失败,甚至引发重大的钻探事故。通过对工区施工的经验总结,提出了切实可行的护壁堵漏技术措施,为类似地层钻井勘探施工提供借鉴。