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Limited distribution and mechanism of the TetX4 tetracycline resistance enzyme

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Science Bulletin 2019年第20期64卷 1478-1481页

作者： yongchang xu Lizhang Liu Jian Sun Youjun Feng Department of Pathogen Biology&Microbiology and Department of General Intensive Care Unit of the Second Affiliated Hospital Zhejiang University School of MedicineHangzhou 310058China National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria South China Agricultural UniversityGuangzhou 510642China

Tetracyclines,a group of antimicrobial agents targeting protein synthesis,have been extensively used in agricultural,veterinary,and clinic settings[1].The sporadic rise in tetracycline resistance is partially due to the occurrence of efflux pumps and/or ribosome protection[1,2].The growing body of tetracycline-inactivating enzymes(e.g.,TetX(X1 to X4)[3,4]and Tet(47 to 55)[5])represents an alternative mechanism for tetracycline resistance,and threatens the renewed interest of tigecycline as a last-resort defense against lethal infections with carbapenem-resistant Enterobacteriaceae and Acinetobacter species.

关键词： Limited distribution and mechanism of the TetX4 tetracycline resistance enzyme

Low-mature gases and their resource potentiality

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Chinese Journal Of Geochemistry 2009年第3期28卷 231-238页

作者： xu yongchang WANG Xiaofeng SHI Baoguang The Key Laboratory of Gas Geochemistry Chinese Academy of Sciences Lanzhou 730000 China

In the 80’s of last century, based on the advances in natural gas exploration practice, the concepts of bio-thermocatalytic transitional-zone gas and early thermogenetic gas were proposed, and the lower limit Ro values for the formation and accumulation of thermogenetic natural gases of industrial importance have been extended to 0.3%–0.4%. In accordance with the two-stage model established on the basis of carbon isotope fractionation involved in the formation of coal-type natural gases, the upper limit Ro values of lowly evolved natural gases should be set at 0.8%–1.0%. This is the concept of low-mature gas which is commonly accepted at the present time. The Urengoy super-large gas field in western Siberian Basin is a typical example of low-mature gas field, where low-mature gas reserves account for 20% of the globally proven natural gas reserves, and this fully indicates the importance of this kind of resources. The proven reserves of natural gases in the Turpan-Hami Basin of China are approximate to 1000×108 m3, and the thermal evolution indices of source rocks are Ro=0.4%–0.8%. The δ13C1 values of methane are mainly within the range of -44‰– -39‰ (corresponding to Ro=0.6%–0.8%), and those of ethane are mainly within the range of -29‰– -26‰, indicating that these natural gases should be designated to the coal-type low-mature gases. The light hydrocarbon evolution indices of natural gases also provide strong evidence suggesting that they are the coal-type low-mature gases. If so, low-mature gas in the Turpan-Hami Basin has been accumulated to such an extent as to be equivalent to the total reserves of three large-sized gas fields, and their existence is of great significance in the study and exploration of China’s low-mature gases. If it is evidenced that the source rocks of low-mature gases are related mainly to coal measures, China’s abundant lowly evolved coal series resources will provide a huge resource potentiality for the generation of low-mature gases.

关键词：资源潜力低成熟气体

Innovation of experimental methodology for adsorbed gases on hydrocarbon-source rocks

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Chinese Journal Of Geochemistry 2013年第1期32卷 35-40页

作者： SHI Baoguang WANG Xiaofeng xu yongchang ZHEN Jianjing The Key Laboratory of Oil and Gas Resources Institute of Geology and Geophysics Chinese Academy of Sciences

As compared to the device developed by our predecessors, the newly developed adsorbed gas degasification-collection device has a series of advantages such as wide sample application range, large sample inlet, high vacuum, short-time sample smashing, low crushing temperature and water-free gas collection, which ensure the geochemical characteristics of acquired adsorbed gas samples to be the same as those of the adsorbed gases on corresponding hydrocarbon-source rocks. The results showed that the acquired adsorbed gases are composed mainly of hydrocarbon gas and carbon dioxide gas, with the hydrocarbon gas accounting for more than 80%, and can be measured reliably for their δ13C1-δ13C3 data, even δ13C4-δ13C5 data. The results of carbon isotope test and analysis satisfy the needs for the geochemical study and application of adsorbed gases. The above new techniques of experimental geochemistry are helpful for establishing the new direct natural gas-source correlation method, proving that the previous usual method of indirect natural gas-source correlation is scientific and authentic, thus providing the experimental basis for the study and application of adsorbed gases on hydrocarbon-source rocks.

关键词：气体收集烃源岩吸附地球化学特征实验地球化学创新验方应用程序

A model for carbon isotope distribution of methane duringdiagenesis

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Chinese Science Bulletin 1998年第7期43卷 576-578页

作者： Ping Guan yongchang xu Wenhui Liu Darui Wang Peking Univ Dept Geol Beijing 100871 Peoples R China Chinese Acad Sci Lanzhou Inst Geol Lanzhou 730000 Peoples R China Res Inst Petr Explorat & Dev Beijing 100083 Peoples R China

The evolution of methane carbon isotope with depth has been discussed based on diagenetic reaction kinetics and isotopic Rayleigh fractionational theory. A mathematical model to describe data of methane carbon isotope... 详细信息

关键词： methane carbon isotope maturity Rayleigh fractionation.

Low-mature gases and typical low-mature gas fields in China

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Science China Earth Sciences 2008年第2期51卷 312-320页

作者： xu yongchang WANG ZhiYong WANG XiaoFeng ZHENG JianJing DU HongYu Key Laboratory of Gas Geochemistry Chinese Academy of SciencesLanzhou 730000China Research Institute of Turpan-Hami Oil field Company Hami 839009China

No natural gas pool of industrial importance could be formed at the low-evolution stage of organic matter. In the 1980s, on the basis of the development in exploration practice, the hypotheses of bio-thermo-catalytic transitional zone gases and early thermogenic gases were proposed. The lower-limit Ro values for the formation and accumulation of natural gases of industrial importance have been expanded to 0.3%―0.4%. In the light of the two-stage model established on the basis of carbon isotope fractionation in coal-type natural gases, the upper-limit Ro values have been set at 0.8%―1.0%. In terms of the geological practice in the low-mature gas zones and China's main coal-type gas fields, it is feasible and proper to set the upper-limit Ro value of low-mature gases at 0.8%. Supper-large gas fields such as the Urengoy gas field in western Siberian Basin should belong to low-mature gas fields, of which the natural gas reserves account for more than 20% of the global proven reserves, providing strong evidence for the significance of such a type of resources. The proven natural gas reserves in the Turpan-Hami Basin of China have almost reached 1000 × 108 m3. The main source rocks in this area are the Jurassic Xishanyao Formation, which occurs as a suite of coal series strata. The corresponding thermal evolution indices (Ro ) are mainly within the range of about 0.4%―0.8%, the δ 13C1 values of methane vary between-44‰ and-39‰ (correspondingly Ro =0.6%―0.8%), and those of ethane are within the range of-29‰―-26‰, indicating that natural gases in the Turpan-Hami Basin should be designated to coal-type low-mature gases. The light hydrocarbon evolution indices of natural gases also fall within the area of low evolution while the precursor type of light hydrocarbons also shows the characteristics of the coal-type. The geological background, carbon isotopic composition and light hydrocarbon index all provide strong evidence suggesting that the proven natural gases in the Turpan

关键词： Turpan-Hami Basin natural gas low-mature gas humus isotope

Helium and argon isotope geochemistry of natural gases in China's petroliferous basins

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Chinese Journal Of Geochemistry 2011年第1期30卷 19-32页

作者： LIU Wenhui xu yongchang TAO Mingxin ZHANG Xiaobao Key Laboratory of Petroleum Resources Research Institute of Geology and Geophysics Chinese Academy of Sciences Lanzhou730000 China Research Institute of Petroleum Exploration and Production SINOPEC Beijing 100083 China Key Laboratory of Environmental Change and Natural Disaster of Ministry of Education College of Resource Science andTechnology Beijing Norma University Beijing 100875 China

The age-accumulation effect of 40Ar in hydrocarbon source rocks was discussed in accordance with the decay law of radioactive elements. In terms of the mean values of 40Ar/36Ar, the old Sinian gas reservoirs (mean values of 40Ar/36Ar: 7009) were definitely distinguished from the Permian gas reservoirs (mean values of 40Ar/36Ar: 1017) in Weiyuan, Sichuan Province, and the gas source of the Permian gas reservoir (mean values of 40Ar/36Ar: 5222) in well Wei-7 with the Weiyuan structure is defined as the Sinian system. Based on the values of 40Ar/36Ar, the coal-type gases (The source rocks are of the C-P system; mean values of 40Ar/36Ar: 1125) are definitely distinguished from the oil-type gases (The source rocks are of the Tertiary system; mean values of 40Ar/36Ar: 590) in the Tertiary reservoirs of the Zhongyuan Oilfield. Besides, 40Ar/36Ar values also have a positive effect on the oil-source correlation of oil reservoirs in ancient hidden mountains. According to the crust-mantle interchange information reflected by 3He/4He values, petroliferous provinces in China can be divided into three major tectonic regions. (1) The eastern active region: The crust-mantle volatile matter exchanges actively, and the 3He/4He values are mainly around 10-6, partly around 10-7. (2) The central stable region: The 3He/4He values are all around 10-8. (3) The western sub-stable region: The 3He/4He values are mainly around 10-8, and around 10-7 on the edges of the basins. Helium contents of some gas wells in China’s eastern petroliferous region reach the industrial abundance (He≈0.05%–0.1%), the 3He/4He values reach 10-6, and the equivalent values for the mantle-source components in helium gas can reach 30%–50%. As viewed from this, a new type of crust-mantle composite helium resources has been proposed. Geneses of some CO2 gas reservoirs in the east of China and some issues concerning mantle-source methane were discussed in the light of the helium and carbon isotopes of CO2 and CH4 in nat

关键词：中国东部地区含油气盆地天然气井同位素地球化学氦气气藏成因甲烷碳同位素区域构造运动

A breakthrough of researching reservoir adsorption gas and its significance

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Chinese Science Bulletin 1999年第8期44卷 761-763页

作者： yongchang xu Xiaobao Zhang Ping Shen Wenhui Liu Chinese Acad Sci State Key Lab Gas Geochem Lanzhou 730000 Peoples R China

GC-C-MS on linear isotope analysis equipment makes it possible to measure the hydrocarbon gases at the level of 10 -3-10 -2 μL- By applying this technique the carbon isotopes of C1-C3 of the adsorbed gas from the Triassic oil sand bed of the Aican-l Well in the Turpan-Hami basin were analysed. The δ13C values of C1-C3, are -55.1‰, -38.6‰ and -35.0‰ respectively. In terms of geochemical characteristics of natural gases and crude oils, in combination with basinal geological backgrounds, it is considered that the reservoir adsorbed gas was formed by crude-oil biodegradation, absorbed by reservoir rocks and its oil-gas source is related with the Permain (perhaps including the Carboniferous). The adsorbed gas is obviously different from the Jurassic coal-generated oil and gas.

关键词： adsorbed gas carbon isotope oil-gas source correlation.

Isotopic composition charac-teristics and identification of immature and low-mature oils

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Chinese Science Bulletin 2001年第22期46卷 1923-1929页

作者： xu yongchang SHEN Ping LIU Wenhui GUAN Ping HUANG Difan State Key Laboratory of Gas Geochemistry Lanzhou Institute of GeologyChinese Academy of SciencesLanzhou 730000China Department of Geology Peking UniversityBeijing 100871China Institution of Exploration&Development China Petroleum&NaturalGas Corporation LimitedBeijing 100083China

Isotopic composition characteristics and the significance of immature and low-mature oils are first systematically discussed. The carbon isotopes of the whole oil can be divided into two groups, one has δ13C main peak values ranging from -30‰ to -29 and the other from -27‰ to -25‰, they are related to lacustrine and salt-lake facies or swamp facies, respectively. The carbon isotopic fractionation among different group components is relatively small, usually less than 2‰ and the biggest difference in fractionation often occurs between saturated and aromatic fractions. Their δD values vary between -180‰ and -130‰. The main peak of their δD values concentrates between -170‰ and -150‰, suggesting a domination of lacustrine facies. However, the secondary peak ranges from -160‰ to -150‰, showing a frequent salinization of paleo-water bodies. The average δ13C values of the methane vary between -50‰ and -52‰, about 10‰ lighter than those of mature oils. There is a relatively good

关键词： immature and low-mature oil isotope associated gas.

Geochemical characteristics of light hydrocarbons in natural gases from the Turpan-Hami Basin and identification of low-mature gas

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Chinese Science Bulletin 2010年第29期55卷 3324-3328页

作者： SHEN Ping WANG XiaoFeng WANG ZhiYong MENG QianXiang xu yongchang State Key Laboratory of Oil and Gas Resources Research Chinese Academy of Sciences Lanzhou 730000 China Institute of Exploration and Development Tu-Ha Oilfield Company of China Hami 839009 China

Theoretical and practical knowledge regarding low-mature gasses is of significant importance to identifying potential natural gas *** hydrocarbon parameters and C and H isotopes are useful tools to identify low-mature *** gas samples were collected from the Turpan-Hami Basin for light hydrocarbon *** results showed that the light hydrocarbon components of natural gases contain high methylcycloxane,high isoparaffin and low *** implies that the gas-generating parent materials are of typical humus type and the paleoenvironment is a fresh water sedimentary *** features are consistent with the geological setting of the *** studies of isoheptane,heptane,and the carbon isotopic compositions of methane in natural gases,and other maturity indices indicated that natural gases in the Turpan-Hami Basin are dominated by low-mature gas formed during the low evolution stage of Jurassic coal *** parent materials are of type III,and the maturation degree was in the low evolution *** are the fundamental characteristics of low-mature *** of light hydrocarbon research provided further evidence to suggest that the Turpan-Hami Basin is a large-scale gas producer of low-mature gas in *** is likely that this resource will play an important role in future exploration and development of low-mature gas in China.

关键词：天然气资源地球化学特征吐哈盆地轻烃参数低熟气碳同位素组成鉴定母质类型