28 April 2014, Volume 32 Issue 12

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    Spescial Issues
  • LIU Hui, WU Huiling, LIU Weicheng, LI Jinjin, CHEN Baohua, WANG Linsong
    Abstract ( ) Download PDF ( ) HTML   Knowledge map   Save
    Streptomyces lydicus A01 is isolated from the soil of the suburban vegetable field in Beijing (China), and it shows a strong inhibitory activity against several plant pathogenic fungi. In order to detect the activity of the erythromycin promoter (ermE*) in Streptomyces lydicus A01, and to obtain the labeled strain for further research, the egfp 720 bp and rfp 678 bp segments are inserted into the expression vector pIB139 separately, the recombinant vectors pIB139-EGFP and pIB139-RFP are successfully obtained. The pIB139-EGEP and pIB139-REP are transformed into Streptomyces lydicus A01 strain by intergeneric conjugation. Transformants are identified by the fluorescence observation with microscope. It is shown that the two recombinant vectors are successfully integrated into the strain A01, and that the ermE* promoter could induce egfp and rfp gene expression in Streptomyces lydicus A01.
  • LIU Ting, LU Caige, HUA Yupeng, LIU Dewen, LIU Weicheng
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    In order to improve the fermentation process of natamycin by Streptomyces lydicus A02, the main parameters for the fed batch fermentation are optimized. The range of suitable pH values is screened by an assisted optimization using a shaker with the function of automatic feeding to regulate pH values. Then the experiments in 30 L fermentor are carried out by controlling pH values within the suitable range as the main regulation point. The relationship between the natamycin yields and the fermentation parameters is obtained through the software Biostar 5.0. It is shown that the optimized parameter combination for the fed batch fermentation of natamycin by S. lydicus A02 is as follows: The culture temperature is 30℃, the pH value is 6.25-6.29, the DO is 20%-30%, the OUR is 25-15 mmol/(L·h), the CER is 20-12 mmol/(L·h), the amino-N is 0.20-0.23 g/L, and the reducing sugar remains at about 1.5% in 88 h then drops gradually to 0.32% at 112 h, the end of fermentation, when the natamycin yield is up to 2.02 g/L in the supernatant and 6.98 g/L in the total fermented broth. It can be concluded that the fermentation level of natamycin by S. lydicus A02 could be increased effectively by the optimization of the main fermentation parameters.
  • ZHANG Taotao, LIU Weicheng, WU Huiling, DONG Dan, LIU Ting
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    The solid fermentation of Gliocladium roseum ACM941 has not been well studied so far,this paper proposes to improve the fermentation titer of ACM941 through the single factor and orthogonal design. The optimum fermentation conditions are obtained as follows: The bran and cottonseed shell ratio is 4:6, the corn flour 2%, the oat flour 2%, the beef extract 3%, and the peptone 2%. The optimum mycelial growth and sporulation temperatures are 25℃ and 20℃. The initial water content is 30% and the inoculation volume is 6%. Under these conditions, the maximum conidial yield comes to 1.17×109 cfu/g, 12.4 times higher than the initial fermentation level. This provides a support for the development of the biocontrol agent.
  • TIAN Zhaofeng, LU Xiangyang, HOU Lingyu, LUO Chen, CHAI Min
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    To assess the resistance level of the new anti-virus tomato variety against tomato yellow leaf curl virus, the time of the virus affection, the disease incidence and the disease index of 18 tomato varieties are recorded in the field by the natural transmission with Jinpeng 1 and Jinman as the susceptible control. The resistance level is evaluated by PCR and ELISA. It is shown that the resistance varies significantly among the 18 tomato varieties. Two cultivars of Jinpeng1and Jinman are very susceptible, the disease incidences both reach 100% and the disease indices are both above 65.2. Three cultivars of Qiuguang 15-6, PC-88, and Qiuguang 69 show a high level resistance, the disease incidences and the disease indices are all 0. The rest 13 cultivars show different degrees of resistance levels, the disease incidences and the disease indices are between 5.6% and 45.2%, and 2.6 and 18.0, respectively.
  • ZHANG Xun, ZHOU Yingying, LI Yan, FU Xuechi, LIU Yuyan, CHEN Zhan, CHEN Jian, ZHAO Ronghua, LIU Qishan, ZHANG Yi, GAO Lingwang, WANG Qi
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    Apolygus lucorum (Meyer-Dür.) and Erythroneura apicalis (Nawa) are important pests that affect the quality and the yield of grapevine and cause huge economic losses. This paper focuses on the selection of effective botanical pesticides to control A. lucorum and E. apicalis. This experiment explores the effect of several botanical pesticides for A. lucorum and E. apicalis, including the 0.5% veratrine, the 0.6% Oxygen·Lactone agent, the 5% natural pyrethrin, the composite neem pesticide, the rotenone and the composite nicotine. The 0.5% veratrine shows a stable control efficacy, which is higher than 60% in Chengdu, while the composite nicotine shows the highest efficacy against A. lucorum, which is above 70%. In Yinchuan, the 0.5% veratrine shows the highest efficacy, against the first generation adults and the second generation larvae of E. apicalis, while the 5% natural pyrethrin shows 100% control efficacy against E. apicalis in Nanjiang. The 0.5% veratrine and the composite neem could be used as effective pesticides to control A. lucorum and the 5% natural pyrethrin can be used to control E. apicalis. They could be widely used in the production of pollution-free grapes.
  • Articles
  • ZHOU Xiaofeng, NIU Xiaobing, WANG Jianguo, LIANG Xiaowei
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    The diagenesis and porosity evolution of the oil-bearing sandstone in Chang 8 of Longdong oil-producing region are analyzed by means of casting thin-sections, X-ray diffraction data, scanning electron micrograph observation and physical properties. The oil-bearing sandstone is currently at the first stage of the middle-diagenesis period. It went through strong compaction and violent cementation and weak dissolution, which led to the tight sandstone reservoir. The porosity loss rate of the compaction is 38.9%, the porosity loss rate of the cementation is 38.0%, and the porosity of the dissolution is only 3.9%. The porosity evolution during the diagenesis shows that the primary porosity is 37.3%, the residual intergranular porosity after the compaction and the cementation of the early diagenesis process is 17.9%, the porosity of the first oil charging process is 17.0%, and the porosity of the second oil charging process is only 12.5%, which illustrates that the densification of the oilbearing sandstone occurred between the first oil charging process and the second oil charging process of the middle-diagenesis period.
  • WU Xiaobin, HOU Jiagen, WANG Daxing, CUI Zhilin, LI Shuqing
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    In order to study the distribution of the internal residual oil in a beach-bar sand body, and to reveal the interbed development pattern, the mud interlayer should be described quantitatively. This paper considers three interbed types of bar sand bodies, using the core data, the logging data in the Gangzhong oilfield and the sedimentation investigation results in Qinghai Lake. With a 3D architecture model and the principle of the dip angle measurement, a new approach of calculating the dip angle of the interbed within a single bar sand body is proposed: Scanning of the maximum along the interface in the 3D model. The twin well spacing calculation method is improved. The development pattern of the interbed is obtained by using a quantitative description of the interlayer. A new understanding of the interbed of the bar sand body is achieved. In the Gangzhong oilfield, the muddy interbed is mainly developed within a single bar sloping to the center of the basin, and the dip angle is between 2°and 5°. Meanwhile, there is one muddy interbed every 70 m. The scale of the hyperplasia sandbody is about 60-90 m.
  • ZHANG Qiaoliang, CHU Shasha, JIANG Ping, XU Yueming, PENG Wenfeng, LI Ming
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    WZF4 oilfield is located in the Beibu Gulf in the South China Sea area, including the oil-bearing formation for the group of WZ and the group of L. The group of WZ contains high permeability reservoirs, and is fully developed. The logging interpretation results show considerable reserves for the group of L, with the low permeability reserves up to 82%. The development experience for the group of WZ is not applicable to the group of L. The group of L has the problems of heterogeneity, complicated micro pore structure and difficult water injection. The microscopic pore structure and the distribution of the oil-water displacement of reservoirs are obtained by the experiment technologies of the constant rate mercury, the NMR and the physical simulation of the oil-water displacement. It is shown that the reservoir permeability is 1×10-3-5×10-3μm2 for the group of L. When the reservoir permeability is below 2×10-3μm2, most throats are less than 1 μm, the filtration resistance is high and the water flooding development is difficult. For the low permeability reservoir, the high formation pressure can significantly improve the displacement efficiency. The residual oil phase permeability is lower than 0.2, the water injection pressure is high, and the small moderate injection is conducive to the effective injection, and keeps a high imbibition efficiency, to improve the reservoir recovery.
  • CHEN Jie
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    Taking the semi-weathered rock of unconformity of Xia9 wellblock in Junggar Basin as an example, several types of diagenesis are studied by combining a qualitative analysis with a quantitative evaluation, consisting of compaction, dissolution, cementation, replacement and fracture. The main diagenesis, which influences the physical character of the reservoirs, involves compaction, cementation, dissolution and fracturing. Compaction and cementation reduce pores, dissolution and fracturing increase pores. On the basis of numerous core observations and experimental data, a strong heterogeneity of the digenesis is found both on the plane and on the section in semi-weathered rock of unconformity. After that, the standard of several diagenesis strength parameters is established for the quantitative evaluation of diagenesis strength. The impact of compaction is strong on the original pores, whose level is high. The cement, found mostly as siderite, blocks plenty of pores,and its level is low. The proportion of the type of the dissoluted pore is high, and the dissolution level is high, and the fractureing level is low with few fractures. The order of diagenesis is made based on the strength of diagenesis on the impacts on the porosity of the semi-weathered rock. The sequences about the effect levels of the four kinds of diagenesis are as follows: compaction> dissolution> cementation> fracturing in study area.
  • YUAN Yongbin, YANG Jing, ZHANG Jianpei, YU Xu
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    The pattern classification process involves the learning from the original training samples, which easily leads to privacy disclosure. In order to avoid the leaks of privacy in the pattern classification process and not to affect the performance of the algorithm, this paper proposes a pattern classification privacy preserve algorithm based on the primary component analysis (PCA). This algorithm extracts the principal component of the original training data and converts the original training samples to new samples corresponding to the primary components. Then, a classification model is trained on the new samples. Experiments are carried out on the Adult data set and the KDD CUP 99 data set, and the precision and recall indexes are used to evaluate the proposed algorithm. It is shown that this algorithm can avoid the leakage of the original attributes through extracting the principal components of the feature attributes about the raw data. PCA can achieve de-noising to some extent, so that the classification performance on the classifier is better than that on the original data set. Therefore, compared with the existing algorithms, this algorithm has better pattern classification accuracy and privacy preserve performance.
  • Reviews
  • CHENG Senping, XIA Yankai, HANG Bo
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    The thirdhand smoke (THS) is a new concept, so far unfamiliar to most people. It refers to the tobacco smoke toxicants that remain in indoor surfaces and in dust particles after the cigarettes are extinguished. Certain chemical constituents such as nicotine in the THS can react with atmospheric species to generate secondary hazardous products. The THS becomes more toxic during the aging process. The THS poses a great hazard to infants and young children who live with the smokers. This paper reviews the relationship and differences between the THS and the secondhand smoke (SHS). The physical and chemical properties, as well as the common pollution locations and exposure routes of the THS are discussed. The research progresses concerning the THS in recent years with respect to its composition and chemical transformation, the environmental and biological monitoring, and the cellular/tissue and genetic toxicity are reviewed. Finally, the future research directions and clinical implications of the THS exposure are commented. It is believed that the promotion of the THS concept based on scientific findings will impose a positive impact on the social, economic, and policy-making aspects of the overall tobacco control. How to prevent and cleanup the THS would also be of interest to the general public.