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| 1 | Identification and bioinformatics analysis of lactate dehydrogenase genes from Echinococcus granulosus显示文摘Objective:To identify full length cDNA sequence of lactate dehydrogenase(LDH) from adult Echinococcus granulosus(E.granulosus) and to predict the structure and function of its encoding protein using bioinformatics methods.Methods:With the help of NCBI,EMBI, Expasy and other online sites,the open reading frame(ORF),conserved domain,physical and chemical parameters,signal peptide,epitope,topological structures of the protein sequences were predicted and a homology tertiary structure model was created:Vector NT1 software was used for sequence alignment,phylogenetic tree construction and tertiary structure prediction. Results:The target sequence was 1 233 bp length with a 996 bp biggest ORF encoding 331 amino acids protein with typical L-LDH conserved domain.It was confirmed as full length cDNA of LDH from E.granulosus and named as EgLDH(GenBank accession number:HM748917).The predicted molecular weight and isoelectric point of the deduced protein were 3 5516.2Da and 6.32 respectively.Compared with LDHs from Taenia solium,Taenia saginata asiatica,Spirometra erinaceieuropaei.Schistosoma japonicum,Clonorchis sinensis and human,it showed similarity of 86% ,85% ,55% ,58% ,58% and 53% ,respectively.EgLDH contained 3 putative transmembrane regions and 4 major epitopes(54aa-59aa.81aa-87aa,97aa-102aa,307aa-313aa),the latter were significant different from the corresponding regions of human LDH.In addition,some NAD and substrate binding sites located on epitopes 54aa-59aa and 97aa-102aa,respectively.Tertiary structure prediction showed that 3 key catalytic residues 105R,165D and 192H forming a catalytic center near the epitope 97aa-102aa,most NAD and substrate binding sites located around the center.Conclusions:The full length cDNA sequences of EgLDH were identified.It encoded a putative transmembrane protein which might be an ideal target molecule for vaccine and drugs. | Gang Lu Yajun Lu Lihua Li Lixian Wu Zhigang Fan Dazhong Shi Hu Wang Xiumin Han | 2010 | Asian Pacific Journal of Tropical Medicine2010，3，10： | 2 |
| 2 | Characterization of natural fractures in deep-marine shales: a case study of the Wufeng and Longmaxi shale in the Luzhou Block Sichuan Basin, China显示文摘Natural fractures are of crucial importance for oil and gas reservoirs,especially for those with ultralow permeability and porosity.The deep-marine shale gas reservoirs of the Wufeng and Longmaxi Formations are typical targets for the study of natural fracture characteristics.Detailed descriptions of full-diameter shale drill core,together with 3D Computed Tomography scans and Formation MicroScanner Image data acquisition,were carried out to characterize microfracture morphology in order to obtain the key parameters of natural fractures in such system.The fracture type,orientation,and their macroscopic and microscopic distribution features are evaluated.The results show that the natural fracture density appears to remarkably decrease in the Wufeng and Longmaxi Formations with increasing the burial depth.Similar trends have been observed for fracture length and aperture.Moreover,the natural fracture density diminishes as the formation thickness increases.There are three main types of natural fractures,which we interpret as(I)mineral-filled fractures(by pyrite and calcite),i.e.,veins,(II)those induced by tectonic stress,and(III)those formed by other processes(including diagenetic shrinkage and fluid overpressure).Natural fracture orientations estimated from the studied natural fractures in the Luzhou block are not consistent with the present-day stress field.The difference in tortuosity between horizontally and vertically oriented fractures reveals their morphological complexity.In addition,natural fracture density,host rock formation thickness,average total organic carbon and effective porosity are found to be important factors for evaluating shale gas reservoirs.The study also reveals that the high density of natural fractures is decisive to evaluate the shale gas potential.The results may have significant implications for evaluating favorable exploration areas of shale gas reservoirs and can be applied to optimize hydraulic fracturing for permeability enhancement. | Shasha SUN Saipeng HUANG Enrique GOMEZ-RIVAS Albert GRIERA ΒοLIU Lulu XU Yaru WEN Dazhong DONG Zhensheng SHI Yan CHANG Yin XING | 2023 | Frontiers of Earth Science2023，17，1： | 0 |
| 3 | Laminae characteristics of gas-bearing shale fine-grained sediment of the Silurian Longmaxi Formation of Well Wuxi 2 in Sichuan Basin,SW China显示文摘Based on various test data, the composition, texture, structure and lamina types of gas-bearing shale were determined based on Well Wuxi 2 of the Silurian Longmaxi Formation in the Sichuan Basin. Four types of lamina, namely organic-rich lamina, organic-bearing lamina, clay lamina and silty lamina, are developed in the Longmaxi Formation of Well Wuxi 2, and they form 2 kinds of lamina set and 5 kinds of beds. Because of increasing supply of terrigenous clasts and enhancing hydrodynamics and associated oxygen levels, the contents of TOC and brittle mineral reduce and content of clay mineral increases gradually as the depth becomes shallow. Organic-rich lamina, organic-rich + organic-bearing lamina set and organic-rich bed dominate the small layers 1-3 of Member 1 of the Longmaxi Formation, suggesting anoxic and weak hydraulic depositional setting. Organic-rich lamina, along with organic-bearing lamina and silty lamina, appear in small layer 4, suggesting increased oxygenated and hydraulic level. Small layers 1-3 are the best interval and drilling target of shale gas exploration and development. | SHI Zhensheng QIU Zhen DONG Dazhong LU Bin LIANG Pingping ZHANG Mengqi | 2018 | Petroleum Exploration and Development2018，45，2： | 0 |
| 4 | Favorable lithofacies types and genesis of marine- continental transitional black shale: A case study of Permian Shanxi Formation in the eastern margin of Ordos Basin, NW China显示文摘Based on core description,thin section identification,X-ray diffraction analysis,scanning electron microscopy,low-temperature gas adsorption and high-pressure mercury intrusion porosimetry,the shale lithofacies of Shan23 sub-member of Permian Shanxi Formation in the east margin of Ordos Basin was systematically analyzed in this study.The Shan23 sub-member has six lithofacies,namely,low TOC clay shale(C-L),low TOC siliceous shale(S-L),medium TOC siliceous shale(S-M),medium TOC hybrid shale(M-M),high TOC siliceous shale(S-H),and high TOC clay shale(C-H).Among them,S-H is the best lithofacies,S-M and M-M are the second best.The C-L and C-H lithofacies,mainly found in the upper part of Shan23 sub-member,generally developed in tide-dominated delta facies;the S-L,S-M,S-H and M-M shales occurring in the lower part of Shan23 sub-member developed in tide-dominated estuarine bay facies.The S-H,S-M and M-M shales have good pore struc-ture and largely organic matter pores and mineral interparticle pores,including interlayer pore in clay minerals,pyrite inter-crystalline pore,and mineral dissolution pore.C-L and S-L shales have mainly mineral interparticle pores and clay mineral in-terlayer pores,and a small amount of organic matter pores,showing poorer pore structure.The C-H shale has organic mi-cro-pores and a small number of interlayer fissures of clay minerals,showing good micro-pore structure,and poor meso-pore and macro-pore structure.The formation of favorable lithofacies is jointly controlled by depositional environment and diagen-esis.Shallow bay-lagoon depositional environment is conducive to the formation of type II2 kerogen which can produce a large number of organic cellular pores.Besides,the rich biogenic silica is conducive to the preservation of primary pores and en-hances the fracability of the shale reservoir. | WU Jin WANG Hongyan SHI Zhensheng WANG Qi ZHAO Qun DONG Dazhong LI Shuxin LIU Dexun SUN Shasha QIU Zhen | 2021 | Petroleum Exploration and Development2021，48，6： | 0 |
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