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Science in China. Series B, Chemistry, life sciences & earth sciences最新文献

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密度泛函理论下的分子电负性——I.由电负性均衡原理直接计算分子中的原子电荷 密度泛函理论下的分子电负性——I.由电负性均衡原理直接计算分子中的原子电荷
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-02-10 DOI: 10.1360/ZB1995-25-2-126
杨忠志 沈尔忠, Yang Zhong-Zhi Chen Er-Zhong
{"title":"密度泛函理论下的分子电负性——I.由电负性均衡原理直接计算分子中的原子电荷","authors":"杨忠志 沈尔忠, Yang Zhong-Zhi Chen Er-Zhong","doi":"10.1360/ZB1995-25-2-126","DOIUrl":"https://doi.org/10.1360/ZB1995-25-2-126","url":null,"abstract":"以密度泛函理论表述的电负性及其均衡原理为基础,以组成原子电负性的调和平均为分子电负性参考取值,提出和设计了直接计算分子中原子电荷分布的新方案,避免了原算法中的多元回归和参数的多重选择,给出了分子环境下原子电负性和硬度的价态标度.本方案能更简便广泛的应用于大分子中原子电荷分布的计算,结果与ab initio STO-3G的结果符合相当好.","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"22 1","pages":"126-131"},"PeriodicalIF":0.0,"publicationDate":"1995-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76616412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Purification and partial amino acid sequences of a new presynaptic toxin and a cytotoxin from venom of pit veper Agkistrodon blomhoffii brevicaudus. 短尾蝮蛇毒液一种新的突触前毒素和细胞毒素的纯化及部分氨基酸序列分析。
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-02-10 DOI: 10.1360/YB1995-38-2-169
Y. Ji, L. Lu, K. Xu, H. Hattori, S. Terakawa
{"title":"Purification and partial amino acid sequences of a new presynaptic toxin and a cytotoxin from venom of pit veper Agkistrodon blomhoffii brevicaudus.","authors":"Y. Ji, L. Lu, K. Xu, H. Hattori, S. Terakawa","doi":"10.1360/YB1995-38-2-169","DOIUrl":"https://doi.org/10.1360/YB1995-38-2-169","url":null,"abstract":"The technique of the reverse-phase performance liquid chromatography (RP-HPLC) was employed to separate and purify the toxic proteins from the venom of Agkistrodon blomhoffii brevicaudus collected in China. 3 toxic proteins marked as AgTx-1, AgTx-2 and AgTx-3 consisting of about 122 amino acid residues were screened. The toxicities (LD50) of the AgTx-1, AgTx-2 and AgTx-3 were 0.075, 0.51 and 6.6 mg per kg weight of mice respectively. Toxicological experiment in the chick biventer cervicis nerve-muscle preparation showed that the acetylcholine (Ach) sensitivity of the preparation was unchanged after the total failure of the indirect contraction caused by AgTx-1 and AgTx-2, suggesting that they were presynaptic blockers, namely beta-type of snake toxins. However, the amplitude of indirect contraction of the preparation was gradually reduced due to its incomplete relaxation caused by AgTx-3, indicating that it should belong to the category of cytotoxins. The partial amino acid sequences of 3 toxins have been established. It was found in ref. [1] that the sequences of the first 32 N-terminal amino acid residues of AgTx-1 and AgTx-2, as well as beta-agkistrodotoxin (beta-AgTx) reported previously were identical (the residue at the position 30 of beta-AgTx should be Trp). In view of the similarity in toxicities, and the amounts in the venom and other properties, it was concluded that AgTx-1 should be beta-AgTx and consequently was renamed beta 1-AgTx. AgTx-2 should be the isoform of beta 1-AgTx, and correspondingly named beta 2-AgTx.","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"23 1","pages":"169-78"},"PeriodicalIF":0.0,"publicationDate":"1995-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79298828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 6
飞蝗对低频声信号加工的胞内研究——尾铗-巨中间神经元系统的结构与功能 飞蝗对低频声信号加工的胞内研究——尾铗-巨中间神经元系统的结构与功能
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-02-10 DOI: 10.1360/ZB1995-25-2-179
徐智敏 沈钧贤, XU Zhi-Min Chen Jun-Xian
{"title":"飞蝗对低频声信号加工的胞内研究——尾铗-巨中间神经元系统的结构与功能","authors":"徐智敏 沈钧贤, XU Zhi-Min Chen Jun-Xian","doi":"10.1360/ZB1995-25-2-179","DOIUrl":"https://doi.org/10.1360/ZB1995-25-2-179","url":null,"abstract":"利用胞内电生理记录及染料标记技术,首次揭示了飞蝗末端腹神经节中与低频声接收有关的尾铗-巨中间神经元系统的结构与功能.该系统包含双侧对称的四对巨中间神经元(giant interneuron,GI1~4),每个GI均有各自独特的树突分枝构型,细胞体位置,及主轴突的定位与朝向;并揭示了该系统对低频声刺激的反应特征:放电模式、反应阈值-刺激频率关系曲线、强度特征,以及对刺激频率的编码方式,讨论了飞蝗尾铗-巨中间神经元系统在低频声通信方面的可能作用.","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"33 1","pages":"179-187"},"PeriodicalIF":0.0,"publicationDate":"1995-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86294238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
YBa 2 Cu 3 O 7 原子簇自洽晶体场的量子化学全电子从头计算 YBa 2 Cu 3 O 7 原子簇自洽晶体场的量子化学全电子从头计算
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-02-10 DOI: 10.1360/ZB1995-25-2-132
陈念贻 刘洪霖, Chen Nian-Yi Liu Hong-Lin
{"title":"YBa 2 Cu 3 O 7 原子簇自洽晶体场的量子化学全电子从头计算","authors":"陈念贻 刘洪霖, Chen Nian-Yi Liu Hong-Lin","doi":"10.1360/ZB1995-25-2-132","DOIUrl":"https://doi.org/10.1360/ZB1995-25-2-132","url":null,"abstract":"应用全电子HF从头计算自洽场和自洽晶体场方法计算了原子簇YBa 2 Cu 3 O 7 提出了HF表面势使非对称的原子簇具有较对称的势场,得到较为对称的电子结构、电荷分布、前线轨道和键级等信息,讨论了YBa 2 Cu 3 O 7 的化学键性质.认为单胞内存在着以共价键相连的[CuO 2 —O—CuO—O—CuO 2 ) 6.8- 的络合离子,而单胞间在c方向由离子键相连接;强调了顶角氧对CuO 2 面空穴状态的重要影响.","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"85 1","pages":"132-136"},"PeriodicalIF":0.0,"publicationDate":"1995-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78543367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Chinese squash leaf curl virus: a new whitefly-transmitted geminivirus. 中国南瓜卷叶病毒:一种新的白蛉传播的双病毒。
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-02-10 DOI: 10.1360/YB1995-38-2-179
Y. Hong, X. Wang, B. Tian, J. Cai
{"title":"Chinese squash leaf curl virus: a new whitefly-transmitted geminivirus.","authors":"Y. Hong, X. Wang, B. Tian, J. Cai","doi":"10.1360/YB1995-38-2-179","DOIUrl":"https://doi.org/10.1360/YB1995-38-2-179","url":null,"abstract":"Coat protein (CP) gene of the Chinese squash leaf curl virus (SqLCV-C) was amplified through PCR, cloned and completely sequenced. Based on the comparisons at the levels of both CP gene nucleotide and CP-deduced amino acid sequences with other geminiviruses, SqLCV-C is confirmed to be distinct from the American squash leaf curl virus (SqLCV-E). It is a new geminivirus transmitted by whitefly Bemisia tabaci, which infects dicotyledonous plants and is more closely related to the Indian cassava mosaic virus (ICMV).","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"43 1","pages":"179-86"},"PeriodicalIF":0.0,"publicationDate":"1995-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86536474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 23
Purification and partial amino acid sequences of a new presynaptic toxin and a cytotoxin from venom of pit veper Agkistrodon blomhoffii brevicaudus. 短尾蝮蛇毒液一种新的突触前毒素和细胞毒素的纯化及部分氨基酸序列分析。
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-02-01
Y Ji, L Lu, K Xu, H Hattori, S Terakawa
{"title":"Purification and partial amino acid sequences of a new presynaptic toxin and a cytotoxin from venom of pit veper Agkistrodon blomhoffii brevicaudus.","authors":"Y Ji,&nbsp;L Lu,&nbsp;K Xu,&nbsp;H Hattori,&nbsp;S Terakawa","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The technique of the reverse-phase performance liquid chromatography (RP-HPLC) was employed to separate and purify the toxic proteins from the venom of Agkistrodon blomhoffii brevicaudus collected in China. 3 toxic proteins marked as AgTx-1, AgTx-2 and AgTx-3 consisting of about 122 amino acid residues were screened. The toxicities (LD50) of the AgTx-1, AgTx-2 and AgTx-3 were 0.075, 0.51 and 6.6 mg per kg weight of mice respectively. Toxicological experiment in the chick biventer cervicis nerve-muscle preparation showed that the acetylcholine (Ach) sensitivity of the preparation was unchanged after the total failure of the indirect contraction caused by AgTx-1 and AgTx-2, suggesting that they were presynaptic blockers, namely beta-type of snake toxins. However, the amplitude of indirect contraction of the preparation was gradually reduced due to its incomplete relaxation caused by AgTx-3, indicating that it should belong to the category of cytotoxins. The partial amino acid sequences of 3 toxins have been established. It was found in ref. [1] that the sequences of the first 32 N-terminal amino acid residues of AgTx-1 and AgTx-2, as well as beta-agkistrodotoxin (beta-AgTx) reported previously were identical (the residue at the position 30 of beta-AgTx should be Trp). In view of the similarity in toxicities, and the amounts in the venom and other properties, it was concluded that AgTx-1 should be beta-AgTx and consequently was renamed beta 1-AgTx. AgTx-2 should be the isoform of beta 1-AgTx, and correspondingly named beta 2-AgTx.</p>","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"38 2","pages":"169-78"},"PeriodicalIF":0.0,"publicationDate":"1995-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18756093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Chinese squash leaf curl virus: a new whitefly-transmitted geminivirus. 中国南瓜卷叶病毒:一种新的白蛉传播的双病毒。
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-02-01
Y Hong, X Wang, B Tian, J Cai
{"title":"Chinese squash leaf curl virus: a new whitefly-transmitted geminivirus.","authors":"Y Hong,&nbsp;X Wang,&nbsp;B Tian,&nbsp;J Cai","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Coat protein (CP) gene of the Chinese squash leaf curl virus (SqLCV-C) was amplified through PCR, cloned and completely sequenced. Based on the comparisons at the levels of both CP gene nucleotide and CP-deduced amino acid sequences with other geminiviruses, SqLCV-C is confirmed to be distinct from the American squash leaf curl virus (SqLCV-E). It is a new geminivirus transmitted by whitefly Bemisia tabaci, which infects dicotyledonous plants and is more closely related to the Indian cassava mosaic virus (ICMV).</p>","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"38 2","pages":"179-86"},"PeriodicalIF":0.0,"publicationDate":"1995-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18756650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
cDNA cloning and sequence analysis of NIb gene of soybean mosaic virus. 大豆花叶病毒 NIb 基因的 cDNA 克隆和序列分析。
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-02-01
J Liu, X Peng, K Mang
{"title":"cDNA cloning and sequence analysis of NIb gene of soybean mosaic virus.","authors":"J Liu, X Peng, K Mang","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>cDNA of soybean mosaic virus (Beijing isolate, SMV-BJ) has been synthesized, using viral genomic RNA as a template and random hexanucleotides as primers. Based on the sequences of SMV-BJ coat protein (CP) gene as well as SMV- and WMV-II-related regions, oligonucleotides were made as primers for polymerase chain reaction (PCR). NIb gene of SMV-BJ was amplified by PCR, and cloned into pBluescript SK. The complete sequence was determined. The comparison of NIb genes between SMV-BJ and WMV-II (USA) shows that similarities for nucleotide sequence reach 80.3%; and the deduced amino acid sequence, 91.3%. In consideration of the high identities in between the CP gene and the 3'-non-coding region between them, WMV-II might be considered as a watermelon strain of SMV. Besides, some unexpected sequences were found in the 3'-region of 2 NIb gene clones. Following modification and splicing, a binary vector of NIb gene has been constructed for its expression in higher plant for the purpose of studying the possible replicase-mediated resistance in polyviruses.</p>","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"38 2","pages":"160-8"},"PeriodicalIF":0.0,"publicationDate":"1995-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18756092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
V-J junctional sequences of T cell receptor gamma gene in acute lymphocytic leukemia. 急性淋巴细胞白血病中T细胞受体γ基因的V-J连接序列。
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-02-01
S Dong, W Huang, J Tong, Z Wang, S Chen, Z Chen, L Gu, X Li, J Xie
{"title":"V-J junctional sequences of T cell receptor gamma gene in acute lymphocytic leukemia.","authors":"S Dong,&nbsp;W Huang,&nbsp;J Tong,&nbsp;Z Wang,&nbsp;S Chen,&nbsp;Z Chen,&nbsp;L Gu,&nbsp;X Li,&nbsp;J Xie","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>T cell receptor TCR gamma gene rearrangement in a series of acute lymphocytic leukemia (ALL) patients was studied using PCR technique. 18 V-J junctional sequences (designated by N sequence) of TCR gamma gene were amplified with the V gamma and J gamma primers, using an unsymmetrical PCR and analysed by direct sequencing, demonstrating that in Chinese ALLs, the N sequences of TCR gamma gene are indeed clone-specific. Based on the known N sequences, several oligo-nucleotides were synthesized as probes, which were specific for the leukemic clone, and were used to detect the minimal residual disease (MRD) in 4 ALL cases. The sensitivity of this method was 0.1%-0.01%.</p>","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"38 2","pages":"202-10"},"PeriodicalIF":0.0,"publicationDate":"1995-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18756651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
p10 genes of Bombyx mori nuclear polyhedrosis virus and Autographa californica multiple nuclear polyhedrosis virus. 家蚕核型多角体病毒和加州签名虫核型多角体病毒的p10基因。
Science in China. Series B, Chemistry, life sciences & earth sciences Pub Date : 1995-01-10 DOI: 10.1360/YB1995-38-1-50
Y. Zhang, X. Wu, Z. Li
{"title":"p10 genes of Bombyx mori nuclear polyhedrosis virus and Autographa californica multiple nuclear polyhedrosis virus.","authors":"Y. Zhang, X. Wu, Z. Li","doi":"10.1360/YB1995-38-1-50","DOIUrl":"https://doi.org/10.1360/YB1995-38-1-50","url":null,"abstract":"EcoR I-P fragment has been cloned from Autographa californica multiple nuclear polyhedrosis virus (AcMNPV) genomic DNA and used as a probe. 0.5-kb and 1.1-kb fragments including p10 gene from Bombyx mori nuclear polyhedrosis virus (BmNPV) have been hybridized. The p10 ORF was located in the EcoR I-R fragment. Initiation codon ATG of p10 from BmNPV has been mutated by PCR, and the ATG region became a Bgl II site. A novel transfer vector pBmAcPV-1 has been constructed using both the p10 5'-flanking region whose initiation codon ATG has been mutated with BmNPV and the p10 3'-flanking region of AcMNPV. The vector can recombine with not only AcMNPV DNA to express foreign gene in Sf cells, but also BmNPV DNA to express foreign gene in Bm cells. CAT gene was expressed at high level in Bm cells under the control of the mutated p10 promoter of BmNPV.","PeriodicalId":21648,"journal":{"name":"Science in China. Series B, Chemistry, life sciences & earth sciences","volume":"18 1","pages":"50-9"},"PeriodicalIF":0.0,"publicationDate":"1995-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81462067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
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