排序方式: 共有33条查询结果,搜索用时 15 毫秒
1.
Molecular cloning of covalently closed circular DNA of bovine leukemia virus 总被引:2,自引:2,他引:0 下载免费PDF全文
The two species of covalently closed circular DNA molecules of bovine leukemia virus were cloned in the lambda phage vector lambda gtWES X lambda B. Of the nine independent recombinant lambda-bovine leukemia virus clones that were analyzed, three were derived from the small and six were derived from the large circular molecules carrying, respectively, one and two copies of the long terminal repeat sequences. Comprehensive restriction endonuclease mapping of the unintegrated bovine leukemia virus and the cloned DNA molecules showed that eight of the nine clones carried viral information without any detectable deletions or insertions of more than ca. 50 base pairs. One of the nine clones, which carries a retroviral insert with one copy of the long terminal repeat, had a deletion of ca. 150 base pairs. 相似文献
2.
3.
S. Quratulain B. Nasira M.A. Kashmiri 《World journal of microbiology & biotechnology》2006,22(3):213-218
Summary The penicillin G amidase (PGA) activity of a parent strain of E. coli (PCSIR-102) was enhanced by chemical mutagenization with N-methyl-N′-nitro-N-nitrosoguanidine (MNNG). After screening and optimization, a penicillinase deficient mutant (MNNG-37) was isolated and found
effective for the production of penicillin G amidase as compared to the parent strain of E. coli (PCSIR-102). Penicillin G amidase activity of MNNG-37 appeared during an early stage of growth, whereas PCSIR-102 did not
exhibit PGA activity due to the presence of penicillinase enzyme which inhibits the activity of enzyme PGA. However, MNNG-37
gave a three-fold increase in enzyme activity (231 IU mg−1) as compared to PCSIR-102 (77 IU mg−1) in medium containing 0.15 and 0.1% concentrations of phenylacetic acid, respectively which was added after 6 h of cultivation.
The difference in K
m values of the enzyme produced by parent strain PCSIR-102 (0.26 mM) and mutant strain MNNG-37 (0.20 mM) is significant (1.3-fold
increase in K
m value) which may show the superiority of the latter in terms of better enzyme properties. 相似文献
4.
A series of 1,4-disubstituted 1,2,3-bistriazoles was synthesized via click chemistry by cycloaddition of various bisalkynes with benzyl/2-phenylethyl azide. Synthesized triazoles were characterized by IR, (1)H NMR, (13)C NMR and mass spectral techniques. All the compounds were evaluated for antibacterial/antifungal activities and found to possess moderate to good antimicrobial activities. Further the docking study for the most active compound against DNA Gyrase was also carried out. 相似文献
5.
Md Aminul Islam Pratima Sinha Shyam Sundar Sharma Madan Singh Negi Bijoy Neog Shashi Bhushan Tripathi 《Plant Molecular Biology Reporter》2016,34(4):869-875
North eastern (NE) India harbours a precious germplasm repository of Capsicum in the form of various landraces. The present study was undertaken to characterise the extent of genetic variation present in different Capsicum landraces from north eastern India. A set of 171 Capsicum accessions were characterised using three-endonuclease amplified fragment length polymorphism (AFLP) markers. Out of 416 bands obtained from six primer combinations, 254 (61 %) were polymorphic. The pairwise genetic dissimilarity among accessions ranged from 0.03 to 0.97. Cluster analysis based on neighbour joining showed two major clusters. Cluster I contained most of the bhut jolokia accessions whereas cluster II contained all of the Capsicum annuum genotypes. Similar grouping was observed with population STRUCTURE analysis as well as principle coordinate analysis. Analysis of molecular variance (AMOVA) revealed 45 and 54 % variation among and within populations, respectively. This information on population structure analysis and molecular characterisation will be helpful for effective utilisation of this germplasm in Capsicum improvement programs. 相似文献
6.
Brijmohan Singh Bhau Kalyani Medhi Ambrish P. Das Siddhartha P. Saikia Kartik Neog S. N. Choudhury 《Biochemical genetics》2009,47(7-8):486-497
The utility of RAPD markers in assessing genetic diversity and phenetic relationships in Persea bombycina, a major tree species for golden silk (muga) production, was investigated using 48 genotypes from northeast India. Thirteen RAPD primer combinations generated 93 bands. On average, seven RAPD fragments were amplified per reaction. In a UPGMA phenetic dendrogram based on Jaccard’s coefficient, the P. bombycina accessions showed a high level of genetic variation, as indicated by genetic similarity. The grouping in the phenogram was highly consistent, as indicated by high values of cophenetic correlation and high bootstrap values at the key nodes. The accessions were scattered on a plot derived from principal correspondence analysis. The study concluded that the high level of genetic diversity in the P. bombycina accessions may be attributed to the species’ outcrossing nature. This study may be useful in identifying diverse genetic stocks of P. bombycina, which may then be conserved on a priority basis. 相似文献
7.
8.
Detection, purification, and characterization of two species of covalently closed circular proviral DNA molecules of bovine leukemia virus 总被引:1,自引:1,他引:0 下载免费PDF全文
Cocultivation of uninfected and bovine leukemia virus-producing bat cells yielded, in addition to the unintegrated linear DNA duplex, DNA molecules that migrated as 4.4- and 4.8-kilobase-pair DNA fragments in gel electrophoresis. These DNA molecules were purified by acid-phenol extraction and cleaved with restriction endonucleases EcoRI, and HindIII, which have one recognition site each on the bovine leukemia virus proviral DNA. Such cleavage generated DNA molecules of approximately 10.0 and 9.4 kilobase pairs, thus indicating the existence of two species of covalently closed circular molecules of bovine leukemia virus proviral DNA. 相似文献
9.
De Pascalis R Iwahashi M Tamura M Padlan EA Gonzales NR Santos AD Giuliano M Schuck P Schlom J Kashmiri SV 《Journal of immunology (Baltimore, Md. : 1950)》2002,169(6):3076-3084
Murine mAb COL-1 reacts with carcinoembryonic Ag (CEA), expressed on a wide range of human carcinomas. In preclinical studies in animals and clinical trials in patients, murine COL-1 showed excellent tumor localization. To circumvent the problem of immunogenicity of the murine Ab in patients, a humanized COL-1 (HuCOL-1) was generated by grafting the complementarity-determining regions (CDRs) of COL-1 onto the frameworks of the variable light and variable heavy regions of human mAbs. To minimize anti-V region responses, a variant of HuCOL-1 was generated by grafting onto the human frameworks only the "abbreviated" CDRs, the stretches of CDR residues that contain the specificity-determining residues that are essential for the surface complementarity of the Ab and its ligand. In competition RIAs, the recombinant variant completely inhibited the binding of radiolabeled murine and humanized COL-1 to CEA. The HuCOL-1 and its variant showed no difference in their binding ability to the CEA expressed on the surface of a CEA-transduced tumor cell line. Compared with HuCOL-1, the HuCOL-1 variant showed lower reactivity to patients' sera carrying anti-V region Abs to COL-1. The final variant of the HuCOL-1, which retains its Ag-binding reactivity and shows significantly lower serum reactivity than that of the parental Ab, can serve as a prototype for the development of a potentially useful clinical reagent. 相似文献
10.
Sharma N. Chakraborty M. Borthakur S. Neog N. K. Bandyopadhyay M. 《Plasma Physics Reports》2022,48(4):395-407
Plasma Physics Reports - The study of power absorption in a helicon plasma source excited by 13.56 MHz frequency is reported. Numerical analysis is carried out to determine the power absorption in... 相似文献