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1.
A plasmid containing inverted repeats is constructed in Bacillus subtilis. Insertion of DNA fragments into the plasmid inverted repeats results either in the precise excision of the insert or in its duplication in the opposite inverted repeat. These rearrangements are due to the presence of inverted repeats only. Two recombination events are possibly responsible for these phenomena. During the first step of the recombination two plasmid monomers form a dimer molecule. During the second step the intramolecular recombination between the direct repeats in the dimer structure leads to the formation of two rearranged plasmid monomers devoid of insertion or containing two DNA inserts. Proposed dimeric intermediate is unstable in B. subtilis. However, it is isolated from Escherichia coli recA, cells. Plasmids containing the inverted repeats can serve as a model to study plasmid recombination in B. subtilis cells. 相似文献
2.
V V Iurovski? N G Safonova S V Kha?dukov R G Vasilov V V Demin 《Bioorganicheskaia khimiia》1986,12(1):89-99
Primary structure of murine class I histocompatibility antigens has been analysed to select possible antigenic determinant. Hexapeptide Leu-Gln-Gln-Leu-Ser-Gly, homologous to the region 95-100 of the H-2Db antigen heavy chain, was synthesised by stepwise elongation of peptide chain beginning from the COOH-terminal Gly. Rabbit anti-hexapeptide antibodies were obtained and shown to interact specifically with purified H-2Db antigen as well as with the native antigen on cell surface. These antibodies bind to lymphocytes of H-2b haplotype (C57BL/6 mice) but not H-2d (BALB/c) or H-2k (CBA). These data suggest that the region 95-100 is responsible for serologic differences between the alleles of H-2 antigens, i.e. it may be a xenotypic as well as an allotypic antigenic determinant. The latter was confirmed by study of interaction of the hexapeptide with allogeneic monoclonal antibodies specific to H-2Db antigen. 相似文献
3.
4.
N V Kha?darova G N Rudenskaia V M Stepanov N S Egorob 《Prikladnaia biokhimiia i mikrobiologiia》1991,27(3):375-380
The secretion of some proteolytic enzymes by Streptomyces thermovulgaris T 54 was studied using artificial chromogenic substrates of proteinases. Maximum accumulation of the enzymes hydrolysing Z-Glu-pNA and Z-Ala-Ala-Leu-pNA occurred during autolysis of the culture. Two peaks of activity were observed, when DNP-Gly-Gly-Ile-Arg was used as a substrate, one of them being correspondent to prevalence of dense colonies in the culture and the other to the prevalence of friable networks of hyphae. 相似文献
5.
Salicylic acid is an important signalling molecule involved in both locally and systemically induced disease resistance responses. Recent advances in our understanding of plant defence signalling have revealed that plants employ a network of signal transduction pathways, some of which are independent of salicylic acid. Evidence is emerging that jasmonic acid and ethylene play key roles in these salicylic acid-independent pathways. Cross-talk between the salicylic acid-dependent and the salicylic acid-independent pathways provides great regulatory potential for activating multiple resistance mechanisms in varying combinations. 相似文献
6.
Veselov SIu Khaĭbullina SF Morzunov SP Khasanova SS Li LE Garipova ME Klimchuk LA Speranskiĭ VV Kulagin VF Magazov RSh 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》2003,(1):55-59
Pumala virus recombinant nucleocapsid protein was used for the early diagnosis of haemorrhagic fever with renal syndrome. Specific IgM in the sera of patients could be determined by the IEA technique as early as on days 2-3 from the onset of the disease. The diagnostic effectiveness of the test-system was 95% and its specificity was 98%. 相似文献
7.
The differential sensitivity of peripheral blood (PB) CD4+ T lymphocytes to the calcium ionophore ionomycin was investigated. Effect of ionomycin exerted on T cells was time- and dose-dependent. We have shown that resistant cells belonged to some distinct T cell subsets. The resting naive CD4+CD45RA+ T cells showed a little, if any, resistance to ionomycin treatment. The primed CD4+CD45R0+ memory T cells behaved similarly as did ionomycin-resistant (IR) cells. Although IR CD4+ T cells had a typical "memory" phenotype, some quantitative differences were found in expression of CD11a, CD28, CD29, CD62L and CD243 markers between PB CD4+CD45R0+ T cells and corresponding IR cells. 相似文献
8.
AB Chang NC Cox J Purcell JM Marchant PJ Lewindon GJ Cleghorn LC Ee GD Withers MK Patrick J Faoagali 《Respiratory research》2005,6(1):1-5
Background and methods
Human metapneumovirus (hMPV) is a recently discovered respiratory virus associated with bronchiolitis, pneumonia, croup and exacerbations of asthma. Since respiratory viruses are frequently detected in patients with acute exacerbations of COPD (AE-COPD) it was our aim to investigate the frequency of hMPV detection in a prospective cohort of hospitalized patients with AE-COPD compared to patients with stable COPD and to smokers without by means of quantitative real-time RT-PCR.Results
We analysed nasal lavage and induced sputum of 130 patients with AE-COPD, 65 patients with stable COPD and 34 smokers without COPD. HMPV was detected in 3/130 (2.3%) AE-COPD patients with a mean of 6.5 × 105 viral copies/ml in nasal lavage and 1.88 × 105 viral copies/ml in induced sputum. It was not found in patients with stable COPD or smokers without COPD.Conclusion
HMPV is only found in a very small number of patients with AE-COPD. However it should be considered as a further possible viral trigger of AE-COPD because asymptomatic carriage is unlikely. 相似文献9.
Chintamani Pranjal Kulshreshtha Anurupa Chakraborty LC Singh Ashwani K Mishra Dinesh Bhatnagar Sunita Saxena 《World journal of surgical oncology》2010,8(1):1-9
Voltage gated potassium channels have been extensively studied in relation to cancer. In this review, we will focus on the role of two potassium channels, Ether à-go-go (Eag), Human ether à-go-go related gene (HERG), in cancer and their potential therapeutic utility in the treatment of cancer. Eag and HERG are expressed in cancers of various organs and have been implicated in cell cycle progression and proliferation of cancer cells. Inhibition of these channels has been shown to reduce proliferation both in vitro and vivo studies identifying potassium channel modulators as putative inhibitors of tumour progression. Eag channels in view of their restricted expression in normal tissue may emerge as novel tumour biomarkers. 相似文献
10.
B M Kurinenko E V Sergeeva L I Sobchuk R Sh Bulgakova S A Kha?bullina 《Antibiotiki i khimioterapii͡a》1989,34(4):266-270
Cytotoxicity of RNAase from Bacillus intermedius was studied in vitro and in vivo. It was shown that the enzyme had slightly pronounced cytotoxicity according to the tests with inhibition of cell proliferation and biosynthesis of cell nucleic acids. The RNAase was also shown to impair the vital staining by neutral red. The efficiency of the impairment much more depended on the enzyme catalytic activity than on the proliferation and biosynthesis of nucleic acids. In vivo toxicity of RNAase from B. intermedius was 3-5 times higher than that of pancreatic RNAase. Possible mechanisms of the different toxicity of the enzymes are discussed. 相似文献