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71.
Irina V. Pisareva Igot T. Chizhevsky Pavel V. Petrovskii Eugenii V. Vorontzov Vladimir I. Bregadze Fedor M. Dolgushin Aleksandr I. Yanovsky 《Inorganica chimica acta》1998,280(1-2):233-237
The first η2-olefinic monocarbon metallacarbone closo-2-(Ph3P)-1-N,2-[μ-(η2-CH2CH=Ch2)]-1-N-(σ-CH2CH=CH2)-2,1- RhCB10H10 has been prepared by the reaction of the dimeric anion {[Ph3PRhB10H10CNH2]2-μ-H}−[PPN]+ with allyl bromide and characterized by a combination of spectroscopic methods and a single-crystal X-ray diffraction study. The variable temperature 1H and 13C NMR studies revealed the fluxional behavior of the η2-olefinic complex in CD2Cl2 solution which is associated with the allyl side-chain exchange process. 相似文献
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Altschul SF Wootton JC Gertz EM Agarwala R Morgulis A Schäffer AA Yu YK 《The FEBS journal》2005,272(20):5101-5109
Almost all protein database search methods use amino acid substitution matrices for scoring, optimizing, and assessing the statistical significance of sequence alignments. Much care and effort has therefore gone into constructing substitution matrices, and the quality of search results can depend strongly upon the choice of the proper matrix. A long-standing problem has been the comparison of sequences with biased amino acid compositions, for which standard substitution matrices are not optimal. To address this problem, we have recently developed a general procedure for transforming a standard matrix into one appropriate for the comparison of two sequences with arbitrary, and possibly differing compositions. Such adjusted matrices yield, on average, improved alignments and alignment scores when applied to the comparison of proteins with markedly biased compositions. Here we review the application of compositionally adjusted matrices and consider whether they may also be applied fruitfully to general purpose protein sequence database searches, in which related sequence pairs do not necessarily have strong compositional biases. Although it is not advisable to apply compositional adjustment indiscriminately, we describe several simple criteria under which invoking such adjustment is on average beneficial. In a typical database search, at least one of these criteria is satisfied by over half the related sequence pairs. Compositional substitution matrix adjustment is now available in NCBI's protein-protein version of blast. 相似文献
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Lipatov AS Govorkova EA Webby RJ Ozaki H Peiris M Guan Y Poon L Webster RG 《Journal of virology》2004,78(17):8951-8959
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Trutko SM Akimenko VK Suzina NE Anisimova LA Shlyapnikov MG Baskunov BP Duda VI Boronin AM 《Archives of microbiology》2000,173(3):178-186
The terminal oxidases of the respiratory chain of seven strains of gram-negative bacteria were shown to be involved in the reduction of tellurite. The rate of tellurite reduction correlated with the intensity of respiration. The inhibitors of terminal oxidases, carbon monoxide and cyanide, inhibited the reduction of tellurite. In Pseudomonas aeruginosa PAO ML4262 and P. aeruginosa PAO ML4262 (pBS 10), the respiratory chain was found to contain three types of cytochrome c, one of which (the carbon monoxide-binding cytochrome c) was involved in the reduction of tellurite. Agrobacterium tumefaciens VKM B-1219, P. aeruginosa IBPM B-13, and Escherichia coli G0-102bd++ cells contained oxidases aa3, bb3, and bd, respectively. The respiratory chain of other strains contained two oxidases: E. coli DH5alpha of bb3- and bd-type, and Erwinia carotovora VKM B-567 of bo3- and bd-type. All the strains under study reduced tellurite with the formation of tellurium crystallites. Depending on the position of the active center of terminal oxidases in the plasma membrane, the crystallites appeared either in the periplasmic space [P. aeruginosa PAO ML4262 and P. aeruginosa PAO ML4262 (pBS10)], or on the outer surface of the membrane (A. tumefaciens VKM B-1219 and P. aeruginosa IBPM B-13), its inner surface (E. coli G0-102bd++), or on both surfaces (E. coli DHaalpha and E. carotovora VKM B-567). 相似文献
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Rovner A Greenberg NL Thomas JD Garcia MJ 《American journal of physiology. Heart and circulatory physiology》2005,289(5):H2081-H2088
We sought to elucidate the relationship between diastolic intraventricular pressure gradients (IVPG) and exercise tolerance in patients with heart failure using color M-mode Doppler. Diastolic dysfunction has been implicated as a cause of low aerobic potential in patients with heart failure. We previously validated a novel method to evaluate diastolic function that involves noninvasive measurement of IVPG using color M-mode Doppler data. Thirty-one patients with heart failure and 15 normal subjects were recruited. Echocardiograms were performed before and after metabolic treadmill stress testing. Color M-mode Doppler was used to determine the diastolic propagation velocity (Vp) and IVPG off-line. Resting diastolic function indexes including myocardial relaxation velocity, Vp, and E/Vp correlated well with VO2max (r = 0.8, 0.5, and -0.5, respectively, P < 0.001 for all). There was a statistically significant increase in Vp and IVPG in both groups after exercise, but the change in IVPG was higher in normal subjects compared with patients with heart failure (2.6 +/- 0.8 vs. 1.1 +/- 0.8 mmHg, P < 0.05). Increase in IVPG correlated with peak VO2max (r = 0.8, P < 0.001) and was the strongest predictor of exercise capacity. Myocardial relaxation is an important determinant of exercise aerobic capacity. In heart failure patients, impaired myocardial relaxation is associated with reduced diastolic suction force during exercise. 相似文献
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Transmissible self-assembled fibrous cross-β polymer infectious proteins (prions) cause neurodegenerative diseases in mammals and control non-Mendelian heritable traits in yeast. Cross-species prion transmission is frequently impaired, due to sequence differences in prion-forming proteins. Recent studies of prion species barrier on the model of closely related yeast species show that colocalization of divergent proteins is not sufficient for the cross-species prion transmission, and that an identity of specific amino acid sequences and a type of prion conformational variant (strain) play a major role in the control of transmission specificity. In contrast, chemical compounds primarily influence transmission specificity via favoring certain strain conformations, while the species origin of the host cell has only a relatively minor input. Strain alterations may occur during cross-species prion conversion in some combinations. The model is discussed which suggests that different recipient proteins can acquire different spectra of prion strain conformations, which could be either compatible or incompatible with a particular donor strain. 相似文献
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Sharath P. Sasi Sanggyu Bae Jin Song Aleksandr Perepletchikov Douglas Schneider Joseph Carrozza Xinhua Yan Raj Kishore Heiko Enderling David A. Goukassian 《PloS one》2014,9(3)
Tumor necrosis factor-alpha (TNF) binds to two receptors: TNFR1/p55-cytotoxic and TNFR2/p75-pro-survival. We have shown that tumor growth in p75 knockout (KO) mice was decreased more than 2-fold in Lewis lung carcinoma (LLCs). We hypothesized that selective blocking of TNFR2/p75 LLCs may sensitize them to TNF-induced apoptosis and affect the tumor growth. We implanted intact and p75 knockdown (KD)-LLCs (>90%, using shRNA) into wild type (WT) mice flanks. On day 8 post-inoculation, recombinant murine (rm) TNF-α (12.5 ng/gr of body weight) or saline was injected twice daily for 6 days. Tumor volumes (tV) were measured daily and tumor weights (tW) on day 15, when study was terminated due to large tumors in LLC+TNF group. Tubular bones, spleens and peripheral blood (PB) were examined to determine possible TNF toxicity. There was no significant difference in tV or tW between LLC minus (-) TNF and p75KD/LLC-TNF tumors. Compared to 3 control groups, p75KD/LLC+TNF showed >2-5-fold decreases in tV (p<0.001) and tW (p<0.0001). There was no difference in tV or tW end of study vs. before injections in p75KD/LLC+TNF group. In 3 other groups tV and tW were increased 2.7-4.5-fold (p<0.01, p<0.0002 and p<0.0001). Pathological examination revealed that 1/3 of p75KD/LLC+rmTNF tumors were 100% necrotic, the remaining revealed 40-60% necrosis. No toxicity was detected in bone marrow, spleen and peripheral blood. We concluded that blocking TNFR2/p75 in LLCs combined with intra-tumoral rmTNF injections inhibit LLC tumor growth. This could represent a novel and effective therapy against lung neoplasms and a new paradigm in cancer therapeutics. 相似文献
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Alessia Galgano Aleksandr Barinov Florence Vasseur Jean-Pierre de Villartay Benedita Rocha 《PloS one》2015,10(10)
Immune responses are efficient because the rare antigen-specific naïve cells are able to proliferate extensively and accumulate upon antigen stimulation. Moreover, differentiation into memory cells actually increases T cell accumulation, indicating improved productive division in secondary immune responses. These properties raise an important paradox: how T cells may survive the DNA lesions necessarily induced during their extensive division without undergoing transformation. We here present the first data addressing the DNA damage responses (DDRs) of CD8 T cells in vivo during exponential expansion in primary and secondary responses in mice. We show that during exponential division CD8 T cells engage unique DDRs, which are not present in other exponentially dividing cells, in T lymphocytes after UV or X irradiation or in non-metastatic tumor cells. While in other cell types a single DDR pathway is affected, all DDR pathways and cell cycle checkpoints are affected in dividing CD8 T cells. All DDR pathways collapse in secondary responses in the absence of CD4 help. CD8 T cells are driven to compulsive suicidal divisions preventing the propagation of DNA lesions. In contrast, in the presence of CD4 help all the DDR pathways are up regulated, resembling those present in metastatic tumors. However, this up regulation is present only during the expansion phase; i.e., their dependence on antigen stimulation prevents CD8 transformation. These results explain how CD8 T cells maintain genome integrity in spite of their extensive division, and highlight the fundamental role of DDRs in the efficiency of CD8 immune responses. 相似文献