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1.
Naumov YN Naumova EN Yassai MB Gorski J 《Journal of immunology (Baltimore, Md. : 1950)》2011,186(11):6617-6624
The aging of T cell memory is often considered in terms of senescence, a process viewed as decay and loss of memory T cells. How senescence would affect memory is a function of the initial structure of the memory repertoire and whether the clonotypes that make up the repertoire decay at random. We examine this issue using the T cell memory generated to the conserved influenza A epitope M1(58-66), which induces a strong, focused, but polyclonal CD8 T cell response in HLA-A2 individuals. We analyzed the CD8 T cell memory repertoires in eight healthy middle-aged and eight healthy older blood donors representing an average age difference of ~ 27 y. Although the repertoires show broadly similar clonotype distributions, the number of observable clonotypes decreases significantly. This decrease disproportionally affects low-frequency clonotypes. Rank frequency analysis shows the same two-component clonotype distribution described earlier for these repertoires. The first component includes lower frequency clonotypes for which distribution can be described by a power law. The slope of this first component is significantly steeper in the older cohort. Generating a representative repertoire for each healthy cohort allowed agent-based modeling of the aging process. Interestingly, simple senescence of middle-aged repertoires is insufficient to describe the older clonotype distribution. Rather, a selective clonotype expansion must be included to achieve the best fit. We propose that responses to periodic virus exposure may drive such expansion, ensuring that the remaining clonotypes are optimized for continued protection. 相似文献
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Microsporidia is a large group of fungi-related unicellular eukaryotes with obligate intracellular lifestyle infecting a wide range of invertebrate and vertebrate hosts. Long adaptation of the parasites to intracellular development resulted in extraordinary minimization of their metabolic system. The paper summarizes the original results and literature data on the study of microsporidian carbohydrate and energy metabolism. On the basis of the material, it is concluded that minimization of microsporidian cell machinery was accompanied by the acquisition of a number of unique characteristics, which were not found in other eukaryotes. 相似文献
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A. V. Naumov 《Contemporary Problems of Ecology》2011,4(5):487-491
Peculiarities of forming emission flows of carbon dioxide and methane in forest-steppe raised Sphagnum bogs have been studied
in view of coenotic structure and damage to the vegetation as a result of fire. The reasons of relatively low rate of methane
emission in pine-dwarf shrub Sphagnum bogs under the marginal conditions have been analyzed. The concentrations of CH4 and CO2 in bog waters have been presented. 相似文献
6.
Kinetic and steady-state characteristics of sodium channels of the Ranvier node membrane, modified by aconitine, were investigated by the voltage clamp method. Channels modified by aconitine were shown to be only partially inactivated. Dependence of the fraction of uninactivated channels on voltage can be described by a model of a channel with three states: closed, open, and inactivated. It is suggested that aconitine does not significantly change the parameters of the inactivated state. Repolarization of the membrane to between –70 and –110 mV after a long (10 msec) test shift of potential induces initially a rapid decline of the current ("tail"), followed by a slow rise to the steady-state value. To explain the kinetics of this current it is necessary to postulate two or more open states of the channel.Institute of Cytology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 12, No. 6, pp. 612–618, November–December, 1980. 相似文献
7.
A comparative study of Lachancea kluyveri strains isolated in Europe, North America, Japan, and the Russian Far East was performed using restriction analysis, sequencing of non-coding rDNA regions, molecular karyotyping, and the phylogenetic analysis of the α-galactosidase MEL genes. This study showed a close genetic relatedness of these L. kluyveri strains. The chromosomal DNAs of the L. kluyveri strains were found to range in size from 980 to 3100 kb. The haploid number of chromosomes is equal to eight. The IGS2 restriction patterns and single nucleotide substitutions in the ITS1/ITS2 rDNA region correlate neither with geographic origin nor with the source of the strains. The L. kluyveri strains isolated from different sources have a high degree of homology (79–100%) of their MEL genes. The phylogenetic analysis of all of the known α-galactosidases in the “Saccharomyces” clade showed that the MEL genes of the yeasts L. kluyveri, L. cidri, Saccharomyces cerevisiae, S. paradoxus, S. bayanus, and S. mikatae are species specific. 相似文献
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LIN Yi;NIU Xuechun;ZHAO Qingpo;GU Xuejun;LI Xuan;LI Yongtao;HE Cunding;ZHAN Shijia;ZHANG Gaike;ZHU Zhiyong;ZHENG Lichao;SHI Jiazhen;LU Huayu;WANG Shejiang 《人类学学报》2022,41(03):481
During August 2019, Paleolithic archaeological survey was carried out in the Lushi Basin in the middle of South Luohe River, central China, 27 new Paleolithic open-air sites were identified and 123 lithic artifacts were collected. These sites are distributed on the first to fourth terrace of the South Luohe River, in situ lithic artifacts that buried in loess deposits have been found in some sites. 相似文献
10.
L. G. Marsagishvili M. D. Shpagina Yu. V. Shatalin V. S. Shubina A. A. Naumov M. M. Potselueva Z. A. Podlubnaya 《Biophysics》2006,51(5):705-709
Amyloid oligomers, protofibrils, and fibrils of various amyloidogenic proteins are known to induce cell death. Tetracycline prevents the formation of fibrils of Aβ peptide and other amyloidogenic proteins and decomposes mature fibrils. It was previously shown that sarcomeric cytoskeletal proteins of the titin family (protein X, protein C, and protein H) in vitro form amyloid fibrils and tetracycline decomposes them. In this work, the concentration and time dependence of the survival of polymorphonuclear leukocytes in the presence of protein X amyloid fibrils is demonstrated. It is also shown that the survival rate increases as fibrils are decomposed by tetracycline. The antibiotic itself is found to be nontoxic. The results obtained show that this approach can be used to evaluate the efficiency of drugs that prevent or rectify amyloidoses. 相似文献