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991.
Joshua D. Doyle Jennifer E. Stencel-Baerenwald Courtney A. Copeland Jillian P. Rhoads Judy J. Brown Kelli L. Boyd James B. Atkinson Terence S. Dermody 《PLoS pathogens》2015,11(3)
Reovirus is a nonenveloped mammalian virus that provides a useful model system for studies of viral infections in the young. Following internalization into host cells, the outermost capsid of reovirus virions is removed by endosomal cathepsin proteases. Determinants of capsid disassembly kinetics reside in the viral σ3 protein. However, the contribution of capsid stability to reovirus-induced disease is unknown. In this study, we found that mice inoculated intramuscularly with a serotype 3 reovirus containing σ3-Y354H, a mutation that reduces viral capsid stability, succumbed at a higher rate than those infected with wild-type virus. At early times after inoculation, σ3-Y354H virus reached higher titers than wild-type virus at several sites within the host. Animals inoculated perorally with a serotype 1 reassortant reovirus containing σ3-Y354H developed exaggerated myocarditis accompanied by elaboration of pro-inflammatory cytokines. Surprisingly, unchallenged littermates of mice infected with σ3-Y354H virus displayed higher titers in the intestine, heart, and brain than littermates of mice inoculated with wild-type virus. Together, these findings suggest that diminished capsid stability enhances reovirus replication, dissemination, lethality, and host-to-host spread, establishing a new virulence determinant for nonenveloped viruses. 相似文献
992.
HPLC photofingerprinting of conformational peculiarities and transitions in oligonucleotide duplexes. 下载免费PDF全文
Two self-complementary sequence-isomeric decadeoxyribonucleotides were exposed to UV light under conditions in which they assume duplex structures. After that they were analyzed in the denatured state by reversed-phase high-performance liquid chromatography (HPLC). Characterization of the separated photoproducts allowed localization of cyclobutane pyrimidine dimers in the sequences of the modified oligonucleotides. For [d(GGAAATTTCC)]2, which is known to contain in its central part a stretch of rigid B'-conformation with decreased mobility of constituent bases, lower yields of thymine dimers, as compared with that for ordinary B-form [d(CCTTTAAAGG)]2, were found. On the contrary, mixed thymine-cytosine heterodimers generated in the former oligonucleotide demonstrate the increase in photoreactivity of these residues at the B'-B junction. This is probably due to the peculiar conformation adopted by this decanucleotide. Stimulation of B'-B transition, by increasing the temperature before melting, reduced an inhibition of thymine photodimer formation. During the melting of both oligonucleotides yields of all identified photoinduced cyclobutadipyrimidines were reduced. Possible influences of some metal cations on the stability of the B'-form were also studied by this photoprobing technique. The present study demonstrates the feasibility of HPLC photofingerprinting as a new approach for structural analysis of nucleic acids. 相似文献
993.
The RAD6 gene of Saccharomyces cerevisiae, which encodes a ubiquitin-conjugating enzyme, is required for DNA repair, DNA damage-induced mutagenesis and sporulation. To evaluate the biological relevance of the thioester adduct between RAD6 protein and ubiquitin, formed as an obligatory, transient intermediate during ubiquitin conjugation to substrates, we altered cysteine 88 in RAD6 to serine. Esterification with ubiquitin occurs at serine 88 in the mutant protein, but conjugation of ubiquitin to the test substrate histone H2A is inactivated. Phenotypically, strains harboring the rad6 Ser88 allele are indistinguishable from rad6 deletion (rad6 delta) mutant cells. These findings argue against ligation of ubiquitin at cysteine 88 acting as a functional switch of a cryptic biochemical activity in RAD6. 相似文献
994.
How many signals are enough? 总被引:1,自引:0,他引:1
N R Sinclair 《Cellular immunology》1990,130(1):204-12; discussion 213-35
The many signals that control the progress of various immune responses to both foreign and self antigens can be divided into no less than three major groups. The first group is the initial positive stimulus, associated with activation events through antigen receptors and their associated proteins. These signals launch lymphocytes in their response to antigen, either foreign or self. The second group of signals is negative and involves various end products and interactions between cells, all recognizing antigen. These signals are endogenous to the reacting cell, or nearly so (two interacting cells from the same clone, daughter cells, which are in the same locale and bind to the same ligand). The third group (the prevention of end product feedback, involving various forms of antigen presentation, T cell contributions, rheumatoid factor activity, and other mechanisms) is more likely to occur with nonself antigens, which are temporally and spatially more restricted than self antigens. Experimental evidence for this immunological schema is summarized and clarified in its relationship to the Bretscher-Cohn theory of self-nonself recognition and to suppressor cell and idiotype-antiidiotypic theories. 相似文献
995.
Reuben S.E. Young Andrew P. Bowman Kaylyn D. Tousignant Berwyck L.J. Poad Jennifer H. Gunter Lisa K. Philp Colleen C. Nelson Shane R. Ellis Ron M.A. Heeren Martin C. Sadowski Stephen J. Blanksby 《Journal of lipid research》2022,63(6):100223
The cellular energy and biomass demands of cancer drive a complex dynamic between uptake of extracellular FAs and their de novo synthesis. Given that oxidation of de novo synthesized FAs for energy would result in net-energy loss, there is an implication that FAs from these two sources must have distinct metabolic fates; however, hitherto, all FAs have been considered part of a common pool. To probe potential metabolic partitioning of cellular FAs, cancer cells were supplemented with stable isotope-labeled FAs. Structural analysis of the resulting glycerophospholipids revealed that labeled FAs from uptake were largely incorporated to canonical (sn-) positions on the glycerol backbone. Surprisingly, labeled FA uptake also disrupted canonical isomer patterns of the unlabeled lipidome and induced repartitioning of n-3 and n-6 PUFAs into glycerophospholipid classes. These structural changes support the existence of differences in the metabolic fates of FAs derived from uptake or de novo sources and demonstrate unique signaling and remodeling behaviors usually hidden from conventional lipidomics. 相似文献
996.
997.
I. N. Konareva 《Neurophysiology》2006,38(3):201-208
Modifications of different EEG rhythms induced by a single neurofeedback session (by the EEG characteristics) directed toward
an increase in the ratio of the spectral powers (SPs) of the α vs θ oscillations were compared with the psychological characteristics of the tested subjects (the group included 30 persons).
A generally accepted neurofeedback technique was used; the intensity of acoustic white noise served as the feedback signal.
EEG potentials were recorded from the C3 and C4 leads. Psychological testing was carried out using Eysenck’s (EPQ), Rusalov’s
(OST), and (16 PF) questionnaires. The directions of changes in the SPs of EEG frequency components were found to significantly
correlate with some individuality-related peculiarities of the tested subjects. The SP of the δ rhythm correlated with the
EPQ scale “neuroticism,” OST scale “social plasticity,” and 16 PF factors H (“parmia”), I (“premsia”), and Q3 (“self-control of behavior”). The SP of the θ component demonstrated correlations with the OST scales “ergisity,” “plasticity,”
and “social temp” and with 16 PF factors M (“autia”), Q4 (“frustration”), and Q1 (“exvia”). The SP of the α rhythm correlated with 16 PF factors Q3 (“self-control of behavior”), G (“strength of superEgo”), O (“hypothymia”), L (“protension”), and N (“shrewdness”). The SP
of the β rhythm correlated with the OST scale “emotionality,” while that of the γ rhythm showed correlations with the 16 PF
indices L (“protension”) and M (“autia”). Changes in the ratio of the α vs θ SPs correlated with the EPQ scale “neuroticism.” Thus, our data confirm the statement that a high individual variability
of the results of a single (first in the series) neurofeedback session is to a great extent related to peculiarities of the
individual psychological pattern of the subject.
Neirofiziologiya/Neurophysiology, Vol. 38, No. 3, pp. 239–247, May–June, 2006. 相似文献
998.
Immersion staining of coarse fish in the Thames 总被引:1,自引:0,他引:1
C. P. Mathews 《Journal of fish biology》1970,2(1):57-58
Thirty-one vital dyes were screened for marking bleak, roach and gudgeon by total body immersion in aqueous solutions of the dye. Only six dyes stained without killing, and of these Nile blue, neutral red and Bismarck brown were used successfully in the field. This approach to estimation of population size was abandoned because (1) the toxicity of the dyes varied at different times of year, (2) the numbers needed for release were impractically high and (3) fingerlings showed extremely high mortality on handling. 相似文献
999.
A study was made of the dose-time relationship during chromatin degradation in white blood cells of non-irradiated and irradiated rats. There was a linear increase in the release of PDN from leukocytes 1,2 and 3 days after irradiation (1-3 Gy) followed by the deceleration of the chromatin degradation at doses exceeding 3 Gy. 相似文献
1000.