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One hundred and eight vaccine-derived strains of types 1, 2, and 3 poliovirus (25 PV1, 34 PV2, and 48 PV3) isolated in Belarus in 1960-1999 were analyzed by double restriction fragment length polymorphism assay (RFLP-1, -3D1). Forty-four (40.7%) of strains were genetically modified. Eight (7.4%) PV were modified by mutation, 16 (14.8%) by recombination, and 20 (18.5%) by both mutation and recombination. The genomes of 16 PV were analyzed by multiple RFLP technique covering VP1-, VP1/VP2A-, P2-, 3AC-, and 3D1-coding regions. The majority of recombinants were "simple" (with one crossing over site). One strain was "double" recombinant (two crossings over sites) and one more "multiple" recombinant (three crossing over sites). Partial nucleotide sequencing of some recombinant strains showed that the degree of these strains' divergence was less than 1% in comparison with the original vaccine viruses.  相似文献   

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<正>Following a short struggle against an aggressive cancer,Prof.Jure Piskur(Fig.1),a professor of molecular genetics at Lund University(LU),Sweden,and the University of Nova Gorica(UNG),Slovenia,died in his home in Lund on 18 May 2014.He leaves behind his lifelong partner and wife,Judita Gartner,and their sons,Jan and Jure.Jure Piskur was born in 1960 in Slovenia,at that time part of Yugoslavia.Even when Jure’s research led him to many countries and the last quarter of a century to Scandinavia,he always kept close contact with his home country.He was proud to have participated in the Slovenian independence movement,which led to its international recognition as a sovereign state in  相似文献   

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This is an historical paper examining the scientific background of George Ledyard Stebbins, Jr. (b. 1906), one of the foremost botanists of this century and one of the architects of the evolutionary synthesis, the intellectual event that brought together genetics and selection theory in the interval between 1920 and 1950. It considers his scientific influence and research, beginning with his Harvard education in 1924 and ending in 1950 with the publication of his book Variation and Evolution in Plants. The paper also more broadly assesses the contributions of other botanists to the evolutionary synthesis, including discussion of the work of Edgar Anderson (1897-1967) and others. It also traces the larger historical patterns of American botany, which saw a shift from East Coast botany as exemplified by Harvard botany, to West Coast botany, as exemplified by California botany.  相似文献   

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Antibody responses of Macaca fascicularis against a new tetravalent vaccine composed of diphtheria toxoid, tetanus toxoid, acellular pertussis antigens, and inactivated poliovirus derived from Sabin strains (sIPV) was investigated to predict an optimal dose of sIPV in a new tetravalent vaccine (DTaP-sIPV) prior to conducting a dose-defined clinical study. Monkeys were inoculated with DTaP-sIPVs containing three different antigen units of sIPVs: Vaccine A (types 1:2:3 = 3:100:100 DU), Vaccine B (types 1:2:3 = 1.5:50:50 DU), and Vaccine C (types 1:2:3 = 0.75:25:25 DU). There was no difference in the average titers of neutralizing antibody against the attenuated or virulent polioviruses between Vaccines A and B. The average neutralizing antibody titers of Vaccine C tended to be lower than those of Vaccines A and B. The sIPV antigens did not affect the anti-diphtheria or anti-tetanus antibody titers of DTaP-sIPV. Furthermore, the average neutralizing antibody titers of Vaccine A against the attenuated and virulent polioviruses were comparable between M. fascicularis and humans. These results suggest that M. fascicularis may be a useful animal model for predicting the antibody responses to sIPVs in humans, and that it may be likely to reduce the amount of sIPVs contained in DTaP-sIPVs, even for humans.  相似文献   

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This study assessed the relationship between radon decay product (RDP) exposure and mortality and cancer incidence in a cohort of 17,660 Eldorado uranium workers first employed in 1932-1980 and followed up through 1999. The analysis was based on substantially revised identifying information and dosimetry for workers from the Beaverlodge and Port Radium uranium mines and for the first time includes workers from a radium and uranium refinery and processing facility in Port Hope, Canada. Overall, male workers had lower mortality rates of all causes and all cancers and lower incidence rates of all cancers compared with the general Canadian male population, a likely healthy worker effect. Individual cancer rates were also reduced except for lung cancer mortality (SMR = 1.31, P < 0.001) and incidence (SIR = 1.23, P < 0.001). The excess relative risk per 100 WLM (ERR/100 WLM) of lung cancer mortality (N = 618, ERR/100 WLM = 0.55, 95% CI: 0.37, 0.78, P < 0.01) and incidence (N = 626, ERR/100 WLM = 0.55, 95% CI: 0.37, 0.81, P < 0.001) increased linearly with increasing RDP exposure. Adjustment for effect modification by time since exposure, exposure rate and age at risk resulted in comparable estimates of risk of lung cancer for all three uranium worksites. RDP exposures and γ-ray doses were not associated with any other cancer site or other cause of death. The risk estimates are in agreement with the results of the pooled analysis of 11 miner cohorts and more recent studies of uranium workers. The current analysis provides more precise risk estimates and compares the findings from the mortality study with the incidence study. Future follow-up of the cohort and joint analysis with other uranium miners' studies should shed more light on the effects of low RDP exposures as experienced by current workers as well as help to understand and address the health risks associated with residential radon.  相似文献   

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<正>It is with profound sadness that we mourn the loss of Dr.Biao Ding,a full-professor in the Department of Molecular Genetics,Ohio State University(OSU),and a world-renowned plant biologist with leading authority in viroid research.He died suddenly on June 26,2015 in Prague,Czech Republic,while attending the International Conference on Viroids and Viroid-Like RNAs as a Keynote Speaker.Dr.Ding was born in 1960,in Kunming,Yunnan Province,China.He received his B.S.from Beijing Forestry University in1982,and was then selected as one of the first group of  相似文献   

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Heating the Sabin strains of poliovirus at 42 to 45 degrees C caused inactivation, loss of native antigen, and release of the viral RNA (vRNA). The loss of virion infectivity exceeded the loss of vRNA infectivity (as measured by transfection) by roughly 2 log10. Pirodavir inhibited the loss of native antigen and RNA release and reduced the loss of virion infectivity to the same level as the loss of vRNA infectivity. Thermoinactivation thus involves an RNA and a protein component, and pirodavir protected only against the latter.  相似文献   

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Ohne Zusammenfassung  相似文献   

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The catalytic mechanism of phosphoenolpyruvate (PEP) carboxylase from Zea mays has been studied using (Z)- and (E)-3-fluorophosphoenolpyruvate (F-PEP) as substrates. Both (Z)- and (E)-F-PEP partition between carboxylation to produce 3-fluorooxalacetate and hydrolysis to produce 3-fluoropyruvate. Carboxylation accounts for 3% of the reaction observed with (Z)-F-PEP, resulting in the formation of (R)-3-fluorooxalacetate, and for 86% of the reaction of (E)-F-PEP forming (S)-3-fluorooxalacetate. Carboxylation of F-PEP occurs on the 2-re face, which corresponds to the 2-si face of PEP. The partitioning of F-PEP between carboxylation and hydrolysis is insensitive to pH but varies with metal ion. Use of 18O-labeled bicarbonate produces phosphate that is multiply labeled with 18O; in addition, 18O is also incorporated into residual (Z)- and (E)-F-PEP. The 13(V/K) isotope effect on the carboxylation of F-PEP catalyzed by PEP carboxylase at pH 8.0, 25 degrees C, is 1.049 +/- 0.003 for (Z)-F-PEP and 1.009 +/- 0.006 for (E)-F-PEP. These results are consistent with a mechanism in which carboxylation of PEP occurs via attack of the enolate of pyruvate on CO2 rather than carboxy phosphate. In this mechanism phosphorylation of bicarbonate to give carboxy phosphate and decarboxylation of the latter are reversible steps. An irreversible step, however, precedes partitioning between carboxylation to give oxalacetate and release of CO2, which results in hydrolysis of PEP.  相似文献   

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A review of the 637 out of a total of 941 consecutive cases of acute poisoning admitted to an acute medical unit without special facilities for the treatment of poisoning has shown that despite considerable limitations in the medical, nursing, and laboratory facilities available the results compare favourably with those reported from specialized units.  相似文献   

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