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61.
E A Moskvitina L S Podosinnikova E M Kvasov R A Brudny? E V Monakhova A A Levkovich V D Serdiukova L P Kokoeva L V Nevenchannaia M D Kapustina 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1990,(8):62-66
The analysis of the data on the isolation of V. cholerae from different ecological systems indicates that V. eltor do not constantly inhibit the rivers and sea at the territory under control. Hemolytically active V. cholerae without the vct gene, found to be faintly virulent and avirulent when studied on suckling rabbits used as a model and when evaluated by the complex method, show no tendency towards epidemic spread in the presence of conditions for the realization of the transmission of vibrios by the water route. 相似文献
62.
The effects of culture conditions on abscisic acid (ABA)-inducedfreezing tolerance were determined in smooth bromegrass Bromusinermis Leyss cv. Manchar) cell suspension cultures. Bromegrasscultures initiated with 2 g fr wt of cells achieved maximumfreezing tolerances (greater than 32?C) at 25 to 30?Cin the presence of 75 to 100 µM ABA. High levels of freezingtolerance induced by ABA were correlated with high growth ratesat 25 and 30?C. In control cells, incubation at 10?C inducedoptimum levels of hardiness with minimal growth. Prolonged exposure(6 weeks) of cells to 3?C, with or without ABA, increased freezingtolerance only by several degrees. Exogenous ABA concentrationsgreater than 100 µM were not inhibitory to growth. Repeatedexposure to ABA, however, retarded growth and made the cellstolerant to temperatures below 40?C. Removal of ABA fromthe medium resulted in dehardening of the cells both at 25 and3?C. Nitrogen had a marginal effect on ABA-induced hardeningat 25?C, but inhibited age-dependent hardening of control cellcultures. Light had no effect on the freezing tolerance of culturedcells. Addition of 10% sucrose, 30 min prior to freezing, tobromegrass cells treated with ABA for 4 days increased freezingtolerance more than 15?C. These observations are discussed inrelation to the contrasting behaviour of the low temperatureand photoperiod dependent cold acclimation of plants (Received July 14, 1989; Accepted October 23, 1989) 相似文献
63.
L F Cherniatina V F Berezhno? A A Tulupova 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》1990,(4):36-40
A method has been developed for the evaluation of the effectiveness of bifidumbacterin in different quantitative morbidity characteristics in purulent inflammatory diseases of newborns in risk groups. This method requires a limited number of observations. In purulent inflammatory infections bifidumbacterin can be used as an effective remedy for the prophylaxis of hospital infections. The proposed method may be used for the analysis of the effectiveness of other antiepidemic measures, e.g. the sanitation of carriers. 相似文献
64.
Mutations in yeast proliferating cell nuclear antigen define distinct sites for interaction with DNA polymerase delta and DNA polymerase epsilon. 总被引:7,自引:2,他引:5 下载免费PDF全文
J C Eissenberg R Ayyagari X V Gomes P M Burgers 《Molecular and cellular biology》1997,17(11):6367-6378
The importance of the interdomain connector loop and of the carboxy-terminal domain of Saccharomyces cerevisiae proliferating cell nuclear antigen (PCNA) for functional interaction with DNA polymerases delta (Poldelta) and epsilon (Pol epsilon) was investigated by site-directed mutagenesis. Two alleles, pol30-79 (IL126,128AA) in the interdomain connector loop and pol30-90 (PK252,253AA) near the carboxy terminus, caused growth defects and elevated sensitivity to DNA-damaging agents. These two mutants also had elevated rates of spontaneous mutations. The mutator phenotype of pol30-90 was due to partially defective mismatch repair in the mutant. In vitro, the mutant PCNAs showed defects in DNA synthesis. Interestingly, the pol30-79 mutant PCNA (pcna-79) was most defective in replication with Poldelta, whereas pcna-90 was defective in replication with Pol epsilon. Protein-protein interaction studies showed that pcna-79 and pcna-90 failed to interact with Pol delta and Pol epsilon, respectively. In addition, pcna-90 was defective in interaction with the FEN-1 endo-exonuclease (RTH1 product). A loss of interaction between pcna-79 and the smallest subunit of Poldelta, the POL32 gene product, implicates this interaction in the observed defect with the polymerase. Neither PCNA mutant showed a defect in the interaction with replication factor C or in loading by this complex. Processivity of DNA synthesis by the mutant holoenzyme containing pcna-79 was unaffected on poly(dA) x oligo(dT) but was dramatically reduced on a natural template with secondary structure. A stem-loop structure with a 20-bp stem formed a virtually complete block for the holoenzyme containing pcna-79 but posed only a minor pause site for wild-type holoenzyme, indicating a function of the POL32 gene product in allowing replication past structural blocks. 相似文献
65.
Séverine Bontron V. Steimle Catherine Ucla Martha M. Eibl B. Mach 《Human genetics》1997,99(4):541-546
Congenital MHC class II deficiency or bare lymphocyte syndrome (BLS; McKusick 209920) is caused by defects in trans-acting
regulatory factors that control MHC class II expression and is therefore a disease of gene regulation. There are at least
four complementation groups and the genetic and molecular dissection of this rare disease has contributed considerably to
our current understanding of the molecular mechanisms governing MHC class II expression. Identification of the gene that is
defective in BLS complementation group A, CIITA (MHC class II transactivator), has led to the discovery that CIITA acts as
a master control factor of MHC class II expression. We have identified the CIITA mutations in a second patient from BLS group
A. Two novel mutations abolish CIITA function, as shown by transfection experiments. Molecular analysis of these two novel
mutations, together with the one described earlier in the first patient, is informative in terms of CIITA structure-function
relationships.
Received: 19 October 1996 / Revised: 25 November 1996 相似文献
66.
Rat liver deflavoxanthine dehydrogenase has been prepared by incubating native enzyme with calcium chloride. On reconstitution with FAD, about 85% of the original activity is recovered, all which is the O2-dependent type. In contrast, when dithiothreitol-treated deflavoenzyme is incubated with FAD, the recovery of activity is almost the same as above, but most of the recovered activity is of the NAD-dependent type. Deflavoenzyme with or without previous treatment with dithiothreitol was also reconstituted with two artificial FAD analogues, 8-mercapto-FAD and 6-OH-FAD. The difference spectra between the reconstituted enzymes and the initial deflavoenzyme indicate that, in each case, the FAD analogue is bound in its neutral form in dithiothreitol-treated enzyme, whereas it is bound in the anionic form in enzyme without previous dithiothreitol treatment. Furthermore, the protonated forms can be converted into the anionic forms on storage with a concomitant change of activity from the NAD-dependent to the O2-dependent type. This clearly indicates different environments around FAD in the two types of enzyme protein, which are shown to be interconvertible through oxidation-reduction of enzyme cysteinyl residues. 相似文献
67.
V. Vesterager 《BMJ (Clinical research ed.)》1997,314(7082):728-731
68.
Bazhenov M. A. Shernyukov A. V. Kupryushkin M. S. Pyshnyi D. V. 《Russian Journal of Bioorganic Chemistry》2019,45(6):699-708
Russian Journal of Bioorganic Chemistry - In this work, we introduce a novel nuanced analysis of the chemical transformations occurs during the automatic synthesis of phosphoryl guanidine... 相似文献
69.
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