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Mostrando 13-20 de 20 artigos, teses e dissertações.
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13. Distinct repertoire of antigenic variants of foot-and-mouth disease virus in the presence or absence of immune selection.
Antigenic variants of foot-and-mouth disease virus (FMDV) were generated and frequently became dominant in clonal populations of FMDV (clone C-S8c1) grown in the absence of anti-FMDV antibodies. We have now passaged eight samples of the same FMDV clone in the presence of a limited amount of neutralizing polyclonal antibodies directed to the major antigenic s
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14. Colonization of the large bowel by Clostridium difficile in healthy infants: quantitative study.
Colonization of the large bowel of healthy infants by Clostridium difficile was studied. Feces were collected from five breast-fed aand five formula-fed infants throughout the first year of life, and levels of C. difficile were quantitated. Three breast-fed and five formula-fed infants were colonized for periods of between 8 and 42 weeks, and another infant
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15. Peroxidases in Tobacco Abscission Zone Tissue: II. Time Course Studies of Peroxidase Activity during Ethylene-induced Abscission 1
Ethylene-induced abscission in flower pedicels of Nicotiana tabacum L. cv. Little Turkish causes a progressive increase in peroxidase activity during the first 4 hours of a 5-hour time course ethylene treatment period, with decrease in peroxidase activity occurring between 4 hours and 5 hours, when the supernatant extracts of abscission zone segments are tes
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16. Evaluation of the in vitro activity of BMY-28142, a new broad-spectrum cephalosporin.
The in vitro activity of BMY-28142, a new cephalosporin, was tested by a broth microdilution system and compared with those of cefotaxime, ceftazidime, cefoperazone, moxalactam, and HR 810 against 747 bacterial isolates, one-third of which were resistant to one or more third-generation cephalosporins. BMY-28142 was the most active drug tested against 326 Ent
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17. Effect of extracellular adenosine triphosphate on electrical properties of subconfluent Madin-Darby canine kidney cells.
1. The present study has been performed to test for an influence of extracellular ATP on the potential differences across the cell membrane (PD) in subconfluent MDCK cells utilizing conventional microelectrodes. 2. In the absence of ATP, the mean measured PD was -47.5 +/- 0.3 mV (+/- S.E.M., n = 320). Application of 10 mumol/l ATP leads to rapid (less than 2
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18. Epitopes and hemagglutination binding domain on subgenus B:2 adenovirus fibers.
The adenovirus fiber serves as a ligand between the virus and the host cell receptor and manifests hemagglutination (HA) activity and antigenic domains. We have screened both the antigenic and immunogenic epitopes on the adenovirus fibers of subgenus B:2 by using recombinant fiber proteins (rfibers) expressed in Escherichia coli, synthesized peptides (P1 to
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19. Structure-function analysis of the triphosphatase component of vaccinia virus mRNA capping enzyme.
The N-terminal 60 kDa (amino acids 1 to 545) of the D1 subunit of vaccinia virus mRNA capping enzyme is an autonomous bifunctional domain with triphosphatase and guanylyltransferase activities. We previously described two alanine cluster mutations, R77 to A (R77A)-K79A and E192A-E194A, which selectively inactivated the triphosphatase component. Here, we char
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20. kil-kor regulon of promiscuous plasmid RK2: structure, products, and regulation of two operons that constitute the kilE locus.
The kil-kor regulon of IncP plasmid RK2 is a complex regulatory network that includes genes for replication and conjugal transfer, as well as for several potentially host-lethal proteins encoded by the kilA, kilB, and kilC loci. While kilB is known to be involved in conjugal transfer, the functions of kilA and kilC are unknown. The coregulation of kilA and k