RESUMEN
Uterine flushings were collected three times at predetermined intervals from 11 mixed-breed beef cows and cultured for Brucella abortus . Prior to sampling, all cows had aborted fetuses from which brucellae had been isolated. Initial collections were made between 21 and 34 days following abortion. The second flushing was conducted at the onset of injections used for inducing superovulation and the third flushing was conducted 6 to 8 days after the ensuing estrus. The latter two flushes were conducted between 60 and 120 days following abortion. Brucellae were isolated from uterine flushings collected from 6 of the 11 cows on the initial round of sampling. Cultures of all subsequent uterine flushings collected before and after injections for superovulation were negative. It was concluded that the superovulatory treatment is not likely to reactivate the release of brucellae into the uterine lumen during the period when embryos are normally collected.
RESUMEN
Eleven EcoRI DNA fragments from the genome of an isolate of channel catfish virus (CCV) were cloned into the bacterial vector pUC19. The cloned DNA fragments ranged in size from approximately 200 base pairs to greater than 5,400 base pairs and accounted for about 13.5% of the 130,000-base pair CCV genome. Nine of these CCV DNA fragments encoded sequences that were expressed during late CCV infection. Channel catfish (total length, 4 cm) injected with CCV expressed CCV mRNA at detectable amounts in greater than or equal to 1 tissues. Uninjected control fish failed to express CCV-specific mRNA or expressed CCV-specific mRNA at lower amounts because of the presence of endogenous CCV. Tissue samples from clinically normal channel catfish fingerlings from 2 other farms as well as from adult brood stock also expressed CCV-specific mRNA. The results suggest that CCV can persist in a dormant or transcriptionally active state without causing clinical disease.
Asunto(s)
Bagres , ADN Viral/genética , Enfermedades de los Peces/microbiología , Infecciones por Herpesviridae/veterinaria , Herpesviridae/genética , Ictaluridae , Animales , Southern Blotting , Línea Celular , Clonación Molecular , Sondas de ADN , Desoxirribonucleasa EcoRI , Femenino , Regulación de la Expresión Génica , Infecciones por Herpesviridae/microbiología , Masculino , Hibridación de Ácido Nucleico , ARN Mensajero/biosíntesis , ARN Mensajero/genética , ARN Viral/biosíntesis , ARN Viral/genética , Mapeo RestrictivoRESUMEN
Induction of c-fos mRNA levels associated with the stimulation of growth by fetal bovine serum following quiescence was examined in three cell types following brief (24 h) serum starvation. Starved NIH-3T3 and HeLa S3 cells experienced c-fos mRNA induction 20-30 min after addition of serum. In contrast, Swiss-3T3 cells expressed c-fos constitutively following serum starvation. The pattern of oncogene expression coincided with the level of quiescence of each cell line prior to induction. Serum inductions of c-fos expression was dependent upon the response of each cell line to serum starvation, c-fos expression was also examined in HeLa S3 cells that had been separated into sequential cell cycle phases by centrifugal elutriation, c-fos expression peaked during the earliest part of the synchronous G1 phase. The amount of c-fos mRNA measured was approximately twice that found during other cell cycle phases. This suggests that, in addition to its role during the transition from quiescence, the c-fos gene product may play a regulatory role during the earliest part of G1 phase of the continuous cell cycle.