RESUMO
Mycobacterium avium ssp. paratuberculosis (MAP) is the etiologic agent of paratuberculosis and it potentially plays a role in Crohn's disease. In humans, the main route of transmission of MAP might be the intake of contaminated milk and dairy products. Considering that MAP has already been detected in many types of cheese in different counties, and that Coalho cheese is an important dairy product in northeastern Brazil, the aim of this study was to report the first detection of MAP in retail Coalho cheese in Brazil by PCR and culture. Of 30 retail Coalho cheese samples, 3 (10%) amplified fragments of a similar size to that expected (626 bp) were obtained and viable MAP was recovered by culture from 1 (3.3%) sample. The DNA from the positive culture sample was sequenced and showed 99% identity with the insertion sequence IS900 deposited in GenBank. It was possible to identify the presence of MAP-specific DNA in the analyzed samples for the first time in Brazil, and to recover viable cells from retail Coalho cheese.
Assuntos
Queijo/microbiologia , Mycobacterium avium subsp. paratuberculosis/isolamento & purificação , Animais , Brasil , Contagem de Colônia Microbiana , Elementos de DNA Transponíveis , DNA Bacteriano/genética , Dados de Sequência Molecular , Mycobacterium avium subsp. paratuberculosis/genética , Reação em Cadeia da Polimerase , Análise de Sequência de DNARESUMO
Transcription of fungal cellulase genes may be affected by substrate induction. We studied the expression of Humicola grisea var. thermoidea cellobiohydrolase genes (cbh1.1 and cbh1.2) under induction by several soluble and insoluble carbon sources. Using the RT-PCR technique, the cbh1.2 transcript was detected in all the conditions assayed along the growth curve. Catabolite repression, which frequently occurs in other fungal celluloytic systems, was not observed. On the other hand, cbh1.1 transcription was shown to be driven by insoluble and complex lignocellulosic substrates. In summary, the cbh1.2 gene product is constitutively produced, while cbh1.1 seems to respond to a distinct regulatory mechanism.