Short communication: Viable Mycobacterium avium subspecies paratuberculosis in retail artisanal Coalho cheese from Northeastern Brazil.

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.

Alpha-ketoisocaproate increases the in vitro 32P incorporation into intermediate filaments in cerebral cortex of rats.

In this study we investigated the effects of alpha-ketoisocaproic (KIC), alpha-ketoisovaleric (KIV) and alpha-keto-beta-methylvaleric (KMV) acids on the phosphorylation of intermediate filament (IF) proteins of cerebral cortex of rats. Tissue slices were incubated with [32P] orthophosphate in the presence or absence of the acids. The intermediate filament enriched cytoskeletal fraction was isolated and the radioactivity incorporated into neurofilament subunits, vimentin and glial fibrillary acidic protein was measured. Results demonstrated that KIC significantly increased phosphorylation of these proteins whereas the other acids had no effect. Experiments using protein kinase inhibitors indicated that the effect of KIC was mediated by Ca2+/calmodulin- and cAMP-dependent protein kinases. This study provides evidence that KIC, a key metabolite accumulating in maple syrup urine disease, increases phosphorylation of IF proteins.

Population kinetics of precursors of IL 2-producing peripheral T lymphocytes: evidence for short life expectancy, continuous renewal, and post-thymic expansion.

The fate of spleen T cell populations able to produce IL 2 after stimulation with Con A (IL 2p) was evaluated at different times after injection into IL 2p-deficient, syngeneic nude recipients. Precise enumeration of transferred cell populations in recipient organs was performed by limiting dilution analysis. The results obtained confirm previous findings on the short life-span of IL 2p cells. They also demonstrate that: the transferred populations containing IL 2p were capable of continuous renewal and expansion in the host; IL 2p cell expansion, a transient event that takes place predominantly in lymph nodes, is much reduced when injected cells are depleted of recent thymus migrants; in steady-state conditions, IL 2p T cells do not lose their self-renewal ability and maintain population sizes by continuous cell production and death in peripheral pools. The self-renewal capacity, the expansion potential of peripheral IL 2p T cells and, in particular, of recent thymus migrants may allow extensive post-thymic modulation of peripheral T cell specificities, suggesting that post-thymic selection may have a major role in the establishment of the available and actual mature IL 2p T cell repertoire.

Substrate-dependent differential expression of Humicola grisea var. thermoidea cellobiohydrolase genes.

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.

Phenylalanine inhibition of the phosphorylation of cytoskeletal proteins from cerebral cortex of young rats is prevented by alanine.

BACKGROUND: Phenylalanine has been considered the main responsible agent for the brain damage that occurs in phenylketonuria. METHODS AND RESULTS: In this work we studied the effect of this amino acid on the in vitro phosphorylation of cytoskeletal proteins of the cerebral cortex of rats. We observed that 2 mM phenylalanine, a concentration usually found in the plasma of phenylketonuric patients, decreased the in vitro 32P incorporation into these proteins. In addition, we investigated the effect of alanine on the inhibition of 32P incorporation into cytoskeletal proteins caused by phenylalanine. We observed that 0.5 mM alanine did not alter 32P incorporation but prevented the inhibition provoked by phenylalanine. CONCLUSION: In case the inhibition of cytoskeletal protein phosphorylation by phenylalanine also occurs in human phenylketonuria, it is possible that alanine supplementation to the phenylalanine-restricted diet may be beneficial to these patients.