RESUMO
The cDNA sequence of bovine prochymosin gene was cloned and sequenced from the abomasums of suckling calf by RT-PCR. The sequence was aligned and bioinformatically analyzed with related sequences in GenBank. The result of sequence analysis revealed that the gene was determined to bovine prochymosin B gene and had the high level of homology with prochymosin gene of other known mammals. The base bias of 18 species of prochymosin gene reduced according to codon position, and the gene provided us with excellent material of phylogenetic research. Thus, the phylogenetic tree of 18 species of prochymosin gene was used to discuss and offer testimony to phylogenetic relationship of 11 mammals.
Assuntos
Quimosina/genética , Clonagem Molecular/métodos , Precursores Enzimáticos/genética , Filogenia , Animais , Animais Recém-Nascidos , Bovinos , Quimosina/classificação , Precursores Enzimáticos/classificação , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Abstract: The major flavor substances Lactic acid bacteria produced include the buttermilk aroma butanedione, the yoghurt flavor acetaldehyde and the amino acid. Metabolic engineering in LAB had focused primarily on rerouting of pyruvate metabolism towards butanedione or acetaldehyde to improve the flavor of fermented milk, which has considerable economic value. The typical yogurt flavor is caused by acetaldehyde produced through many different pathways. The attention was focused on one specific reaction for acetaldehyde formation catalyzed by serine hydroxymethyltransferase, which encoded by the glyA gene. In addition, the efficient conversion of glucose into acetaldehyde was achieved by over-expression of pyruvate decarboxylase and NADH oxidase in LAB. The concentration of acetaldehyde derived from this regulation is higher than the other strategy. As for the regulation of butanedione, it was focused on combinating inactivation of alpha-acetolactate decarboxylase with low lactate dehydrogenase activity, or with overproduction of NADH-oxidase, or with overproduction of alpha-acetolactate synthase. Then the possibility of co-regulation with certain three kinds of enzyme above was recommended.