RESUMO
The AEC-resistant aspartate kinase gene from C. crenatum CD945 was cloned into vector pJC1. Its expression was investigated both in the wild type C. crenatum AS1.542 and its mutant C. crenatum CD945. The result showed that C. crenatum AS1.542 harboring AK(fbr) gene could grow on the defined medium with the co-existence of 12 mg/mL both of AEC and L-threonine respectively. Overexpression of AK(fbr) gene in C. crenatum CD945 results in a 4-fold increase of specific enzyme activity than the parental strain. The amplification of the activity of aspartate kinase yields 22% increase of L-lysine production and 23% increase of L-lysine productivity without affecting the growth rate.
Assuntos
Aspartato Quinase/genética , Corynebacterium/enzimologia , Corynebacterium/genética , Corynebacterium/crescimento & desenvolvimento , Retroalimentação Fisiológica , Fermentação , Lisina/biossíntese , Recombinação GenéticaRESUMO
OBJECTIVE: To investigate the mutation in transcription factor paired box gene PAX9 in a mongolian family with non-syndromic oligodontia. METHODS: Peripheral blood was collected from 17 core family members (9 unaffected, 8 affected) in this Mongolian family with non-syndromic oligodontia. Mutation in exons of PAX9 gene was identified by PCR amplification and DNA sequencing. RESULTS: A point mutation c.87G > C at position 87 in exon 4 of PAX9 was identified from 8 affected members in the family, which were G/C heterozygous.While the 9 healthy members in the family were homozygous for C which was consistent with normal reference sequence in the GenBank(accession number: NC_000014). CONCLUSIONS: The mutation of c.87G > C (p. Ala240Pro) in exon 4 of PAX9 was likely to cause the non-syndromic oligodontia in this Mongolian family.