ABSTRACT
Pyrroloquinoline quinone (PQQ), an important redox enzyme cofactor, has many physiological and biochemical functions, and is widely used in food, medicine, health and agriculture industry. In this study, PQQ production by recombinant Gluconobacter oxydans was investigated. First, to reduce the by-product of acetic acid, the recombinant strain G. oxydans T1 was constructed, in which the pyruvate decarboxylase (GOX1081) was knocked out. Then the pqqABCDE gene cluster and tldD gene were fused under the control of endogenous constitutive promoter P0169, to generate the recombinant strain G. oxydans T2. Finally, the medium composition and fermentation conditions were optimized. The biomass of G. oxydans T1 and G. oxydans T2 were increased by 43.02% and 38.76% respectively, and the PQQ production was 4.82 and 20.5 times higher than that of the wild strain, respectively. Furthermore, the carbon sources and culture conditions of G. oxydans T2 were optimized, resulting in a final PQQ yield of (51.32±0.899 7 mg/L), 345.6 times higher than that of the wild strain. In all, the biomass of G. oxydans and the yield of PQQ can be effectively increased by genetic engineering.
Subject(s)
Fermentation , Gene Knockout Techniques , Gluconobacter oxydans , Genetics , Metabolism , Industrial Microbiology , Methods , Multigene Family , Genetics , Organisms, Genetically Modified , PQQ Cofactor , Genetics , Promoter Regions, Genetic , GeneticsABSTRACT
Objective:To investigate the clinical significance of Bcl-6, c-myc gene abnormalities in Xinjiang Uygur and Han dif-fused large B-cell lymphoma (DLBCL) subtypes. Methods:Bcl-6, c-myc gene was detected by fluorescence in situ hybridization in 233 patients with DLBCL . A relationship was observed among Bcl-6, c-myc gene translocation, and clinical data in DLBCL patients. In addition, a difference was observed among Bcl-6, c-myc gene translocation, and different ethnic groups in different subtypes of DLB-CL. Results:Among the 233 patients, 51 cases (21.89%) had rearranged Bcl 6 gene, and 39 cases (16.74%) had rearranged c-myc gene. Bcl-6 gene translocation and expression was related with age, gender, disease location, clinical stage, and LDH levels (P>0.05), but was not related with nationality , international prognostic index score, extranodal involvement, B symptoms, DLBCL subtypes, and recent efficacy (P0.05), but was not related with nationality, IPI score, extranodal involvement, B symptoms, and recent effica-cy (P0.05). By con-trast, in the Uygur and Han non-GCB groups, Bcl-6, c-myc gene translocation showed significant difference (P>0.05). Conclusion:Bcl-6, C-myc gene translocation was related with age, gender, disease location, clinical stage, and LDH levels. Bcl-6 gene translocation was also correlated with different subtypes of DLBCL.