RESUMO
Lipase-producing bacteria are naturally-occurring, industrially-relevant microorganisms that produce lipases, which can be used to synthesize biodiesel from waste oils. The efficiency of lipase expression varies between various microbial strains. Therefore, strains that can produce lipases with high efficiency must be screened, and the conditions of lipase metabolism and optimization of the production process in a given environment must be thoroughly studied. A high efficiency lipase-producing strain was isolated from the sediments of Jinsha River, identified by 16S rRNA sequence analysis as Serratia marcescens, and designated as HS-L5. A schematic diagram of the genome sequence was constructed by high-throughput genome sequencing. A series of genes related to lipid degradation were identified by functional gene annotation through sequence homology analysis. A genome-scale metabolic model of HS-ML5 was constructed using systems biology techniques. The model consisted of 1722 genes and 1567 metabolic reactions. The topological graph of the genome-scale metabolic model was compared to that of conventional metabolic pathways using a visualization software and KEGG database. The basic components and boundaries of the tributyrin degradation subnetwork were determined, and its flux balance analyzed using Matlab and COBRA Toolbox to simulate the effects of different conditions on the catalytic efficiency of lipases produced by HS-ML5. We proved that the catalytic activity of microbial lipases was closely related to the carbon metabolic pathway. As production and catalytic efficiency of lipases varied greatly with the environment, the catalytic efficiency and environmental adaptability of microbial lipases can be improved by proper control of the production conditions.
Assuntos
Proteínas de Bactérias/metabolismo , Genoma Bacteriano/genética , Lipase/metabolismo , Biologia de Sistemas/métodosRESUMO
Ulcerative colitis (UC) is a chronic inflammation of the large intestine. The aim of this study was to investigate the association of two polymorphisms in STAT3 with the risk of UC development in the Chinese Han population. This is a hospital-based case-control study involving 56 UC patients and 274 controls. Genotyping was performed using the polymerase chain reaction with sequence-specific primers (PCR-SSP) method. Statistical analyses were conducted using logistic regression and genotype risk score. Overall, there was a significant difference between patients and controls in the genotype distribution of rs2293152 (P = 0.044). The risk for UC associated with the rs2293152-G mutant allele was increased (odds ratio = 2.76; 95% confidence interval = 1.06- 7.24) under the dominant model. However, we failed to find any obvious differences in the rs4796793 genotype or allele distributions between the UC patients and controls, and did not detect any significant association of the rs4796793 polymorphism with UC across different genetic models of inheritance. Our study implies that the STAT3 rs2293152 polymorphism may be associated with the occurrence of UC and might be used as a predictive factor for UC in the Chinese Han population.