RESUMEN
ABSTRACT Screening promising L. thermophiles with high productivity, high efficiency and strong adaptability are very important in lactic acid industry. For this purpose, 80MeV/u carbon ions were applied to irradiate L. thermophiles. After high-throughput screening, a mutant, named SRZ50, was obtained. Different carbon sources or nitrogen sources were provided to investigate carbon or nitrogen source utilization between mutant SRZ50 and wild type, and different fermentation periods were also chose to study fermentation characteristic between mutant SRZ50 and wild type. The results showed that mutant SRZ50 exhibited the enhanced L-(+)-lactic acid production from wild type. When glucose or fructose was the sole carbon source, the L(+)-lactic acid production by mutant SRZ50 was both the highest, respectively, 23.16 ± 0.72 g/L or 23.24 ± 0.66 g/L, which had a significant increase from that of wild type (P<0.01), following obvious increase in biomass (P<0.05). When yeast powder was the sole nitrogen source, it can promote mutant SRZ50 to accumulate the highest L-(+)-lactic acid accumulation, which also had a significant increase from that of wild type (P<0.01). Under different fermentation periods, it was obtained that mutant SRZ50 all exhibited significant increase in L-(+)-lactic acid accumulation from wild type. In conclusion, a mutant strain with improved production profiles for L-(+)-lactic acid, was obtained, indicating that heavy ions can be an efficient tool to improve metabolic product accumulations in microbes.
RESUMEN
To investigate the relationship of serum lipids and apolipoprotein [apoE] gene polymorphism to colorectal adenomas. This study took place in the Department of Gastroenterology, Renmin Hospital of Wuhan University, PR China from June 2003 to March 2005. Ninety-eight patients with colorectal adenomas and 40 healthy subjects were enrolled, and their serum levels of triglyceride [TG], total cholesterol [TC], high density lipoprotein cholesterol [HDL-C], and low density lipoprotein cholesterol [LDL-C] were determined. The apoE gene polymorphism was identified by polymerase chain reaction-restriction fragment length polymorphism [PCR-RFLP]. Serum TC levels of colorectal adenomas group [5.32 +/- 0.85 mmol/L], distal colorectal adenomas group [5.58 +/- 0.63 mmol/L], and villous adenoma group [5.49 +/- 0.69 mmol/L] were higher than the control group [4.28 +/- 0.62 mmol/L, p=0.016], proximal colorectal adenomas group [4.82 +/- 0.58 mmol/L, p=0.038] and non-villous adenoma group [4.76 +/- 0.58 mmol/L, p=0.03]. Serum HDL-C levels of colorectal adenomas group [1.39 +/- 0.25 mmol/L] were lower than the control group [1.51 +/- 0.29 mmol/L] [p=0.035]. Serum lipids levels of each genotype in colorectal adenomas group were not statistically significant. Apolipoprotein E3/E4 genotypic frequency in colorectal adenomas group [7.1%] was lower than the control group [17.5%] [p=0.012]. The findings suggest that altered lipid metabolism may be differentially associated with colorectal adenomas and the persons with apoE E3/E4 genotype have lower risk suffering from colorectal adenomas than those with other genotypes