No abstract

Few studies have evaluated the usefulness of fecal calprotectin (FC) or magnetic resonance enterography (MRE) in diagnosing active Crohn’s disease (CD) of the small bowel. In the study, we investigated the reliability of FC and MRE in assessing the activity of ileal CD and further explored the relationship between levels of FC and MRE scores. A total of 221 patients were diagnosed with ileal or ileo-colitis CD in our department between July 2012 and October 2016. The global magnetic resonance index of activity (MaRIA) correlated with the simple endoscopic score for CD (SES-CD) (r = 0.527, P = 0.005). When analysed segment-by-segment, a significant correlation was still observed (r = 0.590, P < 0.001). The SES-CD correlated closest with FC (r = 0.503), followed by CRP (r = 0.461), ESR (0.377) and the CDAI (r = 0.320). In receiver operating characteristic (ROC) analyses, the FC cut-off value of mucosal healing was 213.1 μg/g, with 76.1% sensitivity and 66.7% specificity. As for MaRIA, a cut-off value of 6.8 for each segment provided a sensitivity of 100% and a specificity of 79.2%. No agreement between MaRIA and FC levels was found. In conclusion, a combination of FC levels and MaRIA could be effective in monitoring mucosal activity in patients with small bowel CD.

Coenzyme Q10 (CoQ10) is an important component of the respiratory chain in humans and some bacteria. As a high-value-added nutraceutical antioxidant, CoQ10 has excellent capacity to prevent cardiovascular disease. The content of CoQ10 in the industrial Rhodobacter sphaeroides HY01 is hundreds of folds higher than normal physiological levels. In this study, we found that overexpression or optimization of the synthetic pathway failed CoQ10 overproduction in the HY01 strain. Moreover, under phosphate- limited conditions (decreased phosphate or in the absence of inorganic phosphate addition), CoQ10 production increased significantly by 12% to220 mg/L, biomass decreased by 12%, and the CoQ10 productivity of unit cells increased by 27%. In subsequent fed-batch fermentation, CoQ10 production reached 272 mg/L in the shake-flask fermentation and 1.95 g/L in a 100-L bioreactor under phosphate limitation. Furthermore, to understand the mechanism associated with CoQ10 overproduction under phosphate- limited conditions, the comparatve transcriptome analysis was performed. These results indicated that phosphate limitation combined with glucose fed-batch fermentation represented an effective strategy for CoQ10 production in the HY01. Phosphate limitation induced a pleiotropic effect on cell metabolism, and that improved CoQ10 biosynthesis efficiency was possibly related to the disturbance of energy metabolism and redox potential.

No abstract

No abstract

The versatile photosynthetic α-proteobacterium Rhodobacter sphaeroides , has recently been extensively engineered as a novel microbial cell factory (MCF) to produce pharmaceuticals, nutraceuticals, commodity chemicals and even hydrogen. However, there are no well-characterized high-activity promoters to modulate gene transcription during the engineering of R. sphaeroides . In this study, several native promoters from R. sphaeroides JDW-710 (JDW-710), an industrial strain producing high levels of co-enzyme Q 10 (Q 10 ) were selected on the basis of transcriptomic analysis. These candidate promoters were then characterized by using gusA as a reporter gene. Two native promoters, P rsp _ 7571 and P rsp _ 6124 , showed 620% and 800% higher activity, respectively, than the tac promoter, which has previously been used for gene overexpression in R. sphaeroides. In addition, a P rsp _ 7571 -derived synthetic promoter library with strengths ranging from 54% to 3200% of that of the tac promoter, was created on the basis of visualization of red fluorescent protein (RFP) expression in R. sphaeroides . Finally, as a demonstration, the synthetic pathway of Q 10 was modulated by the selected promoter T334* in JDW-710; the Q 10 yield in shake-flasks increased 28% and the production reached 226 mg/L . These well-characterized promoters should be highly useful in current synthetic biology platforms for refactoring the biosynthetic pathway in R. sphaeroides -derived MCFs.

No abstract

No abstract