High-level production of recombinant His-tagged rhamnulose 1-phosphate aldolase in Escherichia coli

9 pages, 8 figures, 2 tables.-- Printed version published Nov 2003.An expression system based on Escherichia coli and the T5 promoter allowed the overproduction of a his-tagged rhamnulose-1-phosphate aldolase (RhuA; EC 4.1.2.19), an enzyme with applications in the production of deoxyazasugars and deoxysugars compounds. Shake flask and bioreactor cultivation with E coli M15 (pQErham) were performed under different media and inducing conditions for RhuA expression. A Defined Medium (DM) with glucose as carbon source gave a high volumetric and enzyme productivity (3460 AU dm-3 and 288 AU dm-3 h-1 respectively) compared with Luria-Bertoni (LB) medium (2292 AU dm- 3 and 255 AU dm-3 h-1). The minimum quantity of (isopropyl--D-thiogalactoside) IPTG for optimal induction was estimated in 18-20 ºmol IPTG gDCW-1. The highest volumetric production of RhuA (8333 AU dm-3) was obtained when IPTG was added in the late log-phase. No significant differences were found in specific RhuA activity for induction temperatures of 30 and 37 ºC. An effective two-step purification process comprising affinity chromatography and gel permeation has been developed (overall recovery 66.5%). These studies provide the basis for the further development of an integrated process for recombinant RhuA production suitable for biotransformation applications.Financial support from CICYT (Projects: BIO99-1219-C02-01 and PPQ 2002-04625-C02-01). The Department of Chemical Engineering is the Unit of Biochemical Engineering of the Centre de Referència en Biotecnologia de la Generalitat de Catalunya (CeRBa).Peer reviewe

Mid -and long-term changes in satiety-related hormones, lipid and glucose metabolism, and inflammation after a Mediterranean diet intervention with the goal of losing weight: a randomized, clinical trial

BackgroundObesity is produced by the enlargement of the adipose tissue. Functioning as an endocrine organ, it releases and receives information through a complex network of cytokines, hormones, and substrates contributing to a low-chronic inflammation environment. Diet and healthy habits play key roles in the prevention of obesity and its related pathologies. In this regard, there is a need to switch to healthier and more appetizing diets, such as the Mediterranean one. ObjectiveTo compare the mid-and long-term effects of two Mediterranean diet (MedDiet) interventions, one energy-reduced plus physical activity promotion versus a non-restrictive diet, on peripheral satiety-related hormones, weight loss, glucose/lipid metabolism, and pro-inflammatory markers in subjects with obesity/overweight and metabolic syndrome. Materials and methodsA randomized, lifestyle intervention was conducted in 23 Spanish centers, with a large cohort of patients presenting metabolic syndrome. Our study is a subproject set in IMIM (Hospital del Mar Research Institute). Participants were men and women, aged 55-75 and 60-75, respectively, who at baseline met at least three metabolic syndrome components. Subjects were assigned to two intervention groups: (1) an intensive lifestyle intervention with an energy-reduced MedDiet and physical activity promotion (intervention group) with the aim of weight loss; and (2) a normocaloric MedDiet (control). We quantified in a subsample of 300 volunteers from Hospital del Mar Research Institute (Barcelona), following analytes at baseline, 6 months, and 1 year: glucose, HbA1c, triglycerides, total cholesterol, high-density lipoprotein cholesterol, LDL cholesterol, C-peptide, ghrelin, GLP-1, glucagon, insulin, leptin, PAI-1, resistin, and visfatin. Anthropometric and classical cardiovascular risk factors were also determined. A multivariate statistical model was employed to compare the two groups. Linear mixed-effect models were performed to compare changes in risk factors and biomarkers between intervention groups and over time. ResultsCompared to participants in the control group, those in intervention one showed greater improvements in weight, waist circumference, insulin (P < 0.001), glucose metabolism-related compounds (P < 0.05), triglyceride-related lipid profile (P < 0.05), leptin, blood pressure, and pro-inflammatory markers such as PAI-1 (P < 0.001) at mid-and/or long-term. High-sensitivity C-reactive protein, resistin, and vifastin also decreased in both groups. ConclusionA weight loss intervention employing a hypocaloric MedDiet and physical activity promotion has beneficial effects on adiposity, glucose metabolism, lipid profile, leptin, and pro-inflammatory markers, such as PAI-1 in both mid-and long-term