Selected nondigestible carbohydrates and prebiotics support the growth of probiotic fish bacteria mono-cultures in vitro

To search for nondigestible but fermentable (NDF) carbohydrates and prebiotics with a potency to promote the growth of selected bacteria in vitro. The growth of three reference bacteria strains Bacillus subtilis LMG 7135(T), Carnobacterium piscicola LMG 9839, Lactobacillus plantarum LMG 9211 and one candidate probiotic bacteria Lactobacillus delbrueckii subsp. lactis was investigated over a minimum period of 48 h in the presence of beta-glucan, xylo-oligosaccharide, arabinoxylo-oligosaccharide, inulin, oligofructose and glucose. Besides the capability to grow on inulin and oligofructose containing media, a distinct high growth in beta-glucan based substrates and a low growth in (arabino)xylooligosaccharide containing media were evident for most bacteria tested. With the exception of B. subtilis and L. plantarum, other bacteria grew equally well or even better on different substrates than on glucose. The fermentation of studied carbohydrates by these micro-organisms was dominated by the production of acetic acid as the main short chain fatty acid. Selected bacteria are able to ferment and grow on NDF and prebiotic carbohydrates but in a substrate dependent manner. This study delivers a first screening of which NDF or prebiotic carbohydrates are the most promising for aquaculture feed supplementations

Comparative prebiotic activity of mixtures of cereal grain polysaccharides

The main components of the non-starch polysaccharide (NSP) fraction of wheat flour are arabinoxylan (AX) and β-glucan. These are also present in other cereal grains, but their proportions vary with AX being the major component in wheat and rye and β-glucan in barley and oats. Therefore, it was hypothesised that these NSPs could act synergistically when fermented in vitro at the ratios present in the major foods consumed, resulting in increased prebiotic activity. AX and β-glucan were therefore tested in in vitro fermentation studies to assess their prebiotic activity when used individually and/or in different ratios. Short-chain fatty-acids (SCFAs) produced from in vitro fermentation were measured using HPLC and bacterial populations were measured using flow cytometry with fluorescence in situ hybridisation (Flow-FISH). Fermentation of AX alone resulted in a significant bifidogenic activity and increased concentrations of SCFAs, mainly acetate, after 8-24 h of fermentation, however β-glucan alone did not show prebiotic activity. The greatest prebiotic activity, based on concentration of total SCFAs and increases in total bacteria as well as beneficial Bifidobacterium and Clostridium coccoides/Eubacterium groups, was observed when AX and β-glucan were combined at a 3:1 ratio, which corresponds to their ratios in wheat flour which is major source of cereal fibre in the diet. This indicates that the population of bacteria in the human GI tract may be modulated by the composition of the fibre in the diet, to maximise the prebiotic potential

Plasma Cholesterol-Induced Lesion Networks Activated before Regression of Early, Mature, and Advanced Atherosclerosis

Plasma cholesterol lowering (PCL) slows and sometimes prevents progression of atherosclerosis and may even lead to regression. Little is known about how molecular processes in the atherosclerotic arterial wall respond to PCL and modify responses to atherosclerosis regression. We studied atherosclerosis regression and global gene expression responses to PCL (>= 80%) and to atherosclerosis regression itself in early, mature, and advanced lesions. In atherosclerotic aortic wall from Ldlr(-/-)Apob(100/100)Mttp(flox/flox)Mx1-Cre mice, atherosclerosis regressed after PCL regardless of lesion stage. However, near-complete regression was observed only in mice with early lesions; mice with mature and advanced lesions were left with regression-resistant, relatively unstable plaque remnants. Atherosclerosis genes responding to PCL before regression, unlike those responding to the regression itself, were enriched in inherited risk for coronary artery disease and myocardial infarction, indicating causality. Inference of transcription factor (TF) regulatory networks of these PCL-responsive gene sets revealed largely different networks in early, mature, and advanced lesions. In early lesions, PPARG was identified as a specific master regulator of the PCL-responsive atherosclerosis TF-regulatory network, whereas in mature and advanced lesions, the specific master regulators were MLL5 and SRSF10/XRN2, respectively. In a THP-1 foam cell model of atherosclerosis regression, siRNA targeting of these master regulators activated the time-point-specific TF-regulatory networks and altered the accumulation of cholesterol esters. We conclude that PCL leads to complete atherosclerosis regression only in mice with early lesions. Identified master regulators and related PCL-responsive TF-regulatory networks will be interesting targets to enhance PCL-mediated regression of mature and advanced atherosclerotic lesions. Author Summary The main underlying cause of heart attacks and strokes is atherosclerosis. One strategy to prevent these often deadly clinical events is therefore either to slow atherosclerosis progression or better, induce regression of atherosclerotic plaques making them more stable. Plasma cholesterol lowering (PCL) is the most efficient way to induce atherosclerosis regression but sometimes fails to do so. In our study, we used a mouse model with elevated LDL cholesterol levels, similar to humans who develop early atherosclerosis, and a genetic switch to lower plasma cholesterol at any time during atherosclerosis progression. In this model, we examined atherosclerosis gene expression and regression in response to PCL at three different stages of atherosclerosis progression. PCL led to complete regression in mice with early lesions but was incomplete in mice with mature and advanced lesions, indicating that early prevention with PCL in individuals with increased risk for heart attack or stroke would be particularly useful. In addition, by inferring PCL-responsive gene networks in early, mature and advanced atherosclerotic lesions, we identified key drivers specific for regression of early (PPARG), mature (MLL5) and advanced (SRSF10/XRN2) atherosclerosis. These key drivers should be interesting therapeutic targets to enhance PCL-mediated regression of atherosclerosis

Application of tailor-made membranes in a multi-stage process for the purification of sweeteners from Stevia rebaudiana

In this paper the performance of a three stage process with commercial as well as tailor-made polyether-sulphone (PES) membranes for the purification of sweeteners from Stevia rebaudiana Bertoni was evaluated. Retentions of the sweeteners for a synthetic mixture and plant extract in combination with flux decline measurements indicated that, in contrast with the lab-made membranes, on most commercial membranes a foulant layer was formed that influenced the separation performance negatively. For the plant extract, the best commercial membrane (PW010) had a selectivity and flux similar to the best lab-made membrane (27% PES), but the lab-made membrane was preferred because it showed a slightly lower retention of the sweeteners, as desired. Starting from an extract purity of 11% with the overall process (microfiltration, ultrafiltration, nanofiltration) a purity of 37% and a yield of 30% could be reached. (C) 2010 Elsevier Ltd. All rights reserved.status: publishe

Application of tailor-made membranes in a multi-stage process for the purification of sweeteners from Stevia rebaudiana.

a b s t r a c t In this paper the performance of a three stage process with commercial as well as tailor-made polyethersulphone (PES) membranes for the purification of sweeteners from Stevia rebaudiana Bertoni was evaluated. Retentions of the sweeteners for a synthetic mixture and plant extract in combination with flux decline measurements indicated that, in contrast with the lab-made membranes, on most commercial membranes a foulant layer was formed that influenced the separation performance negatively. For the plant extract, the best commercial membrane (PW010) had a selectivity and flux similar to the best lab-made membrane (27% PES), but the lab-made membrane was preferred because it showed a slightly lower retention of the sweeteners, as desired. Starting from an extract purity of 11% with the overall process (microfiltration, ultrafiltration, nanofiltration) a purity of 37% and a yield of 30% could be reached