The genome of Bifidobacterium pseudocatenulatum IPLA 36007, a human intestinal strain with isoflavone-activation activity

Background: Bifidobacterium species, including Bifidobacterium pseudocatenulatum, are among the dominant microbial populations of the human gastrointestinal tract. They are also major components of many commercial probiotic products. Resident and transient bifidobacteria are thought to have several beneficial health effects. However, our knowledge of how these bacteria interact and communicate with host cells remains poor. This knowledge is essential for scientific support of their purported health benefits and their rational inclusion in functional foods. Results: This work describes the draft genome sequence of Bifidobacterium pseudocatenulatum IPLA 36007, a strain isolated as dominant from the feces of a healthy human. Besides several properties of probiosis, IPLA 36007 exhibited the capability of releasing aglycones from soy isoflavone glycosides. The genome contains 1,851 predicted genes, including 54 genes for tRNAs and fie copies of unique 16S, 23S and 5S rRNA genes. As key attributes of the IPLA 36007 genome we can mention the presence of a lysogenic phage, a cluster encoding type IV fimbriae, and a locus encoding a clustered, regularly interspaced, short, palindromic repeat (CRISPR)-Cas system. Four open reading frames (orfs) encoding \u3b2-glucosidases belonging to the glycosyl hydrolase family 3, which may act on isoflavone glycosides, were encountered. Additionally, one gene was found to code for a glycosyl hydrolase of family 1 that might also have \u3b2-glucosidase activity. Conclusion: The availability of the B. pseudocatenulatum IPLA 36007 genome should allow the enzyme system involved in the release of soy isoflavone aglycones from isoflavone glycosides, and the molecular mechanisms underlying the strain's probiotic properties, to be more easily understood

A new synonym for Eragrostis pilgeri (Poaceae: Eragrostideae)

Volume: 19Start Page: 1157End Page: 116

Differences between Isotropic and Self-Nucleated PCL Melts Detected by Dielectric Experiments

Melt memory effects on polymer crystallization are commonly reported in the literature, even when they are not completely understood. In particular, the exact nature of the melt heterogeneities that cause an enhanced nucleation (i.e., the "self-nuclei") is unknown. This is partly due to sensitivity limitations of the experimental techniques employed to study melt memory. In this work, the melt memory effect of semicrystalline polymers is studied for the first time by dielectric measurements. Polycaprolactones of two different molecular weights have been investigated. Isotropic or self-nucleated melt states are obtained, at a given experimental temperature, by cooling from the isotropic melt or heating from the semicrystalline solid, respectively. A detectable decrease in electrical permittivity is obtained for a self-nucleated melt, consistent with the presence of molecular dipoles with restricted mobility in the case of samples displaying crystalline memory. The volume fraction of repeating units involved in the formation of self-nuclei is estimated to be lower than 0.4%. The relative difference in dielectric permittivity between self-nucleated and isotropic melt state shows excellent correlation with rheological measurements that detect an increase in Newtonian viscosity and with the enhancement of nucleation density, measured by DSC. Each of these measured parameters showed a different sensitivity to the presence of self-nuclei, which is linked both to their nature and to the features of the specific measurements. It is suggested that the relatively strong memory effect displayed by PCL, which can be evidenced by different techniques, is related to the presence of weak intermolecular hydrogen-bonding interactions

Bioaccesibility of plant sterols and their oxides in enriched fruit and/or milk-based beverages

Plant sterols (PS) have many beneficial functions, like LDL-cholesterol reduction upon other effects on lipid parameters. PS are prone to oxidation and can give rise to plant sterol oxidation products (POPs), which have been suggested to be cytotoxic. The aim was to evaluate the bioaccesibility of phytosterols and their oxides in fruit and/or milk based beverages enriched with PS after a simulated gastrointestinal digestion. Four PS-fortified beverages were analyzed (fruit beverages without milk (Fb), with milk (Fb\u2019M), with &#946;-cryptoxanthin (FbM) and only milk (M)) and their corresponding bioaccessible fractions (BF). PS source was the same (0.7 g/100 g) for all the samples. The applied in vitro digestion method was according to Granado et al. (2007) to obtain the BF (soluble fraction). The extraction and purification of PS and POPs was achieved by lipid extraction (for the beverages), followed by saponification, unsaponificable extraction and silica SPE purification (only for POPs). They were determined by GC-FID (PS) and GC-MS (POPs). Total contents of PS in the analyzed beverages ranged between 607.08 and 743.05 mg/100 g beverage. The concentration order of PS was \u3b2-sitosterol > sitostanol > campesterol > stigmasterol > campestanol. A statistically significative (p <0.05) decrease in the PS content among beverages and the BAF (22.23-44.98 mg/100 g beverage) was observed, even though the relative percentages of the different PS were similar before and after digestion process. Total POP contents in the beverages ranged between 47.64 and 68.97 \u3bcg/100 g sample and 31.05-44.31 \u3bcg/100 g sample in the beverages and the BF, respectively. In all cases, \u3b2-sitosterol oxides (\u3b1/\u3b2-hydroxy, triol and 7-keto) were the only POPs detected. In the beverages, the most abundant oxide was 7-keto, whereas in the BF triol was the main one. The profile of POPs depended on the beverage or BF considered. Bioaccessibility (%) of PS and POPs were 2.99\u20137.41 and 34.17\u201393.01, respectively. The effect of simulated gastrointestinal digestion applied to PS and POPs studied, resulted to be different, showing that POPs bioaccessibility is much more higher than that of PS