Effects of Isoflavone-Enriched Feed on the Rumen Microbiota in Dairy Cows

In this study, we compared the effects of two diets containing different isoflavone concentrations on the isoflavone transfer from feed into milk and on the rumen microbiota in lactating dairy cows. The on-farm experiment was conducted on twelve lactating Czech Fleckvieh x Holstein cows divided into two groups, each with similar mean milk yield. Twice daily, cows were individually fed a diet based on maize silage, meadow hay and supplemental mixture. Control group (CTRL) received the basal diet while the experimental group (EXP) received the basal diet supplemented with 40% soybean isoflavone extract. The average daily isoflavone intake in the EXP group (16 g/day) was twice as high as that in the CTRL group (8.4 g/day, P<0.001). Total isoflavone concentrations in milk from the CTRL and EXP groups were 96.89 and 276.07 μg/L, respectively (P<0.001). Equol concentrations in milk increased from 77.78 μg/L in the CTRL group to 186.30 μg/L in the EXP group (P<0.001). The V3-4 region of bacterial 16S rRNA genes was used for metagenomic analysis of the rumen microbiome. The experimental cows exhibited fewer OTUs at a distance level of 0.03 compared to control cows (P<0.05) and reduced microbial richness compared to control cows based on the calculated Inverse Simpson and Shannon indices. Non-metric multidimensional scaling analysis showed that the major contributor to separation between the experimental and control groups were changes in the representation of bacteria belonging to the phyla Bacteroidetes, Proteobacteria, Firmicutes, and Planctomycetes. Surprisingly, a statistically significant positive correlation was found only between isoflavones and the phyla Burkholderiales (r = 0.65, P<0.05) and unclassified Betaproteobacteria (r = 0.58, P<0.05). Previous mouse and human studies of isoflavone effects on the composition of gastrointestinal microbial populations generally report similar findings.     

Cell penetration to nanofibrous scaffolds: Forcespinning?, an alternative approach for fabricating 3D nanofibers

Cell infiltration is a critical parameter for the successful development of 3D matrices for tissue engineering. Application of electrospun nanofibers in tissue engineering has recently attracted much attention. Notwithstanding several of their advantages, small pore size and small thickness of the electrospun layer limit their application for development of 3D scaffolds. Several methods for the pore size and/or electrospun layer thickness increase have been recently developed. Nevertheless, tissue engineering still needs emerging of either novel nanofiber-enriched composites or new techniques for 3D nanofiber fabrication. Forcespinning® seems to be a promising alternative. The potential of the Forcespinning® method is illustrated in preliminary experiment with mesenchymal stem cells.     

Metabolic regulation in progression to autoimmune diabetes

Recent evidence from serum metabolomics indicates that specific metabolic disturbances precede β-cell autoimmunity in humans and can be used to identify those children who subsequently progress to type 1 diabetes. The mechanisms behind these disturbances are unknown. Here we show the specificity of the pre-autoimmune metabolic changes, as indicated by their conservation in a murine model of type 1 diabetes. We performed a study in non-obese prediabetic (NOD) mice which recapitulated the design of the human study and derived the metabolic states from longitudinal lipidomics data. We show that female NOD mice who later progress to autoimmune diabetes exhibit the same lipidomic pattern as prediabetic children. These metabolic changes are accompanied by enhanced glucose-stimulated insulin secretion, normoglycemia, upregulation of insulinotropic amino acids in islets, elevated plasma leptin and adiponectin, and diminished gut microbial diversity of the Clostridium leptum group. Together, the findings indicate that autoimmune diabetes is preceded by a state of increased metabolic demands on the islets resulting in elevated insulin secretion and suggest alternative metabolic related pathways as therapeutic targets to prevent diabetes.     

Euglena gracilis and Trypanosomatids Possess Common Patterns in Predicted Mitochondrial Targeting Presequences

Euglena gracilis possessing chloroplasts of secondary green algal origin and parasitic trypanosomatids Trypanosoma brucei, Trypanosoma cruzi and Leishmania major belong to the protist phylum Euglenozoa. Euglenozoa might be among the earliest eukaryotic branches bearing ancestral traits reminiscent of the last eukaryotic common ancestor (LECA) or missing features present in other eukaryotes. LECA most likely possessed mitochondria of endosymbiotic ??-proteobacterial origin. In this study, we searched for the presence of homologs of mitochondria-targeted proteins from other organisms in the currently available EST dataset of E. gracilis. The common motifs in predicted N-terminal presequences and corresponding homologs from T. brucei, T. cruzi and L. major (if found) were analyzed. Other trypanosomatid mitochondrial protein precursor (e.g., those involved in RNA editing) were also included in the analysis. Mitochondrial presequences of E. gracilis and these trypanosomatids seem to be highly variable in sequence length (5?C118 aa), but apparently share statistically significant similarities. In most cases, the common (M/L)RR motif is present at the N-terminus and it is probably responsible for recognition via import apparatus of mitochondrial outer membrane. Interestingly, this motif is present inside the predicted presequence region in some cases. In most presequences, this motif is followed by a hydrophobic region rich in alanine, leucine, and valine. In conclusion, either RR motif or arginine-rich region within hydrophobic aa-s present at the N-terminus of a preprotein can be sufficient signals for mitochondrial import irrespective of presequence length in Euglenozoa.     

Selective forces for the origin of spliceosomes

It has been proposed that eukaryotic spliceosomes evolved from bacterial group II introns via constructive neutral changes. However, a more likely interpretation is that spliceosomes and group II introns share a common undefined RNA ancestor--a proto-spliceosome. Although, the constructive neutral evolution may have probably played some roles in the development of complexity including the evolution of modern spliceosomes, in fact, the origin, losses and the retention of spliceosomes can be explained straight-forwardly mainly by positive and negative selection: (1) proto-spliceosomes evolved in the RNA world as a mechanism to excise functional RNAs from an RNA genome and to join non-coding information (ancestral to exons) possibly designed to be degraded. (2) The complexity of proto-spliceosomes increased with the invention of protein synthesis in the RNP world and they were adopted for (a) the addition of translation signal to RNAs via trans-splicing, and for (b) the exon-shuffling such as to join together exons coding separate protein domains, to translate them as a single unit and thus to facilitate the molecular interaction of protein domains needed to be assembled to functional catalytic complexes. (3) Finally, the spliceosomes were adopted for cis-splicing of (mainly) non-coding information (contemporary introns) to yield translatable mRNAs. (4) Spliceosome-negative organisms (i.e., prokaryotes) have been selected in the DNA-protein world to save a lot of energy. (5) Spliceosome-positive organisms (i.e., eukaryotes) have been selected, because they have been completely spliceosome-dependent.     

Core/shell nanofibers with embedded liposomes as a drug delivery system

The broader application of liposomes in regenerative medicine is hampered by their short half-life and inefficient retention at the site of application. These disadvantages could be significantly reduced by their combination with nanofibers. We produced 2 different nanofiber-liposome systems in the present study, that is, liposomes blended within nanofibers and core/shell nanofibers with embedded liposomes. Herein, we demonstrate that blend electrospinning does not conserve intact liposomes. In contrast, coaxial electrospinning enables the incorporation of liposomes into nanofibers. We report polyvinyl alcohol-core/poly-ε-caprolactone-shell nanofibers with embedded liposomes and show that they preserve the enzymatic activity of encapsulated horseradish peroxidase. The potential of this system was also demonstrated by the enhancement of mesenchymal stem cell proliferation. In conclusion, intact liposomes incorporated into nanofibers by coaxial electrospinning are very promising as a drug delivery system.