Project description:The goal was to measure the postprandial effect of an oat bran meal on gene expression in leukocytes from healthy subjects and to investigate the postprandial glucose, insulin and triglyceride responses. Linear mixed models were used for the array data to study the simultaneous dependency on many factors and functional categories of genes whose expression were correlated with oat bran intake were determined.
Project description:Background & Aims: Non-alcoholic fatty liver disease (NALFLD)-associated changes in gut microbiota are important drivers of disease progression toward fibrosis. Therefore, reversing microbiota alterations could ameliorate NAFLD progression. Oat beta-glucan, a non-digestible polysaccharides, has shown promising therapeutic effects on hyperlipidemia associated with NAFLD, but its impact on gut microbiota and most importantly NAFLD fibrosis remains unknown. Methods: We performed detailed metabolic phenotyping including body composition, glucose tolerance, and lipid metabolism as well as comprehensive characterization of the gut-liver axis in a western-style diet (WSD)-induced model of NAFLD and assessed the effect of a beta-glucan intervention on early and advanced liver disease. Gut microbiota was modulated using broad-spectrum antibiotic (Abx) treatment. Results: Oat beta-glucan supplementation did not affect WSD-induced body weight gain, glucose intolerance, and the metabolic phenotype remained largely unaffected. Interestingly, oat beta-glucan dampened NAFLD inflammation, associated with significantly reduced monocyte-derived macrophages (MoMFs) infiltration, fibroinflammatory gene expression, and strongly reduced fibrosis development. Mechanistically, this protective effect was not mediated by changes in bile acid composition or signaling, but was dependent on gut microbiota and was lost upon Abx treatment. Specifically, oat beta-glucan partially reversed unfavorable changes in gut microbiota, resulting in an expansion of protective taxa, including Ruminococcus, and Lactobacillus followed by reduced translocation of TLR ligands. Conclusions: Our findings identify oat beta-glucan as a highly efficacious food supplement that dampens inflammation and fibrosis development in diet-induced NAFLD. These results, along with its favorable dietary profile, suggest that it may be a cost-effective and well-tolerated approach to preventing NAFLD progression and should be assessed in clinical studies.
Project description:Many existing centromeres may have originated as neocentromeres that activated de novo from non-centromeric regions. However, the evolutionary path from a neocentromere to a mature centromere has been elusive. Here we analyzed the centromeres of six chromosomes that were transferred from maize into oat as the result of an inter-species cross. Centromere size and location were assayed by chromatin immunoprecipitation for the histone variant CENH3, which is a defining feature of functional centromeres. Maize and oat are highly divergent and differ in genome size by four fold. Two isolates of maize chromosome proved to contain neocentromeres in the sense that they had moved from the original site, whereas the remaining seven centromeres (1, 2, 5, 6, 8, 9 and 10) were retained in the same area in both species. In all cases the CENH3-binding domains were dramatically expanded to encompass a larger area in the oat background (~4 Mb) than the average centromere size in maize (~2 Mb). The expansion of maize centromeres appeared to be restricted by the transcription of genes located in regions flanking the original centromeres. The results from the current study provide evidence that (1) centromere size is regulated; (2) centromere sizes tend to be uniform within a species regardless of chromosome size or origin of the centromere; and (3) neocentromeres emerge and expand preferentially in gene poor regions. Our results, together with data from several animal species, suggest that centromere size expansion may be a key factor in the survival of neocentric chromosomes in natural populations.
Project description:Pollen development in angiosperms is one of the most important processes controlling plant reproduction and thus productivity. At the same time, pollen development is highly sensitive to environmental fluctuations, including temperature, drought, and nutrition. Therefore, pollen biology is a major focus in applied studies and breeding approaches for improving plant productivity in a globally changing climate. The most accessible developmental stages of pollen are the mature pollen and the pollen tubes, and these are thus most frequently analyzed. To reveal a complete quantitative proteome map, we additionally addressed the very early stages, analyzing eight stages of tobacco pollen development: diploid microsporocytes, meiosis, tetrads, microspores, polarized microspores, bipolar pollen, desiccated pollen, and pollen tubes. A protocol for the isolation of the early stages was established. Proteins were extracted and analyzed by means of a new gel LC-MS fractionation protocol. In total, 3817 protein groups were identified. Quantitative analysis was performed based on peptide count. Exceedingly stage-specific differential protein regulation was observed during the conversion from the sporophytic to the gametophytic proteome. A map of highly specialized functionality for the different stages could be revealed from the metabolic activity and pronounced differentiation of proteasomal and ribosomal protein complex composition up to protective mechanisms such as high levels of heat shock proteins in the very early stages of development.
Project description:We determined nucleosome positions throughout the genome in diploid S. cerevisiae undergoing early stages of synchronous meiosis. This study sought to assess if systematic reorganization of nucleosomes occurs during meiotic prophase at or near sites of DNA double strand break formation.