Enterocyte-specific deletion of metal transporter Zip14 (Slc39a14) alters intestinal homeostasis through epigenetic mechanisms.

Zinc has anti-inflammatory properties using mechanisms that are unclear. Zip14 (Slc39a14) is a zinc transporter induced by proinflammatory stimuli and is highly expressed at the basolateral membrane of intestinal epithelial cells (IECs). Enterocyte-specific Zip14 ablation (Zip14ΔIEC) in mice was developed to study the functions of this transporter in enterocytes. This gene deletion led to increased intestinal permeability, increased IL-6 and IFNγ expression, mild endotoxemia, and intestinal dysbiosis. RNA sequencing was used for transcriptome profiling. These analyses revealed differential expression of specific intestinal proinflammatory and tight junction (TJ) genes. Binding of transcription factors, including NF-κß, STAT3, and CDX2, to appropriate promoter sites of these genes supports the differential expression shown with chromatin immunoprecipitation assays. Total histone deacetylase (HDAC), and specifically HDAC3, activities were markedly reduced with Zip14 ablation. Intestinal organoids derived from ΔIEC mice display TJ and cytokine gene dysregulation compared with control mice. Differential expression of specific genes was reversed with zinc supplementation of the organoids. We conclude that zinc-dependent HDAC enzymes acquire zinc ions via Zip14-mediated transport and that intestinal integrity is controlled in part through epigenetic modifications.NEW & NOTEWORTHY We show that enterocyte-specific ablation of zinc transporter Zip14 (Slc39a14) results in selective dysbiosis and differential expression of tight junction proteins, claudin 1 and 2, and specific cytokines associated with intestinal inflammation. HDAC activity and zinc uptake are reduced with Zip14 ablation. Using intestinal organoids, the expression defects of claudin 1 and 2 are resolved through zinc supplementation. These novel results suggest that zinc, an essential micronutrient, influences gene expression through epigenetic mechanisms.

Relationship between honeybee nutrition and their microbial communities.

The microbiota and the functional genes actively involved in the process of breakdown and utilization of pollen grains in beebread and bee guts are not yet understood. The aim of this work was to assess the diversity and community structure of bacteria and archaea in Africanized honeybee guts and beebread as well as to predict the genes involved in the microbial bioprocessing of pollen using state of the art 'post-light' based sequencing technology. A total of 11 bacterial phyla were found within bee guts and 10 bacterial phyla were found within beebread. Although the phylum level comparison shows most phyla in common, a deeper phylogenetic analysis showed greater variation of taxonomic composition. The families Enterobacteriaceae, Ricketsiaceae, Spiroplasmataceae and Bacillaceae, were the main groups responsible for the specificity of the bee gut while the main families responsible for the specificity of the beebread were Neisseriaceae, Flavobacteriaceae, Acetobacteraceae and Lactobacillaceae. In terms of microbial community structure, the analysis showed that the communities from the two environments were quite different from each other with only 7 % of species-level taxa shared between bee gut and beebread. The results indicated the presence of a highly specialized and well-adapted microbiota within each bee gut and beebread. The beebread community included a greater relative abundance of genes related to amino acid, carbohydrate, and lipid metabolism, suggesting that pollen biodegradation predominantly occurs in the beebread. These results suggests a complex and important relationship between honeybee nutrition and their microbial communities.

Soil pH determines microbial diversity and composition in the park grass experiment.

The Park Grass experiment (PGE) in the UK has been ongoing since 1856. Its purpose is to study the response of biological communities to the long-term treatments and associated changes in soil parameters, particularly soil pH. In this study, soil samples were collected across pH gradient (pH 3.6-7) and a range of fertilizers (nitrogen as ammonium sulfate, nitrogen as sodium nitrate, phosphorous) to evaluate the effects nutrients have on soil parameters and microbial community structure. Illumina 16S ribosomal RNA (rRNA) amplicon sequencing was used to determine the relative abundances and diversity of bacterial and archaeal taxa. Relationships between treatments, measured soil parameters, and microbial communities were evaluated. Clostridium, Bacteroides, Bradyrhizobium, Mycobacterium, Ruminococcus, Paenibacillus, and Rhodoplanes were the most abundant genera found at the PGE. The main soil parameter that determined microbial composition, diversity, and biomass in the PGE soil was pH. The most probable mechanism of the pH impact on microbial community may include mediation of nutrient availability in the soil. Addition of nitrogen to the PGE plots as ammonium sulfate decreases soil pH through increased nitrification, which causes buildup of soil carbon, and hence increases C/N ratio. Plant species richness and plant productivity did not reveal significant relationships with microbial diversity; however, plant species richness was positively correlated with soil microbial biomass. Plants responded to the nitrogen treatments with an increase in productivity and a decrease in the species richness.