BackgroundMilk exosomes are a rich source of microRNAs (miRNAs) that are protected from degradation. Ingestion of milk and subsequent absorption of miRNAs into recipient cells by endocytosis may play a role in the regulation of neonatal innate and adaptive immunity. In contrast, the miRNA content of milk exosomes may also be indicative of a lactating animal’s health; whereby, the presence or absence of specific miRNAs could serve as biomarkers for early detection of bacterial infection that can lead to mastitis. In the present study, we therefore analyzed and compared miRNA expression profiles of milk exosomes from four Holstein cows obtained during mid-lactation prior to and after infection (48 h) of the mammary gland with Staphylococcus aureus.MethodsMilk exosomes, purified from control and S. aureus infected cows, were extracted for RNA. Following preparation indexed libraries from both groups the samples were subjected to next generation sequencing.ResultsNext generation sequencing of eight, unpooled small RNA libraries derived from milk exosomes produced about 60.5 million high-quality, bovine-specific sequence reads for comparison of miRNA expression between treatments. Sequence identity analysis showed the miRNAs make up about 13 % of the average RNA content of these exosomes. Although 417 known bovine miRNAs were identified, miRNAs represented the least diverse class of RNA accounting for only 1 % of all unique sequences. The 20 most prevalent unique sequences within this class accounted for about 90 % of the total miRNA-associated reads across samples. Non-annotated, unique reads provided evidence for another 303 previously unknown bovine miRNAs. Expression analyses found 14 known bovine microRNAs significantly differed in frequency between exosomes from infected and control animals.ConclusionsOur survey of miRNA expression from uninfected milk exosomes and those produced in response to infection provides new and comprehensive information supporting a role for delivery into milk of specific miRNAs involved in immune response. In particular, bta-miR-142-5p, and −223 are potential biomarkers for early detection of bacterial infection of the mammary gland. Additionally, 22 mammary-expressed genes involved in regulation of host immune processes and response to inflammation were identified as potential binding targets of the differentially expressed miRNAs.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-2044-9) contains supplementary material, which is available to authorized users.

Background: There are at least 25 human selenoproteins, each characterized by the incorporation of selenium into the primary sequence as the amino acid selenocysteine. Since many selenoproteins have antioxidant properties, it is plausible that inter-individual differences in selenoprotein expression or activity could influence risk for a range of complex diseases, such as cancer, infectious diseases as well as deleterious responses to oxidative stressors like cigarette smoke. To capture the common genetic variants for 6 important selenoprotein genes (GPX1, GPX2, GPX3, GPX4, TXNRD1, and SEPP1) known to contribute to antioxidant host defenses, a resequence analysis was conducted across these genes with particular interest directed at the coding regions, intron-exon borders and flanking untranslated regions (UTR) for each gene in an 102 individual population representative of 4 major ethnic groups found within the United States.

We report here the near-complete genome sequences of 13 norovirus strains detected in stool samples from patients with acute gastroenteritis from Bangladesh, Ecuador, Guatemala, Peru, Nicaragua, and the United States that are classified into one existing (genotype II.22 [GII.22]), 3 novel (GII.23, GII.24 and GII.25), and 3 tentative novel (GII.NA1, GII.NA2, and GII.NA3) genotypes.

The complete coding sequences of three melon necrotic spot viruses (MNSVs) were obtained from viral metagenomics of stool samples from patients with acute gastroenteritis. These genomes were most similar to Spanish strains sequenced in 2003 and a novel MNSV watermelon strain in 2014.