Assessing multiple factors affecting the gut microbiome structure of very preterm infants

The composition and diversity of the gut microbiota are essential for the health and development of the immune system of infants. However, there is limited information on factors that influence the gut microbiota of very preterm infants. In this study, we analyzed factors that affect the gut microbiota of very preterm infants. The stool samples from 64 very preterm infants with a gestational age less than 32 weeks were collected for 16S rRNA gene sequencing. The infants were divided according to the delivery mode, antibiotic use during pregnancy, and feeding methods. The abundance of Proteobacteria was high in both cesarean (92.7%) and spontaneous (55.5%) delivery groups and then shifted to Firmicutes after the first week of birth. In addition, Proteobacteria was also the dominant phylum of infant gut microbiome for mothers with antibiotic use, with more than 50% after the first week of birth. In comparison, the dominant phylum for mothers without antibiotic use was Firmicutes. Proteobacteria level was also high in breastfeeding and mixed-feeding groups, consisting of more than 90% of the community. By contrast, Proteobacteria was the dominant phylum at the first week of birth but then shifted to Firmicutes for the formula-fed group. The alterations of gut microbiota in infants can affect their health condition during growth. This study confirmed that the different feeding types, delivery modes, and use of antibiotics during pregnancy can significantly affect the composition of the gut microbiota of very preterm infants.

Short Tandem Repeats in plants: genomic distribution and function prediction

BACKGROUND: Short Tandem repeats (STRs) existed as popular elements in both eukaryotic and prokaryotic genomes. RESULTS: In this study, we analyzed the characteristics, distributions, and motif features of STRs within whole-genomes of 140 plant species. The results showed that STR density was negatively correlated with the genome size. Hexanucleotide repeat was the most abundant type of STRs. The distribution of algae shows a preference different from that of other plants. By analyzing GC contents of STRs and genome, it was concluded that STR motif was influenced by GC contents. Analysis of the long STRs in genome (length 1000 bp) found that dicots have the more long STRs. For STR types, di- and tri-nucleotide accounted for the highest proportion. Analyzing and designing long STRs in CDS (length 500 bp) was to verify the role of long STRs in Gossypium hirsutum TM-1 and Solanum tuberosum. By comparing the long STRs found in Fragaria x ananassa with other species, some evolutionary characteristics of the long STRs were obtained. CONCLUSIONS: We got the characteristics, distribution, and motif features of STRs in the whole genome of 140 plants and obtained some evolutionary characteristics of long STRs. The study provides useful insights into STR preference, characteristics, and distribution in plants.