ABSTRACTBifidobacteria are a major microbial component of infant gut microbiota, which is believed to promote health benefits for the host and stimulate maturation of the immune system. Despite their perceived importance, very little is known about the natural development of and possible correlations between bifidobacteria in human populations. To address this knowledge gap, we analyzed stool samples from a randomly selected healthy cohort of 87 infants and their mothers with >90% of vaginal delivery and nearly 100% breast-feeding at 4 months. Fecal material was sampled during pregnancy, at 3 and 10 days, at 4 months, and at 1 and 2 years after birth. Stool samples were predicted to be rich in the speciesBifidobacterium adolescentis,B. bifidum,B. dentium,B. breve, andB. longum. Due to high variation, we did not identify a clear age-related structure at the individual level. Within the population as a whole, however, there were clear age-related successions. Negative correlations between theB. longumgroup andB. adolescentiswere detected in adults and in 1- and 2-year-old children, whereas negative correlations betweenB. longumandB. brevewere characteristic for newborns and 4-month-old infants. The highly structured age-related development of and correlation networks between bifidobacterial species during the first 2 years of life mirrors their different or competing nutritional requirements, which in turn may be associated with specific biological functions in the development of healthy gut.
Age-related Development of the Arrangement of Connective Tissue Fibers in the Lamina Propria of the Human Vocal Folds. Scanning Electron Microscopic Examination with Digestion Method.
