G. Leiserowitz, K. Kim, S. Miyamoto, R. Ruhaak, S. Hua, L. Dimapasoc, C. Williams, C. Lebrilla, “Glycomics analysis as a potential diagnostic test for ovarian cancer“, Gynecologic Oncology, Volume 130, Issue 1, July 2013, Page e21
Ruiz-Moyano, S., S. M. Totten, D. Garrido, J. T. Smilowitz, J. B. German, C. B. Lebrilla and D. A. Mills (2013). “Variation in consumption of human milk oligosaccharides by infant-gut associated strains of Bifidobacterium breve.” Appl Environ Microbiol.
Human milk contains a high concentration of complex oligosaccharides that influence the composition of the intestinal microbiota in breast-fed infants. Previous studies have indicated that select species such as Bifidobacterium longum subsp. infantis and B. bifidum can utilize human milk oligosaccharides (HMO) in vitro as the sole carbon source, while the relatively few B. longum subsp. longum and B. breve isolates tested appear less adapted to these substrates. Considering the high frequency at which B. breve is isolated from breast-fed infant feces, we postulated that some B. breve strains can more vigorously consume HMOs and thus are enriched in the breast-fed infant gastrointestinal tract. To examine this a number of B. breve isolates from breast-fed infant feces were characterized for the presence of different glycosyl hydrolases that participate in HMO utilization, as well as by their ability to grow on HMO or specific HMO species such as lacto-N-tetraose (LNT) and fucosyllactose. All B. breve strains showed a high growth on lacto-N-tetraose and lacto-N-neotetraose (LNnT), and, in general, growth on total HMO was moderate for most of the strains, with several strain differences. Growth and consumption of fucosylated HMO was strain-dependent, mostly in isolates possessing a Glycosyl Hydrolase family 29 alpha-fucosidase. Glycoprofiling of the spent supernatant after HMO fermentation by select strains revealed that all B. breve can utilize sialylated HMO to a certain extent, especially sialyl-lacto-N-tetraose. Interestingly, this specific oligosaccharide was depleted before neutral LNT by strain SC95. In aggregate, this work indicates that the HMO consumption phenotype in B. breve is variable, however specific strains display specific adaptations to these substrates enabling more vigorous consumption of fucosylated and sialylated HMO. These results provide a rationale for the predominance of this species in breast-fed infant feces, and contribute to a more accurate picture of the ecology of the developing infant intestinal microbiota.
De Leoz, M. L., C. B. Lebrilla and M. A. Underwood (2013). “Response to Letter to the Editor regarding “A quantitative and comprehensive method to analyze human milk oligosaccharide structures in the urine and feces of infants“.” Anal Bioanal Chem.