Physiology of consumption of human milk oligosaccharides by infant gut-associated bifidobacteria.

The bifidogenic effect of human milk oligosaccharides (HMOs) has long been known, yet the precise mechanism underlying it remains unresolved. Recent studies show that some species/subspecies of Bifidobacterium are equipped with genetic and enzymatic sets dedicated to the utilization of HMOs, and consequently they can grow on HMOs; however, the ability to metabolize HMOs has not been directly linked to the actual metabolic behavior of the bacteria. In this report, we clarify the fate of each HMO during cultivation of infant gut-associated bifidobacteria. Bifidobacterium bifidum JCM1254, Bifidobacterium longum subsp. infantis JCM1222, Bifidobacterium longum subsp. longum JCM1217, and Bifidobacterium breve JCM1192 were selected for this purpose and were grown on HMO media containing a main neutral oligosaccharide fraction. The mono- and oligosaccharides in the spent media were labeled with 2-anthranilic acid, and their concentrations were determined at various incubation times using normal phase high performance liquid chromatography. The results reflect the metabolic abilities of the respective bifidobacteria. B. bifidum used secretory glycosidases to degrade HMOs, whereas B. longum subsp. infantis assimilated all HMOs by incorporating them in their intact forms. B. longum subsp. longum and B. breve consumed lacto-N-tetraose only. Interestingly, B. bifidum left degraded HMO metabolites outside of the cell even when the cells initiate vegetative growth, which indicates that the different species/subspecies can share the produced sugars. The predominance of type 1 chains in HMOs and the preferential use of type 1 HMO by infant gut-associated bifidobacteria suggest the coevolution of the bacteria with humans.

Quantitative determination of total L-carnitine in infant formula, follow-up formula, and raw materials by liquid chromatography with tandem mass spectrometry.

We developed a rapid and useful routine screening assay for total L-carnitine content in various infant formulas and materials by liquid chromatography coupled with a tandem mass spectrometric method (LC-MS/MS) and alkaline hydrolysis. For separation of L-carnitine, a multi-mode octadecylsilane (ODS) column was used that contained ODS ligands, anion ligands, and cation ligands to avoid using ion-pairing agents. The stable isotope L-carnitine-d3 (m/z 165 → 103/85) was used in electrospray MS/MS in the multiple reaction monitoring mode with the ion transitions of m/z 162 → 103/85 for detection and quantitation of L-carnitine. Alkaline hydrolysis of short/medium chain (C2 - C15) acyl-L-carnitines in infant formula was analyzed by LC with quadrupole time-of-flight mass spectrometry (QTOF-MS). The majority of short/medium chain acyl-L-carnitines were hydrolyzed to free L-carnitine. The overall standard deviations for L-carnitine in infant formula, follow-up formula and raw materials ranged from 2.1 to 4.0. The overall mean recoveries ranged from 90.2 to 94.2%.

Chemical characterization of milk oligosaccharides of an African lion (Panthera leo) and a clouded leopard (Neofelis nebulosa).

The Carnivora include the superfamilies Canoidea and Feloidea. In species of Canoidea other than the domestic dog, Canis lupus, the milk contains only traces of lactose and much larger concentrations of oligosaccharides. In this study, lactose was found to be the dominant saccharide in the milk or colostrum of two species of Feloidea, namely the African lion (Panthera leo) and the clouded leopard (Neofelis nebulosa). In addition to lactose, the following oligosaccharides were characterized in the milk of a lion; Neu5Gc(α2-3)Gal(ß1-4)Glc (3'-NGc-SL), Fuc(α1-2)Gal(ß1-4)Glc (2'-fucosyllactose) and GalNAc(α1-3)[Fuc(α1-2)]Gal(ß1-4)Glc (A-tetrasaccharide). The colostrum of a clouded leopard contained 3'-NGc-SL, Gal(α1-3)Gal(ß1-4)Glc (isoglobotriose) and A-tetrasaccharide. These oligosaccharides differ in some respects from those previously identified in another species of Feloidea, the spotted hyena (Crocuta crocuta). These milks contained 3'-NGc-SL and A-tetrasaccharide, while spotted hyena colostrum did not; however, it contained Neu5Ac(α2-3)Gal(ß1-4)Glc (3'-NAc-SL) and Gal(α1-3)[Fuc(α1-2)]Gal(ß1-4)Glc (B-tetrasaccharide).