Human milk oligosaccharides in Chinese lactating mothers and relationship with allergy development in offspring

BACKGROUND

The health benefits of breastfeeding are partly contributed by human milk oligosaccharides (HMOs), but there is limited data on breast milk (BM) HMO composition in Chinese.

OBJECTIVE

This study investigated the association between early-life HMO intake and allergy occurrence in Chinese children.

METHODS

103 healthy Chinese pregnant women regardless of allergy history were recruited into this birth cohort. Their babies were followed until 24 months old. Concentrations of 2'-fucosyllactose (2'-FL), lacto-N-neotetraose (LNnT), -sialyllactose (3'-SL) and 6'-sialyllactose (6'-SL) in BM collected at 1-month postpartum were measured by liquid chromatography-mass spectrometry. The associations between these HMOs and allergy occurrence by 24 months were analyzed by multivariate regression analyses.

RESULTS

Twenty-nine percent and 19% of participants had eczema at 12 and 24 months old respectively. Eighty BM samples were analyzed, with 2'-FL being the most abundant HMO (median 1447 ppm, interquartile range [IQR] 291-1906 ppm), and median (IQR) levels of LNnT, 6'-SL and 3'-SL in ppm were 738 (580-950), 20.5 (12.7-38.8) and 23.0 (17.8-27.6) respectively. Participants with eczema by 24 months consumed BM with higher 2'-FL concentration at 1-month (P = 0.008), and also lower 6'-SL concentration in exclusively breastfed infants (P = 0.012) but higher 6'-SL concentration for those with mixed feeding at 1 month (P = 0.043). Food allergic children at 12 months consumed BM with higher 2'-FL concentrations at 1 month (P = 0.048).

CONCLUSIONS

BM 2'-FL concentration is higher in children who develops eczema by 24 months and food allergy during infancy. The relationship for 6'-SL is divergent depending on mode of feeding in infants.

Study of structure-activity correlation in destruxins, a class of cyclodepsipeptides possessing suppressive effect on the generation of hepatitis B virus surface antigen in human hepatoma cells

A new destruxin [destruxin E2 chlorohydrin] was isolated from the culture medium of Metarrhizium anisopliae and its structure was determined by NMR spectroscopy and mass spectrometry. As compared with other destruxins, the new destruxin showed a lower suppressive activity on the production of hepatitis B virus surface antigen in human hepatoma Hep3B cells. NMR study coupled with molecular modeling by computer graphics has revealed that the hydrophobicity nature of the convex surface characteristic of all destruxin molecules plays an important role in their biological activity.

Conformational study of two linear hexapeptides by two-dimensional NMR and computer-simulated modeling: implication for peptide cyclization in solution

Two linear peptides, D-leucyl-L-prolyl-L-isoleucyl-L-valyl-L-alanyl-beta-alanine (I) and D-leucyl-L-prolyl-L-isoleucyl-L-valyl-N-methyl-L-alanyl-beta-alanine (II), whose sequences were designed from protodestruxin and desmethyldestruxin B by replacing D-leucic acid with D-leucine, two cyclic hexadepsipeptides with insecticidal and immunodepressant activities, have been found to be cyclized in unusually high yields (>85%). In order to gain insight into the conformation and the relative flexibility of different constituent residues in these linear peptides, we have applied various techniques of 2D-NMR spectroscopy coupled with dynamic simulated annealing by computer modeling to establish the solution conformations of these two linear peptides. Based on the derived structures, it is found that the distances between N- and C-terminal residues of both peptides are short enough to facilitate the cyclization, thus collaborating the observation of favorable cyclization yields for both linear peptides.

Structure and immunological properties of thymosin beta 9 Met, a new analog of thymosin beta 4 isolated from porcine thymus

During the course for the studies of thymosin beta 4 and prothymosin alpha from porcine thymus, a new analog of thymosin beta 4 has been identified. This peptide consists of 41 amino acid residues. The amino terminus is blocked by an acetyl group as revealed by fast atom bombardment mass spectrometric analysis. Amino acid sequence studies disclosed that this peptide is identical to bovine thymosin beta 9 except that leucine at position 6 in beta 9 is substituted by methionine. Thus, this new peptide has been termed thymosin beta 9 Met. The recoveries of beta 9 Met, beta 4, and prothymosin alpha in porcine tissues have been determined (in micrograms/g tissue) as follows: thymus (43, 85, 133); spleen (68, 203, 37); liver (10, 31, 27); heart (1.5, 10, 0); kidney (5, 51, 37); brain (0.8, 31, 5). Biologically, thymosin beta 9 Met was found to be more active than beta 4 in enhancing gamma-interferon production in cord blood lymphocytes. However, beta 4 appeared to stimulate higher amounts of interleukin 2 and tumor necrotic factor. The significance for the coexistence of two homologous peptides with similar functions in the thymus and a number of other organs is not clear, and deserves further investigation.