Background: Numerous studies have evaluated protein and amino acid levels in human milk. However, research in this area has been limited by small sample sizes and study populations with little ethnic or racial diversity.
Objective: Evaluate the protein and amino acid composition of mature (≥30 days) human milk samples collected from a large, multinational study using highly standardized methods for sample collection, storage, and analysis.
Design: Using a single, centralized laboratory, human milk samples from 220 women (30-188 days postpartum) from nine countries were analyzed for amino acid composition using Waters AccQ-Tag high-performance liquid chromatography and total nitrogen content using the LECO FP-528 nitrogen analyzer. Total protein was calculated as total nitrogen×6.25. True protein, which includes protein, free amino acids, and peptides, was calculated from the total amino acids.
Results: Mean total protein from individual countries (standard deviation [SD]) ranged from 1,133 (125.5) to 1,366 (341.4) mg/dL; the mean across all countries (SD) was 1,192 (200.9) mg/dL. Total protein, true protein, and amino acid composition were not significantly different across countries except Chile, which had higher total and true protein. Amino acid profiles (percent of total amino acids) did not differ across countries. Total and true protein concentrations and 16 of 18 amino acid concentrations declined with the stage of lactation.
Conclusions: Total protein, true protein, and individual amino acid concentrations in human milk steadily decline from 30 to 151 days of lactation, and are significantly higher in the second month of lactation compared with the following 4 months. There is a high level of consistency in the protein content and amino acid composition of human milk across geographic locations. The size and diversity of the study population and highly standardized procedures for the collection, storage, and analysis of human milk support the validity and broad application of these findings.
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http://dx.doi.org/10.3402/fnr.v60.31042 | DOI Listing |
Curr Med Chem
January 2025
Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia.
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Acta Crystallogr A Found Adv
March 2025
Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-11 Mustuno, Atsuta-ku, Nagoya, 456-8587, Japan.
Due to the short de Broglie wavelength of electrons compared with X-rays, the curvature of their Ewald sphere is low, and individual electron diffraction patterns are nearly flat in reciprocal space. As a result, a reliable unit-cell determination from a set of randomly oriented electron diffraction patterns, an essential step in serial electron diffraction, becomes a non-trivial task. Here we describe an algorithm for unit-cell determination from a set of independent electron diffraction patterns, as implemented in the program PIEP (Program for Interpreting Electron diffraction Patterns), written in the early 1990s.
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January 2025
Plant Biochemistry and Physiology, Bielefeld University, Bielefeld, Germany.
The network of antagonistic, neutral, and synergistic interactions between (micro)organisms has moved into the focus of current research, since in agriculture, this knowledge can help to develop efficient biocontrol strategies. Applying the nematophagous fungus as biocontrol agent to manage the root-knot nematode is a highly promising strategy. To gain new insight into the systemic response of plants to a plant-parasitic nematode and a nematophagous fungus, was inoculated with and/or and subjected to transcriptome and metabolome analysis of leaves.
View Article and Find Full Text PDFChem Sci
January 2025
School of Chemistry, University of Glasgow Joseph Black Building, University Avenue Glasgow G12 8QQ UK
To overcome the limitations of using large extrinsic chromophores for biological imaging, fluorescent unnatural α-amino acids have been widely adopted as intrinsic peptidic probes. Although various classes have been successfully utilised for imaging applications, novel amino acid probes readily prepared through operationally simple synthetic methodology are still required. Here, we report a new approach for the synthesis of unnatural α-amino acids a one-pot process involving activation and palladium-catalysed arylation of tyrosine.
View Article and Find Full Text PDFPvHCt, a 23-amino acid long, histidine-rich peptide derived from shrimp, becomes strongly antimicrobial upon Cu(ii) ion binding. We describe Zn(ii) and Cu(ii) complexes of this peptide, aiming to understand how metal binding and structure correlates to biological activity. Using NMR, UV-vis, CD and FTIR spectroscopies, along with cyclic voltammetry, potentiometry, and DFT calculations, we demonstrate that Cu(ii) binds to the central and C-terminal regions of the peptide, inducing significant structural changes.
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