Effect of H2O2-assisted ultrasonic bath on the degradation and physicochemical properties of pectin.

The effects of H2O2-assisted ultrasonic bath degradation technology on pectin were investigated. The degradation efficiency with different pectin concentrations, H2O2 concentrations, ultrasonic power, and ultrasonic time was analyzed. The results showed that pectin concentration was negatively correlated with the degradation efficiency of pectin, while, H2O2 concentration, ultrasonic power, and ultrasonic time were positive correlated with the degradation efficiency. Besides, the apparent viscosity and viscoelasticity of the degraded pectin decreased significantly. The antioxidant activity increased after the H2O2-assisted ultrasonic bath treatment. The results of FTIR, NMR, laser particle size, SEM, XRD, and AFM analysis indicated that the degradation treatment did not destroy the main structure of pectin. The average particle size and crystallinity of pectin decreased. The degree of aggregation and the height of the molecular chain decreased significantly. In conclusion, the H2O2-assisted ultrasonic bath degradation technique could effectively degrade pectin. This study provided a comprehensive analysis of the degradation of pectin under H2O2-assisted ultrasonic bath, which will be beneficial to further develop H2O2-assisted ultrasonic bath techniques for pectin degradation.

Characterization and comparison of whey N-glycoproteomes from human and bovine colostrum and mature milk.

Milk glycoproteins are crucial nutrients with a variety of functions. However, whey N-glycoproteomes in human and bovine milks have not been characterized during lactation. Herein, using lectin enrichment and liquid chromatography tandem mass spectrometry, 68, 58, 100, and 98 N-glycoproteins were identified in human colostrum and mature milk as well as bovine colostrum and mature milk whey. Gene Ontology and KEGG pathway analyses were used to elucidate the biological functions of whey N-glycoproteins in human and bovine colostrum and mature milks. Whey N-glycoproteomes differed dramatically between human and bovine milks and across lactation stages. The conserved and specific whey N-glycoproteins in all four sample types were also determined. Our results improve understanding of the properties and biological functions of whey N-glycoproteins in human and bovine milk and colostra, and provide insight into the potential application of some N-glycoproteins in infant formulae at different stages of development.

Quantitative analysis of amino acids in human and bovine colostrum milk samples through iTRAQ labeling.

BACKGROUND: The types and quantity of proteins vary widely between bovine and human milk, with corresponding differences in free and hydrolytic amino acids. In this study, the free and hydrolytic amino acids of bovine and human colostrum were for the first time qualitatively and quantitatively determined using isobaric tags for relative and absolute quantification technology combined with liquid chromatography tandem mass spectrometry detection. RESULTS: Total free amino acid content was 0.32 g L-1 and 0.63 g L-1 in bovine and human colostrum respectively, with free amino acid content in human colostrum twice that of bovine colostrum. However, total hydrolytic amino acid content was 4.2 g L-1 and 2.2 g L-1 in bovine and human colostrum respectively. We found that the hydrolytic amino acid content in bovine colostrum was higher than that in human colostrum; however, the amount of free amino acids and the overall amino acid content in human colostrum were respectively substantially higher and more varied than in bovine colostrum. CONCLUSION: Our findings revealed differences between bovine and human colostrum, with these data providing the basis for further research into amino acid metabolomics and infant formula. © 2018 Society of Chemical Industry.

Comparative Analysis of Whey N-Glycoproteins in Human Colostrum and Mature Milk Using Quantitative Glycoproteomics.

Glycosylation is a ubiquitous post-translational protein modification that plays a substantial role in various processes. However, whey glycoproteins in human milk have not been completely profiled. Herein, we used quantitative glycoproteomics to quantify whey N-glycosylation sites and their alteration in human milk during lactation; 110 N-glycosylation sites on 63 proteins and 91 N-glycosylation sites on 53 proteins were quantified in colostrum and mature milk whey, respectively. Among these, 68 glycosylation sites on 38 proteins were differentially expressed in human colostrum and mature milk whey. These differentially expressed N-glycoproteins were highly enriched in "localization", "extracellular region part", and "modified amino acid binding" according to gene ontology annotation and mainly involved in complement and coagulation cascades pathway. These results shed light on the glycosylation sites, composition and biological functions of whey N-glycoproteins in human colostrum and mature milk, and provide substantial insight into the role of protein glycosylation during infant development.

Rhodamine B induces long nucleoplasmic bridges and other nuclear anomalies in Allium cepa root tip cells.

The cytogenetic toxicity of rhodamine B on root tip cells of Allium cepa was investigated. A. cepa were cultured in water (negative control), 10 ppm methyl methanesulfonate (positive control), and three concentrations of rhodamine B (200, 100, and 50 ppm) for 7 days. Rhodamine B inhibited mitotic activity; increased nuclear anomalies, including micronuclei, nuclear buds, and bridged nuclei; and induced oxidative stress in A. cepa root tissues. Furthermore, a substantial amount of long nucleoplasmic bridges were entangled together, and some nuclei were simultaneously linked to several other nuclei and to nuclear buds with nucleoplasmic bridges in rhodamine B-treated cells. In conclusion, rhodamine B induced cytogenetic effects in A. cepa root tip cells, which suggests that the A. cepa root is an ideal model system for detecting cellular interactions.