Assessment of the Conformation Stability and Glycosylation Heterogeneity of Lactoferrin by Native Mass Spectrometry.

Lactoferrin (LTF) has diverse biological activities and is widely used in functional foods and active additives. Nevertheless, evaluating the proteoform heterogeneity, conformational stability, and activity of LTF remains challenging during its production and storage processes. In this study, we describe the implementation of native mass spectrometry (nMS), glycoproteomics, and an antimicrobial activity assay to assess the quality of LTF. We systematically characterize the purity, glycosylation heterogeneity, conformation, and thermal stability of LTF samples from different sources and transient high-temperature treatments by using nMS and glycoproteomics. Meanwhile, the nMS peak intensity and antimicrobial activity of LTF samples after heat treatment decreased significantly, and the two values were positively correlated. The nMS results provide essential molecular insights into the conformational stability and glycosylation heterogeneity of different LTF samples. Our results underscore the great potential of nMS for LTF quality control and activity evaluation in industrial production.

Unraveling volatilomics profiles of milk products from diverse regions in China.

To distinguish Chinese milks from different regions, 13 milk samples were gathered from 13 regions of China in this study: Inner Mongolia (IM), Xinjiang (XJ), Hebei (HB), Shanghai (SH), Beijing (BJ), Sichuan (SC), Ningxia (NX), Henan (HN), Tianjin (TJ), Qinghai (QH), Yunnan (YN), Guangxi (GX), and Tibet (XZ). Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) combined with the electronic nose (E-nose) technology, was used to detect and analyze the volatile compounds in these milk samples. The qualitative and quantitative results identified 29 volatile chemicals, and we established a database of flavor profiles for the main milk-producing regions in China. E-nose analysis revealed variations in the odor of milk across different areas. Furthermore, results from partial least squares discriminant analysis (PLS-DA) and odor activity values (OAVs) suggested that seven volatile compounds: decane, 2-heptanone, 2-undecanone, 2-nonanone, 1-hexadecanol, 1-octen-3-ol, and (E)-2-nonenal, could be considered as key flavor compounds in Chinese milk products.

MicroRNA-221 may be involved in lipid metabolism in mammary epithelial cells.

Milk lipids, important for infant growth and development, are produced and secreted by mammary gland under the regulation of steroid hormones, growth factors, and microRNAs (miRNAs). miR-221 has been identified in milk and adipocytes and it plays important roles in regulating normal mammary epithelial hierarchy and breast cancer stem cells; however, its roles in lipid metabolism in mammary epithelial cells (MECs), the cells of lipid synthesis and secretion, are as yet unknown. Through overexpression or inhibition of miR-221 expression, we found that it regulated lipid metabolism in MECs and was expressed differentially at various stages during murine mammary gland development. Inhibition of miR-221 expression increased lipid content in MECs through elevation of the lipid synthesis enzyme FASN, while overexpression of miR-221 reduced MEC lipid content. Moreover, the steroid hormones estradiol and progesterone decreased miR-221 expression with a subsequent increase in lipid formation in MECs. The expression of miR-221 was lower during lactation, which suggests that it may be involved in milk production. Therefore, miR-221 might be a useful target for influencing milk lipid production.

miR-15b negatively correlates with lipid metabolism in mammary epithelial cells.

Mammary epithelial cells are regulated by steroid hormones, growth factors, and even microRNAs. miR-15b has been found to regulate lipid metabolism in adipocytes; however, its effects on lipid metabolism in mammary epithelial cells, the cells of lipid synthesis and secretion, are as yet unknown. The main purpose of this investigation was to explore the effect of miR-15b on lipid metabolism in mammary epithelial cells, along with the underlying mechanisms. miR-15b was overexpressed or inhibited by miRNA mimics or inhibitors; subsequently, lipid formation in mammary epithelial cells, and proteins related to lipid metabolism, were investigated. Through overexpression or inhibition of miR-15b expression, the current investigation found that miR-15b downregulates lipid metabolism in mammary epithelial cells and is expressed differentially at various stages of mouse and goat mammary gland development. Inhibition of miR-15b expression increased lipid content in mammary epithelial cells through elevation of the lipid synthesis enzyme fatty acid synthetase (FASN), and overexpression of miR-15b reduced lipid content in mammary epithelial cells with decreasing levels of FASN. Moreover, the steroid hormones estradiol and progesterone decreased miR-15b expression with a subsequent increase in lipid formation in mammary epithelial cells. The expression of miR-15b was lower during lactation and negatively correlated with lipid synthesis proteins, which suggests that it may be involved in lipid synthesis and milk production. miR-15b might be a useful target for altering lipid production and milk yield.

MicroRNA-126 participates in lipid metabolism in mammary epithelial cells.

Lipids are a major component of milk and are important for infant growth and development. MicroRNA-126 (miR-126) has previously been observed in mammary glands and adipocytes and is known to be involved in lipid metabolism during the process of atherosclerosis. However, it remains unknown whether miR-126 also participates in lipid metabolism in mammary luminal epithelial cells (MECs). In the current investigation, miR-126-3p inhibition stimulated lipid synthesis in MECs in part through increasing levels of the lipid synthesis enzymes FASN, ACSL1, and Insig1. Overexpression of miR-126-3p decreased lipid content in MECs with a reduction in FASN and Insig1. Furthermore, the expression of miR-126-3p was diminished by the steroid hormones estradiol and progesterone with a subsequent elevation of lipid formation in MECs. We also noted that miR-126-3p was expressed differentially at various stages of murine mammary gland development, exhibiting a negative correlation with FASN. Together these findings suggest that miR-126-3 might be involved in lipid metabolism in mammary gland.

A phylo-functional core of gut microbiota in healthy young Chinese cohorts across lifestyles, geography and ethnicities.

Structural profiling of healthy human gut microbiota across heterogeneous populations is necessary for benchmarking and characterizing the potential ecosystem services provided by particular gut symbionts for maintaining the health of their hosts. Here we performed a large structural survey of fecal microbiota in 314 healthy young adults, covering 20 rural and urban cohorts from 7 ethnic groups living in 9 provinces throughout China. Canonical analysis of unweighted UniFrac principal coordinates clustered the subjects mainly by their ethnicities/geography and less so by lifestyles. Nine predominant genera, all of which are known to contain short-chain fatty acid producers, co-occurred in all individuals and collectively represented nearly half of the total sequences. Interestingly, species-level compositional profiles within these nine genera still discriminated the subjects according to their ethnicities/geography and lifestyles. Therefore, a phylogenetically diverse core of gut microbiota at the genus level may be commonly shared by distinctive healthy populations as functionally indispensable ecosystem service providers for the hosts.

[Studies on carcass and meat quality performance of crossbred pigs with graded proportions of Laiwu Black genes].

Sixty pigs, including pure Laiwu Black (LL), pure Large Yorkshire (YY), 1/2 Laiwu (Ymale x Lfemale), 3/4 Laiwu (Lmale x YLfemale) and 1/4 Laiwu (Ymale x YLfemale), were housed in groups with the same diet until 90 kg for slaughter. The objectives were to investigate the effects of graded proportions of Laiwu Black genes on carcass and meat quality performance. Results indicated that different consanguinity had significant effect on carcass weight, carcass length (CL), ham percentage (HP) and backfat thickness (BT) (P<0.05), and had highly significant effect on eye muscle area (EMA) and lean percentage (LP) (P<0.01). Furthermore, CL, HP, EMA and LP tended to increased gradually, but BT tended to decreased gradually as Laiwu Black genes decreased. For meat quality properties, different consanguinity had significant effect on meat color, marbling score, dry matter and crude protein content of muscles (P<0.05), and had highly significant effect on water loss, drip loss and intramuscular fat content of muscles (P<0.01). Compared with the muscle of Large Yorkshire, that of Laiwu Black and its crossbred pigs were bright red in meat color, high in water holding capacity and abundant in intramuscular fat. Results implied that to give attention to both quantity and quality, Laiwu Black surely has usable precious value in superior pig production. Commercial crossbred pigs should have about 1/4 of Laiwu Black genes.