Prevalence and genomic characterization of clinical Escherichia coli strains that harbor the plasmid-borne tet(X4) gene in China.

The tigecycline resistance gene tet(X4) has been widely reported in animals and animal products in some Asian countries including China in recent years but only sporadically detected in human. In this study, we investigated the prevalence and genetic features of tet(X4)-positive clinical E. coli strains. A total of 462 fecal samples were collected from patients in four hospitals located in four provinces in China in 2023. Nine tet(X4)-positive E. coli strains were isolated and subjected to characterization of their genetic and phenotypic features by performing antimicrobial susceptibility test, whole-genome sequencing, bioinformatic and phylogenetic analysis. The majority of the test strains were found to exhibit resistance to multiple antimicrobial agents including tigecycline but remained susceptible to colistin and meropenem. A total of seven different sequence types (STs) and an unknown ST type were identified among the nine tet(X4)-positive strains. Notably, the tet(X4) gene in six out of these nine tet(X4)-positive E. coli strains was located in a IncFIA-HI1A-HI1B hybrid plasmid, which was an tet(X4)-bearing epidemic plasmid responsible for dissemination of the tet(X4) gene in China. Furthermore, the tet(X4) gene in four out of nine tet(X4)-positive E. coli isolates could be successfully transferred to E. coli EC600 through conjugation. In conclusion, this study characterized the epidemic tet(X4)-bearing plasmids and tet(X4)-associated genetic environment in clinical E. coli strains, suggested the importance of continuous surveillance of such tet(X4)-bearing plasmids to control the increasingly widespread dissemination of tigecycline-resistant pathogens in clinical settings in China.

High-entropy engineering with regulated defect structure and electron interaction tuning active sites for trifunctional electrocatalysis.

High-entropy alloy nanoparticles (HEANs) possessing regulated defect structure and electron interaction exhibit a guideline for constructing multifunctional catalysts. However, the microstructure-activity relationship between active sites of HEANs for multifunctional electrocatalysts is rarely reported. In this work, HEANs distributed on multi-walled carbon nanotubes (HEAN/CNT) are prepared by Joule heating as an example to explain the mechanism of trifunctional electrocatalysis for oxygen reduction, oxygen evolution, and hydrogen evolution reaction. HEAN/CNT excels with unmatched stability, maintaining a 0.8V voltage window for 220 h in zinc-air batteries. Even after 20 h of water electrolysis, its performance remains undiminished, highlighting exceptional endurance and reliability. Moreover, the intrinsic characteristics of the defect structure and electron interaction for HEAN/CNT are investigated in detail. The electrocatalytic mechanism of trifunctional electrocatalysis of HEAN/CNT under different conditions is identified by in situ monitoring and theoretical calculation. Meanwhile, the electron interaction and adaptive regulation of active sites in the trifunctional electrocatalysis of HEANs were further verified by density functional theory. These findings could provide unique ideas for designing inexpensive multifunctional high-entropy electrocatalysts.

Impact of Processing Methods on the Distribution of Mineral Elements in Goat Milk Fractions.

Milk and dairy products are excellent sources of mineral elements, including Ca, P, Mg, Na, K and Zn. The purpose of this study was to determine the effect of non-thermal (homogenization) and thermal (heat treatment) treatments on the distribution of mineral elements in 4 milk fractions: fat, casein, whey protein, and aqueous phase. The study results revealed that the distribution of mineral elements (such as Mg and Fe) in fat fractions is extremely low, while significant mineral elements such as Ca, Zn, Fe, and Cu are mostly dispersed in casein fractions. For non-treated goat milk, Mo is the only element identified in the whey protein fraction, while K and Na are mostly found in the aqueous phase. Mineral element concentrations in fat (K, Zn, etc.) and casein fraction (Fe, Mo, etc.) increased dramatically after homogenization. Homogenization greatly decreased the concentration of mineral elements in the whey protein fraction (Ca, Na, etc.) and aqueous phase (Fe, Cu, etc.). After heat treatment, the element content in the fat fraction and casein fraction increased greatly when compared with raw milk, such as Cu and Mg in the fat fraction, Na and Cu in the whey protein fraction, the concentration of components such as Mg and Na in casein fraction increased considerably. On the other hand, after homogenization, Zn in the aqueous phase decreased substantially, whereas Fe increased significantly. Therefore, both homogenization and heat treatment have an effect on the mineral element distribution in goat milk fractions.

Identification of pasteurized mare milk and powder adulteration with bovine milk using quantitative proteomics and metabolomics approaches.

Adulteration in dairy products presents food safety challenges, driven by economic factors. Processing may change specific biomarkers, thus affecting their effectiveness in detection. In this study, proteomics and metabolomics approaches were to investigate the detection of bovine milk (BM) constituents adulteration in pasteurized mare milk (PMM) and mare milk powder (MMP). Several bovine proteins and metabolites were identified, with their abundances in PMM and MMP increasing upon addition of BM. Proteins like osteopontin (OPN) and serotransferrin (TF) detected adulteration down to 1 % in PMM, whereas these proteins in MMP were utilized to identify 10 % adulteration. Biotin and N6-Me-adenosine were effective in detecting adulteration in PMM as low as 10 % and 1 % respectively, while in MMP, their detection limits extend down to 0.1 %. These findings offer insights for authenticating mare milk products and underscore the influence of processing methods on biomarker levels, stressing the need to consider these effects in milk product authentication.

Value of the NF-κB signalling pathway and the DNA repair gene PARP1 in predicting distant metastasis after breast cancer surgery.

The DNA repair gene PARP1 and NF-κB signalling pathway affect the metastasis of breast cancer by influencing the drug resistance of cancer cells. Therefore, this study focused on the value of the DNA repair gene PARP1 and NF-κB pathway proteins in predicting the postoperative metastasis of breast cancer. A nested case‒control study was performed. Immunohistochemical methods were used to detect the expression of these genes in patients. ROC curves were used to analyse the predictive effect of these factors on distant metastasis. The COX model was used to evaluate the effects of PARP1 and TNF-α on distant metastasis. The results showed that the expression levels of PARP1, IKKß, p50, p65 and TNF-α were significantly increased in the metastasis group (P < 0.001). PARP1 was correlated with IKKß, p50, p65 and TNF-α proteins (P < 0.001). There was a correlation between IKKß, p50, p65 and TNF-α proteins (P < 0.001). ROC curve analysis showed that immunohistochemical scores for PARP1 of > 6, IKKß of > 4, p65 of > 4, p50 of > 2, and TNF-α of > 4 had value in predicting distant metastasis (SePARP1 = 78.35%, SpPARP1 = 79.38%, AUCPARP1 = 0.843; Sep50 = 64.95%, Spp50 = 70.10%, AUCp50 = 0.709; SeTNF-α = 60.82%, SpTNF-α = 69.07%, AUCTNF-α = 0.6884). Cox regression analysis showed that high expression levels of PARP1 and TNF-α were a risk factor for distant metastasis after breast cancer surgery (RRPARP1 = 4.092, 95% CI 2.475-6.766, P < 0.001; RRTNF-α = 1.825, 95% CI 1.189-2.799, P = 0.006). Taken together, PARP1 > 6, p50 > 2, and TNF-α > 4 have a certain value in predicting breast cancer metastasis, and the predictive value is better when they are combined for diagnosis (Secombine = 97.94%, Spcombine = 71.13%).

Constructing Cooperative Interface via Bi-Functional COF for Facilitating the Sulfur Conversion and Li+ Dynamics.

Lithium-sulfur (Li-S) batteries stand out for their high theoretical specific capacity and cost-effectiveness. However, the practical implementation of Li-S batteries is hindered by issues such as the shuttle effect, tardy redox kinetics, and dendrite growth. Herein, an appealingly designed covalent organic framework (COF) with bi-functional active sites of cyanide groups and polysulfide chains (COF-CN-S) is developed as cooperative functional promoters to simultaneously address dendrites and shuttle effect issues. Combining in situ techniques and theoretical calculations, it can be demonstrated that the unique chemical architecture of COF-CN-S is capable of performing the following functions: 1) The COF-CN-S delivers significantly enhanced Li+ transport capability due to abundant ion-hopping sites (cyano-groups); 2) it functions as a selective ion sieve by regulating the dynamic behavior of polysulfide anions and Li+ , thus inhibiting shuttle effect and dendrite growth; 3) by acting as a redox mediator, the COF-CN-S can effectively control the electrochemical behavior of polysulfides and enhance their conversion kinetics. Based on the above advantages, the COF-CN-S endows Li-S batteries with excellent performance. This study highlights the significance of interface modification and offers novel insights into the rational design of organic materials in the Li-S realm.

Elevated programmed cell death-1 protein/ligand (PD-1/PD-L1) and variants are associated with susceptibility to multiple myeloma: a case-control study in the Chinese cohort.

Multiple myeloma (MM) is a malignant disorder characterised by progressive immune dysregulation. The importance of programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) in MM has been documented in various populations, but studies have been limited to the Chinese cohort. In the present study, we examined the role of PD-1/PDL-1 in large cohorts of Chinese patients with MM and healthy controls to reveal a possible association with MM. Three hundred thirty-four MM patients and 202 healthy age-sex-matched subjects were enrolled in the present study. Serum levels of PD-1 and PD-L1 were quantified by ELISA. Percentages of T cells (CD4+ and CD8+ T cells) expressing PD-1 receptor were assessed by flow cytometry. Variants in PD-L1 (rs4143815) and PD-1 gene (rs2227981, rs2227982, rs7421861 and rs11568821) were genotyped by PCR-RFLP method. Patients with multiple myeloma had higher levels of PD-1 and PDL-1 than healthy controls, indicating an important role for programmed cell death protein-1 and its ligand in the pathogenesis of MM. T cells expressing PD-1 receptors were also significantly higher in MM patients than in controls. Mutants for PD-L1 (rs4143815) and PD-1 (rs2227982 and rs7421861) polymorphisms were significantly more common in MM than in HC. Interestingly, PD-L1 (rs4143815) and PD-1 (rs2227982 and rs7421861) variants were linked to higher sPD-L1 and sPD-1 levels, respectively. PD-1/PD-L1 levels are significantly higher in MM patients and could be a promising biomarker for the disease. Variants of PD-L1 and PD-1 are linked to serum-soluble proteins and are associated with the development of MM.

Effect of lactation on the distribution of mineral elements in goat milk.

The distribution of mineral elements in milk is crucial for their absorption and utilization, however, there has been limited attention given to the status of mineral elements in goat milk. In this study, goat milk was collected at 4 lactation periods (1-3, 90, 150, 240 d) and separated into 4 fractions (fat, casein, whey, and aqueous phase). The concentrations of Mg, Ca, Na, K, Zn, Fe, Cu, Mn, Co, Ni, Mo, and Cr in 4 fractions were analyzed using an inductively coupled plasma emission spectrometer. Our findings reveal that Ca, Zn, Fe, Cu, Mn, and Cr exhibit the highest levels in casein, while Mo demonstrates the highest content in whey. Additionally, Mg, Na, K, and Ni display the highest concentrations in the aqueous phase. Specifically, the contents of Ca, Cu and Fe in casein decrease from 1-3 to 150 d of lactation but increase from 150 to 240 d of lactation. Furthermore, the content of Mg in the aqueous phase decreases from 1-3 to 90 d of lactation but increases from 90 to 240 d of lactation. The content of Na and K in the aqueous phase decreases from 1-3 to 150 d of lactation. Notably, the content of Mo in whey increases from 1-3 to 150 d of lactation and decreases from 150 to 240 d. Our research contributes to the advancement of understanding the bioavailability of mineral elements in goat milk.

Bioactive Functions of Lipids in the Milk Fat Globule Membrane: A Comprehensive Review.

The milk fat globule membrane (MFGM) is a complex tri-layer membrane that wraps droplets of lipids in milk. In recent years, it has attracted widespread attention due to its excellent bioactive functions and nutritional value. MFGM contains a diverse array of bioactive lipids, including cholesterol, phospholipids, and sphingolipids, which play pivotal roles in mediating the bioactivity of the MFGM. We sequentially summarize the main lipid types in the MFGM in this comprehensive review and outline the characterization methods used to employ them. In this comprehensive review, we sequentially describe the types of major lipids found in the MFGM and outline the characterization methods employed to study them. Additionally, we compare the structural disparities among glycerophospholipids, sphingolipids, and gangliosides, while introducing the formation of lipid rafts facilitated by cholesterol. The focus of this review revolves around an extensive evaluation of the current research on lipid isolates from the MFGM, as well as products containing MFGM lipids, with respect to their impact on human health. Notably, we emphasize the clinical trials encompassing a large number of participants. The summarized bioactive functions of MFGM lipids encompass the regulation of human growth and development, influence on intestinal health, inhibition of cholesterol absorption, enhancement of exercise capacity, and anticancer effects. By offering a comprehensive overview, the aim of this review is to provide valuable insights into the diverse biologically active functions exhibited by lipids in the MFGM.

Regulating the Lithium Ions' Local Coordination Environment through Designing a COF with Single Atomic Co Site to Achieve Dendrite-Free Lithium-Metal Batteries.

The detrimental growth of lithium dendrites and unstable solid electrolyte interphase (SEI) inhibit the practical application of lithium-metal batteries. Herein, atomically dispersed cobalt coordinate conjugated bipyridine-rich covalent organic framework (sp2 c-COF) is explored as an artificial SEI on the surface of the Li-metal anode to resolve these issues. The single Co atoms confined in the structure of COF enhance the number of active sites and promote electron transfer to the COF. The synergistic effects of the Co─N coordination and strong electron-withdrawing cyano-group can adsorb the electron from the donor (Co) at a maximum and create an electron-rich environment, hence further regulating the Li+ local coordination environment and achieving uniform Li-nucleation behavior. Furthermore, in situ technology and density functional theory calculations reveal the mechanism of the sp2 c-COF-Co inducing Li uniform deposition and promoting Li+ rapid migration. Based on these advantages, the sp2 c-COF-Co modified Li anode exhibits a low Li-nucleation barrier of 8 mV, and excellent cycling stability of 6000 h.

Research Progress and Future Trends of Low Temperature Plasma Application in Food Industry: A Review.

Food nutrition, function, sensory quality and safety became major concerns to the food industry. As a novel technology application in food industry, low temperature plasma was commonly used in the sterilization of heat sensitive materials and is now widely used. This review provides a detailed study of the latest advancements and applications of plasma technology in the food industry, especially the sterilization field; influencing factors and the latest research progress in recent years are outlined and upgraded. It explores the parameters that influence its efficiency and effectiveness in the sterilization process. Further research trends include optimizing plasma parameters for different food types, investigating the effects on nutritional quality and sensory attributes, understanding microbial inactivation mechanisms, and developing efficient and scalable plasma-based sterilization systems. Additionally, there is growing interest in assessing the overall quality and safety of processed foods and evaluating the environmental sustainability of plasma technology. The present paper highlights recent developments and provides new perspectives for the application of low temperature plasma in various areas, especially sterilization field of the food industry. Low temperature plasma holds great promise for the food industry's sterilization needs. Further research and technological advancements are required to fully harness its potential and ensure safe implementation across various food sectors.

Identification markers of goat milk adulterated with bovine milk based on proteomics and metabolomics.

This study investigated the differences in proteins and metabolites from goat and bovine milk, and their mixtures, using data-independent-acquisition-based proteomics and metabolomics methods. In the skim milk, relative abundances of secretoglobin family 1D member (SCGB1D), polymeric immunoglobulin receptor, and glycosylation-dependent cell adhesion molecule 1 were increased, with an increase in the amount of 1-100 % bovine milk and served as markers at the 1 % adulteration level. In whey samples, ß-lactoglobulin and α-2-HS-glycoprotein could be used to detect adulteration at the 0.1 % adulteration level, and SCGB1D and zinc-alpha-2-glycoprotein at the 1 % level. The metabolites of uric acid and N-formylkynurenine could be used to detect bovine milk at adulteration levels as low as 1 % based on variable importance at a projection value of > 1.0 and P-value of < 0.05. Our findings suggest novel markers of SCGB1D, uric acid, and N-formylkynurenine that can help to facilitate assessments of goat milk authenticity.

Slightly acidic electrolyzed water as a novel thawing media combined with ultrasound for improving thawed mutton quality, nutrients and microstructure.

The effects of ultrasound-assisted slightly acidic electrolyzed water thawing (UET), air thawing (AT), water thawing (WT) and microwave thawing (MT) on the quality, nutrients and microstructure were investigated. The UET treatment did not affect the lightness (L*) but reduced the redness (a*) and yellowness (b*) of the mutton. The UET treatment could better maintain the textural properties. The UET group had a higher immobilized water and lower free water, which was closer to the state of the control group. The UET treatment not only effectively inhibited the lipid oxidation but also reduced the loss of nutrients, especially minerals. The microstructure of the UET group was smoother and more complete, and the muscle fibers did not show significant breakage. In conclusion, UET treatment could better maintain the quality, nutrients and microstructure of thawed mutton. Therefore, UET could be regarded as a potential thawing method for application in the processing of meat products.

Changes in milk fat globule physical properties and milk fatty acid composition throughout the lactation cycle of Laoshan goat.

The objective of this study was to investigate the effect of lactation stage on the physical properties of milk fat globules (MFGs) and profiles of milk fatty acids (FAs) of milk from Laoshan dairy goats. Goat colostrum and milk samples were collected on days 1, 3, 30, 90, 150, and 240 postpartum. Milk fat content was found to significantly decrease during the first 90 d of lactation and increase thereafter as lactation progressed (P < 0.01). Average area particle size and volume particle size of MFGs showed trends similar to those of the milk fat content of goat milk with the extension of lactation, and the lowest levels were 2.39 µm and 3.97 µm on day 90, respectively (P < 0.01). The zeta-potential of MFGs significantly increased before 30 d of lactation, with a slight drop on day 90. It increased thereafter and tended to stabilize in the late stages of lactation (P < 0.01). The content of several saturated fatty acids (SFAs) (C10:0-C16:0) in early lactation, especially in colostrum, was lower than that in other stages of lactation (P < 0.05). Branched-chain fatty acids of the iso and anteiso series, including C13:0 anteiso, C15:0 anteiso, and C15:0 iso, were observed at high contents in mid-lactation goat milk (P < 0.01). As lactation progressed (3 d to 240 d), the content of SFAs significantly increased (P < 0.01), while the content of monounsaturated fatty acids and polyunsaturated fatty acids significantly decreased (P < 0.05). Furthermore, the content of C18:0 significantly increased during the first 30 d of lactation and decreased thereafter as lactation progressed (P < 0.01). Our results indicated that lactation stage has a pronounced effect on the physical properties of MFGs and the FA profiles of goat milk.

The composition and physical properties of milk fat affect the quality and sensory properties of dairy products. However, changes in the physical properties of milk fat globules (MFGs) and profiles of milk fatty acids (FAs) of goat milk throughout the lactation period remain unclear. In the current study, we found that milk fat content and particle size of goat MFG decreased significantly during 90 d of lactation and increased thereafter as lactation progressed. The content of saturated FAs significantly increased, while that of monounsaturated FAs and polyunsaturated FAs significantly decreased from colostrum to late-lactation milk. The characteristics of goat MFGs and milk FAs were affected by the lactation period, which may provide valuable insights into the utilization of MFGs from dairy goats.

Ultrasound combined with slightly acidic electrolyzed water thawing of mutton: Effects on physicochemical properties, oxidation and structure of myofibrillar protein.

The effects of air thawing (AT), water immersion thawing (WT), microwave thawing (MT) and ultrasound combined with slightly acidic electrolyzed water thawing (UST) on the myofibrillar protein (MP) properties (surface hydrophobicity, solubility, turbidity, particle size and zeta potential), protein oxidation (carbonyl content and sulfhydryl content) and structure (primary, secondary and tertiary) of frozen mutton were investigated in comparison with fresh mutton (FM). The solubility and turbidity results showed that the MP properties were significantly improved in the UST treatment. UST treatment could effectively reduce the MP aggregation and enhance the stability, which was similar to the FM. In addition, UST treatment could effectively inhibit protein oxidation during thawing as well. The primary structure of MP was not damaged by the thawing methods. UST treatment could reduce the damage to MP secondary and tertiary structure during the thawing process compared to other thawing methods. Overall, the UST treatment had a positive influence in maintaining the MP properties by inhibiting protein oxidation and protecting protein structure.

Comparative analysis of changes in whey proteins of goat milk throughout the lactation cycle using quantitative proteomics.

The composition and content of goat milk proteins are affected by many factors and have been extensively studied. However, variation in whey protein composition in goat milk throughout the lactation cycle has not been clarified. In the current study, 15 dairy goats were selected, and milk samples were collected at 1, 3, 30, 90, 150, and 240 d after delivery. Whey proteins were separated and digested and then identified using data-independent acquisition (DIA) and data-dependent acquisition proteomics approaches. Protein profiles identified using DIA were consistent with those of the data-dependent acquisition proteomics approach according to clustering and principal component analyses. Significant differences in the abundance of 238 proteins around the lactation cycle were identified using the DIA approach. Developmental changes of the whey proteome corresponding to lactation stage were revealed: plasminogen, α-2-macroglobulin, and fibronectin levels decreased from d 1 to 240, whereas polymeric immunoglobulin receptor, nucleobindin 2, fatty acid-binding protein 3, and lactoperoxidase increased from d 1 to 240. Protein-protein interaction analysis showed that fibronectin with a higher degree of connectivity is a central node. The findings are of great significance to better understanding the potential role of specific proteins and the mechanism of protein biosynthesis or intercellular transport in the mammary glands related to the physiological changes of dairy goats.

Identification of mare milk adulteration with cow milk by liquid chromatography-high resolution mass spectrometry based on proteomics and metabolomics approaches.

Mare milk(MM)production is lower than that of cow milk (CM), making it a premium product. Unfortunately, sellers adulterate MM with cheap CM to unscrupulously gain more profits. This study aimed to analyze MM adulteration with CM using proteomics and metabolomics. Using univariate and multivariate statistical analysis, the relative abundances of certain proteins of caseins and secretoglobin family 1D member were found to be higher with a higher CM admixture percentage. In addition, several metabolites, such as orotic and 4-aminonicotinic acids, increased in the mare-cow milk mixture with an increased CM percentage. Accordingly, these proteins and metabolites distinguished MM adulterated with CM at levels as low as 1 %.These findings can serve as the basis for clarifying the differences at the proteome and metabolome in milk from minor dairy animals and ensure milk authenticity.

Effects of ultrasound-assisted slightly acidic electrolyzed water thawing on myofibrillar protein conformation and gel properties of chicken breasts.

The effects of air thawing, water thawing, slightly acidic electrolyzed water thawing, ultrasound-assisted water thawing (WUT) and ultrasound-assisted slightly acidic electrolyzed water thawing (EUT) on the myofibrillar protein conformation and gel quality of chicken breasts were investigated. In the EUT group, protein solubility was higher (52.43%) than other thawing groups, and particle size was 24.57% smaller than the control group. Gel of EUT and WUT groups had stronger elasticities than the control group. Gel whiteness level was not significantly different between the EUT and control group. Gel water holding capacity of the EUT group was 9.07% greater than the control group. Gel water distributions and mobilities of the EUT and WUT groups were closer to the control group. The gel of the EUT group had a compact and homogeneous network. In conclusion, EUT treatment effectively reduced conformation disruption and improved gel properties, which was conducive to producing gel products.

Developmental changes in proteins of casein micelles in goat milk using data-independent acquisition-based proteomics methods during the lactation cycle.

Casein micelles (CM) play an important role in milk secretion, stability, and processing. The composition and content of milk proteins are affected by physiological factors, which have been widely investigated. However, the variation in CM proteins in goat milk throughout the lactation cycle has yet to be fully clarified. In the current study, milk samples were collected at d 1, 3, 30, 90, 150, and 240 of lactation from 15 dairy goats. The size of CM was determined using laser light scattering, and CM proteins were separated, digested, and identified using data-independent acquisition (DIA) and data-dependent acquisition (DDA)-based proteomics approaches. According to clustering and principal component analysis, protein profiles identified using DIA were similar to those identified using the DDA approach. Significant differences in the abundance of 115 proteins during the lactation cycle were identified using the DIA approach. Developmental changes in the CM proteome corresponding to lactation stages were revealed: levels of lecithin cholesterol acyltransferase, folate receptor α, and prominin 2 increased from 1 to 240 d, whereas levels of growth/differentiation factor 8, peptidoglycan-recognition protein, and 45 kDa calcium-binding protein decreased in the same period. In addition, lipoprotein lipase, glycoprotein IIIb, and α-lactalbumin levels increased from 1 to 90 d and then decreased to 240 d, which is consistent with the change in CM size. Protein-protein interaction analysis showed that fibronectin, albumin, and apolipoprotein E interacted more with other proteins at the central node. These findings indicate that changes in the CM proteome during lactation could be related to requirements of newborn development, as well as mammary gland development, and may thus contribute to elucidating the physical and chemical properties of CM.