| Milk is a complex biological fluid that provides primary nutrition for infants and newborn mammals.Bovine milk has been given much attention as an important human dietary and agro-economical product.Human breast milk is regarded as the best food for newborns.At present,the International Health Organization advocates that infants need to be breastfed six months ago.Therefore,the advanced proteomics technology was used for human colostrum,human mature milk,bovine colostrum,bovine mature milk analysis,to find differences in protein compositions,protein expression quantity,and key proteins.Casein compositions and structures in human and bovine milk were researched very thorough,so milk fat glouble membrane(MFGM),whey and exsomes in human and bovine milk across different lactation phases were deeply researched in this study.These results can provide comprehensive for infants' milk powder and functional dairy products.The system researches in this study could provide important information and potential direction for dairy industry.The main results in this study are as follows:1.In this paper,the MFGM protein was identified by mass spectrometry in human and bovine milk across different lactation phases.The results showed that 670 kinds of MFGM proteins were identified in bovine colostrum,488 kinds of MFGM proteins were identified in bovine mature milk,1078 kinds of MFGM proteins were identified in human colostrum,and 1545 kinds of MFGM proteins were identified in human mature milk.In these results,there were 270 specific expression proteins in human colostrum MFGM,291 specific expression proteins were found in human mature MFGM,160 kinds of specific expression proteins in bovine colostrum MFGM,46 specific expression proteins in bovine mature MFGM.Functional analysis of the identified MFGM protein revealed that MFGM in human and bovine milk across different lactation phases were not only different in protein compositions but also in biological functions.The intracellular proteolysis combined with LC-MS/MS were used to explore whey proteins in human and bovine milk across different lactation phases.The results showed that 539 whey proteins were identified in human colostrum,460 whey proteins were identified in human mature milk,291 whey proteins were identified in bovine colostrum,and 284 whey proteins in bovine mature milk.There were 104 specific expression proteins in human colostrum whey,and 40 specific expression proteins were found in human mature whey.There were 49 specific expression proteins in bovine colostrum whey,and 74 A specific expression proteins in bvoine mature whey.And the use of GO function and KEGG pathway analysis found that the protein compositions are quite different in the biological function and metabolic pathways.In this study,qualitative proteomics studies were carried out on human and bovine milk exosomes across different lactation phases.A total of 204 proteins were identified in the bovine colostrum exosomes,and 327 proteins were identified in human mature milk exosomes,and 327 proteins were identified in the human colostrum exosomes.In these identification results,there were 67 specific expression proteins in human colostrum exosomes,180 kinds of specific expression proteins in human mature exosomes,55 kinds of specific expression proteins in bovine colostrum exosomes,There are 16 exosomes in bovine mature exosomes.And the use of GO function annotation and KEGG pathway analysis found that the protein compositions in different lactation phases have a certain difference,biological function and metabolic pathways are also significantly different.2.To explore the different proteomics of human and bovine MFGM,MFGM proteins were separated from human and bovine colostrum and mature milk,and analyzed by the iTRAQ proteomic approach.A total of 411 proteins were recognized and quantified.Among these,232 kinds of differentially expressed proteins were identified.These differentially expressed proteins were analyzed based on multivariate analysis,gene ontology(GO)annotation and KEGG pathway.Biological processes involved in response to stimulus.Cellular components engaged in extracellular space.And identified 28 differentially expressed proteins were related to the immune system process,50 differentially expressed proteins were related to growth and development MFGM.Molecular functions touched upon protein binding.The KEGG pathway analysis showed several pathways,including regulation of actin cytoskeleton,focal adhesion.A total of 584 whey proteins in human and bovine colostrum and mature milk were identified and quantified by the isobaric tag for relative and absolute quantification(iTRAQ)proteomic method.The 424 differentially expressed whey proteins were identified and analyzed according to GO annotation,KEGG pathway,and multivariate statistical analysis.Biological processes principally involved biological regulation and response to stimulus.Major cellular components were extracellular region part.The most prevalent molecular function was protein binding.Twenty immune-related proteins and 13 proteins related to enzyme regulatory activity were differentially expressed in human and bovine milk.Differentially expressed whey proteins participated in many KEGG pathways,including major complement and coagulation cascades and in phagosomes.The advanced iTRAQ proteomic approach was used to analyze milk-derived exosomes in human and bovine colostrum and mature milk samples.A total of 920 milk exosome proteins were identified and quantified.Among these,575 differentially expressed exosome proteins(P<0.05)were found.Multivariate analysis,gene ontology(GO)annotation and the KEGGpathway were used to interpret the identified proteins.The major biological processes were mainly involved response to stimulus.Cellular components mainly engaged in intracellular.The most prevalent molecular function mainly touched upon binding.And 22 kinds of proteins associated with the immune system process were found,34 kinds of transport-related proteins.Milk exosome proteins participated in several KEGG pathways mainly containing protein processing in endoplasmic reticulum pathway. |
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