Project description:Camel milk is widely characterized with regard to caseins and whey proteins. However, in camelids, close to nothing is known about the Milk Fat Globule Membrane (MFGM), the membrane surrounding fat globules in milk. The purpose of this study was thus to identify MFGM proteins from Camelus dromedarius milk. Major MFGM proteins (namely, fatty acid synthase, xanthine oxidase, butyrophilin, lactadherin, and adipophilin) already evidenced in cow milk were identified in camel milk using mass spectrometry. In addition, a 1D-LC-MS/MS approach led us to identify 322 functional groups of proteins associated with the camel Milk Fat Globule Membrane. We hope that these findings will contribute to a better characterization of camel milk and to an improved understanding of lipid droplet formation in the mammary epithelial cell.
Project description:The one-humped Arabian camel (Camelus dromedarius) is the most important livestock animal in arid and semi-arid regions and continues to provide basic necessities to millions of people. In the current context of global warming, there is renewed interest in the adaptive mechanisms that enable camelids to survive in arid conditions. Recent investigations described genomic signatures that revealed evolutionary adaptations to desert environments. We now present a comprehensive catalogue of the transcriptomes and proteomes of the dromedary kidney and describe how the gene expression profiles of Differentially Expressed Genes (DEGs) are modulated as a consequence of chronic dehydration and subsequent acute rehydration. We performed RNAseq and quantification of peptides in samples from 15 dromedaries (5 controls, 5 dehydrated and 5 rehydrated). Gene Ontology analyses suggested an enrichment of the cholesterol biosynthetic process and an overrepresentation of categories related to ion transmembrane transport in the camel kidney, and RTN analyses confirmed alterations in the transcriptional machinery involved in cholesterol synthesis. These data were validated by RT-qPCR. Based on our hypothesis of a role for cholesterol during dehydration, we identified DEGs with roles in the countercurrent multiplication process which are affected by changes in the level of cholesterol. Thus, we further validated differentially expressed genes with known roles in water conservation which are affected by changes in cholesterol levels. Our datasets suggest that suppression of cholesterol biosynthesis may facilitate water retention in the kidney by indirectly facilitating the AQP2-mediated water reabsorption.
