Project description:This study examines the proteolytic activity of the kefir grains (a combination of bacteria and yeast) on bovine milk proteins. SDS-PAGE analysis reveals substantial digestion of milk proteins by the kefir grains in comparison with control samples. Mass spectrometric analysis reveals that the kefir microorganisms released 609 new peptide fragments and significantly altered the abundance of around 1,500 peptides compared to the controls. These kefir-digested peptides derived from 55 milk proteins. We show that kefir contains 25 previously identified functional peptides with actions including antihypertensive, antimicrobial, opioid and anti-oxidative .
2016-05-09 | PXD001826 | Pride
Project description:Metagenomic analysis of kefir fortified with anthocyanin
| PRJNA841283 | ENA
Project description:Kefir grain and milk kefir metagenome
Project description:In this study, we applied a proteomics strategy to identify peptides present in sheep milk kefir fermented at different times. We aimed to understand changes in the digestion pattern of milk proteins as well as to identify potential bioactive peptides.
Project description:There is little information regarding the allergen content of milk feeds in the preterm population. Previous studies have evaluated specific proteins/peptides via ELISA, but no studies have performed a broad analysis of the allergenic peptide content and protease activity of milk feeds in this population. Preterm infants spend a critical window of time for immune development in the Newborn Intensive Care Unit (NICU), and may receive fortified donor milk, maternal milk or formula feeds via nasogastric tube or bottle instead of fresh breastmilk via breastfeeding.
Project description:Kefir is a milk fermented by microorganisms with probiotic potential. Its consumption is associated with several beneficial effects, from antibacterial, healing, antioxidant, anti-inflammatory, anti-allergic, plasma glucose and cholesterol control to antitumor and antihypertensive activities. Despite its great potential, little is known about the bioactive molecules responsible for these actions. Therefore, the present project aims to perform the proteomic study of Kefir and its grain used for the milk fermentation aiming to identify the bioactive peptides, in particular those peptides with action in the cardiovascular system.
Project description:<p>Microbial communities often undergo intricate compositional changes yet also maintain stable coexistence of diverse species. The mechanisms underlying long-term coexistence remain unclear, as system-wide studies have been largely limited to engineered communities, ex situ adapted cultures, or synthetic assemblies. Here we show how kefir, a natural milk-fermenting community of prokaryotes and yeasts, realises stable coexistence through spatiotemporal orchestration of species and metabolite dynamics. During milk fermentation, kefir grains (a polysaccharide matrix synthesized by kefir microbes) grow in mass but remain unchanged in composition. In contrast, the milk is colonized in a sequential manner in which early members open metabolic niches for followers. Through metabolomics and large-scale mapping of inter-species interactions, we show how microbes poorly suited for milk survive in, and even dominate the community, through metabolic cooperation and uneven partitioning between grain and milk. Overall, our findings reveal how inter-species interactions partitioned in space and time lead to stable coexistence.</p><p><br></p><p><strong>Linked metabolomics studies:</strong></p><p><a href='https://www.ebi.ac.uk/metabolights/MTBLS1829' rel='noopener noreferrer' target='_blank'>MTBLS1829</a> Kefir fermentation curve (FIA-MS)</p><p><a href='https://www.ebi.ac.uk/metabolights/MTBLS1830' rel='noopener noreferrer' target='_blank'>MTBLS1830</a> Interaction between the kefir isolates Lactococcus lactis and Acetobacter fabarum (GC-MS)</p><p><br></p><p><strong>Linked cross omic data:</strong></p><p>Genomes of isolated kefir species are available in the <a href='https://www.ncbi.nlm.nih.gov/' rel='noopener noreferrer' target='_blank'>NCBI database</a> under the accession: PRJNA375758 (bioproject ID: 375758).</p><p>Metatranscriptomic sequencing reads can be accessed from <a href='www.ebi.ac.uk/ena' rel='noopener noreferrer' target='_blank'>ENA</a> under the project id PRJEB37001.</p><p>Genome-scale metabolic models for kefir bacteria can be found at github.com/cdanielmachado/kefir_models.</p>
Project description:Over the course of milk digestion, native milk proteases and infant digestive proteases fragment intact proteins into peptides with potential bioactivity. This study investigated the release of peptides over three hours of gastric digestion in 14 preterm infant sample sets. The peptide content was extracted and analyzed from milk and gastric samples via Orbitrap tandem mass spectrometry. The relative ion intensity (abundance) and count of peptides in each sample were compared over time and between infants fed milk fortified with bovine milk fortifier and infants fed unfortified milk. Bioactivity of the identified peptides was predicted by sequence homology to known bioactive milk peptides. Both total and bioactive peptide abundance and count continuously increased over three hours of gastric digestion. After accounting for infant weight, length, and post-conceptual age, fortification of milk limited the release of peptides from human milk proteins. Peptides that survived further gastric digestion after their initial release were structurally more similar to bioactive peptides than non-surviving peptides. This work is the first to provide a comprehensive profile of milk peptides released during gastric digestion over time, which is an essential step in determining which peptides are most likely to be biologically relevant in the infant.
