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 .
Project description:We got insights into the B. bifidum PRL2010 genes whose expression resulted to be affected when bacterial cells were cultivated on kefir and kefiran as the unique carbon source. In order to exploit the transcriptome of PRL2010 grown on kefir and hefiran we performed global transcription profiling using PRL2010 microarrays hybridized with cDNA from the RNA samples of B. bifidum PRL2010 cultivated on these substrates. We isolated mRNA from B. bifidum PRL2010 cells collected from a culture of kefir grains and from PRL2010 cultivated on MRS plus kefiran at upon 12 hours following inoculation. Microarray analysis was performed with an oligonucleotide array based on the B. bifidum PRL2010 genome: a total of 8,130 oligonucleotide probes of 60bp in length were designed on 1707 ORFs using eArray5.0 (Agilent Technologies). 5 Oligos were designed for each gene on a 4x44k Agilent Microarrays(Agilent Technologies, Santa Clara, CA, USA). Replicates were distributed on the chip at random, non-adjacent positions.
