Project description:This SuperSeries is composed of the following subset Series: GSE23987: Transcriptomic profiles of six strains of Lactococcus lactis in ultrafiltration-cheese model GSE23990: Comparative genome hybridization profiles of six strains of Lactococcus lactis Refer to individual Series
Project description:Compare the physiological state between static, aerobic, and respiratory growth of Lactococcus lactis subsp. lactis CHCC2862 using whole genome transcriptomes. NOTE: the biological replicate array GSM243206 is dye-swapped relative to GSM202337 (unlike the two other biological replicate arrays GSM243203 and GSM24205). Keywords: Physiological response to aerobic and respiratory growth relative to static.
Project description:The stringent response was defined in Lactococcus lactis through transcript profiling after the addition of a chemical inductor, the norvaline. Gene expression was measured in the exponential growth phase (reference sample) and at 1.6 h after norvaline addition. Four hundred and sixty one differentially expressed genes were identified and constituted the stringent response regulon. Keywords: stress response, time course Stringent response was imposed through norvaline addition during the growth of Lactococcus lactis IL1403 under controlled conditions (30 °C, pH 6.6, nitrogen atmosphere). Cell samples were harvested in exponential phase and 1.6 h after norvaline addition. Total RNA was extracted from these samples and radiolabelled cDNA were prepared and hybridized on nylon arrays. 2053 amplicons specific of Lactococcus lactis IL1403 genes were spotted twice on the array. The 2 time-points were analyzed simultaneously and 3 independent repetitions were performed.
Project description:Pangenome arrays contain DNA oligomers targeting several sequenced reference genomes from the same species. In microbiology these can be employed to investigate the often high genetic variability within a species by comparative genome hybridization (CGH). The biological interpretation of pangenome CGH data depends on the ability to compare strains at a functional level, particularly by comparing the presence or absence of orthologous genes. Due to the high genetic variability, available genotype-calling algorithms can not be applied to pangenome CGH data. Therefore, we have developed the algorithm PanCGH that incorporates orthology information about genes to predict the presence or absence of orthologous genes in a query organism using CGH arrays that target the genomes of sequenced representatives of a group of microorganisms. PanCGH was tested and applied in the analysis of genetic diversity among 39 Lactococcus lactis strains from three different subspecies (lactis, cremoris, hordniae) and isolated from two different niches (dairy and plant). Clustering of these strains using the presence/absence data of gene orthologs revealed a clear separation between different subspecies and reflected the niche of the strains. Keywords: CGH, CGH analysis, orthology, Lactococcus lactis
Project description:Gene expression in Lactococcus lactis MG1363 was compared to that of L. lactis MG1363 â??guaA in rich GM17 medium. One condition design comparison of two strains
