Ontology highlight
ABSTRACT:
PROVIDER: PRJNA847025 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Experimental evolution is a powerful approach to study how ecological forces shape microbial genotypes and phenotypes, but to date strains were predominantly adapted to conditions specific to laboratory environments. The lactic acid bacterium Lactococcus lactis naturally occurs on plants and in the dairy environment and it is generally believed, that dairy strains originate from the plant niche. Here we investigated the adaptive process from the plant to the dairy niche and show that during the experimental evolution of a L. lactis plant isolate in milk, several mutations are selected that affect amino acid metabolism and transport. Three independently evolved strains were characterized by whole genome re-sequencing, revealing 4 to 28 mutational changes in the individual strains. Two of the adapted strains showed clearly increased acidification rates and yields in milk, and contained three identical point mutations. Transcriptome profiling and extensive phenotyping of the wild-type plant isolate compared to the evolved mutants, and a "natural" dairy isolate confirmed that major physiological changes associated with improved performance in the dairy environment relate to nitrogen metabolism. The deletion of a putative transposable element led to a significant decrease of the mutation rate in two of the adapted strains. These results specify the adaptation of a L. lactis strain isolated from mung bean sprouts to growth in milk and they demonstrate that niche-specific adaptations found in environmental microbes can be reproduced by experimental evolution.
2010-03-03 | GSE20373 | GEO
Project description:The intra sub-species diversity of six strains of Lactococcus lactis subsp. lactis was investigated at the genomic level and in terms of phenotypic and transcriptomic profiles in UF-cheese model. Six strains were isolated from various sources, but all are exhibiting a dairy phenotype. Our results showed that, the six strains exhibited small phenotypic differences since similar behaviour in terms of growth was obtained during cheese ripening while only different acidification capability was detected. Even if all strains displayed high genomic similarities, sharing a high core genome of almost two thousands genes, the expression of this core genome directly in the cheese matrix revealed major strain-specific differences. This strains with the same dairy origin. Strains were cultured on skimmed raw milk ultrafiltration (UF) retentate. The UF retentate was pre-incubated overnight at 4 °C, then 45 minutes at 50 °C and homogenized during 1.5 minutes at 24 000 rpm with an ultra-turax (Imlab, France). After addition of rennet (0.3 µl ml-1), 400 g UF retentate was inoculated at 2 106 CFU/g with L. lactis subsp. lactis strains. After incubation for 8 hours at 30 °C, the cheeses were transferred at 12° C until 7 days for ripening simulation. At least three independent cultures of the six strains were performed. Total RNA was extracted from cells grown 24 hours in UF-cheese and radiolabelled cDNA were prepared and hybridized on nylon arrays. 1948 amplicons specific of Lactococcus lactis IL1403 genes were spotted twice on the array. 3 independent repetitions were performed.
2012-09-07 | E-GEOD-23987 | biostudies-arrayexpress
Project description:Experimental evolution is a powerful approach to study how ecological forces shape microbial genotypes and phenotypes, but to date strains were predominantly adapted to conditions specific to laboratory environments. The lactic acid bacterium Lactococcus lactis naturally occurs on plants and in the dairy environment and it is generally believed, that dairy strains originate from the plant niche. Here we investigated the adaptive process from the plant to the dairy niche and show that during the experimental evolution of a L. lactis plant isolate in milk, several mutations are selected that affect amino acid metabolism and transport. Three independently evolved strains were characterized by whole genome re-sequencing, revealing 4 to 28 mutational changes in the individual strains. Two of the adapted strains showed clearly increased acidification rates and yields in milk, and contained three identical point mutations. Transcriptome profiling and extensive phenotyping of the wild-type plant isolate compared to the evolved mutants, and a "natural" dairy isolate confirmed that major physiological changes associated with improved performance in the dairy environment relate to nitrogen metabolism. The deletion of a putative transposable element led to a significant decrease of the mutation rate in two of the adapted strains. These results specify the adaptation of a L. lactis strain isolated from mung bean sprouts to growth in milk and they demonstrate that niche-specific adaptations found in environmental microbes can be reproduced by experimental evolution. Multiple loop design with 12 samples and 16 dual label arrays. Each sample is hybrdized at least on two different arrays and with both dyes.
2010-06-24 | E-GEOD-20373 | biostudies-arrayexpress
Project description:The intra sub-species diversity of six strains of Lactococcus lactis subsp. lactis was investigated at the genomic level and in terms of phenotypic and transcriptomic profiles in UF-cheese model. Six strains were isolated from various sources, but all are exhibiting a dairy phenotype. Our results showed that, the six strains exhibited small phenotypic differences since similar behaviour in terms of growth was obtained during cheese ripening while only different acidification capability was detected. Even if all strains displayed high genomic similarities, sharing a high core genome of almost two thousands genes, the expression of this core genome directly in the cheese matrix revealed major strain-specific differences. This strains with the same dairy origin.
2012-09-07 | GSE23990 | GEO
Project description:The intra sub-species diversity of six strains of Lactococcus lactis subsp. lactis was investigated at the genomic level and in terms of phenotypic and transcriptomic profiles in UF-cheese model. Six strains were isolated from various sources, but all are exhibiting a dairy phenotype. Our results showed that, the six strains exhibited small phenotypic differences since similar behaviour in terms of growth was obtained during cheese ripening while only different acidification capability was detected. Even if all strains displayed high genomic similarities, sharing a high core genome of almost two thousands genes, the expression of this core genome directly in the cheese matrix revealed major strain-specific differences. This strains with the same dairy origin.
2012-09-07 | GSE23987 | GEO
Project description:The intra sub-species diversity of six strains of Lactococcus lactis subsp. lactis was investigated at the genomic level and in terms of phenotypic and transcriptomic profiles in UF-cheese model. Six strains were isolated from various sources, but all are exhibiting a dairy phenotype. Our results showed that, the six strains exhibited small phenotypic differences since similar behaviour in terms of growth was obtained during cheese ripening while only different acidification capability was detected. Even if all strains displayed high genomic similarities, sharing a high core genome of almost two thousands genes, the expression of this core genome directly in the cheese matrix revealed major strain-specific differences. This strains with the same dairy origin. Strains were cultured on M17. At least three independent cultures of the six strains were performed. Genomic DNA was extracted from cells grown overnight on M17 and radiolabelled cDNA were prepared and hybridized on nylon arrays. 1948 amplicons specific of Lactococcus lactis IL1403 genes were spotted twice on the array. 3 independent repetitions were performed.
2012-09-07 | E-GEOD-23990 | biostudies-arrayexpress
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
2008-12-31 | GSE12638 | GEO
Project description:Milk and dairy products are an essential food and an economic resource in many countries. Milk component synthesis and secretion by the mammary gland involve expression of a large number of genes whose nutritional regulation remains poorly defined. We aim at understanding the genomic influence on milk quality and synthesis by comparing two sheep breeds, with different milking attitude, Sarda and Gentile di Puglia, using sheep-specific microarray technology. From sheep ESTs deposited at NCBI, we generated the first annotated microarray developed for sheep with a covering of most of the genome.
2009-11-30 | GSE18619 | GEO