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ABSTRACT:
PROVIDER: PRJNA526499 | ENA |
REPOSITORIES: ENA
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Project description:Lactobacillus helveticus is a rod-shaped lactic acid bacterium that is widely used in the manufacture of fermented dairy foods and for production of bioactive peptides from milk proteins. Although L. helveticus is commonly associated with milk environments, phylogenetic studies show it is closely related to an intestinal species, Lactobacillus acidophilus, which has been shown to impart probiotic health benefits to humans. This relationship has fueled a prevailing hypothesis that L. helveticus is a highly specialized derivative of L. acidophilus which has adapted to acidified whey. However, L. helveticus has also been sporadically recovered from non-dairy environments, which argues the species may not be as highly specialized as is widely believed. This study employed genome sequence analysis and comparative genome hybridizations to investigate genomic diversity among L. helveticus strains collected from cheese, whey, and whiskey malt, as well as commercial cultures used in manufacture of cheese or bioactive dairy foods. Results revealed considerable variability in gene content between some L. helveticus strains, and indicated the species should not be viewed as a strict dairy-niche specialist. In addition, comparative genomic analyses provided new insight on several industrially and ecologically important attributes of L. helveticus that may facilitate commercial strain selection.
2013-08-16 | GSE23660 | GEO
Project description:Lactobacillus helveticus is a rod-shaped lactic acid bacterium that is widely used in the manufacture of fermented dairy foods and for production of bioactive peptides from milk proteins. Although L. helveticus is commonly associated with milk environments, phylogenetic studies show it is closely related to an intestinal species, Lactobacillus acidophilus, which has been shown to impart probiotic health benefits to humans. This relationship has fueled a prevailing hypothesis that L. helveticus is a highly specialized derivative of L. acidophilus which has adapted to acidified whey. However, L. helveticus has also been sporadically recovered from non-dairy environments, which argues the species may not be as highly specialized as is widely believed. This study employed genome sequence analysis and comparative genome hybridizations to investigate genomic diversity among L. helveticus strains collected from cheese, whey, and whiskey malt, as well as commercial cultures used in manufacture of cheese or bioactive dairy foods. Results revealed considerable variability in gene content between some L. helveticus strains, and indicated the species should not be viewed as a strict dairy-niche specialist. In addition, comparative genomic analyses provided new insight on several industrially and ecologically important attributes of L. helveticus that may facilitate commercial strain selection. 42 samples were hybridized to the microarray chip, which contains probe sequences from L. helveticus CNRZ32. CNRZ32 was also hybridized and used as the reference sample. Data from the microarray was statistically analyzed using the R software. Samples were compared to the reference (CNRZ32) to investigate genome diversity amoung L. helveticus strains,
2013-08-16 | E-GEOD-23660 | biostudies-arrayexpress
Project description:Genomic rearrangement, often driven by insertion sequence (IS) elements, is one of the major processes in the evolution of prokaryotes. Sequence analysis of 16S rRNA of Lactobacillus helveticus, an organism that evolved in a dairy environment and Lactobacillus acidiophilus an organism that evolved associated with the gastrointestinal tract (GIT) demonstrated 98.4% identity suggesting that they divergently evolved from a common ancestor. Moreover, complete genome sequence analysis of both organisms has demonstrated a remarkable degree of gene synteny (75% homologous genes) despite the presence of an exceptionally high number and diversity of IS elements in the Lb. helveticus genome. Array based comparative genomic hybridization (aCGH) performed on nine strains of Lb. helveticus revealed sixteen clusters of open reading frames (ORFs) flanked by IS elements. Four of these ORFs are associated with restriction/modification which may have played a role in accelerated evolution of strains in a commercially intensive ecosystem undoubtedly challenged through successive phage attack. Furthermore, analysis of the IS-flanked clusters demonstrated that the most frequently encountered IS were also those most abundant in the genome (IS1201, ISL2, ISLhe1, ISLhe2, ISLhe65 and ISLhe63). These findings contribute to the overall viewpoint on a versatile character of IS elements and the role they may play in bacterial genome plasticity.
2009-06-12 | GSE16553 | GEO
Project description:Reannotation of Deinococcus deserti genome
2010-04-30 | PRD000139 | Pride
Project description:L. helveticus is used to modulate cheese flavor and as a starter organism in certain cheese varieties. Our group has compiled a draft (4x) sequence for the 2.4 Mb genome of an industrial strain L. helveticus CNRZ32. The primary aim was to investigate expression of 168 completely sequenced genes during growth in milk and MRS medium using microarrays. Oligonucleotide probes against each of the completely sequenced genes were compiled on maskless photolithography-based DNA microarrays. Additionally, the entire draft genome sequence was used to produce tiled microarrays where the non-interrupted sequence contigs were covered by consecutive 24-mer probes. Keywords: growth conditions response
2007-02-14 | GSE7005 | GEO