Project description:The terminal compartments of Streptomyces are less prone to transcription than the rest of the chromosome. Indeed, the expression of the highly variable regions enriched in those compartments is generally conditional and often requires an empirical approach to characterize the inducing conditions. For instance, in the context of identifying adequate antibiotic production conditions, an OSMAC (“One Strain Many Compounds”) approach is frequently implemented, based on strain cultivation in different environmental conditions (composition of the medium, growth time, temperature, co-cultures, etc.). Likewise, to find the expression conditions of a complete prophage of Streptomyces ambofaciens ATCC 23877 (named 'Samy' phage/prophage), we conducted a similar approach by analyzing the transcriptomes in five solid media (HT, SAF, ONA, MMM, MMM+NAG). The terminal compartments of Streptomyces are less prone to transcription than the rest of the chromosome. Indeed, the expression of the highly variable regions enriched in those compartments is generally conditional and often requires an empirical approach to characterize the inducing conditions. For instance, in the context of identifying adequate antibiotic production conditions, an OSMAC (“One Strain Many Compounds”) approach is frequently implemented, based on strain cultivation in different environmental conditions (composition of the medium, growth time, temperature, co-cultures, etc.). Likewise, to find the expression conditions of a complete prophage of Streptomyces ambofaciens ATCC 23877 (named 'Samy' phage/prophage), we conducted a similar approach by analyzing the transcriptomes in five solid media (HT, SAF, ONA, MMM, MMM+NAG).
Project description:Streptomyces bingchenggensis is a soil bacterium that produces a family of macrolide antibiotics, milbemycins, which is commercially important in crop protection, human and veterinary medicine. After the complete genome sequence, and annotation, for further development of our gene expression approach to biosynthesis, we have employed whole genome microarray expression profiling as a discovery platform to obtain improved specificity and sensitivity of gene expression analysis, allowing a global and at the same time detailed picture of how gene clusters for secondary metabolism are modulated. In the result, we confirmed the expression mil and nan gene cluster, furthermore, pks3, pks5 and nrps7, nrps8 also showed significant gene expression, but no obvious products detected. In Streptomyces bingchenggensis, there are also corresponding genes belonging to Defense mechanisms, which is much more than other Streptomyces, for the resistance of own metabolites and dealing with complex environmental factors.
Project description:The objective was to analyze the differential expression between the wild strain and the Streptomyces clavuligerus ΔclaR::aac mutant
Project description:The aim of this work was to unveil the molecular mechanisms by which Streptomyces respond to a ROS intracellular imbalance and the effect of such response on the biosynthesis of secondary metabolites. The study was focused on the industrial actinomycete S. natalensis ATCC 27448 producer of the polyene pimaricin - an antifungal agent widely used in the food industry and promising for antiviral activity and stimulation of immune response.
Project description:Two component sensor-response regulator systems (TCSs) are very common in the genomes of the Streptomyces species that have been fully sequenced to date. It has been suggested that this large number is an evolutionary response to the variable environment that Streptomyces encounter in soil. Notwithstanding this, TCSs are also more common in the sequenced genomes of other Actinomycetales when these are compared to the genomes of most other eubacteria. In this study, we have used DNA/DNA genome microarray analysis to compare fourteen Streptomyces species and one closely related genus to Streptomyces coelicolor in order to identify a core group of such systems. This core group is compared to the syntenous and non-syntenous TCSs present in the genome sequences of other Actinomycetales in order to separate the systems into those present in Actinomycetales in general, the Streptomyces specific systems and the species specific systems. Horizontal transfer does not seem to play a very important role in the evolution of the TCS complement analyzed in this study. However, cognate pairs do not necessarily seem to evolve at the same pace, which may indicate the evolutionary responses to environmental variation may be reflected differently in sequence changes within the two components of the TCSs. The overall analysis allowed subclassification of the orphan TCSs and the TCS cognate pairs and identification of possible targets for further study using gene knockouts, gene overexpression, reporter genes and yeast two hybrid analysis.
