Project description:The Streptomyces lividans lsp gene encodes a type II signal peptidase (Lsp) that cleaves the type II leader peptides of lipoproteins. Transcriptional profiling of the bacterium depleted of the lsp gene mainly resulted in deactivation of the sigma U regulon, as well as in downregulation of genes involved in the biogenesis and function of ribosomes and genes encoding some major secretory proteins as determined by hybridisation of commercially available S. lividans genome-wide microarrays. Almost 50% of the dowregulated genes have been described as forming part of the stringent response in streptomycetes. The gene encoding the S. lividans extracellular foldase, the lipoprotein FkpA, is equally downregulated. Therefore, the deletion of lsp from the S. livdans genome temporarily triggers a cellular stress where the stringent response is, at least, partially induced.
Project description:The gene aml encoding alpha-amylase in Streptomyces lividans was cloned in the multicopy plasmid pIJ486, generating plasmid pAMI11. Plasmid pAMI11 and pIJ486 were propagated in S. lividans TK21 to obtain S. lividans TK21(pAMI11) and its isogenic strain S. lividans TK21(pIJ486). Transcriptional profiling of the bacterium that overproduces alpha-amylase mainly resulted in the upregulation of genes involved in the biogenesis and function of ribosomes, together with the upregulation of the genes involved in the redox processes, the ABC transporters, the central carbon, aminoacid and purine /pyrimidine metabolism. Moreover, some genes involved in oxidative stress were upregulated. The number of genes downregulated was much lower than the upregulated ones. Therefore, bacteria respond by favouring alpha-amylase overproduction that apparently does not cause damage to the cell.
Project description:The gene dagA encoding agarase in Streptomyces coelicolor was cloned in the multicopy plasmid pIJ486 generating plasmid pAGAs5. Plasmid pAGAs5 and pIJ486 were propagated in S. lividans TK21 to obtain S. lividans TK21(pAGAs5) and its isogenic strain S. lividans TK21(pIJ486). Transcriptional profiling of the bacterium that overproduces agarase mainly resulted in the downregulation of the genes involved in the biogenesis and function of ribosomes, together with the downregulation of the genes involved in nitrogen, aminoacids, purine/pyrimidine and central carbon metabolism as well as ABC transporters, redox processes and fatty acids biosynthesis. The number of genes upregulated in the agarase overproducer strain is lower than in the downregulated ones. Almost 50% of the dowregulated genes have been described as forming part of the stringent response in streptomycetes. Therefore, the overproduction of agarase may lead to a condition of nutrient depletion that triggers the stringent response.
Project description:Comparative genomic hybridization analysis of Streptomyces coelicolor A3(2) versus Streptomyces lividans 66 and Streptomyces lividans TK24 using high density 105,000 x 60-mer ink-jet in situ synthesized arrays.
Project description:The Streptomyces lividans lsp gene encodes a type II signal peptidase (Lsp) that cleaves the type II leader peptides of lipoproteins. Transcriptional profiling of the bacterium depleted of the lsp gene mainly resulted in deactivation of the sigma U regulon, as well as in downregulation of genes involved in the biogenesis and function of ribosomes and genes encoding some major secretory proteins as determined by hybridisation of commercially available S. lividans genome-wide microarrays. Almost 50% of the dowregulated genes have been described as forming part of the stringent response in streptomycetes. The gene encoding the S. lividans extracellular foldase, the lipoprotein FkpA, is equally downregulated. Therefore, the deletion of lsp from the S. livdans genome temporarily triggers a cellular stress where the stringent response is, at least, partially induced. All microarray analyses were performed with RNA samples obtained from three independent cultures grown under identical conditions. The cDNA obtained from each RNA preparation of the Lsp-deficient strain was hybridised with the cDNA obtained from the equivalent RNA preparation of the wild type strain (S. lividans TK21).
Project description:In order to define the impact of phosphate (Pi) availability on cellular metabolism the project aimed to perform a comparative analysis of the proteomes of two Streptomyces strains with different abilities to produce antibiotics, S. coelicolor and S. lividans as well as of the pptA mutant of S. lividans, grown low (1mM) and high (5mM) phosphate (Pi) availability conditions. Interestingly, in contrast to most Streptomyces species, S. coelicolor produces more antibiotics in Pi proficiency than in Pi limitation, S. lividans does not produce antibiotics in any Pi conditions and the pptA mutant produces antibiotics only in Pi limitation. This in-depth proteomic comparison of three Streptomyces strains (S. coelicolor, S. lividans wt and pptA mutant), in different growth conditions (time and Pi concentration in the medium) was performed on four biological replicates. Protein abundance changes were determined using two label-free mass spectrometry based-quantification methods: spectral count (SC) and MS1 ion intensities named XIC (for eXtracted Ion Current). Our proteomic data reveal for the first time, the impact of Pi availability on the abundance of approximately 4000 proteins of these Streptomyces strains with different abilities to produce antibiotics. The most striking feature differentiating these strains was the much higher abundance of enzymes of the respiratory chain in both phosphate conditions in S. coelicolor compared to the S. lividans strains.