Search results for "Streptomyce"

The DNA cytosine methylome of Streptomyces coelicolor

2019

Epigenetic control of Streptomyces coelicolor differentiation

2015

DNA cytosine methylation is one of the most important epigenetic modifications in eukaryotes regulating chromatin organization, genome maintenance and gene expression. The role of DNA cytosine methylation in prokaryotes has not been deeply investigated. In Escherichia coli cytosine methylation regulates gene expression during the stationary phase and cytosine hypermethylation leads to chromosomal DNA cleavage and cell death. Streptomyces coelicolor is a mycelial soil microorganism, which exhibits a complex life cycle that includes three different cell types: unigenomic spores, a compartmentalized mycelium (MI) and a multinucleated mycelium (substrate and aerial mycelium, MII). The importanc…

Streptomyces coelicolor: DNA methylation and differentiation

2014

DNA cytosine methylation is an epigenetic modification regulating many biological processes in eukaryotes, including chromatin organization, genome maintenance and gene expression. The role of DNA cytosine methylation in prokaryotes has not been deeply investigated. In Escherichia coli it was recently demonstrated that cytosine methylation regulates gene expression during stationary phase [1] and that an induced state of cytosine hypermethylation leads to chromosomal DNA cleavage and cell death [2]. Streptomyces coelicolor is a mycelial soil microorganism, which exhibits a complex life cycle that includes three different cell types: unigenomic spores, a compartmentalized mycelium (MI) and a…

Streptomyces coelicolor: DNA methylation and differentiation - Palermo 27-06-2014

2014

DNA methylation is an epigenetic modification regulating many aspects of biological processes. DNA cytosine methylation plays mainly a regulatory role in chromatin organization, genome maintenance and gene expression in eukaryotes, while its role has not been deeply investigated in prokaryotes. Differently, DNA adenine methylation regulates chromosome replication, DNA repair, transposition of insertion elements in prokaryotes, while it is supposed to have exclusively a role in regulating gene expression and DNA replication in mitochondria. Streptomyces coelicolor is a soil-dwelling Gram-positive bacterium that exhibits a complex life cycle, with three different cell types (unigenomic spores…

Expression in Streptomyces lividans of Nonomuraea genes cloned in an artificial chromosome

2004

A bacterial artificial chromosomal library of Nonomuraea sp. ATCC39727 was constructed using Escherichia coli-Streptomyces artificial chromosome (ESAC) and screened for the presence of dbv genes known to be involved in the biosynthesis of the glycopeptide A40926. dbv genes were cloned as two large, partially overlapping, fragments and transferred into the host Streptomyces lividans, thus generating strains S. lividansColon, two colonsNmESAC50 and S. lividansColon, two colonsNmESAC57. The heterologous expression of Nonomuraea genes in S. lividans was successfully demonstrated by using combined RT-PCR and proteomic approaches. MALDI-TOF analysis revealed that a Nonomuraea ABC transporter is e…

Developmental control of the heat-shock stress regulon in Streptomyces coelicolor

1995

In the differentiating eubacterium Streptomyces coelicolor, nutritional imbalances activate a developmental programme which involves the heat-shock stress regulon. In liquid batch cultures, the growth curve could be separated into four components: rapid growth 1 (RG1), transition (T), rapid growth 2 (RG2) and stationary (S). Patterns of gene expression in cultures subjected to heat shock in various phases were recorded on two-dimensional gels and analysed using advanced statistical methods. The responses of all heat-shock proteins (HSPs) were highly dependent upon the growth phase, thus demonstrating that the four phases of growth were physiologically distinct. For many HSPs, the levels of …

Cloning and sequencing of the dnaK region of Streptomyces coelicolor A3(2)

1993

Abstract The dnaK homologue of Streptomyces coelicolor A3(2) strain M145 has been cloned and sequenced. Nucleotide sequence analysis of a 2.5-kb region revealed an open reading frame (ORF) encoding a predicted DnaK protein of 618 amino acids (Mr = 66 274). The dnaK coding sequence displays extreme codon bias and shows a strong preference for CGY and GGY, for Arg and Gly codons, respectively. The predicted DnaK sequence has a high Lys:Arg ratio which is not typical of streptomycete proteins. The region immediately downstream from dnaK contains an ORF for a GrpE-like protein; the predicted start codon of grpE overlaps the last two codons of dnaK, indicating that the two genes are translationa…

Shifts in diversity and microscale distribution of the adapted bacterial phenotypes due to Hg(II) spiking in soil.

2003

In a previous experiment [Ranjard et al. (2000) FEMS Microbiol Ecol 31:107–115], the spatial heterogeneity of a mercury impact on soil bacterial community was revealed by an increase of mercury-resistant (HgR) bacterial numbers in the outer fraction and the sand fractions when compared to those in the silt fractions. The objectives of the present study were (i) to investigate whether mercury exposure affects the diversity and the distribution within the various fractions of the HgR populations and (ii) to evaluate the contribution of the HgR populations to the overall community adaptation. A total of 236 strains isolated before (104 isolates) and 30 days (132 isolates) after spiking were ch…

STRATEGIE PER IL MIGLIORAMENTO DELLA PRODUZIONE E LO SVILUPPO DI MOLECOLE AD ATTIVITÀ ANTIBIOTICA DI ORIGINE NATURALE O DI SINTESI CHIMICA

The emergence of multi-drug resistant (MDR) bacterial strains is an urgent problem derived from the widespread and uncontrolled use of antibiotics. Therefore, new arrays of lead compounds exerting antimicrobial activity are necessary to contrast the spreading of MDR pathogens. Between 1980 and 2003, the interest in scientific research programs aimed to the new drug discovery by large pharmaceutical companies progressively decreased due to increasing costs in the respect of i) the low discovery rate of new leads, ii) the small amounts of product recovery needing process optimization and, finally, iii) regulatory obstacles associated with long-lasting pre-clinical and clinical trials for ther…

Phosphate-controlled regulator for the biosynthesis of the dalbavancin precursor A40926

2007

ABSTRACT The actinomycete Nonomuraea sp. strain ATCC 39727 produces the glycopeptide A40926, the precursor of the novel antibiotic dalbavancin. Previous studies have shown that phosphate limitation results in enhanced A40926 production. The A40926 biosynthetic gene ( dbv ) cluster, which consists of 37 genes, encodes two putative regulators, Dbv3 and Dbv4, as well as the response regulator (Dbv6) and the sensor-kinase (Dbv22) of a putative two-component system. Reverse transcription-PCR (RT-PCR) and real-time RT-PCR analysis revealed that the dbv14 - dbv8 and the dbv30 - dbv35 operons, as well as dbv4 , were negatively influenced by phosphate. Dbv4 shows a putative helix-turn-helix DNA-bind…