Phagensensibilität, Zellwand-Zusammensetzung und Taxonomie von Actinomyceten

Prauser, H.; Falta, Rosmarie

doi:10.1002/jobm.3630080106

Cited by 69 publications

(7 citation statements)

References 15 publications

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“…To determine TopA protein levels, crude cell extracts were prepared from 18-h cultures in 79 medium (Prauser and Falta, 1968). Cell lysate proteins (5 μg in total) were separated in a 10% denaturing polyacrylamide gel before being transferred to a nitrocellulose membrane.…”

Section: Methodsmentioning

confidence: 99%

Transcriptional Response of Streptomyces coelicolor to Rapid Chromosome Relaxation or Long-Term Supercoiling Imbalance

et al. 2019

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Negative DNA supercoiling allows chromosome condensation and facilitates DNA unwinding, which is required for the occurrence of DNA transaction processes, i.e., DNA replication, transcription and recombination. In bacteria, changes in chromosome supercoiling impact global gene expression; however, the limited studies on the global transcriptional response have focused mostly on pathogenic species and have reported various fractions of affected genes. Furthermore, the transcriptional response to long-term supercoiling imbalance is still poorly understood. Here, we address the transcriptional response to both novobiocin-induced rapid chromosome relaxation or long-term topological imbalance, both increased and decreased supercoiling, in environmental antibiotic-producing bacteria belonging to the Streptomyces genus. During the Streptomyces complex developmental cycle, multiple copies of GC-rich linear chromosomes present in hyphal cells undergo profound topological changes, from being loosely condensed in vegetative hyphae, to being highly compacted in spores. Moreover, changes in chromosomal supercoiling have been suggested to be associated with the control of antibiotic production and environmental stress response. Remarkably, in S. coelicolor , a model Streptomyces species, topoisomerase I (TopA) is solely responsible for the removal of negative DNA supercoils. Using a S. coelicolor strain in which topA transcription is under the control of an inducible promoter, we identified genes involved in the transcriptional response to long-term supercoiling imbalance. The affected genes are preferentially organized in several clusters, and a supercoiling-hypersensitive cluster (SHC) was found to be located in the core of the S. coelicolor chromosome. The transcripts affected by long-term topological imbalance encompassed genes encoding nucleoid-associated proteins, DNA repair proteins and transcriptional regulators, including multiple developmental regulators. Moreover, using a gyrase inhibitor, we identified those genes that were directly affected by novobiocin, and found this was correlated with increased AT content in their promoter regions. In contrast to the genes affected by long-term supercoiling changes, among the novobiocin-sensitive genes, a significant fraction encoded for proteins associated with membrane transport or secondary metabolite synthesis. Collectively, our results show that long-term supercoiling imbalance globally regulates gene transcription and has the potential to impact development, secondary metabolism and DNA repair, amongst others.

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Section: Methodsmentioning

confidence: 99%

Transcriptional Response of Streptomyces coelicolor to Rapid Chromosome Relaxation or Long-Term Supercoiling Imbalance

et al. 2019

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“…The pWHM3Hyg plasmid (5.9 kbp) ( 32 ) was isolated using alkaline lysis and column purification based on a modified version of the manufacturer's (Syngen) procedure. After 48 h of growth in liquid 79 medium ( 43 ) supplemented with hygromycin, S. coelicolor hyphae were collected by centrifugation and suspended in the manufacturer's buffer containing 25 mg/ml of lysozyme. Hyphae were incubated at 30°C (or 42°C if isolated from heat-shocked cells) for 5 min.…”

Section: Methodsmentioning

confidence: 99%

The Coordinated Positive Regulation of Topoisomerase Genes Maintains Topological Homeostasis in Streptomyces coelicolor

et al. 2016

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Maintaining an optimal level of chromosomal supercoiling is critical for the progression of DNA replication and transcription. Moreover, changes in global supercoiling affect the expression of a large number of genes and play a fundamental role in adapting to stress. Topoisomerase I (TopA) and gyrase are key players in the regulation of bacterial chromosomal topology through their respective abilities to relax and compact DNA. Soil bacteria such as Streptomyces species, which grow as branched, multigenomic hyphae, are subject to environmental stresses that are associated with changes in chromosomal topology. The topological fluctuations modulate the transcriptional activity of a large number of genes and in Streptomyces are related to the production of antibiotics. To better understand the regulation of topological homeostasis in Streptomyces coelicolor, we investigated the interplay between the activities of the topoisomerase-encoding genes topA and gyrBA. We show that the expression of both genes is supercoiling sensitive. Remarkably, increased chromosomal supercoiling induces the topA promoter but only slightly influences gyrBA transcription, while DNA relaxation affects the topA promoter only marginally but strongly activates the gyrBA operon. Moreover, we showed that exposure to elevated temperatures induces rapid relaxation, which results in changes in the levels of both topoisomerases. We therefore propose a unique mechanism of S. coelicolor chromosomal topology maintenance based on the supercoiling-dependent stimulation, rather than repression, of the transcription of both topoisomerase genes. These findings provide important insight into the maintenance of topological homeostasis in an industrially important antibiotic producer.IMPORTANCE We describe the unique regulation of genes encoding two topoisomerases, topoisomerase I (TopA) and gyrase, in a model Streptomyces species. Our studies demonstrate the coordination of topoisomerase gene regulation, which is crucial for maintenance of topological homeostasis. Streptomyces species are producers of a plethora of biologically active secondary metabolites, including antibiotics, antitumor agents, and immunosuppressants. The significant regulatory factor controlling the secondary metabolism is the global chromosomal topology. Thus, the investigation of chromosomal topology homeostasis in Streptomyces strains is crucial for their use in industrial applications as producers of secondary metabolites.

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“…The cells used for ubiquinone analysis and DNA extraction were obtained by cultivation at 28 "C for 48 h (24 h for ubiquinones) in 100 ml flasks containing 20 ml medium 79 (Prauser & Falta, 1968) shaken at 220r.p.m. DNA was isolated and its G + C content determined by HPLC as described by Martin et al (1997).…”

Section: Methodsmentioning

confidence: 99%

A taxonomic study of bacteria isolated from grasses: a proposed new species Pseudomonas graminis sp. nov.

Behrendt

Ulrich

Schümann

et al. 1999

International Journal of Systematic and Evolutionary Microbiology

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A taxonomic study of bacteria isolated from grasses : a proposed new species Pseudomonas graminis sp. nov.Undine Behrendt,' Andreas Ulrich,2 Peter S~humann,~ Wilfried E r l e~,~ Jutta Burghardt5 and Wolfgang Seyfarth2 The taxonomic position of a yellow-pigmented group of bacteria, isolated from the phyllosphere of grasses was investigated. Results obtained from restriction analysis of amplified 16s rDNA with seven endonucleases (Cfol, Haelll, Alul, Hinfl, Mspl, Sau3A and ScrFI) showed identical restriction patterns for each enzyme of all isolates studied, which suggests that all strains belong to the same species. The grass isolates displayed the characteristics of the genus Pseudomonas. They were Gram-negative, aerobic and rod-shaped with polar flagella. Isolates were catalase-positive and oxidase-negative, and unable to oxidize or ferment glucose with the production of acid. The isolates did not reduce nitrate to nitrite but were able to utilize a wide range of compounds individually as a sole carbon source, with preference being given to the utilization of monosaccharides. The disaccharides tested were not utilized as substrates. The DNA base compositions of the tested strains ranged from 60 to 61 mol% G+C. The major isoprenoid quinone of each was ubiquinone Q-9 and hydroxy fatty acids were represented b y 3-hydroxydodecanoic acid and 2-hydroxydodecanoic acid. Comparison of 165 rDNA sequences showed that the bacteria were members of the genus Pseudomonas, with similarity values between 91.5 and 97.7 O/ O. DNA-DNA hybridization studies with closely related neighbours revealed a low level of homology (< 27 YO), indicating that the isolates represent an individual species.On the basis of phenotypic and phylogenetic analyses a new species, Pseudomonas graminis sp. nov. (type strain DSM 11 3633, is proposed.

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Phagensensibilität, Zellwand-Zusammensetzung und Taxonomie von Actinomyceten

Cited by 69 publications

References 15 publications

Transcriptional Response of Streptomyces coelicolor to Rapid Chromosome Relaxation or Long-Term Supercoiling Imbalance

Transcriptional Response of Streptomyces coelicolor to Rapid Chromosome Relaxation or Long-Term Supercoiling Imbalance

The Coordinated Positive Regulation of Topoisomerase Genes Maintains Topological Homeostasis in Streptomyces coelicolor

A taxonomic study of bacteria isolated from grasses: a proposed new species Pseudomonas graminis sp. nov.

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