Crystallization and preliminary X-ray diffraction studies of a complex of extracellular lipase from Streptomyces rimosus with the inhibitor 3,4-dichloroisocoumarin.

A recombinant lipase (triacylglycerol acylhydrolase; EC 3.1.1.

Structural characterization of extracellular lipase from Streptomyces rimosus: assignment of disulfide bridge pattern by mass spectrometry.

The cloning, sequencing and high-level expression of the gene encoding extracellular lipase from Streptomyces rimosus R6-554W have been recently described, and the primary structure of this gene product was deduced using a bioinformatic approach. In this study, capillary electrophoresis-on-the-chip and mass spectrometry were used to characterize native and overexpressed extracellular lipase protein from S. rimosus .

A Simple and Rapid Method of Transformation of Streptomyces rimosus R6 and Other Streptomycetes by Electroporation.

Usually plasmid DNA is introduced into Streptomyces strains by polyethylene glycol-mediated transformation of protoplasts. However, many Streptomyces strains are only poorly or not at all transformable via protoplasts. Therefore, we have optimized the parameters critical for the application of electrotransformation of plasmid DNA into Streptomyces species.

The 387 kb linear plasmid pPZG101 of Streptomyces rimosus and its interactions with the chromosome.

The linear plasmid pPZG101 of Streptomyces rimosus R6 was restriction mapped with the enzymes AseI, BfrI, DraI and XbaI. It is 387 kb in size and the ends are inverted repeats of at least 95 kb in length. Twenty spontaneous morphological variants and seventeen auxotrophic mutants were screened for changes in the plasmid.

The temperate phages RP2 and RP3 of Streptomyces rimosus.

The oxytetracycline-producing Streptomyces rimosus strains R6-65 and R7 (ATCC 10970) are lysogenic for the two narrow-host-range phages RP2 and RP3. Both phages are released at low frequency from the lysogenic strains and form plaques on 'cured' S. rimosus strains.

Construction of two stable bifunctional plasmids for Streptomyces spp. and Escherichia coli.

Two bifunctional plasmid vectors pZG5 (7.45 kb) and pZG6 (6.95 kb), for gene transfer between Streptomyces spp.

Structural instability of a bifunctional plasmid pZG1 and single-stranded DNA formation in Streptomyces.

Structural instability of a hybrid plasmid pZG1, consisting of Escherichia coli pBR322 and Streptomyces pIJ350 plasmids, has been studied in Streptomyces. After transformation of S. lividans 1326 and S.

Biochemical and genetic studies of a histidine regulatory mutant of Streptomyces coelicolor A3 (2).

The specific activities of three enzymes in a histidine regulatory mutant RF59 of Streptomyces coelicolor A3(2) resistant to the histidine analogue 1,2,4-triazolealanine (TRA) were measured and compared to the activity of the wild type strain. The first enzyme of the histidine pathway, phosphorybosyl-ATP-pyrophosphorylase (PR-ATP-pyrophosphorylase), of mutant RF59 and the wild type was sensitive to allosteric inhibition by L-histidine and hence feed-back inhibition was not affected by mutation, although the specific activity in the mutant was 2.9 fold higher than in the wild type.

Genetic interactions in Streptomyces rimosus mediated by conjugation and by protoplast fusion.

The development of a protoplast fusion technique for oxytetracycline-producing Streptomyces rimosus strains, and its evaluation for the application for a breeding programme, has been described. Treatment of S. rimosus protoplasts with 40% (w/v) PEG 1550 for 30 min gave optimal numbers of recombinants ranging from 1 to 10% of the total progeny.

Optimal Cultural and Physiological Conditions for Handling Streptomyces rimosus Protoplasts.

A general procedure for manipulating protoplasts of three Streptomyces rimosus strains was developed. More than 50% regeneration efficiency was obtained by optimizing the osmotic stabilizer concentrations and modifying the plating procedure. Preparation and regeneration of protoplasts were studied by both phase-contrast and electron microscopy.

Isolation of Streptomyces rimosus Mutants with Reduced Actinophage Susceptibility.

The infection of Streptomyces rimosus by the virulent actinophage RP1 was partially characterized. RP1 infection of the host cells results in a dramatic decrease in viable cell count, followed by reduced antibiotic production. Phage-resistant mutants were isolated after mutagenic treatment and RP1 selective pressure.

Characterization and persistence of actinophage RP2 isolated from Streptomyces rimosus ATCC 10970.

While searching for true lysogens among oxytetracycline-producing Streptomyces rimosus strains, free phage particles were detected and isolated from a liquid culture of S. rimosus ATCC 10970 (R7). The actinophage, designated RP2, appears to be a typical temperate DNA phage producing turbid plaques on the sensitive strain S.