Leandro M. Garrido

Insights in the glycosylation steps during biosynthesis of the antitumor anthracycline cosmomycin: characterization of two glycosyltransferase genes

Glycosylation pattern in cosmomycins is a distinctive feature among anthracyclines. These antitumor compounds possess two trisaccharide chains attached at C-7 and C-10, each of them with structural variability, mainly at the distal deoxysugar moieties. We have characterized a 14-kb chromosomal region from Streptomyces olindensis containing 13 genes involved in cosmomycin biosynthesis. Two of the genes, cosG and cosK, coding for glycosyltransferase were inactivated with the generation of five new derivatives. Structural elucidation of these compounds showed altered glycosylation patterns indicating the capability of both glycosyltransferases of transferring deoxysugars to both sides of the aglycone and the flexibility of CosK with respect to the deoxysugar donor. A model is proposed for the glycosylation steps during cosmomycins biosynthesis.

A rapid and sensitive method for the screening of DNA intercalating antibiotics

An improved, rapid and inexpensive gel mobility shift assay was developed for the screening of anthracycline antibiotics. The assay based on the intercalation activity of these molecules into dsDNA was used to assess the activity of partially purified antibiotics. Detection limits were of 0.1 ng ml−1 with an average run time of 2 h. The assay is potentially useful for high throughput screening in bioprospecting, for monitoring fermentation production phases and downstream purification process.

Effect of pH on the production of the antitumor antibiotic retamycin by Streptomyces olindensis

The effect of pH on cell growth and retamycin production in batch bioreactor cultures of Streptomyces olindensis ICB20 was investigated. In fermentations pH‐controlled over the range 6.0–8.0, the highest retamycin production was achieved at pH 7.0, and the maximum concentration of retamycin, about 1.36 A (absorbance) units, was about 43, 58 and 232% higher than the values obtained at pH 7.5, 6.0 and 8.0 respectively.

Genome Sequence of Streptomyces olindensis DAUFPE 5622, Producer of the Antitumoral Anthracycline Cosmomycin D

ABSTRACT Streptomyces olindensis DAUFPE 5622, which was isolated from a Brazilian soil sample, produces the antitumor anthracycline cosmomycin D. The genome sequence is 9.4 Mb in length, with a G+C content of 71%. Thirty-four putative secondary metabolite biosynthetic gene clusters were identified, including the cosmomycin D cluster.

Draft Genome Sequence of Curtobacterium sp. Strain ER1/6, an Endophytic Strain Isolated from Citrus sinensis with Potential To Be Used as a Biocontrol Agent

ABSTRACT Herein, we report a draft genome sequence of the endophytic Curtobacterium sp. strain ER1/6, isolated from a surface-sterilized Citrus sinensis branch, and it presented the capability to control phytopathogens. Functional annotation of the ~3.4-Mb genome revealed 3,100 protein-coding genes, with many products related to known ecological and biotechnological aspects of this bacterium.

Metabolic flux analysis for directing metabolism of Streptomyces olindensis from growth to anti-tumor drug (cosmomycin) production

Background Cosmomycin, an aromatic polyketide antibiotic complex produced by Streptomyces olindensis, belongs to anthracycline family of chemotherapy drugs. It is a powerful antitumor drug similar to doxorubicin and daunorubicin. The structure of cosmomycin consists of one tetracycline aglycon (β-rhodomycinone) and six deoxysugars (two dTDPL-2-deoxifucose, two dTDP-L-rodosamine and two dTDPL-rodinose). The tetracycline aglycon, a polyketide structure, is obtained by condensation of one propionyl-CoA with nine acetate molecules derived from malonyl-CoA by the action of enzymes known as minimal Polyketide Synthetases (minimal PKS). Model construction The in silico metabolism was reconstructed involving more than 240 stoichiometrically balanced metabolic reactions in matrix formalism using the information from the literature and databases (top-down and bottom-up). Then, computational metabolic flux balancing method was used in order to obtain fluxes of all the metabolic reactions with linear programming and optimisation in GAMS environment (General Algebraic Modeling System). The objective function of optimisation was either the maximisation of the specific growth rate or the maximisation of the specific cosmomycin production rate. The experimental specific glucose uptake and growth rates were used as the model constraints, as appropriate. The solution of the metabolic model gave the specific growth and/or product formation rates as well as the specific rates of all 242 metabolic reactions.