Actividad antimicrobiana de Streptomyces sp. 6E3 aislado de concentrado de mineral* / Streptomyces sp. 6E3 antimicrobial activity isolated from mineral concentrate

RESUMEN El objetivo de este estudio fue determinar la actividad antimicrobiana de un cultivo de Streptomyces sp. 6E3 aislado de minerales frente a diferentes cepas patógenas, producir un extracto y estimar la concen tración mínima inhibitoria (CMI) de las fracciones contra Staphylococcus aureus resistente a meticilina (SARM). La cepa Streptomyces sp. 6E3 mostró actividad antimicrobiana principalmente contra Staphy lococcus aureus (S. aureus). Cinco de las seis fracciones presentaron actividad antimicrobiana y la más efectiva dio una CMI de 0,88 ug/mL frente a S. aureus ATCC 33862, 0,44 ug/mL frente a S. aureus ATCC 43300 y 1,76 ug/mL frente a S. aureus cepa SARM. Streptomyces sp. 6E3 tiene un potencial antimicrobiano frente a cepas de S. aureus resistentes a meticilina y no resistentes, siendo de interés la realización de más estudios sobre sus metabolitos activos.

ABSTRACT The objectives of this study were to determine the antimicrobial activity of a culture of Streptomyces sp. 6E3 isolated from minerals against different pathogenic strains, to produce an extract and to estimate the minimum inhibitory concentration (MIC) of the fractions against methicillin-resistant Staphylococ cus aureus (MRSA). Streptomyces sp. 6E3 showed antimicrobial activity primarily against Staphylococcus aureus (S. aureus). Five of the six fractions presented antimicrobial activity and the most effective gave a MIC of 0.88 ug / mL against S. aureus ATCC 33862, 0.44 ug / mL against S. aureus ATCC 43300 and 1.76 ug / mL vs. a S. aureus MRSA strain. Streptomyces sp. 6E3 has an antimicrobial potential against S. aureus strains resistant to methicillin and non-resistant, being of interest carrying out of more studies on its active metabolites.

Streptomyces lunalinharesii 235 prevents the formation of a sulfate-reducing bacterial biofilm

ABSTRACT Streptomyces lunalinharesii strain 235 produces an antimicrobial substance that is active against sulfate reducing bacteria, the major bacterial group responsible for biofilm formation and biocorrosion in petroleum reservoirs. The use of this antimicrobial substance for sulfate reducing bacteria control is therefore a promising alternative to chemical biocides. In this study the antimicrobial substance did not interfere with the biofilm stability, but the sulfate reducing bacteria biofilm formation was six-fold smaller in carbon steel coupons treated with the antimicrobial substance when compared to the untreated control. A reduction in the most probable number counts of planktonic cells of sulfate reducing bacteria was observed after treatments with the sub-minimal inhibitory concentration, minimal inhibitory concentration, and supra-minimal inhibitory concentration of the antimicrobial substance. Additionally, when the treated coupons were analyzed by scanning electron microscopy, the biofilm formation was found to be substantially reduced when the supra-minimal inhibitory concentration of the antimicrobial substance was used. The coupons used for the biofilm formation had a small weight loss after antimicrobial substance treatment, but corrosion damage was not observed by scanning electron microscopy. The absence of the dsrA gene fragment in the scraped cell suspension after treatment with the supra-minimal inhibitory concentration of the antimicrobial substance suggests that Desulfovibrio alaskensis was not able to adhere to the coupons. This is the first report on an antimicrobial substance produced by Streptomyces active against sulfate reducing bacteria biofilm formation. The application of antimicrobial substance as a potential biocide for sulfate reducing bacteria growth control could be of great interest to the petroleum industry.

Kinetic properties of Streptomyces canarius L- Glutaminase and its anticancer efficiency

Abstract L-glutaminase was produced by Streptomyces canarius FR (KC460654) with an apparent molecular mass of 44 kDa. It has 17.9 purification fold with a final specific activity 132.2 U/mg proteins and 28% yield recovery. The purified L-glutaminase showed a maximal activity against L-glutamine when incubated at pH 8.0 at 40 °C for 30 min. It maintained its stability at wide range of pH from 5.0 11.0 and thermal stable up to 60 °C with Tm value 57.5 °C. It has high affinity and catalytic activity for L-glutamine (Km 0.129 mM, Vmax 2.02 U/mg/min), followed by L-asparagine and L-aspartic acid. In vivo, L-glutaminase showed no observed changes in liver; kidney functions; hematological parameters and slight effect on RBCs and level of platelets after 10 days of rabbit's injection. The anticancer activity of L-glutaminase was also tested against five types of human cancer cell lines using MTT assay in vitro. L-glutaminase has a significant efficiency against Hep-G2 cell (IC50, 6.8 μg/mL) and HeLa cells (IC50, 8.3 μg/mL), while the growth of MCF-7 cells was not affected. L-glutaminase has a moderate cytotoxic effect against HCT-116 cell (IC50, 64.7 μg/mL) and RAW 264.7 cell (IC50, 59.3 μg/mL).

Clavulanic acid production by the MMS 150 mutant obtained from wild type Streptomyces clavuligerus ATCC 27064

Clavulanic acid (CA) is a powerful inhibitor of the beta-lactamases, enzymes produced by bacteria resistants to penicillin and cefalosporin. This molecule is produced industrially by strains of Streptomyces clavuligerus in complex media which carbon and nitrogen resources are supplied by inexpensive compounds still providing high productivity. The genetic production improvement using physical and chemical mutagenic agents is an important strategy in programs of industrial production development of bioactive metabolites. However, parental strains are susceptible to loss of their original productivity due genetic instability phenomenona. In this work, some S. clavuligerus mutant strains obtained by treatment with UV light and with MMS are compared with the wild type (Streptomyces clavuligerus ATCC 27064). The results indicated that the random mutations originated some strains with different phenotypes, most divergent demonstrated by the mutants strains named AC116, MMS 150 and MMS 54, that exhibited lack of pigmentation in their mature spores. Also, the strain MMS 150 presented a larger production of CA when cultivated in semi-synthetics media. Using other media, the wild type strain obtained a larger CA production. Besides, using the modifed complex media the MMS 150 strain showed changes in its lipolitic activity and a larger production of CA. The studies also allowed finding the best conditions for a lipase activity exhibited by wild type S. clavuligerus and the MMS150 mutant.

Characterization of carbamoyl phosphate synthetase of Streptomyces spp.

Carbamoyl phosphate synthetase (CPS) activity in Streptomyces lividans was repressed (70%) by addition of arginine and uracil in the growth medium. Enzyme activity was also inhibited by UMP and activated by ornithine and IMP. Pattern of inhibition and activation was similar irrespective of whether the cells were grown in medium supplemented with arginine or with uracil. A mutant of S. coelicolor with dual auxotrophy for arginine and uracil possessed only about 20% of CPS activity compared to the wild-type strain. An activity staining protocol has been developed for CPS enzyme. Using this method a single CPS band has been observed in the crude extracts of Escherichia coli as well as in S. lividans. Taken together, our results supported the conclusion that Streptomyces species might possess a single CPS enzyme unlike other gram-positive bacteria, which show the presence of two pathway-specific isozymes (Bacillus) or none (Lactobacillus and Leuconostoc).

Extracellular serine-proteinases isolated from Streptomyces alboniger: Partial characterization and effect of aprotinin on cellular structure

Streptomyces alboniger ATCC 12461 grown in brain heart infusion (BHI) medium produced two extracellular serine-proteinases, denoted SP I and SP II, which were purified by ammonium sulfate precipitation and aprotinin-agarose affinity chromatography. SP I was purified 88,9-fold and SP II 66,7- fold, with 33.4 percent and 10.4 percent yield, respectively. The optimum pH for the proteinases activity, using a-N-p-tosyl-L-arginine-methyl ester (TAME) as substrate, was 9-10 and the optimum temperature was 37ºC. The proteolytic activity of SP I and SP II was inhibited by aprotinin and SP I was partially inhibited by leupeptin, both serine-proteinase inhibitors. S. alboniger growth in BHI-liquid medium decreased when 5 mg/ml, 10 mg/ml of aprotinin was used, being completely inhibited with 20 mg/ml and 40 mg/ml. At the ultrastructural level, aprotinin-treated S. alboniger cells showed swelling of the bacterial body and condensation of the genetic material, probably related to the inhibition of its growth

Ionic valency of vanadium or chromium and the enzymatic activity in Streptomyces caeruleus

The results of this investigation establish the fact that addition of 10-6 - 10-4 M chromium to the culture media, mostly stimulated the test intra-and extra-cellular enzymes of Streptomyces caeruleus. In most cases the hexavalent ion was more effective than the trivalent. Furthermore, Cr6+, was more inhibitory to dry weight gain than Cr3+. In the meantime, V2+ was mostly suppressive [except on Ac-P and GPT], whereas, V5+ was mostly stimulatory [endopeptidase being the exception]. The dry weight gain was slightly reduced by the former vanadium form and severely suppressed by the latter form. Accordingly, it seemed that the toxicity of these transitional elements was more apparent when supplemented in their high valency state accompanied by increased enzyme activity. The latter could be attenuated by lowering the valency of the cationic form of the ions

Efeitos da acriflavina em diferentes espécies de streptomyces produtores de actinomicina / Effects of acriflavine on three actionomycin producer species of Streptomyces

O tratamento de três diferentes espécies de Streptomyces com acriflavina, resultou na perda da produçäo de actinomicina em 5-12% das colônias isoladas nestas linhagens. S. felleus e S. regensis mostraram mais instabilidade do que S. parvulus. A produçäo de pigmento amarelo característica destas linhagens produtoras de actinomicina foi totalmente eliminada. A instabilidade genética destas linhagens pode ser atribuída a elementos extracromossômicos

Producción de enzimas por streptomycoses sp cresciendo con caparazón de camarón como sustrato / Enzyme production of streptomyces up growing on shrimp shell as substrate

Se hizo un estudio comparativo en cuanto a la producción de enzimas por ima ceá de Streptomyces sp, utilizando como substrato caparazón de camarón desmineralizado ó quitina semipurificada. Se encontró que la producción de quitinasas está asociada al crecimiento microbiano cuando se usa como substrato caparazón de camarón, alcanzando una producción máxima de quitinasa, qutitosanasa, carboximetilcelulasa y de proteasa a las 96 h de incubación. Cuando el substrato fue la quitina, se obtuvo un máximo en la producción quitinolítica y quitosanolítica al alcanzar la fase de crecimiento estacionario. El crecimiento de Streptomyces sp fue mayor en caparazón de camarón que en quitina, siendo muy pequeñas las velocidades específicas de crecimiento tanto en caparazón de camarón como en quitina semipurificada