Antibacterial activity of phytopathogenic Streptomyces strains against bacteria associated to clinical diseases / Atividade antimicrobiana de Streptomyces fitopatogênicas contra bactérias associadas a doenças de importância clínica

The genus Streptomyces is associated with the ability to produce and excrete a variety of bioactive compounds, such as antibiotic, antifungal and antiviral. Biological active polyketide and peptide compounds with applications in medicine, agriculture and biochemical research are synthesized by PKS-I and NRPS genes. The evaluation of the presence of these genes associated with the biosynthesis of secondary metabolites in different phytopathogenic Streptomyces strains were performed using degenerated primers. The positive signal was observed in 58/63 Streptomyces strains for NRPS gene, 43/63 for PKS-I, and for PKS-II all the 63 strains showed positive signal of amplification. These strains also were tested with double layer agar-well technique against bacterial with clinical importance, and it was possible to observe the Streptomyces spp. strains were able to inhibit the growth of 14, 20, 13 and 3 isolates Gram-positive and Gram-negative bacteria, Staphylococcus aureus (ATCC 25923), Bacillus cereus (ATCC 14579), Pseudomonas aeruginosa (ATCC 27853) and Escherichia coli (ATCC 11775) respectively. The Streptomyces sp. strains IBSBF 2019 and IBSBF 2397 showed antibacterial activity against all four bacteria-target tested.(AU)

O gênero Streptomyces apresenta alta capacidade de produzir e excretar uma grande variedade de compostos biologicamente ativos, como antibióticos, antifúngicos e antivirais. Compostos biologicamente ativos de policetídeos e peptídeos com aplicações na medicina, agricultura e pesquisas bioquímicas são sintetizados pelos genes PKS-I e NRPS. A avaliação da presença desses genes associados à biossíntese de metabólitos secundários em diferentes linhagens de Streptomyces fitopatogênicas foi realizada através do uso de primers degenerados. O sinal positivo foi observado em 58/63 linhagens de Streptomyces para o gene NRPS, 43/63 para o gene PKS-I e, para o gene PKS-II, todas as 63 linhagens apesentaram o sinal positivo de amplificação. Essas linhagens também foram testadas através da técnica de dupla camada contra bactérias de importância clínica e foi possível observar que as linhagens de Streptomyces spp. foram capazes de inibir o crescimento de 14, 20, 13 e 3 isolados de bactérias Gram-positivas e Gram-negativas, Staphylococcus aureus (ATCC 25923), Bacillus cereus (ATCC 14579), Pseudomonas aeruginosa (ATCC 27853) e Escherichia coli (ATCC 11775), respectivamente. As linhagens de Streptomyces sp. ISBSF 2019 e 2397 apresentaram atividade antibacteriana contra todas as bactérias-alvo testadas.(AU)

Evaluation of Antigen Preparation Methods for Polyclonal Antibody Production against Streptomyces spp.

Aim: To determine the optimum antigen preparation method for producing specific polyclonal antibody specific for Streptomyces species. Study Design: Experimental study. Place and Duration of Study: Faculty of Science, Mahasarakham University, Mahasarakham Province, Thailand, between May 2011 and December 2011. Methodology: Two Streptomyces isolates were used for antisera production. The sonication method was chosen for antigen preparation. Antigen suspensions were emulsified with incomplete Freund’s adjuvant and 1 ml was injected into rabbit thigh muscle for the first, second and third immunization. The fourth and fifth immunizations were injected intravenously. Antibody titer, detection limit and specificity were measured using indirect-ELISA. Streptomyces antigen mixed with soil was investigated. Results: The 5 min sonication method gave a higher protein than other test methods, so this protocol was chosen for all subsequent work. The sonicated Streptomyces antigen was used for polyclonal antibody production. At week 7, the rabbit anti-Streptomyces sp. isolate STPR78 antibody and anti-Streptomyces sp. isolate STPR84 antibody gave maximum titers at 1:64000 and 1:32000, respectively. The detection limit of the anti-Streptomyces antibodies was 125 ng and 250 ng, respectively. Both anti-Streptomyces antibodies were also found to have good specificity. Minimal cross-reactivity was detected with antigens from other test bacteria. Regrettably however, neither antibody was capable of detecting Streptomyces spp. STPR78 or STPR84 in inoculated soil. Conclusion: A specific and high titer of polyclonal antibody was produced using sonicated antigen.

Population densities and genetic diversity of actinomycetes associated to the rhizosphere of Theobroma cacao / Densidades populacionais e diversidade genética de actinomicetos associados a rizosfera de Theobroma cacao

In spite of the acknowledged importance of growth-promoting bacteria, only a reduced number of studies were conducted with these microorganisms on Theobroma cacao. The objectives of this work were to study the population densities and genetic diversity of actinomycetes associated with the rhizosphere of cacao as a first step in their application in plant growth promotion and biological control. The populations densities of actinomycetes in soil and cacao roots were similar, with mean values of 1,0 x 10(6) CFU/g and 9,6 x 10(5) CFU/g, respectively. All isolates selected and used in this study were identified through sequencing analyses of a fragment of the rpoB gene that encodes the [beta]-subunit of the RNA polymerase as species of the genus Streptomyces. In vitro cellulolytic, xilanolytic and chitinolytic activity, indolacetic acid production and phosphate solubilization activities were observed in most of the isolates tested. The data obtained in this study demonstrate that actinomycetes account for a higher percentage of the total population of culturable bacteria in soil than on cacao roots. Additionally, actinomycetes from the cacao rhizosphere are genetically diverse and have potential applications as agents of growth promotion.

Apesar da reconhecida importância das bactérias promotoras de crescimento, apenas um reduzido número de estudos foi conduzido com este grupo de microrganismos na cultura do cacaueiro. Os objetivos deste trabalho foram o estudo da densidade populacional e da diversidade genética de actinomicetos associados à rizosfera do cacaueiro como o primeiro passo para sua utilização na promoção de crescimento de mudas desta cultura e no controle biológico de doenças. As densidades populacionais de actinomicetos em amostras de solo e de raízes de cacaueiro foram semelhantes, com valores médios de 1,0 x 10(6) UFC/g e de 9,6 x 10(5) UFC/g, respectivamente. Todos os isolados selecionados para este estudo foram identificados através de análises de seqüências de um fragmento do gene rpoB, que codifica a beta-subunidade da RNA polimerase, como pertencentes ao gênero Streptomyces. Dentre os isolados testados, constatou-se in vitro, a produção de celulase, xilanase, quitinase, ácido indolacético e a capacidade de solubilização de fosfato. Os dados obtidos demonstram que os actinomicetos representam uma maior proporção da população total de bactérias cultiváveis em solo do que em raízes. Adicionalmente, os actinomicetos da rizosfera do cacaueiro são geneticamente diversos e apresentam potencial para atuarem como agentes de promoção de crescimento.

Screening of Low Molecular Metabolite, FS390 as an Inhibitor of Neurotransmitter Release from PC12 Cells / 대한해부학회지

We established an in vitro experimental system using the following procedure. We first introduced tritium-labeled norepinephrine ([3H]-NE) into PC12 cells. The [3H]-NE incorporated-PC12 cells were stimulated by a high concentration (60 mM) of K+ buffer during 12 minutes. Then, we collected 100 microliter supernatant and counted the amount of [3H]-NE release from PC12 cells with a scintillation counter. After screening fungal, Streptomyces spp. or bacterial product using this experimental sytem, we obtained FS390 from Streptomyces spp. which inhibited [3H]-NE release from PC12 cells. FS390 also inhibits the release of ATP as a neurotransmitter of PC12 cells and rat cortical neurons. The inhibitory effect was seen even when the PC12 cells were treated with low K+ buffer containing ionomycin (1 micrometer) as an ionopore. This result suggests that the inhibitory action of FS390 on neurotransmitter release appeared after the influx of Ca2+.