RESUMO
The huge biological diversity of the Brazilian Cerrado is an important source of economically interesting microbial agents. The phylum Actinobacteria plays an important role in nutrient cycling, potentially improving their availability to plants. In this study, we isolated an actinobacteria (strain 3AS4) from wheat rhizospheres of crops cultivated in the Cerrado biome. Strain 3AS4 was identified as belonging to the genus Streptomyces and had phosphorus mobilization ability, mineralizing approximately 410 µg ml-1 from phytate, 300 µg ml-1 from calcium phosphate, and 200 µg ml-1 from rock phosphate. The analysis of the actinobacteria crude extract by spectrometric techniques revealed the presence of gluconic and 2-ketogluconic acid, and a greenhouse experiment was carried out to evaluate its plant growth promotion activity in soybean. Soil in its natural condition (with no phosphorus addition), 40 kg ha-1 rock phosphate from Bayovar (RP) added to soil, and triple super phosphate (SPT) added to soil were used. Significant differences in plant height were observed at 6 weeks when the plants were inoculated with the 3AS4 strain. The growth of inoculated plants in natural condition was promoted in 17% compared with the RP and SPT non-inoculated conditions, suggesting that inoculation can enable plants to grow with lower chemical P fertilizers. In the plants that were inoculated with the 3AS4 strain in the RP condition, the plant height increased by approximately 80% and the shoot:root ratio was approximately 30% higher compared to control conditions (non-inoculated plants in natural conditions). 3AS4 has P-solubilizing potential and can be exploited as an inoculant for soybean cultivation. These results suggest that this actinobacterium is a valuable resource for sustainable agriculture and will allow the reduction of phosphate fertilization in the future.
RESUMO
Ehrlichiosis is a worldwide illness, endemic in tropical and subtropical countries where seroprevalence can reach up to 33% as it is the case in México and Israel. However, the low sensitivity of the serological tests used for diagnosis, 67% in tests with IFI, has led to a required searching for new alternatives to diagnose the disease quickly and effectively. PCR is one of these techniques that could provide high sensitivity and specificity. The target of this study was to implement the PCR test for the diagnosis of Ehrlichia spp., on blood samples from animals with suspected illness from veterinary clinics in the city of Medellin. 90 samples were taken, 33 samples from animals suspected of having symptoms and 57 from healthy animals as probable negatives. DNA from the Madrid strain was used as a positive control. The PCR was performed using as an example the protocol suggested by Aguirre et al (2004). EEC and ECB primers reported by Dawson et al (2004) were used (aquí el propio texto en español no está claro). In this study the 500pb band was amplified, corresponding to the 16s rRNA of Ehrlichia spp., in 11 samples of the animals with suspected illness, obtaining a presentation rate of 33.3%, confirming the presence of bacteria in the animals of the environment, and achieving the implementation of PCR for Ehrlichia spp. as a diagnostic tool in the city.
La Ehrlichiosis es una enfermedad de distribución mundial, es endémica en los países tropicales y subtropicales en donde la seroprevalencia puede llegar a ser hasta del 33%, como en México e Israel. La baja sensibilidad de las pruebas utilizadas para el diagnóstico, 67% en las pruebas con IFI, han llevado a la necesidad de buscar nuevas alternativas que permitan diagnosticar la enfermedad de manera rápida y eficaz. La PCR es una de estas técnicas que podría ofrecer una alta sensibilidad y especificidad. El objetivo de este trabajo fue implementar la prueba de PCR, para el diagnóstico de Ehrlichia spp., en muestras de sangre de caninos sospechosos provenientes de consultorios veterinarios de la ciudad de Medellín. Se tomaron 90 muestras, 33 de animales sospechosos de ehrlichiosis por sintomatología, y 57 de animales sanos como probables negativos. Se utilizó como control positivo el ADN de la cepa Madrid. La PCR fue realizada utilizando como ejemplo el protocolo sugerido por Aguirre et al. (2004). Se utilizaron los primers EEC y ECB reportados por Dawson et al. (1994). En este estudio se logró amplificar la banda de 500 pb correspondientes al gen 16s ARNr de Ehrlichia spp., en 11 muestras de los animales sospechosos, obteniendo una frecuencia de presentación del 33,3%, confirmando la presencia de la bacteria en los animales de nuestro medio, y logrando la implementación de PCR para Ehrlichia spp. como herramienta diagnóstica en nuestra ciudad.
A ehrlichiose é uma doença em todo o mundo, é endêmica em países tropicais e subtropicais, onde a soroprevalência pode atingir até 33%, como no México e Israel. A baixa sensibilidade dos testes utilizados para o diagnóstico, 67% nos testes de IFI, levaram à necessidade de buscar novas formas de diagnosticar a doença de forma rápida e eficaz. PCR é uma técnica de tal forma que poderia fornecer alta sensibilidade e especificidade. O objetivo deste trabalho foi implementar o teste de PCR para o diagnóstico de Ehrlichia spp., Em amostras de sangue de cães suspeitos de clínicas veterinárias da cidade de Medellín. Demorou 90 amostras, 33 amostras de suspeitos que apresentavam sintomas de erliquiose e 57 animais saudáveis como negativo provável. Foi utilizado como controle positivo de ADN a partir da estirpe de Madrid. A PCR foi padronizada utilizando o exemplo do protocolo proposto por Aguiar et al. (2004). Utilizou-se primers BCE CES e relatado por Dawson et al. (1994). Neste estudo foram amplificados de banda de 500 pb para o gene 16S rRNA do gênero Ehrlichia em 11 amostras de animais suspeitos, a obtenção de uma taxa de apresentação de 33,3%, o que confirma a presença de bactérias em animais nosso meio ambiente e obter a implementação de PCR por Ehrlichia spp. como uma ferramenta de diagnóstico em nossa cidade.
