Comparison of the partial DNA sequence of the 16S rRNA gene of Anaplasma platys detected in dogs from Ribeirão Preto, Brazil, to sequences of other strains previously deposited in GenBank showed that there are at least three A. platys strains circulating in South America.

The partial DNA sequences of the 18S rRNA gene of Babesia canis and the 16S rRNA gene of Ehrlichia canis detected in dogs from Ribeirão Preto, Brazil, were compared to sequences from other strains deposited in GenBank. The E. canis strain circulating in Ribeirão Preto is identical to other strains previously detected in the region, whereas the subspecies Babesia canis vogeli is the main Babesia strain circulating in dogs from Ribeirão Preto.

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HERNANDES, C.; CARDOZO, G.P.; FRANÇA, S.C.; FACHIN, A.L.; MARINS, M.*; LOURENÇO, M.V.Universidade de Ribeirão Preto, UNAERP, CEP: 14096-900, Ribeirão Preto-Brasil *marins@heranza.com.br ABSTRACT: Cancer is one of the leading causes of death in dogs, a fact that has boosted the investigation for new more specific antitumor drugs. This study evaluated the antitumor activity of jasmonates in the canine macrophage cell line DH82 (ATCC # CRL-10389) isolated from a case of malignant histiocytoma. The activities of methyl jasmonate and jasmonic acid were compared to that of doxorubicin by the MTT assay. Methyl jasmonate resulted in the highest inhibition of cell growth (82.2%), followed by doxorubicin (80.7%) and jasmonic acid (36.5%). More detailed studies regarding the action of jasmonates on animal health are necessary, but the present results indicate methyl jasmonate as an alternative to the development of drugs for the treatment of canine oncologies. Key words: jasmonates, histiocytoma, dogsRESUMO: Efeito citotóxico de jasmonato e metiljasmonato em linhagem tumoral celular de macrófagos caninos. O câncer é uma das principais causas de morte em cães o que tem impulsionado a pesquisa por novos antitumorais com ação mais específica. Neste trabalho, a atividade antitumoral de jasmonatos foi avaliada na linhagem de macrófagos caninos DH82 (ATCC # CRL-10389), a qual é originada de um caso de histiocitoma maligno. A atividade do metil jasmonato (MJ) e do ácido jasmônico (AJ) foram comparadas à doxorrubicina, através do método de coloração MTT. O MJ apresentou maior inibição (82,2%), seguido da Doxorrubicina (80,7%) e AJ (36,5%). Estudos mais completos da ação dos jasmonatos na saúde animal ainda são necessários, porém, os dados deste trabalho apontam o MJ como alternativa para o desenvolvimento de drogas para o tratamento das oncologias caninas.

ABSTRACT. Two-component signal transduction systems (TCS) are important elements in the interaction of endobacteria with host cells. They are basically composed of two proteins, an environmental signal sensor and a response regulator, which activate genes involved in a wide range of bacterial responses to their environment. We analyzed three sets of genes corresponding to TCS of Ehrlichia canis, a common tick-borne canine pathogen and the etiologic agent of canine monocytic ehrlichiosis, in order to identify the characteristic domains of the sensor and response regulator components. Analysis of sequence alignments of the corresponding proteins indicated a high degree of similarity to other members of the Anaplasmataceae TCS proteins, demonstrating that they could be useful as universal targets for development of new drugs against these bacteria. We also evaluated by quantitative PCR inhibition of E. canis by (2H)-1,4-benzoxazin-3(4H)-one (BOA), the core compound of the plant phenolic compound DIMBOA, which shows inhibitory action against TCS of the phytopathogen Agrobacterium tumefasciens. This bacterium exerts its pathogenicity ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 11 (4): 3576-3584 (2012) TCS of Ehrlichia canis 3577by transferring oncogenic DNA (T-DNA) into plant cells; this transfer is mediated through a type-IV secretion system, which is regulated by the VirA/VirG TCS. The process of infection and pathogenesis of E. canis is associated with the secretion of effector proteins into the host cell cytoplasm through a T4SS system, which blocks the cell defense response. We suggest that BOA, and possibly other plant phenolic compounds that are TCS inhibitors, can be exploited in the search for new antiehrlichial drugs to be used alone or as complements in the treatment of canine monocytic ehrlichiosis.