Browsing by Author "Ribeiro, Tatiana Gomes"

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    Antileishmanial activity of compounds produced by endophytic fungi derived from medicinal plant Vernonia polyanthes and their potential as source of bioactive substances.
    (2015) Nascimento, Adriana Mendes do; Soares, Mateus Gonçalves; Torchelsen, Fernanda Karoline Vieira da Silva; Araújo, Jorge Augusto Viana de; Lage, Paula Souza; Duarte, Mariana Costa; Andrade, Pedro Henrique Rocha de; Ribeiro, Tatiana Gomes; Coelho, Eduardo Antônio Ferraz; Nascimento, Andréa Mendes do
    The purpose of this work was to evaluate the antileishmanial activity of endophytic fungi isolated from leaves of Vernonia polyanthes plant and their prospective use in the discovery of bioactive compounds. Sixteen endophytes were isolated by using potato dextrose agar medium and submitted to cultivation in rice medium. The fungal cultures were extracted with ethanol and used as crude extracts for testing their antileishmanial activity. The most active ethanol extract was obtained from P2-F3 strain, which was identified as Cochliobolus sativus by ITS rRNA gene sequence data. Followed by a bioassay-guided fractionation, the cochlioquinone A, isocochlioquinone A and anhydrocochlioquinone A compounds were isolated from the crude extracts and demonstrated to inhibit the parasites. From the present work, it is possible to conclude that endophytic fungi derived from medicinal plant V. polyanthes may be considered promising source for the discovery of bioactive compounds.
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    Sensitive and specific serodiagnosis of Leishmania infantum infection in dogs using peptides selected from hypothetical proteins identified by an immunoproteomic approach.
    (2013) Chávez Fumagalli, Miguel Angel; Martins, Vívian Tamietti; Testasicca, Miriam Conceição de Souza; Lage, Daniela Pagliara; Costa, Lourena Emanuele; Lage, Paula Souza; Duarte, Mariana Costa; Ker, Henrique Gama; Ribeiro, Tatiana Gomes; Carvalho, Fernando A. A.; Régis, Wiliam César Bento; Reis, Alexandre Barbosa; Tavares, Carlos Alberto Pereira; Soto, Manuel; Fernandes, Ana Paula; Coelho, Eduardo Antônio Ferraz
    In Brazil, the percentage of infected dogs living in areas where canine visceral leishmaniasis (CVL) is endemic ranges from 10 to 62%; however, the prevalence of infection in dogs is probably higher than figures reported from serological studies. In addition, problems with the occurrence of false-positive or false-negative results in the serodiagnosis of CVL have been reported. The present work analyzed the potential of synthetic peptides mapped from hypothetical proteins for improvement of the serodiagnosis of Leishmania infantum infection in dogs. From 26 identified leishmanial proteins, eight were selected, considering that no homologies between these proteins and others from trypanosomatide sequence databases were encountered. The sequences of these proteins were mapped to identify linear B-cell epitopes, and 17 peptides were synthesized and tested in enzyme-linked immunosorbent assays (ELISAs) for the serodiagnosis of L. infantum infection in dogs. Of these, three exhibited sensitivity and specificity values higher than 75% and 90%, respectively, to differentiate L. infantum-infected animals from Trypanosoma cruziinfected animals and healthy animals. Soluble Leishmania antigen (SLA) showed poor sensitivity (4%) and specificity (36%) to differentiate L. infantum-infected dogs from healthy and T. cruzi-infected dogs. Lastly, the three selected peptides were combined in different mixtures and higher sensitivity and specificity values were obtained, even when sera from T. cruzi-infected dogs were used. The study’s findings suggest that these three peptides can constitute a potential tool for more sensitive and specific serodiagnosis of L. infantum infection in dogs.