Response to chemotherapy with benznidazole of clones isolated from the 21SF strain of Trypanosoma cruzi (biodeme Type II, Trypanosoma cruzi II) Resposta à quimioterapia com benzonidazol de clones isolados da cepa 21SF do Trypanosoma cruzi (biodema Tipo II, Trypanosoma cruzi II)

Susceptibility to chemotherapy with benznidazole was investigated of 5 clones isolated from the 21 SF strain (biodeme Type II, Trypanosoma cruzi II). Swiss mice were infected with the parental strain for each clone and submitted to chemotherapy with benznidazole (100mg/kg/day during 90 days). Treatment determined negativity of the parasitemia. Cure rates were evaluated by parasitological cure tests. Serology was evaluated for treated animals (titers from negative to 1:640) and untreated controls (1:160 to 1:640). Cure rates varied from 30 to 100% for the 5 clones, and were 25% for the parental strain. Results suggested that the variability of response to treatment of the clonal populations of Trypanosoma cruzi II strains is responsible for the high variation in the response to chemotherapy with benznidazole and nifurtimox by strains of this biodeme.<br>A suscetibilidade à quimioterapia com o benzonidazol, de 5 clones isolados da cepa 21SF (biodema Tipo II, T. cruzi II), foi investigada. Camundongos suíços foram infectados com a cepa parental e com cada clone e submetidos à quimioterapia com benzonidazol (100mg/k/dia durante 90 dias). Os índices de cura foram avaliados pelos testes de cura parasitológicos. A sorologia foi avaliada para os animais tratados e (de negativo a 1: 640) e para os controles não tratados( 1:160 a 1:640). Os índices de cura variaram de 30% a 100% para os 5 clones sendo de 25% para a cepa parental. Os resultados sugerem que a variabilidade de resposta ao tratamento das populações clonais das cepas Trypanosoma cruzi II é responsável pela grande variação na resposta à quimioterapia com benzonidazol e nifurtimox das cepas deste biodema

IBA AND MICROCUTTING COLLECTIONS IN THE MICROPROPAGATION OF Eucalyptus spp HYBRID CLONES.1

ABSTRACT This study aims to evaluate the effect of IBA concentrations and microcuttings successive collections in the micropropagation of Eucalyptus grandis x E. urophylla and Eucalyptus urophylla x E. globulus clones. Clumps containing six to eight buds of clones established in vitro were transferred to a 250 mL glass flask in JADS semisolid medium. Successive collections were performed every 20 days for Eucalyptus grandis x E. urophylla clone and every 30 days for Eucalyptus urophylla x E. globulus clone. The following variables were evaluated under in vitro conditions: number of shoots > 0.5 cm, number of microcuttings > 2 cm, length of the longest microcutting, and shoots vigor. Under ex vitro conditions, in the greenhouse and shade house, the following variables were evaluated: seedling height, percentage of survival, stem diameter, percentage of root observed at the lower end of the tube, and seedling vigor. In full sun (ex vitro), the following variables were analyzed: seedling height, stem diameter, survival, number of roots, root volume, seedling vigor, and shoot and root dry matter. Good in vitro microcuttings productivity was observed over the successive collections. IBA levels were adjusted for each clone, ranging from 0.25 to 0.50 mg L-1 for Eucalyptus grandis x E. urophylla clone, and from 0.75 to 1.0 mg L-1 for Eucalyptus urophylla x E. globulus clone. IBA concentrations led to residual effects under ex vitro conditions, providing good rooting and survival for Eucalyptus grandis x E. urophylla and Eucalyptus urophylla x E. globulus clones at IBA concentrations between 0.25 and 0.50 mg L-1 and between 0.50 and 1.0 mg L-1, respectively