Daniel Thompsen Passos

Mitochondrial and nuclear DNA analyses reveal population differentiation in Brazilian Creole sheep.

Using ND5 sequences from mtDNA and 10 nuclear markers, we investigated the genetic differentiation of two South American Creole sheep phenotypes that historically have been bred in different biomes in southern Brazil. In total, 18 unique mtDNA haplotypes were detected, none of which was shared between the two phenotypes. Bayesian analysis also indicated two different groups (k = 2). Thus, these varieties are supported as being genotypically distinct. This situation could have resulted either from geographical isolation, associated with differences in the cultural habits of sheep farmers and in the way that flocks were managed, or more likely, from the introduction of different stocks four centuries ago.

Isolamento de Salmonella Braenderup em arara-azul (Anodorhynchus hyacinthinus)

The sanitary monitoring of free-living Hyacinth macaw (Anodorhynchus hyacinthinus) allows adjusting the management in altered natural habitat. To evaluate the occurrence of Salmonella spp. it was collected cloacal swabs of this nestlings species, in the Pantanal wetlands, in the state of Mato Grosso do Sul, Brazil. One Salmonella-like colony was serologically typed and identified as Salmonella Braenderup. Due to the high zoonotical potential of this microorganism, it is important an effective sanitary control of wildlife psittacines. In the literature searched it was not found any report on isolation of this bacterium in Hyacinth macaw for both free-living and captive animals.

Inhibition of MDR1 expression by retinol treatment increases sensitivity to etoposide (VP16) in human neoplasic cell line.

Multidrug resistance (MDR) is the major obstacle to cancer chemotherapy. MDR phenotype is mainly related to the over-expression of MDR1 gene, being responsible for tumor resistance to several chemotherapeutic drugs. It has been suggested that MDR1 expression is redox-regulated and we have recently described a pro-oxidative effect of retinol. Here we tested the therapeutic use of retinol as a modulator of MDR1 gene expression in tumor cell lines, and verified in situ the enhancement of anticancer drug efficacy. Two human colorectal adenocarcinoma cell lines (HT29, SW620) with different degrees of MDR1 expression were used. Cells were pre-treated with a sublethal dose of retinol and then challenged with the etoposide (VP16) drug. The drug GI50 was assessed by SRB method and levels of MDR1 expression were determined by semi-quantitative rtPCR. Retinol treatment caused a 40% decrease in MDR1 expression and increased VP16 toxicity. MDR1 expression and drug sensitivity were restored to control values when mannitol (a hydroxyl radical scavenger) was co-administrated. Our data point a role to the use of retinol as an adjuvant in the treatment of tumors with MDR phenotype.