Reassessment of the vocal repertoire of a nest-building gladiator frog,Boana pardalis (Anura,Hylidae, Cophomantinae): implications for its diagnosis within the B. faber species group

In this study, we re-describe the advertisement and territorial calls of Boana pardalis, carry out an acoustic comparison between the studied species and the other congeners of the B. faber group, and report for the first time the tympanic amplexus for the studied species. The advertisement call of B. pardalis can be used to supplement its diagnosis in the B. faber group based on temporal call traits, e.g. emission rate and emission pattern, as well as the call envelope.     

Tactical Voting in Plurality Elections

How often will elections end in landslides? What is the probability for a head-to-head race? Analyzing ballot results from several large countries rather anomalous and yet unexplained distributions have been observed. We identify tactical voting as the driving ingredient for the anomalies and introduce a model to study its effect on plurality elections, characterized by the relative strength of the feedback from polls and the pairwise interaction between individuals in the society. With this model it becomes possible to explain the polarization of votes between two candidates, understand the small margin of victories frequently observed for different elections, and analyze the polls'' impact in American, Canadian, and Brazilian ballots. Moreover, the model reproduces, quantitatively, the distribution of votes obtained in the Brazilian mayor elections with two, three, and four candidates.     

Identification of UDP-linked murein precursors as contaminants in recombinant proteins of low molecular weight.

The A(280)/A(260) ratio of a purified protein is frequently used as an indication of the purity of the preparation with respect to nucleic acids. We show here that for low-molecular-weight recombinant proteins purified from Escherichia coli, a low A(280)/A(260) ratio can also result from contamination with UDP-linked murein precursors derived from bacterial cell wall metabolism. Although these precursors are small molecules of molecular weight 1000-1200, they comigrate in gel filtration with recombinant human FKBP (MW 11,820). This gel filtration behavior, which is distinct from that of unmodified mononucleotides, does not reflect binding interactions with FKBP, but is an intrinsic property of these precursors. Therefore, these molecules would be expected to copurify with other low-molecular-weight proteins, especially in the abbreviated purification protocols made possible by freeze-thaw release of recombinant proteins from E. coli (Johnson, B. H., and Hecht, M. H. (1994) BioTechnology 12, 1357-1360). Several alternative strategies are discussed for integrating these findings into the design of improved purification procedures for low-molecular-weight recombinant proteins.     

Influence of Trypanosoma cruzi strain on the pathogenesis of chronic myocardiopathy in mice

The murine model of chronic Chaga's myocardiopathy was developed in 201 inbred and outbred mice. The experimental groups consisted of 1st: 73 inbred AKR and A/J mice inoculated with one of the following Trypanosoma cruzi strains: Peruvian (Type I), 12 SF (Type II) or Colombian (Type III); 2nd: 128 outbred Swiss mice, chronically infected either with Type II or Type III strains isolated from human patients from different geographical areas. All T. cruzi strains were previously characterized by their morphobiological behaviour in mice and by isoenzymatic patterns. For the 1st group the inoculum was 5 x 10(4) for the Peruvian strain and 1 x 10(5) for the 12 SF and Colombian strains. In the 2nd group-Swiss mice the inoculum size varied from 2 x 10(4) to 2 x 10(5). The inbred animals were killed at a 3 time-point scale (90, 180 and 240 days) post-infection. The Swiss mice were killed from 180 to 660 days after infection. The evaluation of parasitemia and serology (xenodiagnosis and indirect immunofluorescent test) was performed. The incidence of macroscopic alterations of the heart and cardiac index were evaluated. Histopathological lesions of the myocardium were graded. The influence of T. cruzi strain on the intensity of cardiac lesions was evaluated by the Chi-square test; the incidence of inflammatory lesions and its relationship to the parasite strain was evaluated by the Fisher test. The influence of the duration of infection was evaluated by using the Gamma Coefficient of Kruskal and Goodman and its measure of significance. Slight to severe microscopic alterations occurred in 85% of the chronically infected mice. There were a clear predominance on the incidence and intensity of inflammatory and fibrotic alterations for the mice infected with Type III strains. Statistical analysis has shown significant differences among the infected groups, in the inflammatory and fibrotic lesions. Macroscopic alterations (right cavities dilatation and apex aneurism of left ventricle), differed in incidence according to mice strains; in Swiss and AKR mice, significant differences were seen in mice infected with different T. cruzi strains, but the A/J mice failed to show significant differences correlated with different parasite strains. The duration of infection, from 90 to 240 days, could not be correlated with the degree of lesions in the several groups.