Physiological aspects of Trypanosoma cruzi gene regulation during heat-shock

Investigations on the conditions of heat-shock response in Trypanosoma cruzi, the agent of Chagas disease, showed that at 37 degrees C, one of the heat-shock temperatures employed, the parasites from 48 h culture do not display a classical response to the heat treatment, since a general increase in RNA and protein synthesis was detected. The classical heat-shock response was detected only at 40 degrees C. The data also suggest that the heat shock proteins (HSP) mRNA population is sufficient to maintain protein synthesis at a high rate for at least 1 h and, to maintain the same rate of response for a longer period, transcription is necessary. The half life of HSP 70 mRNA is less than 3 h at 37 degrees C. The protein synthesized during the first hour of the heat shock at 37 degrees C is stable for at least 24 h. The parasite seems to be able to reuse the stock of HSP mRNAs stored during the first thermal shock to respond to a second heat treatment. These data are discussed bearing in mind other cell types

Comparison of Rio de Janeiro DNA typing data with the FBI worldwide study

We analyzed 128 chromosomes for the D4S139 (pH30) locus and determined the allelic frequency of our sampling using the 31 fixed-bin key table. Using the frequency distribution of this locus in the different population database available, we compared our sample with eight distinct populations through scatter plot. Our result corroborates the notion that, in forensic science, there is no significant difference among polulations. We also typed 12 different individuals for four loci (D4S139, D1S7, D10S28, D2S44) and 3 profiles of three loci (D4S139, D1S7, D10S28). Individual genotype frequency was determined for each population. Whatever reference population database used, the result showed that each person has a very genotype frequency, ranging from 10E-11 to 10E-13, for four loci typing, and from 10E-07 to 10-E10, for three loci typing. As stated before, these results indicate that the statistical differences found among populations do not interfere in forensic science application and therefore, the use of a general population database will not produce a biased result.