Validation of a reaction volume reduction protocol for analysis of Y chromosome haplotypes targeting DNA databases

The use of Y chromosome haplotypes, important for the detection of sexual crimes in forensics, has gained prominence with the use of databases that incorporate these genetic profiles in their system. Here, we optimized and validated an amplification protocol for Y chromosome profile retrieval in reference samples using lesser materials than those in commercial kits. FTA^® cards (Flinders Technology Associates) were used to support the oral cells of male individuals, which were amplified directly using the SwabSolution reagent (Promega). First, we optimized and validated the process to define the volume and cycling conditions. Three reference samples and nineteen 1.2 mm-diameter perforated discs were used per sample. Amplification of one or two discs (samples) with the PowerPlex^® Y23 kit (Promega) was performed using 25, 26, and 27 thermal cycles. Twenty percent, 32%, and 100% reagent volumes, one disc, and 26 cycles were used for the control per sample. Thereafter, all samples (N = 270) were amplified using 27 cycles, one disc, and 32% reagents (optimized conditions). Data was analyzed using a study of equilibrium values between fluorophore colors. In the samples analyzed with 20% volume, an imbalance was observed in peak heights, both inside and in-between each dye. In samples amplified with 32% reagents, the values obtained for the intra-color and inter-color standard balance calculations for verification of the quality of the analyzed peaks were similar to those of samples amplified with 100% of the recommended volume. The quality of the profiles obtained with 32% reagents was suitable for insertion into databases.

First forensic records of termite activity on non-fossilized human bones in Brazil

The aim of this study was to describe the first records of termite activity on non-fossilized human bones in Brazil. The cases reported in this study resulted from forensic analysis of six human skeletons found in northeastern Brazil between 2012 and 2014. Traces of tunnels and nests commonly produced by termites were found on several human bone surfaces as well as the specimens and characteristic signs of osteophagic activity. In four cases, the species were identified: Amitermes amifer Silvestri, 1901, Nasutitermes corniger (Motschulsky, 1855) (on two skeletons), and Microcerotermes indistinctus Mathews, 1977. In two other cases, the activity of termites on bone surfaces was evidenced by remains of nests and tunnels produced by these insects. At least in the samples of human remains available for this report, the number of termites collected was greater on bones found during autumn, the rainy season in the Northeast of Brazil. The human bones examined showed termites like insects with lots of strength at bone degradation, capable of continuing the process of decomposition of human remains even in completely skeletonized bodies.

The temperature of water ingested ad libitum does not influence performance during a 40-km self-paced cycling trial in the heat

AIM

The aim of the present study was to evaluate the effects of the temperature of ingested water on performance during a 40-km self-paced cycling trial in the heat (35º C and 60% relative humidity).

METHODS

The study was randomized, counterbalanced, crossover and single-blinded. Ten well-trained male cycling athletes (cyclists, mountain bikers or triathletes) who were non-acclimatized to heat were subjected to four experimental situations divided into two sets. In the first set, the participants performed two trials, during which they were given either cold (10º C) or warm water (37º C) ad libitum. In these situations, the volume and timing of the water ingestion (when each bolus was ingested) were recorded and replicated in the second set, but the water temperature was reversed.

RESULTS

The performance times were unaffected by the water intake volume (P=0.425), but the water at a temperature of 37º C tended to induce lower performance times (P=0.078) during the trials (AL10=93.0±3.5 min; AL37=94.4±4.1 min; SC10=93.4±4.0; SC37=97.4±4.3 min). The water intake was greater when the water was cold (P<0.05), but the temperature did not affect the heat storage rate, rectal temperature, mean skin temperature, heart rate, blood glucose level, sweat loss, sweat rate, perceived exertion rate or plasma volume changes. However, a significant reduction in the plasma volume change from pre- to postexercise was observed (P<0.01).

CONCLUSION

The performance, thermoregulatory, cardiovascular and metabolic responses during a 40-km self-paced cycling trial in the heat were unaffected by different water temperatures.