Efeito da qualidade da água no ciclo de vida e na atração para oviposição de Aedes aegypti (L.) (Diptera: Culicidae) / The effect of water quality in the life cycle and in the attraction for the egg oviposition of Aedes aegypti (L.) (Diptera: Culicidae)

The present research aimed at evaluating the influence of the water quality in the life cycle and attraction of Aedes aegypti (L.) females to oviposit using different sources of water (raw sewage, effluent of UASB reactor, effluent of polishing lagoon, effluent of anaerobic filter, rain water and de-chlorinated water). The immature development time and survivorship were evaluated on a daily basis in two distinct feeding systems (with and without food). The quality of the water was shown to affect the egg and larval stages, but not the pupal or the adult. In the absence of food, no development was observed in rain water and de-chlorinated water. Immature development was faster in water sources from raw sewage, although with the lowest survivorship (37.3 percent). Free-choice tests indicated that females preferred to lay most of their eggs on water collected from the effluent of a UASB reactor, achieving the highest oviposition activity index (OAI) of 0.57. In non-choice tests, females laid larger batches of eggs in water collected from anaerobic filters (204.8 eggs), with the lowest number of eggs being laid on de-chlorinated water (37.3 eggs). It can be concluded that A. aegypti does not demonstrate any particular preference to lay eggs on clean water. This has serious implications for developing strategies to manage populations of this important vector in urban areas as it was shown to lay eggs and successfully develop on several different sources of water.

Electroanalytical determination of estriol hormone using a boron-doped diamond electrode.

A boron-doped diamond (BDD) electrode was used for the electroanalytical determination of estriol hormone in a pharmaceutical product and a urine sample taken during pregnancy by square-wave voltammetry. The optimized experimental conditions were: (1) a supporting electrolyte solution of NaOH at a pH of 12.0, and (2) a frequency of 20 Hz, a pulse height of 30 mV and a scan increment of 2 mV (for the square-wave parameters). The analytical curve was linear in the concentration range of 2.0 x 10(-7) to 2.0 x 10(-5) mol L(-1) (r=0.9994), with a detection limit of 1.7 x 10(-7) mol L(-1) and quantification limit of 8.5 x 10(-7) mol L(-1). Recoveries of estriol were in the range of 98.6-101.0%, for the pharmaceutical sample, and 100.2-103.4% for the urine sample, indicating no significant matrix interference effects on the analytical results. The accuracy of the electroanalytical methodology proposed was compared to that of the radioimmunoassay method. The values for the relative error between the proposed and standard methods were -7.29% for the determination of estriol in the commercial product and -4.98% in a urine sample taken during pregnancy. The results obtained suggest a reliable and interesting alternative method for electroanalytical determination of estriol in pharmaceutical products and urine samples taken during pregnancy using a boron-doped diamond electrode.

[The effect of water quality in the life cycle and in the attraction for the egg oviposition of Aedes aegypti (L.) (Diptera: Culicidae)]. / Efeito da qualidade da água no ciclo de vida e na atração para oviposição de Aedes aegypti (L.) (Diptera: Culicidae).

The present research aimed at evaluating the influence of the water quality in the life cycle and attraction of Aedes aegypti (L.) females to oviposit using different sources of water (raw sewage, effluent of UASB reactor, effluent of polishing lagoon, effluent of anaerobic filter, rain water and de-chlorinated water). The immature development time and survivorship were evaluated on a daily basis in two distinct feeding systems (with and without food). The quality of the water was shown to affect the egg and larval stages, but not the pupal or the adult. In the absence of food, no development was observed in rain water and de-chlorinated water. Immature development was faster in water sources from raw sewage, although with the lowest survivorship (37.3%). Free-choice tests indicated that females preferred to lay most of their eggs on water collected from the effluent of a UASB reactor, achieving the highest oviposition activity index (OAI) of 0.57. In non-choice tests, females laid larger batches of eggs in water collected from anaerobic filters (204.8 eggs), with the lowest number of eggs being laid on de-chlorinated water (37.3 eggs). It can be concluded that A. aegypti does not demonstrate any particular preference to lay eggs on clean water. This has serious implications for developing strategies to manage populations of this important vector in urban areas as it was shown to lay eggs and successfully develop on several different sources of water.