RESUMO
Koinobiont parasitoids use several strategies to regulate the host's physiological processes during parasitism. Although many aspects of host-parasitoid interactions have been explored, studies that attempted to assess the effects of parasitism on the availability of inorganic elements in the host are virtually nonexistent. Therefore, we aimed to evaluate the effects of parasitism on the concentrations of inorganic elements in the fat bodies of larvae of Diatraea saccharalis (Lepidoptera: Crambidae) during the development of the parasitoid Cotesia flavipes (Hymenoptera: Braconidae), by using total reflection X-ray fluorescence (TXRF). TXRF analysis allowed comparisons of the changes in the availability of the elements P, S, K, Ca, Cr, Fe, Ni, Cu, and Zn in the fat body tissues of D. saccharalis larvae parasitized by C. flavipes. Overall, the concentration of inorganic elements was higher early in parasitoid development (1 and 3days after parasitism) compared to non-parasitized larvae, but much lower towards the end of parasitoid development (7 and 9days after parasitism). Ca, K, and S were reduced after the fifth day of parasitism, which affected the total abundance of inorganic elements observed in the fat bodies of the parasitized hosts. The regulatory mechanisms or pathological effects related to the observed variation of the host inorganic elements induced by the parasitoid remain unknown, but there might be a strategy to make these elements available to the parasitoid larvae at the end of their development, when higher metabolic activity of the host fat body is required to sustain parasitoid growth. The observed variation of the host's inorganic elements could also be related to the known effects of parasitism on the host's immune response.
Assuntos
Elementos Químicos , Corpo Adiposo/química , Himenópteros/fisiologia , Lepidópteros/parasitologia , Animais , Larva/química , Larva/parasitologia , Lepidópteros/químicaRESUMO
Analysis of bacterial plasmid profiles has been shown to be very important in epidemiological studies, especially those involving outbreaks of nosocomial infections. The molecular weight size of unknown plasmids is determined by comparing their band pattern obtained in agarose gel electrophoresis with those obtained with plasmids that have been used as molecular weight or size standards. In this study, we determined the size of plasmids present in clinical samples of Enterobacter cloacae comparing their electrophoresis mobility with seven plasmids of known size, using three different mathematical methods. For plasmids with molecular weight ranging from 2 kb to 100 kb. The most accurate determinations were obtained by power-function. Analyses using the exponential variables obtained with these plasmids were accurate for two types of plasmids, those with size ranging from 50 kb to 100 kb and those with size ranging from 2 kb to 30 kb. We also observed discrepancies among the methodologies described, including one used by a computer software designed for calculating the size of plasmids DNA.