| Autor: |
Benito N; Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico, Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601, 5800, Río Cuarto, Córdoba, Argentina.; FONCYT (Fondo para la Investigación Científica y Tecnológica), Buenos Aires, Argentina., Carranza CS; Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico, Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601, 5800, Río Cuarto, Córdoba, Argentina.; CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas), Buenos Aires, Argentina., Magnoli CE; Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico, Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601, 5800, Río Cuarto, Córdoba, Argentina.; CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas), Buenos Aires, Argentina., Barberis CL; Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico, Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601, 5800, Río Cuarto, Córdoba, Argentina. barberiscorreo@gmail.com.; CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas), Buenos Aires, Argentina. barberiscorreo@gmail.com. |
| Abstrakt: |
Atrazine is one of the most frequently used herbicides in Argentina for controlling broadleaf weeds and annual grasses. Currently, there is limited information on the impact of triazine herbicides on mycotoxin production and growth parameters of toxigenic fungi in maize. The objective of this study was to evaluate the effect of different concentrations of atrazine on the lag phase prior to growth, the growth rate, and on production of aflatoxin B 1 (AFB 1 ) of Aspergillus flavus and Aspergillus parasiticus strains, on maize meal extract agar (MMEA) under different water activities (a W ) and temperatures. A commercial formulation of atrazine was added to MMEA medium at 0, 5, 10, 50, or 100 mmol/l, adjusted to 0.98, 0.95, and 0.93 a W , and incubated at 28 °C and 37 °C for 21 days. AFB 1 was determined by HPLC after 7, 14, and 21 days of incubation. In the control treatments, a significant increase in the time prior to growth was observed and as the a W decreased, at both temperatures, the growth rate of the strains also decreased. A significant increase in growth rate was observed as the concentration of atrazine in the medium increased, for all a W levels tested. The optimal conditions for the accumulation of AFB 1 in the control treatments were 0.98 a W and 28 °C, after 7 days of incubation. As the concentration of herbicide increased, AFB 1 production also increased (P < 0.05). These results add to the knowledge about consequences with regard to aflatoxin production of the use of excessive atrazine doses in extensive maize culture. |
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