Condiciones para el desarrollo de Beauveria bassiana y Metarhizium anisopliae para el control biológico de chapulín frijolero

El chapulín frijolero (Brachystola magna Girard), es un problema en la zona temporalera del estado de Chihuahua, ya que afecta más del 60 % de la superficie sembrada anualmente. Para su control se emplean insecticidas organofosforados y cebos envenenados (CESAVECH, 2001); sin embargo, su uso excesivo ha provocado resistencia de la plaga, acumulación de residuos en el medio ambiente y daños a la flora y fauna silvestre benéfica. Como una alternativa de control biológico se considera el uso de organismos benéficos, que pueden ser incorporados al manejo integrado de plagas, sin efectos nocivos para el medio ambiente y la salud del hombre y los animales (Jiménez 1998). En este trabajo se estudiaron las condiciones óptimas (medio de cultivo, luz y temperatura) para el desarrollo de los aislamientos nativos de hongos entomopatógenos Beauveria bassiana (Bb001) y Metarhizium anisopliae (Ma002), con el fin de utilizarlas en la regulación de la población del chapulín frijolero. Los aislamientos se evaluaron en siete medios de cultivo y siete temperaturas. La mayor esporulación se observó en el medio SDAY. El aislamiento Bb001 mostró el mayor crecimiento en AHM. El crecimiento y esporulación fueron mayores bajo oscuridad continua y a una temperatura de 25 °C. Por otro lado, Ma002 mostró mayor crecimiento en SDA, mayor crecimiento en oscuridad continua, mayor esporulación con luz continua y la temperatura óptima fue de 30 °C. Los resultados mostraron que pueden controlarse adecuadamente las variables ambientales en el laoboratorio, para la reproducción de los hongos B. bassiana (Bb001) y M. anisopliae (Ma002), aislamientos prometedores como una alternativa de control biológico. Abstract The bean grasshopper (Brachystola magna Girard) is a problem in the temporal zone of Chihuahua, because affects above 60 % of the annually sown surface. Organophosphate insecticides and poisoned baits are used to control this insect (CESAVECH, 2001); however, their excessive use has led to pesticide resistance, residues accumulation in the environment affecting beneficial wild flora and fauna. The use of benefical organisms is an alternative of biological control to be incorporated in any integrated pest management. It does not have effects to the environment, nor produce damage on health of men and animals (Jiménez, 1998). In this research, the environmental conditions were studied (culture medium, light and temperature effect), which are suitable for the development of native isolates of entomopathogenic fungus Bauveria bassiana (Bb001) y Metarhizium anisopliae (Ma002). The environmental control is important to regulate growth of bean grasshopper population in temporal region of Chihuahua state. The isolates were evaluated in seven culture mediums and seven temperatures. The greatest isolates sporulation was observed in SDAY. The isolate Bb001 had the best growth in AHM. Isolates growth and sporulation were better under continuos darkness and at 25 °C temperature. On the other hand, Ma002 showed the best growth in SDA, and under continuos darkness; however, the highest sporulation was observed under continuos light and at 30 °C temperature. The results demostrated that lab environmental variables can be controled for growth and development of entomopathogenic fungus B. bassiana and M. anisopliae, which are promising isolates as an alternative of biological control. Keywords: Entomopathogenic fungus, biological control, beneficial organisms, culture mediums, Brachystola magna, bio insecticides

Effect of the Melanocortin 4-Receptor Ile269Asn Mutation on Weight Loss Response to Dietary, Phentermine and Bariatric Surgery Interventions

The loss of function melanocortin 4-receptor (MC4R) Ile269Asn mutation has been proposed as one of the most important genetic contributors to obesity in the Mexican population. However, whether patients bearing this mutation respond differently to weight loss treatments is unknown. We tested the association of this mutation with obesity in 1683 Mexican adults, and compared the response of mutation carriers and non-carriers to three different weight loss interventions: dietary restriction intervention, phentermine 30 mg/day treatment, and Roux-en-Y gastric bypass (RYGB) surgery. The Ile269Asn mutation was associated with obesity [OR = 3.8, 95% CI (1.5–9.7), p = 0.005]. Regarding interventions, in the dietary restriction group only two patients were MC4R Ile269Asn mutation carriers. After 1 month of treatment, both mutation carriers lost weight: −4.0 kg (−2.9%) in patient 1, and −1.8 kg (−1.5%) in patient 2; similar to the mean weight loss observed in six non-carrier subjects (−2.9 kg; −2.8%). Phentermine treatment produced similar weight loss in six carriers (−12.7 kg; 15.5%) and 18 non-carriers (−11.3 kg; 13.6%) after 6 months of pharmacological treatment. RYGB also caused similar weight loss in seven carriers (29.9%) and 24 non-carriers (27.8%), 6 months after surgery. Our findings suggest that while the presence of a single MC4R loss of function Ile269Asn allele significantly increases obesity risk, the presence of at least one functional MC4R allele seems sufficient to allow short-term weight loss in response to dietary restriction, phentermine and RYGB. Thus, these three different interventions may be useful for the short-term treatment of obesity in MC4R Ile269Asn mutation carriers