RESUMO
A recent paper by Beretta-Blanco and Carrasco-Letelier (2021) claims that agricultural eutrophication is not one of the main causes for cyanobacterial blooms in rivers and artificial reservoirs. By combining rivers of markedly different hydrological characteristics e.g., presence/absence and number of dams, river discharge and geological setting, the study speculates about the role of nutrients for modulating phytoplankton chlorophyll-a. Here, we identified serious flaws, from erratic and inaccurate data manipulation. The study did not define how erroneous original dataset values were treated, how the variables below the detection/quantification limit were numerically introduced, lack of mandatory variables for river studies such as flow and rainfall, arbitrary removal of pH > 7.5 values (which were not outliers), and finally how extreme values of other environmental variables were included. In addition, we identified conceptual and procedural mistakes such as biased construction/evaluation of model prediction capability. The study trained the model using pooled data from a short restricted lotic section of the (large) Uruguay River and from both lotic and reservoir domains of the Negro River, but then tested predictability within the (small) Cuareim River. Besides these methodological considerations, the article shows misinterpretations of the statistical correlation of cause and effect neglecting basic limnological knowledge of the ecology of harmful algal blooms (HABs) and international research on land use effects on freshwater quality. The argument that pH is a predictor variable for HABs neglects overwhelming basic paradigms of carbon fluxes and change in pH because of primary productivity. As a result, the article introduces the notion that HABs formation are not related to agricultural land use and water residence time and generate a great risk for the management of surface waterbodies. This reply also emphasizes the need for good practices of open data management, especially for public databases in view of external reproducibility.
Assuntos
Negro ou Afro-Americano , Rios , Monitoramento Ambiental , Eutrofização , Proliferação Nociva de Algas , Humanos , Fósforo/análise , Reprodutibilidade dos Testes , UruguaiRESUMO
El objetivo del presente trabajo fue la evaluación preclínica y el estudio de estabilidad de extractos a partir del follaje de Momordica charantia Lin. Se obtuvieron extractos acuoso e hidroalcohólico para los cuales se establecieron las especificaciones de calidad mediante la evaluación de tres lotes y se estudió su estabilidad por el método de vida de estante durante 12 meses. A los extractos se le evaluó el potencial genotóxico mediante ensayos de micronúcleos en médula ósea de ratón y aberraciones cromosómicas en linfocitos de sangre periférica. La actividad hipoglicemiante oral fue evaluada en animales con hiperglicemia temporal inducida por carga de glucosa. Como resultados se establecieron las especificaciones de calidad de los extractos acuoso e hidroalcohólico, los mismos mostraron estabilidad por 6 meses para el extracto acuoso y 12 meses para el extracto hidroalcohólico. No mostraron efecto genotóxico en los ensayos evaluados y mostraron efecto hipoglicemiante oral a la dosis de 450 mg/kg.
The objective of this investigation was the preclinical evaluation and the stability study of the Momordica charantia Linn hydroalcoholic and aqueous leaf extracts. The hydroalcoholic and aqueous extracts were obtained and the quality specifications were determined by evaluating three lots. The stability of the extracts was evaluated for 12 months. The genotoxic potential of the extracts was evaluated by mouse bone marrow micronucleus test and chromosome aberration test. The hypoglycemic effect was determined by oral glucose tolerance test. As results, the quality specifications were established and the aqueous extract was stable for 6 months and the hydroalcoholic extract for 12 months. A genotoxic effect was not observed in both extracts and the hypoglycemic effect was observed at the oral dose of 450 mg/kg of body weight.