Presence of glyphosate can harm the germination of bean seeds treated with biostimulant / Presença de glifosato pode prejudicar a germinação de sementes de feijoeiro tratadas com bioestimulante

It is possible to cultivate common beans for a third harvest in one agricultural year due to varietal characteristics. For calendar adequacy, performing desiccation and planting often occur almost simultaneously. Germination performance of many plant species can improve with biostimulant use on seeds, however the interaction with herbicide residual molecules is unknown. The hypothesis is that seeds treated with a biostimulant in soil with glyphosate residues can eliminate the advantage of the biostimulant or increase the damage caused by the herbicide. The aim of this study was to evaluate the effect of different glyphosate reduce doses and the interaction with biostimulant on bean seed germination and vigor. The experiment was conducted using a completely randomized 2 x 5 factorial block designing factorial 2 x 5, corresponding to the presence and absence of biostimulant and five different doses of glyphosate reduce rates, with four repetitions. The conducted evaluations were first count germination, germination test, accelerated aging, cold test, root and shoot length, root and shoot dry matter and electrical conductivity. It can be concluded that the biostimulant treatment on bean seeds increased germination, seed vigor and early seedling growth, but glyphosate presence reduced those advantages, increasing electrical conductivity. However, the herbicide presence provided higher germination on the accelerated aging test.

Devido às características de variedades de feijoeiro comum, é possível seu cultivo como terceira safra em um ano agrícola. Para adequação ao calendário, a prática de dessecação e plantio muitas vezes ocorrem quase simultaneamente. A utilização de bioestimulantes em sementes pode aumentar o desempenho germinativo de diversas espécies de plantas, no entanto a sua interação com moléculas residuais de herbicidas é desconhecido. A hipótese é que o uso de sementes tratadas com bioestimulante em solos com resíduos de glifosato pode eliminar as vantagens do primeiro ou amentar os danos causados pelo herbicida. O objetivo do trabalho foi avaliar o efeito de subdoses de glifosato e bioestimulante em sementes de feijoeiro. O experimento foi realizado em blocos inteiramente casualizados em fatorial 2x5, correspondendo a ausência e presença de bioestimulante e cinco subdoses de glifosato, com quatro repetições. As avaliações foram primeira contagem de germinação, teste de germinação, envelhecimento acelerado, teste de frio, comprimento de parte aérea e de raiz, massa seca de parte aérea e de raiz e condutividade elétrica. Conclui-se que o tratamento de sementes de feijoeiro com bioestimulante eleva a germinação, o vigor de sementes e o crescimento inicial de plântulas, porém a presença de glifosato elimina essas vantagens, revelando maior condutividade elétrica. No entanto, a presença do herbicida proporciona maior germinação no teste de envelhecimento acelerado.

Mitochondrial Toxins and Healthy Lifestyle Meet at the Crossroad of Hormesis

Mitochondrial function is crucial for the maintenance of cellular homeostasis under physiological and stress conditions. Thus, chronic exposure to environmental chemicals that affect mitochondrial function can have harmful effects on humans. We argue that the concept of hormesis should be revisited to explain the non-linear responses to mitochondrial toxins at a low-dose range and develop practical methods to protect humans from the negative effects of mitochondrial toxins. Of the most concern to humans are lipophilic chemical mixtures and heavy metals, owing to their physical properties. Even though these chemicals tend to demonstrate no safe level in humans, a non-linear dose-response has been also observed. Stress response activation, i.e., hormesis, can explain this non-linearity. Recently, hormesis has reemerged as a unifying concept because diverse stressors can induce similar stress responses. Besides potentially harmful environmental chemicals, healthy lifestyle interventions such as exercise, calorie restriction (especially glucose), cognitive stimulation, and phytochemical intake also activate stress responses. This conceptual link can lead to the development of practical methods that counterbalance the harm of mitochondrial toxins. Unlike chemical hormesis with its safety issues, the activation of stress responses via lifestyle modification can be safely used to combat the negative effects of mitochondrial toxins.

Aspirina en dosis ultrabajas y hormesis / Aspirin in ultra-low doses and hormesis

La relación entre hormesis y Homeopatía resulta hoy en día controvertida. Por un lado, sus primeros fundamentos fueron enunciados con el objeto de explicar los efectos de la Homeopatía. Por otro lado, la mayoría de los trabajos realizados que muestran efectos horméticos fueron realizados a concentraciones mucho mayores que las utilizadas en Homeopatía. El presente trabajo muestra varios puntos de contacto entre la Homeopatía y el concepto de hormesis, y muestra la relación que existe entre los trabajos realizados sobre los efectos de la aspirina 15CH y los distintos tipos de hormesis.

Low-dose Gamma-irradiation Effect on Early Stage Development and Lifespan in Various Strains of Drosophila melanogaster / 대한산업의학회지

OBJECTIVES: Although ionizing radiation is recognized as being harmful to humans, debate continues regarding the effects of low doses of ionizing radiation. Some studies have reported that low doses of ionizing radiation have a bio-positive effect, namely hormesis, and many researchers have attempted to find concrete and scientific evidence to prove this. To determine whether the discrepancy in effects of low doses of ionizing radiation arises from genetic differences, a study with a multicellular organism system such as fruit flies is needed. METHODS: After irradiation at a low-dose rate of gamma radiation with chronic (0.2 Gy) and acute (0.2, 0.75 and 4 Gy), the pupa rate, eclosion rate and life span were examined with various wild type strains of Drosophila melanogaster such as W1118, Oregon-R, and Canton-S. RESULTS: The life span of Oregon-R exposed to both acute and chronic, low-dose radiation (0.2 Gy) was increased. Although there was some difference in the longevity between the acute and chronic radiation rate, no other differences were found. In Canton-S, only acute dose (0.75 Gy) increased the life span, but it did not in W1118. CONCLUSIONS: Although there were some differences between wild type fruit fly strains in longevity, the low doses of ionizing radiation extended the life span of D. melanogaster. Further studies need to be carried out to explain the difference according to dose and dose rate of radiation in the tested strains.

Low-dose Radiation-induced Hormetic Effect in the Rat Ovarian Follicle / 체질인류학회지

Hormesis is the generally-favorable biological responses to low exposures to toxins and other stressors. Radiation hormesis is the theory that ionizing radiation is benign at low levels of exposure, and that doses at the level of natural background radiation can be beneficial. The purpose of this study is to reveal the hormetic effect of low-dose radiation of ionizing radiation on the ovarian follicles of 4-week old female mice. Mice were grouped into control group, 2 cGy irradiated group, 2 cGy and 2 Gy irradiated group (2 cGY pre-exposure group), and 2 Gy irradited group. Mice were sacrificed by cervical dislocation 24 hours after irradiation, removed ovaries, fixed in neutral formaldehyde solution for 24 hours, embedded with paraffin, stained with hematoxylin and eosin and TUNEL immunohistochemically, and observed light microscopically the atretic follicles and normal follicles in various follicular developmental stages. In this experiment, the ratrio of atretic follicles to entire follicles in an ovary increased significantly in 2 Gyirradiated group compared with 2 cGY pre-exposure group, and the ratio of normal follicles to the entire follicles in an ovary in all the developmental stages were increased significantly in the 2 cGY pre-exposure group compared with 2 Gy-irradiated group. These results mean that low-dose radiation pre-exposure can induce the hormetic effect in the developing ovarian follicle.