Pre-illumination of rice blast conidia induces tolerance to subsequent oxidative stress

Many environmental factors, alone or combined, affect organisms by changing a pro-/antioxidant balance. Here we tested rice blast fungus (Magnaporthe oryzae) for possible cross-adaptations caused by relatively intense light and protecting from artificially formed reactive oxygen species (ROS) and ROS-dependent fungitoxic response of the host plant. Spore germination was found to be suppressed under 4-hand, to larger extent, 5-hillumination. The effect was diminished by antioxidants and, therefore, suggests involvement of ROS. One-hour of light did not affect spore germination, but stimulated their chemically assayed superoxide production. The illuminated spores were more tolerant (than non-illuminated ones) to artificially generated H2O2, O2 -, or OH or to toxic diffusate of rice leaf. They also caused more severe disease symptoms if applied to leaves of the susceptible rice cultivar at low concentration. Spore diffusates decomposed hydrogen peroxide. They detoxified exogenous H2O2 and superoxide radical as well as leaf diffusates. Spore illumination increased some of these protective effects. It is suggested that short-term light led to mild oxidative stress, which induced spore antioxidant capacity, enhancing spore tolerance to subsequent stronger oxidative stress and its aggressiveness in planta. Such tolerance depends partly on the antidotal action of spore extracellular compounds, which may also be light-stimulated. Therefore, a certain ROS-related environmental factor may adapt a fungus to other factors and so modulate its pathogenic properties. © 2014 The British Mycological Society

Pre-illumination of rice blast conidia induces tolerance to subsequent oxidative stress

Many environmental factors, alone or combined, affect organisms by changing a pro-/antioxidant balance. Here we tested rice blast fungus (Magnaporthe oryzae) for possible cross-adaptations caused by relatively intense light and protecting from artificially formed reactive oxygen species (ROS) and ROS-dependent fungitoxic response of the host plant. Spore germination was found to be suppressed under 4-hand, to larger extent, 5-hillumination. The effect was diminished by antioxidants and, therefore, suggests involvement of ROS. One-hour of light did not affect spore germination, but stimulated their chemically assayed superoxide production. The illuminated spores were more tolerant (than non-illuminated ones) to artificially generated H2O2, O2 -, or OH or to toxic diffusate of rice leaf. They also caused more severe disease symptoms if applied to leaves of the susceptible rice cultivar at low concentration. Spore diffusates decomposed hydrogen peroxide. They detoxified exogenous H2O2 and superoxide radical as well as leaf diffusates. Spore illumination increased some of these protective effects. It is suggested that short-term light led to mild oxidative stress, which induced spore antioxidant capacity, enhancing spore tolerance to subsequent stronger oxidative stress and its aggressiveness in planta. Such tolerance depends partly on the antidotal action of spore extracellular compounds, which may also be light-stimulated. Therefore, a certain ROS-related environmental factor may adapt a fungus to other factors and so modulate its pathogenic properties. © 2014 The British Mycological Society

Anti-Tumor Efficacy of Photodynamic Therapy of Solid Tumors in Laboratory Animals with Guanidine and Biguanidine Derivatives of Chlorine e6

We evaluated antitumor efficacy of photodynamic therapy of murine Ehrlich carcinoma and rat sarcoma M-1 with new photosensitizers 131-N-(4-aminobutyl)amydo chlorine e6 (1), 132-(5-guanidylbutanamido)-chlorine e6 (2), and 132-(5-biguanidylbutanamido)-chlorine e6 (3). The inhibiting effect of the photodynamic therapy was evaluated by the following parameters: tumor growth inhibition, complete regression of the tumors, and absolute growth rate of the tumor nodes in animals with the continued neoplasia growth. The criterion of cure was the absence of tumors up to 90 days after the therapy. It is shown that the studied photosensitizers have high antitumor activity in the photodynamic therapy of the Ehrlich carcinoma and sarcoma M-1