RESUMEN
Four new leucine-derived cytochalasans, possessing a 5,6,5,8-ring (1) and a 5,6,11-ring core (2-4), were isolated from a cultivated endophytic fungus Xylaria sp. strain WH2D4 (Xylariaceae). This fungus was isolated from leaves of the neotropical tree species Palicourea elata (Sw.) Borhidi (Rubiaceae) collected in Costa Rica. The chemical structures were determined by employing IR, MS as well as 1D- and 2D-NMR experiments. The stereochemistry at C-15 of compound 4 was determined by quantum calculations. The isolated compounds did not affect germination and growth of Trichoderma reesei and the opportunistic human fungal pathogen T. longibrachiatum.
Asunto(s)
Rubiaceae , Xylariales , Humanos , Costa Rica , Rubiaceae/química , Xylariales/química , Espectroscopía de Resonancia Magnética , Citocalasinas/químicaRESUMEN
The topic of 'fungal stress' is central to many important disciplines, including medical mycology, chronobiology, plant and insect pathology, industrial microbiology, material sciences, and astrobiology. The International Symposium on Fungal Stress (ISFUS) brought together researchers, who study fungal stress in a variety of fields. The second ISFUS was held in May 8-11 2017 in Goiania, Goiás, Brazil and hosted by the Instituto de Patologia Tropical e Saúde Pública at the Universidade Federal de Goiás. It was supported by grants from CAPES and FAPEG. Twenty-seven speakers from 15 countries presented their research related to fungal stress biology. The Symposium was divided into seven topics: 1. Fungal biology in extreme environments; 2. Stress mechanisms and responses in fungi: molecular biology, biochemistry, biophysics, and cellular biology; 3. Fungal photobiology in the context of stress; 4. Role of stress in fungal pathogenesis; 5. Fungal stress and bioremediation; 6. Fungal stress in agriculture and forestry; and 7. Fungal stress in industrial applications. This article provides an overview of the science presented and discussed at ISFUS-2017.
Asunto(s)
Hongos/fisiología , Hongos/patogenicidad , Estrés Fisiológico , Brasil , Microbiología Ambiental , Microbiología Industrial , MicologíaRESUMEN
In Trichoderma reesei light stimulates transcription of cellulase genes and this regulation has been found to occur, at least in part, through the protein ENVOY. Here we analyzed the role of the BLR photoreceptor complex (BLR1/BLR2) in photoconidiation and the regulation of gene expression. Both responses were dependent on both BLR proteins. Analyses of Deltablr1, Deltablr2 and Deltaenv1 mutants showed that the BLR proteins regulate growth under illumination. Analysis of env1 mutant strains indicated that ENVOY allows the fungus to tolerate continuous exposure to light, damped the capacity of Trichoderma to perceive changes in light intensity, and suggested that it participates in a negative regulatory feedback. Its activity as repressor establishes a period of insensitivity to a second light treatment. Interestingly, the stimulation of cellulase gene expression by light was also modulated by both blr1 and blr2, indicating a key role of the BLR proteins in this pathway.