RESUMO
The effect of a beta-1,3-glucanase (Glucanex) on cultures of Botrytis cinerea was examined. The enzyme released reducing sugars from the mycelium and from the glucan secreted into the culture medium. The morphology of the mycelium was changed in the presence of Glucanex. The measured activity of guaiacol peroxidase, laccase, and catalase was increased when the mycelium was treated with Glucanex. Culture of the mycelium in the presence of Glucanex resulted in an increase in catalase activity. We suggest that the glucan plays a role in protecting the fungus from host response and may assist in the initial stages of host infection.
Assuntos
Botrytis/enzimologia , Glucanos/metabolismo , beta-Glucosidase/metabolismo , Botrytis/crescimento & desenvolvimento , Botrytis/patogenicidade , Meios de Cultura , Fabaceae/microbiologia , Glucana 1,3-beta-Glucosidase , Glucose/metabolismo , Doenças das Plantas/microbiologia , Plantas MedicinaisRESUMO
The amounts of intra- and extracellular guaiacol peroxidase, ascorbic peroxidase, glutathione peroxidase, superoxide dismutase, laccase, and catalase present in Botrytis cinerea, cultured in three different media: Kovac synthetic medium, Sabouraud fluid medium, and a medium containing malt extract, were determined. The activity of two enzymes, ascorbic peroxidase and glutathione peroxidase, has not been previously described in B. cinerea. The detected amount of the enzymes showed considerable variability in the three different culture media. The presence of an array of enzymes capable of metabolizing hydrogen peroxide, whose levels are determined by the conditions under which the fungus grows, shows that B. cinerea is well equipped to contend with the occurrence of host-produced active oxygen species.
Assuntos
Botrytis/enzimologia , Peróxido de Hidrogênio/metabolismo , Peroxidases/metabolismo , Botrytis/crescimento & desenvolvimento , Meios de Cultura/química , Lacase , Oxirredutases/metabolismo , Peroxidases/classificação , Superóxido Dismutase/metabolismoRESUMO
A mixture of gases roughly simulating the primitive terrestrial atmosphere has been subjected to shock heating followed by a rapid thermal quench. Under strictly homogeneous conditions there is a very high efficiency of 5 x 10(10) molecules per erg of shock-injected energy for production of alpha-amino acids. Calculations suggest that rapid quenching bypasses the usual thermochemical barrier. The product of energy flux and efficiency implies the unexpected conclusion that shocks occurring on atmospheric entry of cometary meteors and micrometeorites and from thunder may have been the principal energy sources for pre-biological organic synthesis on the primitive earth.
