Portal de Periódicos da CAPES

Expression of Secondary Metabolism as Part of the Differentiation Processes During the Idiophase Development of Penicillium cyclopium Westling

1974; Elsevier BV; Volume: 166; Issue: 4 Linguagem: Inglês

10.1016/s0015-3796(17)30055-0

0015-3796

Lutz Nover, Martin Luckner,

Fungal and yeast genetics research

The development of emerged cultures of Penicillium cyclopium Westling on nutrient solution comprises three phases: the germination phase, a period of vigorous growth of the hyphae (trophophase), and a period of specialization (idiophase). The differentiation programs proceeding in the idiophase involve the formation of penicilli, the detachment and ripening of conidia, and the formation of enzymes catalyzing alkaloid biosynthesis. The beginning of the idiophase in emerged cultures is characterized by a decline of nucleic acid and protein synthesis to about 30–50% of the maximal value 48–72 hours after inoculation. In spite of pronounced differences with respect to the contents and rates of synthesis of proteins and nucleic acids under different nutrient conditions the time of triggering and the qualitative and quantitative relations between the individual features of idiophase development are barely influenced The most prominent morphogenetic feature at the beginning of the idiophase development is the specialization of the growth processes to the formation of penicilli and conidia. The penicilli contain a phenol oxidase, which presumably participates into the synthesis of the green pigment in the ripening conidia. The detachment of the conidia by unequal partition of the apical cells of the penicilli takes about two hours per conidium and involves as constitutive components the synthesis of saccharase and of the enzymes of cyncol biosynthesis. The ripening of the conidia is indicated by the formation of their pigment and by the synthesis of a peculiar enzyme of alkaloid metabolism, cyclopenase, which catalyzes the transformation of benzodiazepine to quinoline alkaloids and which is restricted to the conidia only.