Thioguanine-dependent Light Sensitivity of Perithecial Initiation in Sordaria fimicola

Abstract

S U M M A R YPerithecial initiation is strongly inhibited by visible light in less than 18-hr-old hyphae of Sordariajimicola which are grown in the presence of I p~-6-thioguanine. It is known that 6-thioguanine is destroyed when exposed to light in vitro with oxygen and a sensitizing dye like methylene blue is present. The most effective wavelength region for perithecial inhibition is the blue region, indicating that possibly flavins are the photosensitizing compounds in this case. The synthesis of carotenoid and melanin pigments is also affected by blue light in this organism. Another, transient, inhibitory effect on perithecial production is found when light-grown cultures are transferred to darkness. As a consequence of the two light effects, mycelia exposed to alternating light and dark periods in growth tubes develop welldefined zones of perithecia. A simple state-input model is presented in the Appendix to demonstrate how such zonation patterns can be generated on the basis of the light effects and a few other assumptions.

Perithecial Formation in Gelasinospora Reticulispora. I. Effects of Light at Two Different Growth States

“…In Hypomyces solani f. cucurbitue (CURTIS, 1964) and Diaporthe phuseolorum var. batatatis (TIMNICK,et al,195 1) a photoinhibitory effect was observed but the state of hyphal tip growth was not stated, and in Sorduriu firnicolu (SURAPIPITH and LINDENMAYER, 1969) this effect was observed while the tip was growing, although responses to light after the tip of hyphae reached the other end of the growth tube were not mentioned.…”

“…butututis (TIMNICK,et al,195 1) It is common for sporulation to commence when the mycelium of a colony growing in artificial culture reaches the edge of the petri dish (HAWKER, 1966). In Pleuruge setosu (CALLAGHAN, 1962) and Sorduriufimicolu (SURAPIPITH and LINDENMAYER, 1969), the effect of light on perithecial formation was investigated while the hyphal tip was growing. However, no studies have been reported on the interaction between the effect of light on perithecial formation and the state of hyphal tip growth.…”

Extending the Programming Language XL to Combine Graph Structures with Ordinary Differential Equations

“…In some cases it might be desirable to have multiple sets of rules. An example can be TOL-system found in [SL69], where growth behaviour in light is different from the one in darkness. An extension to OL-systems proposed by Rozenberg are table L-systems, also TOL-systems [Roz73].…”