Toxicity of dyes and related compounds to wood-destroying fungi.

In 1891 Ehrlich demonstrated the antimalarial activity of methylene blue and a few years later discovered that trypan red would kill trypanosomes. These disclosures helped lay the foundations of chemotherapy. Since that time many workers have studied the effects of dyes on microorganisms, among them Stearn and Stearn (1924). Dion and Lord (1944) and Aiquel and Herraro (1948) have shown that basic dyes are toxic to Fusarium culmorum and to two species of Aspergilli. Attempts have been made (by Mietzsch, 1936; Goldacre and Phillips, 1949; and Fischer, 1957) to relate the toxicity of these basic dyes to their structures. Michaelis and Granick (1945) and Michaelis (1947, 1949) attempted to explain the toxicity by showing that basic dyes react irreversibly with nucleic acids. Similar studies have been carried out by Neuberg and Roberts (1949), Steiner and Beers (1958), and di Marco and Boretti (1950). Basu and Whitaker (1953) found that acid anid basic dyes were inhibitory to the isolated cellulase of Mlyrothecium verrucaria. A United States patenit issued to Conn (1935) disclosed the use of crystal violet and malachite green for the preservation of cotton fish nets. In this laboratory we have studied the toxicity of dyes and certain related compounds to six species of wood-destroying fungi selected either because of their vigorous attack on wood or because of their economic importance to the wood-preserving industry. Initial screening was conducted on nutrient agar plates and this paper will deal with the results obtainied.