Reference

Biological effects of dyes on bacteria

Biological effects of dyes on bacteria. VI. Mutation induction by acridine orange and methylene blue in the dark with special reference to Escherichia coli WP6 (polA1). Webb, Robert B.; Hass, Bruce S. (Div. Biol. Med. Res., Argonne Natl. Lab., Argonne, IL 60439, USA). Mutat. Res., 137(1), 1-6 (English) 1984. CODEN: MUREAV. ISSN: 0027-5107. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) Acridine orange (AO)(I) [65-61-2] and methylene blue (MB) [28983-56-4] in the dark were weak to moderate mutagens (induction of resistance to T5 phage) in repair-deficient strains of E. coli B/r. However, strain WP2 (wild-type) was not mutated by AO in the dark. The presence of 2 mM AO reduced by 41% the spontaneous mutation rate in strain WP2, from 4.1 to 2.4 mutants/108 cells/generation. In the polymerase I-deficient strain WP6 (polA1), 2 mM AO increased the mutation rate in the dark 14-fold. Thus, both spontaneous and AO-induced mutagenesis in the absence of light may occur at the site of semiconservative DNA replication. If the intercalation mechanism for the effects in the absence of light is valid, the wild-type strain may be resistant to frameshift mutagenesis induced by intercalated compds., while the polymerase I-deficient strain may be highly susceptible to the presence of an intercalated dye such as AO at the DNA-replication fork. MB and AO likely act through different mechanisms since MB was only a moderate mutagen in strain WP6 and the other repair-deficient strains tested.

Induction of metachromasia by cationic metal coordinates

Induction of metachromasia by cationic metal coordinates. Srivastava, V. K.; Tripathi, Ajai M.; Misra, Braj B.; Singh, Chanan (Dep. Chem., Univ. Gorakhpur, Gorakhpur, India). Transition Met. Chem. (Weinheim, Ger.), 3(1), 38-42 (English) 1978. CODEN: TMCHDN. ISSN: 0340-4285. DOCUMENT TYPE: Journal CA Section: 40 (Dyes, Fluorescent Whitening Agents, and Photosensitizers) Section cross-reference(s): 63, 73 Cationic metal complexes of Co, Cr, and Cu induce true metachromasia in methyl blue (I) [28983-56-4] and produce a stronger metachromatic reaction than do known chromotropes. The spectral shifts and metachromatic effects increase with increasing complex to I ratio. The metachromatic reactions are suppressed by urea [57-13-6], versene [60-00-4], and propanol [71-23-8], and by buffer solns. Polyornithine (II) [25104-12-5], polylysine (III) [25104-18-1], neomycin [1404-04-2], dextramycin [134-90-7], and kanamycin [8063-07-8] behaved as very strong chromotropes. II and III produced metachromasia which was highly resistant to the actions of versene, urea, and pH. Among simple cations, Cu, Ag, Co, Cr, and Pb were nonmetachromatic and La, Th, Nd, and Sn produced insignificant metachromsia.