Antibiotics and apochlorosis

Twenty-four out of 38 5-nitrofuran derivatives caused bleaching ofEuglena gracilis similar to that produced by streptomycin, erythromycin and other antibiotics. Derivatives with electron-donor substituents in thep-position of the benzene nucleus attached to position 2 of benzimidazole displayed the greatest bleaching activity. The addition of hydroxylamine to a growingEuglena gracilis culture together with a 5-nitrofuran interfered with the latter's bleaching effect. The mechanism of the effect of 5-nitrofurans on theEuglena gracilis chloroplast system is thus probably identical with the mechanism of the effect of streptomycin and erythromycin. A certain correlation was observed between the bleaching effect and the antibacterial activity of the various 5-nitrofurans tested.