Luminous Bacterial Auxanograms in Relation to Heavy Metals and Narcotics, Self-Photographed in Color

Abstract

Agar-plate auxanograms indicate that growth of Achromobacter fischeri and Photobacterium phosphoreum is strongly inhibited with pure metallic Cu, Co, Cd, or As; slightly with Zn, Pb, and Ni; but little or none with Mn, Mg, Bi, Al, or Au. Strong inhibitions were apparent with CoCl2, CuCl2, MnCl2; slight inhibitions with PbCl2 and MgCl2. Among organic compounds, growth was strongly inhibited by benzamide, p-aminobenzoic acid, novocaine, sulfapyridine, sulfanilamide, and Na-phenobarbital, slightly by sulfonmethane and Na-barbital. Glucose inhibited growth because of acid produced. A zone of stimulation between the normal and inhibited areas was generally evident through increased brightness of luminescence. The interpretation of the apparent stimulations is discussed in relation to certain factors and possible modes of action of the inhibitors. Color pictures of the cultures, taken by their own light, show the relative brightness of the different areas, as well as the quality of luminescence. The absolute brightness, measured with a modified Leeds and Northrup MacBeth Illuminometer, ranged between 0.002 and 0.040 millilamberts at room temp. for cultures incubated 1/2-4 days at optimum temp.