The Inhibition of Phytomonas Malvaceara in Culture Media Containing Sugars

Utilization of Glucose by Astasia longa*

“…The 0 2 consumption by parent-strain cells was the same in both cases, whereas strain 460-17 cells consumed more O2 in the presence of glucose. Autoclaving glucose-containing media under certain conditions change the glucose molecule ( 13,17,18,19,22). That strain 460-17 was utilizing some compound derived from glucose rather than glucose itself was ruled out: growth of strain 460-17 was comparable in a medium that contained filter-sterilized glucose and in a medium in which glucose was present at autoclaving.…”

Heat Sterilised Reducing Sugars and Their Effects on the Thermal Resistance of Bacteria

“…It would appear, therefore, that along with caramelisation, some other chemical compound is produced, which in the pure state must be highly toxic to bacteria. Lewis (1930) discussed the literature concerning the transformations which occur in sugars under the influence of heat and various compounds such as phosphates and caustic alkalies, and concluded that the material causing growth inhibition in his experiments was an aldehyde: This aldehyde combined with the nitrogen source in the medium and rendered it non-assimilable. Ambler and Byall (1935) have reported extensive data on the influence of non-sugars on the caramelisation and inversion of sucrose, drawing attention to the deep-seated and complex isomerisations and degradations involved.…”

“…In addition to the toxicity of heat-sterilised glucose nutrient broth demonstrated in the thermal resistance tests (table 1), it has been found that such a medium is also capable of retarding the growth of E. coli (table 8). Lewis (1930) found that the production of inhibitory media was affected by the phosphate content of the medium, at least 0.2 per cent K2HPO4 being required for inhibition to occur. He also found that a glucose medium which was inhibitory for some species did not inhibit the growth of E. coli.…”

“…Heat treatment of the solutions was completely avoided. Lewis (1930) observed that solutions of glucose in distilled water autoclaved at 1220C. did not cause growth inhibition when incorporated in a nutrient medium.…”

“…The stimulant was not caramel but a substance produced parallel with caramel. Previously, Lewis (1930) reported that growth of some types of bacteria was completely inhibited in media containing either glucose, maltose, lactose, galactose or levulose which together with phosphate and a source of nitrogen had been sterilized at 1220C. for 15 minutes.…”