Wang, Ping Tu2022-05-092022-05-091975http://hdl.handle.net/10919/109964The energy metabolism of three strains of Camplyobacter fetus (i.e., C. fetus ss. fetus 482, C. fetus ss. intestinalis PB1, and C. fetus ss. jejuni H840) was investigated. A biphasic culture technique was employed to grow the culture, and from which crude cellular extracts were prepared. The growth of the organisms was extremely slow when a basal medium (BM) was used. At a level of 0.5% carbon source in BM, the growth of 482 was stimulated by glucose, lactate and acetate; citrate showed no effect. The growth of PB1 was stimulated by lactate and acetate; glucose had no effect and citrate inhibited the growth slightly. The growth of H840 was stimulated by glucose and citrate; acetate had no effect. All enzyme assays were performed at 25 C in a Perkin-Elmer model 124 double beam spectrophotometer. The reaction mixture was 3 ml which contained the appropriate substrate, cofactors and properly diluted crude cellular extract. The specific activity of an enzyme was defined as µmoles of substrate transformed per minute per mg of protein. When the strains of C. fetus were grown in an enriched medium, the citric acid cycle was actively operating except that α-ketoglutarate dehydrogenase was undetectable in 482 and PB1, and very weak in H840. The interruption in the cycle was supported by the reaction of isocitrate lyase which is a key enzyme of the glyoxylate bypass, and was found in the three strains. Malate synthase was not detectable in either of them, but can be induced by growing the organisms in BM + 0.5% glucose or 0.5% acetate. No pyruvate dehydrogenase was found in either strain. Pyruvate was carboxylated by pyruvate carboxylase in H840 and by malic enzyme in 482 and PB1. All of them contained the activities of aspartase and glutamate dehydrogenase. Glucose was not assimilated by C. fetus. α-methyl-D-glucoside was not absorbed by C. fetus 482 which was grown in the BM with or without glucose. It is believed that 482 does not possess a glucose permease system or that such a system can not be induced by growing the organism in a medium containing glucose. Furthermore, free glucose was not phosphorylated in 482 by glucokinase or acetylphosphate: hexose phosphotransferase. The activities of 6 key enzymes of the Embden-Meyerhof pathway were all found in 482; therefore, the pathway is actively operating and presumably served as a synthetic scheme for the formation of hexose phosphate in the organism. The oxidative portion of both the hexose monophosphate pathway and phosphoketolase pathway, and the entire Entner-Dudoroff pathway were not found in 482. But the non-oxidative portions of the former pathways were present in 482 and is believed to compose the major pathway of pentose-5-phosphate metabolism in this organism. There were activities of lactate dehydrogenase, reduced NAD and NADP dehydrogenases, and phosphotransacetylase found in 482. No ribokinase and gluconokinase were detectable in this organism.vii, 123 leavesapplication/pdfenIn CopyrightLD5655.V856 1975.W35Dissertation