Role of the Pentose Phosphate Pathway in Pasteurella multocida

Abstract

IT is acknowledged that in a large number of bacteria the main path for carbohydrate oxidation is the pentose phosphate cycle or other metabolic sequences not involving the Embden–Meyerhof pathway¹. In the genus Pasteurella, work on P. pestis has shown that growing cells oxidize glucose through the pentose phosphate pathway², but resting cells oxidize glucose through the combined action of glycolysis and the citric acid cycle³. In contrast with this metabolic duality, in P. multocida the pentose phosphate cycle is the main path for carbohydrate oxidation, both in growing and resting cells, and in regard to the citric acid cycle its principal role seems to be to supply carbon skeletons for the synthesis of amino-acids. These conclusions are borne out by experiments carried out with P. multocida (strain Beaufort No. 28 from the Institut Pasteur cultured aerobically for 4 hr. (growing cells) or 24 hr. (resting cells)) at 37° and pH. 7.2 in a medium made of meat extract, 5 gm. ; yeast extract (Difco), 1 gm. ; peptone, 30 gm.; sodium chloride, 5 gm.; glucose, 20 gm. ; agar, 25 gm. and water up to 1 litre. Our observations can be summarized as follows.