Amino acid-dependent transport of sugars by Fusobacterium nucleatum ATCC 10953

Abstract

Resting cells of Fusobacterium nucleatum 10953 (grown previously in a medium containing glucose) failed to accumulate glucose under aerobic or anaerobic conditions. However, the addition of glutamic acid, lysine, or histidine to anaerobic suspensions of cells caused the immediate and rapid accumulation of glucose. Except for the amino acid-dependent transport of galactose and fructose (the latter being transported at approximately one-third the rate of glucose), no other sugars tested were accumulated by the resting cells. Amino acid-dependent uptake of sugar(s) by F. nucleatum was abolished by exposure of cells to air, and under aerobic conditions the rates of fermentation of glutamic acid and lysine were <15% of the rates determined anaerobically. The energy necessary for active transport of the sugars (acetyl phosphate and ATP) is derived from the anaerobic fermentation of glutamic acid, lysine, or histidine. Competition studies revealed that glucose and galactose were mutual and exclusive inhibitors of transport, and it is suggested that the two sugars (Km = 14 ,uM) are translocated via a common carrier. The products of amino acid-dependent sugar transport were recovered from resting cells as ethanol-precipitable, high-molecular-weight polymers. Polymer formation by F. nucleatum, during growth in medium containing glucose or galactose, was confirmed by electron microscopy.

Gut microbiome development along the colorectal adenoma–carcinoma sequence

“…In some Fusobacterium species, however, transport of sugar depends on amino acid fermentation (Glu, Lys, His or Ser) 40,41 , suggesting that they only thrive in the presence of an ample supply of amino acids. Phenolic compounds are produced from fermentation of the aromatic amino acids phenylalanine and tyrosine 39 , which might increase DNA damage in the colon.…”

Pathways of glutamate catabolism among Fusobacterium species

“…Previous studies have so far revealed that carbohydrates, as energy sources, are poorly utilized and their Kermentatioii is limited to only a few species such as F. varium (Gharbia & Shah, 19886). Species were shown to assimilate 30-100% of the available glucose in the medium (Gharbia & Shah, 1988), but [14C]glucose incorporation experiments revealed that this is used for the biosynthesis of various cellular components (G harbia & Shah, 1989b) and storage glycopolymers (Robrish et al, 1987). The latter can, however, be metabolized in the absence of other fermentable substrates (Robrish & Thompson, 1988).…”

Metabolism of sucrose and its five isomers by Fusobacterium mortiferum

“…Fusobacteria are Gram-negative anaerobic rods that are usually described as weakly or asaccharolytic, and most species, including Fusobacterium nucleatum, use amino acids as fermentable energy sources (Robrish et al, 1987 ;Robrish & Thompson, 1990). The products of metabolism (acetic, butyric and propionic acids) may penetrate periodontal tissue, thereby contributing to the aetiology of gingivitis and periodontal disease.…”