Ah. Rogers et al., THE BEHAVIOR OF FUSOBACTERIUM-NUCLEATUM CHEMOSTAT-GROWN IN GLUCOSE-BASED AND AMINO ACID-BASED CHEMICALLY-DEFINED MEDIA, Anaerobe, 4(2), 1998, pp. 111-116
Fusobacterium nucleatum is a Gram-negative anaerobe, found in a number
of different areas of human and animal bodies as part of the resident
microbiota. However, it also appears to be involved in polymicrobial
infections in such sites. It occurs in the oral cavity where it is a p
rominent member of various bacterial consortia associated with periodo
ntal diseases. Like most fusobacteria, it derives energy via the ferme
ntation of amino acids which it can obtain through the dissimilation o
f small peptides. However, the role of simple carbohydrates, such as g
lucose, in its growth and metabolism are not well understood. Accordin
gly, the aim of the present study was to study the behaviour of F. nuc
leatum grown anaerobically in continuous culture in two different chem
ically-defined media (CDM); one containing only amino acids as the ene
rgy source, the other containing glucose as the predominant energy pro
vider. At various dilution rates the culture were assayed for dry weig
ht, intracellular polyglucose (IP) content, residual amino acids and g
lucose and acidic metabolic end-products. Ln the carbohydrate-free CDM
the acidic end-products were a constant acetate : butyrate : formate
of 1.5:1:0.4. The values of Y-amino acids(max), maximum yield of bacte
ria per mel of amino acids consumed, for two strains were estimated to
be 15.2 and 18.6 g dry wt/mol, respectively. The m(amino acids), main
tenance energy requirement for growth on amino acids, for the two stra
ins was 0.81 and 0.94mmol/g dry wt/h, respectively. Growth of one stra
in in the glucose-based CDM gave an estimated Y(glucose)max of 67.2 an
d an m(glucose) of 0.38; the acidic end-products were a fairly constan
t acetate : butyrate : formate : lactate of 0.7:1:0.3:2.5. Only at low
growth rates, and then only in small amount, was LP produced in this
medium. Overall, it was concluded that the occurrence of F. nucleatum
in widely-differing oral niches may be explained, at least in part, by
its metabolic versatility. (C) 1998 Academic Press.