Changes in growth and polyglucose synthesis in response to fructose metabolism byFusobacterium nucleatumgrown in continuous culture

Abstract

Fusobacterium nucleatum, grown in a chemically defined medium at micro(rel) = 0.5, produced greater cell yields and undetectable levels of intracellular polyglucose (IP) when fructose was substituted for glucose. The utilisation and metabolism of fructose by growing cells was studied and the effect of the energy-yielding amino acids, glutamate, serine, histidine and lysine on cell yield, IP synthesis and acidic end-products was investigated. When F. nucleatum was grown on elevated amino acid levels, IP was synthesised from fructose and amino acids were metabolised to lactate, acetate, butyrate and formate. Under these conditions, IP synthesis was associated with the cells being replete with amino acid-derived energy; an observation supported by the absence of IP when the levels of (energy yielding) amino acids were reduced. Compared with fructose, glucose was less efficiently removed from the growth medium and produced less biomass and markedly lower levels of IP during energy-limited growth.

The proteomic profile of Fusobacterium nucleatum is regulated by growth pH

“…It has been reported that in resting (non-growing) cells the fermentation of glutamate and lysine occurs preferentially and the energy produced is used for the active transport of glucose, which is stored as intracellular polysaccharide (IP) (Robrish et al, 1987;Robrish & Thompson, 1990). Our earlier studies on F. nucleatum growing in continuous culture showed that during glutamate fermentation, growth at pH 7.8 produced maximum levels of IP (Zilm et al, 2003). It has been reported that high levels of glutamate are present in the inflamed periodontium (Singer & Kleinberg, 1983), and fructose diphosphate has been previously described as a branch point in determining the fate of glucose into energy (ATP) or synthesis of IP (Robrish & Thompson, 1990).…”

A proteomic investigation of Fusobacterium nucleatum alkaline-induced biofilms

“…However, a three-fold increase in glucose utilisation and IP was observed (Table 2, Figure 3). It is possible that the observed increase in glucose storage may play an important role in the organism’s survival during periods of nutrient limitation when exposed to pH 8.2 [43,49,50]. Although the expression of glycolytic enzymes was not significantly altered, an increase in lactate dehydrogenase (LDH) (EC 1.1.2.8) and a three-fold increase in lactate production was observed, indicating a metabolic shift at pH 8.2 towards ATP generation via anaerobic glycolysis (Embden-Meyerhof-Parnas pathway) (Tables 1 and 2, Figure 3).…”

Effects of Probiotic Supplementation on Exercise and the Underlying Mechanisms

“…Fusobacterium can produce secondary and tertiary bile acids, which affect systemic glucose metabolism and energy expenditure, thereby influencing skeletal muscle metabolism [27].…”