<i>Fusobacterium</i>and<i>Leptotrichia</i>

Hofstad, Tor; Olsen, Ingar

doi:10.1002/9780470688618.taw0076

Cited by 1 publication

(1 citation statement)

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“…, 2010; Dewhirst et al. , 2010), Leptotrichia buccalis (Human Oral Taxon 563) occurs as a minor constituent of the total flora of plaque (Hofstad, 1992; Hofstad & Olsen, 2007; Eribe & Olsen, 2008). However, L. buccalis is highly saccharolytic (Kasai, 1965; Thompson, 2002) and, because it ferments a wide variety of monosaccharides and disaccharides to lactic acid, the bacterium has evident cariogenic potential (Brown & Gross, 1981; Hofstad, 1992).…”

Section: Introductionmentioning

confidence: 99%

Metabolism of sugars by genetically diverse species of oral Leptotrichia

Thompson

Pikis

2011

Molecular Oral Microbiology

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SUMMARY Leptotrichia buccalis ATCC 14201 is a Gram-negative, anaerobic rod-shaped bacterium resident in oral biofilm at the tooth surface. The sequenced genome of this organism reveals three contiguous genes at loci: Lebu_1525,1526 and 1527. The translation products of these genes exhibit significant homology with phospho-α-glucosidase (Pagl), a regulatory protein (GntR) and a phosphoenol pyruvate-dependent sugar transport protein (EIICB), respectively. In non-oral bacterial species, these genes comprise the sim operon that facilitates sucrose isomer metabolism. Growth studies showed that L. buccalis fermented a wide variety of carbohydrates, including four of the five isomers of sucrose. Growth on the isomeric disaccharides elicited expression of a 50kDa polypeptide comparable in size to that encoded by Lebu_1525. The latter gene was cloned, and the expressed protein was purified to homogeneity from Escherichia coli TOP 10 cells. In the presence of two cofactors, NAD+ and Mn2+ ion, the enzyme readily hydrolyzed p-nitrophenyl-α-glucopyranoside 6-phosphate (pNPαG6P), a chromogenic analog of the phosphorylated isomers of sucrose. By comparative sequence alignment, immuno-reactivity and signature motifs, the enzyme can be assigned to the phospho-α-glucosidase (Pagl) clade of Family 4 of the glycosyl hydrolase super family. We suggest that the products of Lebu_1527 and 1525, catalyze the phosphorylative translocation and hydrolysis of sucrose isomers in L. buccalis, respectively. Four genetically diverse, but 16S rDNA related species of Leptotrichia have recently been described: L. goodfellowii, L. hofstadii, L. shahii and L. wadei. The phenotypic traits of these new species, with respect to carbohydrate utilization, have also been determined.

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