Production of Levan and Dextran in Plaque In Vivo

Gold, William; Preston, F. Barrie; Lache, Marvin; Blechman, Harry

doi:10.1177/00220345740530024401

Cited by 19 publications

(21 citation statements)

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“…Maximal synthesis of the enzyme(s) was observed at low growth rates, while little activity was produced by cultures grown at high dilution rates in continuous culture (23,47,48). Regulation of fructanase in this manner could have the net effect of allowing fructan reserves to accumulate in plaque during periods of dietary sucrose intake, as has been observed (16,21). Then, at a later time, when exogenous sources of carbohydrate were exhausted, induction of synthesis of fructan hydrolase activity would permit degradation of these polymers in plaque.…”

mentioning

confidence: 77%

“…The actual synthesis and accumulation of fructans by human dental plaque samples in vitro (22) as well as the accumulation of fructans in plaque in vivo in studies with human volunteers fed a diet rich in sucrose have been demonstrated (16). Following a sucrose intake, fructans were shown to accumulate rapidly and the level of keto sugar slowly decreased with time.…”

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confidence: 98%

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Expression, purification, and characterization of an exo-beta-D-fructosidase of Streptococcus mutans

et al. 1987

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A genetic library of Streptococcus mutans GS-5, constructed in an Escherichia coli plasmid vector, was screened for cells which could utilize sucrose as the sole carbon and energy source. The recombinant plasmid pFRU1, containing a 4.2-kilobase pair insert of S. mutans DNA, was shown to confer this phenotype. Further characterization of the gene product encoded by pFRUl revealed that the enzyme was a P-D-fructosidase with the highest specificity for the j(2-*6)-linked fructan polymer levan. The enzyme could also hydrolyze inulin [13(2-+1)-linked fructan], sucrose, and raffinose with 34, 21, and 12%, respectively, of the activity observed for levan. The gene (designated fruA) appeared to be expressed under its own control in E. coli, as judged by the lack of influence on gene product activity of induction or repression of the ,I-galactosidase promoter adjacent to the insertion site on the cloning vector. The protein was purified to homogeneity, as judged by silver staining of purified protein in denaturing and reducing conditions in polyacrylamide gels, from sonic lysate of E. coli, as well as from culture supernatants of S. mutans GS-5 grown in a chemostat at low dilution rate with fructose as the sole carbohydrate source. Both purified proteins had an apparent molecular mass of 140,000 daltons in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, were immunologically related and comigrated in sodium dodecyl sulfate-polyacrylamide gel electrophoresis as determined by Western blotting with antisera raised against the cloned gene product, and were identical in all physical and biochemical properties tested. The pH optimum of the enzyme acting on fructan polymers was 5.5, with a significant amount of activity remaining at pH 4.0. The optimum pH for sucrose degradation was broader and lower, with a peak at approximately 4.5.Enzyme activity was inhibited almost completely by Hg2' and Ag2+, inhibited partially by Cu2+, not inhibited by fluoride ion or Tris, and slightly stimulated by Mn2' and Co2+. Fructan polymers were attacked exohydrolytically by the enzyme, fructose being the only product released. With sufficient time, both levan and inulin were degraded to completion, with no evidence of product inhibition.Several bacteria which normally inhabit the human mouth, including Streptococcus mutans (2,3,12,18,38), S. salivarius (3, 12, 13, 33), S. sanguis (24), and Actinomyces viscosus (3, 49), can synthesize polymers of D-fructose. The structures of the fructans produced by many of these organisms have been analyzed, and it appears as though S. salivarius (3,12,13,32) and the actinomycetes (3, 49) produce a levan-type fructan, consisting predominantly of ,B(2->6)-linked fructosyl units with a significant degree of branching in the 1 position (13, 32). S. mutans, on the other hand, produces an inulin-type fructan which is made up almost exclusively of 1(2-l) linkages with some branching in the 6 position (2, 3, 12, 38). In some cases, the physical properties of the fructan polymers have been examined, and gene...

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confidence: 77%

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confidence: 98%

Expression, purification, and characterization of an exo-beta-D-fructosidase of Streptococcus mutans

et al. 1987

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“…From a biological standpoint, levan is known as a phytovirulence factor, providing a detoxifying barrier against plant defense compounds (5). It is also involved in dental plaque formation (6) and possesses antitumor activity (7). When attached to the bacterial cell wall, it produces a dense, slimy layer (capsule).…”

Section: Introductionmentioning

confidence: 99%

Viscoelastic Properties of Levan-DNA Mixtures Important in Microbial Biofilm Formation as Determined by Micro- and Macrorheology

Stojković

Sretenovic

Dogša

et al. 2015

Biophysical Journal

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We studied the viscoelastic properties of homogeneous and inhomogeneous levan-DNA mixtures using optical tweezers and a rotational rheometer. Levan and DNA are important components of the extracellular matrix of bacterial biofilms. Their viscoelastic properties influence the mechanical as well as molecular-transport properties of biofilm. Both macro- and microrheology measurements in homogeneous levan-DNA mixtures revealed pseudoplastic behavior. When the concentration of DNA reached a critical value, levan started to aggregate, forming clusters of a few microns in size. Microrheology using optical tweezers enabled us to measure local viscoelastic properties within the clusters as well as in the DNA phase surrounding the levan aggregates. In phase-separated levan-DNA mixtures, the results of macro- and microrheology differed significantly. The local viscosity and elasticity of levan increased, whereas the local viscosity of DNA decreased. On the other hand, the results of bulk viscosity measurements suggest that levan clusters do not interact strongly with DNA. Upon treatment with DNase, levan aggregates dispersed. These results demonstrate the advantages of microrheological measurements compared to bulk viscoelastic measurements when the materials under investigation are complex and inhomogeneous, as is often the case in biological samples.

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“…Oligosaccharides produced from levan by levanases are divided into two large groups : one is DFA IV (di-D-fructose 2,6h :2h6-dianhydrous) and the other is linear fructo-oligosaccharide. In addition to the use for the production of oligosaccharide, the levanase was also reported as potentially participating in the dental plaque mechanism in oral environments [14,15].…”

Section: Introductionmentioning

confidence: 99%

Purification and characterization of a levanbiose‐producing levanase from Pseudomonas sp. No. 43

Jung Kang,

Lee,

Lee

et al. 1999

Biotech and App Biochem

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A levanbiose‐accumulating levanase from Pseudomonas sp. No. 43 was purified to a homogeneous state by (NH4)2SO4 fractionation and by chromatography on DEAE‐Toyopearl 650 M and phenyl‐Toyopearl 650 M columns. The molecular mass and isoelectric point of the enzyme were estimated to be 36 kDa and 5.7 respectively; the optimal pH and temperature for the enzyme reaction were pH 7.0 and 40 °C respectively. The purified enzyme was stable in the pH range 6.0–8.0 at 20 °C and stable up to 50 °C at pH 7.0. The enzyme's activity was inhibited by MnCl2, CoCl2, AlCl3, EDTA and potassium permanganate. The levanase was specific towards the 2,6‐β‐D‐fructosidic linkages of levan and did not hydrolyse other polysaccharides among those examined. The enzyme is an exohydrolase of levan and produced levanbiose as a sole product; the limits of hydrolysis of levans from Zymomonas mobilis and Serratia sp. were 65% and 80% respectively.

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Production of Levan and Dextran in Plaque In Vivo

Abstract: Frequent eating of small amounts of sucrose for a period of three days resulted in the in vivo accumulation in plaque of about 1% dextran and about 3% levan.

Cited by 19 publications

References 6 publications

Expression, purification, and characterization of an exo-beta-D-fructosidase of Streptococcus mutans

Expression, purification, and characterization of an exo-beta-D-fructosidase of Streptococcus mutans

Viscoelastic Properties of Levan-DNA Mixtures Important in Microbial Biofilm Formation as Determined by Micro- and Macrorheology

Purification and characterization of a levanbiose‐producing levanase from Pseudomonas sp. No. 43

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