Degradation and fermentation of α‐gluco‐oligosaccharides by bacterial strains from human colon: <i>in vitro</i> and <i>in vivo</i> studies in gnotobiotic rats

Djouzi, Zakia; Andrieux, C.P.; Pelenc, V.; Somarriba, S.; Popot, F.; Paul, F.; Monsan, Pierre; Szylit, Odette

doi:10.1111/j.1365-2672.1995.tb00924.x

Cited by 95 publications

(66 citation statements)

References 27 publications

(23 reference statements)

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“…Bacteroides fragilis-type bacteria are a prevalent group in the human gut microbial community, and they produce substantial amounts of propionate from succinate and fumarate (61). Previous in vitro and in vivo studies show that Bacteroides thetaiotamicron is highly efficient in utilizing ␣-1,2 and ␣-1,6 glycosidic linkages in ␣-glucooligosaccharides (15). A number of bacterial groups could be implicated in propionate production, including clostridia.…”

Section: Discussionmentioning

confidence: 99%

“…These properties make this type of dextran an interesting candidate prebiotic (15). Indeed, according to some studies, these glucooligosaccharides are metabolized by certain species of beneficial intestinal flora, e.g., bifidobacteria, lactobacilli, and particularly Bacteroides, and they are poorly metabolized by potentially detrimental strains (14,15). Chung and Day have shown that branched-chain glucooligosaccharides produced using Leuconostoc mesenteroides B-742 are readily utilized by bifidobacteria and lactobacilli but not by Salmonella spp.…”

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confidence: 99%

“…Such ␣-1,2 glycosidic linkages present at or near the nonreducing end result in high resistance to hydrolysis by digestive enzymes in both humans and animals (58). These properties make this type of dextran an interesting candidate prebiotic (15). Indeed, according to some studies, these glucooligosaccharides are metabolized by certain species of beneficial intestinal flora, e.g., bifidobacteria, lactobacilli, and particularly Bacteroides, and they are poorly metabolized by potentially detrimental strains (14,15).…”

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In VitroFermentation of Linear and α-1,2-Branched Dextrans by the Human Fecal Microbiota

Sarbini

Kolida

Naeye³

et al. 2011

Appl Environ Microbiol

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The role of structure and molecular weight in fermentation selectivity in linear ␣-1,6 dextrans and dextrans with ␣-1,2 branching was investigated. Fermentation by gut bacteria was determined in anaerobic, pH-controlled fecal batch cultures after 36 h. Inulin (1%, wt/vol), which is a known prebiotic, was used as a control. Samples were obtained at 0, 10, 24, and 36 h of fermentation for bacterial enumeration by fluorescent in situ hybridization and short-chain fatty acid analyses. The gas production of the substrate fermentation was investigated in non-pHcontrolled, fecal batch culture tubes after 36 h. Linear and branched 1-kDa dextrans produced significant increases in Bifidobacterium populations. The degree of ␣-1,2 branching did not influence the Bifidobacterium populations; however, ␣-1,2 branching increased the dietary fiber content, implying a decrease in digestibility. Other measured bacteria were unaffected by the test substrates except for the Bacteroides-Prevotella group, the growth levels of which were increased on inulin and 6-and 70-kDa dextrans, and the Faecalibacterium prausnitzii group, the growth levels of which were decreased on inulin and 1-kDa dextrans. A considerable increase in short-chain fatty acid concentration was measured following the fermentation of all dextrans and inulin. Gas production rates were similar among all dextrans tested but were significantly slower than that for inulin. The linear 1-kDa dextran produced lower total gas and shorter time to attain maximal gas production compared to those of the 70-kDa dextran (branched) and inulin. These findings indicate that dextrans induce a selective effect on the gut flora, short-chain fatty acids, and gas production depending on their length.

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Section: Discussionmentioning

confidence: 99%

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In VitroFermentation of Linear and α-1,2-Branched Dextrans by the Human Fecal Microbiota

Sarbini

Kolida

Naeye³

et al. 2011

Appl Environ Microbiol

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“…The ␣-1,2 GOS series consists of ␣-1,6 GOS bearing an additional glucosyl residue linked by an ␣-1,2 linkage at the nonreducing end of the molecule or at the branching points. GOS containing ␣-1,2 linkages are resistant to enzymatic digestion in animals and humans and have been shown to possess prebiotic properties (3,20,22,25). They are commercialized for application in animal and human nutrition, as well as in dermocosmetics.…”

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Role of the Two Catalytic Domains of DSR-E Dextransucrase and Their Involvement in the Formation of Highly α-1,2 Branched Dextran

et al. 2005

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The dsrE gene from Leuconostoc mesenteroides NRRL B-1299 was shown to encode a very large protein with two potentially active catalytic domains (CD1 and CD2) separated by a glucan binding domain (GBD). From sequence analysis, DSR-E was classified in glucoside hydrolase family 70, where it is the only enzyme to have two catalytic domains. The recombinant protein DSR-E synthesizes both ␣-1,6 and ␣-1,2 glucosidic linkages in transglucosylation reactions using sucrose as the donor and maltose as the acceptor. To investigate the specific roles of CD1 and CD2 in the catalytic mechanism, truncated forms of dsrE were cloned and expressed in Escherichia coli. Gene products were then small-scale purified to isolate the various corresponding enzymes. Dextran and oligosaccharide syntheses were performed. Structural characterization by 13 C nuclear magnetic resonance and/or high-performance liquid chromatography showed that enzymes devoid of CD2 synthesized products containing only ␣-1,6 linkages. On the other hand, enzymes devoid of CD1 modified ␣-1,6 linear oligosaccharides and dextran acceptors through the formation of ␣-1,2 linkages. Therefore, each domain is highly regiospecific, CD1 being specific for the synthesis of ␣-1,6 glucosidic bonds and CD2 only catalyzing the formation of ␣-1,2 linkages. This finding permitted us to elucidate the mechanism of ␣-1,2 branching formation and to engineer a novel transglucosidase specific for the formation of ␣-1,2 linkages. This enzyme will be very useful to control the rate of ␣-1,2 linkage synthesis in dextran or oligosaccharide production.From sucrose, Leuconostoc mesenteroides NRRL B-1299 produces a very uncommon dextran containing 61% ␣-1,6 glucosidic linkages in the linear chain and 28% ␣-1,2 linkages at branching points (11). The dextransucrase catalyzing the formation of this unusual dextran also produces glucooligosaccharides (GOS) by acceptor reaction. In the presence of a maltose acceptor, the glucosyl moiety of sucrose is transferred to maltose at the cost of polymer synthesis. This results in the formation of two different GOS families: the ␣-1,6 GOS series and the ␣-1,2 GOS series (5). The ␣-1,6 GOS series includes linear GOS possessing only ␣-1,6 linkages and a maltose residue at the reducing end. These oligosaccharides can also be produced by L. mesenteroides NRRL B-512F dextransucrase (12). The ␣-1,2 GOS series consists of ␣-1,6 GOS bearing an additional glucosyl residue linked by an ␣-1,2 linkage at the nonreducing end of the molecule or at the branching points. GOS containing ␣-1,2 linkages are resistant to enzymatic digestion in animals and humans and have been shown to possess prebiotic properties (3,20,22,25). They are commercialized for application in animal and human nutrition, as well as in dermocosmetics.To investigate the mechanism of highly ␣-1,2 branched dextran and GOS formation, three genes from L. mesenteroides

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“…These ␣-1,2 gluco-oligosaccharides resist hydrolysis by digestive enzymes in animals and humans because of the configuration of their osidic bonds and selectively stimulate intestinal microflora such as Bifidobacterium sp., Lactobacillus sp., or Bacteroides sp. (10,58). Thus, these molecules correspond to the definition of prebiotic agents which are food ingredients that are potentially beneficial to the health of consumers (44).…”

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Molecular Characterization of DSR-E, an α-1,2 Linkage-Synthesizing Dextransucrase with Two Catalytic Domains

et al. 2002

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A novel Leuconostoc mesenteroides NRRL B-1299 dextransucrase gene, dsrE, was isolated, sequenced, and cloned in Escherichia coli, and the recombinant enzyme was shown to be an original glucansucrase which catalyses the synthesis of ␣-1,6 and ␣-1,2 linkages. The nucleotide sequence of the dsrE gene consists of an open reading frame of 8,508 bp coding for a 2,835-amino-acid protein with a molecular mass of 313,267 Da. This is twice the average mass of the glucosyltransferases (GTFs) known so far, which is consistent with the presence of an additional catalytic domain located at the carboxy terminus of the protein and of a central glucan-binding domain, which is also significantly longer than in other glucansucrases. From sequence comparison with family 70 and ␣-amylase enzymes, crucial amino acids involved in the catalytic mechanism were identified, and several original sequences located at some highly conserved regions in GTFs were observed in the second catalytic domain.Glucansucrase enzymes from oral streptococci, Leuconostoc mesenteroides strains, and some Lactobacillus and Neisseria sp. catalyze the transfer of glucosyl residues from sucrose to synthesize ␣-D-glucopyranosyl homopolymers and oligomers. When sucrose is the sole substrate, high-molecular-weight polymers are obtained. Depending on the glucansucrase-producing strain, the synthesized glucans differ in size and structure. When efficient acceptors, such as maltose or isomaltose, are added to the reaction medium, glucansucrases catalyze the synthesis of low-molecular-weight oligosaccharides and the regiospecificity of several dextransucrases (type of linkages) from the Leuconostoc genus is conserved in oligosaccharide synthesis (8,13,41,45).To date, 17 glucosyltransferase (GTF)-encoding genes from Streptococcus spp., 8 glucansucrase-encoding genes from L. mesenteroides, and 1 gene from Lactobacillus reuteri have been cloned (for reviews, see references 3, 16, 32, and 59). Sequence information shows that they are closely related and share a common structure. These genes code for large enzymes with an average molecular mass of 160,000 Da composed of two main domains: an N-terminal conserved catalytic core of about 900 amino acids and a C-terminal domain covering 300 to 400 residues thought to be responsible for glucan binding and constituted by a series of repeated units (32). In addition, biochemical studies revealed that glucansucrases share many mechanistic features with amylolytic enzymes (15). Structural homologies were later confirmed by amino acid sequence comparison with glucoside hydrolases from family 13 (20). In family 13, the catalytic domain is formed of eight ␤-sheets alternating with eight ␣-helices, conferring a (␤/␣) 8 barrel structure (55). Two structure predictions (9, 26) concluded that glucansucrase enzymes also possess a catalytic (␤/␣) 8 barrel domain. However, MacGregor et al. (26) observed that well-recognized sequence segments appear in a different order, which tends to show that the ␤/␣ barrel elements are circularly permutate...

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Degradation and fermentation of α‐gluco‐oligosaccharides by bacterial strains from human colon: in vitro and in vivo studies in gnotobiotic rats

Cited by 95 publications

References 27 publications

In VitroFermentation of Linear and α-1,2-Branched Dextrans by the Human Fecal Microbiota

In VitroFermentation of Linear and α-1,2-Branched Dextrans by the Human Fecal Microbiota

Role of the Two Catalytic Domains of DSR-E Dextransucrase and Their Involvement in the Formation of Highly α-1,2 Branched Dextran

Molecular Characterization of DSR-E, an α-1,2 Linkage-Synthesizing Dextransucrase with Two Catalytic Domains

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