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Apeldoorn, Netherlands

Lutz M.,University Utrecht | Van Krieken J.,Purac
Acta Crystallographica Section C: Crystal Structure Communications | Year: 2010

The dimeric condensation product of lactic acid, namely (S,S)-2-[(2-hy-droxy-propano-yl)-oxy]propanoic acid, C6H 10O5, (I), crystallizes with two independent mol-ecules in the asymmetric unit, which both have an essentially planar backbone. The trimeric condensation product, namely (S,S,S)-3-hy-droxy-but-3-en-2-yl 2-[(2-hy-droxy-propano-yl)-oxy]propano-ate, C9H14O 7, (II), has one mol-ecule in the asymmetric unit and consists of two essentially planar parts, with the central C - O bond in a gauche conformation. Both mol-ecules of the dimer are involved in inter-molecular hydrogen bonds, forming chains with a C(8) graph set. These chains are connected by D(2) hydrogen bonds to form a two-dimensional layer. The trimer forms hydrogen-bonded C(10) and C22(6) chains, which together result in a two-dimensional motif. The Hooft method [Hooft, Straver & Spek (2008). J. Appl. Cryst. 41, 96-103] was successfully applied to the determination of the absolute structure of (I). © 2010 International Union of Crystallography. Source

Remus D.M.,TI Food and Nutrition | Remus D.M.,NIZO food research | Remus D.M.,Wageningen University | van Kranenburg R.,Purac | And 16 more authors.
Microbial Cell Factories | Year: 2012

Background: Bacterial cell surface-associated polysaccharides are involved in the interactions of bacteria with their environment and play an important role in the communication between pathogenic bacteria and their host organisms. Cell surface polysaccharides of probiotic species are far less well described. Therefore, improved knowledge on these molecules is potentially of great importance to understand the strain-specific and proposed beneficial modes of probiotic action.Results: The Lactobacillus plantarum WCFS1 genome encodes 4 clusters of genes that are associated with surface polysaccharide production. Two of these clusters appear to encode all functions required for capsular polysaccharide formation (cps2A-J and cps4A-J), while the remaining clusters are predicted to lack genes encoding chain-length control functions and a priming glycosyl-transferase (cps1A-I and cps3A-J). We constructed L. plantarum WCFS1 gene deletion mutants that lack individual (Δcps1A-I, Δcps2A-J, Δcps3A-J and Δcps4A-J) or combinations of cps clusters (Δcps1A-3J and Δcps1A-3I, Δcps4A-J) and assessed the genome wide impact of these mutations by transcriptome analysis. The cps cluster deletions influenced the expression of variable gene sets in the individual cps cluster mutants, but also considerable numbers of up- and down-regulated genes were shared between mutants in cps cluster 1 and 2, as well as between mutant in cps clusters 3 and 4. Additionally, the composition of overall cell surface polysaccharide fractions was altered in each mutant strain, implying that despite the apparent incompleteness of cps1A-I and cps3A-J, all clusters are active and functional in L. plantarum. The Δcps1A-I strain produced surface polysaccharides in equal amounts as compared to the wild-type strain, while the polysaccharides were characterized by a reduced molar mass and the lack of rhamnose. The mutants that lacked functional copies of cps2A-J, cps3A-J or cps4A-J produced decreased levels of surface polysaccharides, whereas the molar mass and the composition of polysaccharides was not affected by these cluster mutations. In the quadruple mutant, the amount of surface polysaccharides was strongly reduced. The impact of the cps cluster mutations on toll-like receptor (TLR)-mediated human nuclear factor (NF)-κB activation in host cells was evaluated using a TLR2 reporter cell line. In comparison to a L. plantarum wild-type derivative, TLR2 activation remained unaffected by the Δcps1A-I and Δcps3A-J mutants but appeared slightly increased after stimulation with the Δcps2A-J and Δcps4A-J mutants, while the Δcps1A-3J and Δcps1A-3J, Δcps4A-J mutants elicited the strongest responses and clearly displayed enhanced TLR2 signaling.Conclusions: Our study reveals that modulation of surface glycan characteristics in L. plantarum highlights the role of these molecules in shielding of cell envelope embedded host receptor ligands. Although the apparently complete cps clusters (cps2A-J and cps4A-J) contributed individually to this shielding, the removal of all cps clusters led to the strongest signaling enhancement. Our findings provide new insights into cell surface glycan biosynthesis in L. plantarum, which bears relevance in the context of host-cell signaling by probiotic bacteria. © 2012 Remus et al.; licensee BioMed Central Ltd. Source

Kovacs A.T.,University of Groningen | Van Hartskamp M.,Purac | Kuipers O.P.,University of Groningen | Kuipers O.P.,Kluyver Center for Genomics of Industrial Fermentation | Van Kranenburg R.,Purac
Applied and Environmental Microbiology | Year: 2010

Bacillus coagulans has good potential as an industrial production organism for platform chemicals from renewable resources but has limited genetic tools available. Here, we present a targeted gene disruption system using the Cre-lox system, development of a LacZ reporter assay for monitoring gene transcription, and heterologous D-lactate dehydrogenase expression. Copyright © 2010, American Society for Microbiology. All Rights Reserved. Source

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