Genes identified for the reductive and oxidative pathway in the anaerobic metabolism of glycerol.

<p>Comparison of genes from <i>Klebsiella pneumoniae</i> to <i>B</i>.<i>intermedia</i>, <i>D</i>. <i>alkenivorans</i>, <i>H</i>. <i>jeotgali</i>, <i>Hyphomicrobium sp</i>., <i>I</i>. <i>polytropus</i>, <i>M</i>. <i>loti</i> and <i>M</i>. <i>opportunistum</i>.</p

Genomic organization of the reductive pathway.

<p>(A) Orthologous <i>dha</i> genes (in grey) are represented by block arrows showing their position and orientation (out of scale). Gene arrangement is conserved in the seven organisms shown. <i>Mesorhizobium</i>, <i>Mycobacterium</i> and <i>Hyphomicrobium</i> have fused <i>dhaB1</i> and <i>dhaB2</i> genes. (B) Fusobacterium <i>I</i>. <i>polytropus</i> contains two <i>dha</i> regulons: genes coding for GDHt B12-dependent and its reactivation factor (grey arrows) are found in the plasmid or in the genome; and those coding for B12-independent (red arrows) are present in the genome. (C) Partial sequence alignment of the B12-independent glycerol dehydratase large subunit showing a highly conserved region corresponding to a glycyl radical domain.</p

Distribution of <i>dha</i> genes in completely sequenced Bacteria and Archaea genomes.

<p>On top, the genomic arrangement of <i>dha</i> genes present in <i>Klebsiella pneumoniae</i> is depicted; arrows indicate the direction of transcription. In parenthesis by the side of each taxonomic group, the number of total genomes analyzed within each group is given. Taxonomic groups in which <i>dha</i> genes were identified are depicted by rectangular boxes; the numbers inside indicate the number of genomes with “the complete pathway /at least one gene”, either reductive (A) or oxidative (B).</p

Glycerol assimilation through the fermentative pathway, showing the oxidative and reductive pathways.

<p>In the oxidative route, glycerol is converted in dihydroxyacetone (DHA) and dihydroxyacetone phosphate (DHA-P) by the products of <i>dhaD</i> and <i>dhaMKL</i> genes. In the reductive branch, glycerol is reduced to 1,3-PD by the successive action of glycerol dehydratase (GDHt) (encoded by three <i>dhaB</i> genes) and 1,3 propanediol oxidoreductase (encoded by <i>dhaT</i> gene). The genes refer to those found in <i>K</i>. <i>pneumoniae</i>.</p

Evolutionary history of <i>dha</i> genes.

<p>Maximum-likelihood phylogenetic tree of concatenated <i>dhaB1</i>, <i>dhaB2</i>, <i>dhaB3</i>, <i>dhaF</i> and <i>dhaG</i> genes. Numbers at the nodes indicate the percentage of bootstrap support (upper values for the ML tree and lower values for the NJ tree; only number above 50% are shown). Nodes with less than 50% bootstrap support are condensed. Colors depict different taxonomic groups: Proteobacteria (blue), Firmicutes (red), Spirochaetes (purple), Fusobacteria (green), Actinobacteria (orange), Synergistetes (brown).</p