Variable importance in projection (VIP) plot displays the top 15 most important metabolite features identified by PLS-DA.

<p>Colored boxes on right indicate relative concentration of corresponding metabolite for samples biopsied from the bottom and top of chronic wounds. VIP is a weighted sum of squares of the PLS-DA loadings taking into account the amount of explained Y-variable in each dimension.</p

Mean abundance of major bacterial phyla for samples (n = 8) from clinical pressure ulcer wounds (n = 4).

<p>Mean abundance of major bacterial phyla for samples (n = 8) from clinical pressure ulcer wounds (n = 4).</p

Details of clinical subjects and chronic pressure ulcer wounds.

<p>*CP = cerebral palsy,</p><p>^ŧMR = mental retardation,</p><p>^§DVT = deep vein thrombosis,</p><p>^¶HSV = herpes simplex virus,</p><p>** = urinary tract infection</p><p>Details of clinical subjects and chronic pressure ulcer wounds.</p

Putative metabolic pathways associated with the wound environment of chronic pressure ulcers.

<p>Significantly contributing pathway nodes include glyoxylate and dicarboxylate metabolism. Highlighted metabolites indicated hits from the metabolic profiling and are coded according to p-value. Pathway maps are generated using the KEGG reference map (<a href="http://www.kegg.jp/kegg/pathway.html" target="_blank">http://www.kegg.jp/kegg/pathway.html</a>).</p

Correlation between the bacterial microbiome and metabolome in chronic pressure ulcer wounds.

<p>Nonparametric Spearman rank correlation was used to quantify the association between the relative abundance of bacterial genera and metabolite concentration in chronic pressure ulcer wounds. Major genera observed across wound samples are shown (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126735#pone.0126735.g003" target="_blank">Fig 3</a>) with phylum Firmicutes (purple), phylum Proteobacteria (red), and phylum Actinobacteria (green) clustered together. Correlation coefficient threshold of significance is set at 0.700 and p-values ≤ 0.05.</p

Scores plot of 3D PLS-DA statistically clusters chronic wound samples based on depth of biopsy.

<p>Red triangles indicates sections from the bottom of the wound biopsy and green crosses indicates sections from the top of the wound biopsy. 49.6% of the variance observed in the matrix of metabolite profiles is explained by the first 3 components.</p

Heatmap visualization.

<p>Heatmap was constructed based on clustering results from metabolite profiles of chronic pressure ulcer biopsies sectioned into top (green) and bottom (red) samples. Heatmap features the top twenty-five metabolite features as identified by t-test analysis (p≤0.05). Distance measure is by Pearson correlation and clustering is determined using the Ward algorithm.</p

Putative metabolic pathways associated with the wound environment of chronic pressure ulcers.

<p>Metabolome summary of pathway analysis. Mapping of the relative concentration of metabolites to the metabolome indicates impact contribution of metabolic pathways. Node color indicates significance based on p-value and node size indicates significance of pathway impact. Significantly impacted pathways include (a) inositol phosphate metabolism, (b) glyoxylate and dicarboxylate metabolism, (c) alanine, aspartate, and glutamate metabolism, (d) arginine and proline metabolism, (e) glycine, serine, and threonine metabolism, (f) pyruvate metabolism, and (g) citric acid cycle (TCA). The metabolic pathways are arranged according to the scores from the enrichment analysis (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126735#pone.0126735.g004" target="_blank">Fig 4</a>) (Y-axis) and from the topology analysis (X-axis).</p

Relative abundance of major bacterial genera for chronic pressure ulcer biopsy samples harvested from the top (T) and bottom (B) of the wounds.

<p>Relative abundance of major bacterial genera for chronic pressure ulcer biopsy samples harvested from the top (T) and bottom (B) of the wounds.</p

Two dimensional principal component analysis (2D PCA) scores plot demonstrates statistical clustering of top (T) and bottom (B) biopsies of the same wounds (n = 4) rather than statistical clustering dependent on biopsy depth based on analysis of relative bacterial abundance.

<p>Two dimensional principal component analysis (2D PCA) scores plot demonstrates statistical clustering of top (T) and bottom (B) biopsies of the same wounds (n = 4) rather than statistical clustering dependent on biopsy depth based on analysis of relative bacterial abundance.</p