HISA big data in biomedicine and healthcare 2013 conference

Additional file 5. Biofilm formation by the S. suis serotype 2 (S2) and serotype 9 (S9) wild-type and agI/II -deficient mutant strains in the absence of porcine fibrinogen. Biofilm formation capacity was quantified after 24 h of incubation at 37 °C in the absence of porcine fibrinogen. Data represent the mean ± SEM from at least three independent experiments

Absence of capsular polysaccharide is associated with increased surface hydrophobicity of <i>S</i>. <i>suis</i> serotype 2.

<p>Hydrophobicity of wild-type and mutant strains was determined using <i>n</i>-hexadecane. Data represent the mean ± SEM from three independent experiments. *** (<i>p</i> < 0.001) indicates a significant difference between wild-type strains (P1/7 or 89–1591) and their non-encapsulated mutants (Δ<i>cpsF</i> and Δ<i>neuC</i>).</p

Strain-dependent role of the capsular polysaccharide in <i>S</i>. <i>suis</i> serotype 2 resistance to phagocytosis by dendritic cells (DCs).

<p>Internalization kinetics (0.5 to 4 h) of wild-type and non-encapsulated mutant strains by DCs. Data represent the mean ± SEM from four independent experiments. * (<i>p</i> < 0.05) and ** (<i>p</i> < 0.01) indicate a significant difference between P1/7 and P1/<i>7</i>Δ<i>cpsF</i> or P1/<i>7</i>Δ<i>neuC</i>.</p

Capsular polysaccharide is required for virulence of the <i>S</i>. <i>suis</i> serotype 2 ST25 strain 89–1591 in a mouse model of infection and persistence in blood.

<p>Survival (A) and blood bacterial burden 24 h post-infection (B) of CD-1 mice following intraperitoneal inoculation of 5 x 10⁷ CFU of wild-type strain 89–1591 or its non-encapsulated mutants 89-1591Δ<i>cpsF</i> and 89-1591Δ<i>neuC</i>. Data represent the survival curves (A) or geometric mean (B) of 15 mice/strain. *** (<i>p</i> < 0.001) indicates a significant difference between survival or blood bacterial burden of mice infected with wild-type strain 89–1591 and those infected with non-encapsulated mutants (89-1591Δ<i>cpsF</i> and 89–1591Δ<i>neuC</i>).</p

List of strains and plasmids used in this study.

<p>List of strains and plasmids used in this study.</p

Strain-dependent role of capsular polysaccharide in interference of <i>S</i>. <i>suis</i> serotype 2-induced cytokine production by dendritic cells (DCs).

<p>Cytokine production by DCs following infection with wild-type and non-encapsulated mutant strains after 16 h of incubation, as measured by ELISA, with the exception of IFN-β, after 6 h of incubation, by RT-qPCR. Production of TNF (A), IL-6 (B), IL-12p70 (C), CXCL1 (D), and IFN-β (E). Data represent the mean ± SEM from four independent experiments. C- denotes the negative control (cells in medium alone). *** (<i>p</i> < 0.001) indicates a significant difference between P1/7 and P1/<i>7</i>Δ<i>cpsF</i> or P1/<i>7</i>Δ<i>neuC</i>.</p

List of oligonucleotide primers used in this study.

<p>List of oligonucleotide primers used in this study.</p

The <i>S</i>. <i>suis</i> serotype 2 capsular polysaccharide is required for resisting the bactericidal effect of whole blood regardless of strain background.

<p>Capacity of wild-type strains and non-encapsulated mutants to resist the bactericidal effect of murine whole blood after 4 h of incubation. Percentage of bacterial killing was calculated in comparison to bacteria in plasma alone. Data represent the mean ± SEM from four independent experiments. n.d. denotes not detected. *** (<i>p</i> < 0.001) indicates a significant difference between wild-type strains (P1/7 or 89–1591) and their mutants (Δ<i>cpsF</i> or Δ<i>neuC</i>).</p

Deletion of genes involved in <i>S</i>. <i>suis</i> serotype 2 capsular polysaccharide biosynthesis (<i>cpsF</i> and <i>neuC</i>) results in non-encapsulation of the ST25 strain 89–1591.

<p>Transmission electron microscopy following labelling with polycationic ferritin of the ST25 wild-type strain 89–1591 (A) or its isogenic mutants 89–1591Δ<i>cpsF</i> (B) and 89–1591Δ<i>neuC</i> (C). Black bars = 1 μm.</p

The <i>S</i>. <i>suis</i> serotype 2 dipeptidyl peptidase IV is not involved in adhesion to porcine tracheal epithelial cells, regardless of the sequence type (ST) of the strain used, unlike the autolysin.

<p>Adhesion of different wild-type strains and dipeptidyl peptidase IV (DPPIV)- or autolysin (Atl)-deficient mutants to porcine epithelial cells was evaluated after 2 h of incubation with bacteria (MOI = 10). Results are expressed as mean ± SEM obtained from three independent experiments and represent the percentage of adhered inoculum. # indicates a significant difference (<i>p</i> < 0.01) between the wild-type ST1 strain P1/7 and ST25 strain 89–1591; *** (<i>p</i> < 0.001) between the wild-type strain and its Atl-deficient mutant.</p