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Characterization of the algC gene expression pattern in the multidrug resistant Acinetobacter baumannii AIIMS 7 and correlation with biofilm development on abiotic surface.

Sahu PK, Iyer PS, Barage SH, Sonawane KD, Chopade BA - ScientificWorldJournal (2014)

Bottom Line: Comparison revealed differential algC expression pattern with maximum 81.59-fold increase in biofilm cells versus 3.24-fold in planktonic cells (P < 0.05).Expression levels strongly correlated with specific biofilm stages (scale of 3 to 96 h), coinciding maximum at initial surface attachment stage (9 h) and biofilm maturation stage (48 h).Moreover, molecular dynamics analysis on the three-dimensional structure of PMM/PGM (simulated up to 10 ns) revealed enzyme structure as stable and similar to that in P. aeruginosa (synthesis of alginate and lipopolysaccharide core) and involved in constitution of biofilm EPS (extracellular polymeric substances).

View Article: PubMed Central - PubMed

Affiliation: Institute of Bioinformatics and Biotechnology, University of Pune, Pune 411 007, India ; Ispat General Hospital, SAIL, Rourkela 769 005, India.

ABSTRACT
Relative quantification of algC gene expression was evaluated in the multidrug resistant strain Acinetobacter baumannii AIIMS 7 biofilm (3 to 96 h, on polystyrene surface) compared to the planktonic counterparts. Comparison revealed differential algC expression pattern with maximum 81.59-fold increase in biofilm cells versus 3.24-fold in planktonic cells (P < 0.05). Expression levels strongly correlated with specific biofilm stages (scale of 3 to 96 h), coinciding maximum at initial surface attachment stage (9 h) and biofilm maturation stage (48 h). Cloning, heterologous expression, and bioinformatics analyses indicated algC gene product as the bifunctional enzyme phosphomannomutase/phosphoglucomutase (PMM/PGM) of ∼ 53 kDa size, which augmented biofilms significantly in algC clones compared to controls (lacking algC gene), further localized by scanning electron microscopy. Moreover, molecular dynamics analysis on the three-dimensional structure of PMM/PGM (simulated up to 10 ns) revealed enzyme structure as stable and similar to that in P. aeruginosa (synthesis of alginate and lipopolysaccharide core) and involved in constitution of biofilm EPS (extracellular polymeric substances). Our observation on differential expression pattern of algC having strong correlation with important biofilm stages, scanning electron-microscopic evidence of biofilm augmentation taken together with predictive enzyme functions via molecular dynamic (MD) simulation, proposes a new basis of A. baumannii AIIMS 7 biofilm development on inanimate surfaces.

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(a)–(c) Results from 10 ns molecular dynamics simulation performed on PMM/PGM model. (a) Root mean square deviation (RMSD); (b) radius of gyration; (c) root mean square fluctuation (RMSF).
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fig8: (a)–(c) Results from 10 ns molecular dynamics simulation performed on PMM/PGM model. (a) Root mean square deviation (RMSD); (b) radius of gyration; (c) root mean square fluctuation (RMSF).

Mentions: To verify the simulation stability and to measure structure and dynamics of PMM/PGM model of A. baumannii AIIMS 7, standard structural parameters like RMSD, root mean square fluctuation (RMSF), and radius of gyration (RG) were calculated and represented in Figures 8(a)–8(c). During molecular dynamics simulation period of 10 ns, the average RMSD value was 0.3 nm as depicted (Figure 8(a)). Steady RMSD result showed for the atoms in the four domains of PMM/PGM model indicated that the catalytic activity is relatively stable during the simulation. The result for radius of gyration (RG) also indicated the stability of model over the whole simulation period (Figure 8(b)). Minor fluctuations in C-alpha atoms (RMSF) of helical and sheet structural elements could be seen whereas loop region showed variability to some extent (Figure 8(c)). Overall, these results of RMSD, RMSF, and RG strongly indicated the stability of system over the entire simulation period.


Characterization of the algC gene expression pattern in the multidrug resistant Acinetobacter baumannii AIIMS 7 and correlation with biofilm development on abiotic surface.

Sahu PK, Iyer PS, Barage SH, Sonawane KD, Chopade BA - ScientificWorldJournal (2014)

(a)–(c) Results from 10 ns molecular dynamics simulation performed on PMM/PGM model. (a) Root mean square deviation (RMSD); (b) radius of gyration; (c) root mean square fluctuation (RMSF).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4269089&req=5

fig8: (a)–(c) Results from 10 ns molecular dynamics simulation performed on PMM/PGM model. (a) Root mean square deviation (RMSD); (b) radius of gyration; (c) root mean square fluctuation (RMSF).
Mentions: To verify the simulation stability and to measure structure and dynamics of PMM/PGM model of A. baumannii AIIMS 7, standard structural parameters like RMSD, root mean square fluctuation (RMSF), and radius of gyration (RG) were calculated and represented in Figures 8(a)–8(c). During molecular dynamics simulation period of 10 ns, the average RMSD value was 0.3 nm as depicted (Figure 8(a)). Steady RMSD result showed for the atoms in the four domains of PMM/PGM model indicated that the catalytic activity is relatively stable during the simulation. The result for radius of gyration (RG) also indicated the stability of model over the whole simulation period (Figure 8(b)). Minor fluctuations in C-alpha atoms (RMSF) of helical and sheet structural elements could be seen whereas loop region showed variability to some extent (Figure 8(c)). Overall, these results of RMSD, RMSF, and RG strongly indicated the stability of system over the entire simulation period.

Bottom Line: Comparison revealed differential algC expression pattern with maximum 81.59-fold increase in biofilm cells versus 3.24-fold in planktonic cells (P < 0.05).Expression levels strongly correlated with specific biofilm stages (scale of 3 to 96 h), coinciding maximum at initial surface attachment stage (9 h) and biofilm maturation stage (48 h).Moreover, molecular dynamics analysis on the three-dimensional structure of PMM/PGM (simulated up to 10 ns) revealed enzyme structure as stable and similar to that in P. aeruginosa (synthesis of alginate and lipopolysaccharide core) and involved in constitution of biofilm EPS (extracellular polymeric substances).

View Article: PubMed Central - PubMed

Affiliation: Institute of Bioinformatics and Biotechnology, University of Pune, Pune 411 007, India ; Ispat General Hospital, SAIL, Rourkela 769 005, India.

ABSTRACT
Relative quantification of algC gene expression was evaluated in the multidrug resistant strain Acinetobacter baumannii AIIMS 7 biofilm (3 to 96 h, on polystyrene surface) compared to the planktonic counterparts. Comparison revealed differential algC expression pattern with maximum 81.59-fold increase in biofilm cells versus 3.24-fold in planktonic cells (P < 0.05). Expression levels strongly correlated with specific biofilm stages (scale of 3 to 96 h), coinciding maximum at initial surface attachment stage (9 h) and biofilm maturation stage (48 h). Cloning, heterologous expression, and bioinformatics analyses indicated algC gene product as the bifunctional enzyme phosphomannomutase/phosphoglucomutase (PMM/PGM) of ∼ 53 kDa size, which augmented biofilms significantly in algC clones compared to controls (lacking algC gene), further localized by scanning electron microscopy. Moreover, molecular dynamics analysis on the three-dimensional structure of PMM/PGM (simulated up to 10 ns) revealed enzyme structure as stable and similar to that in P. aeruginosa (synthesis of alginate and lipopolysaccharide core) and involved in constitution of biofilm EPS (extracellular polymeric substances). Our observation on differential expression pattern of algC having strong correlation with important biofilm stages, scanning electron-microscopic evidence of biofilm augmentation taken together with predictive enzyme functions via molecular dynamic (MD) simulation, proposes a new basis of A. baumannii AIIMS 7 biofilm development on inanimate surfaces.

Show MeSH
Related in: MedlinePlus