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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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Related in: MedlinePlus

Pattern of biofilm growth of A. baumannii AIIMS 7. Graph showing corresponding biofilm indices of biofilms formed on polystyrene microtitre surface, calculated after normalization with control and plotted versus representative time points (three to 96 h).
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fig2: Pattern of biofilm growth of A. baumannii AIIMS 7. Graph showing corresponding biofilm indices of biofilms formed on polystyrene microtitre surface, calculated after normalization with control and plotted versus representative time points (three to 96 h).

Mentions: Biofilm growth pattern A. baumannii on polystyrene surface can be seen in Figure 2, which can be explained in three distinct stages. First, an exponential rate of increase was observed at 3 to 9 hours, which defined the initial attachment and micro-colony aggregation stage (Figure 2). After 9 hour till 36 hours it showed steady level of increase in biofilm indices, indicating the consolidation stage of the attached micro-colonies and approaching maturation of biofilm. Third, maximum production of biofilm matrix could be seen at 36 to 48 hours, marking the maturation stage. Lastly, as like the plateau phase in the planktonic growth curve of A. baumannii AIIMS 7 (data not shown), the biofilm growth pattern also exhibited a steady state and persistent nature after maturation (after 48 hour till 96 hours). To find the association of algC gene expression pattern at transcription level (as revealed from real-time PCR analysis) with that of biofilm growth, correlation coefficients were determined using the RQ values in biofilm samples and biofilm indices at corresponding time points. High correlation was observed at all three major stages of biofilm. Correlation coefficients were 0.902, 0.925, and 0.983 (P < 0.05) corresponding to initial attachment, consolidation of the surface-attached micro-aggregation, and maturation of biofilm stages. Correlation was found to be maximum (0.983, P < 0.05) at stages where biofilms were mature. This indicated a strong possibility that transcription of algC could be in close association with biofilm formation, especially the maturation stage (36–48 hours) and also the initial attachment stage (3–9 hours).


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)

Pattern of biofilm growth of A. baumannii AIIMS 7. Graph showing corresponding biofilm indices of biofilms formed on polystyrene microtitre surface, calculated after normalization with control and plotted versus representative time points (three to 96 h).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig2: Pattern of biofilm growth of A. baumannii AIIMS 7. Graph showing corresponding biofilm indices of biofilms formed on polystyrene microtitre surface, calculated after normalization with control and plotted versus representative time points (three to 96 h).
Mentions: Biofilm growth pattern A. baumannii on polystyrene surface can be seen in Figure 2, which can be explained in three distinct stages. First, an exponential rate of increase was observed at 3 to 9 hours, which defined the initial attachment and micro-colony aggregation stage (Figure 2). After 9 hour till 36 hours it showed steady level of increase in biofilm indices, indicating the consolidation stage of the attached micro-colonies and approaching maturation of biofilm. Third, maximum production of biofilm matrix could be seen at 36 to 48 hours, marking the maturation stage. Lastly, as like the plateau phase in the planktonic growth curve of A. baumannii AIIMS 7 (data not shown), the biofilm growth pattern also exhibited a steady state and persistent nature after maturation (after 48 hour till 96 hours). To find the association of algC gene expression pattern at transcription level (as revealed from real-time PCR analysis) with that of biofilm growth, correlation coefficients were determined using the RQ values in biofilm samples and biofilm indices at corresponding time points. High correlation was observed at all three major stages of biofilm. Correlation coefficients were 0.902, 0.925, and 0.983 (P < 0.05) corresponding to initial attachment, consolidation of the surface-attached micro-aggregation, and maturation of biofilm stages. Correlation was found to be maximum (0.983, P < 0.05) at stages where biofilms were mature. This indicated a strong possibility that transcription of algC could be in close association with biofilm formation, especially the maturation stage (36–48 hours) and also the initial attachment stage (3–9 hours).

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