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A Staphylococcus aureus ypfP mutant with strongly reduced lipoteichoic acid (LTA) content: LTA governs bacterial surface properties and autolysin activity.

Fedtke I, Mader D, Kohler T, Moll H, Nicholson G, Biswas R, Henseler K, Götz F, Zähringer U, Peschel A - Mol. Microbiol. (2007)

Bottom Line: The ypfP gene responsible for biosynthesis of a glycolipid found in LTA was deleted in Staphylococcus aureus SA113, causing 87% reduction of the LTA content.However, the autolytic activity of the mutant was strongly reduced demonstrating a role of LTA in controlling autolysin activity.Moreover, the hydrophobicity of the LTA mutant was altered and its ability to form biofilms on plastic was completely abrogated indicating a profound impact of LTA on physicochemical properties of bacterial surfaces.

View Article: PubMed Central - PubMed

Affiliation: Cellular and Molecular Microbiology Division, University of Tübingen, Department of Medical Microbiology and Hygiene, 72076 Tübingen, Germany.

ABSTRACT
Many Gram-positive bacteria produce lipoteichoic acid (LTA) polymers whose physiological roles have remained a matter of debate because of the lack of LTA-deficient mutants. The ypfP gene responsible for biosynthesis of a glycolipid found in LTA was deleted in Staphylococcus aureus SA113, causing 87% reduction of the LTA content. Mass spectrometry and nuclear magnetic resonance spectroscopy revealed that the mutant LTA contained a diacylglycerol anchor instead of the glycolipid, whereas the remaining part was similar to the wild-type polymer except that it was shorter. The LTA mutant strain revealed no major changes in patterns of cell wall proteins or autolytic enzymes compared with the parental strain indicating that LTA may be less important in S. aureus protein attachment than previously thought. However, the autolytic activity of the mutant was strongly reduced demonstrating a role of LTA in controlling autolysin activity. Moreover, the hydrophobicity of the LTA mutant was altered and its ability to form biofilms on plastic was completely abrogated indicating a profound impact of LTA on physicochemical properties of bacterial surfaces. We propose to consider LTA and its biosynthetic enzymes as targets for new antibiofilm strategies.

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Growth (A) and stationary-phase survival (B) curves of S. aureus strains. The numbers of live bacteria in cultures grown for 24 h were defined as 100% in (B). Data represent the means ± SD of three independent cultures (*P < 0.05; **P < 0.01 versus wild type; unpaired, two-tailed t-test).
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fig05: Growth (A) and stationary-phase survival (B) curves of S. aureus strains. The numbers of live bacteria in cultures grown for 24 h were defined as 100% in (B). Data represent the means ± SD of three independent cultures (*P < 0.05; **P < 0.01 versus wild type; unpaired, two-tailed t-test).

Mentions: The S. aureus SA113 ypfP mutant represents the first stable bacterial strain with strongly reduced LTA content thereby providing a means to study the role of LTA in basic bacterial processes. In vitro growth and survival behaviours of parental and mutant strains were compared. Surprisingly, growth rates of wild-type and mutant strain were indistinguishable (Fig. 5A) indicating that S. aureus in vitro growth is not dependent on normal LTA amounts. However, the SA113 ypfP mutant had a more than 10-fold reduced capacity to survive at late stationary phase after several days of incubation (Fig. 5B) while the corresponding RN4220 mutant, which lacks the glycolipid but contains normal amounts of LTA, did not show such a survival defect (Fig. 5). Therefore, the reduced ability of the SA113 ypfP mutant to cope with starvation seems to result from LTA depletion rather than lack of the glycolipid. In contrast to the S. aureus RN4220 ypfP::cat mutant (Kiriukhin et al., 2001), none of our ΔypfP mutants showed defects in growth on Baird-Parker agar (data not shown).


A Staphylococcus aureus ypfP mutant with strongly reduced lipoteichoic acid (LTA) content: LTA governs bacterial surface properties and autolysin activity.

Fedtke I, Mader D, Kohler T, Moll H, Nicholson G, Biswas R, Henseler K, Götz F, Zähringer U, Peschel A - Mol. Microbiol. (2007)

Growth (A) and stationary-phase survival (B) curves of S. aureus strains. The numbers of live bacteria in cultures grown for 24 h were defined as 100% in (B). Data represent the means ± SD of three independent cultures (*P < 0.05; **P < 0.01 versus wild type; unpaired, two-tailed t-test).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2169524&req=5

fig05: Growth (A) and stationary-phase survival (B) curves of S. aureus strains. The numbers of live bacteria in cultures grown for 24 h were defined as 100% in (B). Data represent the means ± SD of three independent cultures (*P < 0.05; **P < 0.01 versus wild type; unpaired, two-tailed t-test).
Mentions: The S. aureus SA113 ypfP mutant represents the first stable bacterial strain with strongly reduced LTA content thereby providing a means to study the role of LTA in basic bacterial processes. In vitro growth and survival behaviours of parental and mutant strains were compared. Surprisingly, growth rates of wild-type and mutant strain were indistinguishable (Fig. 5A) indicating that S. aureus in vitro growth is not dependent on normal LTA amounts. However, the SA113 ypfP mutant had a more than 10-fold reduced capacity to survive at late stationary phase after several days of incubation (Fig. 5B) while the corresponding RN4220 mutant, which lacks the glycolipid but contains normal amounts of LTA, did not show such a survival defect (Fig. 5). Therefore, the reduced ability of the SA113 ypfP mutant to cope with starvation seems to result from LTA depletion rather than lack of the glycolipid. In contrast to the S. aureus RN4220 ypfP::cat mutant (Kiriukhin et al., 2001), none of our ΔypfP mutants showed defects in growth on Baird-Parker agar (data not shown).

Bottom Line: The ypfP gene responsible for biosynthesis of a glycolipid found in LTA was deleted in Staphylococcus aureus SA113, causing 87% reduction of the LTA content.However, the autolytic activity of the mutant was strongly reduced demonstrating a role of LTA in controlling autolysin activity.Moreover, the hydrophobicity of the LTA mutant was altered and its ability to form biofilms on plastic was completely abrogated indicating a profound impact of LTA on physicochemical properties of bacterial surfaces.

View Article: PubMed Central - PubMed

Affiliation: Cellular and Molecular Microbiology Division, University of Tübingen, Department of Medical Microbiology and Hygiene, 72076 Tübingen, Germany.

ABSTRACT
Many Gram-positive bacteria produce lipoteichoic acid (LTA) polymers whose physiological roles have remained a matter of debate because of the lack of LTA-deficient mutants. The ypfP gene responsible for biosynthesis of a glycolipid found in LTA was deleted in Staphylococcus aureus SA113, causing 87% reduction of the LTA content. Mass spectrometry and nuclear magnetic resonance spectroscopy revealed that the mutant LTA contained a diacylglycerol anchor instead of the glycolipid, whereas the remaining part was similar to the wild-type polymer except that it was shorter. The LTA mutant strain revealed no major changes in patterns of cell wall proteins or autolytic enzymes compared with the parental strain indicating that LTA may be less important in S. aureus protein attachment than previously thought. However, the autolytic activity of the mutant was strongly reduced demonstrating a role of LTA in controlling autolysin activity. Moreover, the hydrophobicity of the LTA mutant was altered and its ability to form biofilms on plastic was completely abrogated indicating a profound impact of LTA on physicochemical properties of bacterial surfaces. We propose to consider LTA and its biosynthetic enzymes as targets for new antibiofilm strategies.

Show MeSH
Related in: MedlinePlus