Morphological Detection of Filipin‐Sterol Complexes in the Cytoplasmic Membrane of Staphylococcal L‐Form

Nishiyama, Yayoi; Yamaguchi, Hideyo

doi:10.1111/j.1348-0421.1990.tb00988.x

Cited by 9 publications

(5 citation statements)

References 30 publications

(43 reference statements)

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“…Interestingly, cholesterol, cholesteryl esters, and triglycerides (all serum lipids) have been reported to be a component of the lipids of S. aureus L-forms, although the content of PCs, PEs, and SMs was not examined (53). Nishiyama and Yamaguchi reported electron microscopic detection of complexes between the sterol-specific antibiotic filipin and cholesterol in the membrane of staphylococcal L-forms (54). Thus, the presence of cholesterol in L-forms is a precedent for our finding of this mammalian serum lipid in S. aureus cells and in their membranes.…”

Section: Discussionmentioning

confidence: 99%

Lipidomic and Ultrastructural Characterization of the Cell Envelope of Staphylococcus aureus Grown in the Presence of Human Serum

Hines

Alvarado

Chen

et al. 2020

mSphere

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Staphylococcus aureus can incorporate exogenous straight-chain unsaturated and saturated fatty acids (SCUFAs and SCFAs, respectively) to replace some of the normally biosynthesized branched-chain fatty acids and SCFAs. In this study, the impact of human serum on the S. aureus lipidome and cell envelope structure was comprehensively characterized. When S. aureus was grown in the presence of 20% human serum, typical human serum lipids, such as cholesterol, sphingomyelin, phosphatidylethanolamines, and phosphatidylcholines, were present in the total lipid extracts. Mass spectrometry showed that SCUFAs were incorporated into all major S. aureus lipid classes, i.e., phosphatidylglycerols, lysyl-phosphatidylglycerols, cardiolipins, and diglucosyldiacylglycerols. Heat-killed S. aureus retained fewer serum lipids and failed to incorporate SCUFAs, suggesting that association and incorporation of serum lipids with S. aureus require a living or nondenatured cell. Cytoplasmic membranes isolated from lysostaphin-produced protoplasts of serum-grown cells retained serum lipids, but washing cells with Triton X-100 removed most of them. Furthermore, electron microscopy studies showed that serum-grown cells had thicker cell envelopes and associated material on the surface, which was partially removed by Triton X-100 washing. To investigate which serum lipids were preferentially hydrolyzed by S. aureus lipases for incorporation, we incubated individual serum lipid classes with S. aureus and found that cholesteryl esters (CEs) and triglycerides (TGs) are the major donors of the incorporated fatty acids. Further experiments using purified Geh lipase confirmed that CEs and TGs were the substrates of this enzyme. Thus, growth in the presence of serum altered the nature of the cell surface with implications for interactions with the host. IMPORTANCE Comprehensive lipidomics of S. aureus grown in the presence of human serum suggests that human serum lipids can associate with the cell envelope without being truly integrated into the lipid membrane. However, fatty acids derived from human serum lipids, including unsaturated fatty acids, can be incorporated into lipid classes that can be biosynthesized by S. aureus itself. Cholesteryl esters and triglycerides are found to be the major source of incorporated fatty acids upon hydrolysis by lipases. These findings have significant implications for the nature of the S. aureus cell surface when grown in vivo. Changes in phospholipid and glycolipid abundances and fatty acid composition could affect membrane biophysics and function and the activity of membrane-targeting antimicrobials. Finally, the association of serum lipids with the cell envelope has implications for the physicochemical nature of the cell surface and its interaction with host defense systems.

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Section: Discussionmentioning

confidence: 99%

Lipidomic and Ultrastructural Characterization of the Cell Envelope of Staphylococcus aureus Grown in the Presence of Human Serum

Hines

Alvarado

Chen

et al. 2020

mSphere

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“…Interestingly, cholesterol, cholesteryl esters, and triglycerides (all serum lipids) have been reported to be a component of the lipids of S. aureus L-forms although the content of PCs, PEs, and SMs was not examined (47). Nishiyama and Yamaguchi reported electron microscopic detection of complexes between the sterol-specific antibiotic filipin and cholesterol in the membrane of staphylococcal L-forms (48). Thus, the presence of cholesterol in L-forms is a precedent for our finding of this mammalian serum lipid in S. aureus cells and in their membranes.…”

Section: Discussionmentioning

confidence: 99%

Lipidomic and Ultrastructural Characterization of Cell Envelope ofStaphylococcus aureusGrown in the Presence of Human Serum

Hines

Alvarado

Chen

et al. 2020

Preprint

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26Staphylococcus aureus can incorporate exogenous straight-chain unsaturated and 27 saturated fatty acids (SCUFAs and SCFAs, respectively) to replace some of the normally 28 biosynthesized branched-chain fatty acids and SCFAs. In this study, the impact of human serum 29 on the S. aureus lipidome and cell envelope structure was comprehensively characterized. When 30 grown in the presence of 20% human serum, typical human serum lipids, such as cholesterol, 31 sphingomyelin, phosphatidylethanolamines, and phosphatidylcholines, were present in the total 32 lipid extracts. Mass spectrometry showed that SCUFAs were incorporated into all major S. 33 aureus lipid classes, i.e., phosphatidylglycerols, lysyl-phosphatidylglycerols, cardiolipins, and 34 diglucosyldiacylglycerols. Heat-killed S. aureus retained much fewer serum lipids and failed to 35 incorporate SCUFAs, suggesting that association and incorporation of serum lipids with S. 36 aureus requires a living or non-denatured cell. Cytoplasmic membranes isolated from 37 lysostaphin-produced protoplasts of serum-grown cells retained serum lipids, but washing cells 38 with Triton X-100 removed most of them. Furthermore, electron microscopy studies showed that 39 serum-grown cells had thicker cell envelopes and associated material on the surface, which was 40 partially removed by Triton X-100 washing. To investigate which serum lipids were 41 preferentially hydrolyzed by S. aureus lipases for incorporation, we incubated individual serum 42 lipid classes with S. aureus and found that cholesteryl esters (CEs) and triglycerides (TGs) are 43 the major donors of the incorporated fatty acids. Further experiments using purified Geh lipase 44 confirmed CEs and TGs being the substrates of this enzyme. Thus, growth in the presence of 45 serum altered the nature of the cell surface with implications for interactions with the host. 46 Page 3 of 38 IMPORTANCE 47Comprehensive lipidomics of S. aureus grown in the presence of human serum suggests 48 human serum lipids can associate with the cell envelope without being truly integrated into the 49 lipid membrane. However, fatty acids-derived from human serum lipids, including unsaturated 50 fatty acids, can be incorporated into lipid classes that can be biosynthesized by S. aureus itself. 51Cholesteryl esters and triglycerides are found to be the major source of incorporated fatty acids 52 upon hydrolysis by lipases. These findings have significant implications for the nature of the S. 53 aureus cell surface when grown in vivo. Changes in phospholipid and glycolipid abundances and 54 fatty acid composition could affect membrane biophysics and function and the activity of 55 membrane-targeting antimicrobials. Finally, the association of serum lipids with the cell envelope 56 has implications for the physicochemical nature of the cell surface and its interaction with host 57 defense systems. 58 KEYWORDS 59 Lipidomics, human serum lipids, fatty acid incorporation, lipid association, cell envelope 60 structure 61 62 63 64 65 6...

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“…However, cell-wall-deficient forms of S. aureus , called L-forms, do exist [ 65 ]. As staphylococcal L-forms lack cell walls, sterols provide a means of maintaining structural integrity and fluidity [ 66 ]. More importantly, the presence of sterols has been linked to increased resistance to antimicrobial peptides [ 67 ] and lipid raft formation, demonstrating their importance in membrane function and biological processes.…”

Section: Resultsmentioning

confidence: 99%

Low-THz Vibrations of Biological Membranes

et al. 2023

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A growing body of work has linked key biological activities to the mechanical properties of cellular membranes, and as a means of identification. Here, we present a computational approach to simulate and compare the vibrational spectra in the low- THz region for mammalian and bacterial membranes, investigating the effect of membrane asymmetry and composition, as well as the conserved frequencies of a specific cell. We find that asymmetry does not impact the vibrational spectra, and the impact of sterols depends on the mobility of the components of the membrane. We demonstrate that vibrational spectra can be used to distinguish between membranes and, therefore, could be used in identification of different organisms. The method presented, here, can be immediately extended to other biological structures (e.g., amyloid fibers, polysaccharides, and protein-ligand structures) in order to fingerprint and understand vibrations of numerous biologically-relevant nanoscale structures.

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Morphological Detection of Filipin‐Sterol Complexes in the Cytoplasmic Membrane of Staphylococcal L‐Form

Cited by 9 publications

References 30 publications

Lipidomic and Ultrastructural Characterization of the Cell Envelope of Staphylococcus aureus Grown in the Presence of Human Serum

Lipidomic and Ultrastructural Characterization of the Cell Envelope of Staphylococcus aureus Grown in the Presence of Human Serum

Lipidomic and Ultrastructural Characterization of Cell Envelope ofStaphylococcus aureusGrown in the Presence of Human Serum

Low-THz Vibrations of Biological Membranes

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