Effects of membrane bilayer reorganizations on the 2103 cm−1 Raman spectral CD stretching mode linewidths in dimyristoyl phosphatidylcholine‐d54 (DMPC‐d54) liposomes

Bryant, Gail J.; Lavialle, Françoise; Levin, Ira W.

doi:10.1002/jrs.1250120205

Cited by 16 publications

(15 citation statements)

References 21 publications

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“…The symmetric and antisymmetric CD 2 stretching modes ( s CD 2 and a CD 2 ) arising from the deuterated fatty acid are observed at 2100 and 2175 cm Ϫ1 , respectively. This region also includes the symmetric CD 3 stretching mode ( s CD 3 ), which gives rise to two components at 2120 and 2075 cm Ϫ1 , this splitting being attributed to an interaction with the overtone of the asymmetric CD 3 deformation mode at 1058 cm Ϫ1 (Mendelsohn et al, 1976;Bryant et al, 1982). The C-H stretching region between 2750 and 3100 cm Ϫ1 shows a similar profile to those recorded for equimolar mixtures of ceramides and cholesterol.…”

Section: Resultssupporting

confidence: 52%

Direct Observation of Domains in Model Stratum Corneum Lipid Mixtures by Raman Microspectroscopy

Percot

Lafleur

2001

Biophysical Journal

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Several studies on intact and model stratum corneum (SC), the top layer of the epidermis, have suggested the presence of crystalline domains. In the present work, we used micro-Raman mapping to detect lipid domains in model lipid mixtures formed by an equimolar mixture of ceramides, cholesterol, and palmitic acid, the three main lipid species of SC. We were able to determine the spatial distribution of the three compounds individually based on the systematic analysis of band areas. As a control, we studied freeze-dried lipid mixtures, and the Raman microspectroscopy reported faithfully the homogeneous distribution of the three compounds. Spectral mapping was then performed on hydrated equimolar mixtures carefully annealed. In this case, clear phase separations were observed. Domains enriched in cholesterol, ceramides, or palmitic acid with a size of a few tens of square microns were detected. These findings constitute the first direct evidence of the formation of heterogeneous domains in the SC lipid models in a bulk phase. Raman microspectroscopy is an innovative approach to characterize the conditions leading to the formation of domains and provides new insights into the understanding of the skin barrier.

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Section: Resultssupporting

confidence: 52%

Direct Observation of Domains in Model Stratum Corneum Lipid Mixtures by Raman Microspectroscopy

Percot

Lafleur

2001

Biophysical Journal

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“…1 A and B). C-D X bonds of various types, including C-D 2 and symmetrical and asymmetrical C-D 3 bonds originating from various biomolecules, reportedly produce Raman bands between 2,013 and 2,300 cm −1 (38)(39)(40)(41)(42)(43)(44). Furthermore, modeling of the Raman peaks induced by the C-D X bond using deuterated palmitic acid as the model compound also predicted peaks in this region (SI Appendix, Fig.…”

Section: Resultsmentioning

confidence: 87%

Tracking heavy water (D ₂ O) incorporation for identifying and sorting active microbial cells

Berry

Mader

Lee

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

392

512

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Microbial communities are essential to the function of virtually all ecosystems and eukaryotes, including humans. However, it is still a major challenge to identify microbial cells active under natural conditions in complex systems. In this study, we developed a new method to identify and sort active microbes on the single-cell level in complex samples using stable isotope probing with heavy water (D 2 O) combined with Raman microspectroscopy. Incorporation of D 2 O-derived D into the biomass of autotrophic and heterotrophic bacteria and archaea could be unambiguously detected via C-D signature peaks in single-cell Raman spectra, and the obtained labeling pattern was confirmed by nanoscaleresolution secondary ion MS. In fast-growing Escherichia coli cells, label detection was already possible after 20 min. For functional analyses of microbial communities, the detection of D incorporation from D 2 O in individual microbial cells via Raman microspectroscopy can be directly combined with FISH for the identification of active microbes. Applying this approach to mouse cecal microbiota revealed that the host-compound foragers Akkermansia muciniphila and Bacteroides acidifaciens exhibited distinctive response patterns to amendments of mucin and sugars. By Ramanbased cell sorting of active (deuterated) cells with optical tweezers and subsequent multiple displacement amplification and DNA sequencing, novel cecal microbes stimulated by mucin and/ or glucosamine were identified, demonstrating the potential of the nondestructive D 2 O-Raman approach for targeted sorting of microbial cells with defined functional properties for singlecell genomics.ecophysiology | single-cell microbiology | carbohydrate utilization | nitrifier | Raman microspectroscopy M icroorganisms play a vital role in many environments. They mediate global biogeochemical cycles, catalyze biotechnological processes, and contribute to health and disease in the human body. The in situ study of microbial activity in natural and engineered ecosystems is therefore of great interest. For this purpose, several elegant methods have been established that use either transcriptional or translational activity of community members (i.e., metatranscriptomics, metaproteomics) (1-3) or the incorporation of isotopically labeled substrates into biomolecules (4-10) to infer the ecophysiology of microbes in such systems. However, these bulk techniques do not offer sufficient spatial resolution to study microbial activities at the micrometer scale. Therefore, important information can be overlooked because microbial communities are frequently spatially structured (e.g., biofilms) (11) and contain populations with life cycles (12,13). Furthermore, even apparently identical cells in clonal populations can have strongly divergent activities (14).Consequently, microbial ecophysiology is ideally studied also at the level of the single cell, but only a restricted number of approaches exist for determining physiological properties of individual cells in a microbial community. For exa...

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“…and liquid-crystalline phases. Although the band assignments, intensities, and frequency shifts have been previously reported and discussed (Levin, 1984;Bryant et al, 1982), a brief review of the salient vibrational parameters in these two spectral regions is necessary in order to discuss the molecular dynamics of the two lipids. In Figure 1A, three major Raman features are identified for the low-temperature gel phase of DHPC.…”

Section: Resultsmentioning

confidence: 99%

Raman spectroscopic studies of the packing properties of mixed dihexadecyl- and dipalmitoylphosphatidylcholine bilayer dispersions

Devlin¹,

Levin²

1989

Biochemistry

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X-ray diffraction studies suggest the existence of two separate gel phases for mixed dihexadecylphosphatidylcholine (DHPC)/dipalmitoylphosphatidylcholine (DPPC) bilayers [Kim, J. T., Mattai, J., & Shipley, G. G. (1987) Biochemistry 26, 6599-6603; Lohner, K., Schuster, A., Degovics, G., Müller, K., & Laggner, P. (1987) Chem. Phys. Lipids 44, 61-70]. In one gel phase the lipid chains are interdigitated, while the other gel phase exhibits the conventional bilayer form. We use Raman spectroscopy to provide a detailed molecular analysis of the intermolecular and intramolecular interactions of the DHPC and DPPC molecules within these mixed bilayers. Observation of the methylene chain C-H stretching modes of DHPC and the methylene chain C-D stretching modes of DPPC-d62 for various mixed DHPC/DPPC-d62 bilayers enables the packing characteristics and conformational order of each lipid to be monitored separately. The spectral data indicate that the packing properties of DPPC-d62 in the mixed-lipid bilayers remain relatively unchanged, while the intramolecular and intermolecular properties of DHPC change dramatically as a function of the composition of the DHPC/DPPC-d62 mixed bilayer. This is consistent with a model based upon the existence of three characteristic lipid types for the mixed-lipid system, namely, domains of pure DPPC-d62 and pure DHPC species with interface lipids or boundary regions between the bulk domains.

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Effects of membrane bilayer reorganizations on the 2103 cm⁻¹ Raman spectral CD stretching mode linewidths in dimyristoyl phosphatidylcholine‐d₅₄ (DMPC‐d₅₄) liposomes

Cited by 16 publications

References 21 publications

Direct Observation of Domains in Model Stratum Corneum Lipid Mixtures by Raman Microspectroscopy

Direct Observation of Domains in Model Stratum Corneum Lipid Mixtures by Raman Microspectroscopy

Tracking heavy water (D ₂ O) incorporation for identifying and sorting active microbial cells

Raman spectroscopic studies of the packing properties of mixed dihexadecyl- and dipalmitoylphosphatidylcholine bilayer dispersions

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Effects of membrane bilayer reorganizations on the 2103 cm−1 Raman spectral CD stretching mode linewidths in dimyristoyl phosphatidylcholine‐d54 (DMPC‐d54) liposomes

Cited by 16 publications

References 21 publications

Direct Observation of Domains in Model Stratum Corneum Lipid Mixtures by Raman Microspectroscopy

Direct Observation of Domains in Model Stratum Corneum Lipid Mixtures by Raman Microspectroscopy

Tracking heavy water (D 2 O) incorporation for identifying and sorting active microbial cells

Raman spectroscopic studies of the packing properties of mixed dihexadecyl- and dipalmitoylphosphatidylcholine bilayer dispersions

Contact Info

Product

Resources

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Effects of membrane bilayer reorganizations on the 2103 cm⁻¹ Raman spectral CD stretching mode linewidths in dimyristoyl phosphatidylcholine‐d₅₄ (DMPC‐d₅₄) liposomes

Tracking heavy water (D ₂ O) incorporation for identifying and sorting active microbial cells