Direct Visualization of Gram-Negative Bacterial Lipopolysaccharide Self-Assembly

Aurell, Christina; Hawley, M. E.; Wistrom, Anders O.

doi:10.1006/mcbr.1999.0149

Cited by 19 publications

(17 citation statements)

References 22 publications

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“…Theoretical equations [16,17] can be used to estimate R g and R h values (and, therefore, 1) if geometry and dimensions are known. However, the geometry and axial dimensions published by Aurell et al [15] lead to estimates that are not in agreement with our experimental results. However, comparison of the two studies is hampered by the fact that different LPS types and temperatures were used.…”

Section: Discussioncontrasting

confidence: 99%

“…The diameters obtained by dynamic light scattering spectroscopy for the LPS aggregates from E. coli serotype 026:B6 at 37 8C are higher than the values obtained for other LPS types at room temperature with the same technique [14,15] as well as by microscopy imaging methods. [13,15] The data presented in Figure 4 indicates that well above the CMC a , the increase of LPS concentration results in more aggregates, without any change in their dimensions.…”

Section: Discussionmentioning

confidence: 92%

“…However, comparison of the two studies is hampered by the fact that different LPS types and temperatures were used. Moreover, no indication of the aggregation state of the sample (namely, below or above the CMC a ) is provided by Aurell et al [15] . There is a possible correlation between our findings and the LPS concentration-dependent physiological functional effects, which could be explained by a better accessibility of recognition structures to CD14 and/or LBP (LPS-binding proteins required for cell activation) in the smaller premicelle oligomers.…”

Section: Discussionmentioning

confidence: 98%

“…[13,15] The data presented in Figure 4 indicates that well above the CMC a , the increase of LPS concentration results in more aggregates, without any change in their dimensions. The apparent transition range and the hyperbolic-like distribution of the data points arise from the coexistence of two supramolecular species, which leads to an apparent intermediate diameter and to asymptotic behavior ( Figure 4) as a result of a balance of the light scattering contributions from the premicelle oligomers and from the larger aggregates in the calculations of the average diffusion coefficient (and thus, the average diameter).…”

Section: Discussionmentioning

confidence: 99%

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Evaluation of Lipopolysaccharide Aggregation by Light Scattering Spectroscopy

et al. 2003

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Lipopolysaccharides (LPS) are cell wall components of Gram-negative bacteria. These molecules behave as bacterial endotoxins and their release into the bloodstream is a determinant of the development of a wide range of pathologies. These amphipathic molecules can self-aggregate into supramolecular structures with different shapes and sizes. The formation of these structures occurs when the LPS concentration is higher than the apparent critical micelle concentration (CMC(a)). Light scattering spectroscopy (both static and dynamic) was used to directly characterize the aggregation process of LPS from Escherichia coli serotype 026:B6. The results point to a CMC(a) value of 14 microg mL(-1) and the existence of premicelle LPS oligomers below this concentration. Both structures were characterized in terms of molecular weight (5.5 x 10(6) and 16 x 10(6) g mol(-1) below and above the CMC(a), respectively), interaction with the aqueous environment, gyration radius (56 and 105 nm), hydrodynamic radius, (60 and 95 nm) and geometry of the supramolecular structures (nearly spherical). Our data indicates that future in vitro experiments should be carried out both below and above the CMC(a). The search for drugs that interact with the aggregates, and thus change the CMC(a) and condition LPS interactions in the bloodstream, could be a new way to prevent certain bacterial-endotoxin-related pathologies.

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Section: Discussioncontrasting

confidence: 99%

Section: Discussionmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

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Evaluation of Lipopolysaccharide Aggregation by Light Scattering Spectroscopy

et al. 2003

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“…Santos et al proposed that the critical concentrations for the transitions between monomer and premicelle (preaggregate) oligomer and between premicelle oligomer and large aggregate are defined as CMC (critical micelle concentration) and CMCa (apparent CMC), respectively [3]. Aurell et al found that even at very low concentrations (e.g., 10 pg/ml), lipopolysaccharides may be highly aggregated into doublet structures without any visible signs of the LPSs breaking up into individual LPS monomers [4]. The aggregation of lipopolysaccharides also depends on the conformation and hydrophobicity of the contributing glycoform-specific LPS.…”

mentioning

confidence: 99%