Escherichia coli Membrane Fluidity as Detected by Excimerization of Dipyrenylpropane: Sensitivity to the Bacterial Fatty Acid Profile

Mejía, Ricardo; Gómez-Eichelmann, M C; Fernández, Marta

doi:10.1006/abbi.1999.1275

Cited by 21 publications

(13 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An increase in growth temperature is known to increase the degree of saturation of membrane fatty acids in microorganisms. 34,35 When R eutropha H850 was grown on fructose at 37°C, the membrane fatty acid pro®le resembled that of cells grown on biphenyl at 28°C (Table 1), which is again consistent with previous work. 22 In contrast, a decrease in growth temperature of R eutropha H850 to 17°C resulted in an increase in unsaturated fatty acids (Table 1).…”

Section: Total Fatty Acid Compositionssupporting

confidence: 86%

Alterations in fatty acid composition and fluidity of cell membranes affect the accumulation of PCB congener 2,2′,5,5′‐tetrachlorobiphenyl by Ralstonia eutropha H850

Kim

Beaudette

Cassidy

et al. 2002

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

The effect of alterations in fatty acid composition and¯uidity of cell membranes on the accumulation of PCB congener 2,2',5,5'-tetrachlorobiphenyl (TeCB) by Ralstonia eutropha (formerly Alcaligenes eutrophus) H850 was studied. Cells of R eutropha H850 grown on either biphenyl or fructose were used. Signi®cant increases in saturated fatty acid composition and decreases in membrane¯uidity of bacteria grown on biphenyl at 28°C were observed compared with those grown on fructose at 17 or 28°C. The ratio of saturated fatty acids to unsaturated fatty acids and membranē uidity of R eutropha H850 grown on biphenyl at 28°C resembled those of cells grown on fructose at 37°C. No inhibition effect of the uncoupler 2,4-dinitrophenol (2,4-DNP) on TeCB accumulation was observed, suggesting an energy-independent mechanism for TeCB accumulation in cells of R eutropha H850. The amount of TeCB accumulated was considerably higher in R eutropha H850 grown on fructose at 17 and 28°C than when grown on biphenyl at 28°C. Similar amounts of TeCB accumulated in bacteria grown on biphenyl at 28°C as compared with those grown on fructose at 37°C. These results suggest the alterations in fatty acid composition and membrane¯uidity of R eutropha H850 may affect the accumulation of TeCB.

show abstract

Section: Total Fatty Acid Compositionssupporting

confidence: 86%

Alterations in fatty acid composition and fluidity of cell membranes affect the accumulation of PCB congener 2,2′,5,5′‐tetrachlorobiphenyl by Ralstonia eutropha H850

Kim

Beaudette

Cassidy

et al. 2002

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

show abstract

“…It is important to note that small changes (of about 10%) in fluorescence anisotropy may reflect pronounced changes (of about 25%) in membrane microviscosity (19). The results obtained with DPH show a 9 to 21% increase in the anisotropy values (P Յ 0.001) in the opaque variants compared with the trans- It was shown in Escherichia coli that changes in cell surface physical properties, such as phase transition temperature and membrane microviscosity, show a positive linear correlation with the proportion of unsaturated fatty acids in the bacterial lipids (14). In this study, the lipid acyl chain profile of four opaque-transparent S. pneumoniae strains shows that the two variants carry the same types of fatty acyl residues, mainly saturated and unsaturated straight C 16 and C 18 acids, as reported before for other strains of S. pneumoniae (24).…”

Section: Discussionmentioning

confidence: 90%

Differences in Membrane Fluidity and Fatty Acid Composition between Phenotypic Variants of Streptococcus pneumoniae

Aricha

Fishov

Cohen³

et al. 2004

J Bacteriol

View full text Add to dashboard Cite

Phase variation in the colonial opacity of Streptococcus pneumoniae has been implicated as a factor in the pathogenesis of pneumococcal disease. This study examined the relationship between membrane characteristics and colony morphology in a few selected opaque-transparent couples of S. pneumoniae strains carrying different capsular types. Membrane fluidity was determined on the basis of intermolecular excimerization of pyrene and fluorescence polarization of 1,6-diphenyl 1,3,5-hexatriene (DPH). A significant decrease, 16 to 26% (P < 0.05), in the excimerization rate constant of the opaque variants compared with that of the transparent variants was observed, indicating higher microviscosity of the membrane of bacterial cells in the opaque variants. Liposomes prepared from phospholipids of the opaque phenotype showed an even greater decrease, 27 to 38% (P < 0.05), in the pyrene excimerization rate constant compared with that of liposomes prepared from phospholipids of bacteria with the transparent phenotype. These findings agree with the results obtained with DPH fluorescence anisotropy, which showed a 9 to 21% increase (P < 0.001) in the opaque variants compared with the transparent variants. Membrane fatty acid composition, determined by gas chromatography, revealed that the two variants carry the same types of fatty acids but in different proportions. The trend of modification points to the presence of a lower degree of unsaturated fatty acids in the opaque variants compared with their transparent counterparts. The data presented here show a distinct correlation between phase variation and membrane fluidity in S. pneumoniae. The changes in membrane fluidity most probably stem from the observed differences in fatty acid composition.Phase variation in the colonial opacity of Streptococcus pneumoniae has been implicated as a factor in the pathogenesis of pneumococcal disease (27). The different appearance of bacterial colonies is assumed to result from the spontaneous and reversible phase variation of surface components, the identity of which is not yet clear. The frequency of switching is highly variable from isolate to isolate, ranging from 10 Ϫ3 to 10 Ϫ6 per generation. The significance of opacity variation in the biology of pneumococcal infection in vivo was examined by using animal models of nasopharyngeal colonization and bacteremia. Transparent variants persist in the nasopharynx in vivo and show greater adherence to human lung epithelial cells. However, experiments performed with an adult mouse model of sepsis showed a strong selection for organisms with the opaque morphology during invasive infections (28).Genetic experiments were used to isolate a single locus able to confer altered colony opacity at a higher frequency than the background rate (18). The opacity locus was found to be associated with two genes in the presumed glycerol operon, glpF and glpD, required for glycerol metabolism in other bacteria. This finding raises the possibility that phase variation in S. pneumoniae is linked to the mechani...

show abstract

“…1,3-dipyrenylpropane (DPP) incorporation into membranes forms intramolecular excimers depending mainly on the medium microviscosity and temperature of determination [99]. Membrane fluidity is determined by estimating the excimer to monomer fluorescence intensity ratio (Ie/Im) of this fluorescent probe, a quotient that reflexes the lateral mobility of membrane phospholipids [100].…”

Section: Methodsmentioning

confidence: 99%

Accumulation of Exogenous Amyloid-BetaPeptide in Hippocampal Mitochondria Causes Their Dysfunction: A Protective Role for Melatonin

Rosales-Corral

Acuña-Castroviejo²,

Tan

et al. 2012

Oxidative Medicine and Cellular Longevity

View full text Add to dashboard Cite

Amyloid-beta (Aβ) pathology is related to mitochondrial dysfunction accompanied by energy reduction and an elevated production of reactive oxygen species (ROS). Monomers and oligomers of Aβ have been found inside mitochondria where they accumulate in a time-dependent manner as demonstrated in transgenic mice and in Alzheimer's disease (AD) brain. We hypothesize that the internalization of extracellular Aβ aggregates is the major cause of mitochondrial damage and here we report that following the injection of fibrillar Aβ into the hippocampus, there is severe axonal damage which is accompanied by the entrance of Aβ into the cell. Thereafter, Aβ appears in mitochondria where it is linked to alterations in the ionic gradient across the inner mitochondrial membrane. This effect is accompanied by disruption of subcellular structure, oxidative stress, and a significant reduction in both the respiratory control ratio and in the hydrolytic activity of ATPase. Orally administrated melatonin reduced oxidative stress, improved the mitochondrial respiratory control ratio, and ameliorated the energy imbalance.

show abstract

Escherichia coli Membrane Fluidity as Detected by Excimerization of Dipyrenylpropane: Sensitivity to the Bacterial Fatty Acid Profile

Cited by 21 publications

References 25 publications

Alterations in fatty acid composition and fluidity of cell membranes affect the accumulation of PCB congener 2,2′,5,5′‐tetrachlorobiphenyl by Ralstonia eutropha H850

Alterations in fatty acid composition and fluidity of cell membranes affect the accumulation of PCB congener 2,2′,5,5′‐tetrachlorobiphenyl by Ralstonia eutropha H850

Differences in Membrane Fluidity and Fatty Acid Composition between Phenotypic Variants of Streptococcus pneumoniae

Accumulation of Exogenous Amyloid-BetaPeptide in Hippocampal Mitochondria Causes Their Dysfunction: A Protective Role for Melatonin

Contact Info

Product

Resources

About