scholarly journals Dependence of norfloxacin diffusion across bilayers on lipid composition

Soft Matter ◽  
2016 ◽  
Vol 12 (7) ◽  
pp. 2135-2144 ◽  
Author(s):  
Sowmya Purushothaman ◽  
Jehangir Cama ◽  
Ulrich F. Keyser
Keyword(s):  
Antibiotic Resistance ◽  
Lipid Composition ◽  
Lipid Membranes ◽  
Relative Concentration ◽  
Bacterial Membranes

Antibiotic resistance is a major concern in medicine, and a better understanding of the interactions of antibiotics with the lipid molecules found in bacterial membranes is therefore highly desirable. We study the permeation of the antibiotic norfloxacin across vesicle lipid membranes of variable lipid compositions, and show that norfloxacin permeation is dependent on both the type and relative concentration of lipid molecules in the membrane.

scholarly journals The lipid composition of a barley mutant lacking chlorophyll b

1978 ◽  
Vol 174 (1) ◽  
pp. 67-72 ◽  
Author(s):  
P Bolton ◽  
J Wharfe ◽  
J L Harwood
Keyword(s):  
Linolenic Acid ◽  
Lipid Composition ◽  
Acid Content ◽  
Relative Concentration ◽  
Enoic Acid ◽  
Chlorophyll B ◽  
Alpha Linolenic Acid ◽  
Barley Mutant ◽  
Acyl Lipid ◽  
Acyl Lipids

The acyl-lipid composition of a barley mutant that contained no detectable chlorophyll b was studied. This mutant contained chloroplasts that were much less organized than chloroplasts of normal barley. The mutant contained all the normal acyl lipids, with small increases in the relative concentration of phosphatidylglycerol and diacylsulphoquinoglycerides was unchanged, but most other lipids of the mutant barley contained lower amounts of alpha-linolenic acid compared with normal. There was no difference in the transhexadec-3-enoic acid content of phosphatidylglycerol, which was evidence against this lipid being involved in grana stacking.

scholarly journals Correlation of Bacterial Lipid Composition with Antibiotic Resistance

1970 ◽  
Vol 101 (3) ◽  
pp. 892-900 ◽  
Author(s):  
June K. Dunnick ◽  
William M. O'Leary
Keyword(s):  
Antibiotic Resistance ◽  
Lipid Composition ◽  
Bacterial Lipid

scholarly journals Composition-function analysis of HDL subpopulations: influence of lipid composition on particle functionality

2020 ◽  
Vol 61 (3) ◽  
pp. 306-315 ◽  
Author(s):  
Katrin Niisuke ◽  
Zsuzsanna Kuklenyik ◽  
Katalin V. Horvath ◽  
Michael S. Gardner ◽  
Christopher A. Toth ◽  
...  
Keyword(s):  
Lipid Composition ◽  
Cholesterol Efflux ◽  
Neutral Lipids ◽  
Function Analysis ◽  
Binding Capacity ◽  
Relative Concentration ◽  
Lipid Binding ◽  
Total Lipids ◽  
Function Relationship ◽  
Relationship Of

The composition-function relationship of HDL particles and its effects on the mechanisms driving coronary heart disease (CHD) is poorly understood. We tested the hypothesis that the functionality of HDL particles is significantly influenced by their lipid composition. Using a novel 3D-separation method, we isolated five different-sized HDL subpopulations from CHD patients who had low preβ-1 functionality (low-F) (ABCA1-dependent cholesterol-efflux normalized for preβ-1 concentration) and controls who had either low-F or high preβ-1 functionality (high-F). Molecular numbers of apoA-I, apoA-II, and eight major lipid classes were determined in each subpopulation by LC-MS. The average number of lipid molecules decreased from 422 in the large spherical α-1 particles to 57 in the small discoid preβ-1 particles. With decreasing particle size, the relative concentration of free cholesterol (FC) decreased in α-mobility but not in preβ-1 particles. Preβ-1 particles contained more lipids than predicted; 30% of which were neutral lipids (cholesteryl ester and triglyceride), indicating that these particles were mainly remodeled from larger particles not newly synthesized. There were significant correlations between HDL-particle functionality and the concentrations of several lipids. Unexpectedly, the phospholipid:FC ratio was significantly correlated with large-HDL-particle functionality but not with preβ-1 functionality. There was significant positive correlation between particle functionality and total lipids in high-F controls, indicating that the lipid-binding capacity of apoA-I plays a major role in the cholesterol efflux capacity of HDL particles. Functionality and lipid composition of HDL particles are significantly correlated and probably both are influenced by the lipid-binding capacity of apoA-I.

scholarly journals Shaping the lipid composition of bacterial membranes for membrane protein production

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Kerstin Kanonenberg ◽  
Jorge Royes ◽  
Alexej Kedrov ◽  
Gereon Poschmann ◽  
Federica Angius ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Lipid Composition ◽  
Protein Production ◽  
Bacterial Membranes

Effect of cell lipid composition on the formation of nonspecific antibiotic resistance in alkanotrophic rhodococci

Microbiology ◽  
2000 ◽  
Vol 69 (1) ◽  
pp. 51-57 ◽  
Author(s):  
M. S. Kuyukina ◽  
I. B. Ivshina ◽  
M. I. Rychkova ◽  
O. B. Chumakov
Keyword(s):  
Antibiotic Resistance ◽  
Lipid Composition ◽  
Cell Lipid

scholarly journals Characterization and Antimicrobial Activity of Amphiphilic Peptide AP3 and Derivative Sequences

Antibiotics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 20 ◽  
Author(s):  
Christina Chrom ◽  
Lindsay Renn ◽  
Gregory Caputo
Keyword(s):  
Antimicrobial Activity ◽  
Fluorescence Spectroscopy ◽  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Cd Spectroscopy ◽  
Membrane Permeabilization ◽  
Bacterial Membrane ◽  
Bacterial Strains ◽  
Bacterial Membranes ◽  
Model Lipid Membranes

The continued emergence of new antibiotic resistant bacterial strains has resulted in great interest in the development of new antimicrobial treatments. Antimicrobial peptides (AMPs) are one of many potential classes of molecules to help meet this emerging need. AMPs are naturally derived sequences, which act as part of the innate immune system of organisms ranging from insects through humans. We investigated the antimicrobial peptide AP3, which is originally isolated from the winter flounder Pleuronectes americanus. This peptide is of specific interest because it does not exhibit the canonical facially amphiphilic orientation of side chains when in a helical orientation. Different analogs of AP3 were synthesized in which length, charge identity, and Trp position were varied to investigate the sequence-structure and activity relationship. We performed biophysical and microbiological characterization using fluorescence spectroscopy, CD spectroscopy, vesicle leakage assays, bacterial membrane permeabilization assays, and minimal inhibitory concentration (MIC) assays. Fluorescence spectroscopy showed that the peptides bind to lipid bilayers to similar extents, while CD spectra show the peptides adopt helical conformations. All five peptides tested in this study exhibited binding to model lipid membranes, while the truncated peptides showed no measurable antimicrobial activity. The most active peptide proved to be the parent peptide AP3 with the highest degree of leakage and bacterial membrane permeabilization. Moreover, it was found that the ability to permeabilize model and bacterial membranes correlated most closely with the ability to predict antimicrobial activity.

Effects of lipid composition on partitioning of fullerene between water and lipid membranes

2013 ◽  
Vol 68 (2) ◽  
pp. 290-295 ◽  
Author(s):  
Yeonjeong Ha ◽  
Howard M. Liljestrand ◽  
Lynn E. Katz
Keyword(s):  
Chain Length ◽  
Lipid Composition ◽  
Lipid Membranes ◽  
Partition Coefficients ◽  
Acyl Chain ◽  
Critical Factor ◽  
Acyl Chain Length ◽  
Unsaturated Lipids ◽  
Increasing Temperature ◽  
Supported Lipid Membranes

Fullerene partition coefficients (Klipw) between water and solid supported lipid membranes were determined for membranes of various lipid types and composition over a range of temperatures. The log Klipw (L/kg) values for fullerene, which range from 3.1 to 5.3, depend on the lipid type in the lipid membranes. Partition coefficients increased with increasing temperature, increasing acyl chain length of unsaturated lipids. The results indicate that lipid composition is a critical factor for bioconcentration of fullerene.

scholarly journals Rational tuning of a membrane-perforating antimicrobial peptide to selectively target membranes of different lipid composition

2020 ◽  
Author(s):  
Charles H. Chen ◽  
Charles G. Starr ◽  
Shantanu Guha ◽  
William C. Wimley ◽  
Martin B. Ulmschneider ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
High Throughput ◽  
Lipid Composition ◽  
Lipid Membranes ◽  
Md Simulations ◽  
Sequence Structure ◽  
Pore Former ◽  
Minor Sequence ◽  
Large Repertoire ◽  
Simple Sequence

AbstractThe use of designed antimicrobial peptides as drugs has been impeded by the absence of simple sequence-structure-function relationships and design rules. The likely cause is that many of these peptides permeabilize membranes via highly disordered, heterogeneous mechanisms, forming aggregates without well-defined tertiary or secondary structure. We demonstrate that the combination of high-throughput library screening with atomistic computer simulations can successfully address this challenge by tuning a previously developed general pore forming peptide into a selective pore former for different lipid types. A library of 2,916 peptides was designed based on the LDKA template. The library peptides were synthesized and screened using a high-throughput orthogonal vesicle leakage assay. Dyes of different sizes were entrapped inside vesicles with varying lipid composition to simultaneously screen for both pore size and affinity for negatively charged and neutral lipid membranes. From this screen, nine different LDKA variants that have unique activity were selected, sequenced, synthesized, and characterized. Despite the minor sequence changes, each of these peptides has unique functional properties, forming either small or large pores and being selective for either neutral or anionic lipid bilayers. Long-scale, unbiased atomistic molecular dynamics (MD) simulations directly reveal that rather than rigid, well-defined pores, these peptides can form a large repertoire of functional dynamic and heterogeneous aggregates, strongly affected by single mutations. Predicting the propensity to aggregate and assemble in a given environment from sequence alone holds the key to functional prediction of membrane permeabilization.

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