Conformational Changes and Association of Membrane-Interacting Peptides in Myelin Membrane Models: A Case of the C-Terminal Peptide of Proteolipid Protein and the Antimicrobial Peptide Melittin.

Model membranes composed of various lipid mixtures can segregate into liquid-ordered (Lo) and liquid-disordered (Ld) phases. In this study, lipid vesicles composed of mainly Lo or Ld phases as well as complex lipid systems representing the cytosolic leaflet of the myelin membrane were characterized by fluorescence resonance energy transfer with a donor/acceptor pair that preferentially partitioned into Lo or Ld phases, respectively. The fluidity of the lipid systems containing >30% cholesterol was modulated in the presence of the amphipathic peptide melittin.

Dynamic turn conformation of a short tryptophan-rich cationic antimicrobial peptide and its interaction with phospholipid membranes.

Cationic antimicrobial peptides are promising sources for novel therapeutic agents against multi-drug-resistant bacteria. HHC-36 (KRWWKWWRR) is a simple but effective antimicrobial peptide with similar or superior activity compared with several conventional antibiotics. In this biophysical study, unique conformational properties of this peptide and some of its analogs as well as its interaction with lipid membranes are investigated in detail.

Partitioning of myelin basic protein into membrane microdomains in a spontaneously demyelinating mouse model for multiple sclerosis.

We have characterized the lipid rafts in myelin from a spontaneously demyelinating mouse line (ND4), and from control mice (CD1 background), as a function of age and severity of disease. Myelin was isolated from the brains of CD1 and ND4 mice at various ages, and cold lysed with 1.5% CHAPS (3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulphonate).

White matter rafting--membrane microdomains in myelin.

The myelin membrane comprises a plethora of regions that are compositionally, ultrastructurally, and functionally distinct. Biochemical dissection of oligodendrocytes, Schwann cells, and central and peripheral nervous system myelin by means such as cold-detergent extraction and differential fractionation has led to the identification of a variety of detergent-resistant membrane assemblies, some of which represent putative signalling platforms. We review here the different microdomains that have hitherto been identified in the myelin membrane, particularly lipid rafts, caveolae, and cellular junctions such as the tight junctions that are found in the radial component of the CNS myelin sheath.

N-hydroxyarylamine O-acetyltransferase-deficient Escherichia coli strains are resistant to the mutagenicity of nitro compounds.

In Salmonella typhimurium, a single enzyme catalyzes both the acetyl CoA-dependent O-acetylation of hydroxylamines (a key step in the activation of mutagenic nitroaromatic compounds and related aromatic and heterocyclic amines) and the N-acetylation of aromatic amines. S. typhimurium Ames test mutants lacking this activity are highly resistant to the genotoxic effects of nitro compounds.

Perspectives on the chemical etiology of breast cancer.

Multiple factors, known and unknown, contribute to human breast cancer. Hereditary, hormonal, and reproductive factors are associated with risk of breast cancer. Environmental agents, including chemical carcinogens, are modifiable risk factors to which over 70% of breast cancers have been attributed.