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The dissolution and formation of egg phosphatidylcholine (PC) vesicles by the detergent octyl glucoside were examined systematically by using resonance energy transfer between fluorescent lipid probes, turbidity, and gel filtration chromatography. Resonance energy transfer was exquisitely sensitive to the intermolecular distance when the lipids were in the(More)
Fusion of vesicular stomatitis virus (VSV) with Vero cells was measured after exposure of the virus to low pH under a variety of experimental conditions. The method of relief of fluorescence self-quenching of the probe octadecylrhodamine was used to monitor fusion. Incubation of the virus at pH 5.5 prior to binding to cells led to significant enhancement of(More)
Polylysine induced aggregation and fusion of negatively charged small unilamellar phosphatidylcholine vesicles containing at least 10% anionic lipid. Aggregation was followed by absorbance changes and fusion was assayed both by electron microscopy and by fluorescence energy transfer between lipid probes. A method for preparing asymmetric vesicles, where the(More)
The composition of mixed micelles of egg phosphatidylcholine (PC) and octyl glucoside was studied by a novel technique based on measuring resonance energy-transfer efficiency between two fluorescent lipid probes present in trace amounts. Equations were derived for calculating the stoichiometry of the composition of mixed micelles from the energy-transfer(More)
We have investigated the binding ability to DNA of compounds belonging to the 2-azaanthraquinone-type structure and have examined the effect on the activity of DNA gyrase as well as on mammalian topoisomerases in vitro. Using different biophysical techniques it was found that one of these ligands, 9-((2-dimethylamino)ethyl)amino)-6-hydroxy-7-methoxy-5,(More)
The ability of an HPLC gel exclusion column (TSK G6000PW) to separate lipid vesicles, viruses, and biological vesicles according to size was tested and compared with separations on Sephacryl S1000. The columns were calibrated using vesicular Stokes radii determined by quasielastic light scattering. The vesicles separated according to size on both types of(More)
Protein K is an outer membrane protein found in pathogenic encapsulated strains of Escherichia coli. We present evidence here that protein K is structurally and functionally related to the E. coli K-12 porin proteins (OmpF, OmpC, and PhoE). Protein K was found to cross-react with antibody to OmpF protein and to share 8 out of 17 peptides in common with the(More)
The circular dichroism spectra of Hg(II) complexes with native calf thymus DNA, chemically methylated Streptomyces chrysomallus DNA and with Ag(I)-DNA complexes were measured in the region of 220 - 340 nm. As a main result a conversion of the conservative CD spectrum of DNA to a distinct nonconservative type of CD spectrum for the complexes occurs with(More)
The assay of DNA unwinding by ethidium, followed by sedimentation velocity techniques, was applied to complexes of supercoiled plasmid DNA with different non-intercalating drugs which strongly and sequence-specifically bind to DNA. Compared with the behaviour of naked DNA, most of the complexes exhibit an increase in the critical EB/nucleotide binding ratio(More)
Two viruses, respiratory syncytial virus (RSV) and vesicular stomatitis virus (VSV) were used to evaluate viral purification by an affinity resin column (Matrex Cellufine Sulfate (MCS); Amicon Division, WR Grace & Co.). Viable RSV was purified significantly from crude cell lysate by a single pass through a column containing the anionic MCS resin. Most cell(More)