15 research outputs found
Host Cell Receptor Binding by Baculovirus GP64 and Kinetics of Virion Entry
AbstractGP64 is the major envelope glycoprotein from budded virions of the baculoviruses Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) and Orgyia pseudotsugata multicapsid nucleopolyhedrovirus (OpMNPV). To examine the potential role of GP64 as a viral attachment protein in host cell receptor binding, we generated, overexpressed, and characterized a soluble form of the OpMNPV GP64 protein, GP64solOp. Assays for trimerization, sensitivity to proteinase K, and reduction by dithiothreitol suggested that GP64solOp was indistinguishable from the ectodomain of the wild-type OpMNPV GP64 protein. Virion binding to host cells was analyzed by incubating virions with cells at 4°C in the presence or absence of competitors, using a single-cell infectivity assay to measure virion binding. Purified soluble GP64 (GP64solOp) competed with a recombinant AcMNPV marker virus for binding to host cells, similar to control competition with psoralen-inactivated wild-type AcMNPV and OpMNPV virions. A nonspecific competitor protein did not similarly inhibit virion binding. Thus specific competition by GP64solOp for virion binding suggests that the GP64 protein is a host cell receptor-binding protein. We also examined the kinetics of virion internalization into endosomes and virion release from endosomes by acid-triggered membrane fusion. Using a protease sensitivity assay to measure internalization of bound virions, we found that virions entered Spodoptera frugiperda Sf9 cells between 10 and 20 min after binding, with a half-time of approximately 12.5 min. We used the lysosomotropic reagent ammonium chloride to examine the kinetics of membrane fusion and nucleocapsid release from endosomes after membrane fusion. Ammonium chloride inhibition assays indicated that AcMNPV nucleocapsids were released from endosomes between 15 and 30 min after binding, with a half-time of approximately 25 min
Spin oscillations in transient diffusion of a spin pulse in n-type semiconductor quantum wells
By studying the time and spatial evolution of a pulse of the spin
polarization in -type semiconductor quantum wells, we highlight the
importance of the off-diagonal spin coherence in spin diffusion and transport.
Spin oscillations and spin polarization reverse along the the direction of spin
diffusion in the absence of the applied magnetic field are predicted from our
investigation.Comment: 5 pages, 4 figures, accepted for publication in PR
Efficient Generation of Functional Epithelial and Epidermal Cells from Human Pluripotent Stem Cells Under Defined Conditions
Multiple mating, sperm transfer and oviposition pattern in the giant sperm species, Drosophila bifurca
Embryonic development of mushroom bodies in Pterostichus niger schall. (Coleoptera: Carabidae)
The energy bands of quantized spin waves and the uniaxial anisotropy in a biferromagnetic system
The eigenproblems of quantized spin waves in a (100)
ferromagnetic bilayer system have been investigated theoretically using the
interface rescaling approach. The energy-band structure of the system has
been obtained and the effect of the uniaxial bulk anisotropy field of
easy-axis type on the energy bands are explored thoroughly. It is found that
all kinds of eigenmodes of the spin waves in the biferromagnetic system are
determined by the bulk exchange coupling constant, the interface exchange
coupling constant, the spin of lattice, the number of atomic layers and the
uniaxial bulk anisotropy. Especially, we explore the effect of the uniaxial
bulk anisotropy field of easy-axis type on the energy bands of first
Brillouin zone and the existence condition of all kinds of the eigenmodes