Preparation and potentialin vivoanti-influenza virus activity of low molecular-weight κ-carrageenans and their derivatives

2012 ◽  
Vol 127 (3) ◽  
pp. 2110-2115 ◽  
Author(s):  
Fengxiang Tang ◽  
Fang Chen ◽  
Feng Li
Keyword(s):  
Molecular Weight ◽  
Influenza Virus ◽  
Low Molecular Weight ◽  
Virus Activity

Ca2+-sensitive permeability changes caused by influenza virus

1983 ◽  
Vol 3 (8) ◽  
pp. 749-755 ◽  
Author(s):  
Kalpana Patel ◽  
Charles A. Pasternak
Keyword(s):  
Molecular Weight ◽  
Influenza Virus ◽  
Plasma Membrane ◽  
Trypan Blue ◽  
Low Molecular Weight ◽  
Permeability Change ◽  
Permeability Changes ◽  
Phosphorylated Compounds

Influenza virus added to Lettré cells at pH 5.3 induces a permeability change similar to that elicited by Sendal virus at pH 7.4: K+ and Na+ equilibrate across the plasma membrane and low-molecular-weight phosphorylated compounds leak out of cells, which remain impermeable to trypan blue.

scholarly journals Cleavage of Influenza A Virus Hemagglutinin in Human Respiratory Epithelium Is Cell Associated and Sensitive to Exogenous Antiproteases

2002 ◽  
Vol 76 (17) ◽  
pp. 8682-8689 ◽  
Author(s):  
Oleg P. Zhirnov ◽  
Mine R. Ikizler ◽  
Peter F. Wright
Keyword(s):  
Molecular Weight ◽  
Influenza Virus ◽  
Serine Proteases ◽  
Influenza A ◽  
Extracellular Fluid ◽  
Respiratory Epithelium ◽  
Influenza Viruses ◽  
Secretory Cells ◽  
Low Molecular Weight ◽  
Virus Growth

ABSTRACT Proteolytic cleavage of the hemagglutinin (HA) of human influenza viruses A/Aichi/2/68 (H3N2) and A/WSN/34 (H1N1) from HA0 to HA1/HA2 was studied in primary human adenoid epithelial cells (HAEC). HAEC contain a mixture of ciliated and nonciliated secretory cells and mimic the epithelium membrane of the human respiratory tract. Pulse-chase labeling with [35S]methionine and Western blot analysis with anti-HA antibodies of cellular and virion polypeptides showed that HAEC cleaved newly synthesized HA0 to HA1/HA2 (“cleavage from within”) and significant amounts of cleaved HA accumulated within cells. It was also shown that HAEC was able to cleave HA0 of incoming virions (“cleavage from without”), whereas the HA0 of nonabsorbed virions free in extracellular fluid were not cleaved, supporting the conclusion that HA0 cleavage in HAEC is cell associated. Low-molecular-weight inhibitors of serine proteases, aprotinin and leupeptin, when added to influenza virus-infected HAEC suppressed HA0 cleavage and reduced the amount of cleaved HA1/HA2 both in cells and in progeny virions and thus diminished the infectivity of the virus. In contrast, the addition of fetal bovine serum, containing a number of high-molecular-weight antiproteases that compete for proteases in the extracellular environment, did not inhibit influenza virus growth in HAEC. These data suggest that in human respiratory epithelium the cleavage of influenza virus HA containing a single arginine in the proteolytic site (i) is a cell-associated process accomplished by serine-type protease(s) and (ii) is sensitive to low-molecular-weight exogenous inhibitors of serine proteases.

scholarly journals THE SIZE OF INFLUENZA VIRUS

1944 ◽  
Vol 79 (3) ◽  
pp. 267-283 ◽  
Author(s):  
W. M. Stanley
Keyword(s):  
Molecular Weight ◽  
Influenza Virus ◽  
High Molecular Weight ◽  
Particle Diameter ◽  
Allantoic Fluid ◽  
Sucrose Density Gradient ◽  
Chick Embryos ◽  
Sedimentation Behavior ◽  
Virus Activity ◽  
Sedimentation Constant

The sedimentation behavior of influenza virus in dilute solutions of electrolyte was found to be quite variable. At times the virus activity appeared to sediment at a rate comparable with that of particles about 80 to 120 mµ in diameter, at other times at a rate comparable with that of particles about 10 mµ in diameter, and at still other times the bulk of the activity appeared to sediment at a rate comparable with that of the larger particles and the residual activity at a rate comparable with that of the smaller particles. However, in the presence of a sucrose density gradient, the virus activity was always found to sediment with a rate comparable to that of particles about 80 to 120 mµ in diameter; hence it appeared that the variable sedimentation behavior in dilute electrolyte solution was due to convection or mechanical disturbances during centrifugation. About 30 per cent of the high molecular weight protein present in the allantoic fluid of chick embryos infected with the F 12 strain of influenza virus was found to consist of a component having a sedimentation constant of about 30 S, and hence a probable particle diameter of about 10 mµ. The residual protein of high molecular weight was present in the form of a component having a sedimentation constant of about 600 S, and hence a probable particle diameter of about 70 mµ. The proportion of the 30 S component in allantoic fluid of chick embryos infected with the PR8 strain of influenza virus was found to be considerably less. The 600 S and 30 S components of F 12 allantoic fluid were purified and separated by differential centrifugation. The purified preparations of the 600 S component were found to possess a specific virus activity from 100 to over 10,000 times that of the purified preparations of the 30 S component, the difference in activity apparently depending only on the degree of fractionation of the two components. The purified 30 S component was found to sediment normally in the presence of 12 per cent sucrose, whereas the small residual virus activity of such preparations was found to sediment in the presence of a sucrose density gradient with a rate comparable to that of much heavier particles. It is concluded that influenza virus activity is not associated with material having a particle diameter of about 10 mµ, but is associated solely with material having a sedimentation constant of about 600 S and hence a probable particle diameter of about 70 mµ.

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

Low-molecular-weight heparin in the prevention and treatment of thromboembolic disorders

1998 ◽  
Vol 1 (5) ◽  
pp. 166-174 ◽  
Author(s):  
Evelyn R Hermes De Santis ◽  
Betsy S Laumeister ◽  
Vidhu Bansal ◽  
Vandana Kataria ◽  
Preeti Loomba ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Low Molecular Weight ◽  
Prevention And Treatment
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