Inactivation of Reovirus Type 2 by a Combination of Chloroform and Moderate Temperature

The infectivity and hemagglutinins of reovirus type 2 were destroyed at 37 C in the presence of chloroform, whereas no effect of chloroform was noted at 0 C.     

Hemagglutinins of some Aspergilli

Hemagglutinins for human red blood cells have been found in hot-water soluble mycelial extracts of a strain of Aspergillus flavus and two mutant strains of A. parasiticus. The agglutinin from one strain of A. parasiticus was specific for blood group A cells while the other two agglutinins were non-specific. With the A. flavus strain, the greatest hemagglutination activity (HA) was found at 10 days for the mycelial extract, and at 12 days for culture fluid preparations. More agglutinin was produced by fungi grown on sucrose than on d-glucose as carbon source. Solubilities in ammonium sulfate solutions and protein and carbohydrate analyses show that the agglutinins from the mycelial extract and culture fluid preparation are different. The mycelial agglutinin was inhibited by a number of different sugars, many of which possess common stereochemical features.     

Hemagglutinins extracted from locks of unopened cotton bolls

Hemagglutinins, which may mediate plant-fungal interactions, were detected in water soluble extracts from locks of unopened cotton bolls. Hemagglutinating activity was nondialyzable, and thus the agglutinating components possess molecular weights greater than 6 000 daltons. Five of 23 tested sugars inhibited agglutination. The inhibitory sugars did not possess common stereochemical features and included mono-, di-, and trisaccharides.     

Hemagglutinins and fimbriae of Providencia spp.

A series of 25 strains of Providencia spp. produced at least five different patterns of hemagglutination as judged by results from hemagglutination tests in the presence and absence of D-mannose and at least six distinct types of fimbriae as seen from observations with the electron microscope.     

Defective Virions of Reovirus

When purified preparations of stock reovirus, type 3, were digested with chymotrypsin, the virions were converted into two different types of particle. These new particles could be separated from each other by isopycnic centrifugation in cesium chloride gradients. One particle banded at a buoyant density of 1.43 g/cm(3), the other at a density of 1.415 g/cm(3). The former particle is termed the heavy (H) particle, the latter is the light (L) particle. The ratio of H/L particles varied between 0.5 and 0.25 in various purified preparations of virus. In electron micrographs, both H and L particles had the appearance and dimensions of viral cores. H particles were infectious for L cells. When plaques formed by stock virus, or by H particles, were picked and propagated in L cells, the majority of the clones gave rise only to H particles on chymotrypsin digestion. On continued serial passage of the clones, virions containing L particles again appeared in the progeny. The simplest explanation of these results was that stock virus was comprised of two populations of virions. One type of virion which contained H particles was infectious, whereas the other, which contained L particles, was not itself infectious and could replicate only in cells coinfected with an H particle virion. Added weight was given to this hypothesis by two observations. First, a small but definite separation of H and L virions could be achieved by isopycnic centrifugation in a gradient of cesium chloride. Second, L particles and virions containing L particles were both shown to lack the largest of the ten segments of double-stranded ribonucleic acid genome. Thus, L particle virions have defective genomes.