Antiviral activity of polysaccharides against infection of tobacco mosaic virus

Abstract

In the course of searching for antiviral substances to tobacco mosaic virus (TMV), it was found that polysaccharides have a high inhibitory activity against TMV infection. The leaves of Xanthi NN tobacco were rubbed with the mixtures of TMV and polysaccharides such as chondroitin sulfate C‐ and A‐ types. The addition of polysaccharides to the inoculum solution greatly reduced the number of local lesions formed on the inoculated leaves. Here the polysaccharide did not completely prevent virus entry into the leaves and the virus particles may penetrate and multiply in leaves without forming lesions. Although the electron micrograph showed that the virus suspension was almost monodisperse, the addition of polysaccharides caused TMV to form large raft‐like aggregates. The TMV solution became turbid after the addition of a large amount of polysaccharides. A threshold concentration of polysaccharides exists for virus precipitation, which is independent of the virus concentration. The size of polysaccharide at the threshold concentration agreed well with that obtained by light scattering method. The strength of the interaction between TMV and polysaccharides was found to be related to the degree of inhibitory activity of polysaccharides.

Orientation-dependent depletion interaction in rodlike colloid-polymer mixtures

“…Since both the phase boundaries of an isotropic and a nematic phase are shifted to lower rod concentrations with increasing φ P , the nematic-isotropic phase separation can be induced at very low rod concentrations. Such phenomena have been experimentally suggested in mixtures of tobacco mosaic virus and chondroitin sulphate [20]. We also find that the concentration region, in which the nematic phase is stable, becomes broad on increasing the polymer concentration.…”

“…Mixtures of a rodlike colloid and a polymer show a variety of phase separations such as isotropic-nematic [14][15][16][17][18][19][20][21][22][23] and nematic-smectic phase transitions [24,25]. For example, the nematic-isotropic phase separation has been investigated in suspensions of tobacco mosaic virus by adding polymers such as polyethylene oxide [19].…”

The isotropic–nematic transition and the phase separation of the tobacco mosaic virus particles with polysaccharide

“…These results are in agreement with the experimental result that at very low concentration of TMV particles, the isotropic-nematic transition of TMV particles does not depend on the concentration of TMV particles. 3 We also investigated the effect of system size. In Fig.…”

“…In their system, the flocculation of the TMV particles is observed when the concentration of TMV and PEO are about 10-150 and about 1-10 mg/ml, respectively. On the other hand, in the case of TMV and Chs mixture, 3,4 the aggregation of TMV is observed when the concentrations of TMV and Chs are about 0.03-0.1 and about 1.3-4.0 mg/ ml, respectively. Thus Chs induces the isotropic-nematic transition of the TMV particles in a very low concentration region.…”

“…1,2 Recently, it was found that tobacco mosaic virus ͑TMV͒ infection is inhibited in the presence of polysaccharides such as chondroitin sulfate ͑Chs͒. 3,4 The TMV particle is a plant virus having a rigid rod shape of 15-18 nm diameter and 300 nm length. In the absence of Chs, the TMV particles are dispersed isotropically in water as shown in a transmission electron micrograph of Fig.…”