Suspensions Of Tobacco Mosaic Virus Research Articles

Evolution of Stimulated Inelastic Scattering Spectra of Laser Radiation in Tobacco Mosaic Virus Suspension

Evolution of Stimulated Inelastic Scattering Spectra of Laser Radiation in Tobacco Mosaic Virus Suspension

Low-frequency laser spectroscopy of cylindrical nanoparticle suspensions

A theory of generation of anti-Stokes radiation on the eigenvibrations in a suspension of cylindrical nanoparticles in the field of two copropagating electromagnetic pump waves has been developed. Surface ponderomotive forces are shown to induce acoustic vibrations and dipolemoments of nanoparticles at the anti-Stokes frequency. Under these conditions, the scattering efficiency depends on the dielectric characteristics of the solution and the acoustic parameters of the liquid and solid fractions of the suspension. Experiments on stimulated low-frequency Raman scattering of laser radiation in aqueous suspensions of tobacco mosaic virus in a buffer solution have been performed. A coherent signal of the Stokes component with a frequency shift of ≈60GHz is detected; this value is in good agreement with the estimated frequency shift for stimulated excitation of eigenvibrations of cylindrical nanoparticles in a liquid: ≈50 GHz.

Stimulated low-frequency Raman scattering in a suspension of tobacco mosaic virus

The interaction of laser pulses with tobacco mosaic virus (TMV) in Tris-HCl pH7.5 buffer and in water has been investigated. Ruby laser pulses of 20 ns duration have been used for excitation. The spectrum of the light passing through the sample was registered with the help of a Fabry–Perot interferometer. In the case of TMV in water we observed in the spectrum only one line of the exciting laser light, but for TMV in Tris-HCl pH7.5 buffer a second line appeared, corresponding to stimulated low-frequency Raman scattering (SLFRS) on the breathing radial mode of TMV. The frequency shift of the SLFRS by 2 cm−1 (60 GHz), the conversion efficiency and the threshold are measured for the first time to the best of our knowledge.

Dependence on sphere size of the phase behavior of mixtures of rods and spheres

By the addition of chondroitin sulfate (Chs) to the aqueous suspension of tobacco mosaic virus (TMV), the aggregation of TMV occurs at very dilute TMV concentration compared with the addition of polyethylene oxide (PEO). The difference of physical behavior between Chs and PEO is the chain conformation in solution. The Chs chain has a semirigid nature, whereas the PEO chain has a flexible nature. In this study, the Chs and PEO chains are simplified to spherical particles having different size, and we use the spherocylinder model for TMV particle. The effect of the sphere size on the phase behaviors in the mixtures of rods and spheres is investigated by Monte Carlo simulations. By the addition of small spheres, the system transforms from the miscible isotropic phase to the miscible nematic phase. On the other hand, by the addition of large spheres, the system changes from the miscible isotropic phase to the immiscible nematic phase through the immiscible isotropic phase. The different phase behaviors between the small and the large spheres originate from the difference of overlapping volume of the depletion zone. In addition, we perform the Monte Carlo simulations in the case that semirigid chains are used as the Chs chain models. The same phase behaviors are observed as the mixtures of rods and large spheres. Thus the sphere model captures the phase behaviors of rod and polymer mixture systems.

The Effect of Sphere Size on the Phase Behaviors in the Rod and Sphere Mixture System

The addition of polysaccharides, such as chondroitin sulfate (Chs), to the aqueous suspension of tobacco mosaic virus (TMV) results in the TMV aggregation at very dilute TMV concentration compared with the addition of polyethylene oxide (PEO). The Chs chain has a semirigid nature, whereas the PEO has a flexible nature. In this study, we investigated the effect of the size of spherical polymer coils on the phase behaviors in the mixtures of rods and spheres using Monte Carlo simulations. As a model for TMV, we used the spherocylinder particle. The Chs and PEO chains were simplified to spherical particles having different sizes. With the addition of large spherical particles, the system changed from miscible phase to isotropic–isotropic phase separation and then isotropic–nematic phase separation states, whereas with the addition of small spherical particles, the system transformed from miscible isotropic phase to miscible nematic phase. We found that the sphere size had an important influence on the phase behaviors in the mixtures of rods and spheres.

Virus-induced permeability transition in mitochondria

Isolated rat liver mitochondria undergo permeability transition after supplementation with a suspension of tobacco mosaic virus. Four mitochondrial parameters proved the opening of the permeability transition pore in the inner mitochondrial membrane: increased oxygen consumption, collapse of the membrane potential, release of calcium ions from mitochondria, and high amplitude mitochondrial swelling. All virus-induced changes in mitochondria were prevented by cyclosporin A. These effects were not observed if the virus was treated with EGTA or disrupted by heating. Protein component of the virus particle in the form of 20S aggregate A-protein, or helical polymer, as well as supernatant of the heat-disrupted virus sample, had no effect on mitochondrial functioning. Electron microscopy revealed the direct interaction of the virus particles with isolated mitochondria. The possible role of the mitochondrial permeability transition pore in virus-induced apoptosis is discussed.

Measurement of Residual Dipolar Couplings of Macromolecules Aligned in the Nematic Phase of a Colloidal Suspension of Rod-Shaped Viruses

Measurement of Residual Dipolar Couplings of Macromolecules Aligned in the Nematic Phase of a Colloidal Suspension of Rod-Shaped Viruses

Antiviral activity of chondroitin sulfate against infection by tobacco mosaic virus

In the course of searching for antiviral substances against the tobacco mosaic virus (TMV), it was found that chondroitin sulfate (Chs) A-type and C-type had a high inhibitory activity against TMV infection. The addition of Chs to the inoculum solution greatly reduced the number of local lesions formed on Xanthi NN tobacco leaves. The degree of inhibition increased with Chs concentration and was higher in C-type than A-type, which suggests that the strength of inhibition relates to the stiffness of the polymer chain of Chs. For Chs C-type inhibition was independent of molecular weight where the molecular weight was between 30000 and 70000, and decreased with molecular weight below 30000. The electron micrograph showed that the TMV suspension itself was almost monodisperse and that the addition of Chs caused TMV to form large raftlike aggregates. The TMV solution became turbid after the addition of a large amount of Chs. The antiviral activity of Chs on the infectivity of TMV may be caused by blocking the decapsulation process of TMV protein on the cell membrane surface.

Angular correlations and the isotropic-nematic phase transition in suspensions of tobacco mosaic virus.

The specific magnetic-field-induced birefringence is measured in aqueous suspensions composed of the charged rodlike particle tobacco mosaic virus (TMV) as a function of temperature, TMV concentration, ionic strength, and TMV polydispersity over the entire isotropic range. This quantity is proportional to the magnitude of the interparticle angular correlations at zero field. Theoretical expressions for the field-induced birefringence for both the mono- and polydisperse samples are derived based on extensions of the Onsager model [L. Onsager, Ann. N.Y. Acad. Sci. 51, 627 (1949)] and compare well with experiment. In addition, the isotropic-nematic phase coexistence concentrations are measured as a function of ionic strength and temperature. The agreement between experiment and theory indicates that the TMV particles interact primarily through electrostatic repulsion and that attractive forces are negligible.

Isotropic-nematic phase transition and angular correlations in isotropic suspensions of tobacco mosaic virus.

The specific magnetic-field-induced birefringence is measured in isotropic suspensions of the rodlike particle tobacco mosaic virus as a function of concentration and added salt. This quantity is proportional to the angular correlations between particles at zero field. In addition, the isotropic-nematic coexistence concentrations are measured as a function of ionic strength. The data compare well with a scaled functional theory assuming decoupling between the angular and spatial degrees of freedom.

Magnetic birefringence study of isotropic suspensions of tobacco mosaic virus

The magnetic field induced birefringence in isotropic aqueous suspensions of tobacco mosaic virus (TMV) was measured as a function of temperature and concentration in high magnetic fields (100 kG). The temperature range was between 15 and 50 °C and the concentration range was between 4 and 20 mg/cm3. We find that the Cotton–Mouton constant (C) increases with decreasing temperature by 15%–20% over the entire range and extrapolates to infinity at a finite temperature of 110 to 150 K. At constant temperature, the measured ρ/C(ρ=number of TMV particles per cm3 of suspension) can be expanded in a power series of ρ, where the coefficients are expressed by the irreducible cluster integrals. At 20 °C the experimental values can be fitted to the linear form: ρ/λC=(2.09×1030–1.35×1015ρ)G2/cm3. For rigid cylindrical particles with l=3000 Å and d=180 Å, and using the rigid hard particle interaction model, we find for the first order coefficient 0.62×1015, i.e., a significant deviation for the rigid hard-rod model. This deviation is also indicated by the variation of C with temperature. We discuss the results on TMV and of similar measurements on phage fd in terms of the interparticle interaction and rigidity of the particles.

A Study of the Effects of Microwave Energy on Plant Viruses

Several studies have been performed indicating that microwave energy causes genetic damage. The question of how microwaves cause this damage has not yet been definitively proven. It has recently been shown that isolated DNA can resonantly absorb microwaves, and that damage results from the vibrations of the DNA. However, it has not been shown that this occurs in organized biological systems. In order to explore the question of resonance in an organized system, suspensions of Tobacco Mosaic Virus and Wheat Streak Mosaic Virus were exposed to varying amounts of microwave energy. It was found that both TMV and WSMV are inactivated after exposure to microwave energy. Further experimentation revealed that interrupted exposure times which prevented the suspensions from becoming heated did not produce an effect. However, when exposure times were long enough to heat the suspensions, the viruses were inactivated indicating that damage to these viruses was thermally induced.

Measurements of the anisotropic viscous and elastic properties of lyotropic polymer nematics

We summarize the current status of our studies of the macroscopic linear mechanical properties of nematic liquid crystals formed from solutions of rigid or semirigid rod-like polymers. The polymer system we have studied is a racemic mixture of poly(benzyl glutamate) dissolved in a mixture of dioxane and methylene chloride. We have also studied nematics formed from colloidal suspensions of tobacco mosaic virus which may be viewed as an ideal model system representing a rigid-rod polymer solution. We review briefly the current theoretical understanding of the elastic and viscous parameters characterizing a nematic. Then we discuss our experiments, both Frederiks-transition studies and quasielastic Rayleigh scattering. The Frederiks transition in its well known simple forms is not easily utilized in these systems, mainly because of the intervention of a number of phenomena not normally encountered in low-molecular-weight liquid crystals. However, these phenomena have been analysed theoretically and can be used to extract information on elastic and viscous properties. Quasielastic Rayleigh scattering on well oriented single crystals has proved to be an excellent technique for measuring ratios of elastic and viscous parameters. We describe the scattering geometries we have used and our results.

Spectrum of light quasi-elastically scattered from suspensions of tobacco mosaic virus. Experimental study of anisotropy in translational diffusion

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSpectrum of light quasi-elastically scattered from suspensions of tobacco mosaic virus. Experimental study of anisotropy in translational diffusionKenji Kubota, Hisako Urabe, and Yasunori TominagaCite this: Macromolecules 1984, 17, 10, 2096–2104Publication Date (Print):October 1, 1984Publication History Published online1 May 2002Published inissue 1 October 1984https://doi.org/10.1021/ma00140a038RIGHTS & PERMISSIONSArticle Views177Altmetric-Citations65LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

The specific infectivity of tobacco mosaic virus

Comparative studies are made between the dip method of inoculation, by which Nicotiana glutinosa L. leaves are rub-injured prior to immersion into a tobacco mosaic virus (TMV) suspension, and the usual rub method of inoculation, by which a TMV suspension is rubbed directly on a leaf. Inactivation of TMV with antiserum is considerably more efficient when measured by the dip method than by the rub method. A study of the ultraviolet inactivation of a TMV-antiserum mixture suggests that TMV-antibody aggregates are left intact and are infectious by the dip method whereas the aggregates are dispersed into single infectious particles by the rub method. A decrease in infectivity with antiserum, as measured by the rub method, is attributed only to specific inactivation of TMV with antibody. A decrease in infectivity, as measured by the dip method, is a function of both the degree of aggregation, controlled by varying the molecular (A:G) ratio of antibody to virus, and the specific inactivation of TMV with antibody. A correlation between the decrease in infectivity and the size of the aggregates at specific A:G ratios suggests that, at the least, one out of ten TMV particles in a purified preparation is infectious.

Protein-Protein Interactions

Publisher Summary This chapter focuses on protein–protein interaction. The unique characteristics of different proteins are developed in the interactions of proteins with each other, with ions, and with nonprotein materials such as lipids, nucleic acids, and carbohydrates. These range from covalent bonds and electrostatic interactions to the weaker electronic van der Waals' attractive forces characteristic of all atoms and groups of atoms. The interactions of proteins with each other in an aqueous environment may be divided into two categories: (1) those which take place at such distances that the average properties of the protein or its surface may be used in calculating interaction energies, and (2) those in which the interacting molecules approach closely and thus bring into play local forces, the total of which depends to a major extension specific groups and group configurations. Interactions at distances may be further subdivided into those interactions, which lead to a concentration dependence of osmotic pressure, sedimentation coefficient, and those long-range interactions which lead to more complex phenomena such as the separation of phases in suspensions of tobacco mosaic virus and bentonite. An interaction is observed only when the protein molecule is subject to a structural change which brings bonding groups into positions which allow them to interact. Structural changes of this type may be reversible or irreversible. Certain ephemeral interactions, particularly enzymatic reactions, generally lead to chemical or physical changes in one of the interactants to a much greater extent than the other.

Effects of X-ray radiation upon the pathogenicity and antigenicity of tobacco mosaic virus

The present work was undertaken in order to investigate the effects of X-ray radiation upon the pathogenicity and antigenicity of tobacco mosaic virus (TMV).The virus preparation used in this work was the aqueous suspension of TMV purified by Bawden's procedure. The antiserum was prepared by injecting rabbits with the purified TMV. The infectivity of the irradiated virus was tested by the half-leaf method using Nicotiana glutinosa as assay plants. In serological tests of TMV, the precipitin reaction was used. The virus preparation 2 or 3mm thick in a Petri dish of 5cm in diameter was irradiated at 5cm distance from an anticathode of an X-ray tube run at 60KVP and or 10mA. The mean wave-length of X-ray used in this work was 0.4A, and dosages measured were 2400r/min. in the case of 15mA and 1600r/min. in that of 10mA. The pH of the virus preparations were 6.0∼6.2 and their temperatures were 14°∼20°C during the irradiations, and as the X-ray tube employed was water-cooled no rising of temperature of the preparations due to the irradiations was recognized.The results of experiments are summarized as follows:(1) The non-infective preparations of TMV which had been inactivated by X-ray radiation always showed to be serologically active, and it was moreover found that the serological activities of irradiated preparations increased within the limits of dosage used in the experiments, on the contrary of decreasing of the infectivity (Tables 1 and 2).(2) The logarithm of the surviving fraction has been plotted against the dosage of irradiation according to the results of the virus activity assay (half-leaf mnethod), and the survival curve was shown by a straight line (Fig. 1 and 2). Consequently, these results seem to agree with the view that the inactivation of virus by ionizing radiation is caused by a single ionization or a single cluster of ionization, as the inactivation follows a simple exponential curve.(3) The inactivation doses (the 37% doses) were estimated from the above-mentioned curves, to be approximately 28×104r in the case of preparations of 0.2% and 2×104r in the occasion of 0.02%.