Purification of viral RNA by means of bentonite.

Publisher Summary This chapter highlights how the current understanding of the mechanisms and factors influencing virus adsorption can be used to interpret and control virus behavior in the environment. An understanding of factors controlling the interaction has already led to new and improved methods for the concentration of viruses from water, and their isolation from the environment. It is evident that not all viruses behave alike toward a solid under identical conditions. Under most natural conditions viruses with a low isoelectric point appear to be more poorly adsorbed to most solid surfaces. This must be taken into consideration when evaluating concentration or treatment systems which involve adsorption. This phenomenon is also important in determining the transport of viruses in the environment. Certain enteric viruses appear to adsorb less readily to soils and aquatic sediments than others. Thus their potential transport to groundwater may be greater and they may be less likely to settle in surface waters. To take into consideration these differences in virus behavior, it is perhaps best to use viruses with widely varying isoelectric points or marked differences in hydrophobicity to evaluate the extremes in virus interaction with a given surface which could occur.

Applied and Theoretical Aspects of Virus Adsorption to Surfaces

1. Ribosomal RNA has been prepared by extracting tissues with a phenol-cresol mixture, and ribosomal RNA can be selectively precipitated with m-cresol. No rapidly labelled RNA was associated with this material. 2. However, if RNA and DNA are extracted with 4-aminosalicylate and phenol-cresol mixture and the nucleic acids precipitated, DNA, glycogen and s-RNA (transfer RNA) can be extracted with 3m-sodium acetate and in this case rapidly labelled RNA remains associated with the ribosomal RNA. 3. The ribosomal RNA is stable in the presence of concentrated salt solution and, although the secondary structure is lost by heating at 70 degrees in 10mm-sodium acetate, it can be re-formed in the presence of 200mm-sodium acetate. 4. The 28s and 18s components have been separated and their base compositions determined.

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Isolation and characterization of ribosomal ribonucleic acid

Publisher Summary This chapter discusses the studies relating to the chemical nature of alkylation, from the products of nucleoside alkylation to in vivo effects of alkylating agents that are oncogenic. The reactions of simple methylating agents with nucleosides, nucleotides, and polynucleotides have also been discussed in the chapter. More recent studies of the mechanism of alkylation by nitroso compounds and ethylating agents have shown that both qualitatively and quantitatively the site of alkylation is a function of both the type of reagent used and the conformation and milieu of the nucleic acid. However, translation of this body of knowledge to an understanding of the biological mechanism of alkylation-induced mutagenesis and carcinogenesis is difficult. Further studies of mutation in picornaviruses or their RNAs would be fruitful since these viral RNAs are also messenger RNAs and are directly translated, whereas in vivo studies, definitive information is still lacking as to whether alkylation of DNA, RNA, or perhaps protein, is the biologically important event.

The chemical effects of nucleic acid alkylation and their relation to mutagenesis and carcinogenesis.

Oxidative processes are often harnessed as tools for pathogen disinfection. Although the pathways responsible for bacterial inactivation with various biocides are fairly well understood, virus inactivation mechanisms are often contradictory or equivocal. In this study, we provide a quantitative analysis of the total damage incurred by a model virus (bacteriophage MS2) upon inactivation induced by five common virucidal agents (heat, UV, hypochlorous acid, singlet oxygen, and chlorine dioxide). Each treatment targets one or more virus functions to achieve inactivation: UV, singlet oxygen, and hypochlorous acid treatments generally render the genome nonreplicable, whereas chlorine dioxide and heat inhibit host-cell recognition/binding. Using a combination of quantitative analytical tools, we identified unique patterns of molecular level modifications in the virus proteins or genome that lead to the inhibition of these functions and eventually inactivation. UV and chlorine treatments, for example, cause site-specific capsid protein backbone cleavage that inhibits viral genome injection into the host cell. Combined, these results will aid in developing better methods for combating waterborne and foodborne viral pathogens and further our understanding of the adaptive changes viruses undergo in response to natural and anthropogenic stressors.

B. Singer

Papers

Purification of viral RNA by means of bentonite.

Reconstitution of tobacco mosaic virus. iv. inhibition by enzymes and other proteins, and use of polynucleotides.

Effects of bentonite on infectivity and stability of TMV-RNA☆

Protein synthesis in virus-infected plants. I. The number and nature of TMV-directed proteins detected on polyacrylamide gels.

Possible identification of a protein in brome mosaic virus infected barley as a component of viral RNA polymerase