Ribonucleic acid viruses

Viruses have no cell wall and made up of nucleic acid core enclosed in a protein coat which consists of identical subunits. Viruses are of two types, DNA (deoxyribonucleic acid) viruses and RNA (ribonucleic acid) viruses. DNA viruses are herpes simplex, small pox, hepatitis B, varicellazoster etc. and RNA viruses are rabies, measles, dengue, rubella, yellow fever, poliomyelitis and HIV etc. 

DNA was identified as the universal carrier of genetic information, with a few exceptions including RNA (ribonucleic acid) viruses. 

Keshgegian, A. A., and Glick, M. C., 1973, Glycoproteins associated with nuclei of cells before and after transformation by a ribonucleic acid virus. Biochemistry 12 1221. 

Extracts from 152 plant species, representing 46 different families, were screened for effects on tobacco mosaic virus (TMV) replication in cucumber cotyledons. Twenty species have shown enough activity to warrant further study. Several members of the Caprifoliaceae family increased virus replication. An extract of Lonicera involucrata enlarged the virus lesions in local lesion hosts and produced a thirty fold increase in virus titer, but had no effect on virus replication in systemic hosts. The active material appears to affect the virus defense mechanism of local lesion hosts. An extract of common geranium is an active virus inhibitor. It inactivates TMV and TMV-RNA (ribonucleic acid) in vitro by forming non-infectious complexes. In vivo, it also inhibited starch lesion formation in cucumber cotyledons incited by TMV infection. 

Deoxyribonucleic acid (DNA, Fig. 3-13) is the genetic material of all organisms, including plants, animals, and microorganisms. (Some viruses lack DNA, but use RNA (ribonucleic acid) in its place.) DNA carries all the hereditary information of the organism and is therefore replicated and passed from parent to offspring. RNA is formed on DNA in the nucleus of the... 

NAKANE H and ONO K (1990) Differential inhibitory effects of some catechin derivatives on the activities of human immunodeficiency virus reverse transcriptase and cellular deoyriboncleic and ribonucleic acid polymerases , Biochem, 29, 2841-5. 

Hepatitis A is a non-enveloped single-stranded ribonucleic acid (RNA) virus classified as the Hepatovirus genus under I the Picornaviridae family.1 The only host for the HAV is... 

The discovery of the base-paired, double-helical structure of deoxyribonucleic acid (DNA) provides the theoretic framework for determining how the information coded into DNA sequences is replicated and how these sequences direct the synthesis of ribonucleic acid (RNA) and proteins. Already clinical medicine has taken advantage of many of these discoveries, and the future promises much more. For example, the biochemistry of the nucleic acids is central to an understanding of virus-induced diseases, the immune re-sponse, the mechanism of action of drugs and antibiotics, and the spectrum of inherited diseases. 

Virases are much simpler organisms than bacteria, and they are made from protein substances and nucleic acid. A single nucleoprotein molecule formed from molecules of nucleic acid that are chemically bound to a bulky protein molecule can be considered a simple viral particle. The protein molecule plays the role of a protective membrane. Thus the virus can be schematically described as a nucleic acid insert that is protected by a protein covering. A virus can contain either ribonucleic acid or deoxyribonucleic acid, but it never contains both of them together. The type of nucleic acid is the basis of one of the classifications of viruses. Viruses are obligatory intracellular parasites, which, upon entering a cell (i.e. after being infected) use many biochemical systems of the host cell. 

Retrovirus—Virus whose genetic material is composed of ribonucleic acid (RNA). 

Let us consider the structure of the tobacco mosaic virus first. As shown schematically in Figure 5.1, it is composed of a single strand of ribonucleic acid, RNA, covered by a sheath formed from 2130 identical protein units. Thus the whole virus constitutes a rather simple supramolecular assembly. By changing... 

Richards, S., Pedersen, B., Silverton, J. V., and Hoard, J. L. Stereochemistry of ethylene-diaminetetraacetato complexes. Inorg. Chem. 3, 27-33 (1964). s°) Boedtker, H. Configurational properties of tobacco mosaic virus ribonucleic acid. J. Mol. Biol. 2, 171-188(1960). 

Small ribonucleic acid (RNA) containing viruses. For example, polio viruses, which destroy the anterior horn cells leading to lower motor neuron paralysis, are of this type. 

The term nucleoside was originally proposed by Levene and Jacobs in 1909 for the carbohydrate derivatives of purines (and, later, of pyrimidines) isolated from the alkaline hydrolyzates of yeast nucleic acid. The phosphate esters of nucleosides are the nucleotides, which, in polymerized forms, constitute the nucleic acids of all cells.2 The sugar moieties of nucleosides derived from the nucleic acids have been shown, thus far, to be either D-ribose or 2-deoxy-D-eri/fAro-pentose ( 2-deoxy-D-ribose ). The ribo-nucleosides are constituents of ribonucleic acids, which occur mainly in the cell cytoplasm whereas 2-deoxyribo -nucleosides are components of deoxypentonucleic acids, which are localized in the cell nucleus.3 The nucleic acids are not limited (in occurrence) to cellular components. They have also been found to be important constituents of plant and animal viruses. 

Deoxyribonucleic acid is the only nucleic acid found in T-even phage,88 and earlier reports89 of the presence of ribonucleic acid in bacterial virus T2 and T6 in small, variable proportions are now attributed88 to a contamina-... 

An organism s genome is the complete set of genetic instructions, passed from one generation to the next. The genome consists of a set of instructions for building each of the components of a living cell or virus. The information is found in nucleic acids usually deoxyribonucleic acid (DNA), but sometimes ribonucleic acid (RNA). 

TK Tn-368 Tn 7 tPA tRNA UTR X-gal YACs virus thymidine kinase cell line originated from the ovary of the insect Trichoplmia ni transposon 7 tissue plasminogen activator transfer ribonucleic acid untranslated regions 5-bromo-4-chloro-3-indolyl- -D-galactoside yeast artificial chromosomes... 

DNA RNA iRNA AAV HSV deoxyribonucleic acid ribonucleic acid interference RNA adeno-associated virus herpes simplex virus... 

Kawade, Y. Physicochemical study of ribonucleic acid. Ann. Rept. Inst. Virus Res., Kyoto Univ. 2, 219—268 (1959). 

A virus is a submicroscopic agent of infectious disease that requires a living cell for its multiplication. The two essential components of a virus are protein and nucleic acid. Whereas normal cells contain both RNA (ribonucleic acid) and DNA (deoxyribonucleic acid), a given virus contains only one, not both. A virus cannot multiply on its own as a normal cell does. It has no metabolic enzymes, uses no nutrients, and produces no energy. It is just a particle of protein and nucleic acid. A viral particle is tightly packed inside a protein coat that protects it. This unit is called a virion. 

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