RNA viruses and

In contrast to retroviruses, proteolysis is an early event in the replication cycle of (+)-strand RNA viruses and both protease and polymerase inhibitors can be expected to halt the propagation of infectious viral particles from already infected cells. 

Methisazone (Fig. 5.2IB) inhibits DNA viruses (particularly vaccinia and variola) but not RNA viruses, and has been used in the prophylaxis of smallpox. It is now little used, especially as, according to the World Health Organization, smallpox has now been eradicated. 

Li+ is currently administered topically for the relief of HSV and, in addition, it has been demonstrated that the recurrence of HSV infection is inhibited in Li+-treated patients, indicating another potential prophylactic effect of Li+ [245]. Ointment containing 8% lithium succinate has been shown to reduce the severity and the incidence of recurrent genital HSV infection in man [246]. It has also been proposed that Li+ might be efficacious in treating HIV-infected patients, although any benefits have not yet been demonstrated [247]. While HTV is a RNA virus and as such might not be predicted to be affected by Li+, it is a retrovirus and utilizes a DNA intermediate for its replication and it uses a DNA polymerase. 

Green, M., Gerard, G.F. RNA-directed DNA polymerase properties and functions in oncogenic RNA viruses and cells. In Progress in nucleic acid res. and molec. biol. Vol. 

Helical tobamaviruses, enveloped single positive-sense strand RNA viruses and, 158... 

M], negative-strand RNA viruses and, 161 M2, negative-strand RNA viruses and,161-162... 

Negative-strand RNA viruses, 158-163 ebola virus matrix protein/ glycoprotein, 162-163 hemagglutinin-neuraminidase and, 162 influenza A and, 158-163 Ml and, 161 Ms and, 161-162 neuraminidase and, 161 paramyxovirus fusion protein and, 162 Neuraminidase, negative-strand RNA viruses and, 161... 

Paramyxovirus fusion protein, negative-strand RNA viruses and, 162 Pariacoto virus, 223 Particle reconstruction images, 198 Parvoviridae family, 238-240 Desovirinae subfamily of 239 Parvovirinae subfamily of 239 of single-stranded DNA (ssDNA) viruses, 242... 

Recently, another genome, GBV C (ca. 9,200 nucleotides), was identified by means of PCR. (539, 549) It is defined as a single-stranded (+) RNA virus and forms a separate species within the flaviviridae family. It seems that the original serum of GB contained no (or no more) GBV A, GBV B or GBV C RNA thus the above mentioned surgeon s hepatitis remains unclarified with regard to the causative virus type. In the meantime HCV could be differentiated into five subtypes la, lb, 2a, 2b and 3a. 

The sensitivity of DNA to alkylation receives support from a wide variety of experiments which have shown, among other things, that DNA viruses are more susceptible than RNA viruses and that DNA synthesis in many cell lines is inhibited at dose levels that have no effect on RNA or protein synthesis. 

The influenza virus is an RNA-(—)- virus and possesses its own RNA polymerase enzyme. The complete RNA genome codes for eight proteins - two structural (matrix) proteins M, and M2, haemagglutinin, and neuraminidase and four proteins involved in replication, three of which make up the polymerase enzyme. Substrates for this are the usual ribonucleosides and there has been some success with the use of nucleoside analogues as inhibitors of the enzyme. The drug ribavirin has been the most successful, although this has to be administered by aerosol. These days, its major use is for the treatment of infections caused by respiratory syncytial viruses (especially in children), since these can cause long-term morbidity. 

As with influenza, the brevity of the incubation period and the fact that by the time the first symptoms appear, the virus will already be present in large amounts, means that prophylaxis and treatment are difficult. Add to this the fact that the cold may be due to another type of virus, for example, an adenovirus (a DNA virus) or a respiratory syncitial virus, and the problems appear insuperable. And indeed, at present, no drugs have reached the marketplace. The rhinoviruses are RNA-(+)-viruses and have two principal viral enzymes an RNA polymerase and a protease, but although a number of potential enzyme inhibitory drugs have been evaluated in clinical trials, none has reached the marketplace. 

We report here the use of BART in diagnosis of Chlamydia trachomatis from human urine specimens, detection of an RNA virus and screening test for GM contamination in maize. BART is a way forward for molecular in vitro diagnostics with great potential for bringing it into any setting including small laboratories, point-of-care or even into the field. 

Ribavirin is a synthetic guanosine analogue, with in vitro activity against a broad spectrum of DNA and RNA viruses, and retroviruses, including HIV. Ribavirin has been used for treatment of a variety of viral infections, including respiratory syncytial virus bronchiolitis and pneumonia, measles, influenza types A and B, Lassa fever, hemorrhagic fever with renal syndrome (Hantaviruses), hepatitis C, and HIV infection. It is used commonly now along with interferon alpha for treatment of hepatitis C infection. There is no known direct nephrotoxicity of ribavirin. 

Viruses are small parasites that can replicate only In host cells. Viral genomes may be either DNA (DNA viruses) or RNA (RNA viruses) and either single- or double-stranded. 

Chromones and Coumarins Anwii species (Umbettiferae) Corfandrum sativum DNA, RNA viruses and Bacteriophages HIV Cross linking viral DNA Adds to viral pyrimidines (in DNA) and uridines (in RNA), forming cycloadduct [11] [21]... 

They are all RNA viruses, and all are covered, or enveloped, in a fatly (lipid) coating. 

Lassa fever is an acute viral illness that occurs in West Africa. The illness was discovered in 1969 when two missionary nurses died in Nigeria, West Africa. The cause of the illness was found to be Lassa vims, named after the town in Nigeria where the first cases originated. The virus, a member of the virus family Arenaviridae, is a single-stranded RNA virus and is zoonotic, or aniiiial-bome. 

The activity of this group of compounds is usually confined to RNA viruses, and guanidine itself has long been known as a specific inhibitor of the synthesis of viral RNA polymerase [225]. Once the polymerase has been formed then guanidine has no effect on its activity [226]. 

Advanced virology. RNA viruses and retrotransposons predated the formation of DNA vimses in the pre-cellular virus world of Koonin et al [18]. Precellular ribosome-like entities might have been operated by ribozymes and RNPs. Cellular ribosomes could remain operational extracellularly (Heinrich Matthaei and Marshall Nirenberg, vide infra). In the cellular world, there are two enzymes that transcribe RNA to DNA telomerase and reverse transcriptase (RT). The gene of the enzyme RT is a component of the retroviral genome [32]. Template-encoded proteins of this complexity are not expected to have been formed in the pre-cellular era, unless precellular RNP-armed entities resembling ribosomes existed. 

Weber F, Wagner V, Rasmussen SB et al. Double-stranded RNA is produced by positive-strand RNA viruses and DNA viruses but not in detectable amounts by negative-strand RNA viruses. J Virol 2006 80(10) 5059-5064. 

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