| T O P I C R E V I E W |
| cfish |
Posted - 08/07/2007 : 18:32:18
hi all just wondered if any one out there can let me know what measles virus RNA is as this was found in our sons lungs it also said they couldnt tell if it was the wild type or vaccine strain ,we cant get them retested untill the inquest is over thanks ,sarah n chris |
| 6 L A T E S T R E P L I E S (Newest First) |
| cfish |
Posted - 08/13/2007 : 20:40:47
yes its all very complex,we have now made an appointment with child doctor at our local hospital so he can explain all this and the rest of the reports we have thanks again gus .chris |
| GUS THE FUSS |
Posted - 08/12/2007 : 22:31:27
Last from me Chris so complex..
http://www.hhmi.org/cgi-bin/askascientist/highlight.pl?kw=&file=answers%2Fmolecular%2Fans_013.html
Submitted by Luo, an undergraduate student from China
Is all RNA coded by DNA? How does RNA mutate, and how do the mutations cause diseases?
Provided by A.C. Rodriguez, postdoctoral researcher, Center for Neurologic Diseases, Brigham and Woman's Hospital, Boston (former HHMI predoctoral fellow)
In all cells, prokaryotic and eukaryotic, RNA is ultimately derived from DNA, so mutations in the RNA can appear if the DNA polymerase makes mistakes during the replication of the DNA or if the RNA polymerase makes mistakes during the transcription of the RNA. Note that only mutations that occur during DNA replication can they become permanent and heritable. If mistakes occur during transcription, those mistakes get incorporated into that single transcript but not into other ones.
A number of viruses have RNA as their genomes and do not pass through a DNA intermediate. (Viruses are just particles of DNA or RNA, not both, that are usually covered by a protein shell. Retroviruses are RNA viruses that do pass through a DNA intermediate. They rely on a reverse transcriptase to copy the genomic RNA into DNA.) This means that not all RNA in nature is coded by DNA. RNA viruses that do not copy their genomes into DNA rely on host RNA polymerases to replicate their genomes, so mutations can arise in these cases if the RNA polymerase makes mistakes. Mutated genomes can be packaged into new virus particles and thus the mutations can be inherited.
These viral mutations can lead to disease if, for example, they help the virus evade the defense mechanisms of the host. During the replication of the HIV retrovirus, the reverse transcriptase makes mistakes often enough that it's easy for mutant viruses to appear that are resistant to anti-HIV drugs. If an AIDS patient is given a single anti-HIV drug, the viral population is soon taken over by mutants resistant to the drug. It takes longer for mutants that are simultaneously resistant to multiple anti-HIV drugs to appear. This is why AIDS treatment is generally more effective when multiple anti-HIV drugs are administered at the same time—so-called "combination therapy."
RNA can be mutated in at least one other way. There's a process called RNA editing in which mRNA is posttranscriptionally modified, resulting in a change in the coding information. For example, one or more uracil (U) residues may be inserted into, or removed from, the transcript; or cytosine (C) bases may be changed into U bases. This process occurs extensively in the mitochondria of plants and trypanosomes, and even to a certain degree in mammals. In mammals the enzymes involved are called adenosine deaminases acting on RNA (ADARs). The purpose of RNA editing remains unclear, but it's important for at least some processes in mammals. A pre-mRNA encoding an ion channel in the brain undergoes editing by a certain ADAR, and if this editing doesn't occur in mice, they suffer epileptic seizures and die before reaching adulthood.
For further information, see:
Alberts, B., et al. Molecular Biology of the Cell. 4th ed. New York: Garland Science, 2002. For general information on RNA and DNA viruses, see chapter 25 ("Pathogens, Infection, and Innate Immunity"). For information on RNA editing, see chapter 7 ("Control of Gene Expression").
Fields, B.N., et al. Fields Virology. 3rd ed. Philadelphia: Lippincott-Raven, 1996. Contains a great deal of information about viruses and their life cycles. For example, see chapter 4 ("Multiplication of Viruses: An Overview").
9/8/03
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| GUS THE FUSS |
Posted - 08/12/2007 : 22:18:20
Chris also found this which means that the RNA is a more agressive and dangerous than DNA measles.I think in vaccines they mess about with the structure of the virus and when they mutate they can be traced because of the structure found in the cells as would be diffrent from wild structure DNA or RNA .All well and above my primative brain.Below is to do with animals but one would assume the same for humans well they use animals for testing etc...
Good luck if I find anymore will post it.
http://www2.gsu.edu/~biotkf/bio475/475lecture2.htm
The genomes of RNA viruses are limited in size. The largest genome is that of the coronaviruses which is 30,000 nucleotides in length. However, the other families have genomes of between 7000 and 15,000 nucleotides. The reason for this size limitation is that the polymerases which replicate the RNAs of these viruses have no correction or proofreading system as do the DNA polymerases of cells which correct errors made by the polymerases. Polymerases make errors at a rate of between 1 in 104 to 1 in 105. Such errors can cause a fatal mutation. Therefore, the size of an RNA genome is limited by the error rate of its polymerase. Only 1 in 10 virions produced during an infection cycle is infectious. The 9/10 noninfectious particles may contain such mutations. The rapid, polymerase-induced mutation rate inherent in these RNA viruses allows these viruses to evolve rapidly in response to selective pressure (such as antibody reponse) and is responsible for epidemiological phenomena such as antigenic drift.
RNA viruses are thought to be more primitive than DNA viruses. At the beginning of cell life, RNA is thought to have been the original form of nucleic acid. Besides carrying genetic information, RNA can also serve a structural function (as in the ribosomal RNAs) and enzymatic functions have been documented. As cell life progressed, a more stable repository of genetic information (DNA) was evolved, and RNA came to be a labile species which had messenger, structural, and possibly enzymatic functions. Because RNA viruses have enzymes (RNA-dependent-RNA polymerases) which can no longer be found in cells, it is
thought that these viruses evolved at a time when these enzymes were present in cells (before the advent of DNA).
II. Capsids
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| GUS THE FUSS |
Posted - 08/12/2007 : 21:18:10
Chris if your boy never had the measels it must be the vaccine strain from the vaccines.
http://www.whale.to/vaccines/thrower45.html
A February 2004 paper (37) by Bradstreet, O’Leary, Sheils et al to the US Institute of Medicine, and subsequently published later that year, reported that three children with regressive autism had undergone cerebrospinal fluid assessment, including for measles virus. All three had had concomitant onset of gastrointestinal symptoms and had already had measles virus genomic RNA detected in biopsies of ileal-lymphoid nodular hyperplasia. None of the cases nor non-autistic controls had any history of measles exposure other than possibly via MMR. Serum and cerebrospinal fluid samples were also evaluated for antibodies to measles virus and myelin basic protein. The result was that measles virus f-gene was present in the cerebrospinal fluid of all three autistic cases but not in non-autistic controls. Further, serum anti-myelin basic protein autoantibodies were detected in all children with autistic encephalopathy. Anti-MBP and measles virus antibodies were detected in the CSF of two cases, but the third had neither. The study concluded that the findings were consistent with a measles-virus etiology for autistic encephalopathy, indicating the possibility of a virally-driven cerebral immunopathology in some cases of regressive autism. The virus genome found in the autistic children was “exclusively consistent with vaccine strain”.
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| cfish |
Posted - 08/12/2007 : 20:17:09
thanks gus i did find that already but still not much wiser i think will have to look for a doctor to explain it to us and the rest of the documents thanks again . chris |
| GUS THE FUSS |
Posted - 08/12/2007 : 00:09:30
Dont know if this helps but got this of Wilkipedia.. you probably have looked it up.There is more in WHALE Dr Wakefield refers to it a bit in WHALE.If you click the link there are a lot of references to the words below that can be clicked on rather than reading it below.
http://en.wikipedia.org/wiki/RNA_virus
RNA virus
From Wikipedia, the free encyclopedia
Jump to: navigation, search
An RNA virus is a virus which belongs to either Group III, Group IV or Group V of the Baltimore classification system of classifying viruses. As such, they possess ribonucleic acid (RNA) as their genetic material and do not replicate using a DNA intermediate. The nucleic acid is usually single-stranded RNA (ssRNA) but can occasionally be double-stranded RNA (dsRNA). Notable human pathogenic RNA viruses include SARS, Influenza and Hepatitis C viruses. Walter Fiers (University of Ghent, Belgium) was the first to establish the complete nucleotide sequence of a gene (1972) and of the viral genome of a virus: Bacteriophage MS2-RNA (1976)[1]
Contents [hide]
1 Characteristics
1.1 RNA Sense
1.2 Mutation rates
2 Replication
3 Group III - dsRNA viruses
4 Group IV - positive-sense ssRNA viruses
5 Group V - negative-sense ssRNA viruses
6 See also
7 References
8 External link
[edit] Characteristics
[edit] RNA Sense
Main article: Sense (molecular biology)
RNA viruses can be further classified according to the sense or polarity of their RNA into negative-sense and positive-sense RNA viruses. Positive-sense viral RNA is identical to viral mRNA and thus can be immediately translated by the host cell. Negative-sense viral RNA is complementary to mRNA and thus must be converted to positive-sense RNA by an RNA polymerase before translation. As such, purified RNA of a positive-sense virus can directly cause infection though it may be less infectious than the whole virus particle. Purified RNA of a negative-sense virus is not infectious by itself as it needs to be transcribed into positive-sense RNA.
[edit] Mutation rates
RNA viruses generally have very high mutation rates as they lack DNA polymerases which can find and fix mistakes, and are therefore unable to conduct DNA repair of damaged genetic material. DNA viruses have considerably lower mutation rates due to the proof-reading ability of DNA polymerases within the host cell. Retroviruses integrate a DNA intermediate of their RNA genome into the host genome, and therefore have a higher chance of correcting any mistakes in their genome thanks to the action of proof-reading DNA polymerases belonging to the host cell.
Although RNA usually mutates rapidly, recent work found that the SARS virus and related RNA viruses contain a gene that mutates very slowly.[2] The gene in question has a complex three-dimensional structure which is hypothesized to provide a chemical function necessary for viral propagation, perhaps as a ribozyme. If so, most mutations would render it unfit for that purpose and would not propagate.
[edit] Replication
Animal RNA viruses can be placed into about four different groups depending on their mode of replication.
Positive-sense viruses have their genome directly utilized as if it were mRNA, producing a single protein which is modified by host and viral proteins to form the various proteins needed for replication. One of these includes RNA replicase, which copies the viral RNA to form a double-stranded replicative form, in turn this directs the formation of new virions.
Negative-sense viruses must have their genome copied by a RNA polymerase or transcriptase to form positive-sense RNA. This means that the virus must bring along with it the RNA-dependent RNA polymerase enzyme. The positive-sense RNA molecule then acts as viral mRNA, which is translated into proteins by the host ribosomes. The resultant protein goes on to direct the synthesis of new virions, such as capsid proteins and RNA replicase, which is used to produce new negative-sense RNA molecules.
Double-stranded reoviruses contain up to a dozen different RNA molecules which each code for a mRNA. These all associate with proteins to form a single large complex which is replicated using virally-encoded replicase to form new virions.
Retroviruses are single-stranded but unlike other single-stranded RNA viruses they use DNA intermediates to replicate. Reverse transcriptase, a viral enzyme that comes from the virus itself after it is uncoated, converts the viral RNA into a complementary strand of DNA, which is copied to produce a double stranded molecule of viral DNA. This DNA goes on to direct the formation of new virions.
[edit] Group III - dsRNA viruses
Family Birnaviridae
Family Chrysoviridae
Family Cystoviridae
Family Hypoviridae
Family Partitiviridae
Family Reoviridae - includes Rotavirus
Family Totiviridae
Unassigned genera
Endornavirus
[edit] Group IV - positive-sense ssRNA viruses
Order Nidovirales
Family Arteriviridae
Family Coronaviridae - includes Coronavirus, SARS
Family Roniviridae
Unassigned
Family Astroviridae
Family Barnaviridae
Family Bromoviridae
Family Caliciviridae - includes Norwalk virus
Family Closteroviridae
Family Comoviridae
Family Dicistroviridae
Family Flaviviridae - includes Yellow fever virus, West Nile virus, Hepatitis C virus, Dengue fever virus
Family Flexiviridae
Family Hepeviridae - includes Hepatitis E virus
Family Leviviridae
Family Luteoviridae - includes Barley yellow dwarf virus
Family Marnaviridae
Family Narnaviridae
Family Nodaviridae
Family Picornaviridae - includes Poliovirus, the common cold virus, Hepatitis A virus
Family Potyviridae
Family Sequiviridae
Family Tetraviridae
Family Togaviridae - includes Rubella virus, Ross River virus, Sindbis virus
Family Tombusviridae
Family Tymoviridae
Unassigned genera
Genus Benyvirus
Genus Cheravirus
Genus Furovirus
Genus Hordeivirus
Genus Idaeovirus
Genus Machlomovirus
Genus Ourmiavirus
Genus Pecluvirus
Genus Pomovirus
Genus Sadwavirus
Genus Sobemovirus
Genus Tobamovirus - includes tobacco mosaic virus
Genus Tobravirus
Genus Umbravirus
[edit] Group V - negative-sense ssRNA viruses
Order Mononegavirales
Family Bornaviridae - Borna disease virus
Family Filoviridae - includes Ebola virus, Marburg virus
Family Paramyxoviridae - includes Measles virus, Mumps virus, Nipah virus, Hendra virus
Family Rhabdoviridae - includes Rabies virus
Unassigned
Family Arenaviridae - includes Lassa virus
Family Bunyaviridae - includes Hantavirus
Family Orthomyxoviridae - includes Influenza viruses
Unassigned genera:
Genus Deltavirus
Genus Ophiovirus
Genus Tenuivirus
Genus Varicosavirus
[edit] See also
Virus classification
Viral replication
Positive/negative-sense
[edit] References
^ Fiers W et al., Complete nucleotide-sequence of bacteriophage MS2-RNA - primary and secondary structure of replicase gene, Nature, 260, 500-507, 1976
^ Robertson MP, Igel H, Baertsch R, Haussler D, Ares M Jr, Scott WG (2005). "The structure of a rigorously conserved RNA element within the SARS virus genome". PLoS Biol 3 (1): e5. PMID 15630477 DOI:10.1371/journal.pbio.0030005.
Prescott, L. (1993). Microbiology, Wm. C. Brown Publishers, ISBN 0-697-01372-3
[edit] External link
MeSH RNA Viruses
This virus-related article is a stub. You can help Wikipedia by expanding it.
Retrieved from "http://en.wikipedia.org/wiki/RNA_virus"
Categories: Virus stubs | Virology | RNA
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