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AIDS ( Acquired Immunodeficiency Syndrome)
no cure or vaccine
AIDS is caused by the virus HIV (Human Immunodeficiency Virus)
HIV – spherical in shape, resembling a 20-sided soccer ball.
HIV attacks the immune system
Cannot be seen with naked eye or the light microscope, only with electron microscope
It is a parasite
HIV discovered in 1884 with the development of a porcelain filter by Charles
Chamberland, who was working in the laboratory of Louis Pasteur
A few years later 1898, Dmitri Ivanowski took the mottled, dying leaves from a
tobacco plant with mosaic disease, ground them up, and filtered the extract through
a Chamberland filter. When the recovered sap was introduced into healthy plants, it
produced the symptoms of disease as did the unfiltered sap.
Renato Dulbecco – discovered the virus had been incorporated into the host cell
genes and behaved as if it were a part of the cell’s genetic apparatus. The virus DNA
was not a part of the cell’s heredity.
RSV (Rous sarcoma virus) – chicken tumours
Temin and Baltimore – showed that a specific enzyme, reverse transcriptase, in
RSB was able to make a DNA copy form the virus’s RNA. Individually showed that
the replication of RNA viruses involves the transfer of information from the viral
DNA copy, and that the viral DNA was integrated into the chromosomes of the
transformed cancer cells.
Purified DNA from transformed cancer cell, when introduced into normal cells,
caused the production of new RNA tumour viruses
RSV was a cancer causing retrovirus.
Retrovirus - reverse transcriptase
HIV-1: found throughout the world
HIV-2: found primarily in West Africa
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