Tobacco mosaic viruses. Colored transmission
electron micrograph of a cluster of rod-shaped red virus particles of tobacco
mosaic virus (TMV). Each virus consists of a protein coat with internal RNA
genetic material. Some viruses are attached end-to-end. The virus enters
a host cell in a tobacco plant and commandeers its DNA, instructing it to
reproduce more TMV's. The effect of TMV infection varies from outright death
of the host plant to severe lesions or mottling of the leaves. Plant viruses
like TMV are transmitted by insects, pests and nematode worms. Negatively
stained. Magnification: unknown.
Credit: Dr. Linda Stannard, UCT / Photo Researchers, Inc.
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False-color transmission electron
micrograph of rod-shaped virus particles of tobacco mosaic virus (TMV). Inside
the rod, protein
molecules are wound helically down the full length of the virus, housing & protecting
the nucleic acid of RNA. The virus enters a host cell in a tobacco plant & commandeers
its DNA, instructing it to code for TMV's own nucleic acids. The effect of
TMV infection varies from outright death of the host plant or severe lesions
resembling burn marks on the surface of the leaves to mottling of the leaves.
Plant viruses like TMV are transmitted by insects, pests & nematode worms.
Magnification: x34,000 at 6x4.5cm size.
Credit: Dr. Jeremy Burgess / Photo Researchers, Inc.
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