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B. acteriophages. Bacteriophages. They are viruses that infect bacteria i.e. bacterial viruses (bacteria eater). 1-Discovery. 3-Replication. Main items. 2-General characteristics. 4-Importance. 1-Discovery. Main items. D “ herelle (1917). Twort (1915). Discovery.
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B acteriophages
Bacteriophages They are viruses that infect bacteria i.e. bacterial viruses (bacteria eater).
1-Discovery 3-Replication Main items 2-General characteristics 4-Importance
1-Discovery Main items
D“herelle (1917) Twort (1915) Discovery
Bacteria + solid agar Thermal treatment Lytic agent may be a virus
Bacillus dysentrae + solid agar Phenomenon due to bacteriophage
1-Discovery Main items 2-General characteristics
General characteristics • Widely distributed. • Structure. • Symmetry. • Nucleic acid. • Morphology. • Replication. • Size • Cultivation.
General characteristics • Widely distributed. • Structure. • Symmetry. • Nucleic acid. • Morphology. • Replication. • Size • Cultivation.
General characteristics • Widely distributed. • Structure. • Symmetry. • Nucleic acid. • Morphology. • Replication. • Size. • Cultivation.
Symmetry : 1.Helical 2. Cubic
General characteristics • Widely distributed. • Structure. • Symmetry. • Nucleic acid. • Morphology. • Replication. • Size. • Cultivation.
General characteristics • Widely distributed. • Structure. • Symmetry. • Nucleic acid. • Morphology. • Replication. • Size. • Cultivation.
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General characteristics • Widely distributed. • Structure. • Symmetry. • Nucleic acid. • Morphology. • Replication. • Size. • Cultivation.
Replication 1. Virulent (Lytic) 2. Avirulent (lysogenic or temperate)
General characteristics • Widely distributed. • Structure. • Symmetry. • Nucleic acid. • Morphology. • Replication. • Size. • Cultivation.
1-Discovery 3-Replication Main items 2-General characteristics
Lytic cycle Replication Releasing Adsorption Assembly Penetration
Lysogeny cycle Integration Releasing Adsorption Assembly Penetration Replication Bacterial duplication Spontaneous induction
Mutation of temperate phage to virulent phage • Resistant to repressor molecule . • Loss repressor molecule production.