Chapter 4 bacteriophage
Chapter 4 bacteriophage
Bacteriophages( phages )are obligate intracellular parasites that multiply inside bacteria by making use of some or all of the host biosynthetic machinery. They are viruses that infect bacteria
◼ Bacteriophages ( phages ) are obligate intracellular parasites that multiply inside bacteria by making use of some or all of the host biosynthetic machinery . They are viruses that infect bacteria
Composition of Bacteriophage Nucleic acid: either dna or rna but not both ds dNa Ss rNa ss dna unusual or modified bases encode 3-5 gene products to over 100 gene products Protein function in infection and protect the nucleic acid
Composition of Bacteriophage ◼ Nucleic acid: either DNA or RNA but not both ◼ ds DNA, ss RNA, ss DNA ◼ unusual or modified bases ◼ encode 3-5 gene products to over 100 gene products ◼ Protein: function in infection and protect the nucleic acid
Structure of Bacteriophage different sizes and shapes T3 phage icosahedral head 0x60nm.+面体 tail 20nm long T4 phage dsDNA T1 phage head 80x 11Onm dsDN tail 110nm long head 54x54nm tail 140nm long M13 phage filamentous BSDNA helical 80010nm
Structure of Bacteriophage ◼ different sizes and shapes icosahedral 二十面体 filamentous
Capsid DNA Head Contractile Sheath Tail Tail fibers Base plate
Tail Tail Fibers Base Plate Head Contractile Sheath Capsid DNA
Head Tail e fibers 100 nm
Viral morphology in a saline wetland
Types of Bacteriophage Lytic or virulent Phages 毒性噬菌体 Lysogenic or Temperate Phage 溶原性噬菌体或温和噬菌体
Types of Bacteriophage ◼ Lytic or Virulent Phages 毒性噬菌体 ◼ Lysogenic or Temperate Phage 溶原性噬菌体或温和噬菌体
Lytic or Virulent Phages Definition Lytic or virulent phages are phages which can only multiply in bacteria and kill the cell by lysis at the end of the life cycle
Lytic or Virulent Phages ◼ Definition: Lytic or virulent phages are phages which can only multiply in bacteria and kill the cell by lysis at the end of the life cycle