上海交通大学：《医学微生物》课程教学资源（PPT课件讲稿）英文版 chapter 4 bacteriophage

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