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MindMap Gallery microbiology viruses
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microbiology viruses
This is a mind map about viruses. The main contents include: the morphological structure of virus particles (virions), plant viruses and insect viruses, the proliferation of viruses, viruses and their characteristics.
Edited at 2024-03-03 01:11:54
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Virus
Viruses and their characteristics
Definition: A class of obligate intracellular parasitic non-cellular microorganisms composed of nucleic acids and proteins.
Virus characteristics
Small size (nm level: can pass bacterial filter)
No cell structure, composed of nucleic acids and proteins
Obligate living cell parasitism (no productivity enzyme system and protein synthesis system), no growth, only proliferation (molecular replication, component assembly)
In the form of non-living macromolecules under in vitro conditions (potentially infectious, showing characteristics of proliferation, inheritance, mutation, and evolution in living cells)
Not sensitive to general antibiotics, sensitive to interferon
virus group
True viruses (proteins and nucleic acids)
Subvirus
viroid (RNA)
satellite virus, satellite nucleic acid (RNA)
Prions (proteins)
Morphological structure of virus particles (virions)
Definition: Mature viral individuals with infectious activity
Morphological characteristics
form
Rod-shaped or filament-shaped (more common in plant viruses)
Polyhedron or sphere (more common in animal viruses and fungal viruses)
Tadpole shape (more common in bacteriophages)
size
Unit of measurement:nm
The size of virus particles is about 10~400nm
structure and composition
naked virus
nucleocapsid
capsid
Composition: Assembled by capsomelin subunits
Function: Protect nucleic acids
structure
spiral symmetry
The rod length is 300nm, the width is 15nm, and the hollow inner diameter is 4nm.
Capsid: 2130 capsomeres (each capsomere contains 158 amino acids), 130 turns of helix
Nucleic acid: ssRNA (6390 nucleotides), every three amino acids are combined with a capsomere and coiled in the capsid cavity
icosahedral symmetry
20 faces, 12 corners, 30 sides
compound symmetry
Head: icosahedral symmetric capsid
Tail: helical symmetry capsid
core
Composition: nucleic acid
type
DNA
Single stranded (ss) or double stranded (ds), circular or linear
RNA
ss or ds; positive strand ( ) or negative strand (-); circular or linear
enveloped virus
nucleocapsid
envelope
Definition: The outer lipoprotein membrane of some viral nucleocapsids
Chemical composition: lipids, proteins and glycoproteins
Most enveloped viruses are spherical or polymorphous, while poxviruses are brick-shaped.
Function: Maintain virus structure, protect virus nucleocapsid, adsorb infection
multiplication of virus
Definition: After the virus infects the host cell, the viral nucleic acid enters the cell, replicates and expresses, synthesizes viral components, assembles progeny virions, and releases them outside the cell in a certain way.
Proliferation process (taking phage as an example)
virulent bacteriophage
Infection of host bacteria causes bacterial cell rupture and death
process
Adsorption
Bacteriophages are specifically recognized by adsorption proteins and bind to receptors on host bacterial cells.
invade
Configuration stimulation - tail filament - tail plate - tail sheath deformation - tail tube enters host cell, phage nucleic acid is injected into the cell
Biosynthesis
Process: The phage genome enters and changes the host cell metabolism. The virus uses the place, energy, and raw materials provided by the cell to complete the replication of viral nucleic acid and protein nucleic acid.
Expression timing: early expression - mid-term expression (nucleic acid replication) - late expression
Assembly (self-ordered assembly)
freed
Plaque: Bacteriophages continuously and repeatedly infect and lyse host bacterial cells, resulting in transparent plaques visible to the naked eye on the bacterial lawn.
temperate bacteriophage
Definition: Infection of host bacteria generally does not result in bacterial rupture and death, and most cells grow normally
Example: Lambda phage infecting E.coli
process
Adsorption
invade
Lysogeny cycle (inserting genes of phages (prophages) into genes of infected bacteria (lysogens))
Integrate
Synchronous replication
Integrate
Lytic cycle (lysogenic bacteria spontaneously or induced lysis under specific conditions)
Biosynthesis
assembly
freed
Plant viruses and insect viruses
insect virus
Viruses that infect and live inside insects
Parasitic insects: Lepidoptera, Hymenoptera, Coleoptera, Hemiptera, Neuroptera, Trichoptera, insects
type
Inclusion body: a structure formed by the accumulation of virus particles in the cytoplasm or nucleus of a host cell
Inclusion bodies in the nucleus of insect cells - Nuclear Polyhedrosis Virus (NPV)
Inclusion bodies in the cytoplasm of insect cells—Plasmic polyhedrosis virus (CPV)
Inclusion bodies in the nucleus or cytoplasm of insect cells - particulate viruses
non-inclusion body virus
plant viruses
Parasitic in plant cells. Most seed plants are susceptible to viral diseases
Host plants: Gramineae, Cucurbitaceae, Leguminosae, Brassicaceae, Rosaceae plants
viral infection symptoms
Leaf color is mottled and withered
Leaves yellow-green, yellow, red
Deformities: rolled leaves, shrunken leaves, shrinking, clustering, dwarfing, etc.
application
Anti-insect biopesticides
Insecticidal properties: high specificity, strong diffusibility, high toxicity, long-lasting effects, no environmental pollution, and safe for humans and animals
Spontaneous, induced lysis
Induced lysis: Appropriate amounts of physical and chemical factors (such as ultraviolet rays, rays, chemical mutagens, mitomycin C, etc.) induce massive lysis of lysogenic bacteria
Spontaneous lysis: Mild phages in a very small number of lysogenic bacteria spontaneously deintegrate and lyse host bacterial cells. Very low cleavage frequency