Download Document

TORTORA  FUNKE  CASE
ninth edition
MICROBIOLOGY
an introduction
13
Part B
Viruses, Viroids,
and Prions
PowerPoint® Lecture Slide Presentation prepared by Christine L. Case
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Attachment, Penetration, and Uncoating
 Pinocytosis
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 13.14a
Attachment, Penetration, and Uncoating
 Fusion
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 13.14b
Release of an Enveloped Virus by Budding
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 13.20
Multiplication of DNA Virus
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 13.15
+ Sense Strand (+ Strand) RNA Virus
Attachment
Capsid
Nucleus
RNA
Cytoplasm
Host cell
Entry
and uncoating
Maturation
and release
Translation and synthesis
of viral proteins
RNA replication by viral RNAdependent RNA polymerase
Uncoating releases
viral RNA and proteins.
– strand is transcribed
from + viral genome.
Capsid
protein
+ strand
mRNA is transcribed
from the – strand.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Viral
genome
(RNA)
Viral
protein
(a) ssRNA; +
or sense strand;
Picornaviridae
Figure 13.17a
— Antisense Strand (— Strand) RNA Virus
Attachment
Capsid
Nucleus
RNA
Cytoplasm
Host cell
Entry
and uncoating
Maturation
and release
Translation and synthesis
of viral proteins
RNA replication by viral RNAdependent RNA polymerase
The + strand (mRNA) must first
be transcribed from the – viral
genome before proteins can
be synthesized.
Uncoating releases
viral RNA and proteins.
Viral
Viral
protein
genome
(RNA)
Capsid
protein
– strands are
incorporated
into capsid
Additional – strands are
transcribed from mRNA.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
(b) ssRNA; – or
antisense strand;
Rhabdoviridae
Figure 13.17b
Double-Stranded RNA Virus
Attachment
Capsid
Nucleus
RNA
Cytoplasm
Host cell
Entry
and uncoating
Maturation
and release
Translation and synthesis
of viral proteins
RNA polymerase initiates production of
– strands. The mRNA and – strands form the
dsRNA that is incorporated as new viral genome.
RNA replication by viral RNAdependent RNA polymerase
mRNA is produced inside the
capsid and released into the
cytoplasm of the host.
Capsid proteins and RNAdependent RNA polymerase
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Uncoating releases
viral RNA and proteins.
Viral
genome
(RNA)
Viral
protein
(c) dsRNA; + or sense
strand with – or
antisense strand;
Reoviridae
Figure 13.17c
Pathways of Multiplication
for RNA-Containing Viruses
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 13.17
Multiplication of a Retrovirus
PLAY
Animation: Viral Replication
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 13.19
DNA and RNA Viruses Compared
 DNA: Cellular enzyme transcribes viral DNA in nucleus.
 DNA, reverse transcriptase: Cellular enzyme
transcribes viral DNA in nucleus; reverse transcriptase
copies mRNA to make viral DNA.
 RNA, + strand: Viral RNA is a template for synthesis of
RNA polymerase.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
DNA and RNA Viruses Compared
 RNA – strand: Viral enzyme copies viral RNA to make
mRNA in cytoplasm.
 RNA, double-stranded: Viral enzyme copies – strand
RNA to make mRNA in cytoplasm.
 RNA, reverse transcriptase: Viral enzyme copes viral
RNA to make DNA in cytoplasm.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Cancer
 Activated oncogenes transform normal cells into
cancerous cells.
 Transformed cells have increased growth, loss of
contact inhibition, tumor specific transplant and T
antigens.
 The genetic material of oncogenic viruses becomes
integrated into the host cell's DNA.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Oncogenic Viruses
 Oncogenic DNA viruses
 Oncogenic RNA viruses
 Adenoviridae
 Retroviridae
 Heresviridae
 Viral RNA is transcribed
 Poxviridae
to DNA which can
 Papovaviridae
integrate into host DNA
 Hepadnaviridae
 HTLV 1
 HTLV 2
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
 Latent viral infections
 Virus remains in asymptomatic host
cell for long periods.
 Cold sores, shingles
 Presistent viral infections
 Disease processes occurs over a
long period; generally is fatal.
 Subacute sclerosing
panencephalitis (measles virus)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 13.21
Prions
 Infectious proteins
 Inherited and transmissible by ingestion, transplant, and
surgical instruments
 Spongiform encephalopathies: Sheep scrapie, CreutzfeldtJakob disease, Gerstmann-Sträussler-Scheinker syndrome,
fatal familial insomnia, mad cow disease
 PrPC: Normal cellular prion protein, on cell surface
 PrPSc: Scrapie protein; accumulates in brain cells forming
plaques
PLAY
Animation: Prion Reproduction
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Prions
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 13.22
 Plant viruses: Enter
through wounds or
via insects.
 Viroids: Infectious
RNA; e.g., potato
spindle tuber
disease.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 13.23
Some Plant Viruses
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.6
Virus Families
 Single-stranded DNA,
nonenveloped viruses
 Parvoviridae
 Human parvovirus
 Fifth disease
 Anemia in
immunocompromised
patients
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (1 of 20)
Double-Stranded DNA, Nonenveloped Viruses
 Mastadenovirus
 Respiratory infections
in humans
 Tumors in animals
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (2 of 20)
Double-Stranded DNA, Nonenveloped Viruses
 Papillomavirus (human
wart virus)
 Polyomavirus
 Cause tumors; some
cause cancer
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (3 of 20)
Double-Stranded DNA, Enveloped Viruses
 Orthopoxvirus (vaccinia
and smallpox viruses)
 Molluscipoxvirus
 Smallpox
 Molluscum
contagiosum
 Cowpox
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (4 of 20)
Double-Stranded DNA, Enveloped Viruses
 Simplexvirus (HHV1 and HHV 2)
 Varicellavirus (HHV 3)
 Lymphocryptovirus (HHV 4)
 Cytomegalovirus (HHV 5)
 Roseolovirus (HHV 6)
 HHV 7
 Kaposi's sarcoma (HHV 8)
 Some herpesviruses can
remain latent in host cells.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (5 of 20)
Double-Stranded DNA, Enveloped Viruses
 Hepadnavirus (Hepatitis
B virus)
 Use reverse
transcriptase to
produce DNA from
mRNA.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (6 of 20)
Single-Stranded RNA, + Strand,
Nonenveloped
 Enterovirus
 Enteroviruses include
poliovirus and
coxsackievirus.
 Rhinovirus
 Hepatitis A virus
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (7 of 20)
Single-Stranded RNA, + Strand,
Nonenveloped
 Hepatitis E virus
 Norovirus causes
gastroenteritis.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (8 of 20)
Single-Stranded RNA, + Strand, Enveloped
 Alphavirus
 Alphaviruses are
transmitted by arthropods;
include EEE, WEE.
 Rubivirus (rubella virus)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (9 of 20)
Single-Stranded RNA, + Strand, Enveloped
 Arboviruses can replicate
in arthropods; include
yellow fever, dengue,
SLE, and West Nile
viruses
 Hepatitis C virus
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (10 of 20)
Single-Stranded RNA, + Strand, Enveloped
 Coronavirus
 Upper respiratory
infections
 SARS
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (11 of 20)
Single-Stranded RNA, – Strand,
One RNA Strand
 Vesiculovirus
 Lyssavirus (rabies virus)
 Cause numerous animal
diseases
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (12 of 20)
Single-Stranded RNA, – Strand,
One RNA Strand
 Filovirus
 Enveloped, helical
viruses
 Ebola and Marburg
viruses
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (13 of 20)
Single-Stranded RNA, – Strand,
One RNA Strand
 Paramyxovirus
 Morbillivirus
 Paramyxovirus
 Parainfluenza
 Mumps
 Newcastle disease
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (14 of 20)
Single-Stranded RNA, – Strand,
One RNA Strand
 Hepatitis D virus
 Depends on
coinfection with
Hepadnavirus
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (15 of 20)
Single-Stranded RNA, – Strand,
Multiple RNA Strands
 Influenzavirus (Influenza
viruses A and B)
 Influenza C virus
 Envelope spikes can
agglutinate RBCs.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (16 of 20)
Crossing the Species Barrier
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
UN 13.3
Single-Stranded RNA, – Strand,
Multiple RNA Strands
 Bunyavirus (CE virus)
 Hantavirus
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (17 of 20)
Single-Stranded RNA, – Strand,
Multiple RNA Strands
 Arenavirus
 Helical capsids contain
RNA-containing
granules
 Lymphocytic
choriomeningitis
 VEE and Lassa Fever
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (18 of 20)
Single-Stranded RNA, Two RNA Strands,
Produce DNA
 Lentivirus (HIV)
 Oncogenic viruses
 Use reverse
transcriptase to
produce DNA from
viral genome.
 Includes all RNA tumor
viruses
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (19 of 20)
Double-Stranded RNA, Nonenveloped
 Reovirus (Respiratory
Enteric Orphan)
 Rotavirus
 Mild respiratory
infections and
gastroenteritis
 Colorado tick fever
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 13.2 (20 of 20)