Lecture 12 - Chapter 13 Characterizing And Classifying Virus, Viroids And Prions

Front 1

Viruses

Back 1

•Infectious Agent

•Replicate inside other cells

•Infect Prokaryotes & eukaryotes

•Genetic Material: single stranded or double stranded DNA or RNA

Front 2

Virions

Back 2

Viruses that exist outside of cells, in the form of independent particles

Front 3

Morphology

Back 3

•Helical

•Icosahedral- Twenty face structure

•Prolate- Elongated icosahedral

Front 4

Genetic Material

Back 4

•DNA or RNA

•Single Or double stranded

•Linear Or circular

•Positive Sense or Negative sense

Front 5

Viral Envelope

Back 5

•Composed portions of the host membrane

•Contain host proteins

•Allow viruses to evade host defenses

•Identify & bind to receptors on host cells

Front 6

Viral Envelope is bilayer?

Back 6

Phospholipid Bilayer

Front 7

Viral envelope is susceptible to?

Back 7

Heat, desiccation, chemicals

Front 8

Viral enveloped viruses are less able to?

Back 8

Survive harsh environments

Front 9

Viral Reproduction: Lytic cycle

Back 9

•Viral genome exist separate from the host genome

• Replication of viral particles cause destruction of the host

Front 10

Viral Reproduction: Lysogenic cycle

Back 10

• Viral genome is integrated into host genome

• Replicated along w/host replication

Front 11

Viral Reproduction: Attachment

Back 11

Specific proteins on viral capsid/envelope recognizes receptors on the surface of host cells

Front 12

Viral Reproduction: Penetration

Back 12

Viral entry through endocytosis or membrane fusion

Front 13

Viral Reproduction: Uncoating

Back 13

Viral capsid degraded through viral or host enzymes

Front 14

Viral Reproduction: Replication

Back 14

Viral genome & proteins

Front 15

Viral Reproduction: Assembly

Back 15

Virus proteins & genome self assemble into viral particles

Front 16

Viral Reproduction: Releases

Back 16

Lysis or budding

Front 17

ViralClassification: dsDNA

Back 17

Double Stranded DNA

Front 18

ViralClassification: ssDNA

Back 18

Single Stranded DNA

Front 19

Viral Classification: dsRNA

Back 19

Double Stranded RNA

Front 20

Viral Classification: (+)ssRNA

Back 20

Positive sense single stranded RNA

Front 21

Viral Classification: (-)ssRNA

Back 21

Negative sense single stranded RNA

Front 22

Viral Classification: ssRNA-RT

Back 22

Single stranded RNA - Reverse Transcription

Front 23

Viral Classification: dsDNA-RT

Back 23

Double stranded DNA - Reverse Transcription

Front 24

dsDNA and ssDNA uses?

Back 24

DNA dependent DNA polymerase to replicate the genetic material

Front 25

ssDNA would often require the formation of?

Back 25

complementary strand before replication can occur

Front 26

dsDNA - Herpesviridae -(enveloped icosahedral)

Back 26

• fever blisters (HSV-1)

•chickenpox (varicella-zoster)

• mononucleosis (Epstein-Barr virus)

• Develop latent state

• subfamily alpha cytopathic effect on cells become multinucleated giant syncytial cells w/intranuclear inclusion bodies
• Held at bay by the cell-mediated immune response

Front 27

dsDNA - Adenoviridae - (naked icosahedral)

Back 27

•Infection: in rhinitis, conjunctivitis, sore throat & cough.
•Lead to lower respiratory tract pneumonia in children

Viral respiratory illness in children: RSV; Parainfluenza; Rhinovirus; Adenoviridae

Hint 27

•ADEN cause upper respiratory tract infections

•Visualize A DEN full of coughing, sneezing children

Front 28

dsDNA - Papillomaviridae - (naked icosahedral)

Back 28

• warty growths on rabbits

• icosahedral capsids appear knobby spheres

• cervical & penis cancerous

Hint 28

Think of PAPilloma virus & the PAP smear, used to detect early dysplastic cellular changes

Front 29

dsDNA - Poxviridae - (envelope icosahedral)

Back 29

•Center a large complex DNA genome coding for 100 of proteins.

• DNA organized into dumbbell shaped w/structural proteins, surround by 2 envelopes

• Virus carries own enzymes & replicates in cytoplasm

Hint 29

Brick-shaped box, POX in a box

Use to cause smallpox eradicated 1977!

Front 30

ssDNA - Parvoviridae - (naked icosahedral)

Back 30

• Childhood disease "erythema infectiosum" (5th disease)

• characterized by fever & "slapped face" rash on cheeks

Hint 30

• PAR is the smallest icosahedral virus & ssDNA

• Simple as a Par-ONE golf course!

Front 31

Parvoviridae - (naked icosahedral)

Back 31

O for circular dsDNA (naked icosahedral capsid)
O for round warts

O for round cervix

Hint 31

With these viruses think of O

Front 32

Parvoviridae - (naked icosahedral)

Back 32

PA: PApilloma virus cause human warts & cervical cancer

PO: POlyomavirus 2 members: human BK & JC virus

VA: Simian VAcuolating doesn't infect humans

Hint 32

3 members of the PA-PO-VA VIRIDAE:

Front 33

dsRNA uses RNA dependent RNA polymerase to?

Back 33

Create mRNA transcripts

Front 34

dsRNA - mRNA transcripts can be translated into?

Back 34

Proteins

Front 35

3 of the DNA viruses have envelopes?

Back 35

Herpes

Hepadna

Pox

Front 36

3 are naked: A woman must be naked for the PAP smear exam?

Back 36

PApova Adeno PArvo

Front 37

dsRNA is what type of virus?

Back 37

Rotavirus

Hint 37

Respiratory Enteric Orphan - leading causes acute infectious diarrhea & major infant mortaliy worldwide

Front 38

(+)ssRNA can act directly as?

Back 38

mRNA

Front 39

(+)ssRNA translate into?

Back 39

proteins

Front 40

(+)ssRNA must create complementary (negative sense) copy of RNA & use?

Back 40

Negative sense copy to replicate the (+)ssRNA

Front 41

(+)ssRNA: Coronaviridae (Coronavirus)

Back 41

• common cold

• envelope

• single stranded

• breakout of SARS (severe acute respiratory syndrome)

Hint 41

Rhino with common cold, drinking a Corona beer

Front 42

(+)ssRNA:Picornaviridae (Poliovirus, Rhinovirus, Hepatitis A)

Back 42

ENTERO = GI, fecal-oral transmission

• Poliovirus

• Rhinovirus

• Hepatitis A

Hint 42

•Infect intestinal epithelial & lymphoid (tonsils, Peyer's patches cells)

• Excreted in feces & spread by fecal-oral route

Front 43

(+)ssRNA: Caliciviridae (Norwalk)

Back 43

• Caliciviridae - infects young children & infants. Gastroenteritis is indistinguishable diarrhea, vomiting & fever

• Norwalk - adults, Norwalk, Ohio, elementary school. 50% students developed diarrhea & vomiting

Hint 43

DIARRHEA = DEATH BY DEHYDRATION

Front 44

(+)ssRNA: Flaviviridae (West Nile virus, Hepatitis C, Dengue)

Back 44

•Flaviviridae - cause encephalitis based on location. Spread: mosquito vector, infect human & birds

• West Nile

• Hepatitis C
• Dengue

Front 45

(+)ssRNA: Flaviviridae: West Nile Virus

Back 45

•Human disease in N.America; meningitis & encephalitis.

•Found in Africa, Europe, Middle East & Asia.

•Spread by bird or mosquito traveling on airplane migrating birds.

Front 46

(+)ssRNA: Flaviviridae:Hepatitis C

Back 46

Chronic hepatitis in U.S. Leading indication for liver transplantation

Front 47

(+)ssRNA: Flaviviridae:Dengue

Back 47

• mosquito-borne febrile disease in tropics, SW, U.S., Mexico.

• Nonsegmented RNA

• Icosahedral symmetry

• Replicates in cytoplasm

• Enveloped

Hint 47

Painful illness - break bone cause backache, muscle & joint pain, fever & headache

Front 48

(+)ssRNA: Picornaviridae: Poliovirus

Back 48

• Peyer's patches of intestine

• Motor neurons.

• Disease: paralytic poliomyelitis

• Fecal oral mode of transmission

Front 49

(+)ssRNA: Picornaviridae: Rhinovirus

Back 49

Common cold

Front 50

(+)ssRNA: Picornaviridae: Hepatitis A

Back 50

naked icosahedral HAV = Anus

Front 51

(-)ssRNA required RNA dependent RNA polymerase to create?

Back 51

A complementary copy (positive sense ssRNA)

Front 52

(-)ssRNA complementary copy can be used for?

Back 52

Translation or create copies of (-)ssRNA

Front 53

(-)ssRNA: Filoviridae (Ebola, Marburg)

Back 53

•Viruses cause hemorrhagic fever & potential bioweapons

• Humans & monkeys are infected during outbreaks. Replicated in the cytoplasm

• Nonsegmented

• Helical symmetry

• Enveloped

Hint 53

FILO = filament in latin & describes the filamentous shape of the RNA viruses

Front 54

(-)ssRNA: Paramyxoviridae (Measles, Mumps)

Back 54

Replicate in the upper respiratory tract & produce influenza-like illness, but they produce a PARAde of distinctly different diseases

Hint 54

Parainfluenza virus, mumps, measeles & respiratory syncytical virus

Front 55

(-)ssRNA: Rhabdoviridae (Rabies)

Back 55

Arboviruses transmitted: blood-sucking arthropods & cause fever & encephalitis

Front 56

(-)ssRNA: Bunyaviridae (Hantavirus)

Back 56

Arboviruses transmitted: blood-sucking arthropods & cause fever & encephalitis

Hint 56

Paul Bunyan, wear a toga, rich flavor that attracts mosquito & other arthropods. He is about to chop down a tree (ARBOL). Imagine Paul Bunyan has quite a headache (encephalitis) w/ blood-sucker clinging to his toga!

Front 57

(-)ssRNA: Orthomyxoviridae (Influenza)

Back 57

Influenza viruses cause the ORdinary

Front 58

What type of viruses are ssRNA-RT ?

Back 58

Retro viruses are enveloped viruses

Front 59

ssRNA-RT - DNA is transcribed from RNA in a process?

Back 59

Reverse transcription

Front 60

ssRNA-RT uses reverse transcriptase for?

Back 60

RNA dependent DNA polymerase

Front 61

ssRNA-RT has a virus of?

Back 61

HIV

Front 62

ssRNA-RT transcribed DNA integrate into?

Back 62

Host genome & is transcribed into ssRNA by the host

Front 63

What is dsDNA-RT?

Back 63

•Transcription Into an RNA intermediate

•RNA intermediate is reverse transcribed into DNA

Front 64

Prions does not contain?

Back 64

Nucleic acids

Front 65

Prions is an infectious particle?

Back 65

Proteinaceous

Front 66

Prions affect?

Back 66

Neutral tissues

Front 67

Inappropriate folding of the Prions proteins causes?

Back 67

Amyloid aggregates

Front 68

Prions can induce?

Back 68

Misfolding of normal proteins

Front 69

Oncovirus can cause?

Back 69

Cancer

Front 70

Oncovirus can deactivate?

Back 70

Tumor suppressor genes

Front 71

Oncovirus: Human papilloma virus (HPV)

Back 71

• Sexually transmitted

• No treatment

Hint 71

Causes cancer

Front 72

Oncovirus: Herpes virus

Back 72

• Latent state
• Cytopathic effect on cells, become multinucleated giant syncytial cells & intranuclear inclusions bodies

• Held at bay by cell-mediated immune response

Hint 72

Examples:

• Fever blisters (HPV-1)

• Chickenpox (varicella zoster)

• Mononucleosis (EPV)

Front 73

Oncovirus: Epstein-Barr virus

Back 73

• double stranded linear DNA

• Enveloped

• Icosahedral symmetry

• Transmission: intimate contact from asymptomatic shedders of EBV

• Infects human B cells & transforms cells proliferate & pass copies of EBV DNA to their progeny

Hint 73

•Causes mononucleosis

•Burkitt's lymphoma & nasopharyngeal cancer

Front 74

Oncovirus: Cytomegalovirus

Back 74

•double stranded linear DNA

•Enveloped

•Icosahedral symmetry

•Present in: milk, saliva, urine & tears

•Transmission: prolonged exposure, child w/in household, daycare centers

Hint 74

CMV is so-named caused infected cells become swollen (cytomegaly)

Front 75

(-)ssRNA: Paramyxoviridae - Measles (rubeola)

Back 75

•Negative (-) single-stranded RNA

• Unsegmented

• Lipid containing envelope

•Helical symmetry
• Replicates in the cytoplasm

• Virulence: Glycoproteins w/combined HA & NA. activity. F-protein

Front 76

(-)ssRNA: Paramyxoviridae - Mumps

Back 76

• Negative (-) single-stranded RNA

• Unsegmented

• Lipid containing envelope

• Helical symmetry

• Replicates in the cytoplasm

• Virulence: HA, no NA. F-protein

Front 77

Viruses & virions consist of what?

Back 77

•Genetic material

•Capsid (protein coat)

•Viral Envelope (lipid surrounds the capsid)