DNA Flashcards by Arriane Camacho

Virion: icosahedral

Parvoviridae
Papillomaviridae
Adenoviridae
Hepadnaviridae
Herpesviridae

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cubic symmetry

Polyomaviridae

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18-26 nm
55 nm
45 nm
70-90 nm
42nm
150-200 nm

Parvoviridae
Papillomaviridae
Polyomaviridae
Adenoviridae
Hepadnaviridae
Herpesviridae

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32 capsomeres, non-enveloped

Parvoviridae

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72 capsomeres, non-enveloped

Polyomaviridae

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252 capsomeres, non-enveloped

180 capsomeres, enveloped

Adenoviridae

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No capsomeres, enveloped

Papillomaviridae
Hepadnaviridae

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Small, heat-stable, ether resistant

Polyomaviridae

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contains fiber (unique among icosahedral viruses) that projects from each vertex

Adenoviridae

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Genome: ssDNA, linear

Parvoviridae

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Genome: dsDNA, circular

Papillomaviridae
Polyomaviridae
Hepadnaviridae

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Size:

5kB
8 kbp
130-375 kbp
3.2 kbp
125-240 kbp

Parvoviridae
Papillomaviridae
Poxviridae
Hepadnaviridae
Herpesviridae

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Genome : dsDNA, linear

Adenoviridae
Poxviridae
Herpesviridae

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• Proteins:

1 major (VP2); 1 minor (VP10 )
More than 35 proteins

Parvoviridae
Herpesviridae

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• Composition:

DNA (10%), protein (90%)

13 87

DNA (31% to 75% (G + C))

Papillomaviridae

Herpesviridae

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• Envelope: None

Papillomaviridae

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Replication: Nucleus (dependent on functions of dividing host cells)

Replication: Nucleus

Replication : Nucleus (slow growth cycle)

Replication: By means of an overlapping intermediate RNA copy of the DNA genome (HBcAg in nucleus; HBsAg in cytoplasm)

Replication: Nucleus, bud from nuclear membrane, rolling circle mechanism

Parvoviridae

Papillomaviridae

Polyomaviridae

Hepadnaviridae

Herpesviridae

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• Members: Alpha-, Gamma-, Mupa-, Nupa

Papillomaviridae

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stimulate cell DNA synthesis

Polyomaviridae
Papillomaviridae

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very small (parvus = small)

Parvoviridae

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-The human pathogen B19 has tropism for red cell progenitors

Parvoviridae

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-One genus is replication-defective and requires a helper virus

Parvoviridae

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-Transmittedthrough respiratory, transfusion, and transplacental route; distributed worldwide

Parvoviridae

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• Restricted host range and tissue tropism

Papillomaviridae

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• Significant cause of human cancer, especially cervical cancer

Papillomaviridae

•Viral oncoproteins interact with cellular tumor suppressor proteins

Papillomaviridae Polyomaviridae

•Viral oncoproteins interact with cellular tumor suppressor proteins

Papillomaviridae Polyomaviridae

• Important model tumor viruses

Polyomaviridae

•Human viruses can cause human neurologic and renal disease

Polyomaviridae

• May cause human cancer

Polyomaviridae

Parvovirinae - vertebrates

1. Parvovirus a. Erythrovirus b. Dependovirus c. Amdovirus d. Bocavirus

invertebrates

Densovirinae

vertebrates

Parvovirinae

erythema infectiosum (fifth disease)

Erythrovirus

Transient aplastic Crisis (TAC)

Erythrovirus

• Pure Red Cell Aplasia (PRCA)

Erythrovirus

hydrops fetalis

Erythrovirus

-chronic anemia in immunodeficiency syndromes

Erythrovirus

arthritis (esp. in young women)

Erythrovirus

aplastic crisis in chronic hemolytic anemia

Erythrovirus

- human parvovirus 19

Erythrovirus

- adeno-associated virus 2

Dependovirus

bovine parvovirus

Bocavirus

: acute lower respiratory tract infection, wheezing

HBoV1

: acute gastroenteritis

HBoV2-4

HPV-a (mucosa l type)

HPV-6,11 HPV-16,1 8

HPV-3 (cutaneous type)

HPV-5, 8

HPV-p (cutaneous type)

HPV-1 HPV-38

Mucosal epithelium of genital tract

HPV-6,11

Mucosal epithelium of respiratory tract

HPV-16,1 8

Skin epithelium

HPV-5, 8 HPV-1 HPV-38

Genital wart papilloma of larynx

HPV-6,11

Cervical carcinoma, oropharyngeal cancer

HPV-16,18

Skin cancer

HPV-5, 8 HPV-38

Wart

HPV-1 HPV-38

Warts (eg., cutaneous, mucosal — STI)

Papillomaviridae

Epidermodysplasia verruciformis

Papillomaviridae

Laryngeal papillomatosis

Papillomaviridae

Laryngeal papillomatosis HPV TYPES

HPV-6 and HPV-11

Cervical CA

Papillomaviridae

Cervical CA HPV TYPES

HPV-16 or HPV-18

DNA helicases, origin-binding protein

Viral transcription/replication regulator

Essential for E2 function

Membrane-associated protein, cell proliferation

Transforming protein, p53 binding

Transforming protein, pRB binding

Major capsid protein

L1 L2

JC virus progressive multifocal leukoencephalopathy (PML)

Polyomaviridae

Dementia

JC virus

Hemiparesis Disturbance of speech and vision

JC virus

• Other rare JC-associated diseases include:

1. JC virus granule cell neuronopathy 2. JC virus encephalopathy 3. JC virus meningitis

BK virus - nephropathy in transplant recipients

Polyomaviridae

rise in creatinine

•BK associated nephropathy (BKVAN)

hemorrhagic cystitis

BK virus

•post HCST renal impairment

BK viremia

Merkel cell polyomavirus (MCV)

Polyomaviridae

SV40

Polyomaviridae

KI and WU

Polyomaviridae

Characterized by infecting myelin sheath producing cells leading to speech and motor incoordination among infected individuals leading to paralysis, eventually death within 2 years

PML

astrocytes, neuron, glial cells

PMN

- UTI assoc, polyomavirus

Polyomaviridae

- Renal disease (i.e., hemorrhagic cystitis)

Polyomaviridae

- Merkel cell CA assoc. MCV

Polyomaviridae

-PML

Polyomaviridae

Hodgkins' type lymphoma

Polyomaviridae

Mastadenoviruses

Adenoviridae

Adenovirus 1-37, Enteric adenovirus 40-41

Adenoviridae

Aviadenoviruses

Adenoviridae

Common acute respiratory and gastrointestinal pathogens

Mastadenovirus Adenovirus 1-37

pharyngitis, tracheobronchitis, pneumonia laryngeal infection otitis media

Common acute respiratory and gastrointestinal pathogens

Eye infection

Mastadenovirus Adenovirus 1-37

Pharyngoconjuctival fever

Mastadenovirus Adenovirus 1-37

Epidemic keratoconjunctivitis

Mastadenovirus Adenovirus 1-37

Epidemic keratoconjunctivitis is associated with types

8,19 and 37

palpebral edema hyperemia chemosis

Epidemic keratoconjunctivitis

may developed into ipsilateral pre- auricular lymphadenopathy

Epidemic keratoconjunctivitis

Thirdmost prevalent agent of infantile gastroenteritis worldwide after Rotavirus and Norovirus

Gastroenteritis

watery diarrhea vomiting dehydration low- grade fever

Gastroenteritis

Polymerase chain reaction (PCR)

Parvoviridae Papillomaviridae Polyomaviridae Adenoviridae

Probe hybridization

Parvoviridae Papillomaviridae Polyomaviridae Adenoviridae

In situ hybridization

Parvoviridae Papillomaviridae

Detection of B19 IgM antibody and B19 IgG antibody Antigen detection assays

Parvoviridae

Immunohistochemistry In situ IF

Parvoviridae Polyomaviridae

Papanicolaou smear (PAP smear)

Papillomaviridae

Cell culture not useful

Papillomaviridae

- Using electron microscopy - Urine cytology (JCV or BKV)

Polyomaviridae

Radiographic studies of the brain - MRI - CAT(CT)-Scan

Polyomaviridae

Detection of viral DNA using CSF as the sample (JC virus), urine, blood or biopsied material

Polyomaviridae

immunoperoxidase

Polyomaviridae

Probe hybridization of serum or tissue extracts

Parvoviridae

In situ hybridization of fixed tissue

Parvoviridae

Cell cultures using derived from epithelial cells (e.g., primary human embryonic kidney (HEK) cells, continuous [transformed] lines, such as HeLa, human epidermal carcinoma cells and KB)

Immunoassays (ELISA, FA using anti-hexon Ab on infected cells)

Adenoviridae

PCR using single primer pairs which target conserved segments that bracket hypervariable region in the heron gene

Adenoviridae

HemagglutinationInhibition (HI) and neutralization test (Nt)

Adenoviridae

measure type specific-Ag to identify specific serotypes

HemagglutinationInhibition (HI) and neutralization test (Nt)

Complementfixation (CF), HI, and Nt (most sensitive)

Adenoviridae

Enteropathogenic adenoviruses can be detected by:

-Directexamination of fecal extracts by electron microscopy -enzyme-linked immunosorbent assay - latex agglutination test

has terminal loops

Poxviridae

has low G + C content (30-40%) except for Parapoxvirus (63%)

Poxviridae

Proteins: Virions contain more than 100 polypeptides; many enzymes are present in core, including transcriptional system

Poxviridae

Envelope: Virion assembly involves formation of multiple membranes

Poxviridae

Poxvirus virions have two infectious forms

Mature virion -Enveloped virion

intracellular; dumbbell-shaped core wrapped with a single lipid membrane

Mature virion

extracellular; possesses an additional lipid membrane

Enveloped virion

• Largest most complex viruses; very resistant to inactivation

Poxviridae

was the first viral disease eradicated from the world

Smallpox

Orthopoxvirus

Variola Vaccinia Buffalopox Monkeypox Cowpox

Parapox

Orf Pseudocowpox Bovine papular stomatitis

Molluscipoxvirus

Molluscum contagiosum

Yatapoxvirus

Tanapox Yabapox

Primary Host: Humans

Variola Vaccinia Molluscum contagiosum

Primary Host: Water buffalo

Buffalopox

Primary Host: Rodents

Monkeypox

Primary Host: Sheep

Orf Pseudocowpox

Primary Host: Cows

Cowpox Bovine papular stomatitis

Primary Host: Monkeys

Monkeypox Tanapox Yabapox

Smallpox

Variola

Localized lesion; used for smallpox vaccination

Vaccinia

Human infections rare; localised lesion

Buffalopox Cowpox Orf Pseudocowpox Bovine papular stomatitis Tanapox

Human infections very rare and accidental; localised skin tutors

Yabapox

Human infections rare; generalised disease

Monkeypox

Many benign skin nodules

Molluscum contagiosum

Vesicular rash

Variola virus (Smallpox

cutaneous ulcerative lesions

Vaccinia virus (Cowpox)

a viremia which can metastasize into various organs and may cause death

vaccinia necrosum

— assoc, with 15- 40% mortality

Variola Major

— assoc, with 1% mortality

Variola Minor

Four Clinical Presentation of Variola Major

A. Mild B. Modified C. FIat D. Hemorrhagic

deep red hemorrhagic lesions

cowpox

occupational disease sheep and goat handlers

Orf virus

contagious pustular dermati or sore mouth infection

Orf virus

vesiculogranulomatous lesions on hands and face

Orf virus

contagious ecthyma, contagious pustular dermatitis or scabby mouth

Orf virus

derivative of vaccinia virus that has persisted in India

Buffalopox virus

are similar to smallpox

Monkeypox virus

are similar to cowpox

Buffalopox virus

Common method of examination to differentiate monkeypox from chickenpox and smallpox

presence of lymphadenopathy in the cervical, mandibular, and inguinal regions

benign epidermal tumor that occurs only in humans

Molluscum contagiosum

Envelope contains the glycoprotein HBsAg of three different size species with common C-termini, L-HBsAg (gp 42), M-HBsAg (gp 36), and S-HBsAg (9P 27)

Hepadnaviridae

Spherical

Hepadnaviridae Herpesviridae

•Core contains the phosphoprotein HBcAg, plus polymerase with three enzyme activities: reverse transcriptase, DNA polymerase, and RNase H

Hepadnaviridae

nudeocapsids, 18 nm

Hepadnaviridae

most abundant & basic constituent of non- infectious HBsAg particles

Small (S)

Virion: Dane particle

Hepadnaviridae

Non-infectious particles - composed of lipid and envelope proteins - spheres and filaments (22 nm, lengths up to 200 nm)

Hepadnaviridae

Hepadnaviridae • Negative DNA strand is [?] • Positive DNA strand is [?]

full length partially complete

• Genome encodes four ORF's

S C P X

encodes the envelope protein, S with three forms: L, M and S (HBsAg

encodes HBcAg and HBeAg proteins ("core")

encodes a polymerase with three functions

encodes a transactivating protein, HBx

First and second most common cause of acute viral hepatitis

1 HAV 2 HBV

Hepadna encodes several proteins

HBsAg [L, M, SI] HBe/HBc antigens

produce and release large amounts of HBsAg particles lacking genome can integrate into the host chromosome

HBV

Orthohepadnavirus

Hepatitis B virus Woodchuck hepatitis virus (WHV) Ground squirrel hepatitis

Avihepadna virus

Duck hepatitis B virus (DHBV)

Life Cycle of HBV

1. Attachment and HBV entry. 2. Release of viral nucleocapsid 3. Transport and release of rcDNA into nucleus 4. cccDNA formation/maintenance 5. HBV transcription 6. Translation of viral proteins 7. Encapsidation, reverse transcription and DNA synthesis 8. Maturation and release

serves as a stable template for transcription of viral mRNA

cccDNA

essential for HBV replication Associates with cccDNA

HBx protein

•Incubation Period: 40 to 180 days

HBV

Phases of HBV

1. Pre-icteric (Prodromal Phase) 2. Icteric 3. Convalescent

-dark urine (bilirubinuria) and closely followed by pale stools and jaundice

Icteric

- Uncommon but devastating outcome - Acute liver failure (can lead to death unless emergency liver transplantation is performed)

Fulminant hepatitis

undergo periodic reactivation

Herpesviridae

possess a large number of genes, some of which have proved to be susceptible to antiviral chemotherapy

Herpesviridae

Herpesviridae that commonly infect humans

HHV 1 to 8

•An amorphous, sometimes asymmetric structure between the capsid and envelope is designated the tegument

Herpesviridae

genomes possess terminal and internal repeated sequences

Herpesviridae

undergo genome rearrangements, giving rise to different genome "isomers''

HSVs

encode an array of virus-specific enzymes involved in nucleic acid metabolism, DNA synthesis, gene expression, and protein regulation

Herpesviruses

DNA polymerase, helicase- primase, thymidine kinase, transcription factors, protein kinases

Herpesviruses

Herpesviridae mechanism; sequential transcription and translation of:

immediate early (a), early (P), and late (y) genes

encode many enzymes (DNA polymerase) that promote viral DNA replication

Herpesviridae

establish latent infections

Herpesviridae

persits indefinitely in infected hosts

Herpesviridae

frequently reactivated in immunosuppressed hosts

Herpesviridae

some cause cancer

Herpesviridae

good targets for antiviral drugs

Herpesviridae

Encapsidation, Latent infection, DNA replication and capsid assembly site

nucleus

Enveloped virions accumulate in the ER and are released by

exocytosis cell lysis cell-to-cell bridges

intranuclear inclusions, cytomegalic cells or syncytia

Herpesviridae

Triggers virus replication and recurrent or intermittent shedding of virus, sometimes accompanied by recrudescence of clinical disease

Reactivation

immortalizing infections

Epstein-Barr virus

• Ubiquitous

Herpesviridae

• Cell-mediated immunity is required for control

Herpesviridae

Herpesviridae Transcription of the viral genome and viral protein synthesis proceeds in a coordinated and regulated manner in three phases:

1. Immediate early proteins (a) 2. Early proteins (p) 3. Late proteins (y)

consisting of proteins important for the regulation of gene transcription and takeover of the cell

1. Immediate early proteins (a)

consisting of more transcription factors and enzymes, including the DNA polymerase

2. Early proteins (p)

consisting mainly of structural proteins, which are generated after viral genome replication has begun

3. Late proteins (y)

Herpesviridae Taxonomic Classification

1. Alphaherpesviruses 2. Betaherpesviruses 3. Gammaherpesviridae

Interpretation of HBV Serologic Markers

Alphaherpesvirinae

Simplexvirus Varicellovirus

Betaherpesvirinae

Cytomegalovirus Roseotovirus

Gammaherpesvirinae

Lymphocrytovirus Rhadinovirus

Herpes simplex virus type 1 Herpes simplex virus type 2

Simplexvirus HHV 1 HHV 2

Human herpesvirus 6 Human herpesvirus 7

Roseotovirus HHV 6 HHV 7

Epstein-Barr virus

Lymphocrytovirus HHV 4

Kaposi sarcomaassociated virus

Rhadinovirus HHV 8

Cytomegalovirus

Cytomegalovirus HHV-5

Varicella-zoster virus

Varicellovirus HHV-3

Neurons Short, cytolytic

HHV1 HHV2 HHV3

Glands, kidneys Long, cytomegalic

HHV 5

Lymphoid tissue Long, lymphoproliferative

HHV 6 HHV 7

Lymphoid tissue Variable, lymphoproliferative

HHV 4 HHV 8

Gingivostomatitis Keratoconjunctivitis Encephalitis Genital disease Infections in newborns

HSV

(cold sores/ "fever blisters")

Herpes Labialis

Herpetic keratitis

Ocular Herpes

cutaneous herpes

Herpetic whitlow Herpes gladiatorum Eczema herpeticum

is an infection of the finger

Herpetic whitlow

is acquired by children with active eczema

Eczema herpeticum

is an infection of the body

Herpes gladiatorum

prevalent diagnosis in young adults with sore throats

Herpes pharyngitis

Cowdry type A acidophilic intranuclear inclusion bodies

HHV 1 HHV 2

syncytia formation

HSV

infects the innervating neuron, traveling by retrograde transport

HSV

for oral HSV

trigeminal ganglia

for genital HSV

sacral ganglia

are important to maintain HSV in latency

•CD8 T cells and IFN-y

contains infectious virions

vesicle fluid

is caused by a combination of viral pathology and immunopathology

Tissue damage

are required to kill infected cells and resolve acute disease

•T-helper 1 (THl)-associated and CD8 cytotoxic killer T-cell

•Antibody directed against the [?] of the virus neutralizes extracellular virus, limiting its spread, but is not sufficient to resolve the infection

glycoproteins

HSV infection is likely to recur and be more severe and may disseminate to the vital organs and the brain in it's absence

functional cell-mediated immunity

Triggers of HSV Recurrences

• Ultraviolet B radiation (skiing, tanning) • Fever (hence the name "fever blister") •Emotional stress (e.g., final examinations, big date) • Physical stress (irritation) • Menstruation • Foods: spicy, acidic, allergies • Immunosuppression

establishes latency in neurons

HSV

HSV is reactivated from latency by

stress or immune suppression

the only herpesvirus that is spread through the respiratory route

HHV 3

• Causes chickenpox

HHV 3

latent infection in neurons, specifically the dorsal root ganglia

HHV 3

shingles

HHV 3

Varicella

HHV 3

Herpes zoster ophthalmicus

HHV 3

Acute cerebellar ataxia

HHV 3

Highly contagious disease, one of the classic childhood exanthems

Varicella

encephalitis

Varicella

erythematous base dewdrop on a rose petal 2-4mm

Varicella

hallmark of Varicella

dewdrop on a rose petal

scabbed lesion appears— prevalent on trunk and head

Varicella