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76 Cards in this Set

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Who discovered the 1st cancer causing virus?

Peyton Rous (rous sarcoma virus)

What are the 6 viruses known to cause cancer?

Hep B, Hep C, HPV, Epstein-Barr, Kaposi's Sarcoma-Associated Herpesvirus, and Human T-lymphotropic virus

Which DNA tumor virus was discovered by Richard Shope and he observed tumors on rabbits?

Rabbit Fibroma

How do DNA tumor viruses differ from RNA tumor viruses?

Structure, genome organization/replication strategies, and oncogenes of DNA tumor viruses are essential viral genes in replication.

Which DNA tumor virus is small, icosahedral symmetry, no envelope, over 100 serotypes, (2 cause cancer), and has a circular double stranded genome?

Human Papillomavirus

How does HPV replicate?

In nucleus of metabolically active basal epithelial cells of skin.

Which 2 HPV serotypes cause cancer?

16 & 18

How is HPV detected?

PCR, sequence analysis for serotype determination

What is the supposed co-factor with HPV for cervical cancer?

HSV-2 because of the recurrent inflammation it brings due to genital herpes.

Which herpes virus causes Burkitt's lymphoma?

Epstein Barr virus

Which cancer virus is associated with chromosomal translocation of the c-myc oncogene from 8 to 14?

Epstein Barr

What condition other than Burkitt's Lymphoma is caused by Epstein Barr virus?

Nasopharyngeal Carcinoma

Which cancer causing virus is due to human herpes virus 8?

Kaposi's Sarcoma

Who are at most risk for developing Kaposi's sarcoma?

Elderly men in of Mediterranean/Middle East and 50% of homosexual men.

Which cancer causing virus causes hepatocellular carcinoma?

Hep B Virus

Which vaccine is the 1st to prevent cancer?

Hep B vaccine

Can Hep C cause hepatocellular carcinoma?

Yes but from a different mechanism than Hep B

What are the 3 main protein groups of RNA tumor virues?

Gag (capsid), Pol (reverse transcriptase), Env (envelope)

How do RNA tumor viruses replicate?

Attachment of envelope to receptor. Membrane fusion/entry. Uncoating. Reverse transcription causes RNA to double stranded DNA and it enters the cell nucleus. DNA inserted into host chromosome. Transcription of viral genes/oncogenes.

How can a virus accidentally pick up a proto-oncogene?

1. provirus disintegrates from host chromosome & bring neighboring cell gene along


2. Mistakes during transcription


3. Progeny retrovirus include v-onc gene

Which retrovirus is endemic in japan/south america/Caribbean, infects CD-4 lymphocytes, and is transmitted via breast milk, placenta, or female to male sexual contact?

HTLV-1

Which disease caused by HTLV-1 is a cancer of the CD4 T-lymphocytes caused by viral tax proteins activating cellular interleukin 2 which causes abnormal cell growth and usually death?

Adult T-cell Leukemia

Which retrovirus is found in a lot of the human genome but hasn't been proven to cause cancer due to defective viral sequences?

Human Endogenous Retrovirus

What virus has been associated with obesity?

Human Adenovirus 36

Which virus is icosahedral, enveloped (has spikes), 2 copies of ssRNA (+) genome, has tRNAs that bind to each copy and act as reverse transcriptase, and has several accessory genes?

HIV

How is HIV a weird RNA virus?

Includes replication in the cell nucleus

What cells does HIV infect?

CD4 (lyses too), CD8, macrophages, natural killer cells, nervous system cells, and dendritic cells.

What are the major receptors and co-receptors that enable HIV attachment?

Major: CD4 & Macrophages


Co: CXCR4 & CCR5

What structure allows for the conformational changes which causes co-receptors to anchor the virus into membrane and pulls in for fusion?

gp120 & gp41 spikes

What serves as a primer and initiates DNA synthesis for HIV?

tRNAs

What is the final product of DNA synthesis?

dsDNA flanked by long terminal repeat sequences

What integrates the HIV viral genome into the host cell's DNA?

integrase protein (p32)

In HIV-1 what is proviral DNA transcribed from?


What is it transcribed into and by what?

a single promoter in 5' LTR


viral RNA by RNA Pol 3

How are HIV-1 viral particles assembled and released?

They are assembled at budding sites at the plasma membrane--> gag and pol proteins are cleaved to form mature virus particle. Released by budding.

What are the 3 phases of infection by HIV-1?

1. Primary HIV-1 infection


2. Chronic asymptomatic phase


3. Clinical AIDS

How is HIV diagnosed?

ELISA test that is confirmed with Western Blot.

How is HIV-1 managed?

CD4 T lymphocyte counts & virus-load monitoring

What are the common antivirals for HIV?

Zidovudine (some resistance has emerged)


Highly Active Retroviral Therapy uses 3 compounds at least at the same time (generally effective)

what are the 5 classes of HIV antiviral therapy?

1. Non-nucleoside/nucloside reverse trancriptase inhibitors


2. Protease Inhibitors


3. Fusion Inhibitors


4. Integrase inhibitors


5. CCR5 Blocking Inhibitor

What are the 3 distinct groups of HIV?

M (major), O (outlier), and N (nev)

What is the difference between HIV-2 and HIV-1?

Typically less pathogenic, found more in Central Africa, and is rare in the U.S.

Some people seem to be born with resistance to HIV. Which gene is this associated with?

CCR5 gene is missing 32 base pairs so it creates a truncated protein that isn't detectable in cell's surface so HIV can't attach

What type of virus causes Marburg and Ebola Viruses?

Filoviruses

What is the Marburg virus?

First encountered in 1967. Workers unknowingly exposed to infected chimps. Caused a hemorrhagic fever.

What are the 5 strains of the Ebola virus?

Zaire, Sudan, Bundibungyo, Tai Forrest, Reston

Which is the only deadly Ebola strain in humans?

Zaire

How does Ebola infect the body?

Attacks/infects dendritic cells and monocytes causing them to secrete cytokines--> cytokine storm causing fever, increase vascular permeability, rash, hemorrhage, liver infection, multiple organ failure, and immune system collapse.

What are the initial symptoms and symptoms of acute disease?

I: headache, fever, sore throat, muscle aches


A: vomiting, diarrhea, skin rash, and internal bleeding

What treatments are given to Ebola patients?

Supporting care. ZMapp is an experimental antiviral.

Which slow virus causes progressive mutlifocal leukoencephalopothy?

JC papovavirus

What is progressive mutlifocal leukoencephalopothy?

Found in immunosuppressed/AIDS patients. Infect oligodendrocytes. Presents with confusion, dementia, altered speech/vision, loss of coordination, no inflammation, paralysis and death.

Which slow virus disease is caused by the measles virus and causes gradual personality/behavioral/intellectual changes, mocyclical jerks, spasticity, blindness & death?

Subacute Sclerosing Panencephalitis

What prion disease was studied by Dr. Gadjusek in New Guinea?

Kuru

What are the 3 stages of Kuru?

1. Ambulant: unsteady gait/voice/hands/eyes, tremors/shivering, slurred speech, loss of coordination.


2. Sedentary: can't walk w/o support, higher severity tremors, laughter outbursts, depression/mental slowing


3. Terminal: can't sit w/o help, incontinence, difficulty swallowing, death

Which prion disease has symptoms of progressive atxia, tremors, severe itching, and death and causes rod-like fibers in the brain tissue?

Scrapie

Which prion disease has an incubation period upward of 30 years, presents as personality changes, decrease intellectual abilities, vision problems, myoclonal jerks, ataxia, & death within 9 months?

Creutzfeldt-Jakob Disease

How is CJD diagnosed?

Clinical signs and EEG abnormalities.

Which prion disease presents as unsteady gait, aggressiveness, issues getting up/down, itching, anorexia, excessive licking, and spans 2-6 months before death?

Mad Cow Disease

Which prion disease causes its target animal to exhibit dramatic weight loss, blank expression, excessive drooling/thirst, sluggish behavior, isolation, and poor coats?

Chronic Wasting Disease

What type of virus was discovered by Martinus Beijenicnk?

Plant viruses (tobacco mosaic precisely)

How does infection via plant cells vary from animal?

Plant cells have to typically be wounded before they can be infected

Contrast vertical and horizontal transfer?

H: plant to plant


V: parent to offspring

How are viruses transmitted via soil?

They're present in soil which acts as an abrasive and infect via wind/rain action or through damaged roots

What are the symptoms of a plant virus?

Dwarfing, leaf curling, reduced yield, fruit distortion, chlorosis, color deviations/mosaic patterns/rings, wilting/withering, necrosis, & bark scaling.

How are plant viruses diagnosed?

electron microscopy, inclusion bodies, cell culture, ELISA for viral antigens, DNA/RNA probes

How to plant viruses appear morphologically?

1. long, helical flexuous


2. rigid helical


3. short


ALL are rods, all naked

What are the major genome types of plant viruses?

+ ssRNA, dsRNA, ssDNA, and dsDNA

What are the disadvantages of a segmented genome?

all segments need their own particle & single cell has to take all of those up or it won't produce an infection.

Due to lack of lysis what happens once a plant is infected with a virus?

It is forever infected

What virus infects tobacco, is the most studied, has a wide variety of hosts, is helical, no envelope, ssRNA (+), is very stable, and self-assembles?

Tobacco Mosaic virus

How does tobacco mosaic virus replicate?

Has replication complexes that increase in size on the ER in association with the cytoskeleton so it can move through the cell via plasmodesmata.


What are the symptoms of tobacco mosaic virus?

light green color between veins, mosaic pattern, dead leaves, and stunted plants

What is tobacco mosaic virus's host range and transmission mechanism?

can infect up to 500 flowering plants (peppers, tobacco, tomatoes, and potatoes mainly). Mainly spread crop to crop via mechanical mechanism. Cigarettes/cigars can also contribute.

Which cassava virus is ssDNA, only in africa, transmitted via white fly, most damaging, and causes leaf mosaic chlorosis/leaf distortion/stunting?

Cassava Mosaic

Which cassava virus is + ssRNA, filamentous, in africa but causes severe chlorosis/necrosis of leaves and brown streaks on stems, and causes the cassava to become inedible?

Cassava Brownstreak

Which plant virus occurs in citrus, is +ssRNA, transferred via aphids/grafting and presents as defoliation, small/poor fruit, stunting, decline/death, and is caused by starvation of the roots?

Citrus Tristeza Virus