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Flashcards in Exam 4 Deck (132):
1

Ellerman and Bang

in 1908, demonstrated that "filterable agents" can produce tumors in chickens

2

Rous

discovered that bacteria free filterable agents can cause sarcomas in chickens - Rous Sarcoma Virus

3

Bishop and Varmus

discovered the src gene of RSV is found in normal chicken DNA as a proto-oncogene

4

% of human cancers caused by viruses

20%

5

number of known human cancer causing viruses

6

6

name the 6 human cancer causing viruses

1. Hepatitis Virus B
2. Hepatitis Virus C
3. Human Papilloma Virus (HPV)
4. Epstein Barr Virus
5. Human Herpes Virus 8
6. Human T-lymphotrophic virus

7

Human papilloma virus can cause

cervical cancer

8

EBV can cause

Burkitt's Lymphoma

9

Human T-lymphotrophic Virus can cause

T cell lymphoma

10

5 steps to determine progression of cancer

1. Apoptosis override
2. Autonomy - don't require exogenous growth signals
3. immune escape
4. Angiogenesis
5. metastasis

11

# of retroviruses experimentally shown to induce cancer

2

12

retroviruses experimentally shown to induce cancer

1. Rous Sarcoma Virus
2. Mouse Mammary Virus

13

3 ways retroviruses can cause cancer

1. may carry a viral oncogene
2. may in-activate a tumor suppressor gene
3. may activate a cellular proto-oncogene

14

endogenous retroviruses

provirus virus integrated into genomic DNA

15

Shope

identified 1st DNA tumor viruses

16

Rabbit papilloma virus may have caused the - myth

jackalope

17

4 DNA tumor viruses

1. papilloma virus
2. EBV
3. Kaposi's Sarcoma
4.HBV

18

EBV can cause tumors in --- populations, such as --

immune suppressed, those with malaria or HIV-AIDS

19

process of EBV cancer induction

v-onc EBNA-2 inserts into c-myc, disrupting cell cycle reg and apoptosis, disruption leads to uncontrolled cell growth

20

Kaposi's sarcoma is a --

HHV-8 virus

21

Karposi's sarcoma is aggressive in ---

people with immune supression such as HIV AIDs

22

EBV v-onc

EBNA-2

23

EBNA-2 is a ---- that

v-onc in EBV that integrates into c-myc gene

24

HPV structure

small, non-enveloped, icosahedral

25

HPV genome

closed circular dsDNA

26

HPV genome replication takes place in the

nucleus

27

what HPV processes occur in the nucleus

replication, nucleocapsid formation, maturation

28

leading cause of cervical cancer?

HPV

29

malignant cervical cancer tumors contain

integrated HPV-16 DNA

30

number of HPV types

100

31

HPV risk types

low, intermediate, high

32

expression of HPV integrated gene products -- leads to ---

E6 and E7, lead to inactivation of tumor suppressors p53 and Rb

33

tumor suppressor genes inactivated by HPV integration

p53 and Rb

34

HPV E6 leads to

p53 degradation

35

HPV E7 leads to

cell cycle activation and proliferation

36

viruses that induce cancer in animals other than humans

adenoviruses and polyomaviruses

37

adenovirus that can induce tumors in hamsters

12

38

2 adenovirus v-oncs

E1A and E1B

39

SV-40 may have a role in -- by --

animal cancer, by binding and inactivating p53

40

SV-40 structure

small non-enveloped icosahedral

41

SV-40 genome

cc dsDNA

42

SV-40 -- may bind and inactivate p53

large and small T antigen

43

TSEs stands for

Transmissible Spongiform Encephalopathies

44

prions are exremely resistant to (4)

1. strong bases
2. high heat
3. high pressure
4. bleech

45

viroids are

plant pathogens

46

viriods are composed of

RNA

47

Griffith

1st hypothesized TSEs

48

Prion gene

PrP

49

2 PrP forms

PrP^c (normal) and PrP^Sc or res (infectious form)

50

Prusiner

isolated PrP

51

prion CFR

100%

52

1st clinically described TSE

Kuru

53

Kuru is found among

South Fore people of Papua New Guinea

54

Kuru passed by ritual of

endo-cannibalism

55

Kuru stages

1. Ambulent stage
2. Sedentary stage
3. Terminal stage

56

Kuru ambulent stage

tremors, imbalance, slurred speach, loss of coordination

57

Kuru sedentary stage

no longer walk, uncontrolled movement, waves of emotion

58

Kuru terminal stage

incontinence, difficulty swallowing, ulceration

59

PrP is encoded by the -- gene

PRNP

60

PRNP is gene is on c'some -

20

61

changes to --- of PrP may cause pathogenicity

Beta sheet domain

62

normal PrP is found in -- tissue and -- is prediceted to be important in --

neurological, copper metabolism

63

PrP^res is ---

resistant to degradation by lysosomes

64

3 possible origins of TSEs

infection
inheritance
sporadic formation

65

most common human TSE

Creutzfeldt-Jakob Disease

66

mode of CJD transmission

sporadic or inherited or diet

67

% of CJD that is sporadic

80%

68

inherited forms of CJD (3)

1. CJD
2. Gertsmann-Straussler-Scheinker syndrom
3. Fatal Familial Insomnia

69

varient CJD is aquired via

diet

70

CJD neuroinvasion occurs through the ---

vagus nerve to the brainstem

71

varient CJD early symtomology

memory loss
emotional instability

72

late varient CJD symptomology

neuromuscular degeneration
persistent vegetative state

73

following CJD onset, death occurs -

within one year

74

PrP causes spongiosis of brain tissue, due to -- and -- damaging tissue

PrPres plaques and astrocytosis

75

how did scrapie from sheep get to cows

scrapie infected offal fed to cows

76

BSE was 1st observed

England, 1980s

77

human cases of vCJD in england from BSE peaked in

1994

78

BSE mitigated by

surveilance and feed bans

79

chronic wasting disease 1st observed in

northern CO mule deer in the 1960s

80

CWD transmitted by

direct and indirect contact in feces and suliva

81

% white tail deer seropositive for CWD

25%

82

CWD to humans?

no reported cases

83

viroid genome

+sense cc ssRNA

84

viroid structure

rod like, 30nm

85

do viroids code for protein?

no

86

# of viroid species

over 40

87

Diener

discovered viroids in potatos

88

viroid 1st discovered in potatoes

potato spindle tuber viroid disease

89

2 viroid families

avsunviroidae and pospiviroidae

90

pospiviroidae structure

rod like

91

number of viroid structural/functional domains

5

92

viroid domain that determines replication

C

93

viroid domain that determines plant pathology

P

94

how do viroids propogate cell to cell

plasmodesmata

95

how to viriods synthesize genome?

host RNA pol

96

method of viroid rep

host RNA pol, rolling circle

97

what processes viroid RNA

viroid hammerhead ribozymes - catalyze cleavage and ligation, then circularized by host ligase

98

bacteriophages infect

bacteria and archaea

99

phages are the --

most abundant "form of life on earth"

100

number of phage particles estimate

10^31

101

first observed phages

Twort

102

discovered phages, used them in phage therapy

d'Herelle

103

phage morphology

binary - have a head and tail

104

most phages have -- genomes

dsDNA

105

MS2 structure

25nm diameter, no tail, 4 genes

106

T4 structure

has head and tail, head composed of 20 proteins
200nm, 200 genes

107

2 phage life cycles

lytic and lysogenic

108

most infectous phage stage

lytic

109

in lytic phage stage

phage replicated genome, makes new phage particles, releases from host

110

in lysogenic phage stage

genetic material integrates into the host genome, forming a prophage

111

what is a host called after lysogenic integration

lysogen

112

gene expression in phages

sequential, early, middle and late genes

113

T4 early stage

host like promoters on gene, recognized by RNAP II

114

T4 middle stage

promoters differ from host, expression requires early gene products that help RNAP II bind to pomoter

115

T4 early gene products that aid in promoter binding

AsiA and MotA

116

T4 late stage promoters

defective, require T4 encoded sigma factor for RNAP III recognition

117

another way for phage to control gene expression

encode own RNA pol

118

T7 encodes

its own RNA pol

119

main way for phages to escape host

lysis

120

to escape cell via lysis, phage must

destroy the peptidoglycan cell wall, using phage encoded endolysin

121

what happens upon prophage reactivation?

re-enters the lytic cycle - can happen in response to stress, damage, nutrient limitations

122

phage integration

site specific, done by homologous recombination at DNA sites on phage (attP) and bacteria (attB)

123

phage excision

done by phage encoded excisionase (Xis)

124

phage integration done by

phage encoded Integrase (Int)

125

phage integration occurs by

homologous recombination

126

lysogenic conversion is when

a phage alters the phenotype of a lysogen

127

Shiga toxin is made by

some e coli and shigella

128

Shiga toxin is an example of

lysogenic conversion

129

shiga toxin is encoded on

STX

130

STX expression occurs

during STX replication in response to stress

131

shiga toxin is release when the host

lyses

132

big issue about shiga toxin

STX carrying phage can infect normal e coli of gut, convert them to carryers, cause dysentery or hemolytic uremic syndrome