Micro - E4 Memorize Flashcards
Enveloped viruses
myxovirus
retrovirus
in vitro translation assay
( + ribosomes, tRNAs, aa, buffer, purified virus genome from virion)
“Are proteins made?” If yes, then…
picornavirus or retrovirus
in vitro enzyme assay
(+ NTPs, dNTPs, buffer (with host mRNAs, need these for 5’ caps), contents of lysed virions)
“Does the Virus come packaged with an enzyme that can polymerize nucleic acids?”
myxovirus
retrovirus
Transfection assay
Add the PURIFIED virus GENOME from virions
“Is the purified Virus GENOME infectious?”
papilloma
picorna
Oncogenic viruses
papilloma
retrovirus
Which virus encodes an RNA replicase
picornavirus
Which virus uses Vpg primer for genome replication
picornavirus
Which virus carries an RNA-dep RNAP (viral transcriptase)?
Myxovirus
Viral transcriptase goes to nucleus w/ genome
5’ caps stolen from host mRNA & used as primers
Virus with no 5’ cap or polyA tail
Myxovirus
HPV E6
Binds p53
How HPV prevents cell death by apoptosis
HPV E7
Binds Rb
How HPV stimulates entry into S-phase
Which viruses use differential splicing
papilloma virus
retrovirus
Events of HIV
adsorption penetration reverse transcription (synthesis of dsDNA) integration transcription+splicing translation assembly budding maturation via protease
Conditions which bacteriophage lambda undergoes lytic growth
RICH MEDIUM –> HIGH PROTEASE –> CII degraded–> phage undergoes LYTIC GROWTH
Conditions which bacteriophage lambda undergoes lysogeny
POOR MEDIUM –> LOW PROTEASE –-> CII activates Repressor Promoter –>Phage undergoes LYSOGENY
E. coli O157:H7
Late regulatory region of the phage carries Shiga-like toxin. Expression of the toxin genes, stx A and B, is greatly enhanced by the Q protein, expressed upon induction of the prophage.
Two component regulatory systems
The component that senses the environment is a membrane-bound sensor histidine kinase.
Phosphorylates a response regulator (2nd component of the two component system). controls the expression gene expression
MucA
MucA –> negative regulator of Au (sigma factor for alginate genes)
Lungs of CF patients accumulate mutant strains of P. aeruginosa that produce a truncated inactive MucA = mucoidy
Quorum sensing signaling compounds
Acylated homoserine lactones (Gram-negatives)
Short peptides (Gram-positives)
C. diff
\+, bacili obligate anaerobe TcdA, TcdA sx: intestinal disease spore forming Natural autotroph (complex nutritional requirements)
C. tetani
\+, bacilli obligate anaerobe neurotoxin --> CNS (GABA) spore forming sx: spastic paralysis (trismus - lockjaw, cant relax muscles)
C. botulinum
\+, bacilli obligate anaerobe neurotoxin --> PNS (ACh) sx: flaccid paralysis, can't stimulate muscles to contract spore forming
V. Cholera
-, comma shaped facultative anaerobe A-B toxin "rice water" diarrhea NON-spore forming
