Lecture 7 Flashcards
What is IBD
-inclusion body disease
-infectusous disease of snakes recognized since the mid 70’s
-best characterized in boas and pythons
-can be transmitted from snake to snake
what are the symptoms of IBD
-neurological symptoms: stargazing and tie up un knots
-anorexis, refusal to eat and/or regurgitation
-withering
-Progressive and fatal
what are inclusion bodies^
-intracytoplasmic aggregates of stainable substances, usually proteins
-can be sites of viral replication or hallmarks of genetic diseases like Parkinsons
what is the virochip?
-DNA microarray
-probes ofr every virus discovered to date
highly conserve regions
22 000 viral sequences
-in 2003 Joe used virochip to identify SARS as the source of the outbreak in <24h
What is the assemblathon?
A collaborative, reccuring effort to spur improvements in computational methods for genome assemble
what were the 2 viruses that the people found in the snakes?
-annulated tree boas: CASV
-boa constrictors: GGV
what was used to validate the assemblies/gnomes of the snake virus
PCR, RACE and sanger sequencing
The viruses in the snakes were related to which type of virus?
arenavirus
What are arenaviruses
-bipartite ambisense ssrna
-previously believed to only infect mammals
-rodents are thought to be the natural reservoir
infection is typically chronic and asymptomatic in rodents
when they infect humans, they can cause severe disease ex: Lassa virus (LASV): fatal hemorrhagic fever in humans
Why are CASV and GGV look like arenaviruses?
-bisegmented ambisense genome orientation
-2 opposite sense ORFs
-intergenic regions on both segments are predicted hairpin structures
-terminal 19-nt at the 5’ and 3’ ends are reverse complements
-17-19% similarities to LCMV, LASV and TCRV
True or false: the CASV and GGV glycoproteins look like arenavirus GPs
FALSE
-a protein blast search revealed that the CASV and GGV glycoproteins did not look like arenavirus GPs
-instead they looked like GPs from filovirus like ebola and marbug (99% identity of predicted fusion domain to ebola sudan GP)
-this suggests that filoviruses and reptile arenaviruses share a common ancestor
how did they study the snake viruses in the lab
In vitro virus culture (inoculate cells with virus harvested from infected snakes) - Reptile cell lines (viper and iguana heart) = No growth ☹
- Monkey kidney cell line (Vero cells) = No growth ☹
Harvested tissue from a female boa constrictor (“Juliet”) who died of lymphoma
- Attempted to create continuous cell lines
- Of the multiple tissues and conditions attempted, cell proliferation was only evident in a culture of adherent cells from Juliet’s kidneys (JK cells)
true or false: CASV NP proteins localize to inclusion bodies in infected tissues
true
The DerRisi lab used a … approach to identify a possible source for snake IBD
The DerRisi lab used a metagenomic approach to identify a possible viral source for snake IBD
- Virochip (DNA microarray)
- RNA-sequencing (Next Generation Sequencing)
- Bioinformatics (Boa constrictor genome assembly and identification of viral sequences)
How did the lab detect the viruses on snake tissues?
Detected in infected snake tissues and cells using qRT-PCR,
Western blot and immunofluorescence analysis
