L13- Viruses Flashcards
What can affect host varistions when infected with viruses
Their eg suscetibility of diseases eyc. Due to thr integration of viral genomes (virome)
How many copies of rv genomes do we have
30k aprox
What types of euk viruses are in hunab
Pathogenic, non pathogenic, fungal viruses, microbial parasitic viruses eg tvv
Are pahges or viruses more common
Phages as we have more bacterial cells
What is the lytic cycle
Whete phage particles are produced within bacterial crlls and xaude lysis when bud out
What is lysogenic cycle
Where the phage genome is integrated into bacterial genome forming a prophage.
What sort of HGT events ovcur in lysogenic
Virulence eg shiga toxin, antibiotic resistance, killing of competitors
What are the 2 fates of lysogenic phade
Keep replicating genome or enter lytic stage again
How does shiga toxin in ehec cause diarrhoea
Blocks host protein synthesis
What diseases is ehec related to
Harmorrhagic colitis , haemolytic uremia syndrome
Are phages weakly or highly ikmunogrnic
Weak. They form a low titre of neutralising ab but no inflammation (could be incolved in tolerance??)
What NA is extracted from phages
Both rna and dna because can have both thpes of phages
What is all na transferred to before sequencing
Cdna
Which srticle discusses metagenomics with phages
Lawrence et al 2019
How are phages isolated (lawrence 2019)
Using plaque assays where bscteria grown pn agar plates rhen isolate phages by looking st plaque forms
Do all phages form plaques
No = issue wjrh isolatikn
What are alternstive methofs eg for isolsting single cells
FACS - fluorescence activsted cell sorting
What is VLP and how does it allow isolation of phage NA
Birus like particle prep isolates bacteria from NA eg cia centrifugation
What 2 types of data teference programs are for phages
Both for integrated phages prophages and non integrated sequences too
What is an issue eith phage databases
Low diversity of reference genomes. 80% are caudovirales
Which phage was found to infeeqse in ibd patients whilst lower bacterial diversity
Caudovirales
What bactefia had positive correlation with caudoviralea in ibd
Prevotella
Which pathogenic microbiota increased in bacterial vaginosis / sysbiosis which had many prophages = link to disease
Gardnerella
Why are pahges known yo be modulstors of bacteria in bealth anr disease
Due to their promotion of bscterial genome envolution and colonisation of jew niches
