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
Whoch std virus has ds dna
HPV
What genome does HRV have (colds)
Ss rna
Sars cov also has ssrna. How is infleunza different
Its ss rna is setmented et for ag drift and shift
Why is nasal vaccine dev importwnt for things like hpv and covid
Provides eith 50% of igg and also siga
What forms the upper airways (nalt)
Nasal passages, sinuses, pharynx
What forms the fentral airways (balt)
Trachea, bronchi, bronchioles
What yupes of cells form mucus in central airways and which gorm cilia
Goblet cells and culiated cells fornremoval of mucus
What forms the lower airways Balt
Bronchioles
Alveolar ducts
Alveoli
Which immune crlls are v important in alveoli lumen , ie and ec
Macrophges
Which ig is formed in upper tract and airway cia m cells sampling
Siga
How does 50% of the igg against viral infection in lower resp tract get therr
Cia blood stream transudatuon and exudatuon methods (other 50% is local production)
Which viruses are common in upper tract
Rhino viruses (eg hrv) and staph aureus
Which are common in lower whete igg is
Infleunza, strep pneumoniae
Cha you use chemo with virus infections
No only bsctefial onfrctions
What id the main cold causing virus
Rhino viruses eg hrv.
Why is there no vaccine for rhjno viruses
100+ strains so cant be effective
Is hrv only in upper tract
No also in lower airways
What is the correlation between hrv and asthma
Hrv presence causes excessive inflammation, as well as the already excess allergic response causing epi barrier damage. This means hrv exacerbates/makes asthma worse
What sort of symtkms is linked to this
Problems with breathing
Give edamples of zoonotic viruses
Rabies
Ebola (bats)
Covid (bats)
Hiv 1- chimpanzees
Influenza A can be zoonotic eg bird. What is human to animal called
Zooanthroponosis
How many segmented ss rna does inflenza have
8 ssrna
What allows antigenic shift
Segment reassortment when 2 strains come together. Ag ha and na completely diff
What type of vaccine is rhe nasal vax for infleunza and what response
Live attenuated
Allows siga profuction and igg in airways
What is givrn to increase igg in resp tract for infleunza
Parentral subunit vaccine
Why is the efrectiveness of vsccine low
Ag shift and drift
What does rhe viral guy lung axis eventuslkt cause
Secondary bacterial infections/pneumonia (air sac/alveoli fill up)
What sort of cellular / environmental effects in lunts does ciruses cause
Ifn response increase Infreased mcuus build up Loss of cilia Epithelial damage Cytokine/pro inflam
What sort of bacterial changes seen in lungs after viral infection
Increase in proteobscteria eg H infleunza, increased firmicutes like s aureus, s. Pneumoniae
How do viruses impact gut
Affect microbiota eg increase in proteobscteria, h. Infleunza, bacteroidetes
reduction in firmicutes like sfb and lactobacillus whicu would form protection,
Eg lactobscillus sctivates dc which then activate nk
How does gut microbiota affect lung after viral infection
Lowers macrophages/neurrophils (eg by drcreasing sfb)
Also reduces other inflam cells
This also eventuallt allows secondary bacterial pneumonia
