B2- T Brucei Intro Flashcards
WhT 2 types of Brunei are there
Gambiense and rhodesiense (zoonotic and chronic illness)
What arthropod vector
Tsetse fly
Which trypanosoma causes Chagas’ disease in South America
T cruzi
Where does t brucei live
Ec eg in blood or csf
Explain the life cycle from infection into human
Metacyclic form is injected from saliva which forms long and slender form with rapid binary fission
Then some switch to short and stumpy (not dividing) for transmission back to fly (more resistant)
Fly intakes short and stumpy and in gut will convert to pro cyclic form with binary fission which then travels to salivary glands and forms epimastigotes
sexually reproducing to make the metacyclic form taken up by humans
Which disease does it cause which is lethal
African trypanosomiasis
How do they survive since they induce a strong ab responses in blood
Evasion through changing surface coat happens every 7 days in random parasites
Explain the waves of parasite Mia
Every 7 days there is a drop in the peak where ab / adaptive has kicked in
Then evasion occurs
Which genus’s are closely related to t brucei (all kineroplastida)
Crithidia fasciculata - used because not parasitic
And leishmania
Which type of brucei causes more chronic illness
Rhodesiese
Since it’s diploid organism, how many chr pairs does it have e
11
What other chr do they have
100 mini and 5 intermediate
How many predicted vs specific genes
9000 fenes
1700 specific to them
Is this big compared to bacteria
Yes 35mb vs 5mb
Which rna pol 1 is usually for rrna but used for pcg like vsg in brucei
Rna pol 1
Where are these genes on chr
Subtelomeric regions (close to ends)
Why are most vsg pseudo genes (non functional eg with mutations in promoter)
Help to form mosaic genes by ectopic recombination
Why would blood borne parasites need lower metabolic capacity
Large amounts in blood
What % of all dna is kinetoppast
10-20%
Where is kinetoplast located
Base of flagella
What does compartmentalisation of nucleus mean
Diff compartments for replication of dna and also for transcription eg pol 1 activity in diff place to pol 2
How does pol 2 localisation differ to 1 and 3
1 has 1localised spot in Extranucleolar body and nucleolus
2 has poles (appears in poles)
3 is scattered around nucleus
What is the nuclelus for
Production of ribosomes
Pre rrna processing and 40/60s assembly
Where are rrna genes and rna pol 1 located
On periphery of the nucleolus
Which kinase needed for nucleolus organisation and what happens if disrupted
Tor1 kinase
If not there is dispersion of pol 1
What types of chromatin are in brucei nucleolus
Eu and hetero (also packaged with dense chromatin histone octamers)
How does chromatin differ to mammals
Loosely packed and chr don’t condense during mitosis
Is condensation different between different forms
Yes different In procyclic (insect form) and the blood stream form
Which proteins also contained at the periphery nucleolus
Nuclear function proteins
Like for rna pol 1 txn
Transcription EF (tfIIS)
NoLP proteins
How are Hi-C and pacbio linked together to study brucei
Hi-c chromatin capture allows to capture interactions between dna in the tertiary structure far away in primary
Cross link/freeze dna via formaldehyde
RE cutting
Ligation
Amplification by PCR
Pacbio long read single dna RT sequencing (not fragments like illumina)
What is the difference between the epimastigote forms and metacyclic
Metacyclic are infective
Why is it called sleeping sickness
Can enter the csf gaining access to the brain and causing lethargy, confusion, seizures, paralysis / dearh
In mammalian cells, our nuclei have chr territories where our chr will segregate in different areas of nucleus. Is this found in t brucei
No evidence yet
