Trypanosomes

Question 1

Normally hap or diploid?

Answer 1

Diploid

Question 2

How many haploid chromosomes do the tri trips have

Answer 2

Brucei- 11
Cruzi- 41
Major- 36

Question 3

What is the closest free living relative of trips

Answer 3

Bodo saltans- has a larger genome

Question 4

Describe Polycistronic transcription units

Answer 4

Genes are arranged in clusters on a single strand and lack individual promoters

Question 5

How is mRNA produced in tryps

Answer 5

Trans splicing and polyadenylation of Polycistronic

Question 6

Where does rna pol 2 start and finish in tryps

Answer 6

Start Strand switch regions between two divergent ptus

End ssr between convergent ptus

Question 7

Similarities between trans and cis splicing

Answer 7

1) largely share the same mechanism- two consecutive catalytic trans esterification reactions
2) major components of the spliceosomes are conserved apart from poly a polymerase

Question 8

Differences in trans and cis splicing

Answer 8

CIs takes out intron trans dissects pcu

Question 9

Describe the general features of trypanosomes

5

Answer 9

1) unicellular parasites
2) both intra and extra cellular
3) complex life-cycles and multiple hosts
4) diverse disease syndromes and a global distribution
5) ancient and bio diverse

Question 10

Describe Polycistronic transcription units

3

Answer 10

• conserved through chromosomal rearrangements
• ancestral feature before parasitism
• sub telomeres regions are species specific and so likely represent adaptions for parasitism

Question 11

What is a ubiquitous feature of leishmania

Answer 11

Aneuploidy probably caused by chromosome replication errors

Question 12

Describe genomic variation in leishmania

3

Answer 12

• in asexual lineage in rapid response to environmental changes
• such as drug resistance- amplification of chromosome 31

Question 13

What do telomeres structures contain

Answer 13

Vsg and species specific genes

Question 14

Describe comparative genomics
Purpose
Limitations
Revealed

Answer 14

Purpose- define what is unique to identify the genetic causes of species specific phenotypes
Limitations- scope- analyses content not function
-scale- small changes missed
Revealed wide spread conservation of genome content and structure through tryp genomes
Most species specific genes are cell surface glycoproteins that probably have an immune selection pressure

Question 15

Describe amastin

3

Answer 15

Amastin is expressed by all trips although mainly in the intra cellular amastigote stage of leishmania.
Expressed on cell surface transmembrane glycoprotein
Since leishmania has parasitised vertebrates amastin has had a massive elaboration compared to its monoxenic cousins crithidia and leptomonas

Question 16

What genome structure do tryps have?

Answer 16

Polycistronic transcription units are highly conserved

Question 17

How are trypanosome and leishmania different and similar

Answer 17

Similar in content and organisation
Differ in features of the host-parasite interface e.g. Amastin
These compounds are the most dynamic parts of the genome

Question 18

When does most regulation occur in trips %

Answer 18

Transcriptomic-2-35%

Proteomic 40-50%

Question 19

What could comparative analysis show in terms of developmental variation in trips? + e.g.

Answer 19

• metabolic differences, species specific surface genes

- t. Vivax doesn’t enter midgut of the fly, they don’t express pyruvate metabolism in vertebrate stage

Question 20

What has genome sequencing allowed

Answer 20

Determine the genetic causes of drug resistance and therefore the mechanism

Question 21

Describe the sequence of reverse vaccinology

Answer 21

Parasite genome
Screen for likely antigens
Express recombinant protein
Demonstrate immunogenicity to serum
Demonstrate protective effect in vivo
Clinical trials

Question 22

What do antigens need to be to work?

5

Answer 22

Surface expressed
Infective/visible stage
Antibody epitope a
Structural consistency
Non-host

Question 23

Describe VSG diagnosis

Answer 23

Variant antigen profiling of T. congolense, VAP exploits sub divisions within the tryp repertoire to provide a metric of genomic variation between individuals