Download Tsetse-Wolbchia symbiosis: Comes of age and has

Preventing the spread of infectious diseases
through the endosymbiotic relationships
with Wolbachia
BAMA ARTICLE ASSIGNMENT
7/30/13
By Lois Crozier
BAMA Teacher
Johnsonburg Area School District, Johnsonburg, PA
Article:
TSETSE-WOLBCHIA SYMBIOSIS: COMES
OF AGE AND HAS GREAT POTENTIAL
FOR PEST AND DISEASE CONTROL
Doudoumis, V., Alma, U., Askoy, E., Abd-Alla, A. M. M., Tsiamis, G., Brelsfoard, C.,
Aksoy, S., & Bourtzis, K. (2013). Tsetse-wolbachia symbiosis: Comes of age and has
great potential for pest and disease control. Journal of Invertebrate Pathology, 112,
S94-S103. doi: PMID: 22835476
Tsetse fly
ORDER: DIPTERA
FAMILY: GLOSSINIDAE
GENUS: GLOSSINA
Vector in the transmission of Trypanosomiasis
the cause of African Sleeping Sickness
MICROFILARIAE ! WHAT ARE THEY?
thread-like parasitic nematodes (roundworms)
transmitted by arthropod vectors
 microfilariae infect vector arthropods, in which
they mature to larvae
 adult worms inhabit specific tissues where they
mate and produce microfilariae, thread-like
larvae.

Tsetse fly
carries
flagellate
to host
animal
other then
a human
human
African Animal
Trypanosomiasis
(AAT)
Human African
Trypanosomiasis
(HAT)
THE COST OF TRYPANOSOMIASIS

60 million people live in regions where the
parasite is located.

African Animal Trypanosomiasis is the biggest
problem in preventing the increase of livestock
populations

African Animal Trypanosomiasis is the
leading cause of hunger and poverty
THE POINT?
 Current
vector control is not sustainable or
environmentally friendly.

Urgent need for pesticide free, environmentally
friendly method of vector control
Filarial Nematodes and Wolbachia
Mutualistic relationship with Filarial nematodes
Plays a role in nematode survival and reproduction.
Reproductive
parasitic
relationship with
Tsetse flies
Vector:
Tsetse fly is the
host for each of
these parasites
parasite:
Trypanosoma
brucei gambiens
parasite:
Trypanosoma
brucei
rhodesiense
Parasite:
Trypanosoma cruzi
African Sleeping
Sickness
http://www.rochester.edu/college/bio/labs/WerrenLab/WerrenLab-WolbachiaBiology.html
http://www.who.int/mediacentre/factsheets/fs259/en/
http://emedicine.medscape.com/article/214581-overview
Chagas Disease
3 SYMBIOTIC BACTERIA IN THE TSETSE FLY
1. Wigglesworth glossinidia
Found in 2 distinct populations in the insect:
Intracellular population in the specialized epithelial cells in the end gut
Plays a role in providing essential vitamins and minerals absent from a blood diet
Extracellular population in female milk secretion
Method of transmission to the intrauterine larvae through mothers milk.
An absence of Wigglesworth g. results in female sterility
Wigglesworth is heterozygous in the natural population
influences host juvenile larvae development of immune system
2.Sodalis glossinidius
Present in all lab populations and heterozygous in natural populations
Distributed in many tissues including haemolymph, salivary gland, milk gland,
an midgut where it lives close to where trypanosomes develop.
Passed to intrauterine larva through mothers milk
3.
Wolbachia pipiens
Obligatory

endosymbiont
(lives within the organism and either the endosymbiont or the
host cannot survive without the other)
maternally
transmitted
Found in reproductive tissue of insect
EFFECTS OF WOLBACHIA PIPIENS IN HOST
Parthenogenesis
( female reproduction
without fertilization )
Feminization ( male killing, male zygotes
don’t survive )
Incompatibility (CI)
 Most common
 Can be unidirectional or bidirectional
 Results in a reduction in the population
of the host
Cytoplasmic
ANOTHER METHOD TO STOP TRANSMISSION
Incompatible Insect Technique (IIT)
IIT causes sterility due to the presence of a
Wolbachia strain genetically capable of inducing
cytoplasmic incompatibility.
IIT
Has been done successfully in the lab and
in the field
INCOMPATIBLE INSECT TECHNIQUE (IIT)


Wolbachia-induced CI can control populations
of agricultural pests and disease vectors
might someday play a role in spreading or
replacing desired phenotypes
(because infected females have a reproductive advantage of passing their DNA onto the offspring )
 Methods
for inducing the transfer of desired genes have
yet to be worked out fully.
INFECTED
UNINFECTED
WITH
WOLBACHIA
WITH
WOLBACHIA
OFFSPRING
No
Yes
Yes
Yes
Yes
Higher
frequency
in the
Population
Proportional
to
the number
of
infected males
GLOSSINIA

WOLBACHIA
vector genus of tsetse flies is Glossinia


AND
http://www.who.int/mediacentre/factsheets/fs259/en/
Using 16S rRNA based PCR analysis
 3,750
flies from 12 species from 10 African
countries were tested
 Found multiple cytoplasmic strains and
Wolbachia gene insertions on the Glossinia
chromosomes ( host DNA)
HORIZONTAL GENE TRANSFER AND
WOLBACHIA
3 Wolbachia genes were found on the host DNA of
Glossinia m. morsitans
in natural and lab populations
1.
2.
3.
16S rRNA (used in classifying and identifying bacterial species)
fbpA (ferric iron binding protein-encoding gene or fibronetin binding protein)
wsp (Wolbachia surface protein)
Whole Genome Sequence of Glossinia m.morsitans
led to the identification of
at least 2 horizontal gene transfer events
52% of Wolbachia genome
transferred in one event
and
47% of Wolbachia genome being transferred in the
other event.
POSSIBILITIES AND HOPE

The HGT of Wolbachia genome can provide
clues into the evolution and transfer of
endosymbiont genes into multicellular
organisms

aiding in the development of Wolbachia as a
transport device to get desired genes into
vectors such as the tsetse fly to stop the
spread of African Trypanosomiasis and other
diseases spread by insects.
DISEASES
disease produced by a filarial worm depends
on the tissue locations preferred by adults and
type of microfilariae
 lymphatic filariasis

 disease
is caused by the presence of worms in the
regional lymphatic vessels
 and by the host response to the worms and worm
products
OTHER FILARIAL NEMATODE INFECTIONS

Elephantiasis of leg caused by chronic infection with the
filarial nematode Wuchereria bancrofti spread by a
mosquito vector

Onchocerca volvulus is a filarial worm that is
transmitted to humans by blackflies.



Mature worms live in the subcutaneous tissues and produce
microfilariae that migrate through the skin and connective
tissues.
do not move through the circulatory system
3-4 months after infection, form nodules on outer layer of
connective tissue which turns into calcifications
SUMMARY

HAT and AAT are serious problems in Africa and in North
America someday, as climates change.

Insecticides are not environmentally responsible or
sustainable, neither are baiting or releasing sterilized male
tsetse flies.

Wolbachia has the potential to rid the world of this sickness
and others, one fly at a time, one generation at a time.
Wouldn’t that be nice.
What is 16s rRNA?

16S ribosomal RNA is a component of prokaryotic
ribosomes having 1,542 nucleotides

used in reconstructing phylogenies

multiple sequences of 16S rRNA can exist within a
single bacterium
16S RRNA (CONTINUED)

Carl R.Woese , an American microbiologist and
biophysicist along with George E. Fox, a researcher at
the University of Houston, were well known for their
defining work in identifying a new domain in
classifying organisms, Archaea.
 by
phylogenetic taxonomy of 16S rRNA stemming
from their introduction of the lowest common
ancestor (a progenote).
 comparative analysis of ribosomal RNA

which they believed was the earliest genetic resemblance to life on
Earth today.
PCR applications of 16S rRNA

highly conservative primer binding sites making PCR
easier ( very few differences in primer sites for the gene)

Has hyper variable regions in its gene sequence making
gene sequences making it a very species specific tool
used to classify bacteria

Used in medical microbiology due to it being fast and
inexpensive, compared to using phenotypes to identify
bacteria

Originally used to classify bacteria now used to identify
new species of bacteria
http://en.wikipedia.org
BACK