USE OF MICROARRAY HYBRIDIZATION TO IDENTIFY BRUGIA GENES INVOLVED IN MOSQUITO INFECTIVITY
File(s)
Date
2009-05Author
Griffiths, Kathryn Greer
Advisor(s)
Michalski, Michelle
Metadata
Show full item recordAbstract
Filarial nematodes are a family of insect-borne parasitic worms that cause a
number of diseases in man and animals. The most widespread filarial disease of humans
is lymphatic filariasis, caused by worms in the genera Wuchereria and Brugia. Lymphatic
filariasis is an economic and social burden in endemic countries and affects
approximately 119 million people worldwide. Brugia malayi and B. pahangi
microfilariae (mf) require a maturation period of at least five days in the mammalian host
before they can infect mosquito vectors. This maturation process correlates with changes
in the surface composition of mf that likely are associated with changes in gene
expression. To test this hypothesis, we verified the differential infectivity of immature
(<3 day) and mature (>30 day) Brugia mf for black-eyed Liverpool strain of Aedes
aegypti (LVP), and then assessed transcriptome changes associated with microfilarial
maturation by competitively hybridizing microfilarial cDNAs to the B. malayi
oligonucleotide microarray. We identified transcripts that were more abundant in
immature (94 in B. pahangi and 29 in B. malayi) and mature (64 in B. pahangi and 14 in
B. malayi) mf. In each case, >40% of Brugia transcripts shared no similarity to known
genes, or were similar to genes with unknown function; the remaining transcripts were
categorized by putative function based on sequence similarity to known genes/proteins.
Microfilarial maturation was not associated with demonstrable changes in the abundance
of transmembrane or secreted proteins; however, differences in transcript abundance
were observed for many that have predicted functions. For example, immature mf were
enriched for transcripts putatively associated with immune modulation,
neurotransmission, transcription and cellular cytoskeleton elements. In mature mf, there
was an increase in transcripts potentially encoding hypodermal/muscle and surface
molecules, i.e., cuticular collagens and sheath components. These finding lend support to
the underlying hypothesis that changes in microfilarial gene expression drive surface
modifications that influence the parasite to begin development in compatible vectors.
Brugia malayi genes corresponding to differentially abundant transcripts were identified,
and transcript abundance validated by quantitative polymerase chain reaction. These
studies serve as a starting point towards gaining a better understanding of the parasite
side of the intricate parasite/mosquito relationship.
Subject
Nematoda Genetic aspects
Filarial worms Molecular genetics
Brugia pahangi
Brugia malayi
Mosquitoes Pathogens
Mosquitoes as carriers of diseases
Permanent Link
http://digital.library.wisc.edu/1793/46744Description
A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science-Biology Microbiology