Publication Date

2014

Document Type

Honors Thesis

Department

Biological Sciences

Keywords

Filariasis-Prevention, Elephantiasis-Prevention, Sesquiterpene lactones, Nematodes-Genetics, Parasite antigens, Natural products, Brugia pahangi, Brugia malayi, Lymphatic filariasis, Elephantiasis, Drug discovery, Neurolama lobata

Abstract

Lymphatic filariasis (LF) is a neglected tropical disease currently afflicting over 125 million people in 73 countries (GAELF). Among others, a major issue barring the success of the World Health Organization's efforts to eradicate LF is emerging genetic resistance of the parasites to antifilarial medications. These issues may be alleviated through the development of novel antifilarial drugs from bioactive secondary metabolites from plants (Murthy, Joseph, and Murthy 2011). Two sesquiterpene lactones, Neurolenin A and Neurolenin B, from the Central American shrub weed Neurolaena lobata, are tested for bioactivity against the filarial nematode Brugia pahangi. Tests for in vitro mortality of Neurolenin A, Neurolenin B, and 1:1 Neurolenin A+B against adult male, adult female, and larval stage 3 (L3) B.pahangi are performed (doses: 0.6 μg/mL, 0.5 μg/mL, and 0.4 μg/mL). RNA-seq is also performed on mRNA from adult female B. pahangi treated either with crude ethanolic N. lobata extract (300 μg/mL) (n=45), Neurolenin B (0.5 μg/mL) (n=45), or nothing (negative control) (n=45) to begin elucidating the role of differential gene expression in the mechanism of action for N. lobata and Neurolenin B. A bioinformatics workflow is also developed for analysis of RNA-seq data. Neurolenin A is not significantly bioactive against all tested B. pahangi in an in vitro toxicity test of 80 hours. However, Neurolenin B and 1:1 Neurolenin mix are bioactive against B. pahangi. Neurolenin B and 1:1 Neurolenin A+B are shown to interrupt the L3-to-L4 molt. RNAseq confirms that gene expression changes significantly as the worms die (p<0.05), indicating that N. lobata may interrupt the biology of B. pahangi at the gene expression level. The bioinformatics pipeline established for the analysis of this data is able to detect global changes in gene expression in adult female B. pahangi over time.

Language

English

Comments

vi, 114 pages : color illustrations. Honors Project-Smith College, 2014. Includes bibliographical references (pages 111-114)

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