|
James
B. Lok, Ph.D.
Professor of Parasitology, Dept of Pathobiology
Microbiology, Virology, and Parasitology Program
Address
Department of Pathobiology
430 Rosenthal Building
School of Veterinary Medicine
University of Pennsylvania
3800 Spruce Street
Philadelphia, PA 19104-6008
Office tel.: 215-898-7892
Lab tel.: 215-573-4756
Fax: 215-573-7023
E-mail: jlok@vet.upenn.edu
Link(s)
Dr. Lok's Veterinary School Faculty Page
Education
University of Southern Mississippi: BS (Biology), 1975.
Cornell University: MS (Entomology), 1979.
Cornell University: PhD (Entomology), 1981.
|
Research
Interests
- Molecular control of infective larval development in parasitic
nematodes.
- Sensory and neuronal regulation of the infective process
in parasitic nematodes.
- Molecular signaling between parasites and their hosts.
- Seasonality of filarial transmission and anti-filarial
chemotherapy
Key words: Strongyloides, Caenorhabditis,
Dirofilaria, transcription factor, dauer, G protein,
TGF beta, parasite, nematode.
Search PubMed for articles
Description
of Research
The Lok lab's primary interest is the endogenous
mechanism governing developmental arrest and lifespan in parasitic
nematodes. In the free-living nematode Caenorhabditis
elegans, output from an insulin/IGF-like signal transduction
pathway is critical to both these factors. We are currently
using the intestinal parasite Strongyloides stercoralis
to test the hypothesis that insulin signaling also regulates
arrest and reactivation of infective, autoinfective and hypobiotic
third-stage larvae, as well as lifespan in these chronic latent
stages of parasitic nematodes. In beginning to test this hypothesis
we have determined that genes encoding key elements of the
C. elegans insulin/IGF pathway are conserved in S.
stercoralis. We are now using C. elegans as
a genetic surrogate to assess function of Strongyloides
ilrk-1 and fktf-1, orthologs of the insulin
receptor and forkhead transcription factor, respectively in
the C. elegans insulin pathway. Specifically we are
asking whether these genes can complement loss-of-function
mutations in their orthologs when expressed in C. elegans
as heterologous transgenes. In addition to our work with insulin-like
signaling, we have also determined that elements of two other
signal transduction pathways that regulate dauer development
in C. elegans, a G protein-mediated odorant receptor
pathway and a TGF-β-like signal pathway, are also conserved
in S. stercoralis. In addition to our work on the
molecular and developmental biology of S. stercoralis,
we maintain an interest in the biology of Dirofilaria
immitis and in clinical management of canine and feline
heartworm disease.
Recent
Publications
Massey, HC Jr, Nishi M, Chaudhary K, Pakpour N and Lok JB. Structure and developmental expression of trongyloides stercoralisfktf-1, an ortholog of daf-16in Caenorhabditis elegans, a gene encoding a forkhead transcription factor necessary for dauer arrest. International Journal for Parasitology 2003; 33:1537-44.
Massey HC, Jr, Castelletto ML, Bhopale VM, Schad G A, Lok JB. Sst-tgh-1 from Strongyloides stercoralis encodes a proposed ortholog of daf-7 in Caenorhabditis elegans. Molecular and Biochemical Parasitology 2005; 142: 116-120.
Massey HC, Bhopale MK, Li X, Castelletto M, Lok JB. The fork head transcription factor FKTF-1b from Strongyloides stercoralis restores DAF-16 developmental function to mutant Caenorhabditis elegans. Journal for Parasitology 2006; 36: 347-352.
Li X, Massey HC, Nolan TJ, Schad GA, Kraus K, Sundaram M, Lok JB. Successful transgenesis of the parasitic nematode Strongyloides stercoralis requires endogenous non-coding control elements. International Journal for Parasitology 2006; 36: 671-679.
Ashton, F.T, Zhu, X., Boston, R., Lok, J.B., Schad, G.A. Strongyloides stercoralis:amphidial neuron pair ASJ triggers significant resumption of development by infective larvae of under host-mimicking in vitro conditions. Experimental Parasitology 2007; 115:92–97.
Lab
Rotation
Projects
- Mobilizing transposable elements in the genome
of Strongyloides stercoralis
- Mechanisms of transgene inheritance and
silencing in Strongyloides stercoralis
- Structure and function of an insulin/IGF-class
receptor kinase in Strongyloides stercoralis
- Structure and function of an insulin/IGF-associated
PI3 kinase in Strongyloides sterc oralis.
- Structure and function of a TGF-beta superfamily
growth factor in Strongyloides stercoralis.
Lab
personnel:
- • Holman Massey, Jr., Ph.D. –
Research Specialist
• Ariel Junio, M.S. – Research Specialist
• Michelle Castelletto – Graduate Student, MVP
-
last updated 8/2007
|
