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Biomedical subjects

Philip A Lessard

Publications and source records attributed to Philip A Lessard.

3 recordsLinked to original sources

Genetic diversity of Eurycoma longifolia inferred from single nucleotide polymorphisms.

Eurycoma longifolia Jack. is a treelet that grows in the forests of Southeast Asia and is widely used throughout the region because of its reported medicinal properties. Widespread harvesting of wild-grown trees has led to rapid thinning of natural populations, causing a potential decrease in genetic diversity among E. longifolia. Suitable genetic markers would be very useful for propagation and breeding programs to support conservation of this species, although no such markers currently exist. To meet this need, we have applied a genome complexity reduction strategy to identify a series of single nucleotide polymorphisms (SNPs) within the genomes of several E. longifolia accessions. We have found that the occurrence of these SNPs reflects the geographic origins of individual plants and can distinguish different natural populations. This work demonstrates the rapid development of molecular genetic markers in species for which little or no genomic sequence information is available. The SNP markers that we have developed in this study will also be useful for identifying genetic fingerprints that correlate with other properties of E. longifolia, such as high regenerability or the appearance of bioactive metabolites.

Conservation of Natural Resources↗

Optimizing bioconversion pathways through systems analysis and metabolic engineering.

We demonstrate a general approach for metabolic engineering of biocatalytic systems comprising the uses of a chemostat for strain improvement and radioisotopic tracers for the quantification of pathway fluxes. Flux determination allows the identification of target pathways for modification as validated by subsequent overexpression of the corresponding gene. We demonstrate this method in the indene bioconversion network of Rhodococcus modified for the overproduction of 1,2-indandiol, a key precursor for the AIDS drug Crixivan.

Biomedical Engineering↗

Manipulating gene expression for the metabolic engineering of plants.

Introducing and expressing foreign genes in plants present many technical challenges that are not encountered with microbial systems. This review addresses the variety of issues that must be considered and the variety of options that are available, in terms of choosing transformation systems and designing recombinant transgenes to ensure appropriate expression in plant cells. Tissue specificity and proper developmental regulation, as well as proper subcellular localization of products, must be dealt with for successful metabolic engineering in plants..

Biomarkers↗