Jason Walther

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Contact Information

Jason Walther
Laboratory for Bioinformatics and Metabolic Engineering
Department of Chemical Engineering
Building 56, Room 422
77 Massachusetts Avenue
Cambridge, MA 02139
Phone: (617) 253-6591
Fax: (617) 253-7181

Research Interests

The goal of metabolic flux analysis (MFA) is the quantitative determination of all intracellular fluxes in a system of interest. Results are obtained by introducing a labeled substrate (usually a labeled carbon source) into a cell culture, measuring relative labeling in metabolic byproducts, and computationally processing these measurements to arrive at fluxes.
Nonstationary metabolic flux analysis (NMFA) is similar to MFA with the provision that metabolite labeling is sampled and measured before the system reaches an isotopic steady state. NMFA, though computationally more complex, claims several advantages over its stationary analog. First, the amount of prohibitively expensive labeled substrate required for an experiment is greatly reduced. Second, the duration of such an experiment is considerably shortened, adding credibility to the metabolic steady-state assumption necessary for all flux analyses. Third, nonstationary flux analysis allows the pool sizes of metabolites, including intracellular intermediates, to be estimated in addition to the fluxes themselves.
I am working with the theoretical, computational, and experimental aspects of NMFA. In particular, I hope to apply NMFA to different strains of Saccharomyces cerevisiae to shed light on the metabolic impact of certain genetic modifications.


2004 M.Eng. Chemical Engineering, Stanford University
2004 B.S. Chemical Engineering, Stanford University


Young JD,* Walther JL,* Antoniewicz MR, Yoo H, and Stephanopoulos G. An elementary metabolite unit (EMU) based method of nonstationary flux analysis. 2007. Biotechnol Bioeng doi:10.1002/bit.21632.
Styczynski MP, Moxley JF, Tong LV, Walther JL, Jensen KL, and Stephanopoulos, G. Systematic identification of conserved metabolites in GC/MS data for metabolomics and biomarker discovery. 2007. Anal Chem 79(3):966-973.
Meyer TW, Peattie JW, Miller JD, Dinh DC, Recht NS, Walther JL, and Hostetter TH. Increasing the clearance of protein-bound solutes by addition of a sorbent to the dialysate. 2007. J Am Soc Nephrol 18(3):868-874.
Walther JL, Bartlett DW, Chew W, Robertson CR, Hostetter TH, and Meyer TW. 2006. Downloadable computer models for renal replacement therapy. Kidney Int 69(6):1056-1063.
Meyer TW, Walther JL, Pagtalunan ME, Martinez AW, Torkamani A, Fong PD, Recht NS, Robertson CR, and Hostetter TH. The clearance of protein-bound solutes by hemofiltration and hemodiafiltration. 2005. Kidney Int 68(2):867-877.
*These authors contributed equally to the work