Bradley L Reuhs

Purdue University, West Lafayette, Indiana, United States

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Publications (69)171.94 Total impact

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    ABSTRACT: Grape seed polyphenolic extract (GSPE) rich in the flavan-3-ols (+)-catechin and (-) epicatechin beneficially modulates Alzheimer's Disease phenotypes in animal models. The parent molecules in the extract are converted to a series of methylated and glucuronidated derivatives. To fully characterize these metabolites, and establish a robust quantitative assay of their levels in biological fluids, we have implemented a partial synthetic approach utilizing chemical methylation followed by enzymatic glucuronidation. Liquid chromatography/time-of-flight mass spectrometry (LC-TOF-MS) and nuclear magnetic resonance (NMR) spectroscopy were used to assign unequivocal structures to the compounds. An analytical method using solid-phase extraction and LC-MS/MS in multiple reaction monitoring mode (MRM) was validated for their quantitation in plasma. These studies provide a basis for improvements in future work on the bioavailability, metabolism and mechanism of action of metabolites derived from dietary flavan-3-ols in a range of interventions.
    No preview · Article · Feb 2015 · Journal of Agricultural and Food Chemistry
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    ABSTRACT: Dietary fibre of quinoa and amaranth was analysed for its insoluble and soluble fibre content, composition, and structure. Total dietary fibre content was 10% for quinoa and 11% for amaranth. For both pseudocereals, 78% of its dietary fibre was insoluble. Insoluble fibre (IDF) from quinoa and amaranth was mainly composed of galacturonic acid, arabinose, galactose, xylose and glucose. Linkage analysis indicated that IDF was composed of homogalacturonans and rhamnogalacturonan-I with arabinan side-chains (∼55-60%), as well as highly branched xyloglucans (∼30%) and cellulose. For both pseudocereals, 22% of total dietary fibre was soluble; a higher proportion than that found in wheat and maize (∼15%). The soluble fibre (SDF) was composed of glucose, galacturonic acid and arabinose; for amaranth, xylose was also a major constituent. Xyloglucans made up ∼40-60% of the SDF and arabinose-rich pectic polysaccharides represented ∼34-55%.
    Full-text · Article · Jan 2015 · Food Chemistry
  • Hui H. Chong · Senay Simsek · Bradley L. Reuhs

    No preview · Article · Jan 2014 · Food and Nutrition Sciences
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    ABSTRACT: The oat grain is often subjected to different hydrothermal treatments to inactivate hydrolytic enzymes that can have undesirable effects on the end-product quality. Hydrothermal treatments may affect the functional properties of oat starch. The objective of this work was to evaluate the effect of eight different hydrothermal treatments on the physicochemical and digestibility properties of oat starch. Hydrothermal treatments were selected based on heat treatment applications in oat industry and listed as HT-1) Ethanol boil HT-2) Ethanol boil and toasted HT-3) Steamed at 106 °C HT-4) Steamed at 106°C and toasted HT-5) Covered autoclaved at 120 °C HT-6) Uncovered autoclaved at 120 °C HT-7) Covered autoclaved at 130 °C and HT-8) Uncovered autoclaved at 130 °C. The morphology of the oat starch was altered as a result of various heat treatments. HT-5 and HT-7 treatments had more large starch granules than the other samples, however the apparent molecular weight of the starch from these samples was unaffected by the treatment. HT-6 and HT-8 resulted in the most sig-nificant changes to the gelatinization properties of the oat starch. HT-6 oat sample had significantly (P b 0.05) lower paste viscosity than starches from the oat samples with other treatments. The in vitro starch digestibility increased significantly (P b 0.05) for the HT-6 and HT-8 oat samples. This study demonstrated that thermal treatments can cause reorganization of the amylose and amylopectin chains that can result in changes in their physicochemical and digestibility properties. Published by Elsevier Ltd.
    Full-text · Article · Jun 2013 · Food Research International
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    ABSTRACT: For digestion of starch in humans, α-amylase first hydrolyzes starch molecules to produce α-limit dextrins, followed by complete hydrolysis to glucose by the mucosal α-glucosidases in the small intestine. It is known that α-1,6 linkages in starch are hydrolyzed at a lower rate than are α-1,4 linkages. Here, to create designed slowly digestible carbohydrates, the structure of waxy corn starch (WCS) was modified using a known branching enzyme alone (BE) and an in combination with β-amylase (BA) to increase further the α-1,6 branching ratio. The digestibility of the enzymatically synthesized products was investigated using α-amylase and four recombinant mammalian mucosal α-glucosidases. Enzyme-modified products (BE-WCS and BEBA-WCS) had increased percentage of α-1,6 linkages (WCS: 5.3%, BE-WCS: 7.1%, and BEBA-WCS: 12.9%), decreased weight-average molecular weight (WCS: 1.73×10(8) Da, BE-WCS: 2.76×10(5) Da, and BEBA-WCS 1.62×10(5) Da), and changes in linear chain distributions (WCS: 21.6, BE-WCS: 16.9, BEBA-WCS: 12.2 DPw). Hydrolysis by human pancreatic α-amylase resulted in an increase in the amount of branched α-limit dextrin from 26.8% (WCS) to 56.8% (BEBA-WCS). The α-amylolyzed samples were hydrolyzed by the individual α-glucosidases (100 U) and glucogenesis decreased with all as the branching ratio increased. This is the first report showing that hydrolysis rate of the mammalian mucosal α-glucosidases is limited by the amount of branched α-limit dextrin. When enzyme-treated materials were gavaged to rats, the level of postprandial blood glucose at 60 min from BEBA-WCS was significantly higher than for WCS or BE-WCS. Thus, highly branched glucan structures modified by BE and BA had a comparably slow digesting property both in vitro and in vivo. Such highly branched α-glucans show promise as a food ingredient to control postprandial glucose levels and to attain extended glucose release.
    Full-text · Article · Apr 2013 · PLoS ONE
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    Senay Simsek · Karl Wood · Bradley L Reuhs
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    ABSTRACT: Sinorhizobium meliloti NRG247 has a Fix+ phenotype on Medicago truncatula A20 and is Fix− on M. truncatula A17, and the phenotype is reversed with S. meliloti NRG185. As the succinoglycan was shown to impact host specificity, an analysis of the succinoglycan oligosaccharides produced by each strain was conducted. The symbiotically active succinoglycan trimeric oligosaccharides (STOs) from the two S. meliloti strains were compared by chromatography and mass spectrometry, and the analysis of the S. meliloti NRG247 oligosaccharides showed that this strain produces an abundance of STO trimer 1 (T1), containing no succinate (i.e., three nonsuccinylated repeats), yet the low-molecular-weight pool contained no nonsuccinylated monomers (potential repeats). This showed that STO T1 is likely to be the active signal on M. truncatula A20 and that the biosynthesis of the STOs is not a random polymerization of the monomer population. The results also suggest that the fully succinylated STO T7 is required for the infection of M. truncatula A17.
    Full-text · Article · Mar 2013 · Journal of bacteriology
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    ABSTRACT: Pseudomonas aeruginosa is an important opportunistic bacterial pathogen. Despite its metabolic and virulence versatility, it has not been shown to infect articular joints, which are environments that are rarely infected with bacteria in general. We hypothesized that articular joints possess antimicrobial activity that limits bacterial survival in these environments. We report that cartilages secrete a novel antimicrobial factor, henceforth referred to as the Cartilage Associated Antimicrobial Factor (CA-AMF), with potent antimicrobial activity. Importantly, CA-AMF exhibited significantly more antimicrobial activity against P. aeruginosa strains with a functional type III secretion system (T3SS). We propose that CA-AMF represents a new class of human antimicrobial factors in innate immunity, one which has evolved to selectively target pathogenic bacteria among the beneficial and commensal microflora. The T3SS is the first example of a pathogen-specific molecular target in this antimicrobial defense system.
    Full-text · Article · Jan 2013 · Journal of Medical Microbiology
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    ABSTRACT: A variety of products of plant origin, such as tomatoes, melons, peppers, and peanuts, have been implicated in Salmonella spp. associated outbreaks in recent years. Although these bacteria have been found to internalize within some plants associated with foodborne-related outbreaks, the internalization in peanut plants has not been examined to date. To investigate internalization and where the bacteria localize within the plant, intact peanut seeds were contaminated with Salmonella serovar Typhimurium expressing green fluorescent protein (GFP) for 30 min and immunocytochemical techniques were used to localize the bacterium within the stem tissue of 16 day-old peanut plants. An average of 13.6 bacteria/mm3 were localized within the sampled tissue. The bacteria were found to be associated with every major tissue (cortical, vascular, epidermal, and pith) and corresponding cell type. The cortical cells located to the outside of the vascular bundles contained the majority of the Salmonella cells (72.4%). Additional growth experiments demonstrated peanut seedlings could support the reproduction of Salmonella to high levels (109 CFU/plant) after 2 days following seed contamination. Together these results show that Salmonella Typhimurium can internalize within many different plant tissue types after a brief seed contamination event and that the bacteria are able to grow and persist within the plant.
    No preview · Article · Mar 2012 · Food Research International
  • R Davis · A Deering · Y Burgula · L.J. Mauer · B.L. Reuhs
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    ABSTRACT: To apply specific collection techniques and spectroscopy to differentiate between live and dead Escherichia coli O157:H7 cells, as well as cells subjected to various inactivation treatments, including heat, salt, UV, antibiotics and alcohol. Fourier transform-infrared (FT-IR) spectroscopy was used to analyse E. coli O157:H7 cells, after filtration or immunomagnetic collection. Partial least squares analysis of the spectra quantified live E. coli O157:H7 in the presence of dead cells with an R(2) > 0·996. Canonical variate analysis (CVA) not only differentiated between spectra of 100% dead and 100% live cells but also between 1% live : 99% dead and 100% dead. CVA using principal components also differentiated between the spectra of the differentially treated cells at a 95% confidence level, and Cooman plots showed clear separation between clusters of spectra of bacteria exposed to the different inactivation treatments. Mahalanobis distances (MD) corroborated the results of CVA. These results demonstrated the effectiveness of rapid cell collection and FT-IR spectroscopy techniques to differentiate between live and dead E. coli O157:H7 cells. This technique has potential applications for use with foods subjected to various inactivation treatments.
    No preview · Article · Dec 2011 · Journal of Applied Microbiology
  • Amanda J Deering · Robert E Pruitt · Lisa J Mauer · Bradley L Reuhs
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    ABSTRACT: Escherichia coli O157:H7 has been associated with numerous outbreaks involving fresh produce. Previous studies have shown that bacteria can be internalized within plant tissue and that this can be a source of protection from antimicrobial chemicals and environmental conditions. However, the types of tissue and cellular locations the bacteria occupy in the plant following internalization have not been addressed. In this study, immunocytochemical techniques were used to localize internalized E. coli O157:H7 expressing green fluorescent protein in germinated mung bean (Vigna radiata) hypocotyl tissue following contamination of intact seeds. An average of 13 bacteria per mm(3) were localized within the sampled tissue. The bacteria were found to be associated with every major tissue and corresponding cell type (cortex, phloem, xylem, epidermis, and pith). The cortical cells located on the outside of the vascular bundles contained the majority of the internalized bacteria (61%). In addition, the bacteria were localized primarily to the spaces between the cells (apoplast) and not within the cells. Growth experiments were also performed and demonstrated that mung bean plants could support the replication of bacteria to high levels (10(7) CFU per plant) following seed contamination and that these levels could be sustained over a 12-day period. Therefore, E. coli O157:H7 can be internalized in many different plant tissue types after a brief seed contamination event, and the bacteria are able to grow and persist within the plant.
    No preview · Article · Aug 2011 · Journal of food protection
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    R Davis · Y Burgula · A Deering · J Irudayaraj · B.L. Reuhs · L.J. Mauer
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    ABSTRACT: To evaluate Fourier transform infrared (FT-IR) techniques for detecting, quantifying, and differentiating viable and heat-treated cells of Salmonella enterica serovars from chicken breast.   Salmonella enterica serovars were captured from inoculated chicken breast by filtration and immunomagnetic separation (IMS) prior to spectral collection using an FT-IR spectrometer and IR microscopy. The detection limits, based on amide II peak area (1589 to 1493 cm(-1) ), for the Filtration-FT-IR and IMS-FT-IR methods were 10(6) and 10(4) CFU g(-1) , respectively. The bacteria were detectable after 6 h of culture enrichment during a sensitivity experiment with lower initial inoculum of 10(1) CFU g(-1) . Canonical variate analysis differentiated experimental from control spectra at a level of 10(3) CFU g(-1) . Partial least squares models were established for the quantification of Salm. enterica from chicken breast using Filtration-FT-IR (R(2) ≥ 0·95, RMSEC ≤ 0·62) and IMS-FT-IR (R(2) ≥ 0·80, RMSEC ≤ 1·61) methods. Filtration-FT-IR was also used to detect and quantify live Salm. enterica in the presence of heat-treated cells with R(2) = 0·996, and this approach was comparable to the results of a commercial stain (BacLight™; R(2) = 0·998). Discriminant and canonical variate analyses of the spectra differentiated live and dead cells of different serovars of Salm. enterica. FT-IR analysis coupled with separation methods is useful for the rapid detection and differentiation of Salm. enterica separated from chicken. FT-IR-based methods are faster than traditional microbiological methods and can be used for the detection of live and dead bacteria from complex foods.
    Full-text · Article · Dec 2010 · Journal of Applied Microbiology
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    ABSTRACT: To better protect consumers from exposure to produce contaminated with Escherichia coli, the potential transfer of E. coli from manure or irrigation water to plants must be better understood. We used E. coli strains expressing bioluminescence (E. coli O157:H7 lux) or multiantibiotic resistance (E. coli²(+)) in this study. These marked strains enabled us to visualize in situ rhizosphere colonization and metabolic activity and to track the occurrence and survival of E. coli in soil, rhizosphere, and phyllosphere. When radish and lettuce seeds were treated with E. coli O157:H7 lux and grown in an agar-based growth system, rapid bacterial colonization of the germinating seedlings and high levels of microbial activity were seen. Introduction of E. coli²(+) to soil via manure or via manure in irrigation water showed that E. coli could establish itself in the lettuce rhizosphere. Regardless of introduction method, 15 days subsequent to its establishment in the rhizosphere, E. coli²(+) was detected on the phyllosphere of lettuce at an average number of 2.5 log CFU/g. When E. coli²(+) was introduced 17 and 32 days postseeding to untreated soil (rather than the plant surface) via irrigation, it was detected at low levels (1.4 log CFU/g) on the lettuce phyllosphere 10 days later. While E. coli²(+) persisted in the bulk and rhizosphere soil throughout the study period (day 41), it was not detected on the external portions of the phyllosphere after 27 days. Overall, we find that E. coli is mobile in the plant system and responds to the rhizosphere like other bacteria.
    No preview · Article · Nov 2010 · Journal of food protection
  • Reeta Davis · Joseph Irudayaraj · Bradley L Reuhs · Lisa J Mauer
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    ABSTRACT: FT-IR spectroscopy methods for detection, differentiation, and quantification of E. coli O157:H7 strains separated from ground beef were developed. Filtration and immunomagnetic separation (IMS) were used to extract live and dead E. coli O157:H7 cells from contaminated ground beef prior to spectral acquisition. Spectra were analyzed using chemometric techniques in OPUS, TQ Analyst, and WinDAS software programs. Standard plate counts were used for development and validation of spectral analyses. The detection limit based on a selectivity value using the OPUS ident test was 10(5) CFU/g for both Filtration-FT-IR and IMS-FT-IR methods. Experiments using ground beef inoculated with fewer cells (10(1) to 10(2) CFU/g) reached the detection limit at 6 h incubation. Partial least squares (PLS) models with cross validation were used to establish relationships between plate counts and FT-IR spectra. Better PLS predictions were obtained for quantifying live E. coli O157:H7 strains (R(2)> or = 0.9955, RMSEE < or = 0.17, RPD > or = 14) and different ratios of live and dead E. coli O157:H7 cells (R(2)= 0.9945, RMSEE = 2.75, RPD = 13.43) from ground beef using Filtration-FT-IR than IMS-FT-IR methods. Discriminant analysis and canonical variate analysis (CVA) of the spectra differentiated various strains of E. coli O157:H7 from an apathogenic control strain. CVA also separated spectra of 100% dead cells separated from ground beef from spectra of 0.5% live cells in the presence of 99.5% dead cells of E. coli O157:H7. These combined separation and FT-IR methods could be useful for rapid detection and differentiation of pathogens in complex foods.
    No preview · Article · Aug 2010 · Journal of Food Science
  • A. J. Deering · B. L. Reuhs · L. J. Mauer
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    ABSTRACT: Fourier-transform infrared spectroscopy (FT-IR) utilizes nanostructural differences between bacterial cells for the rapid identification, classification, and differentiation of many species of bacteria, but most studies have used only live cells. A rapid and reliable method for determining the total number of live and dead bacterial cells in a food could prevent the distribution of unsafe products to consumers. In this study, infrared spectra (4000-700 cm-1) were collected using a Continuμm IR microscope attached to a ThermoNicolet Nexus 670 FT-IR spectrophotometer from varying concentrations of live and dead E. coli (ATTC® 25922™) cells. Spectra were analyzed using chemometric methods. Canonical variate analysis (CVA) and Mahalanobis distances (MD) quantified the spectral differences between 100% live and 100% dead bacteria, with linear discriminant analysis (LDA) using principal components able to successfully classify and differentiate between the two treatments (50 out of 50 correctly assigned). CVA and MD were also 100% successful in quantifying the spectral differences between 100% dead bacteria and samples containing as little as 0.1% live cells. The PLS method accurately quantified live cells in the presence of dead cells (R = 0.981), and Cooman plots showed clear separation between clusters of live and dead bacteria. To compare detection limits with qPCR, dead bacterial cells were treated with ethidium bromide monoazide (EMA) to prevent amplification of DNA from these cells and enable the detection of both live and dead cells using universal bacterial primer sets. The qPCR techniques using EMA-treated bacteria could also detect live cell concentrations as low as 0.1%. However, the total analysis time for detection using qPCR is ~6 hours in comparison to ~30 minutes using FT-IR. Therefore, FT-IR is a useful tool for the rapid differentiation between live and dead bacterial samples, even when the concen- - tration of live bacteria is as low as 0.1% of the target microbe.
    No preview · Article · Jun 2010 · University/Government/Industry Microelectronics Symposium, 1989. Proceedings., Eighth
  • R. Davis · Y. Burgula · J. Irudayaraj · B. L. Reuhs · L. J. Mauer
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    ABSTRACT: The majority of Escherichia coli O157:H7 outbreaks are associated with ground beef. To detect this pathogen, separation techniques were tested with E. coli O157:H7 in ground beef followed by FT-IR analyses. Ground beef samples were inoculated with various levels of live and heat treated E. coli O157:H7 cells and the bacteria were extracted by filtration or immunomagnetic separation (IMS). Spectra were collected and detection limits were established by discriminant analysis of the 1800-800 cm-1 region and comparison to standard plate counts. The detection limit for the Filtration-FT-IR and IMS-FT-IR assays was 105 CFU/g. Partial least squares model established significant linear relationships between plate counts and spectra [R ≥ 0.99]. Discriminant analysis and canonical variate analysis of the spectra differentiated live and heat treated cells of E. coli O157:H7. Validation experiments using ground beef inoculated with fewer cells (101- 102 CFU/g) reached the detection limit within a six hour incubation. A portable IR sensor was also used to detect E. coli O157:H7 in ground beef, and the detection limit was 107 CFU/g. The total time to detection for Filtration-FT-IR and IMS-FT-IR were one hour and 3.75 h, respectively which is faster than conventional plate count methods (48h) and conventional IMS methods (48h). The FT-IR methods developed are potentially rapid and simple protocols that could be further developed for the detection of different species of pathogenic bacteria in complex food systems.
    No preview · Article · Jan 2010 · University/Government/Industry Microelectronics Symposium, 1989. Proceedings., Eighth
  • Bradley L. Reuhs · Senay Simsek
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    ABSTRACT: Nuclear magnetic resonance (NMR) spectroscopy is a powerful analytical technique with a wide variety of applications. It may be used for complex structural studies, for protocol or process development, or as a simple quality assay for which structural information is important. It is nondestructive, and high-quality data may be obtained from milligram, even microgram, quantities of sample. Whereas other spectroscopy techniques may be used to determine the nature of the functional groups present in a sample, only NMR spectroscopy can provide the data necessary to determine the complete structure of a molecule. The applicability of NMR to food analysis has increased over the last three decades. In addition to improved instrumentation and much lower costs, very complex and specialized NMR techniques can now be routinely performed by a student or technician. These experiments can be set up with the click of a button/icon, as all the basic parameters are embedded into default experiment files listed in the data/work station software, and the results are obtained in a short time.
    No preview · Chapter · Dec 2009
  • Baraem Ismail · Bradley L. Reuhs · S. Suzanne Nielsen
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    ABSTRACT: The food chain that starts with farmers and ends with consumers can be complex, involving multiple stages of production and distribution (planting, harvesting, breeding, transporting, storing, importing, processing, packaging, distributing to retail markets, and shelf storing) (Fig. 18.1). Various practices can be employed at each stage in the food chain, which may include pesticide treatment, agricultural bioengineering, veterinary drug administration, environmental and storage conditions, processing applications, economic gain practices, use of food additives, choice of packaging material, etc. Each of these practices can play a major role in food quality and safety, due to the possibility of contamination with or introduction (intentionally and nonintentionally) of hazardous substances or constituents. Legislation and regulation to ensure food quality and safety are in place and continue to develop to protect the stakeholders, namely farmers, consumers, and industry. [Refer to reference (1) for information on regulations of food contaminants and residues.]
    No preview · Chapter · Dec 2009
  • Bradley L. Reuhs · Mary Ann Rounds
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    ABSTRACT: High-performance liquid chromatography (HPLC) developed during the 1960s as a direct offshoot of classic column liquid chromatography through improvements in the technology of columns and instrumental components (pumps, injection valves, and detectors). Originally, HPLC was the acronym for high-pressure liquid chromatography, reflecting the high operating pressures generated by early columns. By the late 1970s, however, high-performance liquid chromatography had become the preferred term, emphasizing the effective separations achieved. In fact, newer columns and packing materials offer high performance at moderate pressure (although still high pressure relative to gravity-flow liquid chromatography). HPLC can be applied to the analysis of any compound with solubility in a liquid that can be used as the mobile phase. Although most frequently employed as an analytical technique, HPLC also may be used in the preparative mode.
    No preview · Chapter · Dec 2009
  • Hui H. Chong · Senay Simsek · Bradley L. Reuhs
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    ABSTRACT: The initial processing of tomatoes includes a break step, which involves rapid heating of the freshly chopped tomatoes to >90 °C for hot break, or 60–77 °C for cold break. It is believed that pectolytic enzyme deactivation is the key element in the hot break step; therefore the pectin content of the different products should be qualitatively distinct. There are two general sources of pectin in a tomato fruit: the middle lamella which is rich in homogalacturonan, and the cell-wall. In this study, a 0-min or 24-min hold time (room temperature) for the chopped tomatoes preceded the break step to replicate hot and cold break, respectively, with minimum variation in the processing. The cell-wall pectin was then isolated and analyzed for the carbohydrate composition, degree of polymerization, and degree of esterification. The results showed no observable differences in pectin isolated from the two preparations, indicating that there is no significant pectolytic activity in the cell wall during the 24 min hold time; thus, the pectolytic enzymes probably act on the lower ester, middle lamella pectin in cold break products.
    No preview · Article · Aug 2009 · Food Research International
  • Senay Simsek · Tuula Ojanen-Reuhs · Corinne Marie · Bradley L Reuhs
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    ABSTRACT: Cultured cells of Sinorhizobium sp. NGR234 produce an abundance of capsular polysaccharides, or K antigens; however, cells that are cultured in the presence of apigenin, a nod gene inducer, exhibited a significant reduction in K-antigen production. The flavonoid-induced modulation in capsule production appeared to be related to the phase-shift changes associated with bacteroid differentiation. Therefore, the polysaccharides were extracted from Sinorhizobium sp. NGR234 bacteroids recovered from Vigna unguiculata cv Red Caloona root nodules, and subsequent analyses showed that the bacteroid extracts were virtually devoid of K-antigen. Polysaccharide extracts from two nodulation mutants cultured in the presence of apigenin were then analyzed, and the results showed that the flavonoid-inducible decrease in K-antigen production is y4gM- and nodD1-dependent.
    No preview · Article · Aug 2009 · Carbohydrate research

Publication Stats

2k Citations
171.94 Total Impact Points


  • 2002-2015
    • Purdue University
      • • Whistler Center for Carbohydrate Research
      • • Department of Food Science
      West Lafayette, Indiana, United States
  • 2007
    • Duke University Medical Center
      • Department of Cell Biology
      Durham, North Carolina, United States
  • 1990-2004
    • University of Georgia
      • Complex Carbohydrate Research Center
      Атина, Georgia, United States
  • 1999
    • University of Missouri
      Columbia, Missouri, United States
  • 1998
    • Massachusetts Institute of Technology
      • Department of Biology
      Cambridge, Massachusetts, United States
  • 1997
    • University of North Carolina at Chapel Hill
      • Department of Biology
      North Carolina, United States