Hoda Khouri

J. Craig Venter Institute, Роквилл, Maryland, United States

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Publications (61)823.33 Total impact

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    ABSTRACT: Haloferax volcanii is an easily culturable moderate halophile that grows on simple defined media, is readily transformable, and has a relatively stable genome. This, in combination with its biochemical and genetic tractability, has made Hfx. volcanii a key model organism, not only for the study of halophilicity, but also for archaeal biology in general. We report here the sequencing and analysis of the genome of Hfx. volcanii DS2, the type strain of this species. The genome contains a main 2.848 Mb chromosome, three smaller chromosomes pHV1, 3, 4 (85, 438, 636 kb, respectively) and the pHV2 plasmid (6.4 kb). The completed genome sequence, presented here, provides an invaluable tool for further in vivo and in vitro studies of Hfx. volcanii.
    PLoS ONE 04/2015; 5(3):e9605. DOI:10.1371/journal.pone.0009605 · 3.53 Impact Factor
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    ABSTRACT: Here, we present the complete 2,003,803-bp genome of a sulfate-reducing thermophilic bacterium, Thermodesulfovibrio yellowstonii strain DSM 11347T. FOOTNOTES Address correspondence to Jonathan A. Eisen, jaeisen{at}ucdavis.edu. ↵* Present address: Hoda M. Khouri, Independent Consultant, Bethesda, Maryland, USA. Citation Bhatnagar S, Badger JH, Madupu R, Khouri HM, O’Connor EM, Robb FT, Ward NL, Eisen JA. 2015. Genome sequence of the sulfate-reducing thermophilic bacterium Thermodesulfovibrio yellowstonii strain DSM 11347T (phylum Nitrospirae). Genome Announc 3(1):e01489-14. doi:10.1128/genomeA.01489-14. Received 10 December 2014. Accepted 15 December 2014. Published 29 January 2015. Copyright © 2015 Bhatnagar et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 3.0 Unported license.
    Genome Announcements 01/2015; 3(1). DOI:10.1128/genomeA.01489-14
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    ABSTRACT: Here, we present the complete genome sequence of Thermodesulfobacterium commune DSM 2178T of the phylum Thermodesulfobacteria. FOOTNOTES Address correspondence to Jonathan A. Eisen, jaeisen{at}ucdavis.edu. ↵* Present address: Hoda M. Khouri, Independent Consultant, Bethesda, Maryland, USA. Citation Bhatnagar S, Badger JH, Madupu R, Khouri HM, O’Connor EM, Robb FT, Ward NL, Eisen JA. 2014. Genome sequence of a sulfate-reducing thermophilic bacterium, Thermodesulfobacterium commune DSM 2178T (phylum Thermodesulfobacteria). Genome Announc 3(1):e01490-14. doi:10.1128/genomeA.01490-14. Received 10 December 2014. Accepted 15 December 2014. Published 29 January 2015. Copyright © 2015 Bhatnagar et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 3.0 Unported license.
    Genome Announcements 01/2015; 3(1). DOI:10.1128/genomeA.01490-14
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    ABSTRACT: Here we present the draft genome of Synergistes jonesii 78-1, ATCC 49833, a member of the Synergistes phylum. This organism was isolated from the rumen of a Hawaiian goat and ferments pyridinediols. The assembly contains 2,747,397 bp in 61 contigs.
    Genome Announcements 07/2014; 2(4). DOI:10.1128/genomeA.00833-14
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    Dataset: Chain.SOM
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    ABSTRACT: Lyme disease is the most common tick-borne human illness in North America. In order to understand the molecular pathogenesis, natural diversity, population structure and epizootic spread of the North American Lyme agent, Borrelia burgdorferi sensu stricto, a much better understanding of the natural diversity of its genome will be required. Towards this end we present a comparative analysis of the nucleotide sequences of the numerous plasmids of B. burgdorferi isolates B31, N40, JD1 and 297. These strains were chosen because they include the three most commonly studied laboratory strains, and because they represent different major genetic lineages and so are informative regarding the genetic diversity and evolution of this organism. A unique feature of Borrelia genomes is that they carry a large number of linear and circular plasmids, and this work shows that strains N40, JD1, 297 and B31 carry related but non-identical sets of 16, 20, 19 and 21 plasmids, respectively, that comprise 33-40% of their genomes. We deduce that there are at least 28 plasmid compatibility types among the four strains. The B. burgdorferi ∼900 Kbp linear chromosomes are evolutionarily exceptionally stable, except for a short ≤20 Kbp plasmid-like section at the right end. A few of the plasmids, including the linear lp54 and circular cp26, are also very stable. We show here that the other plasmids, especially the linear ones, are considerably more variable. Nearly all of the linear plasmids have undergone one or more substantial inter-plasmid rearrangements since their last common ancestor. In spite of these rearrangements and differences in plasmid contents, the overall gene complement of the different isolates has remained relatively constant.
    PLoS ONE 03/2012; 7(3):e33280. DOI:10.1371/journal.pone.0033280 · 3.53 Impact Factor
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    ABSTRACT: Castor bean is an important oil-producing plant in the Euphorbiaceae family. Its high-quality oil contains up to 90% of the unusual fatty acid ricinoleate, which has many industrial and medical applications. Castor bean seeds also contain ricin, a highly toxic Type 2 ribosome-inactivating protein, which has gained relevance in recent years due to biosafety concerns. In order to gain knowledge on global genetic diversity in castor bean and to ultimately help the development of breeding and forensic tools, we carried out an extensive chloroplast sequence diversity analysis. Taking advantage of the recently published genome sequence of castor bean, we assembled the chloroplast and mitochondrion genomes extracting selected reads from the available whole genome shotgun reads. Using the chloroplast reference genome we used the methylation filtration technique to readily obtain draft genome sequences of 7 geographically and genetically diverse castor bean accessions. These sequence data were used to identify single nucleotide polymorphism markers and phylogenetic analysis resulted in the identification of two major clades that were not apparent in previous population genetic studies using genetic markers derived from nuclear DNA. Two distinct sub-clades could be defined within each major clade and large-scale genotyping of castor bean populations worldwide confirmed previously observed low levels of genetic diversity and showed a broad geographic distribution of each sub-clade.
    PLoS ONE 07/2011; 6(7):e21743. DOI:10.1371/journal.pone.0021743 · 3.53 Impact Factor
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    Nature 10/2010; 467:1061-1073. · 42.35 Impact Factor
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    Nature 10/2010; 467(7319):1061-1073. DOI:10.1038/nature09534 · 42.35 Impact Factor
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    ABSTRACT: For over a decade, genome 43 sequences have adhered to only two standards that are relied on for purposes of sequence analysis by interested third parties (1, 2). However, ongoing developments in revolutionary sequencing technologies have resulted in a redefinition of traditional whole genome sequencing that requires a careful reevaluation of such standards. With commercially available 454 pyrosequencing (followed by Illumina, SOLiD, and now Helicos), there has been an explosion of genomes sequenced under the moniker 'draft', however these can be very poor quality genomes (due to inherent errors in the sequencing technologies, and the inability of assembly programs to fully address these errors). Further, one can only infer that such draft genomes may be of poor quality by navigating through the databases to find the number and type of reads deposited in sequence trace repositories (and not all genomes have this available), or to identify the number of contigs or genome fragments deposited to the database. The difficulty in assessing the quality of such deposited genomes has created some havoc for genome analysis pipelines and contributed to many wasted hours of (mis)interpretation. These same novel sequencing technologies have also brought an exponential leap in raw sequencing capability, and at greatly reduced prices that have further skewed the time- and cost-ratios of draft data generation versus the painstaking process of improving and finishing a genome. The resulting effect is an ever-widening gap between drafted and finished genomes that only promises to continue (Figure 1), hence there is an urgent need to distinguish good and poor datasets. The sequencing institutes in the authorship, along with the NIH's Human Microbiome Project Jumpstart Consortium (3), strongly believe that a new set of standards is required for genome sequences. The following represents a set of six community-defined categories of genome sequence standards that better reflect the quality of the genome sequence, based on our collective understanding of the different technologies, available assemblers, and the varied efforts to improve upon drafted genomes. Due to the increasingly rapid pace of genomics we avoided the use of rigid numerical thresholds in our definitions to take into account the types of products achieved by any combination of technology, chemistry, assembler, or improvement/finishing process.
    Science 10/2009; 326(5950):236-7. DOI:10.1126/science.1180614 · 31.48 Impact Factor
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    ABSTRACT: The complete genomes of three strains from the phylum Acidobacteria were compared. Phylogenetic analysis placed them as a unique phylum. They share genomic traits with members of the Proteobacteria, the Cyanobacteria, and the Fungi. The three strains appear to be versatile heterotrophs. Genomic and culture traits indicate the use of carbon sources that span simple sugars to more complex substrates such as hemicellulose, cellulose, and chitin. The genomes encode low-specificity major facilitator superfamily transporters and high-affinity ABC transporters for sugars, suggesting that they are best suited to low-nutrient conditions. They appear capable of nitrate and nitrite reduction but not N(2) fixation or denitrification. The genomes contained numerous genes that encode siderophore receptors, but no evidence of siderophore production was found, suggesting that they may obtain iron via interaction with other microorganisms. The presence of cellulose synthesis genes and a large class of novel high-molecular-weight excreted proteins suggests potential traits for desiccation resistance, biofilm formation, and/or contribution to soil structure. Polyketide synthase and macrolide glycosylation genes suggest the production of novel antimicrobial compounds. Genes that encode a variety of novel proteins were also identified. The abundance of acidobacteria in soils worldwide and the breadth of potential carbon use by the sequenced strains suggest significant and previously unrecognized contributions to the terrestrial carbon cycle. Combining our genomic evidence with available culture traits, we postulate that cells of these isolates are long-lived, divide slowly, exhibit slow metabolic rates under low-nutrient conditions, and are well equipped to tolerate fluctuations in soil hydration.
    Applied and Environmental Microbiology 03/2009; 75(7):2046-56. DOI:10.1128/AEM.02294-08 · 3.95 Impact Factor
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    ABSTRACT: Submarine hydrothermal vents are model systems for the Archaean Earth environment, and some sites maintain conditions that may have favored the formation and evolution of cellular life. Vents are typified by rapid fluctuations in temperature and redox potential that impose a strong selective pressure on resident microbial communities. Nautilia profundicola strain Am-H is a moderately thermophilic, deeply-branching Epsilonproteobacterium found free-living at hydrothermal vents and is a member of the microbial mass on the dorsal surface of vent polychaete, Alvinella pompejana. Analysis of the 1.7-Mbp genome of N. profundicola uncovered adaptations to the vent environment—some unique and some shared with other Epsilonproteobacterial genomes. The major findings included: (1) a diverse suite of hydrogenases coupled to a relatively simple electron transport chain, (2) numerous stress response systems, (3) a novel predicted nitrate assimilation pathway with hydroxylamine as a key intermediate, and (4) a gene (rgy) encoding the hallmark protein for hyperthermophilic growth, reverse gyrase. Additional experiments indicated that expression of rgy in strain Am-H was induced over 100-fold with a 20°C increase above the optimal growth temperature of this bacterium and that closely related rgy genes are present and expressed in bacterial communities residing in geographically distinct thermophilic environments. N. profundicola, therefore, is a model Epsilonproteobacterium that contains all the genes necessary for life in the extreme conditions widely believed to reflect those in the Archaean biosphere—anaerobic, sulfur, H2- and CO2-rich, with fluctuating redox potentials and temperatures. In addition, reverse gyrase appears to be an important and common adaptation for mesophiles and moderate thermophiles that inhabit ecological niches characterized by rapid and frequent temperature fluctuations and, as such, can no longer be considered a unique feature of hyperthermophiles.
    PLoS Genetics 03/2009; 5(2):e1000362. DOI:10.1371/journal.pgen.1000362 · 8.17 Impact Factor
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    ABSTRACT: Brucella ovis is a veterinary pathogen associated with epididymitis in sheep. Despite its genetic similarity to the zoonotic pathogens B. abortus, B. melitensis and B. suis, B. ovis does not cause zoonotic disease. Genomic analysis of the type strain ATCC25840 revealed a high percentage of pseudogenes and increased numbers of transposable elements compared to the zoonotic Brucella species, suggesting that genome degradation has occurred concomitant with narrowing of the host range of B. ovis. The absence of genomic island 2, encoding functions required for lipopolysaccharide biosynthesis, as well as inactivation of genes encoding urease, nutrient uptake and utilization, and outer membrane proteins may be factors contributing to the avirulence of B. ovis for humans. A 26.5 kb region of B. ovis ATCC25840 Chromosome II was absent from all the sequenced human pathogenic Brucella genomes, but was present in all of 17 B. ovis isolates tested and in three B. ceti isolates, suggesting that this DNA region may be of use for differentiating B. ovis from other Brucella spp. This is the first genomic analysis of a non-zoonotic Brucella species. The results suggest that inactivation of genes involved in nutrient acquisition and utilization, cell envelope structure and urease may have played a role in narrowing of the tissue tropism and host range of B. ovis.
    PLoS ONE 02/2009; 4(5):e5519. DOI:10.1371/journal.pone.0005519 · 3.53 Impact Factor
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    ABSTRACT: The plant cell wall, which consists of a highly complex array of interconnecting polysaccharides, is the most abundant source of organic carbon in the biosphere. Microorganisms that degrade the plant cell wall synthesize an extensive portfolio of hydrolytic enzymes that display highly complex molecular architectures. To unravel the intricate repertoire of plant cell wall-degrading enzymes synthesized by the saprophytic soil bacterium Cellvibrio japonicus, we sequenced and analyzed its genome, which predicts that the bacterium contains the complete repertoire of enzymes required to degrade plant cell wall and storage polysaccharides. Approximately one-third of these putative proteins (57) are predicted to contain carbohydrate binding modules derived from 13 of the 49 known families. Sequence analysis reveals approximately 130 predicted glycoside hydrolases that target the major structural and storage plant polysaccharides. In common with that of the colonic prokaryote Bacteroides thetaiotaomicron, the genome of C. japonicus is predicted to encode a large number of GH43 enzymes, suggesting that the extensive arabinose decorations appended to pectins and xylans may represent a major nutrient source, not just for intestinal bacteria but also for microorganisms that occupy terrestrial ecosystems. The results presented here predict that C. japonicus possesses an extensive range of glycoside hydrolases, lyases, and esterases. Most importantly, the genome of C. japonicus is remarkably similar to that of the gram-negative marine bacterium, Saccharophagus degradans 2-40(T). Approximately 50% of the predicted C. japonicus plant-degradative apparatus appears to be shared with S. degradans, consistent with the utilization of plant-derived complex carbohydrates as a major substrate by both organisms.
    Journal of bacteriology 09/2008; 190(15):5455-63. DOI:10.1128/JB.01701-07 · 2.69 Impact Factor
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    ABSTRACT: We report here the sequencing and analysis of the genome of the nitrogen-fixing endophyte, Klebsiella pneumoniae 342. Although K. pneumoniae 342 is a member of the enteric bacteria, it serves as a model for studies of endophytic, plant-bacterial associations due to its efficient colonization of plant tissues (including maize and wheat, two of the most important crops in the world), while maintaining a mutualistic relationship that encompasses supplying organic nitrogen to the host plant. Genomic analysis examined K. pneumoniae 342 for the presence of previously identified genes from other bacteria involved in colonization of, or growth in, plants. From this set, approximately one-third were identified in K. pneumoniae 342, suggesting additional factors most likely contribute to its endophytic lifestyle. Comparative genome analyses were used to provide new insights into this question. Results included the identification of metabolic pathways and other features devoted to processing plant-derived cellulosic and aromatic compounds, and a robust complement of transport genes (15.4%), one of the highest percentages in bacterial genomes sequenced. Although virulence and antibiotic resistance genes were predicted, experiments conducted using mouse models showed pathogenicity to be attenuated in this strain. Comparative genomic analyses with the presumed human pathogen K. pneumoniae MGH78578 revealed that MGH78578 apparently cannot fix nitrogen, and the distribution of genes essential to surface attachment, secretion, transport, and regulation and signaling varied between each genome, which may indicate critical divergences between the strains that influence their preferred host ranges and lifestyles (endophytic plant associations for K. pneumoniae 342 and presumably human pathogenesis for MGH78578). Little genome information is available concerning endophytic bacteria. The K. pneumoniae 342 genome will drive new research into this less-understood, but important category of bacterial-plant host relationships, which could ultimately enhance growth and nutrition of important agricultural crops and development of plant-derived products and biofuels.
    PLoS Genetics 07/2008; 4(7):e1000141. DOI:10.1371/journal.pgen.1000141 · 8.17 Impact Factor
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    ABSTRACT: Babesia bovis is an apicomplexan tick-transmitted pathogen of cattle imposing a global risk and severe constraints to livestock health and economic development. The complete genome sequence was undertaken to facilitate vaccine antigen discovery, and to allow for comparative analysis with the related apicomplexan hemoprotozoa Theileria parva and Plasmodium falciparum. At 8.2 Mbp, the B. bovis genome is similar in size to that of Theileria spp. Structural features of the B. bovis and T. parva genomes are remarkably similar, and extensive synteny is present despite several chromosomal rearrangements. In contrast, B. bovis and P. falciparum, which have similar clinical and pathological features, have major differences in genome size, chromosome number, and gene complement. Chromosomal synteny with P. falciparum is limited to microregions. The B. bovis genome sequence has allowed wide scale analyses of the polymorphic variant erythrocyte surface antigen protein (ves1 gene) family that, similar to the P. falciparum var genes, is postulated to play a role in cytoadhesion, sequestration, and immune evasion. The approximately 150 ves1 genes are found in clusters that are distributed throughout each chromosome, with an increased concentration adjacent to a physical gap on chromosome 1 that contains multiple ves1-like sequences. ves1 clusters are frequently linked to a novel family of variant genes termed smorfs that may themselves contribute to immune evasion, may play a role in variant erythrocyte surface antigen protein biology, or both. Initial expression analysis of ves1 and smorf genes indicates coincident transcription of multiple variants. B. bovis displays a limited metabolic potential, with numerous missing pathways, including two pathways previously described for the P. falciparum apicoplast. This reduced metabolic potential is reflected in the B. bovis apicoplast, which appears to have fewer nuclear genes targeted to it than other apicoplast containing organisms. Finally, comparative analyses have identified several novel vaccine candidates including a positional homolog of p67 and SPAG-1, Theileria sporozoite antigens targeted for vaccine development. The genome sequence provides a greater understanding of B. bovis metabolism and potential avenues for drug therapies and vaccine development.
    PLoS Pathogens 11/2007; 3(10):1401-13. DOI:10.1371/journal.ppat.0030148 · 8.06 Impact Factor
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    ABSTRACT: Dichelobacter nodosus causes ovine footrot, a disease that leads to severe economic losses in the wool and meat industries. We sequenced its 1.4-Mb genome, the smallest known genome of an anaerobe. It differs markedly from small genomes of intracellular bacteria, retaining greater biosynthetic capabilities and lacking any evidence of extensive ongoing genome reduction. Comparative genomic microarray studies and bioinformatic analysis suggested that, despite its small size, almost 20% of the genome is derived from lateral gene transfer. Most of these regions seem to be associated with virulence. Metabolic reconstruction indicated unsuspected capabilities, including carbohydrate utilization, electron transfer and several aerobic pathways. Global transcriptional profiling and bioinformatic analysis enabled the prediction of virulence factors and cell surface proteins. Screening of these proteins against ovine antisera identified eight immunogenic proteins that are candidate antigens for a cross-protective vaccine.
    Nature Biotechnology 06/2007; 28(5):569-75. DOI:10.1038/nbt1302 · 39.08 Impact Factor
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    ABSTRACT: Synopsis Soil systems contain the greatest diversity of microorganisms on earth, with 5,000–10,000 species of microorganism per gram of soil. Arthrobacter sp. strains have a primitive life cycle and are among the most frequently isolated, indigenous soil bacteria, found in common and deep subsurface soils, arctic ice, and environments contaminated with industrial chemicals and radioactive materials. To better understand how these bacteria survive in environmentally harsh conditions, the authors used a structural genomics approach to identify genes involved in soil survival of Arthrobacter aurescens strain TC1, a bacterium originally isolated for its ability to degrade the herbicide atrazine. They found that the genome of this bacterium comprises a single circular chromosome and two plasmids that encode for a large number proteins involved in stress responses due to starvation, desiccation, oxygen radicals, and toxic chemicals. A. aurescens' metabolic versatility is in part due to the presence of duplicated catabolic genes and its ability to funnel plasmid-derived intermediates into chromosomally encoded pathways. Arthrobacter's array of genes that allow for survival in stressful conditions and its ability to produce a temperature-tolerant “cyst”-like resting cell render this soil microorganism able to survive and prosper in a variety of environmental conditions.
    PLoS Genetics 01/2007; 2(12):e214. DOI:10.1371/journal.pgen.0020214 · 8.17 Impact Factor
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    ABSTRACT: The dimorphic prosthecate bacteria (DPB) are alpha-proteobacteria that reproduce in an asymmetric manner rather than by binary fission and are of interest as simple models of development. Prior to this work, the only member of this group for which genome sequence was available was the model freshwater organism Caulobacter crescentus. Here we describe the genome sequence of Hyphomonas neptunium, a marine member of the DPB that differs from C. crescentus in that H. neptunium uses its stalk as a reproductive structure. Genome analysis indicates that this organism shares more genes with C. crescentus than it does with Silicibacter pomeroyi (a closer relative according to 16S rRNA phylogeny), that it relies upon a heterotrophic strategy utilizing a wide range of substrates, that its cell cycle is likely to be regulated in a similar manner to that of C. crescentus, and that the outer membrane complements of H. neptunium and C. crescentus are remarkably similar. H. neptunium swarmer cells are highly motile via a single polar flagellum. With the exception of cheY and cheR, genes required for chemotaxis were absent in the H. neptunium genome. Consistent with this observation, H. neptunium swarmer cells did not respond to any chemotactic stimuli that were tested, which suggests that H. neptunium motility is a random dispersal mechanism for swarmer cells rather than a stimulus-controlled navigation system for locating specific environments. In addition to providing insights into bacterial development, the H. neptunium genome will provide an important resource for the study of other interesting biological processes including chromosome segregation, polar growth, and cell aging.
    Journal of Bacteriology 11/2006; 188(19):6841-50. DOI:10.1128/JB.00111-06 · 2.69 Impact Factor

Publication Stats

16k Citations
823.33 Total Impact Points

Institutions

  • 2008–2015
    • J. Craig Venter Institute
      Роквилл, Maryland, United States
  • 2011
    • University of Maryland, Baltimore
      • Institute for Genome Sciences
      Baltimore, Maryland, United States
  • 2009
    • National Center for Biotechnology Information
      Maryland, United States
    • University of Melbourne
      • Department of Microbiology and Immunology
      Melbourne, Victoria, Australia
  • 2000–2007
    • Biomedical Research Institute, Rockville
      Роквилл, Maryland, United States
  • 2002–2006
    • George Washington University
      Washington, Washington, D.C., United States