Last updated on Wednesday, March 30, 2016
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Name : David A Christopher
Title : Professor/Chair
Unit : Department of Molecular Biosciences & BioEngineering
Address : 1955 East-West Rd. #218
Honolulu, HI 96822
Room : Ag Sciences Building 415B
Phone : (808)956-8550
Fax : (808)956-3542
E-mail : email@example.com
Website : http://www.ctahr.hawaii.edu/site/Bio.aspx?ID=CHRISDAV
Specialties : Plant molecular and cellular biology, photosynthesis, genomics, regulation of secretory proteins, biotechnology, plant productivity, creating pest and disease resistance in crops such as papaya, pineapple and anthurium.
University of New Hampshire (B.S. Plant Science)
Weizmann Institute of Science (M.S. Plant Genetics)
University of Arizona (Ph.D. Molecular and Cellular Biology)
Texas A & M University (Post-doctoral research in Biochemistry and Biophysics)
Minor Crops Papaya Pests and Diseases, USDA-Research Services
"Bioengineering Papaya for Resistance to Phytophthora palmivora”
National Science Foundation, MCB-Cellular Biology Program
"Functional genomics of the protein disulfide isomerase gene family: Unraveling protein folding and redox-regulatory networks".
National Science Foundation, Major Research Instrumentation.
"Acquisition of Instrumentation for Transmission Electron Microscopy at the University of Hawaii"
USDA-Research Services Papaya Pests and Diseases, USDA-Research Services
“Characterization and Cloning of Pathogen-Inducible Genes and Promoters to Improve Resistance of Papaya to Fungal Disease”
MBBE 304 Biotechnology: Science and Ethical Issues (3 credits)
Introduction to the concepts, goals, socio-ethical issues, controversies, and consequences of biotechnology using real-life case studies of cloning, GMO foods, DNA fingerprinting, gene therapy, genetic engineering and pharmaceuticals. (Cross-listed as BIOL 304); Pre: BIOL 171 (concurrent) or consent.
MBBE 620 Plant Biochemistry (3 credits)
Comprehensive study of chemical constituents and biochemical processes unique to the plant kingdom with emphasis on selected aspects of current interest. Pre: MBBE 402 or consent.
Research Interests :
My lab's research emphasizes two general areas: 1) basic research exploring the function of plant cells at the molecular level; and 2) the application of plant biotechnology to solve practical problems faced by local agriculture. In the first area, we are elucidating the intriguing molecular mechanisms that regulate plant productivity, nutrient transport, secretory protein synthesis and protein folding. We use a combination of molecular, cellular, biochemical and genetic approaches applied to the genetically amenable model plant, Arabidopsis thaliana. We have identified a potassium channel required for the uptake of potassium by plant cells and for providing tolerance to salinity and heavy metal stress. The channel protein is regulated by calmodulin and is a member of the CNGC (cyclic nucleotide gated channel) family.
We are also studying secretory protein synthesis and folding in the endoplasmic reticulum (ER) mediated by a class of enzymes designated protein disulfide isomerases (PDI). We have found that PDIs play roles in the accumulation of proteins in seeds, the nutritional value of grain, and the secretory trafficking of proteins to other compartments in plants. We have used a PDI-specific antiserum, electron microscopy and immunolabeling as well as green fluorescent protein fused to PDIs, to localize the proteins to sub-cellular membranes and organelles of leaf, embryo and root cells. We have found PDIs in the ER, vacuole, chloroplast, golgi and apoplasm. Reverse genetics are being used to identify the phenotypes of PDI knockouts. Yeast-two hybrid analyses and fluorescence resonance energy transfer (FRET) experiments are used to identify and study proteins that interact with PDIs. Complementation of protein folding mutants of E. coli and yeast and protein folding assays distinguish between isomerase, reduction and oxidation functions.
In the second area of research, our primary goals are to decrease the use of pesticides in agriculture by developing prest and disease resistant plants. We contribute the tools of molecular biology in collaborative research that uses biotechnology to improve anthuriums, papaya, and pineapple. In papaya, we are developing plants that are resistant to the pathogen, Phytophthora palmivora. In Anthuriums, we investigate the genetic manipulation of aging and senescence. In pineapple, we study the biochemistry of protease inhibitors. A genomics approach is being used to isolate and characterize comprehensive sets of tissue-specific genes from tropical fruit crops. Detailed expression and regulation analyses and tissue-specific promoter isolation are being undertaken.
Our lab also sponsors the Advances in Bioscience Education (ABE) workshop funded by the National Science Foundation grant. This summer program brings community college faculty and students together to gain hands-on experience in real biology research. They work as teams on experimental problems using state-of-the-art molecular biological, bioinformatic, cellular, genomic and biochemical approaches.
Selected Recent Publications :
Yuen, C.Y.L, Wong, K., Christopher, D.A. (2016) Phylogenetic characterization and promoter expression analysis of a novel hybrid protein disulfide isomerase/cargo receptor subfamily unique to plants and chromalveolates. Molecular Genetics & Genomics. 291:455-469
- Teixeira da Silva, J.A., Dobranszki, J., Zeng, S.J. , Winarto, B., Lennon, A.M., Jaufeerally-Fakim, Y., Christopher, D.A. (2015) Genetic transformation and molecular research in Anthurium: progress and prospects. Plant Cell Tissue and Organ Culture, 123:205–219
- Hilario, L.C., Shimshock, R., Ng, Cheryl, Bingham, J.-P., Christopher, D.A. (2015) Screening Carica papaya native promoters driving stilbene synthase expression in Arabidopsis thaliana for resveratrol glucoside (piceid) synthesis. Plant Biotechnology Reports, 9: 307-317.
- Porter, B.W., Yuen, C.Y.L, Christopher, D.A. (2015) Dual protein trafficking to secretory and non-secretory cell compartments: Clear or double vision? Plant Science. 234: 174-179.
- Hilario, L.C., Christopher, D.A. (2015) Improved Agrobacterium-mediated transformation of Carica papaya cultivar ‘Kapoho’ from embryogenic cell suspension cultures. In Vitro Cellular & Developmental Biology-Plant, http://dx.doi.org/10.1007/s11627-015-9719-4.
- Porter, B.P., Christopher, D.A. and Zhu, Y.J. (2014) Genomics of Papaya Disease Resistance. In: Genetics and Genomics of Papaya. Ming R and Moore PH (eds). Springer Science and Business Media, New York.
- Hilario, L.C., Porter, B.W., Zhu, Y.J., Christopher, D.A. (2014) Identification and Characterization of Papaya (Carica papaya, L.) Promoters by Heterologous Expression as eGFP Fusions in Arabidopsis thaliana. Tropical Plant Biology 7:85-99.
- Yuen, C.Y.L, Matsumoto, K.O., Christopher, D.A. (2013) Variation in the subcellular localization and protein folding activity among Arabidopsis thaliana homologs of protein disulfide isomerase. Biomolecules, 3:848-869.
- Yuen, C.Y.L, Christopher, D.A. (2013) The group IV-A cyclic nucleotide-gated channels, CNGC19 and CNGC20, localize to the vacuole membrane in A. thaliana. Annals Botany Plants 5: 10.1093/aobpla/plt012
- Cho, E.J., Yuen, C.Y., Kang, B-H.,Ondzighi, C., Staehelin, L. A., Christopher, D.A. (2011) Protein disulfide isomerase-2 of Arabidopsis mediates protein folding and localizes to both the secretory pathway and nucleus, where it interacts with maternal effect embryo arrest factor. Molecules and Cells, 32:459-75.
- Yuen, C.Y.L and Christopher, D.A. (2010) The role of cyclic nucleotide-gated channels in cation nutrition and abiotic stress. (In: “Ion Channels and Plant Stress Responses, V. Demidchik & F. Maathuis eds), Springer-Verlag, Berlin-Heidelberg, Germany, pp. 137-158.
- Guo, K.M., Babourina, O., Christopher, D.A., Borsics, T., Rengel, Z. (2010) The cyclic nucleotide-gated channel AtCNGC10 transports Ca2+ and Mg2+ in Arabidopsis. Physiologia Plantarum 139:303-312.
- Neuteboom L.W., Matsumoto K.O., Christopher D.A. (2009) An extended AE-rich N-terminal trunk in secreted pineapple cystatin enhances inhibition of fruit bromelain and is post-translationally removed during ripening. Plant Physiology 151: 515-527 (Cover Feature).
- Porter B.W., Zhu Y.J., Christopher D.A. (2009) Carica papaya genes regulated by Phytophthora palmivora: A new system for comparative genomics. Tropical Plant Biology 2: 84–97.
- Porter B.W., Zhu Y.J., Webb D.T., Christopher D.A. (2009) Novel thigmomorphogenetic responses in Carica papaya: Touch decreases anthocyanin levels and stimulates petiole cork outgrowths. Annals of Botany, 103: 847-858.
- C.A. Ondzighi, Christopher, D.A., Cho, E.J., Chang, S.C., Staehelin, L.A. (2008) Arabidopsis Protein Disulfide Isomerase-5 Inhibits Cysteine Proteases during Trafficking to Vacuoles before Programmed Cell Death of the Endothelium in Developing Seeds. The Plant Cell, 20: 2205-2220.
- D.-P. Lu,Christopher, D.A. (2008) Light enhances the unfolded protein response as measured by BiP2 gene expression and the secretory GFP-2SC marker in Arabidopsis. Physiologia Plantarum, 134: 360–368.
- D.-P. Lu, Christopher,D.A. (2008) Endoplasmic reticulum stress activates the expression of a sub-group of protein disulfide isomerase genes and AtbZIP60 modulates the response in Arabidopsis thaliana. Molecular Genetics & Genomics. 280:199-210.
- B.W. Porter, K.S. Aizawa, Y.J. Zhu, Christopher D.A. (2008) Differentially expressed and new non-protein-coding genes from Carica papaya root transcriptome survey. Plant Science, 174:38-50.R. Ming et al. (2008) Genome of the transgenic tropical fruit tree papaya (Carica papaya L.) Nature 452:991-995.
- D. A. Christopher, Borsics T., Yuen C.Y.L., Ullmer W., Andème-Ondzighi C., Andres M.L., Kang B.H., Staehelin L.A. 2007. The cyclic nucleotide-gated cation channel AtCNGC10 traffics from the ER via Golgi vesicles to the plasma membrane of Arabidopsis root and leaf cells. Biomedical Central Plant Biology 7(48): 1471-2229.
- T. Borsics,Webb D., Ondzighi C., Staehelin L.A., and Christopher DA2007. The cyclic nucleotide-gated calmodulin-binding channel AtCNGC10 localizes to the plasma membrane and influences numerous growth responses and starch accumulation in Arabidopsis thaliana. Planta 225: 563 - 573.
- T.S.L. Lau, E. Eno, G. Goldstein, C. Smith, D.A. Christopher. 2006. Ambient levels of UV-B in Hawaii combined with nutrient deficiency decrease photosynthesis in near-isogenic maize lines varying in leaf flavonoids:Flavonoids decrease photoinhibition in plants exposed to UV-B. Photosynthetica, 44: 394-403.
- D.-P. Lu and D.A. Christopher.2006. Immunolocalization of a protein disulfide isomerase to Arabidopsis thaliana chloroplasts and its association with starch biogenesis. International J. Plant Sciences 167(1): 1-9.
- X.L. Li, T. Borsics, H.M. Harrington, D.A. Christopher. 2005.Arabidopsis AtCNGC10 rescues potassium channel mutants of E. coli, yeast and Arabidopsis and is regulated by calcium/calmodulin and cyclic GMP in E. coli.Functional Plant Biology, 32:643-653.