David W Galbraith
Professor, BIO5 Institute
Professor, Biomedical Engineering
Professor, Plant Science
Primary Department
(520) 621-9153
Work Summary
I examine the molecular functions of the different cells found in the tissues and organs of plants and animals and how they combine these functions to optimize the health and vigor of the organism.
Research Interest
David Galbraith obtained undergraduate and graduate degrees in Biochemistry from the University of Cambridge, and postdoctoral training as a NATO Fellow at Stanford University. His first academic appointment was at the University of Nebraska Lincoln, and he became Professor of Plant Sciences at the University of Arizona in 1989. His research has focused on the development of instrumentation and methods for the analysis of biological cells, organs, and systems. He is internationally recognized as a pioneer in the development and use of flow cytometry and sorting in plants, developing widely-used methods for the analysis of genome size and cell cycle status, and for the production of somatic hybrids. He also was among the first to develop methods for the analysis of gene expression within specific cell types, using markers based on Fluorescent Protein expression for flow sorting these cells, and microarray platforms for analysis of their transcriptional activities and protein complements. Current interests include applications of highly parallel platforms for transcript and protein profiling of minimal sample sizes, and for analysis of genetic and epigenetic mechanisms that regulate gene expression during normal development and in diseased states, specifically pancreatic cancer. He is also funded to study factors involved in the regulation of bud dormancy in Vitis vinifera, and has interests in biodiversity and improvement of third-world agriculture. He has published more than 180 scholarly research articles, holds several patents, was elected a Fellow of the American Association for Advancement of Science in 2002, and serves on the editorial board of Cytometry Part A. He is widely sought as a speaker, having presented over 360 seminars in academic, industrial and conference settings. He was elected Secretary of the International Society for Advancement of Cytometry in 2016. Keywords: Plant and Animal Cellular Engineering; Biological Instrumentation; Flow Cytometry and Sorting

Publications

Brown, J. K., Lambert, G. M., Ghanim, M., Czosnek, H., & Galbraith, D. W. (2005). Nuclear DNA content of the whitefly Bemisia tabaci (Aleyrodidae: Hemiptera) estimated by flow cytometry. Bulletin of Entomological Research, 95(4), 309-312.
BIO5 Collaborators
Judith K Brown, David W Galbraith

PMID: 16048678;Abstract:

The nuclear DNA content of the whitefly Bemisia tabaci (Gennnadius) was estimated using flow cytometry. Male and female nuclei were stained with propidium iodide and their DNA content was estimated using chicken red blood cells and Arabidopsis thaliana L. (Brassicaceae) as external standards. The estimated nuclear DNA content of male and female B. tabaci was 1.04 and 2.06 pg, respectively. These results corroborated previous reports based on chromosome counting, which showed that B. tabaci males are haploid and females are diploid. Conversion between DNA content and genome size (1 pg DNA = 980 Mbp) indicate that the haploid genome size of B. tabaci is 1020 Mbp, which is approximately five times the size of the genome of the fruitfly Drosophila melanogaster Meigen. These results provide an important baseline that will facilitate genomics-based research for the B. tabaci complex. © CAB International, 2005.

Jiexun, L. i., Xin, L. i., Hua, S. u., Chen, H., & Galbraith, D. W. (2006). A framework of integrating gene relations from heterogeneous data sources: An experiment on Arabidopsis thaliana. Bioinformatics, 22(16), 2037-2043.
BIO5 Collaborators
Hsinchun Chen, David W Galbraith

PMID: 16820427;Abstract:

One of the most important goals of biological investigation is to uncover gene functional relations. In this study we propose a framework for extraction and integration of gene functional relations from diverse biological data sources, including gene expression data, biological literature and genomic sequence information. We introduce a two-layered Bayesian network approach to integrate relations from multiple sources into a genome-wide functional network. An experimental study was conducted on a test-bed of Arabidopsis thaliana. Evaluation of the integrated network demonstrated that relation integration could improve the reliability of relations by combining evidence from different data sources. Domain expert judgments on the gene functional clusters in the network confirmed the validity of our approach for relation integration and network inference. © 2006 Oxford University Press.

Galbraith, D., Zhang, C., Barthelson, R. A., Lambert, G. M., & Galbraith, D. W. (2008). Global characterization of cell-specific gene expression through fluorescence-activated sorting of nuclei. Plant physiology, 147(1).

We describe a simple and highly effective means for global identification of genes that are expressed within specific cell types within complex tissues. It involves transgenic expression of nuclear-targeted green fluorescent protein in a cell-type-specific manner. The fluorescent nuclei are then purified from homogenates by fluorescence-activated sorting, and the RNAs employed as targets for microarray hybridization. We demonstrate the validity of the approach through the identification of 12 genes that are selectively expressed in phloem.

Galbraith, D., Harkins, K. R., Jefferson, R. A., Kavanagh, T. A., Bevan, M. W., & Galbraith, D. W. (1990). Expression of photosynthesis-related gene fusions is restricted by cell type in transgenic plants and in transfected protoplasts. Proceedings of the National Academy of Sciences of the United States of America, 87(2).

We have analyzed the expression of chimeric genes in populations of protoplasts isolated from the photosynthetic and nonphotosynthetic tissues within leaves of transgenic tobacco plants and separated by fluorescence-activated cell sorting. Expression of transcriptional gene fusions controlled by promoters from photosynthesis-associated genes showed a striking dependence on cell type. These patterns of expression were preserved when the gene fusions were transfected into normal (nontransgenic) tobacco leaf protoplasts.

Galbraith, D. W., Bourque, D. P., & Bohnert, H. J. (1995). Preface. Methods in Cell Biology, 50(C), xxi-xxii.
BIO5 Collaborators
David W Galbraith, Laurence Hurley