Galbraith, D. W. (2003). Global analysis of cell type-specific gene expression. Comparative and Functional Genomics, 4(2), 208-215.
PMID: 18629131;PMCID: PMC2447418;Abstract:
The tissues and organs of multicellular eukaryotes are frequently observed to comprise complex three-dimensional interspersions of different cell types. It is a reasonable assumption that different global patterns of gene expression are found within these different cell types. This review outlines general experimental strategies designed to characterize these global gene expression patterns, based on a combination of methods of transgenic fluorescent protein (FP) expression and targeting, of flow cytometry and sorting and of high-throughput gene expression analysis. Copyright © 2003 John Wiley & Sons, Ltd.
Galbraith, D. W. (2006). The daunting process of MIAME [2]. Nature, 444(7115), 31-.
Chen, S. C., Cannon, C. H., Kua, C. S., Liu, J. J., & Galbraith, D. W. (2014). Genome size in the Fagaceae and its general implications for trees.. Tree Genetics and Genomics, 10(4), 977-988.
AbstractPolyploidization is a major source of diversification among plants, particularly during cladogenesis, but most evidence involves herbaceous temperate species. The prevalence of polyploidy among woody taxa is largely unknown, especially among tropical groups. In this study, we examined genome size variation globally and at several taxonomic levels within the Fagaceae. This family has diversified in the northern temperate zone (Quercus) and at least twice in the Asian tropics (Lithocarpus and Castanopsis), allowing us to examine genomic size evolution across a broad latitudinal range. We compared nuclear DNA contents from 78 species in six genera, including new measurements for 171 individuals from 47 Chinese species using standard flow cytometry methods. No evidence suggests that polyploidization or whole genome duplication has occurred in the family. Genome size varied among genera, but limited variation was present in each genus and species. In general, tropical species had larger genomes than temperate species, but the ancestral state cannot be determined given current evidence. Partial duplication does seem to occur among species as within genus variation was larger than within species variation. A review of the literature suggests that genome size and even chromosome structure is highly conserved among woody plants and trees. We propose that ploidy level and genome size are conserved among trees because they participate in diverse syngameons. This behavior would provide similar benefits to polyploidization but avoid exclusion from the syngameon. This conservatism in genome size and structure should enhance ongoing whole genome studies.
Grebenok, R. J., Galbraith, D. W., Benveniste, I., & Feyereisen, R. (1996). Ecdysone 20-monooxygenase, a cytochrome P450 enzyme from spinach, Spinacia oleracea. Phytochemistry, 42(4), 927-933.
Abstract:
A microsomal preparation isolated from first leaves of 25-day-old spinach catalysed the hydroxylation of ecdysone to produce the insect moulting hormone, 20-hydroxyecdysone. Hydroxylation was dependent on NADPH and molecular oxygen, and was inhibited by carbon monoxide. Carbon monoxide inhibition was partially reversible by white light. Polyclonal antibodies to the Jerusalem artichoke NADPH-cytochrome P450 reductase inhibited the hydroxylation reaction as well as the spinach microsomal NADPH cytochrome c reductase. These results taken together establish ecdysone hydroxylation as a cytochrome P450 dependent reaction in spinach, which is known to synthesize large amounts of phytoecdysteroids.
Song, C., Guo, Y., Qiu, Q., Lambert, G., Galbraith, D. W., Jagendorf, A., & Zhu, J. (2004). A probable Na+(K+)/H+ exchanger on the chloroplast envelope functions in pH homeostasis and chloroplast development in Arabidopsis thaliana. Proceedings of the National Academy of Sciences of the United States of America, 101(27), 10211-10216.
PMID: 15220473;PMCID: PMC454189;Abstract:
Electroneutral monovalent cation/proton antiport across the chloroplast envelope has been shown previously to have an important regulatory effect on stromal pH and thereby on photosynthetic carbon reduction. Here we report that an Arabidopsis nuclear gene, AtCHX23, encodes a putative Na+(K +)/H+ exchanger and functions in the adjustment of pH in the cytosol and possibly in maintaining a high pH level in the chloroplast stroma. The AtCHX23 protein is localized in the chloroplast envelope. Plastids from chx23 mutants had straight thylakoids but lacked grana lamellae. chx23 mutant leaves were pale yellow and had a much reduced chlorophyll content. The chlorophyll content of chx23 was increased by growing in medium at low (4.0) pH and decreased by growing at high (7.0) pH. The cytosolic pH in the leaves of the mutant was significantly higher than that in the wild type. chx23 mutants displayed a high sensitivity to NaCl. Together, these data indicate that CHX23 is a probable chloroplast Na+(K+)/H+ exchanger important for pH homeostasis and chloroplast development and function.
