Biomedical subjects

Bret Cooper

Publications and source records attributed to Bret Cooper.

8 recordsLinked to original sources

PubMed2006

Alternative workflows for plant proteomic analysis.

High-throughput separations are intrinsic to the detection and analysis of peptides and proteins by mass spectrometry (MS). Together, efficient separation and MS can lead to the identification of thousands of proteins in a sample, cell or tissue and help build proteome maps that can be used to define a cell type or cellular state. Although 2D gels have been successfully used to separate proteins for subsequent MS analysis, alternative separation efficiencies and, consequently deeper results could be obtained with HPLC or other separation techniques that improve throughput. This highlight is aimed toward plant scientists who have special separation needs due to the nature of plant cells and who could benefit from knowing options and requirements for adopting alternative separation protocols. Through the various sample processing and protein separation strategies, plant biologists should be able to improve the quality of their proteomic reference maps and gain new information about the proteins that define plant cells.

Chromatography, High Pressure Liquid↗

PubMed2006

Shotgun identification of proteins from uredospores of the bean rust Uromyces appendiculatus.

We are interested in learning more about the proteome of Uromyces appendiculatus, the fungus that causes common bean rust. Knowledge of the proteins that differentiate life-cycle stages and distinguish infectious bodies such as uredospores, germlings, appressoria, and haustoria may be used to define host-pathogen interactions or serve as targets for chemical inhibition of the fungus. We have used 2-D nanoflowLC-MS/MS to identify more than 400 proteins from asexual uredospores. A majority of the proteins appear to have roles in protein folding or protein catabolism. We present a model by which an abundance of heat shock proteins and translation elongation factors may enhance a spore's ability to survive environmental stresses and rapidly initiate protein production upon germination.

Amino Acid Sequence↗

PubMed2006

Mass spectrometry-based proteomics for the detection of plant pathogens.

Plant diseases caused by fungi, oomycetes, viruses, and bacteria are devastating both to the economy and to the food supply of a nation. Therefore, the development of new, rapid methods to identify these pathogens is a highly important area of research that is of international concern. MS-based proteomics has become a powerful and increasingly popular approach to not only identify these pathogens, but also to better understand their biology. However, there is a distinction between identifying a pathogen protein and identifying a pathogen based upon the detection of one of its proteins and this must be considered before the general application of MS for plant pathogen detection is made. There has been a recent push in the proteomics community to make data from large-scale proteomics experiments publicly available in the form of a centralized repository. Such a resource could enable the use of MS as a universal plant pathogen detection technology.

Bacterial Proteins↗

PubMed2003

A network of rice genes associated with stress response and seed development.

We used a systematic approach to build a network of genes associated with developmental and stress responses in rice by identifying interaction domains for 200 proteins from stressed and developing tissues, by measuring the associated gene expression changes in different tissues exposed to a variety of environmental, biological, and chemical stress treatments, and by localizing the cognate genes to regions of stress-tolerance trait genetic loci. The integrated data set suggests that similar genes respond to environmental cues and stresses, and some may also regulate development. We demonstrate that the data can be used to correctly predict gene function in monocots and dicots. As a result, we have identified five genes that contribute to disease resistance in Arabidopsis.

14-3-3 Proteins↗

PubMed2003

Investigative proteomics: identification of an unknown plant virus from infected plants using mass spectrometry.

We describe the identification of a previously uncharacterized plant virus that is capable of infecting Nicotiana spp. and Arabidopsis thaliana. Protein extracts were first prepared from leaf tissue of uninfected tobacco plants, and the proteins were visualized with two-dimensional electrophoresis (2-DE). Matching gels were then run using protein extracts of a tobacco plant infected with tobacco mosaic virus (TMV). After visual comparison, the proteins spots that were differentially expressed in infected plant tissues were cut from the gels and analyzed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Tandem mass spectrometry data of individual peptides was searched with SEQUEST. Using this approach we demonstrated a successful proof-of-concept experiment by identifying TMV proteins present in the total protein extract. The same procedure was then applied to tobacco plants infected with a laboratory viral isolate of unknown identity. Several of the differentially expressed protein spots were identified as proteins of potato virus X (PVX), thus successfully identifying the causative agent of the uncharacterized viral infection. We believe this demonstrates that HPLC-MS/MS can be used to successfully characterize unknown viruses in infected plants.

Amino Acid Sequence↗

PubMed2003

Identification of rice (Oryza sativa) proteins linked to the cyclin-mediated regulation of the cell cycle.

Yeast two-hybrid assays were used to identify rice proteins interacting with two rice cyclins and other proteins potentially involved in cell cycling. The DNA sequences encoding 119 protein fragments identified were then compared by BLAST against proteins in GenBank. The proteins found include myosin-like proteins, transcription factors, kinesins, centromere proteins and undefined proteins. Based on interactions with cyclins and other elements required for cycling, we believe the undefined proteins may be involved in associated cycling processes. The identification of proteins involved in cell cycle regulation in rice may allow for the control of agronomic traits involving plant growth or development.

Cell Cycle↗

PubMed2003

Diverse RNA viruses elicit the expression of common sets of genes in susceptible Arabidopsis thaliana plants.

Systemic infections of plants by viruses require that viruses modify host cells in order to facilitate infections. These modifications include induction of host factors required for replication, propagation and movement, and suppression of host defense responses, which are likely to be associated with changes in host gene expression. Past studies of the effects of viral infection on gene expression in susceptible hosts have been limited to only a handful of genes. To gain broader insight into the responses elicited by viruses in susceptible hosts, high-density oligonucleotide probe microarray technology was used. Arabidopsis leaves were either mock inoculated or inoculated with cucumber mosaic cucumovirus, oil seed rape tobamovirus, turnip vein clearing tobamovirus, potato virus X potexvirus, or turnip mosaic potyvirus. Inoculated leaves were collected at 1, 2, 4, and 5 days after inoculation, total RNA was isolated, and samples were hybridized to Arabidopsis GeneChip microarrays (Affymetrix). Microarray hybridization revealed co-ordinated changes in gene expression in response to infection by diverse viruses. These changes include virus-general and virus-specific alterations in the expression of genes associated with distinct defense or stress responses. Analyses of the promoters of these genes further suggest that diverse RNA viruses elicit common responses in susceptible plant hosts through signaling pathways that have not been previously characterized.

Arabidopsis↗

PubMed2002

A draft sequence of the rice genome (Oryza sativa L. ssp. japonica).

The genome of the japonica subspecies of rice, an important cereal and model monocot, was sequenced and assembled by whole-genome shotgun sequencing. The assembled sequence covers 93% of the 420-megabase genome. Gene predictions on the assembled sequence suggest that the genome contains 32,000 to 50,000 genes. Homologs of 98% of the known maize, wheat, and barley proteins are found in rice. Synteny and gene homology between rice and the other cereal genomes are extensive, whereas synteny with Arabidopsis is limited. Assignment of candidate rice orthologs to Arabidopsis genes is possible in many cases. The rice genome sequence provides a foundation for the improvement of cereals, our most important crops.

Arabidopsis↗