Biomedical subjects

Barry G Rolfe

Publications and source records attributed to Barry G Rolfe.

22 records · Page 2Linked to original sources

PubMed2003

Proteomic analysis of wild-type Sinorhizobium meliloti responses to N-acyl homoserine lactone quorum-sensing signals and the transition to stationary phase.

Proteome analysis revealed that two long-chain N-acyl homoserine lactones (AHLs) produced by Sinorhizobium meliloti 1021 induced significant differences in the accumulation of more than 100 polypeptides in early-log-phase cultures of the wild type. Fifty-six of the corresponding proteins have been identified by peptide mass fingerprinting. The proteins affected by addition of these two AHLs had diverse functions in carbon and nitrogen metabolism, energy cycles, metabolite transport, DNA synthesis, and protein turnover. Two hours of exposure to 3-oxo-C(16:1)-homoserine lactone (3-oxo-C(16:1)-HL) affected the accumulation of 40 of the 56 identified proteins, whereas comparable exposure to C(14)-HL affected 13 of the 56 proteins. Levels of four proteins were affected by both AHLs. Exposure to 3-oxo-C(16:1)-HL for 8 h affected the accumulation of 17 proteins, 12 of which had reduced accumulation. Of the 80 proteins identified as differing in accumulation between early-log- and early-stationary-phase cultures, only 13 were affected by exposure to 3-oxo-C(16:1)-HL or C(14)-HL. These results provide a foundation for future studies of the functions regulated by AHL quorum sensing in S. meliloti and help to establish proteomic analysis as a powerful global approach to the identification of quorum-sensing regulatory patterns in wild-type bacteria.

4-Butyrolactone↗

PubMed2003

Proteomics as a functional genomics tool.

To understand the function of all the genes in an organism, one needs to know not only which genes are expressed, when, and where, but also what the protein end products are and under which conditions they accumulate in certain tissues. Proteomics aims at describing the whole protein output of the genome and complements transcriptomic and metabolomic studies. Proteomics depends on extracting, separating, visualizing, identifying, and quantifying the proteins and their interactions present in an organism or tissue at any one time. All of these stages have limitations. Therefore, it is, at present, impossible to describe the whole proteome of any organism. Plants might synthesize many thousands of proteins at one time, and the whole potentially synthesized proteome certainly exceeds the number of estimated genes for that genome. This occurs because the gene products of one gene can differ due to alternative splicing and a variety of possible posttranslational modifications. It is, therefore, essential to optimize every step towards detecting the whole proteome while realizing the limitations. We concentrate here on the most commonly used steps in high-throughput plant proteomics with the techniques we have found most reproducible and with the highest resolution and quality.

Coloring Agents↗

PubMed2003

11th International Congress on Molecular Plant-Microbe Interactions held at St. Petersburg--a report.

The report is a short summary of the most interesting presentations at the 11th International Congress on Molecular Plant-Microbe Interactions held during July 18-27, 2003 at St. Petersburg, Russia. The key elements from several sessions on the legume-Rhizobium interactions have been discussed.

Fabaceae↗

PubMed2002

Evaluation of proteome reference maps for cross-species identification of proteins by peptide mass fingerprinting.

We tested whether proteome reference maps established for one species can be used for cross-species protein identification by comparing two-dimensional protein gel patterns and protein identification data of two closely related bacterial strains and four plant species. First, proteome profiles of two strains of the fully sequenced bacterium Sinorhizobium meliloti were compared as an example of close relatedness, high reproducibility and sequence availability. Secondly, the proteome profiles of three legumes (Medicago truncatula, Melilotus alba and Trifolium subterraneum), and the nonlegume rice (Oryza sativa) were analysed to test cross-species similarities. In general, we found stronger similarities in gel patterns of the arrayed proteins between the two bacterial strains and between the plant species than could be expected from the sequence similarities. However, protein identity could not be concluded from their gel position, not even when comparing strains of the same species. Surprisingly, in the bacterial strains peptide mass fingerprinting was more reliable for species-specific protein identification than N-terminal sequencing. While peptide masses were found to be unreliable for cross-species protein identification, we present useful criteria to determine confident matching against species-specific expressed sequence tag databases. In conclusion, we present evidence that cautions the use of proteome reference maps and peptide mass fingerprinting for cross-species protein identification.

Electrophoresis, Gel, Two-Dimensional↗