NIH Proteomics Interest Group

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ProtIG is an NIH Special Interest Group (SIG) that organizes seminars and workshops in relevant areas of proteomics, including talks on separation and protein identification methods, determination of post-translational modifications, protein-protein interactions, and bioinformatics and data management. A monthly seminar series is held at 10am usually on the first Thursday of each month (always check the Mtgs/Seminars button on this page for these and other PROTIG announced meetings). To receive email announcements of ProtIG events, join the listserv (Join the SIG button on this page)

February ProtIG Seminar
February 5, 2016
9:30am - 10:30pm
Building 50, NIH Campus
Room 1328/1334 (Rear)
Akos Vertes, Ph.D.
Professor of Chemistry
Professor of Biochemistry and Molecular Biology
Founder and Co-Director of the W. M. Keck Institute for Proteomics Technology and Applications
The George Washington University

"New Approaches for Microbial Susceptibility Testing and the Analysis of the Human Cell Cycle"

Metabolism in microbial colonies responds to competing species, rapidly evolving genetic makeup, and sometimes dramatic environmental changes. Conventional characterization of the existing and emerging microbial strains and their interactions with antimicrobial agents, e.g., the Kirby-Bauer susceptibility test, relies on time consuming methods with limited ability to discern the molecular mechanism. Assessing the metabolic adaptation of microbial colonies requires their non-targeted molecular imaging in a native environment. Laser ablation electrospray ionization (LAESI) is an ambient ionization technique that in combination with mass spectrometry (MS) enables the rapid analysis and molecular imaging of over 400 metabolites and lipids. In the first part of this presentation, we report on the application of LAESI-MS imaging to gain a deeper molecular insight into microbe-antibiotic interactions, and enhance the speed and quantitative nature of antibiotic susceptibility testing.

Mitosis in eukaryotic cells is divided into four successive stages, i.e., prophase, metaphase, anaphase, and telophase, based on the distribution of chromosomes and the morphologies of the mitotic spindles. Consumption of ATP during the two stages of anaphase, are thought to be different, i.e., during the movement of the chromosomes towards the two spindle poles (anaphase A) does not require ATP, whereas the elongation of the spindles (anaphase B) proceeds with ATP consumption. However, the intracellular energy states and metabolic composition during the other mitotic stages, e.g., metaphase, and the following cytokinesis have not been characterized. Recent advances in capillary microsampling mass spectrometry enable the analysis of the metabolic makeup, energy and redox states, and lipid composition of individual cells. Here, we show the changes of energy states, such as adenylate energy charge (AEC), in single cells at distinct mitotic stages. Cellular AEC at metaphase showed the highest level and narrowest distribution. Reduced AEC levels were observed in the anaphase, telophase, and cytokinesis. These findings might be linked to the consumption of ATP in spindle elongation during late anaphase and telophase. The [GTP]/[GDP] ratio exhibited higher values in metaphase and decreased in the anaphase and telophase, and rebound during cytokinesis. Our results inform on the dynamic changes of cellular physiological states and the corresponding metabolic noise during the movement of chromosomes and elongation of spindles in mitosis.

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Seminars will be webcast online at and available on the
Proteomics Interest Group website as an archived presentation unless otherwise noted.

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This site was updated on January 29th, 2016. Please contact Renee Olano at olanol(at) with questions or suggestions.