An in vivo imaging-based assay for detecting protein interactions over a wide range of binding affinities.

Identifying and characterizing protein interactions are fundamental steps toward understanding and modeling biological networks. Methods that detect protein interactions in intact cells rather than buffered solutions are likely more relevant to natural systems since molecular crowding events in the cytosol can influence the diffusion and reactivity of individual proteins. One in vivo, imaging-based method relies on the colocalization of two proteins of interest fused to DivIVA, a cell division protein from Bacillus subtilis, and green fluorescent protein (GFP).

Evaluation of affinity-tagged protein expression strategies using local and global isotope ratio measurements.

Elucidation of protein-protein interactions can provide new knowledge on protein function. Enrichments of affinity-tagged (or "bait") proteins with interaction partners generally include background, nonspecific protein artifacts. Furthermore, in vivo bait expression may introduce additional artifacts arising from altered physiology or metabolism.

A general system for studying protein-protein interactions in Gram-negative bacteria.

One of the most promising methods for large-scale studies of protein interactions is isolation of an affinity-tagged protein with its in vivo interaction partners, followed by mass spectrometric identification of the copurified proteins. Previous studies have generated affinity-tagged proteins using genetic tools or cloning systems that are specific to a particular organism. To enable protein-protein interaction studies across a wider range of Gram-negative bacteria, we have developed a methodology based on expression of affinity-tagged "bait" proteins from a medium copy-number plasmid.

Zea mays assays of chemical/radiation genotoxicity for the study of environmental mutagens.

From a literature survey, 86 chemicals are tabulated that have been evaluated in 121 assays for their clastogenic effects in Zea mays. Eighty-one of the 86 chemicals are reported as giving a positive reaction (i.e.

Molecular photovoltaics and the photoactivation of mammalian cells.

Photosynthetic reaction centers are integral plant membrane protein complexes and molecular photovoltaic structures. We report here that addition of Photosystem I (PSI)-proteoliposomes to retinoblastoma cells imparts photosensitivity to these mammalian cells, as demonstrated by light-induced movement of calcium ions. Control experiments with liposomes lacking PSI demonstrated no photosensitivity.

Lycopersicon assays of chemical/radiation genotoxicity for the study of environmental mutagens.

From a literature survey, 21 chemicals are tabulated that have been evaluated in 39 assays for their clastogenic effects in Lycopersicon. Nineteen of the 21 chemicals are reported as giving a positive reaction (i.e.