50nm-scale localization of single unmodified, isotopically enriched, proteins in cells.

Imaging single proteins within cells is challenging if the possibility of artefacts due to tagging or to recognition by antibodies is to be avoided. It is generally believed that the biological properties of proteins remain unaltered when (14)N isotopes are replaced with (15)N. (15)N-enriched proteins can be localised by dynamic Secondary Ion Mass Spectrometry (D-SIMS).

Sensor potency of the moonlighting enzyme-decorated cytoskeleton: the cytoskeleton as a metabolic sensor.

Background: There is extensive evidence for the interaction of metabolic enzymes with the eukaryotic cytoskeleton. The significance of these interactions is far from clear.

Presentation Of The Hypothesis: In the cytoskeletal integrative sensor hypothesis presented here, the cytoskeleton senses and integrates the general metabolic activity of the cell.

Hybolites: novel therapeutic tools for targeting hyperstructures in bacteria.

The scarcity of new molecules that can act on bacteria is a major problem. New strategies for developing such molecules might be based on recent concepts in microbiology. Hyperstructures are large assemblies of molecules and macromolecules that perform functions such as DNA replication, RNA degradation and chemotaxis and the interactions between hyperstructures have been proposed to constitute an intermediate level of organisation in cells.

Chemical microscopy of biological samples by dynamic mode secondary ion mass spectrometry.

3D chemical microscopy is one of the emerging applications of secondary ion mass spectrometry (SIMS) in biology. Tissues, cells, extracellular matrices, and polymer films can be imaged at present with a lateral resolution of 50 nm and depth resolution of 1 nm using the latest generation of CAMECA magnetic sector NanoSIMS 50 or with a lower lateral resolution (above 100 nm) using IMS 4f Cameca SIMS equipped with cold stage. Dynamic mode SIMS analysis is performed in ultrahigh vacuum and thus requires specific and careful preparation of biological samples aimed at preserving and minimizing destruction of the original structural and chemical properties of the samples.

Method for macromolecular colocalization using atomic recombination in dynamic SIMS.

Localizing two or more components of assemblies in biological systems requires both continued development of fluorescence techniques and invention of entirely new techniques. Candidates for the latter include dynamic secondary ion mass spectrometry (D-SIMS). The latest generation of D-SIMS, the Cameca NanoSIMS 50, permits the localization of specific, isotopically labeled molecules and macromolecules in sections of biological material with a resolution in the tens of nanometers and with a sensitivity approaching in principle that of a single protein.