Discovering neuropeptides in Caenorhabditis elegans by two dimensional liquid chromatography and mass spectrometry

Comprehensive multi-dimensional liquid chromatographic separation in biomedical and pharmaceutical analysis: a review

'Multi-dimensional' liquid separations have a history almost as long as chromatography. In multi-dimensional chromatography the sample is subjected to more than one separation mechanism; each mechanism is considered an independent separation dimension. The separations can be carried out either offline via fraction collection, or directly coupled online. Early multi-dimensional separations using combinations of paper chromatography, electrophoresis and gels, in both planar and columnar modes are reviewed. Developments in HPLC have increased the number of measurable analytes in ever more complex matrices, and this has led to the concept of 'global metabolite profiling'. This review focuses on the theory and practice of modern 'comprehensive' multi-dimensional liquid chromatography when applied to biomedical and pharmaceutical analysis.

Molecular characterization of two G protein-coupled receptor splice variants as FLP2 receptors in Caenorhabditis elegans

Two alternatively spliced Caenorhabditis elegans G protein-coupled receptors, T19F4.1a and T19F4.1b, were cloned and functionally characterized. The T19F4.1b receptor protein is 30 amino acids longer than T19F4.1a, and the difference in amino acid constitution is exclusively conferred to the intracellular C-terminal region, suggesting a potential difference in G protein-coupling specificity. Following cloning of the receptor cDNAs into the pcDNA3 vector and stable or transient transfection into Chinese hamster ovary cells, the aequorin bioluminescence/Ca2+ assay was used to investigate receptor activation. This is the first report of the construction of a cell line stably expressing a C. elegans neuropeptide receptor. Our experiments identified both receptors as being cognate receptors for two FMRFamide-related peptides encoded by the flp-2 precursor: SPREPIRFamide (FLP2-A) and LRGEPIRFamide (FLP2-B). Pharmacological profiling using truncated forms of FLP2-A and -B revealed that the active core of both peptides is EPIRFamide. Screening of peptides encoded by other flps did not result in a significant activation of the receptor. In contrast to other C. elegans receptors tested in heterologous expression systems, the functional activation of both T19F4.1a and T19F4.1b was not temperature-dependent. Screening in cells lacking the promiscuous Galpha16 suggests that T19F4.1a and b are both linked to the Gq pathway.