Neuropeptides, critical brain peptides that modulate animal behavior by affecting the activity of almost every neuronal circuit, are inherently difficult to predict directly from a nascent genome sequence because of extensive posttranslational processing. The combination of bioinformatics and proteomics allows unprecedented neuropeptide discovery from an unannotated genome. Within the Apis mellifera genome, we have inferred more than 200 neuropeptides and have confirmed the sequences of 100 peptides. This study lays the groundwork for future molecular studies of Apis neuropeptides with the identification of 36 genes, 33 of which were previously unreported.

In response to crowding, locusts develop characteristic black patterns that are well discernible in the gregarious phase at outbreaks. We report here a dark-color-inducing neuropeptide (dark-pigmentotropin) from the corpora cardiaca of two plague locusts, Schistocerca gregaria and Locusta migratoria . The chromatographic isolation of this neuropeptide was monitored by using a bioassay with an albino mutant of L. migratoria. The neurohormone, consisting of 11 amino acids, is identical to [His ⁷ ] corazonin, previously isolated from corpora cardiaca of another acridid without known function. The present results show that even in isolated (solitary) nymphs, [His ⁷ ] corazonin induces gregarious black patterns. Its primary structure shows some similarity with the vertebrate melanophore stimulating hormone.

Neuropeptides regulate most, if not all, biological processes in the animal kingdom, but only seven have been isolated and sequenced from Drosophila melanogaster. In analogy with the proteomics technology, where all proteins expressed in a cell or tissue are analyzed, the peptidomics approach aims at the simultaneous identification of the whole peptidome of a cell or tissue,i.e. all expressed peptides with their posttranslational modifications. Using nanoscale liquid chromatography combined with tandem mass spectrometry and data base mining, we analyzed the peptidome of the larval Drosophila central nervous system at the amino acid sequence level. We were able to provide biochemical evidence for the presence of 28 neuropeptides using an extract of only 50 larval Drosophila central nervous systems. Eighteen of these peptides are encoded in previously cloned or annotated precursor genes, although not all of them were predicted correctly. Eleven of these peptides were never purified before. Eight other peptides are entirely novel and are encoded in five different, not yet annotated genes. This neuropeptide expression profiling study also opens perspectives for other eukaryotic model systems, for which genome projects are completed or in progress.

Biologically active peptides are synthesized as larger inactive proprotein peptide precursors which are processed by the concerted action of a cascade of enzymes. Among the proprotein convertases, PC2 is widely expressed in neuro‐endocrine tissues and has been proposed to be the major convertase involved in the biosynthesis of neuropeptides. In this study, we have examined the role of the Caenorhabditis elegans orthologue PC2/EGL‐3 in the processing of proprotein peptide precursors. We recently isolated and identified 60 endogenous peptides in the nematode C. elegans by two‐dimensional nanoscale liquid chromatography – quadrupole time‐of‐flight tandem mass spectrometry. In the present study, we compare the peptide profile of different C. elegans strains, including PC2/EGL‐3 mutants. For this purpose, we used an offline approach in which HPLC fractions are analysed by a matrix‐assisted laser desorption ionisation – time of flight mass spectrometer. This differential peptidomic approach unambiguously provides evidence for the role of PC2/EGL‐3 in the processing of FMRFamide‐like peptide (FLP) precursors and neuropeptide‐like protein (NLP) precursors in nematodes.

It was long assumed that proteins are at least 100 amino acids (AAs) long. Moreover, the detection of short translation products (e.g. coded from small Open Reading Frames, sORFs) is very difficult as the short length makes it hard to distinguish true coding ORFs from ORFs occurring by chance. Nevertheless, over the past few years many such non-canonical genes (with ORFs < 100 AAs) have been discovered in different organisms like Arabidopsis thaliana, Saccharomyces cerevisiae, and Drosophila melanogaster. Thanks to advances in sequencing, bioinformatics and computing power, it is now possible to scan the genome in unprecedented scrutiny, for example in a search of this type of small ORFs.

Extracellular vesicles (EVs) have a great potential in clinical applications. However, their isolation from different bodily fluids and their characterisation are currently not optimal or standardised. Here, we report the results of examining the performance of ultrafiltration combined with size exclusion chromatography (UF‐SEC) to isolate EVs from urine. The results reveal that UF‐SEC is an efficient method and provides high purity. Furthermore, we introduce asymmetrical‐flow field‐flow fractionation coupled with a UV detector and multi‐angle light‐scattering detector (AF4/UV‐MALS) as a characterisation method and compare it with current methods. We demonstrate that AF4/UV‐MALS is a straightforward and reproducible method for determining size, amount and purity of isolated urinary EVs.