We constructed a reference two-dimensional protein map for horse (Equus caballus) serum. The serum proteins were separated by two-dimensional electrophoresis (2-DE); 29 different gene products were identified. Proteins represented by 25 spots/spot groups were identified by tandem nanoelectrospray mass spectrometry (MS), four by matrix-assisted laser desorption ionization time-of-flight (TOF) MS and one was sequenced by TOF-TOF technology. The identities of four proteins were deduced by similarity to the human plasma protein database. In selected cases, i.e. the immunoglobulins, immunoblotting with specific antibodies provided additional information about the respective proteins. Albumin was detected as the full-length protein and as fragments of various sizes. Spots representing products of different mass and charge were also detected for alpha1-antitrypsin, haptoglobin and transthyretin. Thus, despite the fact that the Equus caballus genome is incompletely characterized, we were able to identify almost all moderate to high abundance proteins stained in the serum 2-DE pattern.

Summary: The uniqueness of a measured molecular mass or peptide sequence plays a very important role in the fields of protein identification and peptide/protein-biomarker investigation. We present a publicly available web application that offers information concerning the uniqueness of one or more molecular masses and one or more peptide sequences in the human proteome. When a sequence is found to be unique in humans, the application is able to search across all species querying whether this sequence is unique, not only in humans but also in other species found in the Swiss-Prot Database. The application is also able to search for unique protein fragments derived computationally from enzymatic digestion driven by certain enzymes. Furthermore, the application can list all the unique masses and peptides of a given protein. Through this application, researchers are able to find unique tags, either on a molecular mass level or on a sequence level. These unique tags are remarkably important in research related to protein identification or biomarker discovery and measurements. Availability: UniMaP web-application is available at http://bioserver-1.bioacademy.gr/Bioserver/UniMaP/ Contact:  gspyrou@bioacademy.gr Supplementary information:  Supplementary data are available at Bioinformatics online.

Objectives Crohn’s disease (CD) and ulcerative colitis (UC), known collectively as inflammatory bowel disease (IBD), are chronic immuno-inflammatory pathologies of unknown etiology. Despite the frequent utilization of biomarkers in medical practice, there is a relative lack of information regarding validated paediatric biomarkers for IBD. Further, biomarkers proved to be efficacious in adults are frequently extrapolated to the paediatric clinical setting without considering that the pathogenesis of many diseases is distinctly different in children. In the current study, proteomics technology was employed in order to monitor differences in protein expression among adult and children CD patients, in order to identify a panel of candidate protein biomarkers that might be used to improve prognostic-diagnostic accuracy and to advance paediatric medical care. Methods Male and female serum samples from 12 adults and 12 children with active CD were subjected to two-dimensional gel electrophoresis. Following the relative quantitation of protein spots exhibiting a differential expression between the two groups by densitometry, the spots were further characterized by MALDI-TOF-MS. Results were confirmed by Western blot analysis. Results Clusterin (CLUS) was found to be significantly over-expressed in adults with CD, whereas ceruloplasmin (CERU) and apolipoprotein B-100 (APOB) were found to be significantly over-expressed in children indicating that the expression of these proteins might be implicated in the onset or progression of CD in these two sub-groups of patients. Conclusions Interestingly, we found a differential expression of several proteins in adults versus paediatric CD patients. Undoubtedly, future experiments using a larger cohort of CD patients are needed to evaluate the relevance of our preliminary findings.