Which are less readily detected by conventional mass spectrometry approaches, and to keep the database to a reasonable size. Finally, we used the NCBI reference sequence database as a source for RNA transcripts. This non-redundant and well-annotated database is fairly conservative, and thus is a quality source for identifying candidate AltORFs, but it would be interesting to compare with other databases to verify if different mRNA isoforms could also serve as template for the expression of corresponding alternative proteins. Nevertheless, the location of AltORfs is comparable with the distribution obtained in a peptidomic study of small ORFs encoded polypeptides, with the exception of AltORFs located in 59UTRs. For these AltORFs, the apparent discrepancy probably results from our prediction of AltORFs initiating at AUG sites only. In conclusion, we have provided compelling evidence that alternative proteins significantly contribute to the human proteome by identifying 1259 new proteins and many more will likely be detected in further MS experiments. A comprehensive knowledge of the proteome is of crucial interest to unravel the cellular mechanisms underlying KRX-0401 supply health and disease. We believe that proteomics approaches supported by ribosome profiling will further benefit the establishment of an exhaustive catalog of proteins to fulfill this goal in the future. Higher organisms are continuously exposed to a great variety of pathogens such as viruses, mycoplasma, bacteria, and fungi. To fight these microbes they have developed several defense strategies, including the production of antimicrobial peptides. AMPs are effective weapons against a wide range of pathogens and are distributed throughout the animal and plant kingdom, suggesting that they are critical for the successful evolution of complex multicellular organisms. Despite their high sequence diversity, AMPs share fundamental structural properties such as short size, positive net charge, hydrophobic nature and clustering of cationic and hydrophobic amino acids within distinct domains of the molecule. Upon contact with pathogen membranes AMPs tend to adopt amphiphilic structures. Because of their cationic and hydrophobic features, antimicrobial peptides interact primarily with negatively charged biomembranes. Many bacterial membranes contain negatively charged components like hydroxylated phospholipids, lipopolysaccharides and teichonic acids and are therefore major targets for AMPs. The hydrophobic regions of the AMPs support incorporation of the peptides into the membranes, leading to pore formation and permeabilization. Several different models have been proposed for peptide insertion, of which the barrel-stave model, the carpet model, and the toroidal-pore model are the most popular ones. In plant protection, bacterial infections are hard to overcome, considering that plant disease control is mainly based on the application of chemical pesticides, which are under strong restrictions and regulatory requirements. However, about 14% of the total loss of all crops produced worldwide are caused by infectious diseases, resulting in a total annual loss of about 220 $ billion per year �C not including the 6�C12% losses of crop after harvest. Furthermore, microbial organisms often produce toxic compounds, which make food products uneatable or even dangerous for humans and animals. Therefore there is an urgent need for new antimicrobial agents. AMPs have attracted the interest of researchers for many years. Especially their mode of action, namely targeting fundamental features of microbial cell membranes, is thought to reduce the risk of resistance development in microbial populations �C as it happened in the past to every new antibiotic within a few years of its utilization since this would Nutlin-3 require a reorganization of the bacterial membranes.