Bacteria
Proteomic Analysis of Salmonella-modified Membranes Reveals Adaptations to Macrophage HostsThe proteome of Salmonella-modified membranes has been extracted using an affinity-based proteome approach. The data highlight communalities between the compartment in epithelial and phagocytic cells, but also provide evidence for cell-specific adaptations in Salmonella pathogen-containing compartments. These observations provide novel insights into the mechanisms of host-dependent differences in the pathophysiology of Salmonella infections.
Discovery of Species-unique Peptide Biomarkers of Bacterial Pathogens by Tandem Mass Spectrometry-based ProteotypingPeptide biomarker candidates for the respiratory tract pathogens Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus are presented. First, bacterial cultures representing the genetic variability in each of the four species, were analyzed. The peptide biomarker candidates were then experimentally verified to be present in a clinical situation by analyzing true positive clinical samples. The most promising peptide biomarkers were used in a targeted MS mode, demonstrating their use for future clinical implementation.
Citrullinome of Porphyromonas gingivalis Outer Membrane Vesicles: Confident Identification of Citrullinated PeptidesThe citrullinome of P. gingivalis outer membrane vesicles (OMV) has been explored by a novel two-dimensional separation system combined with high resolution mass spectrometry and in-house build software. Analysis of OMVs from wild-type and two PPAD mutants resulted in confident discrimination based on citrullinated peptides. In the wild-type citrullinome 78 proteins were identified having a total of 161 validated citrullination sites. A single citrullination was identified in the C351A mutant and none in the ΔPPAD mutant.
Sample Preparation by Easy Extraction and Digestion (SPEED) - A Universal, Rapid, and Detergent-free Protocol for Proteomics Based on Acid ExtractionSample Preparation by Easy Extraction and Digestion (SPEED) is a universal method for peptide generation from various sources. Because of its detergent-free chemistry, SPEED offers some inherent benefits for bottom-up proteomics sample preparation, including improved quantitative reproducibility, simple applicability and enhanced proteome coverage for lysis-resistant sample types as well as very rapid sample processing. SPEED has high automatization potential and can contribute to simplify and standardize sample preparation and thus enhance reproducibility in proteomics.
Critical Role of a Sheath Phosphorylation Site On the Assembly and Function of an Atypical Type VI Secretion SystemKCl stimulation triggers assembly of the Francisella T6SS in culture. Differential whole cell proteomics reveals that the amounts of the T6SS proteins remain unchanged upon KCl stimulation. A phosphoproteomic analysis identifies a phosphorylation on the T6SS sheath, at site Y139 of IglB. Our data demonstrate that site Y139 of IglB plays a critical role in T6SS biogenesis, providing novel mechanistic insight into the role of sheath phosphorylation in T6SS biogenesis.