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Statistics over-represented peptides HLA class I

Statistics over-represented peptides HLA class II

Supplementary Tables 1-5, 7, 9-12 containing: Suppl. Table 1: Sample characteristics; Suppl. Table 2: Patient characteristics; Suppl. Table 3: Control peptides Suppl. Table 4: Peptide-specific properties Suppl. Table 5: Over-represented Peptides HLA class I; Suppl. Table 7: Over-represented Peptides HLA class II; Suppl. Table 9: STRING results Suppl. Table 9: Protein-protein interactions (STRING) Suppl. Table 10: Over-represented pathways (STRING) Suppl. Table 11: Vaccine peptide selection Suppl. Table 12: Candidate vaccine peptides

Immune cell infiltrates have proven highly relevant for colorectal carcinoma prognosis, making colorectal cancer a promising candidate for immunotherapy. Because tumors interact with the immune system via HLA-presented peptide ligands, exact knowledge of the peptidome constitution is fundamental for understanding this relationship. Here, we comprehensively describe the naturally presented HLA ligandome of colorectal carcinoma and corresponding nonmalignant colon (NMC) tissue. Mass spectrometry identified 35,367 and 28,132 HLA class I ligands on colorectal carcinoma and NMC, attributable to 7,684 and 6,312 distinct source proteins, respectively. Cancer-exclusive peptides were assessed on source protein level using the Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein analysis through evolutionary relationships (PANTHER), revealing pathognomonic colorectal carcinoma–associated pathways, including Wnt, TGFβ, PI3K, p53, and RTK-RAS. Relative quantitation of peptide presentation on paired colorectal carcinoma and NMC tissue further identified source proteins from cancer- and infection-associated pathways to be overrepresented merely within the colorectal carcinoma ligandome. From the pool of tumor-exclusive peptides, a selected HLA-ligand subset was assessed for immunogenicity, with the majority exhibiting an existing T-cell repertoire. Overall, these data show that the HLA ligandome reflects cancer-associated pathways implicated in colorectal carcinoma oncogenesis, suggesting that alterations in tumor cell metabolism could result in cancer-specific, albeit not mutation-derived, tumor antigens. Hence, a defined pool of unique tumor peptides, attributable to complex cellular alterations that are exclusive to malignant cells, might comprise promising candidates for immunotherapeutic applications.Significance: Cancer-associated pathways are reflected in the antigenic landscape of colorectal cancer, suggesting that tumor-specific antigens do not necessarily have to be mutation-derived but may also originate from other alterations in cancer cells. Cancer Res; 78(16); 4627–41. ©2018 AACR.

Complete supplementary figures containing: Suppl. Fig. 1: HLA-coverage (Caucasian); Suppl. Fig. 2: Maximum attainable quantities of source proteins; Suppl. Fig. 3: Comparsion with complete benign dataset; Suppl. Fig. 4: Legend PANTHER analysis; Suppl. Fig. 5: Legend KEGG analysis; Suppl. Fig. 6: Representation analysis HLA class II

The opportunistic pathogen Staphylococcus aureus has become a major threat for human health and well-being by developing resistance to antibiotics and by fast evolution into new lineages that rapidly spread within the healthy human population. This calls for development of active or passive immunization strategies to prevent or treat acute phase infections. Since no such anti-staphylococcal immunization approaches are available for clinical implementation, the present studies were aimed at identifying new leads for their development. For this purpose, we profiled the cell-surface-exposed staphylococcal proteome under infection-mimicking conditions by combining two approaches for "bacterial shaving" with immobilized or soluble trypsin and subsequent mass spectrometry analysis of liberated peptides. In parallel, non-covalently cell-wall-bound proteins extracted with potassium thiocyanate and the exoproteome fraction were analyzed by gel-free proteomics. All data are available through ProteomeXchange accession PXD000156. To pinpoint immunodominant bacterial-surface-exposed epitopes, we screened selected cell-wall-attached proteins of S. aureus for binding of immunoglobulin G from patients who have been challenged by different types of S. aureus due to chronic wound colonization. The combined results of these analyses highlight particular cell-surface-exposed S. aureus proteins with highly immunogenic exposed epitopes as potential targets for development of protective anti-staphylococcal immunization strategies.

Seasonal influenza outbreaks represent a large burden for the health care system as well as the economy. While the role of the microbiome has been elucidated in the context of various diseases, the impact of respiratory viral infections on the human microbiome is largely unknown. In this study, swine was used as an animal model to characterize the temporal dynamics of the respiratory and gastrointestinal microbiome in response to an influenza A virus (IAV) infection. A multi-omics approach was applied on fecal samples to identify alterations in microbiome composition and function during IAV infection. We observed significantly altered microbial richness and diversity in the gastrointestinal microbiome after IAV infection. In particular, increased abundances of Prevotellaceae were detected, while Clostridiaceae and Lachnospiraceae decreased. Moreover, our metaproteomics data indicated that the functional composition of the microbiome was heavily affected by the influenza infection. For instance, we identified decreased amounts of flagellin, correlating with reduced abundances of Lachnospiraceae and Clostridiaceae, possibly indicating involvement of a direct immune response toward flagellated Clostridia during IAV infection. Furthermore, enzymes involved in short-chain fatty acid (SCFA) synthesis were identified in higher abundances, while metabolome analyses revealed rather stable concentrations of SCFAs. In addition, 16S rRNA gene sequencing was used to characterize effects on the composition and natural development of the upper respiratory tract microbiome. Our results showed that IAV infection resulted in significant changes in the abundance of Moraxellaceae and Pasteurellaceae in the upper respiratory tract. Surprisingly, temporal development of the respiratory microbiome structure was not affected. IMPORTANCE Here, we used swine as a biomedical model to elucidate the impact of influenza A H1N1 infection on structure and function of the respiratory and gastrointestinal tract microbiome by employing a multi-omics analytical approach. To our knowledge, this is the first study to investigate the temporal development of the porcine microbiome and to provide insights into the functional capacity of the gastrointestinal microbiome during influenza A virus infection.

The promising potential of cold atmospheric plasma (CAP) treatment as a new therapeutic option in the field of medicine, particularly in Otorhinolaryngology and Respiratory medicine, demands primarily the assessment of potential risks and the prevention of any direct and future cell damages. Consequently, the application of a special intensity of CAP that is well tolerated by cells and tissues is of particular interest. Although improvement of wound healing by CAP treatment has been described, the underlying mechanisms and the molecular influences on human tissues are so far only partially characterized. In this study, human S9 bronchial epithelial cells were treated with cold plasma of atmospheric pressure plasma jet that was previously proven to accelerate the wound healing in a clinically relevant extent. We studied the detailed cellular adaptation reactions for a specified plasma intensity by time-resolved comparative proteome analyses of plasma treated vs. nontreated cells to elucidate the mechanisms of the observed improved wound healing and to define potential biomarkers and networks for the evaluation of plasma effects on human epithelial cells. K-means cluster analysis and time-related analysis of fold-change factors indicated concordantly clear differences between the short-term (up to 1 h) and long-term (24-72 h) adaptation reactions. Thus, the induction of Nrf2-mediated oxidative and endoplasmic reticulum stress response, PPAR-alpha/RXR activation as well as production of peroxisomes, and prevention of apoptosis already during the first hour after CAP treatment are important cell strategies to overcome oxidative stress and to protect and maintain cell integrity and especially microtubule dynamics. After resolving of stress, when stress adaptation was accomplished, the cells seem to start again with proliferation and cellular assembly and organization. The observed strategies and identification of marker proteins might explain the accelerated wound healing induced by CAP, and these indicators might be subsequently used for risk assessment and quality management of application of nonthermal plasma sources in clinical settings.

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic is a major health burden. Volatile garlic organosulfur compounds, such as the thiol-reactive allicin (diallyl thiosulfinate) exert strong antimicrobial activity against various respiratory pathogens. Here, we investigated the antiviral activity of allicin against SARS-CoV-2 in infected Vero E6 and Calu-3 lung cells. Calu-3 cells showed greater allicin tolerance due >4-fold increased GSH levels compared to Vero E6. However, biocompatible allicin doses efficiently inhibited viral replication in both cell lines. Proteome analyses of SARS-CoV-2 infected Calu-3 cells revealed a strong induction of the antiviral interferon-stimulated gene (ISG) signature (e.g. cGAS, Mx1, IFIT, IFIH, IFI16, IFI44, 2’5’OAS and ISG15), pathways of vesicular transport, tight junctions (KIF5A/B/C, OSBPL2, CLTC1, ARHGAP17) and ubiquitin modification (UBE2L3/5), as well as reprogramming of host metabolism, transcription and translation. Allicin abrogated the ISG host response and reverted the host cellular pathways to levels of uninfected Calu-3 cells, confirming the antiviral and immunomodulatory activity of allicin in the host proteome. Thus, biocompatible doses of allicin could be promising for protection of lung cells against SARS-CoV-2.

To be a successful pathogen, Staphylococcus aureus has to adapt its metabolism to the typically oxygen- and glucose-limited environment of the host. Under fermenting conditions and in the presence of glucose, S. aureus uses glycolysis to generate ATP via substrate-level phosphorylation and mainly lactic acid fermentation to maintain the redox balance by reoxidation of NADH equivalents. However, it is less clear how S. aureus proceeds under anoxic conditions and glucose limitation, likely representing the bona fide situation in the host. Using a combination of proteomic, transcriptional, and metabolomic analyses, we show that in the absence of an abundant glycolysis substrate, the available carbon source pyruvate is converted to acetyl coenzyme A (AcCoA) in a pyruvate formate-lyase (PflB)-dependent reaction to produce ATP and acetate. This process critically depends on derepression of the catabolite control protein A (CcpA), leading to upregulation of pflB transcription. Under these conditions, ethanol production is repressed to prevent wasteful consumption of AcCoA. In addition, our global and quantitative characterization of the metabolic switch prioritizing acetate over lactate fermentation when glucose is absent illustrates examples of carbon source-dependent control of colonization and pathogenicity factors. IMPORTANCE Under infection conditions, S. aureus needs to ensure survival when energy production via oxidative phosphorylation is not possible, e.g., either due to the lack of terminal electron acceptors or by the inactivation of components of the respiratory chain. Under these conditions, S. aureus can switch to mixed-acid fermentation to sustain ATP production by substrate level phosphorylation. The drop in the cellular NAD+/NADH ratio is sensed by the repressor Rex, resulting in derepression of fermentation genes. Here, we show that expression of fermentation pathways is further controlled by CcpA in response to the availability of glucose to ensure optimal resource utilization under growth-limiting conditions. We provide evidence for carbon source-dependent control of colonization and virulence factors. These findings add another level to the regulatory network controlling mixed-acid fermentation in S. aureus and provide additional evidence for the lifestyle-modulating effect of carbon sources available to S. aureus.

Lichens represent self-supporting symbioses, which occur in a wide range of terrestrial habitats and which contribute significantly to mineral cycling and energy flow at a global scale. Lichens usually grow much slower than higher plants. Nevertheless, lichens can contribute substantially to biomass production. This review focuses on the lichen symbiosis in general and especially on the model speciesLobaria pulmonariaL. Hoffm., which is a large foliose lichen that occurs worldwide on tree trunks in undisturbed forests with long ecological continuity. In comparison to many other lichens,L.pulmonariais less tolerant to desiccation and highly sensitive to air pollution. The name-giving mycobiont (belonging to the Ascomycota), provides a protective layer covering a layer of the green-algal photobiont (Dictyochloropsis reticulata) and interspersed cyanobacterial cell clusters (Nostocspec.). Recently performed metaproteome analyses confirm the partition of functions in lichen partnerships. The ample functional diversity of the mycobiont contrasts the predominant function of the photobiont in production (and secretion) of energy-rich carbohydrates, and the cyanobiont’s contribution by nitrogen fixation. In addition, high throughput and state-of-the-art metagenomics and community fingerprinting, metatranscriptomics, and MS-based metaproteomics identify the bacterial community present onL. pulmonariaas a surprisingly abundant and structurally integrated element of the lichen symbiosis. Comparative metaproteome analyses of lichens from different sampling sites suggest the presence of a relatively stable core microbiome and a sampling site-specific portion of the microbiome. Moreover, these studies indicate how the microbiota may contribute to the symbiotic system, to improve its health, growth and fitness.

The opportunistic pathogen

Immune cell infiltrates have proven highly relevant for colorectal carcinoma prognosis, making colorectal cancer a promising candidate for immunotherapy. Because tumors interact with the immune system via HLA-presented peptide ligands, exact knowledge of the peptidome constitution is fundamental for understanding this relationship. Here, we comprehensively describe the naturally presented HLA ligandome of colorectal carcinoma and corresponding nonmalignant colon (NMC) tissue. Mass spectrometry identified 35,367 and 28,132 HLA class I ligands on colorectal carcinoma and NMC, attributable to 7,684 and 6,312 distinct source proteins, respectively. Cancer-exclusive peptides were assessed on source protein level using the Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein analysis through evolutionary relationships (PANTHER), revealing pathognomonic colorectal carcinoma–associated pathways, including Wnt, TGFβ, PI3K, p53, and RTK-RAS. Relative quantitation of peptide presentation on paired colorectal carcinoma and NMC tissue further identified source proteins from cancer- and infection-associated pathways to be overrepresented merely within the colorectal carcinoma ligandome. From the pool of tumor-exclusive peptides, a selected HLA-ligand subset was assessed for immunogenicity, with the majority exhibiting an existing T-cell repertoire. Overall, these data show that the HLA ligandome reflects cancer-associated pathways implicated in colorectal carcinoma oncogenesis, suggesting that alterations in tumor cell metabolism could result in cancer-specific, albeit not mutation-derived, tumor antigens. Hence, a defined pool of unique tumor peptides, attributable to complex cellular alterations that are exclusive to malignant cells, might comprise promising candidates for immunotherapeutic applications. Significance: Cancer-associated pathways are reflected in the antigenic landscape of colorectal cancer, suggesting that tumor-specific antigens do not necessarily have to be mutation-derived but may also originate from other alterations in cancer cells. Cancer Res; 78(16); 4627–41. ©2018 AACR.

This study aimed to establish a robust and reliable metaproteomics protocol for an in-depth characterization of marine particle-associated (PA) bacteria. To this end, we compared six well-established protein extraction protocols together with different MS-sample preparation techniques using particles sampled during a North Sea spring algae bloom in 2009. In the final optimized workflow, proteins are extracted using a combination of SDS-containing lysis buffer and cell disruption by bead-beating, separated by SDS-PAGE, in-gel digested and analysed by LC-MS/MS, before MASCOT search against a metagenome-based database and data processing/visualization with the in-house-developed bioinformatics tools Prophane and Paver. As an application example, free-living (FL) and particulate communities sampled in April 2009 were analysed, resulting in an as yet unprecedented number of 9354 and 5034 identified protein groups for FL and PA bacteria, respectively. Our data suggest that FL and PA communities appeared similar in their taxonomic distribution, with notable exceptions: eukaryotic proteins and proteins assigned to Flavobacteriia, Cyanobacteria, and some proteobacterial genera were found more abundant on particles, whilst overall proteins belonging to Proteobacteria were more dominant in the FL fraction. Furthermore, our data points to functional differences including proteins involved in polysaccharide degradation, sugar- and phosphorus uptake, adhesion, motility, and stress response.

Staphylococcus aureus is a major human pathogen, which causes life-threatening systemic and chronic infections and rapidly acquires resistance to multiple antibiotics. Thus, new antimicrobial compounds are required to combat infections with drug resistant S. aureus isolates. The 2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphthoquinone lapachol was previously shown to exert antimicrobial effects. In this study, we investigated the antimicrobial mode of action of lapachol in S. aureus using RNAseq transcriptomics, redox biosensor measurements, S-bacillithiolation assays and phenotype analyses of mutants. In the RNA-seq transcriptome, lapachol caused an oxidative and quinone stress response as well as protein damage as revealed by induction of the PerR, HypR, QsrR, MhqR, CtsR and HrcA regulons. Lapachol treatment further resulted in up-regulation of the SigB and GraRS regulons, which is indicative for cell wall and general stress responses. The redox-cycling mode of action of lapachol was supported by an elevated bacillithiol (BSH) redox potential (EBSH), higher endogenous ROS levels, a faster H2O2 detoxification capacity and increased thiol-oxidation of GapDH and the HypR repressor in vivo. The ROS scavenger N-acetyl cysteine and microaerophilic growth conditions improved the survival of lapachol-treated S. aureus cells. Phenotype analyses revealed an involvement of the catalase KatA and the Brx/BSH/YpdA pathway in protection against lapachol-induced ROS-formation in S. aureus. However, no evidence for irreversible protein alkylation and aggregation was found in lapachol-treated S. aureus cells. Thus, the antimicrobial mode of action of lapachol in S. aureus is mainly caused by ROS formation resulting in an oxidative stress response, an oxidative shift of the EBSH and increased protein thiol-oxidation. As ROS-generating compound, lapachol is an attractive alternative antimicrobial to combat multi-resistant S. aureus isolates. Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.

SummaryThis study aimed to establish a robust, reproducible and reliable metaproteomic pipeline for an in-depth characterization of marine particle-associated (PA) bacteria. To this end, we compared six well-established protein extraction protocols together with different MS-sample preparation techniques using particles sampled during a North Sea spring algae bloom in 2009. In this optimized workflow, proteins are extracted using a combination of SDS-containing lysis buffer and cell disruption by bead-beating, separated by SDS-PAGE, in-gel digested and analysed by LC-MS/MS, before MASCOT search against a metagenome-based database and data processing/visualization with the in-house-developed bioinformatics tools Prophane and Paver.As proof of principle, free-living (FL) and particulate communities sampled in April 2009 were analysed, resulting in an as yet unprecedented number of 9,354 and 5,034 identified protein groups for FL and PA bacteria, respectively. Our data revealed that FL and PA communities appeared similar in their taxonomic distribution, with notable exceptions: eukaryotic proteins and proteins assigned to Flavobacteriia, Cyanobacteria, and some proteobacterial genera were found more abundant on particles, whilst overall proteins belonging to Proteobacteria were more dominant in the FL fraction. In contrast, significant functional differences including proteins involved in polysaccharide degradation, sugar- and phosphorus uptake, adhesion, motility, and stress response were detected.Originality-Significance StatementMarine particles consist of organic particulate matter (e.g. phyto- or zooplankton) and particle-associated (PA) microbial communities, which are often embedded in a sugary matrix. A significant fraction of the decaying algal biomass in marine ecosystems is expected to be mineralized by PA heterotrophic communities, which are thus greatly contributing to large-scale carbon fluxes. Whilst numerous studies have investigated the succession of planktonic marine bacteria along phytoplankton blooms, the community structure and functionality of PA bacterial communities remained largely unexplored and knowledge on specific contributions of these microorganisms to carbon cycling is still surprisingly limited. This has been mostly been due to technical problems, i.e. to the difficulty to retrieve genomic DNA and proteins from these polysaccharide-rich entities, their enormous complexity and the high abundance of eukaryotic microorganisms.Our study presents an innovative, robust, reproducible, and reliable metaproteomics pipeline for marine particles, which will help to address and fill the above-described knowledge gap. Employing the here established workflow enabled us to identify more than 5,000 PA proteins, which is, at least to our knowledge, the largest number of protein groups ever assigned to marine particles. Notably, the novel pipeline has been validated by a first, comparative metaproteome analysis of free-living and PA bacterial communities indicating a significant functional shift enabling surface-associated bacteria to adapt to particle-specific living conditions. In conclusion, our novel metaproteomics pipeline presents a solid and promising methodological groundwork for future culture-independent analyses of seasonal taxonomic and functional successions of PA microbial communities in aquatic habitats.

The translation inhibitor linezolid is an antibiotic of last resort against Gram-positive pathogens including methicillin resistant strains of the nosocomial pathogen Staphylococcus aureus. Linezolid is reported to inhibit production of extracellular virulence factors, but the molecular cause is unknown. To elucidate the physiological response of S. aureus to linezolid in general and the inhibition of virulence factor synthesis in particular a holistic study was performed.Linezolid was added to exponentially growing S. aureus cells and the linezolid stress response was analyzed with transcriptomics and quantitative proteomics methods. In addition, scanning and transmission electron microscopy experiments as well as fluorescence microscopy analyses of the cellular DNA and membrane were performed.As previously observed in studies on other translation inhibitors, S. aureus adapts its protein biosynthesis machinery to the reduced translation efficiency. For example the synthesis of ribosomal proteins was induced. Also unexpected results like a decline in the amount of extracellular and membrane proteins were obtained. In addition, cell shape and size changed after linezolid stress and cell division was diminished. Finally, the chromosome was condensed after linezolid stress and lost contact to the membrane. These morphological changes cannot be explained by established theories. A new hypothesis is discussed, which suggests that the reduced amount of membrane and extracellular proteins and observed defects in cell division are due to the disintegration of transertion complexes by linezolid. (C) 2016 Elsevier GmbH. All rights reserved.

Aims: Quinone compounds are electron carriers and have antimicrobial and toxic properties due to their mode of actions as electrophiles and oxidants. However, the regulatory mechanism of quinone resistance is less well understood in the pathogen Staphylococcus aureus. Results: Methylhydroquinone (MHQ) caused a thiol-specific oxidative and electrophile stress response in the S. aureus transcriptome as revealed by the induction of the PerR, QsrR, CstR, CtsR, and HrcA regulons. The SACOL2531-29 operon was most strongly upregulated by MHQ and was renamed as mhqRED operon based on its homology to the Bacillus subtilis locus. Here, we characterized the MarR-type regulator MhqR (SACOL2531) as quinone-sensing repressor of the mhqRED operon, which confers quinone and antimicrobial resistance in S. aureus. The mhqRED operon responds specifically to MHQ and less pronounced to pyocyanin and ciprofloxacin, but not to reactive oxygen species (ROS), hypochlorous acid, or aldehydes. The MhqR repressor binds specifically to a 9–9 bp inverted repeat (MhqR operator) upstream of the mhqRED operon and is inactivated by MHQ in vitro, which does not involve a thiol-based mechanism. In phenotypic assays, the mhqR deletion mutant was resistant to MHQ and quinone-like antimicrobial compounds, including pyocyanin, ciprofloxacin, norfloxacin, and rifampicin. In addition, the mhqR mutant was sensitive to sublethal ROS and 24 h post-macrophage infections but acquired an improved survival under lethal ROS stress and after long-term infections. Innovation: Our results provide a link between quinone and antimicrobial resistance via the MhqR regulon of S. aureus. Conclusion: The MhqR regulon was identified as a novel resistance mechanism towards quinone-like antimicrobials and contributes to virulence of S. aureus under long-term infections.

The prevalence of methicillin-resitant Staphylococcus aureus (MRSA) in hospitals and the community poses an increasing health burden, which requires the discovery of alternative antimicrobials. Allicin (diallyl thiosulfinate) from garlic exhibits broad-spectrum antimicrobial activity against many multidrug resistant bacteria. The thiol-reactive mode of action of allicin involves its S-thioallylations of low molecular weight (LMW) thiols and protein thiols. To investigate the mode of action and stress response caused by allicin in S. aureus, we analyzed the transcriptome signature, the targets for S-thioallylation in the proteome and the changes in the bacillithiol (BSH) redox potential (EBSH) under allicin stress. Allicin caused a strong thiol-specific oxidative and sulfur stress response and protein damage as revealed by the induction of the PerR, HypR, QsrR, MhqR, CstR, CtsR, HrcA and CymR regulons in the RNA-seq transcriptome. Allicin also interfered with metal and cell wall homeostasis and caused induction of the Zur, CsoR and GraRS regulons. Brx-roGFP2 biosensor measurements revealed a strongly increased EBSH under allicin stress. In the proteome, 57 proteins were identified with S-thioallylations under allicin treatment, including translation factors (EF-Tu, EF-Ts), metabolic and redox enzymes (AldA, GuaB, Tpx, KatA, BrxA, MsrB) as well as redox-sensitive MarR/SarA-family regulators (MgrA, SarA, SarH1, SarS). Phenotype and biochemical analyses revealed that BSH and the HypR-controlled disulfide reductase MerA are involved in allicin detoxification in S. aureus. The reversal of protein S-thioallylation was catalyzed by the Brx/BSH/YpdA pathway. Finally, the BSSB reductase YpdA was shown to use S-allylmercaptobacillithiol (BSSA) as substrate to regenerate BSH in S. aureus. In conclusion, allicin results in an oxidative shift of EBSH and protein S-thioallylation, which can be reversed by YpdA and the Brx/BSH/YpdA electron pathways in S. aureus to regenerate thiol homeostasis. Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.

A single clove of edible garlic (Allium sativum L.) of about 10 g produces up to 5 mg of allicin (diallylthiosulfinate), a thiol-reactive sulfur-containing defence substance that gives injured garlic tissue its characteristic smell. Allicin induces apoptosis or necrosis in a dose-dependent manner but biocompatible doses influence cellular metabolism and signalling cascades. Oxidation of protein thiols and depletion of the glutathione pool are thought to be responsible for allicin's physiological effects. Here, we studied the effect of allicin on post-translational thiol-modification in human Jurkat T-cells using shotgun LC-MS/MS analyses. We identified 332 proteins that were modified by S-thioallylation in the Jurkat cell proteome which causes a mass shift of 72 Da on cysteines. Many S-thioallylated proteins are highly abundant proteins, including cytoskeletal proteins tubulin, actin, cofilin, filamin and plastin-2, the heat shock chaperones HSP90 and HSPA4, the glycolytic enzymes GAPDH, ALDOA, PKM as well the protein translation factor EEF2. Allicin disrupted the actin cytoskeleton in murine L929 fibroblasts. Allicin stimulated the immune response by causing Zn2+ release from proteins and increasing the Zn2+-dependent IL-1-triggered production of IL-2 in murine EL-4 T-cells. Furthermore, allicin caused inhibition of enolase activity, an enzyme considered a cancer therapy target. In conclusion, our study revealed the widespread extent of S-thioallylation in the human Jurkat cell proteome and showed effects of allicin exposure on essential cellular functions of selected targets, many of which are targets for cancer therapy., Graphical abstract fx1, Highlights • Allicin from garlic caused S-thioallylation of 332 proteins in the human Jurkat cell proteome. • Main S-thioallylated proteins are cytoskeletal proteins, chaperones, glycolytic enzymes, translation factors. • Selected S-thioallylated proteins were shown to be inhibited by allicin. • Allicin disrupted the cytoskeleton, decreased enolase activity and enhanced Zn2+ release. • Mode of action of allicin in mammalian cells could explain its cytostatic effect in cancer cells.

The proteogenomes and secretomes of dominant human and zoonotic S. aureus lineages CC8, CC22 and CC398 were compared revealing genomic and regulatory differences in the secretion of 869 proteins. In the core secretome, 101 secreted or cell surface anchored virulence factors contribute with 82.4% to total secretome abundance. CC398 isolates showed higher secretion of α- and ß-hemolysins and lower secretion of surface proteins resulting in strong hemolysis and decreased biofilm formation because of lower SigB activity compared to human-specific CC8 and CC22., Graphical Abstract Highlights Proteogenomics and secretome comparison of human and zoonotic Staphylococcus aureus lineages.869 secreted proteins identified in eight S. aureus isolates of CC8, CC22 and CC398.CC398 lower secretion of surface proteins and higher secretion of hemolysins and exoenzymes.Regulatory differences in the secretomes could be linked to lower SigB activity in CC398., The spread of methicillin-resistant Staphylococcus aureus (MRSA) in the community, hospitals and in livestock is mediated by highly diverse virulence factors that include secreted toxins, superantigens, enzymes and surface-associated adhesins allowing host adaptation and colonization. Here, we combined proteogenomics, secretome and phenotype analyses to compare the secreted virulence factors in selected S. aureus isolates of the dominant human- and livestock-associated genetic lineages CC8, CC22, and CC398. The proteogenomic comparison revealed 2181 core genes and 1306 accessory genes in 18 S. aureus isolates reflecting the high genome diversity. Using secretome analysis, we identified 869 secreted proteins with 538 commons in eight isolates of CC8, CC22, and CC398. These include 64 predicted extracellular and 37 cell surface proteins that account for 82.4% of total secretome abundance. Among the top 10 most abundantly secreted virulence factors are the major autolysins (Atl, IsaA, Sle1, SAUPAN006375000), lipases and lipoteichoic acid hydrolases (Lip, Geh, LtaS), cytolytic toxins (Hla, Hlb, PSMβ1) and proteases (SspB). The CC398 isolates showed lower secretion of cell wall proteins, but higher secretion of α- and β-hemolysins (Hla, Hlb) which correlated with an increased Agr activity and strong hemolysis. CC398 strains were further characterized by lower biofilm formation and staphyloxanthin levels because of decreased SigB activity. Overall, comparative secretome analyses revealed CC8- or CC22-specific enterotoxin and Spl protease secretion as well as Agr- and SigB-controlled differences in exotoxin and surface protein secretion between human-specific and zoonotic lineages of S. aureus.

Aims: Bacillithiol (BSH) is the major low-molecular-weight thiol of the human pathogen Staphylococcus aureus. In this study, we used OxICAT and Voronoi redox treemaps to quantify hypochlorite-sensitive protein thiols in S. aureus USA300 and analyzed the role of BSH in protein S-bacillithiolation. Results: The OxICAT analyses enabled the quantification of 228 Cys residues in the redox proteome of S. aureus USA300. Hypochlorite stress resulted in >10% increased oxidation of 58 Cys residues (25.4%) in the thiol redox proteome. Among the highly oxidized sodium hypochlorite (NaOCl)-sensitive proteins are five S-bacillithiolated proteins (Gap, AldA, GuaB, RpmJ, and PpaC). The glyceraldehyde-3-phosphate (G3P) dehydrogenase Gap represents the most abundant S-bacillithiolated protein contributing 4% to the total Cys proteome. The active site Cys151 of Gap was very sensitive to overoxidation and irreversible inactivation by hydrogen peroxide (H2O2) or NaOCl in vitro. Treatment with H2O2 or NaOCl in the presence of BSH resulted in reversible Gap inactivation due to S-bacillithiolation, which could be regenerated by the bacilliredoxin Brx (SAUSA300_1321) in vitro. Molecular docking was used to model the S-bacillithiolated Gap active site, suggesting that formation of the BSH mixed disulfide does not require major structural changes. Conclusion and Innovation: Using OxICAT analyses, we identified 58 novel NaOCl-sensitive proteins in the pathogen S. aureus that could play protective roles against the host immune defense and include the glycolytic Gap as major target for S-bacillithiolation. S-bacillithiolation of Gap did not require structural changes, but efficiently functions in redox regulation and protection of the active site against irreversible overoxidation in S. aureus. Antioxid. Redox Signal. 28, 410–430.

Major differences in the transcriptional program underlying the phenotypic switch between exponential and post-exponential growth of Legionella pneumophila were formerly described characterizing important alterations in infection capacity. Additionally, a third state is known where the bacteria transform in a viable but nonculturable state under stress, such as starvation. We here describe phase-related proteomic changes in exponential phase (E), postexponential phase (PE) bacteria, and unculturable microcosms (UNC) containing viable but nonculturable state cells, and identify phase-specific proteins. We present data on different bacterial subproteomes of E and PE, such as soluble whole cell proteins, outer membrane-associated proteins, and extracellular proteins. In total, 1368 different proteins were identified, 922 were quantified and 397 showed differential abundance in E/PE. The quantified subproteomes of soluble whole cell proteins, outer membrane-associated proteins, and extracellular proteins; 841, 55, and 77 proteins, respectively, were visualized in Voronoi treemaps. 95 proteins were quantified exclusively in E, such as cell division proteins MreC, FtsN, FtsA, and ZipA; 33 exclusively in PE, such as motility-related proteins of flagellum biogenesis FlgE, FlgK, and FliA; and 9 exclusively in unculturable microcosms soluble whole cell proteins, such as hypothetical, as well as transport/binding-, and metabolism-related proteins. A high frequency of differentially abundant or phase-exclusive proteins was observed among the 91 quantified effectors of the major virulence-associated protein secretion system Dot/Icm (> 60%). 24 were E-exclusive, such as LepA/B, YlfA, MavG, Lpg2271, and 13 were PE-exclusive, such as RalF, VipD, Lem10. The growth phase-related specific abundance of a subset of Dot/Icm virulence effectors was confirmed by means of Western blotting. We therefore conclude that many effectors are predominantly abundant at either E or PE which suggests their phase specific function. The distinct temporal or spatial presence of such proteins might have important implications for functional assignments in the future or for use as life-stage specific markers for pathogen analysis.

Long-term catheterization inevitably leads to a catheter-associated bacteriuria caused by multispecies bacterial biofilms growing on and in the catheters. The overall goal of the presented study was (1) to unravel bacterial community structure and function of such a uropathogenic biofilm and (2) to elucidate the interplay between bacterial virulence and the human immune system within the urine. To this end, a metaproteomics approach combined with in vitro proteomics analyses was employed to investigate both, the pro- and eukaryotic protein inventory. Our proteome analyses demonstrated that the biofilm of the investigated catheter is dominated by three bacterial species, that is, Pseudomonas aeruginosa, Morganella morganii, and Bacteroides sp., and identified iron limitation as one of the major challenges in the bladder environment. In vitro proteome analysis of P. aeruginosa and M. morganii isolated from the biofilm revealed that these opportunistic pathogens are able to overcome iron restriction via the production of siderophores and high expression of corresponding receptors. Notably, a comparison of in vivo and in vitro protein profiles of P. aeruginosa and M. morganii also indicated that the bacteria employ different strategies to adapt to the urinary tract. Although P. aeruginosa seems to express secreted and surface-exposed proteases to escape the human innate immune system and metabolizes amino acids, M. morganii is able to take up sugars and to degrade urea. Most interestingly, a comparison of urine protein profiles of three long-term catheterized patients and three healthy control persons demonstrated the elevated level of proteins associated with neutrophils, macrophages, and the complement system in the patient's urine, which might point to a specific activation of the innate immune system in response to biofilm-associated urinary tract infections. We thus hypothesize that the often asymptomatic nature of catheter-associated urinary tract infections might be based on a fine-tuned balance between the expression of bacterial virulence factors and the human immune system.

BackgroundRuminant livestock is a major source of the potent greenhouse gas methane (CH4), produced by the complex rumen microbiome. Using an integrated approach, combining quantitative metatranscriptomics with gas- and volatile fatty acid (VFA) profiling, we gained fundamental insights into temporal dynamics of the cow rumen microbiome during feed degradation.ResultsThe microbiome composition was highly individual and remarkably stable within each cow, despite similar gas emission and VFA profiles between cows. Gene expression profiles revealed a fast microbial growth response to feeding, reflected by drastic increases in microbial biomass, CH4emissions and VFA concentrations. Microbiome individuality was accompanied by high inter- and intra-domain functional redundancy among pro- and eukaryotic microbiome members in the key steps of anaerobic feed degradation. Methyl-reducing but not CO2-reducing methanogens were correlated with increased CH4emissions during plant biomass degradation.ConclusionsThe major response of the rumen microbiome to feed intake was a general growth of the whole community. The high functional redundancy of the cow-individual microbiomes was possibly linked to the robust performance of the anaerobic degradation process. Furthermore, the strong response of methylotrophic methanogens is suggesting that they might play a more important role in ruminant CH4emissions than previously assumed, making them potential targets for CH4mitigation strategies.