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Ethanolamine utilization contributes to proliferation of Salmonella enterica serovar Typhimurium in food and in nematodes. Appl Environ Microbiol 2010; 77:281-90. [PMID: 21037291 DOI: 10.1128/aem.01403-10] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Only three pathogenic bacterial species, Salmonella enterica, Clostridium perfringens, and Listeria monocytogenes, are able to utilize both ethanolamine and 1,2-propanediol as a sole carbon source. Degradation of these substrates, abundant in food and the gut, depends on cobalamin, which is synthesized de novo only under anaerobic conditions. Although the eut, pdu, and cob-cbi gene clusters comprise 40 kb, the conditions under which they confer a selection advantage on these food-borne pathogens remain largely unknown. Here we used the luciferase reporter system to determine the response of the Salmonella enterica serovar Typhimurium promoters P(eutS), P(pocR), P(pduF), and P(pduA) to a set of carbon sources, to egg yolk, to whole milk, and to milk protein or fat fractions. Depending on the supplements, specific inductions up to 3 orders of magnitude were observed for P(eutS) and P(pduA), which drive the expression of most eut and pdu genes. To correlate these significant expression data with growth properties, nonpolar deletions of pocR, regulating the pdu and cob-cbi genes, and of eutR, involved in eut gene activation, were constructed in S. Typhimurium strain 14028. During exponential growth of the mutants 14028ΔpocR and 14028ΔeutR, 2- to 3-fold-reduced proliferation in milk and egg yolk was observed. Using the Caenorhabditis elegans infection model, we could also demonstrate that the proliferation of S. Typhimurium in the nematode is supported by an active ethanolamine degradation pathway. Taking these findings together, this study quantifies the differential expression of eut and pdu genes under distinct conditions and provides experimental evidence that the ethanolamine utilization pathway allows salmonellae to occupy specific metabolic niches within food environments and within their host organisms.
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Discovery of novel secreted virulence factors from Salmonella enterica serovar Typhimurium by proteomic analysis of culture supernatants. Infect Immun 2010; 79:33-43. [PMID: 20974834 DOI: 10.1128/iai.00771-10] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serovar Typhimurium is a leading cause of acute gastroenteritis throughout the world. This pathogen has two type III secretion systems (TTSS) encoded in Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2) that deliver virulence factors (effectors) to the host cell cytoplasm and are required for virulence. While many effectors have been identified and at least partially characterized, the full repertoire of effectors has not been catalogued. In this proteomic study, we identified effector proteins secreted into defined minimal medium designed to induce expression of the SPI-2 TTSS and its effectors. We compared the secretomes of the parent strain to those of strains missing essential (ssaK::cat) or regulatory (ΔssaL) components of the SPI-2 TTSS. We identified 20 known SPI-2 effectors. Excluding the translocon components SseBCD, all SPI-2 effectors were biased for identification in the ΔssaL mutant, substantiating the regulatory role of SsaL in TTS. To identify novel effector proteins, we coupled our secretome data with a machine learning algorithm (SIEVE, SVM-based identification and evaluation of virulence effectors) and selected 12 candidate proteins for further characterization. Using CyaA' reporter fusions, we identified six novel type III effectors and two additional proteins that were secreted into J774 macrophages independently of a TTSS. To assess their roles in virulence, we constructed nonpolar deletions and performed a competitive index analysis from intraperitoneally infected 129/SvJ mice. Six mutants were significantly attenuated for spleen colonization. Our results also suggest that non-type III secretion mechanisms are required for full Salmonella virulence.
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53
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Webb-Robertson BJM, Cannon WR, Oehmen CS, Shah AR, Gurumoorthi V, Lipton MS, Waters KM. A support vector machine model for the prediction of proteotypic peptides for accurate mass and time proteomics. Bioinformatics 2010; 26:1677-83. [PMID: 20568665 DOI: 10.1093/bioinformatics/btq251] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
MOTIVATION The standard approach to identifying peptides based on accurate mass and elution time (AMT) compares profiles obtained from a high resolution mass spectrometer to a database of peptides previously identified from tandem mass spectrometry (MS/MS) studies. It would be advantageous, with respect to both accuracy and cost, to only search for those peptides that are detectable by MS (proteotypic). RESULTS We present a support vector machine (SVM) model that uses a simple descriptor space based on 35 properties of amino acid content, charge, hydrophilicity and polarity for the quantitative prediction of proteotypic peptides. Using three independently derived AMT databases (Shewanella oneidensis, Salmonella typhimurium, Yersinia pestis) for training and validation within and across species, the SVM resulted in an average accuracy measure of approximately 0.83 with an SD of <0.038. Furthermore, we demonstrate that these results are achievable with a small set of 13 variables and can achieve high proteome coverage. AVAILABILITY http://omics.pnl.gov/software/STEPP.php CONTACT bj@pnl.gov SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Kim K, Yang E, Vu GP, Gong H, Su J, Liu F, Lu S. Mass spectrometry-based quantitative proteomic analysis of Salmonella enterica serovar Enteritidis protein expression upon exposure to hydrogen peroxide. BMC Microbiol 2010; 10:166. [PMID: 20529336 PMCID: PMC2897801 DOI: 10.1186/1471-2180-10-166] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Accepted: 06/08/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Salmonella enterica, a common food-borne bacterial pathogen, is believed to change its protein expression profile in the presence of different environmental stress such as that caused by the exposure to hydrogen peroxide (H2O2), which can be generated by phagocytes during infection and represents an important antibacterial mechanism of host cells. Among Salmonella proteins, the effectors of Salmonella pathogenicity island 1 and 2 (SPI-1 and SPI-2) are of particular interest since they are expressed during host infection in vivo and are important for invasion of epithelial cells and for replication in organs during systemic infection, respectively. However, the expression profiles of these proteins upon exposure to H2O2 or to host cells in vivo during the established phase of systemic infection have not been extensively studied. RESULTS Using stable isotope labeling coupled with mass spectrometry, we performed quantitative proteomic analysis of Salmonella enterica serovar Enteritidis and identified 76 proteins whose expression is modulated upon exposure to H2O2. SPI-1 effector SipC was expressed about 3-fold higher and SopB was expressed approximately 2-fold lower in the presence of H2O2, while no significant change in the expression of another SPI-1 protein SipA was observed. The relative abundance of SipA, SipC, and SopB was confirmed by Western analyses, validating the accuracy and reproducibility of our approach for quantitative analysis of protein expression. Furthermore, immuno-detection showed substantial expression of SipA and SipC but not SopB in the late phase of infection in macrophages and in the spleen of infected mice. CONCLUSIONS We have identified Salmonella proteins whose expression is modulated in the presence of H2O2. Our results also provide the first direct evidence that SipC is highly expressed in the spleen at late stage of salmonellosis in vivo. These results suggest a possible role of SipC and other regulated proteins in supporting survival and replication of Salmonella under oxidative stress and during its systemic infection in vivo.
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Affiliation(s)
- Kihoon Kim
- University of California, Berkeley, CA 94720, USA
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55
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Loss of the response regulator CtrA causes pleiotropic effects on gene expression but does not affect growth phase regulation in Rhodobacter capsulatus. J Bacteriol 2010; 192:2701-10. [PMID: 20363938 DOI: 10.1128/jb.00160-10] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The purple nonsulfur photosynthetic bacterium Rhodobacter capsulatus has been extensively studied for its metabolic versatility as well as for production of a gene transfer agent called RcGTA. Production of RcGTA is highest in the stationary phase of growth and requires the response regulator protein CtrA. The CtrA protein in Caulobacter crescentus has been thoroughly studied for its role as an essential, master regulator of the cell cycle. Although the CtrA protein in R. capsulatus shares a high degree of sequence similarity with the C. crescentus protein, it is nonessential and clearly plays a different role in this bacterium. We have used transcriptomic and proteomic analyses of wild-type and ctrA mutant cultures to identify the genes dysregulated by the loss of CtrA in R. capsulatus. We have also characterized gene expression differences between the logarithmic and stationary phases of growth. Loss of CtrA has pleiotropic effects, with dysregulation of expression of approximately 6% of genes in the R. capsulatus genome. This includes all flagellar motility genes and a number of other putative regulatory proteins but does not appear to include any genes involved in the cell cycle. Quantitative proteomic data supported 88% of the CtrA transcriptome results. Phylogenetic analysis of CtrA sequences supports the hypothesis of an ancestral ctrA gene within the alphaproteobacteria, with subsequent diversification of function in the major alphaproteobacterial lineages.
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56
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Adkins JN, Mottaz H, Metz TO, Ansong C, Manes NP, Smith RD, Heffron F. Performing comparative peptidomics analyses of Salmonella from different growth conditions. Methods Mol Biol 2010; 615:13-27. [PMID: 20013197 DOI: 10.1007/978-1-60761-535-4_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Host-pathogen interactions are complex competitions during which both the host and the pathogen adapt rapidly to each other in order for one or the other to survive. Salmonella enterica serovar Typhimurium is a pathogen with a broad host range that causes a typhoid fever-like disease in mice and severe food poisoning in humans. The murine typhoid fever is a systemic infection in which S. typhimurium evades part of the immune system by replicating inside macrophages and other cells. The transition from a foodborne contaminant to an intracellular pathogen must occur rapidly in multiple, ordered steps in order for S. typhimurium to thrive within its host environment. Using S. typhimurium isolated from rich culture conditions and from conditions that mimic the hostile intracellular environment of the host cell, a native low molecular weight protein fraction, or peptidome, was enriched from cell lysates by precipitation of intact proteins with organic solvents. The enriched peptidome was analyzed by both LC-MS/MS and LC-MS-based methods, although several other methods are possible. Pre-fractionation of peptides allowed identification of small proteins and protein degradation products that would normally be overlooked. Comparison of peptides present in lysates prepared from Salmonella grown under different conditions provided a unique insight into cellular degradation processes as well as identification of novel peptides encoded in the genome but not annotated. The overall approach is detailed here as applied to Salmonella and is adaptable to a broad range of biological systems.
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Affiliation(s)
- Joshua N Adkins
- Pacific Northwest National Laboratory, Fundamental and Computational Sciences Directorate, Richland, WA, USA
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57
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Kint G, Fierro C, Marchal K, Vanderleyden J, De Keersmaecker SCJ. Integration of ‘omics’ data: does it lead to new insights into host–microbe interactions? Future Microbiol 2010; 5:313-28. [DOI: 10.2217/fmb.10.1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The interaction between both beneficial and pathogenic microbes and their host has been the subject of many studies. Although the field of systems biology is rapidly evolving, the use of a systems biology approach by means of high-throughput techniques to study host–microbe interactions is just beginning to be explored. In this review, we discuss some of the most recently developed high-throughput ‘omics’ techniques and their use in the context of host–microbe interaction. Moreover, we highlight studies combining several techniques that are pioneering the integration of ‘omics’ data related to host–microbe interactions. Finally, we list the major challenges ahead for successful systems biology research on host–microbe interactions.
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Affiliation(s)
- Gwendoline Kint
- Centre of Microbial & Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium
| | - Carolina Fierro
- Centre of Microbial & Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium
| | - Kathleen Marchal
- Centre of Microbial & Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium
| | - Jos Vanderleyden
- Centre of Microbial & Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium
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Windle HJ, Brown PA, Kelleher DP. Proteomics of bacterial pathogenicity: therapeutic implications. Proteomics Clin Appl 2010; 4:215-27. [PMID: 21137045 DOI: 10.1002/prca.200900145] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 10/13/2009] [Accepted: 10/19/2009] [Indexed: 01/04/2023]
Abstract
Identification of the molecular mechanisms of host-pathogen interaction is becoming a key focus of proteomics. Analysis of these interactions holds promise for significant developments in the identification of new therapeutic strategies to combat infectious diseases, a process that will also benefit parallel improvements in molecular diagnostics, biomarker identification and drug discovery. This review highlights recent advances in functional proteomics initiatives in infectious disease with emphasis on studies undertaken within physiologically relevant parameters that enable identification of the infectious proteome rather than that of the vegetative state. Deciphering the molecular details of what constitutes physiologically relevant host-pathogen interactions remains an underdeveloped aspect of research into infectious disease. The magnitude of this deficit will be largely influenced by the ease with which model systems can be established to investigate such interactions. As the selective pressures exerted by the host on an infecting pathogen are numerous, the adequacy of certain model systems should be considered carefully.
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Affiliation(s)
- Henry J Windle
- Institute of Molecular Medicine, Trinity College, University of Dublin, Dublin, Ireland.
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Auberry KJ, Kiebel GR, Monroe ME, Adkins JN, Anderson GA, Smith RD. Omics.pnl.gov: A Portal for the Distribution and Sharing of Multi-Disciplinary Pan-Omics Information. ACTA ACUST UNITED AC 2010; 3:1-4. [PMID: 20585472 DOI: 10.4172/jpb.1000114] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ken J Auberry
- Biological Sciences Division, Mail Stop: K8-98, Pacific Northwest National Laboratory, P. O. Box 999, 3335 Q Avenue, Richland, WA 99352
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60
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Charles RC, Harris JB, Chase MR, Lebrun LM, Sheikh A, LaRocque RC, Logvinenko T, Rollins SM, Tarique A, Hohmann EL, Rosenberg I, Krastins B, Sarracino DA, Qadri F, Calderwood SB, Ryan ET. Comparative proteomic analysis of the PhoP regulon in Salmonella enterica serovar Typhi versus Typhimurium. PLoS One 2009; 4:e6994. [PMID: 19746165 PMCID: PMC2736619 DOI: 10.1371/journal.pone.0006994] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 07/24/2009] [Indexed: 12/20/2022] Open
Abstract
Background S. Typhi, a human-restricted Salmonella
enterica serovar, causes a systemic intracellular infection in
humans (typhoid fever). In comparison, S. Typhimurium
causes gastroenteritis in humans, but causes a systemic typhoidal illness in
mice. The PhoP regulon is a well studied two component (PhoP/Q) coordinately
regulated network of genes whose expression is required for intracellular
survival of S. enterica. Methodology/Principal Findings Using high performance liquid chromatography mass spectrometry (HPLC-MS/MS),
we examined the protein expression profiles of three sequenced S.
enterica strains: S. Typhimurium LT2,
S. Typhi CT18, and S. Typhi Ty2 in
PhoP-inducing and non-inducing conditions in vitro and
compared these results to profiles of
phoP−/Q−
mutants derived from S. Typhimurium LT2 and
S. Typhi Ty2. Our analysis identified 53 proteins in
S. Typhimurium LT2 and 56 proteins in
S. Typhi that were regulated in a PhoP-dependent manner. As
expected, many proteins identified in S. Typhi demonstrated
concordant differential expression with a homologous protein in
S. Typhimurium. However, three proteins (HlyE, STY1499, and
CdtB) had no homolog in S. Typhimurium. HlyE is a
pore-forming toxin. STY1499 encodes a stably expressed protein of unknown
function transcribed in the same operon as HlyE. CdtB is a cytolethal
distending toxin associated with DNA damage, cell cycle arrest, and cellular
distension. Gene expression studies confirmed up-regulation of mRNA of HlyE,
STY1499, and CdtB in S. Typhi in PhoP-inducing
conditions. Conclusions/Significance This study is the first protein expression study of the PhoP virulence
associated regulon using strains of Salmonella mutant in
PhoP, has identified three Typhi-unique proteins (CdtB, HlyE and STY1499)
that are not present in the genome of the wide host-range Typhimurium, and
includes the first protein expression profiling of a live attenuated
bacterial vaccine studied in humans (Ty800).
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Affiliation(s)
- Richelle C Charles
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA.
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61
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Shi L, Ansong C, Smallwood H, Rommereim L, McDermott JE, Brewer HM, Norbeck AD, Taylor RC, Gustin JK, Heffron F, Smith RD, Adkins JN. Proteome of Salmonella Enterica Serotype Typhimurium Grown in a Low Mg/pH Medium. ACTA ACUST UNITED AC 2009; 2:388-397. [PMID: 19953200 DOI: 10.4172/jpb.1000099] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
To determine the impact of a low Mg(2+)/pH defined growth medium (MgM) on the proteome of Salmonella enterica serotype Typhimurium, we cultured S. Typhimurium cells in the medium under two different conditions termed MgM Shock and MgM Dilution and then comparatively analyzed the bacterial cells harvested from these conditions by a global proteomic approach. Proteomic results showed that MgM Shock and MgM Dilution differentially affected the S. Typhimurium proteome. MgM Shock induced a group of proteins whose induction usually occurred at low O(2) level, while MgM Dilution induced those related to the type III secretion system (T3SS) of Salmonella Pathogenicity Island 2 (SPI2) and those involved in thiamine or biotin biosynthesis. The metabolic state of the S. Typhimurium cells grown under MgM Shock condition also differed significantly from that under MgM Dilution condition. Western blot analysis not only confirmed the proteomic results, but also showed that the abundances of SPI2-T3SS proteins SsaQ and SseE and biotin biosynthesis proteins BioB and BioD increased after S. Typhimurium infection of RAW 264.7 macrophages. Deletion of the gene encoding BioB reduced the bacterial ability to replicate inside the macrophages, suggesting a biotin-limited environment encountered by S. Typhimurium within RAW 264.7 macrophages.
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Affiliation(s)
- Liang Shi
- Pacific Northwest National Laboratory, Richland, Washington 99352
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62
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Proteogenomic monitoring of Geobacter physiology during stimulated uranium bioremediation. Appl Environ Microbiol 2009; 75:6591-9. [PMID: 19717633 DOI: 10.1128/aem.01064-09] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Implementation of uranium bioremediation requires methods for monitoring the membership and activities of the subsurface microbial communities that are responsible for reduction of soluble U(VI) to insoluble U(IV). Here, we report a proteomics-based approach for simultaneously documenting the strain membership and microbial physiology of the dominant Geobacter community members during in situ acetate amendment of the U-contaminated Rifle, CO, aquifer. Three planktonic Geobacter-dominated samples were obtained from two wells down-gradient of acetate addition. Over 2,500 proteins from each of these samples were identified by matching liquid chromatography-tandem mass spectrometry spectra to peptides predicted from seven isolate Geobacter genomes. Genome-specific peptides indicate early proliferation of multiple M21 and Geobacter bemidjiensis-like strains and later possible emergence of M21 and G. bemidjiensis-like strains more closely related to Geobacter lovleyi. Throughout biostimulation, the proteome is dominated by enzymes that convert acetate to acetyl-coenzyme A and pyruvate for central metabolism, while abundant peptides matching tricarboxylic acid cycle proteins and ATP synthase subunits were also detected, indicating the importance of energy generation during the period of rapid growth following the start of biostimulation. Evolving Geobacter strain composition may be linked to changes in protein abundance over the course of biostimulation and may reflect changes in metabolic functioning. Thus, metagenomics-independent community proteogenomics can be used to diagnose the status of the subsurface consortia upon which remediation biotechnology relies.
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Chowdhury SM, Shi L, Yoon H, Ansong C, Rommereim LM, Norbeck AD, Auberry KJ, Moore RJ, Adkins JN, Heffron F, Smith RD. A method for investigating protein-protein interactions related to salmonella typhimurium pathogenesis. J Proteome Res 2009; 8:1504-14. [PMID: 19206470 DOI: 10.1021/pr800865d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We successfully modified an existing method to investigate protein-protein interactions in the pathogenic bacterium Salmonella enterica serovar Typhimurium (Salmonella Typhimurium). This method includes (i) addition of a histidine-biotin-histidine tag to the bait proteins via recombinant DNA techniques, (ii) in vivo cross-linking with formaldehyde, (iii) tandem affinity purification of bait proteins under fully denaturing conditions, and (iv) identification of the proteins cross-linked to the bait proteins by liquid-chromatography in conjunction with tandem mass-spectrometry. In vivo cross-linking stabilized protein interactions and permitted the subsequent two-step purification step conducted under denaturing conditions. The two-step purification greatly reduced nonspecific binding of noncross-linked proteins to bait proteins. Two different negative controls were employed to eliminate the possibility of identifying background and nonspecific proteins as interacting partners, especially those caused by nonspecific binding to the stationary phase used for protein purification. In an initial demonstration of this approach, we tagged three Salmonella proteinsHimD, PduB and PhoPwith known binding partners that ranged from stable (e.g., HimD) to transient (i.e., PhoP). Distinct sets of interacting proteins were identified for each bait protein, including the known binding partners such as HimA for HimD, as well as unexpected binding partners. Our results suggest that novel protein-protein interactions identified may be critical to pathogenesis by Salmonella.
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Affiliation(s)
- Saiful M Chowdhury
- Pacific Northwest National Laboratory, Richland, Washington 99352, Oregon Health and Science University, Portland, Oregon 97239, USA
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Proteomic investigation of the time course responses of RAW 264.7 macrophages to infection with Salmonella enterica. Infect Immun 2009; 77:3227-33. [PMID: 19528222 DOI: 10.1128/iai.00063-09] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
To investigate the extent to which macrophages respond to Salmonella infection, we infected RAW 264.7 macrophages with Salmonella enterica serotype Typhimurium and analyzed macrophage proteins at various time points following infection by using a global proteomic approach. A total of 1,006 macrophage and 115 Salmonella proteins were identified with high confidence. Most of the Salmonella proteins were observed in the late stage of the infection time course, which is consistent with the fact that the bacterial cells proliferate inside RAW 264.7 macrophages. The peptide abundances of most of the identified macrophage proteins remained relatively constant over the time course of infection. Compared to those of the control, the peptide abundances of 244 macrophage proteins (i.e., 24% of the total identified macrophage proteins) changed significantly after infection. The functions of these Salmonella-affected macrophage proteins were diverse, including production of antibacterial nitric oxide (i.e., inducible nitric oxide synthase), production of prostaglandin H(2) (i.e., cyclooxygenase 2), and regulation of intracellular traffic (e.g., sorting nexin 5 [SNX5], SNX6, and SNX9). Diverse functions of the Salmonella-affected macrophage proteins demonstrate a global macrophage response to Salmonella infection. Western blot analysis not only confirmed the proteomic results for a selected set of proteins but also revealed that (i) the protein abundance of mitochondrial superoxide dismutase increased following macrophage infection, indicating an infection-induced oxidative stress in mitochondria, and (ii) in contrast to infection of macrophages by wild-type Salmonella, infection by the sopB deletion mutant had no negative impact on the abundance of SNX6, suggesting a role for SopB in regulating the abundance of SNX6.
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65
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Taylor RC, Singhal M, Weller J, Khoshnevis S, Shi L, McDermott J. A network inference workflow applied to virulence-related processes in Salmonella typhimurium. Ann N Y Acad Sci 2009; 1158:143-58. [PMID: 19348639 DOI: 10.1111/j.1749-6632.2008.03762.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Inference of the structure of mRNA transcriptional regulatory networks, protein regulatory or interaction networks, and protein activation/inactivation-based signal transduction networks are critical tasks in systems biology. In this article we discuss a workflow for the reconstruction of parts of the transcriptional regulatory network of the pathogenic bacterium Salmonella typhimurium based on the information contained in sets of microarray gene-expression data now available for that organism and describe our results obtained by following this workflow. The primary tool is one of the network-inference algorithms deployed in the Software Environment for Biological Network Inference (SEBINI). Specifically, we selected the algorithm called context likelihood of relatedness (CLR), which uses the mutual information contained in the gene-expression data to infer regulatory connections. The associated analysis pipeline automatically stores the inferred edges from the CLR runs within SEBINI and, upon request, transfers the inferred edges into either Cytoscape or the plug-in Collective Analysis of Biological Interaction Networks (CABIN) tool for further postanalysis of the inferred regulatory edges. The following article presents the outcome of this workflow, as well as the protocols followed for microarray data collection, data cleansing, and network inference. Our analysis revealed several interesting interactions, functional groups, metabolic pathways, and regulons in S. typhimurium.
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Affiliation(s)
- Ronald C Taylor
- Computational Biology & Bioinformatics Group, Pacific Northwest National Laboratory (U.S. Dept of Energy), Richland, Washington, USA.
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66
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Constraint-based analysis of metabolic capacity of Salmonella typhimurium during host-pathogen interaction. BMC SYSTEMS BIOLOGY 2009; 3:38. [PMID: 19356237 PMCID: PMC2678070 DOI: 10.1186/1752-0509-3-38] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Accepted: 04/08/2009] [Indexed: 01/10/2023]
Abstract
BACKGROUND Infections with Salmonella cause significant morbidity and mortality worldwide. Replication of Salmonella typhimurium inside its host cell is a model system for studying the pathogenesis of intracellular bacterial infections. Genome-scale modeling of bacterial metabolic networks provides a powerful tool to identify and analyze pathways required for successful intracellular replication during host-pathogen interaction. RESULTS We have developed and validated a genome-scale metabolic network of Salmonella typhimurium LT2 (iRR1083). This model accounts for 1,083 genes that encode proteins catalyzing 1,087 unique metabolic and transport reactions in the bacterium. We employed flux balance analysis and in silico gene essentiality analysis to investigate growth under a wide range of conditions that mimic in vitro and host cell environments. Gene expression profiling of S. typhimurium isolated from macrophage cell lines was used to constrain the model to predict metabolic pathways that are likely to be operational during infection. CONCLUSION Our analysis suggests that there is a robust minimal set of metabolic pathways that is required for successful replication of Salmonella inside the host cell. This model also serves as platform for the integration of high-throughput data. Its computational power allows identification of networked metabolic pathways and generation of hypotheses about metabolism during infection, which might be used for the rational design of novel antibiotics or vaccine strains.
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Ansong C, Yoon H, Porwollik S, Mottaz-Brewer H, Petritis BO, Jaitly N, Adkins JN, McClelland M, Heffron F, Smith RD. Global systems-level analysis of Hfq and SmpB deletion mutants in Salmonella: implications for virulence and global protein translation. PLoS One 2009; 4:e4809. [PMID: 19277208 PMCID: PMC2652828 DOI: 10.1371/journal.pone.0004809] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Accepted: 02/02/2009] [Indexed: 11/19/2022] Open
Abstract
Using sample-matched transcriptomics and proteomics measurements it is now possible to begin to understand the impact of post-transcriptional regulatory programs in Enterobacteria. In bacteria post-transcriptional regulation is mediated by relatively few identified RNA-binding protein factors including CsrA, Hfq and SmpB. A mutation in any one of these three genes, csrA, hfq, and smpB, in Salmonella is attenuated for mouse virulence and unable to survive in macrophages. CsrA has a clearly defined specificity based on binding to a specific mRNA sequence to inhibit translation. However, the proteins regulated by Hfq and SmpB are not as clearly defined. Previous work identified proteins regulated by hfq using purification of the RNA-protein complex with direct sequencing of the bound RNAs and found binding to a surprisingly large number of transcripts. In this report we have used global proteomics to directly identify proteins regulated by Hfq or SmpB by comparing protein abundance in the parent and isogenic hfq or smpB mutant. From these same samples we also prepared RNA for microarray analysis to determine if alteration of protein expression was mediated post-transcriptionally. Samples were analyzed from bacteria grown under four different conditions; two laboratory conditions and two that are thought to mimic the intracellular environment. We show that mutants of hfq and smpB directly or indirectly modulate at least 20% and 4% of all possible Salmonella proteins, respectively, with limited correlation between transcription and protein expression. These proteins represent a broad spectrum of Salmonella proteins required for many biological processes including host cell invasion, motility, central metabolism, LPS biosynthesis, two-component regulatory systems, and fatty acid metabolism. Our results represent one of the first global analyses of post-transcriptional regulons in any organism and suggest that regulation at the translational level is widespread and plays an important role in virulence regulation and environmental adaptation for Salmonella.
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Affiliation(s)
- Charles Ansong
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Hyunjin Yoon
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon, United States of America
| | - Steffen Porwollik
- The Sidney Kimmel Cancer Center, San Diego, California, United States of America
| | - Heather Mottaz-Brewer
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Brianne O. Petritis
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Navdeep Jaitly
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Joshua N. Adkins
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Michael McClelland
- The Sidney Kimmel Cancer Center, San Diego, California, United States of America
| | - Fred Heffron
- Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, Oregon, United States of America
| | - Richard D. Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America
- * E-mail:
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68
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Yoon H, McDermott JE, Porwollik S, McClelland M, Heffron F. Coordinated regulation of virulence during systemic infection of Salmonella enterica serovar Typhimurium. PLoS Pathog 2009; 5:e1000306. [PMID: 19229334 PMCID: PMC2639726 DOI: 10.1371/journal.ppat.1000306] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Accepted: 01/22/2009] [Indexed: 11/18/2022] Open
Abstract
To cause a systemic infection, Salmonella must respond to many environmental cues during mouse infection and express specific subsets of genes in a temporal and spatial manner, but the regulatory pathways are poorly established. To unravel how micro-environmental signals are processed and integrated into coordinated action, we constructed in-frame non-polar deletions of 83 regulators inferred to play a role in Salmonella enteriditis Typhimurium (STM) virulence and tested them in three virulence assays (intraperitoneal [i.p.], and intragastric [i.g.] infection in BALB/c mice, and persistence in 129X1/SvJ mice). Overall, 35 regulators were identified whose absence attenuated virulence in at least one assay, and of those, 14 regulators were required for systemic mouse infection, the most stringent virulence assay. As a first step towards understanding the interplay between a pathogen and its host from a systems biology standpoint, we focused on these 14 genes. Transcriptional profiles were obtained for deletions of each of these 14 regulators grown under four different environmental conditions. These results, as well as publicly available transcriptional profiles, were analyzed using both network inference and cluster analysis algorithms. The analysis predicts a regulatory network in which all 14 regulators control the same set of genes necessary for Salmonella to cause systemic infection. We tested the regulatory model by expressing a subset of the regulators in trans and monitoring transcription of 7 known virulence factors located within Salmonella pathogenicity island 2 (SPI-2). These experiments validated the regulatory model and showed that the response regulator SsrB and the MarR type regulator, SlyA, are the terminal regulators in a cascade that integrates multiple signals. Furthermore, experiments to demonstrate epistatic relationships showed that SsrB can replace SlyA and, in some cases, SlyA can replace SsrB for expression of SPI-2 encoded virulence factors.
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Affiliation(s)
- Hyunjin Yoon
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Jason E. McDermott
- Pacific Northwest National Laboratories, Richland, Washington, United States of America
| | - Steffen Porwollik
- The Sydney Kimmel Cancer Center, San Diego, California, United States of America
| | - Michael McClelland
- The Sydney Kimmel Cancer Center, San Diego, California, United States of America
| | - Fred Heffron
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, United States of America
- * E-mail:
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69
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Rodland KD, Adkins JN, Ansong C, Chowdhury S, Manes NP, Shi L, Yoon H, Smith RD, Heffron F. Use of high-throughput mass spectrometry to elucidate host-pathogen interactions in Salmonella. Future Microbiol 2009; 3:625-34. [PMID: 19072180 DOI: 10.2217/17460913.3.6.625] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Capabilities in mass spectrometry are evolving rapidly, with recent improvements in sensitivity, data analysis and, most important from the standpoint of this review, much higher throughput, allowing analysis of many samples in a single day. This short review describes how these improvements in mass spectrometry can be used to dissect host-pathogen interactions using Salmonella as a model system. This approach has enabled direct identification of the majority of annotated Salmonella proteins, quantitation of expression changes under various in vitro growth conditions and new insights into virulence and expression of Salmonella proteins within host cells. One of the most significant findings is that a relatively high percentage of all the annotated genes (>20%) in Salmonella are regulated post-transcriptionally. In addition, new and unexpected interactions have been identified for several Salmonella virulence regulators that involve protein-protein interactions, suggesting additional functions of these regulators in coordinating virulence expression. Overall high-throughput mass spectrometry provides a new view of host-pathogen interactions, emphasizing the protein products and defining how protein interactions determine the outcome of infection.
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Affiliation(s)
- Karin D Rodland
- Pacific Northwest National Laboratory, Richland, WA 99354, USA.
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70
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Sonck KAJ, Kint G, Schoofs G, Vander Wauven C, Vanderleyden J, De Keersmaecker SCJ. The proteome of Salmonella Typhimurium grown under in vivo-mimicking conditions. Proteomics 2009; 9:565-79. [DOI: 10.1002/pmic.200700476] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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71
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Bottlenecks and Hubs in Inferred Networks Are Important for Virulence in Salmonella typhimurium. J Comput Biol 2009; 16:169-80. [DOI: 10.1089/cmb.2008.04tt] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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72
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Hixson KK. Label-free relative quantitation of prokaryotic proteomes using the accurate mass and time tag approach. Methods Mol Biol 2009; 492:39-63. [PMID: 19241026 DOI: 10.1007/978-1-59745-493-3_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Prokaryotic protein expression changes in detectable amounts due to the environmental stimuli encountered by the organism. To understand the underlying mechanisms involved it is necessary to comprehensively detect both the proteins present and their relative abundance under the growth conditions of interest. LC-MS based accurate mass and time (AMT) tag method along with the use of clustering software can provide a visual and more comprehensive understanding of significant protein abundance increases and decreases. These data then can be effectively used to pin-point proteins of interest for further genetic and physiological studies. This method allows for the identification and quantitation of thousands of proteins in a single mass spectrometric analysis and is more comprehensive than two dimensional electrophoresis and shotgun approaches.
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Affiliation(s)
- Kim K Hixson
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
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73
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Wilson JW, Ott CM, Quick L, Davis R, zu Bentrup KH, Crabbé A, Richter E, Sarker S, Barrila J, Porwollik S, Cheng P, McClelland M, Tsaprailis G, Radabaugh T, Hunt A, Shah M, Nelman-Gonzalez M, Hing S, Parra M, Dumars P, Norwood K, Bober R, Devich J, Ruggles A, CdeBaca A, Narayan S, Benjamin J, Goulart C, Rupert M, Catella L, Schurr MJ, Buchanan K, Morici L, McCracken J, Porter MD, Pierson DL, Smith SM, Mergeay M, Leys N, Stefanyshyn-Piper HM, Gorie D, Nickerson CA. Media ion composition controls regulatory and virulence response of Salmonella in spaceflight. PLoS One 2008; 3:e3923. [PMID: 19079590 PMCID: PMC2592540 DOI: 10.1371/journal.pone.0003923] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Accepted: 11/03/2008] [Indexed: 12/17/2022] Open
Abstract
The spaceflight environment is relevant to conditions encountered by pathogens during the course of infection and induces novel changes in microbial pathogenesis not observed using conventional methods. It is unclear how microbial cells sense spaceflight-associated changes to their growth environment and orchestrate corresponding changes in molecular and physiological phenotypes relevant to the infection process. Here we report that spaceflight-induced increases in Salmonella virulence are regulated by media ion composition, and that phosphate ion is sufficient to alter related pathogenesis responses in a spaceflight analogue model. Using whole genome microarray and proteomic analyses from two independent Space Shuttle missions, we identified evolutionarily conserved molecular pathways in Salmonella that respond to spaceflight under all media compositions tested. Identification of conserved regulatory paradigms opens new avenues to control microbial responses during the infection process and holds promise to provide an improved understanding of human health and disease on Earth.
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Affiliation(s)
- James W. Wilson
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, Arizona, United States of America
- Department of Biology, Villanova University, Villanova, Pennsylvania, United States of America
| | - C. Mark Ott
- Habitability and Environmental Factors Division, NASA-Johnson Space Center, Houston, Texas, United States of America
| | - Laura Quick
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, Arizona, United States of America
- Department of Biology, Villanova University, Villanova, Pennsylvania, United States of America
| | - Richard Davis
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, Arizona, United States of America
| | | | - Aurélie Crabbé
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, Arizona, United States of America
- Flanders Institute of Biotechnology, Free University of Brussels, Brussels, Belgium
- Belgian Nuclear Research Center, Mol, Belgium
| | - Emily Richter
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, Arizona, United States of America
| | - Shameema Sarker
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, Arizona, United States of America
| | - Jennifer Barrila
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, Arizona, United States of America
| | - Steffen Porwollik
- Sidney Kimmel Cancer Center, San Diego, California, United States of America
| | - Pui Cheng
- Sidney Kimmel Cancer Center, San Diego, California, United States of America
| | - Michael McClelland
- Sidney Kimmel Cancer Center, San Diego, California, United States of America
| | - George Tsaprailis
- Center for Toxicology, University of Arizona, Tucson, Arizona, United States of America
| | - Timothy Radabaugh
- Center for Toxicology, University of Arizona, Tucson, Arizona, United States of America
| | - Andrea Hunt
- Center for Toxicology, University of Arizona, Tucson, Arizona, United States of America
| | - Miti Shah
- The Biodesign Institute, Center for Glycoscience Technology, Arizona State University, Tempe, Arizona, United States of America
| | | | - Steve Hing
- NASA-Ames Research Center, Moffett Field, California, United States of America
| | - Macarena Parra
- NASA-Ames Research Center, Moffett Field, California, United States of America
| | - Paula Dumars
- NASA-Ames Research Center, Moffett Field, California, United States of America
| | - Kelly Norwood
- Space Life Sciences Lab, Kennedy Space Center, Cape Canaveral, Florida, United States of America
| | - Ramona Bober
- Space Life Sciences Lab, Kennedy Space Center, Cape Canaveral, Florida, United States of America
| | - Jennifer Devich
- Space Life Sciences Lab, Kennedy Space Center, Cape Canaveral, Florida, United States of America
| | - Ashleigh Ruggles
- Space Life Sciences Lab, Kennedy Space Center, Cape Canaveral, Florida, United States of America
| | - Autumn CdeBaca
- Space Life Sciences Lab, Kennedy Space Center, Cape Canaveral, Florida, United States of America
| | - Satro Narayan
- Space Life Sciences Lab, Kennedy Space Center, Cape Canaveral, Florida, United States of America
| | - Joseph Benjamin
- Space Life Sciences Lab, Kennedy Space Center, Cape Canaveral, Florida, United States of America
| | - Carla Goulart
- BioServe, University of Colorado, Boulder, Colorado, United States of America
| | - Mark Rupert
- BioServe, University of Colorado, Boulder, Colorado, United States of America
| | - Luke Catella
- Space Life Sciences Lab, Kennedy Space Center, Cape Canaveral, Florida, United States of America
| | - Michael J. Schurr
- School of Medicine, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Kent Buchanan
- Oklahoma City University, Oklahoma City, Oklahoma, United States of America
| | - Lisa Morici
- Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - James McCracken
- Section of General Surgery, University of Chicago, Chicago, Illinois, United States of America
| | - Marc D. Porter
- Departments of Chemistry, Chemical Engineering and Bioengineering, University of Utah, Salt Lake City, Utah, United States of America
| | - Duane L. Pierson
- Habitability and Environmental Factors Division, NASA-Johnson Space Center, Houston, Texas, United States of America
| | - Scott M. Smith
- Human Adaptation and Countermeasures Division, Johnson Space Center, National Aeronautics and Space Administration, Houston, Texas, United States of America
| | - Max Mergeay
- Belgian Nuclear Research Center, Mol, Belgium
| | | | | | - Dominic Gorie
- Astronaut Office, NASA-Johnson Space Center, Houston, Texas, United States of America
| | - Cheryl A. Nickerson
- The Biodesign Institute, Center for Infectious Diseases and Vaccinology, Arizona State University, Tempe, Arizona, United States of America
- * E-mail:
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74
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Crowley CS, Sawaya MR, Bobik TA, Yeates TO. Structure of the PduU shell protein from the Pdu microcompartment of Salmonella. Structure 2008; 16:1324-32. [PMID: 18786396 PMCID: PMC5878062 DOI: 10.1016/j.str.2008.05.013] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Revised: 05/29/2008] [Accepted: 05/30/2008] [Indexed: 01/07/2023]
Abstract
The Pdu microcompartment is a proteinaceous, subcellular structure that serves as an organelle for the metabolism of 1,2-propanediol in Salmonella enterica. It encapsulates several related enzymes within a shell composed of a few thousand protein subunits. Recent structural studies on the carboxysome, a related microcompartment involved in CO(2) fixation, have concluded that the major shell proteins from that microcompartment form hexamers that pack into layers comprising the facets of the shell. Here we report the crystal structure of PduU, a protein from the Pdu microcompartment, representing the first structure of a shell protein from a noncarboxysome microcompartment. Though PduU is a hexamer like other characterized shell proteins, it has undergone a circular permutation leading to dramatic differences in the hexamer pore. In view of the hypothesis that microcompartment metabolites diffuse across the outer shell through these pores, the unique structure of PduU suggests the possibility of a special functional role.
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Affiliation(s)
- Christopher S. Crowley
- UCLA Molecular Biology Institute; University of California, Los Angeles (UCLA); Los Angeles, CA, 90095; USA
| | - Michael R. Sawaya
- UCLA-DOE Institute for Genomics and Proteomics; UCLA; Los Angeles, CA, 90095; USA
| | - Thomas A. Bobik
- Department of Biochemistry, Biophysics and Molecular Biology; Iowa State University; Ames, IA, 50011; USA
| | - Todd O. Yeates
- UCLA Molecular Biology Institute; University of California, Los Angeles (UCLA); Los Angeles, CA, 90095; USA,UCLA-DOE Institute for Genomics and Proteomics; UCLA; Los Angeles, CA, 90095; USA,UCLA Department of Chemistry and Biochemistry; UCLA; Los Angeles, CA, 90095; USA
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75
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Sowell SM, Wilhelm LJ, Norbeck AD, Lipton MS, Nicora CD, Barofsky DF, Carlson CA, Smith RD, Giovanonni SJ. Transport functions dominate the SAR11 metaproteome at low-nutrient extremes in the Sargasso Sea. ISME JOURNAL 2008; 3:93-105. [PMID: 18769456 DOI: 10.1038/ismej.2008.83] [Citation(s) in RCA: 245] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The northwestern Sargasso Sea undergoes annual cycles of productivity with increased production in spring corresponding to periods of upwelling, and oligotrophy in summer and autumn, when the water column becomes highly stratified. The biological productivity of this region is reduced during stratified periods as a result of low concentrations of phosphorus and nitrogen in the euphotic zone. To better understand the mechanisms of microbial survival in this oligotrophic environment, we used capillary liquid chromatography (LC)-tandem mass spectrometry to detect microbial proteins in surface samples collected in September 2005. A total of 2215 peptides that mapped to 236 SAR11 proteins, 1911 peptides that mapped to 402 Prochlorococcus proteins and 2407 peptides that mapped to 404 Synechococcus proteins were detected. Mass spectra from SAR11 periplasmic substrate-binding proteins accounted for a disproportionately large fraction of the peptides detected, consistent with observations that these extremely small cells devote a large proportion of their volume to periplasm. Abundances were highest for periplasmic substrate-binding proteins for phosphate, amino acids, phosphonate, sugars and spermidine. Proteins implicated in the prevention of oxidative damage and protein refolding were also abundant. Our findings support the view that competition for multiple nutrients in oligotrophic systems is extreme, but nutrient flux is sufficient to sustain microbial community activity.
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Affiliation(s)
- Sarah M Sowell
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR 97331, USA
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76
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Proteomic analysis of and immune responses to Ehrlichia chaffeensis lipoproteins. Infect Immun 2008; 76:3405-14. [PMID: 18490460 DOI: 10.1128/iai.00056-08] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ehrlichia chaffeensis is an obligately intracellular gram-negative bacterium and is the etiologic agent of human monocytic ehrlichiosis (HME). Although E. chaffeensis induces the generation of several cytokines and chemokines by leukocytes, E. chaffeensis lacks lipopolysaccharide and peptidoglycan. Bioinfomatic analysis of the E. chaffeensis genome, however, predicted genes encoding 15 lipoproteins and 3 posttranslational lipoprotein-processing enzymes. The present study showed that by use of multidimensional liquid chromatography followed by tandem mass spectrometry, all predicted lipoproteins as well as lipoprotein-processing enzymes were expressed by E. chaffeensis cultured in the human promyelocytic leukemia cell line HL-60. Consistent with this observation, a signal peptidase II inhibitor, globomycin, was found to inhibit E. chaffeensis infection and lipoprotein processing in HL-60 cell culture. To study in vivo E. chaffeensis lipoprotein expression and host immune responses to E. chaffeensis lipoproteins, 13 E. chaffeensis lipoprotein genes were cloned into a mammalian expression vector. When the DNA constructs were inoculated into naïve dogs, or when dogs were infected with E. chaffeensis, the animals developed delayed-type hypersensitivity reactions at cutaneous sites of the DNA construct deposition and serum antibodies to these lipoproteins. This is the first demonstration of lipoprotein expression and elicitation of immune responses by a member of the order Rickettsiales. Multiple lipoproteins expressed by E. chaffeensis in vitro and in vivo may play key roles in pathogenesis and immune responses in HME.
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77
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Proteomic analysis of stationary phase in the marine bacterium "Candidatus Pelagibacter ubique". Appl Environ Microbiol 2008; 74:4091-100. [PMID: 18469119 DOI: 10.1128/aem.00599-08] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
"Candidatus Pelagibacter ubique," an abundant marine alphaproteobacterium, subsists in nature at low ambient nutrient concentrations and may often be exposed to nutrient limitation, but its genome reveals no evidence of global regulatory mechanisms for adaptation to stationary phase. High-resolution capillary liquid chromatography coupled online to an LTQ mass spectrometer was used to build an accurate mass and time (AMT) tag library that enabled quantitative examination of proteomic differences between exponential- and stationary-phase "Ca. Pelagibacter ubique" cells cultivated in a seawater medium. The AMT tag library represented 65% of the predicted protein-encoding genes. "Ca. Pelagibacter ubique" appears to respond adaptively to stationary phase by increasing the abundance of a suite of proteins that contribute to homeostasis rather than undergoing a major remodeling of its proteome. Stationary-phase abundances increased significantly for OsmC and thioredoxin reductase, which may mitigate oxidative damage in "Ca. Pelagibacter," as well as for molecular chaperones, enzymes involved in methionine and cysteine biosynthesis, proteins involved in rho-dependent transcription termination, and the signal transduction enzyme CheY-FisH. We speculate that this limited response may enable "Ca. Pelagibacter ubique" to cope with ambient conditions that deprive it of nutrients for short periods and, furthermore, that the ability to resume growth overrides the need for a more comprehensive global stationary-phase response to create a capacity for long-term survival.
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78
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Webb-Robertson BJM, Cannon WR, Oehmen CS, Shah AR, Gurumoorthi V, Lipton MS, Waters KM. A support vector machine model for the prediction of proteotypic peptides for accurate mass and time proteomics. ACTA ACUST UNITED AC 2008; 24:1503-9. [PMID: 18453551 DOI: 10.1093/bioinformatics/btn218] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
MOTIVATION The standard approach to identifying peptides based on accurate mass and elution time (AMT) compares profiles obtained from a high resolution mass spectrometer to a database of peptides previously identified from tandem mass spectrometry (MS/MS) studies. It would be advantageous, with respect to both accuracy and cost, to only search for those peptides that are detectable by MS (proteotypic). RESULTS We present a support vector machine (SVM) model that uses a simple descriptor space based on 35 properties of amino acid content, charge, hydrophilicity and polarity for the quantitative prediction of proteotypic peptides. Using three independently derived AMT databases (Shewanella oneidensis, Salmonella typhimurium, Yersinia pestis) for training and validation within and across species, the SVM resulted in an average accuracy measure of 0.8 with a SD of <0.025. Furthermore, we demonstrate that these results are achievable with a small set of 12 variables and can achieve high proteome coverage. AVAILABILITY http://omics.pnl.gov/software/STEPP.php. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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79
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Callister SJ, McCue LA, Turse JE, Monroe ME, Auberry KJ, Smith RD, Adkins JN, Lipton MS. Comparative bacterial proteomics: analysis of the core genome concept. PLoS One 2008; 3:e1542. [PMID: 18253490 PMCID: PMC2213561 DOI: 10.1371/journal.pone.0001542] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Accepted: 01/09/2008] [Indexed: 11/25/2022] Open
Abstract
While comparative bacterial genomic studies commonly predict a set of genes indicative of common ancestry, experimental validation of the existence of this core genome requires extensive measurement and is typically not undertaken. Enabled by an extensive proteome database developed over six years, we have experimentally verified the expression of proteins predicted from genomic ortholog comparisons among 17 environmental and pathogenic bacteria. More exclusive relationships were observed among the expressed protein content of phenotypically related bacteria, which is indicative of the specific lifestyles associated with these organisms. Although genomic studies can establish relative orthologous relationships among a set of bacteria and propose a set of ancestral genes, our proteomics study establishes expressed lifestyle differences among conserved genes and proposes a set of expressed ancestral traits.
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Affiliation(s)
- Stephen J. Callister
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Lee Ann McCue
- Computational Sciences and Mathematics Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Joshua E. Turse
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Matthew E. Monroe
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Kenneth J. Auberry
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Richard D. Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Joshua N. Adkins
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America
- * To whom correspondence should be addressed. E-mail: (JA); (ML)
| | - Mary S. Lipton
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America
- * To whom correspondence should be addressed. E-mail: (JA); (ML)
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80
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Wu HJ, Wang AHJ, Jennings MP. Discovery of virulence factors of pathogenic bacteria. Curr Opin Chem Biol 2008; 12:93-101. [DOI: 10.1016/j.cbpa.2008.01.023] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Accepted: 01/15/2008] [Indexed: 01/10/2023]
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81
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Manes NP, Estep RD, Mottaz HM, Moore RJ, Clauss TRW, Monroe ME, Du X, Adkins JN, Wong SW, Smith RD. Comparative proteomics of human monkeypox and vaccinia intracellular mature and extracellular enveloped virions. J Proteome Res 2008; 7:960-8. [PMID: 18205298 DOI: 10.1021/pr070432+] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Orthopoxviruses are among the largest and most complex of the animal viruses. In response to the recent emergence of monkeypox in Africa and the threat of smallpox bioterrorism, two orthopoxviruses with different pathogenic potentials, human monkeypox virus and vaccinia virus, were proteomically compared with the goal of identifying proteins required for pathogenesis. Orthopoxviruses were grown in HeLa cells to two different viral forms (intracellular mature virus and extracellular enveloped virus), purified by sucrose gradient ultracentrifugation, denatured using RapiGest surfactant, and digested with trypsin. Unfractionated samples and strong cation exchange HPLC fractions were analyzed by high-resolution reversed-phase nano-LC-MS/MS, and analyses of the MS/MS spectra using SEQUEST and X! Tandem resulted in the confident identification of hundreds of monkeypox, vaccinia, and copurified host-cell proteins. The unfractionated samples were additionally analyzed by LC-MS using an LTQ-Orbitrap, and the accurate mass and elution time tag approach was used to perform quantitative comparisons. Possible pathophysiological roles of differentially abundant Orthopoxvirus proteins are discussed. Data, processed results, and protocols are available at http://www.proteomicsresource.org/.
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Affiliation(s)
- Nathan P Manes
- Fundamental Science Division and Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
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82
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Alix E, Blanc-Potard AB. Peptide-assisted degradation of the Salmonella MgtC virulence factor. EMBO J 2008; 27:546-57. [PMID: 18200043 DOI: 10.1038/sj.emboj.7601983] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Accepted: 12/20/2007] [Indexed: 01/04/2023] Open
Abstract
MgtC is a virulence factor common to several intracellular pathogens that is required for intramacrophage survival and growth in magnesium-depleted medium. In Salmonella enterica, MgtC is coexpressed with the MgtB magnesium transporter and transcription of the mgtCB operon is induced by magnesium deprivation. Despite the high level of mgtCB transcriptional induction in magnesium-depleted medium, the MgtC protein is hardly detected in a wild-type Salmonella strain. Here, we show that downregulation of MgtC expression is dependent on a hydrophobic peptide, MgtR, which is encoded by the mgtCB operon. Our results suggest that MgtR promotes MgtC degradation by the FtsH protease, providing a negative regulatory feedback. Bacterial two-hybrid assays demonstrate that MgtR interacts with the inner-membrane MgtC protein. We identified mutant derivatives of MgtR and MgtC that prevent both regulation and interaction between the two partners. In macrophages, overexpression of the MgtR peptide led to a decrease of the replication rate of Salmonella. This study highlights the role of peptides in bacterial regulatory mechanisms and provides a natural antagonist of the MgtC virulence factor.
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83
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Zhang C, Crasta O, Cammer S, Will R, Kenyon R, Sullivan D, Yu Q, Sun W, Jha R, Liu D, Xue T, Zhang Y, Moore M, McGarvey P, Huang H, Chen Y, Zhang J, Mazumder R, Wu C, Sobral B. An emerging cyberinfrastructure for biodefense pathogen and pathogen-host data. Nucleic Acids Res 2008; 36:D884-91. [PMID: 17984082 PMCID: PMC2239001 DOI: 10.1093/nar/gkm903] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Revised: 10/04/2007] [Accepted: 10/05/2007] [Indexed: 01/07/2023] Open
Abstract
The NIAID-funded Biodefense Proteomics Resource Center (RC) provides storage, dissemination, visualization and analysis capabilities for the experimental data deposited by seven Proteomics Research Centers (PRCs). The data and its publication is to support researchers working to discover candidates for the next generation of vaccines, therapeutics and diagnostics against NIAID's Category A, B and C priority pathogens. The data includes transcriptional profiles, protein profiles, protein structural data and host-pathogen protein interactions, in the context of the pathogen life cycle in vivo and in vitro. The database has stored and supported host or pathogen data derived from Bacillus, Brucella, Cryptosporidium, Salmonella, SARS, Toxoplasma, Vibrio and Yersinia, human tissue libraries, and mouse macrophages. These publicly available data cover diverse data types such as mass spectrometry, yeast two-hybrid (Y2H), gene expression profiles, X-ray and NMR determined protein structures and protein expression clones. The growing database covers over 23 000 unique genes/proteins from different experiments and organisms. All of the genes/proteins are annotated and integrated across experiments using UniProt Knowledgebase (UniProtKB) accession numbers. The web-interface for the database enables searching, querying and downloading at the level of experiment, group and individual gene(s)/protein(s) via UniProtKB accession numbers or protein function keywords. The system is accessible at http://www.proteomicsresource.org/.
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Affiliation(s)
- C. Zhang
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - O. Crasta
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - S. Cammer
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - R. Will
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - R. Kenyon
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - D. Sullivan
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - Q. Yu
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - W. Sun
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - R. Jha
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - D. Liu
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - T. Xue
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - Y. Zhang
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - M. Moore
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - P. McGarvey
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - H. Huang
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - Y. Chen
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - J. Zhang
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - R. Mazumder
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - C. Wu
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
| | - B. Sobral
- Virginia Bioinformatics Institute at Virginia Polytechnic Institute and State University, Washington Street (0477), Blacksburg, VA 24061, Social & Scientific Systems, Inc., 8757 Georgia Avenue, 12th Floor Silver Spring, MD 20910 and Protein Information Resource, Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3300 Whitehaven Street NW, Suite 1200, Washington, DC 20007, USA
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84
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Ansong C, Yoon H, Norbeck AD, Gustin JK, McDermott JE, Mottaz HM, Rue J, Adkins JN, Heffron F, Smith RD. Proteomics analysis of the causative agent of typhoid fever. J Proteome Res 2008; 7:546-57. [PMID: 18166006 DOI: 10.1021/pr070434u] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Typhoid fever is a potentially fatal disease caused by the bacterial pathogen Salmonella enterica serotype Typhi ( S. typhi). S. typhi infection is a complex process that involves numerous bacterially encoded virulence determinants, and these are thought to confer both stringent human host specificity and a high mortality rate. In the present study, we used a liquid chromatography-mass spectrometry (LC-MS)-based proteomics strategy to investigate the proteome of logarithmic, stationary phase, and low pH/low magnesium (MgM) S. typhi cultures. This represents the first large-scale comprehensive characterization of the S. typhi proteome. Our analysis identified a total of 2066 S. typhi proteins. In an effort to identify putative S. typhi-specific virulence factors, we then compared our S. typhi results to those obtained in a previously published study of the S. typhimurium proteome under similar conditions ( Adkins, J. N. et al. Mol. Cell. Proteomics 2006, 5, 1450-1461 ). Comparative proteomics analysis of S. typhi strain Ty2 and S. typhimurium strain LT2 revealed a subset of highly expressed proteins unique to S. typhi that were exclusively detected under conditions that are thought to mimic the infective state in macrophage cells. These proteins included CdtB, HlyE, and gene products of t0142, t1108, t1109, t1476, and t1602. The differential expression of T1108, T1476, and HlyE was confirmed by Western blot analysis. When our observations are taken together with the current literature, they suggest that this subset of proteins may play a role in S. typhi pathogenesis and human host specificity.
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Affiliation(s)
- Charles Ansong
- Biological Sciences Division, and Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
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85
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Schmidt LD, Kohrt LJ, Brown DR. Comparison of growth phase on Salmonella enterica serovar Typhimurium invasion in an epithelial cell line (IPEC J2) and mucosal explants from porcine small intestine. Comp Immunol Microbiol Infect Dis 2008; 31:63-9. [PMID: 17544508 PMCID: PMC10656783 DOI: 10.1016/j.cimid.2007.04.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2007] [Indexed: 11/26/2022]
Abstract
Salmonella Typhimurium DT104 is a zoonotic enteropathogen of increasing concern for human health. In this study, the influence of growth phase on invasiveness of a S. Typhimurium DT104 field isolate and two reference strains (SL1344 and ATCC 14028) was compared in IPEC J2 cells and mucosal explants from porcine ileum. Internalized bacteria were quantified by a gentamicin resistance assay. After 90 min of exposure to the apical aspect of epithelial monolayers or luminal surface of explants, internalization of all S. Typhimurium strains in mid-logarithmic phase of bacterial growth was comparable. Internalization of stationary phase bacteria was reduced relative to log phase bacteria, with DT104 exhibiting the greatest decrease. Growth phase-related differences in S. Typhimurium invasion are similar in porcine intestinal epithelial cells and mucosal explants, but may be greater in multidrug-resistant strains.
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Affiliation(s)
- Lisa D. Schmidt
- Department of Veterinary and Biomedical Sciences, University of Minnesota, 1988 Fitch Avenue, St. Paul, Minnesota 55108-6010
| | - Laura J. Kohrt
- Department of Veterinary and Biomedical Sciences, University of Minnesota, 1988 Fitch Avenue, St. Paul, Minnesota 55108-6010
| | - David R. Brown
- Department of Veterinary and Biomedical Sciences, University of Minnesota, 1988 Fitch Avenue, St. Paul, Minnesota 55108-6010
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86
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Klumpp J, Fuchs TM. Identification of novel genes in genomic islands that contribute to Salmonella typhimurium replication in macrophages. MICROBIOLOGY-SGM 2007; 153:1207-1220. [PMID: 17379730 DOI: 10.1099/mic.0.2006/004747-0] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Salmonella enterica serovar Typhimurium (S. typhimurium) survives and proliferates within macrophage cells. A mutant library of strain ATCC 14028 based on gene disruption by homologous recombination was screened in order to identify genes that are required for wild-type-like intracellular replication. Randomly generated chromosomal fragments from the genome of S. typhimurium were cloned into a temperature-sensitive vector, and approximately 8000 individual mutant clones were obtained by insertional-duplication mutagenesis (IDM) upon selection at non-permissive temperature. Large-scale screening for replication defects in mouse macrophages, but not during growth in rich or minimal medium, revealed a set of attenuated mutants that were further characterized by PCR amplification and sequencing of the mutagenic fragments. Following analysis of a Salmonella genome map with the annotated positions of vector insertions, an accumulation of 33 attenuating insertions within genes of ten non-collinear regions was found. Insertions in virK, gipA and five SPI-2 genes as well as seven non-polar deletions validated the screen. No invasion deficiencies of the mutants were observed. The cob-cbi-pdu cluster containing the genes for cobalamin synthesis and 1,2-propanediol degradation was shown to be required for Salmonella replication within macrophages. These data gave rise to a model of eukaryotic glycoconjugates and phospholipids as alternative carbon, nitrogen and energy sources for intracellularly replicating bacteria. The contribution of as yet unknown components of SPI-6 and the Gifsy-1 and Gifsy-2 prophage islands to intracellular replication is reported, as well as the fivefold reduced intracellular growth rate of a mutant with a deletion of STM1677, which probably encodes a LysR-like transcriptional regulator. The intracellular replication rate of three double mutants, each lacking two gene products of the cob-cbi-pdu cluster or the Gifsy-1 prophage, was shown to be lower than that of the respective single mutants, suggesting that additive effects of subtle intracellular advantages contribute to Salmonella fitness in vivo.
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Affiliation(s)
- Jochen Klumpp
- Institute of Food Science and Nutrition, ETH Zürich, Schmelzbergstr. 7, 8092 Zürich, Switzerland
- Zentralinstitut für Ernährungs- und Lebensmittelforschung (ZIEL), Abteilung Mikrobiologie, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Thilo M Fuchs
- Zentralinstitut für Ernährungs- und Lebensmittelforschung (ZIEL), Abteilung Mikrobiologie, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany
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87
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Guo A, Lasaro MA, Sirard JC, Kraehenbühl JP, Schifferli DM. Adhesin-dependent binding and uptake of Salmonella enterica serovar Typhimurium by dendritic cells. MICROBIOLOGY-SGM 2007; 153:1059-1069. [PMID: 17379714 DOI: 10.1099/mic.0.2006/000331-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Salmonella enterica serovar Typhimurium can be internalized by immature dendritic cells (DCs). The interacting host and bacterial molecules initiating this process remain uncharacterized. The objective of this study was to investigate whether specific fimbriae are involved in the early step of binding and uptake of Salmonella by DCs. Type 1 fimbriated S. enterica serovar Typhimurium or recombinant Escherichia coli expressing the type 1 fimbriae showed a significantly greater ability to attach to murine bone-marrow-derived DCs than non-fimbriated bacteria. The FimH adhesin was required for efficient interactions with DCs, since fimbriated fimH mutants were impaired in both binding and internalization. Finally, the internalization involved a FimH-dependent process but did not require sipB, a gene essential for Salmonella-mediated invasion of mammalian epithelial cells. Collectively, these data suggest that the bacterial interaction of DCs through the type 1 fimbrial adhesin FimH is sufficient to target S. enterica serovar Typhimurium for cellular uptake.
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Affiliation(s)
- Aizhen Guo
- University of Pennsylvania School of Veterinary Medicine, 3800 Spruce Street, Philadelphia, PA 19104, USA
| | - Melissa A Lasaro
- University of Pennsylvania School of Veterinary Medicine, 3800 Spruce Street, Philadelphia, PA 19104, USA
| | - Jean-Claude Sirard
- Swiss Institute for Experimental Cancer Research (ISREC), 1066 Epalinges, Switzerland
| | | | - Dieter M Schifferli
- University of Pennsylvania School of Veterinary Medicine, 3800 Spruce Street, Philadelphia, PA 19104, USA
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88
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Glasner JD, Plunkett G, Anderson BD, Baumler DJ, Biehl BS, Burland V, Cabot EL, Darling AE, Mau B, Neeno-Eckwall EC, Pot D, Qiu Y, Rissman AI, Worzella S, Zaremba S, Fedorko J, Hampton T, Liss P, Rusch M, Shaker M, Shaull L, Shetty P, Thotakura S, Whitmore J, Blattner FR, Greene JM, Perna NT. Enteropathogen Resource Integration Center (ERIC): bioinformatics support for research on biodefense-relevant enterobacteria. Nucleic Acids Res 2007; 36:D519-23. [PMID: 17999997 PMCID: PMC2238966 DOI: 10.1093/nar/gkm973] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
ERIC, the Enteropathogen Resource Integration Center (www.ericbrc.org), is a new web portal serving as a rich source of information about enterobacteria on the NIAID established list of Select Agents related to biodefense—diarrheagenic Escherichia coli, Shigella spp., Salmonella spp., Yersinia enterocolitica and Yersinia pestis. More than 30 genomes have been completely sequenced, many more exist in draft form and additional projects are underway. These organisms are increasingly the focus of studies using high-throughput experimental technologies and computational approaches. This wealth of data provides unprecedented opportunities for understanding the workings of basic biological systems and discovery of novel targets for development of vaccines, diagnostics and therapeutics. ERIC brings information together from disparate sources and supports data comparison across different organisms, analysis of varying data types and visualization of analyses in human and computer-readable formats.
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Affiliation(s)
- Jeremy D Glasner
- Genome Center, University of Wisconsin, 425G Henry Mall, Madison, Madison, WI 53703, USA.
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89
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Hébert L, Courtin P, Torelli R, Sanguinetti M, Chapot-Chartier MP, Auffray Y, Benachour A. Enterococcus faecalis constitutes an unusual bacterial model in lysozyme resistance. Infect Immun 2007; 75:5390-8. [PMID: 17785473 PMCID: PMC2168276 DOI: 10.1128/iai.00571-07] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lysozyme is an important and widespread compound of the host constitutive defense system, and it is assumed that Enterococcus faecalis is one of the few bacteria that are almost completely lysozyme resistant. On the basis of the sequence analysis of the whole genome of E. faecalis V583 strain, we identified two genes that are potentially involved in lysozyme resistance, EF_0783 and EF_1843. Protein products of these two genes share significant homology with Staphylococcus aureus peptidoglycan O-acetyltransferase (OatA) and Streptococcus pneumoniae N-acetylglucosamine deacetylase (PgdA), respectively. In order to determine whether EF_0783 and EF_1843 are involved in lysozyme resistance, we constructed their corresponding mutants and a double mutant. The DeltaEF_0783 mutant and DeltaEF_0783 DeltaEF_1843 double mutant were shown to be more sensitive to lysozyme than the parental E. faecalis JH2-2 strain and DeltaEF_1843 mutant were. However, compared to other bacteria, such as Listeria monocytogenes or S. pneumoniae, the tolerance of DeltaEF_0783 and DeltaEF_0783 DeltaEF_1843 mutants towards lysozyme remains very high. Peptidoglycan structure analysis showed that EF_0783 modifies the peptidoglycan by O acetylation of N-acetyl muramic acid, while the EF_1843 deletion has no obvious effect on peptidoglycan structure under the same conditions. Moreover, the EF_0783 and EF_1843 deletions seem to significantly affect the ability of E. faecalis to survive within murine macrophages. In all, while EF_0783 is currently involved in the lysozyme resistance of E. faecalis, peptidoglycan O acetylation and de-N-acetylation are not the main mechanisms conferring high levels of lysozyme resistance to E. faecalis.
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Affiliation(s)
- Laurent Hébert
- Laboratoire de Microbiologie de l'Environnement, USC INRA 2017, EA956, Université de Caen, 14032 Caen Cedex, France
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90
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Oxygen restriction increases the infective potential of Listeria monocytogenes in vitro in Caco-2 cells and in vivo in guinea pigs. BMC Microbiol 2007; 7:55. [PMID: 17570840 PMCID: PMC1899506 DOI: 10.1186/1471-2180-7-55] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2006] [Accepted: 06/14/2007] [Indexed: 11/10/2022] Open
Abstract
Background Listeria monocytogenes has been implicated in several food borne outbreaks as well as sporadic cases of disease. Increased understanding of the biology of this organism is important in the prevention of food borne listeriosis. The infectivity of Listeria monocytogenes ScottA, cultivated with and without oxygen restriction, was compared in vitro and in vivo. Fluorescent protein labels were applied to allow certain identification of Listeria cells from untagged bacteria in in vivo samples, and to distinguish between cells grown under different conditions in mixed infection experiments. Results Infection of Caco-2 cells revealed that Listeria cultivated under oxygen-restricted conditions were approximately 100 fold more invasive than similar cultures grown without oxygen restriction. This was observed for exponentially growing bacteria, as well as for stationary-phase cultures. Oral dosage of guinea pigs with Listeria resulted in a significantly higher prevalence (p < 0.05) of these bacteria in jejunum, liver and spleen four and seven days after challenge, when the bacterial cultures had been grown under oxygen-restricted conditions prior to dosage. Additionally, a 10–100 fold higher concentration of Listeria in fecal samples was observed after dosage with oxygen-restricted bacteria. These differences were seen after challenge with single Listeria cultures, as well as with a mixture of two cultures grown with and without oxygen restriction. Conclusion Our results show for the first time that the environmental conditions to which L. monocytogenes is exposed prior to ingestion are decisive for its in vivo infective potential in the gastrointestinal tract after passage of the gastric barrier. This is highly relevant for safety assessment of this organism in food.
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91
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Webb-Robertson BJM, Peterson ES, Singhal M, Klicker KR, Oehmen CS, Adkins JN, Havre SL. PQuad—a visual analysis platform for proteomic data exploration of microbial organisms. Bioinformatics 2007; 23:1705-7. [PMID: 17483503 DOI: 10.1093/bioinformatics/btm132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
UNLABELLED The visual Platform for Proteomics Peptide and Protein data exploration (PQuad) is a multi-resolution environment that visually integrates genomic and proteomic data for prokaryotic systems, overlays categorical annotation and compares differential expression experiments. PQuad requires Java 1.5 and has been tested to run across different operating systems. AVAILABILITY http://ncrr.pnl.gov/software.
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92
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Manes NP, Gustin JK, Rue J, Mottaz HM, Purvine SO, Norbeck AD, Monroe ME, Zimmer JSD, Metz TO, Adkins JN, Smith RD, Heffron F. Targeted protein degradation by Salmonella under phagosome-mimicking culture conditions investigated using comparative peptidomics. Mol Cell Proteomics 2007; 6:717-27. [PMID: 17228056 DOI: 10.1074/mcp.m600282-mcp200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The pathogen Salmonella enterica is known to cause both food poisoning and typhoid fever. Because of the emergence of antibiotic-resistant isolates and the threat of bioterrorism (e.g. contamination of the food supply), there is a growing need to study this bacterium. In this investigation, comparative peptidomics was used to study S. enterica serovar Typhimurium cultured in either a rich medium or in an acidic, low magnesium, and minimal nutrient medium designed to roughly mimic the macrophage phagosomal environment (within which Salmonella are known to survive). Native peptides from cleared cell lysates were enriched by using isopropanol extraction and analyzed by using both LC-MS/MS and LC-FTICR-MS. We identified and quantified 5,163 peptides originating from 682 proteins, and the data clearly indicated that compared with Salmonella cultured in the rich medium, cells cultured in the phagosome-mimicking medium had dramatically higher abundances of a wide variety of protein degradation products, especially from ribosomal proteins. Salmonella from the same cultures were also analyzed using traditional, bottom-up proteomic methods, and when the peptidomics and proteomics data were analyzed together, two clusters of proteins targeted for proteolysis were tentatively identified. Possible roles of targeted proteolysis by phagocytosed Salmonella are discussed.
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Affiliation(s)
- Nathan P Manes
- Fundamental Science Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
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93
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Fink RC, Evans MR, Porwollik S, Vazquez-Torres A, Jones-Carson J, Troxell B, Libby SJ, McClelland M, Hassan HM. FNR is a global regulator of virulence and anaerobic metabolism in Salmonella enterica serovar Typhimurium (ATCC 14028s). J Bacteriol 2007; 189:2262-73. [PMID: 17220229 PMCID: PMC1899381 DOI: 10.1128/jb.00726-06] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Salmonella enterica serovar Typhimurium must successfully transition the broad fluctuations in oxygen concentrations encountered in the host. In Escherichia coli, FNR is one of the main regulatory proteins involved in O2 sensing. To assess the role of FNR in serovar Typhimurium, we constructed an isogenic fnr mutant in the virulent wild-type strain (ATCC 14028s) and compared their transcriptional profiles and pathogenicities in mice. Here, we report that, under anaerobic conditions, 311 genes (6.80% of the genome) are regulated directly or indirectly by FNR; of these, 87 genes (28%) are poorly characterized. Regulation by FNR in serovar Typhimurium is similar to, but distinct from, that in E. coli. Thus, genes/operons involved in aerobic metabolism, NO. detoxification, flagellar biosynthesis, motility, chemotaxis, and anaerobic carbon utilization are regulated by FNR in a fashion similar to that in E. coli. However, genes/operons existing in E. coli but regulated by FNR only in serovar Typhimurium include those coding for ethanolamine utilization, a universal stress protein, a ferritin-like protein, and a phosphotransacetylase. Interestingly, Salmonella-specific genes/operons regulated by FNR include numerous virulence genes within Salmonella pathogenicity island 1 (SPI-1), newly identified flagellar genes (mcpAC, cheV), and the virulence operon (srfABC). Furthermore, the role of FNR as a positive regulator of motility, flagellar biosynthesis, and pathogenesis was confirmed by showing that the mutant is nonmotile, lacks flagella, is attenuated in mice, and does not survive inside macrophages. The inability of the mutant to survive inside macrophages is likely due to its sensitivity to the reactive oxygen species generated by NADPH phagocyte oxidase.
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Affiliation(s)
- Ryan C Fink
- Department of Microbiology, North Carolina State University, Raleigh, NC 27695-7615, USA
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94
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Snelling WJ, Lin Q, Moore JE, Millar BC, Tosini F, Pozio E, Dooley JSG, Lowery CJ. Proteomics analysis and protein expression during sporozoite excystation of Cryptosporidium parvum (Coccidia, Apicomplexa). Mol Cell Proteomics 2006; 6:346-55. [PMID: 17124246 DOI: 10.1074/mcp.m600372-mcp200] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cryptosporidiosis, caused by coccidian parasites of the genus Cryptosporidium, is a major cause of human gastrointestinal infections and poses a significant health risk especially to immunocompromised patients. Despite intensive efforts for more than 20 years, there is currently no effective drug treatment against these protozoa. This study examined the zoonotic species Cryptosporidium parvum at two important stages of its life cycle: the non-excysted (transmissive) and excysted (infective) forms. To increase our understanding of the molecular basis of sporozoite excystation, LC-MS/MS coupling with a stable isotope N-terminal labeling strategy using iTRAQ reagents was used on soluble fractions of both non-excysted and excysted sporozoites, i.e. sporozoites both inside and outside oocysts were examined. Sporozoites are the infective stage that penetrates small intestinal enterocytes. Also to increase our knowledge of the C. parvum proteome, shotgun sequencing was performed on insoluble fractions from both non-excysted and excysted sporozoites. In total 303 C. parvum proteins were identified, 56 of which, hitherto described as being only hypothetical proteins, are expressed in both excysted and non-excysted sporozoites. Importantly we demonstrated that the expression of 26 proteins increases significantly during excystation. These excystation-induced proteins included ribosomal proteins, metabolic enzymes, and heat shock proteins. Interestingly three Apicomplexa-specific proteins and five Cryptosporidium-specific proteins augmented in excysted invasive sporozoites. These eight proteins represent promising targets for developing vaccines or chemotherapies that could block parasite entry into host cells.
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Affiliation(s)
- William J Snelling
- Centre for Molecular Biosciences, School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine, County Londonderry BT52 1SA, Northern Ireland
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95
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Jaitly N, Monroe ME, Petyuk VA, Clauss TRW, Adkins JN, Smith RD. Robust Algorithm for Alignment of Liquid Chromatography−Mass Spectrometry Analyses in an Accurate Mass and Time Tag Data Analysis Pipeline. Anal Chem 2006; 78:7397-409. [PMID: 17073405 DOI: 10.1021/ac052197p] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Liquid chromatography coupled to mass spectrometry (LC-MS) and tandem mass spectrometry (LC-MS/MS) has become a standard technique for analyzing complex peptide mixtures to determine composition and relative abundance. Several high-throughput proteomics techniques attempt to combine complementary results from multiple LC-MS and LC-MS/MS analyses to provide more comprehensive and accurate results. To effectively collate and use results from these techniques, variations in mass and elution time measurements between related analyses need to be corrected using algorithms designed to align the various types of data: LC-MS/MS versus LC-MS/MS, LC-MS versus LC-MS/MS, and LC-MS versus LC-MS. Described herein are new algorithms referred to collectively as liquid chromatography-based mass spectrometric warping and alignment of retention times of peptides (LCMSWARP), which use a dynamic elution time warping approach similar to traditional algorithms that correct for variations in LC elution times using piecewise linear functions. LCMSWARP is compared to the equivalent approach based upon linear transformation of elution times. LCMSWARP additionally corrects for temporal drift in mass measurement accuracies. We also describe the alignment of LC-MS results and demonstrate their application to the alignment of analyses from different chromatographic systems, showing the suitability of the present approach for more complex transformations.
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Affiliation(s)
- Navdeep Jaitly
- Environmental Molecular Science Laboratory and Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
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96
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Shi L, Adkins JN, Coleman JR, Schepmoes AA, Dohnkova A, Mottaz HM, Norbeck AD, Purvine SO, Manes NP, Smallwood HS, Wang H, Forbes J, Gros P, Uzzau S, Rodland KD, Heffron F, Smith RD, Squier TC. Proteomic analysis of Salmonella enterica serovar typhimurium isolated from RAW 264.7 macrophages: identification of a novel protein that contributes to the replication of serovar typhimurium inside macrophages. J Biol Chem 2006; 281:29131-40. [PMID: 16893888 DOI: 10.1074/jbc.m604640200] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To evade host resistance mechanisms, Salmonella enterica serovar Typhimurium (STM), a facultative intracellular pathogen, must alter its proteome following macrophage infection. To identify new colonization and virulence factors that mediate STM pathogenesis, we have isolated STM cells from RAW 264.7 macrophages at various time points following infection and used a liquid chromatography-mass spectrometry-based proteomic approach to detect the changes in STM protein abundance. Because host resistance to STM infection is strongly modulated by the expression of a functional host-resistant regulator, i.e. natural resistance-associated macrophage protein 1 (Nramp1, also called Slc11a1), we have also examined the effects of Nramp1 activity on the changes of STM protein abundances. A total of 315 STM proteins have been identified from isolated STM cells, which are largely housekeeping proteins whose abundances remain relatively constant during the time course of infection. However, 39 STM proteins are strongly induced after infection, suggesting their involvement in modulating colonization and infection. Of the 39 induced proteins, 6 proteins are specifically modulated by Nramp1 activity, including STM3117, as well as STM3118-3119 whose time-dependent abundance changes were confirmed using Western blot analysis. Deletion of the gene encoding STM3117 resulted in a dramatic reduction in the ability of STM to colonize wild-type RAW 264.7 macrophages, demonstrating a critical involvement of STM3117 in promoting the replication of STM inside macrophages. The predicted function common for STM3117-3119 is biosynthesis and modification of the peptidoglycan layer of the STM cell wall.
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Affiliation(s)
- Liang Shi
- Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
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