| trogocytosis-associated cell to cell spread of intracellular bacterial pathogens. | macrophages are myeloid-derived phagocytic cells and one of the first immune cell types to respond to microbial infections. however, a number of bacterial pathogens are resistant to the antimicrobial activities of macrophages and can grow within these cells. macrophages have other immune surveillance roles including the acquisition of cytosolic components from multiple types of cells. we hypothesized that intracellular pathogens that can replicate within macrophages could also exploit cytosolic ... | 2016 | 26802627 |
| caspase-1 activity is required to bypass macrophage apoptosis upon salmonella infection. | here we report awp28, an activity-based probe that can be used to biochemically monitor caspase-1 activation in response to proinflammatory stimuli. using awp28, we show that apoptosis is triggered upon salmonella enterica var. typhimurium infection in primary mouse bone marrow macrophages lacking caspase-1. furthermore, we report that upon salmonella infection, inflammasome-mediated caspase-1 activity is required to bypass apoptosis in favor of proinflammatory pyroptotic cell death. | 2012 | 22797665 |
| salmonella suppresses the trif-dependent type i interferon response in macrophages. | salmonella enterica is an intracellular pathogen that causes diseases ranging from gastroenteritis to typhoid fever. salmonella bacteria trigger an autophagic response in host cells upon infection but have evolved mechanisms for suppressing this response, thereby enhancing intracellular survival. we recently reported that s. enterica serovar typhimurium actively recruits the host tyrosine kinase focal adhesion kinase (fak) to the surface of the salmonella-containing vacuole (scv) (k. a. owen et ... | 2016 | 26884434 |
| novel highly thermostable endolysin from thermus scotoductus mat2119 bacteriophage ph2119 with amino acid sequence similarity to eukaryotic peptidoglycan recognition proteins. | in this study, we present the discovery and characterization of a highly thermostable endolysin from bacteriophage ph2119 infecting thermus strain mat2119 isolated from geothermal areas in iceland. nucleotide sequence analysis of the 16s rrna gene affiliated the strain with the species thermus scotoductus. bioinformatics analysis has allowed identification in the genome of phage 2119 of an open reading frame (468 bp in length) coding for a 155-amino-acid basic protein with an mr of 17,555. ph211 ... | 2014 | 24271162 |
| common evolutionary origin for the rotor domain of rotary atpases and flagellar protein export apparatus. | the v1- and f1- rotary atpases contain a rotor that rotates against a catalytic a3b3 or α3β3 stator. the rotor f(1-γ) or v1-df is composed of both anti-parallel coiled coil and globular-loop parts. the bacterial flagellar type iii export apparatus contains a v1/f1-like atpase ring structure composed of flii6 homo-hexamer and flij which adopts an anti-parallel coiled coil structure without the globular-loop part. here we report that flij of salmonella enterica serovar typhimurium shows a rotor li ... | 2013 | 23724081 |
| acetyl coenzyme a synthetase is acetylated on multiple lysine residues by a protein acetyltransferase with a single gcn5-type n-acetyltransferase (gnat) domain in saccharopolyspora erythraea. | reversible lysine acetylation (rla) is used by cells of all domains of life to modulate protein function. to date, bacterial acetylation/deacetylation systems have been studied in a few bacteria (e.g., salmonella enterica, bacillus subtilis, escherichia coli, erwinia amylovora, mycobacterium tuberculosis, and geobacillus kaustophilus), but little is known about rla in antibiotic-producing actinomycetes. here, we identify the gcn5-like protein acetyltransferase acua of saccharopolyspora erythraea ... | 2014 | 24957627 |
| molecular characterization of the na+/h+-antiporter nhaa from salmonella typhimurium. | na+/h+ antiporters are integral membrane proteins that are present in almost every cell and in every kingdom of life. they are essential for the regulation of intracellular ph-value, na+-concentration and cell volume. these secondary active transporters exchange sodium ions against protons via an alternating access mechanism, which is not understood in full detail. na+/h+ antiporters show distinct species-specific transport characteristics and regulatory properties that correlate with respective ... | 2014 | 25010413 |
| identification of essential genes in the salmonella phage spn3us reveals novel insights into giant phage head structure and assembly. | giant tailed bacterial viruses, or phages, such as pseudomonas aeruginosa phage ϕkz, have long genomes packaged into large, atypical virions. many aspects of ϕkz and related phage biology are poorly understood, mostly due to the fact that the functions of the majority of their proteins are unknown. we hypothesized that the salmonella enterica phage spn3us could be a useful model phage to address this gap in knowledge. the 240-kb spn3us genome shares a core set of 91 genes with ϕkz and related ph ... | 2016 | 27605673 |
| extreme antimicrobial peptide and polymyxin b resistance in the genus burkholderia. | cationic antimicrobial peptides and polymyxins are a group of naturally occurring antibiotics that can also possess immunomodulatory activities. they are considered a new source of antibiotics for treating infections by bacteria that are resistant to conventional antibiotics. members of the genus burkholderia, which includes various human pathogens, are inherently resistant to antimicrobial peptides. the resistance is several orders of magnitude higher than that of other gram-negative bacteria s ... | 2011 | 22919572 |
| variable carbon catabolism among salmonella enterica serovar typhi isolates. | salmonella enterica serovar typhi (s. typhi) is strictly a human intracellular pathogen. it causes acute systemic (typhoid fever) and chronic infections that result in long-term asymptomatic human carriage. s. typhi displays diverse disease manifestations in human infection and exhibits high clonality. the principal factors underlying the unique lifestyle of s. typhi in its human host during acute and chronic infections remain largely unknown and are therefore the main objective of this study. | 2012 | 22662115 |
| characterization of modular bacteriophage endolysins from myoviridae phages obp, 201φ2-1 and pvp-se1. | peptidoglycan lytic enzymes (endolysins) induce bacterial host cell lysis in the late phase of the lytic bacteriophage replication cycle. endolysins obpgp279 (from pseudomonas fluorescens phage obp), pvp-se1gp146 (salmonella enterica serovar enteritidis phage pvp-se1) and 201φ2-1gp229 (pseudomonas chlororaphis phage 201φ2-1) all possess a modular structure with an n-terminal cell wall binding domain and a c-terminal catalytic domain, a unique property for endolysins with a gram-negative backgrou ... | 2012 | 22615864 |
| impact of plasmids, including those encodingvirb4/d4 type iv secretion systems, on salmonella enterica serovar heidelberg virulence in macrophages and epithelial cells. | salmonella enterica serovar heidelberg (s. heidelberg) can cause foodborne illness in humans following the consumption of contaminated meat and poultry products. recent studies from our laboratory have demonstrated that certain s. heidelberg isolated from food-animal sources harbor multiple transmissible plasmids with genes that encode antimicrobial resistance, virulence and a virb4/d4 type-iv secretion system. this study examines the potential role of these transmissible plasmids in bacterial u ... | 2013 | 24098597 |
| evaluation of a simple blood culture amplification and antigen detection method for diagnosis of salmonella enterica serovar typhi bacteremia. | in most areas where typhoid is endemic, laboratory diagnosis is not possible due to the lack of appropriate facilities. we investigated whether the combination of blood culture amplification of salmonella enterica serovar typhi with an s. typhi antigen rapid diagnostic test (rdt) could be an accurate and inexpensive tool for the accelerated diagnosis of patients with acute typhoid in laos. for a panel of 23 gram-negative reference pathogens, the standard diagnostics (catalog no. 15fk20; kyonggi- ... | 2013 | 23100346 |
| arabidopsis and maize rida proteins preempt reactive enamine/imine damage to branched-chain amino acid biosynthesis in plastids. | rida (for reactive intermediate deaminase a) proteins are ubiquitous, yet their function in eukaryotes is unclear. it is known that deleting salmonella enterica rida causes ser sensitivity and that s. enterica rida and its homologs from other organisms hydrolyze the enamine/imine intermediates that thr dehydratase forms from ser or thr. in s. enterica, the ser-derived enamine/imine inactivates a branched-chain aminotransferase; rida prevents this damage. arabidopsis thaliana and maize (zea mays) ... | 2014 | 25070638 |
| the diagnostic accuracy of three rapid diagnostic tests for typhoid fever at chittagong medical college hospital, chittagong, bangladesh. | to determine the diagnostic accuracy of three rapid diagnostic tests (rdts) for typhoid fever in febrile hospitalised patients in bangladesh. | 2015 | 26094960 |
| development of a protocol for predicting bacterial resistance to microbicides. | regulations dealing with microbicides in europe and the united states are evolving and now require data on the risk of the development of resistance in organisms targeted by microbicidal products. there is no standard protocol to assess the risk of the development of resistance to microbicidal formulations. this study aimed to validate the use of changes in microbicide and antibiotic susceptibility as initial markers for predicting microbicide resistance and cross-resistance to antibiotics. thre ... | 2015 | 25636848 |
| modulation of the substitution pattern of 5-aryl-2-aminoimidazoles allows fine-tuning of their antibiofilm activity spectrum and toxicity. | we previously synthesized several series of compounds, based on the 5-aryl-2-aminoimidazole scaffold, that showed activity preventing the formation of salmonella enterica serovar typhimurium and pseudomonas aeruginosa biofilms. here, we further studied the activity spectrum of a number of the most active n1- and 2n-substituted 5-aryl-2-aminoimidazoles against a broad panel of biofilms formed by monospecies and mixed species of bacteria and fungi. an n1-substituted compound showed very strong act ... | 2016 | 27550355 |
| exploring the diversity and antimicrobial potential of marine actinobacteria from the comau fjord in northern patagonia, chile. | bioprospecting natural products in marine bacteria from fjord environments are attractive due to their unique geographical features. although, actinobacteria are well known for producing a myriad of bioactive compounds, investigations regarding fjord-derived marine actinobacteria are scarce. in this study, the diversity and biotechnological potential of actinobacteria isolated from marine sediments within the comau fjord, in northern chilean patagonia, were assessed by culture-based approaches. ... | 2016 | 27486455 |
| enhanced inactivation of salmonella and pseudomonas biofilms on stainless steel by use of t-128, a fresh-produce washing aid, in chlorinated wash solutions. | the effect of the washing aid t-128 (generally recognized as safe [gras] formulation, composed mainly of phosphoric acid and propylene glycol) on inactivation of salmonella and pseudomonas populations in biofilms on stainless steel was evaluated under conditions of increasing organic matter loads in chlorinated wash solutions dominated by hypochlorous acid. biofilms were formed statically on stainless steel coupons suspended in 2% lettuce extract after inoculation with salmonella enterica serova ... | 2012 | 22752180 |
| phosphorothioate dna as an antioxidant in bacteria. | diverse bacteria contain dna with sulfur incorporated stereo-specifically into their dna backbone at specific sequences (phosphorothioation). we found that in vitro oxidation of phosphorothioate (pt) dna by hydrogen peroxide (h(2)o(2)) or peracetic acid has two possible outcomes: dna backbone cleavage or sulfur removal resulting in restoration of normal dna backbone. the physiological relevance of this redox reaction was investigated by challenging pt dna hosting salmonella enterica cells using ... | 2012 | 22772986 |
| requirement of siderophore biosynthesis for plant colonization by salmonella enterica. | contaminated fresh produce has become the number one vector of nontyphoidal salmonellosis to humans. however, salmonella enterica genes essential for the life cycle of the organism outside the mammalian host are for the most part unknown. screening deletion mutants led to the discovery that an aroa mutant had a significant root colonization defect due to a failure to replicate. aroa is part of the chorismic acid biosynthesis pathway, a central metabolic node involved in aromatic amino acid and s ... | 2012 | 22522683 |
| phylogenomic analysis identifies gene gains that define salmonella enterica subspecies i. | comparative methods for analyzing whole genome sequence (wgs) data enable us to assess the genetic information available for reconstructing the evolutionary history of pathogens. we used the comparative approach to determine diagnostic genes for salmonella enterica subspecies i. s. enterica subsp. i strains are known to infect warm-blooded organisms regularly while its close relatives tend to infect only cold-blooded organisms. we found 71 genes gained by the common ancestor of salmonella enteri ... | 2013 | 24204679 |
| salmonella utilizes d-glucosaminate via a mannose family phosphotransferase system permease and associated enzymes. | salmonella enterica is a globally significant bacterial food-borne pathogen that utilizes a variety of carbon sources. we report here that salmonella enterica subsp. enterica serovar typhimurium (s. typhimurium) uses d-glucosaminate (2-amino-2-deoxy-d-gluconic acid) as a carbon and nitrogen source via a previously uncharacterized mannose family phosphotransferase system (pts) permease, and we designate the genes encoding the permease dgaabcd (d-glucosaminate pts permease components eiia, eiib, e ... | 2013 | 23836865 |
| epithelial cells augment barrier function via activation of the toll-like receptor 2/phosphatidylinositol 3-kinase pathway upon recognition of salmonella enterica serovar typhimurium curli fibrils in the gut. | curli fibrils, the best-characterized functional bacterial amyloids, are an important component of enterobacterial biofilms. we have previously shown that curli fibrils are recognized by the toll-like receptor 2 (tlr2)/tlr1 heterodimer complex. utilizing polarized t-84 cells, an intestinal epithelial cell line derived from colon carcinoma grown on semipermeable tissue culture inserts, we determined that infection with a salmonella enterica serovar typhimurium csgba mutant, which does not express ... | 2013 | 23208603 |
| the salmonella transcriptome in lettuce and cilantro soft rot reveals a niche overlap with the animal host intestine. | fresh vegetables have been recurrently associated with salmonellosis outbreaks, and salmonella contamination of retail produce has been correlated positively with the presence of soft rot disease. we observed that population sizes of salmonella enterica serovar typhimurium sl1344 increased 56-fold when inoculated alone onto cilantro leaves, versus 2,884-fold when coinoculated with dickeya dadantii, a prevalent pathogen that macerates plant tissue. a similar trend in s. enterica populations was o ... | 2013 | 23104408 |
| oregano essential oil-pectin edible films as anti-quorum sensing and food antimicrobial agents. | edible films can be used as carriers for antimicrobial compounds to assure food safety and quality; in addition, pathogenesis of food bacteria is related to a cell to cell communication mechanism called quorum sensing (qs). oregano essential oil (oeo) has proved to be useful as food antimicrobial; however, its food applications can be compromised by the volatile character of its active constituents. therefore, formulation of edible films containing oeo can be an alternative to improve its food u ... | 2014 | 25566215 |
| the cyclic antibacterial peptide enterocin as-48: isolation, mode of action, and possible food applications. | enterocin as-48 is a circular bacteriocin produced by enterococcus. it contains a 70 amino acid-residue chain circularized by a head-to-tail peptide bond. the conformation of enterocin as-48 is arranged into five alpha-helices with a compact globular structure. enterocin as-48 has a wide inhibitory spectrum on gram-positive bacteria. sensitivity of gram-negative bacteria increases in combination with outer-membrane permeabilizing treatments. eukaryotic cells are bacteriocin-resistant. this catio ... | 2014 | 25493478 |
| biofilm formation by enteric pathogens and its role in plant colonization and persistence. | the significant increase in foodborne outbreaks caused by contaminated fresh produce, such as alfalfa sprouts, lettuce, melons, tomatoes and spinach, during the last 30 years stimulated investigation of the mechanisms of persistence of human pathogens on plants. emerging evidence suggests that salmonella enterica and escherichia coli, which cause the vast majority of fresh produce outbreaks, are able to adhere to and to form biofilms on plants leading to persistence and resistance to disinfectio ... | 2014 | 25351039 |
| dna phosphorothioate modifications influence the global transcriptional response and protect dna from double-stranded breaks. | the modification of dna by phosphorothioate (pt) occurs when the non-bridging oxygen in the sugar-phosphate backbone of dna is replaced with sulfur. this dna backbone modification was recently discovered and is governed by the dndabcde genes in a diverse group of bacteria and archaea. however, the biological function of dna pt modifications is poorly understood. in this study, we employed the rna-seq analysis to characterize the global transcriptional changes in response to pt modifications. our ... | 2014 | 25319634 |
| evaluation of protective efficacy of live attenuated salmonella enterica serovar gallinarum vaccine strains against fowl typhoid in chickens. | salmonella enterica serovar gallinarum is the etiological agent of fowl typhoid, which constitutes a considerable economic problem for poultry growers in developing countries. the vaccination of chickens seems to be the most effective strategy to control the disease in those areas. we constructed s. gallinarum strains with a deletion of the global regulatory gene fur and evaluated their virulence and protective efficacy in rhode island red chicks and brown leghorn layers. the fur deletion mutant ... | 2014 | 24990908 |
| pathological phenotypes and in vivo dna cleavage by unrestrained activity of a phosphorothioate-based restriction system in salmonella. | prokaryotes protect their genomes from foreign dna with a diversity of defence mechanisms, including a widespread restriction-modification (r-m) system involving phosphorothioate (pt) modification of the dna backbone. unlike classical r-m systems, highly partial pt modification of consensus motifs in bacterial genomes suggests an unusual mechanism of pt-dependent restriction. in salmonella enterica, pt modification is mediated by four genes dptb-e, while restriction involves additional three gen ... | 2014 | 25040300 |
| in silico identification and experimental characterization of regulatory elements controlling the expression of the salmonella csrb and csrc genes. | the small rnas csrb and csrc of salmonella indirectly control the expression of numerous genes encoding widespread cellular functions, including virulence. the expression of csrb and csrc genes, which are located in different chromosomal regions, is coordinated by positive transcriptional control mediated by the two-component regulatory system bara/sira. here, we identified by computational analysis an 18-bp inverted repeat (ir) sequence located far upstream from the promoter of salmonella enter ... | 2014 | 24187088 |
| genomic targets and features of bara-uvry (-sira) signal transduction systems. | the two-component signal transduction system bara-uvry of escherichia coli and its orthologs globally regulate metabolism, motility, biofilm formation, stress resistance, virulence of pathogens and quorum sensing by activating the transcription of genes for regulatory srnas, e.g. csrb and csrc in e. coli. these srnas act by sequestering the rna binding protein csra (rsma) away from lower affinity mrna targets. in this study, we used chip-exo to identify, at single nucleotide resolution, genomic ... | 2015 | 26673755 |
| regulation of dna phosphorothioate modification in salmonella enterica by dndb. | dna phosphorothioate (pt) modification, in which the non-bridging oxygen of the sugar-phosphate backbone is substituted by sulfur, occurs naturally in diverse bacteria and archaea and is regulated by the dndabcde proteins. dndabcde and the restriction cognate dndfghi constitute a new type of defense system that prevents the invasion of foreign dna in salmonella enterica serovar cerro 87. gaac/gttc consensus contexts across genomes were found to possess partial pt modifications even in the presen ... | 2015 | 26190504 |
| inhibition of pathogenic and spoilage bacteria by a novel biofilm-forming lactobacillus isolate: a potential host for the expression of heterologous proteins. | bacterial biofilms are a preferred mode of growth for many types of microorganisms in their natural environments. the ability of pathogens to integrate within a biofilm is pivotal to their survival. the possibility of biofilm formation in lactobacillus communities is also important in various industrial and medical settings. lactobacilli can eliminate the colonization of different pathogenic microorganisms. alternatively, new opportunities are now arising with the rapidly expanding potential of ... | 2015 | 26150120 |
| de novo amino acid biosynthesis contributes to salmonella enterica growth in alfalfa seedling exudates. | salmonella enterica is a member of the plant microbiome. growth of s. enterica in sprouting-seed exudates is rapid; however, the active metabolic networks essential in this environment are unknown. to examine the metabolic requirements of s. enterica during growth in sprouting-seed exudates, we inoculated alfalfa seeds and identified 305 s. enterica proteins extracted 24 h postinoculation from planktonic cells. over half the proteins had known metabolic functions, and they are involved in over o ... | 2015 | 25416761 |
| metagenomic analysis of medicinal cannabis samples; pathogenic bacteria, toxigenic fungi, and beneficial microbes grow in culture-based yeast and mold tests. | background: the presence of bacteria and fungi in medicinal or recreational cannabis poses a potential threat to consumers if those microbes include pathogenic or toxigenic species. this study evaluated two widely used culture-based platforms for total yeast and mold (tym) testing marketed by 3m corporation and biomérieux, in comparison with a quantitative pcr (qpcr) approach marketed by medicinal genomics corporation. methods: a set of 15 medicinal cannabis samples were analyzed using 3m and bi ... | 2016 | 27853518 |
| environmental metabolomics of the tomato plant surface provides insights on salmonella enterica colonization. | foodborne illness-causing enteric bacteria are able to colonize plant surfaces without causing infection. we lack an understanding of how epiphytic persistence of enteric bacteria occurs on plants, possibly as an adaptive transit strategy to maximize chances of reentering herbivorous hosts. we used tomato (solanum lycopersicum) cultivars that have exhibited differential susceptibilities to salmonella enterica colonization to investigate the influence of plant surface compounds and exudates on en ... | 2016 | 26994076 |
| use of metagenomic shotgun sequencing technology to detect foodborne pathogens within the microbiome of the beef production chain. | foodborne illnesses associated with pathogenic bacteria are a global public health and economic challenge. the diversity of microorganisms (pathogenic and nonpathogenic) that exists within the food and meat industries complicates efforts to understand pathogen ecology. further, little is known about the interaction of pathogens within the microbiome throughout the meat production chain. here, a metagenomic approach and shotgun sequencing technology were used as tools to detect pathogenic bacteri ... | 2016 | 26873315 |
| differential biofilm formation and chemical disinfection resistance of sessile cells of listeria monocytogenes strains under monospecies and dual-species (with salmonella enterica) conditions. | this study aimed to investigate the possible influence of bacterial intra- and interspecies interactions on the ability of listeria monocytogenes and salmonella enterica to develop mixed-culture biofilms on an abiotic substratum, as well as on the subsequent resistance of sessile cells to chemical disinfection. initially, three strains from each species were selected and left to attach and form biofilms on stainless steel (ss) coupons incubated at 15°c for 144 h, in periodically renewable trypto ... | 2012 | 22307304 |
| intra- and inter-species interactions within biofilms of important foodborne bacterial pathogens. | a community-based sessile life style is the normal mode of growth and survival for many bacterial species. under such conditions, cell-to-cell interactions are inevitable and ultimately lead to the establishment of dense, complex and highly structured biofilm populations encapsulated in a self-produced extracellular matrix and capable of coordinated and collective behavior. remarkably, in food processing environments, a variety of different bacteria may attach to surfaces, survive, grow, and for ... | 2015 | 26347727 |
| isolation and preliminary characterization of amino acid substitution mutations that increase the activity of the osmoregulated prop protein of salmonella enterica serovar typhimurium. | in enterobacteriaceae, the prop protein, which takes up proline and glycine betaine, is subject to a post-translational control mechanism that increases its activity at high osmolarity. in order to investigate the osmoregulatory mechanism of the salmonella enterica prop, we devised a positive selection for mutations that conferred increased activity on this protein at low osmolarity. the selection involved the isolation of mutations in a proline auxotroph that resulted in increased accumulation ... | 2012 | 22360681 |
| isolation of a paenibacillus sp. strain and structural elucidation of its broad-spectrum lipopeptide antibiotic. | this research was initiated to search for novel antimicrobial compounds produced by food or environmental microorganisms. a new bacterial strain, designated osy-se, which produces a unique and potent antimicrobial agent was isolated from soil. the isolate was identified as a paenibacillus sp. through cultural, biochemical, and genetic analyses. an antimicrobial compound was extracted from paenibacillus osy-se with acetonitrile and purified using liquid chromatography. after analyses by mass spec ... | 2012 | 22367082 |
| loss of culturability of salmonella enterica subsp. enterica serovar typhimurium upon cell-cell contact with human fecal bacteria. | loss of culturability of salmonella enterica subsp. enterica serovar typhimurium has been observed in mixed cultures with anaerobic fecal bacteria under conditions that allow local interaction between cells, such as cell contact. a reduction of a population of culturable s. typhimurium on the order of ∼10(4) to 10(5) cfu/ml was observed in batch anaerobic mixed cultures with fecal samples from different human donors. culturability was not affected either in supernatants collected at several time ... | 2013 | 23503308 |
| study on the promotion of bacterial biofilm formation by a salmonella conjugative plasmid and the underlying mechanism. | to investigate the effect of the prst98 plasmid, originally isolated from salmonella enterica serovar typhi (s. typhi), on biofilm (bf) formation, we carried out in vitro experiments using s. typhi, salmonella enterica serovar typhimurium (s. typhimurium) and escherichia coli (e. coli). we further explored the effects of prst98 in vivo by establishing two animal models, a tumor-bearing mouse model and a mouse urethral catheter model. moreover, we examined the relationship between the quorum-sens ... | 2014 | 25299072 |
| modulation of biofilm-formation in salmonella enterica serovar typhimurium by the periplasmic dsba/dsbb oxidoreductase system requires the ggdef-eal domain protein stm3615. | in salmonella enterica serovar typhimurium (s. typhimurium), biofilm-formation is controlled by the cytoplasmic intracellular small-molecular second messenger cyclic 3', 5'-di- guanosine monophosphate (c-di-gmp) through the activities of ggdef and eal domain proteins. here we describe that deleting either dsba or dsbb, respectively encoding a periplasmic protein disulfide oxidase and a cytoplasmic membrane disulfide oxidoreductase, resulted in increased biofilm-formation on solid medium. this in ... | 2014 | 25153529 |
| the salmonella enterica serovar typhi leuo global regulator forms tetramers: residues involved in oligomerization, dna binding, and transcriptional regulation. | leuo is a lysr-type transcriptional regulator (lttr) that has been described to be a global regulator in escherichia coli and salmonella enterica, since it positively and negatively regulates the expression of genes involved in multiple biological processes. leuo is comprised of an n-terminal dna-binding domain (dbd) with a winged helix-turn-helix (whth) motif and of a long linker helix (lh) involved in dimerization that connects the dbd with the c-terminal effector-binding domain (ebd) or regul ... | 2014 | 24659766 |
| a macrophage subversion factor is shared by intracellular and extracellular pathogens. | pathogenic bacteria have developed strategies to adapt to host environment and resist host immune response. several intracellular bacterial pathogens, including salmonella enterica and mycobacterium tuberculosis, share the horizontally-acquired mgtc virulence factor that is important for multiplication inside macrophages. mgtc is also found in pathogenic pseudomonas species. here we investigate for the first time the role of mgtc in the virulence of an extracellular pathogen, pseudomonas aerugin ... | 2015 | 26080006 |
| conjunctival flora of clinically normal and diseased turtles and tortoises. | in captive breed turtles and tortoises conjunctival disease is common. our aim was to investigate the bacterial and fungal flora present in the eyes of healthy and pathological chelonians and to compare findings in turtles with those in tortoises. | 2015 | 25889261 |
| srfj, a salmonella type iii secretion system effector regulated by phop, rcsb, and iolr. | virulence-related type iii secretion systems are present in many gram-negative bacterial pathogens. these complex devices translocate proteins, called effectors, from the bacterium into the eukaryotic host cell. here, we identify the product of srfj, a salmonella enterica serovar typhimurium gene regulated by ssrb, as a new substrate of the type iii secretion system encoded by salmonella pathogenicity island 2. the n-terminal 20-amino-acid segment of srfj was recognized as a functional secretion ... | 2012 | 22661691 |
| functional and computational analysis of amino acid patterns predictive of type iii secretion system substrates in pseudomonas syringae. | bacterial type iii secretion systems (t3sss) deliver proteins called effectors into eukaryotic cells. although n-terminal amino acid sequences are required for translocation, the mechanism of substrate recognition by the t3ss is unknown. almost all actively deployed t3ss substrates in the plant pathogen pseudomonas syringae pathovar tomato strain dc3000 possess characteristic patterns, including (i) greater than 10% serine within the first 50 amino acids, (ii) an aliphatic residue or proline at ... | 2012 | 22558318 |
| cytosporone b, an inhibitor of the type iii secretion system of salmonella enterica serovar typhimurium. | bacterial virulence factors have been increasingly regarded as attractive targets for development of novel antibacterial agents. virulence inhibitors are less likely to generate bacterial resistance, which makes them superior to traditional antibiotics that target bacterial viability. salmonella enterica serovar typhimurium, an important food-borne human pathogen, has type iii secretion system (t3ss) as its major virulence factor. t3ss secretes effector proteins to facilitate invasion into host ... | 2013 | 23459474 |
| molecular diagnostics in a teacup: non-instrumented nucleic acid amplification (nina) for rapid, low cost detection of salmonella enterica. | we report on the use of a novel non-instrumented platform to enable a loop mediated isothermal amplification (lamp) based assay for salmonella enterica. heat energy is provided by addition of a small amount (<150 g) of boiling water, and the reaction temperature is regulated by storing latent energy at the melting temperature of a lipid-based engineered phase change material. endpoint classification of the reaction is achieved without opening the reaction tube by observing the fluorescence of se ... | 2013 | 25477717 |
| active modification of host inflammation by salmonella. | the dampening of host immune responses is a critical aspect of pathogenesis for the enteropathogen salmonella enterica. our laboratory has recently described a role for the secreted effector gogb in disruption of nfκb activation and limitation of the host inflammatory response to infection. gogb alters the nfκb pathway by preventing iκb degradation by the host scf e3 ubiquitin ligase, through an interaction with skp1 and fbxo22. the prevention of nfκb activation through this interaction dampens ... | 2013 | 23333857 |
| in situ evaluation of paenibacillus alvei in reducing carriage of salmonella enterica serovar newport on whole tomato plants. | recently, tomatoes have been implicated as a primary vehicle in food-borne outbreaks of salmonella enterica serovar newport and other salmonella serovars. long-term intervention measures to reduce salmonella prevalence on tomatoes remain elusive for growing and postharvest environments. a naturally occurring bacterium identified by 16s rrna gene sequencing as paenibacillus alvei was isolated epiphytically from plants native to the virginia eastern shore tomato-growing region. after initial antim ... | 2014 | 24747888 |
| phylogenetic and amino acid conservation analyses of bacterial l-aspartate-α-decarboxylase and of its zymogen-maturation protein reveal a putative interaction domain. | all organisms must synthesize the enzymatic cofactor coenzyme a (coa) from the precursor pantothenate. most bacteria can synthesize pantothenate de novo by the condensation of pantoate and β-alanine. the synthesis of β-alanine is catalyzed by l-aspartate-α-decarboxylase (pand), a pyruvoyl enzyme that is initially synthesized as a zymogen (pro-pand). active pand is generated by self-cleavage of pro-pand at gly24-ser25 creating the active-site pyruvoyl moiety. in salmonella enterica, this cleavage ... | 2015 | 26276430 |
| real-time duplex applications of loop-mediated amplification (lamp) by assimilating probes. | isothermal nucleic-acid amplification methods such as loop-mediated isothermal amplification (lamp) are increasingly appealing alternatives to pcr for use in portable diagnostic system due to the low cost, weight, and power requirements of the instrumentation. as such, interest in developing new probes and other functionality based on the lamp reaction has been intense. here, we report on the development of duplexed lamp assays for pathogen detection using spectrally unique assimilating probes. ... | 2015 | 25741765 |
| engineering of acetyl-coa metabolism for the improved production of polyhydroxybutyrate in saccharomyces cerevisiae. | through metabolic engineering microorganisms can be engineered to produce new products and further produce these with higher yield and productivities. here, we expressed the bacterial polyhydroxybutyrate (phb) pathway in the yeast saccharomyces cerevisiae and we further evaluated the effect of engineering the formation of acetyl coenzyme a (acetyl-coa), an intermediate of the central carbon metabolism and precursor of the phb pathway, on heterologous phb production by yeast. we engineered the ac ... | 2012 | 23009357 |
| rna sequencing reveals differences between the global transcriptomes of salmonella enterica serovar enteritidis strains with high and low pathogenicities. | salmonella enterica serovar enteritidis is one of the important causes of bacterial food-borne gastroenteritis worldwide. field strains of s. enteritidis are relatively genetically homogeneous; however, they show extensive phenotypic diversity and differences in virulence potential. rna sequencing (rna-seq) was used to characterize differences in the global transcriptome between several genetically similar but phenotypically diverse poultry-associated field strains of s. enteritidis grown in lab ... | 2014 | 24271167 |
| cadmium resistance and uptake by bacterium, salmonella enterica 43c, isolated from industrial effluent. | cadmium resistant bacterium, isolated from industrial wastewater, was characterized as salmonella enterica 43c on the basis of biochemical and 16s rrna ribotyping. it is first ever reported s. enterica 43c bared extreme resistance against heavy metal consortia in order of pb(2+)>cd(2+)>as(3+)>zn(2+)>cr(6+)>cu(2+)>hg(2+). cd(2+) stress altered growth pattern of the bacterium in time dependent manner. it could remove nearly 57 % cd(2+) from the medium over a period of 8 days. kinetic and thermodyn ... | 2016 | 27491862 |
| type vi secretion system-associated gene clusters contribute to pathogenesis of salmonella enterica serovar typhimurium. | the enteropathogen salmonella enterica serovar typhimurium employs a suite of tightly regulated virulence factors within the intracellular compartment of phagocytic host cells resulting in systemic dissemination in mice. a type vi secretion system (t6ss) within salmonella pathogenicity island 6 (spi-6) has been implicated in this process; however, the regulatory inputs and the roles of noncore genes in this system are not well understood. here we describe four clusters of noncore t6ss genes in s ... | 2012 | 22493086 |
| a glycine betaine importer limits salmonella stress resistance and tissue colonization by reducing trehalose production. | mechanisms by which salmonella establish chronic infections are not well understood. microbes respond to stress by importing or producing compatible solutes, small molecules that stabilize proteins and lipids. the salmonella locus opuabcd (also called opuc) encodes a predicted importer of the compatible solute glycine betaine. under stress conditions, if glycine betaine cannot be imported, salmonella enterica produce the disaccharide trehalose, a highly effective compatible solute. we demonstrat ... | 2012 | 22375627 |
| allelic variation in salmonella: an underappreciated driver of adaptation and virulence. | salmonella enterica causes substantial morbidity and mortality in humans and animals. infection and intestinal colonization by s. enterica require virulence factors that mediate bacterial binding and invasion of enterocytes and innate immune cells. some s. enterica colonization factors and their alleles are host restricted, suggesting a potential role in regulation of host specificity. recent data also suggest that colonization factors promote horizontal gene transfer of antimicrobial resistance ... | 2013 | 24454310 |
| escherichia coli o157:h7 induces stronger plant immunity than salmonella enterica typhimurium sl1344. | consumption of fresh produce contaminated with bacterial human pathogens has resulted in various, sometimes deadly, disease outbreaks. in this study, we assessed plant defense responses induced by the fully pathogenic bacteria escherichia coli o157:h7 and salmonella enterica serovar typhimurium sl1344 in both arabidopsis thaliana and lettuce (lactuca sativa). unlike sl1344, o157:h7 induced strong plant immunity at both pre-invasion and post-invasion steps of infection. for instance, o157:h7 trig ... | 2013 | 23301812 |
| interactions of salmonella with animals and plants. | salmonella enterica species are gram-negative bacteria, which are responsible for a wide range of food- and water-borne diseases in both humans and animals, thereby posing a major threat to public health. recently, there has been an increasing number of reports, linking salmonella contaminated raw vegetables and fruits with food poisoning. many studies have shown that an essential feature of the pathogenicity of salmonella is its capacity to cross a number of barriers requiring invasion of a lar ... | 2014 | 25653644 |
| effect of the surfactant tween 80 on the detachment and dispersal of salmonella enterica serovar thompson single cells and aggregates from cilantro leaves as revealed by image analysis. | salmonella enterica has the ability to form biofilms and large aggregates on produce surfaces, including on cilantro leaves. aggregates of s. enterica serovar thompson that remained attached to cilantro leaves after rigorous washing and that were present free or bound to dislodged leaf tissue in the wash suspension were observed by confocal microscopy. measurement of s. thompson population sizes in the leaf washes by plate counts failed to show an effect of 0.05% tween 80 on the removal of the p ... | 2014 | 24907336 |
| xanthomonas perforans colonization influences salmonella enterica in the tomato phyllosphere. | salmonella enterica rarely grows on healthy, undamaged plants, but its persistence is influenced by bacterial plant pathogens. the interactions between s. enterica, xanthomonas perforans (a tomato bacterial spot pathogen), and tomato were characterized. we observed that virulent x. perforans, which establishes disease by suppressing pathogen-associated molecular pattern (pamp)-triggered immunity that leads to effector-triggered susceptibility, created a conducive environment for persistence of s ... | 2014 | 24632252 |
| salmonella enterica induces and subverts the plant immune system. | infections with salmonella enterica belong to the most prominent causes of food poisoning and infected fruits and vegetables represent important vectors for salmonellosis. although it was shown that plants raise defense responses against salmonella, these bacteria persist and proliferate in various plant tissues. recent reports shed light into the molecular interaction between plants and salmonella, highlighting the defense pathways induced and the means used by the bacteria to escape the plant ... | 2014 | 24772109 |
| quantitative proteomic analysis of the salmonella-lettuce interaction. | human pathogens can internalize food crops through root and surface uptake and persist inside crop plants. the goal of the study was to elucidate the global modulation of bacteria and plant protein expression after salmonella internalizes lettuce. a quantitative proteomic approach was used to analyse the protein expression of salmonella enterica serovar infantis and lettuce cultivar green salad bowl 24 h after infiltrating s. infantis into lettuce leaves. among the 50 differentially expressed pr ... | 2014 | 24512637 |
| uv light inactivation of human and plant pathogens in unfiltered surface irrigation water. | fruit and vegetable growers continually battle plant diseases and food safety concerns. surface water is commonly used in the production of fruits and vegetables and can harbor both human- and plant-pathogenic microorganisms that can contaminate crops when used for irrigation or other agricultural purposes. treatment methods for surface water are currently limited, and there is a need for suitable treatment options. a liquid-processing unit that uses uv light for the decontamination of turbid ju ... | 2014 | 24242253 |
| plant pathogen-induced water-soaking promotes salmonella enterica growth on tomato leaves. | plant pathogen infection is a critical factor for the persistence of salmonella enterica on plants. we investigated the mechanisms responsible for the persistence of s. enterica on diseased tomato plants by using four diverse bacterial spot xanthomonas species that differ in disease severities. xanthomonas euvesicatoria and x. gardneri infection fostered s. enterica growth, while x. perforans infection did not induce growth but supported the persistence of s. enterica. x. vesicatoria-infected le ... | 2015 | 26386057 |
| cilantro microbiome before and after nonselective pre-enrichment for salmonella using 16s rrna and metagenomic sequencing. | salmonella enterica is a common cause of foodborne gastroenteritis in the united states and is associated with outbreaks in fresh produce such as cilantro. salmonella culture-based detection methods are complex and time consuming, and improvments to increase detection sensitivity will benefit consumers. in this study, we used 16s rrna sequencing to determine the microbiome of cilantro. we also investigated changes to the microbial community prior to and after a 24-hour nonselective pre-enrichmen ... | 2015 | 26264042 |
| structural features reminiscent of atp-driven protein translocases are essential for the function of a type iii secretion-associated atpase. | many bacterial pathogens and symbionts utilize type iii secretion systems to interact with their hosts. these machines have evolved to deliver bacterial effector proteins into eukaryotic target cells to modulate a variety of cellular functions. one of the most conserved components of these systems is an atpase, which plays an essential role in the recognition and unfolding of proteins destined for secretion by the type iii pathway. here we show that structural features reminiscent of other atp-d ... | 2015 | 26170413 |
| downy mildew disease promotes the colonization of romaine lettuce by escherichia coli o157:h7 and salmonella enterica. | downy mildew, a plant disease caused by the oomycete bremia lactucae, is endemic in many lettuce-growing regions of the world. invasion by plant pathogens may create new portals and opportunities for microbial colonization of plants. the occurrence of outbreaks of escherichia coli o157:h7 (eco157) and salmonella enterica typhimurium (s. typhimurium) infections linked to lettuce prompted us to investigate the role of downy mildew in the colonization of romaine lettuce by these human pathogens und ... | 2015 | 25648408 |
| the type iii secretion system effector seoc of salmonella enterica subsp. salamae and s. enterica subsp. arizonae adp-ribosylates src and inhibits opsonophagocytosis. | salmonella species utilize type iii secretion systems (t3sss) to translocate effectors into the cytosol of mammalian host cells, subverting cell signaling and facilitating the onset of gastroenteritis. in this study, we compared a draft genome assembly of salmonella enterica subsp. salamae strain 3588/07 against the genomes of s. enterica subsp. enterica serovar typhimurium strain lt2 and salmonella bongori strain 12419. s. enterica subsp. salamae encodes the salmonella pathogenicity island 1 (s ... | 2016 | 27736780 |
| the salmonella effector spvd is a cysteine hydrolase with a serovar-specific polymorphism influencing catalytic activity, suppression of immune responses and bacterial virulence. | many bacterial pathogens secrete virulence (effector) proteins that interfere with immune signaling in their host. spvd is a salmonella enterica effector protein that we previously demonstrated to negatively regulate the nf-κb signaling pathway and promote virulence of s. enterica serovar typhimurium in mice. to shed light on the mechanistic basis for these observations, we determined the crystal structure of spvd and show that it adopts a papain-like fold with a characteristic cysteine-histidin ... | 2016 | 27789710 |
| inhibition of nuclear transport of nf-ĸb p65 by the salmonella type iii secretion system effector spvd. | salmonella enterica replicates in macrophages through the action of effector proteins translocated across the vacuolar membrane by a type iii secretion system (t3ss). here we show that the spi-2 t3ss effector spvd suppresses proinflammatory immune responses. spvd prevented activation of an nf-ĸb-dependent promoter and caused nuclear accumulation of importin-α, which is required for nuclear import of p65. spvd interacted specifically with the exportin xpo2, which mediates nuclear-cytoplasmic recy ... | 2016 | 27232334 |
| flashy flagella: flagellin modification is relatively common and highly versatile among the enterobacteriaceae. | post-translational glycosylation of the flagellin protein is relatively common among gram-negative bacteria, and has been linked to several phenotypes, including flagellar biosynthesis and motility, biofilm formation, host immune evasion and manipulation and virulence. however to date, despite extensive physiological and genetic characterization, it has never been reported for the peritrichously flagellate enterobacteriaceae. | 2016 | 27206480 |
| diguanylate cyclases adra and stm1987 regulate salmonella enterica exopolysaccharide production during plant colonization in an environment-dependent manner. | increasing evidence indicates that despite exposure to harsh environmental stresses, salmonella enterica successfully persists on plants, utilizing fresh produce as a vector to animal hosts. among the important s. enterica plant colonization factors are those involved in biofilm formation. s. enterica biofilm formation is controlled by the signaling molecule cyclic di-gmp and represents a sessile lifestyle on surfaces that protects the bacterium from environmental factors. thus, the transition f ... | 2016 | 26655751 |
| functional dissection of ssef, a membrane-integral effector protein of intracellular salmonella enterica. | during intracellular life, the bacterial pathogen salmonella enterica translocates a complex cocktail of effector proteins by means of the spi2-encoded type iii secretions system. the effectors jointly modify the endosomal system and vesicular transport in host cells. ssef and sseg are two effectors encoded by genes within salmonella pathogenicity island 2 and both effector associate with endosomal membranes and microtubules and are involved in the formation of salmonella-induced filaments. our ... | 2012 | 22529968 |
| salmonella enterica suppresses pectobacterium carotovorum subsp. carotovorum population and soft rot progression by acidifying the microaerophilic environment. | although enteric human pathogens are usually studied in the context of their animal hosts, a significant portion of their life cycle occurs on plants. plant disease alters the phyllosphere, leading to enhanced growth of human pathogens; however, the impact of human pathogens on phytopathogen biology and plant health is largely unknown. to characterize the interaction between human pathogens and phytobacterial pathogens in the phyllosphere, we examined the interactions between pectobacterium caro ... | 2013 | 23404399 |
| surface survival and internalization of salmonella through natural cracks on developing cantaloupe fruits, alone or in the presence of the melon wilt pathogen erwinia tracheiphila. | outbreaks of foodborne illness attributed to the consumption of salmonella-tainted cantaloupe have occurred repeatedly, but understanding of the ecology of salmonella on cantaloupe fruit surfaces is limited. we investigated the interactions between salmonella enterica poona, the plant pathogenic bacterium erwinia tracheiphila, and cantaloupe fruit. fruit surfaces were inoculated at the natural cracking stage by spreading s. enterica and e. tracheiphila, 20 µl at 107 cfu/ml, independently or toge ... | 2014 | 25147942 |
| functional characterization of the type iii secretion atpase ssan encoded by salmonella pathogenicity island 2. | a type iii secretion system (t3ss) is utilized by a large number of gram-negative bacteria to deliver effectors directly into the cytosol of eukaryotic host cells. one essential component of a t3ss is an atpase that catalyzes the unfolding of proteins, which is followed by the translocation of effectors through an injectisome. here we demonstrate a functional role of the atpase ssan, a component of salmonella pathogenicity island 2 t3ss (t3ss-2) in salmonella enterica serovar typhimurium. ssan h ... | 2014 | 24722491 |
| dispersal of human and plant pathogens biofilms via nitric oxide donors at 4 °c. | recent studies suggest that nitric oxide donors capable of manipulating nitric oxide-mediated signaling in bacteria could induce dispersal of biofilms. encased in extracellular polymeric substances, human and plant pathogens within biofilms are significantly more resistant to sanitizers. this is particularly a problem in refrigerated environments where food is processed. in an exercise aimed to study the potential of nitric oxide donors as biofilm dispersal in refrigerated conditions, we compare ... | 2016 | 27457245 |
| functional analysis of bacillus subtilis genes involved in the biosynthesis of 4-thiouridine in trna. | thii has been identified as an essential enzyme involved in the biosynthesis of thiamine and the trna thionucleoside modification, 4-thiouridine. in escherichia coli and salmonella enterica, thii acts as a sulfurtransferase, receiving the sulfur donated from the cysteine desulfurase iscs and transferring it to the target molecule or additional sulfur carrier proteins. however, in bacillus subtilis and most species from the firmicutes phylum, thii lacks the rhodanese domain that contains the site ... | 2012 | 22773787 |
| the calcium-stimulated lipid a 3-o deacylase from rhizobium etli is not essential for plant nodulation. | the lipid a component of lipopolysaccharide from the nitrogen-fixing plant endosymbiont, rhizobium etli, is structurally very different from that found in most enteric bacteria. the lipid a from free-living r. etli is structurally heterogeneous and exists as a mixture of species which are either pentaacylated or tetraacylated. in contrast, the lipid a from r. etli bacteroids is reported to consist exclusively of tetraacylated lipid a species. the tetraacylated lipid a species in both cases lack ... | 2013 | 23583844 |
| generation and selection of anti-flagellin monoclonal antibodies useful for serotyping salmonella enterica. | in developing countries, bacterial acute gastroenteritis continues to be an important cause of morbidity and mortality among young children. salmonellosis constitutes a major cause of infectious enteritis worldwide, most of them associated to the consumption of contaminated food products. traditionally, salmonella has been classified in serovars based on varieties of o and h surface antigens. in the present work we generated and characterized a panel of anti-flagellin monoclonal antibodies (mabs ... | 2013 | 24349948 |
| structural and functional characterization of scsc, a periplasmic thioredoxin-like protein from salmonella enterica serovar typhimurium. | the prototypical protein disulfide bond (dsb) formation and protein refolding pathways in the bacterial periplasm involving dsb proteins have been most comprehensively defined in escherichia coli. however, genomic analysis has revealed several distinct dsb-like systems in bacteria, including the pathogen salmonella enterica serovar typhimurium. this includes the scsabcd locus, which encodes a system that has been shown via genetic analysis to confer copper tolerance, but whose biochemical proper ... | 2013 | 23642141 |
| elucidation of the 3-o-deacylase gene, pagl, required for the removal of primary β-hydroxy fatty acid from the lipid a in the nitrogen-fixing endosymbiont rhizobium etli ce3. | until now, the gene responsible for the 3-o-deacylation of lipid a among nitrogen-fixing endosymbionts has not been characterized. several gram-negative animal pathogens such as salmonella enterica, pseudomonas aeruginosa, and bordetella bronchiseptica contain an outer membrane 3-o-deacylase (pagl) that has been implicated in host immune evasion. the role of 3-o-deacylated lipid a among nitrogen-fixing endosymbionts, plant endophytes, and plant pathogens has not been studied. however, d'haeze et ... | 2013 | 23511636 |
| identification of a third osmoprotectant transport system, the osmu system, in salmonella enterica. | the growth of salmonella enterica serovar typhimurium mutants lacking the prop and prou osmoprotectant transport systems is stimulated by glycine betaine in high-osmolarity media, suggesting that this organism has an additional osmoprotectant transport system. bioinformatic analysis revealed that the genome of this organism contains a hitherto-unidentified operon, designated osmu, consisting of four genes whose products show high similarity to abc-type transport systems for osmoprotectants in ot ... | 2012 | 22609924 |
| a chemical biology approach to interrogate quorum-sensing regulated behaviors at the molecular and cellular level. | small molecule probes have been used extensively to explore biologic systems and elucidate cellular signaling pathways. in this study, we use an inhibitor of bacterial communication to monitor changes in the proteome of salmonella enterica serovar typhimurium with the aim of discovering unrecognized processes regulated by ai-2-based quorum-sensing (qs), a mechanism of bacterial intercellular communication that allows for the coordination of gene expression in a cell density-dependent manner. in ... | 2013 | 23890008 |
| analysis of factors that affect flgm-dependent type iii secretion for protein purification with salmonella enterica serovar typhimurium. | the flgm protein is secreted in response to flagellar hook-basal body secretion and can be used as a secretion signal to direct selected protein secretion via the flagellar type iii secretion (t3s) system [h. m. singer, m. erhardt, a. m. steiner, m. m. zhang, d. yoshikami, g. bulaj, b. m. olivera, and k. t. hughes, mbio 3(3):e00115-12, 2012, http://dx.doi.org/10.1128/mbio.00115-12]. conditions known to affect flagellar gene expression, flgm stability, and flagellar t3s were tested either alone o ... | 2014 | 24706743 |
| deciphering the regulatory circuitry that controls reversible lysine acetylation in salmonella enterica. | in salmonella enterica, the reversible lysine acetylation (rla) system is comprised of the protein acetyltransferase (pat) and sirtuin deacetylase (cobb). rla controls the activities of many proteins, including the acetyl coenzyme a (acetyl-coa) synthetase (acs), by modulating the degree of acs acetylation. we report that iolr, a myo-inositol catabolism repressor, activates the expression of genes encoding components of the rla system. in vitro evidence shows that the iolr protein directly regul ... | 2015 | 26199328 |
| the nsrr regulon in nitrosative stress resistance of salmonella enterica serovar typhimurium. | nitric oxide (no·) is an important mediator of innate immunity. the facultative intracellular pathogen salmonella has evolved mechanisms to detoxify and evade the antimicrobial actions of host-derived no· produced during infection. expression of the no·-detoxifying flavohaemoglobin hmp is controlled by the no·-sensing transcriptional repressor nsrr and is required for salmonella virulence. in this study we show that nsrr responds to very low no· concentrations, suggesting that it plays a primary ... | 2012 | 22831173 |
| bcsz inhibits biofilm phenotypes and promotes virulence by blocking cellulose production in salmonella enterica serovar typhimurium. | cellulose, a 1,4 beta-glucan polysaccharide, is produced by a variety of organisms including bacteria. although the production of cellulose has a high biological, ecological and economical impact, regulatory mechanisms of cellulose biosynthesis are mostly unknown. family eight cellulases are regularly associated with cellulose biosynthesis operons in bacteria; however, their function is poorly characterized. in this study, we analysed the role of the cellulase bcsz encoded by the bcsabzc cellulo ... | 2016 | 27756305 |
| the dub-ious lack of alis in salmonella infection: a salmonella deubiquitinase regulates the autophagy of protein aggregates. | ubiquitinated aggregates are formed in eukaryotic cells in response to several external stimuli, including exposure to bacterial lipopolysaccharide (lps). although salmonella enterica serovar typhimurium (s. typhimurium) lps has been shown to induce aggresome-like induced structures (alis) in macrophages, these have not been described in s. typhimurium-infected macrophages. given that lps is present in infection, this suggests that s. typhimurium might suppress the formation of alis. we found th ... | 2012 | 22931829 |
| type 1 interferon-associated necroptosis: a novel mechanism for salmonella enterica typhimurium to induce macrophage death. | | 2012 | 23147719 |
| the salmonella deubiquitinase ssel inhibits selective autophagy of cytosolic aggregates. | cell stress and infection promote the formation of ubiquitinated aggregates in both non-immune and immune cells. these structures are recognised by the autophagy receptor p62/sequestosome 1 and are substrates for selective autophagy. the intracellular growth of salmonella enterica occurs in a membranous compartment, the salmonella-containing vacuole (scv), and is dependent on effectors translocated to the host cytoplasm by the salmonella pathogenicity island-2 (spi-2) encoded type iii secretion ... | 2012 | 22719249 |
| human genome-wide rnai screen for host factors that modulate intracellular salmonella growth. | salmonella enterica is a bacterial pathogen of humans that can proliferate within epithelial cells as well as professional phagocytes of the immune system. while much has been learned about the microbial genes that influence the infectious process through decades of intensive research, relatively little is known about the host factors that affect infection. we performed a genome-wide sirna screen to identify host genes that salmonella enterica serovar typhimurium (s. typhimurium) utilizes to fac ... | 2012 | 22701604 |
| salmonella enterica: a surprisingly well-adapted intracellular lifestyle. | the infectious intracellular lifestyle of salmonella enterica relies on the adaptation to nutritional conditions within the salmonella-containing vacuole (scv) in host cells. we summarize latest results on metabolic requirements for salmonella during infection. this includes intracellular phenotypes of mutant strains based on metabolic modeling and experimental tests, isotopolog profiling using (13)c-compounds in intracellular salmonella, and complementation of metabolic defects for attenuated m ... | 2012 | 22563326 |