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Sample records for enterocyte effacement pathogenicity

  1. Bacterial-Chromatin Structural Proteins Regulate the Bimodal Expression of the Locus of Enterocyte Effacement (LEE Pathogenicity Island in Enteropathogenic Escherichia coli

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    Hervé Leh

    2017-08-01

    Full Text Available In enteropathogenic Escherichia coli (EPEC, the locus of enterocyte effacement (LEE encodes a type 3 secretion system (T3SS essential for pathogenesis. This pathogenicity island comprises five major operons (LEE1 to LEE5, with the LEE5 operon encoding T3SS effectors involved in the intimate adherence of bacteria to enterocytes. The first operon, LEE1, encodes Ler (LEE-encoded regulator, an H-NS (nucleoid structuring protein paralog that alleviates the LEE H-NS silencing. We observed that the LEE5 and LEE1 promoters present a bimodal expression pattern, depending on environmental stimuli. One key regulator of bimodal LEE1 and LEE5 expression is ler expression, which fluctuates in response to different growth conditions. Under conditions in vitro considered to be equivalent to nonoptimal conditions for virulence, the opposing regulatory effects of H-NS and Ler can lead to the emergence of two bacterial subpopulations. H-NS and Ler share nucleation binding sites in the LEE5 promoter region, but H-NS binding results in local DNA structural modifications distinct from those generated through Ler binding, at least in vitro. Thus, we show how two nucleoid-binding proteins can contribute to the epigenetic regulation of bacterial virulence and lead to opposing bacterial fates. This finding implicates for the first time bacterial-chromatin structural proteins in the bimodal regulation of gene expression.

  2. Bacterial-Chromatin Structural Proteins Regulate the Bimodal Expression of the Locus of Enterocyte Effacement (LEE) Pathogenicity Island in EnteropathogenicEscherichia coli.

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    Leh, Hervé; Khodr, Ahmad; Bouger, Marie-Christine; Sclavi, Bianca; Rimsky, Sylvie; Bury-Moné, Stéphanie

    2017-08-08

    In enteropathogenic Escherichia coli (EPEC), the locus of enterocyte effacement (LEE) encodes a type 3 secretion system (T3SS) essential for pathogenesis. This pathogenicity island comprises five major operons ( LEE1 to LEE5 ), with the LEE5 operon encoding T3SS effectors involved in the intimate adherence of bacteria to enterocytes. The first operon, LEE1 , encodes Ler (LEE-encoded regulator), an H-NS (nucleoid structuring protein) paralog that alleviates the LEE H-NS silencing. We observed that the LEE5 and LEE1 promoters present a bimodal expression pattern, depending on environmental stimuli. One key regulator of bimodal LEE1 and LEE5 expression is ler expression, which fluctuates in response to different growth conditions. Under conditions in vitro considered to be equivalent to nonoptimal conditions for virulence, the opposing regulatory effects of H-NS and Ler can lead to the emergence of two bacterial subpopulations. H-NS and Ler share nucleation binding sites in the LEE5 promoter region, but H-NS binding results in local DNA structural modifications distinct from those generated through Ler binding, at least in vitro Thus, we show how two nucleoid-binding proteins can contribute to the epigenetic regulation of bacterial virulence and lead to opposing bacterial fates. This finding implicates for the first time bacterial-chromatin structural proteins in the bimodal regulation of gene expression. IMPORTANCE Gene expression stochasticity is an emerging phenomenon in microbiology. In certain contexts, gene expression stochasticity can shape bacterial epigenetic regulation. In enteropathogenic Escherichia coli (EPEC), the interplay between H-NS (a nucleoid structuring protein) and Ler (an H-NS paralog) is required for bimodal LEE5 and LEE1 expression, leading to the emergence of two bacterial subpopulations (with low and high states of expression). The two proteins share mutual nucleation binding sites in the LEE5 promoter region. In vitro , the binding of H

  3. The Gene tia, Harbored by the Subtilase-Encoding Pathogenicity Island, Is Involved in the Ability of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli Strains To Invade Monolayers of Epithelial Cells.

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    Bondì, Roslen; Chiani, Paola; Michelacci, Valeria; Minelli, Fabio; Caprioli, Alfredo; Morabito, Stefano

    2017-12-01

    Locus of enterocyte effacement (LEE)-negative Shiga toxin (Stx)-producing Escherichia coli (STEC) strains are human pathogens that lack the LEE locus, a pathogenicity island (PAI) involved in the intimate adhesion of LEE-positive strains to the host gut epithelium. The mechanism used by LEE-negative STEC strains to colonize the host intestinal mucosa is still not clear. The cell invasion determinant tia , previously described in enterotoxigenic E. coli strains, has been identified in LEE-negative STEC strains that possess the subtilase-encoding pathogenicity island (SE-PAI). We evaluated the role of the gene tia , present in these LEE-negative STEC strains, in the invasion of monolayers of cultured cells. We observed that these strains were able to invade Caco-2 and HEp-2 cell monolayers and compared their invasion ability with that of a mutant strain in which the gene tia had been inactivated. Mutation of the gene tia resulted in a strong reduction of the invasive phenotype, and complementation of the tia mutation with a functional copy of the gene restored the invasion activity. Moreover, we show that the gene tia is overexpressed in bacteria actively invading cell monolayers, demonstrating that tia is involved in the ability to invade cultured monolayers of epithelial cells shown by SE-PAI-positive E. coli , including STEC, strains. However, the expression of the tia gene in the E. coli K-12 strain JM109 was not sufficient, in its own right, to confer to this strain the ability to invade cell monolayers, suggesting that at least another factor must be involved in the invasion ability displayed by the SE-PAI-positive strains. Copyright © 2017 American Society for Microbiology.

  4. A Genomic Island in Salmonella enterica ssp. salamae provides new insights on the genealogy of the locus of enterocyte effacement.

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    P Scott Chandry

    Full Text Available The genomic island encoding the locus of enterocyte effacement (LEE is an important virulence factor of the human pathogenic Escherichia coli. LEE typically encodes a type III secretion system (T3SS and secreted effectors capable of forming attaching and effacing lesions. Although prominent in the pathogenic E. coli such as serotype O157:H7, LEE has also been detected in Citrobacter rodentium, E. albertii, and although not confirmed, it is likely to also be in Shigella boydii. Previous phylogenetic analysis of LEE indicated the genomic island was evolving through stepwise acquisition of various components. This study describes a new LEE region from two strains of Salmonella enterica subspecies salamae serovar Sofia along with a phylogenetic analysis of LEE that provides new insights into the likely evolution of this genomic island. The Salmonella LEE contains 36 of the 41 genes typically observed in LEE within a genomic island of 49, 371 bp that encodes a total of 54 genes. A phylogenetic analysis was performed on the entire T3SS and four T3SS genes (escF, escJ, escN, and escV to elucidate the genealogy of LEE. Phylogenetic analysis inferred that the previously known LEE islands are members of a single lineage distinct from the new Salmonella LEE lineage. The previously known lineage of LEE diverged between islands found in Citrobacter and those in Escherichia and Shigella. Although recombination and horizontal gene transfer are important factors in the genealogy of most genomic islands, the phylogeny of the T3SS of LEE can be interpreted with a bifurcating tree. It seems likely that the LEE island entered the Enterobacteriaceae through horizontal gene transfer as a single unit, rather than as separate subsections, which was then subjected to the forces of both mutational change and recombination.

  5. Type Three Secretion System in Attaching and Effacing Pathogens

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    Meztlli Ofelia Gaytán

    2016-10-01

    Full Text Available Enteropathogenic Escherichia coli and enterohemorrhagic E. coli are diarrheagenic bacterial human pathogens that cause severe gastroenteritis. These enteric pathotypes, together with the mouse pathogen Citrobacter rodentium, belong to the family of attaching and effacing pathogens that form a distinctive histological lesion in the intestinal epithelium. The virulence of these bacteria depends on a type III secretion system (T3SS, which mediates the translocation of effector proteins from the bacterial cytosol into the infected cells. The core architecture of the T3SS consists of a multi-ring basal body embedded in the bacterial membranes, a periplasmic inner rod, a transmembrane export apparatus in the inner membrane, and cytosolic components including an ATPase complex and the C-ring. In addition, two distinct hollow appendages are assembled on the extracellular face of the basal body creating a channel for protein secretion: an approximately 23 nm needle, and a filament that extends up to 600 nm. This filamentous structure allows these pathogens to get through the host cells mucus barrier. Upon contact with the target cell, a translocation pore is assembled in the host membrane through which the effector proteins are injected. Assembly of the T3SS is strictly regulated to ensure proper timing of substrate secretion. The different type III substrates coexist in the bacterial cytoplasm, and their hierarchical secretion is determined by specialized chaperones in coordination with two molecular switches and the so-called sorting platform. In this review, we present recent advances in the understanding of the T3SS in attaching and effacing pathogens.

  6. Type Three Secretion System in Attaching and Effacing Pathogens

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    Gaytán, Meztlli O.; Martínez-Santos, Verónica I.; Soto, Eduardo; González-Pedrajo, Bertha

    2016-01-01

    Enteropathogenic Escherichia coli and enterohemorrhagic E. coli are diarrheagenic bacterial human pathogens that cause severe gastroenteritis. These enteric pathotypes, together with the mouse pathogen Citrobacter rodentium, belong to the family of attaching and effacing pathogens that form a distinctive histological lesion in the intestinal epithelium. The virulence of these bacteria depends on a type III secretion system (T3SS), which mediates the translocation of effector proteins from the bacterial cytosol into the infected cells. The core architecture of the T3SS consists of a multi-ring basal body embedded in the bacterial membranes, a periplasmic inner rod, a transmembrane export apparatus in the inner membrane, and cytosolic components including an ATPase complex and the C-ring. In addition, two distinct hollow appendages are assembled on the extracellular face of the basal body creating a channel for protein secretion: an approximately 23 nm needle, and a filament that extends up to 600 nm. This filamentous structure allows these pathogens to get through the host cells mucus barrier. Upon contact with the target cell, a translocation pore is assembled in the host membrane through which the effector proteins are injected. Assembly of the T3SS is strictly regulated to ensure proper timing of substrate secretion. The different type III substrates coexist in the bacterial cytoplasm, and their hierarchical secretion is determined by specialized chaperones in coordination with two molecular switches and the so-called sorting platform. In this review, we present recent advances in the understanding of the T3SS in attaching and effacing pathogens. PMID:27818950

  7. The Small Regulatory RNA Spot42 Inhibits Indole Biosynthesis to Negatively Regulate the Locus of Enterocyte Effacement of Enteropathogenic Escherichia coli

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    Shantanu Bhatt

    2017-12-01

    Full Text Available The locus of enterocyte effacement is necessary for enteropathogenic Escherichia coli (EPEC to form attaching and effacing (A/E lesions. A/E lesions are characterized by intimate bacterial adherence to intestinal cells and destruction of microvilli, which leads to diarrhea. Therefore, studies interrogating the regulation of the locus of enterocyte effacement (LEE are critical for understanding the molecular epidemiology of EPEC infections and developing interventional strategies. Hitherto, most studies have centered on protein-based regulators, whereas the role of small regulatory RNAs remains underappreciated. Previously, we identified the first sRNAs—MgrR, RyhB, and McaS—that regulate the LEE of EPEC. This study was undertaken to identify additional sRNAs that impact the LEE. Our results suggest that the catabolite-responsive sRNA, Spot42, indirectly controls the LEE by inhibiting synthesis of its inducer, indole. Spot42 base-pairs with the tnaCAB mRNA and presumably destabilizes the transcript, thereby preventing expression of the regulatory and structural proteins that are involved in the import and hydrolysis of tryptophan into indole. The absence of intracellular indole leads to reduced transcription of the LEE1-encoded master transcriptional activator Ler, thereby maintaining the LEE in its silenced state and delaying A/E lesion morphogenesis. Our results highlight the importance of riboregulators that synchronize metabolic and virulence pathways in bacterial infection.

  8. The two-component system CpxRA negatively regulates the Locus of Enterocyte Effacement of enterohemorrhagic Escherichia coli involving sigma 32 and Lon protease

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    MIGUEL A. eDE LA CRUZ

    2016-02-01

    Full Text Available Enterohemorrhagic Escherichia coli (EHEC is a significant cause of serious human gastrointestinal disease worldwide. EHEC strains contain a pathogenicity island called the locus of enterocyte effacement (LEE, which encodes virulence factors responsible for damaging the gut mucosa. The Cpx envelope stress response of E. coli is controlled by a two-component system consisting of a sensor histidine kinase (CpxA and a cytoplasmic response regulator (CpxR. In this study, we investigated the role of CpxRA in the expression of LEE-encoded virulence factors of EHEC. We found that a mutation in cpxA significantly affected adherence of EHEC to human epithelial cells. Analysis of this mutant revealed the presence of high levels of CpxR which repressed transcription of grlA and ler, the main positive virulence regulators of the LEE, and influenced negatively the production of the type 3 secretion system–associated EspABD translocator proteins. It is known that CpxR activates rpoH (Sigma factor 32, which in turns activates transcription of the lon protease gene. We found that transcription levels of ler and grlA were significantly increased in the lon and cpxA lon mutants suggesting that lon is involved in down-regulating LEE genes. In addition, the Galleria mellonella model of infection was used to analyze the effect of the loss of the cpx and lon genes in EHEC’s ability to kill the larvae. We found that the cpxA mutant was significantly deficient at killing the larvae however, the cpxA lon mutant which overexpresses LEE genes in vitro, was unable to kill the larvae, suggesting that virulence in the G. mellonella model is T3SS independent and that CpxA modulates virulence through a yet unknown EHEC-specific factor. Our data provides new insights and broadens our scope into the complex regulatory network of the LEE in which the CpxA sensor kinase plays an important role in a cascade involving both global and virulence regulators.

  9. The Two-Component System CpxRA Negatively Regulates the Locus of Enterocyte Effacement of Enterohemorrhagic Escherichia coli Involving σ(32) and Lon protease.

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    De la Cruz, Miguel A; Morgan, Jason K; Ares, Miguel A; Yáñez-Santos, Jorge A; Riordan, James T; Girón, Jorge A

    2016-01-01

    Enterohemorrhagic Escherichia coli (EHEC) is a significant cause of serious human gastrointestinal disease worldwide. EHEC strains contain a pathogenicity island called the locus of enterocyte effacement (LEE), which encodes virulence factors responsible for damaging the gut mucosa. The Cpx envelope stress response of E. coli is controlled by a two-component system (TCS) consisting of a sensor histidine kinase (CpxA) and a cytoplasmic response regulator (CpxR). In this study, we investigated the role of CpxRA in the expression of LEE-encoded virulence factors of EHEC. We found that a mutation in cpxA significantly affected adherence of EHEC to human epithelial cells. Analysis of this mutant revealed the presence of high levels of CpxR which repressed transcription of grlA and ler, the main positive virulence regulators of the LEE, and influenced negatively the production of the type 3 secretion system-associated EspABD translocator proteins. It is known that CpxR activates rpoH (Sigma factor 32), which in turns activates transcription of the lon protease gene. We found that transcription levels of ler and grlA were significantly increased in the lon and cpxA lon mutants suggesting that lon is involved in down-regulating LEE genes. In addition, the Galleria mellonella model of infection was used to analyze the effect of the loss of the cpx and lon genes in EHEC's ability to kill the larvae. We found that the cpxA mutant was significantly deficient at killing the larvae however, the cpxA lon mutant which overexpresses LEE genes in vitro, was unable to kill the larvae, suggesting that virulence in the G. mellonella model is T3SS independent and that CpxA modulates virulence through a yet unknown EHEC-specific factor. Our data provides new insights and broadens our scope into the complex regulatory network of the LEE in which the CpxA sensor kinase plays an important role in a cascade involving both global and virulence regulators.

  10. Aquaporins contribute to diarrhoea caused by attaching and effacing bacterial pathogens.

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    Guttman, Julian A; Samji, Fereshte N; Li, Yuling; Deng, Wanyin; Lin, Ann; Finlay, B Brett

    2007-01-01

    Attaching and effacing (A/E) pathogens such as enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) cause serious global health problems. These bacteria colonize the gastrointestinal system, attach to intestinal epithelial cells, efface (collapse) infected cell microvilli and cause overt diarrhoea that may ultimately result in death of the host. Although pathogenically induced diarrhoea is a significant global health issue, the molecular mechanisms that underlie this disease remain largely unknown. A natural murine infection model, employing the A/E pathogen Citrobacter rodentium, has been helpful in studying the diseases in vivo. C. rodentium colonize the colon at high levels, attach to colonocytes, efface microvilli and cause hyperplasia and inflammation in infected mice. As the disease progresses, the mice develop a diarrhoea-like phenotype. Aquaporin (AQP) water channels have been proposed to play a role in the normal dehydration of faecal contents. Here we examine whether C. rodentium infection may alter AQP localization in colonocytes. We demonstrate that during infection, AQP2 and AQP3 are mislocalized from their normal location along cell membranes to the cell cytoplasm. The change in localization of these proteins correlates with the diarrhoea-like phenotype present in infected mice. Mice that recover from the infection at 28-35 days post inoculum regain their normal membrane AQP localization. The altered localization of AQPs is partially dependent on the bacterial type III effector proteins EspF and EspG. We conclude that altered AQP localization may be a contributing factor to diarrhoea during bacterial infection.

  11. RcsB determines the locus of enterocyte effacement (LEE) expression and adherence phenotype of Escherichia coli O157 : H7 spinach outbreak strain TW14359 and coordinates bicarbonate-dependent LEE activation with repression of motility.

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    Morgan, Jason K; Vendura, Khoury W; Stevens, Stanley M; Riordan, James T

    2013-11-01

    The 2006 US spinach outbreak of Escherichia coli O157 : H7, characterized by unusually severe disease, has been attributed to a strain (TW14359) with enhanced pathogenic potential, including elevated virulence gene expression, robust adherence and the presence of novel virulence factors. This study proposes a mechanism for the unique virulence expression and adherence phenotype of this strain, and further expands the role for regulator RcsB in control of the E. coli locus of enterocyte effacement (LEE) pathogenicity island. Proteomic analysis of TW14359 revealed a virulence proteome consistent with previous transcriptome studies that included elevated levels of the LEE regulatory protein Ler and type III secretion system (T3SS) proteins, secreted T3SS effectors and Shiga toxin 2. Basal levels of the LEE activator and Rcs phosphorelay response regulator, RcsB, were increased in strain TW14359 relative to O157 : H7 strain Sakai. Deletion of rcsB eliminated inherent differences between these strains in ler expression, and in T3SS-dependent adherence. A reciprocating regulatory pathway involving RcsB and LEE-encoded activator GrlA was identified and predicted to co-ordinate LEE activation with repression of the flhDC flagellar regulator and motility. Overexpression of grlA was shown to increase RcsB levels, but did not alter expression from promoters driving rcsB transcription. Expression of rcsDB and RcsB was determined to increase in response to physiological levels of bicarbonate, and bicarbonate-dependent stimulation of the LEE was shown to be dependent on an intact Rcs system and ler activator grvA. The results of this study significantly broaden the role for RcsB in enterohaemorrhagic E. coli virulence regulation.

  12. Hfq and three Hfq-dependent small regulatory RNAs-MgrR, RyhB and McaS-coregulate the locus of enterocyte effacement in enteropathogenic Escherichia coli.

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    Bhatt, Shantanu; Egan, Marisa; Ramirez, Jasmine; Xander, Christian; Jenkins, Valerie; Muche, Sarah; El-Fenej, Jihad; Palmer, Jamie; Mason, Elisabeth; Storm, Elizabeth; Buerkert, Thomas

    2017-02-01

    Enteropathogenic Escherichia coli (EPEC) is a significant cause of infantile diarrhea and death in developing countries. The pathogenicity island locus of enterocyte effacement (LEE) is essential for EPEC to cause diarrhea. Besides EPEC, the LEE is also present in other gastrointestinal pathogens, most notably enterohemorrhagic E. coli (EHEC). Whereas transcriptional control of the LEE has been meticulously examined, posttranscriptional regulation, including the role of Hfq-dependent small RNAs, remains undercharacterized. However, the past few years have witnessed a surge in the identification of riboregulators of the LEE in EHEC. Contrastingly, the posttranscriptional regulatory landscape of EPEC remains cryptic. Here we demonstrate that the RNA-chaperone Hfq represses the LEE of EPEC by targeting the 5' untranslated leader region of grlR in the grlRA mRNA. Three conserved small regulatory RNAs (sRNAs)-MgrR, RyhB and McaS-are involved in the Hfq-dependent regulation of grlRA MgrR and RyhB exert their effects by directly base-pairing to the 5' region of grlR Whereas MgrR selectively represses grlR but activates grlA, RyhB represses gene expression from the entire grlRA transcript. Meanwhile, McaS appears to target the grlRA mRNA indirectly. Thus, our results provide the first definitive evidence that implicates multiple sRNAs in regulating the LEE and the resulting virulence of EPEC. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Subversion of actin dynamics by EspM effectors of attaching and effacing bacterial pathogens

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    Arbeloa, Ana; Bulgin, Richard R; MacKenzie, Georgina; Shaw, Robert K; Pallen, Mark J; Crepin, Valerie F; Berger, Cedric N; Frankel, Gad

    2008-01-01

    Rho GTPases are common targets of bacterial toxins and type III secretion system effectors. IpgB1 and IpgB2 of Shigella and Map of enteropathogenic (EPEC) and enterohemorrhagic (EHEC) Escherichia coli were recently grouped together on the basis that they share a conserved WxxxE motif. In this study, we characterized six WxxxE effectors from attaching and effacing pathogens: TrcA and EspM1 of EPEC strain B171, EspM1 and EspM2 of EHEC strain Sakai and EspM2 and EspM3 of Citrobacter rodentium. W...

  14. Lambda Red-mediated Recombineering in the Attaching and Effacing Pathogen Escherichia albertii.

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    Egan, Marisa; Ramirez, Jasmine; Xander, Christian; Upreti, Chirag; Bhatt, Shantanu

    2016-01-01

    The ability to introduce site-specific mutations in bacterial pathogens is essential towards understanding their molecular mechanisms of pathogenicity. This has been greatly facilitated by the genetic engineering technique of recombineering. In recombineering, linear double- or single-stranded DNA molecules with two terminal homology arms are electroporated into hyperrecombinogenic bacteria that express a phage-encoded recombinase. The recombinase catalyzes the replacement of the endogenous allele with the exogenous allele to generate selectable or screenable recombinants. In particular, lambda red recombinase has been instrumental in engineering mutations to characterize the virulence arsenal of the attaching and effacing (A/E) pathogens enteropathogenic Escherichia coli (EPEC), enterohemorrhagic E. coli (EHEC), and Citrobacter rodentium. Escherichia albertii is another member of this taxon; however, the virulence of E. albertii remains cryptic despite accumulating evidence that E. albertii is an emerging pathogen. Multiple retrospective studies have reported that a substantial number of EPEC and EHEC isolates (~15 %) that were previously incriminated in human outbreaks actually belong to the E. albertii lineage. Thus, there is increased urgency to reliably identify and rapidly engineer mutations in E. albertii to systematically characterize its virulence determinants. To the best of our knowledge not a single chromosomal gene has been altered by targeted mutagenesis in E. albertii since it was first isolated almost 25 years ago. This is disconcerting because an E. albertii outbreak could cause significant morbidity and mortality owing to our inadequate understanding of its virulence program. In this report we describe a modified lambda red recombineering protocol to mutagenize E. albertii. As proof of principle, we successfully deleted three distinct virulence-associated genetic loci - ler, grlRA, and hfq - and replaced each wild type allele by a mutant allele

  15. Subversion of actin dynamics by EspM effectors of attaching and effacing bacterial pathogens.

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    Arbeloa, Ana; Bulgin, Richard R; MacKenzie, Georgina; Shaw, Robert K; Pallen, Mark J; Crepin, Valerie F; Berger, Cedric N; Frankel, Gad

    2008-07-01

    Rho GTPases are common targets of bacterial toxins and type III secretion system effectors. IpgB1 and IpgB2 of Shigella and Map of enteropathogenic (EPEC) and enterohemorrhagic (EHEC) Escherichia coli were recently grouped together on the basis that they share a conserved WxxxE motif. In this study, we characterized six WxxxE effectors from attaching and effacing pathogens: TrcA and EspM1 of EPEC strain B171, EspM1 and EspM2 of EHEC strain Sakai and EspM2 and EspM3 of Citrobacter rodentium. We show that EspM2 triggers formation of global parallel stress fibres, TrcA and EspM1 induce formation of localized parallel stress fibres and EspM3 triggers formation of localized radial stress fibres. Using EspM2 and EspM3 as model effectors, we report that while substituting the conserved Trp with Ala abolished activity, conservative Trp to Tyr or Glu to Asp substitutions did not affect stress-fibre formation. We show, using dominant negative constructs and chemical inhibitors, that the activity of EspM2 and EspM3 is RhoA and ROCK-dependent. Using Rhotekin pull-downs, we have shown that EspM2 and EspM3 activate RhoA; translocation of EspM2 and EspM3 triggered phosphorylation of cofilin. These results suggest that the EspM effectors modulate actin dynamics by activating the RhoA signalling pathway.

  16. Xylo-oligosaccharides inhibit pathogen adhesion to enterocytes in vitro

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    Ebersbach, Tine; Andersen, Jens Bo; Bergström, Anders

    2012-01-01

    We previously reported that the non-digestible carbohydrates inulin and apple pectin promoted Listeria monocytogenes infection in guinea pigs, whereas xylo- and galacto-oligosaccharides (XOS and GOS), prevented infection by this pathogen. In the present study, mechanisms that could explain...

  17. Impact of Infection Dose and Previous Serum Antibodies against the Locus of Enterocyte Effacement Proteins on Escherichia coli O157:H7 Shedding in Calves following Experimental Infection

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    L. Martorelli

    2015-01-01

    Full Text Available Escherichia coli O157:H7 is the main causative agent of haemolytic uremic syndrome. Cattle are the main reservoir of these bacteria, and have been shown to develop immune response to colonization. Our aim was to investigate the faecal shedding pattern of E. coli O157:H7 in calves challenged intragastrically with either 108 or 1010 CFU, as well as the ability of specific preexisting antibodies to reduce shedding of the pathogen. Shedding was analysed by direct counting as well as enrichment of rectoanal mucosal swabs. Statistical analysis was performed using a linear model for repeated measures with and without the inclusion of preexisting antibodies against the carboxy-terminal fraction of intimin-γ (γ-intimin C280 as a covariable. Results suggest that there is a statistical difference in the area under the shedding curves between both doses for 14 as well as 28 days after challenge (p = 0.0069 and 0.0209, resp.. This difference is increased when the prechallenge antibodies are taken into account (p = 0.0056 and 0.0185. We concluded that the bacterial dose influences shedding on calves experimentally challenged and that preexisting antibodies against E. coli O157:H7 γ-intimin C280 could partially reduce faecal excretion.

  18. Use of Antibody Responses against Locus of Enterocyte Effacement (LEE)-Encoded Antigens To Monitor Enterohemorrhagic Escherichia coli Infections on Cattle Farms

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    Joris, Maria-Adelheid; Vanrompay, Daisy; Verstraete, Karen; De Reu, Koen; De Zutter, Lieven

    2013-01-01

    Enterohemorrhagic Escherichia coli (EHEC) is a significant zoonotic pathogen causing severe disease associated with watery and bloody diarrhea, hemorrhagic colitis, and the hemolytic-uremic syndrome (HUS) in humans. Infections are frequently associated with contact with EHEC-contaminated ruminant feces. Both natural and experimental infection of cattle induces serum antibodies against the LEE-encoded proteins intimin, EspA, EspB, and Tir and the Shiga toxins Stx1 and Stx2, although the latter are poorly immunogenic in cattle. We determined whether antibodies and/or the kinetics of antibody responses against intimin, Tir, EspA, and/or EspB can be used for monitoring EHEC infections in beef cattle herds in order to reduce carcass contamination at slaughter. We examined the presence of serum antibodies against recombinant O157:H7 E. coli intimin EspA, EspB, and Tir during a cross-sectional study on 12 cattle farms and during a longitudinal time course study on two EHEC-positive cattle farms. We searched for a possible correlation between intimin, Tir, EspA, and/or EspB antibodies and fecal excretion of EHEC O157, O145, O111, O103, or O26 seropathotypes. The results indicated that serum antibody responses to EspB and EspA might be useful for first-line screening at the herd level for EHEC O157, O26, and most likely also for EHEC O103 infections. However, antibody responses against EspB are of less use for monitoring individual animals, since some EHEC-shedding animals did not show antibody responses and since serum antibody responses against EspB could persist for several months even when shedding had ceased. PMID:23563950

  19. Insights into the pathogenesis of enteropathogenic E. coli using an improved intestinal enterocyte model.

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    Paul Dean

    Full Text Available Enteropathogenic E. coli (EPEC is a human pathogen that targets the small intestine, causing severe and often fatal diarrhoea in infants. A defining feature of EPEC disease is the loss (effacement of absorptive microvilli (MV from the surface of small intestinal enterocytes. Much of our understanding of EPEC pathogenesis is derived from studies using cell lines such as Caco-2 - the most extensively used small intestinal model. However, previous work has revealed fundamental differences between Caco-2 cells and in vivo differentiated enterocytes in relation to MV effacement. This, and the high heterogeneity and low transfection efficiency of the Caco-2 cell line prompted the isolation of several sub-clones (NCL-1-12 to identify a more tractable and improved in vivo-like cell model. Along with established Caco-2 clones (TC-7, BBE1, sub-clones were assessed for growth rate, apical surface morphology, epithelial barrier function and transfection efficiency. TC-7 cells provided the best all-round clone and exhibited highest levels of ectopic gene expression following cell polarisation. Novel alterations in EGFP-labelled mitochondria, that were not previously documented in non-polarised cell types, highlighted the potential of the TC-7 model for defining dynamic enterocyte-specific changes during infection. Crucially, the TC-7 cell line also mimicked ex vivo derived enterocytes with regard to MV effacement, enabling a better dissection of the process. Effacement activity caused by the EPEC protein Map in the Caco-2 but not ex vivo model, was linked to a defect in suppressing its Cdc42-dependent functionality. MV effacement activity of the EPEC protein EspF in the TC-7 model was dependent on its N-WASP binding motif, which is also shown to play an essential role in epithelial barrier dysfunction. Together, this study highlights the many advantages of using TC-7 cells as a small intestinal model to study host-pathogen interactions.

  20. Lambda Red-mediated Recombineering in the Attaching and Effacing Pathogen Escherichia albertii

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    Egan, Marisa; Ramirez, Jasmine; Xander, Christian; Upreti, Chirag; Bhatt, Shantanu

    2016-01-01

    Background The ability to introduce site-specific mutations in bacterial pathogens is essential towards understanding their molecular mechanisms of pathogenicity. This has been greatly facilitated by the genetic engineering technique of recombineering. In recombineering, linear double- or single-stranded DNA molecules with two terminal homology arms are electroporated into hyperrecombinogenic bacteria that express a phage-encoded recombinase. The recombinase catalyzes the replacement of the e...

  1. Quantitative Proteomic Analysis of Type III Secretome of Enteropathogenic Escherichia coli Reveals an Expanded Effector Repertoire for Attaching/Effacing Bacterial Pathogens*

    Science.gov (United States)

    Deng, Wanyin; Yu, Hong B.; de Hoog, Carmen L.; Stoynov, Nikolay; Li, Yuling; Foster, Leonard J.; Finlay, B. Brett

    2012-01-01

    Type III secretion systems are central to the pathogenesis and virulence of many important Gram-negative bacterial pathogens, and elucidation of the secretion mechanism and identification of the secreted substrates are critical to our understanding of their pathogenic mechanisms and developing potential therapeutics. Stable isotope labeling with amino acids in cell culture-based mass spectrometry is a quantitative and highly sensitive proteomics tool that we have previously used to successfully analyze the type III secretomes of Citrobacter rodentium and Salmonella enterica serovar Typhimurium. In this report, stable isotope labeling with amino acids in cell culture was used to analyze the type III secretome of enteropathogenic Escherichia coli (EPEC), an important human pathogen, which, together with enterohemorrhagic E. coli and C. rodentium, represents the family of attaching and effacing bacterial pathogens. We not only confirmed all 25 known EPEC type III-secreted proteins and effectors previously identified by conventional molecular and bioinformatical techniques but also identified several new type III-secreted proteins, including two novel effectors, C_0814/NleJ and LifA, that were shown to be translocated into host cells. LifA is a known virulence factor believed to act as a toxin as well as an adhesin, but its mechanism of secretion and function is not understood. With a predicted molecular mass of 366 kDa, LifA is the largest type III effector identified thus far in any pathogen. We further demonstrated that Efa1, ToxB, and Z4332 (homologs of LifA in enterohemorrhagic E. coli) are also type III effectors. This study has comprehensively characterized the type III secretome of EPEC, expanded the repertoire of type III-secreted effectors for the attaching and effacing pathogens, and provided new insights into the mode of function for LifA/Efa1/ToxB/Z4332, an important family of virulence factors. PMID:22661456

  2. Quantitative proteomic analysis of type III secretome of enteropathogenic Escherichia coli reveals an expanded effector repertoire for attaching/effacing bacterial pathogens.

    Science.gov (United States)

    Deng, Wanyin; Yu, Hong B; de Hoog, Carmen L; Stoynov, Nikolay; Li, Yuling; Foster, Leonard J; Finlay, B Brett

    2012-09-01

    Type III secretion systems are central to the pathogenesis and virulence of many important Gram-negative bacterial pathogens, and elucidation of the secretion mechanism and identification of the secreted substrates are critical to our understanding of their pathogenic mechanisms and developing potential therapeutics. Stable isotope labeling with amino acids in cell culture-based mass spectrometry is a quantitative and highly sensitive proteomics tool that we have previously used to successfully analyze the type III secretomes of Citrobacter rodentium and Salmonella enterica serovar Typhimurium. In this report, stable isotope labeling with amino acids in cell culture was used to analyze the type III secretome of enteropathogenic Escherichia coli (EPEC), an important human pathogen, which, together with enterohemorrhagic E. coli and C. rodentium, represents the family of attaching and effacing bacterial pathogens. We not only confirmed all 25 known EPEC type III-secreted proteins and effectors previously identified by conventional molecular and bioinformatical techniques but also identified several new type III-secreted proteins, including two novel effectors, C_0814/NleJ and LifA, that were shown to be translocated into host cells. LifA is a known virulence factor believed to act as a toxin as well as an adhesin, but its mechanism of secretion and function is not understood. With a predicted molecular mass of 366 kDa, LifA is the largest type III effector identified thus far in any pathogen. We further demonstrated that Efa1, ToxB, and Z4332 (homologs of LifA in enterohemorrhagic E. coli) are also type III effectors. This study has comprehensively characterized the type III secretome of EPEC, expanded the repertoire of type III-secreted effectors for the attaching and effacing pathogens, and provided new insights into the mode of function for LifA/Efa1/ToxB/Z4332, an important family of virulence factors.

  3. Locus of Adhesion and Autoaggregation (LAA), a pathogenicity island present in emerging Shiga Toxin?producing Escherichia coli strains

    OpenAIRE

    Montero, David A.; Velasco, Juliana; Del Canto, Felipe; Puente, Jose L.; Padola, Nora L.; Rasko, David A.; Farf?n, Mauricio; Salazar, Juan C.; Vidal, Roberto

    2017-01-01

    Shiga Toxin-producing Escherichia coli (STEC) are a group of foodborne pathogens associated with diarrhea, dysentery, hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). Shiga toxins are the major virulence factor of these pathogens, however adhesion and colonization to the human intestine is required for STEC pathogenesis. A subset of STEC strains carry the Locus of Enterocyte Effacement (LEE) pathogenicity island (PAI), which encodes genes that mediate the colonization of the huma...

  4. Restrictive Streptomycin Resistance Mutations Decrease the Formation of Attaching and Effacing Lesions in Escherichia coli O157:H7 Strains.

    Science.gov (United States)

    Chen, Chun; Blumentritt, Carla A; Curtis, Meredith M; Sperandio, Vanessa; Torres, Alfredo G; Dudley, Edward G

    2013-09-01

    Streptomycin binds to the bacterial ribosome and disrupts protein synthesis by promoting misreading of mRNA. Restrictive mutations on the ribosomal subunit protein S12 confer a streptomycin resistance (Str r ) phenotype and concomitantly increase the accuracy of the decoding process and decrease the rate of translation. Spontaneous Str r mutants of Escherichia coli O157:H7 have been generated for in vivo studies to promote colonization and to provide a selective marker for this pathogen. The locus of enterocyte effacement (LEE) of E. coli O157:H7 encodes a type III secretion system (T3SS), which is required for attaching and effacing to the intestinal epithelium. In this study, we observed decreases in both the expression and secretion levels of the T3SS translocated proteins EspA and EspB in E. coli O157:H7 Str r restrictive mutants, which have K42T or K42I mutations in S12. However, mildly restrictive (K87R) and nonrestrictive (K42R) mutants showed slight or indistinguishable changes in EspA and EspB secretion. Adherence and actin staining assays indicated that restrictive mutations compromised the formation of attaching and effacing lesions in E. coli O157:H7. Therefore, we suggest that E. coli O157:H7 strains selected for Str r should be thoroughly characterized before in vivo and in vitro experiments that assay for LEE-directed phenotypes and that strains carrying nonrestrictive mutations such as K42R make better surrogates of wild-type strains than those carrying restrictive mutations. Copyright © 2013, American Society for Microbiology. All Rights Reserved.

  5. Global Regulator of Virulence A (GrvA) Coordinates Expression of Discrete Pathogenic Mechanisms in Enterohemorrhagic Escherichia coli through Interactions with GadW-GadE

    OpenAIRE

    Morgan, Jason K.; Carroll, Ronan K.; Harro, Carly M.; Vendura, Khoury W.; Shaw, Lindsey N.; Riordan, James T.

    2016-01-01

    Global regulator of virulence A (GrvA) is a ToxR-family transcriptional regulator that activates locus of enterocyte effacement (LEE)-dependent adherence in enterohemorrhagic Escherichia coli (EHEC). LEE activation by GrvA requires the Rcs phosphorelay response regulator RcsB and is sensitive to physiologically relevant concentrations of bicarbonate, a known stimulant of virulence systems in intestinal pathogens. This study determines the genomic scale of GrvA-dependent regulation and uncover...

  6. H-NST induces LEE expression and the formation of attaching and effacing lesions in enterohemorrhagic Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Jonathan A Levine

    Full Text Available Enteropathogenic E. coli (EPEC and enterohemorrhagic E. coli are important causes of morbidity and mortality worldwide. These enteric pathogens contain a type III secretion system (T3SS responsible for the attaching and effacing (A/E lesion phenotype. The T3SS is encoded by the locus of enterocyte effacement (LEE pathogenicity island. The H-NS-mediated repression of LEE expression is counteracted by Ler, the major activator of virulence gene expression in A/E pathogens. A regulator present in EPEC, H-NST, positively affects expression of H-NS regulon members in E. coli K-12, although the effect of H-NST on LEE expression and virulence of A/E pathogens has yet-to-be determined.We examine the effect of H-NST on LEE expression and A/E lesion formation on intestinal epithelial cells. We find that H-NST positively affects the levels of LEE-encoded proteins independently of ler and induces A/E lesion formation. We demonstrate H-NST binding to regulatory regions of LEE1 and LEE3, the first report of DNA-binding by H-NST. We characterize H-NST mutants substituted at conserved residues including Ala16 and residues Arg60 and Arg63, which are part of a potential DNA-binding domain. The single mutants A16V, A16L, R60Q and the double mutant R60Q/R63Q exhibit a decreased effect on LEE expression and A/E lesion formation. DNA mobility shift assays reveal that these residues are important for H-NST to bind regulatory LEE DNA targets. H-NST positively affects Ler binding to LEE DNA in the presence of H-NS, and thereby potentially helps Ler displace H-NS bound to DNA.H-NST induces LEE expression and A/E lesion formation likely by counteracting H-NS-mediated repression. We demonstrate that H-NST binds to DNA and identify arginine residues that are functionally important for DNA-binding. Our study suggests that H-NST provides an additional means for A/E pathogens to alleviate repression of virulence gene expression by H-NS to promote virulence capabilities.

  7. H-NST induces LEE expression and the formation of attaching and effacing lesions in enterohemorrhagic Escherichia coli.

    Science.gov (United States)

    Levine, Jonathan A; Hansen, Anne-Marie; Michalski, Jane M; Hazen, Tracy H; Rasko, David A; Kaper, James B

    2014-01-01

    Enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli are important causes of morbidity and mortality worldwide. These enteric pathogens contain a type III secretion system (T3SS) responsible for the attaching and effacing (A/E) lesion phenotype. The T3SS is encoded by the locus of enterocyte effacement (LEE) pathogenicity island. The H-NS-mediated repression of LEE expression is counteracted by Ler, the major activator of virulence gene expression in A/E pathogens. A regulator present in EPEC, H-NST, positively affects expression of H-NS regulon members in E. coli K-12, although the effect of H-NST on LEE expression and virulence of A/E pathogens has yet-to-be determined. We examine the effect of H-NST on LEE expression and A/E lesion formation on intestinal epithelial cells. We find that H-NST positively affects the levels of LEE-encoded proteins independently of ler and induces A/E lesion formation. We demonstrate H-NST binding to regulatory regions of LEE1 and LEE3, the first report of DNA-binding by H-NST. We characterize H-NST mutants substituted at conserved residues including Ala16 and residues Arg60 and Arg63, which are part of a potential DNA-binding domain. The single mutants A16V, A16L, R60Q and the double mutant R60Q/R63Q exhibit a decreased effect on LEE expression and A/E lesion formation. DNA mobility shift assays reveal that these residues are important for H-NST to bind regulatory LEE DNA targets. H-NST positively affects Ler binding to LEE DNA in the presence of H-NS, and thereby potentially helps Ler displace H-NS bound to DNA. H-NST induces LEE expression and A/E lesion formation likely by counteracting H-NS-mediated repression. We demonstrate that H-NST binds to DNA and identify arginine residues that are functionally important for DNA-binding. Our study suggests that H-NST provides an additional means for A/E pathogens to alleviate repression of virulence gene expression by H-NS to promote virulence capabilities.

  8. Attaching and effacing (A/E) lesion formation by enteropathogenic E. coli on human intestinal mucosa is dependent on non-LEE effectors.

    Science.gov (United States)

    Cepeda-Molero, Massiel; Berger, Cedric N; Walsham, Alistair D S; Ellis, Samuel J; Wemyss-Holden, Simon; Schüller, Stephanie; Frankel, Gad; Fernández, Luis Ángel

    2017-10-01

    Enteropathogenic E. coli (EPEC) is a human pathogen that causes acute and chronic pediatric diarrhea. The hallmark of EPEC infection is the formation of attaching and effacing (A/E) lesions in the intestinal epithelium. Formation of A/E lesions is mediated by genes located on the pathogenicity island locus of enterocyte effacement (LEE), which encode the adhesin intimin, a type III secretion system (T3SS) and six effectors, including the essential translocated intimin receptor (Tir). Seventeen additional effectors are encoded by genes located outside the LEE, in insertion elements and prophages. Here, using a stepwise approach, we generated an EPEC mutant lacking the entire effector genes (EPEC0) and intermediate mutants. We show that EPEC0 contains a functional T3SS. An EPEC mutant expressing intimin but lacking all the LEE effectors but Tir (EPEC1) was able to trigger robust actin polymerization in HeLa cells and mucin-producing intestinal LS174T cells. However, EPEC1 was unable to form A/E lesions on human intestinal in vitro organ cultures (IVOC). Screening the intermediate mutants for genes involved in A/E lesion formation on IVOC revealed that strains lacking non-LEE effector/s have a marginal ability to form A/E lesions. Furthermore, we found that Efa1/LifA proteins are important for A/E lesion formation efficiency in EPEC strains lacking multiple effectors. Taken together, these results demonstrate the intricate relationships between T3SS effectors and the essential role non-LEE effectors play in A/E lesion formation on mucosal surfaces.

  9. Attaching and effacing (A/E lesion formation by enteropathogenic E. coli on human intestinal mucosa is dependent on non-LEE effectors.

    Directory of Open Access Journals (Sweden)

    Massiel Cepeda-Molero

    2017-10-01

    Full Text Available Enteropathogenic E. coli (EPEC is a human pathogen that causes acute and chronic pediatric diarrhea. The hallmark of EPEC infection is the formation of attaching and effacing (A/E lesions in the intestinal epithelium. Formation of A/E lesions is mediated by genes located on the pathogenicity island locus of enterocyte effacement (LEE, which encode the adhesin intimin, a type III secretion system (T3SS and six effectors, including the essential translocated intimin receptor (Tir. Seventeen additional effectors are encoded by genes located outside the LEE, in insertion elements and prophages. Here, using a stepwise approach, we generated an EPEC mutant lacking the entire effector genes (EPEC0 and intermediate mutants. We show that EPEC0 contains a functional T3SS. An EPEC mutant expressing intimin but lacking all the LEE effectors but Tir (EPEC1 was able to trigger robust actin polymerization in HeLa cells and mucin-producing intestinal LS174T cells. However, EPEC1 was unable to form A/E lesions on human intestinal in vitro organ cultures (IVOC. Screening the intermediate mutants for genes involved in A/E lesion formation on IVOC revealed that strains lacking non-LEE effector/s have a marginal ability to form A/E lesions. Furthermore, we found that Efa1/LifA proteins are important for A/E lesion formation efficiency in EPEC strains lacking multiple effectors. Taken together, these results demonstrate the intricate relationships between T3SS effectors and the essential role non-LEE effectors play in A/E lesion formation on mucosal surfaces.

  10. LAP, an alcohol acetaldehyde dehydrogenase enzyme in Listeria, promotes bacterial adhesion to enterocyte-like Caco-2 cells only in pathogenic species.

    Science.gov (United States)

    Jagadeesan, Balamurugan; Koo, Ok Kyung; Kim, Kwang-Pyo; Burkholder, Kristin M; Mishra, Krishna K; Aroonnual, Amornrat; Bhunia, Arun K

    2010-09-01

    Listeria adhesion protein (LAP), an alcohol acetaldehyde dehydrogenase (lmo1634), interacts with host-cell receptor Hsp60 to promote bacterial adhesion during the intestinal phase of Listeria monocytogenes infection. The LAP homologue is present in pathogens (L. monocytogenes, L. ivanovii) and non-pathogens (L. innocua, L. welshimeri, L. seeligeri); however, its role in non-pathogens is unknown. Sequence analysis revealed 98 % amino acid similarity in LAP from all Listeria species. The N-terminus contains acetaldehyde dehydrogenase (ALDH) and the C-terminus an alcohol dehydrogenase (ADH). Recombinant LAP from L. monocytogenes, L. ivanovii, L. innocua and L. welshimeri exhibited ALDH and ADH activities, and displayed strong binding affinity (K(D) 2-31 nM) towards Hsp60. Flow cytometry, ELISA and immunoelectron microscopy revealed more surface-associated LAP in pathogens than non-pathogens. Pathogens exhibited significantly higher adhesion (Ppathogens; however, pretreatment of bacteria with Hsp60 caused 47-92 % reduction in adhesion only in pathogens. These data suggest that biochemical properties of LAP from pathogenic Listeria are similar to those of the protein from non-pathogens in many respects, such as substrate specificity, immunogenicity, and binding affinity to Hsp60. However, protein fractionation analysis of extracts from pathogenic and non-pathogenic Listeria species revealed that LAP was greatly reduced in intracellular and cell-surface protein fractions, and undetectable in the extracellular milieu of non-pathogens even though the lap transcript levels were similar for both. Furthermore, a LAP preparation from L. monocytogenes restored adhesion in a lap mutant (KB208) of L. monocytogenes but not in L. innocua, indicating possible lack of surface reassociation of LAP molecules in this bacterium. Taken together, these data suggest that LAP expression level, cell-surface localization, secretion and reassociation are responsible for LAP

  11. A family of indoles regulate virulence and Shiga toxin production in pathogenic E. coli.

    Directory of Open Access Journals (Sweden)

    Bettina Bommarius

    Full Text Available Enteropathogenic Escherichia coli (EPEC, enterohemorrhagic E. coli (EHEC and enteroaggregative E. coli (EAEC are intestinal pathogens that cause food and water-borne disease in humans. Using biochemical methods and NMR-based comparative metabolomics in conjunction with the nematode Caenorhabditis elegans, we developed a bioassay to identify secreted small molecules produced by these pathogens. We identified indole, indole-3-carboxaldehyde (ICA, and indole-3-acetic acid (IAA, as factors that only in combination are sufficient to kill C. elegans. Importantly, although lethal to C. elegans, these molecules downregulate several bacterial processes important for pathogenesis in mammals. These include motility, biofilm formation and production of Shiga toxins. Some pathogenic E. coli strains are known to contain a Locus of Enterocyte Effacement (LEE, which encodes virulence factors that cause "attaching and effacing" (A/E lesions in mammals, including formation of actin pedestals. We found that these indole derivatives also downregulate production of LEE virulence factors and inhibit pedestal formation on mammalian cells. Finally, upon oral administration, ICA inhibited virulence and promoted survival in a lethal mouse infection model. In summary, the C. elegans model in conjunction with metabolomics has facilitated identification of a family of indole derivatives that broadly regulate physiology in E. coli, and virulence in pathogenic strains. These molecules may enable development of new therapeutics that interfere with bacterial small-molecule signaling.

  12. Schizophrenia and the Virtues of Self-Effacement

    Directory of Open Access Journals (Sweden)

    Paul Barry

    2016-01-01

    Full Text Available Michael Stocker’s “The Schizophrenia of Modern Ethical Theories” attacks versions of consequentialism and deontological ethics on the grounds that they are self-effacing. While it is often thought that Stocker’s argument gives us a reason to favour virtue ethics over those other theories, Simon Keller has argued that this is a mistake. He claims that virtue ethics is also self-effacing, and is therefore afflicted with the self-effacement-related problems that Stocker identifies in consequentialism and deontology. This paper defends virtue ethics against this claim. Although there is a kind of self-effacement involved in the exercise of virtue, this is quite different from the so-called schizophrenia that Stocker thinks is induced by modern ethical theory. Importantly, manifesting virtue does not require one to embrace mutually inconsistent moral commitments, as is at times encouraged by consequentialists and deontologists. This paper also considers a reading of the virtue-ethical criterion of right action that is encouraged by Bernard Williams’s distinction between a de re and a de dicto interpretation of the phrase “acting as the virtuous person would.” I argue that such a reading addresses concerns that a virtue-ethical criterion of right action inevitably generates a problematic form of self-effacement.

  13. Locus of Adhesion and Autoaggregation (LAA), a pathogenicity island present in emerging Shiga Toxin-producing Escherichia coli strains.

    Science.gov (United States)

    Montero, David A; Velasco, Juliana; Del Canto, Felipe; Puente, Jose L; Padola, Nora L; Rasko, David A; Farfán, Mauricio; Salazar, Juan C; Vidal, Roberto

    2017-08-01

    Shiga Toxin-producing Escherichia coli (STEC) are a group of foodborne pathogens associated with diarrhea, dysentery, hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). Shiga toxins are the major virulence factor of these pathogens, however adhesion and colonization to the human intestine is required for STEC pathogenesis. A subset of STEC strains carry the Locus of Enterocyte Effacement (LEE) pathogenicity island (PAI), which encodes genes that mediate the colonization of the human intestine. While LEE-positive STEC strains have traditionally been associated with human disease, the burden of disease caused by STEC strains that lacks LEE (LEE-negative) has increased recently in several countries; however, in the absence of LEE, the molecular pathogenic mechanisms by STEC strains are unknown. Here we report a 86-kb mosaic PAI composed of four modules that encode 80 genes, including novel and known virulence factors associated with adherence and autoaggregation. Therefore, we named this PAI as Locus of Adhesion and Autoaggregation (LAA). Phylogenomic analysis using whole-genome sequences of STEC strains available in the NCBI database indicates that LAA PAI is exclusively present in a subset of emerging LEE-negative STEC strains, including strains isolated from HC and HUS cases. We suggest that the acquisition of this PAI is a recent evolutionary event, which may contribute to the emergence of these STEC.

  14. Attaching and effacing Escherichia coli isolates from Danish children: clinical significance and microbiological characteristics

    DEFF Research Database (Denmark)

    Jensen, C; Ethelberg, S; Olesen, B

    2007-01-01

    This study describes the prevalence, clinical manifestations and microbiological characteristics of attaching and effacing Escherichia coli isolates, i.e., enteropathogenic E. coli (EPEC) belonging to the classical EPEC serotypes, non-EPEC attaching and effacing E. coli (A/EEC) and verocytotoxin...

  15. Enterocyte protection - a new goal in ICU nutrition | Hodgson ...

    African Journals Online (AJOL)

    Enterocytes are among the most metabolically active cells in the body but are the least well supplied with blood even under resting conditions. Maintaining function of enterocytes has benefits that are becoming apparent in terms of improved outcomes from such diverse diseases as colorectal cancer and pneumonia.

  16. Escherichia coli type III secretion system 2 regulator EtrA promotes virulence of avian pathogenic Escherichia coli.

    Science.gov (United States)

    Wang, Shaohui; Xu, Xuan; Liu, Xin; Wang, Dong; Liang, Hua; Wu, Xiaojun; Tian, Mingxing; Ding, Chan; Wang, Guijun; Yu, Shengqing

    2017-10-01

    The Escherichia coli type III secretion system 2 (ETT2) is found in most E. coli strains, including pathogenic and commensal strains. Although many ETT2 gene clusters carry multiple genetic mutations or deletions, ETT2 is known to be involved in bacterial virulence. In enterohaemorrhagic E. coli (EHEC), ETT2 affects adhesion through the regulator EtrA, which regulates transcription and secretion of the type III secretion system (T3SS) encoded by the locus of enterocyte effacement (LEE). To date, no studies have been conducted on the role of EtrA in the virulence of avian pathogenic E. coli (APEC), which harbours only ETT2. Thus, we constructed etrA mutant and complemented strains of APEC and evaluated their phenotypes and pathogenicities. We found that the etrA gene deletion significantly reduced bacterial survival in macrophages, and proliferation and virulence in ducks. In addition, the etrA gene deletion reduced expression of the APEC fimbriae genes. Upregulation of genes encoding the pro-inflammatory cytokines interleukin (IL)-1β and IL-8 was also observed in HD-11 macrophages infected with the etrA gene mutant strain compared to the wild-type strain. Furthermore, the altered capacities of the mutant strain were restored by genetic complementation. Our observations demonstrate that the ETT2 regulator EtrA contributes to the virulence of APEC.

  17. Apical secretion of apolipoproteins from enterocytes

    DEFF Research Database (Denmark)

    Danielsen, E M; Hansen, Gert Helge; Poulsen, Mona Dam

    1993-01-01

    Synthesis and secretion of apolipoproteins in pig small intestine was studied by pulse-chase labeling of jejunal segments, kept in organ culture. Apo A-1 and apo B-48 were the two major proteins released, constituting 25 and 10%, respectively, of the total amount of labeled protein in the mucosal...... in the soluble fraction, suggesting a basolateral secretion into the intercellular space, and both this accumulation and the release to the medium was prevented by culture at 20 degrees C. The specific radioactivity of apo A-1 and apo B-48 released to the medium was significantly higher than...... that enterocytes release most of their newly made free apo A-1 and a significant portion of apo B-48 by exocytosis via the brush border membrane into the intestinal lumen. Fat absorption reduced apolipoprotein secretion to the medium and induced the formation of chylomicrons, containing apo A-1 at their surface...

  18. [Isolated enterocytes as an object of functional morphology].

    Science.gov (United States)

    Ugolev, A M; Tsibulevskiĭ, A Iu; Mamatakhunov, A I

    1995-01-01

    Morphological examination of isolated enterocytes obtained-from the rat jejunum initial region by mechanical method after the previous treatment with ethylendiamintetracetic acid disodium salt included staining with hematoxylin, carmin and janus green. Histochemical reaction to alcaline phosphatase, succinate dehydrogenase, lactate dehydrogenase, ATP-ase and glycosaminoglycans were performed. Significant resemblance between the main cytological and cytochemical characteristics of the isolated enterocytes and those of the intestinal epithelium was demonstrated. Morphophysiological examination of isolated enterocytes, incubated in media, containing different substrates (glucose, maltose, glycine, trioleine) and under effect of oxygenated and not-oxygenated media demonstrated that mitochondria intracellular topography and succinate dehydrogenase activity significantly depend on their functional state.

  19. Shiga toxin 1 interaction with enterocytes causes apical protein mistargeting through the depletion of intracellular galectin-3

    Energy Technology Data Exchange (ETDEWEB)

    Laiko, Marina; Murtazina, Rakhilya; Malyukova, Irina [Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States); Zhu, Chengru; Boedeker, Edgar C. [Department of Medicine, University of New Mexico School of Medicine, Albuquerque, NM 87131 (United States); Gutsal, Oksana [Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States); O' Malley, Robert; Cole, Robert N. [Department of Biochemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States); Tarr, Phillip I. [Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110 (United States); Murray, Karen F. [Department of Pediatrics, Children' s Hospital and Regional Medical Center, Seattle, WA 98105 (United States); Kane, Anne [The Tufts New England Medical Center, Boston, MA 02111 (United States); Donowitz, Mark [Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States); Kovbasnjuk, Olga, E-mail: okovbas1@jhmi.edu [Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205 (United States)

    2010-02-15

    Shiga toxins (Stx) 1 and 2 are responsible for intestinal and systemic sequelae of infection by enterohemorrhagic Escherichia coli (EHEC). However, the mechanisms through which enterocytes are damaged remain unclear. While secondary damage from ischemia and inflammation are postulated mechanisms for all intestinal effects, little evidence excludes roles for more primary toxin effects on intestinal epithelial cells. We now document direct pathologic effects of Stx on intestinal epithelial cells. We study a well-characterized rabbit model of EHEC infection, intestinal tissue and stool samples from EHEC-infected patients, and T84 intestinal epithelial cells treated with Stx1. Toxin uptake by intestinal epithelial cells in vitro and in vivo causes galectin-3 depletion from enterocytes by increasing the apical galectin-3 secretion. This Shiga toxin-mediated galectin-3 depletion impairs trafficking of several brush border structural proteins and transporters, including villin, dipeptidyl peptidase IV, and the sodium-proton exchanger 2, a major colonic sodium absorptive protein. The mistargeting of proteins responsible for the absorptive function might be a key event in Stx1-induced diarrhea. These observations provide new evidence that human enterocytes are directly damaged by Stx1. Conceivably, depletion of galectin-3 from enterocytes and subsequent apical protein mistargeting might even provide a means whereby other pathogens might alter intestinal epithelial absorption and produce diarrhea.

  20. Shiga toxin-converting phages and the emergence of new pathogenic Escherichia coli: a world in motion

    Science.gov (United States)

    Tozzoli, Rosangela; Grande, Laura; Michelacci, Valeria; Ranieri, Paola; Maugliani, Antonella; Caprioli, Alfredo; Morabito, Stefano

    2014-01-01

    Shiga toxin (Stx)-producing Escherichia coli (STEC) are pathogenic E. coli causing diarrhea, hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). STEC are characterized by a constellation of virulence factors additional to Stx and have long been regarded as capable to cause HC and HUS when possessing the ability of inducing the attaching and effacing (A/E) lesion to the enterocyte, although strains isolated from such severe infections sometimes lack this virulence feature. Interestingly, the capability to cause the A/E lesion is shared with another E. coli pathogroup, the Enteropathogenic E. coli (EPEC). In the very recent times, a different type of STEC broke the scene causing a shift in the paradigm for HUS-associated STEC. In 2011, a STEC O104:H4 caused a large outbreak with more than 800 HUS and 50 deaths. Such a strain presented the adhesion determinants of Enteroaggregative E. coli (EAggEC). We investigated the possibility that, besides STEC and EAggEC, other pathogenic E. coli could be susceptible to infection with stx-phages. A panel of stx2-phages obtained from STEC isolated from human disease was used to infect experimentally E. coli strains representing all the known pathogenic types, including both diarrheagenic E. coli (DEC) and extra-intestinal pathogenic E. coli (ExPEC). We observed that all the E. coli pathogroups used in the infection experiments were susceptible to the infection. Our results suggest that the stx2-phages used may not have specificity for E. coli adapted to the intestinal environment, at least in the conditions used. Additionally, we could only observe transient lysogens suggesting that the event of stable stx2-phage acquisition occurs rarely. PMID:24999453

  1. Enterocyte protection – a new goal in ICU nutrition

    African Journals Online (AJOL)

    2007-02-08

    Feb 8, 2007 ... such as the heart, kidneys and brain.5 Blood flow to the enterocytes is intended for absorption rather than delivery of nutrients so is sluggish even under .... such as dopamine and adrenaline, which promote splanchnic vasoconstriction. Attempting to feed a full dose of enteral nutrition via a nasojejunal tube.

  2. Enterocyte protection – a new goal in ICU nutrition

    African Journals Online (AJOL)

    2007-02-08

    Feb 8, 2007 ... function of enterocytes has benefits that are becoming apparent in terms of improved ... endotracheal tube or tracheostomy do not need to be ... 23, No. 1. SAJCC. 7. • Carbohydrates: reduce the catabolic response generated by starvation and surgery. Insulin sensitivity and tissue integrity are maintained.10.

  3. Minimal SPI1-T3SS effector requirement for Salmonella enterocyte invasion and intracellular proliferation in vivo.

    Science.gov (United States)

    Zhang, Kaiyi; Riba, Ambre; Nietschke, Monika; Torow, Natalia; Repnik, Urska; Pütz, Andreas; Fulde, Marcus; Dupont, Aline; Hensel, Michael; Hornef, Mathias

    2018-03-01

    Effector molecules translocated by the Salmonella pathogenicity island (SPI)1-encoded type 3 secretion system (T3SS) critically contribute to the pathogenesis of human Salmonella infection. They facilitate internalization by non-phagocytic enterocytes rendering the intestinal epithelium an entry site for infection. Their function in vivo has remained ill-defined due to the lack of a suitable animal model that allows visualization of intraepithelial Salmonella. Here, we took advantage of our novel neonatal mouse model and analyzed various bacterial mutants and reporter strains as well as gene deficient mice. Our results demonstrate the critical but redundant role of SopE2 and SipA for enterocyte invasion, prerequisite for transcriptional stimulation and mucosal translocation in vivo. In contrast, the generation of a replicative intraepithelial endosomal compartment required the cooperative action of SipA and SopE2 or SipA and SopB but was independent of SopA or host MyD88 signaling. Intraepithelial growth had no critical influence on systemic spread. Our results define the role of SPI1-T3SS effector molecules during enterocyte invasion and intraepithelial proliferation in vivo providing novel insight in the early course of Salmonella infection.

  4. Detection of attaching and effacing virulence gene of E. coli

    Directory of Open Access Journals (Sweden)

    Maratu Soleha

    2013-07-01

    Full Text Available AbstrakLatar belakang: Bakteri Escherichia coli (E. coli ada yang telah bermutasi menjadi patogen yang menimbulkan berbagai penyakit seperti hemorrhagic colitis (HC, hemolytic uremic syndrome (HUS, sepsis, pnemonia, neonatal meningitis, dan infeksi saluran kemih. Mutasi terjadi karena bakteri ini menerima transfer gen yang virulen dari bakteri lain yang hidup di sekitarnya. E. coli yang biasanya hidup normal di dalam usus manusia telah beradaptasi sehingga bisa hidup di tanah, makanan, dan saluran kemih. Penelitian ini mendeteksi gene yang virulen pada DNA isolat E. coli. Metode: Untuk deteksi E. coli yang virulen pada penelitian ini digunakan metode Real-time PCR dengan mencocokkan hasil sekuensing dengan sekuens E. coli virulen yang telah di publikasikan sebagai rujukan. Hasil: Sekuens RT PCR menggambarkan DNA gen eae pada BLAST mempunyai kesesuaian dengan rujukan segmen E. coli yang virulen. Dari sampel yang berasal dari E. coli di sekitar perairan lingkungan didapatkan gen Eae sebagai gen yang menyebabkan E. coli menjadi virulen sebesar 7,3%. Kesimpulan: E. coli yang virulen ditemukan pada sampel E. coli yang berasal dari perairan lingkungan dengan metode realtime PCR. (Health Science Indones 2013;1:41-6 Kata kunci: gen virulen E. coli, real-time PCR, perairan lingkunganAbstractBackground: Escherichia coli(E. coli bacteria have developed into pathogenic bacteria that caused diseases such as hemorrhagic colitis (HC, hemolytic uremic syndrome (HUS, sepsis, pneumonia, neonatal meningitis, and urinary tract infections. Pathogenic E. coli have acquired pathogenic/virulence genes from other bacteria in their environment. E. coli that normally lived in the human gut had adapted to other niches such as soil, food and the urinary tract. This study investigated the presence of pathogenic E. coli from water samples by examining E. coli virulence genes present in E. coli genomes of water sourced isolates. Methods:This study used Real-time PCR to detect

  5. Glucose transport by epithelia prepared from harvested enterocytes

    DEFF Research Database (Denmark)

    Kimura, Yasuhiro; van der Merwe, Marie; Bering, Stine Brandt

    2015-01-01

    of epithelial function and was demonstrated by cellular accumulation of tracer (14)C D-glucose and Ussing chamber based short-circuit currents. Assessment of the epithelia by light and immunofluorescent microscopy revealed the harvested enterocytes remain differentiated and establish cell-cell connections...... transporter SGLT-1. Similarly, accumulation of (14)C D-glucose by the epithelia was inhibited by phloridzin, but not phloretin, and was stimulated by pre-exposure to AMP and adenosine, apparently by a microtubule-based mechanism that is disrupted by nocodazole, with the magnitudes of responses to adenosine......, forskolin, and health status exceeding those we have measured using intact tissues. Our findings indicate that epithelia prepared from harvested enterocytes provide an alternative approach for comparative studies of the characteristics of nutrient transport by the upper villus epithelium and the responses...

  6. Bacterial effector NleL promotes enterohemorrhagic E. coli-induced attaching and effacing lesions by ubiquitylating and inactivating JNK.

    Science.gov (United States)

    Sheng, Xiangpeng; You, Qing; Zhu, Hongnian; Chang, ZeNan; Li, Qingrun; Wang, Haifeng; Wang, Chen; Wang, Hongyan; Hui, Lijian; Du, Chongtao; Xie, Xiaoduo; Zeng, Rong; Lin, Anning; Shi, Dongfang; Ruan, Kangcheng; Yan, Jinghua; Gao, George Fu; Shao, Feng; Hu, Ronggui

    2017-07-01

    As a major diarrheagenic human pathogen, enterohemorrhagic Escherichia coli (EHEC) produce attaching and effacing (A/E) lesions, characterized by the formation of actin pedestals, on mammalian cells. A bacterial T3SS effector NleL from EHEC O157:H7 was recently shown to be a HECT-like E3 ligase in vitro, but its biological functions and host targets remain elusive. Here, we report that NleL is required to effectively promote EHEC-induced A/E lesions and bacterial infection. Furthermore, human c-Jun NH2-terminal kinases (JNKs) were identified as primary substrates of NleL. NleL-induced JNK ubiquitylation, particularly mono-ubiquitylation at the Lys 68 residue of JNK, impairs JNK's interaction with an upstream kinase MKK7, thus disrupting JNK phosphorylation and activation. This subsequently suppresses the transcriptional activity of activator protein-1 (AP-1), which modulates the formation of the EHEC-induced actin pedestals. Moreover, JNK knockdown or inhibition in host cells complements NleL deficiency in EHEC infection. Thus, we demonstrate that the effector protein NleL enhances the ability of EHEC to infect host cells by targeting host JNK, and elucidate an inhibitory role of ubiquitylation in regulating JNK phosphorylation.

  7. Bacterial effector NleL promotes enterohemorrhagic E. coli-induced attaching and effacing lesions by ubiquitylating and inactivating JNK.

    Directory of Open Access Journals (Sweden)

    Xiangpeng Sheng

    2017-07-01

    Full Text Available As a major diarrheagenic human pathogen, enterohemorrhagic Escherichia coli (EHEC produce attaching and effacing (A/E lesions, characterized by the formation of actin pedestals, on mammalian cells. A bacterial T3SS effector NleL from EHEC O157:H7 was recently shown to be a HECT-like E3 ligase in vitro, but its biological functions and host targets remain elusive. Here, we report that NleL is required to effectively promote EHEC-induced A/E lesions and bacterial infection. Furthermore, human c-Jun NH2-terminal kinases (JNKs were identified as primary substrates of NleL. NleL-induced JNK ubiquitylation, particularly mono-ubiquitylation at the Lys 68 residue of JNK, impairs JNK's interaction with an upstream kinase MKK7, thus disrupting JNK phosphorylation and activation. This subsequently suppresses the transcriptional activity of activator protein-1 (AP-1, which modulates the formation of the EHEC-induced actin pedestals. Moreover, JNK knockdown or inhibition in host cells complements NleL deficiency in EHEC infection. Thus, we demonstrate that the effector protein NleL enhances the ability of EHEC to infect host cells by targeting host JNK, and elucidate an inhibitory role of ubiquitylation in regulating JNK phosphorylation.

  8. Attaching and effacing Escherichia coli isolates from Danish children: clinical significance and microbiological characteristics

    DEFF Research Database (Denmark)

    Jensen, C; Ethelberg, S; Olesen, B

    2007-01-01

    This study describes the prevalence, clinical manifestations and microbiological characteristics of attaching and effacing Escherichia coli isolates, i.e., enteropathogenic E. coli (EPEC) belonging to the classical EPEC serotypes, non-EPEC attaching and effacing E. coli (A/EEC) and verocytotoxin......-producing E. coli (VTEC), isolated in a case-control study of Danish children aged EPEC and VTEC were more prevalent in cases (2.4% and 2.6%, respectively) than in controls (0.7% and 0.7%, respectively). There was a high frequency of A....../EEC isolates (n = 121), but these were equally prevalent in cases (11.3%) and controls (12.5%), and comprised a heterogeneous distribution of O:H serotypes. The intimin (eae) subtypes in A/EEC isolates showed an even distribution; the eae-gamma subtype predominated in classical EPEC cases. The virulence genes...

  9. Structured illumination microscopy and automatized image processing as a rapid diagnostic tool for podocyte effacement.

    Science.gov (United States)

    Siegerist, Florian; Ribback, Silvia; Dombrowski, Frank; Amann, Kerstin; Zimmermann, Uwe; Endlich, Karlhans; Endlich, Nicole

    2017-09-13

    The morphology of podocyte foot processes is obligatory for renal function. Here we describe a method for the superresolution-visualization of podocyte foot processes using structured illumination microscopy of the slit diaphragm, which before has only been achieved by electron microscopy. As a proof of principle, we measured a mean foot process width of 0.249 ± 0.068 µm in healthy kidneys and a significant higher mean foot process width of 0.675 ± 0.256 µm in minimal change disease patients indicating effacement of foot processes. We then hypothesized that the slit length per glomerular capillary surface area (slit diaphragm density) could be used as an equivalent for the diagnosis of effacement. Using custom-made software we measured a mean value of 3.10 ± 0.27 µm -1 in healthy subjects and 1.83 ± 0.49 µm -1 in the minimal change disease patients. As foot process width was highly correlated with slit diaphragm density (R 2  = 0.91), we concluded that our approach is a valid method for the diagnosis of foot process effacement. In summary, we present a new technique to quantify podocyte damage, which combines superresolution microscopy with automatized image processing. Due to its diverse advantages, we propose this technique to be included into routine diagnostics of glomerular histopathology.

  10. Inhibition of Bifidobacterium Cell Wall 51.74 kDa Adhesin Isolated from Infants Feces Towards Adhesion of Enteric Phatogen E. coli on Enterocyte Balb/C Mice

    Directory of Open Access Journals (Sweden)

    I Sukrama

    2012-01-01

    Full Text Available Objectives: To determine 51.74 kDa adhesin of Bifidobacterium sp cell wall isolated from infants feces as an anti adhesion of E. coli on enterocyte mice. Methods: Randomized Posttest-Only Control Group Design was employed to investigate adherence ability of this adhesin towards E.coli adhesion on mice entherocyte. Results: In this research, it was obtained, that the 51.74 kDa adhesin cell wall of Bifidobacterium sp has an ability to inhibit adhesion of E. coli on mice enterocyte. The ability was increased as an increase of adhsein concentration. Conclusions: that can be drawn from this research is the finding of 51.74 kDa adhesin cell wall of Bifidobacterium sp isolated from infants feces that can inhibit adhseion of E. coli on mice enterocyte. Future work that can be carried out are further researches concerning whether these protein can be applied to inhibit adherence of other pathogen bacteria

  11. Increased enterocyte apoptosis and Fas-Fas ligand system in celiac disease.

    Science.gov (United States)

    Ciccocioppo, R; Di Sabatino, A; Parroni, R; Muzi, P; D'Alò, S; Ventura, T; Pistoia, M A; Cifone, M G; Corazza, G R

    2001-04-01

    Our aim was to evaluate whether increased enterocyte apoptosis was responsible for mucosal flattening in celiac disease (CD), and, since the mechanisms responsible for tissue injury in this condition are unknown, we studied the possibility that the Fas-Fas ligand (FasL) system may be involved. Endoscopic duodenal biopsy specimens from 12 patients with untreated and 12 with treated CD and 12 control subjects were evaluated for enterocyte apoptosis by the terminal deoxynucleotidyl transferase-mediated digoxigenin-deoxyuridine triphosphate nick-end labeling assay and for Fas and FasL expression by immunohistochemistry. A coculture of isolated enterocytes (targets) and purified lamina propria mononuclear cells (LPMCs) (effectors) was performed in the absence or presence of an antagonistic ZB4 anti-Fas antibody. We found a significant correlation between the degree of villous atrophy, morphometrically evaluated, and the level of enterocyte apoptosis, suggesting that mucosal flattening is a consequence of exaggerated epithelial cell death. Most celiac enterocytes express Fas, and LPMCs express FasL. The abolishment of enterocyte apoptosis observed in the presence of ZB4 antibody suggests that enterocytes are potential targets of lymphocyte infiltrate. These results directly demonstrate that FasL-mediated apoptosis is a major mechanism responsible for enterocyte death in CD.

  12. Development of a chicken enterocyte culture to study its functional physiology

    Science.gov (United States)

    We developed a method to culture chicken intestinal enterocytes, the cells that absorb and form protective barriers against enteric bacteria, to study their functional physiologies. Using intestinal villi, harvested from day old broiler chicks, the enterocytes were isolated by sequential digestion ...

  13. Effaced Enigmata.

    Science.gov (United States)

    Gillett, Grant

    2017-10-01

    Severe head injury or brain injury presents clinical neuroscientists with a unique challenge. Based on an objective assessment of cognitive and neurological function, it is sometimes hard to recognize our patients as members of our moral community (actually or potentially) but we treat them as if that were is the case, and, therefore, as if they need rescuing. Thus their existences as enigmata-beings who may or may not reveal themselves to us through social and personal function realized in conversations and relationships-are in doubt. However, the objective mode of assessing individuals and their mental functions needs to be bracketed here, as we reconnect with them and offer them our help in the restorative journey that they need to take. The journey has many tortuous paths comprising it, not the least of which is the existential question of whether the damaged human being with whom we are engaged actually can be restored to a meaningful life. A negative answer to that question can bring the whole process to an abrupt end. Neuroscience cannot answer some of these questions, as they are ethical. Is this a life worth living and are our commitments going to go the distance that must be traversed here. Therefore, this is an area where ethics take priority over neuroscience, and it is on our ethical response that everything else hinges. Understanding the light this throws on the nature of a human being takes us to the heart of the value of every human being and the nexus of mutuality that is the moral community.

  14. Adherence of yeast and filamentous forms of Candida albicans to cultured enterocytes.

    Science.gov (United States)

    Wiesner, Stephen M; Bendel, Catherine M; Hess, Donavon J; Erlandsen, Stanley L; Wells, Carol L

    2002-03-01

    Systemic candidiasis is a major cause of complicating infections in intensive care units. Morbidity and mortality are high, even in those who receive appropriate antifungal therapy. Because the intestinal tract is considered a major portal of entry for systemic candidiasis, experiments were designed to clarify the ability of yeast and filamentous forms, as well as the INT1 gene product, to influence adherence of Candida albicans to the intestinal epithelium. Controlled. University teaching hospital research laboratory. Mature Caco-2 and HT-29 cultured enterocytes. C. albicans INT1 mutant strains, defective in filament production, were used to observe the ultrastructural surface interactions of C. albicans with cultured intestinal epithelial cells, namely Caco-2 and HT-29 cells. These mutant strains also were used to quantify the effect of the INT1 gene product on C. albicans adherence (yeast and filamentous forms) to cultured enterocytes. Ultrastructural surface interactions of C. albicans with cultured enterocytes were observed with high resolution scanning electron microscopy. C. albicans adherence to cultured enterocytes was quantified by using a colorimetric enzyme-linked immunosorbent assay. Both yeast and filamentous forms of C. albicans appeared tightly adherent to the apical surface of cultured enterocytes, and INT1 appeared to have little, if any, effect on these ultrastructural surface interactions. The distal ends of C. albicans filaments appeared to mediate adherence to enterocyte apical microvilli, and thigmotropism (contact guidance) appeared to play a role in C. albicans adherence. The absence of functional INT1 was associated with decreased adherence of C. albicans yeast forms to cultured enterocytes. Although functional INT1 appeared to facilitate adherence of C. albicans yeast forms to cultured enterocytes, the role of INT1 in adherence of filamentous forms was unclear, and both yeast and filamentous forms could adhere to, and perhaps invade, the

  15. (EfFacing the Face of Nationalism: Wrestling Masks in Chicano and Mexican Performance Art

    Directory of Open Access Journals (Sweden)

    Robert Neustadt

    2001-06-01

    Full Text Available Masks serve as particularly effective props in contemporary Mexican and Chicano performance art because of a number of deeply rooted traditions in Mexican culture. This essay explores the mask as code of honor in Mexican culture, and foregrounds the manner in which a number of contemporary Mexican and Chicano artists and performers strategically employ wrestling masks to (efface the mask-like image of Mexican or U.S. nationalism. I apply the label "performance artist" broadly, to include musicians and political figures that integrate an exaggerated sense of theatricality into their performances. Following the early work of Roland Barthes, I read performances as "texts" in which the wrestling masks function as immediately recognizable signs . I argue that by masking their identity and alluding to popular mask traditions, Chicano and Mexican performance artists make visible, and interrogate, the national face(s of power.

  16. Molecular characterisation of non-absorptive and absorptive enterocytes in human small intestine

    DEFF Research Database (Denmark)

    Gassler, N; Newrzella, D; Böhm, C

    2006-01-01

    BACKGROUND AND AIMS: Perturbation of differentiation of the crypt-villus axis of the human small intestine is associated with several intestinal disorders of clinical importance. At present, differentiation of small intestinal enterocytes in the crypt-villus axis is not well characterised. SUBJECTS...... genes, and vesicle/transport related genes was found. CONCLUSION: Two types of enterocytes were dissected at the molecular level, the non-absorptive enterocyte located in the upper part of crypts and the absorptive enterocyte found in the middle of villi. These data improve our knowledge about...... the physiology of the crypt-villus architecture in human small intestine and provide new insights into pathophysiological phenomena, such as villus atrophy, which is clinically important....

  17. Giardia co-infection promotes the secretion of antimicrobial peptides beta-defensin 2 and trefoil factor 3 and attenuates attaching and effacing bacteria-induced intestinal disease.

    Science.gov (United States)

    Manko, Anna; Motta, Jean-Paul; Cotton, James A; Feener, Troy; Oyeyemi, Ayodele; Vallance, Bruce A; Wallace, John L; Buret, Andre G

    2017-01-01

    Our understanding of polymicrobial gastrointestinal infections and their effects on host biology remains incompletely understood. Giardia duodenalis is an ubiquitous intestinal protozoan parasite infecting animals and humans. Concomitant infections with Giardia and other gastrointestinal pathogens commonly occur. In countries with poor sanitation, Giardia infection has been associated with decreased incidence of diarrheal disease and fever, and reduced serum inflammatory markers release, via mechanisms that remain obscure. This study analyzed Giardia spp. co-infections with attaching and effacing (A/E) pathogens, and assessed whether and how the presence of Giardia modulates host responses to A/E enteropathogens, and alters intestinal disease outcome. In mice infected with the A/E pathogen Citrobacter rodentium, co-infection with Giardia muris significantly attenuated weight loss, macro- and microscopic signs of colitis, bacterial colonization and translocation, while concurrently enhancing the production and secretion of antimicrobial peptides (AMPs) mouse β-defensin 3 and trefoil factor 3 (TFF3). Co-infection of human intestinal epithelial cells (Caco-2) monolayers with G. duodenalis trophozoites and enteropathogenic Escherichia coli (EPEC) enhanced the production of the AMPs human β-defensin 2 (HBD-2) and TFF3; this effect was inhibited with treatment of G. duodenalis with cysteine protease inhibitors. Collectively, these results suggest that Giardia infections are capable of reducing enteropathogen-induced colitis while increasing production of host AMPs. Additional studies also demonstrated that Giardia was able to directly inhibit the growth of pathogenic bacteria. These results reveal novel mechanisms whereby Giardia may protect against gastrointestinal disease induced by a co-infecting A/E enteropathogen. Our findings shed new light on how microbial-microbial interactions in the gut may protect a host during concomitant infections.

  18. Permeabilization of enterocytes induced by absorption of dietary fat

    DEFF Research Database (Denmark)

    Danielsen, Erik Michael; Hansen, Gert H; Rasmussen, Karina

    2013-01-01

    Absorption of dietary fat in the small intestine involves epithelial exposure to potentially harmful molecules such as bile salts and free fatty acids. We used organ culture of porcine jejunal explants incubated with a pre-digested mixture of fat (plant oil), bile and pancreatin to mimick the phy...... membranes of immature crypt cells, lacking detergent-resistant lipid raft microdomains, are less resistant to the deleterious effects of bile salts and free fatty acids....... penetrated the epithelium and accumulated in the basal lamina and the lamina propria. LY was also seen in the paracellular space, whereas villus enterocytes were generally only weakly labeled except for small amounts taken up by apical endocytosis. In the crypts, however, fat absorption induced cell...... permeabilization with LY accumulating in the cytosol and nucleus. Morphologically, both apical and basolateral membranes appeared intact, indicating that the leakiness was caused by minor lesions in the membrane. Albeit to a lesser extent, bile alone was capable of permeabilizing crypt cells, implying...

  19. Global Regulator of Virulence A (GrvA) Coordinates Expression of Discrete Pathogenic Mechanisms in Enterohemorrhagic Escherichia coli through Interactions with GadW-GadE.

    Science.gov (United States)

    Morgan, Jason K; Carroll, Ronan K; Harro, Carly M; Vendura, Khoury W; Shaw, Lindsey N; Riordan, James T

    2016-02-01

    Global regulator of virulence A (GrvA) is a ToxR-family transcriptional regulator that activates locus of enterocyte effacement (LEE)-dependent adherence in enterohemorrhagic Escherichia coli (EHEC). LEE activation by GrvA requires the Rcs phosphorelay response regulator RcsB and is sensitive to physiologically relevant concentrations of bicarbonate, a known stimulant of virulence systems in intestinal pathogens. This study determines the genomic scale of GrvA-dependent regulation and uncovers details of the molecular mechanism underlying GrvA-dependent regulation of pathogenic mechanisms in EHEC. In a grvA-null background of EHEC strain TW14359, RNA sequencing analysis revealed the altered expression of over 700 genes, including the downregulation of LEE- and non-LEE-encoded effectors and the upregulation of genes for glutamate-dependent acid resistance (GDAR). Upregulation of GDAR genes corresponded with a marked increase in acid resistance. GrvA-dependent regulation of GDAR and the LEE required gadE, the central activator of GDAR genes and a direct repressor of the LEE. Control of gadE by GrvA was further determined to occur through downregulation of the gadE activator GadW. This interaction of GrvA with GadW-GadE represses the acid resistance phenotype, while it concomitantly activates the LEE-dependent adherence and secretion of immune subversion effectors. The results of this study significantly broaden the scope of GrvA-dependent regulation and its role in EHEC pathogenesis. Enterohemorrhagic Escherichia coli (EHEC) is an intestinal human pathogen causing acute hemorrhagic colitis and life-threatening hemolytic-uremic syndrome. For successful transmission and gut colonization, EHEC relies on the glutamate-dependent acid resistance (GDAR) system and a type III secretion apparatus, encoded on the LEE pathogenicity island. This study investigates the mechanism whereby the DNA-binding regulator GrvA coordinates activation of the LEE with repression of GDAR

  20. Long-term selenium deficiency increases the pathogenicity of a Citrobacter rodentium infection in mice

    Science.gov (United States)

    Citrobacter rodentium is a mouse pathogen that causes infectious colitis and shares characteristics with human enteropathogenic (EPEC) and enterohemorrhagic (EHEC) Escherichia coli, including the ability to cause attaching and effacing lesions in the colon, and serves as a useful model to study the ...

  1. Skull fracture with effacement of the superior sagittal sinus following drone impact: a case report.

    Science.gov (United States)

    Chung, Lawrance K; Cheung, Yuri; Lagman, Carlito; Au Yong, Nicholas; McBride, Duncan Q; Yang, Isaac

    2017-09-01

    The popularity of unmanned aerial vehicles, or drones, raises safety concerns as they become increasingly common for commercial, personal, and recreational use. Collisions between drones and people may result in serious injuries. A 13-year-old male presented with a comminuted depressed skull fracture causing effacement of the superior sagittal sinus secondary to a racing drone impact. The patient experienced a brief loss of consciousness and reported lower extremity numbness and weakness after the accident. Imaging studies revealed bone fragments crossing the superior sagittal sinus with a short, focal segment of blood flow interruption. Neurosurgical intervention was deferred given the patient's improving neurological deficits, and the patient was treated conservatively. He was discharged home in stable condition. Drones may represent a hazard when operated inappropriately due to their capacity to fly at high speeds and altitudes. Impacts from drones can carry enough force to cause skull fractures and significant head injuries. The rising popularity of drones likely translates to an increased incidence of drone-related injuries. Thus, clinicians should be aware of this growing trend.

  2. NsrR, GadE, and GadX interplay in repressing expression of the Escherichia coli O157:H7 LEE pathogenicity island in response to nitric oxide.

    Directory of Open Access Journals (Sweden)

    Priscilla Branchu

    2014-01-01

    Full Text Available Expression of genes of the locus of enterocyte effacement (LEE is essential for adherence of enterohemorrhagic Escherichia coli (EHEC to intestinal epithelial cells. Gut factors that may modulate LEE gene expression may therefore influence the outcome of the infection. Because nitric oxide (NO is a critical effector of the intestinal immune response that may induce transcriptional regulation in enterobacteria, we investigated its influence on LEE expression in EHEC O157:H7. We demonstrate that NO inhibits the expression of genes belonging to LEE1, LEE4, and LEE5 operons, and that the NO sensor nitrite-sensitive repressor (NsrR is a positive regulator of these operons by interacting directly with the RNA polymerase complex. In the presence of NO, NsrR detaches from the LEE1/4/5 promoter regions and does not activate transcription. In parallel, two regulators of the acid resistance pathway, GadE and GadX, are induced by NO through an indirect NsrR-dependent mechanism. In this context, we show that the NO-dependent LEE1 down-regulation is due to absence of NsrR-mediated activation and to the repressor effect of GadX. Moreover, the inhibition of expression of LEE4 and LEE5 by NO is due to loss of NsrR-mediated activation, to LEE1 down-regulation and to GadE up-regulation. Lastly, we establish that chemical or cellular sources of NO inhibit the adherence of EHEC to human intestinal epithelial cells. These results highlight the critical effect of NsrR in the regulation of the LEE pathogenicity island and the potential role of NO in the limitation of colonization by EHEC.

  3. Immunomicroscopic localization of aminopeptidase N in the pig enterocyte. Implications for the route of intracellular transport

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Sjöström, H; Norén, Ove

    1987-01-01

    The subcellular localization of aminopeptidase N (EC 3.4.11.2) in the pig enterocyte was investigated by immunofluorescence and immunoelectron microscopy (immunogold staining). By indirect immunofluorescence on either frozen or paraffin-embedded sections, a very intense staining in the microvilla...

  4. Intestinal alkaline phosphatase: selective endocytosis from the enterocyte brush border during fat absorption

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Niels-Christiansen, Lise-Lotte; Immerdal, Lissi

    2007-01-01

    Absorption of dietary fat in the small intestine is accompanied by a rise of intestinal alkaline phosphatase (IAP) in the serum and of secretion of IAP-containing surfactant-like particles from the enterocytes. In the present work, fat absorption was studied in organ cultured mouse intestinal exp...

  5. Cholera toxin entry into pig enterocytes occurs via a lipid raft- and clathrin-dependent mechanism

    DEFF Research Database (Denmark)

    Hansen, Gert H; Dalskov, Stine-Mathilde; Rasmussen, Christina Rehné

    2005-01-01

    The small intestinal brush border is composed of lipid raft microdomains, but little is known about their role in the mechanism whereby cholera toxin gains entry into the enterocyte. The present work characterized the binding of cholera toxin B subunit (CTB) to the brush border and its...

  6. Blockade of cholesterol absorption by ezetimibe reveals a complex homeostatic network in enterocytes[S

    Science.gov (United States)

    Engelking, Luke J.; McFarlane, Matthew R.; Li, Christina K.; Liang, Guosheng

    2012-01-01

    Enterocyte cholesterol homeostasis reflects aggregated rates of sterol synthesis, efflux, and uptake from plasma and gut lumen. Cholesterol synthesis and LDL uptake are coordinately regulated by sterol regulatory element-binding proteins (SREBP), whereas sterol efflux is regulated by liver X receptors (LXR). How these processes are coordinately regulated in enterocytes, the site of cholesterol absorption, is not well understood. Here, we treat mice with ezetimibe to investigate the effect of blocking cholesterol absorption on intestinal SREBPs, LXRs, and their effectors. Ezetimibe increased nuclear SREBP-2 8-fold. HMG-CoA reductase (HMGR) and LDL receptor (LDLR) mRNA levels increased less than 3-fold, whereas their protein levels increased 30- and 10-fold, respectively. Expression of inducible degrader of LDLR (IDOL), an LXR-regulated gene that degrades LDLRs, was reduced 50% by ezetimibe. Coadministration of ezetimibe with the LXR agonist T0901317 abolished the reduction in IDOL and prevented the increase in LDLR protein. Ezetimibe-stimulated LDLR expression was independent of proprotein convertase subtilisin/kexin type 9 (PSCK9), a protein that degrades LDLRs. To maintain cholesterol homeostasis in the face of ezetimibe, enterocytes boost LDL uptake by increasing LDLR number, and they boost sterol synthesis by increasing HMGR and other cholesterologenic genes. These studies reveal a hitherto undescribed homeostatic network in enterocytes triggered by blockade of cholesterol absorption. PMID:22523394

  7. Propofol Does Not Reduce Pyroptosis of Enterocytes and Intestinal Epithelial Injury After Lipopolysaccharide Challenge.

    Science.gov (United States)

    Zhang, Xu-Yu; Chen, Xi; Zhang, Hu-Fei; Guan, Su; Wen, Shi-Hong; Huang, Wen-Qi; Liu, Zi-Meng

    2018-01-01

    To date, mechanisms of sepsis-induced intestinal epithelial injury are not well known. P2X7 receptor (P2X7R) regulates pyroptosis of lymphocytes, and propofol is usually used for sedation in septic patients. We aimed to determine the occurrence of enterocyte pyroptosis mediated by P2X7R and to explore the effects of propofol on pyroptosis and intestinal epithelial injury after lipopolysaccharide (LPS) challenge. A novel regimen of LPS challenge was applied in vitro and in vivo. Inhibitors of P2X7R (A438079) and NLRP3 inflammasome (MCC950), and different doses of propofol were administered. The caspase-1 expression, caspase-3 expression, caspase-11 expression, P2X7R expression and NLRP3 expression, extracellular ATP concentration and YO-PRO-1 uptake, and cytotoxicity and HMGB1 concentration were detected to evaluate enterocyte pyroptosis in cultured cells and intestinal epithelial tissues. Chiu's score, diamine oxidase and villus length were used to evaluate intestinal epithelial injury. Moreover, survival analysis was performed. LPS challenge activated caspase-11 expression and P2X7R expression, enhanced ATP concentration and YO-PRO-1 uptake, and led to increased cytotoxicity and HMGB1 concentration. Subsequently, LPS resulted in intestinal epithelial damage, as evidenced by increased levels of Chiu's score and diamine oxidase, and shorter villus length and high mortality of animals. A438079, but not MCC950, significantly relieved LPS-induced enterocyte pyroptosis and intestinal epithelial injury. Importantly, propofol did not confer the protective effects on enterocyte pyroptosis and intestinal epithelia although it markedly decreased P2X7R expression. LPS attack leads to activation of caspase-11/P2X7R and pyroptosis of enterocytes. Propofol does not reduce LPS-induced pyroptosis and intestinal epithelial injury, although it inhibits P2X7R upregulation.

  8. Systematic Identification and Sequence Analysis of the Genomic Islands of the Enteropathogenic Escherichia coli Strain B171-8 by the Combined Use of Whole-Genome PCR Scanning and Fosmid Mapping▿ †

    OpenAIRE

    Ogura, Yoshitoshi; Abe, Hiroyuki; Katsura, Keisuke; Kurokawa, Ken; Asadulghani, Md; Iguchi, Atsushi; Ooka, Tadasuke; Nakayama, Keisuke; Yamashita, Atsushi; Hattori, Masahira; Tobe, Toru; Hayashi, Tetsuya

    2008-01-01

    Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) are diarrheagenic pathogens that colonize the intestinal tract through the formation of attaching and effacing lesions, induced by effectors translocated via a type III secretion system (T3SS) encoded on the locus of enterocyte effacement (LEE). In EHEC O157, numerous virulence factors, including around 40 T3SS effectors, have been identified. Most of them are encoded on genomic islands (GEIs) such as prophages and ...

  9. Transcytosis of immunoglobulin A in the mouse enterocyte occurs through glycolipid raft- and rab17-containing compartments

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Niels-Christiansen, L L; Immerdal, Lissi

    1999-01-01

    BACKGROUND & AIMS: Glycolipid "rafts" have been shown to play a role in apical membrane trafficking in the enterocyte. The present study characterized the membrane compartments of the enterocyte involved in transepithelial transport of small intestinal immunoglobulin A (IgA). Methods: Immunogold...... electron microscopy and radioactive labeling of mouse small intestinal explants were performed. RESULTS: IgA and the polymeric immunoglobulin receptor/secretory component were present in a raft compartment. Raft association occurred posttranslationally within 30 minutes, preceding secretion...

  10. Mucolipin co-deficiency causes accelerated endolysosomal vacuolation of enterocytes and failure-to-thrive from birth to weaning.

    Directory of Open Access Journals (Sweden)

    Natalie N Remis

    2014-12-01

    Full Text Available During the suckling period, intestinal enterocytes are richly endowed with endosomes and lysosomes, which they presumably utilize for the uptake and intracellular digestion of milk proteins. By weaning, mature intestinal enterocytes replace those rich in lysosomes. We found that mouse enterocytes before weaning express high levels of two endolysosomal cation channels, mucolipins 3 and 1 -products of Trpml3 and Trpml1 genes; moreover neonatal enterocytes of mice lacking both mucolipins (Trpml3-/-;Trpml1-/- vacuolated pathologically within hours of birth and remained so until weaning. Ultrastructurally and chemically these fast-forming vacuoles resembled those that systemically appear in epithelial cells of mucolipidosis type IV (MLIV patients, which bear mutations in Trpml1. Hence, lack of both mucolipins 1 and 3 causes an accelerated MLIV-type of vacuolation in enterocytes. The vacuoles were aberrant hybrid organelles with both endosomal and lysosomal components, and were not generated by alterations in endocytosis or exocytosis, but likely by an imbalance between fusion of lysosomes and endosomes and their subsequent scission. However, upon extensive vacuolation enterocytes displayed reduced endocytosis from the intestinal lumen, a defect expected to compromise nutrient uptake. Mice lacking both mucolipins suffered a growth delay that began after birth and continued through the suckling period but recovered after weaning, coinciding with the developmental period of enterocyte vacuolation. Our results demonstrate genetic redundancy between lysosomal mucolipins 3 and 1 in neonatal enterocytes. Furthermore, our Trpml3-/-;Trpml1-/- mice represent a polygenic animal model of the poorly-understood, and often intractable, neonatal failure-to-thrive with intestinal pathology. Our results implicate lysosomes in neonatal intestinal pathologies, a major cause of infant mortality worldwide, and suggest transient intestinal dysfunction might affect newborns

  11. Lxr-driven enterocyte lipid droplet formation delays transport of ingested lipids[S

    OpenAIRE

    Cruz-Garcia, Lourdes; Schlegel, Amnon

    2014-01-01

    Liver X receptors (Lxrs) are master regulators of cholesterol catabolism, driving the elimination of cholesterol from the periphery to the lumen of the intestine. Development of pharmacological agents to activate Lxrs has been hindered by synthetic Lxr agonists’ induction of hepatic lipogenesis and hypertriglyceridemia. Elucidating the function of Lxrs in regulating enterocyte lipid handling might identify novel aspects of lipid metabolism that are pharmacologically amenable. We took a geneti...

  12. Absorption of Vitamin A and Carotenoids by the Enterocyte: Focus on Transport Proteins

    Directory of Open Access Journals (Sweden)

    Emmanuelle Reboul

    2013-09-01

    Full Text Available Vitamin A deficiency is a public health problem in most developing countries, especially in children and pregnant women. It is thus a priority in health policy to improve preformed vitamin A and/or provitamin A carotenoid status in these individuals. A more accurate understanding of the molecular mechanisms of intestinal vitamin A absorption is a key step in this direction. It was long thought that β-carotene (the main provitamin A carotenoid in human diet, and thus all carotenoids, were absorbed by a passive diffusion process, and that preformed vitamin A (retinol absorption occurred via an unidentified energy-dependent transporter. The discovery of proteins able to facilitate carotenoid uptake and secretion by the enterocyte during the past decade has challenged established assumptions, and the elucidation of the mechanisms of retinol intestinal absorption is in progress. After an overview of vitamin A and carotenoid fate during gastro-duodenal digestion, our focus will be directed to the putative or identified proteins participating in the intestinal membrane and cellular transport of vitamin A and carotenoids across the enterocyte (i.e., Scavenger Receptors or Cellular Retinol Binding Proteins, among others. Further progress in the identification of the proteins involved in intestinal transport of vitamin A and carotenoids across the enterocyte is of major importance for optimizing their bioavailability.

  13. Endoplasmic Reticulum Lipid Flux Influences Enterocyte Nuclear Morphology and Lipid-dependent Transcriptional Responses.

    Science.gov (United States)

    Zeituni, Erin M; Wilson, Meredith H; Zheng, Xiaobin; Iglesias, Pablo A; Sepanski, Michael A; Siddiqi, Mahmud A; Anderson, Jennifer L; Zheng, Yixian; Farber, Steven A

    2016-11-04

    Responding to a high-fat meal requires an interplay between multiple digestive tissues, sympathetic response pathways, and the gut microbiome. The epithelial enterocytes of the intestine are responsible for absorbing dietary nutrients and preparing them for circulation to distal tissues, which requires significant changes in cellular activity, including both morphological and transcriptional responses. Following a high-fat meal, we observe morphological changes in the enterocytes of larval zebrafish, including elongation of mitochondria, formation and expansion of lipid droplets, and the rapid and transient ruffling of the nuclear periphery. Dietary and pharmacological manipulation of zebrafish larvae demonstrated that these subcellular changes are specific to triglyceride absorption. The transcriptional changes that occur simultaneously with these morphological changes were determined using RNA sequencing, revealing a cohort of up-regulated genes associated with lipid droplet formation and lipid transport via lipoprotein particles. Using a microsomal triglyceride transfer protein (MTP) inhibitor to block β-lipoprotein particle formation, we demonstrate that the transcriptional response to a high-fat meal is associated with the transfer of ER triglyceride to nascent β-lipoproteins, possibly through the activation of Creb3l3/cyclic AMP-responsive element-binding protein. These data suggest that a transient increase in ER lipids is the likely mediator of the initial physiological response of intestinal enterocytes to dietary lipid. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Endoplasmic Reticulum Lipid Flux Influences Enterocyte Nuclear Morphology and Lipid-dependent Transcriptional Responses*

    Science.gov (United States)

    Zeituni, Erin M.; Wilson, Meredith H.; Zheng, Xiaobin; Iglesias, Pablo A.; Sepanski, Michael A.; Siddiqi, Mahmud A.; Anderson, Jennifer L.; Zheng, Yixian; Farber, Steven A.

    2016-01-01

    Responding to a high-fat meal requires an interplay between multiple digestive tissues, sympathetic response pathways, and the gut microbiome. The epithelial enterocytes of the intestine are responsible for absorbing dietary nutrients and preparing them for circulation to distal tissues, which requires significant changes in cellular activity, including both morphological and transcriptional responses. Following a high-fat meal, we observe morphological changes in the enterocytes of larval zebrafish, including elongation of mitochondria, formation and expansion of lipid droplets, and the rapid and transient ruffling of the nuclear periphery. Dietary and pharmacological manipulation of zebrafish larvae demonstrated that these subcellular changes are specific to triglyceride absorption. The transcriptional changes that occur simultaneously with these morphological changes were determined using RNA sequencing, revealing a cohort of up-regulated genes associated with lipid droplet formation and lipid transport via lipoprotein particles. Using a microsomal triglyceride transfer protein (MTP) inhibitor to block β-lipoprotein particle formation, we demonstrate that the transcriptional response to a high-fat meal is associated with the transfer of ER triglyceride to nascent β-lipoproteins, possibly through the activation of Creb3l3/cyclic AMP-responsive element-binding protein. These data suggest that a transient increase in ER lipids is the likely mediator of the initial physiological response of intestinal enterocytes to dietary lipid. PMID:27655916

  15. Direct effects of fermented cow's milk product with Lactobacillus paracasei CBA L74 on human enterocytes.

    Science.gov (United States)

    Paparo, L; Aitoro, R; Nocerino, R; Fierro, C; Bruno, C; Canani, R Berni

    2018-01-29

    Cow's milk fermented with Lactobacillus paracasei CBA L74 (FM-CBAL74) exerts a preventive effect against infectious diseases in children. We evaluated if this effect is at least in part related to a direct modulation of non-immune and immune defence mechanisms in human enterocytes. Human enterocytes (Caco-2) were stimulated for 48 h with FM-CBAL74 at different concentrations. Cell growth was assessed by colorimetric assay; cell differentiation (assessed by lactase expression), tight junction proteins (zonula occludens1 and occludin), mucin 2, and toll-like receptor (TRL) pathways were analysed by real-time PCR; innate immunity peptide synthesis, beta-defensin-2 (HBD-2) and cathelicidin (LL-37) were evaluated by ELISA. Mucus layer thickness was analysed by histochemistry. FMCBA L74 stimulated cell growth and differentiation, tight junction proteins and mucin 2 expression, and mucus layer thickness in a dose-dependent fashion. A significant stimulation of HBD-2 and LL-37 synthesis, associated with a modulation of TLR pathway, was also observed. FM-CBAL74 regulates non-immune and immune defence mechanisms through a direct interaction with the enterocytes. These effects could be involved in the preventive action against infectious diseases demonstrated by this fermented product in children.

  16. Which Self-Presentation Style Is More Effective? A Comparison of Instructors' Self-Enhancing and Self-Effacing Styles across the Culture

    Science.gov (United States)

    Kim, Eun Joo; Berger, Charles; Kim, Joohan; Kim, Min-Sun

    2014-01-01

    Many studies have investigated how people perceive others' self-presentation styles (such as enhancement and effacement) in forming first impressions and how culture influences the process. Most of those studies have, however, investigated self-presentation styles in the context of informal and intimate interpersonal relations. Few studies have…

  17. Enterocyte-specific epidermal growth factor prevents barrier dysfunction and improves mortality in murine peritonitis.

    Science.gov (United States)

    Clark, Jessica A; Gan, Heng; Samocha, Alexandr J; Fox, Amy C; Buchman, Timothy G; Coopersmith, Craig M

    2009-09-01

    Systemic administration of epidermal growth factor (EGF) decreases mortality in a murine model of septic peritonitis. Although EGF can have direct healing effects on the intestinal mucosa, it is unknown whether the benefits of systemic EGF in peritonitis are mediated through the intestine. Here, we demonstrate that enterocyte-specific overexpression of EGF is sufficient to prevent intestinal barrier dysfunction and improve survival in peritonitis. Transgenic FVB/N mice that overexpress EGF exclusively in enterocytes (IFABP-EGF) and wild-type (WT) mice were subjected to either sham laparotomy or cecal ligation and puncture (CLP). Intestinal permeability, expression of the tight junction proteins claudins-1, -2, -3, -4, -5, -7, and -8, occludin, and zonula occludens-1; villus length; intestinal epithelial proliferation; and epithelial apoptosis were evaluated. A separate cohort of mice was followed for survival. Peritonitis induced a threefold increase in intestinal permeability in WT mice. This was associated with increased claudin-2 expression and a change in subcellular localization. Permeability decreased to basal levels in IFABP-EGF septic mice, and claudin-2 expression and localization were similar to those of sham animals. Claudin-4 expression was decreased following CLP but was not different between WT septic mice and IFABP-EGF septic mice. Peritonitis-induced decreases in villus length and proliferation and increases in apoptosis seen in WT septic mice did not occur in IFABP-EGF septic mice. IFABP-EGF mice had improved 7-day mortality compared with WT septic mice (6% vs. 64%). Since enterocyte-specific overexpression of EGF is sufficient to prevent peritonitis-induced intestinal barrier dysfunction and confers a survival advantage, the protective effects of systemic EGF in septic peritonitis appear to be mediated in an intestine-specific fashion.

  18. Probing endocytosis from the enterocyte brush border using fluorescent lipophilic dyes

    DEFF Research Database (Denmark)

    Danielsen, E Michael

    2015-01-01

    The small intestinal brush border is a specialized cell membrane that needs to withstand the solubilizing effect of bile salts during assimilation of dietary nutrients and to achieve detergent resistance; it is highly enriched in glycolipids organized in lipid raft microdomains. In the present work......-toluenesulfonate), and CellMask Orange plasma membrane stain were used to study endocytosis from the enterocyte brush border of organ-cultured porcine mucosal explants. All the dyes readily incorporated into the brush border but were not detectably endocytosed by 5 min, indicating a slow uptake compared with other cell types...

  19. Enterocyte Damage: A Piece in the Puzzle of Post-Cardiac Arrest Syndrome.

    Science.gov (United States)

    Piton, Gaël; Belin, Nicolas; Barrot, Loïc; Belon, François; Cypriani, Benoit; Navellou, Jean-Christophe; Capellier, Gilles

    2015-11-01

    Cardiac arrest is considered to be a cause of small bowel ischemia, but the consequences of cardiac arrest on the human small bowel have been rarely studied. Plasma citrulline concentration is a marker of functional enterocyte mass, and plasma intestinal fatty acid-binding protein (I-FABP) concentration is a marker of enterocyte damage. We aimed to measure enterocyte biomarkers after cardiac arrest and to study the prognostic value of biomarker abnormalities. This is a prospective, observational, single-center study of patients admitted to the intensive care unit (ICU) for cardiac arrest, evaluating plasma citrulline and I-FABP concentrations at admission and after 24  h and variables according to the Utstein criteria. Variables according to 28-day Cerebral Performance Category score of 1 to 2 (good neurological outcome) versus 3 to 5 (poor neurological outcome) were compared. Sixty-nine patients with cardiac arrest of both cardiac and hypoxic origin were included. At ICU admission, plasma citrulline concentration was low in 65% and plasma I-FABP was elevated in 82% of the patients. After 24  h, plasma citrulline was low in 82% and I-FABP was normal in 60% of the patients. Patients with a poor neurological outcome had a lower plasma citrulline concentration and a higher I-FABP concentration at ICU admission. By multivariate analysis, plasma citrulline levels of 13.1  μmol L or less and I-FABP more than 260  pg mL were independently associated with a poor neurological outcome (odds ratio, 21.9 [2.2-215], and odds ratio, 13.6 [1.4-129], respectively). Cardiac arrest resuscitation is associated with evidence of small bowel mucosal damage in most patients, with a short and intense I-FABP elevation at admission and a decrease in citrulline concentration during the first day. In this study, low plasma citrulline and high I-FABP concentrations at ICU admission were predictive of a poor neurological outcome. This study confirms that cardiac arrest is a model of

  20. Altered gene expression in highly purified enterocytes from patients with active coeliac disease

    Directory of Open Access Journals (Sweden)

    Jackson John

    2008-08-01

    Full Text Available Abstract Background Coeliac disease is a multifactorial inflammatory disorder of the intestine caused by ingestion of gluten in genetically susceptible individuals. Genes within the HLA-DQ locus are considered to contribute some 40% of the genetic influence on this disease. However, information on other disease causing genes is sparse. Since enterocytes are considered to play a central role in coeliac pathology, the aim of this study was to examine gene expression in a highly purified isolate of these cells taken from patients with active disease. Epithelial cells were isolated from duodenal biopsies taken from five coeliac patients with active disease and five non-coeliac control subjects. Contaminating T cells were removed by magnetic sorting. The gene expression profile of the cells was examined using microarray analysis. Validation of significantly altered genes was performed by real-time RT-PCR and immunohistochemistry. Results Enterocyte suspensions of high purity (98–99% were isolated from intestinal biopsies. Of the 3,800 genes investigated, 102 genes were found to have significantly altered expression between coeliac disease patients and controls (p Conclusion This study provides a profile of the molecular changes that occur in the intestinal epithelium of coeliac patients with active disease. Novel candidate genes were revealed which highlight the contribution of the epithelial cell to the pathogenesis of coeliac disease.

  1. Early effects of gliadin on enterocyte intracellular signalling involved in intestinal barrier function.

    Science.gov (United States)

    Clemente, M G; De Virgiliis, S; Kang, J S; Macatagney, R; Musu, M P; Di Pierro, M R; Drago, S; Congia, M; Fasano, A

    2003-02-01

    Despite the progress made in understanding the immunological aspects of the pathogenesis of coeliac disease (CD), the early steps that allow gliadin to cross the intestinal barrier are still largely unknown. The aim of this study was to establish whether gliadin activates a zonulin dependent enterocyte intracellular signalling pathway(s) leading to increased intestinal permeability. The effect of gliadin on the enterocyte actin cytoskeleton was studied on rat intestinal epithelial (IEC-6) cell cultures by fluorescence microscopy and spectrofluorimetry. Zonulin concentration was measured on cell culture supernatants by enzyme linked immunosorbent assay. Transepithelial intestinal resistance (Rt) was measured on ex vivo intestinal tissues mounted in Ussing chambers. Incubation of cells with gliadin led to a reversible protein kinase C (PKC) mediated actin polymerisation temporarily coincident with zonulin release. A significant reduction in Rt was observed after gliadin addition on rabbit intestinal mucosa mounted in Ussing chambers. Pretreatment with the zonulin inhibitor FZI/0 abolished the gliadin induced actin polymerisation and Rt reduction but not zonulin release. Gliadin induces zonulin release in intestinal epithelial cells in vitro. Activation of the zonulin pathway by PKC mediated cytoskeleton reorganisation and tight junction opening leads to a rapid increase in intestinal permeability.

  2. Mucolipin Co-deficiency Causes Accelerated Endolysosomal Vacuolation of Enterocytes and Failure-to-Thrive from Birth to Weaning

    Science.gov (United States)

    Castiglioni, Andrew J.; Flores, Emma N.; Cantú, Jorge A.; García-Añoveros, Jaime

    2014-01-01

    During the suckling period, intestinal enterocytes are richly endowed with endosomes and lysosomes, which they presumably utilize for the uptake and intracellular digestion of milk proteins. By weaning, mature intestinal enterocytes replace those rich in lysosomes. We found that mouse enterocytes before weaning express high levels of two endolysosomal cation channels, mucolipins 3 and 1 -products of Trpml3 and Trpml1 genes; moreover neonatal enterocytes of mice lacking both mucolipins (Trpml3−/−;Trpml1−/−) vacuolated pathologically within hours of birth and remained so until weaning. Ultrastructurally and chemically these fast-forming vacuoles resembled those that systemically appear in epithelial cells of mucolipidosis type IV (MLIV) patients, which bear mutations in Trpml1. Hence, lack of both mucolipins 1 and 3 causes an accelerated MLIV-type of vacuolation in enterocytes. The vacuoles were aberrant hybrid organelles with both endosomal and lysosomal components, and were not generated by alterations in endocytosis or exocytosis, but likely by an imbalance between fusion of lysosomes and endosomes and their subsequent scission. However, upon extensive vacuolation enterocytes displayed reduced endocytosis from the intestinal lumen, a defect expected to compromise nutrient uptake. Mice lacking both mucolipins suffered a growth delay that began after birth and continued through the suckling period but recovered after weaning, coinciding with the developmental period of enterocyte vacuolation. Our results demonstrate genetic redundancy between lysosomal mucolipins 3 and 1 in neonatal enterocytes. Furthermore, our Trpml3−/−;Trpml1−/− mice represent a polygenic animal model of the poorly-understood, and often intractable, neonatal failure-to-thrive with intestinal pathology. Our results implicate lysosomes in neonatal intestinal pathologies, a major cause of infant mortality worldwide, and suggest transient intestinal dysfunction might affect newborns

  3. Lipid rafts exist as stable cholesterol-independent microdomains in the brush border membrane of enterocytes

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Immerdal, Lissi; Thorsen, Evy

    2001-01-01

    Glycosphingolipid/cholesterol-rich membranes ("rafts")can be isolated from many types of cells, but their existence as stable microdomains in the cell membrane has been elusive. Addressing this problem, we studied the distribution of galectin-4, a raft marker, and lactase, a protein excluded from...... rafts, on microvillar vesicles from the enterocyte brush border membrane. Magnetic beads coated with either anti-galectin-4 or anti-lactase antibodies were used for immunoisolation of vesicles followed by double immunogold labeling of the two proteins. A morphometric analysis revealed subpopulations...... of raft-rich and raft-poor vesicles by the following criteria: 1) the lactase/galectin-4 labeling ratio/vesicle captured by the anti-lactase beads was significantly higher (p

  4. Arginine does not exacerbate markers of inflammation in cocultures of human enterocytes and leukocytes

    DEFF Research Database (Denmark)

    Parlesak, Alexandr; Negrier, I.; Neveux, N.

    2007-01-01

    the catabolism of serine, asparagine, and lysine, and reduced glutamine catabolism. Addition of arginine increased ornithine formation and moderately reduced transepithelial transport of methionine and other amino acids. Hence, arginine supplementation does not interfere with inflammation-associated cross......Enteral arginine supplementation in the critically ill has become a matter of controversy. In this study, we investigated effects of the addition of 0.4 and 1.2 mmol/L arginine in a coculture model on markers of inflammation, enterocyte layer integrity, and amino acid transport. In this model...... with arginine did not affect epithelial integrity, production of any of the cytokines investigated, or the amount of nitric oxide. The amino acid used primarily by nonstimulated intestinal epithelial cells cocultured with leukocytes was glutamine. Activation of IEC with bacteria significantly enhanced...

  5. Intestinal surfactant permeation enhancers and their interaction with enterocyte cell membranes in a mucosal explant system

    DEFF Research Database (Denmark)

    Danielsen, E Michael; Hansen, Gert H

    2017-01-01

    Intestinal permeation enhancers (PEs) are agents aimed to improve oral delivery of therapeutic drugs with poor bioavailability. The main permeability barrier for oral delivery is the intestinal epithelium, and PEs act to increase the paracellular and/or transcellular passage of drugs. Transcellular....... In the present work, the interaction of the surfactants lauroyl-L-carnitine, 1-decanoyl-rac-glycerol, and nonaethylene glycol monododecyl ether with the intestinal epithelium was studied in organ cultured pig jejunal mucosal explants. As expected, at 2 mM, these agents rapidly permeabilized the enterocytes...... for the fluorescent polar tracer lucifer yellow, but surprisingly, they all also blocked both constitutive -and receptor-mediated pathways of endocytosis from the brush border, indicating a complete arrest of apical membrane trafficking. At the ultrastructural level, the PEs caused longitudinal fusion of brush border...

  6. Intestinal absorption of vitamin D: from the meal to the enterocyte.

    Science.gov (United States)

    Reboul, Emmanuelle

    2015-02-01

    Vitamin D plays key roles in bone, infectious, inflammatory and metabolic diseases. As most people get inadequate sun exposure for sufficient vitamin D status, they need adequate intake of dietary vitamin D. Many studies see optimizing vitamin D status as a public health priority. It is thus vital to gain deeper insight into vitamin D intestinal absorption. It was long assumed that vitamin D intestinal absorption is a passive process, but new data from our laboratory showed that it is actually far more complex than previously thought. This review describes the fate of vitamin D in the human upper gastrointestinal lumen during digestion and focuses on the proteins involved in the intestinal membrane and cellular transport of vitamin D across the enterocyte. Although recent data significantly improve our understanding of vitamin D intestinal absorption, further studies are still needed to increase our knowledge of the molecular mechanisms underlying this phenomenon.

  7. Investigation of the Assembly of Chylomicrons in Hamster Enterocytes Using Pluronic-L81 Acid as a Probe

    Directory of Open Access Journals (Sweden)

    Mahnaz Mardani

    2011-06-01

    Full Text Available A major function of the enterocytes is absorption, processing, and export of dietary lipids into the lymphatic system. Pluronic L-81 is a non-ionic hydrophobic surfactant, which specifically inhibits lipid absorption in the intestine when administered in vivo. This compound is therefore an attractive probe to perturb and investigate the molecular and intracellular events in chylomicron assembly in the enterocytes. In the present study pluronic acid was administered to hamsters followed by isolation of the enterocytes and cell fractionation to investigate the effect of pluronic acid on intracellular events in lipid absorption. Four types of diet were administered to hamsters for three weeks; low-fat chow, high-fat chow and each diet with or without added pluronic acid. Sub-cellular fractions of freshly isolated enterocytes were prepared. Consistent with morphological observation, the high fat diet resulted in a three-fold increase in the triacylglycerol (TAG content of the enterocytes and addition of pluronic acid to either the low fat or the high fat diets resulted in a ten-fold increase in cellular TAG levels. Determination of the mass of TAG and the time course of incorporation of 3H-triolein, administered by gavage, showed that the increased TAG was recovered in the microsomal (endoplasmic reticulum fraction and the cytosol. In microsomes, increased TAG was recovered mainly in the membrane although there was a significant amount in the microsomal luminal contents. Pluronic acid therefore acts at the level of the endoplasmic reticulum and inhibits the assembly of apo-B48 with chylomicron TAG. The excess TAG is transferred to cytosolic stores.

  8. Enterohemorrhagic Escherichia coli induce attaching and effacing lesions and hemorrhagic colitis in human and bovine intestinal xenograft models

    Directory of Open Access Journals (Sweden)

    Lilach Golan

    2011-01-01

    Enterohemorrhagic Escherichia coli (EHEC O157:H7 is an important cause of diarrhea, hemorrhagic colitis and hemolytic uremic syndrome in humans worldwide. The two major virulence determinants of EHEC are the Shiga toxins (Stx and the type III secretion system (T3SS, including the injected effectors. Lack of a good model system hinders the study of EHEC virulence. Here, we investigated whether bovine and human intestinal xenografts in SCID mice can be useful for studying EHEC and host tissue interactions. Fully developed, germ-free human and bovine small intestine and colon were established by subcutaneous transplantation of human and bovine fetal gut into SCID mice. Xenografts were allowed to develop for 3–4 months and thereafter were infected by direct intraluminal inoculation of Stx-negative derivatives of EHEC O157:H7, strain EDL933. The small intestine and colon xenografts closely mimicked the respective native tissues. Upon infection, EHEC induced formation of typical attaching and effacing lesions and tissue damage that resembled hemorrhagic colitis in colon xenografts. By contrast, xenografts infected with an EHEC mutant deficient in T3SS remained undamaged. Furthermore, EHEC did not attach to or damage the epithelium of small intestinal tissue, and these xenografts remained intact. EHEC damaged the colon in a T3SS-dependent manner, and this model is therefore useful for studying the molecular details of EHEC interactions with live human and bovine intestinal tissue. Furthermore, we demonstrate that Stx and gut microflora are not essential for EHEC virulence in the human gut.

  9. Anti-glycosyl antibodies in lipid rafts of the enterocyte brush border: a possible host defense against pathogens

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Pedersen, Esben D K; Immerdal, Lissi

    2005-01-01

    a major part of the immunoglobulins at the lumenal surface of the gut. The antibodies were associated with lipid rafts at the brush border, and they frequently (52%) coclustered with the raft marker galectin 4. A lactose wash increased the susceptibility of the brush border toward lectin peanut agglutin...

  10. Impairment of Swimming Motility by Antidiarrheic Lactobacillus acidophilus Strain LB Retards Internalization of Salmonella enterica Serovar Typhimurium within Human Enterocyte-Like Cells▿

    Science.gov (United States)

    Liévin-Le Moal, Vanessa; Amsellem, Raymonde; Servin, Alain L.

    2011-01-01

    We report that both culture and the cell-free culture supernatant (CFCS) of Lactobacillus acidophilus strain LB (Lactéol Boucard) have the ability (i) to delay the appearance of Salmonella enterica serovar Typhimurium strain SL1344-induced mobilization of F-actin and, subsequently, (ii) to retard cell entry by S. Typhimurium SL1344. Time-lapse imaging and Western immunoblotting showed that S. Typhimurium SL1344 swimming motility, as represented by cell tracks of various types, was rapidly but temporarily blocked without affecting the expression of FliC flagellar propeller protein. We show that the product(s) secreted by L. acidophilus LB that supports the inhibitory activity is heat stable and of low molecular weight. The product(s) caused rapid depolarization of the S. Typhimurium SL1344 cytoplasmic membrane without affecting bacterial viability. We identified inhibition of swimming motility as a newly discovered mechanism by which the secreted product(s) of L. acidophilus strain LB retards the internalization of the diarrhea-associated pathogen S. enterica serovar Typhimurium within cultured human enterocyte-like cells. PMID:21825295

  11. Impairment of swimming motility by antidiarrheic Lactobacillus acidophilus strain LB retards internalization of Salmonella enterica serovar Typhimurium within human enterocyte-like cells.

    Science.gov (United States)

    Liévin-Le Moal, Vanessa; Amsellem, Raymonde; Servin, Alain L

    2011-10-01

    We report that both culture and the cell-free culture supernatant (CFCS) of Lactobacillus acidophilus strain LB (Lactéol Boucard) have the ability (i) to delay the appearance of Salmonella enterica serovar Typhimurium strain SL1344-induced mobilization of F-actin and, subsequently, (ii) to retard cell entry by S. Typhimurium SL1344. Time-lapse imaging and Western immunoblotting showed that S. Typhimurium SL1344 swimming motility, as represented by cell tracks of various types, was rapidly but temporarily blocked without affecting the expression of FliC flagellar propeller protein. We show that the product(s) secreted by L. acidophilus LB that supports the inhibitory activity is heat stable and of low molecular weight. The product(s) caused rapid depolarization of the S. Typhimurium SL1344 cytoplasmic membrane without affecting bacterial viability. We identified inhibition of swimming motility as a newly discovered mechanism by which the secreted product(s) of L. acidophilus strain LB retards the internalization of the diarrhea-associated pathogen S. enterica serovar Typhimurium within cultured human enterocyte-like cells.

  12. Targeted Amplicon Sequencing for Single-Nucleotide-Polymorphism Genotyping of Attaching and Effacing Escherichia coli O26:H11 Cattle Strains via a High-Throughput Library Preparation Technique.

    Science.gov (United States)

    Ison, Sarah A; Delannoy, Sabine; Bugarel, Marie; Nagaraja, Tiruvoor G; Renter, David G; den Bakker, Henk C; Nightingale, Kendra K; Fach, Patrick; Loneragan, Guy H

    2016-01-15

    Enterohemorrhagic Escherichia coli (EHEC) O26:H11, a serotype within Shiga toxin-producing E. coli (STEC) that causes severe human disease, has been considered to have evolved from attaching and effacing E. coli (AEEC) O26:H11 through the acquisition of a Shiga toxin-encoding gene. Targeted amplicon sequencing using next-generation sequencing technology of 48 phylogenetically informative single-nucleotide polymorphisms (SNPs) and three SNPs differentiating Shiga toxin-positive (stx-positive) strains from Shiga toxin-negative (stx-negative) strains were used to infer the phylogenetic relationships of 178 E. coli O26:H11 strains (6 stx-positive strains and 172 stx-negative AEEC strains) from cattle feces to 7 publically available genomes of human clinical strains. The AEEC cattle strains displayed synonymous SNP genotypes with stx2-positive sequence type 29 (ST29) human O26:H11 strains, while stx1 ST21 human and cattle strains clustered separately, demonstrating the close phylogenetic relatedness of these Shiga toxin-negative AEEC cattle strains and human clinical strains. With the exception of seven stx-negative strains, five of which contained espK, three stx-related SNPs differentiated the STEC strains from non-STEC strains, supporting the hypothesis that these AEEC cattle strains could serve as a potential reservoir for new or existing pathogenic human strains. Our results support the idea that targeted amplicon sequencing for SNP genotyping expedites strain identification and genetic characterization of E. coli O26:H11, which is important for food safety and public health. Copyright © 2016 Ison et al.

  13. Inhibition of IKKß in enterocytes exacerbates sepsis-induced intestinal injury and worsens mortality

    Science.gov (United States)

    Dominguez, Jessica A.; Samocha, Alexandr J.; Liang, Zhe; Burd, Eileen M.; Farris, Alton B.; Coopersmith, Craig M.

    2013-01-01

    Objective NF-kB is a critical regulator of cell survival genes and the host inflammatory response. The purpose of this study was to investigate the role of enterocyte-specific NF-kB in sepsis through selective ablation of IkB kinase (IKK)-ß. Design Prospective, randomized, controlled study. Setting Animal laboratories in university medical centers. Subjects and Interventions Mice lacking functional NF-kB in their intestinal epithelium (Vil-Cre/Ikkßf/Δ) and wild type (WT) mice were subjected to sham laparotomy or cecal ligation and puncture (CLP). Animals were sacrified at 24 hours or followed seven days for survival. Measurements and Main Results Septic WT mice had decreased villus length compared to sham mice while villus atrophy was further exacerbated in septic Vil-Cre/Ikkßf/Δ mice. Sepsis induced an increase in intestinal epithelial apoptosis compared to sham mice which was further exacerbated in Vil-Cre/Ikkßf/Δ mice. Sepsis induced intestinal hyperpermeability in WT mice compared to sham mice, which was further exacerbated in septic Vil-Cre/Ikkßf/Δ mice. This was associated with increased intestinal expression of claudin-2 in septic WT mice, which was further increased in septic Vil-Cre/Ikkßf/Δ mice. Both, pro-inflammatory and anti-inflammatory cytokines were increased in serum following CLP, and IL-10 and MCP-1 levels were higher in septic Vil-Cre/Ikkßf/Δ mice than septic WT mice. All septic mice were bacteremic, but no differences in bacterial load were identified between WT and Vil-Cre/Ikkßf/Δ mice. To determine the functional significance of these results, animals were followed for survival. Septic WT mice had lower mortality than septic Vil-Cre/Ikkßf/Δ mice (47% vs. 80%, p<0.05). Anti-TNF administration decreased intestinal apoptosis, permeability and mortality in WT septic mice and a similar improvement in intestinal integrity and survival were seen when anti-TNF was given to Vil-Cre/Ikkßf/Δ mice. Conclusions Enterocyte-specific NF

  14. Inhibition of IKKβ in enterocytes exacerbates sepsis-induced intestinal injury and worsens mortality.

    Science.gov (United States)

    Dominguez, Jessica A; Samocha, Alexandr J; Liang, Zhe; Burd, Eileen M; Farris, Alton B; Coopersmith, Craig M

    2013-10-01

    Nuclear factor-κB is a critical regulator of cell-survival genes and the host inflammatory response. The purpose of this study was to investigate the role of enterocyte-specific NF-kB in sepsis through selective ablation of IkB kinase. Prospective, randomized controlled study. Animal laboratories in university medical centers. Mice lacking functional NF-kB in their intestinal epithelium (Vil-Cre/Ikkβ) and wild-type mice were subjected to sham laparotomy or cecal ligation and puncture. Animals were killed at 24 hours or followed 7 days for survival. Septic wild-type mice had decreased villus length compared with sham mice, whereas villus atrophy was further exacerbated in septic Vil-Cre/Ikkβ mice. Sepsis induced an increase in intestinal epithelial apoptosis compared with sham mice, which was further exacerbated in Vil-Cre/Ikkβ mice. Sepsis induced intestinal hyperpermeability in wild-type mice compared with sham mice, which was further exacerbated in septic Vil-Cre/Ikkβ mice. This was associated with increased intestinal expression of claudin-2 in septic wild-type mice, which was further increased in septic Vil-Cre/Ikkβ mice. Both, pro-inflammatory and anti-inflammatory cytokines were increased in serum following cecal ligation and puncture, and interleukin 10 and monocyte chemoattractant protein-1 levels were higher in septic Vil-Cre/Ikkβ mice than in septic wild-type mice. All septic mice were bacteremic, but no differences in bacterial load were identified between wild-type and Vil-Cre/Ikkβ mice. To determine the functional significance of these results, animals were followed for survival. Septic wild-type mice had lower mortality than septic Vil-Cre/Ikkβ mice (47% vs 80%, p<0.05). Antitumor necrosis factor administration decreased intestinal apoptosis, permeability, and mortality in wild-type septic mice, and a similar improvement in intestinal integrity and survival were seen when antitumor necrosis factor was given to Vil-Cre/Ikkβ mice. Enterocyte

  15. Immunomicroscopic localization of the 10,000 molecular weight calcium-binding protein in the human enterocyte

    DEFF Research Database (Denmark)

    Staun, M; Friis, S; Dabelsteen, E

    1989-01-01

    The cellular localization of the 10,000 molecular weight calcium-binding protein (CaBP or Calbindin-D) in the small intestinal epithelium of man was investigated by immunofluorescence and immunoelectron microscopy (immunogold staining). Indirect immunofluorescence on frozen sections showed...... intracellular staining in the enterocyte. The fluorescence was evenly distributed and no significant differences were observed between crypt and villus cells. No staining was found in goblet cells or in the submucosa. Correspondingly, immunogold labeled antibodies were scattered over the cytoplasm...... of the enterocyte. The terminal region appeared to be the most intensely decorated and the brush border region showed labeling above the background level. No labeling was associated with intracellular membranes or the basolateral membrane....

  16. Fish oil feeding is associated with an increased accumulation of dietary lipids in enterocytes: Results from an in vivo study in rats

    DEFF Research Database (Denmark)

    Larsen, L.F.; Marckmann, P.; Hansen, A.K.

    2003-01-01

    contents of enterocytes were determined by liquid scintillation counting. Two other groups of rats (2 x 6) fed the experimental diets were given an oral fat load and fasting and postprandial blood samples were taken. Results: The accumulation of H-3-lipids in enterocytes was higher in rats fed fish oil...... than in controls (area under the H-3-lipid time curve: 1041.3 versus 670.3 nmol oleic acid x min/mug DNA, P

  17. Effect of monoassociation with probiotic strain Bifidobacterium bifidum on enterocyte brush-border enzymes in gnotobiotic mice

    Czech Academy of Sciences Publication Activity Database

    Kozáková, Hana; Řeháková, Zuzana; Kolínská, Jiřina; Tlaskalová, Helena

    2002-01-01

    Roč. 88, č. 1 (2002), s. 113 ISSN 0007-1145. [Probiotics and Health /2001./. London, 13.09.2002-14.09.2002] R&D Projects: GA ČR GA306/99/1383; GA ČR GA310/01/0933; GA AV ČR IAA5020101 Keywords : enterocyte * brush * border Subject RIV: EE - Microbiology, Virology Impact factor: 2.491, year: 2002

  18. The role of enterocyte defects in the pathogenesis of congenital diarrheal disorders

    Directory of Open Access Journals (Sweden)

    Arend W. Overeem

    2016-01-01

    Full Text Available Congenital diarrheal disorders are rare, often fatal, diseases that are difficult to diagnose (often requiring biopsies and that manifest in the first few weeks of life as chronic diarrhea and the malabsorption of nutrients. The etiology of congenital diarrheal disorders is diverse, but several are associated with defects in the predominant intestinal epithelial cell type, enterocytes. These particular congenital diarrheal disorders (CDDENT include microvillus inclusion disease and congenital tufting enteropathy, and can feature in other diseases, such as hemophagocytic lymphohistiocytosis type 5 and trichohepatoenteric syndrome. Treatment options for most of these disorders are limited and an improved understanding of their molecular bases could help to drive the development of better therapies. Recently, mutations in genes that are involved in normal intestinal epithelial physiology have been associated with different CDDENT. Here, we review recent progress in understanding the cellular mechanisms of CDDENT. We highlight the potential of animal models and patient-specific stem-cell-based organoid cultures, as well as patient registries, to integrate basic and clinical research, with the aim of clarifying the pathogenesis of CDDENT and expediting the discovery of novel therapeutic strategies.

  19. [Analysis of the biorhythm frequency of bordered enterocytes during normal and inverted feeding regimens].

    Science.gov (United States)

    Liashko, O G

    1977-10-01

    The study was performed during the period close to equinox in 236 male mice C57 Bl strain, sacrificed at equal intervals during 5 days. In paraffin sections, 5--6 mcm thick, stained after Dominici-Kedrovsky, with additional application of PAS-reaction and alcian blue, the cell height and width in the small intestine border enterocyte zone were determined. Calculation of autocorrelative function with the following determination of spectral density, infradian, circadian and ultradian biorhythmical components were estimated, as well as their changes under the influence of feeding regime inversion. At evening feeding, the greatest width of the brush border coinsides the beginning and the end of the digestion period. The width of the dark apical zone, where mitochondria are concentrated, synchronously changes at the end of digestion with the brush border, and then- with the cell basal zone. At morning feeding, by the degree of circadian phase change, the most liable are the indices reflecting organoid status, which are closely involved in absorbtion processes. Ultradian rhythm produces, on the background of circadian changes, additional raisis and abatements. Spectral composition, under inadequate feeding, is demonstrated to become more complex, mainly at the expense of ultradian rhythms, that speaks of their importance for the processes of adaptive rhythmical rearrangement.

  20. Deficiency in DNA damage response of enterocytes accelerates intestinal stem cell aging inDrosophila.

    Science.gov (United States)

    Park, Joung-Sun; Jeon, Ho-Jun; Pyo, Jung-Hoon; Kim, Young-Shin; Yoo, Mi-Ae

    2018-03-07

    Stem cell dysfunction is closely linked to tissue and organismal aging and age-related diseases, and heavily influenced by the niche cells' environment. The DNA damage response (DDR) is a key pathway for tissue degeneration and organismal aging; however, the precise protective role of DDR in stem cell/niche aging is unclear. The Drosophila midgut is an excellent model to study the biology of stem cell/niche aging because of its easy genetic manipulation and its short lifespan. Here, we showed that deficiency of DDR in Drosophila enterocytes (ECs) accelerates intestinal stem cell (ISC) aging. We generated flies with knockdown of Mre11 , Rad50 , Nbs1 , ATM , ATR , Chk1 , and Chk2 , which decrease the DDR system in ECs. EC-specific DDR depletion induced EC death, accelerated the aging of ISCs, as evidenced by ISC hyperproliferation, DNA damage accumulation, and increased centrosome amplification, and affected the adult fly's survival. Our data indicated a distinct effect of DDR depletion in stem or niche cells on tissue-resident stem cell proliferation. Our findings provide evidence of the essential role of DDR in protecting EC against ISC aging, thus providing a better understanding of the molecular mechanisms of stem cell/niche aging.

  1. Transactivation of EGFR by LPS induces COX-2 expression in enterocytes.

    Directory of Open Access Journals (Sweden)

    Steven J McElroy

    Full Text Available Necrotizing enterocolitis (NEC is the leading cause of gastrointestinal morbidity and mortality in preterm infants. NEC is characterized by an exaggerated inflammatory response to bacterial flora leading to bowel necrosis. Bacterial lipopolysaccharide (LPS mediates inflammation through TLR4 activation and is a key molecule in the pathogenesis of NEC. However, LPS also induces cyclooxygenase-2 (COX-2, which promotes intestinal barrier restitution through stimulation of intestinal cell survival, proliferation, and migration. Epidermal growth factor receptor (EGFR activation prevents experimental NEC and may play a critical role in LPS-stimulated COX-2 production. We hypothesized that EGFR is required for LPS induction of COX-2 expression. Our data show that inhibiting EGFR kinase activity blocks LPS-induced COX-2 expression in small intestinal epithelial cells. LPS induction of COX-2 requires Src-family kinase signaling while LPS transactivation of EGFR requires matrix metalloprotease (MMP activity. EGFR tyrosine kinase inhibitors block LPS stimulation of mitogen-activated protein kinase ERK, suggesting an important role of the MAPK/ERK pathway in EGFR-mediated COX-2 expression. LPS stimulates proliferation of IEC-6 cells, but this stimulation is inhibited with either the EGFR kinase inhibitor AG1478, or the selective COX-2 inhibitor Celecoxib. Taken together, these data show that EGFR plays an important role in LPS-induction of COX-2 expression in enterocytes, which may be one mechanism for EGF in inhibition of NEC.

  2. Incorporation of n-3 polyunsaturated fatty acids of marine or vegetable origin into rat enterocyte phospholipids

    DEFF Research Database (Denmark)

    Poulsen, Christian; Christensen, Michael Søberg; Høy, Carl-Erik

    1997-01-01

    We examined time related effects of an intake of n-3 polyunsaturated fatty acids (PUFA) on the fatty acid profiles of rat enterocyte phospholipids. Three diets containing 20 wt% fat with similar levels of linoleic acid (C18:2n-6), approximately 11 wt% of the fatty acids, were prepared. The diets...... were: Palm oil diet (PD), 0.6 wt% n-3 PUFA; fish oil diet (FD), 32 wt% n-3 PUFA (C20-C22); and linseed oil diet (LD), 32 wt% n-3 PUFA (C18:3n-3). Forty weanling male Wistar rats were fed PD for 34 days and then divided into three groups. Two groups of sixteen rats each were then fed FD or LD....... Desaturation and elongation products of C18:3n-3, such as C20:5n-3, C22:5n-3 and C22:6n-3, were observed following intake of LD. All three groups contained approximately 40 mol% of saturated fatty acids in the intestinal phospholipids. Copyright (C) 1996 Elsevier Science Inc....

  3. Trans-resveratrol induces a potential anti-lipogenic effect in lipopolysaccharide-stimulated enterocytes.

    Science.gov (United States)

    Etxeberria, U; Castilla-Madrigal, R; Lostao, M P; Martínez, J A; Milagro, F I

    2015-12-09

    A DNA microarray analysis was conducted in Caco-2 cells to analyse the protective effects of trans-resveratrol on enterocyte physiology and metabolism in pro-inflammatory conditions. Cells were pre-treated with 50 μΜ of trans-resveratrol and, subsequently, lipopolysaccharide (LPS) was added for 48 h. The microarray analysis revealed 121 genes differentially expressed between resveratrol-treated and non-treated cells (B> 0, is the odd thatthe gene is differentially expressed). Inhibitor of DNA binding 1 (ID1), histidine-rich glycoprotein (HRG), NADPH oxidase (NOX1) and sprouty homolog 1 (SPRY), were upregulated by LPS treatment, but significantly blocked by trans-resveratrol pre-treatment (padj< 0.05, after adjusting for Benjamini-Hocheberg procedure). Moreover, genes implicated in synthesis of lipids (z-score= -1.195) and concentration of cholesterol (z-score= -0.109), were markedly downregulated by trans-resveratrol. Other genes involved in fat turnover, but also in cell death and survival function, such as transcription factors Krüppel-like factor 5 (KLF5) and amphiregulin (AREG), were also significantly inhibited by trans-resveratrol pre-treatment. RT-qPCR-data confirmed the microarray results. Special mention deserves acyl-CoA synthetase long-chain family member 3 (ACSL3) and endothelial lipase (LIPG), which were downregulated by this stilbene and have been previously associated with fatty acid synthesis and obesity in other tissues. This study envisages that trans-resveratrol might exert an important anti-lipogenic effect at intestinal level under pro-inflammatory conditions, which has not been previously described.

  4. Proteomic Analysis of Lipid Droplets from Caco-2/TC7 Enterocytes Identifies Novel Modulators of Lipid Secretion

    Science.gov (United States)

    Beilstein, Frauke; Bouchoux, Julien; Rousset, Monique; Demignot, Sylvie

    2013-01-01

    In enterocytes, the dynamic accumulation and depletion of triacylglycerol (TAG) in lipid droplets (LD) during fat absorption suggests that cytosolic LD-associated TAG contribute to TAG-rich lipoprotein (TRL) production. To get insight into the mechanisms controlling the storage/secretion balance of TAG, we used as a tool hepatitis C virus core protein, which localizes onto LDs, and thus may modify their protein coat and decrease TRL secretion. We compared the proteome of LD fractions isolated from Caco-2/TC7 enterocytes expressing or not hepatitis C virus core protein by a differential proteomic approach (isobaric tag for relative and absolute quantitation (iTRAQ) labeling coupled with liquid chromatography and tandem mass spectrometry). We identified 42 proteins, 21 being involved in lipid metabolism. Perilipin-2/ADRP, which is suggested to stabilize long term-stored TAG, was enriched in LD fractions isolated from Caco-2/TC7 expressing core protein while perilipin-3/TIP47, which is involved in LD synthesis from newly synthesized TAG, was decreased. Endoplasmic reticulum-associated proteins were strongly decreased, suggesting reduced interactions between LD and endoplasmic reticulum, where TRL assembly occurs. For the first time, we show that 17β-hydroxysteroid dehydrogenase 2 (DHB2), which catalyzes the conversion of 17-keto to 17 β-hydroxysteroids and which was the most highly enriched protein in core expressing cells, is localized to LD and interferes with TAG secretion, probably through its capacity to inactivate testosterone. Overall, we identified potential new players of lipid droplet dynamics, which may be involved in the balance between lipid storage and secretion, and may be altered in enterocytes in pathological conditions such as insulin resistance, type II diabetes and obesity. PMID:23301014

  5. Proteomic analysis of lipid droplets from Caco-2/TC7 enterocytes identifies novel modulators of lipid secretion.

    Directory of Open Access Journals (Sweden)

    Frauke Beilstein

    Full Text Available In enterocytes, the dynamic accumulation and depletion of triacylglycerol (TAG in lipid droplets (LD during fat absorption suggests that cytosolic LD-associated TAG contribute to TAG-rich lipoprotein (TRL production. To get insight into the mechanisms controlling the storage/secretion balance of TAG, we used as a tool hepatitis C virus core protein, which localizes onto LDs, and thus may modify their protein coat and decrease TRL secretion. We compared the proteome of LD fractions isolated from Caco-2/TC7 enterocytes expressing or not hepatitis C virus core protein by a differential proteomic approach (isobaric tag for relative and absolute quantitation (iTRAQ labeling coupled with liquid chromatography and tandem mass spectrometry. We identified 42 proteins, 21 being involved in lipid metabolism. Perilipin-2/ADRP, which is suggested to stabilize long term-stored TAG, was enriched in LD fractions isolated from Caco-2/TC7 expressing core protein while perilipin-3/TIP47, which is involved in LD synthesis from newly synthesized TAG, was decreased. Endoplasmic reticulum-associated proteins were strongly decreased, suggesting reduced interactions between LD and endoplasmic reticulum, where TRL assembly occurs. For the first time, we show that 17β-hydroxysteroid dehydrogenase 2 (DHB2, which catalyzes the conversion of 17-keto to 17 β-hydroxysteroids and which was the most highly enriched protein in core expressing cells, is localized to LD and interferes with TAG secretion, probably through its capacity to inactivate testosterone. Overall, we identified potential new players of lipid droplet dynamics, which may be involved in the balance between lipid storage and secretion, and may be altered in enterocytes in pathological conditions such as insulin resistance, type II diabetes and obesity.

  6. Co- and Post-Treatment with Lysine Protects Primary Fish Enterocytes against Cu-Induced Oxidative Damage.

    Directory of Open Access Journals (Sweden)

    Xue-Yin Li

    Full Text Available The aim of the work was primarily to explore the protective activity pathways of lysine against oxidative damage in fish in vivo and in enterocytes in vitro. First, grass carp were fed diets containing six graded levels of lysine (7.1-19.6 g kg-1 diet for 56 days. Second, the enterocytes were treated with different concentrations of lysine (0-300 mg/L in media prior to (pre-treatment, along with (co-treatment or following (post-treatment with 6 mg/L of Cu for 24 h. The results indicated that lysine improved grass carp growth performance. Meanwhile, lysine ameliorated lipid and protein oxidation by elevating the gene expression and activity of antioxidant enzymes (superoxide dismutase (SOD, glutathioneperoxidase (GPx, glutathione-S-transferase (GST and reductase (GR, and nuclear factor erythroid 2-related factor 2 (Nrf2 mRNA levels in fish intestine. The in vitro studies showed that co- and post-treatment with lysine conferred significant protection against Cu-induced oxidative damage in fish primary enterocytes as measured by 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT OD values, along with alkaline phosphatase (ALP and lactate dehydrogenase activities, and the depletion of protein carbonyl (PC, malondialdehyde (MDA and 8-hydroxydeoxyguanosine contents. Moreover, lysine co-treatment decreased the activities and mRNA level of cellular SOD, GPx, GST and GR compared with the Cu-only exposed group. Gene expression of the signalling molecule Nrf2 showed the same pattern as that of SOD activity, whereas Kelch-like ECH-associated protein 1b (Keap1b followed the opposite trend, indicating that co-treatment with lysine induced antioxidant enzymes that protected against oxidative stress through Nrf2 pathway. In addition, post-treatment with lysine increased proteasomal activity and blocked the Cu-stimulated increase in mRNA levels of GST and associated catalase (CAT and GST activities (P<0.01 and P<0.001. GR activity and gene

  7. Rapid reversal of human intestinal ischemia-reperfusion induced damage by shedding of injured enterocytes and reepithelialisation.

    Directory of Open Access Journals (Sweden)

    Joep P M Derikx

    Full Text Available BACKGROUND: Intestinal ischemia-reperfusion (IR is a phenomenon related to physiological conditions (e.g. exercise, stress and to pathophysiological events (e.g. acute mesenteric ischemia, aortic surgery. Although intestinal IR has been studied extensively in animals, results remain inconclusive and data on human intestinal IR are scarce. Therefore, an experimental harmless model for human intestinal IR was developed, enabling us to clarify the sequelae of human intestinal IR for the first time. METHODS AND FINDINGS: In 30 patients undergoing pancreatico-duodenectomy we took advantage of the fact that in this procedure a variable length of jejunum is removed. Isolated jejunum (5 cm was subjected to 30 minutes ischemia followed by reperfusion. Intestinal Fatty Acid Binding Protein (I-FABP arteriovenous concentration differences across the bowel segment were measured before and after ischemia to assess epithelial cell damage. Tissue sections were collected after ischemia and at 25, 60 and 120 minutes reperfusion and stained with H&E, and for I-FABP and the apoptosis marker M30. Bonferroni's test was used to compare I-FABP differences. Mean (SEM arteriovenous concentration gradients of I-FABP across the jejunum revealed rapidly developing epithelial cell damage. I-FABP release significantly increased from 290 (46 pg/ml before ischemia towards 3,997 (554 pg/ml immediately after ischemia (p<0.001 and declined gradually to 1,143 (237 pg/ml within 1 hour reperfusion (p<0.001. Directly after ischemia the intestinal epithelial lining was microscopically normal, while subepithelial spaces appeared at the villus tip. However, after 25 minutes reperfusion, enterocyte M30 immunostaining was observed at the villus tip accompanied by shedding of mature enterocytes into the lumen and loss of I-FABP staining. Interestingly, within 60 minutes reperfusion the epithelial barrier resealed, while debris of apoptotic, shedded epithelial cells was observed in the lumen

  8. Activation of peroxisome proliferator-activated receptor-α (PPARα) suppresses postprandial lipidemia through fatty acid oxidation in enterocytes

    International Nuclear Information System (INIS)

    Kimura, Rino; Takahashi, Nobuyuki; Murota, Kaeko; Yamada, Yuko; Niiya, Saori; Kanzaki, Noriyuki; Murakami, Yoko; Moriyama, Tatsuya; Goto, Tsuyoshi; Kawada, Teruo

    2011-01-01

    Highlights: → PPARα activation increased mRNA expression levels of fatty acid oxidation-related genes in human intestinal epithelial Caco-2 cells. → PPARα activation also increased oxygen consumption rate and CO 2 production and decreased secretion of triglyceride and ApoB from Caco-2 cells. → Orally administration of bezafibrate increased mRNA expression levels of fatty acid oxidation-related genes and CO 2 production in small intestinal epithelial cells. → Treatment with bezafibrate decreased postprandial serum concentration of triglyceride after oral injection of olive oil in mice. → It suggested that intestinal lipid metabolism regulated by PPARα activation suppresses postprandial lipidemia. -- Abstract: Activation of peroxisome proliferator-activated receptor (PPAR)-α which regulates lipid metabolism in peripheral tissues such as the liver and skeletal muscle, decreases circulating lipid levels, thus improving hyperlipidemia under fasting conditions. Recently, postprandial serum lipid levels have been found to correlate more closely to cardiovascular diseases than fasting levels, although fasting hyperlipidemia is considered an important risk of cardiovascular diseases. However, the effect of PPARα activation on postprandial lipidemia has not been clarified. In this study, we examined the effects of PPARα activation in enterocytes on lipid secretion and postprandial lipidemia. In Caco-2 enterocytes, bezafibrate, a potent PPARα agonist, increased mRNA expression levels of fatty acid oxidation-related genes, such as acyl-CoA oxidase, carnitine palmitoyl transferase, and acyl-CoA synthase, and oxygen consumption rate (OCR) and suppressed secretion levels of both triglycerides and apolipoprotein B into the basolateral side. In vivo experiments revealed that feeding high-fat-diet containing bezafibrate increased mRNA expression levels of fatty acid oxidation-related genes and production of CO 2 and acid soluble metabolites in enterocytes. Moreover

  9. Infrared Spectroscopy as a Tool to Study the Antioxidant Activity of Polyphenolic Compounds in Isolated Rat Enterocytes

    Science.gov (United States)

    Barraza-Garza, Guillermo; Castillo-Michel, Hiram; de la Rosa, Laura A.; Martinez-Martinez, Alejandro; Pérez-León, Jorge A.; Cotte, Marine; Alvarez-Parrilla, Emilio

    2016-01-01

    The protective effect of different polyphenols, catechin (Cat), quercetin (Qc) (flavonoids), gallic acid (GA), caffeic acid (CfA), chlorogenic acid (ChA) (phenolic acids), and capsaicin (Cap), against H2O2-induced oxidative stress was evaluated in rat enterocytes using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) Spectroscopy and Fourier Transform Infrared Microspectroscopy (FTIRM), and results were compared to standard lipid peroxidation techniques: conjugated dienes (CD) and Thiobarbituric Acid Reactive Substances (TBARS). Analysis of ATR-FTIR and FTIRM spectral data allowed the simultaneous evaluation of the effects of H2O2 and polyphenols on lipid and protein oxidation. All polyphenols showed a protective effect against H2O2-induced oxidative stress in enterocytes, when administered before or after H2O2. Cat and capsaicin showed the highest protective effect, while phenolic acids had weaker effects and Qc presented a mild prooxidative effect (IR spectral profile of biomolecules between control and H2O2-treated cells) according to FTIR analyses. These results demonstrated the viability to use infrared spectroscopy to evaluate the oxidant and antioxidant effect of molecules in cell systems assays. PMID:27213031

  10. Fungal Deoxynivalenol-Induced Enterocyte Distress Is Attenuated by Adulterated Adlay: In Vitro Evidences for Mucoactive Counteraction

    Directory of Open Access Journals (Sweden)

    Zhimin Du

    2018-02-01

    Full Text Available Adlay is a cereal crop that has long been used as traditional herbal medicine and as a highly nourishing food. However, deoxynivalenol (DON, the most prevalent trichothecene mycotoxin worldwide, frequently spoils grains, including adlay, via fungal infection. On the basis of an assumption that the actions of DON in the gut could be modified by adlay consumption, we simulated the impacts of co-exposure in enterocytes and investigated the effectiveness of treatment with adlay for reducing the risk of DON-induced inflammation and epithelia barrier injury. In particular, adlay suppressed DON-induced pro-inflammatory signals such as mitogen-activated kinase transduction and the epidermal growth factor receptor-linked pathway. In addition to regulation of pro-inflammatory responses, adlay treatment interfered with DON-induced disruption of the epithelial barrier. Mechanistically, adlay could boost the activation of protein kinase C (PKC and cytosolic translocation of human antigen R (HuR protein, which played critical roles in the epithelial restitution, resulting in protection against disruption of enterocyte barrier integrity. Notably, DON abrogated the Ras homolog gene family member A GTPase-mediated actin cytoskeletal network, which was diminished by adlay treatment in PKC and HuR-dependent ways. Taken together, this study provides evidences for adlay-based attenuation of trichothecene-induced gut distress, implicating potential use of a new gut protector against enteropathogenic insults in diets.

  11. Scavenger receptor class B type I (SR-BI) in pig enterocytes: trafficking from the brush border to lipid droplets during fat absorption

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Niels-Christiansen, Lise-Lotte W; Immerdal, Lissi

    2003-01-01

    BACKGROUND: Scavenger receptor class B type I (SR-BI) is known to mediate cellular uptake of cholesterol from high density lipoprotein particles and is particularly abundant in liver and steroidogenic tissues. In addition, SR-BI expression in the enterocyte brush border has also been reported but...... fat, SR-BI is endocytosed from the enterocyte brush border and accumulates in cytoplasmic lipid droplets. Internalisation of the receptor occurs mainly by clathrin coated pits rather than by a caveolae/lipid raft based mechanism....

  12. Nosocomial pathogens

    African Journals Online (AJOL)

    remains an important problem in intensive care units. Hospital wards had been shown to act as reservoirs of pathogenic microorganisms associated with infection. To assess the prevalence of pathogenic organisms in the environment of the neonatal unit, 92 swabs were randomly collected from cots, incubators and various ...

  13. Cinnamon extract attenuates TNF-alpha-induced intestinal lipoprotein ApoB48 overproduction by regulating inflammatory, insulin, and lipoprotein pathways in enterocytes

    Science.gov (United States)

    We evaluated whether a water extract of cinnamon (CE = Cinnulin PF®) attenuates the dyslipidemia induced by TNF-alpha in Triton WR-1339-treated hamsters, and whether CE inhibited the over-secretion of apoB48-induced by TNF-alpha in enterocytes in a 35S-labelling study. In vivo, oral treatment with C...

  14. Molecular evidence and physiological characterization of iron absorption in isolated enterocytes of rainbow trout (Oncorhynchus mykiss): Implications for dietary cadmium and lead absorption

    International Nuclear Information System (INIS)

    Kwong, Raymond W.M.; Andres, Jose A.; Niyogi, Som

    2010-01-01

    Recent studies suggested the probable involvement of an apical iron (Fe 2+ ) transporter, the divalent metal transporter-1 (DMT1), in the uptake of several divalent metals in fish. The present study examined the gastrointestinal expression of the DMT1 gene, and investigated the kinetics of Fe 2+ uptake and its interactions with cadmium and lead in isolated enterocytes of freshwater rainbow trout (Oncorhynchus mykiss). The expressions of two DMT1 isoforms (Nramp-β and -γ) were recorded along the entire gastrointestinal tract of fish as well as in the enterocytes. Fe 2+ uptake in isolated enterocytes was saturable and sensitive to the proton gradient and membrane potential, suggesting DMT1-mediated transport. Both cadmium and lead inhibited Fe 2+ uptake in isolated enterocytes in a concentration-dependent manner, and lead appeared to be a stronger inhibitor than cadmium. The kinetic characterization of Fe 2+ uptake revealed that the apparent affinity of uptake was significantly decreased (increased K m ) in the presence of either cadmium or lead, whereas the maximum uptake rate (J max ) remained unchanged-indicating that the interaction between Fe 2+ and cadmium or lead is competitive in nature. Overall, our study suggests that the uptake of dietary cadmium and lead may occur via the iron-transporting pathway in fish.

  15. Molecular evidence and physiological characterization of iron absorption in isolated enterocytes of rainbow trout (Oncorhynchus mykiss): Implications for dietary cadmium and lead absorption

    Energy Technology Data Exchange (ETDEWEB)

    Kwong, Raymond W.M. [Toxicology Centre, University of Saskatchewan, Saskatoon, SK., S7N 5B3 (Canada); Andres, Jose A. [Department of Biology, University of Saskatchewan, Saskatoon, SK., S7N 5E2 (Canada); Niyogi, Som, E-mail: som.niyogi@usask.ca [Department of Biology, University of Saskatchewan, Saskatoon, SK., S7N 5E2 (Canada)

    2010-09-01

    Recent studies suggested the probable involvement of an apical iron (Fe{sup 2+}) transporter, the divalent metal transporter-1 (DMT1), in the uptake of several divalent metals in fish. The present study examined the gastrointestinal expression of the DMT1 gene, and investigated the kinetics of Fe{sup 2+} uptake and its interactions with cadmium and lead in isolated enterocytes of freshwater rainbow trout (Oncorhynchus mykiss). The expressions of two DMT1 isoforms (Nramp-{beta} and -{gamma}) were recorded along the entire gastrointestinal tract of fish as well as in the enterocytes. Fe{sup 2+} uptake in isolated enterocytes was saturable and sensitive to the proton gradient and membrane potential, suggesting DMT1-mediated transport. Both cadmium and lead inhibited Fe{sup 2+} uptake in isolated enterocytes in a concentration-dependent manner, and lead appeared to be a stronger inhibitor than cadmium. The kinetic characterization of Fe{sup 2+} uptake revealed that the apparent affinity of uptake was significantly decreased (increased K{sub m}) in the presence of either cadmium or lead, whereas the maximum uptake rate (J{sub max}) remained unchanged-indicating that the interaction between Fe{sup 2+} and cadmium or lead is competitive in nature. Overall, our study suggests that the uptake of dietary cadmium and lead may occur via the iron-transporting pathway in fish.

  16. Deep-apical tubules: dynamic lipid-raft microdomains in the brush-border region of enterocytes

    DEFF Research Database (Denmark)

    Hansen, Gert H; Pedersen, Jens; Niels-Christiansen, Lise-Lotte

    2003-01-01

    microdomains. Deep-apical tubules were positioned close to the actin rootlets of adjacent microvilli in the terminal web region, which had a diameter of 50-100 nm, and penetrated up to 1 microm into the cytoplasm. Markers for transcytosis, IgA and the polymeric immunoglobulin receptor, as well as the resident...... lipid raft-containing compartments, but little is otherwise known about these raft microdomains. We therefore studied in closer detail apical lipid-raft compartments in enterocytes by immunogold electron microscopy and biochemical analyses. Novel membrane structures, deep-apical tubules, were visualized...... brush-border enzyme aminopeptidase N, were present in these deep-apical tubules. We propose that deep-apical tubules are a specialized lipid-raft microdomain in the brush-border region functioning as a hub in membrane trafficking at the brush border. In addition, the sensitivity to cholesterol depletion...

  17. Effacement énonciatif et doxa dans le discours théorique : l’exemple de Julia Kristeva The erasement of subjectivity and doxa in theoretical discourse: the case of Julia Kristeva

    Directory of Open Access Journals (Sweden)

    François Provenzano

    2010-10-01

    Full Text Available Cet article entend contribuer à la réflexion menée sur les phénomènes d’effacement énonciatif, en particulier dans le discours théorique. L’approche se veut inséparablement rhétorique et socio-historique et porte sur un corpus composé des principaux articles publiés par Julia Kristeva dans les années 1960. Ceux-ci sont contrastés avec des interventions ultérieures de la théoricienne, répondant à d’autres enjeux et stratégies. Les effets construits par l’effacement énonciatif sont envisagés comme des opérations sur la doxa, orientées par un contrat rhétorique. Cette notion, située à l’intersection du socio-historique et du discursif, se veut un outil complémentaire pour l’analyse de l’efficace des discours dans un état de société.This paper tackles the issue of enunciative effacement, particularly in theoretical discourse. The approach is both rhetorical and socio-historical, as it focuses on texts published by Julia Kristeva in the sixties and contrasts them with more recent Kristeva speeches, corresponding to other issues and strategies. The effects brought about by enunciative effacement are considered as operations on doxa, which are oriented by a rhetorical contract. This notion, both socio-historical and rhetorical, provides a tool for analyzing the efficiency of discourses in a given state of society.

  18. Organic Cation Transporter 1 (OCT1/mOct1) Is Localized in the Apical Membrane of Caco-2 Cell Monolayers and Enterocytes

    Science.gov (United States)

    Han, Tianxiang (Kevin); Everett, Ruth S.; Proctor, William R.; Ng, Chee M.; Costales, Chester L.; Brouwer, Kim L. R.

    2013-01-01

    Organic cation transporters (OCTs) are members of the solute carrier 22 family of transporter proteins that are involved in absorption, distribution, and excretion of organic cations. OCT3 is localized in the apical (AP) membrane of enterocytes, but the literature is ambiguous about OCT1 (mOct1) localization, with some evidence suggesting a basolateral (BL) localization in human and mouse enterocytes. This is contrary to our preliminary findings showing AP localization of OCT1 in Caco-2 cell monolayers, an established model of human intestinal epithelium. Therefore, this study aims at determining the localization of OCT1 (mOct1) in Caco-2 cells, and human and mouse enterocytes. Functional studies using OCT1-specific substrate pentamidine showed transporter-mediated AP but not BL uptake in Caco-2 cells and human and mouse intestinal tissues. OCT1 inhibition decreased AP uptake of pentamidine by ∼50% in all three systems with no effect on BL uptake. A short hairpin RNA-mediated OCT1 knockdown in Caco-2 cells decreased AP uptake of pentamidine by ∼50% but did not alter BL uptake. Immunostaining and confocal microscopy in all three systems confirmed AP localization of OCT1 (mOct1). Our studies unequivocally show AP membrane localization of OCT1 (mOct1) in Caco-2 cells and human and mouse intestine. These results are highly significant as they will require reinterpretation of previous drug disposition and drug-drug interaction studies where conclusions were drawn assuming BL localization of OCT1 in enterocytes. Most importantly, these results will require revision of the regulatory guidance for industry in the United States and elsewhere because it has stated that OCT1 is basolaterally localized in enterocytes. PMID:23680637

  19. Analytical microscopy observations of rat enterocytes after oral administration of soluble salts of lanthanides, actinides and elements of group III-A of the periodic chart.

    Science.gov (United States)

    Floren, C; Tekaya, L; Escaig, F; Labejof, L; Mouthon, G; Galle, P

    2001-05-01

    The behavior in the intestinal barrier of nine elements (three of the group III-A, four lanthanides and two actinides), absorbed as soluble salts, has been studied by two microanalytical methods: electron probe X-ray micro analysis (EPMA) and secondary ion mass spectrometry (SIMS). It has been shown that the three elements of group III-A, aluminium, gallium and indium; and the four lanthanides, lanthanum, cerium, europium and thulium, are selectively concentrated and precipitated as non-soluble form in enterocytes of proximal part of the intestinal tract. SIMS microscopy has shown that these elements are concentrated as a number of submicroscopic precipitates, most of them localized in the apical part of the duodenum enterocytes, where they are observed from one hour to 48 hr after a single intragastric administration. No precipitate is observed after three days. It is suggested that this mechanism of local concentration limits the diffusion of these elements through the digestive barrier, some of them being toxic and none of them having a recognized physiological role. Additionally, the precipitation in duodenal enterocytes, the life time of which is on the order of 2-3 days, allows the elements absorbed as soluble form to be eliminated as a non-soluble form in the digestive lumen along with the desquamation of the apoptotic enterocytes. The intracytoplasmic localization of the precipitates are supposed to be the lysosomes although no direct evidence could be given here due to the very small sizes of the lysosomes of enterocytes. The same results were not observed with the two studied actinides. After administration of thorium, only some very sparse microprecipitates could be observed in intestinal mucosa and, after administration of uranium, no precipitates were observed with the exception of some in the conjunctive part of the duodenal villi.

  20. The role of cyclooxygenase-1 and cyclooxygenase-2 in lipopolysaccharide and interleukin-1 stimulated enterocyte prostanoid formation

    Directory of Open Access Journals (Sweden)

    W. E. Longo

    1998-01-01

    Full Text Available Lipopolysaccharide is an inflammatory agent and interleukin-1 is a cytokine. Their pro-inflammatory effects may be mediated by prostanoids produced by inducible cyclooxygenase-2. The aim of this study was to determine the prostanoids produced by lipopolysaccharide and interleukin-1 stimulated enterocytes through the cyclooxygenase-1 and 2 pathways. Cultured enterocytes were stimulated with lipopolysaccharide or interleukin-1 β with and without cyclooxygenase inhibitors. Low concentrations of indomethacin and valerylsalicylic acid (VSA were evaluated as cyclooxygenase-1 inhibitors and their effects compared with the effects of a specific cyclooxygenase-2 inhibitor, SC-58125. Prostaglandin E2 , 6-keto prostaglandin F1α , prostaglandin D2 and leukotriene B4 levels were determined by radio immunoassay. Immunoblot analysis using isoformspecific antibodies showed that the inducible cyclooxygenase enzyme (COX-2 was expressed by 4 h in LPS and IL-1β treated cells while the constitutive COX-1 remained unaltered in its expression. Interleukin-1β and lipopolysaccharide stimulated the formation of all prostanoids compared with untreated cells, but failed to stimulate leukotriene B4. Indomethacin at 20 μ M concentration, and VSA inhibited lipopolysaccharide and interleukin 1β stimulated prostaglandin E2 , but not 6-keto prostaglandin F1α formation. SC-58125 inhibited lipopolysaccharide and interleukin-1β stimulated 6-keto prostaglandin F1α but not prostaglandin E2 release. The specific cyclooxygenase-2 inhibitor also inhibited lipopolysaccharide produced prostaglandin D2 but not interleukin-1β stimulated prostaglandin D2 While SC-58125 inhibited basal 6-keto prostaglandin-F1α formation it significantly increased basal prostaglandin E2 and prostaglandin D2 formation. As SC-58125 inhibited lipopolysaccharide and interleukin-1β induced 6-keto prostaglandin F1α production but not prostaglandin E2 production, it suggests that these agents stimulate

  1. Differential Expression of the Activator Protein 1 Transcription Factor Regulates Interleukin-1ß Induction of Interleukin 6 in the Developing Enterocyte.

    Directory of Open Access Journals (Sweden)

    Catherine M Cahill

    Full Text Available The innate immune response is characterized by activation of transcription factors, nuclear factor kappa B and activator protein-1 and their downstream targets, the pro-inflammatory cytokines including interleukin 1β and interleukin 6. Normal development of this response in the intestine is critical to survival of the human neonate and delays can cause the onset of devastating inflammatory diseases such as necrotizing enterocolitis. Previous studies have addressed the role of nuclear factor kappa B in the development of the innate immune response in the enterocyte, however despite its central role in the control of multiple pro-inflammatory cytokine genes, little is known on the role of Activator Protein 1 in this response in the enterocyte. Here we show that the canonical Activator Protein 1 members, cJun and cFos and their upstream kinases JNK and p38 play an essential role in the regulation of interleukin 6 in the immature enterocyte. Our data supports a model whereby the cFos/cJun heterodimer and the more potent cJun homodimer downstream of JNK are replaced by less efficient JunD containing dimers, contributing to the decreased responsiveness to interleukin 1β and decreased interleukin 6 secretion observed in the mature enterocyte. The tissue specific expression of JunB in colonocytes and colon derived tissues together with its ability to repress Interleukin-1β induction of an Interleukin-6 gene reporter in the NCM-460 colonocyte suggests that induction of JunB containing dimers may offer an attractive therapeutic strategy for the control of IL-6 secretion during inflammatory episodes in this area of the intestine.

  2. Modeling of drug-mediated CYP3A4 induction by using human iPS cell-derived enterocyte-like cells

    International Nuclear Information System (INIS)

    Negoro, Ryosuke; Takayama, Kazuo; Nagamoto, Yasuhito; Sakurai, Fuminori; Tachibana, Masashi; Mizuguchi, Hiroyuki

    2016-01-01

    Many drugs have potential to induce the expression of drug-metabolizing enzymes, particularly cytochrome P450 3A4 (CYP3A4), in small intestinal enterocytes. Therefore, a model that can accurately evaluate drug-mediated CYP3A4 induction is urgently needed. In this study, we overlaid Matrigel on the human induced pluripotent stem cells-derived enterocyte-like cells (hiPS-ELCs) to generate the mature hiPS-ELCs that could be applied to drug-mediated CYP3A4 induction test. By overlaying Matrigel in the maturation process of enterocyte-like cells, the gene expression levels of intestinal markers (VILLIN, sucrase-isomaltase, intestine-specific homeobox, caudal type homeobox 2, and intestinal fatty acid-binding protein) were enhanced suggesting that the enterocyte-like cells were maturated by Matrigel overlay. The percentage of VILLIN-positive cells in the hiPS-ELCs found to be approximately 55.6%. To examine the CYP3A4 induction potential, the hiPS-ELCs were treated with various drugs. Treatment with dexamethasone, phenobarbital, rifampicin, or 1α,25-dihydroxyvitamin D3 resulted in 5.8-fold, 13.4-fold, 9.8-fold, or 95.0-fold induction of CYP3A4 expression relative to that in the untreated controls, respectively. These results suggest that our hiPS-ELCs would be a useful model for CYP3A4 induction test. - Highlights: • The hiPS-ELCs were matured by Matrigel overlay. • The hiPS-ELCs expressed intestinal nuclear receptors, such as PXR, GR and VDR. • The hiPS-ELC is a useful model for the drug-mediated CYP3A4 induction test.

  3. Modeling of drug-mediated CYP3A4 induction by using human iPS cell-derived enterocyte-like cells

    Energy Technology Data Exchange (ETDEWEB)

    Negoro, Ryosuke [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Takayama, Kazuo [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); The Keihanshin Consortium for Fostering the Next Generation of Global Leaders in Research (K-CONNEX), Kyoto University, Kyoto 606-8302 (Japan); Laboratory of Hepatocyte Regulation, National Institute of Biomedical Innovation, Health and Nutrition, Osaka 567-0085 (Japan); Nagamoto, Yasuhito [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Laboratory of Hepatocyte Regulation, National Institute of Biomedical Innovation, Health and Nutrition, Osaka 567-0085 (Japan); Sakurai, Fuminori [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Laboratory of Regulatory Sciences for Oligonucleotide Therapeutics, Clinical Drug Development Project, Graduate School of Pharmaceutical Sciences, Osaka University Osaka 565-0871 (Japan); Tachibana, Masashi [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Mizuguchi, Hiroyuki, E-mail: mizuguch@phs.osaka-u.ac.jp [Laboratory of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871 (Japan); Laboratory of Hepatocyte Regulation, National Institute of Biomedical Innovation, Health and Nutrition, Osaka 567-0085 (Japan); Global Center for Medical Engineering and Informatics, Osaka University, Osaka 565-0871 (Japan)

    2016-04-15

    Many drugs have potential to induce the expression of drug-metabolizing enzymes, particularly cytochrome P450 3A4 (CYP3A4), in small intestinal enterocytes. Therefore, a model that can accurately evaluate drug-mediated CYP3A4 induction is urgently needed. In this study, we overlaid Matrigel on the human induced pluripotent stem cells-derived enterocyte-like cells (hiPS-ELCs) to generate the mature hiPS-ELCs that could be applied to drug-mediated CYP3A4 induction test. By overlaying Matrigel in the maturation process of enterocyte-like cells, the gene expression levels of intestinal markers (VILLIN, sucrase-isomaltase, intestine-specific homeobox, caudal type homeobox 2, and intestinal fatty acid-binding protein) were enhanced suggesting that the enterocyte-like cells were maturated by Matrigel overlay. The percentage of VILLIN-positive cells in the hiPS-ELCs found to be approximately 55.6%. To examine the CYP3A4 induction potential, the hiPS-ELCs were treated with various drugs. Treatment with dexamethasone, phenobarbital, rifampicin, or 1α,25-dihydroxyvitamin D3 resulted in 5.8-fold, 13.4-fold, 9.8-fold, or 95.0-fold induction of CYP3A4 expression relative to that in the untreated controls, respectively. These results suggest that our hiPS-ELCs would be a useful model for CYP3A4 induction test. - Highlights: • The hiPS-ELCs were matured by Matrigel overlay. • The hiPS-ELCs expressed intestinal nuclear receptors, such as PXR, GR and VDR. • The hiPS-ELC is a useful model for the drug-mediated CYP3A4 induction test.

  4. Endocytosis-inducer adhesins produced by enteropathogenic serogroups of Escherichia coli participate on bacterial attachment to infant enterocytes

    Directory of Open Access Journals (Sweden)

    João Ramos Costa Andrade

    1987-03-01

    Full Text Available Enteropathogenic E. coli (EPEC infection of Hep-2 cells preoceeds through bacterial attachment to cell surface and internalization of adhered bacteria. EPEC attachment is a prerequisite for cell infection and is mediated by adhesins that recognize carbohydrate-containing receptors on cell membrane. Such endocytosis-inducer adhesins (EIA also promote EPEC binding to infant enterocytes, suggesting that EIA may have an important role on EPEC gastroenteritis.A infecção de células Hep-2 por E. coli enteropatogênicas (ECEP implica na aderência bacteriana e posterior interiorização dos microrganismos aderidos por um mecanismo de endocitose. A aderência das ECEP é pré-requisito para a infecção e é mediada por adesinas que reconhecem receptores inibidos por certas oses na membrana celular. Tais "adesinas indutoras da endocitose" (AIE também promovem a ligação bacteriana a enterócitos obtidos do intestino delgado de lactente, sugerindo que as AIE possam desempenhar algum papel nas diarréias causadas por ECEP.

  5. Citrobacter rodentium is an unstable pathogen showing evidence of significant genomic flux.

    Directory of Open Access Journals (Sweden)

    Nicola K Petty

    2011-04-01

    Full Text Available Citrobacter rodentium is a natural mouse pathogen that causes attaching and effacing (A/E lesions. It shares a common virulence strategy with the clinically significant human A/E pathogens enteropathogenic E. coli (EPEC and enterohaemorrhagic E. coli (EHEC and is widely used to model this route of pathogenesis. We previously reported the complete genome sequence of C. rodentium ICC168, where we found that the genome displayed many characteristics of a newly evolved pathogen. In this study, through PFGE, sequencing of isolates showing variation, whole genome transcriptome analysis and examination of the mobile genetic elements, we found that, consistent with our previous hypothesis, the genome of C. rodentium is unstable as a result of repeat-mediated, large-scale genome recombination and because of active transposition of mobile genetic elements such as the prophages. We sequenced an additional C. rodentium strain, EX-33, to reveal that the reference strain ICC168 is representative of the species and that most of the inactivating mutations were common to both isolates and likely to have occurred early on in the evolution of this pathogen. We draw parallels with the evolution of other bacterial pathogens and conclude that C. rodentium is a recently evolved pathogen that may have emerged alongside the development of inbred mice as a model for human disease.

  6. Foodborne pathogens

    Directory of Open Access Journals (Sweden)

    Thomas Bintsis

    2017-06-01

    Full Text Available Foodborne pathogens are causing a great number of diseases with significant effects on human health and economy. The characteristics of the most common pathogenic bacteria (Bacillus cereus, Campylobacter jejuni, Clostridium botulinum, Clostridium perfringens, Cronobacter sakazakii, Esherichia coli, Listeria monocytogenes, Salmonella spp., Shigella spp., Staphylococccus aureus, Vibrio spp. and Yersinia enterocolitica, viruses (Hepatitis A and Noroviruses and parasites (Cyclospora cayetanensis, Toxoplasma gondii and Trichinella spiralis, together with some important outbreaks, are reviewed. Food safety management systems based on to classical hazard-based approach has been proved to be inefficient, and risk-based food safety approach is now suggested from leading researchers and organizations. In this context, a food safety management system should be designed in a way to estimate the risks to human health from food consumption and to identify, select and implement mitigation strategies in order to control and reduce these risks. In addition, the application of suitable food safety education programs for all involved people in the production and consumption of foods is suggested.

  7. MicroRNA mir-16 is anti-proliferative in enterocytes and exhibits diurnal rhythmicity in intestinal crypts

    Energy Technology Data Exchange (ETDEWEB)

    Balakrishnan, Anita, E-mail: anita.balakrishnan@doctors.org.uk [Department of Surgery, Brigham and Women' s Hospital, Boston, MA 02115 (United States); Department of Surgery, Harvard Medical School, Boston, MA 02115 (United States); School of Clinical Sciences, Division of Gastroenterology, University of Liverpool, Liverpool L69 3GE (United Kingdom); Stearns, Adam T. [Department of Surgery, Brigham and Women' s Hospital, Boston, MA 02115 (United States); Department of Surgery, Harvard Medical School, Boston, MA 02115 (United States); Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 2JD (United Kingdom); Park, Peter J. [Department of Medicine, Brigham and Women' s Hospital, Boston, MA 02115 (United States); Harvard Medical School, Center for Biomedical Informatics, Boston, MA 02115 (United States); Dreyfuss, Jonathan M. [Department of Medicine, Brigham and Women' s Hospital, Boston, MA 02115 (United States); Ashley, Stanley W. [Department of Surgery, Brigham and Women' s Hospital, Boston, MA 02115 (United States); Department of Surgery, Harvard Medical School, Boston, MA 02115 (United States); Rhoads, David B. [Department of Surgery, Harvard Medical School, Boston, MA 02115 (United States); Pediatric Endocrine Unit, MassGeneral Hospital for Children, Boston, MA 02114 (United States); Tavakkolizadeh, Ali, E-mail: atavakkoli@partners.org [Department of Surgery, Brigham and Women' s Hospital, Boston, MA 02115 (United States); Department of Surgery, Harvard Medical School, Boston, MA 02115 (United States)

    2010-12-10

    Background and aims: The intestine exhibits profound diurnal rhythms in function and morphology, in part due to changes in enterocyte proliferation. The regulatory mechanisms behind these rhythms remain largely unknown. We hypothesized that microRNAs are involved in mediating these rhythms, and studied the role of microRNAs specifically in modulating intestinal proliferation. Methods: Diurnal rhythmicity of microRNAs in rat jejunum was analyzed by microarrays and validated by qPCR. Temporal expression of diurnally rhythmic mir-16 was further quantified in intestinal crypts, villi, and smooth muscle using laser capture microdissection and qPCR. Morphological changes in rat jejunum were assessed by histology and proliferation by immunostaining for bromodeoxyuridine. In IEC-6 cells stably overexpressing mir-16, proliferation was assessed by cell counting and MTS assay, cell cycle progression and apoptosis by flow cytometry, and cell cycle gene expression by qPCR and immunoblotting. Results: mir-16 peaked 6 hours after light onset (HALO 6) with diurnal changes restricted to crypts. Crypt depth and villus height peaked at HALO 13-14 in antiphase to mir-16. Overexpression of mir-16 in IEC-6 cells suppressed specific G1/S regulators (cyclins D1-3, cyclin E1 and cyclin-dependent kinase 6) and produced G1 arrest. Protein expression of these genes exhibited diurnal rhythmicity in rat jejunum, peaking between HALO 11 and 17 in antiphase to mir-16. Conclusions: This is the first report of circadian rhythmicity of specific microRNAs in rat jejunum. Our data provide a link between anti-proliferative mir-16 and the intestinal proliferation rhythm and point to mir-16 as an important regulator of proliferation in jejunal crypts. This function may be essential to match proliferation and absorptive capacity with nutrient availability.

  8. MicroRNA mir-16 is anti-proliferative in enterocytes and exhibits diurnal rhythmicity in intestinal crypts

    International Nuclear Information System (INIS)

    Balakrishnan, Anita; Stearns, Adam T.; Park, Peter J.; Dreyfuss, Jonathan M.; Ashley, Stanley W.; Rhoads, David B.; Tavakkolizadeh, Ali

    2010-01-01

    Background and aims: The intestine exhibits profound diurnal rhythms in function and morphology, in part due to changes in enterocyte proliferation. The regulatory mechanisms behind these rhythms remain largely unknown. We hypothesized that microRNAs are involved in mediating these rhythms, and studied the role of microRNAs specifically in modulating intestinal proliferation. Methods: Diurnal rhythmicity of microRNAs in rat jejunum was analyzed by microarrays and validated by qPCR. Temporal expression of diurnally rhythmic mir-16 was further quantified in intestinal crypts, villi, and smooth muscle using laser capture microdissection and qPCR. Morphological changes in rat jejunum were assessed by histology and proliferation by immunostaining for bromodeoxyuridine. In IEC-6 cells stably overexpressing mir-16, proliferation was assessed by cell counting and MTS assay, cell cycle progression and apoptosis by flow cytometry, and cell cycle gene expression by qPCR and immunoblotting. Results: mir-16 peaked 6 hours after light onset (HALO 6) with diurnal changes restricted to crypts. Crypt depth and villus height peaked at HALO 13-14 in antiphase to mir-16. Overexpression of mir-16 in IEC-6 cells suppressed specific G1/S regulators (cyclins D1-3, cyclin E1 and cyclin-dependent kinase 6) and produced G1 arrest. Protein expression of these genes exhibited diurnal rhythmicity in rat jejunum, peaking between HALO 11 and 17 in antiphase to mir-16. Conclusions: This is the first report of circadian rhythmicity of specific microRNAs in rat jejunum. Our data provide a link between anti-proliferative mir-16 and the intestinal proliferation rhythm and point to mir-16 as an important regulator of proliferation in jejunal crypts. This function may be essential to match proliferation and absorptive capacity with nutrient availability.

  9. The Regulatory Role of MeAIB in Protein Metabolism and the mTOR Signaling Pathway in Porcine Enterocytes

    Directory of Open Access Journals (Sweden)

    Yulong Tang

    2018-03-01

    Full Text Available Amino acid transporters play an important role in cell growth and metabolism. MeAIB, a transporter-selective substrate, often represses the adaptive regulation of sodium-coupled neutral amino acid transporter 2 (SNAT2, which may act as a receptor and regulate cellular amino acid contents, therefore modulating cellular downstream signaling. The aim of this study was to investigate the effects of MeAIB to SNAT2 on cell proliferation, protein turnover, and the mammalian target of rapamycin (mTOR signaling pathway in porcine enterocytes. Intestinal porcine epithelial cells (IPEC-J2 cells were cultured in a high-glucose Dulbecco’s modified Eagle’s (DMEM-H medium with 0 or 5 mmoL/L System A amino acid analogue (MeAIB for 48 h. Cells were collected for analysis of proliferation, cell cycle, protein synthesis and degradation, intracellular free amino acids, and the expression of key genes involved in the mTOR signaling pathway. The results showed that SNAT2 inhibition by MeAIB depleted intracellular concentrations of not only SNAT2 amino acid substrates but also of indispensable amino acids (methionine and leucine, and suppressed cell proliferation and impaired protein synthesis. MeAIB inhibited mTOR phosphorylation, which might be involved in three translation regulators, EIF4EBP1, IGFBP3, and DDIT4 from PCR array analysis of the 84 genes related to the mTOR signaling pathway. These results suggest that SNAT2 inhibition treated with MeAIB plays an important role in regulating protein synthesis and mTOR signaling, and provide some information to further clarify its roles in the absorption of amino acids and signal transduction in the porcine small intestine.

  10. Augmented internalisation of ferroportin to late endosomes impairs iron uptake by enterocyte-like IEC-6 cells.

    Science.gov (United States)

    Oates, Phillip S; Thomas, Carla

    2005-08-01

    Absorption of iron occurs by duodenal enterocytes, involving uptake by the divalent metal transporter-1 (DMT1) and release by ferroportin. Ferroportin responds to the hepatocyte-produced 25-amino-acid-peptide hepcidin-25 by undergoing internalisation to late endosomes that impair iron release. Ferroportin is also expressed on the apical membrane of polarised Caco-2 cells, rat intestinal cells and in IEC-6 cells (an intestinal epithelial cell line). A blocking antibody to ferroportin also impairs the uptake, but not the release, of iron. In this study IEC-6 cells were used to study the mechanism of impairment or recovery from impairment produced by the blocking antibody and the fate of DMT1 and ferroportin. Uptake of 1 muM Fe(II) was studied by adding the antibody from time 0 and after adding or removing the antibody once a steady state had been reached. Surface binding, maximum iron transport rate V(max) and transporter affinity (K(m)) were measured after impairment of iron uptake. Ferroportin and DMT1 distribution were assessed by immunofluorescence microscopy. Antibody-mediated impairment, or recovery from impairment, of Fe(II) uptake occurred within minutes. Impairment was lost when the antibody was combined with the immunizing peptide. DMT1 and ferroportin undergo internalisation to late endosomes and, in the presence of the antibody, augmented internalisation of DMT1 and ferroportin caused swelling of late endosomes. Surface binding of Fe(II) and iron transport V(max) were reduced by 50%, indicating that the antibody removed membrane-bound DMT1. The ferroportin antibody induced rapid turnover of membrane ferroportin and DMT1 and its internalisation to late endosomes, resulting in impaired Fe(II) uptake.

  11. Activation of peroxisome proliferator-activated receptor-{alpha} (PPAR{alpha}) suppresses postprandial lipidemia through fatty acid oxidation in enterocytes

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Rino [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Takahashi, Nobuyuki, E-mail: nobu@kais.kyoto-u.ac.jp [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Murota, Kaeko [Department of Life Science, School of Science and Engineering, Kinki University, Osaka 770-8503 (Japan); Yamada, Yuko [Laboratory of Physiological Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Niiya, Saori; Kanzaki, Noriyuki; Murakami, Yoko [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Moriyama, Tatsuya [Department of Applied Cell Biology, Graduate School of Agriculture, Kinki University, Nara 631-8505 (Japan); Goto, Tsuyoshi; Kawada, Teruo [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan)

    2011-06-24

    Highlights: {yields} PPAR{alpha} activation increased mRNA expression levels of fatty acid oxidation-related genes in human intestinal epithelial Caco-2 cells. {yields} PPAR{alpha} activation also increased oxygen consumption rate and CO{sub 2} production and decreased secretion of triglyceride and ApoB from Caco-2 cells. {yields} Orally administration of bezafibrate increased mRNA expression levels of fatty acid oxidation-related genes and CO{sub 2} production in small intestinal epithelial cells. {yields} Treatment with bezafibrate decreased postprandial serum concentration of triglyceride after oral injection of olive oil in mice. {yields} It suggested that intestinal lipid metabolism regulated by PPAR{alpha} activation suppresses postprandial lipidemia. -- Abstract: Activation of peroxisome proliferator-activated receptor (PPAR)-{alpha} which regulates lipid metabolism in peripheral tissues such as the liver and skeletal muscle, decreases circulating lipid levels, thus improving hyperlipidemia under fasting conditions. Recently, postprandial serum lipid levels have been found to correlate more closely to cardiovascular diseases than fasting levels, although fasting hyperlipidemia is considered an important risk of cardiovascular diseases. However, the effect of PPAR{alpha} activation on postprandial lipidemia has not been clarified. In this study, we examined the effects of PPAR{alpha} activation in enterocytes on lipid secretion and postprandial lipidemia. In Caco-2 enterocytes, bezafibrate, a potent PPAR{alpha} agonist, increased mRNA expression levels of fatty acid oxidation-related genes, such as acyl-CoA oxidase, carnitine palmitoyl transferase, and acyl-CoA synthase, and oxygen consumption rate (OCR) and suppressed secretion levels of both triglycerides and apolipoprotein B into the basolateral side. In vivo experiments revealed that feeding high-fat-diet containing bezafibrate increased mRNA expression levels of fatty acid oxidation-related genes and

  12. The Opportunistic Pathogen Listeria monocytogenes: Pathogenicity and Interaction with the Mucosal Immune System

    Directory of Open Access Journals (Sweden)

    Markus Schuppler

    2010-01-01

    Full Text Available Listeria monocytogenes is an opportunistic foodborne pathogen causing listeriosis, an often fatal infection leading to meningitis, sepsis, or infection of the fetus and abortion in susceptible individuals. It was recently found that the bacterium can also cause acute, self-limiting febrile gastroenteritis in healthy individuals. In the intestinal tract, L. monocytogenes penetrates the mucosa directly via enterocytes, or indirectly via invasion of Peyer’s patches. Animal models for L. monocytogenes infection have provided many insights into the mechanisms of pathogenesis, and the development of new model systems has allowed the investigation of factors that influence adaptation to the gastrointestinal environment as well as adhesion to and invasion of the intestinal mucosa. The mucosal surfaces of the gastrointestinal tract are permanently exposed to an enormous antigenic load derived from the gastrointestinal microbiota present in the human bowel. The integrity of the important epithelial barrier is maintained by the mucosal immune system and its interaction with the commensal flora via pattern recognition receptors (PRRs. Here, we discuss recent advances in our understanding of the interaction of L. monocytogenes with the host immune system that triggers the antibacterial immune responses on the mucosal surfaces of the human gastrointestinal tract.

  13. Oleic Acid Uptake Reveals the Rescued Enterocyte Phenotype of Colon Cancer Caco-2 by HT29-MTX Cells in Co-Culture Mode

    Science.gov (United States)

    Berger, Emmanuelle; Nassra, Merian; Atgié, Claude; Plaisancié, Pascale; Géloën, Alain

    2017-01-01

    Gastrointestinal epithelium is the unique route for nutrients and for many pharmaceuticals to enter the body. The present study aimed to analyze precisely whether co-culture of two colon cancer cell lines, mucus-producing cells HT29-MTX and enterocyte-like Caco-2 cells, ameliorate differentiation into an in vitro intestinal barrier model and the signaling pathways involved. Differentiated Caco-2 cells gene datasets were compared first to intestinal or cancer phenotypes and second to signaling pathway gene datasets. Experimental validations were performed in real-time experiments, immunochemistry, and gene expression analyses on Caco-2 versus co-cultures of Caco-2 and HT29-MTX (10%) cells. Partial maintenance of cancer-cell phenotype in differentiated Caco-2 cells was confirmed and fatty acids merged as potential regulators of cancer signaling pathways. HT29-MTX cells induced morphological changes in Caco-2 cells, slightly increased their proliferation rate and profoundly modified gene transcription of phenotype markers, fatty acid receptors, intracellular transporters, and lipid droplet components as well as functional responses to oleic acid. In vitro, enterocyte phenotype was rescued partially by co-culture of cancer cells with goblet cells and completed through oleic acid interaction with signaling pathways dysregulated in cancer cells. PMID:28726765

  14. Emerging Pathogens Initiative (EPI)

    Data.gov (United States)

    Department of Veterans Affairs — The Emerging Pathogens Initiative (EPI) database contains emerging pathogens information from the local Veterans Affairs Medical Centers (VAMCs). The EPI software...

  15. Toxicological effects of pet food ingredients on canine bone marrow-derived mesenchymal stem cells and enterocyte-like cells.

    Science.gov (United States)

    Ortega, M T; Jeffery, B; Riviere, J E; Monteiro-Riviere, N A

    2016-02-01

    We developed an in vitro method to assess pet food ingredients safety. Canine bone marrow-derived mesenchymal stem cells (BMSC) were differentiated into enterocyte-like cells (ELC) to assess toxicity in cells representing similar patterns of exposure in vivo. The toxicological profile of clove leave oil, eugenol, guanosine monophosphate (GMP), GMP + inosine monophosphate, sorbose, ginger root extract, cinnamon bark oil, cinnamaldehyde, thyme oil, thymol and citric acid was assessed in BMSC and ELC. The LC50 for GMP + inosine monophosphate was 59.42 ± 0.90 and 56.7 ± 3.5 mg ml(-1) for BMSC and ELC; 56.84 ± 0.95 and 53.66 ± 1.36 mg ml(-1) for GMP; 0.02 ± 0.001 and 1.25 ± 0.47 mg ml(-1) for citric acid; 0.077 ± 0.002 and 0.037 ± 0.01 mg ml(-1) for cinnamaldehyde; 0.002 ± 0.0001 and 0.002 ± 0.0008 mg ml(-1) for thymol; 0.080 ± 0.003 and 0.059 ± 0.001 mg ml(-1) for thyme oil; 0.111 ± 0.002 and 0.054 ± 0.01 mg ml(-1) for cinnamon bark oil; 0.119 ± 0.0004 and 0.099 ± 0.011 mg ml(-1) for clove leave oil; 0.04 ± 0.001 and 0.028 ± 0.002 mg ml(-1) for eugenol; 2.80 ± 0.11 and 1.75 ± 0.51 mg ml(-1) for ginger root extract; > 200 and 116.78 ± 7.35 mg ml(-1) for sorbose. Lemon grass oil was evaluated at 0.003-0.9 in BMSC and .03-0.9 mg ml(-1) in ELC and its mechanistic effect was investigated. The gene toxicology studies showed regulation of 61% genes in CYP450 pathway, 37% in cholestasis and 33% in immunotoxicity pathways for BMSC. For ELC, 80% for heat shock response, 69% for beta-oxidation and 65% for mitochondrial energy metabolism. In conclusion, these studies provide a baseline against which differential toxicity of dietary feed ingredients can be assessed in vitro for direct effects on canine cells and demonstrate differential toxicity in differentiated cells that represent gastrointestinal epithelial cells

  16. IL-22 Upregulates Epithelial Claudin-2 to Drive Diarrhea and Enteric Pathogen Clearance.

    Science.gov (United States)

    Tsai, Pei-Yun; Zhang, Bingkun; He, Wei-Qi; Zha, Juan-Min; Odenwald, Matthew A; Singh, Gurminder; Tamura, Atsushi; Shen, Le; Sailer, Anne; Yeruva, Sunil; Kuo, Wei-Ting; Fu, Yang-Xin; Tsukita, Sachiko; Turner, Jerrold R

    2017-06-14

    Diarrhea is a host response to enteric pathogens, but its impact on pathogenesis remains poorly defined. By infecting mice with the attaching and effacing bacteria Citrobacter rodentium, we defined the mechanisms and contributions of diarrhea and intestinal barrier loss to host defense. Increased permeability occurred within 2 days of infection and coincided with IL-22-dependent upregulation of the epithelial tight junction protein claudin-2. Permeability increases were limited to small molecules, as expected for the paracellular water and Na + channel formed by claudin-2. Relative to wild-type, claudin-2-deficient mice experienced severe disease, including increased mucosal colonization by C. rodentium, prolonged pathogen shedding, exaggerated cytokine responses, and greater tissue injury. Conversely, transgenic claudin-2 overexpression reduced disease severity. Chemically induced osmotic diarrhea reduced colitis severity and C. rodentium burden in claudin-2-deficient, but not transgenic, mice, demonstrating that claudin-2-mediated protection is the result of enhanced water efflux. Thus, IL-22-induced claudin-2 upregulation drives diarrhea and pathogen clearance. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Onset of transcription of the aminopeptidase N (leukemia antigen CD 13) gene at the crypt/villus transition zone during rabbit enterocyte differentiation

    DEFF Research Database (Denmark)

    Norén, O; Dabelsteen, E; Høyer, P E

    1989-01-01

    The sequence of a cDNA clone (2.82 kbp) of rabbit intestinal aminopeptidase N (CD 13) is reported. Using the corresponding anti-sense RNA probe, the distribution of aminopeptidase N mRNA along the crypt/villus axis of the rabbit small intestine was studied by in situ hybridization....... The aminopeptidase N gene is expressed along the whole length of the villus with a maximum at its base. Expression was not detected in the crypt cells. The distribution of aminopeptidase N mRNA correlates with the presence of active enzyme as monitored by histochemical staining. The results are compatible with onset...... of transcription of the aminopeptidase N gene at the crypt/villus transition zone during the enterocyte differentiation....

  18. Sepsis reveals compartment-specific responses in intestinal proliferation and apoptosis in transgenic mice whose enterocytes re-enter the cell cycle.

    Science.gov (United States)

    Lyons, John D; Klingensmith, Nathan J; Otani, Shunsuke; Mittal, Rohit; Liang, Zhe; Ford, Mandy L; Coopersmith, Craig M

    2017-12-01

    Cell production and death are tightly regulated in the rapidly renewing gut epithelium, with proliferation confined to crypts and apoptosis occurring in villi and crypts. This study sought to determine how stress alters these compartmentalized processes. Wild-type mice made septic via cecal ligation and puncture had decreased crypt proliferation and increased crypt and villus apoptosis. Fabpi -TAg mice expressing large T-antigen solely in villi had ectopic enterocyte proliferation with increased villus apoptosis in unmanipulated animals. Septic fabpi -TAg mice had an unexpected increase in villus proliferation compared with unmanipulated littermates, whereas crypt proliferation was decreased. Cell cycle regulators cyclin D1 and cyclin D2 were decreased in jejunal tissue in septic transgenic mice. In contrast, villus and crypt apoptosis were increased in septic fabpi -TAg mice. To examine the relationship between apoptosis and proliferation in a compartment-specific manner, fabpi -TAg mice were crossed with fabpl -Bcl-2 mice, resulting in expression of both genes in the villus but Bcl-2 alone in the crypt. Septic bi-transgenic animals had decreased crypt apoptosis but had a paradoxical increase in villus apoptosis compared with septic fabpi -TAg mice, associated with decreased proliferation in both compartments. Thus, sepsis unmasks compartment-specific proliferative and apoptotic regulation that is not present under homeostatic conditions.-Lyons, J. D., Klingensmith, N. J., Otani, S., Mittal, R., Liang, Z., Ford, M. L., Coopersmith, C. M. Sepsis reveals compartment-specific responses in intestinal proliferation and apoptosis in transgenic mice whose enterocytes re-enter the cell cycle. © FASEB.

  19. Enhanced transferrin receptor expression by proinflammatory cytokines in enterocytes as a means for local delivery of drugs to inflamed gut mucosa.

    Directory of Open Access Journals (Sweden)

    Efrat Harel

    Full Text Available Therapeutic intervention in inflammatory bowel diseases (IBDs is often associated with adverse effects related to drug distribution into non-diseased tissues, a situation which attracts a rational design of a targeted treatment confined to the inflamed mucosa. Upon activation of immune cells, transferrin receptor (TfR expression increases at their surface. Because TfR is expressed in all cell types we hypothesized that its cell surface levels are regulated also in enterocytes. We, therefore, compared TfR expression in healthy and inflamed human colonic mucosa, as well as healthy and inflamed colonic mucosa of the DNBS-induced rat model. TfR expression was elevated in the colonic mucosa of IBD patients in both the basolateral and apical membranes of the enterocytes. Increased TfR expression was also observed in colonocytes of the induced colitis rats. To explore the underlying mechanism CaCo-2 cells were treated with various proinflammatory cytokines, which increased both TfR expression and transferrin cellular uptake in a mechanism that did not involve hyper proliferation. These findings were then exploited for the design of targetable carrier towards inflamed regions of the colon. Anti-TfR antibodies were conjugated to nano-liposomes. As expected, iron-starved Caco-2 cells internalized anti-TfR immunoliposomes better than controls. Ex vivo binding studies to inflamed mucosa showed that the anti-TfR immunoliposomes accumulated significantly better in the mucosa of DNBS-induced rats than the accumulation of non-specific immunoliposomes. It is concluded that targeting mucosal inflammation can be accomplished by nano-liposomes decorated with anti-TfR due to inflammation-dependent, apical, elevated expression of the receptor.

  20. Detection and characterization of verocytotoxin-producing Escherichia coli by automated 5 ' nuclease PCR assay

    DEFF Research Database (Denmark)

    Nielsen, Eva Møller; Andersen, Marianne Thorup

    2003-01-01

    In recent years increased attention has been focused on infections caused by isolates of verocytotoxin-producing Escherichia coli (VTEC) serotypes other than O157. These non-O157 VTEC isolates are commonly present in food and food production animals. Easy detection, isolation, and characterization...... of hydrophobic-grid membrane filters and DNA probe hybridization. Furthermore, we have developed 5' nuclease PCR assays for the detection of virulence factors typically present in VTEC isolates, including subtypes of three genes of the locus of enterocyte effacement (LEE) pathogenicity island. The 22 assays...

  1. Effect of soy and milk protein-related compounds on Listeria monocytogenes infection in human enterocyte Caco-2 cells and A/J mice.

    Science.gov (United States)

    Kuda, Takashi; Nakamura, Shinsuke; An, Choa; Takahashi, Hajime; Kimura, Bon

    2012-10-15

    Listeria monocytogenes causes listeriosis in humans, mainly through the consumption of ready-to-eat foods such as cheese. Immunocompromised persons, the elderly, and pregnant women and their fetuses or newborns are at the highest risk for the infection. We examined the effects of dietary milk-casein (MC) and soy-protein (SP), and their digested compounds tryptone (TP) and phytone peptone (PP), respectively, on L. monocytogenes invasion and infection in human enterocyte-like Caco-2 cells and A/J mice. Invasion into Caco-2 cells tended to be high with TP. In A/J mice orally infected with L. monocytogenes, viable numbers in the liver and spleen showed a tendency of decreasing with the 20% SP diet compared to the 20% MC diet. SP suppressed the inflammation marker tumour necrosis factor-α in spleen tissue. Furthermore, bacteria lipopolysaccharide (LPS)-stimulated nitric oxide (NO) secretion from murine macrophage RAW 264.7 cells was suppressed by PP more than TP. These results suggest that major dietary proteins might affect infection and inflammation by L. monocytogenes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Hippo, TGF-β, and Src-MAPK pathways regulate transcription of the upd3 cytokine in Drosophila enterocytes upon bacterial infection.

    Science.gov (United States)

    Houtz, Philip; Bonfini, Alessandro; Liu, Xi; Revah, Jonathan; Guillou, Aurélien; Poidevin, Mickael; Hens, Korneel; Huang, Hsin-Yi; Deplancke, Bart; Tsai, Yu-Chen; Buchon, Nicolas

    2017-11-01

    Cytokine signaling is responsible for coordinating conserved epithelial regeneration and immune responses in the digestive tract. In the Drosophila midgut, Upd3 is a major cytokine, which is induced in enterocytes (EC) and enteroblasts (EB) upon oral infection, and initiates intestinal stem cell (ISC) dependent tissue repair. To date, the genetic network directing upd3 transcription remains largely uncharacterized. Here, we have identified the key infection-responsive enhancers of the upd3 gene and show that distinct enhancers respond to various stresses. Furthermore, through functional genetic screening, bioinformatic analyses and yeast one-hybrid screening, we determined that the transcription factors Scalloped (Sd), Mothers against dpp (Mad), and D-Fos are principal regulators of upd3 expression. Our study demonstrates that upd3 transcription in the gut is regulated by the activation of multiple pathways, including the Hippo, TGF-β/Dpp, and Src, as well as p38-dependent MAPK pathways. Thus, these essential pathways, which are known to control ISC proliferation cell-autonomously, are also activated in ECs to promote tissue turnover the regulation of upd3 transcription.

  3. Styrene maleic acid micelles as a nanocarrier system for oral anticancer drug delivery – dual uptake through enterocytes and M-cells

    Directory of Open Access Journals (Sweden)

    Parayath NN

    2015-07-01

    Full Text Available Neha N Parayath,1 Hayley Nehoff,1 Philipp Müller,1 Sebastien Taurin,1 Khaled Greish1,21Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand; 2Department of Oncology, Faculty of Medicine, Suez Canal University, Ismaileya, EgyptAbstract: Drug delivery systems could potentially overcome low bioavailability and gastrointestinal toxicity, which are the major challenges for the development of oral anticancer drugs. Herein, we demonstrate the ability of styrene maleic acid (SMA nanomicelles encapsulating epirubicin to traverse in vitro and ex vivo models of the intestinal epithelium without affecting the tissue integrity. Further, SMA micelles encapsulating a fluorescent dye dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI showed twofold higher accumulation in the liver and spleen, 15-fold higher accumulation in the tumor, and sixfold higher accumulation in the lung as compared with the free DiI, following oral administration in a mice xenograft breast cancer model. Additionally, SMA micelles showed colocalization with microfold (M-cells and accumulation in Peyer’s patches, which together confirms the M-cell mediated uptake and transport of SMA micelles. Our results indicate that SMA micelles, showing dual uptake by enterocytes and M-cells, are a potential tool for safe oral anticancer drug delivery.Keywords: oral delivery, anticancer nanomedicine, enhanced permeability and retention effect, EPR

  4. Protective Effects of Bifidobacterium on Intestinal Barrier Function in LPS-Induced Enterocyte Barrier Injury of Caco-2 Monolayers and in a Rat NEC Model.

    Science.gov (United States)

    Ling, Xiang; Linglong, Peng; Weixia, Du; Hong, Wei

    2016-01-01

    Zonulin protein is a newly discovered modulator which modulates the permeability of the intestinal epithelial barrier by disassembling intercellular tight junctions (TJ). Disruption of TJ is associated with neonatal necrotizing enterocolitis (NEC). It has been shown bifidobacterium could protect the intestinal barrier function and prophylactical administration of bifidobacterium has beneficial effects in NEC patients and animals. However, it is still unknown whether the zonulin is involved in the gut barrier dysfunction of NEC, and the protective mechanisms of bifidobacterium on intestinal barrier function are also not well understood. The present study aims to investigate the effects of bifidobacterium on intestinal barrier function, zonulin regulation, and TJ integrity both in LPS-induced enterocyte barrier injury of Caco-2 monolayers and in a rat NEC model. Our results showed bifidobacterium markedly attenuated the decrease in transepithelial electrical resistance and the increase in paracellular permeability in the Caco-2 monolayers treated with LPS (P zonulin release (P zonulin (P zonulin protein release and improvement of intestinal TJ integrity.

  5. Food-borne pathogens

    International Nuclear Information System (INIS)

    Niemand, J.G.

    1985-01-01

    The Salmonella scare reinforced the importance of never taking chances when it comes to controlling pathogens. The issue has been resolved by radurisation. The article deals with the various pathogens that can effect food and argues the case for radurisation in dealing with them. It also looks at some of the other food products that can be treated using this process

  6. Plant pathogen resistance

    Science.gov (United States)

    Greenberg, Jean T; Jung, Ho Won; Tschaplinski, Timothy

    2012-11-27

    Azelaic acid or its derivatives or analogs induce a robust and a speedier defense response against pathogens in plants. Azelaic acid treatment alone does not induce many of the known defense-related genes but activates a plant's defense signaling upon pathogen exposure.

  7. Potatoes, pathogens and pests

    NARCIS (Netherlands)

    Lazebnik, Jenny

    2017-01-01

    Currently, fungicides are necessary to protect potato crops against late blight, Phytophthora infestans, one of the world’s most damaging crop pathogens. The introgression of plant resistance genes from wild potato species targeted specifically to the late blight pathogen into

  8. Acute Effects of Sugars and Artificial Sweeteners on Small Intestinal Sugar Transport: A Study Using CaCo-2 Cells As an In Vitro Model of the Human Enterocyte.

    Science.gov (United States)

    O'Brien, Patrick; Corpe, Christopher Peter

    2016-01-01

    The gastrointestinal tract is responsible for the assimilation of nutrients and plays a key role in the regulation of nutrient metabolism and energy balance. The molecular mechanisms by which intestinal sugar transport are regulated are controversial. Based on rodent studies, two models currently exist that involve activation of the sweet-taste receptor, T1R2/3: an indirect model, whereby luminal carbohydrates activate T1R2/3 expressed on enteroendocrine cells, resulting in the release of gut peptides which in turn regulate enterocyte sugar transport capacity; and a direct model, whereby T1R2/3 expressed on the enterocyte regulates enterocyte function. To study the direct model of intestinal sugar transport using CaCo-2 cells, a well-established in vitro model of the human enterocyte. Uptake of 10mM 14C D-Glucose and D-Fructose into confluent CaCo-2/TC7 cells was assessed following 3hr preincubation with sugars and artificial sweeteners in the presence and absence of the sweet taste receptor inhibitor, lactisole. Expression of the intestinal sugar transporters and sweet-taste receptors were also determined by RT-PCR. In response to short term changes in extracellular glucose and glucose/fructose concentrations (2.5mM to 75mM) carrier-mediated sugar uptake mediated by SGLT1 and/or the facilitative hexose transporters (GLUT1,2,3 and 5) was increased. Lactisole and artificial sweeteners had no effect on sugar transport regulated by glucose alone; however, lactisole increased glucose transport in cells exposed to glucose/fructose. RT-PCR revealed Tas1r3 and SGLT3 gene expression in CaCo-2/TC7 cells, but not Tas1r2. In the short term, enterocyte sugar transport activities respond directly to extracellular glucose levels, but not fructose or artificial sweeteners. We found no evidence of a functional heterodimeric sweet taste receptor, T1R2/3 in CaCo-2 cells. However, when glucose/fructose is administered together there is an inhibitory effect on glucose transport

  9. Acute Effects of Sugars and Artificial Sweeteners on Small Intestinal Sugar Transport: A Study Using CaCo-2 Cells As an In Vitro Model of the Human Enterocyte.

    Directory of Open Access Journals (Sweden)

    Patrick O'Brien

    Full Text Available The gastrointestinal tract is responsible for the assimilation of nutrients and plays a key role in the regulation of nutrient metabolism and energy balance. The molecular mechanisms by which intestinal sugar transport are regulated are controversial. Based on rodent studies, two models currently exist that involve activation of the sweet-taste receptor, T1R2/3: an indirect model, whereby luminal carbohydrates activate T1R2/3 expressed on enteroendocrine cells, resulting in the release of gut peptides which in turn regulate enterocyte sugar transport capacity; and a direct model, whereby T1R2/3 expressed on the enterocyte regulates enterocyte function.To study the direct model of intestinal sugar transport using CaCo-2 cells, a well-established in vitro model of the human enterocyte.Uptake of 10mM 14C D-Glucose and D-Fructose into confluent CaCo-2/TC7 cells was assessed following 3hr preincubation with sugars and artificial sweeteners in the presence and absence of the sweet taste receptor inhibitor, lactisole. Expression of the intestinal sugar transporters and sweet-taste receptors were also determined by RT-PCR.In response to short term changes in extracellular glucose and glucose/fructose concentrations (2.5mM to 75mM carrier-mediated sugar uptake mediated by SGLT1 and/or the facilitative hexose transporters (GLUT1,2,3 and 5 was increased. Lactisole and artificial sweeteners had no effect on sugar transport regulated by glucose alone; however, lactisole increased glucose transport in cells exposed to glucose/fructose. RT-PCR revealed Tas1r3 and SGLT3 gene expression in CaCo-2/TC7 cells, but not Tas1r2.In the short term, enterocyte sugar transport activities respond directly to extracellular glucose levels, but not fructose or artificial sweeteners. We found no evidence of a functional heterodimeric sweet taste receptor, T1R2/3 in CaCo-2 cells. However, when glucose/fructose is administered together there is an inhibitory effect on glucose

  10. Processes for managing pathogens.

    Science.gov (United States)

    Godfree, Alan; Farrell, Joseph

    2005-01-01

    Wastewater contains human, animal, and plant pathogens capable of causing viral, bacterial, or parasitic infections. There are several routes whereby sewage pathogens may affect human health, including direct contact, contamination of food crops, zoonoses, and vectors. The range and numbers of pathogens in municipal wastewater vary with the level of endemic disease in the community, discharges from commercial activities, and seasonal factors. Regulations to control pathogen risk in the United States and Europe arising from land application of biosolids are based on the concept of multiple barriers to the prevention of transmission. The barriers are (i) treatment to reduce pathogen content and vector attraction, (ii) restrictions on crops grown on land to which biosolids have been applied, and (iii) minimum intervals following application and grazing or harvesting. Wastewater treatment reduces number of pathogens in the wastewater by concentrating them with the solids in the sludge. Although some treatment processes are designed specifically to inactivate pathogens, many are not, and the actual mechanisms of microbial inactivation are not fully understood for all processes. Vector attraction is reduced by stabilization (reduction of readily biodegradable material) and/or incorporation immediately following application. Concerns about health risks have renewed interest in the effects of treatment (on pathogens) and advanced treatment methods, and work performed in the United States suggests that Class A pathogen reduction can be achieved less expensively than previously thought. Effective pathogen risk management requires control to the complete chain of sludge treatment, biosolids handling and application, and post-application activities. This may be achieved by adherence to quality management systems based on hazard analysis critical control point (HACCP) principles.

  11. Correlating levels of type III secretion and secreted proteins with fecal shedding of Escherichia coli O157:H7 in cattle

    Science.gov (United States)

    The locus of enterocyte effacement (LEE) encodes a type III secretion system (T3SS) for secreting factors that enable Escherichia coli O157:H7 to produce attaching and effacing lesions (A/E) on epithelial cells. The importance of LEE-encoded proteins in intestinal colonization of cattle is well-stud...

  12. The symbiotic bacterial surface factor polysaccharide A on Bacteroides fragilis inhibits IL-1β-induced inflammation in human fetal enterocytes via toll receptors 2 and 4.

    Directory of Open Access Journals (Sweden)

    Fei Jiang

    Full Text Available Colonizing bacteria interacting with the immature, unlike the mature, human intestine favors inflammation over immune homeostasis. As a result, ten percent of premature infants under 1500 grams weight develop an inflammatory necrosis of the intestine after birth, e.g., necrotizing enterocolitis (NEC. NEC is a major health problem in this population causing extensive morbidity and mortality and an enormous expenditure of health care dollars. NEC can be prevented by giving preterm infants their mother's expressed breast milk or ingesting selective probiotic organisms. Vaginally delivered, breast fed newborns develop health promoting bacteria ("pioneer" bacteria which preferentially stimulate intestinal host defense and anti-inflammation. One such "pioneer" organism is Bacteroides fragilis with a polysaccharide (PSA on its capsule. B. fragilis has been shown developmentally in intestinal lymphocytes and dendritic cells to produce a balanced T-helper cell (TH1/TH2 response and to reduce intestinal inflammation by activity through the TLR2 receptor stimulating IL-10 which inhibits IL-17 causing inflammation. No studies have been done on the role of B. fragilis PSA on fetal enterocytes and its increased inflammation. Accordingly, using human and mouse fetal intestinal models, we have shown that B. fragilis with PSA and PSA alone inhibits IL-1β-induced IL-8 inflammation in fetal and NEC intestine. We have also begun to define the mechanism for this unique inflammation noted in fetal intestine. We have shown that B. fragilis PSA anti-inflammation requires both the TLR2 and TLR4 receptor and is in part mediated by the AP1 transcription factor (TLR2 which is developmentally regulated. These observations may help to devise future preventative treatments of premature infants against NEC.

  13. Indicators for waterborne pathogens

    National Research Council Canada - National Science Library

    Committee on Indicators for Waterborne Pathogens; Board on Life Sciences; Water Science and Technology Board; Division on Earth and Life Studies; National Research Council; National Academy of Sciences

    2004-01-01

    ... not practical or feasible to monitor for the complete spectrum of microorganisms that may occur in water, and many known pathogens are difficult to detect directly and reliably in water samples.Â...

  14. Evolution of microbial pathogens

    National Research Council Canada - National Science Library

    DiRita, Victor J; Seifert, H. Steven

    2006-01-01

    ... A. Hogan vvi ■ CONTENTS 8. Evolution of Pathogens in Soil Rachel Muir and Man-Wah Tan / 131 9. Experimental Models of Symbiotic Host-Microbial Relationships: Understanding the Underpinnings of ...

  15. Host–Pathogen Interactions

    NARCIS (Netherlands)

    Smits, M.A.; Schokker, D.J.

    2011-01-01

    The outcome of an infection is determined by numerous interactions between hosts and pathogens occurring at many different biological levels, ranging from molecule to population. To develop new control strategies for infectious diseases in livestock species, appropriate methodologies are needed

  16. Candida albicans pathogenicity mechanisms.

    Science.gov (United States)

    Mayer, François L; Wilson, Duncan; Hube, Bernhard

    2013-02-15

    The polymorphic fungus Candida albicans is a member of the normal human microbiome. In most individuals, C. albicans resides as a lifelong, harmless commensal. Under certain circumstances, however, C. albicans can cause infections that range from superficial infections of the skin to life-threatening systemic infections. Several factors and activities have been identified which contribute to the pathogenic potential of this fungus. Among them are molecules which mediate adhesion to and invasion into host cells, the secretion of hydrolases, the yeast-to-hypha transition, contact sensing and thigmotropism, biofilm formation, phenotypic switching and a range of fitness attributes. Our understanding of when and how these mechanisms and factors contribute to infection has significantly increased during the last years. In addition, novel virulence mechanisms have recently been discovered. In this review we present an update on our current understanding of the pathogenicity mechanisms of this important human pathogen.

  17. Candida albicans pathogenicity mechanisms

    Science.gov (United States)

    Mayer, François L.; Wilson, Duncan; Hube, Bernhard

    2013-01-01

    The polymorphic fungus Candida albicans is a member of the normal human microbiome. In most individuals, C. albicans resides as a lifelong, harmless commensal. Under certain circumstances, however, C. albicans can cause infections that range from superficial infections of the skin to life-threatening systemic infections. Several factors and activities have been identified which contribute to the pathogenic potential of this fungus. Among them are molecules which mediate adhesion to and invasion into host cells, the secretion of hydrolases, the yeast-to-hypha transition, contact sensing and thigmotropism, biofilm formation, phenotypic switching and a range of fitness attributes. Our understanding of when and how these mechanisms and factors contribute to infection has significantly increased during the last years. In addition, novel virulence mechanisms have recently been discovered. In this review we present an update on our current understanding of the pathogenicity mechanisms of this important human pathogen. PMID:23302789

  18. Protective Effects of Bifidobacterium on Intestinal Barrier Function in LPS-Induced Enterocyte Barrier Injury of Caco-2 Monolayers and in a Rat NEC Model.

    Directory of Open Access Journals (Sweden)

    Xiang Ling

    Full Text Available Zonulin protein is a newly discovered modulator which modulates the permeability of the intestinal epithelial barrier by disassembling intercellular tight junctions (TJ. Disruption of TJ is associated with neonatal necrotizing enterocolitis (NEC. It has been shown bifidobacterium could protect the intestinal barrier function and prophylactical administration of bifidobacterium has beneficial effects in NEC patients and animals. However, it is still unknown whether the zonulin is involved in the gut barrier dysfunction of NEC, and the protective mechanisms of bifidobacterium on intestinal barrier function are also not well understood. The present study aims to investigate the effects of bifidobacterium on intestinal barrier function, zonulin regulation, and TJ integrity both in LPS-induced enterocyte barrier injury of Caco-2 monolayers and in a rat NEC model. Our results showed bifidobacterium markedly attenuated the decrease in transepithelial electrical resistance and the increase in paracellular permeability in the Caco-2 monolayers treated with LPS (P < 0.01. Compared with the LPS group, bifidobacterium significantly decreased the production of IL-6 and TNF-α (P < 0.01 and suppressed zonulin release (P < 0.05. In addition, bifidobacterium pretreatment up-regulated occludin, claudin-3 and ZO-1 expression (P < 0.01 and also preserved these proteins localization at TJ compared with the LPS group. In the in vivo study, bifidobacterium decreased the incidence of NEC from 88 to 47% (P < 0.05 and reduced the severity in the NEC model. Increased levels of IL-6 and TNF-α in the ileum of NEC rats were normalized in bifidobacterium treated rats (P < 0.05. Moreover, administration of bifidobacterium attenuated the increase in intestinal permeability (P < 0.01, decreased the levels of serum zonulin (P < 0.05, normalized the expression and localization of TJ proteins in the ileum compared with animals with NEC. We concluded that bifidobacterium may

  19. Human pathogen avoidance adaptations

    NARCIS (Netherlands)

    Tybur, J.M.; Lieberman, D.

    2016-01-01

    Over the past few decades, researchers have become increasingly interested in the adaptations guiding the avoidance of disease-causing organisms. Here we discuss the latest developments in this area, including a recently developed information-processing model of the adaptations underlying pathogen

  20. Pathogenicity and virulence

    Science.gov (United States)

    Many pathogenic microorganisms are host-specific in that they parasitize only one or a few animal species. For example, the cause of equine strangles, Streptococcus equi subspecies equi, is essentially limited to infection of horses. Others—certain Salmonella serotypes, for example—have a broad host...

  1. The pathogenic E. coli type III effector EspZ interacts with host CD98 and facilitates host cell prosurvival signalling.

    Science.gov (United States)

    Shames, Stephanie R; Deng, Wanyin; Guttman, Julian A; de Hoog, Carmen L; Li, Yuling; Hardwidge, Philip R; Sham, Ho Pan; Vallance, Bruce A; Foster, Leonard J; Finlay, B Brett

    2010-09-01

    Enterohaemorrhagic and enteropathogenic Escherichia coli (EHEC and EPEC respectively) are diarrhoeal pathogens that cause the formation of attaching and effacing (A/E) lesions on infected host cells. These pathogens encode a type III secretion system (T3SS) used to inject effector proteins directly into host cells, an essential requirement for virulence. In this study, we identified a function for the type III secreted effector EspZ. Infection with EPEC DeltaespZ caused increased cytotoxicity in HeLa and MDCK cells compared with wild-type EPEC, and expressing espZ in cells abrogated this effect. Using yeast two-hybrid, proteomics, immunofluorescence and co-immunoprecipitation, it was demonstrated that EspZ interacts with the host protein CD98, which contributes to protection against EPEC-mediated cytotoxicity. EspZ enhanced phosphorylation of focal adhesion kinase (FAK) and AKT during infection with EPEC, but CD98 only appeared to facilitate FAK phosphorylation. This study provides evidence that EspZ and CD98 promote host cell survival mechanisms involving FAK during A/E pathogen infection.

  2. Autophagy in plant pathogenic fungi.

    Science.gov (United States)

    Liu, Xiao-Hong; Xu, Fei; Snyder, John Hugh; Shi, Huan-Bin; Lu, Jian-Ping; Lin, Fu-Cheng

    2016-09-01

    Autophagy is a conserved cellular process that degrades cytoplasmic constituents in vacuoles. Plant pathogenic fungi develop special infection structures and/or secrete a range of enzymes to invade their plant hosts. It has been demonstrated that monitoring autophagy processes can be extremely useful in visualizing the sequence of events leading to pathogenicity of plant pathogenic fungi. In this review, we introduce the molecular mechanisms involved in autophagy. In addition, we explore the relationship between autophagy and pathogenicity in plant pathogenic fungi. Finally, we discuss the various experimental strategies available for use in the study of autophagy in plant pathogenic fungi. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Filamentous pathogen effector functions: of pathogens, hosts and microbiomes

    NARCIS (Netherlands)

    Rövenich, H.; Boshoven, J.C.; Thomma, B.

    2014-01-01

    Microorganisms play essential roles in almost every environment on earth. For instance, microbes decompose organic material, or establish symbiotic relationships that range from pathogenic to mutualistic. Symbiotic relationships have been particularly well studied for microbial plant pathogens and

  4. Candida albicans pathogenicity mechanisms

    OpenAIRE

    Mayer, Fran?ois L.; Wilson, Duncan; Hube, Bernhard

    2013-01-01

    The polymorphic fungus Candida albicans is a member of the normal human microbiome. In most individuals, C. albicans resides as a lifelong, harmless commensal. Under certain circumstances, however, C. albicans can cause infections that range from superficial infections of the skin to life-threatening systemic infections. Several factors and activities have been identified which contribute to the pathogenic potential of this fungus. Among them are molecules which mediate adhesion to and invasi...

  5. Multiplex detection of agricultural pathogens

    Science.gov (United States)

    Siezak, Thomas R.; Gardner, Shea; Torres, Clinton; Vitalis, Elizabeth; Lenhoff, Raymond J.

    2013-01-15

    Described are kits and methods useful for detection of agricultural pathogens in a sample. Genomic sequence information from agricultural pathogens was analyzed to identify signature sequences, e.g., polynucleotide sequences useful for confirming the presence or absence of a pathogen in a sample. Primer and probe sets were designed and optimized for use in a PCR based, multiplexed Luminex assay and/or an array assay to successfully identify the presence or absence of pathogens in a sample.

  6. Cryptosporidium Pathogenicity and Virulence

    Science.gov (United States)

    Bouzid, Maha; Chalmers, Rachel M.; Tyler, Kevin M.

    2013-01-01

    Cryptosporidium is a protozoan parasite of medical and veterinary importance that causes gastroenteritis in a variety of vertebrate hosts. Several studies have reported different degrees of pathogenicity and virulence among Cryptosporidium species and isolates of the same species as well as evidence of variation in host susceptibility to infection. The identification and validation of Cryptosporidium virulence factors have been hindered by the renowned difficulties pertaining to the in vitro culture and genetic manipulation of this parasite. Nevertheless, substantial progress has been made in identifying putative virulence factors for Cryptosporidium. This progress has been accelerated since the publication of the Cryptosporidium parvum and C. hominis genomes, with the characterization of over 25 putative virulence factors identified by using a variety of immunological and molecular techniques and which are proposed to be involved in aspects of host-pathogen interactions from adhesion and locomotion to invasion and proliferation. Progress has also been made in the contribution of host factors that are associated with variations in both the severity and risk of infection. Here we provide a review comprised of the current state of knowledge on Cryptosporidium infectivity, pathogenesis, and transmissibility in light of our contemporary understanding of microbial virulence. PMID:23297262

  7. Pathogenic mycoflora on carrot seeds

    Directory of Open Access Journals (Sweden)

    Bogdan Nowicki

    2013-12-01

    Full Text Available Altogether 300 seed samples were collected during 9 years in 8 regions of Poland and the fungi Were isolated and their pathogenicity to carrot seedlings was examined. Alternaria rudicina provcd to be the most important pathogen although. A. alternata was more common. The other important pathogens were Fusarium spp., Phoma spp. and Botrytis cinerea. The infection of carrot seeds by A. radicina should be used as an important criterium in seed quality evaluation.

  8. The pathogenic equine streptococci.

    Science.gov (United States)

    Timoney, John F

    2004-01-01

    Streptococci pathogenic for the horse include S. equi (S. equi subsp. equi), S. zooepidemicus (S. equi subsp. zooepidemicus), S. dysgalactiae subsp. equisimilis and S. pneumoniae capsule Type III. S. equi is a clonal descendent or biovar of an ancestral S. zooepidemicus strain with which it shares greater than 98% DNA homology and therefore expresses many of the same proteins and virulence factors. Rapid progress has been made in identification of virulence factors and proteins uniquely expressed by S. equi. Most of these are expressed either on the bacterial surface or are secreted. Notable examples include the antiphagocytic SeM and the secreted pyrogenic superantigens SePE-I and H. The genomic DNA sequence of S. equi will greatly accelerate identification and characterization of additional virulence factors and vaccine targets. Although it is the most frequently isolated opportunist pyogen of the horse, S. zooepidemicus has been the subject of few contemporary research studies. Variation in the protectively immunogenic SzP proteins has, however, been well characterized. Given its opportunist behavior, studies are urgently needed on regulation of virulence factors such as capsule and proteases. Likewise, information is also very limited on virulence factors and associated gene regulation of S. dysgalactiae subspecies equisimilis. It has recently been shown that equine isolates of Streptococcus pneumoniae are clonal, a feature shared with S. equi. All equine isolates express capsule Type III, are genetically similar, and have deletions in the genes for autolysin and pneumolysin. In summary, the evolving picture of the interaction of the equine pathogenic streptococci and their host is that of multiple virulence factors active at different stages of pathogenesis. The inherent complexity of this interaction suggests that discovery of effective combinations of immunogens from potential targets identified in genomic sequence will be laborious.

  9. Multiplex detection of respiratory pathogens

    Science.gov (United States)

    McBride, Mary [Brentwood, CA; Slezak, Thomas [Livermore, CA; Birch, James M [Albany, CA

    2012-07-31

    Described are kits and methods useful for detection of respiratory pathogens (influenza A (including subtyping capability for H1, H3, H5 and H7 subtypes) influenza B, parainfluenza (type 2), respiratory syncytial virus, and adenovirus) in a sample. Genomic sequence information from the respiratory pathogens was analyzed to identify signature sequences, e.g., polynucleotide sequences useful for confirming the presence or absence of a pathogen in a sample. Primer and probe sets were designed and optimized for use in a PCR based, multiplexed Luminex assay to successfully identify the presence or absence of pathogens in a sample.

  10. Comparative proteomic analysis of pathogenic and non-pathogenic strains from the swine pathogen Mycoplasma hyopneumoniae

    Directory of Open Access Journals (Sweden)

    Klein Cátia S

    2009-12-01

    Full Text Available Abstract Background Mycoplasma hyopneumoniae is a highly infectious swine pathogen and is the causative agent of enzootic pneumonia (EP. Following the previous report of a proteomic survey of the pathogenic 7448 strain of swine pathogen, Mycoplasma hyopneumoniae, we performed comparative protein profiling of three M. hyopneumoniae strains, namely the non-pathogenic J strain and the two pathogenic strains 7448 and 7422. Results In 2DE comparisons, we were able to identify differences in expression levels for 67 proteins, including the overexpression of some cytoadherence-related proteins only in the pathogenic strains. 2DE immunoblot analyses allowed the identification of differential proteolytic cleavage patterns of the P97 adhesin in the three strains. For more comprehensive protein profiling, an LC-MS/MS strategy was used. Overall, 35% of the M. hyopneumoniae genome coding capacity was covered. Partially overlapping profiles of identified proteins were observed in the strains with 81 proteins identified only in one strain and 54 proteins identified in two strains. Abundance analysis of proteins detected in more than one strain demonstrates the relative overexpression of 64 proteins, including the P97 adhesin in the pathogenic strains. Conclusions Our results indicate the physiological differences between the non-pathogenic strain, with its non-infective proliferate lifestyle, and the pathogenic strains, with its constitutive expression of adhesins, which would render the bacterium competent for adhesion and infection prior to host contact.

  11. The Tip of the Iceberg: On the Roles of Regulatory Small RNAs in the virulence of Enterohemorrhagic and Enteropathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Shantanu Bhatt

    2016-09-01

    Full Text Available Enterohemorrhagic and enteropathogenic Escherichia coli are gastrointestinal pathogens that disrupt the intestinal microvilli to form attaching and effacing (A/E lesions on infected cells and cause diarrhea. This pathomorphological trait is encoded within the pathogenicity island locus of enterocyte effacement (LEE. The LEE houses a type 3 secretion system (T3SS, which upon assembly bridges the bacterial cytosol to that of the host and enables the bacterium to traffic dozens of effectors into the host where they hijack regulatory and signal transduction pathways and contribute to bacterial colonization and disease. Owing to the importance of the LEE to EHEC and EPEC pathogenesis, much of the research on these pathogens has centered on its regulation. To date, over forty proteinaceous factors have been identified that control the LEE at various hierarchical levels of gene expression. In contrast, RNA-based regulatory mechanisms that converge on the LEE have only just begun to be unraveled. In this minireview, we highlight major breakthroughs in small RNAs (sRNAs-dependent regulation of the LEE, with an emphasis on their mechanisms of action and/or LEE-encoded targets.

  12. The Tip of the Iceberg: On the Roles of Regulatory Small RNAs in the Virulence of Enterohemorrhagic and EnteropathogenicEscherichia coli.

    Science.gov (United States)

    Bhatt, Shantanu; Egan, Marisa; Jenkins, Valerie; Muche, Sarah; El-Fenej, Jihad

    2016-01-01

    Enterohemorrhagic and enteropathogenic Escherichia coli are gastrointestinal pathogens that disrupt the intestinal microvilli to form attaching and effacing (A/E) lesions on infected cells and cause diarrhea. This pathomorphological trait is encoded within the pathogenicity island locus of enterocyte effacement (LEE). The LEE houses a type 3 secretion system (T3SS), which upon assembly bridges the bacterial cytosol to that of the host and enables the bacterium to traffic dozens of effectors into the host where they hijack regulatory and signal transduction pathways and contribute to bacterial colonization and disease. Owing to the importance of the LEE to EHEC and EPEC pathogenesis, much of the research on these pathogens has centered on its regulation. To date, over 40 proteinaceous factors have been identified that control the LEE at various hierarchical levels of gene expression. In contrast, RNA-based regulatory mechanisms that converge on the LEE have only just begun to be unraveled. In this minireview, we highlight major breakthroughs in small RNAs (sRNAs)-dependent regulation of the LEE, with an emphasis on their mechanisms of action and/or LEE-encoded targets.

  13. Ecology of Pathogen Groups: Fungi

    DEFF Research Database (Denmark)

    Hajek, Ann E.; Meyling, Nicolai Vitt

    2018-01-01

    Summary This chapter investigates the recent results of studies of the ecology of fungal pathogens, including ecological insights obtained by implementation of molecular tools. It spans a spectrum of invertebrates as hosts, although emphasis will be on pathogens of terrestrial insects, which have...... been the focus of most ecological research. Some taxa of invertebrate pathogenic fungi have evolved adaptations for utilizing living plants as substrates, and these lifestyles have recently received increased attention from researchers following the initial documentations of such plant associations...... by Beauveria and Metarhizium. This topic has recently been reviewed; the chapter mainly focuses on aspects of ecological relevance, including trophic interactions. Fungal pathogens are used to provide biological control in numerous ways. The primary type of biological control emphasized for fungal pathogens...

  14. The pathogenicity of cytomegalovirus.

    Science.gov (United States)

    Sweet, C

    1999-07-01

    Human cytomegalovirus is ubiquitous, yet causes little illness in immunocompetent individuals. Disease is evident in immunodeficient groups such as neonates, transplant recipients and AIDS patients either following a primary infection or reactivation of a latent infection. Little is known of the mechanisms underlying the pathogenicity of the virus. The recent determination of the nucleotide sequence of both human cytomegalovirus (strain AD169) and murine cytomegalovirus (murine cytomegalovirus strain Smith) has allowed an analysis of the biological importance of several virus genes. Studies with human cytomegalovirus have indicated that many viral genes are non-essential for replication in vitro which are thus assumed to be important in the pathogenesis of the virus. This is being examined in the murine model where the role of the gene and its product in disease can be directly examined in vivo using viral mutants in which the relevant gene has been interrupted or deleted. Current information on the role of cytomegalovirus genes in tissue tropism, immune evasion, latency, reactivation from latency and damage is described.

  15. Genomics of clostridial pathogens: implication of extrachromosomal elements in pathogenicity.

    Science.gov (United States)

    Brüggemann, Holger

    2005-10-01

    The recently decoded genomes of the major clostridial toxin-producing pathogens Clostridium perfringens, Clostridium tetani, Clostridium botulinum and Clostridium difficile have provided a huge amount of new sequence data. Recent studies have focused on the identification and investigation of pathogenic determinants and the regulatory events governing their expression. The sequence data revealed also the genomic background of virulence genes, as well as the contribution of extrachromosomal elements to a pathogenic phenotype. This has generated new insights in clostridial pathogenesis - and will continue to do so in the future - and has deepened our understanding of the anaerobic lifestyle of clostridial species.

  16. Opportunistic Premise Plumbing Pathogens: Increasingly Important Pathogens in Drinking Water

    Directory of Open Access Journals (Sweden)

    Joseph O. Falkinham

    2015-06-01

    Full Text Available Opportunistic premise plumbing pathogens are responsible for a significant number of infections whose origin has been traced to drinking water. These opportunistic pathogens represent an emerging water borne disease problem with a major economic cost of at least $1 billion annually. The common features of this group of waterborne pathogens include: disinfectant-resistance, pipe surface adherence and biofilm formation, growth in amoebae, growth on low organic concentrations, and growth at low oxygen levels. Their emergence is due to the fact that conditions resulting from drinking water treatment select for them. As such, there is a need for novel approaches to reduce exposure to these pathogens. In addition to much-needed research, controls to reduce numbers and human exposure can be instituted independently by utilities and homeowners and hospital- and building-operators.

  17. Opportunistic Premise Plumbing Pathogens: Increasingly Important Pathogens in Drinking Water.

    Science.gov (United States)

    Falkinham, Joseph O; Pruden, Amy; Edwards, Marc

    2015-06-09

    Opportunistic premise plumbing pathogens are responsible for a significant number of infections whose origin has been traced to drinking water. These opportunistic pathogens represent an emerging water borne disease problem with a major economic cost of at least $1 billion annually. The common features of this group of waterborne pathogens include: disinfectant-resistance, pipe surface adherence and biofilm formation, growth in amoebae, growth on low organic concentrations, and growth at low oxygen levels. Their emergence is due to the fact that conditions resulting from drinking water treatment select for them. As such, there is a need for novel approaches to reduce exposure to these pathogens. In addition to much-needed research, controls to reduce numbers and human exposure can be instituted independently by utilities and homeowners and hospital- and building-operators.

  18. Ecological niche of plant pathogens

    Directory of Open Access Journals (Sweden)

    Ecaterina Fodor

    2011-02-01

    Full Text Available Disease ecology is a new approach to the understanding of the spread and dynamics of pathogens in natural and man-made environments. Defining and describing the ecological niche of the pathogens is one of the major tasks for ecological theory, as well as for practitioners preoccupied with the control and forecasting of established and emerging diseases. Niche theory has been periodically revised, not including in an explicit way the pathogens. However, many progresses have been achieved in niche modeling of disease spread, but few attempts were made to construct a theoretical frame for the ecological niche of pathogens. The paper is a review of the knowledge accumulated during last decades in the niche theory of pathogens and proposes an ecological approach in research. It quest for new control methods in what concerns forest plant pathogens, with a special emphasis on fungi like organisms of the genus Phytophthora. Species of Phytophthora are the most successful plant pathogens of the moment, affecting forest and agricultural systems worldwide, many of them being invasive alien organisms in many ecosystems. The hyperspace of their ecological niche is defined by hosts, environment and human interference, as main axes. To select most important variables within the hyperspace, is important for the understanding of the complex role of pathogens in the ecosystems as well as for control programs. Biotic relationships within ecosystem of host-pathogen couple are depicted by ecological network and specific metrics attached to this. The star shaped network is characterized by few high degree nodes, by short path lengths and relatively low connectivity, premises for a rapid disturbance spread.

  19. Ecological niche of plant pathogens

    Directory of Open Access Journals (Sweden)

    Ecaterina Fodor

    2011-06-01

    Full Text Available Disease ecology is a new approach to the understanding of the spread and dynamics of pathogens in natural and man-made environments. Defining and describing the ecological niche of the pathogens is one of the major tasks for ecological theory, as well as for practitioners preoccupied with the control and forecasting of established and emerging diseases. Niche theory has been periodically revised, not including in an explicit way the pathogens. However, many progresses have been achieved in niche modeling of disease spread, but few attempts were made to construct a theoretical frame for the ecological niche of pathogens. The paper is a review of the knowledge accumulated during last decades in the niche theory of pathogens and proposes an ecological approach in research. It quest for new control methods in what concerns forest plant pathogens, with a special emphasis on fungi like organisms of the genus Phytophthora. Species of Phytophthora are the most successful plant pathogens of the moment, affecting forest and agricultural systems worldwide, many of them being invasive alien organisms in many ecosystems. The hyperspace of their ecological niche is defined by hosts, environment and human interference, as main axes. To select most important variables within the hyperspace, is important the understanding of the complex role of pathogens in the ecosystems as well as for control programs. Biotic relationships within ecosystem of host-pathogen couple are depicted by ecological network and specific metrics attached to this. The star shaped network is characterized by few high degree nodes, by short path lengths and relatively low connectivity, premises for a rapid disturbance spread. 

  20. How plants recognize pathogens and defend themselves

    NARCIS (Netherlands)

    Wit, de P.J.G.M.

    2007-01-01

    Plants have an innate immunity system to defend themselves against pathogens. With the primary immune system, plants recognize microbe-associated molecular patterns (MAMPs) of potential pathogens through pattern recognition receptors (PRRs) that mediate a basal defense response. Plant pathogens

  1. Molecular Soybean-Pathogen Interactions.

    Science.gov (United States)

    Whitham, Steven A; Qi, Mingsheng; Innes, Roger W; Ma, Wenbo; Lopes-Caitar, Valéria; Hewezi, Tarek

    2016-08-04

    Soybean hosts a wide variety of pathogens that cause significant yield losses. The importance of soybean as a major oilseed crop has led to research focused on its interactions with pathogens, such as Soybean mosaic virus, Pseudomonas syringae, Phytophthora sojae, Phakopsora pachyrhizi, and Heterodera glycines. Pioneering work on soybean's interactions with these organisms, which represent the five major pathogen groups (viruses, bacteria, oomycetes, fungi, and nematodes), has contributed to our understanding of the molecular mechanisms underlying virulence and immunity. These mechanisms involve conserved and unique features that validate the need for research in both soybean and homologous model systems. In this review, we discuss identification of effectors and their functions as well as resistance gene-mediated recognition and signaling. We also point out areas in which model systems and recent advances in resources and tools have provided opportunities to gain deeper insights into soybean-pathogen interactions.

  2. Antibiotic Resistance in Foodborne Pathogens

    OpenAIRE

    Walsh, Ciara; Duffy, Geraldine

    2013-01-01

    Wide-spread antibiotic resistance among bacterial pathogens is now a serious public health issue and multi-antibiotic resistance has been reported in many foodborne pathogens including Salmonella and E. coli. A study to determine antibiotic resistance profiles of a range of Salmonella and Verocytotoxigenic E.coli (VTEC) isolated from Irish foods revealed significant levels of antibiotic resistance in the strains. S. typhimurium DT104 were multiantibiotic resistant with 97% resistant to 7 anti...

  3. Molecular detection of human bacterial pathogens

    National Research Council Canada - National Science Library

    Liu, Dongyou

    2011-01-01

    .... Molecular Detection of Human Bacterial Pathogens addresses this issue, with international scientists in respective bacterial pathogen research and diagnosis providing expert summaries on current...

  4. Enterohemorrhagic Escherichia coli senses low biotin status in the large intestine for colonization and infection.

    Science.gov (United States)

    Yang, Bin; Feng, Lu; Wang, Fang; Wang, Lei

    2015-03-20

    Enterohemorrhagic Escherichia coli (EHEC) is an important foodborne pathogen that infects humans by colonizing the large intestine. Here we identify a virulence-regulating pathway in which the biotin protein ligase BirA signals to the global regulator Fur, which in turn activates LEE (locus of enterocyte effacement) genes to promote EHEC adherence in the low-biotin large intestine. LEE genes are repressed in the high-biotin small intestine, thus preventing adherence and ensuring selective colonization of the large intestine. The presence of this pathway in all nine EHEC serotypes tested indicates that it is an important evolutionary strategy for EHEC. The pathway is incomplete in closely related small-intestinal enteropathogenic E. coli due to the lack of the Fur response to BirA. Mice fed with a biotin-rich diet show significantly reduced EHEC adherence, indicating that biotin might be useful to prevent EHEC infection in humans.

  5. Enterohemorrhagic Escherichia coli senses low biotin status in the large intestine for colonization and infection

    Science.gov (United States)

    Yang, Bin; Feng, Lu; Wang, Fang; Wang, Lei

    2015-01-01

    Enterohemorrhagic Escherichia coli (EHEC) is an important foodborne pathogen that infects humans by colonizing the large intestine. Here we identify a virulence-regulating pathway in which the biotin protein ligase BirA signals to the global regulator Fur, which in turn activates LEE (locus of enterocyte effacement) genes to promote EHEC adherence in the low-biotin large intestine. LEE genes are repressed in the high-biotin small intestine, thus preventing adherence and ensuring selective colonization of the large intestine. The presence of this pathway in all nine EHEC serotypes tested indicates that it is an important evolutionary strategy for EHEC. The pathway is incomplete in closely related small-intestinal enteropathogenic E. coli due to the lack of the Fur response to BirA. Mice fed with a biotin-rich diet show significantly reduced EHEC adherence, indicating that biotin might be useful to prevent EHEC infection in humans. PMID:25791315

  6. The Type Three Secretion System 2-Encoded Regulator EtrB Modulates Enterohemorrhagic Escherichia coli Virulence Gene Expression.

    Science.gov (United States)

    Luzader, Deborah H; Willsey, Graham G; Wargo, Matthew J; Kendall, Melissa M

    2016-09-01

    Enterohemorrhagic Escherichia coli O157:H7 (EHEC) is a foodborne pathogen that causes bloody diarrhea and hemolytic uremic syndrome throughout the world. A defining feature of EHEC pathogenesis is the formation of attaching and effacing (AE) lesions on colonic epithelial cells. Most of the genes that code for AE lesion formation, including a type three secretion system (T3SS) and effectors, are carried within a chromosomal pathogenicity island called the locus of enterocyte effacement (LEE). In this study, we report that a putative regulator, which is encoded in the cryptic E. coli type three secretion system 2 (ETT2) locus and herein renamed EtrB, plays an important role in EHEC pathogenesis. The etrB gene is expressed as a monocistronic transcript, and EtrB autoregulates expression. We provide evidence that EtrB directly interacts with the ler regulatory region to activate LEE expression and promote AE lesion formation. Additionally, we mapped the EtrB regulatory circuit in EHEC to determine a global role for EtrB. EtrB is regulated by the transcription factor QseA, suggesting that these proteins comprise a regulatory circuit important for EHEC colonization of the gastrointestinal tract. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  7. EscA is a crucial component of the type III secretion system of enteropathogenic Escherichia coli.

    Science.gov (United States)

    Sal-Man, Neta; Biemans-Oldehinkel, Esther; Sharon, David; Croxen, Matthew A; Scholz, Roland; Foster, Leonard J; Finlay, B Brett

    2012-06-01

    The virulence of many Gram-negative pathogens is associated with type III secretion systems (T3SSs), which deliver virulence effector proteins into the cytoplasm of host cells. Components of enteropathogenic Escherichia coli (EPEC) T3SS are encoded within the locus of enterocyte effacement (LEE). While most LEE-encoded T3SS proteins in EPEC have assigned names and functions, a few of them remain poorly characterized. Here, we studied a small LEE-encoded protein, Orf15, that shows no homology to other T3SS/flagellar proteins and is only present in attaching and effacing pathogens, including enterohemorrhagic E. coli and Citrobacter rodentium. Our findings demonstrated that it is essential for type III secretion (T3S) and that it is localized to the periplasm and associated with the inner membrane. Membrane association was driven by the N-terminal 19 amino acid residues, which were also shown to be essential for T3S. Consistent with its localization, Orf15 was found to interact with the EPEC T3SS outer membrane ring component, EscC, which was previously shown to be embedded within the outer membrane and protruding into the periplasmic space. Interestingly, we found that the predicted coiled-coil structure of Orf15 is critical for the protein's function. Overall, our findings suggest that Orf15 is a structural protein that contributes to the structural integrity of the T3S complex, and therefore we propose to rename it EscA.

  8. Enteropathogenic escherichia coli infection in children.

    Science.gov (United States)

    Ochoa, Theresa J; Contreras, Carmen A

    2011-10-01

    Enteropathogenic Escherichia coli (EPEC) is an important diarrheal pathogen of young children. As the diagnosis of EPEC is now based mainly on molecular criteria, there has been an important change in its prevalence. The purpose of this study is to review the current epidemiology of EPEC infection and the new insights into its physiopathology. Recent epidemiological studies indicate that atypical EPEC (aEPEC) is more prevalent than typical EPEC (tEPEC) in both developed and developing countries, and that aEPEC is important in both pediatric endemic diarrhea and diarrhea outbreaks. Therefore, it is important to further characterize the pathogenicity of these emerging strains. The virulence mechanisms and physiopathology of the attaching and effacing lesion (A/E) and the type three secretion-system (T3SS) are complex but well studied. A/E strains use their pool of locus of enterocyte effacement (LEE)-encoded and non-LEE-encoded effector proteins to subvert and modulate cellular and barrier properties of the host. However, the exact mechanisms of diarrhea in EPEC infection are not completely understood. Remarkable progress has been made to identify virulence determinants required to mediate the pathogenesis of EPEC. However, fast, easy, and inexpensive diagnostic methods are needed in order to define optimal treatment and prevention for children in endemic areas.

  9. Biosensors for plant pathogen detection.

    Science.gov (United States)

    Khater, Mohga; de la Escosura-Muñiz, Alfredo; Merkoçi, Arben

    2017-07-15

    Infectious plant diseases are caused by pathogenic microorganisms such as fungi, bacteria, viruses, viroids, phytoplasma and nematodes. Worldwide, plant pathogen infections are among main factors limiting crop productivity and increasing economic losses. Plant pathogen detection is important as first step to manage a plant disease in greenhouses, field conditions and at the country boarders. Current immunological techniques used to detect pathogens in plant include enzyme-linked immunosorbent assays (ELISA) and direct tissue blot immunoassays (DTBIA). DNA-based techniques such as polymerase chain reaction (PCR), real time PCR (RT-PCR) and dot blot hybridization have also been proposed for pathogen identification and detection. However these methodologies are time-consuming and require complex instruments, being not suitable for in-situ analysis. Consequently, there is strong interest for developing new biosensing systems for early detection of plant diseases with high sensitivity and specificity at the point-of-care. In this context, we revise here the recent advancement in the development of advantageous biosensing systems for plant pathogen detection based on both antibody and DNA receptors. The use of different nanomaterials such as nanochannels and metallic nanoparticles for the development of innovative and sensitive biosensing systems for the detection of pathogens (i.e. bacteria and viruses) at the point-of-care is also shown. Plastic and paper-based platforms have been used for this purpose, offering cheap and easy-to-use really integrated sensing systems for rapid on-site detection. Beside devices developed at research and development level a brief revision of commercially available kits is also included in this review. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Compositions and methods for pathogen transport

    Energy Technology Data Exchange (ETDEWEB)

    El-Etr, Sahar; Farquar, George R.

    2016-01-26

    This disclosure provides a method for transporting a pathogen under ambient conditions, by culturing the pathogen with an amoeba under conditions that favor the incorporation of the pathogen into a trophozoite, starving the amoeba until it encysts, then culturing under conditions that favor conversion of the amoeba back to a trophozoite. In one aspect, the conditions that favor incorporation of the pathogen into the cyst of the amoeba comprises contacting the pathogen with the amoeba in an iron rich environment. Virus and/or bacteria are pathogens that can be transported by the disclosed method. Amoeba that are useful in the disclosed methods include, without limitation Acanthamoeba castellanii, Hartmannella vermiformis and Naegleria gruberi. The disclosed methods have utility in: transporting pathogens from military field hospitals and clinics to the laboratory; transporting pathogens from global satellite laboratories to clinical laboratories; long term storage of pathogens; enriching contaminated patient samples for pathogens of interest; biosurveillance and detection efforts.

  11. Pathogenicity of highly pathogenic avian influenza virus in mammals

    NARCIS (Netherlands)

    de Wit, Emmie; Kawaoka, Yoshihiro; de Jong, Menno D.; Fouchier, Ron A. M.

    2008-01-01

    In recent years, there has been an increase in outbreaks of highly pathogenic avian influenza (HPAI) in poultry. Occasionally, these outbreaks have resulted in transmission of influenza viruses to humans and other mammals, with symptoms ranging from conjunctivitis to pneumonia and death. Here, the

  12. From multiple pathogenicity islands to a unique organized pathogenicity archipelago.

    Science.gov (United States)

    Bouyioukos, Costas; Reverchon, Sylvie; Képès, François

    2016-06-15

    Pathogenicity islands are sets of successive genes in a genome that determine the virulence of a bacterium. In a growing number of studies, bacterial virulence appears to be determined by multiple islands scattered along the genome. This is the case in a family of seven plant pathogens and a human pathogen that, under KdgR regulation, massively secrete enzymes such as pectinases that degrade plant cell wall. Here we show that their multiple pathogenicity islands form together a coherently organized, single "archipelago" at the genome scale. Furthermore, in half of the species, most genes encoding secreted pectinases are expressed from the same DNA strand (transcriptional co-orientation). This genome architecture favors DNA conformations that are conducive to genes spatial co-localization, sometimes complemented by co-orientation. As proteins tend to be synthetized close to their encoding genes in bacteria, we propose that this architecture would favor the efficient funneling of pectinases at convergent points within the cell. The underlying functional hypothesis is that this convergent funneling of the full blend of pectinases constitutes a crucial strategy for successful degradation of the plant cell wall. Altogether, our work provides a new approach to describe and predict, at the genome scale, the full virulence complement.

  13. New trends in emerging pathogens.

    Science.gov (United States)

    Skovgaard, Niels

    2007-12-15

    The emergence of pathogens is the result of a number of impact in all parts of the food chain. The emerging technologies in food production explain how new pathogens can establish themselves in the food chain and compromise food safety. The impact of the food technology is analysed for several bacteria, such as Yersinia, Campylobacter, Arcobacter, Helicobacter pullorum, Enterobacter sakazakii, Mycobacterium avium spp. paratuberculosis, prions related to vCJD and others. The importance of the ability of many microbes to form VBNC forms is elaborated on. Research on culture independent methods may address this outstanding issue to the better understanding of emerging pathogens. The "demerging" of pathogens also occur, and examples of this are explained. The reaction of bacteria to stresses and sublethal treatments, and how exposure to one stress factor can confer resistance to other stresses, literally speaking causing contagious resistance, are explained. The implication of this e.g. in modern approaches of food preservation, such as Minimally processed Foods, is considerable. Intestinal colonization of EHEC may be regulated by Quorum sensing, and this ability of microbes plays an important role in the colonization of microbes in food and on food processing equipment, an important factor in the emergence of pathogens. The emergence of Saccharomyces cerevisiae, as an opportunistic human pathogen, used for centuries for food and production of alcoholic beverages, calls for research in molecular tools to distinguish between probiotic and clinical strains. Cyclospora cayetanensis and Norovirus outbreaks can no longer be designated as emerging pathogens, they share however one characteristic in the epidemiology of emerging nature, the importance of the hygiene in the primary production stage, including supply of potable water, and the application of GMP and the HACCP principles in the beginning of the food chain. Hepatitis E virus is a potential emerging food borne

  14. Applied Genomics of Foodborne Pathogens

    DEFF Research Database (Denmark)

    This book provides a timely and thorough snapshot into the emerging and fast evolving area of applied genomics of foodborne pathogens. Driven by the drastic advance of whole genome shot gun sequencing (WGS) technologies, genomics applications are becoming increasingly valuable and even essential...... in studying, surveying and controlling foodborne microbial pathogens. The vast opportunities brought by this trend are often at odds with the lack of bioinformatics know-how among food safety and public health professionals, since such expertise is not part of a typical food microbiology curriculum and skill...

  15. Complete genome sequence and comparative genome analysis of enteropathogenic Escherichia coli O127:H6 strain E2348/69.

    Science.gov (United States)

    Iguchi, Atsushi; Thomson, Nicholas R; Ogura, Yoshitoshi; Saunders, David; Ooka, Tadasuke; Henderson, Ian R; Harris, David; Asadulghani, M; Kurokawa, Ken; Dean, Paul; Kenny, Brendan; Quail, Michael A; Thurston, Scott; Dougan, Gordon; Hayashi, Tetsuya; Parkhill, Julian; Frankel, Gad

    2009-01-01

    Enteropathogenic Escherichia coli (EPEC) was the first pathovar of E. coli to be implicated in human disease; however, no EPEC strain has been fully sequenced until now. Strain E2348/69 (serotype O127:H6 belonging to E. coli phylogroup B2) has been used worldwide as a prototype strain to study EPEC biology, genetics, and virulence. Studies of E2348/69 led to the discovery of the locus of enterocyte effacement-encoded type III secretion system (T3SS) and its cognate effectors, which play a vital role in attaching and effacing lesion formation on gut epithelial cells. In this study, we determined the complete genomic sequence of E2348/69 and performed genomic comparisons with other important E. coli strains. We identified 424 E2348/69-specific genes, most of which are carried on mobile genetic elements, and a number of genetic traits specifically conserved in phylogroup B2 strains irrespective of their pathotypes, including the absence of the ETT2-related T3SS, which is present in E. coli strains belonging to all other phylogroups. The genome analysis revealed the entire gene repertoire related to E2348/69 virulence. Interestingly, E2348/69 contains only 21 intact T3SS effector genes, all of which are carried on prophages and integrative elements, compared to over 50 effector genes in enterohemorrhagic E. coli O157. As E2348/69 is the most-studied pathogenic E. coli strain, this study provides a genomic context for the vast amount of existing experimental data. The unexpected simplicity of the E2348/69 T3SS provides the first opportunity to fully dissect the entire virulence strategy of attaching and effacing pathogens in the genomic context.

  16. Pathogen pollution and the emergence of a deadly amphibian pathogen.

    Science.gov (United States)

    McKenzie, Valerie J; Peterson, Anna C

    2012-11-01

    Imagine a single pathogen that is responsible for mass mortality of over a third of an entire vertebrate class. For example, if a single pathogen were causing the death, decline and extinction of 30% of mammal species (including humans), the entire world would be paying attention. This is what has been happening to the world's amphibians - the frogs, toads and salamanders that are affected by the chytrid fungal pathogen, Batrachochytrium dendrobatidis (referred to as Bd), which are consequently declining at an alarming rate. It has aptly been described as the worst pathogen in history in terms of its effects on biodiversity (Kilpatrick et al. 2010). The pathogen was only formally described about 13 years ago (Longcore et al. 1999), and scientists are still in the process of determining where it came from and investigating the question: why now? Healthy debate has ensued as to whether Bd is a globally endemic organism that only recently started causing high mortality due to shifting host responses and/or environmental change (e.g. Pounds et al. 2006) or whether a virulent strain of the pathogen has rapidly disseminated around the world in recent decades, affecting new regions with a vengeance (e.g. Morehouse et al. 2003; Weldon et al. 2004; Lips et al. 2008). We are finally beginning to shed more light on this question, due to significant discoveries that have emerged as a result of intensive DNA-sequencing methods comparing Bd isolates from different amphibian species across the globe. Evidence is mounting that there is indeed a global panzootic lineage of Bd (BdGPL) in addition to what appear to be more localized endemic strains (Fisher et al. 2009; James et al. 2009; Farrer et al. 2011). Additionally, BdGPL appears to be a hypervirulent strain that has resulted from the hybridization of different Bd strains that came into contact in recent decades, and is now potentially replacing the less-virulent endemic strains of the pathogen (Farrer et al. 2011

  17. Pathogenicity of Shigella in Chickens

    Science.gov (United States)

    Chen, Lu; Chang, Hong-tao; Liu, Hong-ying; Zhao, Jun; Wang, Xin-wei; Wang, Chuan-qing

    2014-01-01

    Shigellosis in chickens was first reported in 2004. This study aimed to determine the pathogenicity of Shigella in chickens and the possibility of cross-infection between humans and chickens. The pathogenicity of Shigella in chickens was examined via infection of three-day-old SPF chickens with Shigella strain ZD02 isolated from a human patient. The virulence and invasiveness were examined by infection of the chicken intestines and primary chicken intestinal epithelial cells. The results showed Shigella can cause death via intraperitoneal injection in SPF chickens, but only induce depression via crop injection. Immunohistochemistry and transmission electron microscopy revealed the Shigella can invade the intestinal epithelia. Immunohistochemistry of the primary chicken intestinal epithelial cells infected with Shigella showed the bacteria were internalized into the epithelial cells. Electron microscopy also confirmed that Shigella invaded primary chicken intestinal epithelia and was encapsulated by phagosome-like membranes. Our data demonstrate that Shigella can invade primary chicken intestinal epithelial cells in vitro and chicken intestinal mucosa in vivo, resulting in pathogenicity and even death. The findings suggest Shigella isolated from human or chicken share similar pathogenicity as well as the possibility of human-poultry cross-infection, which is of public health significance. PMID:24949637

  18. Neuroepigenetic regulation of pathogenic memories

    Directory of Open Access Journals (Sweden)

    Stephanie E. Sillivan

    2015-01-01

    Full Text Available Our unique collection of memories determines our individuality and shapes our future interactions with the world. Remarkable advances into the neurobiological basis of memory have identified key epigenetic mechanisms that support the stability of memory. Various forms of epigenetic regulation at the levels of DNA methylation, histone modification, and noncoding RNAs can modulate transcriptional and translational events required for memory processes. By changing the cellular profile in the brain’s emotional, reward, and memory circuits, these epigenetic modifications have also been linked to perseverant, pathogenic memories. In this review, we will delve into the relevance of epigenetic dysregulation to pathogenic memory mechanisms by focusing on 2 neuropsychiatric disorders perpetuated by aberrant memory associations: substance use disorder and post-traumatic stress disorder. As our understanding improves, neuroepigenetic mechanisms may someday be harnessed to develop novel therapeutic targets for the treatment of these chronic, relapsing disorders.

  19. Antimicrobial resistance of mastitis pathogens.

    Science.gov (United States)

    Oliver, Stephen P; Murinda, Shelton E

    2012-07-01

    Antibiotics are used extensively in the dairy industry to combat disease and to improve animal performance. Antibiotics such as penicillin, cephalosporin, streptomycin, and tetracycline are used for the treatment and prevention of diseases affecting dairy cows caused by a variety of gram-positive and gram-negative bacteria. Antibiotics are often administrated routinely to entire herds to prevent mastitis during the dry period. An increase in the incidence of disease in a herd generally results in increased use of antimicrobials, which in turn increases the potential for antibiotic residues in milk and the potential for increased bacterial resistance to antimicrobials. Continued use of antibiotics in the treatment and prevention of diseases of dairy cows will continue to be scrutinized. It is clear that strategies employing the prudent use of antimicrobials are needed. This clearly illustrates the importance of effective herd disease prevention and control programs. Based on studies published to date, scientific evidence does not support widespread, emerging resistance among mastitis pathogens to antibacterial drugs even though many of these antibiotics have been used in the dairy industry for treatment and prevention of disease for several decades. However, it is clear that use of antibiotics in dairy cows can contribute to increased antimicrobial resistance. While antimicrobial resistance does occur, we are of the opinion that the advantages of using antibiotics for the treatment of mastitis far outweigh the disadvantages. The clinical consequences of antimicrobial resistance of dairy pathogens affecting humans appear small. Antimicrobial resistance among dairy pathogens, particularly those found in milk, is likely not a human health concern as long as the milk is pasteurized. However, there are an increasing number of people who choose to consume raw milk. Transmission of an antimicrobial-resistant mastitis pathogen and/or foodborne pathogen to humans could occur

  20. Virulence factors of Escherichia coli in relation to the importance of vaccination in pigs

    Directory of Open Access Journals (Sweden)

    Daniele Araujo Pereira

    2016-08-01

    Full Text Available ABSTRACT: Enterotoxigenic Escherichia coli (ETEC is the major cause of diarrhea in newborn and weaned pigs. Bacteria adhesion to the host cell is considered a specific phenomenon among fimbrial and non-fimbrial adhesins with their respective receptors on enterocytes. Enteric disorders are related with the fimbriae F4 (K88, F5 (K99, F6 (987P, F41, and F18. In addition to ETEC, another category of E. coli , porcine pathogenic E. coli (PEPEC,can cause diarrhea in pigs; it produces the porcine attaching and effacing-associated (Paa adhesin in, which is capable to cause a typical lesion known as an attaching and effacing (A/E lesion. Immunization of sows with adhesin is important to stimulate the production of antibodies and their subsequent transfer to piglets through colostrum. The aim of this paper is to illustrate the main impacts of enteric diseases caused by E. coli in swine production and to highlight the importance of continuing research on this bacterium to improve disease prevention through vaccination.

  1. Periodontal pathogens in atheromatous plaque

    OpenAIRE

    Saroj K. Rath; Manish Mukherjee; R Kaushik; Sourav Sen; Mukesh Kumar

    2014-01-01

    Background: There has been increasing attention paid in recent years to the possibility that oral bacterial infection, particularly periodontal disease may influence the initiation and or progression of systemic diseases. These studies confirm the observation that heart disease is the most commonly found systemic condition in patients with periodontal disease. Moreover, the literature has also highlighted substantial evidence indicating the presence of Gram-negative periodontal pathogens in a...

  2. Host-Pathogen Coupled Interactions

    Science.gov (United States)

    2015-01-04

    describe bacterial proliferation in the host (and the host’s immune response), and molecular-level models describing the subversion of the molecular...the pathogen is endocytosed by host immune cells, and in the course of infection can escape back into the tissue or bloodstream of the host. During...host’s overall ( immune ) response. 15. SUBJECT TERMS Mathematical model, signaling pathways, bacterial infection, macrophage, immune system 16. SECURITY

  3. Aeromonas Hydrophila: A Re-Emerging Pathogen

    Digital Repository Service at National Institute of Oceanography (India)

    Lakshmanaperumalsamy, P.; Thayumanavan, T.; Subashkumar, R.

    been initiated by their importance as fish pathogens or as a potential pathogen of humans and have, therefore, tended to focus on commercial and sport fisheries and recreational waters. Mesophilic aeromonads are halotolerant and are associated...

  4. Programmed Pathogen Sense and Destroy Circuits

    National Research Council Canada - National Science Library

    Weiss, Ron

    2009-01-01

    We are creating an anti-microbial sense-and-destroy system by engineering sentinel/killer cells that detect the presence of pathogenic bacteria, report the identity of the pathogen with a coded output...

  5. Evolutionary biology of bacterial and fungal pathogens

    National Research Council Canada - National Science Library

    Cassell, Gail H; Gutierrez-Fuentes, Jose A; Barquero, Fernando; Nombela, Cesar

    2008-01-01

    ... and Evolutionary Dynamics of Pathogens * 21 Keith A. Crandall and Marcos Pérez-Losada II. Evolutionary Genetics of Microbial Pathogens 4. Environmental and Social Influences on Infectious Disea...

  6. Secreted proteases from pathogenic fungi.

    Science.gov (United States)

    Monod, Michel; Capoccia, Sabrina; Léchenne, Barbara; Zaugg, Christophe; Holdom, Mary; Jousson, Olivier

    2002-10-01

    Many species of human pathogenic fungi secrete proteases in vitro or during the infection process. Secreted endoproteases belong to the aspartic proteases of the pepsin family, serine proteases of the subtilisin family, and metalloproteases of two different families. To these proteases has to be added the non-pepsin-type aspartic protease from Aspergillus niger and a unique chymotrypsin-like protease from Coccidioides immitis. Pathogenic fungi also secrete aminopeptidases, carboxypeptidases and dipeptidyl-peptidases. The function of fungal secreted proteases and their importance in infections vary. It is evident that secreted proteases are important for the virulence of dermatophytes since these fungi grow exclusively in the stratum corneum, nails or hair, which constitutes their sole nitrogen and carbon sources. The aspartic proteases secreted by Candida albicans are involved in the adherence process and penetration of tissues, and in interactions with the immune system of the infected host. For Aspergillus fumigatus, the role of proteolytic activity has not yet been proved. Although the secreted proteases have been intensively investigated as potential virulence factors, knowledge on protease substrate specificities is rather poor and few studies have focused on the research of inhibitors. Knowledge of substrate specificities will increase our understanding about the action of each protease secreted by pathogenic fungi and will help to determine their contribution to virulence.

  7. Molecular Mechanisms of Bacterial Pathogenicity

    Science.gov (United States)

    Fuchs, Thilo Martin

    Cautious optimism has arisen over recent decades with respect to the long struggle against bacteria, viruses, and parasites. This has been offset, however, by a fatal complacency stemming from previous successes such as the development of antimicrobial drugs, the eradication of smallpox, and global immunization programs. Infectious diseases nevertheless remain the world's leading cause of death, killing at least 17 million persons annually [61]. Diarrheal diseases caused by Vibrio cholerae or Shigella dysenteriae kill about 3 million persons every year, most of them young children: Another 4 million die of tuberculosis or tetanus. Outbreaks of diphtheria in Eastern Europe threatens the population with a disease that had previously seemed to be overcome. Efforts to control infectious diseases more comprehensively are undermined not only by socioeconomic conditions but also by the nature of the pathogenic organisms itself; some isolates of Staphylococcus aureus and Enterobacter have become so resistant to drugs by horizontal gene transfer that they are almost untreatable. In addition, the mechanism of genetic variability helps pathogens to evade the human immune system, thus compromising the development of powerful vaccines. Therefore detailed knowledge of the molecular mechanisms of microbial pathogenicity is absolutely necessary to develop new strategies against infectious diseases and thus to lower their impact on human health and social development.

  8. Minisequencing mitochondrial DNA pathogenic mutations

    Directory of Open Access Journals (Sweden)

    Carracedo Ángel

    2008-04-01

    Full Text Available Abstract Background There are a number of well-known mutations responsible of common mitochondrial DNA (mtDNA diseases. In order to overcome technical problems related to the analysis of complete mtDNA genomes, a variety of different techniques have been proposed that allow the screening of coding region pathogenic mutations. Methods We here propose a minisequencing assay for the analysis of mtDNA mutations. In a single reaction, we interrogate a total of 25 pathogenic mutations distributed all around the whole mtDNA genome in a sample of patients suspected for mtDNA disease. Results We have detected 11 causal homoplasmic mutations in patients suspected for Leber disease, which were further confirmed by standard automatic sequencing. Mutations m.11778G>A and m.14484T>C occur at higher frequency than expected by change in the Galician (northwest Spain patients carrying haplogroup J lineages (Fisher's Exact test, P-value Conclusion We here developed a minisequencing genotyping method for the screening of the most common pathogenic mtDNA mutations which is simple, fast, and low-cost. The technique is robust and reproducible and can easily be implemented in standard clinical laboratories.

  9. Effectiveness of irradiation in killing pathogens

    International Nuclear Information System (INIS)

    Yeager, J.G.; Ward, R.L.

    1980-01-01

    United States Environmental Protection Agency regulations include gamma ray irradiation of sludge as an approved Process to Further Reduce Pathogens (PFRP) prior to land application. Research at Sandia National Laboratories on pathogen inactivation in sludge by gamma irradiation has demonstrated that the 1 Mrad PFRP dose is capable, by itself, of eliminating bacterial, fungal, and parasitic pathogens from sludge. Gamma irradiation of sludge in conjunction with the required Processes to Significantly Reduce Pathogens (PSRP) should also eliminate the viral hazard from wastewater sludges

  10. Functional Characterization of EscK (Orf4), a Sorting Platform Component of the Enteropathogenic Escherichia coli Injectisome.

    Science.gov (United States)

    Soto, Eduardo; Espinosa, Norma; Díaz-Guerrero, Miguel; Gaytán, Meztlli O; Puente, José L; González-Pedrajo, Bertha

    2017-01-01

    The type III secretion system (T3SS) is a supramolecular machine used by many bacterial pathogens to translocate effector proteins directly into the eukaryotic host cell cytoplasm. Enteropathogenic Escherichia coli (EPEC) is an important cause of infantile diarrheal disease in underdeveloped countries. EPEC virulence relies on a T3SS encoded within a chromosomal pathogenicity island known as the locus of enterocyte effacement (LEE). In this work, we pursued the functional characterization of the LEE-encoded protein EscK (previously known as Orf4). We provide evidence indicating that EscK is crucial for efficient T3S and belongs to the SctK (OrgA/YscK/MxiK) protein family, whose members have been implicated in the formation of a sorting platform for secretion of T3S substrates. Bacterial fractionation studies showed that EscK localizes to the inner membrane independently of the presence of any other T3SS component. Combining yeast two-hybrid screening and pulldown assays, we identified an interaction between EscK and the C-ring/sorting platform component EscQ. Site-directed mutagenesis of conserved residues revealed amino acids that are critical for EscK function and for its interaction with EscQ. In addition, we found that T3S substrate overproduction is capable of compensating for the absence of EscK. Overall, our data suggest that EscK is a structural component of the EPEC T3SS sorting platform, playing a central role in the recruitment of T3S substrates for boosting the efficiency of the protein translocation process. The type III secretion system (T3SS) is an essential virulence determinant for enteropathogenic Escherichia coli (EPEC) colonization of intestinal epithelial cells. Multiple EPEC effector proteins are injected via the T3SS into enterocyte cells, leading to diarrheal disease. The T3SS is encoded within a genomic pathogenicity island termed the locus of enterocyte effacement (LEE). Here we unravel the function of EscK, a previously uncharacterized

  11. Host-pathogen interactions during apoptosis

    Indian Academy of Sciences (India)

    Host pathogen interaction results in a variety of responses, which include phagocytosis of the pathogen, release of cytokines, secretion of toxins, as well as production of reactive oxygen species (ROS). Recent studies have shown that many pathogens exert control on the processes that regulate apoptosis in the host.

  12. Comparative transcriptomics of pathogenic and non-pathogenic Listeria species

    Science.gov (United States)

    Wurtzel, Omri; Sesto, Nina; Mellin, J R; Karunker, Iris; Edelheit, Sarit; Bécavin, Christophe; Archambaud, Cristel; Cossart, Pascale; Sorek, Rotem

    2012-01-01

    Listeria monocytogenes is a human, food-borne pathogen. Genomic comparisons between L. monocytogenes and Listeria innocua, a closely related non-pathogenic species, were pivotal in the identification of protein-coding genes essential for virulence. However, no comprehensive comparison has focused on the non-coding genome. We used strand-specific cDNA sequencing to produce genome-wide transcription start site maps for both organisms, and developed a publicly available integrative browser to visualize and analyze both transcriptomes in different growth conditions and genetic backgrounds. Our data revealed conservation across most transcripts, but significant divergence between the species in a subset of non-coding RNAs. In L. monocytogenes, we identified 113 small RNAs (33 novel) and 70 antisense RNAs (53 novel), significantly increasing the repertoire of ncRNAs in this species. Remarkably, we identified a class of long antisense transcripts (lasRNAs) that overlap one gene while also serving as the 5′ UTR of the adjacent divergent gene. Experimental evidence suggests that lasRNAs transcription inhibits expression of one operon while activating the expression of another. Such a lasRNA/operon structure, that we named ‘excludon', might represent a novel form of regulation in bacteria. PMID:22617957

  13. Future research needs involving pathogens in groundwater

    Science.gov (United States)

    Bradford, Scott A.; Harvey, Ronald W.

    2017-06-01

    Contamination of groundwater by enteric pathogens has commonly been associated with disease outbreaks. Proper management and treatment of pathogen sources are important prerequisites for preventing groundwater contamination. However, non-point sources of pathogen contamination are frequently difficult to identify, and existing approaches for pathogen detection are costly and only provide semi-quantitative information. Microbial indicators that are readily quantified often do not correlate with the presence of pathogens. Pathogens of emerging concern and increasing detections of antibiotic resistance among bacterial pathogens in groundwater are topics of growing concern. Adequate removal of pathogens during soil passage is therefore critical for safe groundwater extraction. Processes that enhance pathogen transport (e.g., high velocity zones and preferential flow) and diminish pathogen removal (e.g., reversible retention and enhanced survival) are of special concern because they increase the risk of groundwater contamination, but are still incompletely understood. Improved theory and modeling tools are needed to analyze experimental data, test hypotheses, understand coupled processes and controlling mechanisms, predict spatial and/or temporal variability in model parameters and uncertainty in pathogen concentrations, assess risk, and develop mitigation and best management approaches to protect groundwater.

  14. Complement Evasion by Pathogenic Leptospira.

    Science.gov (United States)

    Fraga, Tatiana Rodrigues; Isaac, Lourdes; Barbosa, Angela Silva

    2016-01-01

    Leptospirosis is a neglected infectious disease caused by spirochetes from the genus Leptospira . Pathogenic microorganisms, notably those which reach the blood circulation such as Leptospira , have evolved multiple strategies to escape the host complement system, which is important for innate and acquired immunity. Leptospira avoid complement-mediated killing through: (i) recruitment of host complement regulators; (ii) acquisition of host proteases that cleave complement proteins on the bacterial surface; and, (iii) secretion of proteases that inactivate complement proteins in the Leptospira surroundings. The recruitment of host soluble complement regulatory proteins includes the acquisition of Factor H (FH) and FH-like-1 (alternative pathway), C4b-binding protein (C4BP) (classical and lectin pathways), and vitronectin (Vn) (terminal pathway). Once bound to the leptospiral surface, FH and C4BP retain cofactor activity of Factor I in the cleavage of C3b and C4b, respectively. Vn acquisition by leptospires may result in terminal pathway inhibition by blocking C9 polymerization. The second evasion mechanism lies in plasminogen (PLG) binding to the leptospiral surface. In the presence of host activators, PLG is converted to enzymatically active plasmin, which is able to degrade C3b, C4b, and C5 at the surface of the pathogen. A third strategy used by leptospires to escape from complement system is the active secretion of proteases. Pathogenic, but not saprophytic leptospires, are able to secrete metalloproteases that cleave C3 (central complement molecule), Factor B (alternative pathway), and C4 and C2 (classical and lectin pathways). The purpose of this review is to fully explore these complement evasion mechanisms, which act together to favor Leptospira survival and multiplication in the host.

  15. Icu Pathogens: A Continuous Challenge

    International Nuclear Information System (INIS)

    Hafeez, A.; Munir, T.; Najeeb, S.; Rehman, S.; Gilani, M.

    2016-01-01

    Objective: To determine the frequency and antibiogram of pathogens in an intensive care unit (ICU). Study Design: Cross-sectional, observational study. Place and Duration of Study: Department of Microbiology, Army Medical College, National University of Science and Technology, Islamabad, from January 2013 to January 2014. Methodology: Clinical samples, received from patients admitted in ICU, were inoculated on various medias like blood agar, chocolate agar, MacConkey agar and urine samples on CLED. These were then incubated at 37 degree C for 24 hours. Isolates were identified by colony morphology, Gram reaction, catalase test, oxidase test. Species identification in case of Gram Negative Rods was done by using API 20E (BioMerieux). Antibiotic susceptibility was done by using modified KirbyBauer disc diffusion technique. Bacterial isolates were prepared and inoculated on Mueller-Hinton agar plates followed by application of various antibiotic disc (Oxoid, UK) as per manufacturer's instructions. The plates were then incubated at 37 degree C aerobically for 18 - 24 hours. Zone diameters were measured and interpreted as sensitive and resistant, according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Results: Out of the 367 positive cultures, 116 (31.08 percent) were Acinetobacter baumanniisusceptible to minocycline and tigecycline followed by Klebsiella pneumoniae (n=71, 16 percent) susceptible to tigecycline and meropenem. Others were Pseudomonas aeruginosa, Escherichia coli Coagulase Negative Staphylococcus, Staphylococcus aureus, Enterococcus spp., Streptococcus spp., Klebsiella oxytoca, Stenotrophomonas maltophilia, and Candida spp. Conclusion: Acinetobacter baumannii was the most frequently isolated pathogen. Most of the cultures yielding pathogens were from respiratory tract samples. Gram negative isolates were multidrug resistant but most were tigecycline and susceptible to meropenem. (author)

  16. COXIELLA BURNETII PATHOGENICITY MOLECULAR BASIS

    Directory of Open Access Journals (Sweden)

    Yu. A. Panferova

    2016-01-01

    Full Text Available Coxiella burnetii is an obligate intracellular gram-negative bacterial pathogen, an ethiological agent of Q-fever, a zoonotic disease, elapsing as an acute (mostly atypical pneumonia or a chronic (mostly endocarditis form. The host range is represented by wide range of mammal, avian and arthropod species, but the main source of human infection are farm animals. The main route of infection is aerosolic. In case of contact with organism pathogen binds with phagocytal monocytic-macrophagal cell line. C. burnetii promotes maturation of specific phagolysosome-like compartment in host cell, called coxiella-containing vacuole, within this vacuole pathogen becames metabolically activated and actively replicates. Coxiella persists as metabolically inactive spore-like form in environment. Internalisation of C. burnetii occurs using actin-mediated phagocytosis and zipper mechanism. After internalization of bacteria maturation of phagolysosome-like compartment and large coxiella-containing vacuole formation occure, and vacuole can occupy nearly the whole cytoplasm of the host cell. Survivance of infected cells is important for chronic infection with C. burnetii. C. burnetii elongate the viability of host cell by two ways: it actively inhibits apoptotic signal cascades and induce pro-survival factors. Exceptthat C. burnetii involves autophagic pathway during coxiella-containing vacuole formation, and induction of autophagy promotes pathogen replication. During infection C. burnetii translocates effector substrates from bacterial cytosole to euca ryotic host cell cytosole using type IV secretion system, where effectors modulate host cell proteins. Overall approximately 130 secreted effectors of type IV transport system, but function of most of them remains unknown to date. Specific sec reted proteins for variety of strains and isolates were identified, confirmed that certain pathotypes of C. burnetii can exist. Identification and

  17. The Autonomous Pathogen Detection System

    Energy Technology Data Exchange (ETDEWEB)

    Dzenitis, J M; Makarewicz, A J

    2009-01-13

    We developed, tested, and now operate a civilian biological defense capability that continuously monitors the air for biological threat agents. The Autonomous Pathogen Detection System (APDS) collects, prepares, reads, analyzes, and reports results of multiplexed immunoassays and multiplexed PCR assays using Luminex{copyright} xMAP technology and flow cytometer. The mission we conduct is particularly demanding: continuous monitoring, multiple threat agents, high sensitivity, challenging environments, and ultimately extremely low false positive rates. Here, we introduce the mission requirements and metrics, show the system engineering and analysis framework, and describe the progress to date including early development and current status.

  18. Antibodies to enterocyte epitopes in celiac disease

    Czech Academy of Sciences Publication Activity Database

    Tučková, Ludmila; Karská, Kamila; Farré, Maria; Rossmann, Pavel; Steiner, L.; Tlaskalová, Helena

    1995-01-01

    Roč. 76, č. 1 (1995), s. 75 ISSN 0090-1229. [International congress of mucosal immunology /8./. San Diego, 17.07.1995-20.07.1995] R&D Projects: GA ČR GA310/93/1093; GA AV ČR IAA720401 Impact factor: 2.088, year: 1995

  19. Ferritin Assembly in Enterocytes of Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Abraham Rosas-Arellano

    2016-02-01

    Full Text Available Ferritins are protein nanocages that accumulate inside their cavity thousands of oxidized iron atoms bound to oxygen and phosphates. Both characteristic types of eukaryotic ferritin subunits are present in secreted ferritins from insects, but here dimers between Ferritin 1 Heavy Chain Homolog (Fer1HCH and Ferritin 2 Light Chain Homolog (Fer2LCH are further stabilized by disulfide-bridge in the 24-subunit complex. We addressed ferritin assembly and iron loading in vivo using novel transgenic strains of Drosophila melanogaster. We concentrated on the intestine, where the ferritin induction process can be controlled experimentally by dietary iron manipulation. We showed that the expression pattern of Fer2LCH-Gal4 lines recapitulated iron-dependent endogenous expression of the ferritin subunits and used these lines to drive expression from UAS-mCherry-Fer2LCH transgenes. We found that the Gal4-mediated induction of mCherry-Fer2LCH subunits was too slow to effectively introduce them into newly formed ferritin complexes. Endogenous Fer2LCH and Fer1HCH assembled and stored excess dietary iron, instead. In contrast, when flies were genetically manipulated to co-express Fer2LCH and mCherry-Fer2LCH simultaneously, both subunits were incorporated with Fer1HCH in iron-loaded ferritin complexes. Our study provides fresh evidence that, in insects, ferritin assembly and iron loading in vivo are tightly regulated.

  20. Dimeric assembly of enterocyte brush border enzymes

    DEFF Research Database (Denmark)

    Danielsen, E M

    1994-01-01

    The noncovalent, dimeric assembly of small intestinal brush border enzymes was studied by sedimentation analysis in density gradients of extracts of pulse-labeled pig jejunal mucosal explants. Like aminopeptidase N (EC 3.4.11.2), sucrase-isomaltase (EC 3.2.1.48-10), aminopeptidase A (EC 3...... appearance of the liposome-reconstituted enzyme [Norén et al. (1986) J. Biol. Chem. 261, 12306-12309], showing only the inner, membrane-anchored domains of the monomers to be in close contact with one another while the outer domains are far apart. In contrast to the other brush border enzymes studied...

  1. Quorum sensing transcriptional regulator QseA is essential for the expression of multiple virulence regulons of enterohemorrhagic Escherichia coli O157:H7

    Science.gov (United States)

    Introduction and Objectives: QseA is one of several transcriptional regulators that regulates the virulence gene expression in enterohemorrhagic Escherichia coli (EHEC) O157:H7 through quorum sensing. QseA has been shown to regulate the expression of the locus of enterocyte effacement (LEE), non-LEE...

  2. Enterohemorrhagic Escherichia coli O157:H7 requires quorum sensing transcriptional regulators QseA and SdiA for colonization and persistence in the bovine intestinal tract

    Science.gov (United States)

    QseA and SdiA are two of several transcriptional regulators that regulate virulence gene expression of enterohemorrhagic Escherichia coli (EHEC) O157:H7 via quorum sensing (QS). QseA regulates the expression of the locus of enterocyte effacement (LEE). LEE encodes for a type III secretion (T3S) sys...

  3. Pathogenic mechanisms in centronuclear myopathies

    Directory of Open Access Journals (Sweden)

    Heinz eJungbluth

    2014-12-01

    Full Text Available Centronuclear myopathies (CNMs are a genetically heterogeneous group of inherited neuromuscular disorders characterized by clinical features of a congenital myopathy and abundant central nuclei as the most prominent histopathological feature. The most common forms of congenital myopathies with central nuclei have been attributed to X-linked recessive mutations in the MTM1 gene encoding myotubularin (X-linked myotubular myopathy, XLMTM, autosomal-dominant mutations in the DNM2 gene encoding dynamin-2 and the BIN1 gene encoding amphiphysin-2 (also named bridging integrator-1, BIN1, or SH3P9, and autosomal-recessive mutations in BIN1, the RYR1 gene encoding the skeletal muscle ryanodine receptor, and the TTN gene encoding titin. Models to study and rescue the affected cellular pathways are now available in yeast, C. elegans, drosophila, zebrafish, mouse and dog. Defects in membrane trafficking have emerged as a key pathogenic mechanisms, with aberrant T-tubule formation, abnormalities of triadic assembly and disturbance of the excitation-contraction machinery the main downstream effects studied to date. Abnormal autophagy has recently been recognized as another important collateral of defective membrane trafficking in different genetic forms of CNM, suggesting an intriguing link to primary disorders of defective autophagy with overlapping histopathological features.The following review will provide an overview of clinical, histopathological and genetic aspects of the CNMs in the context of the key pathogenic mechanism, outline unresolved questions and indicate promising future lines of enquiry.

  4. Viruses of plant pathogenic fungi.

    Science.gov (United States)

    Ghabrial, Said A; Suzuki, Nobuhiro

    2009-01-01

    Mycoviruses are widespread in all major groups of plant pathogenic fungi. They are transmitted intracellularly during cell division, sporogenesis, and cell fusion, but apparently lack an extracellular route for infection. Their natural host ranges are limited to individuals within the same or closely related vegetative compatibility groups. Recent advances, however, allowed the establishment of experimental host ranges for a few mycoviruses. Although the majority of known mycoviruses have dsRNA genomes that are packaged in isometric particles, an increasing number of usually unencapsidated mycoviruses with positive-strand RNA genomes have been reported. We discuss selected mycoviruses that cause debilitating diseases and/or reduce the virulence of their phytopathogenic fungal hosts. Such fungal-virus systems are valuable for the development of novel biocontol strategies and for gaining an insight into the molecular basis of fungal virulence. The availability of viral and host genome sequences and of transformation and transfection protocols for some plant pathogenic fungi will contribute to progress in fungal virology.

  5. Potentially pathogenic, pathogenic, and allergenic moulds in the urban soils

    Directory of Open Access Journals (Sweden)

    Đukić Dragutin A.

    2011-01-01

    Full Text Available The dynamics of soil mould populations that can compromise the human immune system was evaluated in experimental plots located at different distances (100, 300, 500, 700 and 900 m from the main source of pollution - the Podgorica Aluminum Plant. Soil samples were collected in July and October 2008 from three different plot zones at a depth of 0-10 cm. The count of potentially pathogenic, keratinolytic and allergenic (melaninogenic moulds was assessed, which can significantly contribute to both diagnosis and prophylaxis. The count of medically important moulds was higher in the urban soil than in the unpolluted (control soil. Their count decreased with increasing distance from the main pollution source (PAP. Their abundance in the soil was considerably higher in autumn than in spring.

  6. Virulence meets metabolism: Cra and KdpE gene regulation in enterohemorrhagic Escherichia coli.

    Science.gov (United States)

    Njoroge, Jacqueline W; Nguyen, Y; Curtis, Meredith M; Moreira, Cristiano G; Sperandio, Vanessa

    2012-10-16

    Gastrointestinal (GI) bacteria sense diverse environmental signals as cues for differential gene regulation and niche adaptation. Pathogens such as enterohemorrhagic Escherichia coli (EHEC), which causes bloody diarrhea, use these signals for the temporal and energy-efficient regulation of their virulence factors. One of the main virulence strategies employed by EHEC is the formation of attaching and effacing (AE) lesions on enterocytes. Most of the genes necessary for the formation of these lesions are grouped within a pathogenicity island, the locus of enterocyte effacement (LEE), whose expression requires the LEE-encoded regulator Ler. Here we show that growth of EHEC in glycolytic environments inhibits the expression of ler and consequently all other LEE genes. Conversely, growth within a gluconeogenic environment activates expression of these genes. This sugar-dependent regulation is achieved through two transcription factors: KdpE and Cra. Both Cra and KdpE directly bind to the ler promoter, and Cra's affinity to this promoter is catabolite dependent. Moreover, we show that the Cra and KdpE proteins interact in vitro and that KdpE's ability to bind DNA is enhanced by the presence of Cra. Cra is important for AE lesion formation, and KdpE contributes to this Cra-dependent regulation. The deletion of cra and kdpE resulted in the ablation of AE lesions. One of the many challenges that bacteria face within the GI tract is to successfully compete for carbon sources. Linking carbon metabolism to the precise coordination of virulence expression is a key step in the adaptation of pathogens to the GI environment. IMPORTANCE An appropriate and prompt response to environmental cues is crucial for bacterial survival. Cra and KdpE are two proteins found in both nonpathogenic and pathogenic bacteria that regulate genes in response to differences in metabolite concentration. In this work, we show that, in the deadly pathogen enterohemorrhagic Escherichia coli (EHEC) O157:H7

  7. Tracing Boundaries, Effacing Boundaries: Information Literacy as an Academic Discipline

    Science.gov (United States)

    Veach, Grace

    2012-01-01

    Both librarianship and composition have been shaken by recent developments in higher education. In libraries ebooks and online databases threaten the traditional "library as warehouse model," while in composition, studies like The Citation Project show that students are not learning how to incorporate sources into their own writing…

  8. Phosphotyrosine-Mediated Regulation of Enterohemorrhagic Escherichia coli Virulence

    Science.gov (United States)

    Robertson, Colin D.; Hazen, Tracy H.; Kaper, James B.

    2018-01-01

    ABSTRACT Enteric pathogens with low infectious doses rely on the ability to orchestrate the expression of virulence and metabolism-associated genes in response to environmental cues for successful infection. Accordingly, the human pathogen enterohemorrhagic Escherichia coli (EHEC) employs a complex multifaceted regulatory network to link the expression of type III secretion system (T3SS) components to nutrient availability. While phosphorylation of histidine and aspartate residues on two-component system response regulators is recognized as an integral part of bacterial signaling, the involvement of phosphotyrosine-mediated control is minimally explored in Gram-negative pathogens. Our recent phosphotyrosine profiling study of E. coli identified 342 phosphorylated proteins, indicating that phosphotyrosine modifications in bacteria are more prevalent than previously anticipated. The present study demonstrates that tyrosine phosphorylation of a metabolite-responsive LacI/GalR family regulator, Cra, negatively affects T3SS expression under glycolytic conditions that are typical for the colonic lumen environment where production of the T3SS is unnecessary. Our data suggest that Cra phosphorylation affects T3SS expression by modulating the expression of ler, which encodes the major activator of EHEC virulence gene expression. Phosphorylation of the Cra Y47 residue diminishes DNA binding to fine-tune the expression of virulence-associated genes, including those of the locus of enterocyte effacement pathogenicity island that encode the T3SS, and thereby negatively affects the formation of attaching and effacing lesions. Our data indicate that tyrosine phosphorylation provides an additional mechanism to control the DNA binding of Cra and other LacI/GalR family regulators, including LacI and PurR. This study describes an initial effort to unravel the role of global phosphotyrosine signaling in the control of EHEC virulence potential. PMID:29487233

  9. Phosphotyrosine-Mediated Regulation of Enterohemorrhagic Escherichia coli Virulence

    Directory of Open Access Journals (Sweden)

    Colin D. Robertson

    2018-02-01

    Full Text Available Enteric pathogens with low infectious doses rely on the ability to orchestrate the expression of virulence and metabolism-associated genes in response to environmental cues for successful infection. Accordingly, the human pathogen enterohemorrhagic Escherichia coli (EHEC employs a complex multifaceted regulatory network to link the expression of type III secretion system (T3SS components to nutrient availability. While phosphorylation of histidine and aspartate residues on two-component system response regulators is recognized as an integral part of bacterial signaling, the involvement of phosphotyrosine-mediated control is minimally explored in Gram-negative pathogens. Our recent phosphotyrosine profiling study of E. coli identified 342 phosphorylated proteins, indicating that phosphotyrosine modifications in bacteria are more prevalent than previously anticipated. The present study demonstrates that tyrosine phosphorylation of a metabolite-responsive LacI/GalR family regulator, Cra, negatively affects T3SS expression under glycolytic conditions that are typical for the colonic lumen environment where production of the T3SS is unnecessary. Our data suggest that Cra phosphorylation affects T3SS expression by modulating the expression of ler, which encodes the major activator of EHEC virulence gene expression. Phosphorylation of the Cra Y47 residue diminishes DNA binding to fine-tune the expression of virulence-associated genes, including those of the locus of enterocyte effacement pathogenicity island that encode the T3SS, and thereby negatively affects the formation of attaching and effacing lesions. Our data indicate that tyrosine phosphorylation provides an additional mechanism to control the DNA binding of Cra and other LacI/GalR family regulators, including LacI and PurR. This study describes an initial effort to unravel the role of global phosphotyrosine signaling in the control of EHEC virulence potential.

  10. The Candida Pathogenic Species Complex

    Science.gov (United States)

    Turner, Siobhán A.; Butler, Geraldine

    2014-01-01

    Candida species are the most common causes of fungal infection. Approximately 90% of infections are caused by five species: Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis, and Candida krusei. Three (C. albicans, C. tropicalis, and C. parapsilosis) belong to the CTG clade, in which the CTG codon is translated as serine and not leucine. C. albicans remains the most commonly isolated but is decreasing relative to the other species. The increasing incidence of C. glabrata is related to its reduced susceptibility to azole drugs. Genome analysis suggests that virulence in the CTG clade is associated with expansion of gene families, particularly of cell wall genes. Similar independent processes took place in the C. glabrata species group. Gene loss and expansion in an ancestor of C. glabrata may have resulted in preadaptations that enabled pathogenicity. PMID:25183855

  11. Molecular detection of foodborne pathogens

    DEFF Research Database (Denmark)

    Josefsen, Mathilde Hartmann

    of the VBNC state, and would thus be able to assess the outcome and impact of increasingly applied post-slaughter reduction strategies. A real-time PCR-based method for detection of Salmonella was optimized following a diversified approach to enable the shortest time of analysis possible. Positive effects...... of these pathogens in the food chain, in order to improve intervention strategies and make more effective the control of production lines and single food items. To serve this purpose, rapid and reliable detection and quantification methods are imperative. The culture-based standard methods currently applied...... for detection and enumeration of Salmonella and Campylobacter are time-consuming and laborious. They lack specificity and do not enable detection of viable but non-culturable (VBNC) bacteria. The focus of the present thesis has been development and validation of PCR-based detection methods for Salmonella...

  12. Molecular detection of foodborne pathogens

    DEFF Research Database (Denmark)

    Josefsen, Mathilde Hartmann

    .84) was obtained between the Campylobacter counts obtained by PMA-PCR and culture, indicating that the method presents as a reliable tool for producing accurate quantitative data on viable Campylobacter. DNA from dead cells was not detected by the proposed method, however, it recognized the infectious potential...... of these pathogens in the food chain, in order to improve intervention strategies and make more effective the control of production lines and single food items. To serve this purpose, rapid and reliable detection and quantification methods are imperative. The culture-based standard methods currently applied...... for detection and enumeration of Salmonella and Campylobacter are time-consuming and laborious. They lack specificity and do not enable detection of viable but non-culturable (VBNC) bacteria. The focus of the present thesis has been development and validation of PCR-based detection methods for Salmonella...

  13. Peptide Antibiotics for ESKAPE Pathogens

    DEFF Research Database (Denmark)

    Thomsen, Thomas Thyge

    Multi-drug resistance to antibiotics represents a global health challenge that results in increased morbidity and mortality rates. The annual death-toll is >700.000 people world-wide, rising to ~10 million by 2050. New antibiotics are lacking, and few are under development as return on investment...... is considered poor compared to medicines for lifestyle diseases. According to the WHO we could be moving towards a post-antibiotic era in which previously treatable infections become fatal. Of special importance are multidrug resistant bacteria from the ESKAPE group (Enterococcus faecium, Staphylococcus aureus...... and toxicity by utilizing of the fruit fly Drosophila melanogaster as a whole animal model. This was carried out by testing of antimicrobial peptides targeting Gram-positive bacteria exemplified by the important human pathogen methicillin resistant S. aureus (MRSA). The peptide BP214 was developed from...

  14. Molecular diagnostics of foodborne pathogens

    DEFF Research Database (Denmark)

    Hansen, Trine

    or accidental contamination of food, feed and water supplies pose a threat to human health worldwide and the need for generic detection methods that can screen for many pathogens at the time are highly desirable. A metagenomics based direct 16S rDNA sequencing approach was evaluated as a diagnostic tool...... of Salmonellahas an impact on the ability of Salmonellato attach to a pork meat surface and subsequently the possibility of contributing to cross contamination in the slaughter-line. Cells that were grown immobilized prior application on a pork meat surface were found to be more easily removed. In the pork...... processing, Salmonellamight appear in an immobilized state on the pork surfaces where low attachment ability might pose a risk for cross contamination. A stronger attachment to a surface makes on the other hand decontamination steps more difficult. The attachment ability of Salmonellacould to some extend...

  15. Human diseases associated with fish pathogens

    OpenAIRE

    VATSOS N. Ioannis; ANGELIDIS Panagiotis

    2011-01-01

    Until recently, most cases of humans been affected by fish pathogens, bacterial and parasitic, were limited in certain countries, either due to the inappropriate sanitary measures used in those areas, or due to the local habit of eating raw or undercooked fish. However, as new reliable methods to identify fish pathogens in samples collected from sick humans have been developed, the confirmed cases worldwide have increased. The most common fish bacterial pathogens that can affect humans belong...

  16. Heme Synthesis and Acquisition in Bacterial Pathogens

    OpenAIRE

    Choby, Jacob E.; Skaar, Eric P.

    2016-01-01

    Bacterial pathogens require the iron-containing cofactor heme to cause disease. Heme is essential to the function of hemoproteins, which are involved in energy generation by the electron transport chain, detoxification of host immune effectors, and other processes. During infection, bacterial pathogens must synthesize heme or acquire heme from the host; however, host heme is sequestered in high-affinity hemoproteins. Pathogens have evolved elaborate strategies to acquire heme from host source...

  17. Antigenic variation in vector-borne pathogens.

    OpenAIRE

    Barbour, A. G.; Restrepo, B. I.

    2000-01-01

    Several pathogens of humans and domestic animals depend on hematophagous arthropods to transmit them from one vertebrate reservoir host to another and maintain them in an environment. These pathogens use antigenic variation to prolong their circulation in the blood and thus increase the likelihood of transmission. By convergent evolution, bacterial and protozoal vector-borne pathogens have acquired similar genetic mechanisms for successful antigenic variation. Borrelia spp. and Anaplasma marg...

  18. PATHOGENIC PROPERTIES OF INFECTIOUS BURSAL DISEASE VACCINES

    Directory of Open Access Journals (Sweden)

    Iftikhar Hussain, Atif Nisar Ahmad, M. Ashfaque, M.Shahid Mahmood and Masood Akhtar1

    2001-09-01

    Full Text Available The study was conducted to test the pathogenic effect of six commercially available infectious bursal disease (IBD vaccines claimed to be intermediate in their pathogenicity. Three week old chickens were inoculated with these vaccines. The pathogenic effects of the IBD vaccines were evaluated by hemorrhages on the thigh and breast muscles, bursa weight to body weight ratio and virulence; two of the strain were found to be highly virulent; two others were moderate and two could be classified as mild.

  19. Stomata and pathogens: Warfare at the gates

    OpenAIRE

    Gudesblat, Gustavo E; Torres, Pablo S; Vojnov, Adrian A

    2009-01-01

    Bacteria and fungi are capable of triggering stomatal closure through pathogen-associated molecular patterns (PAMPs), which prevents penetration through these pores. Therefore, the stomata can be considered part of the plant innate immune response. Some pathogens have evolved mechanisms to evade stomatal defense. The bacterial pathogen Xanthomonas campestris pv. campestris (Xcc), which infects plants of the Brassicaceae family mainly through hydathodes, has also been reported to infect plants...

  20. Land application of sewage sludge: Pathogen issues

    International Nuclear Information System (INIS)

    Chang, A.C.

    1997-01-01

    Diseases transmitted via the faecal-oral exposure route cause severe gastroenteric disorders, and large numbers of causative organisms are discharged with the faecal matter of infected individuals. For this reason, pathogenic bacteria, viruses, protozoa, or helminths, are always found in sewage sludge. If not properly treated for use in agriculture, sludge can be a source of pathogenic contamination. Radiation is an attractive method to reduce the numbers of microorganisms in sewage sludge. Routine examination for pathogens is not practised nor recommended because complicated and costly procedures are involved. Instead, an indicator organism is usually assayed and enumerated. In this paper, methods are discussed for the investigation of pathogens in sewage sludge. (author)

  1. Sumoylation at the Host-Pathogen Interface

    Directory of Open Access Journals (Sweden)

    Van G. Wilson

    2012-04-01

    Full Text Available Many viral proteins have been shown to be sumoylated with corresponding regulatory effects on their protein function, indicating that this host cell modification process is widely exploited by viral pathogens to control viral activity. In addition to using sumoylation to regulate their own proteins, several viral pathogens have been shown to modulate overall host sumoylation levels. Given the large number of cellular targets for SUMO addition and the breadth of critical cellular processes that are regulated via sumoylation, viral modulation of overall sumoylation presumably alters the cellular environment to ensure that it is favorable for viral reproduction and/or persistence. Like some viruses, certain bacterial plant pathogens also target the sumoylation system, usually decreasing sumoylation to disrupt host anti-pathogen responses. The recent demonstration that Listeria monocytogenes also disrupts host sumoylation, and that this is required for efficient infection, extends the plant pathogen observations to a human pathogen and suggests that pathogen modulation of host sumoylation may be more widespread than previously appreciated. This review will focus on recent aspects of how pathogens modulate the host sumoylation system and how this benefits the pathogen.

  2. Population genomics of fungal and oomycete pathogens

    Science.gov (United States)

    We are entering a new era in plant pathology where whole-genome sequences of many individuals of a pathogen species are becoming readily available. This era of pathogen population genomics will provide new opportunities and challenges, requiring new computational and analytical tools. Population gen...

  3. Immunity to plant pathogens and iron homeostasis.

    Science.gov (United States)

    Aznar, Aude; Chen, Nicolas W G; Thomine, Sebastien; Dellagi, Alia

    2015-11-01

    Iron is essential for metabolic processes in most living organisms. Pathogens and their hosts often compete for the acquisition of this nutrient. However, iron can catalyze the formation of deleterious reactive oxygen species. Hosts may use iron to increase local oxidative stress in defense responses against pathogens. Due to this duality, iron plays a complex role in plant-pathogen interactions. Plant defenses against pathogens and plant response to iron deficiency share several features, such as secretion of phenolic compounds, and use common hormone signaling pathways. Moreover, fine tuning of iron localization during infection involves genes coding iron transport and iron storage proteins, which have been shown to contribute to immunity. The influence of the plant iron status on the outcome of a given pathogen attack is strongly dependent on the nature of the pathogen infection strategy and on the host species. Microbial siderophores emerged as important factors as they have the ability to trigger plant defense responses. Depending on the plant species, siderophore perception can be mediated by their strong iron scavenging capacity or possibly via specific recognition as pathogen associated molecular patterns. This review highlights that iron has a key role in several plant-pathogen interactions by modulating immunity. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. Foliar fungal pathogens and grassland biodiversity

    NARCIS (Netherlands)

    Allan, E.; Ruijven, van J.; Crawley, M.J.

    2010-01-01

    By attacking plants, herbivorous mammals, insects, and belowground pathogens are known to play an important role in maintaining biodiversity in grasslands. Foliar fungal pathogens are ubiquitous in grassland ecosystems, but little is known about their role as drivers of community composition and

  5. 76 FR 24793 - Highly Pathogenic Avian Influenza

    Science.gov (United States)

    2011-05-03

    ... Inspection Service 9 CFR Parts 93, 94, and 95 RIN 0579-AC36 Highly Pathogenic Avian Influenza AGENCY: Animal... products from regions where any subtype of highly pathogenic avian influenza is considered to exist. The... vaccinated for certain types of avian influenza, or that have moved through regions where any subtype of...

  6. Bacterial reproductive pathogens of cats and dogs.

    Science.gov (United States)

    Graham, Elizabeth M; Taylor, David J

    2012-05-01

    With the notable exception of Brucella canis, exogenous bacterial pathogens are uncommon causes of reproductive disease in cats and dogs. Most bacterial reproductive infections are endogenous, and predisposing factors for infection are important. This article reviews the etiology, pathogenesis, clinical presentation, diagnosis, treatment, and public health significance of bacterial reproductive pathogens in cats and dogs.

  7. Arthropods vector grapevine trunk disease pathogens.

    Science.gov (United States)

    Moyo, P; Allsopp, E; Roets, F; Mostert, L; Halleen, F

    2014-10-01

    Arthropod-mediated dispersal of pathogens is known in many cropping systems but has never been demonstrated for grapevine trunk disease pathogens. Arthropods from vineyards were screened for the presence of pathogens associated with Petri disease and esca using cultural and molecular techniques. The ability of the most abundant pathogen-carrying species to inoculate healthy grapevine vascular tissues was also determined. Millipedes and ants were allowed to associate with a DsRed- Express-transformed Phaeomoniella chlamydospora, after which they were exposed to freshly pruned healthy grapevines under controlled conditions and wounds were monitored for subsequent infection. In addition, the possibility of millipede excreta, commonly found on pruning wounds in the field, to act as inoculum source was determined. A diverse arthropod fauna was associated with declining grapevines and many of these carried trunk disease pathogens. However, spiders, the ant Crematogaster peringueyi, and the millipede Ommattoiulus moreleti were the most abundant pathogen carriers. The ant and millipede species fed on pruning wound sap and effectively transmitted trunk disease pathogens. Millipede excreta contained viable spores of Phaeomoniella chlamydospora and may serve as an inoculum source. Numerous arthropods, including beneficial predators, are potential vectors of grapevine trunk disease pathogens. Our results highlight the need for an integrated approach, including targeted management of ants and millipedes at the time of pruning, to limit the spread of grapevine trunk diseases.

  8. Tracing pathogens in the food chain

    NARCIS (Netherlands)

    Brul, S.; Fratamico, P.M.; McMeekin, T.A.

    2010-01-01

    Successful methods for the detection and investigation of outbreaks of foodborne disease are essential for ensuring consumer safety. Increased understanding of the transmission of pathogens in food chains will also assist efforts to safeguard public health. Tracing pathogens in the food chain

  9. Innate host defense against intracellular pathogens

    NARCIS (Netherlands)

    Vaart, Michiel van der

    2013-01-01

    This thesis focuses on the recognition of pathogenic bacteria and the defense mechanisms that are activated during the innate immune response to infection. Detection of pathogens, such as bacteria, viruses, and parasites, depends on receptors that bind to evolutionary conserved structures on their

  10. Pathogens' toolbox to manipulate human complement.

    Science.gov (United States)

    Fernández, Francisco J; Gómez, Sara; Vega, M Cristina

    2017-12-14

    The surveillance and pathogen fighting functions of the complement system have evolved to protect mammals from life-threatening infections. In turn, pathogens have developed complex molecular mechanisms to subvert, divert and evade the effector functions of the complement. The study of complement immunoevasion by pathogens sheds light on their infection drivers, knowledge that is essential to implement therapies. At the same time, complement evasion also acts as a discovery ground that reveals important aspects of how complement works under physiological conditions. In recent years, complex interrelationships between infection insults and the onset of autoimmune and complement dysregulation diseases have led to propose that encounters with pathogens can act as triggering factors for disease. The correct management of these diseases involves the recognition of their triggering factors and the development and administration of complement-associated molecular therapies. Even more recently, unsuspected proteins from pathogens have been shown to possess moonlighting functions as virulence factors, raising the possibility that behind the first line of virulence factors there be many more pathogen proteins playing secondary, helping and supporting roles for the pathogen to successfully establish infections. In an era where antibiotics have a progressively reduced effect on the management and control of infectious diseases worldwide, knowledge on the mechanisms of pathogenic invasion and evasion look more necessary and pressing than ever. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Heme Synthesis and Acquisition in Bacterial Pathogens.

    Science.gov (United States)

    Choby, Jacob E; Skaar, Eric P

    2016-08-28

    Bacterial pathogens require the iron-containing cofactor heme to cause disease. Heme is essential to the function of hemoproteins, which are involved in energy generation by the electron transport chain, detoxification of host immune effectors, and other processes. During infection, bacterial pathogens must synthesize heme or acquire heme from the host; however, host heme is sequestered in high-affinity hemoproteins. Pathogens have evolved elaborate strategies to acquire heme from host sources, particularly hemoglobin, and both heme acquisition and synthesis are important for pathogenesis. Paradoxically, excess heme is toxic to bacteria and pathogens must rely on heme detoxification strategies. Heme is a key nutrient in the struggle for survival between host and pathogen, and its study has offered significant insight into the molecular mechanisms of bacterial pathogenesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Periodontal pathogens in atheromatous plaque.

    Science.gov (United States)

    Rath, Saroj K; Mukherjee, Manish; Kaushik, R; Sen, Sourav; Kumar, Mukesh

    2014-01-01

    There has been increasing attention paid in recent years to the possibility that oral bacterial infection, particularly periodontal disease may influence the initiation and or progression of systemic diseases. These studies confirm the observation that heart disease is the most commonly found systemic condition in patients with periodontal disease. Moreover, the literature has also highlighted substantial evidence indicating the presence of Gram-negative periodontal pathogens in atheromatous plaques. This study intends to investigate the possible association between periodontal health and coronary artery disease by evaluating periodontal status, association between the periodontal plaque and coronary atheromatous plaques for presence of micro-organisms such as, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, and Tannerella forsythia. A case-control study was designed with seven patients who had undergone coronary endarterectomy for cardiovascular disease and 28 controls. The periodontal examination for cases was performed 1 day before vascular surgery and the controls were clinically examined. The atheromatous plaque sample collected during endarterectomy and the intraoral plaque samples were subjected to polymerase chain reaction for identification of A. actinomycetemcomitans, P. gingivalis, P. intermedia and T. forsythia. The presence of periodontal bacteria DNA in coronary atheromatous plaques and sub-gingival plaque samples of the same patients was confirmed by this study. CONCLUSION A correlation was established between putative bacteria contributing to atheromatous plaques and species associated with periodontal disease. One particularly important study to be carried out is the investigation of a possible clinically meaningful reduction in coronary heart disease resulting from the prevention or treatment of periodontal disease.

  13. Quorum Sensing of Periodontal Pathogens.

    Science.gov (United States)

    Plančak, Darije; Musić, Larisa; Puhar, Ivan

    2015-09-01

    The term 'quorum sensing' describes intercellular bacterial communication which regulates bacterial gene expression according to population cell density. Bacteria produce and secrete small molecules, named autoinducers, into the intercellular space. The concentration of these molecules increases as a function of population cell density. Once the concentration of the stimulatory threshold is reached, alteration in gene expression occurs. Gram-positive and Gram-negative bacteria possess different types of quorum sensing systems. Canonical LuxI/R-type/acyl homoserine lactone mediated quorum sensing system is the best studied quorum sensing circuit and is described in Gram-negative bacteria which employ it for inter-species communication mostly. Gram-positive bacteria possess a peptide-mediated quorum sensing system. Bacteria can communicate within their own species (intra-species) but also between species (inter-species), for which they employ an autoinducer-2 quorum sensing system which is called the universal language of the bacteria. Periodontal pathogenic bacteria possess AI-2 quorum sensing systems. It is known that they use it for regulation of biofilm formation, iron uptake, stress response and virulence factor expression. A better understanding of bacterial communication mechanisms will allow the targeting of quorum sensing with quorum sensing inhibitors to prevent and control disease.

  14. Cross-Reactive Protection against Enterohemorrhagic Escherichia coli Infection by Enteropathogenic E. coli in a Mouse Model ▿

    Science.gov (United States)

    Calderon Toledo, Carla; Arvidsson, Ida; Karpman, Diana

    2011-01-01

    Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) are related attaching and effacing (A/E) pathogens. The genes responsible for the A/E pathology are carried on a chromosomal pathogenicity island termed the locus of enterocyte effacement (LEE). Both pathogens share a high degree of homology in the LEE and additional O islands. EHEC prevalence is much lower in areas where EPEC is endemic. This may be due to the development of antibodies against common EPEC and EHEC antigens. This study investigated the hypothesis that EPEC infections may protect against EHEC infections. We used a mouse model to inoculate BALB/c mice intragastrically, first with EPEC and then with EHEC (E. coli O157:H7). Four control groups received either a nonpathogenic E. coli (NPEC) strain followed by EHEC (NPEC/EHEC), phosphate-buffered saline (PBS) followed by EHEC (PBS/EHEC), EPEC/PBS, or PBS/PBS. Mice were monitored for weight loss and symptoms. EPEC colonized the intestine after challenge, and mice developed serum antibodies to intimin and E. coli secreted protein B (encoded in the LEE). Prechallenge with an EPEC strain had a protective effect after EHEC infection, as only a few mice developed mild symptoms, from which they recovered. These mice had an increase in body weight similar to that in control animals, and tissue morphology exhibited mild intestinal changes and normal renal histology. All mice that were not prechallenged with the EPEC strain developed mild to severe symptoms after EHEC infection, with weight loss as well as intestinal and renal histopathological changes. These data suggest that EPEC may protect against EHEC infection in this mouse model. PMID:21402761

  15. Periodontal pathogens in atheromatous plaque

    Directory of Open Access Journals (Sweden)

    Saroj K. Rath

    2014-01-01

    Full Text Available Background: There has been increasing attention paid in recent years to the possibility that oral bacterial infection, particularly periodontal disease may influence the initiation and or progression of systemic diseases. These studies confirm the observation that heart disease is the most commonly found systemic condition in patients with periodontal disease. Moreover, the literature has also highlighted substantial evidence indicating the presence of Gram-negative periodontal pathogens in atheromatous plaques. Aim: This study intends to investigate the possible association between periodontal health and coronary artery disease by evaluating periodontal status, association between the periodontal plaque and coronary atheromatous plaques for presence of micro-organisms such as, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, and Tannerella forsythia. Materials and methods: A case-control study was designed with seven patients who had undergone coronary endarterectomy for cardiovascular disease and 28 controls. The periodontal examination for cases was performed 1 day before vascular surgery and the controls were clinically examined. The atheromatous plaque sample collected during endarterectomy and the intraoral plaque samples were subjected to polymerase chain reaction for identification of A. actinomycetemcomitans, P. gingivalis, P. intermedia and T. forsythia. Results: The presence of periodontal bacteria DNA in coronary atheromatous plaques and sub-gingival plaque samples of the same patients was confirmed by this study. CONCLUSION A correlation was established between putative bacteria contributing to atheromatous plaques and species associated with periodontal disease. One particularly important study to be carried out is the investigation of a possible clinically meaningful reduction in coronary heart disease resulting from the prevention or treatment of periodontal disease.

  16. Efferocytosis of Pathogen-Infected Cells

    Directory of Open Access Journals (Sweden)

    Niloofar Karaji

    2017-12-01

    Full Text Available The prompt and efficient clearance of unwanted and abnormal cells by phagocytes is termed efferocytosis and is crucial for organism development, maintenance of tissue homeostasis, and regulation of the immune system. Dying cells are recognized by phagocytes through pathways initiated via “find me” signals, recognition via “eat me” signals and down-modulation of regulatory “don’t eat me” signals. Pathogen infection may trigger cell death that drives phagocytic clearance in an immunologically silent, or pro-inflammatory manner, depending on the mode of cell death. In many cases, efferocytosis is a mechanism for eliminating pathogens and pathogen-infected cells; however, some pathogens have subverted this process and use efferocytic mechanisms to avoid innate immune detection and assist phagocyte infection. In parallel, phagocytes can integrate signals received from infected dying cells to elicit the most appropriate effector response against the infecting pathogen. This review focuses on pathogen-induced cell death signals that drive infected cell recognition and uptake by phagocytes, and the outcomes for the infected target cell, the phagocyte, the pathogen and the host.

  17. Pathogen webs in collapsing honey bee colonies.

    Directory of Open Access Journals (Sweden)

    R Scott Cornman

    Full Text Available Recent losses in honey bee colonies are unusual in their severity, geographical distribution, and, in some cases, failure to present recognized characteristics of known disease. Domesticated honey bees face numerous pests and pathogens, tempting hypotheses that colony collapses arise from exposure to new or resurgent pathogens. Here we explore the incidence and abundance of currently known honey bee pathogens in colonies suffering from Colony Collapse Disorder (CCD, otherwise weak colonies, and strong colonies from across the United States. Although pathogen identities differed between the eastern and western United States, there was a greater incidence and abundance of pathogens in CCD colonies. Pathogen loads were highly covariant in CCD but not control hives, suggesting that CCD colonies rapidly become susceptible to a diverse set of pathogens, or that co-infections can act synergistically to produce the rapid depletion of workers that characterizes the disorder. We also tested workers from a CCD-free apiary to confirm that significant positive correlations among pathogen loads can develop at the level of individual bees and not merely as a secondary effect of CCD. This observation and other recent data highlight pathogen interactions as important components of bee disease. Finally, we used deep RNA sequencing to further characterize microbial diversity in CCD and non-CCD hives. We identified novel strains of the recently described Lake Sinai viruses (LSV and found evidence of a shift in gut bacterial composition that may be a biomarker of CCD. The results are discussed with respect to host-parasite interactions and other environmental stressors of honey bees.

  18. Pathogen webs in collapsing honey bee colonies.

    Science.gov (United States)

    Cornman, R Scott; Tarpy, David R; Chen, Yanping; Jeffreys, Lacey; Lopez, Dawn; Pettis, Jeffery S; vanEngelsdorp, Dennis; Evans, Jay D

    2012-01-01

    Recent losses in honey bee colonies are unusual in their severity, geographical distribution, and, in some cases, failure to present recognized characteristics of known disease. Domesticated honey bees face numerous pests and pathogens, tempting hypotheses that colony collapses arise from exposure to new or resurgent pathogens. Here we explore the incidence and abundance of currently known honey bee pathogens in colonies suffering from Colony Collapse Disorder (CCD), otherwise weak colonies, and strong colonies from across the United States. Although pathogen identities differed between the eastern and western United States, there was a greater incidence and abundance of pathogens in CCD colonies. Pathogen loads were highly covariant in CCD but not control hives, suggesting that CCD colonies rapidly become susceptible to a diverse set of pathogens, or that co-infections can act synergistically to produce the rapid depletion of workers that characterizes the disorder. We also tested workers from a CCD-free apiary to confirm that significant positive correlations among pathogen loads can develop at the level of individual bees and not merely as a secondary effect of CCD. This observation and other recent data highlight pathogen interactions as important components of bee disease. Finally, we used deep RNA sequencing to further characterize microbial diversity in CCD and non-CCD hives. We identified novel strains of the recently described Lake Sinai viruses (LSV) and found evidence of a shift in gut bacterial composition that may be a biomarker of CCD. The results are discussed with respect to host-parasite interactions and other environmental stressors of honey bees.

  19. Laser inactivation of pathogenic viruses in water

    Science.gov (United States)

    Grishkanich, Alexander; Zhevlakov, Alexander; Kascheev, Sergey; Sidorov, Igor; Ruzankina, Julia; Yakovlev, Alexey; Mak, Andrey

    2016-03-01

    Currently there is a situation that makes it difficult to provide the population with quality drinking water for the sanitary-hygienic requirements. One of the urgent problems is the need for water disinfection. Since the emergence of microorganisms that are pathogens transmitted through water such as typhoid, cholera, etc. requires constant cleansing of waters against pathogenic bacteria. In the water treatment process is destroyed up to 98% of germs, but among the remaining can be pathogenic viruses, the destruction of which requires special handling. As a result, the conducted research the following methods have been proposed for combating harmful microorganisms: sterilization of water by laser radiation and using a UV lamp.

  20. Genetic background affects pathogenicity island function and pathogen emergence in Streptomyces.

    Science.gov (United States)

    Zhang, Yucheng; Jiang, Guangde; Ding, Yousong; Loria, Rosemary

    2018-01-09

    With few exceptions, thaxtomin A (ThxA), a nitrated diketopiperazine, is the pathogenicity determinant for plant-pathogenic Streptomyces species. In Streptomyces scabiei (syn. S. scabies), the ThxA biosynthetic cluster is located within a 177-kb mobile pathogenicity island (PAI), called the toxicogenic region (TR). In S. turgidiscabies, the ThxA biosynthetic cluster is located within a 674-kb pathogenicity island (PAIst). The emergence of new plant pathogens occurs in this genus, but not frequently. This raises the question of whether the mobilization of these pathogenicity regions, through mating, is widespread and whether TR and PAIst can confer plant pathogenicity. We showed that ThxA biosynthetic clusters on TR and PAIst were transferred into strains from five non-pathogenic Streptomyces species through mating with S. scabiei and S. turgidiscabies. However, not all of the transconjugants produced ThxA and exhibited the virulence phenotype, indicating that the genetic background of the recipient strains affects the functionality of the ThxA biosynthetic cluster and therefore would be expected to affect the emergence of novel pathogenic Streptomyces species. Thxs have been patented as natural herbicides, but have yet to be commercialized. Our results also demonstrated the potential of the heterologous production of ThxA as a natural and biodegradable herbicide in non-pathogenic Streptomyces species. © 2018 BSPP AND JOHN WILEY & SONS LTD.

  1. A novel approach for differentiating pathogenic and non-pathogenic Leptospira based on molecular fingerprinting.

    Science.gov (United States)

    Xiao, Di; Zhang, Cuicai; Zhang, Huifang; Li, Xiuwen; Jiang, Xiugao; Zhang, Jianzhong

    2015-04-24

    Leptospirosis is a worldwide, deadly zoonotic disease. Pathogenic Leptospira causes leptospirosis. The rapid and accurate identification of pathogenic and non-pathogenic Leptospira strains is essential for appropriate therapeutic management and timely intervention for infection control. The molecular fingerprint is a simple and rapid alternative tool for microorganisms identification, which is based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). In this study, molecular fingerprint was performed to identify pathogenic strains of Leptospira. Phylogenetic analysis based on 16S rRNA gene sequences was used as the reference method. In addition, a label-free technique was used to reveal the different proteins of pathogenic or non-pathogenic Leptospira. A reference database was constructed using 30 Leptospira strains, including 16 pathogenic strains and 14 non-pathogenic strains. Two super reference spectra that were associated with pathogenicity were established. Overall, 33 Leptospira strains were used for validation, and 32 of 33 Leptospira strains could be identified on the species level and all the 33 could be classified as pathogenic or non-pathogenic. The super reference spectra and the major spectra projection (MSP) dendrogram correctly categorized the Leptospira strains into pathogenic and non-pathogenic groups, which was consistent with the 16S rRNA reference methods. Between the pathogenic and non-pathogenic strains, 108 proteins were differentially expressed. molecular fingerprint is an alternative to conventional molecular identification and can rapidly distinguish between pathogenic and non-pathogenic Leptospira strains. Therefore, molecular fingerprint may play an important role in the clinical diagnosis, treatment, surveillance, and tracking of epidemic outbreaks of leptospirosis. Leptospirosis is a worldwide zoonosis that is caused by spirochetes of the genus Leptospira. Leptospirosis is a serious zoonotic

  2. Novel detection techniques for human pathogens that contaminate poultry.

    Science.gov (United States)

    Mandrell, R E; Wachtel, M R

    1999-06-01

    Poultry products are presumed to be a major contributor to human foodborne illness due to their high frequency of contamination with pathogens Salmonella spp. and Campylobacter spp. This has stimulated the development of more sensitive and rapid methods for identifying pathogens present in poultry. These new methods include immunomagnetic separation of pathogen, PCR amplification of pathogen-specific sequences, pathogen-specific DNA and RNA probes, and identification of pathogen-specific ions by mass spectrometry.

  3. Moraxella catarrhalis: from emerging to established pathogen

    NARCIS (Netherlands)

    C.M. Verduin (Cees); C. Hol; A. Fleer; H. van Dijk (Hans); A.F. van Belkum (Alex)

    2002-01-01

    textabstractMoraxella catarrhalis (formerly known as Branhamella catarrhalis) has emerged as a significant bacterial pathogen of humans over the past two decades. During this period, microbiological and molecular diagnostic techniques have been developed and improved for M.

  4. The making of a new pathogen

    DEFF Research Database (Denmark)

    Stukenbrock, Eva; Bataillon, Thomas; Dutheil, Julien

    2011-01-01

    The fungus Mycosphaerella graminicola emerged as a new pathogen of cultivated wheat during its domestication ~11,000 yr ago. We assembled 12 high-quality full genome sequences to investigate the genetic footprints of selection in this wheat pathogen and closely related sister species that infect...... that gene-rich regions or regions with low recombination experience stronger effects of natural selection on neutral diversity. Emergence of a new agricultural host selected a highly specialized and fast-evolving pathogen with unique evolutionary patterns compared with its wild relatives. The strong impact....... Recent divergence between pathogen sister species is attested by the high degree of incomplete lineage sorting (ILS) in their genomes. We exploit ILS to generate a genetic map of the species without any crossing data, document recent times of species divergence relative to genome divergence, and show...

  5. Pathogen reduction in sludges by irradiation

    International Nuclear Information System (INIS)

    Brandon, J.R.

    1978-01-01

    This paper presents results of pathogen inactivation programs being conducted in Belgium, Czechoslovakia, France, East Germany, West Germany, Hungary, Italy, The Netherlands, Poland, Spain, Sweden, Switzerland, the United Kingdom, and the United States

  6. Genomes of foodborne and waterborne pathogens

    National Research Council Canada - National Science Library

    Fratamico, Pina M; Liu, Yanhong; Kathariou, Sophia

    2011-01-01

    ... of Pathogenic Vibrio cholerae * 85 Salvador Almagro-Moreno, Ronan A. Murphy, and E. Fidelma Boyd 8. Genomics of the Enteropathogenic Yersiniae * 101 Alan McNally, Nicholas R. Thomson, and Brendan W. ...

  7. Promotion and inhibition of mutation in pathogens

    Directory of Open Access Journals (Sweden)

    Maurice Samuel Devaraj

    2014-03-01

    Findings from this research may be used to prevent development of drug resistance, whether epigenetic or arising due to deoxyribonucleic acid (DNA modification, in several pathogens, especially Mycobacterium tuberculosis through the co-administration of adenosine along with antibiotic treatment.

  8. Modulation of pathogen recognition by autophagy

    Directory of Open Access Journals (Sweden)

    Ji Eun eOh

    2012-03-01

    Full Text Available Autophagy is an ancient biological process for maintaining cellular homeostasis by degradation of long-lived cytosolic proteins and organelles. Recent studies demonstrated that autophagy is availed by immune cells to regulate innate immunity. On the one hand, cells exert direct effector function by degrading intracellular pathogens; on the other hand, autophagy modulates pathogen recognition and downstream signaling for innate immune responses. Pathogen recognition via pattern recognition receptors induces autophagy. The function of phagocytic cells is enhanced by recruitment of autophagy-related proteins. Moreover, autophagy acts as a delivery system for viral replication complexes to migrate to the endosomal compartments where virus sensing occurs. In another case, key molecules of the autophagic pathway have been found to negatively regulate immune signaling, thus preventing aberrant activation of cytokine production and consequent immune responses. In this review, we focus on the recent advances in the role of autophagy in pathogen recognition and modulation of innate immune responses.

  9. Surveys for Pathogens of Monoecious Hydrilla 2014

    Science.gov (United States)

    2016-06-01

    monoecious hydrilla management. Fusarium spp.: The genus Fusarium is represented with many necrotrophic plant pathogenic fungi causing disease on...Press Inc.: Boca Raton, FL. Dick, G. O., L. L. Dodd, D. H. Smith, and M. Smart. (In Review ). Native aquatic plant restoration as a component of...74:1035-1036. Joye, G. F., and A. F. Cofrancesco. 1991. Studies on the use of fungal plant pathogens for control of Hydrilla verticillata (L. f

  10. Pathogen Causing Disease of Diagnosis PCR Tecnology

    OpenAIRE

    SEVİNDİK, Emre; KIR, A. Çağrı; BAŞKEMER, Kadir; UZUN, Veysel

    2013-01-01

    Polimerase chain reaction (PCR) with which, the development of recombinant DNA tecnology, a technique commonly used in field of moleculer biology and genetic. Duplication of the target DNA is provided with this technique without the need for cloning. Some fungus species, bacteria, viruses constitutent an important group of pathogenicity in human, animals and plants. There are routinely applied types of PCR in the detection of pathogens infections diseases. These Nested- PCR, Real- Time PCR, M...

  11. Human diseases associated with fish pathogens

    Directory of Open Access Journals (Sweden)

    VATSOS N. Ioannis

    2011-09-01

    Full Text Available Until recently, most cases of humans been affected by fish pathogens, bacterial and parasitic, were limited in certain countries, either due to the inappropriate sanitary measures used in those areas, or due to the local habit of eating raw or undercooked fish. However, as new reliable methods to identify fish pathogens in samples collected from sick humans have been developed, the confirmed cases worldwide have increased. The most common fish bacterial pathogens that can affect humans belong to the genera: Mycobacterium spp. (mainly M. marinum, M. chelonei, M. fortuitum, Nocardia spp., Streptococcus spp (S. iniae, Vibrio spp. (mainly V. vulnificus, V. alginolyticus and V. parahaemolyticus and Aeromonas spp. (mainly A. hydrophila and rarely A. sorbia and A. caviae. Less often, infections of humans with Edwardsiella tarda and Photobacterium damselae sbsp. damselae have been reported. Fish usually act as intermediate hosts to many important parasites of human, as for example the tapeworm Diphyllobothrium latum. To fish, these parasites cause no or little damage, as they are usually found encysted in many fish tissues. Of particular interest are someanisakids (e.g. Anisakis simplex and Pseudoterranova decipiens which can produce some thermostable allergens. Most of the above pathogens can infect humans through skin wounds or after ingesting infected fish. Compromised immune system of the infected humans may result in extensive spread of the pathogens within the body, often causing death.There are no fish viruses or fungi that can affect humans. Fish can also act as carriers for human pathogens, such as Salmonella spp., Escherichia coli and Listeria spp. Recently, few human pathogens have also been isolated from the internal organs of fish, as for example Brucella melitensis. The effects of these human pathogens to fish are still not known.

  12. Aggregatibacter actinomycetemcomitans: Important pathogen in periodontitis

    OpenAIRE

    Ramos Perfecto, Donald; Profesor Auxiliar, Dpto de C. Básicas. Laboratorio de Microbiología UNMSM.; Moromi Nakata, Hilda; Profesor Principal Dpto. de C. Básicas. Laboratorio de Microbiología UNMSM.; Martínez Cadillo, Elba; Profesor Asociado Dpto. de C. Básicas. Laboratorio de Microbiología UNMSM.; Mendoza Rojas, Alejandro; Profesor Principal Dpto. de C. Básicas. Laboratorio de Microbiología UNMSM.

    2014-01-01

    Aggregatibacter actinomycetemcomitans is a pathogen extensively studied in the clinical conditions of the Periodontitis, already identified in the early twentieth century. Over the years it has undergone changes in its denomination and multiple virulence factors that make it an important pathogen in the periodontal disease have been discovered, specifically in the localized Aggressive Periodontitis. This review tries to explain its morphology, virulence factors, culture and other important ch...

  13. Subversion of cell signaling by pathogens.

    Science.gov (United States)

    Alto, Neal M; Orth, Kim

    2012-09-01

    Pathogens exploit several eukaryotic signaling pathways during an infection. They have evolved specific effectors and toxins to hijack host cell machinery for their own benefit. Signaling molecules are preferentially targeted by pathogens because they globally regulate many cellular processes. Both viruses and bacteria manipulate and control pathways that regulate host cell survival and shape, including MAPK signaling, G-protein signaling, signals controlling cytoskeletal dynamics, and innate immune responses.

  14. Sexual Reproduction of Human Fungal Pathogens

    Science.gov (United States)

    Heitman, Joseph; Carter, Dee A.; Dyer, Paul S.; Soll, David R.

    2014-01-01

    We review here recent advances in our understanding of sexual reproduction in fungal pathogens that commonly infect humans, including Candida albicans, Cryptococcus neoformans/gattii, and Aspergillus fumigatus. Where appropriate or relevant, we introduce findings on other species associated with human infections. In particular, we focus on rapid advances involving genetic, genomic, and population genetic approaches that have reshaped our view of how fungal pathogens evolve. Rather than being asexual, mitotic, and largely clonal, as was thought to be prevalent as recently as a decade ago, we now appreciate that the vast majority of pathogenic fungi have retained extant sexual, or parasexual, cycles. In some examples, sexual and parasexual unions of pathogenic fungi involve closely related individuals, generating diversity in the population but with more restricted recombination than expected from fertile, sexual, outcrossing and recombining populations. In other cases, species and isolates participate in global outcrossing populations with the capacity for considerable levels of gene flow. These findings illustrate general principles of eukaryotic pathogen emergence with relevance for other fungi, parasitic eukaryotic pathogens, and both unicellular and multicellular eukaryotic organisms. PMID:25085958

  15. Regulatory T cells and immunity to pathogens.

    Science.gov (United States)

    Rouse, Barry T; Suvas, Susmit

    2007-09-01

    Immune responses to pathogens are modulated by one or more types of cells that perform a regulatory function. Some cells with this function, such as CD4+ Foxp3+ natural regulatory T cells (nTreg), pre-exist prior to infections whereas others may be induced as a consequence of infection (adaptive Treg). With pathogens that have a complex pathogenesis, multiple types of regulatory cells could influence the outcome. One major property of Treg is to help minimize collateral tissue damage that can occur during immune reactions to a chronic infection. The consequence is less damage to the host but in such situations the pathogen is likely to establish persistence. In some cases, a fine balance is established between Treg responses, effector components of immunity and the pathogen. Treg responses to pathogens may also act to hamper the efficacy of immune control. This review discusses these issues as well as the likely mechanisms by which various pathogens can signal the participation of Treg during infection.

  16. Adenoid Reservoir for Pathogenic Biofilm Bacteria▿

    Science.gov (United States)

    Nistico, L.; Kreft, R.; Gieseke, A.; Coticchia, J. M.; Burrows, A.; Khampang, P.; Liu, Y.; Kerschner, J. E.; Post, J. C.; Lonergan, S.; Sampath, R.; Hu, F. Z.; Ehrlich, G. D.; Stoodley, P.; Hall-Stoodley, L.

    2011-01-01

    Biofilms of pathogenic bacteria are present on the middle ear mucosa of children with chronic otitis media (COM) and may contribute to the persistence of pathogens and the recalcitrance of COM to antibiotic treatment. Controlled studies indicate that adenoidectomy is effective in the treatment of COM, suggesting that the adenoids may act as a reservoir for COM pathogens. To investigate the bacterial community in the adenoid, samples were obtained from 35 children undergoing adenoidectomy for chronic OM or obstructive sleep apnea. We used a novel, culture-independent molecular diagnostic methodology, followed by confocal microscopy, to investigate the in situ distribution and organization of pathogens in the adenoids to determine whether pathogenic bacteria exhibited criteria characteristic of biofilms. The Ibis T5000 Universal Biosensor System was used to interrogate the extent of the microbial diversity within adenoid biopsy specimens. Using a suite of 16 broad-range bacterial primers, we demonstrated that adenoids from both diagnostic groups were colonized with polymicrobial biofilms. Haemophilus influenzae was present in more adenoids from the COM group (P = 0.005), but there was no significant difference between the two patient groups for Streptococcus pneumoniae or Staphylococcus aureus. Fluorescence in situ hybridization, lectin binding, and the use of antibodies specific for host epithelial cells demonstrated that pathogens were aggregated, surrounded by a carbohydrate matrix, and localized on and within the epithelial cell surface, which is consistent with criteria for bacterial biofilms. PMID:21307211

  17. Risk factors for drug-resistant pathogens in immunocompetent patients with pneumonia: Evaluation of PES pathogens.

    Science.gov (United States)

    Ishida, Tadashi; Ito, Akihiro; Washio, Yasuyoshi; Yamazaki, Akio; Noyama, Maki; Tokioka, Fumiaki; Arita, Machiko

    2017-01-01

    The new acronym, PES pathogens (Pseudomonas aeruginosa, Enterobacteriaceae extended-spectrum beta-lactamase-positive, and methicillin-resistant Staphylococcus aureus), was recently proposed to identify drug-resistant pathogens associated with community-acquired pneumonia. To evaluate the risk factors for antimicrobial-resistant pathogens in immunocompetent patients with pneumonia and to validate the role of PES pathogens. A retrospective analysis of a prospective observational study of immunocompetent patients with pneumonia between March 2009 and June 2015 was conducted. We clarified the risk factors for PES pathogens. Of the total 1559 patients, an etiological diagnosis was made in 705 (45.2%) patients. PES pathogens were identified in 51 (7.2%) patients, with 53 PES pathogens (P. aeruginosa, 34; ESBL-positive Enterobacteriaceae, 6; and MRSA, 13). Patients with PES pathogens had tendencies toward initial treatment failure, readmission within 30 days, and a prolonged hospital stay. Using multivariate analysis, female sex (adjusted odds ratio [AOR] 1.998, 95% confidence interval [CI] 1.047-3.810), admission within 90 days (AOR 2.827, 95% CI 1.250-6.397), poor performance status (AOR 2.380, 95% CI 1.047-5.413), and enteral feeding (AOR 5.808, 95% CI 1.813-18.613) were independent risk factors for infection with PES pathogens. The area under the receiver operating characteristics curve for the risk factors was 0.66 (95% CI 0.577-0.744). We believe the definition of PES pathogens is an appropriate description of drug-resistant pathogens associated with pneumonia in immunocompetent patients. The frequency of PES pathogens is quite low. However, recognition is critical because they can cause refractory pneumonia and different antimicrobial treatment is required. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  18. The secreted effector protein EspZ is essential for virulence of rabbit enteropathogenic Escherichia coli.

    Science.gov (United States)

    Wilbur, John Scott; Byrd, Wyatt; Ramamurthy, Shylaja; Ledvina, Hannah E; Khirfan, Khaldoon; Riggs, Michael W; Boedeker, Edgar C; Vedantam, Gayatri; Viswanathan, V K

    2015-03-01

    Attaching and effacing (A/E) pathogens adhere intimately to intestinal enterocytes and efface brush border microvilli. A key virulence strategy of A/E pathogens is the type III secretion system (T3SS)-mediated delivery of effector proteins into host cells. The secreted protein EspZ is postulated to promote enterocyte survival by regulating the T3SS and/or by modulating epithelial signaling pathways. To explore the role of EspZ in A/E pathogen virulence, we generated an isogenic espZ deletion strain (ΔespZ) and corresponding cis-complemented derivatives of rabbit enteropathogenic Escherichia coli and compared their abilities to regulate the T3SS and influence host cell survival in vitro. For virulence studies, rabbits infected with these strains were monitored for bacterial colonization, clinical signs, and intestinal tissue alterations. Consistent with data from previous reports, espZ-transfected epithelial cells were refractory to infection-dependent effector translocation. Also, the ΔespZ strain induced greater host cell death than did the parent and complemented strains. In rabbit infections, fecal ΔespZ strain levels were 10-fold lower than those of the parent strain at 1 day postinfection, while the complemented strain was recovered at intermediate levels. In contrast to the parent and complemented mutants, ΔespZ mutant fecal carriage progressively decreased on subsequent days. ΔespZ mutant-infected animals gained weight steadily over the infection period, failed to show characteristic disease symptoms, and displayed minimal infection-induced histological alterations. Terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) staining of intestinal sections revealed increased epithelial cell apoptosis on day 1 after infection with the ΔespZ strain compared to animals infected with the parent or complemented strains. Thus, EspZ-dependent host cell cytoprotection likely prevents epithelial cell death and sloughing and thereby

  19. Secretion of flagellin by the LEE-encoded type III secretion system of enteropathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Kaparakis Maria

    2009-02-01

    Full Text Available Abstract Background Enteropathogenic Escherichia coli (EPEC is an attaching and effacing (A/E pathogen that possesses a type III secretion system (T3SS encoded within the locus of enterocyte effacement (LEE. The LEE is essential for A/E lesion formation and directs the secretion and translocation of multiple LEE-encoded and non-LEE encoded effector proteins into the cytosol of infected cells. In this study we used proteomics to compare proteins exported to the culture supernatant by wild type EPEC E2348/69, a ΔespADB mutant and a ΔescF T3SS mutant. Results We observed that flagellin was consistently and strongly present in the secretome of wild type EPEC and the ΔespADB mutant but present only weakly in the secretome of the ΔescF mutant. Given the ancestral relationship between the flagella export apparatus and virulence associated T3SSs, we investigated whether FliC could utilise the LEE-encoded T3SS for export. In the absence of a functional flagella export apparatus, we showed that FliC could be secreted by the LEE-encoded T3SS and stimulate (Toll-like receptor 5 TLR5 signalling but could not confer motility. Conclusion Since the secretion of FliC during A/E lesion formation would presumably be disadvantageous for the pathogen, we propose that virulence associated T3SSs and flagella T3SSs have evolved through a system of chaperones and complex regulatory pathways to be functional at different times to ensure that FliC secretion does not occur during T3SS effector translocation.

  20. Secretion of flagellin by the LEE-encoded type III secretion system of enteropathogenic Escherichia coli.

    Science.gov (United States)

    Badea, Luminita; Beatson, Scott A; Kaparakis, Maria; Ferrero, Richard L; Hartland, Elizabeth L

    2009-02-06

    Enteropathogenic Escherichia coli (EPEC) is an attaching and effacing (A/E) pathogen that possesses a type III secretion system (T3SS) encoded within the locus of enterocyte effacement (LEE). The LEE is essential for A/E lesion formation and directs the secretion and translocation of multiple LEE-encoded and non-LEE encoded effector proteins into the cytosol of infected cells. In this study we used proteomics to compare proteins exported to the culture supernatant by wild type EPEC E2348/69, a DeltaespADB mutant and a DeltaescF T3SS mutant. We observed that flagellin was consistently and strongly present in the secretome of wild type EPEC and the DeltaespADB mutant but present only weakly in the secretome of the DeltaescF mutant. Given the ancestral relationship between the flagella export apparatus and virulence associated T3SSs, we investigated whether FliC could utilise the LEE-encoded T3SS for export. In the absence of a functional flagella export apparatus, we showed that FliC could be secreted by the LEE-encoded T3SS and stimulate (Toll-like receptor 5) TLR5 signalling but could not confer motility. Since the secretion of FliC during A/E lesion formation would presumably be disadvantageous for the pathogen, we propose that virulence associated T3SSs and flagella T3SSs have evolved through a system of chaperones and complex regulatory pathways to be functional at different times to ensure that FliC secretion does not occur during T3SS effector translocation.

  1. Systematic identification and sequence analysis of the genomic islands of the enteropathogenic Escherichia coli strain B171-8 by the combined use of whole-genome PCR scanning and fosmid mapping.

    Science.gov (United States)

    Ogura, Yoshitoshi; Abe, Hiroyuki; Katsura, Keisuke; Kurokawa, Ken; Asadulghani, Md; Iguchi, Atsushi; Ooka, Tadasuke; Nakayama, Keisuke; Yamashita, Atsushi; Hattori, Masahira; Tobe, Toru; Hayashi, Tetsuya

    2008-11-01

    Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) are diarrheagenic pathogens that colonize the intestinal tract through the formation of attaching and effacing lesions, induced by effectors translocated via a type III secretion system (T3SS) encoded on the locus of enterocyte effacement (LEE). In EHEC O157, numerous virulence factors, including around 40 T3SS effectors, have been identified. Most of them are encoded on genomic islands (GEIs) such as prophages and integrative elements. For EPEC, however, no systematic search of GEIs and virulence-related genes carried therein has been done, and only a limited number of virulence factors have been identified so far. In this study, we performed a systemic and genome-wide survey of the GEIs in strain B171-8, one of the prototype strains of EPEC, by the combined use of whole-genome PCR scanning and fosmid mapping and identified 22 large GEIs, including nine lambda-like prophages, three P2-like prophages, the LEE, and three additional integrative elements. On these prophages and integrative elements, we found genes for a set of T3SS proteins, a total of 33 T3SS effectors or effector homologues, and 12 other virulence factors which include five nonfimbrial adhesins. Most of the T3SS effector families identified are also present in EHEC O157, but B171-8 possesses a significantly smaller number of effectors. Not only the presence or absence of Shiga toxin genes but also the difference in the T3SS effector repertoire should be considered in analyzing the pathogenicity of EPEC and EHEC strains.

  2. More Pathogenicity or Just More Pathogens?—On the Interpretation Problem of Multiple Pathogen Detections with Diagnostic Multiplex Assays

    Directory of Open Access Journals (Sweden)

    Andreas E. Zautner

    2017-06-01

    Full Text Available Modern molecular diagnostic approaches in the diagnostic microbiological laboratory like real-time quantitative polymerase chain reaction (qPCR have led to a considerable increase of diagnostic sensitivity. They usually outperform the diagnostic sensitivity of culture-based approaches. Culture-based diagnostics were found to be insufficiently sensitive for the assessment of the composition of biofilms in chronic wounds and poorly standardized for screenings for enteric colonization with multi-drug resistant bacteria. However, the increased sensitivity of qPCR causes interpretative challenges regarding the attribution of etiological relevance to individual pathogen species in case of multiple detections of facultative pathogenic microorganisms in primarily non-sterile sample materials. This is particularly the case in high-endemicity settings, where continuous exposition to respective microorganisms leads to immunological adaptation and semi-resistance while considerable disease would result in case of exposition of a non-adapted population. While biofilms in chronic wounds show higher pathogenic potential in case of multi-species composition, detection of multiple pathogens in respiratory samples is much more difficult to interpret and asymptomatic enteric colonization with facultative pathogenic microorganisms is frequently observed in high endemicity settings. For respiratory samples and stool samples, cycle-threshold-value-based semi-quantitative interpretation of qPCR results has been suggested. Etiological relevance is assumed if cycle-threshold values are low, suggesting high pathogen loads. Although the procedure is challenged by lacking standardization and methodical issues, first evaluations have led to promising results. Future studies should aim at generally acceptable quantitative cut-off values to allow discrimination of asymptomatic colonization from clinically relevant infection.

  3. Pathogenicity island mobility and gene content.

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Kelly Porter

    2013-10-01

    Key goals towards national biosecurity include methods for analyzing pathogens, predicting their emergence, and developing countermeasures. These goals are served by studying bacterial genes that promote pathogenicity and the pathogenicity islands that mobilize them. Cyberinfrastructure promoting an island database advances this field and enables deeper bioinformatic analysis that may identify novel pathogenicity genes. New automated methods and rich visualizations were developed for identifying pathogenicity islands, based on the principle that islands occur sporadically among closely related strains. The chromosomally-ordered pan-genome organizes all genes from a clade of strains; gaps in this visualization indicate islands, and decorations of the gene matrix facilitate exploration of island gene functions. A %E2%80%9Clearned phyloblocks%E2%80%9D method was developed for automated island identification, that trains on the phylogenetic patterns of islands identified by other methods. Learned phyloblocks better defined termini of previously identified islands in multidrug-resistant Klebsiella pneumoniae ATCC BAA-2146, and found its only antibiotic resistance island.

  4. Susceptibility of pathogenic and nonpathogenic Naegleria ssp

    Energy Technology Data Exchange (ETDEWEB)

    Whiteman, L.Y.

    1988-01-01

    The susceptibility of four species of Naegleria amoebae to complement-mediated lysis was determined. The amoebicidal activity of normal human serum (NHS) and normal guinea pig serum (NGPS) for Naegleria amoebae was measured by an in vitro cytotoxicity assay. Release of radioactivity from amoebae labeled with {sup 3}H-uridine and visual observation with a compound microscope were used as indices of lysis. Susceptibility or resistance to complement-mediated lysis in vitro correlated with the in vivo pathogenic potential. Nonpathogenic Naegleria amoebae were lysed at a faster rate and at higher cell concentrations than were pathogenic amoebae. Electrophoretic analysis of NHS incubated with pathogenic or nonpathogenic Naegleria spp. demonstrated that amoebae activate the complement cascade resulting in the production of C3 and C5 complement cleavage products. Treatment with papain or trypsin for 1 h, but not with sialidase, increase the susceptibility of highly pathogenic, mouse-passaged N. fowleri to lysis. Treatment with actinomycin D, cycloheximide or various protease inhibitors for 4 h did not increase susceptibility to lysis. Neither a repair process involving de novo protein synthesis nor a complement-inactivating protease appear to account for the increase resistance of N. fowleri amoebae to complement-mediated lysis. A binding study with {sup 125}I radiolabeled C9 indicated that the terminal complement component does not remain stably bound to the membrane of pathogenic amoebae.

  5. Stomata and pathogens: Warfare at the gates.

    Science.gov (United States)

    Gudesblat, Gustavo E; Torres, Pablo S; Vojnov, Adrian A

    2009-12-01

    Bacteria and fungi are capable of triggering stomatal closure through pathogen-associated molecular patterns (PAMPs), which prevents penetration through these pores. Therefore, the stomata can be considered part of the plant innate immune response. Some pathogens have evolved mechanisms to evade stomatal defense. The bacterial pathogen Xanthomonas campestris pv. campestris (Xcc), which infects plants of the Brassicaceae family mainly through hydathodes, has also been reported to infect plants through stomata. A recent report shows that penetration of Xcc in Arabidopsis leaves through stomata depends on a secreted small molecule whose synthesis is under control of the rpf/diffusible signal factor (DSF) cell-to-cell signaling system, which also controls genes involved in biofilm formation and pathogenesis. The same reports shows that Arabidopsis ROS- and PAMP-activated MAP kinase 3 (MPK3) is essential for stomatal innate response. Other recent and past findings about modulation of stomatal behaviour by pathogens are also discussed. In all, these findings support the idea that PAMP-triggered stomatal closure might be a more effective and widespread barrier against phytopathogens than previously thought, which has in turn led to the evolution in pathogens of several mechanisms to evade stomatal defense.

  6. Regulatory Proteolysis in Arabidopsis-Pathogen Interactions.

    Science.gov (United States)

    Pogány, Miklós; Dankó, Tamás; Kámán-Tóth, Evelin; Schwarczinger, Ildikó; Bozsó, Zoltán

    2015-09-24

    Approximately two and a half percent of protein coding genes in Arabidopsis encode enzymes with known or putative proteolytic activity. Proteases possess not only common housekeeping functions by recycling nonfunctional proteins. By irreversibly cleaving other proteins, they regulate crucial developmental processes and control responses to environmental changes. Regulatory proteolysis is also indispensable in interactions between plants and their microbial pathogens. Proteolytic cleavage is simultaneously used both by plant cells, to recognize and inactivate invading pathogens, and by microbes, to overcome the immune system of the plant and successfully colonize host cells. In this review, we present available results on the group of proteases in the model plant Arabidopsis thaliana whose functions in microbial pathogenesis were confirmed. Pathogen-derived proteolytic factors are also discussed when they are involved in the cleavage of host metabolites. Considering the wealth of review papers available in the field of the ubiquitin-26S proteasome system results on the ubiquitin cascade are not presented. Arabidopsis and its pathogens are conferred with abundant sets of proteases. This review compiles a list of those that are apparently involved in an interaction between the plant and its pathogens, also presenting their molecular partners when available.

  7. Human pathogen subversion of antigen presentation.

    Science.gov (United States)

    Brodsky, F M; Lem, L; Solache, A; Bennett, E M

    1999-04-01

    Many pathogens have co-evolved with their human hosts to develop strategies for immune evasion that involve disruption of the intracellular pathways by which antigens are bound by class I and class II molecules of the major histocompatibility complex (MHC) for presentation to T cells. Here the molecular events in these pathways are reviewed and pathogen interference is documented for viruses, extracellular and intracellular bacteria and intracellular parasites. In addition to a general review, data from our studies of adenovirus, Chlamydia trachomatis and Coxiella burnetii are summarized. Adenovirus E19 is the first viral gene product described that affects class I MHC molecule expression by two separate mechanisms, intracellular retention of the class I heavy chain by direct binding and by binding to the TAP transporter involved in class I peptide loading. Coxiella and Chlamydia both affect peptide presentation by class II MHC molecules as a result of their residence in endocytic compartments, although the properties of the parasitophorous vacuoles they form are quite different. These examples of active interference with antigen presentation by viral gene products and passive interference by rickettsiae and bacteria are typical of the strategies used by these different classes of pathogens, which need to evade different types of immune responses. Pathogen-host co-evolution is evident in these subversion tactics for which the pathogen crime seems tailored to fit the immune system punishment.

  8. Priority setting of foodborne pathogens: disease burden and costs of selected enteric pathogens

    NARCIS (Netherlands)

    Kemmeren JM; Mangen MJJ; Duynhoven YTHP van; Havelaar AH; MGB

    2006-01-01

    Toxoplasmosis causes the highest disease burden among seven evaluated foodborne pathogens. This is the preliminary conclusion of a major study of the disease burden and related costs of foodborne pathogens. The other micro-organisms that were studied are Campylobacter spp., Salmonella spp.,

  9. Immune Evasion Strategies of Pathogens in Macrophages: the Potential for Limiting Pathogen Transmission.

    Science.gov (United States)

    Ren, Yuwei; Khan, Faheem Ahmed; Pandupuspitasari, Nuruliarizki Shinta; Zhang, Shujun

    2017-01-01

    Preventing pathogen transmission to a new host is of major interest to the immunologist and could benefit from a detailed investigation of pathogen immune evasion strategies. The first line of defense against pathogen invasion is provided by macrophages. When they sense pathogens, macrophages initiate signals to inflammatory and pro-inflammatory cytokines through pattern recognition receptors (PRRs) subsequently mediating phagocytosis and inflammation. The macrophage immune machinery classically includes two subsets: the activated M1 and the activated M2 that respond accordingly in diverse immune challenges. The lipid and glycogen metabolic pathways work together with the lysosome to help the mature phagosome to degrade and eliminate intracellular pathogens in macrophages. The viral evasion strategies are even more complex due to the interplay between autophagy and apoptosis. However, pathogens evolve several strategies to camouflage themselves against immune responses in order to ensure their survival, replication and transmission. These strategies include the muting of PRRs initiated inflammatory responses, attenuation of M1 and/or induction of M2 macrophages, suppression of autophago-lysosomal formation, interference with lipid and glycogen metabolism, and viral mediation of autophagy and apoptosis cross-talk to enhance viral replication. This review focuses on pathogen immune evasion methods and on the strategies used by the host against camouflaged pathogens.

  10. Molecular mechanisms of pathogenicity: how do pathogenic microorganisms develop cross-kingdom host jumps?

    NARCIS (Netherlands)

    Baarlen, P. van; Belkum, A. van; Summerbell, R.C.; Crous, P.W.; Thomma, B.P.

    2007-01-01

    It is common knowledge that pathogenic viruses can change hosts, with avian influenza, the HIV, and the causal agent of variant Creutzfeldt-Jacob encephalitis as well-known examples. Less well known, however, is that host jumps also occur with more complex pathogenic microorganisms such as bacteria

  11. Methods for detecting pathogens in the beef food chain: detecting particular pathogens

    Science.gov (United States)

    The main food-borne pathogens of concern in the beef food chain are Shiga toxin-producing Escherichia coli (STEC) and Salmonella spp.; however, the presence of other pathogens, including Listeria monocytogenes, Campylobacter spp., Clostridium spp., Bacillus cereus, and Mycobacterium avium subsp. par...

  12. Advancing waterborne pathogen modelling: lessons from global nutrient export models

    NARCIS (Netherlands)

    Vermeulen, L.C.; Hofstra, N.; Kroeze, C.; Medema, G.J.

    2015-01-01

    Waterborne pathogens cause health problems worldwide. A global waterborne pathogen model could provide valuable new insights for data-sparse regions, by identifying pathogen hotspots and evaluating global change and risk management scenarios. Global waterborne pathogen modelling is not as advanced

  13. Adenylate cyclases involvement in pathogenicity, a minireview.

    Science.gov (United States)

    Costache, Adriana; Bucurenci, Nadia; Onu, Adrian

    2013-01-01

    Cyclic AMP (cAMP), one of the most important secondary messengers, is produced by adenylate cyclase (AC) from adenosine triphosphate (ATP). AC is a widespread enzyme, being present both in prokaryotes and eukaryotes. Although they have the same enzymatic activity (ATP cyclization), the structure of these proteins varies, depending on their function and the producing organism. Some pathogenic bacteria utilize these enzymes as toxins which interact with calmodulin (or another eukaryote activator), causing intense cAMP synthesis and disruption of infected cell functions. In contrast, other pathogenic bacteria benefit of augmentation of AC activity for their own function. Based on sequence analysis ofAC catalytic domain from two pathogenic bacteria (Bacillus anthracis and Bordetellapertussis) with known three-dimensional structures, a possible secondary structure for 1-255 amino acid fragment from Pseudomonas aeruginosa AC (with 80TKGFSVKGKSS90 as the ATP binding site) is proposed.

  14. Molecular techniques for characterisation of pathogens

    DEFF Research Database (Denmark)

    Kampmann, Marie-Louise

    Pathogens have always had a major interest to humans due to their central role in sickness and death. Influenza A annually kills at least 250,000 humans, and has been the cause of millions of further deaths during pandemic years in the past. Plague (Yersinia pestis) has been the cause of the Black...... Death that was leading to the desertion of whole cities, and as a result was for centuries one of the most feared events in human life. For both of these organisms we generally have situations with only very small amounts of pathogen nucleic acids available, usually because many interesting samples...... capture for the detection of Y. pestis in samples from the Justinian plague (600 AD) as an attempt to detect this pathogen as a cause of death in the victims....

  15. Biocontrol of Pathogens in the Meat Chain

    Science.gov (United States)

    Burgess, Catherine M.; Rivas, Lucia; McDonnell, Mary J.; Duffy, Geraldine

    Bacterial foodborne zoonotic diseases are of major concern, impacting public health and causing economic losses for the agricultural-food sector and the wider society. In the United States (US) alone foodborne illness from pathogens is responsible for 76 million cases of illnesses each year (Mead et al., 1999). Salmonella, Campylobacter jejuni and Enterohaemorraghic Escherichia coli (EHEC; predominately serotype O157:H7) and Listeria monocytogenes are the most predominant foodborne bacterial pathogens reported in the developed world (United States Department of Agriculture, 2001). The importance of meat and meat products as a vehicle of foodborne zoonotic pathogens cannot be underestimated (Center for Disease Control, 2006; Gillespie, O’Brien, Adak, Cheasty, & Willshaw, 2005; Mazick, Ethelberg, Nielsen, Molbak, & Lisby, 2006; Mead et al., 2006).

  16. Expression Study of Banana Pathogenic Resistance Genes

    Directory of Open Access Journals (Sweden)

    Fenny M. Dwivany

    2016-10-01

    Full Text Available Banana is one of the world's most important trade commodities. However, infection of banana pathogenic fungi (Fusarium oxysporum race 4 is one of the major causes of decreasing production in Indonesia. Genetic engineering has become an alternative way to control this problem by isolating genes that involved in plant defense mechanism against pathogens. Two of the important genes are API5 and ChiI1, each gene encodes apoptosis inhibitory protein and chitinase enzymes. The purpose of this study was to study the expression of API5 and ChiI1 genes as candidate pathogenic resistance genes. The amplified fragments were then cloned, sequenced, and confirmed with in silico studies. Based on sequence analysis, it is showed that partial API5 gene has putative transactivation domain and ChiI1 has 9 chitinase family GH19 protein motifs. Data obtained from this study will contribute in banana genetic improvement.

  17. [RAPD analysis of plant pathogenic coryneform bacteria].

    Science.gov (United States)

    Yin, Yan-Ni; Chen, Yong-Fang; Li, Shi-Mo; Guo, Jian-Hua

    2005-12-01

    RAPD analysis was used for the taxonomy of plant pathogenic coryneform bacteria, especially for the classification of two new pathogens (Curtobacterium flaccumfaciens pv. basellae pv. nov. and Curtobacterium flaccumfaciens pv. beticola pv. nov.). 20 random primers were screened from 50 ones to detect polymorphism among the total strains used. 80.4% were polymorphic bands among the 225 ones produced. The results of pairwise similarity and UPGMA cluster analysis suggest that the two new pathovars of sugar beet (Beta vulgaris var. saccharifera) and malabar spinach (Basella rubra) are genetically close related with Curtobacterium flacumfaciens, and the minimal similarity coefficient is 0.6511. According to the RAPD analysis and previous research, some newly made taxonomic changes of the plant pathogenic coryneform bacteria are discussed.

  18. Photoinactivation of major bacterial pathogens in aquaculture

    Directory of Open Access Journals (Sweden)

    Heyong Jin Roh

    2016-08-01

    Full Text Available Abstract Background Significant increases in the bacterial resistance to various antibiotics have been found in fish farms. Non-antibiotic therapies for infectious diseases in aquaculture are needed. In recent years, light-emitting diode technology has been applied to the inactivation of pathogens, especially those affecting humans. The purpose of this study was to assess the effect of blue light (wavelengths 405 and 465 nm on seven major bacterial pathogens that affect fish and shellfish important in aquaculture. Results We successfully demonstrate inactivation activity of a 405/465-nm LED on selected bacterial pathogens. Although some bacteria were not fully inactivated by the 465-nm light, the 405-nm light had a bactericidal effect against all seven pathogens, indicating that blue light can be effective without the addition of a photosensitizer. Photobacterium damselae, Vibrio anguillarum, and Edwardsiella tarda were the most susceptible to the 405-nm light (36.1, 41.2, and 68.4 J cm−2, respectively, produced one log reduction in the bacterial populations, whereas Streptococcus parauberis was the least susceptible (153.8 J cm−2 per one log reduction. In general, optical density (OD values indicated that higher bacterial densities were associated with lower inactivating efficacy, with the exception of P. damselae and Vibrio harveyi. In conclusion, growth of the bacterial fish and shellfish pathogens evaluated in this study was inactivated by exposure to either the 405- or 465-nm light. In addition, inactivation was dependent on exposure time. Conclusions This study presents that blue LED has potentially alternative therapy for treating fish and shellfish bacterial pathogens. It has great advantages in aspect of eco-friendly treating methods differed from antimicrobial methods.

  19. Adhesive threads of extraintestinal pathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Antão Esther-Maria

    2009-12-01

    Full Text Available Abstract The ability to adhere to host surfaces is by far the most vital step in the successful colonization by microbial pathogens. Colonization begins with the attachment of the bacterium to receptors expressed by cells forming the lining of the mucosa. Long hair like extracellular appendages called fimbriae, produced by most Gram-negative pathogens, mediate specific attachment to the epithelial cell surface. Associated with the fimbriae is a protein called an adhesin, which directs high-affinity binding to specific cell surface components. In the last couple of years, an enormous amount of research has been undertaken that deals with understanding how bacterial pathogens adhere to host cells. E. coli in all probability is one of the best studied free-living organisms. A group of E. coli called Extraintestinal pathogenic E. coli (ExPEC including both human and animal pathogens like Uropathogenic E. coli (UPEC, Newborn meningitic E. coli (NMEC and Avian pathogenic E. coli (APEC, have been found to harbour many fimbriae including Type 1 fimbriae, P fimbriae, curli fibres, S fimbriae, F1C fimbriae, Dr fimbriae, afimbrial adhesins, temperature-sensitive haemagglutinin and many novel adhesin gene clusters that have not yet been characterized. Each of these adhesins is unique due to the recognition of an adhesin-specific receptor, though as a group these adhesins share common genomic organization. A newly identified putative adhesin temporarily termed ExPEC Adhesin I, encoded by gene yqi, has been recently found to play a significant role in the pathogenesis of APEC infection, thus making it an interesting candidate for future research. The aim of this review is to describe the role of ExPEC adhesins during extraintestinal infections known till date, and to suggest the idea of investigating their potential role in the colonization of the host gut which is said to be a reservoir for ExPEC.

  20. Interkingdom Chemical Signaling in Enterohemorrhagic Escherichia coli O157:H7.

    Science.gov (United States)

    Kendall, Melissa M

    2016-01-01

    Escherichia coli is one of the most-studied species of bacteria due to its frequent incidence in diverse environments and hosts, as well as its use as a tool in molecular biology. Most E. coli strains are commensal, in that they colonize the host without causing disease; however, some strains of E. coli are pathogens and are able to cause diverse illnesses, including urinary tract infections, sepsis/meningitis, as well as intestinal disease that result in diarrhea (Kaper et al. 2004). Six categories of diarrheagenic E. coli are recognized, and these are classified in part based on how they interact with epithelial cells (Kaper et al. 2004). Of these, enterohemorrhagic E. coli O157:H7 (EHEC) is one of the most important pathogenic E. coli strains. EHEC causes major outbreaks of bloody diarrhea that can result in the development of fatal hemorrhagic colitis and hemolytic uremic syndrome (Karmali et al. 1983). EHEC colonizes the colon, where it forms attaching and effacing (AE) lesions on the intestinal epithelial cell. AE lesions are characterized by intimate attachment of EHEC to epithelial cells, effacement of the microvilli and rearrangement of the underlying cytoskeleton, which results in formation of a pedestal-like structure beneath the bacterium (Jerse et al. 1990; Jarvis et al. 1995; Kenny et al. 1997). Most of the genes involved in the formation of AE lesions are encoded within a chromosomal pathogenicity island termed the locus of enterocyte effacement (LEE) (McDaniel et al. 1995). The LEE contains 41 genes that are organized in five major operons (LEE1, LEE2, LEE3, LEE5, and LEE4) (Elliott et al. 1998, 1999; Mellies et al. 1999). The LEE encodes a type three secretion system (T3SS) (Jarvis et al. 1995), an adhesin (intimin) (Jerse et al. 1990) and its receptor (Tir) (Kenny et al. 1997), as well as effector proteins (Kenny et al. 1996; Abe et al. 1997; McNamara and Donnenberg 1998; Elliott et al. 2001; Tu et al. 2003; Kanack et al. 2005). EHEC also encodes

  1. Differentiation between a pathogenic and a non-pathogenic form of Gyrodactylus salaris using PCR-RFLP

    DEFF Research Database (Denmark)

    Kania, Per Walther; Jørgensen, Thomas Rohde; Buchmann, Kurt

    2007-01-01

    A new method based on PCR-RFLP is presented. It is able to differentiate between the Danish non-pathogenic form of Gyrodactylus salaris and the Norwegian pathogenic form.......A new method based on PCR-RFLP is presented. It is able to differentiate between the Danish non-pathogenic form of Gyrodactylus salaris and the Norwegian pathogenic form....

  2. Emerging pathogens: Dynamics, mutation and drug resistance

    Energy Technology Data Exchange (ETDEWEB)

    Perelson, A.S.; Goldstein, B.; Korber, B.T. [and others

    1997-10-01

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The objectives of this project were to develop models of the spread of pathogens, such as HIV-1 and influenza, in humans, and then to use the models to address the possibility of designing appropriate drug therapies that may limit the ability of the pathogen to escape treatment by mutating into a drug resistant form. We have developed a model of drug-resistance to amantidine and rimantadine, the two major antiviral drugs used to treat influenza, and have used the model to suggest treatment strategies during an epidemic.

  3. Molecular techniques for characterisation of pathogens

    DEFF Research Database (Denmark)

    Kampmann, Marie-Louise

    Pathogens have always had a major interest to humans due to their central role in sickness and death. Influenza A annually kills at least 250,000 humans, and has been the cause of millions of further deaths during pandemic years in the past. Plague (Yersinia pestis) has been the cause of the Black...... capture for the detection of Y. pestis in samples from the Justinian plague (600 AD) as an attempt to detect this pathogen as a cause of death in the victims....

  4. Pathogenic Mechanisms of Cryptosporidium and Giardia.

    Science.gov (United States)

    Certad, Gabriela; Viscogliosi, Eric; Chabé, Magali; Cacciò, Simone M

    2017-07-01

    Intestinal protozoa are important etiological agents of diarrhea, particularly in children, yet the public health risk they pose is often neglected. Results from the Global Enteric Multicenter Study (GEMS) showed that Cryptosporidium is among the leading causes of moderate to severe diarrhea in children under 2 years. Likewise, Giardia infects approximately 200 million individuals worldwide, and causes acute diarrhea in children under 5 years. Despite this recognized role as pathogens, the question is why and how these parasites cause disease in some individuals but not in others. This review focuses on known pathogenic mechanisms of Cryptosporidium and Giardia, and infection progress towards disease. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Viruses - from pathogens to vaccine carriers.

    Science.gov (United States)

    Small, Juliana C; Ertl, Hildegund C J

    2011-10-01

    Vaccination is mankind's greatest public health success story. By now vaccines to many of the viruses that once caused fatal childhood diseases are routinely used throughout the world. Traditional methods of vaccine development through inactivation or attenuation of viruses have failed for some of the most deadly human pathogens, necessitating new approaches. Genetic modification of viruses not only allows for their attenuation but also for incorporation of sequences from other viruses, turning one pathogen into a vaccine carrier for another. Recombinant viruses have pros and cons as vaccine carriers, as discussed below using vectors based on adenovirus, herpesvirus, flavivirus, and rhabdovirus as examples.

  6. Plant-pathogen interactions and elevated CO2: morphological changes in favour of pathogens.

    Science.gov (United States)

    Lake, Janice Ann; Wade, Ruth Nicola

    2009-01-01

    Crop losses caused by pests and weeds have been estimated at 42% worldwide, with plant pathogens responsible for almost $10 billion worth of damage in the USA in 1994 alone. Elevated carbon dioxide [ECO(2)] and associated climate change have the potential to accelerate plant pathogen evolution, which may, in turn, affect virulence. Plant-pathogen interactions under increasing CO(2) concentrations have the potential to disrupt both agricultural and natural systems severely, yet the lack of experimental data and the subsequent ability to predict future outcomes constitutes a fundamental knowledge gap. Furthermore, nothing is known about the mechanistic bases of increasing pathogen agressiveness. In the absence of information on crop species, it is shown here that plant pathogen (Erysiphe cichoracearum) aggressiveness is increased under ECO(2), together with changes in the leaf epidermal characteristics of the model plant Arabidopsis thaliana L. Stomatal density, guard cell length, and trichome numbers on leaves developing post-infection are increased under ECO(2) in direct contrast to non-infected responses. As many plant pathogens utilize epidermal features for successful infection, these responses provide a positive feedback mechanism facilitating an enhanced susceptibility of newly developed leaves to further pathogen attack. Furthermore, a screen of resistant and susceptible ecotypes suggest inherent differences in epidermal responses to ECO(2).

  7. Plant–pathogen interactions and elevated CO2: morphological changes in favour of pathogens

    Science.gov (United States)

    Lake, Janice Ann; Wade, Ruth Nicola

    2009-01-01

    Crop losses caused by pests and weeds have been estimated at 42% worldwide, with plant pathogens responsible for almost $10 billion worth of damage in the USA in 1994 alone. Elevated carbon dioxide [ECO2] and associated climate change have the potential to accelerate plant pathogen evolution, which may, in turn, affect virulence. Plant–pathogen interactions under increasing CO2 concentrations have the potential to disrupt both agricultural and natural systems severely, yet the lack of experimental data and the subsequent ability to predict future outcomes constitutes a fundamental knowledge gap. Furthermore, nothing is known about the mechanistic bases of increasing pathogen agressiveness. In the absence of information on crop species, it is shown here that plant pathogen (Erysiphe cichoracearum) aggressiveness is increased under ECO2, together with changes in the leaf epidermal characteristics of the model plant Arabidopsis thaliana L. Stomatal density, guard cell length, and trichome numbers on leaves developing post-infection are increased under ECO2 in direct contrast to non-infected responses. As many plant pathogens utilize epidermal features for successful infection, these responses provide a positive feedback mechanism facilitating an enhanced susceptibility of newly developed leaves to further pathogen attack. Furthermore, a screen of resistant and susceptible ecotypes suggest inherent differences in epidermal responses to ECO2. PMID:19470658

  8. Development of a multi-pathogen enrichment broth for simultaneous growth of five common foodborne pathogens.

    Science.gov (United States)

    Chen, Juan; Tang, Junni; Bhunia, Arun K; Tang, Cheng; Wang, Changting; Shi, Hui

    2015-01-01

    The objective of the present study was to formulate a multi-pathogen enrichment broth which could support the simultaneous growth of five common foodborne pathogens (Salmonella enterica, Staphylococcus aureus, Shigella flexneri, Listeria monocytogenes and Escherichia coli O157:H7). The formulated broth SSSLE was composed of potassium tellurite, bile salt, lithium chloride, and sodium chloride as growth-inhibitors; glucose, esculin, mannitol and sodium pyruvate as growth-promoters. Compared with the respective specific selective enrichment broths, the individual growth pattern of each target pathogen in SSSLE was equal, or even better, except in the case of S. flexneri. In mixed-culture experiments, the gram-negative bacteria showed higher growth capabilities than the gram-positive bacteria after 8-h enrichment; however, the cell numbers after 24-h enrichment indicated that SSSLE could support the concurrent growth of five target pathogens irrespective of whether pathogens were inoculated initially at equal or unequal levels. For natural food samples under the high background flora, the final cell numbers enriched in SSSLE for five targets were enough to be detected by multiplex PCR. In conclusion, SSSLE was capable of supporting the growth of five target pathogens concurrently. The new broth formulated in this study has the potential of saving time, efforts and costs in multi-pathogen enrichment procedures.

  9. Novel Micro-organisms controlling plant pathogens

    NARCIS (Netherlands)

    Köhl, J.

    2009-01-01

    The invention relates to control of pathogen caused diseases on leaves, fruits and ears in plants, such as apple scab (Venturia inaequalis by treatment of plant with an isolate of Cladosporium cladosporioides. The treatment is effective in both prevention and treatment of the fungal infection

  10. Novel Micro-organisms controlling plant pathogens

    NARCIS (Netherlands)

    Köhl, J.

    2010-01-01

    The invention relates to control of pathogen caused diseases on leaves, fruits and ears in plants, such as apple scab (Venturia inaequalis by treatment of plant with an isolate of Cladosporium cladosporioides. The treatment is effective in both prevention and treatment of the fungal infection

  11. Ewingella Americana: An Emerging True Pathogen

    Directory of Open Access Journals (Sweden)

    Syed Hassan

    2012-01-01

    Full Text Available Infections caused by Ewingella americana have been rarely reported in the literature. Most of the cases that have been reported were among the immunocompromised patients. We report a case of E. americana causing osteomyelitis and septic arthritis of the shoulder joint in a previous intravenous drug abuser. The causative pathogen was identified by synovial fluid analysis and culture.

  12. Isolation of pathogen-containing vacuoles.

    Science.gov (United States)

    Shevchuk, Olga; Steinert, Michael

    2013-01-01

    Dictyostelium discoideum cells are "professional phagocytes," as they ingest a large variety of bacteria, yeast, and inert particles. Several bacterial pathogens are able to survive intracellularly within specialized vacuoles of D. discoideum by interfering with host signaling pathways. To better understand the molecular mechanisms underlying these evolutionary conserved processes we have established a method for the isolation of pathogen-containing vacuoles (PCVs). The isolation protocol describes the infection of D. discoideum cells with the intracellular pathogen Legionella pneumophila, loading of the lysosomal compartment with colloidal iron, mechanical lysis of host cells, iodophenylnitrophenyltetrazolium (INT) heavy labeling of mitochondria, removal of nucleic acid by Benzonase treatment, separation of nuclei by low-speed centrifugation, and the magnetic removal of lysosomes. The subcellular fractionation in a discontinuous sucrose density OptiPrep gradient allows the separation of mitochondria and to prepare PCVs with high purity. The proteins isolated from PCVs have been successfully subjected to mass spectrometry and allowed to analyze pathogen-directed maturation processes of vacuoles. The method can also be applied for subsequent protein modification analyses and lipidome comparisons.

  13. Pathogenicity of Trypanosoma congolense infection following oral ...

    African Journals Online (AJOL)

    Eighty healthy adult albino rats of both sexes weighing 180-200g were used in two experiments to study the effects of oral calcium chloride treatment on the pathogenicity of Trypanosoma congolense infection. Experiment 1 was terminated at the peak of parasitaemia while experiment II was allowed to run a full course.

  14. Carp erythrodermatitis : host defense-pathogen interaction

    NARCIS (Netherlands)

    Pourreau, C.N.

    1990-01-01

    The outcome of a bacterial infection depends on the interaction between pathogen and host. The ability of the microbe to survive in the host depends on its invasive potential (i.e. spreading and multiplication), and its ability to obtain essential nutrients and to resist the

  15. Control of indigenous pathogenic bacteria in seafood

    DEFF Research Database (Denmark)

    Huss, Hans Henrik

    1997-01-01

    The pathogenic bacteria indigenous to the aquatic and general environment are listed. Their distribution in nature, prevalence in seafood and the possibilities for growth of these organisms in various types of products are outlined These data, combined with what is known regarding the epidemiology...

  16. Plant Fungal Pathogens: Methods and Protocols

    NARCIS (Netherlands)

    Bolton, M.D.; Thomma, B.P.H.J.

    2012-01-01

    Over the course of evolution, fungi have adapted to occupy specific niches, from symbiotically inhabiting the flora of the intestinal tract of mammals to saprophytic growth on leaf litter resting on the forest floor. In Plant Fungal Pathogens: Methods and Protocols, expert researchers in the field

  17. Low-Incidence, High-Consequence Pathogens

    Centers for Disease Control (CDC) Podcasts

    2014-02-21

    Dr. Stephan Monroe, a deputy director at CDC, discusses the impact of low-incidence, high-consequence pathogens globally.  Created: 2/21/2014 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/26/2014.

  18. Incidence of indicator organisms, opportunistic and pathogenic ...

    African Journals Online (AJOL)

    Tilapia from the supermarkets and tilapia and catfish from street vendors were analyzed for the microbial load, presence of indicator microorganisms, opportunistic and pathogenic bacteria using conventional microbiological methods. Though coliforms were found in 84% of fish from the street vendors, only 16% of the fish ...

  19. Quantitative multiplex detection of pathogen biomarkers

    Science.gov (United States)

    Mukundan, Harshini; Xie, Hongzhi; Swanson, Basil I; Martinez, Jennifer; Grace, Wynne K

    2014-10-14

    The present invention addresses the simultaneous detection and quantitative measurement of multiple biomolecules, e.g., pathogen biomarkers through either a sandwich assay approach or a lipid insertion approach. The invention can further employ a multichannel, structure with multi-sensor elements per channel.

  20. Cultural, morphological, pathogenic and molecular characterization ...

    African Journals Online (AJOL)

    Alternaria blotch (Alternaria mali) causes severe foliar damage to apple trees in Kashmir. Twenty one (21) isolates of A. mali were collected from different locations and characterized for cultural, morphological, pathogenic and molecular variations. A. mali colonies varied in their cultural behaviour ranging from velvety to ...

  1. Home Air Purifiers Eradicate Harmful Pathogens

    Science.gov (United States)

    2014-01-01

    Marshall Space Flight Center funded the University of Madison-Wisconsin to develop ethylene scrubbers to keep produce fresh in space. Akida Holdings of Jacksonville, Florida, licensed the technology and developed Airocide, an air purifier that can kill airborne pathogens. Previously designed for industrial spaces, there is now a specially designed unit for home use.

  2. Incidence of Bacterial Pathogens following Biomechanical ...

    African Journals Online (AJOL)

    A correlation exists between endodontic microflora in pulpal disease and endodontic treatment failure. This study presents data on the recoverable bacterial pathogens following biomechanical treatment of infected root canals. Standard endodontic procedure were used to access tooth pulp cavity, processed and fluid ...

  3. EPCOT, NASA and plant pathogens in space.

    Science.gov (United States)

    White, R

    1996-01-01

    Cooperative work between NASA and Walt Disney World's EPCOT Land Pavilion is described. Joint efforts include research about allelopathy in multi-species plant cropping in CELSS, LEDs as light sources in hydroponic systems, and the growth of plant pathogens in space.

  4. Use of Bacteriophages to control bacterial pathogens

    Science.gov (United States)

    Lytic bacteriophages can provide a natural method and an effective alternative to antibiotics to reduce bacterial pathogens in animals, foods, and other environments. Bacteriophages (phages) are viruses which infect bacterial cells and eventually kill them through lysis, and represent the most abun...

  5. PATHOGENIC POTENTIALS OF ESCHERICHIA COLI ISOLATED ...

    African Journals Online (AJOL)

    Electrolyte and haematological parameters in rabbits infected with pathogenic isolates of Escherichia coli from rural water supplies in Rivers State, Nigeria, where monitored. Rabbits were orally infected with suspension containing 3x107 cfu /ml of Escherichia coli to induce diarrhoea, and the electrolyte (sodium, potassium ...

  6. RNAi suppressors encoded by pathogenic human viruses

    NARCIS (Netherlands)

    de Vries, Walter; Berkhout, Ben

    2008-01-01

    RNA silencing or RNAi interference (RNAi) serves as an innate antiviral mechanism in plants, fungi and animals. Human viruses, like plant viruses, encode suppressor proteins or RNAs that block or modulate the RNAi pathway. This review summarizes the mechanisms by which pathogenic human viruses

  7. Multivalent glycoconjugates as anti-pathogenic agents

    NARCIS (Netherlands)

    Bernardi, J.; Jiménez-Barbero, J.; Casnati, A.; Castro, C.; Darbre, T.; Fieschi, F.; Finne, J.; Funken, H.; Jaeger, K.E.; Lahmann, M.; Lindhorst, T.K.; Marradi, M.; Messner, P.; Molinaro, A.; Murphy, P.V.; Nativi, C.; Oscarson, S.; Penadés, S.; Peri, F.; Pieters, R.J.; Renaudet, O.; Reymond, J.L.; Richichi, B.; Rojo, J.; Sansone, F.; Schäffer, C.; Turnbull, W.B.; Velasco-Torrijos, T.; Vidal, S.; Vincent, S.; Wennekes, T.; Zuilhof, H.; Imberty, A.

    2013-01-01

    Multivalency plays a major role in biological processes and particularly in the relationship between pathogenic microorganisms and their host that involves protein-glycan recognition. These interactions occur during the first steps of infection, for specific recognition between host and bacteria,

  8. Insect Pathogenic Fungi as Endophytes.

    Science.gov (United States)

    Moonjely, S; Barelli, L; Bidochka, M J

    2016-01-01

    In this chapter, we explore some of the evolutionary, ecological, molecular genetics, and applied aspects of a subset of insect pathogenic fungi that also have a lifestyle as endophytes and we term endophytic insect pathogenic fungi (EIPF). We focus particularly on Metarhizium spp. and Beauveria bassiana as EIPF. The discussion of the evolution of EIPF challenges a view that these fungi were first and foremost insect pathogens that eventually evolved to colonize plants. Phylogenetic evidence shows that the lineages of EIPF are most closely related to grass endophytes that diverged c. 100MYA. We discuss the relationship between genes involved in "insect pathogenesis" and those involved in "endophytism" and provide examples of genes with potential importance in lifestyle transitions toward insect pathogenicity. That is, some genes for insect pathogenesis may have been coopted from genes involved in endophytic colonization. Other genes may be multifunctional and serve in both lifestyle capacities. The interactions of EIPF with their host plants are discussed in some detail. The genetic basis for rhizospheric competence, plant communication, and nutrient exchange is examined and we highlight, with examples, the benefits of EIPF to plants, and the potential reservoir of secondary metabolites hidden within these beneficial symbioses. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Paleogene radiation of a plant pathogenic mushroom.

    Directory of Open Access Journals (Sweden)

    Martin P A Coetzee

    Full Text Available The global movement and speciation of fungal plant pathogens is important, especially because of the economic losses they cause and the ease with which they are able to spread across large areas. Understanding the biogeography and origin of these plant pathogens can provide insights regarding their dispersal and current day distribution. We tested the hypothesis of a Gondwanan origin of the plant pathogenic mushroom genus Armillaria and the currently accepted premise that vicariance accounts for the extant distribution of the species.The phylogeny of a selection of Armillaria species was reconstructed based on Maximum Parsimony (MP, Maximum Likelihood (ML and Bayesian Inference (BI. A timeline was then placed on the divergence of lineages using a Bayesian relaxed molecular clock approach.Phylogenetic analyses of sequenced data for three combined nuclear regions provided strong support for three major geographically defined clades: Holarctic, South American-Australasian and African. Molecular dating placed the initial radiation of the genus at 54 million years ago within the Early Paleogene, postdating the tectonic break-up of Gondwana.The distribution of extant Armillaria species is the result of ancient long-distance dispersal rather than vicariance due to continental drift. As these finding are contrary to most prior vicariance hypotheses for fungi, our results highlight the important role of long-distance dispersal in the radiation of fungal pathogens from the Southern Hemisphere.

  10. Plastic Transcriptomes Stabilize Immunity to Pathogen Diversity

    DEFF Research Database (Denmark)

    Zhang, Wei; Corwin, Jason A; Copeland, Daniel

    2017-01-01

    To respond to pathogen attack, selection and associated evolution has led to the creation of plant immune system that are a highly effective and inducible defense system. Central to this system are the plant defense hormones jasmonic acid (JA) and salicylic acid (SA) and crosstalk between the two...

  11. Rapid methods: the detection of foodborne pathogens

    NARCIS (Netherlands)

    Beumer, R.R.; Hazeleger, W.C.

    2009-01-01

    Although bacteria are the first type of microorganisms that come to mind when discussing microbial food safety, they are by no means the only pathogenic foodborne microorganisms. Mycotoxin producing moulds, human enteric viruses, protozoan parasites and marine biotoxins are also of importance.

  12. Tracking Zoonotic Pathogens in Dairy Production Chains

    Science.gov (United States)

    Dairy farming is a highly productive system producing ample amounts of high-quality milk and meat from fewer cows on less land on fewer, but larger, farms. Despite this consolidation and modernization zoonotic pathogenic bacteria and protozoans remain problems on the modern dairy farm. Although past...

  13. teaching hospital: common bacterial pathogens seen.

    African Journals Online (AJOL)

    pathogens in pyogenic meningitis. Most of the delivery occurred outside the teaching hospital, even those that delivered in the hospital, some come in during labour. ' _ Conclusion: Neonatal bacterial infections are still a cause of high morbidity and mortality of the newborn in our setting. To reduce the morbidity and mortality ...

  14. 77 FR 34783 - Highly Pathogenic Avian Influenza

    Science.gov (United States)

    2012-06-12

    ... Avian Influenza AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION: Interim rule... importation of bird and poultry products from regions where any subtype of highly pathogenic avian influenza... avian influenza (HPAI). On January 24, 2011, we published in the Federal Register (76 FR 4046-4056...

  15. Occurrences of pathogenic Vibrio parahaemolyticus from Vellar ...

    African Journals Online (AJOL)

    Vibrio parahaemolyticus is the predominant seafood pathogen associated with human gastroenteritis. Samples were collected from Vellar estuary, shrimp ponds and shrimp for characterization of V. parahaemolyticus. A total of 26 blue green centre (BG) Vibrio strains were isolated and characterized through biochemical ...

  16. Antimicrobial susceptibilty of potentially pathogenic halophilic Vibrio ...

    African Journals Online (AJOL)

    Surveillance of antimicrobial resistance is indispensable for empirical treatment of infections and in preventing the spread of antimicrobial resistant microorganisms. This study is aimed at determining the antibiotic susceptibility of potentially pathogenic halophylic Vibrio species isolated in Lagos, Nigeria. Susceptibility ...

  17. The Role of Pathogenic Autoantibodies in Autoimmunity

    Directory of Open Access Journals (Sweden)

    Merrill J. Rowley

    2015-11-01

    Full Text Available The serological presence of autoantibodies is diagnostic of autoimmunity, and these autoantibodies may be present for many years before the presentation of autoimmune disease (AID. Although a pathogenic role has been demonstrated for various autoantibodies reactive with cell surface and extracellular autoantigens, studies using monoclonal antibodies (mAb show not all antibodies in the polyclonal response are pathogenic. Differences depend on Fab-mediated diversity in epitope specificity, Fc-mediated effects based on immunoglobulin (Ig class and subclass, activation of complement, and the milieu in which the reaction occurs. These autoantibodies often occur in organ-specific AID and this review illustrates their pathogenic and highly specific effects. The role of autoantibodies associated with intracellular antigens is less clear. In vitro they may inhibit or adversely affect well-defined intracellular biochemical pathways, yet, in vivo they are separated from their autoantigens by multiple cellular barriers. Recent evidence that Ig can traverse cell membranes, interact with intracellular proteins, and induce apoptosis has provided new evidence for a pathogenic role for such autoantibodies. An understanding of how autoantibodies behave in the polyclonal response and their role in pathogenesis of AID may help identify populations of culprit B-cells and selection of treatments that suppress or eliminate them.

  18. Pathogenic Responses of Cowpea ( Vigna unguiculata ) Inoculated ...

    African Journals Online (AJOL)

    A study was carried out using potted plants arranged in a randomized complete block experimental design, to evaluate the pathogenic responses of Cowpea that was inoculated with cucumber mosaic virus to soil amendment with neem leaf powder. The amendments were applied at varying rates of 0.125Kg/10kg soil, ...

  19. Host-pathogen interactions in typhoid fever

    NARCIS (Netherlands)

    de Jong, H.K.

    2015-01-01

    This thesis focuses on host-pathogen interactions in Salmonella Typhi and Burkholderia pseudomallei infections and explores the interplay between these bacteria and the innate immune system. Typhoid fever is one of the most common causes of bacterial infection in low-income countries. With adequate

  20. Suppression of soil-borne plant pathogens

    NARCIS (Netherlands)

    Agtmaal, van M.

    2015-01-01

    Soil borne plant pathogens considerably reduce crop yields worldwide and are difficult to control due to their ”masked” occurrence  in the heterogeneous soil environment. This hampers the efficacy of chemical - and microbiological control agents.   Outbreaks of crop

  1. Morphological, cultural, pathogenic and molecular variability ...

    African Journals Online (AJOL)

    Alternaria blight (Alternaria brassicae) causes severe foliar damage to Indian mustard in Uttarakhand. Ten (10) isolates of A. brassicae were collected from different hosts and characterized for cultural, morphological, pathogenic and molecular variations. A. brassicae colonies varied in their cultural behaviour ranging from ...

  2. Genetic characterization of mango anthracnose pathogen ...

    African Journals Online (AJOL)

    USER

    2010-06-28

    Jun 28, 2010 ... from different agroclimatic zones of India. The isolates were evaluated for their pathogenic variability on mango seedlings and genetic characterization using random amplified polymorphic DNA (RAPD molecular techniques). The random primers OPA-1, 3, 5, 9, 11, 15, 16 and 18 were used and the twenty-.

  3. Exploiting Quorum Sensing To Confuse Bacterial Pathogens

    Science.gov (United States)

    LaSarre, Breah

    2013-01-01

    SUMMARY Cell-cell communication, or quorum sensing, is a widespread phenomenon in bacteria that is used to coordinate gene expression among local populations. Its use by bacterial pathogens to regulate genes that promote invasion, defense, and spread has been particularly well documented. With the ongoing emergence of antibiotic-resistant pathogens, there is a current need for development of alternative therapeutic strategies. An antivirulence approach by which quorum sensing is impeded has caught on as a viable means to manipulate bacterial processes, especially pathogenic traits that are harmful to human and animal health and agricultural productivity. The identification and development of chemical compounds and enzymes that facilitate quorum-sensing inhibition (QSI) by targeting signaling molecules, signal biogenesis, or signal detection are reviewed here. Overall, the evidence suggests that QSI therapy may be efficacious against some, but not necessarily all, bacterial pathogens, and several failures and ongoing concerns that may steer future studies in productive directions are discussed. Nevertheless, various QSI successes have rightfully perpetuated excitement surrounding new potential therapies, and this review highlights promising QSI leads in disrupting pathogenesis in both plants and animals. PMID:23471618

  4. Antibiotic resistance and pathogenicity factors in Staphylococcus ...

    Indian Academy of Sciences (India)

    Methicillin-resistant Staphylococcus aureus (MRSA) poses a serious problem in dairy animals suffering from mastitis. In the present study, the distribution of mastitic MRSA and antibiotic resistance was studied in 107 strains of. S. aureus isolated from milk samples from 195 infected udders. The characterizations pathogenic ...

  5. Microbial minimalism: genome reduction in bacterial pathogens.

    Science.gov (United States)

    Moran, Nancy A

    2002-03-08

    When bacterial lineages make the transition from free-living or facultatively parasitic life cycles to permanent associations with hosts, they undergo a major loss of genes and DNA. Complete genome sequences are providing an understanding of how extreme genome reduction affects evolutionary directions and metabolic capabilities of obligate pathogens and symbionts.

  6. CASE REPORT Uncommon Pathogen Bacillus Cereus Causing ...

    African Journals Online (AJOL)

    2018-01-01

    Jan 1, 2018 ... Uncommon Pathogen Bacillus Cereus Causing Subdural Empyema in a Child. Prastiya Indra Gunawan1*, Leny Kartina1, Dwiyanti Puspitasari1, Erny Erny2. OPEN ACCESS ... secondary to middle ear infection, meningitis, brain surgery, ... classic clinical syndrome is an acute febrile illness punctuated by.

  7. Antibiotic susceptibility profiles of oral pathogens

    NARCIS (Netherlands)

    Veloo, A. C. M.; Seme, K.; Raangs, Gerwin; Rurenga, P.; Singadji, Z.; Wekema - Mulder, G.; van Winkelhoff, A. J.

    2012-01-01

    Periodontitis is a bacterial disease that can be treated with systemic antibiotics. The aim of this study was to establish the antibiotic susceptibility profiles of five periodontal pathogens to six commonly used antibiotics in periodontics. A total of 247 periodontal bacterial isolates were tested

  8. Langerhans cells in innate defense against pathogens

    NARCIS (Netherlands)

    de Jong, Marein A. W. P.; Geijtenbeek, Teunis B. H.

    2010-01-01

    Langerhans cells (LCs) are at the frontline in defense against mucosal infections because they line the mucosal tissues and are ideally situated to intercept pathogens. Recent data suggest that LCs have an innate anti-HIV-1 function. LCs express the LC-specific C-type lectin Langerin that

  9. Pathogen Pressure Puts Immune Defense into Perspective

    NARCIS (Netherlands)

    Horrocks, Nicholas P. C.; Matson, Kevin D.; Tieleman, B. Irene

    2011-01-01

    The extent to which organisms can protect themselves from disease depends on both the immune defenses they maintain and the pathogens they face. At the same time, immune systems are shaped by the antigens they encounter, both over ecological and evolutionary time. Ecological immunologists often

  10. Pathogen pressure puts immune defense into perspective

    NARCIS (Netherlands)

    Horrocks, N.P.C.; Matson, K.D.; Tieleman, B.I.

    2011-01-01

    The extent to which organisms can protect themselves from disease depends on both the immune defenses they maintain and the pathogens they face. At the same time, immune systems are shaped by the antigens they encounter, both over ecological and evolutionary time. Ecological immunologists often

  11. Antibiotic resistance and pathogenicity factors in Staphylococcus ...

    Indian Academy of Sciences (India)

    Methicillin-resistant Staphylococcus aureus (MRSA) poses a serious problem in dairy animals suffering from mastitis. In the present study, the distribution of mastitic MRSA and antibiotic resistance was studied in 107 strains of S. aureus isolated from milk samples from 195 infected udders. The characterizations pathogenic ...

  12. The quantitative basis of the Arabidopsis innate immune system to endemic pathogens depends on pathogen genetics

    DEFF Research Database (Denmark)

    Corwin, Jason A; Copeland, Daniel; Feusier, Julie

    2016-01-01

    The most established model of the eukaryotic innate immune system is derived from examples of large effect monogenic quantitative resistance to pathogens. However, many host-pathogen interactions involve many genes of small to medium effect and exhibit quantitative resistance. We used...... the Arabidopsis-Botrytis pathosystem to explore the quantitative genetic architecture underlying host innate immune system in a population of Arabidopsis thaliana. By infecting a diverse panel of Arabidopsis accessions with four phenotypically and genotypically distinct isolates of the fungal necrotroph B...... shows that the genetic architecture underlying host innate immune system is extremely complex and is likely able to sense and respond to differential virulence among pathogen genotypes....

  13. The sunflower downy mildew pathogen Plasmopara halstedii.

    Science.gov (United States)

    Gascuel, Quentin; Martinez, Yves; Boniface, Marie-Claude; Vear, Felicity; Pichon, Magalie; Godiard, Laurence

    2015-02-01

    Downy mildew of sunflower is caused by Plasmopara halstedii (Farlow) Berlese & de Toni. Plasmopara halstedii is an obligate biotrophic oomycete pathogen that attacks annual Helianthus species and cultivated sunflower, Helianthus annuus. Depending on the sunflower developmental stage at which infection occurs, the characteristic symptoms range from young seedling death, plant dwarfing, leaf bleaching and sporulation to the production of infertile flowers. Downy mildew attacks can have a great economic impact on sunflower crops, and several Pl resistance genes are present in cultivars to protect them against the disease. Nevertheless, some of these resistances have been overcome by the occurrence of novel isolates of the pathogen showing increased virulence. A better characterization of P. halstedii infection and dissemination mechanisms, and the identification of the molecular basis of the interaction with sunflower, is a prerequisite to efficiently fight this pathogen. This review summarizes what is currently known about P. halstedii, provides new insights into its infection cycle on resistant and susceptible sunflower lines using scanning electron and light microscopy imaging, and sheds light on the pathogenicity factors of P. halstedii obtained from recent molecular data. Kingdom Stramenopila; Phylum Oomycota; Class Oomycetes; Order Peronosporales; Family Peronosporaceae; Genus Plasmopara; Species Plasmopara halstedii. Sunflower seedling damping off, dwarfing of the plant, bleaching of leaves, starting from veins, and visible white sporulation, initially on the lower side of cotyledons and leaves. Plasmopara halstedii infection may severely impact sunflower seed yield. In spring, germination of overwintered sexual oospores leads to sunflower root infection. Intercellular hyphae are responsible for systemic plant colonization and the induction of disease symptoms. Under humid and fresh conditions, dissemination structures are produced by the pathogen on all

  14. Bacteriophages for detection of bacterial pathogens

    International Nuclear Information System (INIS)

    Kutateladze, M.

    2009-01-01

    The G. Eliava Institute of Bacteriophages, Microbiology and Virology (Tbilisi, Georgia) is one of the most famous institutions focused on bacteriophage research for the elaboration of appropriate phage methodologies for human and animal protection. The main direction of the institute is the study and production of bacteriophages against intestinal disorders (dysentery, typhoid, intesti) and purulent-septic infections (staphylococcus, streptococcus, pyophage, etc.). These preparations were successfully introduced during the Soviet era, and for decades were used throughout the former Soviet Union and in other Socialist countries for the treatment, prophylaxis, and diagnosis of various infectious diseases, including those caused by antibiotic-resistant bacterial strains. Bacteriophages were widely used for identifying and detecting infections caused by the most dangerous pathogens and causative agents of epidemiological outbreaks. The specific topic of this presentation is the phage typing of bacterial species, which can be an important method for epidemiological diagnostics. Together with different genetic methodologies - such as PCR-based methods, PFGE, plasmid fingerprinting, and ribosomal typing - phage typing is one method for identifying bacterial pathogens. The method has a high percentage of determination of phage types, high specificity of reaction, and is easy for interpretation and use by health workers. Phage typing was applied for inter-species differentiation of different species of Salmonella, S. typhi, Brucella spp, Staphylococcus aureus, E. col,i Clostridium deficile, Vibrio cholerae, Yersinia pestis, Yersinia enterocolitica, Lysteria monocytogenes, Clostridium perfringens, Clostridium tetani, plant pathogens, and other bacterial pathogens. In addition to addressing the utility and efficacy of phage typing, the paper will discuss the isolation and selection of diagnostic typing phages for interspecies differentiation of pathogens that is necessary

  15. Overexpression of Differentially Expressed Genes Identified in Non-pathogenic and Pathogenic Entamoeba histolytica Clones Allow Identification of New Pathogenicity Factors Involved in Amoebic Liver Abscess Formation.

    Directory of Open Access Journals (Sweden)

    Martin Meyer

    2016-08-01

    Full Text Available We here compared pathogenic (p and non-pathogenic (np isolates of Entamoeba histolytica to identify molecules involved in the ability of this parasite to induce amoebic liver abscess (ALA-like lesions in two rodent models for the disease. We performed a comprehensive analysis of 12 clones (A1-A12 derived from a non-pathogenic isolate HM-1:IMSS-A and 12 clones (B1-B12 derived from a pathogenic isolate HM-1:IMSS-B. "Non-pathogenicity" included the induction of small and quickly resolved lesions while "pathogenicity" comprised larger abscess development that overstayed day 7 post infection. All A-clones were designated as non-pathogenic, whereas 4 out of 12 B-clones lost their ability to induce ALAs in gerbils. No correlation between ALA formation and cysteine peptidase (CP activity, haemolytic activity, erythrophagocytosis, motility or cytopathic activity was found. To identify the molecular framework underlying different pathogenic phenotypes, three clones were selected for in-depth transcriptome analyses. Comparison of a non-pathogenic clone A1np with pathogenic clone B2p revealed 76 differentially expressed genes, whereas comparison of a non-pathogenic clone B8np with B2p revealed only 19 differentially expressed genes. Only six genes were found to be similarly regulated in the two non-pathogenic clones A1np and B8np in comparison with the pathogenic clone B2p. Based on these analyses, we chose 20 candidate genes and evaluated their roles in ALA formation using the respective gene-overexpressing transfectants. We conclude that different mechanisms lead to loss of pathogenicity. In total, we identified eight proteins, comprising a metallopeptidase, C2 domain proteins, alcohol dehydrogenases and hypothetical proteins, that affect the pathogenicity of E. histolytica.

  16. Overexpression of Differentially Expressed Genes Identified in Non-pathogenic and Pathogenic Entamoeba histolytica Clones Allow Identification of New Pathogenicity Factors Involved in Amoebic Liver Abscess Formation.

    Science.gov (United States)

    Meyer, Martin; Fehling, Helena; Matthiesen, Jenny; Lorenzen, Stephan; Schuldt, Kathrin; Bernin, Hannah; Zaruba, Mareen; Lender, Corinna; Ernst, Thomas; Ittrich, Harald; Roeder, Thomas; Tannich, Egbert; Lotter, Hannelore; Bruchhaus, Iris

    2016-08-01

    We here compared pathogenic (p) and non-pathogenic (np) isolates of Entamoeba histolytica to identify molecules involved in the ability of this parasite to induce amoebic liver abscess (ALA)-like lesions in two rodent models for the disease. We performed a comprehensive analysis of 12 clones (A1-A12) derived from a non-pathogenic isolate HM-1:IMSS-A and 12 clones (B1-B12) derived from a pathogenic isolate HM-1:IMSS-B. "Non-pathogenicity" included the induction of small and quickly resolved lesions while "pathogenicity" comprised larger abscess development that overstayed day 7 post infection. All A-clones were designated as non-pathogenic, whereas 4 out of 12 B-clones lost their ability to induce ALAs in gerbils. No correlation between ALA formation and cysteine peptidase (CP) activity, haemolytic activity, erythrophagocytosis, motility or cytopathic activity was found. To identify the molecular framework underlying different pathogenic phenotypes, three clones were selected for in-depth transcriptome analyses. Comparison of a non-pathogenic clone A1np with pathogenic clone B2p revealed 76 differentially expressed genes, whereas comparison of a non-pathogenic clone B8np with B2p revealed only 19 differentially expressed genes. Only six genes were found to be similarly regulated in the two non-pathogenic clones A1np and B8np in comparison with the pathogenic clone B2p. Based on these analyses, we chose 20 candidate genes and evaluated their roles in ALA formation using the respective gene-overexpressing transfectants. We conclude that different mechanisms lead to loss of pathogenicity. In total, we identified eight proteins, comprising a metallopeptidase, C2 domain proteins, alcohol dehydrogenases and hypothetical proteins, that affect the pathogenicity of E. histolytica.

  17. Recent developments in pathogen detection arrays: implications for fungal plant pathogens and use in practica

    NARCIS (Netherlands)

    Lievens, B.; Thomma, B.P.H.J.

    2005-01-01

    The failure to adequately identify plant pathogens from culture-based morphological techniques has led to the development of culture-independent molecular approaches. Increasingly, diagnostic laboratories are pursuing fast routine methods that provide reliable identification, sensitive detection,

  18. Dynamics of delayed pathogen infection models with pathogenic and cellular infections and immune impairment

    Science.gov (United States)

    Elaiw, A. M.; Raezah, A. A.; Alofi, B. S.

    2018-02-01

    We study the global dynamics of delayed pathogen infection models with immune impairment. Both pathogen-to-susceptible and infected-to-susceptible transmissions have been considered. Bilinear and saturated incidence rates are considered in the first and second model, respectively. We drive the basic reproduction parameter R0 which determines the global dynamics of models. Using Lyapunov method, we established the global stability of the models' steady states. The theoretical results are confirmed by numerical simulations.

  19. Antisense transcription regulates the expression of the enterohemorrhagic Escherichia coli virulence regulatory gene ler in response to the intracellular iron concentration.

    Directory of Open Access Journals (Sweden)

    Toru Tobe

    Full Text Available Enteric pathogens, such as enterohemorrhagic E. coli (EHEC O157:H7, encounter varying concentrations of iron during their life cycle. In the gastrointestinal tract, the amount of available free iron is limited because of absorption by host factors. EHEC and other enteric pathogens have developed sophisticated iron-responsive systems to utilize limited iron resources, and these systems are primarily regulated by the Fur repressor protein. The iron concentration could be a signal that controls gene expression in the intestines. In this study, we explored the role of iron in LEE (locus for enterocyte effacement virulence gene expression in EHEC. In contrast to the expression of Fur-regulated genes, the expression of LEE genes was greatly reduced in fur mutants irrespective of the iron concentration. The expression of the ler gene, the LEE-encoded master regulator, was affected at a post-transcription step by fur mutation. Further analysis showed that the loss of Fur affected the translation of the ler gene by increasing the intracellular concentration of free iron, and the transcription of the antisense strand was necessary for regulation. The results indicate that LEE gene expression is closely linked to the control of intracellular free iron homeostasis.

  20. A secretome view of colonisation factors in Shiga toxin-encoding Escherichia coli (STEC): from enterohaemorrhagic E. coli (EHEC) to related enteropathotypes.

    Science.gov (United States)

    Monteiro, Ricardo; Ageorges, Valentin; Rojas-Lopez, Maricarmen; Schmidt, Herbert; Weiss, Agnes; Bertin, Yolande; Forano, Evelyne; Jubelin, Grégory; Henderson, Ian R; Livrelli, Valérie; Gobert, Alain P; Rosini, Roberto; Soriani, Marco; Desvaux, Mickaël

    2016-08-01

    Shiga toxin-encoding Escherichia coli (STEC) regroup strains that carry genes encoding Shiga toxin (Stx). Among intestinal pathogenic E. coli, enterohaemorrhagic E. coli (EHEC) constitute the major subgroup of virulent STEC. EHEC cause serious human disease such as haemorrhagic colitis and haemolytic-uremic syndrome. While EHEC have evolved from enteropathogenic E. coli, hybrids with enteroaggregative E. coli have recently emerged. Of note, some enteroinvasive E. coli also belong to the STEC group. While the LEE (locus of enterocyte effacement) is a key and prominent molecular determinant in the pathogenicity, neither all EHEC nor STEC contain the LEE, suggesting that they possess additional virulence and colonisation factors. Currently, nine protein secretion systems have been described in diderm-lipopolysaccharide bacteria (archetypal Gram-negative) and can be involved in the secretion of extracellular effectors, cell-surface proteins or assembly of cell-surface organelles, such as flagella or pili. In this review, we focus on the secretome of STEC and related enteropathotypes, which are relevant to the colonisation of biotic and abiotic surfaces. Considering the wealth of potential protein trafficking mechanisms, the different combinations of colonisation factors and modulation of their expression is further emphasised with regard to the ecophysiology of STEC. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. AquaPathogen X--A template database for tracking field isolates of aquatic pathogens

    Science.gov (United States)

    Emmenegger, Evi; Kurath, Gael

    2012-01-01

    AquaPathogen X is a template database for recording information on individual isolates of aquatic pathogens and is available for download from the U.S. Geological Survey (USGS) Western Fisheries Research Center (WFRC) website (http://wfrc.usgs.gov). This template database can accommodate the nucleotide sequence data generated in molecular epidemiological studies along with the myriad of abiotic and biotic traits associated with isolates of various pathogens (for example, viruses, parasites, or bacteria) from multiple aquatic animal host species (for example, fish, shellfish, or shrimp). The simultaneous cataloging of isolates from different aquatic pathogens is a unique feature to the AquaPathogen X database, which can be used in surveillance of emerging aquatic animal diseases and clarification of main risk factors associated with pathogen incursions into new water systems. As a template database, the data fields are empty upon download and can be modified to user specifications. For example, an application of the template database that stores the epidemiological profiles of fish virus isolates, called Fish ViroTrak (fig. 1), was also developed (Emmenegger and others, 2011).

  2. Efficacy of Miswak on Oral Pathogens

    Directory of Open Access Journals (Sweden)

    Adnan Sukkarwalla

    2013-01-01

    Full Text Available The oral cavity harbors a diverse and abundant number of complex oral pathogens causing different oral diseases. The development of dental caries and periodontal diseases has been found to be closely associated with various gram positive and gram negative microrganisms. Miswak, a natural toothbrush, has been documented as a potent antibacterial aid and its use is encouraged in different countries because of its good taste, texture, availability, cost and beneficial effect on teeth and supporting tissues. Different researches have been carried out to evaluate the antimicrobial effects of Miswak. This review encompasses the efficacy of Miswak on suppression of oral pathogens with respect to conducted on fungi as well as cariogenic, periodontal and endodontic bacteria.

  3. Bacteriophage interactions with marine pathogenic Vibrios

    DEFF Research Database (Denmark)

    Kalatzis, Panagiotis

    Incidents of Vibrio-associated diseases in marine aquaculture are increasingly reported on a global scale, incited also by the world’s rising temperature. Administration of antibiotics has been the most commonly applied remedy used for facing vibriosis outbreaks, giving rise to concerns about...... pathogens. The combinatory administration of virulent bacteriophages φSt2 and φGrn1, isolated against Vibrio alginolyticus significantly reduced the Vibrio load in cultures of Artemia salina live prey, decreasing subsequently the risk of a vibriosis outbreak in the marine hatchery. During infection...... to studying the interactions between marine pathogenic Vibrio and their corresponding bacteriophages, while discussing the potential and limitations of phage therapy application in the biological control of vibriosis....

  4. Bacteriophages in the control of pathogenic vibrios

    Directory of Open Access Journals (Sweden)

    Nicolás Plaza

    2018-01-01

    Full Text Available Vibrios are common inhabitants of marine and estuarine environments. Some of them can be pathogenic to humans and/or marine animals using a broad repertory of virulence factors. Lately, several reports have indicated that the incidence of Vibrio infections in humans is rising and also in animals constitute a continuing threat for aquaculture. Moreover, the continuous use of antibiotics has been accompanied by an emergence of antibiotic resistance in Vibrio species, implying a necessity for efficient treatments. One promising alternative that emerges is the use of lytic bacteriophages; however, there are some drawbacks that should be overcome to make phage therapy a widely accepted method. In this work, we discuss about the major pathogenic Vibrio species and the progress, benefits and disadvantages that have been detected during the experimental use of bacteriophages to their control.

  5. Common Features of Opportunistic Premise Plumbing Pathogens

    Directory of Open Access Journals (Sweden)

    Joseph O. Falkinham

    2015-04-01

    Full Text Available Recently it has been estimated that the annual cost of diseases caused by the waterborne pathogens Legionella pneumonia, Mycobacterium avium, and Pseudomonas aeruginosa is $500 million. For the period 2001–2012, the estimated cost of hospital admissions for nontuberculous mycobacterial pulmonary disease, the majority caused by M. avium, was almost $1 billion. These three waterborne opportunistic pathogens are normal inhabitants of drinking water—not contaminants—that share a number of key characteristics that predispose them to survival, persistence, and growth in drinking water distribution systems and premise plumbing. Herein, I list and describe these shared characteristics that include: disinfectant-resistance, biofilm-formation, growth in amoebae, growth at low organic carbon concentrations (oligotrophic, and growth under conditions of stagnation. This review is intended to increase awareness of OPPPs, identify emerging OPPPs, and challenge the drinking water industry to develop novel approaches toward their control.

  6. Formaldehyde stress responses in bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Nathan Houqian Chen

    2016-03-01

    Full Text Available Formaldehyde is the simplest of all aldehydes and is highly cytotoxic. Its use and associated dangers from environmental exposure have been well documented. Detoxification systems for formaldehyde are found throughout the biological world and they are especially important in methylotrophic bacteria, which generate this compound as part of their metabolism of methanol. Formaldehyde metabolizing systems can be divided into those dependent upon pterin cofactors, sugar phosphates and those dependent upon glutathione. The more prevalent thiol-dependent formaldehyde detoxification system is found in many bacterial pathogens, almost all of which do not metabolize methane or methanol. This review describes the endogenous and exogenous sources of formaldehyde, its toxic effects and mechanisms of detoxification. The methods of formaldehyde sensing are also described with a focus on the formaldehyde responsive transcription factors HxlR, FrmR and NmlR. Finally, the physiological relevance of detoxification systems for formaldehyde in bacterial pathogens is discussed.

  7. Actinobaculum schaalii: A truly emerging pathogen?

    Science.gov (United States)

    Prigent, G.; Perillaud, C.; Amara, M.; Coutard, A.; Blanc, C.; Pangon, B.

    2016-01-01

    Actinobaculum schaalii is a Gram-positive facultative anaerobe bacillus. It is a commensal organism of the genitourinary tract. Its morphology is nonspecific. Aerobic culture is tedious, and identification techniques have long been inadequate. Thus, A. schaalii has often been considered as a nonpathogen bacterium or a contaminant. Its pathogenicity is now well described in urinary tract infections, and infections in other sites have been reported. This pathogen is considered as an emerging one following the growing use of mass spectrometry identification. In this context, the aim of our study was to evaluate the number of isolations of A. schaalii before and after the introduction of mass spectrometry in our hospital and to study the clinical circumstances in which isolates were found. PMID:27014462

  8. Microretroreflector-sedimentation immunoassays for pathogen detection.

    Science.gov (United States)

    Garvey, Gavin; Shakarisaz, David; Ruiz-Ruiz, Federico; Hagström, Anna E V; Raja, Balakrishnan; Pascente, Carmen; Kar, Archana; Kourentzi, Katerina; Rito-Palomares, Marco; Ruchhoeft, Paul; Willson, Richard C

    2014-09-16

    Point-of-care detection of pathogens is medically valuable but poses challenging trade-offs between instrument complexity and clinical and analytical sensitivity. Here we introduce a diagnostic platform utilizing lithographically fabricated micron-scale forms of cubic retroreflectors, arguably one of the most optically detectable human artifacts, as reporter labels for use in sensitive immunoassays. We demonstrate the applicability of this novel optical label in a simple assay format in which retroreflector cubes are first mixed with the sample. The cubes are then allowed to settle onto an immuno-capture surface, followed by inversion for gravity-driven removal of nonspecifically bound cubes. Cubes bridged to the capture surface by the analyte are detected using inexpensive, low-numerical aperture optics. For model bacterial and viral pathogens, sensitivity in 10% human serum was found to be 10(4) bacterial cells/mL and 10(4) virus particles/mL, consistent with clinical utility.

  9. Efficacy of miswak on oral pathogens.

    Science.gov (United States)

    Sukkarwalla, Adnan; Ali, Salima Mehboob; Lundberg, Pranee; Tanwir, Farzeen

    2013-05-01

    The oral cavity harbors a diverse and abundant number of complex oral pathogens causing different oral diseases. The development of dental caries and periodontal diseases has been found to be closely associated with various gram positive and gram negative microrganisms. Miswak, a natural toothbrush, has been documented as a potent antibacterial aid and its use is encouraged in different countries because of its good taste, texture, availability, cost and beneficial effect on teeth and supporting tissues. Different researches have been carried out to evaluate the antimicrobial effects of Miswak. This review encompasses the efficacy of Miswak on suppression of oral pathogens with respect to conducted on fungi as well as cariogenic, periodontal and endodontic bacteria.

  10. Molecular mechanisms of Escherichia coli pathogenicity.

    Science.gov (United States)

    Croxen, Matthew A; Finlay, B Brett

    2010-01-01

    Escherichia coli is a remarkable and diverse organism. This normally harmless commensal needs only to acquire a combination of mobile genetic elements to become a highly adapted pathogen capable of causing a range of diseases, from gastroenteritis to extraintestinal infections of the urinary tract, bloodstream and central nervous system. The worldwide burden of these diseases is staggering, with hundreds of millions of people affected annually. Eight E. coli pathovars have been well characterized, and each uses a large arsenal of virulence factors to subvert host cellular functions to potentiate its virulence. In this Review, we focus on the recent advances in our understanding of the different pathogenic mechanisms that are used by various E. coli pathovars and how they cause disease in humans.

  11. Susceptibility of Postharvest Pathogens to Esential Oils

    Directory of Open Access Journals (Sweden)

    Božik M.

    2017-09-01

    Full Text Available Antimicrobial volatile substances from plants represent alternatives to synthetic pesticides and food preservatives. In this study, the compositions of some essential oils were determined by gas chromatography with mass spectrometry, and the inhibitory properties of the essential oils and their components against the bacterial postharvest pathogens Pectobacterium carotovorum subsp. carotovorum (CCM 1008, Pseudomonas syringae (CCM 7018, Xanthomonas campestris (CCM 22 were determined by the microdilution method. Essential oils from oregano, cinnamon, lemongrass, lavender, clove, rosemary, tea tree, eucalyptus, garlic, and ginger and their components cinnamaldehyde, eugenol, thymol, and carvacrol were used in the tests. The essential oil components exhibited strong antibacterial activity against all tested bacteria. The oregano and cinnamon essential oils were most effective. The rosemary, lavender, tea tree, eucalyptus, garlic, and ginger oils were not effective at the tested concentrations. In conclusion, certain essential oils, particularly their components, are highly effective and could be used for the control of postharvest bacterial pathogens.

  12. Protein sequence database for pathogenic arenaviruses

    Science.gov (United States)

    Bui, Huynh-Hoa; Botten, Jason; Fusseder, Nicolas; Pasquetto, Valerie; Mothe, Bianca; Buchmeier, Michael J; Sette, Alessandro

    2007-01-01

    Background Arenaviruses are a family of rodent-borne viruses that cause several hemorrhagic fevers. These diseases can be devastating and are often lethal. Herein, to aid in the design and development of diagnostics, treatments and vaccines for arenavirus infections, we have developed a database containing protein sequences from the seven pathogenic arenaviruses (Junin, Guanarito, Sabia, Machupo, Whitewater Arroyo, Lassa and LCMV). Results The database currently contains a non-redundant set of 333 protein sequences which were manually annotated. All entries were linked to NCBI and cited PubMed references. The database has a convenient query interface including BLAST search. Sequence variability analyses were also performed and the results are hosted in the database. Conclusion The database is available at and can be used to aid in studies that require proteomic information from pathogenic arenaviruses. PMID:17288609

  13. Whole-genome sequencing of veterinary pathogens

    DEFF Research Database (Denmark)

    Ronco, Troels

    using whole-genome sequencing. The results showed that NELoc-1 and -3 and the two virulence genes netB and cnaA were significantly more associated with NE isolates from chickens compared to NE isolates from turkeys. Only NELoc-2 was associated with NE isolates from both turkeys and chickens. A putative......-electrophoresis and single-locus sequencing has been widely used to characterize such types of veterinary pathogens. However, DNA sequencing techniques have become fast and cost effective in recent years and whole-genome sequencing data provide a much higher discriminative power and reproducibility than any...... of the traditional molecular techniques. In this PhD project three important veterinary pathogens (Clostridium perfringens, Escherichia coli and Staphylococcus aureus) were investigated using whole-genome sequencing. This was done in five different scientific papers which all have been published. Paper I and II...

  14. Fusobacterium nucleatum: an emerging gut pathogen?

    Science.gov (United States)

    Allen-Vercoe, Emma; Strauss, Jaclyn; Chadee, Kris

    2011-09-01

    The Gram-negative, non-sporulating, obligately anaerobic species, Fusobacterium nucleatum, is rapidly gaining notoriety as a pathogen with a surprising number of associated diseases. Recently, we have found that F. nucleatum is a more common resident of the GI tract than originally thought, and thus, through several studies, we have attempted to determine its gut-relevant potential for virulence. We have found that F. nucleatum possesses a number of pathogenic traits with relevance to gut diseases such as inflammatory bowel disease (IBD), however, we have also documented strain-associated differences in virulence. An intriguing picture emerges that paints F. nucleatum as both conferring beneficial as well as detrimental effects on host cells; and we suggest that the ultimate effects of F. nucleatum infection in the gut are a consequence of the microbes with which this species aggregates.

  15. OSHA Bloodborne Pathogens Standards Exposure Control Plan

    Science.gov (United States)

    Luhrs, Caro Elise; Teitelbaum, Rita

    1993-01-01

    The Hummer Associates Exposure Control Plan is designed to reduce significant occupational exposure to bloodborne pathogens and infectious materials for Hummer Associates health care personnel. Under universal precautions, all patients and all body fluids are considered potentially infectious for bloodborne pathogens. Medical personnel need not be at increased risk if universal precautions are correctly understood and followed. This program covers all employees who could reasonably anticipate contact with blood or other potentially infectious materials during the performance of their job responsibilities. Although HIV and hepatitis B are mentioned most often, this program applies to all bloodborne diseases. The two main components needed to implement this program are universal precautions and engineering/work practice controls. This program covers all employees who may have occupational exposure to blood or other potentially infectious materials. Other aspects of this program are discussed.

  16. Main Concerns of Pathogenic Microorganisms in Meat

    Science.gov (United States)

    Nørrung, Birgit; Andersen, Jens Kirk; Buncic, Sava

    Although various foods can serve as sources of foodborne illness, meat and meat products are important sources of human infections with a variety of foodborne pathogens, i.e. Salmonella spp., Campylobacter jejuni/coli, Yersinia enterocolitica, Verotoxigenic E. coli and, to some extent, Listeria monocytogenes. All these may be harboured in the gastrointestinal tract of food-producing animals. The most frequent chain of events leading to meat-borne illness involves food animals, which are healthy carriers of the pathogens that are subsequently transferred to humans through production, handling and consumption of meat and meat products. Occurrences of Salmonella spp., C. jejuni/coli, Y. enterocolitica and Verotoxigenic E. coli in fresh red meat vary relatively widely, although most often are between 1 and 10%, depending on a range of factors including the organism, geographical factors, farming and/or meat production practices.

  17. Highly Virulent Non-O157 Enterohemorrhagic Escherichia coli (EHEC) Serotypes Reflect Similar Phylogenetic Lineages, Providing New Insights into the Evolution of EHEC.

    Science.gov (United States)

    Eichhorn, Inga; Heidemanns, Katrin; Semmler, Torsten; Kinnemann, Bianca; Mellmann, Alexander; Harmsen, Dag; Anjum, Muna F; Schmidt, Herbert; Fruth, Angelika; Valentin-Weigand, Peter; Heesemann, Jürgen; Suerbaum, Sebastian; Karch, Helge; Wieler, Lothar H

    2015-10-01

    Enterohemorrhagic Escherichia coli (EHEC) is the causative agent of bloody diarrhea and extraintestinal sequelae in humans, most importantly hemolytic-uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP). Besides the bacteriophage-encoded Shiga toxin gene (stx), EHEC harbors the locus of enterocyte effacement (LEE), which confers the ability to cause attaching and effacing lesions. Currently, the vast majority of EHEC infections are caused by strains belonging to five O serogroups (the "big five"), which, in addition to O157, the most important, comprise O26, O103, O111, and O145. We hypothesize that these four non-O157 EHEC serotypes differ in their phylogenies. To test this hypothesis, we used multilocus sequence typing (MLST) to analyze a large collection of 250 isolates of these four O serogroups, which were isolated from diseased as well as healthy humans and cattle between 1952 and 2009. The majority of the EHEC isolates of O serogroups O26 and O111 clustered into one sequence type complex, STC29. Isolates of O103 clustered mainly in STC20, and most isolates of O145 were found within STC32. In addition to these EHEC strains, STC29 also included stx-negative E. coli strains, termed atypical enteropathogenic E. coli (aEPEC), yet another intestinal pathogenic E. coli group. The finding that aEPEC and EHEC isolates of non-O157 O serogroups share the same phylogeny suggests an ongoing microevolutionary scenario in which the phage-encoded Shiga toxin gene stx is transferred between aEPEC and EHEC. As a consequence, aEPEC strains of STC29 can be regarded as post- or pre-EHEC isolates. Therefore, STC29 incorporates phylogenetic information useful for unraveling the evolution of EHEC. Copyright © 2015, Eichhorn et al.

  18. Pathogens spectrum of deep human mycosis

    Directory of Open Access Journals (Sweden)

    A. B. Kulko

    2012-01-01

    Full Text Available The article describes characteristics of two different etiology groups of deep human mycosis — extremely dangerous endemic deep mycoses (histoplasmosis, coccidioidomycosis, blastomycosis, paracoccidioidomycosis, penicilliosis due to Penicillium marneffei and opportunistic deep mycosis (candidiasis, cryptococcosis, aspergillosis, mucormycosis. Information on fungal pathogens and antifungal agents is presented. The own results of cultural studies obtained during pneumomycosis diagnosis in patients with tuberculosis are shown.

  19. Synthetic Nanovaccines Against Respiratory Pathogens (SYNARP)

    Science.gov (United States)

    2012-07-01

    increasing amounts of antigen-specific antibody at this time point. Neutralizing activity against an equine infectious anemia virus expressing the...respiratory infections, the leading cause of outpatient illness and a major cause of infectious disease hospitalization in U.S. military personnel...day virus challenged). To determine the minimum amount of virus that would give a 100% mouse infectious dose (MID100) of the low pathogenic

  20. Pathogenic and opportunistic microorganisms in caves

    Directory of Open Access Journals (Sweden)

    Sanchez-Moral Sergio

    2010-01-01

    Full Text Available With today’s leisure tourism, the frequency of visits to many caves makes it necessary to know about possible potentially pathogenic microorganisms in caves, determine their reservoirs, and inform the public about the consequences of such visits. Our data reveal that caves could be a potential danger to visitors because of the presence of opportunistic microorganisms, whose existence and possible development in humans is currently unknown.

  1. Pathogen survival in chorizos: ecological factors.

    Science.gov (United States)

    Hew, Carrie M; Hajmeer, Maha N; Farver, Thomas B; Riemann, Hans P; Glover, James M; Cliver, Dean O

    2006-05-01

    This study addressed health risks from ethnic sausages produced on a small scale, without inspection, in California and elsewhere. Mexican-style chorizo, a raw pork sausage that is not cured, fermented, or smoked, was contaminated experimentally in the batter with Escherichia coli O157:H7, Listeria monocytogenes, or Salmonella serotypes and stuffed into natural casings. Formulations were based on a market survey in California. Physical parameters that were controlled were pH, water activity (a(w)), and storage temperature. The pH was adjusted with vinegar, stabilizing at 5.0 within 24 h. Initial a(w) levels adjusted with salt were 0.97, 0.95, 0.93, 0.90, and 0.85; levels declined with time because of evaporation. Pathogen numbers declined with storage up to 7 days, with few brief exceptions. Main effects and interactions of constant temperature and pH with declining a(w) on survival of the pathogens were determined. Maximum death rates occurred at higher a(w) for E. coli O157:H7 and Salmonella than for L. monocytogenes. Salt used to adjust a(w) affected palatability. Spices (black pepper, chili pepper, chili powder, cumin, garlic, guajillo pepper, oregano, and paprika) comprised another, potentially significant aspect of the sausage formulation. Some (notably black pepper and cumin) carried an indigenous microflora that contributed significantly to the microbial load of the sausage batter. Only undiluted fresh and powdered garlic exhibited a significant antimicrobial effect on the pathogens. Although each of the tested formulations caused death of the inoculated pathogens, none of the death rates was sufficiently rapid to ensure safety within the probable shelf life of the product.

  2. Outer membrane proteins of pathogenic spirochetes

    OpenAIRE

    Cullen, Paul A.; Haake, David A.; Adler, Ben

    2004-01-01

    Pathogenic spirochetes are the causative agents of several important diseases including syphilis, Lyme disease, leptospirosis, swine dysentery, periodontal disease and some forms of relapsing fever. Spirochetal bacteria possess two membranes and the proteins present in the outer membrane are at the site of interaction with host tissue and the immune system. This review describes the current knowledge in the field of spirochetal outer membrane protein (OMP) biology. What is known concerning bi...

  3. Comparative analysis of twelve Dothideomycete plant pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Ohm, Robin; Aerts, Andrea; Salamov, Asaf; Goodwin, Stephen B.; Grigoriev, Igor

    2011-03-11

    The Dothideomycetes are one of the largest and most diverse groups of fungi. Many are plant pathogens and pose a serious threat to agricultural crops grown for biofuel, food or feed. Most Dothideomycetes have only a single host and related Dothideomycete species can have very diverse host plants. Twelve Dothideomycete genomes have currently been sequenced by the Joint Genome Institute and other sequencing centers. They can be accessed via Mycocosm which has tools for comparative analysis

  4. Cellphones A Modern Stayhouse For Bacterial Pathogens

    OpenAIRE

    Usha Arora; Pushpa Devi; Aarti Chadha; Sita Malhotra

    2009-01-01

    Cellphones are increasingly used by health care personnels for communication. These can harbour variouspotential pathogens and become an exogenous source of nosocomial infections. A total of 160 cellphonesbelonging to doctors and paramedical staff working in various departments at govt. medical college andhospital, Amritsar were screened for bacterial isolates. Sterile swabs moistened with nutrient broth wereused to swab the front, back and the sides of the cellphones and were subjected to cu...

  5. Protein sequence database for pathogenic arenaviruses

    OpenAIRE

    Bui, HH; Botten, J; Fusseder, N; Pasquetto, V; Mothe, B; Buchmeier, MJ; Sette, A

    2007-01-01

    Background: Arenaviruses are a family of rodent-borne viruses that cause several hemorrhagic fevers. These diseases can be devastating and are often lethal. Herein, to aid in the design and development of diagnostics, treatments and vaccines for arenavirus infections, we have developed a database containing protein sequences from the seven pathogenic arenaviruses (Junin, Guanarito, Sabia, Machupo, Whitewater Arroyo, Lassa and LCMV). Results: The database currently contains a non-redundant set...

  6. Occurrence of antimicrobial resistance among bacterial pathogens

    OpenAIRE

    Hendriksen, Rene S.; Mevius, Dik J.; Schroeter, Andreas; Teale, Christopher; Jouy, Eric; Butaye, Patrick; Franco, Alessia; Utinane, Andra; Amado, Alice; Moreno, Miguel; Greko, Christina; Stärk, Katharina D.C.; Berghold, Christian; Myllyniemi, Anna-Liisa; Hoszowski, Andrzej

    2008-01-01

    Background: The project "Antibiotic resistance in bacteria of animal origin – II" (ARBAO-II) was funded by the European Union (FAIR5-QLK2-2002-01146) for the period 2003–05. The aim of this project was to establish a program for the continuous monitoring of antimicrobial susceptibility of pathogenic and indicator bacteria from food animals using validated and harmonised methodologies. In this report the first data on the occurrence of antimicrobial resistance among bacteria cau...

  7. PHIDIAS- Pathogen Host Interaction Data Integration and Analysis

    Indian Academy of Sciences (India)

    PHIDIAS- Pathogen Host Interaction Data Integration and Analysis- allows searching of integrated genome sequences, conserved domains and gene expressions data related to pathogen host interactions in high priority agents for public health and security ...

  8. Plant pathology: monitoring a pathogen-targeted host protein.

    Science.gov (United States)

    Ellis, Jeff; Dodds, Peter

    2003-05-13

    A plant protein RIN4 is targeted and modified by bacterial pathogens as part of the disease process. At least two host resistance proteins monitor this pathogen interference and trigger the plant's defence responses.

  9. Surveillance of multidrug resistant bacteria pathogens from female ...

    African Journals Online (AJOL)

    Highest sensitivity was observed with gatifloxacin, imipenam and piperacillin and tazobactum. Thus, according to this study, these antibiotics can be recommended against multi drug resistant bacteria pathogens. Keywords: Multidrug resistance, female infertility, bacteria pathogens. African Journal of Biotechnology Vol.

  10. Biocontrol interventions for inactivation of foodborne pathogens on produce

    Science.gov (United States)

    Post-harvest interventions for control of foodborne pathogens on minimally processed foods are crucial for food safety. Biocontrol interventions have the primary objective of developing novel antagonists in combinations with physical and chemical interventions to inactivate pathogenic microbes. Ther...

  11. Sensitivity of mechanically transmitted pathogens to different disinfectants

    Science.gov (United States)

    The intensive hands-on activities of greenhouse tomato propagation and production favor the spread of mechanically transmitted pathogens, particularly Clavibacter michiganensis subsp. michiganensis (Cmm), viruses, viroids, and Botrytis cinerea. These pathogens can spread during crop handling, graft...

  12. Swiss Army Pathogen: The Salmonella Entry Toolkit

    Directory of Open Access Journals (Sweden)

    Peter J. Hume

    2017-08-01

    Full Text Available Salmonella causes disease in humans and animals ranging from mild self-limiting gastroenteritis to potentially life-threatening typhoid fever. Salmonellosis remains a considerable cause of morbidity and mortality globally, and hence imposes a huge socio-economic burden worldwide. A key property of all pathogenic Salmonella strains is the ability to invade non-phagocytic host cells. The major determinant of this invasiveness is a Type 3 Secretion System (T3SS, a molecular syringe that injects virulence effector proteins directly into target host cells. These effectors cooperatively manipulate multiple host cell signaling pathways to drive pathogen internalization. Salmonella does not only rely on these injected effectors, but also uses several other T3SS-independent mechanisms to gain entry into host cells. This review summarizes our current understanding of the methods used by Salmonella for cell invasion, with a focus on the host signaling networks that must be coordinately exploited for the pathogen to achieve its goal.

  13. Pathogenic conversion of coagulase-negative staphylococci.

    Science.gov (United States)

    Yu, Wenqi; Kim, Hwan Keun; Rauch, Sabine; Schneewind, Olaf; Missiakas, Dominique

    2017-02-01

    Humans and animals are colonized by members of the genus Staphylococcus, however only some of these species evolved to cause invasive disease. The genetic basis for conversion of commensal staphylococci into pathogens is not known. We hypothesized that Staphylococcus aureus genes for coagulation and agglutination in vertebrate blood (coa, vwb and clfA) may support pathogenic conversion. Expression of coa and vwb in Staphylococcus epidermidis or Staphylococcus simulans supported a coagulase-positive phenotype but not the ability to cause disease in a mouse model of bloodstream infection. However, the simultaneous expression of coa, vwb and clfA in coagulase-negative staphylococci enabled bacterial agglutination in plasma and enhanced survival of S. simulans in human whole blood. Agglutination of S. simulans in the bloodstream of infected mice upon expression of coa, vwb and clfA provided also a mean for dissemination and replication in distal organs. Thus, the acquisition of genes for bacterial agglutination with fibrin appear sufficient for the conversion of commensal staphylococci into invasive pathogens. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  14. Review of soybean resistance to pathogens

    Directory of Open Access Journals (Sweden)

    Vidić Miloš

    2013-01-01

    Full Text Available This paper presents an overview of the research on soybean resistance to pathogens. The review included most harmful agents of soybean diseases in Serbia, as well as those that are potentially harmful. Development and cultivation of resistant cultivars is the most efficient, economical and environmentally acceptable control measure for plant disease. It points to the variability in pathogenicity (physiological races of parasites, especially expressed in Phytophthora sojae, Peronospora manshurica and Pseudomonas syringae pv. glycinea, which requires continuous breeding for resistance. Resistant, partially resistant and moderately susceptible genotypes, which are used as donors of resistance genes to different pathogens, are listed in this paper. Also, avirulent genes in the parasite and resistance genes in soybean are indicated. Gene mapping significantly contributes to better understanding of the mode of inheritance and consequently, more efficient breeding for disease resistance. Significant improvement is expected by using molecular techniques, especially in dealing with Sclerotinia sclerotiorum, Pseudomonas syringae pv. glycinea and Phomopsis longicolla. For these parasites only partial resistance has been reported but not complete resistance.

  15. Clostridium difficile is an autotrophic bacterial pathogen.

    Directory of Open Access Journals (Sweden)

    Michael Köpke

    Full Text Available During the last decade, Clostridium difficile infection showed a dramatic increase in incidence and virulence in the Northern hemisphere. This incessantly challenging disease is the leading cause of antibiotic-associated and nosocomial infectious diarrhea and became life-threatening especially among elderly people. It is generally assumed that all human bacterial pathogens are heterotrophic organisms, being either saccharolytic or proteolytic. So far, this has not been questioned as colonization of the human gut gives access to an environment, rich in organic nutrients. Here, we present data that C. difficile (both clinical and rumen isolates is also able to grow on CO2+H2 as sole carbon and energy source, thus representing the first identified autotrophic bacterial pathogen. Comparison of several different strains revealed high conservation of genes for autotrophic growth and showed that the ability to use gas mixtures for growth decreases or is lost upon prolonged culturing under heterotrophic conditions. The metabolic flexibility of C. difficile (heterotrophic growth on various substrates as well as autotrophy could allow the organism in the gut to avoid competition by niche differentiation and contribute to its survival when stressed or in unfavorable conditions that cause death to other bacteria. This may be an important trait for the pathogenicity of C. difficile.

  16. The Venturia Apple Pathosystem: Pathogenicity Mechanisms and Plant Defense Responses

    Directory of Open Access Journals (Sweden)

    Gopaljee Jha

    2009-01-01

    Full Text Available Venturia inaequalis is the causal agent of apple scab, a devastating disease of apple. We outline several unique features of this pathogen which are useful for molecular genetics studies intended to understand plant-pathogen interactions. The pathogenicity mechanisms of the pathogen and overview of apple defense responses, monogenic and polygenic resistance, and their utilization in scab resistance breeding programs are also reviewed.

  17. Identifying Pathogenicity Islands in Bacterial Pathogenomics Using Computational Approaches

    OpenAIRE

    Che, Dongsheng; Hasan, Mohammad Shabbir; Chen, Bernard

    2014-01-01

    High-throughput sequencing technologies have made it possible to study bacteria through analyzing their genome sequences. For instance, comparative genome sequence analyses can reveal the phenomenon such as gene loss, gene gain, or gene exchange in a genome. By analyzing pathogenic bacterial genomes, we can discover that pathogenic genomic regions in many pathogenic bacteria are horizontally transferred from other bacteria, and these regions are also known as pathogenicity islands (PAIs). PAI...

  18. PathogenMIPer: a tool for the design of molecular inversion probes to detect multiple pathogens

    Directory of Open Access Journals (Sweden)

    Akhras Michael

    2006-11-01

    Full Text Available Abstract Background Here we describe PathogenMIPer, a software program for designing molecular inversion probe (MIP oligonucleotides for use in pathogen identification and detection. The software designs unique and specific oligonucleotide probes targeting microbial or other genomes. The tool tailors all probe sequence components (including target-specific sequences, barcode sequences, universal primers and restriction sites and combines these components into ready-to-order probes for use in a MIP assay. The system can harness the genetic variability available in an entire genome in designing specific probes for the detection of multiple co-infections in a single tube using a MIP assay. Results PathogenMIPer can accept sequence data in FASTA file format, and other parameter inputs from the user through a graphical user interface. It can design MIPs not only for pathogens, but for any genome for use in parallel genomic analyses. The software was validated experimentally by applying it to the detection of human papilloma virus (HPV as a model system, which is associated with various human malignancies including cervical and skin cancers. Initial tests of laboratory samples using the MIPs developed by the PathogenMIPer to recognize 24 different types of HPVs gave very promising results, detecting even a small viral load of single as well as multiple infections (Akhras et al, personal communication. Conclusion PathogenMIPer is a software for designing molecular inversion probes for detection of multiple target DNAs in a sample using MIP assays. It enables broader use of MIP technology in the detection through genotyping of pathogens that are complex, difficult-to-amplify, or present in multiple subtypes in a sample.

  19. Isolation of antibiotic-resistant pathogenic and potentially ...

    African Journals Online (AJOL)

    Objective: Isolation of potentially pathogenic bacteria from carpets in hospitals has been reported earlier, but not from carpets in mosques. The aim of the present study is to determine the pathogenic and potentially pathogenic bacteria that may exist on the carpets of mosques in Tripoli, Libya. Methods: Dust samples from ...

  20. Comparison of procedures to evaluate the pathogenicity of ...

    African Journals Online (AJOL)

    Ceratocystis fimbriata sensu lato(s.l.) is an important pathogen of Eucalyptus. Pathogenicity of isolates has typically been evaluated by inoculating seedlings under greenhouse conditions. It is, however, not clear how accurately this reflects pathogenicity under field conditions. In this study, five techniques to potentially ...

  1. Isolation and characterization of seed-Borne pathogenic bacteria ...

    African Journals Online (AJOL)

    The isolated bacterial strains were identified based on colony morphology, biochemical, serological and pathogenicity tests. Acidovorax avenae subsp. avenae, the causal agent of brown stripe was detected in 63% of the seed samples tested indicating that this pathogen is widely distributed in Tanzania. Other pathogens ...

  2. A study of pathogenic organisms habitation preferences in fish organs

    African Journals Online (AJOL)

    Fish pathogens may attack any convenient part of the host. But studies indicate that pathogens of fish tend to reveal their preference for particular fish organs. The present study set out with the objective of identifying the organs most inhabited by these pathogenic organisms in fishes. Collecting samples of Clarias gariepinus ...

  3. Cladosporium fulvum effector proteins and their role in pathogen virulence

    NARCIS (Netherlands)

    Esse, van H.P.

    2008-01-01

    Cladosporium fulvum (syn. Passalora fulva) is a biotrophic fungal pathogen that causes leaf mould of tomato (Solanum esculentum). Chapter 1 is a “pathogen profile” describing the biology of the pathogen. During growth in the leaf apoplast, the intercellular space surrounding the mesophyll cells, the

  4. Host-pathogen interactions: A cholera surveillance system

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Aaron T.

    2016-02-22

    Bacterial pathogen-secreted proteases may play a key role in inhibiting a potentially widespread host-pathogen interaction. Activity-based protein profiling enabled the identification of a major Vibrio cholerae serine protease that limits the ability of a host-derived intestinal lectin to bind to the bacterial pathogen in vivo.

  5. Pathogen propagation in cultured three-dimensional tissue mass

    Science.gov (United States)

    Goodwin, Thomas J. (Inventor); Spaulding, Glenn F. (Inventor); Wolf, David A. (Inventor)

    2000-01-01

    A process for propagating a pathogen in a three-dimensional tissue mass cultured at microgravity conditions in a culture vessel containing culture media and a culture matrix is provided. The three-dimensional tissue mass is inoculated with a pathogen and pathogen replication in the cells of the tissue mass achieved.

  6. Isolation of antibiotic-resistant pathogenic and potentially ...

    African Journals Online (AJOL)

    2010-09-13

    Sep 13, 2010 ... aureus. Conclusion: Contamination of carpets in mosques of Tripoli with antibiotic-resistant pathogenic and potentially pathogenic bacteria may pose a .... and S. aureus were detected in carpets from the mosques in Tripoli. Salmonella spp. are important foodborne pathogens worldwide. They are the most.

  7. Phylogeographic Diversity of Pathogenic and Non-Pathogenic Hantaviruses in Slovenia

    Science.gov (United States)

    Korva, Miša; Knap, Nataša; Resman Rus, Katarina; Fajs, Luka; Grubelnik, Gašper; Bremec, Matejka; Knapič, Tea; Trilar, Tomi; Avšič Županc, Tatjana

    2013-01-01

    Slovenia is a very diverse country from a natural geography point of view, with many different habitats within a relatively small area, in addition to major geological and climatic differences. It is therefore not surprising that several small mammal species have been confirmed to harbour hantaviruses: A. flavicollis (Dobrava virus), A. agrarius (Dobrava virus–Kurkino), M. glareolus (Puumala virus), S. areanus (Seewis virus), M. agrestis, M. arvalis and M. subterraneus (Tula virus). Three of the viruses, namely the Dobrava, Dobrava–Kurkino and Puumala viruses, cause disease in humans, with significant differences in the severity of symptoms. Due to changes in haemorrhagic fever with renal syndrome cases (HFRS) epidemiology, a detailed study on phylogenetic diversity and molecular epidemiology of pathogenic and non-pathogenic hantaviruses circulating in ecologically diverse endemic regions was performed. The study presents one of the largest collections of hantavirus L, M and S sequences obtained from hosts and patients within a single country. Several genetic lineages were determined for each hantavirus species, with higher diversity among non-pathogenic compared to pathogenic viruses. For pathogenic hantaviruses, a significant geographic clustering of human- and rodent-derived sequences was confirmed. Several geographic and ecological factors were recognized as influencing and limiting the formation of endemic areas. PMID:24335778

  8. Resequencing Pathogen Microarray (RPM) for prospective detection and identification of emergent pathogen strains and variants

    Science.gov (United States)

    Tibbetts, Clark; Lichanska, Agnieszka M.; Borsuk, Lisa A.; Weslowski, Brian; Morris, Leah M.; Lorence, Matthew C.; Schafer, Klaus O.; Campos, Joseph; Sene, Mohamadou; Myers, Christopher A.; Faix, Dennis; Blair, Patrick J.; Brown, Jason; Metzgar, David

    2010-04-01

    High-density resequencing microarrays support simultaneous detection and identification of multiple viral and bacterial pathogens. Because detection and identification using RPM is based upon multiple specimen-specific target pathogen gene sequences generated in the individual test, the test results enable both a differential diagnostic analysis and epidemiological tracking of detected pathogen strains and variants from one specimen to the next. The RPM assay enables detection and identification of pathogen sequences that share as little as 80% sequence similarity to prototype target gene sequences represented as detector tiles on the array. This capability enables the RPM to detect and identify previously unknown strains and variants of a detected pathogen, as in sentinel cases associated with an infectious disease outbreak. We illustrate this capability using assay results from testing influenza A virus vaccines configured with strains that were first defined years after the design of the RPM microarray. Results are also presented from RPM-Flu testing of three specimens independently confirmed to the positive for the 2009 Novel H1N1 outbreak strain of influenza virus.

  9. Mycological assessment of sediments in Ligurian beaches in the Northwestern Mediterranean: pathogens and opportunistic pathogens.

    Science.gov (United States)

    Salvo, Vanessa-Sarah; Fabiano, Mauro

    2007-05-01

    Sediments of five Ligurian beaches in compliance with European Union bathing water regulations were studied based on the characteristics of the fungal assemblage during the tourism season. Among the 179 taxa of filamentous fungi isolated, 120 were opportunistic pathogens, such as Acremonium sp., and the genus Penicillium was also present as the pathogenic species P. citrinum. Furthermore, 5% of the total filamentous fungi belonged to the dermatophyte genus Microsporum, whose species can cause mycoses. Beach sediments showed elevated densities of opportunistic pathogens, of pathogenic filamentous fungi, and of yeasts during the tourism season. Although monitoring of beach sediments for microbiological contamination is not mandatory, and disease transmission from sediments has not yet been demonstrated, our study suggests that beach sediments may act as a reservoir of potential pathogens, including fungi. In addition, the mycoflora displayed high sensitivity to critical environmental situations in the beaches studied. Therefore, the fungal community can be a useful tool for assessing the quality of sandy beaches in terms of sanitary and environmental quality.

  10. Phylogeographic Diversity of Pathogenic and Non-Pathogenic Hantaviruses in Slovenia

    Directory of Open Access Journals (Sweden)

    Miša Korva

    2013-12-01

    Full Text Available Slovenia is a very diverse country from a natural geography point of view, with many different habitats within a relatively small area, in addition to major geological and climatic differences. It is therefore not surprising that several small mammal species have been confirmed to harbour hantaviruses: A. flavicollis (Dobrava virus, A. agrarius (Dobrava virus–Kurkino, M. glareolus (Puumala virus, S. areanus (Seewis virus,M. agrestis, M. arvalis and M. subterraneus (Tula virus. Three of the viruses, namely the Dobrava, Dobrava–Kurkino and Puumala viruses, cause disease in humans, with significant differences in the severity of symptoms. Due to changes in haemorrhagic fever with renal syndrome cases (HFRS epidemiology, a detailed study on phylogenetic diversity and molecular epidemiology of pathogenic and non-pathogenic hantaviruses circulating in ecologically diverse endemic regions was performed. The study presents one of the largest collections of hantavirus L, M and S sequences obtained from hosts and patients within a single country. Several genetic lineages were determined for each hantavirus species, with higher diversity among non-pathogenic compared to pathogenic viruses. For pathogenic hantaviruses, a significant geographic clustering of human- and rodent-derived sequences was confirmed. Several geographic and ecological factors were recognized as influencing and limiting the formation of endemic areas.

  11. Strategies of Intracellular Pathogens for Obtaining Iron from the Environment

    Directory of Open Access Journals (Sweden)

    Nidia Leon-Sicairos

    2015-01-01

    Full Text Available Most microorganisms are destroyed by the host tissues through processes that usually involve phagocytosis and lysosomal disruption. However, some organisms, called intracellular pathogens, are capable of avoiding destruction by growing inside macrophages or other cells. During infection with intracellular pathogenic microorganisms, the element iron is required by both the host cell and the pathogen that inhabits the host cell. This minireview focuses on how intracellular pathogens use multiple strategies to obtain nutritional iron from the intracellular environment in order to use this element for replication. Additionally, the implications of these mechanisms for iron acquisition in the pathogen-host relationship are discussed.

  12. The human fungal pathogen Cryptococcus can complete its sexual cycle during a pathogenic association with plants.

    Science.gov (United States)

    Xue, Chaoyang; Tada, Yasuomi; Dong, Xinnian; Heitman, Joseph

    2007-06-14

    Cryptococcus is a globally distributed human fungal pathogen that primarily afflicts immunocompromised individuals. How and why this human fungal pathogen associates with plants and how this environmental niche influences its life cycle remains a mystery. We established Cryptococcus-Arabidopsis and Cryptococcus-Eucalyptus systems and discovered that Cryptococcus proliferates and mates on plant surfaces. Mating efficiency of C. gattii was markedly enhanced on plants and myo-inositol and indole acetic acid were specific plant products that stimulated mating. On Arabidopsis, dwarfing and chlorosis were observed following infection with a fungal mixture of two opposite mating-type strains, but not with either mating-type alone. This infection process is countered by the plant jasmonate-mediated defense mechanism. These findings reveal that Cryptococcus can parasitically interact with plants to complete its sexual cycle, which may impact an understanding of the origin and evolution of both plant and animal fungal pathogens in nature.

  13. Comparative analysis of lipopolysaccharides of pathogenic and intermediately pathogenic Leptospira species.

    Science.gov (United States)

    Patra, Kailash P; Choudhury, Biswa; Matthias, Michael M; Baga, Sheyenne; Bandyopadhya, Keya; Vinetz, Joseph M

    2015-10-30

    Lipopolysaccharides (LPS) are complex, amphipathic biomolecules that constitute the major surface component of Gram-negative bacteria. Leptospira, unlike other human-pathogenic spirochetes, produce LPS, which is fundamental to the taxonomy of the genus, involved in host-adaption and also the target of diagnostic antibodies. Despite its significance, little is known of Leptospira LPS composition and carbohydrate structure among different serovars. LPS from Leptospira interrogans serovar Copenhageni strain L1-130, a pathogenic species, and L. licerasiae serovar Varillal strain VAR 010, an intermediately pathogenic species, were studied. LPS prepared from aqueous and phenol phases were analyzed separately. L. interrogans serovar Copenhageni has additional sugars not found in L. licerasiae serovar Varillal, including fucose (2.7%), a high amount of GlcNAc (12.3%), and two different types of dideoxy HexNAc. SDS-PAGE indicated that L. interrogans serovar Copenhageni LPS had a far higher molecular weight and complexity than that of L. licerasiae serovar Varillal. Chemical composition showed that L. interrogans serovar Copenhageni LPS has an extended O-antigenic polysaccharide consisting of sugars, not present in L. licerasiae serovar Varillal. Arabinose, xylose, mannose, galactose and L-glycero-D-mannoheptose were detected in both the species. Fatty acid analysis by gas chromatography-mass spectrometry (GC-MS) showed the presence of hydroxypalmitate (3-OH-C16:0) only in L. interrogans serovar Copenhageni. Negative staining electron microscopic examination of LPS showed different filamentous morphologies in L. interrogans serovar Copenhageni vs. L. licerasiae serovar Varillal. This comparative biochemical analysis of pathogenic and intermediately pathogenic Leptospira LPS reveals important carbohydrate and lipid differences that underlie future work in understanding the mechanisms of host-adaptation, pathogenicity and vaccine development in leptospirosis.

  14. Identifying Pathogenicity Islands in Bacterial Pathogenomics Using Computational Approaches

    Directory of Open Access Journals (Sweden)

    Dongsheng Che

    2014-01-01

    Full Text Available High-throughput sequencing technologies have made it possible to study bacteria through analyzing their genome sequences. For instance, comparative genome sequence analyses can reveal the phenomenon such as gene loss, gene gain, or gene exchange in a genome. By analyzing pathogenic bacterial genomes, we can discover that pathogenic genomic regions in many pathogenic bacteria are horizontally transferred from other bacteria, and these regions are also known as pathogenicity islands (PAIs. PAIs have some detectable properties, such as having different genomic signatures than the rest of the host genomes, and containing mobility genes so that they can be integrated into the host genome. In this review, we will discuss various pathogenicity island-associated features and current computational approaches for the identification of PAIs. Existing pathogenicity island databases and related computational resources will also be discussed, so that researchers may find it to be useful for the studies of bacterial evolution and pathogenicity mechanisms.

  15. Evolution and genome architecture in fungal plant pathogens.

    Science.gov (United States)

    Möller, Mareike; Stukenbrock, Eva H

    2017-12-01

    The fungal kingdom comprises some of the most devastating plant pathogens. Sequencing the genomes of fungal pathogens has shown a remarkable variability in genome size and architecture. Population genomic data enable us to understand the mechanisms and the history of changes in genome size and adaptive evolution in plant pathogens. Although transposable elements predominantly have negative effects on their host, fungal pathogens provide prominent examples of advantageous associations between rapidly evolving transposable elements and virulence genes that cause variation in virulence phenotypes. By providing homogeneous environments at large regional scales, managed ecosystems, such as modern agriculture, can be conducive for the rapid evolution and dispersal of pathogens. In this Review, we summarize key examples from fungal plant pathogen genomics and discuss evolutionary processes in pathogenic fungi in the context of molecular evolution, population genomics and agriculture.

  16. Volatile metabolites of pathogens: a systematic review.

    Directory of Open Access Journals (Sweden)

    Lieuwe D J Bos

    2013-05-01

    Full Text Available Ideally, invading bacteria are detected as early as possible in critically ill patients: the strain of morbific pathogens is identified rapidly, and antimicrobial sensitivity is known well before the start of new antimicrobial therapy. Bacteria have a distinct metabolism, part of which results in the production of bacteria-specific volatile organic compounds (VOCs, which might be used for diagnostic purposes. Volatile metabolites can be investigated directly in exhaled air, allowing for noninvasive monitoring. The aim of this review is to provide an overview of VOCs produced by the six most abundant and pathogenic bacteria in sepsis, including Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus faecalis, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli. Such VOCs could be used as biological markers in the diagnostic approach of critically ill patients. A systematic review of existing literature revealed 31 articles. All six bacteria of interest produce isopentanol, formaldehyde, methyl mercaptan, and trimethylamine. Since humans do not produce these VOCs, they could serve as biological markers for presence of these pathogens. The following volatile biomarkers were found for identification of specific strains: isovaleric acid and 2-methyl-butanal for Staphylococcus aureus; 1-undecene, 2,4-dimethyl-1-heptane, 2-butanone, 4-methyl-quinazoline, hydrogen cyanide, and methyl thiocyanide for Pseudomonas aeruginosa; and methanol, pentanol, ethyl acetate, and indole for Escherichia coli. Notably, several factors that may effect VOC production were not controlled for, including used culture media, bacterial growth phase, and genomic variation within bacterial strains. In conclusion, VOCs produced by bacteria may serve as biological markers for their presence. Goal-targeted studies should be performed to identify potential sets of volatile biological markers and evaluate the diagnostic accuracy of these markers in critically

  17. Pathogenic bacterial contaminations in hospital cafeteria foods.

    Science.gov (United States)

    Rattanasena, Paweena; Somboonwatthanakul, Issaraporn

    2010-02-01

    This study aims to examine the pathogenic bacterial contaminations in foods sold in hospital cafeteria. A study was conducted between April and September of 2008 using cafeteria located in Mahasarakham provincial hospital, Thailand, as a study area. The cafeteria foods were evaluated for contaminations with Escherichia coli, Staphylococcus aureus, Salmonella typhimurium and Streptococcus faecalis, which have been earlier reported to cause nosocomial outbreaks. Of 33 different types of ready-to-eat foods, the majority (54.54%) were found to have bacteria >10(7) colony forming units per gram of food (cfu g(-1)), whereas 36.36% and only 9.10% of them were found to have bacteria at 10(6)-10(7) and foods were also shown to be contaminated with Escherichia coli (57.57%), followed by Streptococcus faecalis (51.51%), Staphylococcus aureus (48.48%) and Salmonella typhimurium (27.27%), respectively. In contrast, of 7 different types of freshly-made foods, the majority (71.42%) were found to have bacterial foods (42.85%), followed by Escherichia coli and Streptococcus faecalis at equal percentages (14.28%). None of the freshly-made foods were found to be contaminated with Streptococcus typhimurium. The results concluded that a number of ready-to-eat foods sold in the Mahasarakham hospital cafeteria were contaminated with several pathogenic bacteria at unacceptable levels. Healthcare authorities should be more aware that ready-to-eat cafeteria foods that are heavily contaminated with pathogenic bacteria may be harmful to healthcare workers and visitors and may result in nosocomial infections of the patients.

  18. Lawrence Livermore National Laboratory Workshop Characterization of Pathogenicity, Virulence and Host-Pathogen Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, A

    2006-08-30

    The threats of bio-terrorism and newly emerging infectious diseases pose serious challenges to the national security infrastructure. Rapid detection and diagnosis of infectious disease in human populations, as well as characterizing pathogen biology, are critical for reducing the morbidity and mortality associated with such threats. One of the key challenges in managing an infectious disease outbreak, whether through natural causes or acts of overt terrorism, is detection early enough to initiate effective countermeasures. Much recent attention has been directed towards the utility of biomarkers or molecular signatures that result from the interaction of the pathogen with the host for improving our ability to diagnose and mitigate the impact of a developing infection during the time window when effective countermeasures can be instituted. Host responses may provide early signals in blood even from localized infections. Multiple innate and adaptive immune molecules, in combination with other biochemical markers, may provide disease-specific information and new targets for countermeasures. The presence of pathogen specific markers and an understanding of the molecular capabilities and adaptations of the pathogen when it interacts with its host may likewise assist in early detection and provide opportunities for targeting countermeasures. An important question that needs to be addressed is whether these molecular-based approaches will prove useful for early diagnosis, complement current methods of direct agent detection, and aid development and use of countermeasures. Lawrence Livermore National Laboratory (LLNL) will host a workshop to explore the utility of host- and pathogen-based molecular diagnostics, prioritize key research issues, and determine the critical steps needed to transition host-pathogen research to tools that can be applied towards a more effective national bio-defense strategy. The workshop will bring together leading researchers/scientists in the

  19. Campylobacter ureolyticus: an emerging gastrointestinal pathogen?

    LENUS (Irish Health Repository)

    Bullman, Susan

    2011-03-01

    A total of 7194 faecal samples collected over a 1-year period from patients presenting with diarrhoea were screened for Campylobacter spp. using EntericBio(®) , a multiplex-PCR system. Of 349 Campylobacter-positive samples, 23.8% were shown to be Campylobacter ureolyticus, using a combination of 16S rRNA gene analysis and highly specific primers targeting the HSP60 gene of this organism. This is, to the best of our knowledge, the first report of C. ureolyticus in the faeces of patients presenting with gastroenteritis and may suggest a role for this organism as an emerging enteric pathogen.

  20. Acanthamoeba: ecology, pathogenicity and laboratory detection.

    Science.gov (United States)

    Walker, C W

    1996-06-01

    Acanthamoeba spp. are ubiquitous free-living protozoa found in a wide range of environmental niches. They are resistant to disinfectants, temperature variation and desiccation and are responsible for two recognised diseases in humans, granulomatous amoebic encephalitis and keratitis. Both infections are rare, although the latter is currently receiving more attention following the association between Acanthamoeba and the wearing of contact lenses. Laboratory diagnosis is unusual but not beyond the bounds of most routine clinical microbiology departments. In this review the various aspects surrounding the ecology, pathogenicity and laboratory detection of Acanthamoeba spp. are considered.

  1. Control of indigenous pathogenic bacteria in seafood

    DEFF Research Database (Denmark)

    Huss, Hans Henrik

    1997-01-01

    of disease, are used to place the various seafood products in risk categories and to identify areas of concern. It is concluded that the presence of pathogens in molluscs and the growth of Listeria monocytogenes in lightly preserved fish products are hazards which are presently not under control. In order...... to prevent growth and toxin production by Clostridium botulinum when products are stored at abuse temperature, it is recommended that additional barriers to growth are included in lightly preserved (e.g. cold smoked salmon) and low-heat treated (e.g REPFEDS) products. It is finally pointed out...

  2. Enterobacter agglomerans: the clinically important plant pathogen.

    Science.gov (United States)

    Geere, I. W.

    1977-01-01

    During a 5-month period Enterobacter agglomerans, now described as a member of the phytopathogenic genus Erwinia, was isolated from 13 patients in a general hospital; in 1 patient it was isolated from two sites. In six instances the organism was the sole pathogen isolated, in two instances it may have contributed to infection and in the remaining instances it was probably a transient saprophyte. The strains showed some variation in biochemical reactions but were similar in colonial morphology and were consistently sensitive to several antibiotics. Although this organism is prevalent in the general environment and usually relatively benign, it does have a potential for nosocomial infection. PMID:837319

  3. Survival of foodborne pathogens on inshell walnuts.

    Science.gov (United States)

    Blessington, Tyann; Theofel, Christopher G; Mitcham, Elizabeth J; Harris, Linda J

    2013-09-16

    The survival of Salmonella enterica Enteritidis PT 30 or five-strain cocktails of S. enterica, Escherichia coli O157:H7, and Listeria monocytogenes was evaluated on inshell walnuts during storage. Inshell walnuts were separately inoculated with an aqueous preparation of the pathogens at levels of 10 to 4 log CFU/nut, dried for 24 h, and then stored at either 4 °C or ambient conditions (23-25 °C, 25-35% relative humidity) for 3 weeks to more than 1 year. During the initial 24-h drying period, bacterial levels declined by 0.7 to 2.4 log CFU/nut. After the inoculum dried, further declines of approximately 0.1 log CFU/nut per month of Salmonella Enteritidis PT 30 levels were observed on inshell walnuts stored at 4 °C; at ambient conditions the rates of decline ranged from 0.55 to 2.5 log CFU/nut per month. Rates of decline were generally greater during the first few weeks of storage, particularly at lower inoculum levels. The survival of the five-strain cocktails inoculated at very low levels (under 400 CFU/nut) was determined during storage at ambient conditions. The pathogens could be recovered by either enumeration or enrichment from most samples throughout the 3-month storage period; reductions in bacterial levels from the beginning to end of storage were 0.7, 0.2, and 2.3 log CFU/nut for Salmonella, E. coli O157:H7, and L. monocytogenes, respectively. For 6% of all nut samples (14 of 234 samples), pathogens were isolated from the second but not first 24-h enrichment, suggesting that bacterial cells were viable but not easily culturable. Salmonella-inoculated walnuts were exposed for 2 min to water or a 3% solution of sodium hypochlorite (to mimic commercial brightening) either 24 h or 7 days after inoculation; treated nuts were dried for 24h and held at ambient conditions. Salmonella levels were reduced by less than 0.5 log or 2.4 to 2.6 log CFU/nut on water- or chlorine- treated walnuts, respectively, regardless of postinoculation treatment time. Additional

  4. Epidemiology and pathogenicity of zoonotic streptococci.

    Science.gov (United States)

    Fulde, Marcus; Valentin-Weigand, Peter

    2013-01-01

    Zoonotic infections caused by Streptococcus spp. have been neglected in spite of the fact that frequency and severity of outbreaks increased dramatically in recent years. This may be due to non-identification since respective species are often not considered in human medical diagnostic procedures. On the other hand, an expanding human population concomitant with an increasing demand for food and the increased number of companion animals favour conditions for host species adaptation of animal streptococci. This review aims to give an overview on streptococcal zoonoses with focus on epidemiology and pathogenicity of four major zoonotic species, Streptococcus canis, Streptococcus equi sub. zooepidemicus, Streptococcus iniae and Streptococcus suis.

  5. Bacteriophages in the control of pathogenic vibrios

    DEFF Research Database (Denmark)

    Plaza, Nicolás; Castillo Bermúdez, Daniel Elías; Perez-Reytor, Diliana

    2018-01-01

    constitute a continuing threat for aquaculture. Moreover, the continuous use of antibiotics has been accompanied by an emergence of antibiotic resistance in Vibrio species, implying a necessity for efficient treatments. One promising alternative that emerges is the use of lytic bacteriophages; however......, there are some drawbacks that should be overcome to make phage therapy a widely accepted method. In this work, we discuss about the major pathogenic Vibrio species and the progress, benefits and disadvantages that have been detected during the experimental use of bacteriophages to their control....

  6. Development of saliva-based exposure assays for detecting exposure to waterborne pathogens

    Science.gov (United States)

    Identifying which pathogens we are exposed to can be challenging because many types of pathogens can be found in water and many pathogens have similar symptoms. EPA scientists have developed a simple way to measure human exposure to waterborne pathogens.

  7. Emerging microbial biocontrol strategies for plant pathogens.

    Science.gov (United States)

    Syed Ab Rahman, Sharifah Farhana; Singh, Eugenie; Pieterse, Corné M J; Schenk, Peer M

    2018-02-01

    To address food security, agricultural yields must increase to match the growing human population in the near future. There is now a strong push to develop low-input and more sustainable agricultural practices that include alternatives to chemicals for controlling pests and diseases, a major factor of heavy losses in agricultural production. Based on the adverse effects of some chemicals on human health, the environment and living organisms, researchers are focusing on potential biological control microbes as viable alternatives for the management of pests and plant pathogens. There is a growing body of evidence that demonstrates the potential of leaf and root-associated microbiomes to increase plant efficiency and yield in cropping systems. It is important to understand the role of these microbes in promoting growth and controlling diseases, and their application as biofertilizers and biopesticides whose success in the field is still inconsistent. This review focusses on how biocontrol microbes modulate plant defense mechanisms, deploy biocontrol actions in plants and offer new strategies to control plant pathogens. Apart from simply applying individual biocontrol microbes, there are now efforts to improve, facilitate and maintain long-term plant colonization. In particular, great hopes are associated with the new approaches of using "plant-optimized microbiomes" (microbiome engineering) and establishing the genetic basis of beneficial plant-microbe interactions to enable breeding of "microbe-optimized crops". Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Proteomics of survival structures of fungal pathogens.

    Science.gov (United States)

    Loginov, Dmitry; Šebela, Marek

    2016-09-25

    Fungal pathogens are causal agents of numerous human, animal, and plant diseases. They employ various infection modes to overcome host defense systems. Infection mechanisms of different fungi have been subjected to many comprehensive studies. These investigations have been facilitated by the development of various '-omics' techniques, and proteomics has one of the leading roles in this regard. Fungal conidia and sclerotia could be considered the most important structures for pathogenesis as their germination is one of the first steps towards a host infection. They represent interesting objects for proteomic studies because of the presence of unique proteins with unexplored biotechnological potential required for pathogen viability, development and the subsequent host infection. Proteomic peculiarities of survival structures of different fungi, including those of biotechnological significance (e.g., Asperillus fumigatus, A. nidulans, Metarhizium anisopliae), in a dormant state, as well as changes in the protein production during early stages of fungal development are the subjects of the present review. We focused on biological aspects of proteomic studies of fungal survival structures rather than on an evaluation of proteomic approaches. For that reason, proteins that have been identified in this context are discussed from the point of view of their involvement in different biological processes and possible functions assigned to them. This is the first review paper summarizing recent advances in proteomics of fungal survival structures. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Helicobacter pylori: a poor man's gut pathogen?

    Directory of Open Access Journals (Sweden)

    Khalifa Mohammed

    2010-03-01

    Full Text Available Abstract Helicobacter pylori is one of the human pathogens with highest prevalence around the world; yet, its principal mode of transmission remains largely unknown. The role of H. pylori in gastric disease and cancer has not been established until the end of the 20th century. Since then, its epidemiology has been extensively studied, and an accruing body of literature suggests that not all humans are equally at risk of infection by this gut pathogen. Here, we briefly review the different epidemiological aspects of H. pylori infection with emphasis on those factors related to human poverty. The epidemiology of H. pylori infection is characterized by marked differences between developing and developed countries, notably among children. In addition, congruent lines of evidence point out to socioeconomic factors and living standards as main determinants of the age-dependent acquisition rate of H. pylori, and consequently its prevalence. These data are alarming in the light of the changing global climate and birth rate, which are expected to change the demography of our planet, putting more children at risk of H. pylori and its complications for years to come.

  10. Vibrio parahaemolyticus- An emerging foodborne pathogen

    Directory of Open Access Journals (Sweden)

    S Nelapati

    2012-02-01

    Full Text Available Vibrio parahaemolyticus is a halophilic gram negative, motile, oxidase positive, straight or curved rod-shaped, facultative anaerobic bacteria that occur naturally in the marine environment. They form part of the indigenous microflora of aquatic habitats of various salinity and are the major causative agents for some of the most serious diseases in fish, shellfish and penacid shrimp. This human pathogen causes acute gastroenteritis characterized by diarrhea, vomiting and abdominal cramps through consumption of contaminated raw fish or shellfish. V. parahaemolyticus is the leading cause of gastroenteritis due to the consumption of seafood worldwide. The incidence of V. parahaemolyticus infection has been increasing in many parts of the world, due to the emergence of O3:K6 serotype carrying the tdh gene which is responsible for most outbreaks worldwide. The pathogenicity of this organism is closely correlated with the Kanagawa phenomenon (KP + due to production of Kanagawa hemolysin or the thermostable direct hemolysin (TDH. The TDH and TRH (TDH-related hemolysin encoded by tdh and trh genes are considered to be important virulence factors. [Vet. World 2012; 5(1.000: 48-63

  11. Fusarium species as pathogen on orchids.

    Science.gov (United States)

    Srivastava, Shikha; Kadooka, Chris; Uchida, Janice Y

    2018-03-01

    The recent surge in demand for exotic ornamental crops such as orchids has led to a rise in international production, and a sharp increase in the number of plant and plant products moving between countries. Along with the plants, diseases are also being transported and introduced into new areas. Fusarium is one of the major diseases causing pathogens infecting orchids that is spreading through international trade. Studies have identified several species of Fusarium associated with orchids, some are pathogenic and cause symptoms such as leaf and flower spots, leaf or sheath blights, pseudostem or root rots, and wilts. Infection and damage caused by Fusarium reduces the quality of plants and flowers, and can cause severe economic losses. This review documents the current status of the Fusarium-orchid interaction, and illustrates challenges and future perspectives based on the available literature. This review is the first of Fusarium and orchid interactions, and integrates diverse results that both furthers the understanding and knowledge of this disease complex, and will enable the development of effective disease management practices. Copyright © 2017 Elsevier GmbH. All rights reserved.

  12. Bacterial pathogens in a reactor cooling reservoir

    International Nuclear Information System (INIS)

    Kasweck, K.L.; Fliermans, C.B.

    1978-01-01

    The results of the sampling in both Par Pond and Clark Hill Reservoir are given. The frequency of isolation is a qualitative parameter which indicates how often the specified bacterium was isolated from each habitat. Initial scoping experiments demonstrated that a wider variety of pathogenic bacteria occur in Par Pond than in Clark Hill Reservoir. Such findings are interesting because Par Pond does not receive any human wastes directly, yet bacteria generally associated with human wastes are more frequently isolated from Par Pond. Previous studies have demonstrated that certain non-spore-forming enteric bacteria do not survive the intense heat associated with the cooling water when the reactor is operating. However, even when the reactor is not operating, cooling water, consisting of 10% makeup water from Savannah River, continues to flow into Par Pond. This flow provides a source of bacteria which inoculate Par Pond. Once the reactor is again operating, these same bacteria appear to be able to survive and grow within the Par Pond system. Thus, Par Pond and the associated lakes and canals of the Par Pond system provide a pool of pathogens that normally would not survive in natural waters

  13. Hybrid histidine kinases in pathogenic fungi.

    Science.gov (United States)

    Defosse, Tatiana A; Sharma, Anupam; Mondal, Alok K; Dugé de Bernonville, Thomas; Latgé, Jean-Paul; Calderone, Richard; Giglioli-Guivarc'h, Nathalie; Courdavault, Vincent; Clastre, Marc; Papon, Nicolas

    2015-03-01

    Histidine kinases (HK) sense and transduce via phosphorylation events many intra- and extracellular signals in bacteria, archaea, slime moulds and plants. HK are also widespread in the fungal kingdom, but their precise roles in the regulation of physiological processes remain largely obscure. Expanding genomic resources have recently given the opportunity to identify uncharacterised HK family members in yeasts and moulds and now allow proposing a complex classification of Basidiomycota, Ascomycota and lower fungi HK. A growing number of genetic approaches have progressively provided new insight into the role of several groups of HK in prominent fungal pathogens. In particular, a series of studies have revealed that members of group III HK, which occur in the highest number of fungal species and contain a unique N-terminus region consisting of multiple HAMP domain repeats, regulate morphogenesis and virulence in various human, plant and insect pathogenic fungi. This research field is further supported by recent shape-function studies providing clear correlation between structural properties and signalling states in group III HK. Since HK are absent in mammals, these represent interesting fungal target for the discovery of new antifungal drugs. © 2015 John Wiley & Sons Ltd.

  14. Burkholderia glumae: next major pathogen of rice?

    Science.gov (United States)

    Ham, Jong Hyun; Melanson, Rebecca A; Rush, Milton C

    2011-05-01

    Burkholderia glumae causes bacterial panicle blight of rice, which is an increasingly important disease problem in global rice production. Toxoflavin and lipase are known to be major virulence factors of this pathogen, and their production is dependent on the TofI/TofR quorum-sensing system, which is mediated by N-octanoyl homoserine lactone. Flagellar biogenesis and a type III secretion system are also required for full virulence of B. glumae. Bacterial panicle blight is thought to be caused by seed-borne B. glumae; however, its disease cycle is not fully understood. In spite of its economic importance, neither effective control measures for bacterial panicle blight nor rice varieties showing complete resistance to the disease are currently available. A better understanding of the molecular mechanisms underlying B. glumae virulence and of the rice defence mechanisms against the pathogen would lead to the development of better methods of disease control for bacterial panicle blight. Bacteria; Proteobacteria; Betaproteobacteria; Burkholderiales; Burkholderiaceae; Burkholderia. Gram-negative, capsulated, motile, lophotrichous flagella, pectolytic. Aborted seed, empty grains as a result of failure of grain filling, brown spots on panicles, seedling rot. Seed sterilization, planting partially resistant lines (no completely resistant line is available). KNOWN VIRULENCE FACTORS: Toxoflavin, lipase, type III effectors. © 2010 LSU AGCENTER. MOLECULAR PLANT PATHOLOGY © 2010 BSPP AND BLACKWELL PUBLISHING LTD.

  15. Pathogenicity of two Egyptian H5N1 highly pathogenic avian influenza viruses in domestic ducks.

    Science.gov (United States)

    Wasilenko, J L; Arafa, A M; Selim, A A; Hassan, M K; Aly, M M; Ali, A; Nassif, S; Elebiary, E; Balish, A; Klimov, A; Suarez, D L; Swayne, D E; Pantin-Jackwood, M J

    2011-01-01

    Domestic ducks have been implicated in the dissemination and evolution of H5N1 highly pathogenic avian influenza (HPAI) viruses. In this study, two H5N1 HPAI viruses belonging to clade 2.2.1 isolated in Egypt in 2007 and 2008 were analyzed for their pathogenicity in domestic Pekin ducks. Both viruses produced clinical signs and mortality, but the 2008 virus was more virulent, inducing early onset of neurological signs and killing all ducks with a mean death time (MDT) of 4.1 days. The 2007 virus killed 3/8 ducks with a MDT of 7 days. Full-genome sequencing and phylogenetic analysis were used to examine differences in the virus genes that might explain the differences observed in pathogenicity. The genomes differed in 49 amino acids, with most of the differences found in the hemagglutinin protein. This increase in pathogenicity in ducks observed with certain H5N1 HPAI viruses has implications for the control of the disease, since vaccinated ducks infected with highly virulent strains shed viruses for longer periods of time, perpetuating the virus in the environment and increasing the possibility of transmission to susceptible birds.

  16. Yeast cell differentiation: Lessons from pathogenic and non-pathogenic yeasts

    Czech Academy of Sciences Publication Activity Database

    Pálková, Z.; Váchová, Libuše

    2016-01-01

    Roč. 57, SEP (2016), s. 110-119 ISSN 1084-9521 R&D Projects: GA ČR GA13-08605S; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 Keywords : Pathogenic yeasts * Biofilms and colonies * Cell differentiation Subject RIV: EE - Microbiology, Virology Impact factor: 6.614, year: 2016

  17. Effect of electron beam irradiation on pathogenicity and pathogenic enzyme activity of botrytis cinerea

    International Nuclear Information System (INIS)

    Chen Zhaoliang; Wang Haihong; Qiao Yongjin

    2013-01-01

    In order to define the effect of electron beam irradiation on pathogenicity of Botrytis cinerea mycelia, the disease parameters of strawberry fruits inoculated with mycelia of B. cinerea irradiated by electron beam with different dose were tested in vivo, the production and activity of pectinase and cellulase secreted by B. cinerea irradiated by electron beam were also tested by DNS method. The results showed that pathogenicity of irradiated B. cinerea decreased significantly. The disease incidence and disease index of strawberry inoculated by irradiated B. cinerea after 3 days and 5 days was only 15.00% and 11.39 compared to control (91.67% and 77.78), respectively. The activity of pectinase and cellulase of B. cinerea irradiated by electron beam with above 2.0 kGy were inhibited obviously. The activity of PMG of irradiated B. cinerea decreased by 37.65% and 57.46% compared with control 3 days and 5 days cultured at 20℃, and the activity of CX and BG decreased by over 60% than that of control. The hardness of strawberry treated by enzyme solution which producted by B. cinerea irradiated by electron beam at 2.0 kGy was higher than that of control strawberry and it mainted disease resistance well. Electron beam can inhibited the pathogenic enzyme activity and pathogenicity of B. cinerea obviously. So it can control gray mold of postharvest strawberry effectively. (authors)

  18. Pathogenicity in POLG syndromes: DNA polymerase gamma pathogenicity prediction server and database.

    Science.gov (United States)

    Nurminen, Anssi; Farnum, Gregory A; Kaguni, Laurie S

    2017-06-01

    DNA polymerase gamma (POLG) is the replicative polymerase responsible for maintaining mitochondrial DNA (mtDNA). Disorders related to its functionality are a major cause of mitochondrial disease. The clinical spectrum of POLG syndromes includes Alpers-Huttenlocher syndrome (AHS), childhood myocerebrohepatopathy spectrum (MCHS), myoclonic epilepsy myopathy sensory ataxia (MEMSA), the ataxia neuropathy spectrum (ANS) and progressive external ophthalmoplegia (PEO). We have collected all publicly available POLG-related patient data and analyzed it using our pathogenic clustering model to provide a new research and clinical tool in the form of an online server. The server evaluates the pathogenicity of both previously reported and novel mutations. There are currently 176 unique point mutations reported and found in mitochondrial patients in the gene encoding the catalytic subunit of POLG, POLG . The mutations are distributed nearly uniformly along the length of the primary amino acid sequence of the gene. Our analysis shows that most of the mutations are recessive, and that the reported dominant mutations cluster within the polymerase active site in the tertiary structure of the POLG enzyme. The POLG Pathogenicity Prediction Server (http://polg.bmb.msu.edu) is targeted at clinicians and scientists studying POLG disorders, and aims to provide the most current available information regarding the pathogenicity of POLG mutations.

  19. Prediction of molecular mimicry candidates in human pathogenic bacteria.

    Science.gov (United States)

    Doxey, Andrew C; McConkey, Brendan J

    2013-08-15

    Molecular mimicry of host proteins is a common strategy adopted by bacterial pathogens to interfere with and exploit host processes. Despite the availability of pathogen genomes, few studies have attempted to predict virulence-associated mimicry relationships directly from genomic sequences. Here, we analyzed the proteomes of 62 pathogenic and 66 non-pathogenic bacterial species, and screened for the top pathogen-specific or pathogen-enriched sequence similarities to human proteins. The screen identified approximately 100 potential mimicry relationships including well-characterized examples among the top-scoring hits (e.g., RalF, internalin, yopH, and others), with about 1/3 of predicted relationships supported by existing literature. Examination of homology to virulence factors, statistically enriched functions, and comparison with literature indicated that the detected mimics target key host structures (e.g., extracellular matrix, ECM) and pathways (e.g., cell adhesion, lipid metabolism, and immune signaling). The top-scoring and most widespread mimicry pattern detected among pathogens consisted of elevated sequence similarities to ECM proteins including collagens and leucine-rich repeat proteins. Unexpectedly, analysis of the pathogen counterparts of these proteins revealed that they have evolved independently in different species of bacterial pathogens from separate repeat amplifications. Thus, our analysis provides evidence for two classes of mimics: complex proteins such as enzymes that have been acquired by eukaryote-to-pathogen horizontal transfer, and simpler repeat proteins that have independently evolved to mimic the host ECM. Ultimately, computational detection of pathogen-specific and pathogen-enriched similarities to host proteins provides insights into potentially novel mimicry-mediated virulence mechanisms of pathogenic bacteria.

  20. Transport and fate of microbial pathogens in agricultural settings

    Science.gov (United States)

    Bradford, Scott A.; Morales, Veronica L.; Zhang, Wei; Harvey, Ronald W.; Packman, Aaron I.; Mohanram, Arvind; Welty, Claire

    2013-01-01

    An understanding of the transport and survival of microbial pathogens (pathogens hereafter) in agricultural settings is needed to assess the risk of pathogen contamination to water and food resources, and to develop control strategies and treatment options. However, many knowledge gaps still remain in predicting the fate and transport of pathogens in runoff water, and then through the shallow vadose zone and groundwater. A number of transport pathways, processes, factors, and mathematical models often are needed to describe pathogen fate in agricultural settings. The level of complexity is dramatically enhanced by soil heterogeneity, as well as by temporal variability in temperature, water inputs, and pathogen sources. There is substantial variability in pathogen migration pathways, leading to changes in the dominant processes that control pathogen transport over different spatial and temporal scales. For example, intense rainfall events can generate runoff and preferential flow that can rapidly transport pathogens. Pathogens that survive for extended periods of time have a greatly enhanced probability of remaining viable when subjected to such rapid-transport events. Conversely, in dry seasons, pathogen transport depends more strongly on retention at diverse environmental surfaces controlled by a multitude of coupled physical, chemical, and microbiological factors. These interactions are incompletely characterized, leading to a lack of consensus on the proper mathematical framework to model pathogen transport even at the column scale. In addition, little is known about how to quantify transport and survival parameters at the scale of agricultural fields or watersheds. This review summarizes current conceptual and quantitative models for pathogen transport and fate in agricultural settings over a wide range of spatial and temporal scales. The authors also discuss the benefits that can be realized by improved modeling, and potential treatments to mitigate the risk

  1. A new oligonucleotide microarray for detection of pathogenic and non-pathogenic Legionella spp.

    Directory of Open Access Journals (Sweden)

    Boyang Cao

    Full Text Available Legionella pneumophila has been recognized as the major cause of legionellosis since the discovery of the deadly disease. Legionella spp. other than L. pneumophila were later found to be responsible to many non-pneumophila infections. The non-L. pneumophila infections are likely under-detected because of a lack of effective diagnosis. In this report, we have sequenced the 16S-23S rRNA gene internal transcribed spacer (ITS of 10 Legionella species and subspecies, including L. anisa, L. bozemanii, L. dumoffii, L. fairfieldensis, L. gormanii, L. jordanis, L. maceachernii, L. micdadei, L. pneumophila subspp. fraseri and L. pneumophila subspp. pasculleii, and developed a rapid oligonucleotide microarray detection technique accordingly to identify 12 most common Legionella spp., which consist of 11 pathogenic species of L. anisa, L. bozemanii, L. dumoffii, L. gormanii, L. jordanis, L. longbeachae, L. maceachernii, L. micdadei, and L. pneumophila (including subspp. pneumophila, subspp. fraseri, and subspp. pasculleii and one non-pathogenic species, L. fairfieldensis. Twenty-nine probes that reproducibly detected multiple Legionella species with high specificity were included in the array. A total of 52 strains, including 30 target pathogens and 22 non-target bacteria, were used to verify the oligonucleotide microarray assay. The sensitivity of the detection was at 1.0 ng with genomic DNA or 13 CFU/100 mL with Legionella cultures. The microarray detected seven samples of air conditioner-condensed water with 100% accuracy, validating the technique as a promising method for applications in basic microbiology, clinical diagnosis, food safety, and epidemiological surveillance. The phylogenetic study based on the ITS has also revealed that the non-pathogenic L. fairfieldensis is the closest to L. pneumophila than the nine other pathogenic Legionella spp.

  2. Pathogen metadata platform: software for accessing and analyzing pathogen strain information.

    Science.gov (United States)

    Chang, Wenling E; Peterson, Matthew W; Garay, Christopher D; Korves, Tonia

    2016-09-15

    Pathogen metadata includes information about where and when a pathogen was collected and the type of environment it came from. Along with genomic nucleotide sequence data, this metadata is growing rapidly and becoming a valuable resource not only for research but for biosurveillance and public health. However, current freely available tools for analyzing this data are geared towards bioinformaticians and/or do not provide summaries and visualizations needed to readily interpret results. We designed a platform to easily access and summarize data about pathogen samples. The software includes a PostgreSQL database that captures metadata useful for disease outbreak investigations, and scripts for downloading and parsing data from NCBI BioSample and BioProject into the database. The software provides a user interface to query metadata and obtain standardized results in an exportable, tab-delimited format. To visually summarize results, the user interface provides a 2D histogram for user-selected metadata types and mapping of geolocated entries. The software is built on the LabKey data platform, an open-source data management platform, which enables developers to add functionalities. We demonstrate the use of the software in querying for a pathogen serovar and for genome sequence identifiers. This software enables users to create a local database for pathogen metadata, populate it with data from NCBI, easily query the data, and obtain visual summaries. Some of the components, such as the database, are modular and can be incorporated into other data platforms. The source code is freely available for download at https://github.com/wchangmitre/bioattribution .

  3. Comparative genomics reveals mobile pathogenicity chromosomes in Fusarium

    Science.gov (United States)

    Ma, Li-Jun; van der Does, H. Charlotte; Borkovich, Katherine A.; Coleman, Jeffrey J.; Daboussi, Marie-Josée; Di Pietro, Antonio; Dufresne, Marie; Freitag, Michael; Grabherr, Manfred; Henrissat, Bernard; Houterman, Petra M.; Kang, Seogchan; Shim, Won-Bo; Woloshuk, Charles; Xie, Xiaohui; Xu, Jin-Rong; Antoniw, John; Baker, Scott E.; Bluhm, Burton H.; Breakspear, Andrew; Brown, Daren W.; Butchko, Robert A. E.; Chapman, Sinead; Coulson, Richard; Coutinho, Pedro M.; Danchin, Etienne G. J.; Diener, Andrew; Gale, Liane R.; Gardiner, Donald M.; Goff, Stephen; Hammond-Kosack, Kim E.; Hilburn, Karen; Hua-Van, Aurélie; Jonkers, Wilfried; Kazan, Kemal; Kodira, Chinnappa D.; Koehrsen, Michael; Kumar, Lokesh; Lee, Yong-Hwan; Li, Liande; Manners, John M.; Miranda-Saavedra, Diego; Mukherjee, Mala; Park, Gyungsoon; Park, Jongsun; Park, Sook-Young; Proctor, Robert H.; Regev, Aviv; Ruiz-Roldan, M. Carmen; Sain, Divya; Sakthikumar, Sharadha; Sykes, Sean; Schwartz, David C.; Turgeon, B. Gillian; Wapinski, Ilan; Yoder, Olen; Young, Sarah; Zeng, Qiandong; Zhou, Shiguo; Galagan, James; Cuomo, Christina A.; Kistler, H. Corby; Rep, Martijn

    2011-01-01

    Fusarium species are among the most important phytopathogenic and toxigenic fungi. To understand the molecular underpinnings of pathogenicity in the genus Fusarium, we compared the genomes of three phenotypically diverse species: Fusarium graminearum, Fusarium verticillioides and Fusarium oxysporum f. sp. lycopersici. Our analysis revealed lineage-specific (LS) genomic regions in F. oxysporum that include four entire chromosomes and account for more than one-quarter of the genome. LS regions are rich in transposons and genes with distinct evolutionary profiles but related to pathogenicity, indicative of horizontal acquisition. Experimentally, we demonstrate the transfer of two LS chromosomes between strains of F. oxysporum, converting a non-pathogenic strain into a pathogen. Transfer of LS chromosomes between otherwise genetically isolated strains explains the polyphyletic origin of host specificity and the emergence of new pathogenic lineages in F. oxysporum. These findings put the evolution of fungal pathogenicity into a new perspective. PMID:20237561

  4. Atypical pathogen infection in community-acquired pneumonia.

    Science.gov (United States)

    Yu, Yun; Fei, Aihua

    2016-02-01

    Community-acquired pneumonia (CAP) is a world wide cause of morbidity and mortality. The etiology of CAP is different between countries and changes over time. With the increasing incidence, atypical pathogens are attracting more and more attention all over the world. In many countries, atypical pathogens are one of the main pathogens of CAP, and even could be the most prevalent etiology in China. Atypical pathogen infections can cause multi-system complications, which leads to a worse prognosis. Although still controversial, empirical antibiotic coverage of atypical pathogens in CAP may improve outcomes, shorten length of hospitalization, reduce mortality and lower total hospitalization costs. The macrolide resistance rate of atypical pathogens, especially Mycoplasma Pneumoniae (M. Pneumoniae) is high, so fluoroquinolones or tetracyclines should be considered as alternative therapy.

  5. Opportunistic respiratory pathogens in the oral cavity of the elderly.

    Science.gov (United States)

    Tada, Akio; Hanada, Nobuhiro

    2010-10-01

    The oral cavity of the hospitalized or bedridden elderly is often a reservoir for opportunistic pathogens associated with respiratory diseases. Commensal flora and the host interact in a balanced fashion and oral infections are considered to appear following an imbalance in the oral resident microbiota, leading to the emergence of potentially pathogenic bacteria. The definition of the process involved in colonization by opportunistic respiratory pathogens needs to elucidate the factors responsible for the transition of the microbiota from commensal to pathogenic flora. The regulatory factors influencing the oral ecosystem can be divided into three major categories: the host defense system, commensal bacteria, and external pathogens. In this article, we review the profile of these categories including the intricate cellular interaction between immune factors and commensal bacteria and the disturbance in homeostasis in the oral cavity of hospitalized or bedridden elderly, which facilitates oral colonization by opportunistic respiratory pathogens. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  6. Pseudomnas syringae – a Pathogen of Fruit Trees in Serbia

    Directory of Open Access Journals (Sweden)

    Veljko Gavrilović

    2009-01-01

    Full Text Available Data about symptomatology, pathogenicity and bacteriological characteristics of Pseudomonas syringae, and PCR methods for fast and reliable detection of the pathogen are given in this paper. P. syringae has been experimentaly proved as a pathogen of pear, apple, apricot, plum cherry, and raspberry, and pathogen strains have also been isolated from necrotic peach buds. Two pathogen varieties, syringae and morsprunorum, were found in our research in Serbia, the former being dominant on fruit trees.The most reliable method for detection of this bacteria is PCR, using BOX and REP primers. This method has also revealed significant differences among the strains originating from fruit trees in Serbia. Thus, it was proved that the population of P. syringae in Serbia is heterogeneous, which is very important for future epidemiologocal studies. Control of this pathogen includes mechanical, cultural and chemical measures, but integrated approach is very important for sustainable control.

  7. Pathogen refuge: a key to understanding biological control.

    Science.gov (United States)

    Johnson, Kenneth B

    2010-01-01

    Pathogen refuge is the idea that some potentially infectious pathogen propagules are not susceptible to the influence of an antagonistic microbial agent. The existence of a refuge can be attributable to one or more factors, including temporal, spatial, structural, and probabilistic, or to the pathogen's evolved ability to acquire antagonist-free space prior to ingress into a plant host. Within a specific pathosystem, refuge size can be estimated in experiments by measuring the proportion of pathogen propagules that remain infective as a function of the amount of antagonist introduced to the system. Refuge size is influenced by qualities of specific antagonists and by environment but less so by the quantity of antagonist. Consequently, most efforts to improve and optimize biological control are in essence efforts to reduce refuge size. Antagonist mixtures, optimal timing of antagonist introductions, integrated biological and chemical control, environmental optimization, and the utilization of disarmed pathogens as antagonists are strategies with potential to minimize a pathogen refuge.

  8. Subversion of inflammasome activation and pyroptosis by pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Larissa D Cunha

    2013-11-01

    Full Text Available Activation of the inflammasome occurs in response to a notably high number of pathogenic microbes and is a broad innate immune response that effectively contributes to restriction of pathogen replication and generation of adaptive immunity. Activation of these platforms leads to caspase-1- and/or caspase-11-dependent secretion of proteins, including cytokines, and induction of a specific form of cell death called pyroptosis, which directly or indirectly contribute for restriction of pathogen replication. Not surprisingly, bona fide intracellular pathogens developed strategies for manipulation of cell death to guarantee intracellular replication. In this sense, the remarkable advances in the knowledge of the inflammasome field have been accompanied by several reports characterizing the inhibition of this platform by several pathogenic bacteria. Herein, we review some processes used by pathogenic bacteria, including Yersinia spp., Pseudomonas aeruginosa, Vibrio parahaemolyticus, Chlamydia trachomatis, Francisella tularensis, Shigella flexneri, Legionella pneumophila and Coxiella burnetii to evade the activation of the inflammasome and the induction of pyroptosis.

  9. Social barriers to pathogen transmission in wild animal populations

    Energy Technology Data Exchange (ETDEWEB)

    Loehle, C.

    1995-03-01

    Diseases and pathogens are receiving increasing recognition as sources of mortality in animal populations. Immune system strength is clearly important in fending off pathogen attack. Physical barriers to pathogen entry are also important. Various individual behaviors are efficacious in reducing contact with diseases and pests. This paper focuses on a fourth mode of defense: social barriers to transmission. Various social behaviors have pathogen transmission consequences. Selective pressures on these social behaviors may therefore exist. Effects on pathogen transmission of mating strategies, social avoidance, group size, group isolation, and other behaviors are explored. It is concluded that many of these behaviors may have been affected by selection pressures to reduce transmission of pathogens. 84 refs., 1 tab.

  10. Subversion of inflammasome activation and pyroptosis by pathogenic bacteria.

    Science.gov (United States)

    Cunha, Larissa D; Zamboni, Dario S

    2013-01-01

    Activation of the inflammasome occurs in response to a notably high number of pathogenic microbes and is a broad innate immune response that effectively contributes to restriction of pathogen replication and generation of adaptive immunity. Activation of these platforms leads to caspase-1- and/or caspase-11-dependent secretion of proteins, including cytokines, and induction of a specific form of cell death called pyroptosis, which directly or indirectly contribute for restriction of pathogen replication. Not surprisingly, bona fide intracellular pathogens developed strategies for manipulation of cell death to guarantee intracellular replication. In this sense, the remarkable advances in the knowledge of the inflammasome field have been accompanied by several reports characterizing the inhibition of this platform by several pathogenic bacteria. Herein, we review some processes used by pathogenic bacteria, including Yersinia spp., Pseudomonas aeruginosa, Vibrio parahaemolyticus, Chlamydia trachomatis, Francisella tularensis, Shigella flexneri, Legionella pneumophila, and Coxiella burnetii to evade the activation of the inflammasome and the induction of pyroptosis.

  11. Porphyromonas gingivalis: Major Periodontopathic Pathogen Overview

    Science.gov (United States)

    Mysak, Jaroslav; Podzimek, Stepan; Sommerova, Pavla; Lyuya-Mi, Yelena; Bartova, Jirina; Janatova, Tatjana; Prochazkova, Jarmila; Duskova, Jana

    2014-01-01

    Porphyromonas gingivalis is a Gram-negative oral anaerobe that is involved in the pathogenesis of periodontitis and is a member of more than 500 bacterial species that live in the oral cavity. This anaerobic bacterium is a natural member of the oral microbiome, yet it can become highly destructive (termed pathobiont) and proliferate to high cell numbers in periodontal lesions: this is attributed to its arsenal of specialized virulence factors. The purpose of this review is to provide an overview of one of the main periodontal pathogens—Porphyromonas gingivalis. This bacterium, along with Treponema denticola and Tannerella forsythia, constitute the “red complex,” a prototype polybacterial pathogenic consortium in periodontitis. This review outlines Porphyromonas gingivalis structure, its metabolism, its ability to colonize the epithelial cells, and its influence upon the host immunity. PMID:24741603

  12. Porphyromonas gingivalis: Major Periodontopathic Pathogen Overview

    Directory of Open Access Journals (Sweden)

    Jaroslav Mysak

    2014-01-01

    Full Text Available Porphyromonas gingivalis is a Gram-negative oral anaerobe that is involved in the pathogenesis of periodontitis and is a member of more than 500 bacterial species that live in the oral cavity. This anaerobic bacterium is a natural member of the oral microbiome, yet it can become highly destructive (termed pathobiont and proliferate to high cell numbers in periodontal lesions: this is attributed to its arsenal of specialized virulence factors. The purpose of this review is to provide an overview of one of the main periodontal pathogens—Porphyromonas gingivalis. This bacterium, along with Treponema denticola and Tannerella forsythia, constitute the “red complex,” a prototype polybacterial pathogenic consortium in periodontitis. This review outlines Porphyromonas gingivalis structure, its metabolism, its ability to colonize the epithelial cells, and its influence upon the host immunity.

  13. Specialized Pathogen of a Social Insect

    DEFF Research Database (Denmark)

    Małagocka, Joanna

    Entomopathogenic fungi from the order Entomophthorales are highly specialized, host-specific and obligatory pathogens, which infect, consume and eventually kill their host insect within a few days. Established infection can effectively wipe out the majority of a host population. Social insects......, on the other hand, are remarkably efficient at preventing disease, a trait which necessarily arose together with social organization. In the one known example of social insects, in this case wood ants of the genus Formica, being attacked by an entomophthoralean fungus – Pandora formicae, social behaviors......, various aspects of the interaction with a social insect host are studied. Like a number of other entomophthoralean fungi, P. formicae manipulates pre-death behavior of its host to secure favorable position for transmission of actively discharged conidia to new hosts. Before dying, infected ants climb...

  14. Pathogens in Ornamental Waters: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Maria Nascimento

    2016-02-01

    Full Text Available In parks, ornamental waters of easy access and populated with animals are quite attractive to children and yet might hide threats to human health. The present work focuses on the microbiota of the ornamental waters of a Lisboa park, characterized during 2015. The results show a dynamic microbiota integrating human pathogens such as Klebsiella pneumoniae, Aeromonas spp. and Enterobacter spp., and also antibiotic resistant bacteria. K. pneumoniae and Aeromonas spp. were present as planktonic and biofilm organized bacteria. In vitro K. pneumoniae and Aeromonas spp. showed an enhanced ability to assemble biofilm at 25 °C than at 37 °C. Bacteria recovered from biofilm samples showed an increased antibiotic resistance compared to the respective planktonic counterparts.

  15. Infection strategies of enteric pathogenic Escherichia coli.

    Science.gov (United States)

    Clements, Abigail; Young, Joanna C; Constantinou, Nicholas; Frankel, Gad

    2012-01-01

    Enteric Escherichia coli (E. coli) are both natural flora of humans and important pathogens causing significant morbidity and mortality worldwide. Traditionally enteric E. coli have been divided into 6 pathotypes, with further pathotypes often proposed. In this review we suggest expansion of the enteric E. coli into 8 pathotypes to include the emerging pathotypes of adherent invasive E. coli (AIEC) and Shiga-toxin producing enteroaggregative E. coli (STEAEC). The molecular mechanisms that allow enteric E. coli to colonize and cause disease in the human host are examined and for two of the pathotypes that express a type 3 secretion system (T3SS) we discuss the complex interplay between translocated effectors and manipulation of host cell signaling pathways that occurs during infection.

  16. Separation of pathogenic bacteria by chain length.

    Science.gov (United States)

    Beech, Jason P; Ho, Bao Dang; Garriss, Geneviève; Oliveira, Vitor; Henriques-Normark, Birgitta; Tegenfeldt, Jonas O

    2018-02-13

    Using Deterministic Lateral Displacement devices optimized for sensitivity to particle length, we separate subpopulations of bacteria depending on known properties that affect their capability to cause disease (virulence). For the human bacterial pathogen Streptococcus pneumoniae, bacterial chain length and the presence of a capsule are known virulence factors contributing to its ability to cause severe disease. Separation of cultured pneumococci into subpopulations based on morphological type (single cocci, diplococci and chains) will enable more detailed studies of the role they play in virulence. Moreover, we present separation of mixed populations of almost genetically identical encapsulated and non-encapsulated pneumococcal strains in our device. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  17. Microbial and viral pathogens in colorectal cancer.

    LENUS (Irish Health Repository)

    Collins, Danielle

    2011-05-01

    The heterogenetic and sporadic nature of colorectal cancer has led to many epidemiological associations with causes of this disease. As our understanding of the underlying molecular processes in colorectal-cancer develops, the concept of microbial-epithelial interactions as an oncogenic trigger might provide a plausible hypothesis for the pathogenesis of colorectal cancer. By contrast with other cancers of the gastrointestinal tract (gastric carcinoma, mucosa-associated lymphoid-tissue lymphoma), a direct causal link between microbial infection (bacteria and viruses) and colorectal carcinoma has not been established. Studies support the involvement of these organisms in oncogenesis, however, in colorectal cancer, clinical data are lacking. Here, we discuss current evidence (both in vitro and clinical studies), and focus on a putative role for bacterial and viral pathogens as a cause of colorectal cancer.

  18. Microbial and viral pathogens in colorectal cancer.

    LENUS (Irish Health Repository)

    Collins, Danielle

    2012-02-01

    The heterogenetic and sporadic nature of colorectal cancer has led to many epidemiological associations with causes of this disease. As our understanding of the underlying molecular processes in colorectal-cancer develops, the concept of microbial-epithelial interactions as an oncogenic trigger might provide a plausible hypothesis for the pathogenesis of colorectal cancer. By contrast with other cancers of the gastrointestinal tract (gastric carcinoma, mucosa-associated lymphoid-tissue lymphoma), a direct causal link between microbial infection (bacteria and viruses) and colorectal carcinoma has not been established. Studies support the involvement of these organisms in oncogenesis, however, in colorectal cancer, clinical data are lacking. Here, we discuss current evidence (both in vitro and clinical studies), and focus on a putative role for bacterial and viral pathogens as a cause of colorectal cancer.

  19. Algodystrophy: recent insight into the pathogenic framework.

    Science.gov (United States)

    Varenna, Massimo; Zucchi, Francesca

    2015-01-01

    Algodystrophy, nowadays called CRPS I, is a painful syndrome characterized by sensory and vasomotor disturbance, edema and functional impairment. Significant progress in knowledge about the pathogenic mechanisms of the disease have been recently achieved, but they are not yet fully understood and some clinical aspects are still lacking of a whole pathogenetic comprehension. The local release of pro-inflammatory neuropeptides and some cytokines may be the event that triggers and maintains the disease, causing hyperalgesia and allodynia. In the following phases, the impaired capillary permeability, the interstitial edema and the consequent hypoxia and local acidosis have been proposed as possible pathophysiological pathways. The local hyperactivity of the sympathetic nervous system supposed in the past has not be confirmed and the hypothesis of an altered nociceptive processing at CNS level has limited evidences in acute phases of the disease. The steady bone involvement could be confirmed by the efficacy of bisphosphonates in the treatment of early disease.

  20. WHEAT PATHOGEN RESISTANCE AND CHITINASE PROFILE

    Directory of Open Access Journals (Sweden)

    Zuzana Gregorová

    2015-02-01

    Full Text Available The powdery mildew and leaf rust caused by Blumeria graminis and Puccinia recondita (respectively are common diseases of wheat throughout the world. These fungal diseases greatly affect crop productivity. Incorporation of effective and durable disease resistance is an important breeding objective for wheat improvement. We have evaluated resistance of four bread wheat (Triticum aestivum and four spelt wheat (Triticum spelta cultivars. Chitinases occurrence as well as their activity was determined in leaf tissues. There was no correlation between resistance rating and activity of chitinase. The pattern of chitinases reveals four isoforms with different size in eight wheat cultivars. A detailed understanding of the molecular events that take place during a plant–pathogen interaction is an essential goal for disease control in the future.

  1. Campylobacter ureolyticus: an emerging gastrointestinal pathogen?

    Science.gov (United States)

    Bullman, Susan; Corcoran, Daniel; O'Leary, James; Lucey, Brigid; Byrne, Deirdre; Sleator, Roy D

    2011-03-01

    A total of 7194 faecal samples collected over a 1-year period from patients presenting with diarrhoea were screened for Campylobacter spp. using EntericBio(®) , a multiplex-PCR system. Of 349 Campylobacter-positive samples, 23.8% were shown to be Campylobacter ureolyticus, using a combination of 16S rRNA gene analysis and highly specific primers targeting the HSP60 gene of this organism. This is, to the best of our knowledge, the first report of C. ureolyticus in the faeces of patients presenting with gastroenteritis and may suggest a role for this organism as an emerging enteric pathogen. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  2. Shellfish as reservoirs of bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Harry Hariharan

    2016-04-01

    Full Text Available The objective of this article is to present an overview on bacterial pathogens associated with shellfish in Grenada and other countries including the authors’ experience. Although there have been considerable published work on vibrios, there is a lack of information on Salmonella serovars associated with various shellfish. In Grenada, for instance the blue land crabs collected from their habitats were found to harbor several Salmonella serovars. Also, it is notable that only minimal research has been done on shellfish such as conchs and whelks, which are common in the Caribbean and West Indies. Information on anaerobic bacteria, particularly, non-spore forming bacteria associated with shellfish, in general, is also scanty. This review re-examines this globally important topic based on the recent findings as well as past observations. Strategies for reduction of bacteria in oysters are briefly mentioned because of the fact that oysters are consumed commonly without complete cooking.

  3. Fusobacterium nucleatum: a commensal-turned pathogen.

    Science.gov (United States)

    Han, Yiping W

    2015-02-01

    Fusobacterium nucleatum is an anaerobic oral commensal and a periodontal pathogen associated with a wide spectrum of human diseases. This article reviews its implication in adverse pregnancy outcomes (chorioamnionitis, preterm birth, stillbirth, neonatal sepsis, preeclampsia), GI disorders (colorectal cancer, inflammatory bowel disease, appendicitis), cardiovascular disease, rheumatoid arthritis, respiratory tract infections, Lemierre's syndrome and Alzheimer's disease. The virulence mechanisms involved in the diseases are discussed, with emphasis on its colonization, systemic dissemination, and induction of host inflammatory and tumorigenic responses. The FadA adhesin/invasin conserved in F. nucleatum is a key virulence factor and a potential diagnostic marker for F. nucleatum-associated diseases. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Bacterial toxins as pathogen weapons against phagocytes

    Directory of Open Access Journals (Sweden)

    Ana edo Vale

    2016-02-01

    Full Text Available Bacterial toxins are virulence factors that manipulate host cell functions and take over the control of vital processes of living organisms to favour microbial infection. Some toxins directly target innate immune cells, thereby annihilating a major branch of the host immune response. In this review we will focus on bacterial toxins that act from the extracellular milieu and hinder the function of macrophages and neutrophils. In particular, we will concentrate on toxins from Gram-positive and Gram-negative bacteria that manipulate cell signalling or induce cell death by either imposing direct damage to the host cells cytoplasmic membrane or enzymatically modifying key eukaryotic targets. Outcomes regarding pathogen dissemination, host damage and disease progression will be discussed.

  5. Identifying and controlling emerging foodborne pathogens: research needs.

    OpenAIRE

    Buchanan, R. L.

    1997-01-01

    Systems for managing the risks associated with foodborne pathogens are based on detailed knowledge of the microorganisms and the foods with which they are associated--known hazards. An emerging pathogen, however, is an unknown hazard; therefore, to control it, key data must be acquired to convert the pathogen from an unknown to a known hazard. The types of information required are similar despite the identity of the new agent. The key to rapid control is rapid mobilization of research capabil...

  6. Subversion of inflammasome activation and pyroptosis by pathogenic bacteria

    OpenAIRE

    Cunha, Larissa D.; Zamboni, Dario S.

    2013-01-01

    Activation of the inflammasome occurs in response to a notably high number of pathogenic microbes and is a broad innate immune response that effectively contributes to restriction of pathogen replication and generation of adaptive immunity. Activation of these platforms leads to caspase-1- and/or caspase-11-dependent secretion of proteins, including cytokines, and induction of a specific form of cell death called pyroptosis, which directly or indirectly contribute for restriction of pathogen ...

  7. Water microbiology. Bacterial pathogens and water.

    Science.gov (United States)

    Cabral, João P S

    2010-10-01

    Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water-cholera, typhoid fever and bacillary dysentery-is presented, focusing on the biology and ecology of the causal agents and on the diseases' characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment) and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers). Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters.

  8. Molecular Diagnosis of Pathogenic Sporothrix Species.

    Science.gov (United States)

    Rodrigues, Anderson Messias; de Hoog, G Sybren; de Camargo, Zoilo Pires

    2015-12-01

    Sporotrichosis is a chronic (sub)cutaneous infection caused by thermodimorphic fungi in the order, Ophiostomatales. These fungi are characterized by major differences in routes of transmission, host predilections, species virulence, and susceptibilities to antifungals. Sporothrix species emerge in the form of outbreaks. Large zoonoses and sapronoses are ongoing in Brazil and China, respectively. Current diagnostic methods based on morphology and physiology are inaccurate due to closely related phenotypes with overlapping components between pathogenic and non-pathogenic Sporothrix. There is a critical need for new diagnostic tools that are specific, sensitive, and cost-effective. We developed a panel of novel markers, based on calmodulin (CAL) gene sequences, for the large-scale diagnosis and epidemiology of clinically relevant members of the Sporothrix genus, and its relative, Ophiostoma. We identified specific PCR-based markers for S. brasiliensis, S. schenckii, S. globosa, S. mexicana, S. pallida, and O. stenoceras. We employed a murine model of disseminated sporotrichosis to optimize a PCR assay for detecting Sporothrix in clinical specimens. Primer-BLAST searches revealed candidate sequences that were conserved within a single species. Species-specific primers showed no significant homology with human, mouse, or microorganisms outside the Sporothrix genus. The detection limit was 10-100 fg of DNA in a single round of PCR for identifying S. brasiliensis, S. schenckii, S. globosa, S. mexicana, and S. pallida. A simple, direct PCR assay, with conidia as a source of DNA, was effective for rapid, low-cost genotyping. Samples from a murine model of disseminated sporotrichosis confirmed the feasibility of detecting S. brasiliensis and S. schenckii DNA in spleen, liver, lungs, heart, brain, kidney, tail, and feces of infected animals. This PCR-based method could successfully detect and identify a single species in samples from cultures and from clinical specimens. The

  9. Molecular Diagnosis of Pathogenic Sporothrix Species.

    Directory of Open Access Journals (Sweden)

    Anderson Messias Rodrigues

    2015-12-01

    Full Text Available Sporotrichosis is a chronic (subcutaneous infection caused by thermodimorphic fungi in the order, Ophiostomatales. These fungi are characterized by major differences in routes of transmission, host predilections, species virulence, and susceptibilities to antifungals. Sporothrix species emerge in the form of outbreaks. Large zoonoses and sapronoses are ongoing in Brazil and China, respectively. Current diagnostic methods based on morphology and physiology are inaccurate due to closely related phenotypes with overlapping components between pathogenic and non-pathogenic Sporothrix. There is a critical need for new diagnostic tools that are specific, sensitive, and cost-effective.We developed a panel of novel markers, based on calmodulin (CAL gene sequences, for the large-scale diagnosis and epidemiology of clinically relevant members of the Sporothrix genus, and its relative, Ophiostoma. We identified specific PCR-based markers for S. brasiliensis, S. schenckii, S. globosa, S. mexicana, S. pallida, and O. stenoceras. We employed a murine model of disseminated sporotrichosis to optimize a PCR assay for detecting Sporothrix in clinical specimens.Primer-BLAST searches revealed candidate sequences that were conserved within a single species. Species-specific primers showed no significant homology with human, mouse, or microorganisms outside the Sporothrix genus. The detection limit was 10-100 fg of DNA in a single round of PCR for identifying S. brasiliensis, S. schenckii, S. globosa, S. mexicana, and S. pallida. A simple, direct PCR assay, with conidia as a source of DNA, was effective for rapid, low-cost genotyping. Samples from a murine model of disseminated sporotrichosis confirmed the feasibility of detecting S. brasiliensis and S. schenckii DNA in spleen, liver, lungs, heart, brain, kidney, tail, and feces of infected animals.This PCR-based method could successfully detect and identify a single species in samples from cultures and from clinical

  10. Investigating Ebola virus pathogenicity using molecular dynamics.

    Science.gov (United States)

    Pappalardo, Morena; Collu, Francesca; Macpherson, James; Michaelis, Martin; Fraternali, Franca; Wass, Mark N

    2017-08-11

    Ebolaviruses have been known to cause deadly disease in humans for 40 years and have recently been demonstrated in West Africa to be able to cause large outbreaks. Four Ebolavirus species cause severe disease associated with high mortality in humans. Reston viruses are the only Ebolaviruses that do not cause disease in humans. Conserved amino acid changes in the Reston virus protein VP24 compared to VP24 of other Ebolaviruses have been suggested to alter VP24 binding to host cell karyopherins resulting in impaired inhibition of interferon signalling, which may explain the difference in human pathogenicity. Here we used protein structural analysis and molecular dynamics to further elucidate the interaction between VP24 and KPNA5. As a control experiment, we compared the interaction of wild-type and R137A-mutant (known to affect KPNA5 binding) Ebola virus VP24 with KPNA5. Results confirmed that the R137A mutation weakens direct VP24-KPNA5 binding and enables water molecules to penetrate at the interface. Similarly, Reston virus VP24 displayed a weaker interaction with KPNA5 than Ebola virus VP24, which is likely to reduce the ability of Reston virus VP24 to prevent host cell interferon signalling. Our results provide novel molecular detail on the interaction of Reston virus VP24 and Ebola virus VP24 with human KPNA5. The results indicate a weaker interaction of Reston virus VP24 with KPNA5 than Ebola virus VP24, which is probably associated with a decreased ability to interfere with the host cell interferon response. Hence, our study provides further evidence that VP24 is a key player in determining Ebolavirus pathogenicity.

  11. Persistence of Nosocomial Pathogens on Various Fabrics

    Science.gov (United States)

    Koca, Ozlem; Altoparlak, Ulku; Ayyildiz, Ahmet; Kaynar, Hasan

    2012-01-01

    Objective: Fabrics can become contaminated with high numbers of microorganisms that may be pathogenic to patients in a hospital setting and can play an important role in the chain of infection. The aim of this study was to investigate the survival of several clinical bacterial and fungal isolates on several fabrics commonly used in hospitals. Materials and Methods: Bacterial and fungal survival was tested on the following materials, each of which are commonly used in our hospital: 100% smooth cotton, 60% cotton-40% polyester, 100% wool and 100% silk. One isolate each of Candida albicans, Candida tropicalis, Candida krusei, Candida glabrata, Candida parapsilosis, Geotrichum candidum, Aspergillus fumigatus, Cryptococcus neoformans, vancomycin resistant Enterococcus faecium (VRE, methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum beta-lactamase (ESBL) positive Escherichia coli, inducible beta-lactamase (IBL) positive Pseudomonas aeruginosa, IBL-positive Acinetobacter baumannii and Stenotrophomonas maltophilia were used to contaminate fabrics. The survival of these microorganisms was studied by testing the fabric swatches for microbial growth. Results: The median survival times for all the tested bacteria and fungi were as follows: 26 days on cotton, 26.5 days on cotton-polyester, 28 days on silk, and 30 days on wool. Among the bacterial species tested, E. faecium had the longest survival time on cotton-polyester fabrics. For the fungal isolates, it was observed that C. tropicalis and C. krusei survived for the shortest amount of time on cotton fabrics in the present study. Conclusion: This survival data indicate that pathogenic microorganisms can survive from days to months on commonly used hospital fabrics. These findings indicate that current recommendations for the proper disinfection or sterilization of fabrics used in hospitals should be followed to minimize cross-contamination and prevent nosocomial infections. PMID:25610201

  12. Water Microbiology. Bacterial Pathogens and Water

    Directory of Open Access Journals (Sweden)

    João P. S. Cabral

    2010-10-01

    Full Text Available Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water—cholera, typhoid fever and bacillary dysentery—is presented, focusing on the biology and ecology of the causal agents and on the diseases’ characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers. Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters.

  13. T3SS-dependent microvascular thrombosis and ischemic enteritis in human gut xenografts infected with enteropathogenicEscherichia coli.

    Science.gov (United States)

    Nissim-Eliraz, Einat; Nir, Eilam; Shoval, Irit; Marsiano, Noga; Nissan, Israel; Shemesh, Hadar; Nagy, Nandor; Goldstein, Allan M; Gutnick, Michael; Rosenshine, Ilan; Yagel, Simcha; Shpigel, Nahum Y

    2017-08-07

    Enteropathogenic Escherichia coli (EPEC) is a leading cause of severe intestinal disease and infant mortality in developing countries. Virulence is mediated by a type three secretion system (T3SS) causing the hallmark lesions of attaching and effacing (AE) and actin-rich pedestal formation beneath the infecting bacteria on the apical surface of enterocytes. EPEC is a human-specific pathogen whose pathogenesis cannot be studied in animal models. We therefore established an EPEC infection model in human gut xenografts in SCID mice and used it to study the role of T3SS in the pathogenesis of the disease. Following EPEC O127:H6 strain E2348/69 infection, T3SS-dependent AE lesions and pedestals were demonstrated in all infected xenografts. We report here the development of T3SS-dependent intestinal thrombotic microangiopathy (iTMA) and ischemic enteritis in ∼50% of infected human gut xenografts. Using species-specific CD31 immunostaining, we showed that iTMA was limited to the larger human-mouse chimeric blood vessels which are located between the muscularis mucosa and circular muscular layer of the human gut. These blood vessels were massively invaded by bacteria which adhered to and formed pedestals on endothelial cells and aggregated with mouse neutrophils in the lumen. We conclude that endothelial infection, iTMA and ischemic enteritis might be central mechanisms underlying severe EPEC-mediated disease. Copyright © 2017 American Society for Microbiology.

  14. Engineering the Controlled Assembly of Filamentous Injectisomes in E. coli K-12 for Protein Translocation into Mammalian Cells.

    Science.gov (United States)

    Ruano-Gallego, David; Álvarez, Beatriz; Fernández, Luis Ángel

    2015-09-18

    Bacterial pathogens containing type III protein secretion systems (T3SS) assemble large needle-like protein complexes in the bacterial envelope, called injectisomes, for translocation of protein effectors into host cells. The application of these "molecular syringes" for the injection of proteins into mammalian cells is hindered by their structural and genomic complexity, requiring multiple polypeptides encoded along with effectors in various transcriptional units (TUs) with intricate regulation. In this work, we have rationally designed the controlled expression of the filamentous injectisomes found in enteropathogenic Escherichia coli (EPEC) in the nonpathogenic strain E. coli K-12. All structural components of EPEC injectisomes, encoded in a genomic island called the locus of enterocyte effacement (LEE), were engineered in five TUs (eLEEs) excluding effectors, promoters and transcriptional regulators. These eLEEs were placed under the control of the IPTG-inducible promoter Ptac and integrated into specific chromosomal sites of E. coli K-12 using a marker-less strategy. The resulting strain, named synthetic injector E. coli (SIEC), assembles filamentous injectisomes similar to those in EPEC. SIEC injectisomes form pores in the host plasma membrane and are able to translocate T3-substrate proteins (e.g., translocated intimin receptor, Tir) into the cytoplasm of HeLa cells reproducing the phenotypes of intimate attachment and polymerization of actin-pedestals elicited by EPEC bacteria. Hence, SIEC strain allows the controlled expression of functional filamentous injectisomes for efficient translocation of proteins with T3S-signals into mammalian cells.

  15. Analysis of the expression, regulation and export of NleA-E in Escherichia coli O157 : H7.

    Science.gov (United States)

    Roe, Andrew J; Tysall, Luke; Dransfield, Tracy; Wang, Dai; Fraser-Pitt, Douglas; Mahajan, Arvind; Constandinou, Chrystala; Inglis, Neil; Downing, Alison; Talbot, Richard; Smith, David G E; Gally, David L

    2007-05-01

    Previous work has shown that locus of enterocyte effacement (LEE)-encoded effector proteins such as Tir and Map can be exported via the type III secretion system (T3SS) of Escherichia coli O157 : H7. Additionally, a family of non-LEE-encoded (Nle) effector proteins has been shown to be secreted from Citrobacter rodentium, homologues of which are located on the E. coli O157 chromosome. While NleA has been shown to be secreted from pathogenic E. coli, the secretion of other Nle effector proteins has only been detected under induced conditions, or using a mutated T3SS. This study aimed to determine: (1) which nle genes are expressed in E. coli O157 : H7 under secretion-permissive conditions; (2) if Nle proteins are secreted from wild-type E. coli O157 : H7 under secretion-permissive conditions; and (3) if nle gene expression is regulated co-ordinately with other LEE-encoded effectors. Using data generated from a combination of transcriptome arrays, reporter fusions and proteomics, it was demonstrated that only nleA is expressed co-ordinately with the LEE. Secretion and expression of NleA were regulated directly or indirectly by ler, a key activator of the LEE. MS confirmed the secretion of NleA into the culture supernatant, while NleB-F were not detected.

  16. The NAG Sensor NagC Regulates LEE Gene Expression and Contributes to Gut Colonization by Escherichia coli O157:H7

    Directory of Open Access Journals (Sweden)

    Josée Harel

    2017-04-01

    Full Text Available Enterohemorrhagic Escherichia coli (EHEC O157:H7 are human pathogens responsible for bloody diarrhea and renal failures. EHEC employ a type 3 secretion system to attach directly to the human colonic epithelium. This structure is encoded by the locus of enterocyte effacement (LEE whose expression is regulated in response to specific nutrients. In this study, we show that the mucin-derived sugars N-acetylglucosamine (NAG and N-acetylneuraminic acid (NANA inhibit EHEC adhesion to epithelial cells through down-regulation of LEE expression. The effect of NAG and NANA is dependent on NagC, a transcriptional repressor of the NAG catabolism in E. coli. We show that NagC is an activator of the LEE1 operon and a critical regulator for the colonization of mice intestine by EHEC. Finally, we demonstrate that NAG and NANA as well as the metabolic activity of Bacteroides thetaiotaomicron affect the in vivo fitness of EHEC in a NagC-dependent manner. This study highlights the role of NagC in coordinating metabolism and LEE expression in EHEC and in promoting EHEC colonization in vivo.

  17. Transcriptional Activator GmrA, Encoded in Genomic Island OI-29, Controls the Motility of EnterohemorrhagicEscherichia coliO157:H7.

    Science.gov (United States)

    Yang, Bin; Wang, Shaomeng; Huang, Jianxiao; Yin, Zhiqiu; Jiang, Lingyan; Hou, Wenqi; Li, Xiaomin; Feng, Lu

    2018-01-01

    Enterohemorrhagic Escherichia coli O157:H7 is a major human enteric pathogen capable of causing large outbreaks of severe infections that induce bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. Its genome contains 177 unique O islands (OIs) including those carrying the main virulence elements, Shiga toxin-converting phages (OI-45 and OI-93) and locus for enterocyte effacement (OI-148). However, many of these islands harbor only genes of unknown function. Here, we demonstrate that OI-29 encodes a newly discovered transcriptional activator, Z0639 (named GmrA), that is required for motility and flagellar synthesis in O157:H7. GmrA directly binds to the promoter of fliA , an RNA polymerase sigma factor, and thereby regulates flagellar genes controlled by FliA. Expression of gmrA is maximal under host conditions (37°C, neutral pH, and physiological osmolarity), and in the presence of host epithelial cells, indicative of a role of this gene in infection by promoting motility. Finally, GmrA was found to be a widespread regulator of bacterial motility and flagellar synthesis in different pathotypes of E. coli . Our work largely enriches our understanding of bacterial motility control, and provides another example of regulators acquired laterally that mediate flagellar synthesis.

  18. DOCK2 confers immunity and intestinal colonization resistance to Citrobacter rodentium infection.

    Science.gov (United States)

    Liu, Zhiping; Man, Si Ming; Zhu, Qifan; Vogel, Peter; Frase, Sharon; Fukui, Yoshinori; Kanneganti, Thirumala-Devi

    2016-06-13

    Food poisoning is one of the leading causes of morbidity and mortality in the world. Citrobacter rodentium is an enteric pathogen which attaches itself to enterocytes and induces attachment and effacing (A/E) lesions. The ability of the bacterium to cause infection requires subversion of the host actin cytoskeleton. Rac-dependent actin polymerization is activated by a guanine nucleotide exchange factor known as Dedicator of cytokinesis 2 (DOCK2). However, the role of DOCK2 in infectious disease is largely unexplored. Here, we found that mice lacking DOCK2 were susceptible to C. rodentium infection. These mice harbored increased levels of C. rodentium bacteria, showed more pronounced weight loss and inflammation-associated pathology, and were prone to bacterial dissemination to the systemic organs compared with wild-type mice. We found that mice lacking DOCK2 were more susceptible to C. rodentium attachment to intestinal epithelial cells. Therefore, our results underscored an important role of DOCK2 for gastrointestinal immunity to C. rodentium infection.

  19. Multiplex detection of plant pathogens using a microsphere immunoassay technology.

    Directory of Open Access Journals (Sweden)

    Ratthaphol Charlermroj

    Full Text Available Plant pathogens are a serious problem for seed export, plant disease control and plant quarantine. Rapid and accurate screening tests are urgently required to protect and prevent plant diseases spreading worldwide. A novel multiplex detection method was developed based on microsphere immunoassays to simultaneously detect four important plant pathogens: a fruit blotch bacterium Acidovorax avenae subsp. citrulli (Aac, chilli vein-banding mottle virus (CVbMV, potyvirus, watermelon silver mottle virus (WSMoV, tospovirus serogroup IV and melon yellow spot virus (MYSV, tospovirus. An antibody for each plant pathogen was linked on a fluorescence-coded magnetic microsphere set which was used to capture corresponding pathogen. The presence of pathogens was detected by R-phycoerythrin (RPE-labeled antibodies specific to the pathogens. The assay conditions were optimized by identifying appropriate antibody pairs, blocking buffer, concentration of RPE-labeled antibodies and assay time. Once conditions were optimized, the assay was able to detect all four plant pathogens precisely and accurately with substantially higher sensitivity than enzyme-linked immunosorbent assay (ELISA when spiked in buffer and in healthy watermelon leaf extract. The assay time of the microsphere immunoassay (1 hour was much shorter than that of ELISA (4 hours. This system was also shown to be capable of detecting the pathogens in naturally infected plant samples and is a major advancement in plant pathogen detection.

  20. Multiplex detection of plant pathogens using a microsphere immunoassay technology.

    Science.gov (United States)

    Charlermroj, Ratthaphol; Himananto, Orawan; Seepiban, Channarong; Kumpoosiri, Mallika; Warin, Nuchnard; Oplatowska, Michalina; Gajanandana, Oraprapai; Grant, Irene R; Karoonuthaisiri, Nitsara; Elliott, Christopher T

    2013-01-01

    Plant pathogens are a serious problem for seed export, plant disease control and plant quarantine. Rapid and accurate screening tests are urgently required to protect and prevent plant diseases spreading worldwide. A novel multiplex detection method was developed based on microsphere immunoassays to simultaneously detect four important plant pathogens: a fruit blotch bacterium Acidovorax avenae subsp. citrulli (Aac), chilli vein-banding mottle virus (CVbMV, potyvirus), watermelon silver mottle virus (WSMoV, tospovirus serogroup IV) and melon yellow spot virus (MYSV, tospovirus). An antibody for each plant pathogen was linked on a fluorescence-coded magnetic microsphere set which was used to capture corresponding pathogen. The presence of pathogens was detected by R-phycoerythrin (RPE)-labeled antibodies specific to the pathogens. The assay conditions were optimized by identifying appropriate antibody pairs, blocking buffer, concentration of RPE-labeled antibodies and assay time. Once conditions were optimized, the assay was able to detect all four plant pathogens precisely and accurately with substantially higher sensitivity than enzyme-linked immunosorbent assay (ELISA) when spiked in buffer and in healthy watermelon leaf extract. The assay time of the microsphere immunoassay (1 hour) was much shorter than that of ELISA (4 hours). This system was also shown to be capable of detecting the pathogens in naturally infected plant samples and is a major advancement in plant pathogen detection.

  1. Integrated dataset of screening hits against multiple neglected disease pathogens.

    Directory of Open Access Journals (Sweden)

    Solomon Nwaka

    2011-12-01

    Full Text Available New chemical entities are desperately needed that overcome the limitations of existing drugs for neglected diseases. Screening a diverse library of 10,000 drug-like compounds against 7 neglected disease pathogens resulted in an integrated dataset of 744 hits. We discuss the prioritization of these hits for each pathogen and the strong correlation observed between compounds active against more than two pathogens and mammalian cell toxicity. Our work suggests that the efficiency of early drug discovery for neglected diseases can be enhanced through a collaborative, multi-pathogen approach.

  2. Pathogenic and molecular characterisation of Pythium spp. inducing ...

    African Journals Online (AJOL)

    Pathogenic and molecular characterisation of Pythium spp. inducing root rot symptoms in other crops intercropped with beans in Southwestern Uganda. Virginia Gichuru, Robin Buruchara, Patrick Okori ...

  3. Models of Caenorhabditis elegans infection by bacterial and fungal pathogens.

    Science.gov (United States)

    Powell, Jennifer R; Ausubel, Frederick M

    2008-01-01

    The nematode Caenorhabditis elegans is a simple model host for studying the relationship between the animal innate immune system and a variety of bacterial and fungal pathogens. Extensive genetic and molecular tools are available in C. elegans, facilitating an in-depth analysis of host defense factors and pathogen virulence factors. Many of these factors are conserved in insects and mammals, indicating the relevance of the nematode model to the vertebrate innate immune response. Here, we describe pathogen assays for a selection of the most commonly studied bacterial and fungal pathogens using the C. elegans model system.

  4. Pathogens distribution and drug sensitivity of chronic dacryocystitis

    Directory of Open Access Journals (Sweden)

    Yang-Yang Xie

    2014-10-01

    Full Text Available AIM: To analyze the pathogens and drug sensitivity of chronic dacryocystitis in order to provide evidence for clinical drug use.METHODS: Lacrimal secretion of 171 cases with chronic dacryocystitis was sampled for pathogenic bacteria culture identification and drug sensitivity test. Based on the results, the isolation rate of pathogens strains, the pathogens kind of chronic dacryoeystitis, main pathogens of chronic dacryocystitis, and sensitive drug for pathogens were analyzed.RESULTS: The isolation rate of pathogens strains was 76.61%(131 cases. The pathogens constituting the chronic dacryocystitis were predominantly gram-positive coccus,the percentage was 72.52%(95 cases, among which staphylococcus hominis occupied 27.48%(36 cases, staphylococcus epidermidis 16.79%(22 cases, streptococcus viridans 12.98%(17 cases. The majority of these bacteria were sensitive to cefoperazone-sulbactam, tobramycin, gentamicin and levofloxacin. For gram-positive coccus, cefoperazone-sulbactam, gentamicin and tobramycin were the most sensitive drug. For gram-negative bacilli, cefoperazone-sulbactam, tobramycin and levofloxacin were most sensitive drug.CONCLUSION: Staphylococcus hominis is the main pathogen of chronic dacryocystitis, tobramycin can be used as the first choice for local treatment of chronic dacryocystitis.

  5. Manipulation of costimulatory molecules by intracellular pathogens: veni, vidi, vici!!

    Directory of Open Access Journals (Sweden)

    Nargis Khan

    Full Text Available Some of the most successful pathogens of human, such as Mycobacterium tuberculosis (Mtb, HIV, and Leishmania donovani not only establish chronic infections but also remain a grave global threat. These pathogens have developed innovative strategies to evade immune responses such as antigenic shift and drift, interference with antigen processing/presentation, subversion of phagocytosis, induction of immune regulatory pathways, and manipulation of the costimulatory molecules. Costimulatory molecules expressed on the surface of various cells play a decisive role in the initiation and sustenance of immunity. Exploitation of the "code of conduct" of costimulation pathways provides evolutionary incentive to the pathogens and thereby abates the functioning of the immune system. Here we review how Mtb, HIV, Leishmania sp., and other pathogens manipulate costimulatory molecules to establish chronic infection. Impairment by pathogens in the signaling events delivered by costimulatory molecules may be responsible for defective T-cell responses; consequently organisms grow unhindered in the host cells. This review summarizes the convergent devices that pathogens employ to tune and tame the immune system using costimulatory molecules. Studying host-pathogen interaction in context with costimulatory signals may unveil the molecular mechanism that will help in understanding the survival/death of the pathogens. We emphasize that the very same pathways can potentially be exploited to develop immunotherapeutic strategies to eliminate intracellular pathogens.

  6. Development of an aquatic pathogen database (AquaPathogen X) and its utilization in tracking emerging fish virus pathogens in North America

    Science.gov (United States)

    Emmenegger, E.J.; Kentop, E.; Thompson, T.M.; Pittam, S.; Ryan, A.; Keon, D.; Carlino, J.A.; Ranson, J.; Life, R.B.; Troyer, R.M.; Garver, K.A.; Kurath, G.

    2011-01-01

    The AquaPathogen X database is a template for recording information on individual isolates of aquatic pathogens and is freely available for download (http://wfrc.usgs.gov). This database can accommodate the nucleotide sequence data generated in molecular epidemiological studies along with the myriad of abiotic and biotic traits associated with isolates of various pathogens (e.g. viruses, parasites and bacteria) from multiple aquatic animal host species (e.g. fish, shellfish and shrimp). The cataloguing of isolates from different aquatic pathogens simultaneously is a unique feature to the AquaPathogen X database, which can be used in surveillance of emerging aquatic animal diseases and elucidation of key risk factors associated with pathogen incursions into new water systems. An application of the template database that stores the epidemiological profiles of fish virus isolates, called Fish ViroTrak, was also developed. Exported records for two aquatic rhabdovirus species emerging in North America were used in the implementation of two separate web-accessible databases: the Molecular Epidemiology of Aquatic Pathogens infectious haematopoietic necrosis virus (MEAP-IHNV) database (http://gis.nacse.org/ihnv/) released in 2006 and the MEAP- viral haemorrhagic septicaemia virus (http://gis.nacse.org/vhsv/) database released in 2010.

  7. LEGER: knowledge database and visualization tool for comparative genomics of pathogenic and non-pathogenic Listeria species

    OpenAIRE

    Dieterich, Guido; Kärst, Uwe; Fischer, Elmar; Wehland, Jürgen; Jänsch, Lothar

    2005-01-01

    Listeria species are ubiquitous in the environment and often contaminate foods because they grow under conditions used for food preservation. Listeria monocytogenes, the human and animal pathogen, causes Listeriosis, an infection with a high mortality rate in risk groups such as immune-compromised individuals. Furthermore, L.monocytogenes is a model organism for the study of intracellular bacterial pathogens. The publication of its genome sequence and that of the non-pathogenic species Lister...

  8. Use of Molecular Pathogenicity Indices to Identify Pathogenic Strains of Pasteurella multocida.

    Science.gov (United States)

    Furian, Thales Quedi; Borges, Karen Apellanis; Pilatti, Roberta Marmitt; de Almeida, Camila Neves; Streck, André Felipe; de Emery, Brunna Dias; Nascimento, Vladimir Pinheiro do; Salle, Carlos Tadeu Pippi; de Souza Moraes, Hamilton Luiz

    2016-12-01

    In addition to being the causative agent of fowl cholera (FC), Pasteurella multocida is also one of the most prevalent opportunistic pathogens associated with respiratory diseases in various hosts. However, understanding of the traits that distinguish the virulent isolates that cause FC is still limited. The objective of this study was to characterize P. multocida isolates of Brazil by PCR-restriction fragment length polymorphism (PCR-RFLP) analysis in order to determine if strain-type correlates with virulence or with 22 previously studied virulence genes. The PCR-RFLP was used to classify the isolates into seven strain types, and the isolates in Profile II had a higher pathogenicity index (P multocida .

  9. Isoenzyme patterns of pathogenic and non-pathogenic Naegleria spp. using agarose isoelectric focusing.

    Science.gov (United States)

    De Jonckheere, J F

    1982-01-01

    Using agarose isoelectric focusing, the isoenzyme patterns of 7 different enzymes were compared in 52 Naegleria strains. The pathogenic N. fowleri was found the most homogeneous species. N. lovaniensis seems to be constituted of different types which form nevertheless a cohesive group. Within N. gruberi, large interstrain band variations were found in almost all enzyme systems. A re-examination of the taxonomic position of this species may therefore be taken into consideration. High temperature strains from Australia were confirmed to be different from N. lovaniensis. Members of a new pathogenic Naegleria sp., N. australiensis, seem to occur in Europe. Large thermophilic strains with many large pores in the cysts show identical zymograms and may constitute a new species or genus.

  10. Comparative genomics and the evolution of pathogenicity in human pathogenic fungi.

    LENUS (Irish Health Repository)

    Moran, Gary P

    2011-01-01

    Because most fungi have evolved to be free-living in the environment and because the infections they cause are usually opportunistic in nature, it is often difficult to identify specific traits that contribute to fungal pathogenesis. In recent years, there has been a surge in the number of sequenced genomes of human fungal pathogens, and comparison of these sequences has proved to be an excellent resource for exploring commonalities and differences in how these species interact with their hosts. In order to survive in the human body, fungi must be able to adapt to new nutrient sources and environmental stresses. Therefore, genes involved in carbohydrate and amino acid metabolism and transport and genes encoding secondary metabolites tend to be overrepresented in pathogenic species (e.g., Aspergillus fumigatus). However, it is clear that human commensal yeast species such as Candida albicans have also evolved a range of specific factors that facilitate direct interaction with host tissues. The evolution of virulence across the human pathogenic fungi has occurred largely through very similar mechanisms. One of the most important mechanisms is gene duplication and the expansion of gene families, particularly in subtelomeric regions. Unlike the case for prokaryotic pathogens, horizontal transfer of genes between species and other genera does not seem to have played a significant role in the evolution of fungal virulence. New sequencing technologies promise the prospect of even greater numbers of genome sequences, facilitating the sequencing of multiple genomes and transcriptomes within individual species, and will undoubtedly contribute to a deeper insight into fungal pathogenesis.

  11. The Quantitative Basis of the Arabidopsis Innate Immune System to Endemic Pathogens Depends on Pathogen Genetics.

    Science.gov (United States)

    Corwin, Jason A; Copeland, Daniel; Feusier, Julie; Subedy, Anushriya; Eshbaugh, Robert; Palmer, Christine; Maloof, Julin; Kliebenstein, Daniel J

    2016-02-01

    The most established model of the eukaryotic innate immune system is derived from examples of large effect monogenic quantitative resistance to pathogens. However, many host-pathogen interactions involve many genes of small to medium effect and exhibit quantitative resistance. We used the Arabidopsis-Botrytis pathosystem to explore the quantitative genetic architecture underlying host innate immune system in a population of Arabidopsis thaliana. By infecting a diverse panel of Arabidopsis accessions with four phenotypically and genotypically distinct isolates of the fungal necrotroph B. cinerea, we identified a total of 2,982 genes associated with quantitative resistance using lesion area and 3,354 genes associated with camalexin production as measures of the interaction. Most genes were associated with resistance to a specific Botrytis isolate, which demonstrates the influence of pathogen genetic variation in analyzing host quantitative resistance. While known resistance genes, such as receptor-like kinases (RLKs) and nucleotide-binding site leucine-rich repeat proteins (NLRs), were found to be enriched among associated genes, they only account for a small fraction of the total genes associated with quantitative resistance. Using publically available co-expression data, we condensed the quantitative resistance associated genes into co-expressed gene networks. GO analysis of these networks implicated several biological processes commonly connected to disease resistance, including defense hormone signaling and ROS production, as well as novel processes, such as leaf development. Validation of single gene T-DNA knockouts in a Col-0 background demonstrate a high success rate (60%) when accounting for differences in environmental and Botrytis genetic variation. This study shows that the genetic architecture underlying host innate immune system is extremely complex and is likely able to sense and respond to differential virulence among pathogen genotypes.

  12. The Quantitative Basis of the Arabidopsis Innate Immune System to Endemic Pathogens Depends on Pathogen Genetics.

    Directory of Open Access Journals (Sweden)

    Jason A Corwin

    2016-02-01

    Full Text Available The most established model of the eukaryotic innate immune system is derived from examples of large effect monogenic quantitative resistance to pathogens. However, many host-pathogen interactions involve many genes of small to medium effect and exhibit quantitative resistance. We used the Arabidopsis-Botrytis pathosystem to explore the quantitative genetic architecture underlying host innate immune system in a population of Arabidopsis thaliana. By infecting a diverse panel of Arabidopsis accessions with four phenotypically and genotypically distinct isolates of the fungal necrotroph B. cinerea, we identified a total of 2,982 genes associated with quantitative resistance using lesion area and 3,354 genes associated with camalexin production as measures of the interaction. Most genes were associated with resistance to a specific Botrytis isolate, which demonstrates the influence of pathogen genetic variation in analyzing host quantitative resistance. While known resistance genes, such as receptor-like kinases (RLKs and nucleotide-binding site leucine-rich repeat proteins (NLRs, were found to be enriched among associated genes, they only account for a small fraction of the total genes associated with quantitative resistance. Using publically available co-expression data, we condensed the quantitative resistance associated genes into co-expressed gene networks. GO analysis of these networks implicated several biological processes commonly connected to disease resistance, including defense hormone signaling and ROS production, as well as novel processes, such as leaf development. Validation of single gene T-DNA knockouts in a Col-0 background demonstrate a high success rate (60% when accounting for differences in environmental and Botrytis genetic variation. This study shows that the genetic architecture underlying host innate immune system is extremely complex and is likely able to sense and respond to differential virulence among pathogen

  13. Periodontal pathogen CaZymes: host-pathogen biology, biochemistry and biotechnological exploitation

    OpenAIRE

    Stafford, Graham P.; Frey, Andrew M.; Satur, Marianne J.

    2017-01-01

    ABSTRACT One often neglected aspect of the host-pathogen interface is the presence of myriad glycoproteins and the carbohydrate glycans that they present. These are often the first point of contact for bacteria, with the oral cavity being rich in glycoprotein mucins within secretions such as saliva and crevicular fluid. Therefore, unsurprisingly, bacteria have evolved a myriad of enzymes (that one can consider virulence attributes) to access these glycans to allow attachment to host surfaces,...

  14. Distribution of indigenous bacterial pathogens and potential pathogens associated with roof-harvested rainwater.

    Science.gov (United States)

    Dobrowsky, P H; De Kwaadsteniet, M; Cloete, T E; Khan, W

    2014-04-01

    The harvesting of rainwater is gaining acceptance among many governmental authorities in countries such as Australia, Germany, and South Africa, among others. However, conflicting reports on the microbial quality of harvested rainwater have been published. To monitor the presence of potential pathogenic bacteria during high-rainfall periods, rainwater from 29 rainwater tanks was sampled on four occasions (during June and August 2012) in a sustainable housing project in Kleinmond, South Africa. This resulted in the collection of 116 harvested rainwater samples in total throughout the sampling period. The identities of the dominant, indigenous, presumptive pathogenic isolates obtained from the rainwater samples throughout the sampling period were confirmed through universal 16S rRNA PCR, and the results revealed that Pseudomonas (19% of samples) was the dominant genus isolated, followed by Aeromonas (16%), Klebsiella (11%), and Enterobacter (9%). PCR assays employing genus-specific primers also confirmed the presence of Aeromonas spp. (16%), Klebsiella spp. (47%), Legionella spp. (73%), Pseudomonas spp. (13%), Salmonella spp. (6%), Shigella spp. (27%), and Yersinia spp. (28%) in the harvested rainwater samples. In addition, on one sampling occasion, Giardia spp. were detected in 25% of the eight tank water samples analyzed. This study highlights the diverse array of pathogenic bacteria that persist in harvested rainwater during high-rainfall periods. The consumption of untreated harvested rainwater could thus pose a potential significant health threat to consumers, especially children and immunocompromised individuals, and it is recommended that harvested rainwater be treated for safe usage as an alternative water source.

  15. Infectious bursal disease: evaluation of pathogenicity of commercial vaccines from Brazil in specific pathogen free chichens

    Directory of Open Access Journals (Sweden)

    HLS Moraes

    2004-12-01

    Full Text Available Infectious Bursal Disease (IBD is a chicken disease economically important for the poultry industry in function of the immune depression that it causes. Disease control is made with different vaccines and vaccination programs. In present work, the pathogenicity of 3 intermediate vaccines (I1, I2 and I3, 2 intermediate more pathogenic (IP1 and IP2 and 3 vaccines containing strong virus (F1, F2 and F3 was evaluated. Birds vaccinated with IP1, IP2, F1, F2 and F3 showed significantly lower bursa size in relation to control animals and animals vaccinated with I1, I2 and I3. On the other hand, vaccines I1 and I3 induced antibody titers higher than the control and lower than I2, IP1, IP2, F1, F2 and F3. Histological scores showed that vaccines I1, I2 and I3 induced similar injury degree, although I2 and I3 were not different from the control, whereas I1 was slightly different. Strong vaccines induced more pronounced lesions than the other tested vaccines. These findings suggest that strong vaccines are able to cause severe bursal injuries. However, bursometry and relative weight of the bursa of Fabricius were considered inadequate to evaluate vaccine pathogenicity. Moreover, strong vaccines induced higher antibody titers than the other vaccines, although some intermediate vaccines induced similar titers.

  16. Pathogenicity of FtsK mutant of avian pathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Xu Xiaojing

    2016-03-01

    Full Text Available Introduction: Avian pathogenic Escherichia coli (APEC is a leading cause of extraintestinal infection and heavy economic losses. Imparting immunity after vaccination with live attenuated strain vaccination is an ideal strategy for infection control. This study considers an FtsK knockout mutant strain as a candidate. Material and Methods: An FtsK knockout mutant of APEC strain E058 was constructed and the pathogenicity of the mutant and wild-type strains was further evaluated in chickens. Results: The 50% lethal doses of each strain for one-day-old specific-pathogen-free (SPF chickens challenged experimentally via trachea were 105.5 and 107.0 colony-forming units (CFU respectively. Chickens challenged with the wild-type strain exhibited typical signs and lesions of avian colibacillosis, while those inoculated with the mutant strain showed mild pericarditis and pulmonary congestion. The growth rate of the FtsK mutant strain was much slower than the wild-type strain in the heart, spleen, liver, and lung of infected chickens. Conclusion: These results indicated that the APEC FtsK mutant can be attenuated for chickens, and that this mutant has the potential for the development of an APEC vaccine.

  17. Single-molecule analysis of the major glycopolymers of pathogenic and non-pathogenic yeast cells

    Science.gov (United States)

    El-Kirat-Chatel, Sofiane; Beaussart, Audrey; Alsteens, David; Sarazin, Aurore; Jouault, Thierry; Dufrêne, Yves F.

    2013-05-01

    Most microbes are coated with carbohydrates that show remarkable structural variability and play a crucial role in mediating microbial-host interactions. Understanding the functions of cell wall glycoconjugates requires detailed knowledge of their molecular organization, diversity and heterogeneity. Here we use atomic force microscopy (AFM) with tips bearing specific probes (lectins, antibodies) to analyze the major glycopolymers of pathogenic and non-pathogenic yeast cells at molecular resolution. We show that non-ubiquitous β-1,2-mannans are largely exposed on the surface of native cells from pathogenic Candida albicans and C. glabrata, the former species displaying the highest glycopolymer density and extensions. We also find that chitin, a major component of the inner layer of the yeast cell wall, is much more abundant in C. albicans. These differences in molecular properties, further supported by flow cytometry measurements, may play an important role in strengthening cell wall mechanics and immune interactions. This study demonstrates that single-molecule AFM, combined with immunological and fluorescence methods, is a powerful platform in fungal glycobiology for probing the density, distribution and extension of specific cell wall glycoconjugates. In nanomedicine, we anticipate that this new form of AFM-based nanoglycobiology will contribute to the development of sugar-based drugs, immunotherapeutics, vaccines and diagnostics.

  18. Modeling the intracellular pathogen-immune interaction with cure rate

    Science.gov (United States)

    Dubey, Balram; Dubey, Preeti; Dubey, Uma S.

    2016-09-01

    Many common and emergent infectious diseases like Influenza, SARS, Hepatitis, Ebola etc. are caused by viral pathogens. These infections can be controlled or prevented by understanding the dynamics of pathogen-immune interaction in vivo. In this paper, interaction of pathogens with uninfected and infected cells in presence or absence of immune response are considered in four different cases. In the first case, the model considers the saturated nonlinear infection rate and linear cure rate without absorption of pathogens into uninfected cells and without immune response. The next model considers the effect of absorption of pathogens into uninfected cells while all other terms are same as in the first case. The third model incorporates innate immune response, humoral immune response and Cytotoxic T lymphocytes (CTL) mediated immune response with cure rate and without absorption of pathogens into uninfected cells. The last model is an extension of the third model in which the effect of absorption of pathogens into uninfected cells has been considered. Positivity and boundedness of solutions are established to ensure the well-posedness of the problem. It has been found that all the four models have two equilibria, namely, pathogen-free equilibrium point and pathogen-present equilibrium point. In each case, stability analysis of each equilibrium point is investigated. Pathogen-free equilibrium is globally asymptotically stable when basic reproduction number is less or equal to unity. This implies that control or prevention of infection is independent of initial concentration of uninfected cells, infected cells, pathogens and immune responses in the body. The proposed models show that introduction of immune response and cure rate strongly affects the stability behavior of the system. Further, on computing basic reproduction number, it has been found to be minimum for the fourth model vis-a-vis other models. The analytical findings of each model have been exemplified by

  19. Pathogenic amoebae in power-plant cooling lakes. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Tyndall, R.L.; Willaert, E.; Stevens, A.R.

    1981-06-01

    Cooling waters and associated algae and sediments from four northern and four southern/western electric power plants were tested for the presence of pathogenic amoebae. Unheated control waters and algae/sediments from four northern and five southern/western sites were also tested. When comparing results from the test versus control sites, a significantly higher proportion (P less than or equal to 0.05) of the samples from the test sites were positive for thermophilic amoeba, thermophilic Naegleria and pathogenic Naegleria. The difference in number of samples positive for thermophilic Naegleria between heated and unheated waters, however, was attributable predominantly to the northern waters and algae/sediments. While two of four northern test sites yielded pathogenic Naegleria, seven of the eight isolates were obtained from one site. Seasonality effects relative to the isolation of the pathogen were also noted at this site. One pathogen was isolated from a southwestern test site. Pathogens were not isolated from any control sites. Some of the pathogenic isolates were analyzed serologically and classified as pathogenic Naegleria fowleri. Salinity, pH, conductivity, and bacteriological profiles did not obviously correlate with the presence or absence of pathogenic Naegleria. While thermal addition was significantly associated with the presence of thermophilic Naegleria (P less than or equal to 0.05), the data implicate other as yet undefined parameters associated with the presence of the pathogenic thermophile. Until further delineation of these parameters is effected, generalizations cannot be made concerning the effect of thermal impact on the growth of pathogenic amoeba in a particular cooling system.

  20. Phosphotyrosine-Mediated Regulation of EnterohemorrhagicEscherichia coliVirulence.

    Science.gov (United States)

    Robertson, Colin D; Hazen, Tracy H; Kaper, James B; Rasko, David A; Hansen, Anne-Marie

    2018-02-27

    Enteric pathogens with low infectious doses rely on the ability to orchestrate the expression of virulence and metabolism-associated genes in response to environmental cues for successful infection. Accordingly, the human pathogen enterohemorrhagic Escherichia coli (EHEC) employs a complex multifaceted regulatory network to link the expression of type III secretion system (T3SS) components to nutrient availability. While phosphorylation of histidine and aspartate residues on two-component system response regulators is recognized as an integral part of bacterial signaling, the involvement of phosphotyrosine-mediated control is minimally explored in Gram-negative pathogens. Our recent phosphotyrosine profiling study of E. coli identified 342 phosphorylated proteins, indicating that phosphotyrosine modifications in bacteria are more prevalent than previously anticipated. The present study demonstrates that tyrosine phosphorylation of a metabolite-responsive LacI/GalR family regulator, Cra, negatively affects T3SS expression under glycolytic conditions that are typical for the colonic lumen environment where production of the T3SS is unnecessary. Our data suggest that Cra phosphorylation affects T3SS expression by modulating the expression of ler , which encodes the major activator of EHEC virulence gene expression. Phosphorylation of the Cra Y47 residue diminishes DNA binding to fine-tune the expression of virulence-associated genes, including those of the locus of enterocyte effacement pathogenicity island that encode the T3SS, and thereby negatively affects the formation of attaching and effacing lesions. Our data indicate that tyrosine phosphorylation provides an additional mechanism to control the DNA binding of Cra and other LacI/GalR family regulators, including LacI and PurR. This study describes an initial effort to unravel the role of global phosphotyrosine signaling in the control of EHEC virulence potential. IMPORTANCE Enterohemorrhagic Escherichia coli