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Sample records for pathogenicity islands spi-1

  1. Salmonella pathogenicity island 1(SPI-1) at work.

    PubMed

    Que, Fengxia; Wu, Shuyan; Huang, Rui

    2013-06-01

    As an indispensable virulence determinant, Salmonella pathogenicity island 1(SPI-1) has gained much attention in host-pathogen interactions. More and more studies on SPI-1 have demonstrated that it is far more complex than the one we used to expect. It not only affects sophisticated activities during infection, including invasion, replication, and host responses, but also extends to other fields like biofilm formation. In addition, mutants in SPI-1 effectors have been explored as vaccines, the effective ways to prevent salmonellosis. The activity of SPI-1 is influenced by many factors which have been widely reported. Investigations on these factors may provide new insights into prevention and treatment of salmonellosis. Therefore, SPI-1 is a tempting issue worthy of further exploration. In this review, we will probe into SPI-1 systematically.

  2. Crosstalk between virulence loci: regulation of Salmonella enterica pathogenicity island 1 (SPI-1) by products of the std fimbrial operon.

    PubMed

    López-Garrido, Javier; Casadesús, Josep

    2012-01-01

    Invasion of intestinal epithelial cells is a critical step in Salmonella infection and requires the expression of genes located in Salmonella pathogenicity island 1 (SPI-1). A key factor for SPI-1 expression is DNA adenine (Dam) methylation, which activates synthesis of the SPI-1 transcriptional activator HilD. Dam-dependent regulation of hilD is postranscriptional (and therefore indirect), indicating the involvement of unknown cell functions under Dam methylation control. A genetic screen has identified the std fimbrial operon as the missing link between Dam methylation and SPI-1. We show that all genes in the std operon are part of a single transcriptional unit, and describe three previously uncharacterized ORFs (renamed stdD, stdE, and stdF). We present evidence that two such loci (stdE and stdF) are involved in Dam-dependent control of Salmonella SPI-1: in a Dam(-) background, deletion of stdE or stdF suppresses SPI-1 repression; in a Dam(+) background, constitutive expression of StdE and/or StdF represses SPI-1. Repression of SPI-1 by products of std operon explains the invasion defect of Salmonella Dam(-) mutants, which constitutively express the std operon. Dam-dependent repression of std in the ileum may be required to permit invasion, as indicated by two observations: constitutive expression of StdE and StdF reduces invasion of epithelial cells in vitro (1,000 fold) and attenuates Salmonella virulence in the mouse model (>60 fold). In turn, crosstalk between std and SPI-1 may play a role in intestinal infections by preventing expression of SPI-1 in the caecum, an intestinal compartment in which the std operon is known to be expressed.

  3. Regulation of Salmonella enterica pathogenicity island 1 (SPI-1) by the LysR-type regulator LeuO.

    PubMed

    Espinosa, Elena; Casadesús, Josep

    2014-03-01

    LeuO is a quiescent LysR-type regulator belonging to the H-NS regulon. Activation of leuO transcription represses expression of pathogenicity island 1 (SPI-1) in Salmonella enterica serovar Typhimurium and inhibits invasion of epithelial cells. Loss of HilE suppresses LeuO-mediated downregulation of SPI-1. Activation of leuO transcription reduces the level of HilD protein, and loss of HilE restores the wild type HilD level. Hence, LeuO-mediated downregulation of SPI-1 may involve inhibition of HilD activity by HilE, a view consistent with the fact that HilE is a HilD inhibitor. In vivo analyses using β-galactosidase fusions indicate that LeuO activates hilE transcription. In vitro analyses by slot blotting, electrophoretic mobility shift analysis and DNase I footprinting show that LeuO binds the hilE promoter region. Although residual SPI-1 repression by LeuO is observed in the absence of HilE, the LeuO-HilE-HilD 'pathway' appears to be the major mechanism. Because both leuO and SPI-1 are repressed by H-NS, activation of leuO transcription may provide a backup mechanism for SPI-1 repression under conditions that impair H-NS-mediated silencing.

  4. A fundamental regulatory mechanism operating through OmpR and DNA topology controls expression of Salmonella pathogenicity islands SPI-1 and SPI-2.

    PubMed

    Cameron, Andrew D S; Dorman, Charles J

    2012-01-01

    DNA topology has fundamental control over the ability of transcription factors to access their target DNA sites at gene promoters. However, the influence of DNA topology on protein-DNA and protein-protein interactions is poorly understood. For example, relaxation of DNA supercoiling strongly induces the well-studied pathogenicity gene ssrA (also called spiR) in Salmonella enterica, but neither the mechanism nor the proteins involved are known. We have found that relaxation of DNA supercoiling induces expression of the Salmonella pathogenicity island (SPI)-2 regulator ssrA as well as the SPI-1 regulator hilC through a mechanism that requires the two-component regulator OmpR-EnvZ. Additionally, the ompR promoter is autoregulated in the same fashion. Conversely, the SPI-1 regulator hilD is induced by DNA relaxation but is repressed by OmpR. Relaxation of DNA supercoiling caused an increase in OmpR binding to DNA and a concomitant decrease in binding by the nucleoid-associated protein FIS. The reciprocal occupancy of DNA by OmpR and FIS was not due to antagonism between these transcription factors, but was instead a more intrinsic response to altered DNA topology. Surprisingly, DNA relaxation had no detectable effect on the binding of the global repressor H-NS. These results reveal the underlying molecular mechanism that primes SPI genes for rapid induction at the onset of host invasion. Additionally, our results reveal novel features of the archetypal two-component regulator OmpR. OmpR binding to relaxed DNA appears to generate a locally supercoiled state, which may assist promoter activation by relocating supercoiling stress-induced destabilization of DNA strands. Much has been made of the mechanisms that have evolved to regulate horizontally-acquired genes such as SPIs, but parallels among the ssrA, hilC, and ompR promoters illustrate that a fundamental form of regulation based on DNA topology coordinates the expression of these genes regardless of their origins.

  5. A small non-coding RNA of the invasion gene island (SPI-1) represses outer membrane protein synthesis from the Salmonella core genome.

    PubMed

    Pfeiffer, Verena; Sittka, Alexandra; Tomer, Raju; Tedin, Karsten; Brinkmann, Volker; Vogel, Jörg

    2007-12-01

    The Salmonella pathogenicity island (SPI-1) encodes approximately 35 proteins involved in assembly of a type III secretion system (T3SS) which endows Salmonella with the ability to invade eukaryotic cells. We have discovered a novel SPI-1 gene, invR, which expresses an abundant small non-coding RNA (sRNA). The invR gene, which we identified in a global search for new Salmonella sRNA genes, is activated by the major SPI-1 transcription factor, HilD, under conditions that favour host cell invasion. The RNA chaperone, Hfq, is essential for the in vivo stability of the approximately 80 nt InvR RNA. Hfq binds InvR with high affinity in vitro, and InvR co-immunoprecipitates with FLAG epitope-tagged Hfq in Salmonella extracts. Surprisingly, deletion/overexpression of invR revealed no phenotype in SPI-1 regulation. In contrast, we find that InvR represses the synthesis of the abundant OmpD porin encoded by the Salmonella core genome. As invR is conserved in the early branching Salmonella bongori, we speculate that porin repression by InvR may have aided successful establishment of the SPI-1 T3SS after horizontal acquisition in the Salmonella lineage. This study identifies the first regulatory RNA of an enterobacterial pathogenicity island, and new roles for Hfq and HilD in SPI-1 gene expression.

  6. LeuO, a dormant sentinel for SPI-1?

    PubMed

    Bustamante, Víctor H; Calva, Edmundo

    2014-03-01

    A new mechanism for the turning-off of gene expression in Salmonella Pathogenicity Island 1 (SPI-1) is proposed by Espinosa and Casadesús, which involves the action of the LeuO quiescent regulator, by two different pathways. A major one through the activation of the hilE gene, where the HilE protein would in turn inactivate HilD, a major positive transcriptional regulator of SPI-1; and a minor HilE-HilD-independent pathway. This could constitute a back-up or an aid for the turn-off of SPI-1 genes mediated by the nucleoid protein H-NS.

  7. [Salmonella pathogenicity islands].

    PubMed

    Sırıken, Belgin

    2013-01-01

    Salmonella species are facultative intracellular pathogenic bacteria. They can invade macrophages, dendritic and epithelial cells. The responsible virulence genes for invasion, survival, and extraintestinal spread are located in Salmonella pathogenicity islands (SPIs). SPIs are thought to be acquired by horizontal gene transfer. Some of the SPIs are conserved throughout the Salmonella genus, and some of them are specific for certain serovars. There are differences between Salmonella serotypes in terms of adaptation to host cell, virulence factors and the resulting infection according to SPA presence and characteristics. The most important Salmonella virulence gene clusters are located in 12 pathogenicity islands. Virulence genes that are involved in the intestinal phase of infection are located in SPI-1 and SPI-2 and the remaining SPIs are required for intracellular survival, fimbrial expression, magnesium and iron uptake, multiple antibiotic resistance and the development of systemic infections. In addition SPIs, Sigma ss (RpoS) factors and adaptive acid tolerance response (ATR) are the other two important virulence factors. RpoS and ATR found in virulent Salmonella strains help the bacteria to survive under inappropriate conditions such as gastric acidity, bile salts, inadequate oxygen concentration, lack of nutrients, antimicrobial peptides, mucus and natural microbiota and also to live in phagosomes or phagolysosomes. This review article summarizes the data related to pathogenicity islands in Salmonella serotypes and some factors which play role in the regulation of virulence genes.

  8. Vaccination of chickens with SPI1-lon and SPI1-lon-fliC mutant of Salmonella enterica Serovar Enteritidis.

    PubMed

    Matulova, Marta; Havlickova, Hana; Sisak, Frantisek; Rychlik, Ivan

    2013-01-01

    The prevalence of Salmonella enterica serovar Enteritidis is gradually decreasing in poultry flocks in the EU, which may result in the demand for a vaccine that allows for the differentiation of vaccinated flocks from those infected by wild-type S. Enteritidis. In this study, we therefore constructed a (Salmonella Pathogenicity Island 1) SPI1-lon mutant with or without fliC encoding for S. Enteritidis flagellin. The combination of SPI1-lon mutations resulted in attenuated but immunogenic mutant suitable for oral vaccination of poultry. In addition, the vaccination of chickens with the SPI1-lon-fliC mutant enabled the serological differentiation of vaccinated and infected chickens. The absence of fliC therefore did not affect the immunogenicity of the vaccine strain and allowed for serological differentiation of the vaccinated chickens. The SPI1-lon-fliC mutant is therefore a suitable marker vaccine strain for oral vaccination of poultry.

  9. Role of SPI-1 in the interactions of Salmonella Typhimurium with porcine macrophages.

    PubMed

    Boyen, F; Pasmans, F; Donné, E; Van Immerseel, F; Adriaensen, C; Hernalsteens, J-P; Ducatelle, R; Haesebrouck, F

    2006-03-10

    Salmonella Pathogenicity Island 1 (SPI-1) genes are indispensable for virulence of Salmonella Typhimurium in mice after oral challenge. These genes mediate invasion in intestinal epithelial cells and induce cell death in murine macrophages. The role of SPI-1 in the pathogenesis of Salmonella Typhimurium infections in food producing animals is not known. It was the aim of the present study to characterize the interactions of a porcine Salmonella Typhimurium field strain and its isogenic mutants in the SPI-1 genes hilA, sipA and sipB with porcine macrophages. SPI-1 was found to be important in the invasion of porcine pulmonary alveolar macrophages (PAM) and the induction of the formation of spacious phagosomes. Both early and delayed cytotoxicity were seen in PAM, but only the early cytotoxicity was SPI-1 dependent. Exposure of PAM to Salmonella Typhimurium induced the production of reactive oxygen species (ROS) and interleukin-8, but no differences were noticed between the induction mediated by the wild type strain and its SPI-1 mutant strains. In conclusion, invasion of porcine macrophages and the induction of early, but not delayed, cytotoxicity by Salmonella Typhimurium is SPI-1 dependent. SPI-1 dependent invasion, however, is not a prerequisite to induce a pro-inflammatory response.

  10. The SPI-1-like Type III secretion system: more roles than you think.

    PubMed

    Egan, Frank; Barret, Matthieu; O'Gara, Fergal

    2014-01-01

    The type III secretion system (T3SS) is a protein delivery system which is involved in a wide spectrum of interactions, from mutualism to pathogenesis, between Gram negative bacteria and various eukaryotes, including plants, fungi, protozoa and mammals. Various phylogenetic families of the T3SS have been described, including the Salmonella Pathogenicity Island 1 family (SPI-1). The SPI-1 T3SS was initially associated with the virulence of enteric pathogens, but is actually found in a diverse array of bacterial species, where it can play roles in processes as different as symbiotic interactions with insects and colonization of plants. We review the multiple roles of the SPI-1 T3SS and discuss both how these discoveries are changing our perception of the SPI-1 family and what impacts this has on our understanding of the specialization of the T3SS in general.

  11. Salmonella enterica serovar Senftenberg human clinical isolates lacking SPI-1.

    PubMed

    Hu, Qinghua; Coburn, Bryan; Deng, Wanyin; Li, Yuling; Shi, Xiaolu; Lan, Quanxue; Wang, Bing; Coombes, Brian K; Finlay, B Brett

    2008-04-01

    Nontyphoidal Salmonella species cause gastrointestinal disease worldwide. The prevailing theory of Salmonella enteropathogenesis is that bacterial invasion of the intestinal epithelium is essential for virulence and that this requires the virulence-associated genomic region Salmonella pathogenicity island 1 (SPI-1). Recent studies of Salmonella enterica infection models have demonstrated that enterocolitis and diarrhea in mice and cows can occur independently of SPI-1. In this study, we sought to confirm whether two S. enterica serovar Senftenberg clinical isolates lacked genes essential for SPI-1 function. Two clinical strains were isolated and identified as being S. enterica serovar Senftenberg from four stool samples from a food-borne disease outbreak affecting seven individuals in Shenzhen, Guangdong Province, China, using conventional methods, pulsed-field gel electrophoresis and multilocus sequence typing. The possibility of coinfection with other potential bacteria or usual viruses was excluded. Two isolates were analyzed for the presence of invA, sipA, ssaR, sifA, and sopE2 by PCR and Southern blotting and were then assayed for the presence of SPI-1 by PCR and long-range PCR for fhlA-hilA, hilA-spaP, and spaP-invH and Southern blot analysis. A long-range PCR fragment from fhlA to mutS covering the 5' and 3' flanks of SPI-1 was also amplified from the two clinical isolates and sequenced. In addition, the two clinical isolates were assayed for enteroinvasiveness in vitro. Murine infection models were also examined. Biochemical tests and serotyping confirmed that the two clinical isolates are S. enterica serovar Senftenberg. However, they lacked genes critical for SPI-1 function but contained SPI-2 genes and were attenuated for the invasion of cultured intestinal epithelial cells. In conclusion, clinical S. enterica serovar Senftenberg strains isolated from a food-borne disease outbreak lack the invasion-associated locus SPI-1, indicating that SPI-1 is not

  12. SPI-1-encoded type III secretion system of Salmonella enterica is required for the suppression of porcine alveolar macrophage cytokine expression.

    PubMed

    Pavlova, Barbora; Volf, Jiri; Ondrackova, Petra; Matiasovic, Jan; Stepanova, Hana; Crhanova, Magdalena; Karasova, Daniela; Faldyna, Martin; Rychlik, Ivan

    2011-01-24

    Genes localized at Salmonella pathogenicity island-1 (SPI-1) are involved in Salmonella enterica invasion of host non-professional phagocytes. Interestingly, in macrophages, SPI-1-encoded proteins, in addition to invasion, induce cell death via activation of caspase-1 which also cleaves proIL-1β and proIL-18, precursors of 2 proinflammatory cytokines. In this study we were therefore interested in whether SPI-1-encoded type III secretion system (T3SS) may influence proinflammatory response of macrophages. To test this hypothesis, we infected primary porcine alveolar macrophages with wild-type S. Typhimurium and S. Enteritidis and their isogenic SPI-1 deletion mutants. ΔSPI1 mutants of both serovars invaded approx. 5 times less efficiently than the wild-type strains and despite this, macrophages responded to the infection with ΔSPI1 mutants by increased expression of proinflammatory cytokines IL-1β, IL-8, TNFα, IL-23α and GM-CSF. Identical macrophage responses to that induced by the ΔSPI1 mutants were also observed to the infection with sipB but not the sipA mutant. The hilA mutant exhibited an intermediate phenotype between the ΔSPI1 mutant and the wild-type S. Enteritidis. Our results showed that the SPI-1-encoded T3SS is required not only for cell invasion but in macrophages also for the suppression of early proinflammatory cytokine expression.

  13. Genomic and evolutionary features of the SPI-1 type III secretion system that is present in Xanthomonas albilineans but is not essential for xylem colonization and symptom development of sugarcane leaf scald.

    PubMed

    Marguerettaz, Mélanie; Pieretti, Isabelle; Gayral, Philippe; Puig, Jérôme; Brin, Chrystelle; Cociancich, Stéphane; Poussier, Stéphane; Rott, Philippe; Royer, Monique

    2011-02-01

    Xanthomonas albilineans is the causal agent of sugarcane leaf scald. Interestingly, this bacterium, which is not known to be insect or animal associated, possesses a type III secretion system (T3SS) belonging to the injectisome family Salmonella pathogenicity island 1 (SPI-1). The T3SS SPI-1 of X. albilineans shares only low similarity with other available T3SS SPI-1 sequences. Screening of a collection of 128 plant-pathogenic bacteria revealed that this T3SS SPI-1 is present in only two species of Xanthomonas: X. albilineans and X. axonopodis pv. phaseoli. Inoculation of sugarcane with knockout mutants showed that this system is not required by X. albilineans to spread within xylem vessels and to cause disease symptoms. This result was confirmed by the absence of this T3SS SPI-1 in an X. albilineans strain isolated from diseased sugarcane. To investigate the importance of the T3SS SPI-1 during the life cycle of X. albilineans, we analyzed T3SS SPI-1 sequences from 11 strains spanning the genetic diversity of this species. No nonsense mutations or frameshifting indels were observed in any of these strains, suggesting that the T3SS SPI-1 system is maintained within the species X. albilineans. Evolutionary features of T3SS SPI-1 based on phylogenetic, recombination, and selection analyses are discussed in the context of the possible functional importance of T3SS SPI-1 in the ecology of X. albilineans.

  14. Variation between pathogenic serovars within Salmonella pathogenicity islands.

    PubMed

    Amavisit, P; Lightfoot, D; Browning, G F; Markham, P F

    2003-06-01

    Although four of the five Salmonella pathogenicity islands (SPIs) have been characterized in detail for Salmonella enterica serovar Typhimurium, and the fifth has been characterized for Salmonella enterica serovar Dublin, there have been limited studies to examine them in detail in a range of pathogenic serovars of S. enterica. The aim of this study was to examine these regions, shown to be crucial in virulence, in pathogenic serovars to identify any major deletions or insertions that may explain variation in virulence and provide further understanding of the elements involved in the evolution of these regions. Multiple strains of each of the 13 serovars were compared by Southern blot hybridization using a series of probes that together encompassed the full length of all five SPIs. With the exception of serovar Typhimurium, all strains of the same serovar were identical in all five SPIs. Those serovars that differed from serovar Typhimurium in SPI-1 to SPI-4 and from serovar Dublin in SPI-5 were examined in more detail in the variant regions by PCR, and restriction endonuclease digestion and/or DNA sequencing. While most variation in hybridization patterns was attributable to loss or gain of single restriction endonuclease cleavage sites, three regions, in SPI-1, SPI-3, and SPI-5, had differences due to major insertions or deletions. In SPI-1 the avrA gene was replaced by a 200-base fragment in three serovars, as reported previously. In SPI-5, two serovars had acquired an insertion with similarity to the pagJ and pagK genes between pipC and pipD. In SPI-3 the genes sugR and rhuM were deleted in most serovars and in some were replaced by sequences that were very similar to either the Escherichia coli fimbrial operon, flanked by two distinct insertion sequence elements, or to the E. coli retron phage PhiR73. The distribution of these differences suggests that there have been a number of relatively recent horizontal transfers of genes into S. enterica and that in some

  15. HilD-mediated transcriptional cross-talk between SPI-1 and SPI-2.

    PubMed

    Bustamante, Víctor H; Martínez, Luary C; Santana, Francisco J; Knodler, Leigh A; Steele-Mortimer, Olivia; Puente, José L

    2008-09-23

    The acquisition of new genetic traits by horizontal gene transfer and their incorporation into preexisting regulatory networks have been essential events in the evolution of bacterial pathogens. An example of successful assimilation of virulence traits is Salmonella enterica, which acquired, at distinct evolutionary times, Salmonella pathogenicity island 1 (SPI-1), required for efficient invasion of the intestinal epithelium and intestinal disease, and SPI-2, essential for Salmonella replication and survival within macrophages and the progression of a systemic infection. A positive regulatory cascade mainly composed of HilD, HilA, and InvF, encoded in SPI-1, controls the expression of SPI-1 genes, whereas the two-component regulatory system SsrA/B, encoded in SPI-2, controls expression of SPI-2 genes. In this study, we report a previously undescribed transcriptional cross-talk between SPI-1 and SPI-2, where the SPI-1-encoded regulator HilD is essential for the activation of both the SPI-1 and SPI-2 regulons but at different times during the stationary phase of growth in Luria-Bertani medium. Our data indicate that HilD counteracts the H-NS-mediated repression exerted on the OmpR-dependent activation of the ssrAB operon by specifically interacting with its regulatory region. In contrast, HilD is not required for SPI-2 regulon expression under the in vitro growth conditions that are thought to resemble the intracellular environment. Our results suggest that two independent SPI-2 activation pathways evolved to take advantage of the SPI-2-encoded information at different niches and, in consequence, in response to different growth conditions.

  16. Differences in Host Cell Invasion and Salmonella Pathogenicity Island 1 Expression between Salmonella enterica Serovar Paratyphi A and Nontyphoidal S. Typhimurium

    PubMed Central

    Elhadad, Dana; Desai, Prerak; Grassl, Guntram A.; McClelland, Michael; Rahav, Galia

    2016-01-01

    Active invasion into nonphagocytic host cells is central to Salmonella enterica pathogenicity and dependent on multiple genes within Salmonella pathogenicity island 1 (SPI-1). Here, we explored the invasion phenotype and the expression of SPI-1 in the typhoidal serovar S. Paratyphi A compared to that of the nontyphoidal serovar S. Typhimurium. We demonstrate that while S. Typhimurium is equally invasive under both aerobic and microaerobic conditions, S. Paratyphi A invades only following growth under microaerobic conditions. Transcriptome sequencing (RNA-Seq), reverse transcription-PCR (RT-PCR), Western blot, and secretome analyses established that S. Paratyphi A expresses much lower levels of SPI-1 genes and secretes lesser amounts of SPI-1 effector proteins than S. Typhimurium, especially under aerobic growth. Bypassing the native SPI-1 regulation by inducible expression of the SPI-1 activator, HilA, considerably elevated SPI-1 gene expression, host cell invasion, disruption of epithelial integrity, and induction of proinflammatory cytokine secretion by S. Paratyphi A but not by S. Typhimurium, suggesting that SPI-1 expression is naturally downregulated in S. Paratyphi A. Using streptomycin-treated mice, we were able to establish substantial intestinal colonization by S. Paratyphi A and showed moderately higher pathology and intestinal inflammation in mice infected with S. Paratyphi A overexpressing hilA. Collectively, our results reveal unexpected differences in SPI-1 expression between S. Paratyphi A and S. Typhimurium, indicate that S. Paratyphi A host cell invasion is suppressed under aerobic conditions, and suggest that lower invasion in aerobic sites and suppressed expression of immunogenic SPI-1 components contributes to the restrained inflammatory infection elicited by S. Paratyphi A. PMID:26857569

  17. Differences in Host Cell Invasion and Salmonella Pathogenicity Island 1 Expression between Salmonella enterica Serovar Paratyphi A and Nontyphoidal S. Typhimurium.

    PubMed

    Elhadad, Dana; Desai, Prerak; Grassl, Guntram A; McClelland, Michael; Rahav, Galia; Gal-Mor, Ohad

    2016-04-01

    Active invasion into nonphagocytic host cells is central to Salmonella enterica pathogenicity and dependent on multiple genes within Salmonella pathogenicity island 1 (SPI-1). Here, we explored the invasion phenotype and the expression of SPI-1 in the typhoidal serovarS Paratyphi A compared to that of the nontyphoidal serovarS Typhimurium. We demonstrate that while S. Typhimurium is equally invasive under both aerobic and microaerobic conditions, S. Paratyphi A invades only following growth under microaerobic conditions. Transcriptome sequencing (RNA-Seq), reverse transcription-PCR (RT-PCR), Western blot, and secretome analyses established that S. Paratyphi A expresses much lower levels of SPI-1 genes and secretes lesser amounts of SPI-1 effector proteins than S. Typhimurium, especially under aerobic growth. Bypassing the native SPI-1 regulation by inducible expression of the SPI-1 activator, HilA, considerably elevated SPI-1 gene expression, host cell invasion, disruption of epithelial integrity, and induction of proinflammatory cytokine secretion by S. Paratyphi A but not by S. Typhimurium, suggesting that SPI-1 expression is naturally downregulated inS Paratyphi A. Using streptomycin-treated mice, we were able to establish substantial intestinal colonization byS Paratyphi A and showed moderately higher pathology and intestinal inflammation in mice infected with S. Paratyphi A overexpressing hilA Collectively, our results reveal unexpected differences in SPI-1 expression between S. Paratyphi A andS Typhimurium, indicate that S. Paratyphi A host cell invasion is suppressed under aerobic conditions, and suggest that lower invasion in aerobic sites and suppressed expression of immunogenic SPI-1 components contributes to the restrained inflammatory infection elicited by S. Paratyphi A.

  18. Salmonella pathogenicity island 1 differentially modulates bacterial entry to dendritic and non-phagocytic cells

    PubMed Central

    Bueno, Susan M; Wozniak, Aniela; Leiva, Eduardo D; Riquelme, Sebastián A; Carreño, Leandro J; Hardt, Wolf-Dietrich; Riedel, Claudia A; Kalergis, Alexis M

    2010-01-01

    Salmonella enterica serovar Typhimurium can enter non-phagocytic cells, such as intestinal epithelial cells, by virtue of a Type Three Secretion System (TTSS) encoded in the Salmonella Pathogenicity Island 1 (SPI-1), which translocates bacterial effector molecules into the host cell. Salmonella can also be taken up by dendritic cells (DCs). Although the role of SPI-1 in non-phagocytic cell invasion is well established, its contribution to invasion of phagocytic cells has not been evaluated. Here, we have tested the invasive capacity of a S. Typhimurium strain lacking a key component of its TTSS-1 (ΔInvC) leading to defective translocation of SPI-1-encoded effectors. Whereas this mutant Salmonella strain was impaired for invasion of non-phagocytic cells, it was taken up by DCs at a significantly higher rate than wild-type Salmonella. Similar to wild-type Salmonella, the ΔInvC mutant strain retained the capacity to avoid antigen presentation to T cells. However, mice infected with the ΔInvC mutant strain showed higher survival rate and reduced organ colonization. Our data suggest that, besides promoting phagocytosis by non-phagocytic cells, SPI-1 modulates the number of bacteria that enters DCs. The SPI-1 could be considered not only as an inducer of epithelial cell invasion but as a controller of DC entry. PMID:20201987

  19. LsrR-mediated quorum sensing controls invasiveness of Salmonella typhimurium by regulating SPI-1 and flagella genes.

    PubMed

    Choi, Jeongjoon; Shin, Dongwoo; Kim, Minjeong; Park, Joowon; Lim, Sangyong; Ryu, Sangryeol

    2012-01-01

    Bacterial cell-to-cell communication, termed quorum sensing (QS), controls bacterial behavior by using various signal molecules. Despite the fact that the LuxS/autoinducer-2 (AI-2) QS system is necessary for normal expression of Salmonella pathogenicity island-1 (SPI-1), the mechanism remains unknown. Here, we report that the LsrR protein, a transcriptional regulator known to be involved in LuxS/AI-2-mediated QS, is also associated with the regulation of SPI-1-mediated Salmonella virulence. We determined that LsrR negatively controls SPI-1 and flagella gene expressions. As phosphorylated AI-2 binds to and inactivates LsrR, LsrR remains active and decreases expression of SPI-1 and flagella genes in the luxS mutant. The reduced expression of those genes resulted in impaired invasion of Salmonella into epithelial cells. Expression of SPI-1 and flagella genes was also reduced by overexpression of the LsrR regulator from a plasmid, but was relieved by exogenous AI-2, which binds to and inactivates LsrR. These results imply that LsrR plays an important role in selecting infectious niche of Salmonella in QS dependent mode.

  20. Protection of epithelial cells from Salmonella enterica serovar Enteritidis invasion by antibodies against the SPI-1 type III secretion system.

    PubMed

    Desin, Taseen S; Mickael, Claudia S; Lam, Po-King S; Potter, Andrew A; Köster, Wolfgang

    2010-06-01

    Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) is one of the major causes of bacterial food-borne illness in humans. During the course of infection, Salmonella Enteritidis uses 2 type III secretion systems (T3SS), one of which is encoded on Salmonella pathogenicity island 1 (SPI-1). SPI-1 plays a major role in the invasion process. In the present study, we evaluated the effect of sera against the SPI-1 T3SS components on invasion in vitro using polarized human intestinal epithelial cells (Caco-2). Antisera to SipD protected Caco-2 cells against entry of wild-type Salmonella Enteritidis. On the other hand, sera against InvG, PrgI, SipA, SipC, SopB, SopE, and SopE2 did not affect Salmonella Enteritidis entry. To illustrate the specificity of anti-SipD mediated inhibition, SipD-specific antibodies were depleted from the serum. Antiserum depleted of SipD-specific antibodies lost its capacity to inhibit Salmonella Enteritidis entry. Thus, we demonstrate for the first time that antibodies against the SPI-1 needle tip protein (SipD) inhibit Salmonella Enteritidis invasion and that the SipD protein may be an important target in blocking SPI-1 mediated virulence of Salmonella Enteritidis.

  1. Evaluation of Salmonella enterica serovar Enteritidis pathogenicity island-1 proteins as vaccine candidates against S. Enteritidis challenge in chickens.

    PubMed

    Desin, Taseen S; Wisner, Amanda L S; Lam, Po-King S; Berberov, Emil; Mickael, Claudia S; Potter, Andrew A; Köster, Wolfgang

    2011-03-24

    Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major cause of gastrointestinal disease in humans worldwide, which mainly results from the consumption of contaminated poultry meat and eggs. Vaccination of chickens is an important strategy to lower the prevalence of Salmonella in poultry flocks. The S. Enteritidis type 3 secretion system (T3SS) encoded on Salmonella pathogenicity island-1 (SPI-1) is an important virulence factor that plays a role in invasion and systemic spread in chickens. In this manuscript, we evaluated the efficacy of SPI-1 proteins as vaccine candidates for protection against S. Enteritidis oral challenge. Our results demonstrate for the first time that SPI-1 T3SS proteins elicit antigen specific IgG antibody responses in chickens. In one study we show that vaccination with the aforementioned proteins reduces the levels of S. Enteritidis in the liver, but not in the spleen and cecal contents of chickens. However, a second study shows that vaccination of hens with SPI-1 proteins using a seeder model of infection does not affect the levels of S. Enteritidis in the cecal contents or internal organs of progeny obtained from these hens. Hence, the SPI-1 proteins, in conjunction with other proteins, may form important components of subunit vaccines used for protection against colonization by S. Enteritidis in poultry. PMID:20888713

  2. Evaluation of Salmonella enterica serovar Enteritidis pathogenicity island-1 proteins as vaccine candidates against S. Enteritidis challenge in chickens.

    PubMed

    Desin, Taseen S; Wisner, Amanda L S; Lam, Po-King S; Berberov, Emil; Mickael, Claudia S; Potter, Andrew A; Köster, Wolfgang

    2011-03-24

    Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major cause of gastrointestinal disease in humans worldwide, which mainly results from the consumption of contaminated poultry meat and eggs. Vaccination of chickens is an important strategy to lower the prevalence of Salmonella in poultry flocks. The S. Enteritidis type 3 secretion system (T3SS) encoded on Salmonella pathogenicity island-1 (SPI-1) is an important virulence factor that plays a role in invasion and systemic spread in chickens. In this manuscript, we evaluated the efficacy of SPI-1 proteins as vaccine candidates for protection against S. Enteritidis oral challenge. Our results demonstrate for the first time that SPI-1 T3SS proteins elicit antigen specific IgG antibody responses in chickens. In one study we show that vaccination with the aforementioned proteins reduces the levels of S. Enteritidis in the liver, but not in the spleen and cecal contents of chickens. However, a second study shows that vaccination of hens with SPI-1 proteins using a seeder model of infection does not affect the levels of S. Enteritidis in the cecal contents or internal organs of progeny obtained from these hens. Hence, the SPI-1 proteins, in conjunction with other proteins, may form important components of subunit vaccines used for protection against colonization by S. Enteritidis in poultry.

  3. Pathogenicity islands in bacterial pathogenesis.

    PubMed

    Schmidt, Herbert; Hensel, Michael

    2004-01-01

    In this review, we focus on a group of mobile genetic elements designated pathogenicity islands (PAI). These elements play a pivotal role in the virulence of bacterial pathogens of humans and are also essential for virulence in pathogens of animals and plants. Characteristic molecular features of PAI of important human pathogens and their role in pathogenesis are described. The availability of a large number of genome sequences of pathogenic bacteria and their benign relatives currently offers a unique opportunity for the identification of novel pathogen-specific genomic islands. However, this knowledge has to be complemented by improved model systems for the analysis of virulence functions of bacterial pathogens. PAI apparently have been acquired during the speciation of pathogens from their nonpathogenic or environmental ancestors. The acquisition of PAI not only is an ancient evolutionary event that led to the appearance of bacterial pathogens on a timescale of millions of years but also may represent a mechanism that contributes to the appearance of new pathogens within a human life span. The acquisition of knowledge about PAI, their structure, their mobility, and the pathogenicity factors they encode not only is helpful in gaining a better understanding of bacterial evolution and interactions of pathogens with eukaryotic host cells but also may have important practical implications such as providing delivery systems for vaccination, tools for cell biology, and tools for the development of new strategies for therapy of bacterial infections.

  4. Pathogenicity Islands in Bacterial Pathogenesis

    PubMed Central

    Schmidt, Herbert; Hensel, Michael

    2004-01-01

    In this review, we focus on a group of mobile genetic elements designated pathogenicity islands (PAI). These elements play a pivotal role in the virulence of bacterial pathogens of humans and are also essential for virulence in pathogens of animals and plants. Characteristic molecular features of PAI of important human pathogens and their role in pathogenesis are described. The availability of a large number of genome sequences of pathogenic bacteria and their benign relatives currently offers a unique opportunity for the identification of novel pathogen-specific genomic islands. However, this knowledge has to be complemented by improved model systems for the analysis of virulence functions of bacterial pathogens. PAI apparently have been acquired during the speciation of pathogens from their nonpathogenic or environmental ancestors. The acquisition of PAI not only is an ancient evolutionary event that led to the appearance of bacterial pathogens on a timescale of millions of years but also may represent a mechanism that contributes to the appearance of new pathogens within a human life span. The acquisition of knowledge about PAI, their structure, their mobility, and the pathogenicity factors they encode not only is helpful in gaining a better understanding of bacterial evolution and interactions of pathogens with eukaryotic host cells but also may have important practical implications such as providing delivery systems for vaccination, tools for cell biology, and tools for the development of new strategies for therapy of bacterial infections. PMID:14726454

  5. Salmonella effectors within a single pathogenicity island are differentially expressed and translocated by separate type III secretion systems.

    PubMed

    Knodler, Leigh A; Celli, Jean; Hardt, Wolf-Dietrich; Vallance, Bruce A; Yip, Calvin; Finlay, B Brett

    2002-03-01

    Pathogenicity islands (PAIs) are large DNA segments in the genomes of bacterial pathogens that encode virulence factors. Five PAIs have been identified in the Gram-negative bacterium Salmonella enterica. Two of these PAIs, Salmonella pathogenicity island (SPI)-1 and SPI-2, encode type III secretion systems (TTSS), which are essential virulence determinants. These 'molecular syringes' inject effectors directly into the host cell, whereupon they manipulate host cell functions. These effectors are either encoded with their respective TTSS or scattered elsewhere on the Salmonella chromosome. Importantly, SPI-1 and SPI-2 are expressed under distinct environmental conditions: SPI-1 is induced upon initial contact with the host cell, whereas SPI-2 is induced intracellularly. Here, we demonstrate that a single PAI, in this case SPI-5, can encode effectors that are induced by distinct regulatory cues and targeted to different TTSS. SPI-5 encodes the SPI-1 TTSS translocated effector, SigD/SopB. In contrast, we report that the adjacently encoded effector PipB is part of the SPI-2 regulon. PipB is translocated by the SPI-2 TTSS to the Salmonella-containing vacuole and Salmonella-induced filaments. We also show that regions of SPI-5 are not conserved in all Salmonella spp. Although sigD/sopB is present in all Salmonella spp., pipB is not found in Salmonella bongori, which also lacks a functional SPI-2 TTSS. Thus, we demonstrate a functional and regulatory cross-talk between three chromosomal PAIs, SPI-1, SPI-2 and SPI-5, which has significant implications for the evolution and role of PAIs in bacterial pathogenesis.

  6. Essential role of spi-1-like (spi-1l) in zebrafish myeloid cell differentiation.

    PubMed

    Bukrinsky, Alex; Griffin, Kevin J P; Zhao, Yan; Lin, Shuo; Banerjee, Utpal

    2009-02-26

    The ETS protein Spi-1/Pu.1 plays a pivotal and widespread role throughout hematopoiesis in many species. This study describes the identification, characterization, and functional analysis of a new zebrafish spi transcription factor spi-1-like (spi-1l) that is expressed in primitive myeloid cells, erythro-myelo progenitor cells, and in the adult kidney. Spi-1l functions genetically downstream of etsrp, scl, and spi-1/pu.1 in myeloid differentiation. Spi-1l is coexpressed in a subset of spi-1/pu.1 cells and its function is necessary and sufficient for macrophage and granulocyte differentiation. These results establish a critical role for spi-1l in zebrafish myeloid cell differentiation.

  7. Salmonella translocates across an in vitro M cell model independently of SPI-1 and SPI-2.

    PubMed

    Martinez-Argudo, Isabel; Jepson, Mark A

    2008-12-01

    We have used an in vitro model of intestinal M cells to examine the mechanisms by which Salmonella enterica translocates across these specialized cells, which constitute a primary site of infection of the mammalian host. S. enterica can invade cultured cells by deploying a type III secretion system (TTSS) encoded within Salmonella pathogenicity island 1 (SPI-1) to translocate effector proteins into the host cell cytoplasm that trigger cellular responses, including prominent cytoskeletal rearrangements. After Salmonella enters the host cell, a second TTSS encoded in SPI-2 modulates intracellular trafficking and enables the bacteria to replicate within a modified vacuolar compartment. Within the host intestine, specialized antigen-sampling M cells, which reside in the epithelium overlying lymphoid tissues in the gut, are a preferential site of Salmonella invasion. The mechanisms of infection of M cells remain poorly defined and it is not known whether either SPI-1 or SPI-2 is required for infection of these cells. To address these questions we have employed an in vitro M cell model involving co-culture of polarized Caco-2 intestinal epithelial cells with Raji B cells. S. enterica serovar Typhimurium translocated across Caco-2/Raji co-cultures to a much greater extent than they cross native Caco-2 cell monolayers. Salmonella translocation was greatly reduced by heat treatment or fixation, suggesting that processes distinct from the sampling of inert particles are the main determinants of bacterial translocation. Translocation across both mono-cultured and co-cultured Caco-2 cells was partially inhibited by treatment with the dynamin inhibitor dynasore, but resistant to EIPA, an inhibitor of macropinocytosis. There was no difference between the abilities of wild-type Salmonella Typhimurium and mutants lacking multiple SPI-1 effectors to translocate across the M cell model, although the SPI-1 effector mutants were somewhat attenuated for translocation across native Caco

  8. Pathogenicity islands and the evolution of bacterial pathogens.

    PubMed

    Lee, C A

    1996-01-01

    The term pathogenicity island has been used to refer to large chromosomal regions in pathogenic bacteria that encode virulence genes. This article reviews the recent history of this term and considers what characteristics define a pathogenicity island. It appears that pathogenicity islands can confer complex virulence phenotypes and were acquired by bacteria from unrelated organisms, leading to interesting hypotheses about how bacterial pathogens evolved. It is likely that mechanisms that generate pathogenicity islands continue to operate and may contribute to the emergence of bacterial pathogens with new virulence properties.

  9. Pathogenicity islands and the evolution of microbes.

    PubMed

    Hacker, J; Kaper, J B

    2000-01-01

    Virulence factors of pathogenic bacteria (adhesins, toxins, invasins, protein secretion systems, iron uptake systems, and others) may be encoded by particular regions of the prokaryotic genome termed pathogenicity islands. Pathogenicity islands were first described in human pathogens of the species Escherichia coli, but have recently been found in the genomes of various pathogens of humans, animals, and plants. Pathogenicity islands comprise large genomic regions [10-200 kilobases (kb) in size] that are present on the genomes of pathogenic strains but absent from the genomes of nonpathogenic members of the same or related species. The finding that the G+C content of pathogenicity islands often differs from that of the rest of the genome, the presence of direct repeats at their ends, the association of pathogenicity islands with transfer RNA genes, the presence of integrase determinants and other mobility loci, and their genetic instability argue for the generation of pathogenicity islands by horizontal gene transfer, a process that is well known to contribute to microbial evolution. In this article we review these and other aspects of pathogenicity islands and discuss the concept that they represent a subclass of genomic islands. Genomic islands are present in the majority of genomes of pathogenic as well as nonpathogenic bacteria and may encode accessory functions which have been previously spread among bacterial populations.

  10. The effect of cell growth phase on the regulatory cross-talk between flagellar and Spi1 virulence gene expression.

    PubMed

    Mouslim, Chakib; Hughes, Kelly T

    2014-03-01

    The flagellar regulon controls Salmonella biofilm formation, virulence gene expression and the production of the major surface antigen present on the cell surface: flagellin. At the top of a flagellar regulatory hierarchy is the master operon, flhDC, which encodes the FlhD₄C₂ transcriptional complex required for the expression of flagellar, chemotaxis and Salmonella pathogenicity island 1 (Spi1) genes. Of six potential transcriptional start-sites within the flhDC promoter region, only two, P1(flhDC) and P5(flhDC), were functional in a wild-type background, while P6(flhDC) was functional in the absence of CRP. These promoters are transcribed differentially to control either flagellar or Spi1 virulent gene expression at different stages of cell growth. Transcription from P1(flhDC) initiates flagellar assembly and a negative autoregulatory loop through FlhD₄C₂-dependent transcription of the rflM gene, which encodes a repressor of flhDC transcription. Transcription from P1(flhDC) also initiates transcription of the Spi1 regulatory gene, hilD, whose product, in addition to activating Spi1 genes, also activates transcription of the flhDC P5 promoter later in the cell growth phase. The regulators of flhDC transcription (RcsB, LrhA, RflM, HilD, SlyA and RtsB) also exert their control at different stages of the cell growth phase and are also subjected to cell growth phase control. This dynamic of flhDC transcription separates the roles of FlhD₄C₂ transcriptional activation into an early cell growth phase role for flagellar production from a late cell growth phase role in virulence gene expression.

  11. Transcriptional and Post-Transcriptional Modulation of SPI1 and SPI2 Expression by ppGpp, RpoS and DksA in Salmonella enterica sv Typhimurium.

    PubMed

    Rice, Christopher J; Ramachandran, Vinoy K; Shearer, Neil; Thompson, Arthur

    2015-01-01

    The expression of genes within Salmonella Pathogenicity Islands 1 and 2 (SPI1, SPI2) is required to facilitate invasion and intracellular replication respectively of S. Typhimurium in host cell lines. Control of their expression is complex and occurs via a variety of factors operating at transcriptional and post-transcriptional levels in response to the environmental stimuli found within the host. Several of the factors that modulate SPI1 and SPI2 expression are involved in the redistribution or modification of RNA polymerase (RNAP) specificity. These factors include the bacterial alarmone, ppGpp, the alternative sigma factor, RpoS, and the RNAP accessory protein, DksA. In this report we show not only how these three factors modulate SPI1 and SPI2 expression but also how they contribute to the 'phased' expression of SPI1 and SPI2 during progress through late-log and stationary phase in aerobic rich broth culture conditions. In addition, we demonstrate that the expression of at least one SPI1-encoded protein, SipC is subject to DksA-dependent post-transcriptional control.

  12. Transcriptional and Post-Transcriptional Modulation of SPI1 and SPI2 Expression by ppGpp, RpoS and DksA in Salmonella enterica sv Typhimurium

    PubMed Central

    Rice, Christopher J.; Ramachandran, Vinoy K.; Shearer, Neil; Thompson, Arthur

    2015-01-01

    The expression of genes within Salmonella Pathogenicity Islands 1 and 2 (SPI1, SPI2) is required to facilitate invasion and intracellular replication respectively of S. Typhimurium in host cell lines. Control of their expression is complex and occurs via a variety of factors operating at transcriptional and post-transcriptional levels in response to the environmental stimuli found within the host. Several of the factors that modulate SPI1 and SPI2 expression are involved in the redistribution or modification of RNA polymerase (RNAP) specificity. These factors include the bacterial alarmone, ppGpp, the alternative sigma factor, RpoS, and the RNAP accessory protein, DksA. In this report we show not only how these three factors modulate SPI1 and SPI2 expression but also how they contribute to the ‘phased’ expression of SPI1 and SPI2 during progress through late-log and stationary phase in aerobic rich broth culture conditions. In addition, we demonstrate that the expression of at least one SPI1-encoded protein, SipC is subject to DksA-dependent post-transcriptional control. PMID:26039089

  13. Characterization of SprA, an AraC-like transcriptional regulator encoded within the Salmonella typhimurium pathogenicity island 1.

    PubMed

    Eichelberg, K; Hardt, W D; Galán, J E

    1999-07-01

    Pathogenicity island 1 (SPI-1) located at centisome 63 of the Salmonella chromosome encodes a type III protein secretion system that is essential for its pathogenicity. The translocation of effector proteins through this system results in the stimulation of signalling events, leading to actin cytoskeletal rearrangements and nuclear responses. These cellular responses ultimately lead to bacterial uptake, production of proinflammatory cytokines in non-phagocytic cells and the initiation of programmed cell death in macrophages. The regulation of expression of components and substrates of this type III secretion system is complex and involves the activity of several specific transcriptional regulatory proteins encoded within SPI-1. Here, we describe two additional regulatory proteins, SprA and SprB, which are encoded within SPI-1. SprA and SprB exhibit significant sequence similarity to the AraC/XylS and the LuxR/UhaP family of transcriptional regulatory proteins respectively. Insertion mutations in sprA and sprB did not significantly affect the transcription of invasion-associated genes and, consequently, did not affect the ability of Salmonella typhimurium to gain access into host cells. However, expression of sprA from an inducible heterologous promoter resulted in increased expression of genes associated with the centisome 63 type III secretion system and increased the ability of S. typhimurium to enter into host cells. Further analysis demonstrated that SprA acts either upstream or at the same level as HilA in the SPI-1 transcriptional regulatory cascade.

  14. Pathogenicity island mobility and gene content.

    SciTech Connect

    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.

  15. Regulation of Salmonella enterica pathogenicity island 1 by DNA adenine methylation.

    PubMed

    López-Garrido, Javier; Casadesús, Josep

    2010-03-01

    DNA adenine methylase (Dam(-)) mutants of Salmonella enterica are attenuated in the mouse model and present multiple virulence-related defects. Impaired interaction of Salmonella Dam(-) mutants with the intestinal epithelium has been tentatively correlated with reduced secretion of pathogenicity island 1 (SPI-1) effectors. In this study, we show that S. enterica Dam(-) mutants contain lowered levels of the SPI-1 transcriptional regulators HilA, HilC, HilD, and InvF. Epistasis analysis indicates that Dam-dependent regulation of SPI-1 requires HilD, while HilA, HilC, and InvF are dispensable. A transcriptional hilDlac fusion is expressed at similar levels in Dam(+) and Dam(-) hosts. However, lower levels of hilD mRNA are found in a Dam(-) background, thus providing unsuspected evidence that Dam methylation might exert post-transcriptional regulation of hilD expression. This hypothesis is supported by the following lines of evidence: (i) lowered levels of hilD mRNA are found in Salmonella Dam(-) mutants when hilD is transcribed from a heterologous promoter; (ii) increased hilD mRNA turnover is observed in Dam(-) mutants; (iii) lack of the Hfq RNA chaperone enhances hilD mRNA instability in Dam(-) mutants; and (iv) lack of the RNA degradosome components polynucleotide phosphorylase and ribonuclease E suppresses hilD mRNA instability in a Dam(-) background. Our report of Dam-dependent control of hilD mRNA stability suggests that DNA adenine methylation plays hitherto unknown roles in post-transcriptional control of gene expression.

  16. SPI1 defective mutants of Salmonella enterica induce cross-protective immunity in chickens against challenge with serovars Typhimurium and Enteritidis.

    PubMed

    Matulova, Marta; Havlickova, Hana; Sisak, Frantisek; Babak, Vladimir; Rychlik, Ivan

    2013-06-28

    In this study we were interested in the serovar cross-protection potential of Salmonella Pathogenicity Island 1 (SPI1) attenuated vaccine strains of Salmonella enterica serovars Enteritidis and Typhimurium and immune response of vaccinated and naive chickens to Salmonella infection. The immune response was characterized by real time PCR quantifying transcripts of interleukins IL1β, IL17, IL22, interferon gamma (IFNγ), inducible NO synthase (iNOS), immunoglobulins IgM, IgA, IgY and Ig light chain, and six genes of acute phase response including avidin, serum amyloid A, extracellular fatty acid-binding protein (Ex-FABP), immune responsive gene 1, chemokine AH221 and trappin-6. Vaccination with SPI1 mutants of both serovars protected chickens against Salmonella infection, independent of the serovar used for the challenge and the time post infection. However, expressions of all interleukins, iNOS and Ex-FABP showed that protection against homologous serovars was significantly higher than against heterologous serovars after intravenous challenge at 4 days post infection. The vaccination with a mixture of S. Enteritidis and S. Typhimurium SPI1 mutants induced an intermediate protection against challenge with both serovars, i.e. the mixed vaccine provided an additional protective effect when compared with the chickens vaccinated with a vaccine formed by only a single Salmonella serovar. PMID:23684831

  17. FliZ regulates expression of the Salmonella pathogenicity island 1 invasion locus by controlling HilD protein activity in Salmonella enterica serovar typhimurium.

    PubMed

    Chubiz, Jessica E Cott; Golubeva, Yekaterina A; Lin, Dongxia; Miller, Lucas D; Slauch, James M

    2010-12-01

    A prerequisite for Salmonella enterica to cause both intestinal and systemic disease is the direct injection of effector proteins into host intestinal epithelial cells via a type three secretion system (T3SS); the T3SS genes are carried on Salmonella pathogenicity island 1 (SPI1). These effector proteins induce inflammatory diarrhea and bacterial invasion. Expression of the SPI1 T3SS is tightly regulated in response to environmental signals through a variety of global regulatory systems. We have previously shown that three AraC-like regulators, HilD, HilC, and RtsA, act in a complex feed-forward regulatory loop to control the expression of the hilA gene, which encodes the direct regulator of the SPI1 structural genes. In this work, we characterize a major positive regulator of this system, the flagellar protein FliZ. Through genetic and biochemical analyses, we show that FliZ posttranslationally controls HilD to positively regulate hilA expression. This mechanism is independent of other flagellar components and is not mediated through the negative regulator HilE or through FliZ-mediated RpoS regulation. We demonstrate that FliZ controls HilD protein activity and not stability. FliZ regulates HilD in the absence of Lon protease, previously shown to degrade HilD. Indeed, it appears that FliZ, rather than HilD, is the most relevant target of Lon as it relates to SPI1 expression. Mutants lacking FliZ are significantly attenuated in their ability to colonize the intestine but are unaffected during systemic infection. The intestinal attenuation is partially dependent on SPI1, but FliZ has additional pleiotropic effects.

  18. Integration of a complex regulatory cascade involving the SirA/BarA and Csr global regulatory systems that controls expression of the Salmonella SPI-1 and SPI-2 virulence regulons through HilD.

    PubMed

    Martínez, Luary C; Yakhnin, Helen; Camacho, Martha I; Georgellis, Dimitris; Babitzke, Paul; Puente, José L; Bustamante, Víctor H

    2011-06-01

    Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2) play key roles in the pathogenesis of Salmonella enterica. Previously, we showed that when Salmonella grows in Luria-Bertani medium, HilD, encoded in SPI-1, first induces the expression of hilA, located in SPI-1, and subsequently of the ssrAB operon, located in SPI-2. These genes code for HilA and the SsrA/B two-component system, the positive regulators of the SPI-1 and SPI-2 regulons respectively. In this study, we demonstrate that CsrA, a global regulatory RNA binding protein, post-transcriptionally regulates hilD expression by directly binding near the Shine-Dalgarno and translation initiation codon sequences of the hilD mRNA, preventing its translation and leading to its accelerated turnover. Negative regulation is counteracted by the global SirA/BarA two-component system, which directly activates the expression of CsrB and CsrC, two non-coding regulatory RNAs that sequester CsrA, thereby preventing it from binding to its target mRNAs. Our results illustrate the integration of global and specific regulators into a multifactorial regulatory cascade controlling the expression of virulence genes acquired by horizontal transfer events.

  19. Flagellin Is Required for Host Cell Invasion and Normal Salmonella Pathogenicity Island 1 Expression by Salmonella enterica Serovar Paratyphi A.

    PubMed

    Elhadad, Dana; Desai, Prerak; Rahav, Galia; McClelland, Michael; Gal-Mor, Ohad

    2015-09-01

    Salmonella enterica serovar Paratyphi A is a human-specific serovar that, together with Salmonella enterica serovar Typhi and Salmonella enterica serovar Sendai, causes enteric fever. Unlike the nontyphoidal Salmonella enterica serovar Typhimurium, the genomes of S. Typhi and S. Paratyphi A are characterized by inactivation of multiple genes, including in the flagellum-chemotaxis pathway. Here, we explored the motility phenotype of S. Paratyphi A and the role of flagellin in key virulence-associated phenotypes. Motility studies established that the human-adapted typhoidal S. Typhi, S. Paratyphi A, and S. Sendai are all noticeably less motile than S. Typhimurium, and comparative transcriptome sequencing (RNA-Seq) showed that in S. Paratyphi A, the entire motility-chemotaxis regulon is expressed at significantly lowers levels than in S. Typhimurium. Nevertheless, S. Paratyphi A, like S. Typhimurium, requires a functional flagellum for epithelial cell invasion and macrophage uptake, probably in a motility-independent mechanism. In contrast, flagella were found to be dispensable for host cell adhesion. Moreover, we demonstrate that in S. Paratyphi A, but not in S. Typhimurium, the lack of flagellin results in increased transcription of the flagellar and the Salmonella pathogenicity island 1 (SPI-1) regulons in a FliZ-dependent manner and in oversecretion of SPI-1 effectors via type three secretion system 1. Collectively, these results suggest a novel regulatory linkage between flagellin and SPI-1 in S. Paratyphi A that does not occur in S. Typhimurium and demonstrate curious distinctions in motility and the expression of the flagellum-chemotaxis regulon between these clinically relevant pathogens.

  20. Flagellin Is Required for Host Cell Invasion and Normal Salmonella Pathogenicity Island 1 Expression by Salmonella enterica Serovar Paratyphi A

    PubMed Central

    Elhadad, Dana; Desai, Prerak; Rahav, Galia; McClelland, Michael

    2015-01-01

    Salmonella enterica serovar Paratyphi A is a human-specific serovar that, together with Salmonella enterica serovar Typhi and Salmonella enterica serovar Sendai, causes enteric fever. Unlike the nontyphoidal Salmonella enterica serovar Typhimurium, the genomes of S. Typhi and S. Paratyphi A are characterized by inactivation of multiple genes, including in the flagellum-chemotaxis pathway. Here, we explored the motility phenotype of S. Paratyphi A and the role of flagellin in key virulence-associated phenotypes. Motility studies established that the human-adapted typhoidal S. Typhi, S. Paratyphi A, and S. Sendai are all noticeably less motile than S. Typhimurium, and comparative transcriptome sequencing (RNA-Seq) showed that in S. Paratyphi A, the entire motility-chemotaxis regulon is expressed at significantly lowers levels than in S. Typhimurium. Nevertheless, S. Paratyphi A, like S. Typhimurium, requires a functional flagellum for epithelial cell invasion and macrophage uptake, probably in a motility-independent mechanism. In contrast, flagella were found to be dispensable for host cell adhesion. Moreover, we demonstrate that in S. Paratyphi A, but not in S. Typhimurium, the lack of flagellin results in increased transcription of the flagellar and the Salmonella pathogenicity island 1 (SPI-1) regulons in a FliZ-dependent manner and in oversecretion of SPI-1 effectors via type three secretion system 1. Collectively, these results suggest a novel regulatory linkage between flagellin and SPI-1 in S. Paratyphi A that does not occur in S. Typhimurium and demonstrate curious distinctions in motility and the expression of the flagellum-chemotaxis regulon between these clinically relevant pathogens. PMID:26056383

  1. The chaperone binding domain of SopE inhibits transport via flagellar and SPI-1 TTSS in the absence of InvB.

    PubMed

    Ehrbar, Kristin; Winnen, Brit; Hardt, Wolf-Dietrich

    2006-01-01

    Type III secretion systems (TTSS) are used by many Gram-negative pathogens for transporting effector proteins into eukaryotic host cells. Two modes of type III effector protein transport can be distinguished: transport into the surrounding medium (secretion) and cell-contact induced injection of effector proteins directly into the host cell cytosol (translocation). Two domains within the N-terminal regions of effector proteins determine the mode of transport. The amino terminal approximately 20 amino acids (N-terminal secretion signal, NSS) mediate secretion. In contrast, translocation generally requires the NSS, the adjacent approximately 100 amino acids (chaperone binding domain, CBD) and binding of the cognate chaperone to this CBD. TTSS are phylogenetically related to flagellar systems. Because both systems are expressed in Salmonella Typhimurium, correct effector protein transport involves at least two decisions: transport via the Salmonella pathogenicity island 1 (SPI-1) but not the flagellar TTSS (= specificity) and translocation into the host cell instead of secretion into the surrounding media (= transport mode). The mechanisms guiding these decisions are poorly understood. We have studied the S. Typhimurium effector protein SopE, which is specifically transported via the SPI-1 TTSS. Secretion and translocation strictly require the cognate chaperone InvB. Alanine replacement of amino acids 30-42 (and to some extent 44-54) abolished tight InvB binding, abolished translocation into the host cell and led to secretion of SopE via both, the flagellar and the SPI-1 TTSS. In clear contrast to wild-type SopE, secretion of SopE(Ala30-42) and SopE(Ala44-54) via the SPI-1 and the flagellar export system did not require InvB. These data reveal a novel function of the CBD: the CBD inhibits secretion of wild-type SopE via the flagellar and the SPI-1 TTSS in the absence of the chaperone InvB. Our data provide new insights into mechanisms ensuring specific effector

  2. Pathogenicity islands and virulence evolution in Listeria.

    PubMed

    Vázquez-Boland, J A; Domínguez-Bernal, G; González-Zorn, B; Kreft, J; Goebel, W

    2001-06-01

    As in other bacterial pathogens, the virulence determinants of Listeria species are clustered in genomic islands scattered along the chromosome. This review summarizes current knowledge about the structure, distribution and role in pathogenesis of Listeria virulence loci. Hypotheses about the mode of acquisition and evolution of these loci in this group of Gram-positive bacteria are presented and discussed.

  3. Type III secretion systems and pathogenicity islands.

    PubMed

    Winstanley, C; Hart, C A

    2001-02-01

    Some bacterial pathogens have evolved by acquiring pathogenicity islands (PIs), which are clusters of genes encoding virulence traits. PIs encoding the secretion of effector molecules via type III secretion (TTS) systems have been discovered in several gram-negative pathogens. TTS systems are involved in contact-dependent secretion of virulence factors and can facilitate delivery of toxins directly into target cells. The expanding list of bacteria found to contain clusters of TTS genes includes members of the genera Yersinia, Salmonella, Shigella, Escherichia, Pseudomonas, Bordetella, Burkholderia, Chlamydia and a number of plant pathogens or symbionts. This review discusses the current knowledge of the role of TTS PIs in pathogenicity, the genetic organisation and evolution of such systems,and the potential for using TTS systems as targets for novel treatments.

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

    PubMed Central

    Bouyioukos, Costas; Reverchon, Sylvie; Képès, François

    2016-01-01

    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. PMID:27302835

  5. Promiscuous Pathogenicity Islands and Phylogeny of Pathogenic Streptomyces spp.

    PubMed

    Zhang, Yucheng; Bignell, Dawn R D; Zuo, Ran; Fan, Qiurong; Huguet-Tapia, Jose C; Ding, Yousong; Loria, Rosemary

    2016-08-01

    Approximately 10 Streptomyces species cause disease on underground plant structures. The most economically important of these is potato scab, and the most studied of these pathogens is Streptomyces scabiei (syn. S. scabies). The main pathogenicity determinant of scab-causing Streptomyces species is a nitrated diketopiperazine, known as thaxtomin A (ThxA). In the pathogenic species Streptomyces turgidiscabies, ThxA biosynthetic genes reside on a mobile pathogenicity island (PAI). However, the mobilization of PAIs in other Streptomyces species remains uncharacterized. Here, we investigated the mobilization of the PAI of S. scabiei 87-22. Based on whole genome sequences, we inferred the evolutionary relationships of pathogenic Streptomyces species and discovered that Streptomyces sp. strain 96-12, a novel pathogenic species isolated from potatoes in Egypt, was phylogenetically grouped with nonpathogenic species rather than with known pathogenic species. We also found that Streptomyces sp. strain 96-12 contains a PAI that is almost identical to the PAI in S. scabiei 87-22, despite significant differences in their genome sequences. This suggested direct or indirect in vivo mobilization of the PAI between S. scabiei and nonpathogenic Streptomyces species. To test whether the S. scabiei 87-22 PAI could, indeed, be mobilized, S. scabiei 87-22 deletion mutants containing antibiotic resistance markers in the PAI were mated with Streptomyces diastatochromogenes, a nonpathogenic species. The PAI of S. scabiei was site-specifically inserted into the aviX1 gene of S. diastatochromogenes and conferred pathogenicity in radish seedling assays. Our results demonstrated that S. scabiei, the earliest described Streptomyces pathogen, could be the source of a PAI responsible for the emergence of novel pathogenic species. PMID:27502745

  6. Salmonella enterica serovar typhimurium pathogenicity island 1-encoded type III secretion system translocases mediate intimate attachment to nonphagocytic cells.

    PubMed

    Lara-Tejero, María; Galán, Jorge E

    2009-07-01

    Delivery of bacterial proteins into mammalian cells by type III secretion systems (TTSS) is thought to require the intimate association of bacteria with target cells. The molecular bases of this intimate association appear to be different in different bacteria involving TTSS components, as well as surface determinants not associated with TTSS. We show here that the protein translocases SipB, SipC, and SipD of the Salmonella enterica serovar Typhimurium pathogenicity island 1 (SPI-1)-encoded TTSS are required for the intimate association of these bacteria with mammalian cells. S. Typhimurium mutant strains lacking any of the translocases were defective for intimate attachment. Immunofluorescence microscopy showed that SipD is present on the bacterial surface prior to bacterial contact with host cells. In contrast, SipB and SipC were detected on the bacterial surface only subsequent to bacterial contact with the target cell. We conclude that the coordinated deployment and interaction between the protein translocases mediate the SPI-1 TTSS-dependent intimate association of S. Typhimurium with host cells.

  7. Spi-1/PU.1 transgenic mice develop multistep erythroleukemias.

    PubMed Central

    Moreau-Gachelin, F; Wendling, F; Molina, T; Denis, N; Titeux, M; Grimber, G; Briand, P; Vainchenker, W; Tavitian, A

    1996-01-01

    Insertional mutagenesis of the spi-1 gene is associated with the emergence of malignant proerythroblasts during Friend virus-induced acute erythroleukemia. To determine the role of spi-1/PU.1 in the genesis of leukemia, we generated spi-1 transgenic mice. In one founder line the transgene was overexpressed as an unexpected-size transcript in various mouse tissues. Homozygous transgenic animals gave rise to live-born offspring, but 50% of the animals developed a multistep erythroleukemia within 1.5 to 6 months of birth whereas the remainder survived without evidence of disease. At the onset of the disease, mice became severely anemic. Their hematopoietic tissues were massively invaded with nontumorigenic proerythroblasts that express a high level of Spi-1 protein. These transgenic proerythroblasts are partially blocked in differentiation and strictly dependent on erythropoietin for their proliferation both in vivo and in vitro. A complete but transient regression of the disease was observed after erythrocyte transfusion, suggesting that the constitutive expression of spi-1 is related to the block of the differentiation of erythroid precursors. At relapse, erythropoietin-independent malignant proerythroblasts arose. Growth factor autonomy could be partially explained by the autocrine secretion of erythropoietin; however, other genetic events appear to be necessary to confer the full malignant phenotype. These results reveal that overexpression of spi-1 is essential for malignant erythropoiesis and does not alter other hematopoietic lineages. PMID:8628313

  8. Salmonella Typhimurium induces SPI-1 and SPI-2 regulated and strain dependent downregulation of MHC II expression on porcine alveolar macrophages.

    PubMed

    Van Parys, Alexander; Boyen, Filip; Verbrugghe, Elin; Leyman, Bregje; Bram, Flahou; Haesebrouck, Freddy; Pasmans, Frank

    2012-06-13

    Foodborne salmonellosis is one of the most important bacterial zoonotic diseases worldwide. Salmonella Typhimurium is the serovar most frequently isolated from persistently infected slaughter pigs in Europe. Circumvention of the host's immune system by Salmonella might contribute to persistent infection of pigs. In the present study, we found that Salmonella Typhimurium strain 112910a specifically downregulated MHC II, but not MHC I, expression on porcine alveolar macrophages in a Salmonella pathogenicity island (SPI)-1 and SPI-2 dependent way. Salmonella induced downregulation of MHC II expression and intracellular proliferation of Salmonella in macrophages were significantly impaired after opsonization with Salmonella specific antibodies prior to inoculation. Furthermore, the capacity to downregulate MHC II expression on macrophages differed significantly among Salmonella strains, independently of strain specific differences in invasion capacity, Salmonella induced cytotoxicity and altered macrophage activation status. The fact that strain specific differences in MHC II downregulation did not correlate with the extent of in vitro SPI-1 or SPI-2 gene expression indicates that other factors are involved in MHC II downregulation as well. Since Salmonella strain dependent interference with the pig's immune response through downregulation of MHC II expression might indicate that certain Salmonella strains are more likely to escape serological detection, our findings are of major interest for Salmonella monitoring programs primarily based on serology.

  9. Poultry body temperature contributes to invasion control through reduced expression of Salmonella pathogenicity island 1 genes in Salmonella enterica serovars Typhimurium and Enteritidis.

    PubMed

    Troxell, Bryan; Petri, Nicholas; Daron, Caitlyn; Pereira, Rafaela; Mendoza, Mary; Hassan, Hosni M; Koci, Matthew D

    2015-12-01

    Salmonella enterica serovars Typhimurium (S. Typhimurium) and Enteritidis (S. Enteritidis) are foodborne pathogens, and outbreaks are often associated with poultry products. Chickens are typically asymptomatic when colonized by these serovars; however, the factors contributing to this observation are uncharacterized. Whereas symptomatic mammals have a body temperature between 37°C and 39°C, chickens have a body temperature of 41°C to 42°C. Here, in vivo experiments using chicks demonstrated that numbers of viable S. Typhimurium or S. Enteritidis bacteria within the liver and spleen organ sites were ≥4 orders of magnitude lower than those within the ceca. When similar doses of S. Typhimurium or S. Enteritidis were given to C3H/HeN mice, the ratio of the intestinal concentration to the liver/spleen concentration was 1:1. In the avian host, this suggested poor survival within these tissues or a reduced capacity to traverse the host epithelial layer and reach liver/spleen sites or both. Salmonella pathogenicity island 1 (SPI-1) promotes localization to liver/spleen tissues through invasion of the epithelial cell layer. Following in vitro growth at 42°C, SPI-1 genes sipC, invF, and hilA and the SPI-1 rtsA activator were downregulated compared to expression at 37°C. Overexpression of the hilA activators fur, fliZ, and hilD was capable of inducing hilA-lacZ at 37°C but not at 42°C despite the presence of similar levels of protein at the two temperatures. In contrast, overexpression of either hilC or rtsA was capable of inducing hilA and sipC at 42°C. These data indicate that physiological parameters of the poultry host, such as body temperature, have a role in modulating expression of virulence. PMID:26386070

  10. Poultry Body Temperature Contributes to Invasion Control through Reduced Expression of Salmonella Pathogenicity Island 1 Genes in Salmonella enterica Serovars Typhimurium and Enteritidis

    PubMed Central

    Petri, Nicholas; Daron, Caitlyn; Pereira, Rafaela; Mendoza, Mary; Hassan, Hosni M.; Koci, Matthew D.

    2015-01-01

    Salmonella enterica serovars Typhimurium (S. Typhimurium) and Enteritidis (S. Enteritidis) are foodborne pathogens, and outbreaks are often associated with poultry products. Chickens are typically asymptomatic when colonized by these serovars; however, the factors contributing to this observation are uncharacterized. Whereas symptomatic mammals have a body temperature between 37°C and 39°C, chickens have a body temperature of 41°C to 42°C. Here, in vivo experiments using chicks demonstrated that numbers of viable S. Typhimurium or S. Enteritidis bacteria within the liver and spleen organ sites were ≥4 orders of magnitude lower than those within the ceca. When similar doses of S. Typhimurium or S. Enteritidis were given to C3H/HeN mice, the ratio of the intestinal concentration to the liver/spleen concentration was 1:1. In the avian host, this suggested poor survival within these tissues or a reduced capacity to traverse the host epithelial layer and reach liver/spleen sites or both. Salmonella pathogenicity island 1 (SPI-1) promotes localization to liver/spleen tissues through invasion of the epithelial cell layer. Following in vitro growth at 42°C, SPI-1 genes sipC, invF, and hilA and the SPI-1 rtsA activator were downregulated compared to expression at 37°C. Overexpression of the hilA activators fur, fliZ, and hilD was capable of inducing hilA-lacZ at 37°C but not at 42°C despite the presence of similar levels of protein at the two temperatures. In contrast, overexpression of either hilC or rtsA was capable of inducing hilA and sipC at 42°C. These data indicate that physiological parameters of the poultry host, such as body temperature, have a role in modulating expression of virulence. PMID:26386070

  11. Poultry body temperature contributes to invasion control through reduced expression of Salmonella pathogenicity island 1 genes in Salmonella enterica serovars Typhimurium and Enteritidis.

    PubMed

    Troxell, Bryan; Petri, Nicholas; Daron, Caitlyn; Pereira, Rafaela; Mendoza, Mary; Hassan, Hosni M; Koci, Matthew D

    2015-12-01

    Salmonella enterica serovars Typhimurium (S. Typhimurium) and Enteritidis (S. Enteritidis) are foodborne pathogens, and outbreaks are often associated with poultry products. Chickens are typically asymptomatic when colonized by these serovars; however, the factors contributing to this observation are uncharacterized. Whereas symptomatic mammals have a body temperature between 37°C and 39°C, chickens have a body temperature of 41°C to 42°C. Here, in vivo experiments using chicks demonstrated that numbers of viable S. Typhimurium or S. Enteritidis bacteria within the liver and spleen organ sites were ≥4 orders of magnitude lower than those within the ceca. When similar doses of S. Typhimurium or S. Enteritidis were given to C3H/HeN mice, the ratio of the intestinal concentration to the liver/spleen concentration was 1:1. In the avian host, this suggested poor survival within these tissues or a reduced capacity to traverse the host epithelial layer and reach liver/spleen sites or both. Salmonella pathogenicity island 1 (SPI-1) promotes localization to liver/spleen tissues through invasion of the epithelial cell layer. Following in vitro growth at 42°C, SPI-1 genes sipC, invF, and hilA and the SPI-1 rtsA activator were downregulated compared to expression at 37°C. Overexpression of the hilA activators fur, fliZ, and hilD was capable of inducing hilA-lacZ at 37°C but not at 42°C despite the presence of similar levels of protein at the two temperatures. In contrast, overexpression of either hilC or rtsA was capable of inducing hilA and sipC at 42°C. These data indicate that physiological parameters of the poultry host, such as body temperature, have a role in modulating expression of virulence.

  12. Immunization of chickens with Salmonella enterica subspecies enterica serovar Enteritidis pathogenicity island-2 proteins.

    PubMed

    Wisner, Amanda L S; Desin, Taseen S; Lam, Po-King S; Berberov, Emil; Mickael, Claudia S; Townsend, Hugh G; Potter, Andrew A; Köster, Wolfgang

    2011-12-15

    Several structural components of the type III secretion systems (T3SS) encoded by Salmonella pathogenicity island (SPI)-1 and SPI-2 are exposed to the host's immune system prior to/during the infection/invasion process, making them potential vaccine candidates. In this study we evaluated whether chickens vaccinated with SPI-2 T3SS components could mount a significant humoral immune response (as measured by serum IgG titres) and whether these antibodies could be transferred to progeny (as measured by egg yolk IgG titres), and whether vaccinates and progeny of vaccinates could be protected against challenge with SE. The results of our studies show that vaccinated chickens do produce high levels of SPI-2 T3SS specific serum IgG that they are able to transfer to their progeny. It was demonstrated that vaccinates and progeny of vaccinates had lower overall countable recovered Salmonella enterica subspecies enterica serovar Enteritidis (SE) per bird in most situations.

  13. Identifying pathogenicity islands in bacterial pathogenomics using computational approaches.

    PubMed

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

    2014-01-13

    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.

  14. Identifying Pathogenicity Islands in Bacterial Pathogenomics Using Computational Approaches

    PubMed Central

    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). 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. PMID:25437607

  15. Pathogenicity islands and phage conversion: evolutionary aspects of bacterial pathogenesis.

    PubMed

    Dobrindt, U; Reidl, J

    2000-10-01

    Horizontal gene transfer plays a key role in the generation of novel bacterial pathogens. Besides plasmids and bacteriophages, large genomic regions termed pathogenicity islands (PAIs) can be transferred horizontally. All three mechanisms for DNA exchange or transfer may be important for the evolution of bacterial pathogens.

  16. Intestinal Long-Chain Fatty Acids Act as a Direct Signal To Modulate Expression of the Salmonella Pathogenicity Island 1 Type III Secretion System

    PubMed Central

    Ellermeier, Jeremy R.; Cott Chubiz, Jessica E.

    2016-01-01

    ABSTRACT Salmonella enterica serovar Typhimurium uses the Salmonella pathogenicity island 1 (SPI1) type III secretion system (T3SS) to induce inflammatory diarrhea and bacterial uptake into intestinal epithelial cells. The expression of hilA, encoding the transcriptional activator of the T3SS structural genes, is directly controlled by three AraC-like regulators, HilD, HilC, and RtsA, each of which can activate hilD, hilC, rtsA, and hilA genes, forming a complex feed-forward regulatory loop. Expression of the SPI1 genes is tightly controlled by numerous regulatory inputs to ensure proper timing in production of the T3SS apparatus. Loss of FadD, an acyl coenzyme A (acyl-CoA) synthetase required for degradation of long-chain fatty acids (LCFAs), was known to decrease hilA expression. We show that free external LCFAs repress expression of hilA independently of FadD and the LCFA degradation pathway. Genetic and biochemical evidence suggests that LCFAs act directly to block primarily HilD activity. Further analyses show that in the absence of FadD, hilA expression is downregulated due to endogenous production of free LCFAs, which are excreted into the culture medium via TolC and then transported back into the bacterial cell via FadL. A fadL mutant is more virulent than the wild-type strain in mouse oral competition assays independently of LCFA degradation, showing that, in the host, dietary LCFAs serve as a signal for proper regulation of SPI1 expression, rather than an energy source. PMID:26884427

  17. Spy1 participates in the proliferation and apoptosis of epithelial ovarian cancer.

    PubMed

    Lu, Shumin; Liu, Rong; Su, Min; Wei, Yingze; Yang, Shuyun; He, Song; Wang, Xia; Qiang, Fulin; Chen, Chen; Zhao, Shuyang; Zhang, Weiwei; Xu, Pan; Mao, Guoxin

    2016-02-01

    This study focused on determining the role of Spy1 in human epithelial ovarian cancer (EOC). Speedy is a novel cell cycle protein capable of promoting cell proliferation. In this study, western blot and immunohistochemistrical analyses were performed to detect the expression of Spy1 in ovarian cancer. Spy1 protein levels increased with ovarian cancer grade, and Kaplan-Meier curve showed that overexpression of Spy1 was significantly correlated with reduced patient survival. In vitro, Spy1 depletion in ovarian cell lines led to reduced proliferation according to CCK8 and plate colony assays. The expression of Spy1 was positively related to pThr187-p27. Flow cytometry revealed that the reduced expression of Spy1 induced the apoptosis of the EOC cells. In summary, our findings suggested that Spy1 may be a novel independent prognostic predictor of survival for ovarian patients.

  18. Implication of quorum sensing in Salmonella enterica serovar typhimurium virulence: the luxS gene is necessary for expression of genes in pathogenicity island 1.

    PubMed

    Choi, Jeongjoon; Shin, Dongwoo; Ryu, Sangryeol

    2007-10-01

    Despite the fact that the regulatory system sensing density of cell population and its signaling molecule have been identified in Salmonella enterica, the biological significance of this phenomenon termed as quorum sensing remains unknown. In this report, we provide evidence that the luxS gene is necessary for Salmonella virulence phenotypes. Transcription assays showed that the cell-density-dependent induction of the invF gene was abolished in a Salmonella strain with the luxS gene deleted. The effect of the luxS deletion was also investigated in other InvF-regulated genes expressed from Salmonella pathogenicity island 1 (SPI-1). The decreased expression of SPI-1 genes in the strain with luxS deleted could be restored by either the addition of a synthetic signal molecule or the introduction of a plasmid copy of the luxS gene. Thus, the reduced expression of invF and its regulated genes in Salmonella cells lacking quorum sensing resulted in the attenuation of virulence phenotypes both in vitro and in vivo.

  19. Prediction of genomic islands in seven human pathogens using the Z-Island method.

    PubMed

    Wei, W; Guo, F-B

    2011-10-05

    We adopted the method of Zhang and Zhang (the Z-Island method) to identify genomic islands in seven human pathogens, analyzing their chromosomal DNA sequences. The Z-Island method is a theoretical method for predicting genomic islands in bacterial genomes; it consists of determination of the cumulative GC profile and computation of codon usage bias. Thirty-one genomic islands were found in seven pathogens using this method. Further analysis demonstrated that most have the known conserved features; this increases the probability that they are real genomic islands. Eleven genomic islands were found to code for products involved in causing disease (virulence factors) or in resistance to antibiotics (resistance factors). This finding could be useful for research on the pathogenicity of these bacteria and helpful in the treatment of the diseases that they cause. In a comparison of the distribution of mobility elements in genomic islands predicted by different methods, the Z-Island method gave lower false-positive rates. The Z-Island method was found to detect more known genomic islands than the two methods that we compared it with, SIGI-HMM and IslandPick. Furthermore, it maintained a better balance between specificity and sensitivity. The only inconvenience is that the steps for finding genomic islands by the Z-Island method are semi-automatic.

  20. Spi-1/PU.1 activates transcription through clustered DNA occupancy in erythroleukemia.

    PubMed

    Ridinger-Saison, Maya; Boeva, Valentina; Rimmelé, Pauline; Kulakovskiy, Ivan; Gallais, Isabelle; Levavasseur, Benjamin; Paccard, Caroline; Legoix-Né, Patricia; Morlé, François; Nicolas, Alain; Hupé, Philippe; Barillot, Emmanuel; Moreau-Gachelin, Françoise; Guillouf, Christel

    2012-10-01

    Acute leukemias are characterized by deregulation of transcriptional networks that control the lineage specificity of gene expression. The aberrant overexpression of the Spi-1/PU.1 transcription factor leads to erythroleukemia. To determine how Spi-1 mechanistically influences the transcriptional program, we combined a ChIP-seq analysis with transcriptional profiling in cells from an erythroleukemic mouse model. We show that Spi-1 displays a selective DNA-binding that does not often cause transcriptional modulation. We report that Spi-1 controls transcriptional activation and repression partially through distinct Spi-1 recruitment to chromatin. We revealed several parameters impacting on Spi-1-mediated transcriptional activation. Gene activation is facilitated by Spi-1 occupancy close to transcriptional starting site of genes devoid of CGIs. Moreover, in those regions Spi-1 acts by binding to multiple motifs tightly clustered and with similar orientation. Finally, in contrast to the myeloid and lymphoid B cells in which Spi-1 exerts a physiological activity, in the erythroleukemic cells, lineage-specific cooperating factors do not play a prevalent role in Spi-1-mediated transcriptional activation. Thus, our work describes a new mechanism of gene activation through clustered site occupancy of Spi-1 particularly relevant in regard to the strong expression of Spi-1 in the erythroleukemic cells.

  1. Spi-1/PU.1 oncoprotein affects splicing decisions in a promoter binding-dependent manner.

    PubMed

    Guillouf, Christel; Gallais, Isabelle; Moreau-Gachelin, Françoise

    2006-07-14

    The expression of the Spi-1/PU.1 transcription factor is tightly regulated as a function of the hematopoietic lineage. It is required for myeloid and B lymphoid differentiation. When overexpressed in mice, Spi-1 is associated with the emergence of transformed proerythroblasts unable to differentiate. In the course of a project undertaken to characterize the oncogenic function of Spi-1, we found that Spi-1 interacts with proteins of the spliceosome in Spi-1-transformed proerythroblasts and participates in alternative splice site selection. Because Spi-1 is a transcription factor, it could be hypothesized that these two functions are coordinated. Here, we have developed a system allowing the characterization of transcription and splicing from a single target. It is shown that Spi-1 is able to regulate alternative splicing of a pre-mRNA for a gene whose transcription it regulates. Using a combination of Spi-1 mutants and Spi-1-dependent promoters, we demonstrate that Spi-1 must bind and transactivate a given promoter to favor the use of the proximal 5' alternative site. This establishes that Spi-1 affects splicing decisions in a promoter binding-dependent manner. These results provide new insight into how Spi-1 may act in the blockage of differentiation by demonstrating that it can deregulate gene expression and also modify the nature of the products generated from target genes.

  2. Mobility of the Yersinia High-Pathogenicity Island (HPI): transfer mechanisms of pathogenicity islands (PAIS) revisited (a review).

    PubMed

    Benedek, Orsolya; Schubert, S

    2007-06-01

    Horizontal gene transfer (HGT) plays a key role in the evolution of bacterial pathogens. The exchange of genetic material supplies prokaryotes with several fitness traits enhancing their adaptive response to environmental changes. Pathogenicity islands (PAIs) represent an important and in most cases already immobilized subset of the different vehicles for HGT. Encoding several virulence factors PAls represent a major contribution to bacterial pathogenicity. Nonetheless, the transfer mechanisms of PAIs still remain elusive. We summarise the currently available data regarding the major ways of genetic mobilisation with a focus on the transfer of the Yersinia High-Pathogenicity Island (HPI).

  3. Crystallization of a Nonclassical Kazal-type Carcinoscorpius Rotundicauda Serine Protease Inhibitor, CrSPI-1, Complexed with Subtilisin

    SciTech Connect

    Tulsidas, S.; Thangamani, S; Ho, B; Sivaraman, J; Ding, J

    2009-01-01

    Serine proteases play a major role in host-pathogen interactions. The innate immune system is known to respond to invading pathogens in a nonspecific manner. The serine protease cascade is an essential component of the innate immune system of the horseshoe crab. The serine protease inhibitor CrSPI isoform 1 (CrSPI-1), a unique nonclassical Kazal-type inhibitor of molecular weight 9.3 kDa, was identified from the hepatopancreas of the horseshoe crab Carcinoscorpius rotundicauda. It potently inhibits subtilisin and constitutes a powerful innate immune defence against invading microbes. Here, the cloning, expression, purification and cocrystallization of CrSPI-1 with subtilisin are reported. The crystals diffracted to 2.6 {angstrom}resolution and belonged to space group P2{sub 1}, with unit-cell parameters a = 73.8, b = 65.0, c = 111.9 {angstrom}, {beta} = 95.4. The Matthews coefficient (VM = 2.64 {angstrom}3 Da-1, corresponding to 53% solvent content) and analysis of the preliminary structure solution indicated the presence of one heterotrimer (1:2 ratio of CrSPI-1:subtilisin) and one free subtilisin molecule in the asymmetric unit.

  4. Molecular ruler determines needle length for the Salmonella Spi-1 injectisome.

    PubMed

    Wee, Daniel H; Hughes, Kelly T

    2015-03-31

    The type-III secretion (T3S) systems of bacteria are part of self-assembling nanomachines: the bacterial flagellum that enables cells to propel themselves through liquid and across hydrated surfaces, and the injectisome that delivers pathogenic effector proteins into eukaryotic host cells. Although the flagellum and injectisome serve different purposes, they are evolutionarily related and share many structural similarities. Core features to these T3S systems are intrinsic length control mechanisms for external cellular projections: the hook of the flagellum and the injectisome needle. We present evidence that the Spi-1 injectisome, like the Salmonella flagellar hook, uses a secreted molecular ruler, InvJ, to determine needle length. This result supports a universal length control mechanism using molecular rulers for T3S systems. PMID:25775540

  5. Molecular ruler determines needle length for the Salmonella Spi-1 injectisome.

    PubMed

    Wee, Daniel H; Hughes, Kelly T

    2015-03-31

    The type-III secretion (T3S) systems of bacteria are part of self-assembling nanomachines: the bacterial flagellum that enables cells to propel themselves through liquid and across hydrated surfaces, and the injectisome that delivers pathogenic effector proteins into eukaryotic host cells. Although the flagellum and injectisome serve different purposes, they are evolutionarily related and share many structural similarities. Core features to these T3S systems are intrinsic length control mechanisms for external cellular projections: the hook of the flagellum and the injectisome needle. We present evidence that the Spi-1 injectisome, like the Salmonella flagellar hook, uses a secreted molecular ruler, InvJ, to determine needle length. This result supports a universal length control mechanism using molecular rulers for T3S systems.

  6. Pathogenicity islands: a molecular toolbox for bacterial virulence.

    PubMed

    Gal-Mor, Ohad; Finlay, B Brett

    2006-11-01

    Pathogenicity islands (PAIs) are distinct genetic elements on the chromosomes of a large number of bacterial pathogens. PAIs encode various virulence factors and are normally absent from non-pathogenic strains of the same or closely related species. PAIs are considered to be a subclass of genomic islands that are acquired by horizontal gene transfer via transduction, conjugation and transformation, and provide 'quantum leaps' in microbial evolution. Data based on numerous sequenced bacterial genomes demonstrate that PAIs are present in a wide range of both gram-positive and gram-negative bacterial pathogens of humans, animals and plants. Recent research focused on PAIs has not only led to the identification of many novel virulence factors used by these species during infection of their respective hosts, but also dramatically changed our way of thinking about the evolution of bacterial virulence.

  7. The deubiquitinase activity of the Salmonella pathogenicity island 2 effector, SseL, prevents accumulation of cellular lipid droplets.

    PubMed

    Arena, Ellen T; Auweter, Sigrid D; Antunes, L Caetano M; Vogl, A Wayne; Han, Jun; Guttman, Julian A; Croxen, Matthew A; Menendez, Alfredo; Covey, Scott D; Borchers, Christoph H; Finlay, B Brett

    2011-11-01

    To cause disease, Salmonella enterica serovar Typhimurium requires two type III secretion systems that are encoded by Salmonella pathogenicity islands 1 and 2 (SPI-1 and -2). These secretion systems serve to deliver specialized proteins (effectors) into the host cell cytosol. While the importance of these effectors to promote colonization and replication within the host has been established, the specific roles of individual secreted effectors in the disease process are not well understood. In this study, we used an in vivo gallbladder epithelial cell infection model to study the function of the SPI-2-encoded type III effector, SseL. The deletion of the sseL gene resulted in bacterial filamentation and elongation and the unusual localization of Salmonella within infected epithelial cells. Infection with the ΔsseL strain also caused dramatic changes in host cell lipid metabolism and led to the massive accumulation of lipid droplets in infected cells. This phenotype was directly attributable to the deubiquitinase activity of SseL, as a Salmonella strain carrying a single point mutation in the catalytic cysteine also resulted in extensive lipid droplet accumulation. The excessive buildup of lipids due to the absence of a functional sseL gene also was observed in murine livers during S. Typhimurium infection. These results suggest that SseL alters host lipid metabolism in infected epithelial cells by modifying the ubiquitination patterns of cellular targets.

  8. Functional analysis of ssaJ and the ssaK/U operon, 13 genes encoding components of the type III secretion apparatus of Salmonella Pathogenicity Island 2.

    PubMed

    Hensel, M; Shea, J E; Raupach, B; Monack, D; Falkow, S; Gleeson, C; Kubo, T; Holden, D W

    1997-04-01

    We have investigated the structure and transcriptional organization of 13 genes of Salmonella Pathogenicity Island 2 (SPI2) that encode components of the second type III secretion apparatus of Salmonella typhimurium. ssaK, L, M, V, N, O, P, Q, R, S, T, U constitute one operon of 10 kb. ssaJ lles upstream of ssaK and is the terminal gene of another operon. The deduced products of ssaJ, ssaK, ssaV, ssaN, ssaO, ssaQ, ssaR, ssaS, ssaT, and ssaU show greatest similarity to the Yersinia spp. genes yscJ, yscL, lcrD, yscN, yscO, yscQ, yscR, yscS, yscT, and yscU, respectively. The products of the ssaL, ssaM and ssaP genes do not have significant similarity to products of other type III secretion systems, and might be important for the specific function of the SPI2 type III secretion system. Bacterial strains carrying different ssa mutations display minor alterations in terms of serum sensitivity when compared with the wild-type strain, but none are defective in replication within macrophage-like RAW 264.7 cells. However, some of the ssa mutant strains invade HEp2 cells less efficiently and are less cytotoxic to RAW 264.7 macrophages than the wild-type strain. We show that the invasion defect is correlated with a lack of SipC in culture supernatants of these mutant strains. SipC is a product of the SPI1 type III secretion system of S. typhimurium, and is important for epithelial cell invasion. Therefore, mutations in SPI2 can affect the SPI1 secretion system, which raises the possibility of an interaction between the two type III secretion systems.

  9. Spi-1/PU.1 participates in erythroleukemogenesis by inhibiting apoptosis in cooperation with Epo signaling and by blocking erythroid differentiation.

    PubMed

    Rimmelé, Pauline; Kosmider, Olivier; Mayeux, Patrick; Moreau-Gachelin, Françoise; Guillouf, Christel

    2007-04-01

    Overexpression of the transcription factor Spi-1/PU.1 in mice leads to acute erythroleukemia characterized by a differentiation block at the proerythroblastic stage. In this study, we made use of a new cellular system allowing us to reach graded expression of Spi-1 in preleukemic cells to dissect mechanisms of Spi-1/ PU-1 in erythroleukemogenesis. This system is based on conditional production of 1 or 2 spi-1-interfering RNAs stably inserted into spi-1 transgenic proerythroblasts. We show that Spi-1 knock-down was sufficient to reinstate the erythroid differentiation program. This differentiation process was associated with an exit from the cell cycle. Evidence is provided that in the presence of erythropoietin (Epo), Spi-1 displays an antiapoptotic role that is independent of its function in blocking erythroid differentiation. Apoptosis inhibited by Spi-1 did not involve activation of the Fas/FasL signaling pathway nor a failure to activate Epo receptor (EpoR). Furthermore, we found that reducing the Spi-1 level yields to ERK dephosphorylation and increased phosphorylation of AKT and STAT5, suggesting that Spi-1 may affect major signaling pathways downstream of the EpoR in erythroid cells. These findings reveal 2 distinct roles for Spi-1 during erythroleukemogenesis: Spi-1 blocks the erythroid differentiation program and acts to impair apoptotic death in cooperation with an Epo signaling.

  10. Towards pathogenomics: a web-based resource for pathogenicity islands.

    PubMed

    Yoon, Sung Ho; Park, Young-Kyu; Lee, Soohyun; Choi, Doil; Oh, Tae Kwang; Hur, Cheol-Goo; Kim, Jihyun F

    2007-01-01

    Pathogenicity islands (PAIs) are genetic elements whose products are essential to the process of disease development. They have been horizontally (laterally) transferred from other microbes and are important in evolution of pathogenesis. In this study, a comprehensive database and search engines specialized for PAIs were established. The pathogenicity island database (PAIDB) is a comprehensive relational database of all the reported PAIs and potential PAI regions which were predicted by a method that combines feature-based analysis and similarity-based analysis. Also, using the PAI Finder search application, a multi-sequence query can be analyzed onsite for the presence of potential PAIs. As of April 2006, PAIDB contains 112 types of PAIs and 889 GenBank accessions containing either partial or all PAI loci previously reported in the literature, which are present in 497 strains of pathogenic bacteria. The database also offers 310 candidate PAIs predicted from 118 sequenced prokaryotic genomes. With the increasing number of prokaryotic genomes without functional inference and sequenced genetic regions of suspected involvement in diseases, this web-based, user-friendly resource has the potential to be of significant use in pathogenomics. PAIDB is freely accessible at http://www.gem.re.kr/paidb.

  11. Epigenetic silencing of Bim transcription by Spi-1/PU.1 promotes apoptosis resistance in leukaemia.

    PubMed

    Ridinger-Saison, M; Evanno, E; Gallais, I; Rimmelé, P; Selimoglu-Buet, D; Sapharikas, E; Moreau-Gachelin, F; Guillouf, C

    2013-09-01

    Deregulation of transcriptional networks contributes to haematopoietic malignancies. The transcription factor Spi-1/PU.1 is a master regulator of haematopoiesis and its alteration leads to leukaemia. Spi-1 overexpression inhibits differentiation and promotes resistance to apoptosis in erythroleukaemia. Here, we show that Spi-1 inhibits mitochondrial apoptosis in vitro and in vivo through the transcriptional repression of Bim, a proapoptotic factor. BIM interacts with MCL-1 that behaves as a major player in the survival of the preleukaemic cells. The repression of BIM expression reduces the amount of BIM-MCL-1 complexes, thus increasing the fraction of potentially active antiapoptotic MCL-1. We then demonstrate that Spi-1 represses Bim transcription by binding to the Bim promoter and by promoting the trimethylation of histone 3 on lysine 27 (H3K27me3, a repressive histone mark) on the Bim promoter. The PRC2 repressive complex of Polycomb is directly responsible for the deposit of H3K27me3 mark at the Bim promoter. SUZ12 and the histone methyltransferase EZH2, two PRC2 subunits bind to the Bim promoter at the same location than H3K27me3, distinct of the Spi-1 DNA binding site. As Spi-1 interacts with SUZ12 and EZH2, these results indicate that Spi-1 modulates the activity of PRC2 without directly recruiting the complex to the site of its activity on the chromatin. Our results identify a new mechanism whereby Spi-1 represses transcription and provide mechanistic insights on the antiapoptotic function of a transcription factor mediated by the epigenetic control of gene expression.

  12. Genetic islands in pome fruit pathogenic and non-pathogenic Erwinia species and related plasmids

    PubMed Central

    Llop, Pablo

    2015-01-01

    New pathogenic bacteria belonging to the genus Erwinia associated with pome fruit trees (Erwinia, E. piriflorinigrans, E. uzenensis) have been increasingly described in the last years, and comparative analyses have found that all these species share several genetic characteristics. Studies at different level (whole genome comparison, virulence genes, plasmid content, etc.) show a high intraspecies homogeneity (i.e., among E. amylovora strains) and also abundant similarities appear between the different Erwinia species: presence of plasmids of similar size in the pathogenic species; high similarity in several genes associated with exopolysaccharide production and hence, with virulence, as well as in some other genes, in the chromosomes. Many genetic similarities have been observed also among some of the plasmids (and genomes) from the pathogenic species and E. tasmaniensis or E. billingiae, two epiphytic species on the same hosts. The amount of genetic material shared in this genus varies from individual genes to clusters, genomic islands and genetic material that even may constitute a whole plasmid. Recent research on evolution of erwinias point out the horizontal transfer acquisition of some genomic islands that were subsequently lost in some species and several pathogenic traits that are still present. How this common material has been obtained and is efficiently maintained in different species belonging to the same genus sharing a common ecological niche provides an idea of the origin and evolution of the pathogenic Erwinia and the interaction with non-pathogenic species present in the same niche, and the role of the genes that are conserved in all of them. PMID:26379649

  13. Genomic Islands in the Pathogenic Filamentous Fungus Aspergillus fumigatus

    PubMed Central

    Fedorova, Natalie D.; Khaldi, Nora; Joardar, Vinita S.; Maiti, Rama; Amedeo, Paolo; Anderson, Michael J.; Crabtree, Jonathan; Silva, Joana C.; Badger, Jonathan H.; Albarraq, Ahmed; Angiuoli, Sam; Bussey, Howard; Bowyer, Paul; Cotty, Peter J.; Dyer, Paul S.; Egan, Amy; Galens, Kevin; Fraser-Liggett, Claire M.; Haas, Brian J.; Inman, Jason M.; Kent, Richard; Lemieux, Sebastien; Malavazi, Iran; Orvis, Joshua; Roemer, Terry; Ronning, Catherine M.; Sundaram, Jaideep P.; Sutton, Granger; Turner, Geoff; Venter, J. Craig; White, Owen R.; Whitty, Brett R.; Youngman, Phil; Wolfe, Kenneth H.; Goldman, Gustavo H.; Wortman, Jennifer R.; Jiang, Bo; Denning, David W.; Nierman, William C.

    2008-01-01

    We present the genome sequences of a new clinical isolate of the important human pathogen, Aspergillus fumigatus, A1163, and two closely related but rarely pathogenic species, Neosartorya fischeri NRRL181 and Aspergillus clavatus NRRL1. Comparative genomic analysis of A1163 with the recently sequenced A. fumigatus isolate Af293 has identified core, variable and up to 2% unique genes in each genome. While the core genes are 99.8% identical at the nucleotide level, identity for variable genes can be as low 40%. The most divergent loci appear to contain heterokaryon incompatibility (het) genes associated with fungal programmed cell death such as developmental regulator rosA. Cross-species comparison has revealed that 8.5%, 13.5% and 12.6%, respectively, of A. fumigatus, N. fischeri and A. clavatus genes are species-specific. These genes are significantly smaller in size than core genes, contain fewer exons and exhibit a subtelomeric bias. Most of them cluster together in 13 chromosomal islands, which are enriched for pseudogenes, transposons and other repetitive elements. At least 20% of A. fumigatus-specific genes appear to be functional and involved in carbohydrate and chitin catabolism, transport, detoxification, secondary metabolism and other functions that may facilitate the adaptation to heterogeneous environments such as soil or a mammalian host. Contrary to what was suggested previously, their origin cannot be attributed to horizontal gene transfer (HGT), but instead is likely to involve duplication, diversification and differential gene loss (DDL). The role of duplication in the origin of lineage-specific genes is further underlined by the discovery of genomic islands that seem to function as designated “gene dumps” and, perhaps, simultaneously, as “gene factories”. PMID:18404212

  14. tkt1, located on a novel pathogenicity island, is prevalent in avian and human extraintestinal pathogenic Escherichia coli

    PubMed Central

    2012-01-01

    Background Extraintestinal pathogenic Escherichia coli are important pathogens of human and animal hosts. Some human and avian extraintestinal pathogenic E. coli are indistinguishable on the basis of diseases caused, multilocus sequence and phylogenetic typing, carriage of large virulence plasmids and traits known to be associated with extraintestinal pathogenic E. coli virulence. Results The gene tkt1 identified by a previous signature-tagged transposon mutagenesis study, was found on a 16-kb genomic island of avian pathogenic Escherichia coli (APEC) O1, the first pathogenic Escherichia coli strain whose genome has been completely sequenced. tkt1 was present in 39.6% (38/96) of pathogenic Escherichia coli strains, while only 6.25% (3/48) of E. coli from the feces of apparently healthy chickens was positive. Further, tkt1 was predominantly present in extraintestinal pathogenic E. coli belonging to the B2 phylogenetic group, as compared to extraintestinal pathogenic E. coli of other phylogenetic groups. The tkt1-containing genomic island is inserted between the metE and ysgA genes of the E. coli K12 genome. Among different extraintestinal pathogenic E. coli of the B2 phylogenetic group, 61.7% of pathogenic Escherichia coli, 80.6% of human uropathogenic E.coli and 94.1% of human neonatal meningitis-causing E. coli, respectively, harbor a complete copy of this island; whereas, only a few avian fecal E. coli strains contained the complete island. Functional analysis showed that Tkt1 confers very little transketolase activity but is involved in peptide nitrogen metabolism. Conclusion These results suggest tkt1 and its corresponding genomic island are frequently associated with avian and human ExPEC and are involved in bipeptide metabolism. PMID:22471764

  15. Identification of genomic islands in six plant pathogens.

    PubMed

    Chen, Ling-Ling

    2006-06-01

    Genomic islands (GIs) play important roles in microbial evolution, which are acquired by horizontal gene transfer. In this paper, the GIs of six completely sequenced plant pathogens are identified using a windowless method based on Z curve representation of DNA sequences. Consequently, four, eight, four, one, two and four GIs are recognized with the length greater than 20-Kb in plant pathogens Agrobacterium tumefaciens str. C58, Rolstonia solanacearum GMI1000, Xanthomonas axonopodis pv. citri str. 306 (Xac), Xanthomonas campestris pv. campestris str. ATCC33913 (Xcc), Xylella fastidiosa 9a5c and Pseudomonas syringae pv. tomato str. DC3000, respectively. Most of these regions share a set of conserved features of GIs, including an abrupt change in GC content compared with that of the rest of the genome, the existence of integrase genes at the junction, the use of tRNA as the integration sites, the presence of genetic mobility genes, the difference of codon usage, codon preference and amino acid usage, etc. The identification of these GIs will benefit the research for the six important phytopathogens.

  16. Pathogenicity-associated islands in extraintestinal pathogenic Escherichia coli are fitness elements involved in intestinal colonization.

    PubMed

    Diard, Médéric; Garry, Louis; Selva, Marjorie; Mosser, Thomas; Denamur, Erick; Matic, Ivan

    2010-10-01

    The virulence of many human pathogens does not seem to be an evolutionarily selected trait, but an accidental by-product of the selection that operates in another ecological context. We investigated the possibility that virulence of the extraintestinal pathogenic Escherichia coli (ExPEC) strains, which frequently cause disease in the host in which they asymptomatically colonize the intestine, is the consequence of commensalism. Most of the ExPEC virulence factors are clustered on genomic islands called pathogenicity-associated islands (PAIs). We constructed and characterized several mutants of the ExPEC 536 strain with either (i) deletions of each single PAI or (ii) a complete deletion of all seven PAIs. In vitro phenotypic characterization of 536 mutants showed that the seven PAIs were dispensable for growth in the absence of external stress, as well as under a range of biologically relevant stressors, i.e., serum, bile, and oxidative, nitrosative, hyperosmotic, and acidic stress. However, challenge against the wild-type (WT) strain in a murine model shows that the deletion of all seven PAIs drastically reduces the fitness of 536 during persistent intestinal colonization. This defect seems to be linked to the hypermotility observed for mutants devoid of all seven PAIs. In addition, we show that PAIs diminish fitness of their carrier during growth in urine, suggesting that urinary tract infections are unlikely to provide selective pressure for the maintenance of ExPEC PAIs. Our results are in accordance with the coincidental-evolution hypothesis postulating that extraintestinal E. coli virulence is a by-product of commensalism.

  17. Epigenetic Control of SPI1 Gene by CTCF and ISWI ATPase SMARCA5

    PubMed Central

    Dluhosova, Martina; Curik, Nikola; Vargova, Jarmila; Jonasova, Anna; Zikmund, Tomas; Stopka, Tomas

    2014-01-01

    CCCTC-binding factor (CTCF) can both activate as well as inhibit transcription by forming chromatin loops between regulatory regions and promoters. In this regard, Ctcf binding on non-methylated DNA and its interaction with the Cohesin complex results in differential regulation of the H19/Igf2 locus. Similarly, a role for CTCF has been established in normal hematopoietic development; however its involvement in leukemia remains elusive. Here, we show that Ctcf binds to the imprinting control region of H19/Igf2 in AML blasts. We also demonstrate that Smarca5, which also associates with the Cohesin complex, facilitates Ctcf binding to its target sites on DNA. Furthermore, Smarca5 supports Ctcf functionally and is needed for enhancer-blocking effect at ICR. We next asked whether CTCF and SMARCA5 control the expression of key hematopoiesis regulators. In normally differentiating myeloid cells both CTCF and SMARCA5 together with members of the Cohesin complex are recruited to the SPI1 gene, a key hematopoiesis regulator and leukemia suppressor. Due to DNA methylation, CTCF binding to the SPI1 gene is blocked in AML blasts. Upon AZA-mediated DNA demethylation of human AML blasts, CTCF and SMARCA5 are recruited to the −14.4 Enhancer of SPI1 gene and block its expression. Our data provide new insight into complex SPI1 gene regulation now involving additional key epigenetic factors, CTCF and SMARCA5 that control PU.1 expression at the −14.4 Enhancer. PMID:24498324

  18. Convergent evolution of pathogenicity islands in helper cos phage interference.

    PubMed

    Carpena, Nuria; Manning, Keith A; Dokland, Terje; Marina, Alberto; Penadés, José R

    2016-11-01

    Staphylococcus aureus pathogenicity islands (SaPIs) are phage satellites that exploit the life cycle of their helper phages for their own benefit. Most SaPIs are packaged by their helper phages using a headful (pac) packaging mechanism. These SaPIs interfere with pac phage reproduction through a variety of strategies, including the redirection of phage capsid assembly to form small capsids, a process that depends on the expression of the SaPI-encoded cpmA and cpmB genes. Another SaPI subfamily is induced and packaged by cos-type phages, and although these cos SaPIs also block the life cycle of their inducing phages, the basis for this mechanism of interference remains to be deciphered. Here we have identified and characterized one mechanism by which the SaPIs interfere with cos phage reproduction. This mechanism depends on a SaPI-encoded gene, ccm, which encodes a protein involved in the production of small isometric capsids, compared with the prolate helper phage capsids. As the Ccm and CpmAB proteins are completely unrelated in sequence, this strategy represents a fascinating example of convergent evolution. Moreover, this result also indicates that the production of SaPI-sized particles is a widespread strategy of phage interference conserved during SaPI evolution.This article is part of the themed issue 'The new bacteriology'.

  19. Convergent evolution of pathogenicity islands in helper cos phage interference

    PubMed Central

    Manning, Keith A.; Dokland, Terje; Marina, Alberto

    2016-01-01

    Staphylococcus aureus pathogenicity islands (SaPIs) are phage satellites that exploit the life cycle of their helper phages for their own benefit. Most SaPIs are packaged by their helper phages using a headful (pac) packaging mechanism. These SaPIs interfere with pac phage reproduction through a variety of strategies, including the redirection of phage capsid assembly to form small capsids, a process that depends on the expression of the SaPI-encoded cpmA and cpmB genes. Another SaPI subfamily is induced and packaged by cos-type phages, and although these cos SaPIs also block the life cycle of their inducing phages, the basis for this mechanism of interference remains to be deciphered. Here we have identified and characterized one mechanism by which the SaPIs interfere with cos phage reproduction. This mechanism depends on a SaPI-encoded gene, ccm, which encodes a protein involved in the production of small isometric capsids, compared with the prolate helper phage capsids. As the Ccm and CpmAB proteins are completely unrelated in sequence, this strategy represents a fascinating example of convergent evolution. Moreover, this result also indicates that the production of SaPI-sized particles is a widespread strategy of phage interference conserved during SaPI evolution. This article is part of the themed issue ‘The new bacteriology’. PMID:27672154

  20. Convergent evolution of pathogenicity islands in helper cos phage interference.

    PubMed

    Carpena, Nuria; Manning, Keith A; Dokland, Terje; Marina, Alberto; Penadés, José R

    2016-11-01

    Staphylococcus aureus pathogenicity islands (SaPIs) are phage satellites that exploit the life cycle of their helper phages for their own benefit. Most SaPIs are packaged by their helper phages using a headful (pac) packaging mechanism. These SaPIs interfere with pac phage reproduction through a variety of strategies, including the redirection of phage capsid assembly to form small capsids, a process that depends on the expression of the SaPI-encoded cpmA and cpmB genes. Another SaPI subfamily is induced and packaged by cos-type phages, and although these cos SaPIs also block the life cycle of their inducing phages, the basis for this mechanism of interference remains to be deciphered. Here we have identified and characterized one mechanism by which the SaPIs interfere with cos phage reproduction. This mechanism depends on a SaPI-encoded gene, ccm, which encodes a protein involved in the production of small isometric capsids, compared with the prolate helper phage capsids. As the Ccm and CpmAB proteins are completely unrelated in sequence, this strategy represents a fascinating example of convergent evolution. Moreover, this result also indicates that the production of SaPI-sized particles is a widespread strategy of phage interference conserved during SaPI evolution.This article is part of the themed issue 'The new bacteriology'. PMID:27672154

  1. Spi-1/PU.1 oncogene accelerates DNA replication fork elongation and promotes genetic instability in the absence of DNA breakage.

    PubMed

    Rimmelé, Pauline; Komatsu, Jun; Hupé, Philippe; Roulin, Christophe; Barillot, Emmanuel; Dutreix, Marie; Conseiller, Emmanuel; Bensimon, Aaron; Moreau-Gachelin, Françoise; Guillouf, Christel

    2010-09-01

    The multistage process of cancer formation is driven by the progressive acquisition of somatic mutations. Replication stress creates genomic instability in mammals. Using a well-defined multistep leukemia model driven by Spi-1/PU.1 overexpression in the mouse and Spi-1/PU.1-overexpressing human leukemic cells, we investigated the relationship between DNA replication and cancer progression. Here, using DNA molecular combing and flow cytometry methods, we show that Spi-1 increases the speed of replication by acting specifically on elongation rather than enhancing origin firing. This shortens the S-phase duration. Combining data from Spi-1 knockdown in murine cells with Spi-1 overexpression in human cells, we provide evidence that inappropriate Spi-1 expression is directly responsible for the replication alteration observed. Importantly, the acceleration of replication progression coincides with an increase in the frequency of genomic mutations without inducing DNA breakage. Thus, we propose that the hitherto unsuspected role for spi-1 oncogene in promoting replication elongation and genomic mutation promotes blastic progression during leukemic development.

  2. Characterization of the SPI-1 and Rsp type three secretion systems in Pseudomonas fluorescens F113.

    PubMed

    Barret, Matthieu; Egan, Frank; Moynihan, Jennifer; Morrissey, John P; Lesouhaitier, Olivier; O'Gara, Fergal

    2013-06-01

    Pseudomonas fluorescens F113 is a plant growth-promoting rhizobacterium (PGPR) isolated from the sugar beet rhizosphere. The recent annotation of the F113 genome sequence has revealed that this strain encodes a wide array of secretion systems, including two complete type three secretion systems (T3SSs) belonging to the Hrp1 and SPI-1 families. While Hrp1 T3SSs are frequently encoded in other P. fluorescens strains, the presence of a SPI-1 T3SS in a plant-beneficial bacterial strain was unexpected. In this work, the genetic organization and expression of these two T3SS loci have been analysed by a combination of transcriptional reporter fusions and transcriptome analyses. Overexpression of two transcriptional activators has shown a number of genes encoding putative T3 effectors. In addition, the influence of these two T3SSs during the interaction of P. fluorescens F113 with some bacterial predators was also assessed. Our data revealed that the transcriptional activator hilA is induced by amoeba and that the SPI-1 T3SS could potentially be involved in resistance to amoeboid grazing.

  3. Impact of the locus of enterocyte effacement pathogenicity island on the evolution of pathogenic Escherichia coli.

    PubMed

    Jores, Joerg; Rumer, Leonid; Wieler, Lothar H

    2004-09-01

    This review summarizes our current knowledge and models of appearance and dissemination of the locus of enterocyte effacement (LEE) within Escherichia coli phylogenetic lineages. The LEE is a pathogenicity island (PAI) required for attaching and effacing (A/E) lesion formation induced on epithelial cells of humans and animals by enteropathogenic and numerous enterohemorrhagic E. coli strains as well as other related bacteria. The LEE encodes a type III secretion system, an adhesin (intimin) responsible for the intimate attachment of the bacteria to the cell and a number of secreted proteins involved in signal transduction events. It has been shown that the LEE varies in size from 36 to 111 kb, depending on what E. coli lineages carrying that PAI. Three tRNA genes are known as LEE integration sites selC, pheU and pheV, the latter two are identical in sequence. Beneath its functional role, intimin is considered a phylogenetic marker of the LEE. Currently, 14 different intimin types have been described, designated alpha through ksi. Beta intimin-carrying LEEs moved within certain E. coli lineages from the pheU tRNA gene into the pheV tRNA gene. Moreover, as a result of the typing of multiple LEE core regions, the appearance of two different LEE cores indicates an import of the LEE within E. coli at least two times.

  4. Contribution of phage-derived genomic islands to the virulence of facultative bacterial pathogens.

    PubMed

    Busby, Ben; Kristensen, David M; Koonin, Eugene V

    2013-02-01

    Facultative pathogens have extremely dynamic pan-genomes, to a large extent derived from bacteriophages and other mobile elements. We developed a simple approach to identify phage-derived genomic islands and apply it to show that pathogens from diverse bacterial genera are significantly enriched in clustered phage-derived genes compared with related benign strains. These findings show that genome expansion by integration of prophages containing virulence factors is a major route of evolution of facultative bacterial pathogens.

  5. Analyses of the cag pathogenicity island of Helicobacter pylori.

    PubMed

    Akopyants, N S; Clifton, S W; Kersulyte, D; Crabtree, J E; Youree, B E; Reece, C A; Bukanov, N O; Drazek, E S; Roe, B A; Berg, D E

    1998-04-01

    Most strains of Helicobacter pylori from patients with peptic ulcer disease or intestinal-type gastric cancer carry cagA, a gene that encodes an immunodominant protein of unknown function, whereas many of the strains from asymptomatically infected persons lack this gene. Recent studies showed that the cagA gene lies near the right end of a approximately 37kb DNA segment (a pathogenicity island, or PAI) that is unique to cagA+ strains and that the cag PAI was split in half by a transposable element insertion in the reference strain NCTC11638. In complementary experiments reported here, we also found the same cag PAI, and sequenced a 39 kb cosmid clone containing the left 'cagII' half of this PAI. Encoded in cagII were four proteins each with homology to four components of multiprotein complexes of Bordetella pertussis ('Ptl'), Agrobacterium tumefaciens ('Vir'), and conjugative plasmids ('Tra') that help deliver pertussis toxin and T (tumour inducing) and plasmid DNA, respectively, to target eukaryotic or prokaryotic cells, and also homologues of eukaryotic proteins that are involved in cytoskeletal structure. To the left of cagII in this cosmid were genes for homologues of HsIU (heat-shock protein) and Era (essential GTPase); to the right of cagII were homologues of genes for a type I restriction endonuclease and ion transport functions. Deletion of the cag PAI had no effect on synthesis of the vacuolating cytotoxin, but this deletion and several cag insertion mutations blocked induction of synthesis of proinflammatory cytokine IL-8 in gastric epithelial cells. Comparisons among H. pylori strains indicated that cag PAI gene content and arrangement are rather well conserved. We also identified two genome rearrangements with end-points in the cag PAI. One, in reference strain NCTC11638, involved IS605, a recently described transposable element (as also found by others). Another rearrangement, in 3 of 10 strains tested (including type strain NCTC11637), separated the

  6. Chromosomal excision of a new pathogenicity island modulates Salmonella virulence in vivo.

    PubMed

    Tobar, Hugo E; Salazar-Echegarai, Franciso J; Nieto, Pamela A; Palavecino, Christian E; Sebastian, Vatenlina P; Riedel, Claudia A; Kalergis, Alexis M; Bueno, Susan M

    2013-08-01

    Although the excision of unstable pathogenicity islands is a phenomenon that has been described for several virulent bacteria, whether this process directly affects the capacity of these microorganisms to cause disease in their hosts remains unknown. Salmonella enterica serovar Enteritidis (S. Enteritidis) is an enterobacterium that harbors several unstable pathogenicity islands that can excise from the main bacterial chromosome. Here we have evaluated whether excision of one of these pathogenicity islands, denominated as Region of Difference 21 (ROD21), is required for S. Enteritidis to cause disease in the host. By means of genetic targeting of the integrase encoded by the ROD21 we have generated S. Enteritidis strains unable to excise ROD21. The failure to excise ROD21 significantly reduced the capacity to cause a lethal disease and to colonize the spleen and liver of mice, as compared to wild type S. Enteritidis. On the contrary, S. Enteritidis strains overexpressing an excisionase protein increased the frequency of ROD21 excision and showed an improved capacity to cause lethal disease in mice. Accordingly, strains unable to excise ROD21 showed an altered expression of genes located in this pathogenicity island. Our results suggest that the genetic excision of the pathogenicity island ROD21 in S. Enteritidis modulates the capacity of this bacterium to cause disease in mice due to a change in the expression of virulence genes.

  7. Genomic Islands in Pathogenic Filamentous Fungus Aspergillus fumigatus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We present the genome sequences of a new clinical isolate, CEA10, of an important human pathogen, Aspergillus fumigatus, and two closely related, but rarely pathogenic species, Neosartorya fischeri NRRL181 and Aspergillus clavatus NRRL1. Comparative genomic analysis of CEA10 with the recently sequen...

  8. Spi-1 and Fli-1 directly activate common target genes involved in ribosome biogenesis in Friend erythroleukemic cells.

    PubMed

    Juban, Gaëtan; Giraud, Guillaume; Guyot, Boris; Belin, Stéphane; Diaz, Jean-Jacques; Starck, Joëlle; Guillouf, Christel; Moreau-Gachelin, Françoise; Morlé, François

    2009-05-01

    Spi-1 and Fli-1 are ETS transcription factors recurrently deregulated in mouse erythroleukemia induced by Friend viruses. Since they share the same core DNA binding site, we investigated whether they may contribute to erythroleukemia by common mechanisms. Using inducible knockdown, we demonstrated that Fli-1 contributes to proliferation, survival, and differentiation arrest of erythroleukemic cells harboring an activated fli-1 locus. Similarly, we used inducible Fli-1 knockdown and either hexamethylenebisacetamide (HMBA)- or small interfering RNA-mediated Spi-1 knockdown to investigate their respective contributions in erythroleukemic cells harboring an activated spi-1 locus. In these cells, simple or double knockdown of both Spi-1 and Fli-1 additively contributed to induce proliferation arrest and differentiation. Transcriptome profiling revealed that virtually all transcripts affected by both Fli-1 knockdown and HMBA are affected in an additive manner. Among these additively downregulated transcripts, more than 20% encode proteins involved in ribosome biogenesis, and conserved ETS binding sites are present in their gene promoters. Through chromatin immunoprecipitation, we demonstrated the association of Spi-1 and Fli-1 on these promoters in Friend erythroleukemic cells. These data lead us to propose that the oncogenicity of Spi-1, Fli-1, and possibly other ETS transcription factors may involve their ability to stimulate ribosome biogenesis.

  9. The pap Operon of Avian Pathogenic Escherichia coli Strain O1:K1 Is Located on a Novel Pathogenicity Island

    PubMed Central

    Kariyawasam, Subhashinie; Johnson, Timothy J.; Nolan, Lisa K.

    2006-01-01

    We have identified a 56-kb pathogenicity island (PAI) in avian pathogenic Escherichia coli strain O1:K1 (APEC-O1). This PAI, termed PAI IAPEC-O1, is integrated adjacent to the 3′ end of the pheV tRNA gene. It carries putative virulence genes of APEC (pap operon), other E. coli genes (tia and ireA), and a 1.5-kb region unique to APEC-O1. The kps gene cluster required for the biosynthesis of polysialic acid capsule was mapped to a location immediately downstream of this PAI. PMID:16369033

  10. [Plasticity of bacterial genomes: pathogenicity islands and the locus of enterocyte effacement (LEE)].

    PubMed

    Kirsch, Petra; Jores, Jörg; Wieler, Lothar H

    2004-01-01

    Many bacterial virulence attributes, like toxins, adhesins, invasins, iron uptake systems, are encoded within specific regions of the bacterial genome. These in size varying regions are termed pathogenicity islands (PAIs) since they confer pathogenic properties to the respective micro-organism. Per definition PAIs are exclusively found in pathogenic strains and are often inserted near transfer-RNA genes. Nevertheless, non-pathogenic bacteria also possess foreign DNA elements that confer advantageous features, leading to improved fitness. These additional DNA elements as well as PAIs are termed genomic islands and were acquired during bacterial evolution. Significant G+C content deviation in pathogenicity islands with respect to the rest of the genome, the presence of direct repeat sequences at the flanking regions, the presence of integrase gene determinants as other mobility features,the particular insertion site (tRNA gene) as well as the observed genetic instability suggests that pathogenicity islands were acquired by horizontal gene transfer. PAIs are the fascinating proof of the plasticity of bacterial genomes. PAIs were originally described in human pathogenic Escherichia (E.) coli strains. In the meantime PAIs have been found in various pathogenic bacteria of humans, animals and even plants. The Locus of Enterocyte Effacement (LEE) is one particular widely distributed PAI of E coli. In addition, it also confers pathogenicity to the related species Citrobacter (C.) rodentium and Escherichia (E.) alvei. The LEE is an important virulence feature of several animal pathogens. It is an obligate PAI of all animal and human enteropathogenic E. coli (EPEC), and most enterohaemorrhegic E. coli (EHEC) also harbor the LEE. The LEE encodes a type III secretion system, an adhesion (intimin) that mediates the intimate contact between the bacterium and the epithelial cell, as well as various proteins which are secreted via the type III secretion system. The LEE encoded

  11. PAIDB v2.0: exploration and analysis of pathogenicity and resistance islands

    PubMed Central

    Yoon, Sung Ho; Park, Young-Kyu; Kim, Jihyun F.

    2015-01-01

    Pathogenicity is a complex multifactorial process confounded by the concerted activity of genetic regions associated with virulence and/or resistance determinants. Pathogenicity islands (PAIs) and resistance islands (REIs) are key to the evolution of pathogens and appear to play complimentary roles in the process of bacterial infection. While PAIs promote disease development, REIs give a fitness advantage to the host against multiple antimicrobial agents. The Pathogenicity Island Database (PAIDB, http://www.paidb.re.kr) has been the only database dedicated to providing comprehensive information on all reported PAIs and candidate PAIs in prokaryotic genomes. In this study, we present PAIDB v2.0, whose functionality is extended to incorporate REIs. PAIDB v2.0 contains 223 types of PAIs with 1331 accessions, and 88 types of REIs with 108 accessions. With an improved detection scheme, 2673 prokaryotic genomes were analyzed to locate candidate PAIs and REIs. With additional quantitative and qualitative advancements in database content and detection accuracy, PAIDB will continue to facilitate pathogenomic studies of both pathogenic and non-pathogenic organisms. PMID:25336619

  12. PAIDB v2.0: exploration and analysis of pathogenicity and resistance islands.

    PubMed

    Yoon, Sung Ho; Park, Young-Kyu; Kim, Jihyun F

    2015-01-01

    Pathogenicity is a complex multifactorial process confounded by the concerted activity of genetic regions associated with virulence and/or resistance determinants. Pathogenicity islands (PAIs) and resistance islands (REIs) are key to the evolution of pathogens and appear to play complimentary roles in the process of bacterial infection. While PAIs promote disease development, REIs give a fitness advantage to the host against multiple antimicrobial agents. The Pathogenicity Island Database (PAIDB, http://www.paidb.re.kr) has been the only database dedicated to providing comprehensive information on all reported PAIs and candidate PAIs in prokaryotic genomes. In this study, we present PAIDB v2.0, whose functionality is extended to incorporate REIs. PAIDB v2.0 contains 223 types of PAIs with 1331 accessions, and 88 types of REIs with 108 accessions. With an improved detection scheme, 2673 prokaryotic genomes were analyzed to locate candidate PAIs and REIs. With additional quantitative and qualitative advancements in database content and detection accuracy, PAIDB will continue to facilitate pathogenomic studies of both pathogenic and non-pathogenic organisms.

  13. New insights about excisable pathogenicity islands in Salmonella and their contribution to virulence.

    PubMed

    Nieto, Pamela A; Pardo-Roa, Catalina; Salazar-Echegarai, Francisco J; Tobar, Hugo E; Coronado-Arrázola, Irenice; Riedel, Claudia A; Kalergis, Alexis M; Bueno, Susan M

    2016-05-01

    Pathogenicity islands (PAIs) are regions of the chromosome of pathogenic bacteria that harbor virulence genes, which were probably acquired by lateral gene transfer. Several PAIs can excise from the bacterial chromosome by site-specific recombination and in this review have been denominated "excisable PAIs". Here, the characteristic of some of the excisable PAIs from Salmonella enterica and the possible role and impact of the excision process on bacterial virulence is discussed. Understanding the role of PAI excision could provide important insights relative to the emergence, evolution and virulence of pathogenic enterobacteria.

  14. Cooperation of Salmonella pathogenicity islands 1 and 4 is required to breach epithelial barriers.

    PubMed

    Gerlach, Roman G; Cláudio, Nuno; Rohde, Manfred; Jäckel, Daniela; Wagner, Carolin; Hensel, Michael

    2008-11-01

    Invasion is an important microbial virulence strategy to overcome the barrier formed by polarized epithelial cells. Salmonella enterica is a food-borne pathogen that deploys a type III secretion system for the manipulation of the actin cytoskeleton and to trigger internalization into epithelial cells. Here we show that this function is not sufficient to enter polarized cells and report that penetration of epithelia from the luminal side requires both the type III secretion system and novel virulence functions conferred by Salmonella pathogenicity island 4. Salmonella pathogenicity island 4 encodes a type I secretion system for the giant non-fimbrial adhesin SiiE that mediates intimate contact of Salmonella to microvilli on the apical membrane. Mutant strains lacking SiiE fail to invade polarized cells, to destroy epithelial barrier functions and to efface the apical brush border. Deletion analyses of repetitive domains in SiiE indicate that the large size of the adhesin is of functional importance. Our observations demonstrate that efficient penetration of epithelial barriers requires the cooperative activity of two Salmonella pathogenicity islands encoding different secretion systems. These findings underline the role of the epithelial brush border and reveal a new mechanism used by bacterial pathogens to overcome this barrier.

  15. An Enterotoxin-Bearing Pathogenicity Island in Staphylococcus epidermidis▿†

    PubMed Central

    Madhusoodanan, Jyoti; Seo, Keun Seok; Remortel, Brian; Park, Joo Youn; Hwang, Sun Young; Fox, Lawrence K.; Park, Yong Ho; Deobald, Claudia F.; Wang, Dan; Liu, Song; Daugherty, Sean C.; Gill, Ann Lindley; Bohach, Gregory A.; Gill, Steven R.

    2011-01-01

    Cocolonization of human mucosal surfaces causes frequent encounters between various staphylococcal species, creating opportunities for the horizontal acquisition of mobile genetic elements. The majority of Staphylococcus aureus toxins and virulence factors are encoded on S. aureus pathogenicity islands (SaPIs). Horizontal movement of SaPIs between S. aureus strains plays a role in the evolution of virulent clinical isolates. Although there have been reports of the production of toxic shock syndrome toxin 1 (TSST-1), enterotoxin, and other superantigens by coagulase-negative staphylococci, no associated pathogenicity islands have been found in the genome of Staphylococcus epidermidis, a generally less virulent relative of S. aureus. We show here the first evidence of a composite S. epidermidis pathogenicity island (SePI), the product of multiple insertions in the genome of a clinical isolate. The taxonomic placement of S. epidermidis strain FRI909 was confirmed by a number of biochemical tests and multilocus sequence typing. The genome sequence of this strain was analyzed for other unique gene clusters and their locations. This pathogenicity island encodes and expresses staphylococcal enterotoxin C3 (SEC3) and staphylococcal enterotoxin-like toxin L (SElL), as confirmed by quantitative reverse transcription-PCR (qRT-PCR) and immunoblotting. We present here an initial characterization of this novel pathogenicity island, and we establish that it is stable, expresses enterotoxins, and is not obviously transmissible by phage transduction. We also describe the genome sequence, excision, replication, and packaging of a novel bacteriophage in S. epidermidis FRI909, as well as attempts to mobilize the SePI element by this phage. PMID:21317317

  16. Subtle distinct regulations of late erythroid molecular events by PI3K/AKT-mediated activation of Spi-1/PU.1 oncogene autoregulation loop.

    PubMed

    Breig, O; Théoleyre, O; Douablin, A; Baklouti, F

    2010-05-13

    Spi-1/PU.1 oncogene is downregulated as proerythroblasts undergo terminal differentiation. Insertion of the Friend virus upstream of the Spi-1/PU.1 locus leads to the constitutive upregulation of Spi-1/PU.1, and a subsequent block in the differentiation of the affected erythroblasts. We have shown that sustained overexpression of Spi-1/PU.1 also inhibits the erythroid splicing of protein 4.1R exon 16, irrespective of chemical induction of differentiation. Here, we show a positive feedback loop that couples constitutive phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling to high expression of Spi-1/PU.1 in Friend erythroleukemia cells. Inhibition of PI3K/AKT results in Spi-1/PU.1 downregulation in a stepwise manner and induces cell differentiation. Chromatin immunoprecipitation assays further supported the positive autoregulatory effect of Spi-1/PU.1. Mutational analysis indicated that Ser41, but not Ser148, is necessary for Spi-1/PU.1-mediated repression of hemoglobin expression, whereas both Ser residues are required for Spi-1/PU.1 inhibition of the erythroid splicing event. We further show that inhibition of the erythroid transcriptional and splicing events are strictly dependent on distinct Spi-1/PU.1 phosphorylation modifications rather than Spi-1/PU.1 expression level per se. Our data further support the fact that Spi-1/PU.1 inhibits 4.1R erythroid splicing through two different pathways, and bring new insights into the extracellular signal impact triggered by erythropoietin on late erythroid regulatory program, including pre-mRNA splicing.

  17. A Comprehensive Profile of ChIP-Seq-Based PU.1/Spi1 Target Genes in Microglia.

    PubMed

    Satoh, Jun-Ichi; Asahina, Naohiro; Kitano, Shouta; Kino, Yoshihiro

    2014-01-01

    Microglia are resident mononuclear phagocytes that play a principal role in the maintenance of normal tissue homeostasis in the central nervous system (CNS). Microglia, rapidly activated in response to proinflammatory stimuli, are accumulated in brain lesions of neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. The E26 transformation-specific (ETS) family transcription factor PU.1/Spi1 acts as a master regulator of myeloid and lymphoid development. PU.1-deficient mice show a complete loss of microglia, indicating that PU.1 plays a pivotal role in microgliogenesis. However, the comprehensive profile of PU.1/Spi1 target genes in microglia remains unknown. By analyzing a chromatin immunoprecipitation followed by deep sequencing (ChIP-Seq) dataset numbered SRP036026 with the Strand NGS program, we identified 5,264 Spi1 target protein-coding genes in BV2 mouse microglial cells. They included Spi1, Irf8, Runx1, Csf1r, Csf1, Il34, Aif1 (Iba1), Cx3cr1, Trem2, and Tyrobp. By motif analysis, we found that the PU-box consensus sequences were accumulated in the genomic regions surrounding ChIP-Seq peaks. By using pathway analysis tools of bioinformatics, we found that ChIP-Seq-based Spi1 target genes show a significant relationship with diverse pathways essential for normal function of monocytes/macrophages, such as endocytosis, Fc receptor-mediated phagocytosis, and lysosomal degradation. These results suggest that PU.1/Spi1 plays a crucial role in regulation of the genes relevant to specialized functions of microglia. Therefore, aberrant regulation of PU.1 target genes might contribute to the development of neurodegenerative diseases with accumulation of activated microglia.

  18. A Streptococcus pneumoniae pathogenicity island encoding an ABC transporter involved in iron uptake and virulence.

    PubMed

    Brown, J S; Gilliland, S M; Holden, D W

    2001-05-01

    Restricted iron availability is a major obstacle to growth and survival of pathogenic bacteria during infection. In contrast to Gram-negative pathogens, little is known about how Gram-positive pathogens obtain this essential metal. We have identified two Streptococcus pneumoniae genetic loci, pit1 and pit2, encoding homologues of ABC iron transporters that are required for iron uptake by this organism. S. pneumoniae strains containing disrupted copies of either pit1 or pit2 had decreased sensitivity to the iron-dependent antibiotic streptonigrin, and a strain containing disrupted copies of both pit1 and pit2 was unable to use haemoglobin as an iron source and had a reduced rate of iron uptake. The pit2- strain was moderately and the pit1-/pit2- strain strongly attenuated in virulence in mouse models of pulmonary and systemic infection, showing that the pit loci play a critical role during in vivo growth of S. pneumoniae. The pit2 locus is contained within a 27 kb region of chromosomal DNA that has several features of Gram-negative bacterial pathogenicity islands. This probable pathogenicity island (PPI-1) is the first to be described for S. pneumoniae, and its acquisition is likely to have played a significant role in the evolution of this important human pathogen.

  19. Molecular mechanisms of bacterial virulence: type III secretion and pathogenicity islands.

    PubMed

    Mecsas, J J; Strauss, E J

    1996-01-01

    Recently, two novel but widespread themes have emerged in the field of bacterial virulence: type III secretion systems and pathogenicity islands. Type III secretion systems, which are found in various gram-negative organisms, are specialized for the export of virulence factors delivered directly to host cells. These factors subvert normal host cell functions in ways that seem beneficial to invading bacteria. The genes encoding several type III secretion systems reside on pathogenicity islands, which are inserted DNA segments within the chromosome that confer upon the host bacterium a variety of virulence traits, such as the ability to acquire iron and to adhere to or enter host cells. Many of these segments of DNA appear to have been acquired in a single step from a foreign source. The ability to obtain complex virulence traits in one genetic event, rather than by undergoing natural selection for many generations, provides a mechanism for sudden radical changes in bacterial-host interactions. Type III secretion systems and pathogenicity islands must have played critical roles in the evolution of known pathogens and are likely to lead to the emergence of novel infectious diseases in the future.

  20. A Transmissible Plasmid-Borne Pathogenicity Island Confers Piscibactin Biosynthesis in the Fish Pathogen Photobacterium damselae subsp. piscicida

    PubMed Central

    Rivas, Amable J.; Balado, Miguel; Fuentes-Monteverde, Juan Carlos; Rodríguez, Jaime; Jiménez, Carlos; Lemos, Manuel L.; Waldor, Matthew K.

    2015-01-01

    The fish pathogen Photobacterium damselae subsp. piscicida produces the siderophore piscibactin. A gene cluster that resembles the Yersinia high-pathogenicity island (HPI) encodes piscibactin biosynthesis. Here, we report that this HPI-like cluster is part of a hitherto-uncharacterized 68-kb plasmid dubbed pPHDP70. This plasmid lacks homologs of genes that mediate conjugation, but we found that it could be transferred at low frequencies from P. damselae subsp. piscicida to a mollusk pathogenic Vibrio alginolyticus strain and to other Gram-negative bacteria, likely dependent on the conjugative functions of the coresident plasmid pPHDP60. Following its conjugative transfer, pPHDP70 restored the capacity of a vibrioferrin mutant of V. alginolyticus to grow under low-iron conditions, and piscibactin became detectable in its supernatant. Thus, pPHDP70 appears to harbor all the genes required for piscibactin biosynthesis and transport. P. damselae subsp. piscicida strains cured of pPHDP70 no longer produced piscibactin, had impaired growth under iron-limited conditions, and exhibited markedly decreased virulence in fish. Collectively, our findings highlight the importance of pPHDP70, with its capacity for piscibactin-mediated iron acquisition, in the virulence of P. damselae subsp. piscicida. Horizontal transmission of this plasmid-borne piscibactin synthesis gene cluster in the marine environment may facilitate the emergence of new pathogens. PMID:26092457

  1. Differences in Salmonella enterica serovar Typhimurium strain invasiveness are associated with heterogeneity in SPI-1 gene expression.

    PubMed

    Clark, Leann; Perrett, Charlotte A; Malt, Layla; Harward, Caryn; Humphrey, Suzanne; Jepson, Katy A; Martinez-Argudo, Isabel; Carney, Laura J; La Ragione, Roberto M; Humphrey, Tom J; Jepson, Mark A

    2011-07-01

    Most studies on Salmonella enterica serovar Typhimurium infection focus on strains ATCC SL1344 or NTCC 12023 (ATCC 14028). We have compared the abilities of these strains to induce membrane ruffles and invade epithelial cells. S. Typhimurium strain 12023 is less invasive and induces smaller membrane ruffles on MDCK cells compared with SL1344. Since the SPI-1 effector SopE is present in SL1344 and absent from 12023, and SL1344 sopE mutants have reduced invasiveness, we investigated whether 12023 is less invasive due to the absence of SopE. However, comparison of SopE(+) and SopE(-) S. Typhimurium strains, sopE deletion mutants and 12023 expressing a sopE plasmid revealed no consistent relationship between SopE status and relative invasiveness. Nevertheless, absence of SopE was closely correlated with reduced size of membrane ruffles. A PprgH-gfp reporter revealed that relatively few of the 12023 population (and that of the equivalent strain ATCC 14028) express SPI-1 compared to other S. Typhimurium strains. Expression of a PhilA-gfp reporter mirrored that of PprgH-gfp in 12023 and SL1344, implicating reduced signalling via the transcription factor HilA in the heterogeneous SPI-1 expression of these strains. The previously unrecognized strain heterogeneity in SPI-1 expression and invasiveness has important implications for studies of Salmonella infection.

  2. Genome Sequence of the Fish Pathogen Yersinia ruckeri SC09 Provides Insights into Niche Adaptation and Pathogenic Mechanism

    PubMed Central

    Liu, Tao; Wang, Kai-Yu; Wang, Jun; Chen, De-Fang; Huang, Xiao-Li; Ouyang, Ping; Geng, Yi; He, Yang; Zhou, Yi; Min, Jie

    2016-01-01

    Yersinia ruckeri is the etiologic agent of enteric red mouth disease (ERM), a severe fish disease prevailing in worldwide aquaculture industries. Here we report for the first time the complete genome of Y. ruckeri (Yersinia ruckeri) SC09, a highly virulent strain isolated from Ictalurus punctatus with severe septicemia. SC09 possesses a single chromosome of 3,923,491 base pairs, which contains 3651 predicted protein coding sequences (CDS), 19 rRNA genes, and 79 tRNA genes. Among the CDS, we have identified a Ysa locus containing genes encoding all the components of a type III secretion system (T3SS). Comparative analysis suggest that SC09-Ysa share extensive similarity in sequence, gene content, and gene arrangement with Salmonella enterica pathogenicity island 1 (SPI1) and chromosome-encoded T3SS from Yersinia enterocolitica biotype 1B. Furthermore, phylogenetic analysis shown that SC09-Ysa and SPI1-T3SS belong on the same branch of the phylogenetic tree. These results suggest that SC09-Ysa and SPI1-T3SS appear to mediate biological function to adapt to specific hosts with a similar niche, and both of them are likely to facilitate the development of an intracellular niche. In addition, our analysis also indicated that a substantial part of the SC09 genome might contribute to adaption in the intestinal microenvironment, including a number of proteins associated with aerobic or anaerobic respiration, signal transduction, and various stress reactions. Genomic analysis of the bacterium offered insights into the pathogenic mechanism associated with intracellular infection and intestinal survivability, which constitutes an important first step in understanding the pathogenesis of Y. ruckeri. PMID:27089334

  3. Genome Sequence of the Fish Pathogen Yersinia ruckeri SC09 Provides Insights into Niche Adaptation and Pathogenic Mechanism.

    PubMed

    Liu, Tao; Wang, Kai-Yu; Wang, Jun; Chen, De-Fang; Huang, Xiao-Li; Ouyang, Ping; Geng, Yi; He, Yang; Zhou, Yi; Min, Jie

    2016-01-01

    Yersinia ruckeri is the etiologic agent of enteric red mouth disease (ERM), a severe fish disease prevailing in worldwide aquaculture industries. Here we report for the first time the complete genome of Y. ruckeri (Yersinia ruckeri) SC09, a highly virulent strain isolated from Ictalurus punctatus with severe septicemia. SC09 possesses a single chromosome of 3,923,491 base pairs, which contains 3651 predicted protein coding sequences (CDS), 19 rRNA genes, and 79 tRNA genes. Among the CDS, we have identified a Ysa locus containing genes encoding all the components of a type III secretion system (T3SS). Comparative analysis suggest that SC09-Ysa share extensive similarity in sequence, gene content, and gene arrangement with Salmonella enterica pathogenicity island 1 (SPI1) and chromosome-encoded T3SS from Yersinia enterocolitica biotype 1B. Furthermore, phylogenetic analysis shown that SC09-Ysa and SPI1-T3SS belong on the same branch of the phylogenetic tree. These results suggest that SC09-Ysa and SPI1-T3SS appear to mediate biological function to adapt to specific hosts with a similar niche, and both of them are likely to facilitate the development of an intracellular niche. In addition, our analysis also indicated that a substantial part of the SC09 genome might contribute to adaption in the intestinal microenvironment, including a number of proteins associated with aerobic or anaerobic respiration, signal transduction, and various stress reactions. Genomic analysis of the bacterium offered insights into the pathogenic mechanism associated with intracellular infection and intestinal survivability, which constitutes an important first step in understanding the pathogenesis of Y. ruckeri. PMID:27089334

  4. Role of intraspecies recombination in the spread of pathogenicity islands within the Escherichia coli species.

    PubMed

    Schubert, Sören; Darlu, Pierre; Clermont, Olivier; Wieser, Andreas; Magistro, Giuseppe; Hoffmann, Christiane; Weinert, Kirsten; Tenaillon, Olivier; Matic, Ivan; Denamur, Erick

    2009-01-01

    Horizontal gene transfer is a key step in the evolution of bacterial pathogens. Besides phages and plasmids, pathogenicity islands (PAIs) are subjected to horizontal transfer. The transfer mechanisms of PAIs within a certain bacterial species or between different species are still not well understood. This study is focused on the High-Pathogenicity Island (HPI), which is a PAI widely spread among extraintestinal pathogenic Escherichia coli and serves as a model for horizontal transfer of PAIs in general. We applied a phylogenetic approach using multilocus sequence typing on HPI-positive and -negative natural E. coli isolates representative of the species diversity to infer the mechanism of horizontal HPI transfer within the E. coli species. In each strain, the partial nucleotide sequences of 6 HPI-encoded genes and 6 housekeeping genes of the genomic backbone, as well as DNA fragments immediately upstream and downstream of the HPI were compared. This revealed that the HPI is not solely vertically transmitted, but that recombination of large DNA fragments beyond the HPI plays a major role in the spread of the HPI within E. coli species. In support of the results of the phylogenetic analyses, we experimentally demonstrated that HPI can be transferred between different E. coli strains by F-plasmid mediated mobilization. Sequencing of the chromosomal DNA regions immediately upstream and downstream of the HPI in the recipient strain indicated that the HPI was transferred and integrated together with HPI-flanking DNA regions of the donor strain. The results of this study demonstrate for the first time that conjugative transfer and homologous DNA recombination play a major role in horizontal transfer of a pathogenicity island within the species E. coli.

  5. Mobilization of the Vibrio pathogenicity island between Vibrio cholerae isolates mediated by CP-T1 generalized transduction.

    PubMed

    O'Shea, Yvonne A; Boyd, E Fidelma

    2002-09-10

    Pathogenicity islands are large chromosomal regions encoding virulence genes that were acquired by horizontal gene transfer and are found in a wide range of pathogenic bacteria. In toxigenic Vibrio cholerae isolates the receptor for the cholera toxin encoding filamentous phage CTXphi, the toxin-coregulated pilus, is part of the Vibrio pathogenicity island (VPI). In this paper, we show that the VPI can be transferred between O1 serogroup strains, the predominant cause of epidemic cholera, via a generalized transducing phage CP-T1.

  6. Isolation and characterization of bacteriophage SPI1, which infects the activated-sludge-foaming bacterium Skermania piniformis.

    PubMed

    Dyson, Z A; Tucci, J; Seviour, R J; Petrovski, S

    2016-01-01

    Foaming in activated sludge plants is a worldwide problem commonly caused by proliferation of bacteria of the order Corynebacteriales. These include Skermania piniformis, a filamentous bacterium that has been documented to be a major cause of foaming globally, and particularly in Australian treatment plants. Phage SPI1 is the first phage that was isolated and shown to infect this organism. It targets seven of the nine strains of S. piniformis held in our culture collection, but none of the other 73 mycolata strains of different genera, mostly isolated from wastewater, against which it was tested. Phage SPI1 is a member of the family Siphoviridae and has a circularly permuted dsDNA genome of 55,748 bp with a G+C content of 67.8 mol %. It appears to be obligatorily lytic, with no evidence of genes related to a lysogenic mode of existence. PMID:26459285

  7. Isolation and characterization of bacteriophage SPI1, which infects the activated-sludge-foaming bacterium Skermania piniformis.

    PubMed

    Dyson, Z A; Tucci, J; Seviour, R J; Petrovski, S

    2016-01-01

    Foaming in activated sludge plants is a worldwide problem commonly caused by proliferation of bacteria of the order Corynebacteriales. These include Skermania piniformis, a filamentous bacterium that has been documented to be a major cause of foaming globally, and particularly in Australian treatment plants. Phage SPI1 is the first phage that was isolated and shown to infect this organism. It targets seven of the nine strains of S. piniformis held in our culture collection, but none of the other 73 mycolata strains of different genera, mostly isolated from wastewater, against which it was tested. Phage SPI1 is a member of the family Siphoviridae and has a circularly permuted dsDNA genome of 55,748 bp with a G+C content of 67.8 mol %. It appears to be obligatorily lytic, with no evidence of genes related to a lysogenic mode of existence.

  8. Genetic diversity of Salmonella pathogenicity islands SPI-5 and SPI-6 in Salmonella Newport.

    PubMed

    Cao, Guojie; Allard, Marc; Strain, Errol; Stones, Robert; Zhao, Shaohua; Brown, Eric; Meng, Jianghong

    2014-10-01

    Salmonella enterica subspecies enterica serotype Newport is one of the common serotypes causing foodborne salmonellosis outbreaks in the United States. Salmonella Newport consists of three lineages exhibiting extensive genetic diversity. Due to the importance of Salmonella pathogenicity islands 5 and 6 (SPI-5 and SPI-6) in virulence of pathogenic Salmonella, the genetic diversity of these two SPIs may relate to different potentials of Salmonella Newport pathogenicity. Most Salmonella Newport strains from North America belong to Salmonella Newport lineages II and III. A total 28 Salmonella Newport strains of lineages II and III from diverse sources and geographic locations were analyzed, and 11 additional Salmonella genomes were used as outgroup in phylogenetic analyses. SPI-5 was identified in all Salmonella Newport strains and 146 single nucleotide polymorphisms (SNPs) were detected. Thirty-nine lineage-defining SNPs were identified, including 18 nonsynonymous SNPs. Two 40-kb genomic islands (SPI5-GI1 and SPI5-GI2) encoding bacteriophage genes were found between tRNA-ser and pipA. SPI5-GI1 was only present in Salmonella Newport multidrug-resistant strains of lineage II. SPI-6 was found in all strains but three Asian strains in Salmonella Newport lineage II, whereas the three Asian strains carried genomic island SPI6-GI1 at the same locus as SPI-6 in other Salmonella. SPI-6 exhibited 937 SNPs, and phylogenetic analysis demonstrated that clustering of Salmonella Newport isolates was a reflection of their geographic origins. The sequence diversity within SPI-5 and SPI-6 suggests possible recombination events and different virulence potentials of Salmonella Newport. The SNPs could be used as biomarkers during epidemiological investigations.

  9. Pathogenicity island sequences of pyelonephritogenic Escherichia coli CFT073 are associated with virulent uropathogenic strains.

    PubMed

    Kao, J S; Stucker, D M; Warren, J W; Mobley, H L

    1997-07-01

    Urinary tract infection is the most frequently diagnosed kidney and urologic disease, and Escherichia coli is by far the most common etiologic agent. Defined blocks of DNA termed pathogenicity islands have been found in uropathogenic strains to carry genes not generally found in fecal strains. We have identified one of these regions of DNA within the chromosome of the highly virulent E. coli CFT073, isolated from the blood and urine of a woman with acute pyelonephritis. This strain, which is cytotoxic for cultured renal cells and causes acute pyelonephritis in transurethrally infected CBA mice, contains two distinct copies of the pap operon and is hemolytic. One pap operon was localized on a cosmid clone which was used to identify three overlapping cosmid clones. By using restriction mapping, DNA hybridization, sequencing, and PCR amplification, a region of approximately 50 kb was found to be present in this uropathogenic strain and to have no corresponding sequences in E. coli K-12. This gene block also carries hemolysin genes hlyCABD. The pathogenicity island begins 7 bp downstream of dadX (catabolic alanine racemase; 26.55 min) and ends at a position in the K-12 genome 75 bp downstream of the metV tRNA gene (62.74 min); this suggests that a chromosomal rearrangement has occurred relative to the K-12 linkage map. The junctions of the pathogenicity island were verified by PCR amplification directly from the genomic DNA of strain CFT073. DNA sequencing within the boundaries of the junctions revealed genes not previously identified in E. coli or in some cases bearing no known homologs. When used as probes for DNA hybridization, these sequences were found significantly more often in strains associated with the clinical syndromes of cystitis (82%) and acute pyelonephritis (79%) than in fecal strains (19%; P < 0.001).

  10. Transfer of the cloned Salmonella SPI-1 type III secretion system and characterization of its expression mechanisms in Gram negative bacteria in comparison with cloned SPI-2.

    PubMed

    Cangelosi, Chris; Hannagan, Susan; Santiago, Clayton P; Wilson, James W

    2015-11-01

    Cloned type III secretion systems have much potential to be used for bacterial engineering purposes involving protein secretion and substrate translocation directly into eukaryotic cells. We have previously cloned the SPI-1 and SPI-2 type III systems from the Salmonella enterica serovar Typhimurium genome using plasmid R995 which can conveniently capture large genomic segments for transfer between bacterial strains. However, though expressed and functional in Salmonella strains, cloned SPI-1 was previously observed to have a serious expression defect in other Gram negative bacteria including Escherichia coli. Here we show that cloned SPI-1 expression and secretion can be detected in the secretion preps from E. coli and Citrobacter indicating the first observation of non-Salmonella SPI-1 expression. We describe a compatible plasmid system to introduce engineered SPI-1 substrates into cloned SPI-1 strains. However, a SPI-1 translocation defect is still observed in E. coli, and we show that this is likely due to a defect in SipB expression/secretion in this species. In addition, we also examined the requirement for the hilA and ssrAB regulators in the expression of cloned SPI-1 and SPI-2, respectively. We found a strict requirement for hilA for full cloned SPI-1 expression and secretion. However, though we found that ssrAB is required for full cloned SPI-2 expression in a range of media across different bacteria, it is not required for cloned SPI-2 expression in MgM8 inducing media in S. Typhimurium. This suggests that under SPI-2 inducing conditions in S. Typhimurium, other factors can substitute for loss of ssrAB in cloned SPI-2 expression. The results provide key foundational information for the future use of these cloned systems in bacteria.

  11. Transfer of the cloned Salmonella SPI-1 type III secretion system and characterization of its expression mechanisms in Gram negative bacteria in comparison with cloned SPI-2.

    PubMed

    Cangelosi, Chris; Hannagan, Susan; Santiago, Clayton P; Wilson, James W

    2015-11-01

    Cloned type III secretion systems have much potential to be used for bacterial engineering purposes involving protein secretion and substrate translocation directly into eukaryotic cells. We have previously cloned the SPI-1 and SPI-2 type III systems from the Salmonella enterica serovar Typhimurium genome using plasmid R995 which can conveniently capture large genomic segments for transfer between bacterial strains. However, though expressed and functional in Salmonella strains, cloned SPI-1 was previously observed to have a serious expression defect in other Gram negative bacteria including Escherichia coli. Here we show that cloned SPI-1 expression and secretion can be detected in the secretion preps from E. coli and Citrobacter indicating the first observation of non-Salmonella SPI-1 expression. We describe a compatible plasmid system to introduce engineered SPI-1 substrates into cloned SPI-1 strains. However, a SPI-1 translocation defect is still observed in E. coli, and we show that this is likely due to a defect in SipB expression/secretion in this species. In addition, we also examined the requirement for the hilA and ssrAB regulators in the expression of cloned SPI-1 and SPI-2, respectively. We found a strict requirement for hilA for full cloned SPI-1 expression and secretion. However, though we found that ssrAB is required for full cloned SPI-2 expression in a range of media across different bacteria, it is not required for cloned SPI-2 expression in MgM8 inducing media in S. Typhimurium. This suggests that under SPI-2 inducing conditions in S. Typhimurium, other factors can substitute for loss of ssrAB in cloned SPI-2 expression. The results provide key foundational information for the future use of these cloned systems in bacteria. PMID:26505312

  12. Echoes of a Distant Past: The cag Pathogenicity Island of Helicobacter pylori

    PubMed Central

    Pacchiani, Nicola; Censini, Stefano; Buti, Ludovico; Covacci, Antonello

    2013-01-01

    This review discusses the multiple roles of the CagA protein encoded by the cag pathogenicity island of Helicobacter pylori and highlights the CagA degradation activities on p53. By subverting the p53 tumor suppressor pathway CagA induces a strong antiapoptotic effect. Helicobacter pylori infection has been always associated with an increased risk of gastric cancer. The pro-oncogenic functions of CagA also target the tumor suppressor ASPP2. In the absence of tumor suppressor genes, cells survive and proliferate at times and in places where their survival and proliferation are inappropriate. PMID:24097901

  13. Identification of a pathogenicity island required for Salmonella survival in host cells.

    PubMed Central

    Ochman, H; Soncini, F C; Solomon, F; Groisman, E A

    1996-01-01

    We have identified a region unique to the Salmonella typhimurium chromosome that is essential for virulence in mice. This region harbors at least three genes: two (spiA and spiB) encode products that are similar to proteins found in type III secretion systems, and a third (spiR) encodes a putative regulator. A strain with a mutation in spiA was unable to survive within macrophages but displayed wild-type levels of epithelial cell invasion. The culture supernatants of the spi mutants lacked a modified form of flagellin, which was present in the supernatant of the wild-type strain. This suggests that the Spi secretory apparatus exports a protease, or a protein that can alter the activity of a secreted protease. The "pathogenicity island" harboring the spi genes may encode the virulence determinants that set Salmonella apart from other enteric pathogens. Images Fig. 2 Fig. 4 PMID:8755556

  14. Distribution of Salmonella pathogenicity island (SPI)-8 and SPI-10 among different serotypes of Salmonella.

    PubMed

    Saroj, Sunil D; Shashidhar, R; Karani, Manisha; Bandekar, Jayant R

    2008-04-01

    Many virulence phenotypes of Salmonella enterica are encoded by genes located on pathogenicity islands. Based on genome analysis, it is predicted that Salmonella pathogenicity island (SPI)-8 is restricted to Salmonella serovars Typhi and Paratyphi A, and SPI-10 to Salmonella serovars Typhi, Paratyphi, Enteritidis, Dublin and Gallinarum. This study was conducted to investigate the distribution of SPI-8 and SPI-10 among Salmonella isolates from sprouts, fish, water and blood. A total of 110 Salmonella isolates and 6 Salmonella serovars from the Microbial Type Culture Collection, Chandigarh, India, were screened. All isolates belonging to Salmonella serovars Washington, Enteritidis and Paratyphi A had both SPI-8 and SPI-10. All Salmonella serovar Typhi isolates from water and blood had both SPI-8 and SPI-10, whereas isolates from fish contained only SPI-8. SPI-8 and SPI-10 were also detected in only 3 out of 42 isolates belonging to Salmonella serovar Typhimurium. Both SPI-8 and SPI-10 were absent in Salmonella serovars Worthington, Dublin, Paratyphi B and Paratyphi C. These results contradict the predictions from Salmonella genome sequences available in GenBank and indicate that SPI-8 and SPI-10 are widely distributed among Salmonella serovars and that virulence factors other than those on SPI-8 and SPI-10 may be responsible for host specificity. This is the first report on the distribution of SPIs in Salmonella isolates from India.

  15. Characterization of pathogenicity island prophage in clinical and environmental strains of Vibrio cholerae.

    PubMed

    Mohammadi-Barzelighi, H; Bakhshi, B; Rastegar Lari, A; Pourshafie, M R

    2011-12-01

    In this study 86 isolates of Vibrio cholerae were analysed for their adhesive properties and the presence of pathogenicity island genes. With the exception of three isolates, all of the other clinical isolates (92.5%) contained an intact TCP (toxin-co-regulated pilus) gene cluster. In contrast, 95% of all environmental non-O1-non-O139 isolates were negative for the TCP gene cluster. The majority of clinical isolates (82.5%) possessed the complete vibrio pathogenicity island (VPI) gene cluster and had a similar RFLP pattern, while only a single environmental strain possessed an almost complete VPI cluster (lacking 0.4 kb in the tcpA and toxT region). The result showed that the isolates with tcpA(+)/toxT(+) had a strong attachment for HT-29 and Vero cells, whereas isolates with tcpA(+)/toxT(-) or tcpA(-)/toxT(-) genomic characteristics showed no autoagglutination and weak attachment for the cell lines. Two environmental strains (tcpA(-)/toxT(-)) showed strong adhesive properties to the cell lines, indicating that non-fimbrial adhesive factors are involved in the environmental V. cholerae strains in the absence of TCP.

  16. The Salmonella Pathogenicity Island 13 contributes to pathogenesis in streptomycin pre-treated mice but not in day-old chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella Enteritidis (S. Enteritidis) is a human and animal pathogen that causes gastroenteritis characterized by inflammatory diarrhea and occasionally an invasive systemic infection. Salmonella pathogenicity islands (SPIs) are horizontally acquired genomic segments known to contribute to Salmone...

  17. Sip, an integrase protein with excision, circularization and integration activities, defines a new family of mobile Staphylococcus aureus pathogenicity islands.

    PubMed

    Ubeda, Carles; Tormo, Ma Angeles; Cucarella, Carme; Trotonda, Pilar; Foster, Timothy J; Lasa, Iñigo; Penadés, José R

    2003-07-01

    We report the complete sequence of Staphylococcal pathogenicity island bovine 2 (SaPIbov2), encoding the biofilm-associated protein Bap. SaPIbov2 contains 24 open reading frames, including sip, which encodes a functional staphylococcal integrase protein. SaPIbov2 is bordered by 18 bp direct repeats. The integration site into the chromosome lies at the 3' end of a gene encoding GMP synthase. SaPIbov2 has extensive similarity to previously described pathogenicity islands of Staphylococcus aureus. The principal difference is that toxin genes present in the other pathogenicity islands are exchanged for a transposon-like element that carries the bap gene and genes encoding an ABC transporter and a transposase. Also, SaPIbov2 can be excised to form a circular element and can integrate site-specifically and RecA-independently at a chromosomal att site in a Sip-dependent manner. This was demonstrated both in S. aureus and with plasmid substrates ectopically in Escherichia coli. Thus, SaPIbov2 encodes a functional recombinase of the integrase family that promotes element excision and insertion/integration. In addition, we demonstrated that the presence of SaPIbov2 facilitated the persistence of S. aureus in an intramammary gland infection model. Finally, different bovine isolates of S. aureus were found to carry islands related to SaPIbov2, suggesting the existence of a family of related pathogenicity islands.

  18. Evolution of atypical enteropathogenic E. coli by repeated acquisition of LEE pathogenicity island variants.

    PubMed

    Ingle, Danielle J; Tauschek, Marija; Edwards, David J; Hocking, Dianna M; Pickard, Derek J; Azzopardi, Kristy I; Amarasena, Thakshila; Bennett-Wood, Vicki; Pearson, Jaclyn S; Tamboura, Boubou; Antonio, Martin; Ochieng, John B; Oundo, Joseph; Mandomando, Inácio; Qureshi, Shahida; Ramamurthy, Thandavarayan; Hossain, Anowar; Kotloff, Karen L; Nataro, James P; Dougan, Gordon; Levine, Myron M; Robins-Browne, Roy M; Holt, Kathryn E

    2016-01-18

    Atypical enteropathogenic Escherichia coli (aEPEC) is an umbrella term given to E. coli that possess a type III secretion system encoded in the locus of enterocyte effacement (LEE), but lack the virulence factors (stx, bfpA) that characterize enterohaemorrhagic E. coli and typical EPEC, respectively. The burden of disease caused by aEPEC has recently increased in industrialized and developing nations, yet the population structure and virulence profile of this emerging pathogen are poorly understood. Here, we generated whole-genome sequences of 185 aEPEC isolates collected during the Global Enteric Multicenter Study from seven study sites in Asia and Africa, and compared them with publicly available E. coli genomes. Phylogenomic analysis revealed ten distinct widely distributed aEPEC clones. Analysis of genetic variation in the LEE pathogenicity island identified 30 distinct LEE subtypes divided into three major lineages. Each LEE lineage demonstrated a preferred chromosomal insertion site and different complements of non-LEE encoded effector genes, indicating distinct patterns of evolution of these lineages. This study provides the first detailed genomic framework for aEPEC in the context of the EPEC pathotype and will facilitate further studies into the epidemiology and pathogenicity of EPEC by enabling the detection and tracking of specific clones and LEE variants.

  19. Pathogenicity islands of uropathogenic E. coli and the evolution of virulence.

    PubMed

    Oelschlaeger, T A; Dobrindt, U; Hacker, J

    2002-06-01

    Uropathogenic Escherichia coli (UPEC) are the most important group of microorganisms responsible for urinary tract infection. UPEC differ from non-pathogenic E. coli and from other E. coli pathotypes by the production of specific virulence factors, which enable the bacteria to adhere to uroepithelial cells and to establish urinary tract infections. Besides adherence factors, toxins, 'modulins', capsules, iron uptake systems and other bacterial products contribute to the virulence of the strains. The respective genes are frequently located on large pieces of DNA called 'pathogenicity islands' (PAIs). PAIs form (unstable) regions of the genome of UPECs, which are often associated with tRNA genes. Using various molecular techniques, the functions of PAI encoded gene products have been studied. The usage of DNA arrays give answers to questions on the distribution of PAIs among various enterobacteria and on the expression of the different genes under in vitro and in vivo conditions. In addition, assumptions can be made on the evolution of these important pathogens.

  20. Pathogenicty and immune prophylaxis of cag pathogenicity island gene knockout homogenic mutants

    PubMed Central

    Lin, Huan-Jian; Xue, Jing; Bai, Yang; Wang, Ji-De; Zhang, Ya-Li; Zhou, Dian-Yuan

    2004-01-01

    AIM: To clarify the role of cag pathogenicity island (cagPAI) of Helicobacter pylori (H pylori) in the pathogenicity and immune prophylaxis of H pylori infection. METHODS: Three pairs of H pylori including 3 strains of cagPAI positive wildtype bacteria and their cagPAI knockout homogenic mutants were utilized. H pylori binding to the gastric epithelial cells was analyzed by flow cytometry assays. Apoptosis of gastric epithelial cells induced by H pylori was determined by ELISA assay. Prophylaxis effect of the wildtype and mutant strains was compared by immunization with the sonicate of the bacteria into mice model. RESULTS: No difference was found in the apoptasis between cagPAI positive and knockout H pylori strains in respective of the ability in the binding to gastric epithelial cells as well as the induction of apoptosis. Both types of the bacteria were able to protect the mice from the infection of H pylori after immunization, with no difference between them regarding to the protection rate as well as the stimulation of the proliferation of splenocytes of the mice. CONCLUSION: The role of cagPAI in the pathogenicity and prophylaxis of H pylori infection remains to be cleared. PMID:15484302

  1. Evolution of atypical enteropathogenic E. coli by repeated acquisition of LEE pathogenicity island variants.

    PubMed

    Ingle, Danielle J; Tauschek, Marija; Edwards, David J; Hocking, Dianna M; Pickard, Derek J; Azzopardi, Kristy I; Amarasena, Thakshila; Bennett-Wood, Vicki; Pearson, Jaclyn S; Tamboura, Boubou; Antonio, Martin; Ochieng, John B; Oundo, Joseph; Mandomando, Inácio; Qureshi, Shahida; Ramamurthy, Thandavarayan; Hossain, Anowar; Kotloff, Karen L; Nataro, James P; Dougan, Gordon; Levine, Myron M; Robins-Browne, Roy M; Holt, Kathryn E

    2016-01-01

    Atypical enteropathogenic Escherichia coli (aEPEC) is an umbrella term given to E. coli that possess a type III secretion system encoded in the locus of enterocyte effacement (LEE), but lack the virulence factors (stx, bfpA) that characterize enterohaemorrhagic E. coli and typical EPEC, respectively. The burden of disease caused by aEPEC has recently increased in industrialized and developing nations, yet the population structure and virulence profile of this emerging pathogen are poorly understood. Here, we generated whole-genome sequences of 185 aEPEC isolates collected during the Global Enteric Multicenter Study from seven study sites in Asia and Africa, and compared them with publicly available E. coli genomes. Phylogenomic analysis revealed ten distinct widely distributed aEPEC clones. Analysis of genetic variation in the LEE pathogenicity island identified 30 distinct LEE subtypes divided into three major lineages. Each LEE lineage demonstrated a preferred chromosomal insertion site and different complements of non-LEE encoded effector genes, indicating distinct patterns of evolution of these lineages. This study provides the first detailed genomic framework for aEPEC in the context of the EPEC pathotype and will facilitate further studies into the epidemiology and pathogenicity of EPEC by enabling the detection and tracking of specific clones and LEE variants. PMID:27571974

  2. Spi-1, Fli-1 and Fli-3 (miR-17-92) oncogenes contribute to a single oncogenic network controlling cell proliferation in friend erythroleukemia.

    PubMed

    Kayali, Samer; Giraud, Guillaume; Morlé, François; Guyot, Boris

    2012-01-01

    Clonal erythroleukemia developing in susceptible mice infected by Friend virus complex are associated with highly recurrent proviral insertions at one of three loci called Spi-1, Fli-1 or Fli-3, leading to deregulated expression of oncogenic Spi-1 or Fli-1 transcription factors or miR-17-92 miRNA cluster, respectively. Deregulated expression of each of these three oncogenes has been independently shown to contribute to cell proliferation of erythroleukemic clones. Previous studies showed a close relationship between Spi-1 and Fli-1, which belong to the same ETS family, Spi-1 activating fli-1 gene, and both Spi-1 and Fli-1 activating multiple common target genes involved in ribosome biogenesis. In this study, we demonstrated that Spi-1 and Fli-1 are also involved in direct miR-17-92 transcriptional activation through their binding to a conserved ETS binding site in its promoter. Moreover, we demonstrated that physiological re-expression of exogenous miR-17 and miR-20a are able to partially rescue the proliferation loss induced by Fli-1 knock-down and identified HBP1 as a target of these miRNA in erythroleukemic cells. These results establish that three of the most recurrently activated oncogenes in Friend erythroleukemia are actually involved in a same oncogenic network controlling cell proliferation. The putative contribution of a similar ETS-miR-17-92 network module in other normal or pathological proliferative contexts is discussed.

  3. Two pathogenicity islands in uropathogenic Escherichia coli J96: cosmid cloning and sample sequencing.

    PubMed

    Swenson, D L; Bukanov, N O; Berg, D E; Welch, R A

    1996-09-01

    Many of the virulence genes of pathogenic strains of Escherichia coli are carried in large multigene chromosomal segments called pathogenicity islands (PAIs) that are absent from normal fecal and laboratory K-12 strains of this bacterium. We are studying PAIs in order to better understand factors that govern virulence and to assess how such DNA segments are gained or lost during evolution. The isolation and sample sequencing of a set of 11 cosmid clones that cover all of one and much of a second large PAI in the uropathogenic E. coli J96 are described. These PAIs were mapped to the 64- and 94-min regions of the E. coli K-12 chromosome, which differ from the locations of three PAIs identified in other pathogenic E. coli strains. Analysis of the junction sequences with E. coli K-12-like DNAs showed that the insert at 94 min is within the 3' end of a phenylalanine tRNA gene, pheR, and is flanked by a 135-bp imperfect direct repeat. Analysis of the one junction recovered from the insert at 64 min indicated that it lies near another tRNA gene, pheV. To identify possible genes unique to these PAIs, 100 independent subclones of the cosmids were made by PstI digestion and ligation into a pBS+ plasmid and used in one-pass sample DNA sequencing from primer binding sites at the cloning site in the vector DNA. Database searches of the J96 PAI-specific sequences identified numerous instances in which the cloned DNAs shared significant sequence similarities to adhesins, toxins, and other virulence determinants of diverse pathogens. Several likely insertion sequence elements (IS100, IS630, and IS911) and conjugative R1 plasmid and P4 phage genes were also found. We propose that such mobile genetic elements may have facilitated the spread of virulence determinants within PAIs among bacteria.

  4. Excision of the Shigella Resistance Locus Pathogenicity Island in Shigella flexneri Is Stimulated by a Member of a New Subgroup of Recombination Directionality Factors

    PubMed Central

    Luck, Shelley N.; Turner, Sally A.; Rajakumar, Kumar; Adler, Ben; Sakellaris, Harry

    2004-01-01

    Pathogenicity islands are capable of excision and insertion within bacterial chromosomes. We describe a protein, Rox, that stimulates excision of the Shigella resistance locus pathogenicity island in Shigella flexneri. Sequence analysis suggests that Rox belongs to a new subfamily of recombination directionality factors, which includes proteins from P4, enterohemorrhagic Escherichia coli, and Yersinia pestis. PMID:15292162

  5. Downregulation of the Spi-1/PU.1 oncogene induces the expression of TRIM10/HERF1, a key factor required for terminal erythroid cell differentiation and survival.

    PubMed

    Blaybel, Rand; Théoleyre, Orianne; Douablin, Alexandre; Baklouti, Faouzi

    2008-08-01

    Sustained expression of the Spi-1/PU.1 and Fli-1 oncoproteins blocks globin gene activation in mouse erythroleukemia cells; however, only Spi-1/PU.1 expression inhibits the inclusion of exon 16 in the mature 4.1R mRNA. This splicing event is crucial for a functional 4.1R protein and, therefore, for red blood cell membrane integrity. This report demonstrates that Spi-1/PU.1 downregulation induces the activation of TRIM10/hematopoietic RING finger 1 (HERF1), a member of the tripartite motif (TRIM)/RBCC protein family needed for globin gene transcription. Additionally, we demonstrate that TRIM10/HERF1 is required for the regulated splicing of exon 16 during late erythroid differentiation. Using inducible overexpression and silencing approaches, we found that: (1) TRIM10/HERF1 knockdown inhibits hemoglobin production and exon splicing and triggers cell apoptosis in dimethylsulfoxide (DMSO)-induced cells; (2) TRIM10/HERF1 upregulation is required but is insufficient on its own to activate exon retention; (3) Fli-1 has no effect on TRIM10/HERF1 expression, whereas either DMSO-induced downregulation or shRNA-knockdown of Spi-1/PU.1 expression is sufficient to activate TRIM10/HERF1 expression; and (4) Spi-1/PU.1 knockdown triggers both the transcription and the splicing events independently of the chemical induction. Altogether, these data indicate that primary Spi-1/PU.1 downregulation acts on late erythroid differentiation through at least two pathways, one of which requires TRIM10/HERF1 upregulation and parallels the Spi-1/PU.1-induced Fli-1 shutoff regulatory cascade.

  6. Dual regulation of SPI1/PU.1 transcription factor by heat shock factor 1 (HSF1) during macrophage differentiation of monocytes.

    PubMed

    Jego, G; Lanneau, D; De Thonel, A; Berthenet, K; Hazoumé, A; Droin, N; Hamman, A; Girodon, F; Bellaye, P-S; Wettstein, G; Jacquel, A; Duplomb, L; Le Mouël, A; Papanayotou, C; Christians, E; Bonniaud, P; Lallemand-Mezger, V; Solary, E; Garrido, C

    2014-08-01

    In addition to their cytoprotective role in stressful conditions, heat shock proteins (HSPs) are involved in specific differentiation pathways, for example, we have identified a role for HSP90 in macrophage differentiation of human peripheral blood monocytes that are exposed to macrophage colony-stimulating factor (M-CSF). Here, we show that deletion of the main transcription factor involved in heat shock gene regulation, heat shock factor 1 (HSF1), affects M-CSF-driven differentiation of mouse bone marrow cells. HSF1 transiently accumulates in the nucleus of human monocytes undergoing macrophage differentiation, including M-CSF-treated peripheral blood monocytes and phorbol ester-treated THP1 cells. We demonstrate that HSF1 has a dual effect on SPI1/PU.1, a transcription factor essential for macrophage differentiation and whose deregulation can lead to the development of leukemias and lymphomas. Firstly, HSF1 regulates SPI1/PU.1 gene expression through its binding to a heat shock element within the intron 2 of this gene. Furthermore, downregulation or inhibition of HSF1 impaired both SPI1/PU.1-targeted gene transcription and macrophage differentiation. Secondly, HSF1 induces the expression of HSP70 that interacts with SPI1/PU.1 to protect the transcription factor from proteasomal degradation. Taken together, HSF1 appears as a fine-tuning regulator of SPI1/PU.1 expression at the transcriptional and post-translational levels during macrophage differentiation of monocytes.

  7. Presence of pathogenicity islands and virulence genes of extraintestinal pathogenic Escherichia coli (ExPEC) in isolates from avian organic fertilizer.

    PubMed

    Gazal, Luís Eduardo S; Puño-Sarmiento, Juan J; Medeiros, Leonardo P; Cyoia, Paula S; da Silveira, Wanderlei D; Kobayashi, Renata K T; Nakazato, Gerson

    2015-12-01

    Poultry litter is commonly used as fertilizer in agriculture. However, this poultry litter must be processed prior to use, since poultry have a large number of pathogenic microorganisms. The aims of this study were to isolate and genotypically and phenotypically characterize Escherichia coli from avian organic fertilizer. Sixty-four E. coli isolates were identified from avian organic fertilizer and characterized for ExPEC virulence factors, pathogenicity islands, phylogenetic groups, antimicrobial resistance, biofilm formation, and adhesion to HEp-2 cells. Sixty-three isolates (98.4%) showed at least one virulence gene (fimH, ecpA, sitA, traT, iutA, iroN, hlyF, ompT and iss). The predominant phylogenetic groups were groups A (59.3%) and B1 (34.3%). The pathogenicity island CFT073II (51.5%) was the most prevalent among the isolates tested. Thirty-two isolates (50%) were resistant to at least one antimicrobial agent. Approximately 90% of isolates adhered to HEp-2 cells, and the predominant pattern was aggregative adherence (74.1%). In the biofilm assay, it was observed that 75% of isolates did not produce biofilm. These results lead us to conclude that some E. coli isolates from avian organic fertilizer could be pathogenic for humans. PMID:26476087

  8. Presence of pathogenicity islands and virulence genes of extraintestinal pathogenic Escherichia coli (ExPEC) in isolates from avian organic fertilizer.

    PubMed

    Gazal, Luís Eduardo S; Puño-Sarmiento, Juan J; Medeiros, Leonardo P; Cyoia, Paula S; da Silveira, Wanderlei D; Kobayashi, Renata K T; Nakazato, Gerson

    2015-12-01

    Poultry litter is commonly used as fertilizer in agriculture. However, this poultry litter must be processed prior to use, since poultry have a large number of pathogenic microorganisms. The aims of this study were to isolate and genotypically and phenotypically characterize Escherichia coli from avian organic fertilizer. Sixty-four E. coli isolates were identified from avian organic fertilizer and characterized for ExPEC virulence factors, pathogenicity islands, phylogenetic groups, antimicrobial resistance, biofilm formation, and adhesion to HEp-2 cells. Sixty-three isolates (98.4%) showed at least one virulence gene (fimH, ecpA, sitA, traT, iutA, iroN, hlyF, ompT and iss). The predominant phylogenetic groups were groups A (59.3%) and B1 (34.3%). The pathogenicity island CFT073II (51.5%) was the most prevalent among the isolates tested. Thirty-two isolates (50%) were resistant to at least one antimicrobial agent. Approximately 90% of isolates adhered to HEp-2 cells, and the predominant pattern was aggregative adherence (74.1%). In the biofilm assay, it was observed that 75% of isolates did not produce biofilm. These results lead us to conclude that some E. coli isolates from avian organic fertilizer could be pathogenic for humans.

  9. The irp2 and fyuA genes in High Pathogenicity Islands are involved in the pathogenesis of infections caused by avian pathogenic Escherichia coli (APEC).

    PubMed

    Tu, Jian; Xue, Ting; Qi, Kezong; Shao, Ying; Huang, Boyan; Wang, Xueyan; Zhou, Xiuhong

    2016-01-01

    Avian pathogenic Escherichia coli (APEC) is a major bacterial infectious disease that may lead to local or systemic infections in chickens with clinical manifestations. The irp2-fyuA gene cluster has been confirmed to be the main genes involved in the synthesis of HPI. The objective of this study was to determine the influence of the irp2 and fyuA genes in the high pathogenicity island (HPI) of avian pathogenic Escherichia coli (APEC) on its pathogenicity by knocking out these genes. The ΔAE17 (lacking irp2) and ΔΔAE17 (lacking irp2 and fyuA) strains of APEC were constructed. The ΔAE17 and ΔΔAE17 strains showed significantly impaired capacity to adhere onto DF-1 cells. The LD50 results indicated that the virulence of the ΔAE17 and ΔΔAE17 strains was decreased in comparison with that of the AE17 strain. We concluded that the knock-out of the core HPI genes weakened APEC adhesion onto DF-1 cells, inhibited transcription of virulence genes, and reduced pathogenicity in chicks. The effects of genetic deletion of irp2 and fyuA on APEC were more severe than those produced by deletion of irp2 only, indicating that irp2 and fyuA co-regulate APEC pathogenicity.

  10. Prevalence of Avian-Pathogenic Escherichia coli Strain O1 Genomic Islands among Extraintestinal and Commensal E. coli Isolates

    PubMed Central

    Johnson, Timothy J.; Wannemuehler, Yvonne; Kariyawasam, Subhashinie; Johnson, James R.; Logue, Catherine M.

    2012-01-01

    Escherichia coli strains that cause disease outside the intestine are known as extraintestinal pathogenic E. coli (ExPEC) and include pathogens of humans and animals. Previously, the genome of avian-pathogenic E. coli (APEC) O1:K1:H7 strain O1, from ST95, was sequenced and compared to those of several other E. coli strains, identifying 43 genomic islands. Here, the genomic islands of APEC O1 were compared to those of other sequenced E. coli strains, and the distribution of 81 genes belonging to 12 APEC O1 genomic islands among 828 human and avian ExPEC and commensal E. coli isolates was determined. Multiple islands were highly prevalent among isolates belonging to the O1 and O18 serogroups within phylogenetic group B2, which are implicated in human neonatal meningitis. Because of the extensive genomic similarities between APEC O1 and other human ExPEC strains belonging to the ST95 phylogenetic lineage, its ability to cause disease in a rat model of sepsis and meningitis was assessed. Unlike other ST95 lineage strains, APEC O1 was unable to cause bacteremia or meningitis in the neonatal rat model and was significantly less virulent than uropathogenic E. coli (UPEC) CFT073 in a mouse sepsis model, despite carrying multiple neonatal meningitis E. coli (NMEC) virulence factors and belonging to the ST95 phylogenetic lineage. These results suggest that host adaptation or genome modifications have occurred either in APEC O1 or in highly virulent ExPEC isolates, resulting in differences in pathogenicity. Overall, the genomic islands examined provide targets for further discrimination of the different ExPEC subpathotypes, serogroups, phylogenetic types, and sequence types. PMID:22467781

  11. Identification of a genomic island present in the majority of pathogenic isolates of Pseudomonas aeruginosa.

    PubMed

    Liang, X; Pham, X Q; Olson, M V; Lory, S

    2001-02-01

    Pseudomonas aeruginosa, a ubiquitous gram-negative bacterium, is capable of colonizing a wide range of environmental niches and can also cause serious infections in humans. In order to understand the genetic makeup of pathogenic P. aeruginosa strains, a method of differential hybridization of arrayed libraries of cloned DNA fragments was developed. An M13 library of DNA from strain X24509, isolated from a patient with a urinary tract infection, was screened using a DNA probe from P. aeruginosa strain PAO1. The genome of PAO1 has been recently sequenced and can be used as a reference for comparisons of genetic organization in different strains. M13 clones that did not react with a DNA probe from PAO1 carried X24509-specific inserts. When a similar array hybridization analysis with DNA probes from different strains was used, a set of M13 clones which carried sequences present in the majority of human P. aeruginosa isolates from a wide range of clinical sources was identified. The inserts of these clones were used to identify cosmids encompassing a contiguous 48.9-kb region of the X24509 chromosome called PAGI-1 (for "P. aeruginosa genomic island 1"). PAGI-1 is incorporated in the X24509 chromosome at a locus that shows a deletion of a 6,729-bp region present in strain PAO1. Survey of the incidence of PAGI-1 revealed that this island is present in 85% of the strains from clinical sources. Approximately half of the PAGI-1-carrying strains show the same deletion as X24509, while the remaining strains contain both the PAGI-1 sequences and the 6,729-bp PAO1 segment. Sequence analysis of PAGI-1 revealed that it contains 51 predicted open reading frames. Several of these genes encoded products with predictable function based on their sequence similarities to known genes, including insertion sequences, determinants of regulatory proteins, a number of dehydrogenase gene homologs, and two for proteins of implicated in detoxification of reactive oxygen species. It is very

  12. Salmonella Pathogenicity Island 2 Influences Both Systemic Salmonellosis and Salmonella-Induced Enteritis in Calves

    PubMed Central

    Bispham, J.; Tripathi, B. N.; Watson, P. R.; Wallis, T. S.

    2001-01-01

    We have used signature-tagged mutagenesis to identify mutants of the host-specific Salmonella enterica serotype Dublin which were avirulent in calves and/or BALB/c mice. A mutant with a transposon insertion in the sseD gene of Salmonella pathogenicity island 2 (SPI-2), which encodes a putative secreted effector protein, was identified. This mutant was recovered from the bovine host but not from the murine host following infection with a pool of serotype Dublin mutants. However, a pure inoculum of the sseD mutant was subsequently shown to be attenuated in calves following infection either by the intravenous route or by the oral route. The sseD mutant was fully invasive for bovine intestinal mucosa but was subsequently unable to proliferate to the same numbers as the parental strain in vivo. Both the sseD mutant and a second SPI-2 mutant, with a transposon insertion in the ssaT gene, induced significantly weaker secretory and inflammatory responses in bovine ligated ileal loops than did the parental strain. These results demonstrate that SPI-2 is required by serotype Dublin for the induction of both systemic and enteric salmonellosis in calves. PMID:11119526

  13. Excision of an unstable pathogenicity island in Salmonella enterica serovar Enteritidis is induced during infection of phagocytic cells.

    PubMed

    Quiroz, Tania S; Nieto, Pamela A; Tobar, Hugo E; Salazar-Echegarai, Francisco J; Lizana, Rodrigo J; Quezada, Carolina P; Santiviago, Carlos A; Araya, Daniela V; Riedel, Claudia A; Kalergis, Alexis M; Bueno, Susan M

    2011-01-01

    The availability of the complete genome sequence of several Salmonella enterica serovars has revealed the presence of unstable genetic elements in these bacteria, such as pathogenicity islands and prophages. This is the case of Salmonella enterica serovar Enteritidis (S. Enteritidis), a bacterium that causes gastroenteritis in humans and systemic infection in mice. The whole genome sequence analysis for S. Enteritidis unveiled the presence of several genetic regions that are absent in other Salmonella serovars. These regions have been denominated "regions of difference" (ROD). In this study we show that ROD21, one of such regions, behaves as an unstable pathogenicity island. We observed that ROD21 undergoes spontaneous excision by two independent recombination events, either under laboratory growth conditions or during infection of murine cells. Importantly, we also found that one type of excision occurred at higher rates when S. Enteritidis was residing inside murine phagocytic cells. These data suggest that ROD21 is an unstable pathogenicity island, whose frequency of excision depends on the environmental conditions found inside phagocytic cells.

  14. Distribution of pathogenicity island markers in commensal and uropathogenic Escherichia coli isolates.

    PubMed

    Samei, Ali; Haghi, Fakhri; Zeighami, Habib

    2016-05-01

    Uropathogenic Escherichia coli (UPEC) isolates contain large genomic segments, termed pathogenicity islands (PAIs), that contribute to their virulence. A total of 150 UPEC and 50 commensal E. coli isolates from outpatients were investigated for antimicrobial susceptibility and the presence of eight PAI markers. One hundred ninety (95 %) isolates were resistant to one or more antimicrobial agents. The most frequent resistance found against amoxicillin (68 %), amoxicillin/clavulanic acid (55 %), aztreonam (50 %), trimethoprim/sulfamethoxazole (46 %) and tetracycline (43.5 %). Antimicrobial resistance among UPEC isolates was higher than that of commensals. PAI markers were detected in substantial percentage of commensal (88 %) and UPEC isolates (98.6 %) (P > 0.05). The most prevalent PAI marker among UPEC and commensal isolates was PAI IV536 (98.7 % UPEC vs. 84 % commensal). We found a high number of PAI markers such as PAI ICFT073, PAI IICFT073, PAI I536, PAI II536, PAI III536 and PAI IIJ96 significantly associated with UPEC. PAI III536 (21.3 %) and PAI IIJ96 (8 %) were detected only in the uropathogenic isolates. Several different combinations of PAIs were found among UPEC isolates. Comparison of PAIs among UPEC and commensal isolates showed that many UPEC isolates (79.3 %) carried two or more PAI markers, while 6 % of commensals had two PAI markers (P < 0.05). The most frequent combinations of PAI markers in UPEC isolates were PAI IV536 + PAI IICFT073 (18 %) and PAI IV536 + PAI ICFT073 + PAI IICFT073 (18 %). These results indicate that PAI markers are widespread among commensal and UPEC isolates and these commensal isolates may be reservoirs for transmission of these markers.

  15. Delineation of upstream signaling events in the salmonella pathogenicity island 2 transcriptional activation pathway.

    PubMed

    Kim, Charles C; Falkow, Stanley

    2004-07-01

    Survival and replication in the intracellular environment are critical components of the ability of Salmonella enterica serovar Typhimurium to establish systemic infection in the murine host. Intracellular survival is mediated by a number of genetic loci, including Salmonella pathogenicity island 2 (SPI2). SPI2 is a 40-kb locus encoding a type III secretion system that secretes effector molecules, which permits bacterial survival and replication in the intracellular environment of host cells. A two-component regulatory system, ssrAB, is also encoded in SPI2 and controls expression of the secretion system and effectors. While the environmental signals to which SPI2 responds in vivo are not known, activation of expression is dependent on OmpR and can be stimulated in vitro by chelation of cations or by a shift from rich to acidic minimal medium. In this work, we demonstrated that SPI2 activation is associated with OmpR in the phosphorylated form (OmpR-P). Mutations in envZ and ackA-pta, which disrupted two distinct sources of OmpR phosphorylation, indicated that SPI2 activation by chelators or a shift from rich to acidic minimal medium is largely dependent on functional EnvZ. In contrast, the PhoPQ pathway is not required for SPI2 activation in the presence of OmpR-P. As in the case of in vitro stimulation, SPI2 expression in macrophages correlates with the presence of OmpR-P. Additionally, EnvZ, but not acetyl phosphate, is required for maximal expression of SPI2 in the intracellular environment, suggesting that the in vitro SPI2 activation pathway is the same as that used in vivo.

  16. NATURAL ATYPICAL LISTERIA INNOCUA STRAINS WITH LISTERIA MONOCYTOGENES PATHOGENICITY ISLAND 1 GENES

    EPA Science Inventory

    The detection of the human foodborne pathogen, Listeria monocytogenes, in food, environmental samples and clinical specimens associated with cases of listeriosis, a rare but high mortality-rate disease, requires distinguishing the pathogen from other Listeria species. Speciation...

  17. A Novel Pathogenicity Island Integrated Adjacent to the thrW tRNA Gene of Avian Pathogenic Escherichia coli Encodes a Vacuolating Autotransporter Toxin

    PubMed Central

    Parreira, V. R.; Gyles, C. L.

    2003-01-01

    We report the complete nucleotide sequence and genetic organization of the Vat-encoding pathogenicity island (PAI) of avian pathogenic Escherichia coli strain Ec222. The 22,139-bp PAI is situated adjacent to the 3′ terminus of the thrW tRNA gene, has a G+C content of 41.2%, and includes a bacteriophage SfII integrase gene, mobile genetic elements, two open reading frames with products exhibiting sequence similarity to known proteins, and several other open reading frames of unknown function. The PAI encodes an autotransporter protein, Vat (vacuolating autotransporter toxin), which induces the formation of intracellular vacuoles resulting in cytotoxic effects similar to those caused by the VacA toxin from Helicobacter pylori. The predicted 148.3-kDa protein product possesses the three domains that are typical of serine protease autotransporters of Enterobacteriaceae: an N-terminal signal sequence of 55 amino acids, a 111.8-kDa passenger domain containing a modified serine protease site (ATSGSG), and a C-terminal outer membrane translocator of 30.5 kDa. Vat has 75% protein homology with the hemagglutinin Tsh, an autotransporter of avian pathogenic E. coli. A vat deletion mutant of Ec222 showed no virulence in respiratory and cellulitis infection models of disease in broiler chickens. We conclude that the newly described PAI and Vat may be involved in the pathogenicity of avian septicemic E. coli strain Ec222 and other avian pathogenic E. coli strains. PMID:12933851

  18. New protein fold revealed by a 1.65 Å resolution crystal structure of Francisella tularensis pathogenicity island protein IglC

    PubMed Central

    Sun, Ping; Austin, Brian P.; Schubot, Florian D.; Waugh, David S.

    2007-01-01

    Francisella tularensis is a highly infectious Gram-negative intracellular pathogen that causes the fulminating disease tularemia and is considered to be a potential bioweapon. F. tularensis pathogenicity island proteins play a key role in modulating phagosome biogenesis and subsequent bacterial escape into the cytoplasm of macrophages. The 23 kDa pathogenicity island protein IglC is essential for the survival and proliferation of F. tularensis in macrophages. Seeking to gain some insight into its function, we determined the crystal structure of IglC at 1.65 Å resolution. IglC adopts a β-sandwich conformation that exhibits no similarity with any known protein structure. PMID:17905833

  19. Phylogenetic Analysis and Prevalence of Urosepsis Strains of Escherichia coli Bearing Pathogenicity Island-Like Domains

    PubMed Central

    Bingen-Bidois, Martine; Clermont, Olivier; Bonacorsi, Stéphane; Terki, Mustapha; Brahimi, Naïma; Loukil, Chawki; Barraud, Dominique; Bingen, Edouard

    2002-01-01

    We characterized 100 Escherichia coli urosepsis isolates from adult patients according to host compromise status by means of ribotyping, PCR phylogenetic grouping, and PCR detection of papG alleles and the virulence-related genes sfa/foc, fyuA, irp-2, aer, hly, cnf-1 and hra. We also tested these strains for copies of pap and hly and their direct physical linkage with other virulence genes in an attempt to look for pathogenicity islands (PAIs) described for the archetypal uropathogenic strains J96, CFT073, and 536. Most of the isolates belonged to E. coli phylogenetic groups B2 and D and bore papG allele II, aer, and fyuA/irp-2. papG allele II-bearing strains were more common in noncompromised patients, while papG allele-negative strains were significantly more frequent in compromised patients. Fifteen ribotypes were identified. The three archetypal strains harbored different ribotypes, and only one-third of our urosepsis strains were genetically related to one of the archetypal strains. Three and 18 strains harbored three and two copies of pap, respectively, and 5 strains harbored two copies of hly. papGIII was physically linked to hly, cnf-1, and hra (reported to be PAI IIJ96-like genetic elements) in 14% of the strains. The PAI IIJ96-like domain was inserted within pheR tRNA in 11 strains and near leuX tRNA in 3 strains. Moreover, the colocalized genes cnf-1, hra, and hly were physically linked to papGII in four strains and to no pap gene in three strains. papGII and hly (reported to be PAI ICFT073-like genetic elements) were physically linked in 16 strains, pointing to a PAI ICFT073-like domain. Three strains contained both a PAI IIJ96-like domain and a PAI ICFTO73-like domain. Forty-two strains harbored papGII but not hly, in keeping with the presence of a PAI IICFT073-like domain. Only one strain harbored a PAI I536-like domain (hly only), and none harbored a PAI IJ96-like domain (papGI plus hly) or a PAI II536-like domain (papGIII plus hly). This study

  20. Functional analysis of pyochelin-/enantiopyochelin-related genes from a pathogenicity island of Pseudomonas aeruginosa strain PA14.

    PubMed

    Maspoli, Alessandro; Wenner, Nicolas; Mislin, Gaëtan L A; Reimmann, Cornelia

    2014-06-01

    Genomic islands are foreign DNA blocks inserted in so-called regions of genomic plasticity (RGP). Depending on their gene content, they are classified as pathogenicity, symbiosis, metabolic, fitness or resistance islands, although a detailed functional analysis is often lacking. Here we focused on a 34-kb pathogenicity island of Pseudomonas aeruginosa PA14 (PA14GI-6), which is inserted at RGP5 and carries genes related to those for pyochelin/enantiopyochelin biosynthesis. These enantiomeric siderophores of P. aeruginosa and certain strains of Pseudomonas protegens are assembled by a thiotemplate mechanism from salicylate and two molecules of cysteine. The biochemical function of several proteins encoded by PA14GI-6 was investigated by a series of complementation analyses using mutants affected in potential homologs. We found that PA14_54940 codes for a bifunctional salicylate synthase/salicyl-AMP ligase (for generation and activation of salicylate), that PA14_54930 specifies a dihydroaeruginoic acid (Dha) synthetase (for coupling salicylate with a cysteine-derived thiazoline ring), that PA14_54910 produces a type II thioesterase (for quality control), and that PA14_54880 encodes a serine O-acetyltransferase (for increased cysteine availability). The structure of the PA14GI-6-specified metabolite was determined by mass spectrometry, thin-layer chromatography, and HPLC as (R)-Dha, an iron chelator with antibacterial, antifungal and antitumor activity. The conservation of this genomic island in many clinical and environmental P. aeruginosa isolates of different geographical origin suggests that the ability for Dha production may confer a selective advantage to its host. PMID:24682869

  1. phoP, SPI1, SPI2 and aroA mutants of Salmonella Enteritidis induce a different immune response in chickens.

    PubMed

    Elsheimer-Matulova, Marta; Varmuzova, Karolina; Kyrova, Kamila; Havlickova, Hana; Sisak, Frantisek; Rahman, Masudur; Rychlik, Ivan

    2015-01-01

    Poultry is the most frequent reservoir of non-typhoid Salmonella enterica for humans. Understanding the interactions between chickens and S. enterica is therefore important for vaccine design and subsequent decrease in the incidence of human salmonellosis. In this study we therefore characterized the interactions between chickens and phoP, aroA, SPI1 and SPI2 mutants of S. Enteritidis. First we tested the response of HD11 chicken macrophage-like cell line to S. Enteritidis infection monitoring the transcription of 36 genes related to immune response. All the mutants and the wild type strain induced inflammatory signaling in the HD11 cell line though the response to SPI1 mutant infection was different from the rest of the mutants. When newly hatched chickens were inoculated, the phoP as well as the SPI1 mutant did not induce an expression of any of the tested genes in the cecum. Despite this, such chickens were protected against challenge with wild-type S. Enteritidis. On the other hand, inoculation of chickens with the aroA or SPI2 mutant induced expression of 27 and 18 genes, respectively, including genes encoding immunoglobulins. Challenge of chickens inoculated with these two mutants resulted in repeated induction of 11 and 13 tested genes, respectively, including the genes encoding immunoglobulins. In conclusion, SPI1 and phoP mutants induced protective immunity without inducing an inflammatory response and antibody production. Inoculation of chickens with the SPI2 and aroA mutants also led to protective immunity but was associated with inflammation and antibody production. The differences in interaction between the mutants and chicken host can be used for a more detailed understanding of the chicken immune system.

  2. Molecular characterization of a widespread, pathogenic, and antibiotic resistance-receptive Enterococcus faecalis lineage and dissemination of its putative pathogenicity island.

    PubMed

    Nallapareddy, Sreedhar R; Wenxiang, Huang; Weinstock, George M; Murray, Barbara E

    2005-08-01

    Enterococcus faecalis, a common cause of endocarditis and known for its capacity to transfer antibiotic resistance to other pathogens, has recently emerged as an important, multidrug-resistant nosocomial pathogen. However, knowledge of its lineages and the potential of particular clones of this species to disseminate and cause disease is limited. Using a nine-gene multilocus sequence typing (MLST) scheme, we identified an evolving and widespread clonal complex of E. faecalis that has caused outbreaks and life-threatening infections. Moreover, this unusual clonal complex was found to contain isolates of unexpected relatedness, including the first known U.S. vancomycin-resistant enterococcus (E. faecalis strain V583), the first known penicillinase-producing (Bla(+)) E. faecalis isolate, and the previously described widespread clone of penicillinase producers, a trait found in <0.1% of E. faecalis isolates. All members of this clonal cluster (designated as BVE for Bla(+) Van(r) endocarditis) were found to contain a previously described putative pathogenicity island (PAI). Further analysis of this PAI demonstrated its dissemination worldwide, albeit with considerable variability, confirmed its association with clinical isolates, and found a common insertion site in different clonal lineages. PAI deletions, MLST, and the uncommon resistances were used to predict the evolution of the BVE clonal cluster. The finding of a virulent and highly successful clonal complex of E. faecalis with different members resistant to the primary therapies of choice, ampicillin and vancomycin, has important implications for the evolution of virulence and successful lineages and for public health monitoring and control.

  3. The SPI1 gene, encoding a glycosylphosphatidylinositol-anchored cell wall protein, plays a prominent role in the development of yeast resistance to lipophilic weak-acid food preservatives.

    PubMed

    Simões, T; Mira, N P; Fernandes, A R; Sá-Correia, Isabel

    2006-11-01

    The Saccharomyces cerevisiae SPI1 gene encodes a member of the glycosylphosphatidylinositol-anchored cell wall protein family. In this work we show results indicating that SPI1 expression protects the yeast cell from damage caused by weak acids used as food preservatives. This is documented by a less extended period of adaptation to growth in their presence and by a less inhibited specific growth rate for a parental strain compared with a mutant with SPI1 deleted. Maximal protection exerted by Spi1p against equivalent concentrations of the various weak acids tested was registered for the more lipophilic acids (octanoic acid, followed by benzoic acid) and was minimal for acetic acid. Weak-acid adaptation was found to involve the rapid activation of SPI1 transcription, which is dependent on the presence of the Msn2p transcription factor. Activation of SPI1 transcription upon acetic acid stress also requires Haa1p, whereas this recently described transcription factor has a negligible role in the adaptive response to benzoic acid. The expression of SPI1 was found to play a prominent role in the development of yeast resistance to 1,3-beta-glucanase in benzoic acid-stressed cells, while its involvement in acetic acid-induced resistance to the cell wall-lytic enzyme is slighter. The results are consistent with the notion that Spi1p expression upon weak-acid stress leads to cell wall remodeling, especially for the more lipophilic acids, decreasing cell wall porosity. Decreased cell wall porosity, in turn, reduces access to the plasma membrane, reducing membrane damage, intracellular acidification, and viability loss.

  4. The Role of the Francisella Tularensis Pathogenicity Island in Type VI Secretion, Intracellular Survival, and Modulation of Host Cell Signaling

    PubMed Central

    Bröms, Jeanette E.; Sjöstedt, Anders; Lavander, Moa

    2010-01-01

    Francisella tularensis is a highly virulent gram-negative intracellular bacterium that causes the zoonotic disease tularemia. Essential for its virulence is the ability to multiply within host cells, in particular monocytic cells. The bacterium has developed intricate means to subvert host immune mechanisms and thereby facilitate its intracellular survival by preventing phagolysosomal fusion followed by escape into the cytosol, where it multiplies. Moreover, it targets and manipulates numerous host cell signaling pathways, thereby ameliorating the otherwise bactericidal capacity. Many of the underlying molecular mechanisms still remain unknown but key elements, directly or indirectly responsible for many of the aforementioned mechanisms, rely on the expression of proteins encoded by the Francisella pathogenicity island (FPI), suggested to constitute a type VI secretion system. We here describe the current knowledge regarding the components of the FPI and the roles that have been ascribed to them. PMID:21687753

  5. Identification of DNA sequences from a second pathogenicity island of uropathogenic Escherichia coli CFT073: probes specific for uropathogenic populations.

    PubMed

    Rasko, D A; Phillips, J A; Li, X; Mobley, H L

    2001-10-15

    Uropathogenic Escherichia coli is the leading cause of urinary tract infection and hospital visits in North America. Cystitis and acute pyelonephritis, infection of the bladder and kidney, respectively, are the two most common syndromes encountered in patients with urinary tract infection. We sequenced and annotated 71,684 bases of a previously unidentified pathogenicity-associated island (PAI) from E. coli strain CFT073. This PAI contained 89 open-reading frames encoding a pap operon, iron-regulated genes, mobile genetic elements, and a large proportion of unknown or unidentified open-reading frames. Dot blot analysis with 11 DNA sequences from this PAI demonstrated that 7 sequences were more prevalent among uropathogens: 2 probes were more prevalent among cystitis and pyelonephritis isolates, 2 among pyelonephritis isolates only, and 3 among cystitis isolates only than among fecal isolates. These data suggest that groups of uropathogens have genetic differences that may be responsible for the different clinical outcomes.

  6. Dog overpopulation and burden of exposure to canine distemper virus and other pathogens on Santa Cruz Island, Galapagos.

    PubMed

    Diaz, Nicole M; Mendez, Gabriella S; Grijalva, C Jaime; Walden, Heather S; Cruz, Marilyn; Aragon, Eduardo; Hernandez, Jorge A

    2016-01-01

    Dog overpopulation and diseases are hazards to native island species and humans on the Galapagos. Vaccination and importation of dogs are prohibited on the Galapagos. Risk management of these hazards requires the use of science-based risk assessment and risk communication. The objectives of the study reported here were (i) to estimate the human:dog ratio and (ii) the prevalence of and identify exposure factors associated with positive antibody titers to canine distemper virus (CDV) and other pathogens, as well as infection with intestinal parasites in owned dogs on Santa Cruz Island, Galapagos in September 2014. The observed human:dog ratio was 6.148:1 which extrapolates to 2503 dogs (two times more than a recent dog count conducted by Galapagos Biosecurity Agency in March 2014). The proportion of spayed female dogs (50%) was higher, compared to neutered male dogs (30%) (p=0.04). Prevalence of dogs with positive antibody titers to CDV was 36% (95% CI=26, 46%), to canine parvovirus was 89% (95% CI=82, 95%), and to canine adenovirus was 40% (95% CI=30, 51%). The frequency of seropositive dogs to CDV was lower in urban dogs (26%), compared to rural dogs (53%) (p<0.05). A positive interaction effect between rural residence and spay/neuter status on seropositivity to CDV was observed, which we discuss in this report. Because vaccination is prohibited, the dog population on Santa Cruz is susceptible to an outbreak of CDV (particularly among urban dogs) with potential spill over to marine mammals. Dog's age (1-2 or 3-14 years old, compared to younger dogs), and residence (rural, urban) were associated with positive antibody titers to parvovirus, adenovirus, Ehrlichia spp., or Anaplasma spp., as well as infection with Ancylostoma spp., an intestinal parasite in dogs that can be transmitted to humans, particularly children. These results provide the most comprehensive assessment of dog overpopulation and exposure to CDV and other pathogens on the Galapagos to date.

  7. Functional characterization of the type III secretion ATPase SsaN encoded by Salmonella pathogenicity island 2.

    PubMed

    Yoshida, Yukie; Miki, Tsuyoshi; Ono, Sayaka; Haneda, Takeshi; Ito, Masahiro; Okada, Nobuhiko

    2014-01-01

    A type III secretion system (T3SS) is utilized by a large number of gram-negative bacteria to deliver effectors directly into the cytosol of eukaryotic host cells. One essential component of a T3SS is an ATPase that catalyzes the unfolding of proteins, which is followed by the translocation of effectors through an injectisome. Here we demonstrate a functional role of the ATPase SsaN, a component of Salmonella pathogenicity island 2 T3SS (T3SS-2) in Salmonella enterica serovar Typhimurium. SsaN hydrolyzed ATP in vitro and was essential for T3SS function and Salmonella virulence in vivo. Protein-protein interaction analyses revealed that SsaN interacted with SsaK and SsaQ to form the C ring complex. SsaN and its complex co-localized to the membrane fraction under T3SS-2 inducing conditions. In addition, SsaN bound to Salmonella pathogenicity island 2 (SPI-2) specific chaperones, including SsaE, SseA, SscA, and SscB that facilitated translocator/effector secretion. Using an in vitro chaperone release assay, we demonstrated that SsaN dissociated a chaperone-effector complex, SsaE and SseB, in an ATP-dependent manner. Effector release was dependent on a conserved arginine residue at position 192 of SsaN, and this was essential for its enzymatic activity. These results strongly suggest that the T3SS-2-associated ATPase SsaN contributes to T3SS-2 effector translocation efficiency.

  8. The Salmonella pathogenicity island 2-encoded type III secretion system is essential for the survival of Salmonella enterica serovar Typhimurium in free-living amoebae.

    PubMed

    Bleasdale, Benjamin; Lott, Penelope J; Jagannathan, Aparna; Stevens, Mark P; Birtles, Richard J; Wigley, Paul

    2009-03-01

    Free-living amoebae represent a potential reservoir and predator of Salmonella enterica. Through the use of type III secretion system (T3SS) mutants and analysis of transcription of selected T3SS genes, we demonstrated that the Salmonella pathogenicity island 2 is highly induced during S. enterica serovar Typhimurium infection of Acanthamoeba polyphaga and is essential for survival within amoebae.

  9. Characterization of a novel filarial serine protease inhibitor, Ov-SPI-1, from Onchocerca volvulus, with potential multifunctional roles during development of the parasite.

    PubMed

    Ford, Louise; Guiliano, David B; Oksov, Yelena; Debnath, Asim K; Liu, Jing; Williams, Steven A; Blaxter, Mark L; Lustigman, Sara

    2005-12-01

    A novel filarial serine protease inhibitor (SPI) from the human parasitic nematode Onchocerca volvulus, Ov-SPI-1, was identified through the analysis of a molting third-stage larvae expressed sequence tag dataset. Subsequent analysis of the expressed sequence tag datasets of O. volvulus and other filariae identified four other members of this family. These proteins are related to the low molecular weight SPIs originally isolated from Ascaris suum where they are believed to protect the parasite from host intestinal proteases. The two Ov-spi transcripts are up-regulated in the molting larvae and adult stages of the development of the parasite. Recombinant Ov-SPI-1 is an active inhibitor of serine proteases, specifically elastase, chymotrypsin, and cathepsin G. Immunolocalization of the Ov-SPI proteins demonstrates that the endogenous proteins are localized to the basal layer of the cuticle of third-stage, molting third-stage, and fourth-stage larvae, the body channels and multivesicular bodies of third-stage larvae and the processed material found between the two cuticles during molting. In O. volvulus adult worms the Ov-SPI proteins are localized to the sperm and to eggshells surrounding the developing embryos. RNA interference targeting the Ov-spi genes resulted in the specific knockdown of the transcript levels of both Ov-spi-1 and Ov-spi-2, a loss of native proteins, and a significant reduction in both molting and viability of third-stage larvae. We suggest the Ov-SPI proteins play a vital role in nematode molting by controlling the activity of an endogenous serine protease(s). The localization data in adults also indicate that these inhibitors may be involved in other processes such as embryogenesis and spermatogenesis.

  10. In Silico Analysis of a Novel Plasmid from the Coral Pathogen Vibrio coralliilyticus Reveals Two Potential "Ecological Islands".

    PubMed

    Wachter, Jenny; Hill, Stuart A

    2016-01-01

    As virulence often correlates with the presence of plasmid replicons in several Vibrio spp., this study investigated whether non-chromosomal DNA could be found in the coral pathogen, Vibrio coralliilyticus BAA-450. A circular plasmid, 26,631 bp in size, was identified. DNA sequence analysis indicated that the plasmid contained 30 open reading frames, six tRNA genes, 12 inverted repeats, three direct repeats and presented no continuous sequence identity to other replicons within the database. Consequently, these findings indicate that this is a novel, previously unidentified, plasmid. Two putative "ecological islands" were also identified and are predicted to encode for various factors that would facilitate growth and survival under different ecological conditions. In addition, two open reading frames may encode proteins that contribute to the pathogenicity of the organism. Functional cooperativity is also indicated between several plasmid- and chromosomally-encoded proteins, which, in a single instance, would allow a fully functioning nutrient uptake system to be established. PMID:27681896

  11. The Helicobacter pylori Cag Pathogenicity Island Protein Cag1 is Associated with the Function of T4SS.

    PubMed

    Wang, Xiaochun; Ling, Feng; Wang, Hua; Yu, Min; Zhu, Hong; Chen, Cheng; Qian, Jingyi; Liu, Chang; Zhang, Yuanyuan; Shao, Shihe

    2016-07-01

    The human pathogen Helicobacter pylori is involved in gastric diseases ranging from gastritis to gastric cancer. Virulent strains harboring the cag pathogenicity island (cag PAI) which encode a Type IV Secretion System (T4SS) can induce pro-inflammatory cytokines such as interleukin-8 and deliver their major effector proteins CagA into the gastric cells. While a subset of cag PAI genes have been identified to be the homologues of T4SS genes from Agrobacterium tumefaciens, a majority have unknown functions. We have identified one of such proteins, Cag1, which was predicted to be a non-classically secreted and virulent protein. Our results showed that Cag1 is a membrane-associated protein essential for the induction of multiple cytokine secretions, and cag1-deficient mutant has partial influence on CagA translocation; while the protein itself was not injected into host cells. Our data indicated that Cag1 is located in the bacterial membrane and is associated with the function of T4SS. PMID:26971262

  12. Divergent Roles of Salmonella Pathogenicity Island 2 and Metabolic Traits during Interaction of S. enterica Serovar Typhimurium with Host Cells

    PubMed Central

    Hölzer, Stefanie U.; Hensel, Michael

    2012-01-01

    The molecular mechanisms of virulence of the gastrointestinal pathogen Salmonella enterica are commonly studied using cell culture models of infection. In this work, we performed a direct comparison of the interaction of S. enterica serovar Typhimurium (S. Typhimurium) with the non-polarized epithelial cell line HeLa, the polarized cell lines CaCo2, T84 and MDCK, and macrophage-like RAW264.7 cells. The ability of S. Typhimurium wild-type and previously characterized auxotrophic mutant strains to enter host cells, survive and proliferate within mammalian cells and deploy the Salmonella Pathogenicity Island 2-encoded type III secretion system (SPI2-T3SS) was quantified. We found that the entry of S. Typhimurium into polarized cells was much more efficient than entry into non-polarized cells or phagocytic uptake. While SPI2-T3SS dependent intracellular proliferation was observed in HeLa and RAW cells, the intracellular replication in polarized cells was highly restricted and not affected by defective SPI2-T3SS. The contribution of aromatic amino acid metabolism and purine biosynthesis to intracellular proliferation was distinct in the various cell lines investigated. These observations indicate that the virulence phenotypes of S. Typhimurium are significantly affected by the cell culture model applied. PMID:22427996

  13. Salmonella SPI1 effector SipA persists after entry and cooperates with a SPI2 effector to regulate phagosome maturation and intracellular replication.

    PubMed

    Brawn, Lyndsey C; Hayward, Richard D; Koronakis, Vassilis

    2007-03-15

    Salmonellae employ two type III secretion systems (T3SSs), SPI1 and SPI2, to deliver virulence effectors into mammalian cells. SPI1 effectors, including actin-binding SipA, trigger initial bacterial uptake, whereas SPI2 effectors promote subsequent replication within customized Salmonella-containing vacuoles (SCVs). SCVs sequester actin filaments and subvert microtubule-dependent motors to migrate to the perinuclear region. We demonstrate that SipA delivery continues after Salmonella internalization, with dosage being restricted by host-mediated degradation. SipA is exposed on the cytoplasmic face of the SCV, from where it stimulates bacterial replication in both nonphagocytic cells and macrophages. Although SipA is sufficient to target and redistribute late endosomes, during infection it cooperates with the SPI2 effector SifA to modulate SCV morphology and ensure perinuclear positioning. Our findings define an unexpected additional function for SipA postentry and reveal precise intracellular communication between effectors deployed by distinct T3SSs underlying SCV biogenesis.

  14. Caenorhabditis elegans-based screen identifies Salmonella virulence factors required for conserved host-pathogen interactions.

    PubMed

    Tenor, Jennifer L; McCormick, Beth A; Ausubel, Frederick M; Aballay, Alejandro

    2004-06-01

    A Caenorhabditis elegans-Salmonella enterica host-pathogen model was used to identify both novel and previously known S. enterica virulence factors (HilA, HilD, InvH, SptP, RhuM, Spi4-F, PipA, VsdA, RepC, Sb25, RfaL, GmhA, LeuO, CstA, and RecC), including several related to the type III secretion system (TTSS) encoded in Salmonella pathogenicity island 1 (SPI-1). Mutants corresponding to presumptive novel virulence-related genes exhibited diminished ability to invade epithelial cells and/or to induce polymorphonuclear leukocyte migration in a tissue culture model of mammalian enteropathogenesis. When expressed in C. elegans intestinal cells, the S. enterica TTSS-exported effector protein SptP inhibited a conserved p38 MAPK signaling pathway and suppressed the diminished pathogenicity phenotype of an S. enterica sptP mutant. These results show that C. elegans is an attractive model to study the interaction between Salmonella effector proteins and components of the innate immune response, in part because there is a remarkable overlap between Salmonella virulence factors required for human and nematode pathogenesis.

  15. Proteomic analysis of the sea-island cotton roots infected by wilt pathogen Verticillium dahliae.

    PubMed

    Wang, Fu-Xin; Ma, Yin-Ping; Yang, Chun-Lin; Zhao, Pi-Ming; Yao, Yuan; Jian, Gui-Liang; Luo, Yuan-Ming; Xia, Gui-Xian

    2011-11-01

    Verticillium wilt of cotton is a vascular disease mainly caused by the soil-born filamentous fungus Verticillium dahliae. To study the mechanisms associated with defense responses in wilt-resistant sea-island cotton (Gossypium barbadense) upon V. dahliae infection, a comparative proteomic analysis between infected and mock-inoculated roots of G. barbadense var. Hai 7124 (a cultivar showing resistance against V. dahliae) was performed by 2-DE combined with local EST database-assisted PMF and MS/MS analysis. A total of 51 upregulated and 17 downregulated proteins were identified, and these proteins are mainly involved in defense and stress responses, primary and secondary metabolisms, lipid transport, and cytoskeleton organization. Three novel clues regarding wilt resistance of G. barbadense are gained from this study. First, ethylene signaling was significantly activated in the cotton roots attacked by V. dahliae as shown by the elevated expression of ethylene biosynthesis and signaling components. Second, the Bet v 1 family proteins may play an important role in the defense reaction against Verticillium wilt. Third, wilt resistance may implicate the redirection of carbohydrate flux from glycolysis to pentose phosphate pathway (PPP). To our knowledge, this study is the first root proteomic analysis on cotton wilt resistance and provides important insights for establishing strategies to control this disease.

  16. Evaluation of the Salmonella enterica Serovar Pullorum Pathogenicity Island 2 Mutant as a Candidate Live Attenuated Oral Vaccine.

    PubMed

    Yin, Junlei; Cheng, Zhao; Wang, Xiaochun; Xu, Lijuan; Li, Qiuchun; Geng, Shizhong; Jiao, Xinan

    2015-07-01

    Salmonella enterica serovar Pullorum (S. Pullorum) is a highly adapted pathogen that causes pullorum disease (PD), an important systemic disease of poultry that causes severe economic losses in developing countries. In the interests of developing a safe and immunogenic oral vaccine, the efficacy of a Salmonella pathogenicity island 2 (SPI2)-deleted mutant of S. Pullorum (S06004ΔSPI2) was evaluated in chickens. S06004ΔSPI2 was severely less virulent than the parental wild-type strain S06004 as determined by the 50% lethal dose (LD50) for 3-day-old chickens when injected intramuscularly. Two-day-old chickens immunized with a single oral dose of S06004ΔSPI2 showed no differences in body weight or clinical symptoms compared with those in the negative-control group. S06004ΔSPI2 bacteria were not isolated from livers or spleens of immunized chickens after a short period of time, and specific humoral and cellular immune responses were significantly induced. Immunized chickens were challenged with S. Pullorum strain S06004 and Salmonella enterica serovar Gallinarum (S. Gallinarum) strain SG9 at 10 days postimmunization (dpi), and efficient protection against the challenges was observed. None of the immunized chickens died, the clinical symptoms were slight and temporary following challenge in immunized chickens compared with those in the control group, and these chickens recovered by 3 to 5 dpi. Overall, these results demonstrate that S06004ΔSPI2 can be used as a live attenuated oral vaccine.

  17. Evaluation of the Salmonella enterica Serovar Pullorum Pathogenicity Island 2 Mutant as a Candidate Live Attenuated Oral Vaccine

    PubMed Central

    Yin, Junlei; Cheng, Zhao; Wang, Xiaochun; Xu, Lijuan; Li, Qiuchun; Geng, Shizhong

    2015-01-01

    Salmonella enterica serovar Pullorum (S. Pullorum) is a highly adapted pathogen that causes pullorum disease (PD), an important systemic disease of poultry that causes severe economic losses in developing countries. In the interests of developing a safe and immunogenic oral vaccine, the efficacy of a Salmonella pathogenicity island 2 (SPI2)-deleted mutant of S. Pullorum (S06004ΔSPI2) was evaluated in chickens. S06004ΔSPI2 was severely less virulent than the parental wild-type strain S06004 as determined by the 50% lethal dose (LD50) for 3-day-old chickens when injected intramuscularly. Two-day-old chickens immunized with a single oral dose of S06004ΔSPI2 showed no differences in body weight or clinical symptoms compared with those in the negative-control group. S06004ΔSPI2 bacteria were not isolated from livers or spleens of immunized chickens after a short period of time, and specific humoral and cellular immune responses were significantly induced. Immunized chickens were challenged with S. Pullorum strain S06004 and Salmonella enterica serovar Gallinarum (S. Gallinarum) strain SG9 at 10 days postimmunization (dpi), and efficient protection against the challenges was observed. None of the immunized chickens died, the clinical symptoms were slight and temporary following challenge in immunized chickens compared with those in the control group, and these chickens recovered by 3 to 5 dpi. Overall, these results demonstrate that S06004ΔSPI2 can be used as a live attenuated oral vaccine. PMID:25924763

  18. Genetic structure and distribution of four pathogenicity islands (PAI I(536) to PAI IV(536)) of uropathogenic Escherichia coli strain 536.

    PubMed

    Dobrindt, Ulrich; Blum-Oehler, Gabriele; Nagy, Gabor; Schneider, György; Johann, André; Gottschalk, Gerhard; Hacker, Jörg

    2002-11-01

    For the uropathogenic Escherichia coli strain 536 (O6:K15:H31), the DNA sequences of three pathogenicity islands (PAIs) (PAI I(536) to PAI III(536)) and their flanking regions (about 270 kb) were determined to further characterize the virulence potential of this strain. PAI I(536) to PAI III(536) exhibit features typical of PAIs, such as (i) association with tRNA-encoding genes; (ii) G+C content differing from that of the host genome; (iii) flanking repeat structures; (iv) a mosaic-like structure comprising a multitude of functional, truncated, and nonfunctional putative open reading frames (ORFs) with known or unknown functions; and (v) the presence of many fragments of mobile genetic elements. PAI I(536) to PAI III(536) range between 68 and 102 kb in size. Although these islands contain several ORFs and known virulence determinants described for PAIs of other extraintestinal pathogenic E. coli (ExPEC) isolates, they also consist of as-yet-unidentified ORFs encoding putative virulence factors. The genetic structure of PAI IV(536), which represents the core element of the so-called high-pathogenicity island encoding a siderophore system initially identified in pathogenic yersiniae, was further characterized by sample sequencing. For the first time, multiple PAI sequences (PAI I(536) to PAI IV(536)) in uropathogenic E. coli were studied and their presence in several wild-type E. coli isolates was extensively investigated. The results obtained suggest that these PAIs or at least large fragments thereof are detectable in other pathogenic E. coli isolates. These results support our view that the acquisition of large DNA regions, such as PAIs, by horizontal gene transfer is an important factor for the evolution of bacterial pathogens.

  19. Detection and Molecular Characterization of Potentially Pathogenic Free-living Amoebae from Water Sources in Kish Island, Southern Iran.

    PubMed

    Niyyati, Maryam; Lasgerdi, Zohreh; Lorenzo-Morales, Jacob

    2015-01-01

    Amoebic keratitis, a sight-threatening corneal infection, mainly occurs in contact lens wearers who wash their eyes with tap water. The present research was conducted to identify the occurrence of potentially pathogenic free-living amoebae (FLA) in tap water sources on Kish Island, a tourist region in Iran. Amoebae were detected using a culture-enriched method and by polymerase chain reaction (PCR)/sequencing of the diagnostic fragment 3 region of the 18S rRNA gene of Acanthamoeba. In the case of other free-living amoebae species, PCR/sequencing analysis of the 18S rDNA was conducted. Results of this study showed the presence of Acanthamoeba belonging to T3, T4, T5, and T11 genotypes in tap water sources. Additionally, Vermamoebae vermiformis was detected in three water samples. This is the first report of the Acanthamoeba genotypes T3, T4, T5, and T11 and V. vermiformis species in tap water sources in a tourist region in Iran.

  20. Intracellular survival of Salmonella enterica serovar Typhi in human macrophages is independent of Salmonella pathogenicity island (SPI)-2.

    PubMed

    Forest, Chantal G; Ferraro, Elyse; Sabbagh, Sébastien C; Daigle, France

    2010-12-01

    For successful infection, Salmonella enterica secretes and injects effector proteins into host cells by two distinct type three secretion systems (T3SSs) located on Salmonella pathogenicity islands (SPIs)-1 and -2. The SPI-2 T3SS is involved in intracellular survival of S. enterica serovar Typhimurium and systemic disease. As little is known regarding the function of the SPI-2 T3SS from S. enterica serovar Typhi, the aetiological agent of typhoid fever, we investigated its role for survival in human macrophages. Mutations in the translocon (sseB), basal secretion apparatus (ssaR) and regulator (ssrB) did not result in any reduction in survival under many of the conditions tested. Similar results were obtained with another S. Typhi strain or by using human primary cells. Results were corroborated based on complete deletion of the SPI-2 T3SS. Surprisingly, the data suggest that the SPI-2 T3SS of S. Typhi is not required for survival in human macrophages.

  1. Status of Vi gene, its expression and Salmonella Pathogenicity Island (SPI-7) in Salmonella Typhi in India.

    PubMed

    Maurya, Pushpa; Gulati, Anil K; Nath, Gopal

    2010-07-01

    Salmonella enterica serotype Typhi (S. Typhi) is a causative organism of typhoid fever. A number of Salmonella serovars express a capsular polysaccharide antigen known as Vi, the biosynthetic and export proteins of which are encoded within the viaB locus of Salmonella Pathogenicity Island -7 (SPI-7). SPI-7 is inserted between two partially duplicated copies of tRNA -pheU gene. We have investigated the frequency of viaB operon deletion and loss of SPI-7 due to storage of strains collected during the period 1987-2006 by PCR amplification of fliC (for confirmation of serotype Typhi), tviB (for status of viaB operon) and tRNA -pheU (for absence of SPI-7). All 111 isolates were observed with positive amplification of 495 bp amplicon for fliC. A total of 36 isolates were negative for Vi by agglutination while 39 were negative for viaB operon. Interestingly, 106 isolates were found to have SPI-7. The 5 SPI-7 negative isolates were isolated during recent years. Long-term storage and repeated culture had little or no effect on SPI-7, as none of the 18 isolates recovered from blood before 1997 lacked SPI-7. On the other hand, loss of viaB operon was directly proportional to duration of storage. Thus, it is proposed that stability of Vi gene is dependent on the presence of selection pressure.

  2. Detection and Molecular Characterization of Potentially Pathogenic Free-living Amoebae from Water Sources in Kish Island, Southern Iran

    PubMed Central

    Niyyati, Maryam; Lasgerdi, Zohreh; Lorenzo-Morales, Jacob

    2015-01-01

    Amoebic keratitis, a sight-threatening corneal infection, mainly occurs in contact lens wearers who wash their eyes with tap water. The present research was conducted to identify the occurrence of potentially pathogenic free-living amoebae (FLA) in tap water sources on Kish Island, a tourist region in Iran. Amoebae were detected using a culture-enriched method and by polymerase chain reaction (PCR)/sequencing of the diagnostic fragment 3 region of the 18S rRNA gene of Acanthamoeba. In the case of other free-living amoebae species, PCR/sequencing analysis of the 18S rDNA was conducted. Results of this study showed the presence of Acanthamoeba belonging to T3, T4, T5, and T11 genotypes in tap water sources. Additionally, Vermamoebae vermiformis was detected in three water samples. This is the first report of the Acanthamoeba genotypes T3, T4, T5, and T11 and V. vermiformis species in tap water sources in a tourist region in Iran. PMID:25922581

  3. Salmonella pathogenicity island 2 expression negatively controlled by EIIANtr-SsrB interaction is required for Salmonella virulence.

    PubMed

    Choi, Jeongjoon; Shin, Dongwoo; Yoon, Hyunjin; Kim, Jiae; Lee, Chang-Ro; Kim, Minjeong; Seok, Yeong-Jae; Ryu, Sangryeol

    2010-11-23

    SsrA/SsrB is a primary two-component system that mediates the survival and replication of Salmonella within host cells. When activated, the SsrB response regulator directly promotes the transcription of multiple genes within Salmonella pathogenicity island 2 (SPI-2). As expression of the SsrB protein is promoted by several transcription factors, including SsrB itself, the expression of SPI-2 genes can increase to undesirable levels under activating conditions. Here, we report that Salmonella can avoid the hyperactivation of SPI-2 genes by using ptsN-encoded EIIA(Ntr), a component of the nitrogen-metabolic phosphotransferase system. Under SPI-2-inducing conditions, the levels of SsrB-regulated gene transcription increased abnormally in a ptsN deletion mutant, whereas they decreased in a strain overexpressing EIIA(Ntr). We found that EIIA(Ntr) controls SPI-2 genes by acting on the SsrB protein at the posttranscriptional level. EIIA(Ntr) interacted directly with SsrB, which prevented the SsrB protein from binding to its target promoter. Finally, the Salmonella strain, either lacking the ptsN gene or overexpressing EIIA(Ntr), was unable to replicate within macrophages, and the ptsN deletion mutant was attenuated for virulence in mice. These results indicated that normal SPI-2 gene expression maintained by an EIIA(Ntr)-SsrB interaction is another determinant of Salmonella virulence.

  4. Salmonella pathogenicity island 2-encoded type III secretion system mediates exclusion of NADPH oxidase assembly from the phagosomal membrane.

    PubMed

    Gallois, A; Klein, J R; Allen, L A; Jones, B D; Nauseef, W M

    2001-05-01

    Salmonella typhimurium requires a type III secretion system encoded by pathogenicity island (SPI)-2 to survive and proliferate within macrophages. This survival implies that S. typhimurium avoids or withstands bactericidal events targeted to the microbe-containing vacuole, which include intraphagosomal production of reactive oxygen species (ROS), phagosomal acidification, and delivery of hydrolytic enzymes to the phagosome via fusion with lysosomes. Recent evidence suggests that S. typhimurium alters ROS production by murine macrophages in an SPI-2-dependent manner. To gain insights into the mechanism by which S. typhimurium inhibits intraphagosomal ROS production, we analyzed the subcellular distribution of NADPH oxidase components during infection of human monocyte-derived macrophages by wild-type (WT) or several SPI-2 mutant strains of S. typhimurium. We found that the membrane component of the NADPH oxidase, flavocytochrome b(558), was actively excluded or rapidly removed from the phagosomal membrane of WT-infected monocyte-derived macrophages, thereby preventing assembly of the NADPH oxidase complex and intraphagosomal production of superoxide anion. In contrast, the NADPH oxidase assembled on and generated ROS in phagosomes containing SPI-2 mutant S. typhimurium. Subversion of NADPH oxidase assembly by S. typhimurium was accompanied by increased bacterial replication relative to that of SPI-2 mutant strains, suggesting that the ability of WT S. typhimurium to prevent NADPH oxidase assembly at the phagosomal membrane represents an important virulence factor influencing its intracellular survival.

  5. Survival in amoeba--a major selection pressure on the presence of bacterial copper and zinc resistance determinants? Identification of a "copper pathogenicity island".

    PubMed

    Hao, Xiuli; Lüthje, Freja L; Qin, Yanan; McDevitt, Sylvia Franke; Lutay, Nataliya; Hobman, Jon L; Asiani, Karishma; Soncini, Fernando C; German, Nadezhda; Zhang, Siyu; Zhu, Yong-Guan; Rensing, Christopher

    2015-07-01

    The presence of metal resistance determinants in bacteria usually is attributed to geological or anthropogenic metal contamination in different environments or associated with the use of antimicrobial metals in human healthcare or in agriculture. While this is certainly true, we hypothesize that protozoan predation and macrophage killing are also responsible for selection of copper/zinc resistance genes in bacteria. In this review, we outline evidence supporting this hypothesis, as well as highlight the correlation between metal resistance and pathogenicity in bacteria. In addition, we introduce and characterize the "copper pathogenicity island" identified in Escherichia coli and Salmonella strains isolated from copper- and zinc-fed Danish pigs.

  6. In Vitro Analysis of Predicted DNA-Binding Sites for the Stl Repressor of the Staphylococcus aureus SaPIBov1 Pathogenicity Island

    PubMed Central

    Nyíri, Kinga; Vertessy, Beata G.

    2016-01-01

    The regulation model of the Staphylococcus aureus pathogenicity island SaPIbov1 transfer was recently reported. The repressor protein Stl obstructs the expression of SaPI proteins Str and Xis, latter which is responsible for mobilization initiation. Upon Φ11 phage infection of S. aureus. phage dUTPase activates the SaPI transfer via Stl-dUTPase complex formation. Our aim was to predict the binding sites for the Stl repressor within the S. aureus pathogenicity island DNA sequence. We found that Stl was capable to bind to three 23-mer oligonucleotides, two of those constituting sequence segments in the stl-str, while the other corresponding to sequence segment within the str-xis intergenic region. Within these oligonucleotides, mutational analysis revealed that the predicted binding site for the Stl protein exists as a palindromic segment in both intergenic locations. The palindromes are built as 6-mer repeat sequences involved in Stl binding. The 6-mer repeats are separated by a 5 oligonucleotides long, nonspecific sequence. Future examination of the interaction between Stl and its binding sites in vivo will provide a molecular explanation for the mechanisms of gene repression and gene activation exerted simultaneously by the Stl protein in regulating transfer of the SaPIbov1 pathogenicity island in S. aureus. PMID:27388898

  7. Identification of the Staphylococcus aureus etd pathogenicity island which encodes a novel exfoliative toxin, ETD, and EDIN-B.

    PubMed

    Yamaguchi, Takayuki; Nishifuji, Koji; Sasaki, Megumi; Fudaba, Yasuyuki; Aepfelbacher, Martin; Takata, Takashi; Ohara, Masaru; Komatsuzawa, Hitoshi; Amagai, Masayuki; Sugai, Motoyuki

    2002-10-01

    We identified a novel pathogenicity island in Staphylococcus aureus which contains open reading frames (ORFs) similar to the exfoliative toxin (ET) gene, glutamyl endopeptidase gene, and edin-B gene in tandem and the phage resistance gene, flanked by hsdM, hsdS (restriction and modification system), and IS256. The protein encoded by the ET-like gene showed 40, 59, and 68% amino acid sequence identities with exfoliative toxin A (ETA), exfoliative toxin B (ETB), and Staphylococcus hyicus ETB (ShETB), respectively. When injected into neonatal mice, the recombinant protein derived from the ET-like gene induced exfoliation of the skin with loss of cell-to-cell adhesion in the upper part of the epidermis as observed in histological examinations, just as was found in neonatal mice injected with ETA or ETB. Western blot analysis indicated that the recombinant protein is serologically distinct from ETA and ETB. Therefore, the product encoded by this new ORF is a new ET member produced by S. aureus and is termed ETD. ETD did not induce blisters in 1-day-old chickens. In the skins of mice injected with ETD, cell surface staining of desmoglein 1 (Dsg1), a cadherin type cell-to-cell adhesion molecule in desmosomes, was abolished without affecting that of desmoglein 3 (Dsg3). Furthermore, in vitro incubation of the recombinant extracellular domains of Dsg1 and Dsg3 with the recombinant protein demonstrated that both mouse and human Dsg1, but not Dsg3, were directly cleaved in a dose-dependent manner. These results demonstrate that ETD and ETA induce blister formation by identical pathophysiological mechanisms. Clinical strains positive for edin-B were suggested to be clonally associated, and all edin-B-positive strains tested were positive for etd. Among 18 etd-positive strains, 12 produced ETD extracellularly. Interestingly, these strains are mainly isolated from other sources of infections and not from patients with bullous impetigo or staphylococcal scalded-skin syndrome

  8. The Variable Region of Pneumococcal Pathogenicity Island 1 Is Responsible for Unusually High Virulence of a Serotype 1 Isolate.

    PubMed

    Harvey, Richard M; Trappetti, Claudia; Mahdi, Layla K; Wang, Hui; McAllister, Lauren J; Scalvini, Alexandra; Paton, Adrienne W; Paton, James C

    2016-03-01

    Streptococcus pneumoniae is the leading infectious cause of death in children in the world. However, the mechanisms that drive the progression from asymptomatic colonization to disease are poorly understood. Two virulence-associated genomic accessory regions (ARs) were deleted in a highly virulent serotype 1 clinical isolate (strain 4496) and examined for their contribution to pathogenesis. Deletion of a prophage encoding a platelet-binding protein (PblB) resulted in reduced adherence, biofilm formation, reduced initial infection within the lungs, and a reduction in the number of circulating platelets in infected mice. However, the region's overall contribution to the survival of mice was not significant. In contrast, deletion of the variable region of pneumococcal pathogenicity island 1 (vPPI1) was also responsible for a reduction in adherence and biofilm formation but also reduced survival and invasion of the pleural cavity, blood, and lungs. While the 4496ΔPPI1 strain induced higher expression of the genes encoding interleukin-10 (IL-10) and CD11b in the lungs of challenged mice than the wild-type strain, very few other genes exhibited altered expression. Moreover, while the level of IL-10 protein was increased in the lungs of 4496ΔPPI1 mutant-infected mice compared to strain 4496-infected mice, the levels of gamma interferon (IFN-γ), CXCL10, CCL2, and CCL4 were not different in the two groups. However, the 4496ΔPPI1 mutant was found to be more susceptible than the wild type to phagocytic killing by a macrophage-like cell line. Therefore, our data suggest that vPPI1 may be a major contributing factor to the heightened virulence of certain serotype 1 strains, possibly by influencing resistance to phagocytic killing. PMID:26755156

  9. The effectiveness of preventative mass vaccination regimes against the incidence of highly pathogenic avian influenza on Java Island, Indonesia.

    PubMed

    Bett, B; McLaws, M; Jost, C; Schoonman, L; Unger, F; Poole, J; Lapar, M L; Siregar, E S; Azhar, M; Hidayat, M M; Dunkle, S E; Mariner, J

    2015-04-01

    We conducted an operational research study involving backyard and semicommercial farms on Java Island, Indonesia, between April 2008 and September 2009 to evaluate the effectiveness of two preventive mass vaccination strategies against highly pathogenic avian influenza (HPAI). One regimen used Legok 2003 H5N1 vaccine, while the other used both Legok 2003 H5N1 and HB1 Newcastle disease (ND) vaccine. A total of 16 districts were involved in the study. The sample size was estimated using a formal power calculation technique that assumed a detectable effect of treatment as a 50% reduction in the baseline number of HPAI-compatible outbreaks. Within each district, candidate treatment blocks with village poultry populations ranging from 80 000 to 120 000 were created along subdistrict boundary lines. Subsequently, four of these blocks were randomly selected and assigned one treatment from a list that comprised control, vaccination against HPAI, vaccination against HPAI + ND. Four rounds of vaccination were administered at quarterly intervals beginning in July 2008. A vaccination campaign involved vaccinating 100 000 birds in a treatment block, followed by another 100 000 vaccinations 3 weeks later as a booster dose. Data on disease incidence and vaccination coverage were also collected at quarterly intervals using participatory epidemiological techniques. Compared with the unvaccinated (control) group, the incidence of HPAI-compatible events declined by 32% (P = 0.24) in the HPAI-vaccinated group and by 73% (P = 0.00) in the HPAI- and ND-vaccinated group. The effect of treatment did not vary with time or district. Similarly, an analysis of secondary data from the participatory disease and response (PDSR) database revealed that the incidence of HPAI declined by 12% in the HPAI-vaccinated group and by 24% in the HPAI + ND-vaccinated group. The results suggest that the HPAI + ND vaccination significantly reduced the incidence of HPAI-compatible events in mixed populations of

  10. Salmonella methylglyoxal detoxification by STM3117-encoded lactoylglutathione lyase affects virulence in coordination with Salmonella pathogenicity island 2 and phagosomal acidification.

    PubMed

    Chakraborty, Sangeeta; Chaudhuri, Debalina; Balakrishnan, Arjun; Chakravortty, Dipshikha

    2014-09-01

    Intracellular pathogens such as Salmonella enterica serovar Typhimurium (S. Typhimurium) manipulate their host cells through the interplay of various virulence factors. A multitude of such virulence factors are encoded on the genome of S. Typhimurium and are usually organized in pathogenicity islands. The virulence-associated genomic stretch of STM3117-3120 has structural features of pathogenicity islands and is present exclusively in non-typhoidal serovars of Salmonella. It encodes metabolic enzymes predicted to be involved in methylglyoxal metabolism. STM3117-encoded lactoylglutathione lyase significantly impacts the proliferation of intracellular Salmonella. The deletion mutant of STM3117 (Δlgl) fails to grow in epithelial cells but hyper-replicates in macrophages. This difference in proliferation outcome was the consequence of failure to detoxify methylglyoxal by Δlgl, which was also reflected in the form of oxidative DNA damage and upregulation of kefB in the mutant. Within macrophages, the toxicity of methylglyoxal adducts elicits the potassium efflux channel (KefB) in the mutant which subsequently modulates the acidification of mutant-containing vacuoles (MCVs). The perturbation in the pH of the MCV milieu and bacterial cytosol enhances the Salmonella pathogenicity island 2 translocation in Δlgl, increasing its net growth within macrophages. In epithelial cells, however, the maturation of Δlgl-containing vacuoles were affected as these non-phagocytic cells maintain less acidic vacuoles compared to those in macrophages. Remarkably, ectopic expression of Toll-like receptors 2 and 4 on epithelial cells partially restored the survival of Δlgl. This study identified a novel metabolic enzyme in S. Typhimurium whose activity during intracellular infection within a given host cell type differentially affected the virulence of the bacteria.

  11. Phosphorylation of IRF8 in a pre-associated complex with Spi-1/PU.1 and non-phosphorylated Stat1 is critical for LPS induction of the IL1B gene.

    PubMed

    Unlu, Sebnem; Kumar, Arvind; Waterman, Wayne R; Tsukada, Junichi; Wang, Kent Z Q; Galson, Deborah L; Auron, Philip E

    2007-07-01

    Rapid induction of transcription is known to be mediated by factors which bind DNA following post-translational modification. We report here that non-tyrosine phosphorylated (NTP)-Stat1 is involved in a cooperative interaction with Spi-1/PU.1 and IRF8 to form a pre-associated, poised complex for IL1B gene induction. A double point mutation at a putative STAT binding site, which overlaps this composite Spi-1 x IRF8 site located in the LPS and IL-1 response element (LILRE), inhibited human IL1B LPS-dependent reporter activity to about 10 percent of the control wild type vector. Chromatin immunoprecipitation revealed stimulation-independent constitutive binding of IRF8, Spi-1 and NTP-Stat1 at the LILRE, while binding of C/EBP beta was activated at an adjacent C/EBP beta site after LPS stimulation. In contrast to Stat1, IRF8 was tyrosine phosphorylated following LPS treatment. Supporting the involvement of NTP-Stat1, LPS-induced IL1B reporter activity in monocytes was enhanced by ectopic expression of NTP-Stat1 Y701F. In contrast, co-expression of a Y211F IRF8 mutein functioned as a dominant-negative inhibitor of LPS-induced IL1B reporter activity. In vitro DNA binding using extracts from LPS-treated monocytes confirmed that the LILRE enhancer constitutively binds a trimolecular complex containing IRF8, Spi-1 and NTP-Stat1. Binding studies using in vitro-expressed proteins revealed that NTP-Stat1 enhanced the binding of Spi-1 and IRF8 to the LILRE. Co-expression of TRAF6, an LPS surrogate, with Spi-1 and IRF8 enhanced IL1B reporter activity in HEK293R cells, which was dramatically reduced when Y211F IRF8 was co-expressed. These results suggest that the rapid transcriptional induction of an important inflammatory gene is dependent upon constitutive cooperative binding of a Spi-1 x IRF8 x NTP-Stat1 complex to the LILRE, which primes the gene for immediate induction following IRF8 phosphorylation. Phosphorylation of chromatin pre-associated factors like IRF8 may be an

  12. Pathogenicity island cag, vacA and IS605 genotypes in Mexican strains of Helicobacter pylori associated with peptic ulcers

    PubMed Central

    2011-01-01

    Background Helicobacter pylori is associated with chronic gastritis, peptic ulcers, and gastric cancer. Two major virulence factors of H. pylori have been described: the pathogenicity island cag (cag PAI) and the vacuolating cytotoxin gene (vacA). Virtually all strains have a copy of vacA, but its genotype varies. The cag PAI is a region of 32 genes in which the insertion of IS605 elements in its middle region has been associated with partial or total deletions of it that have generated strains with varying virulence. Accordingly, the aim of this work was to determine the cag PAI integrity, vacA genotype and IS605 status in groups of isolates from Mexican patients with non-peptic ulcers (NPU), non-bleeding peptic ulcers (NBPU), and bleeding peptic ulcers (BPU). Methods The cag PAI integrity was performed by detection of eleven targeted genes along this locus using dot blot hybridization and PCR assays. The vacA allelic, cag PAI genotype 1 and IS605 status were determined by PCR analysis. Results Groups of 16-17 isolates (n = 50) from two patients with NPU, NBPU, and BPU, respectively, were studied. 90% (45/50) of the isolates harbored a complete cag PAI. Three BPU isolates lacked the cag PAI, and two of the NBPU had an incomplete cag PAI: the first isolate was negative for three of its genes, including deletion of the cagA gene, whereas the second did not have the cagM gene. Most of the strains (76%) had the vacA s1b/m1 genotype; meanwhile the IS605 was not present within the cag PAI of any strain but was detected elsewhere in the genome of 8% (4/50). Conclusion The patients had highly virulent strains since the most of them possessed a complete cag PAI and had a vacA s1b/m1 genotype. All the isolates presented the cag PAI without any IS605 insertion (genotype 1). Combined vacA genotypes showed that 1 NPU, 2 NBPU, and 1 BPU patients (66.6%) had a mixed infection; coexistence of H. pylori strains with different cag PAI status was observed in 1 NBPU and 2 BPU (50

  13. The High-Pathogenicity Island of Yersinia enterocolitica Ye8081 Undergoes Low-Frequency Deletion but Not Precise Excision, Suggesting Recent Stabilization in the Genome

    PubMed Central

    Bach, Sandrine; Buchrieser, Carmen; Prentice, Michael; Guiyoule, Annie; Msadek, Tarek; Carniel, Elisabeth

    1999-01-01

    Highly pathogenic strains of Yersinia pestis, Y. pseudotuberculosis, and Y. enterocolitica are characterized by the possession of a pathogenicity island designated the high-pathogenicity island (HPI). This 35- to 45-kb island carries an iron uptake system named the yersiniabactin locus. While the HPIs of Y. pestis and Y. pseudotuberculosis are subject to high-frequency spontaneous deletion from the chromosome, we were initially unable to obtain HPI-deleted Y. enterocolitica 1B isolates. In the present study, using a positive selection strategy, we identified three HPI-deleted mutants of Y. enterocolitica strain Ye8081. In these three independent clones, the chromosomal deletion was not limited to the HPI but encompassed a larger DNA fragment of approximately 140 kb. Loss of this fragment, which occurred at a frequency of approximately 5 × 10−7, resulted in the disappearance of several phenotypic traits, such as growth in a minimal medium, hydrolysis of o-nitrophenyl-β-d-thiogalactopyranoside, Tween esterase activity, and motility, and in a decreased virulence for mice. However, no precise excision of the Ye8081 HPI was observed. To gain more insight into the molecular basis for this phenomenon, the putative machinery of HPI excision in Y. enterocolitica was analyzed and compared to that in Y. pseudotuberculosis. We show that the probable reasons for failure of precise excision of the HPI of Y. enterocolitica Ye8081 are (i) the interruption of the P4-like integrase gene located close to its right-hand boundary by a premature stop codon and (ii) lack of conservation of 17-bp att-like sequences at both extremities of the HPI. These mutations may represent a process of HPI stabilization in the species Y. enterocolitica. PMID:10496882

  14. Epstein-Barr virus nuclear antigen 3C binds to BATF/IRF4 or SPI1/IRF4 composite sites and recruits Sin3A to repress CDKN2A.

    PubMed

    Jiang, Sizun; Willox, Bradford; Zhou, Hufeng; Holthaus, Amy M; Wang, Anqi; Shi, Tommy T; Maruo, Seiji; Kharchenko, Peter V; Johannsen, Eric C; Kieff, Elliott; Zhao, Bo

    2014-01-01

    Epstein-Barr virus nuclear antigen 3C (EBNA3C) repression of CDKN2A p14(ARF) and p16(INK4A) is essential for immortal human B-lymphoblastoid cell line (LCL) growth. EBNA3C ChIP-sequencing identified >13,000 EBNA3C sites in LCL DNA. Most EBNA3C sites were associated with active transcription; 64% were strong H3K4me1- and H3K27ac-marked enhancers and 16% were active promoters marked by H3K4me3 and H3K9ac. Using ENCODE LCL transcription factor ChIP-sequencing data, EBNA3C sites coincided (±250 bp) with RUNX3 (64%), BATF (55%), ATF2 (51%), IRF4 (41%), MEF2A (35%), PAX5 (34%), SPI1 (29%), BCL11a (28%), SP1 (26%), TCF12 (23%), NF-κB (23%), POU2F2 (23%), and RBPJ (16%). EBNA3C sites separated into five distinct clusters: (i) Sin3A, (ii) EBNA2/RBPJ, (iii) SPI1, and (iv) strong or (v) weak BATF/IRF4. EBNA3C signals were positively affected by RUNX3, BATF/IRF4 (AICE) and SPI1/IRF4 (EICE) cooccupancy. Gene set enrichment analyses correlated EBNA3C/Sin3A promoter sites with transcription down-regulation (P < 1.6 × 10(-4)). EBNA3C signals were strongest at BATF/IRF4 and SPI1/IRF4 composite sites. EBNA3C bound strongly to the p14(ARF) promoter through SPI1/IRF4/BATF/RUNX3, establishing RBPJ-, Sin3A-, and REST-mediated repression. EBNA3C immune precipitated with Sin3A and conditional EBNA3C inactivation significantly decreased Sin3A binding at the p14(ARF) promoter (P < 0.05). These data support a model in which EBNA3C binds strongly to BATF/IRF4/SPI1/RUNX3 sites to enhance transcription and recruits RBPJ/Sin3A- and REST/NRSF-repressive complexes to repress p14(ARF) and p16(INK4A) expression. PMID:24344258

  15. Full Genome Sequence Analysis of Two Isolates Reveals a Novel Xanthomonas Species Close to the Sugarcane Pathogen Xanthomonas albilineans

    PubMed Central

    Pieretti, Isabelle; Cociancich, Stéphane; Bolot, Stéphanie; Carrère, Sébastien; Morisset, Alexandre; Rott, Philippe; Royer, Monique

    2015-01-01

    Xanthomonas albilineans is the bacterium responsible for leaf scald, a lethal disease of sugarcane. Within the Xanthomonas genus, X. albilineans exhibits distinctive genomic characteristics including the presence of significant genome erosion, a non-ribosomal peptide synthesis (NRPS) locus involved in albicidin biosynthesis, and a type 3 secretion system (T3SS) of the Salmonella pathogenicity island-1 (SPI-1) family. We sequenced two X. albilineans-like strains isolated from unusual environments, i.e., from dew droplets on sugarcane leaves and from the wild grass Paspalum dilatatum, and compared these genomes sequences with those of two strains of X. albilineans and three of Xanthomonas sacchari. Average nucleotide identity (ANI) and multi-locus sequence analysis (MLSA) showed that both X. albilineans-like strains belong to a new species close to X. albilineans that we have named “Xanthomonas pseudalbilineans”. X. albilineans and “X. pseudalbilineans” share many genomic features including (i) the lack of genes encoding a hypersensitive response and pathogenicity type 3 secretion system (Hrp-T3SS), and (ii) genome erosion that probably occurred in a common progenitor of both species. Our comparative analyses also revealed specific genomic features that may help X. albilineans interact with sugarcane, e.g., a PglA endoglucanase, three TonB-dependent transporters and a glycogen metabolism gene cluster. Other specific genomic features found in the “X. pseudalbilineans” genome may contribute to its fitness and specific ecological niche. PMID:26213974

  16. Identification of a Gene within a Pathogenicity Island of Enterotoxigenic Escherichia coli H10407 Required for Maximal Secretion of the Heat-Labile Enterotoxin

    PubMed Central

    Fleckenstein, James M.; Lindler, Luther E.; Elsinghorst, Eric A.; Dale, James B.

    2000-01-01

    Studies of the pathogenesis of enterotoxigenic Escherichia coli (ETEC) have largely centered on extrachromosomal determinants of virulence, in particular the plasmid-encoded heat-labile (LT) and heat-stable enterotoxins and the colonization factor antigens. ETEC causes illnesses that range from mild diarrhea to severe cholera-like disease. These differences in disease severity are not readily accounted for by our current understanding of ETEC pathogenesis. Here we demonstrate that Tia, a putative adhesin of ETEC H10407, is encoded on a large chromosomal element of approximately 46 kb that shares multiple features with previously described E. coli pathogenicity islands. Further analysis of the region downstream from tia revealed the presence of several candidate open reading frames (ORFs) in the same transcriptional orientation as tia. The putative proteins encoded by these ORFs bear multiple motifs associated with bacterial secretion apparatuses. An in-frame deletion in one candidate gene identified here as leoA (labile enterotoxin output) resulted in marked diminution of secretion of the LT enterotoxin and lack of fluid accumulation in a rabbit ileal loop model of infection. Although previous studies have suggested that E. coli lacks the capacity to secrete LT, our studies show that maximal release of LT from the periplasm of H10407 is dependent on one or more elements encoded on a pathogenicity island. PMID:10768971

  17. GI-type T4SS-mediated horizontal transfer of the 89K pathogenicity island in epidemic Streptococcus suis serotype 2.

    PubMed

    Li, Ming; Shen, Xiaodong; Yan, Jinghua; Han, Huiming; Zheng, Beiwen; Liu, Di; Cheng, Hao; Zhao, Yan; Rao, Xiancai; Wang, Changjun; Tang, Jiaqi; Hu, Fuquan; Gao, George F

    2011-03-01

    Pathogenicity islands (PAIs), a distinct type of genomic island (GI), play important roles in the rapid adaptation and increased virulence of pathogens. 89K is a newly identified PAI in epidemic Streptococcus suis isolates that are related to the two recent large-scale outbreaks of human infection in China. However, its mechanism of evolution and contribution to the epidemic spread of S. suis 2 remain unknown. In this study, the potential for mobilization of 89K was evaluated, and its putative transfer mechanism was investigated. We report that 89K can spontaneously excise to form an extrachromosomal circular product. The precise excision is mediated by an 89K-borne integrase through site-specific recombination, with help from an excisionase. The 89K excision intermediate acts as a substrate for lateral transfer to non-89K S. suis 2 recipients, where it reintegrates site-specifically into the target site. The conjugal transfer of 89K occurred via a GI type IV secretion system (T4SS) encoded in 89K, at a frequency of 10(-6) transconjugants per donor. This is the first demonstration of horizontal transfer of a Gram-positive PAI mediated by a GI-type T4SS. We propose that these genetic events are important in the emergence, pathogenesis and persistence of epidemic S. suis 2 strains.

  18. Presence of pathogenicity island related and plasmid encoded virulence genes in cytolethal distending toxin producing Escherichia coli isolates from diarrheal cases

    PubMed Central

    Oloomi, Mana; Javadi, Maryam; Bouzari, Saeid

    2015-01-01

    Context: Mobile genetic elements such as plasmids, bacteriophages, insertion elements, and genomic islands play a critical role in virulence of bacterial pathogens. These elements transfer horizontally and could play an important role in the evolution and virulence of many pathogens. A broad spectrum of gram-negative bacterial species has been shown to produce a cytolethal distending toxin (CDT). On the other hand, Shiga toxin producing Escherichia coli are the one carry virulence genes such as stx 1 and stx 2 (Shiga toxin) and these genes can be acquired by horizontal gene transfer. Aim: The aim of this study was to investigate the presence of other virulence associated genes among CDT producing E. coli strains. Materials and Methods: Thirty CDT positive strains isolated from patients with diarrhea were characterized. Thereafter, the association with virulent genetic elements in known pathogenicity islands (PAIs) was assessed by polymerase chain reaction. Results: In this study, it was shown that the most CDT producing E. coli isolates express Shiga toxin. Moreover, the presence of prophages framing cdt genes (like P2 phage) was also identified in each cdt-type genomic group. Flanked regions of cdt-I, cdt-IV, and cdt-V-type was similar to plasmid sequences while cdt-II and cdt-III-type regions similarity with hypothetical protein (orf3) was observed. Conclusion: The occurrence of each cdt-type groups with specific virulence genes and PAI genetic elements is indicative of horizontal gene transfer by these mobile genetic elements, which could lead to diversity among the isolates. PMID:26539367

  19. Pathogenicity islands in Shiga toxin-producing Escherichia coli O26, O103, and O111 isolates from humans and animals.

    PubMed

    Ju, Wenting; Rump, Lydia; Toro, Magaly; Shen, Jinling; Cao, Guojie; Zhao, Shaohua; Meng, Jianghong

    2014-05-01

    Non-O157 Shiga toxin-producing Escherichia coli (STEC) are increasingly recognized as foodborne pathogens worldwide. Serogroups O26, O111, and O103 cause most known outbreaks related to non-O157 STEC. Pathogenicity islands (PAIs) play a major role in the evolution of STEC pathogenicity. To determine the distribution of PAIs often associated with highly virulent STECs (OI-122, OI-43/48, OI-57, and high pathogenicity islands) among STEC O26, O103, and O111, a collection of STEC O26 (n=45), O103 (n=29), and O111 (n=52) from humans and animals were included in this study. Pulsed-field gel electrophoresis (PFGE) with XbaI digestion was used to characterize the clonal relationship of the strains. In addition, a polymerase chain reaction-restriction fragment length polymorphism assay was used to determine eae subtypes. Additional virulence genes on PAIs were identified using specific PCR assays, including OI-122: pagC, sen, efa-1, efa-2, and nleB; OI-43/48: terC, ureC, iha, and aidA-1; OI-57: nleG2-3, nleG5-2, and nleG6-2; and HPI: fyuA and irp2. A PFGE dendrogram demonstrated that instead of clustering together with strains from the same O type (O111:H8), the O111:H11 (n=14) strains clustered together with strains of the same H type (O26:H11, n=45). In addition, O26:H11 and O111:H11 strains carried eae subtype β, whereas O111:H8 strains had eae γ2/θ. The O26:H11 and O111:H11 stains contained an incomplete OI-122 lacking pagC and a complete HPI. However, a complete OI-122 but no HPI was found in the O111:H8 strains. Additionally, aidA-1 of OI-43/48 and nleG6-2 of OI-57 were significantly associated with O26:H11 and O111:H11 strains but were almost missing in O111:H8 strains (p<0.001). This study demonstrated that H11 (O111:H11 and O26:H11) strains were closely related and may have come from the same ancestor.

  20. Role of Nod1 in mucosal dendritic cells during Salmonella pathogenicity island 1-independent Salmonella enterica serovar Typhimurium infection.

    PubMed

    Le Bourhis, Lionel; Magalhaes, Joao Gamelas; Selvanantham, Thirumahal; Travassos, Leonardo H; Geddes, Kaoru; Fritz, Jörg H; Viala, Jérôme; Tedin, Karsten; Girardin, Stephen E; Philpott, Dana J

    2009-10-01

    Recent advances in immunology have highlighted the critical function of pattern-recognition molecules (PRMs) in generating the innate immune response to effectively target pathogens. Nod1 and Nod2 are intracellular PRMs that detect peptidoglycan motifs from the cell walls of bacteria once they gain access to the cytosol. Salmonella enterica serovar Typhimurium is an enteric intracellular pathogen that causes a severe disease in the mouse model. This pathogen resides within vacuoles inside the cell, but the question of whether cytosolic PRMs such as Nod1 and Nod2 could have an impact on the course of S. Typhimurium infection in vivo has not been addressed. Here, we show that deficiency in the PRM Nod1, but not Nod2, resulted in increased susceptibility toward a mutant strain of S. Typhimurium that targets directly lamina propria dendritic cells (DCs) for its entry into the host. Using this bacterium and bone marrow chimeras, we uncovered a surprising role for Nod1 in myeloid cells controlling bacterial infection at the level of the intestinal lamina propria. Indeed, DCs deficient for Nod1 exhibited impaired clearance of the bacteria, both in vitro and in vivo, leading to increased organ colonization and decreased host survival after oral infection. Taken together, these findings demonstrate a key role for Nod1 in the host response to an enteric bacterial pathogen through the modulation of intestinal lamina propria DCs.

  1. Comparative analysis of the Hrp pathogenicity island of Rubus- and Spiraeoideae-infecting Erwinia amylovora strains identifies the IT region as a remnant of an integrative conjugative element.

    PubMed

    Mann, Rachel A; Blom, Jochen; Bühlmann, Andreas; Plummer, Kim M; Beer, Steven V; Luck, Joanne E; Goesmann, Alexander; Frey, Jürg E; Rodoni, Brendan C; Duffy, Brion; Smits, Theo H M

    2012-08-01

    The Hrp pathogenicity island (hrpPAI) of Erwinia amylovora not only encodes a type III secretion system (T3SS) and other genes required for pathogenesis on host plants, but also includes the so-called island transfer (IT) region, a region that originates from an integrative conjugative element (ICE). Comparative genomic analysis of the IT regions of two Spiraeoideae- and three Rubus-infecting strains revealed that the regions in Spiraeoideae-infecting strains were syntenic and highly conserved in length and genetic information, but that the IT regions of the Rubus-infecting strains varied in gene content and length, showing a mosaic structure. None of the ICEs in E. amylovora strains were complete, as conserved ICE genes and the left border were missing, probably due to reductive genome evolution. Comparison of the hrpPAI region of E. amylovora strains to syntenic regions from other Erwinia spp. indicates that the hrpPAI and the IT regions are the result of several insertion and deletion events that have occurred within the ICE. It also suggests that the T3SS was present in a common ancestor of the pathoadapted Erwinia spp. and that insertion and deletion events in the IT region occurred during speciation.

  2. Bactericidal effect of polyethyleneimine capped ZnO nanoparticles on multiple antibiotic resistant bacteria harboring genes of high-pathogenicity island.

    PubMed

    Chakraborti, Soumyananda; Mandal, Amit Kumar; Sarwar, Shamila; Singh, Prashantee; Chakraborty, Ranadhir; Chakrabarti, Pinak

    2014-09-01

    Zinc oxide nanoparticles (ZnO-NP) were synthesized by alcoholic route using zinc acetate as the precursor material and lithium hydroxide as hydrolyzing agent. Further ZnO-PEI NP (derivative of ZnO-NP) was made in aqueous medium using the capping agent polyethyleneimine (PEI). The nanoparticles were characterized by XRD measurements, TEM and other techniques; the weight % of coating shell in the polymer-capped particles was determined by TGA. ZnO-PEI NP is more soluble in water than the uncapped ZnO-NP, and forms a colloidal suspension in water. PEI-capped ZnO-NP exhibited better antibacterial activity when compared with that of uncapped ZnO-NP against a range of multiple-antibiotic-resistant (MAR) Gram-negative bacterial strains harboring genes of high-pathogenicity island. ZnO-NP effectively killed these microorganisms by generating reactive oxygen species (ROS) and damaging bacterial membrane. ZnO-PEI NP at LD50 dose in combination with tetracycline showed synergistic effect to inhibit tetracycline-resistant Escherichia coli MREC33 growth by 80%. These results open up a new vista in therapeutics to use antibiotics (which have otherwise been rendered useless against MAR bacteria) in combination with minimized dosage of nanoparticles for the more effective control of MAR pathogenic bacteria.

  3. Diarrhea and colitis in mice require the Salmonella pathogenicity island 2-encoded secretion function but not SifA or Spv effectors.

    PubMed

    Fierer, Joshua; Okamoto, Sharon; Banerjee, Ananya; Guiney, Donald G

    2012-10-01

    We investigated the roles of Salmonella pathogenicity island 2 (SPI-2) and two SPI-2 effectors in Salmonella colitis and diarrhea in genetically resistant BALB/c.D2(Slc11a1) congenic mice with the wild-type Nramp1 locus. Wild-type Salmonella enterica serovar Typhimurium 14028s caused a pan-colitis, and the infected mice developed frank diarrhea with a doubling of the fecal water content. An ssaV mutant caused only a 26% increase in fecal water content, without producing the pathological changes of colitis, and it did not cause weight loss over a 1-week period of observation. However, two SPI-2 effector mutants, the spvB and sifA mutants, and a double spvB sifA mutant caused diarrhea and colitis, even though the sifA mutant was sensitive to killing by bone marrow-derived macrophages from BALB/c.D2 mice and was severely impaired in extraintestinal growth but not in growth in the cecum. These results demonstrate that systemic S. enterica infection and diarrhea/colitis are distinct pathogenic processes and that only the former requires spvB and sifA.

  4. Expression and secretion of Salmonella pathogenicity island-2 virulence genes in response to acidification exhibit differential requirements of a functional type III secretion apparatus and SsaL.

    PubMed

    Coombes, Brian K; Brown, Nat F; Valdez, Yanet; Brumell, John H; Finlay, B Brett

    2004-11-26

    Salmonella pathogenicity island (SPI)-2 is pivotal to the intracellular survival of Salmonella and for virulence in mammals. SPI-2 encodes virulence factors (called effectors) that are translocated into the host cell, a type III secretion apparatus and a two-component regulatory system that regulates intracellular expression of SPI-2. Salmonella SPI-2 secretion activity appears to be induced in response to acidification of the vacuole in which it replicates. Here we show that the expression of the SPI-2 proteins, SseB and SseD (filament and pore forming components of the secretion apparatus, respectively) in response to acidification requires an intact secretion system and SsaL, a Salmonella homologue of SepL, a regulator required for type III-dependent secretion of translocators but not effectors in attaching and effacing gastrointestinal pathogens. We show that the expression of SPI-2-encoded effectors is acid-regulated but can be uncoupled from the expression of filament and translocon components, thus showing a differential requirement of SsaL for expression. The secretion and translocation of SPI-2-encoded effectors requires SsaL, but SsaL is dispensable for the secretion of SPI-2 effectors encoded in other pathogenicity loci, suggesting a secretion regulation function for SsaL. Further, we demonstrate that the differential expression of adjacent genes within the sseA operon (sseD and sseE) occurs at the transcriptional level. These data indicate that a Salmonella SPI-2 activation state is achieved by an acidregulated response that requires SsaL. These data also suggest the existence of a previously unrecognized regulatory element within SPI-2 for the "effector operon" region downstream of sseD that might demarcate the expression of translocators and effectors.

  5. The hrp pathogenicity island of Pseudomonas syringae pv. tomato DC3000 is induced by plant phenolic acids.

    PubMed

    Lee, Jun Seung; Ryu, Hye Ryun; Cha, Ji Young; Baik, Hyung Suk

    2015-10-01

    Plants produce a wide array of antimicrobial compounds, such as phenolic compounds, to combat microbial pathogens. The hrp PAI is one of the major virulence factors in the plant pathogen, Pseudomonas syringae. A major role of hrp PAI is to disable the plant defense system during bacterial invasion. We examined the influence of phenolic compounds on hrp PAI gene expression at low and high concentrations. There was approximately 2.5 times more hrpA and hrpZ mRNA in PtoDC3000 that was grown in minimal media (MM) supplemented with 10 -M of ortho-coumaric acid than in PtoDC3000 grown in MM alone. On the other hand, a significantly lower amount of hrpA mRNA was observed in bacteria grown in MM supplemented with a high concentration of phenolic compounds. To determine the regulation pathway for hrp PAI gene expression, we performed qRTPCR using gacS, gacA, and hrpS deletion mutants. PMID:26428924

  6. Genetic analysis of environmental strains of the plant pathogen Phytophthora capsici reveals heterogeneous repertoire of effectors and possible effector evolution via genomic island.

    PubMed

    Iribarren, María Josefina; Pascuan, Cecilia; Soto, Gabriela; Ayub, Nicolás Daniel

    2015-11-01

    Phytophthora capsici is a virulent oomycete pathogen of many vegetable crops. Recently, it has been demonstrated that the recognition of the RXLR effector AVR3a1 of P. capsici (PcAVR3a1) triggers a hypersensitive response and plays a critical role in mediating non-host resistance. Here, we analyzed the occurrence of PcAVR3a1 in 57 isolates of P. capsici derived from globe squash, eggplant, tomato and bell pepper cocultivated in a small geographical area. The occurrence of PcAVR3a1 in environmental strains of P. capsici was confirmed by PCR in only 21 of these pathogen isolates. To understand the presence-absence pattern of PcAVR3a1 in environmental strains, the flanking region of this gene was sequenced. PcAVR3a1 was found within a genetic element that we named PcAVR3a1-GI (PcAVR3a1 genomic island). PcAVR3a1-GI was flanked by a 22-bp direct repeat, which is related to its site-specific recombination site. In addition to the PcAVR3a1 gene, PcAVR3a1-GI also encoded a phage integrase probably associated with the excision and integration of this mobile element. Exposure to plant induced the presence of an episomal circular intermediate of PcAVR3a1-GI, indicating that this mobile element is functional. Collectively, these findings provide evidence of PcAVR3a1 evolution via mobile elements in environmental strains of Phytophthora.

  7. Genes encoding putative effector proteins of the type III secretion system of Salmonella pathogenicity island 2 are required for bacterial virulence and proliferation in macrophages.

    PubMed

    Hensel, M; Shea, J E; Waterman, S R; Mundy, R; Nikolaus, T; Banks, G; Vazquez-Torres, A; Gleeson, C; Fang, F C; Holden, D W

    1998-10-01

    The type III secretion system of Salmonella pathogenicity island 2 (SPI-2) is required for systemic infection of this pathogen in mice. Cloning and sequencing of a central region of SPI-2 revealed the presence of genes encoding putative chaperones and effector proteins of the secretion system. The predicted products of the sseB, sseC and sseD genes display weak but significant similarity to amino acid sequences of EspA, EspD and EspB, which are secreted by the type III secretion system encoded by the locus of enterocyte effacement of enteropathogenic Escherichia coli. The transcriptional activity of an sseA::luc fusion gene was shown to be dependent on ssrA, which is required for the expression of genes encoding components of the secretion system apparatus. Strains carrying nonpolar mutations in sseA, sseB or sseC were severely attenuated in virulence, strains carrying mutations in sseF or sseG were weakly attenuated, and a strain with a mutation in sseE had no detectable virulence defect. These phenotypes were reflected in the ability of mutant strains to grow within a variety of macrophage cell types: strains carrying mutations in sseA, sseB or sseC failed to accumulate, whereas the growth rates of strains carrying mutations in sseE, sseF or sseG were only modestly reduced. These data suggest that, in vivo, one of the functions of the SPI-2 secretion system is to enable intracellular bacterial proliferation.

  8. Genetic analysis of environmental strains of the plant pathogen Phytophthora capsici reveals heterogeneous repertoire of effectors and possible effector evolution via genomic island.

    PubMed

    Iribarren, María Josefina; Pascuan, Cecilia; Soto, Gabriela; Ayub, Nicolás Daniel

    2015-11-01

    Phytophthora capsici is a virulent oomycete pathogen of many vegetable crops. Recently, it has been demonstrated that the recognition of the RXLR effector AVR3a1 of P. capsici (PcAVR3a1) triggers a hypersensitive response and plays a critical role in mediating non-host resistance. Here, we analyzed the occurrence of PcAVR3a1 in 57 isolates of P. capsici derived from globe squash, eggplant, tomato and bell pepper cocultivated in a small geographical area. The occurrence of PcAVR3a1 in environmental strains of P. capsici was confirmed by PCR in only 21 of these pathogen isolates. To understand the presence-absence pattern of PcAVR3a1 in environmental strains, the flanking region of this gene was sequenced. PcAVR3a1 was found within a genetic element that we named PcAVR3a1-GI (PcAVR3a1 genomic island). PcAVR3a1-GI was flanked by a 22-bp direct repeat, which is related to its site-specific recombination site. In addition to the PcAVR3a1 gene, PcAVR3a1-GI also encoded a phage integrase probably associated with the excision and integration of this mobile element. Exposure to plant induced the presence of an episomal circular intermediate of PcAVR3a1-GI, indicating that this mobile element is functional. Collectively, these findings provide evidence of PcAVR3a1 evolution via mobile elements in environmental strains of Phytophthora. PMID:26443834

  9. Self-renewal of leukemia stem cells in Friend virus-induced erythroleukemia requires proviral insertional activation of Spi1 and hedgehog signaling but not mutation of p53.

    PubMed

    Hegde, Shailaja; Hankey, Pamela; Paulson, Robert F

    2012-02-01

    Friend virus induces erythroleukemia through a characteristic two-stage progression. The prevailing model proposes that during the initial, polyclonal stage of disease most of the infected cells terminally differentiate, resulting in acute erythrocytosis. In the late stage of disease, a clonal leukemia develops through the acquisition of new mutations--proviral insertional activation of Spi1/Pu.1 and mutation of p53. Previous work from our laboratory demonstrated that Friend virus activates the bone morphogenic protein 4 (BMP4)-dependent stress erythropoiesis pathway, which leads to the rapid expansion of stress erythroid progenitors, which are the targets for Friend virus in the spleen. We recently showed that stress erythroid progenitors have intrinsic self-renewal ability and therefore could function as leukemia stem cells (LSCs) when infected with Friend virus. Here, we show that the two stages of Friend virus-induced disease are caused by infection of distinct stress progenitor populations in the spleen. The development of leukemia relies on the ability of the virus to hijack the intrinsic self-renewal capability of stress erythroid progenitors leading to the generation of LSCs. Two signals are required for the self-renewal of Friend virus LSCs proviral insertional activation of Spi1/Pu.1 and Hedgehog-dependent signaling. Surprisingly, mutation of p53 is not observed in LSCs. These data establish a new model for Friend virus-induced erythroleukemia and demonstrate the utility of Friend virus as a model system to study LSC self-renewal.

  10. Locally advanced breast cancers are more likely to present as Interval Cancers: results from the I-SPY 1 TRIAL (CALGB 150007/150012, ACRIN 6657, InterSPORE Trial).

    PubMed

    Lin, Cheryl; Buxton, Meredith Becker; Moore, Dan; Krontiras, Helen; Carey, Lisa; DeMichele, Angela; Montgomery, Leslie; Tripathy, Debasish; Lehman, Constance; Liu, Minetta; Olapade, Olufunmilayo; Yau, Christina; Berry, Donald; Esserman, Laura J

    2012-04-01

    Interval cancers (ICs), defined as cancers detected between regular screening mammograms, have been shown to be of higher grade, larger size, and associated with lower survival, compared with screen-detected cancers (SDCs) and comprise 17% of cancers from population-based screening programs. We sought to determine the frequency of ICs in a study of locally advanced breast cancers, the I-SPY 1 TRIAL. Screening was defined as having a mammogram with 2 years, and the proportion of ICs at 1 and 2 years was calculated for screened patients. Differences in clinical characteristics for ICs versus SDCs and screened versus non-screened cancers were assessed. For the 219 evaluable women, mean tumor size was 6.8 cm. Overall, 80% of women were over 40 and eligible for screening; however, only 31% were getting screened. Among women screened, 85% were ICs, with 68% diagnosed within 1 year of a previously normal mammogram. ICs were of higher grade (49% vs. 10%) than SDCs. Among non-screened women, 28% (43/152) were younger than the recommended screening age of 40. Of the entire cohort, 12% of cancers were mammographically occult (MO); the frequency of MO cancers did not differ between screened (11%) and non-screened (15%). ICs were common in the I-SPY 1 TRIAL suggesting the potential need for new approaches beyond traditional screening to reduce mortality in women who present with larger palpable cancers.

  11. The iron-sensing fur regulator controls expression timing and levels of salmonella pathogenicity island 2 genes in the course of environmental acidification.

    PubMed

    Choi, Eunna; Kim, Hyunkeun; Lee, Hwiseop; Nam, Daesil; Choi, Jeongjoon; Shin, Dongwoo

    2014-06-01

    In order to survive inside macrophages, Salmonella produces a series of proteins encoded by genes within Salmonella pathogenicity island 2 (SPI-2). In the present study, we report that Fur, a central regulator of iron utilization, negatively controls the expression of SPI-2 genes. Time course analysis of SPI-2 expression after the entry of Salmonella into macrophages revealed that SPI-2 genes are induced earlier and at higher levels in the absence of the Fur regulator. It was hypothesized that Fur repressed the SPI-2 expression that was activated during acidification of the phagosome. Indeed, as pH was lowered from pH 7.0 to pH 5.5, the lack of Fur enabled SPI-2 gene expression to be induced at higher pH and to be expressed at higher levels. Fur controlled SPI-2 genes via repression of the SsrB response regulator, a primary activator of SPI-2 expression. Fur repressed ssrB expression both inside macrophages and under acidic conditions, which we ascribe to the direct binding of Fur to the ssrB promoter. Our study suggests that Salmonella could employ iron inside the phagosome to precisely control the timing and levels of SPI-2 expression inside macrophages.

  12. The Helicobacter pylori cag Pathogenicity Island Protein CagN Is a Bacterial Membrane-Associated Protein That Is Processed at Its C Terminus

    PubMed Central

    Bourzac, Kevin M.; Satkamp, Laura A.; Guillemin, Karen

    2006-01-01

    Helicobacter pylori infects nearly half the world's population and is associated with a spectrum of gastric maladies. Infections with cytotoxin-associated gene pathogenicity island (cag PAI)-containing strains are associated with an increased risk for gastric cancer. The cag PAI contains genes encoding a type IV secretion system (T4SS) and a delivered effector, CagA, that becomes tyrosine phosphorylated upon delivery into host cells and initiates changes in cell signaling. Although some cag PAI genes have been shown to be required for CagA delivery, a subset of which are homologues of T4SS genes from Agrobacterium tumefaciens, the majority have no known function or homologues. We have performed a detailed investigation of one such cag PAI protein, CagN, which is encoded by the gene HP0538. Our results show that CagN is not delivered into host cells and instead is associated with the bacterial membrane. We demonstrate that CagN is cleaved at its C terminus by a mechanism that is independent of other cag PAI proteins. Finally, we show that a ΔcagN mutant is not impaired in its ability to deliver CagA to gastric epithelial cells and initiate cell elongation. PMID:16622188

  13. The Helicobacter pylori cag pathogenicity island protein CagN is a bacterial membrane-associated protein that is processed at its C terminus.

    PubMed

    Bourzac, Kevin M; Satkamp, Laura A; Guillemin, Karen

    2006-05-01

    Helicobacter pylori infects nearly half the world's population and is associated with a spectrum of gastric maladies. Infections with cytotoxin-associated gene pathogenicity island (cag PAI)-containing strains are associated with an increased risk for gastric cancer. The cag PAI contains genes encoding a type IV secretion system (T4SS) and a delivered effector, CagA, that becomes tyrosine phosphorylated upon delivery into host cells and initiates changes in cell signaling. Although some cag PAI genes have been shown to be required for CagA delivery, a subset of which are homologues of T4SS genes from Agrobacterium tumefaciens, the majority have no known function or homologues. We have performed a detailed investigation of one such cag PAI protein, CagN, which is encoded by the gene HP0538. Our results show that CagN is not delivered into host cells and instead is associated with the bacterial membrane. We demonstrate that CagN is cleaved at its C terminus by a mechanism that is independent of other cag PAI proteins. Finally, we show that a delta cagN mutant is not impaired in its ability to deliver CagA to gastric epithelial cells and initiate cell elongation. PMID:16622188

  14. Attenuated Salmonella Typhimurium Lacking the Pathogenicity Island-2 Type 3 Secretion System Grow to High Bacterial Numbers inside Phagocytes in Mice

    PubMed Central

    Grant, Andrew J.; Morgan, Fiona J. E.; McKinley, Trevelyan J.; Foster, Gemma L.; Maskell, Duncan J.; Mastroeni, Pietro

    2012-01-01

    Intracellular replication within specialized vacuoles and cell-to-cell spread in the tissue are essential for the virulence of Salmonella enterica. By observing infection dynamics at the single-cell level in vivo, we have discovered that the Salmonella pathogenicity island 2 (SPI-2) type 3 secretory system (T3SS) is dispensable for growth to high intracellular densities. This challenges the concept that intracellular replication absolutely requires proteins delivered by SPI-2 T3SS, which has been derived largely by inference from in vitro cell experiments and from unrefined measurement of net growth in mouse organs. Furthermore, we infer from our data that the SPI-2 T3SS mediates exit from infected cells, with consequent formation of new infection foci resulting in bacterial spread in the tissues. This suggests a new role for SPI-2 in vivo as a mediator of bacterial spread in the body. In addition, we demonstrate that very similar net growth rates of attenuated salmonellae in organs can be derived from very different underlying intracellular growth dynamics. PMID:23236281

  15. Quinolones Induce Partial or Total Loss of Pathogenicity Islands in Uropathogenic Escherichia coli by SOS-Dependent or -Independent Pathways, Respectively

    PubMed Central

    Soto, S. M.; Jimenez de Anta, M. T.; Vila, J.

    2006-01-01

    Escherichia coli is the most common microorganism causing urinary tract infections. Quinolone-resistant E. coli strains have fewer virulence factors than quinolone-susceptible strains. Several urovirulence genes are located in pathogenicity islands (PAIs). We investigated the capacity of quinolones to induce loss of virulence factors such as hemolysin, cytotoxic necrotizing factor 1, P fimbriae, and autotransporter Sat included in PAIs in three uropathogenic E. coli strains. In a multistep selection, all strains lost hemolytic capacity at between 1 and 4 passages when they were incubated with subinhibitory concentrations of ciprofloxacin, showing a partial or total loss of the PAI containing the hly (hemolysin) and cnf-1 (cytotoxic necrotizing factor 1) genes. RecA− mutants were obtained from the two E. coli strains with partial or total loss of the PAI. The inactivation of the RecA protein affected only the partial loss of the PAI induced by quinolones. No spontaneous loss of PAIs was observed on incubation in the absence of quinolones in either the wild-type or mutant E. coli strains. Quinolones induce partial or total loss of PAIs in vitro in uropathogenic E. coli by SOS-dependent or -independent pathways, respectively. PMID:16436722

  16. SseBCD Proteins Are Secreted by the Type III Secretion System of Salmonella Pathogenicity Island 2 and Function as a Translocon

    PubMed Central

    Nikolaus, Thomas; Deiwick, Jörg; Rappl, Catherine; Freeman, Jeremy A.; Schröder, Werner; Miller, Samuel I.; Hensel, Michael

    2001-01-01

    The type III secretion system encoded by Salmonella pathogenicity island 2 (SPI2) is required for systemic infections and intracellular accumulation of Salmonella enterica. This system is induced by intracellular Salmonella and subsequently transfers effector proteins into the host cell. Growth conditions either inducing expression of the type III secretion system or the secretion of substrate proteins were defined. Here we report the identification of a set of substrate proteins consisting of SseB, SseC, and SseD that are secreted by the SPI2 system in vitro. Secretion was observed if bacterial cells were exposed to acidic pH after growth in minimal medium with limitation of Mg2+ or phosphate. SseB, -C, and -D were isolated in a fraction detached from the bacterial cell surface by mechanical shearing, indicating that these proteins are predominantly assembled into complexes on the bacterial cell surface. The three proteins were required for the translocation of SPI2 effector proteins SspH1 and SspH2 into infected host cells. Thus, SseB, SseC, and SseD function as the translocon for effector proteins by intracellular Salmonella. PMID:11567004

  17. Systematic mutagenesis of the Helicobacter pylori cag pathogenicity island: essential genes for CagA translocation in host cells and induction of interleukin-8.

    PubMed

    Fischer, W; Püls, J; Buhrdorf, R; Gebert, B; Odenbreit, S; Haas, R

    2001-12-01

    Helicobacter pylori (Hp) carries a type IV secretion system encoded by the cag pathogenicity island (cag-PAI), which is used to: (i) translocate the bacterial effector protein CagA into different types of eukaryotic cells; and (ii) induce the synthesis and secretion of chemokines, such as interleukin-8 (IL-8). The cag-PAI in Hp 26695 consists of 27 putative genes, six of which were identified as homologues to the basic type IV secretion system represented by the Agrobacterium tumefaciens virB operon. To define the role and contribution of each of the 27 genes, we applied a precise deletion/insertion mutagenesis procedure to knock out each individual gene without causing polar effects on the expression of downstream genes. Seventeen out of 27 genes were found to be absolutely essential for translocation of CagA into host cells and 14 out of 27 for the ability of Hp fully to induce transcription of IL-8. The products of hp0524 (virD4 homologue), hp0526 and hp0540 are absolutely essential for the translocation of CagA, but not for the induction of IL-8. In contrast, the products of hp0520, hp0521, hp0534, hp0535, hp0536 and hp0543 are not necessary for either translocation of CagA or for IL-8 induction. Our data argue against a translocated IL-8-inducing effector protein encoded by the cag-PAI. We isolated a variant of Hp 26695, which spontaneously switched off its capacity for IL-8 induction and translocation of CagA, but retained the complete cag-PAI. We identified a point mutation in gene hp0532, causing a premature translational stop in the corresponding polypeptide chain, providing a putative explanation for the defect in the type IV secretion system of the spontaneous mutant. PMID:11886563

  18. The Type VI Secretion System Encoded in Salmonella Pathogenicity Island 19 Is Required for Salmonella enterica Serotype Gallinarum Survival within Infected Macrophages

    PubMed Central

    Blondel, Carlos J.; Jiménez, Juan C.; Leiva, Lorenzo E.; Álvarez, Sergio A.; Pinto, Bernardo I.; Contreras, Francisca; Pezoa, David; Santiviago, Carlos A.

    2013-01-01

    Salmonella enterica serotype Gallinarum is the causative agent of fowl typhoid, a disease characterized by high morbidity and mortality that causes major economic losses in poultry production. We have reported that S. Gallinarum harbors a type VI secretion system (T6SS) encoded in Salmonella pathogenicity island 19 (SPI-19) that is required for efficient colonization of chicks. In the present study, we aimed to characterize the SPI-19 T6SS functionality and to investigate the mechanisms behind the phenotypes previously observed in vivo. Expression analyses revealed that SPI-19 T6SS core components are expressed and produced under in vitro bacterial growth conditions. However, secretion of the structural/secreted components Hcp1, Hcp2, and VgrG to the culture medium could not be determined, suggesting that additional signals are required for T6SS-dependent secretion of these proteins. In vitro bacterial competition assays failed to demonstrate a role for SPI-19 T6SS in interbacterial killing. In contrast, cell culture experiments with murine and avian macrophages (RAW264.7 and HD11, respectively) revealed production of a green fluorescent protein-tagged version of VgrG soon after Salmonella uptake. Furthermore, infection of RAW264.7 and HD11 macrophages with deletion mutants of SPI-19 or strains with genes encoding specific T6SS core components (clpV and vgrG) revealed that SPI-19 T6SS contributes to S. Gallinarum survival within macrophages at 20 h postuptake. SPI-19 T6SS function was not linked to Salmonella-induced cytotoxicity or cell death of infected macrophages, as has been described for other T6SS. Our data indicate that SPI-19 T6SS corresponds to a novel tool used by Salmonella to survive within host cells. PMID:23357385

  19. The response regulator SsrB activates expression of diverse Salmonella pathogenicity island 2 promoters and counters silencing by the nucleoid-associated protein H-NS.

    PubMed

    Walthers, Don; Carroll, Ronan K; Navarre, William Wiley; Libby, Stephen J; Fang, Ferric C; Kenney, Linda J

    2007-07-01

    The two-component system SsrA-SsrB activates expression of a type III secretion system required for replication in macrophages and systemic infection in mice. Here we characterize the SsrB-dependent regulation of genes within Salmonella pathogenicity island 2 (SPI-2). Primer extension and DNase I footprinting identified multiple SsrB-regulated promoters within SPI-2 located upstream of ssaB, sseA, ssaG and ssaM. We previously demonstrated that ssrA and ssrB transcription is uncoupled. Overexpression of SsrB in the absence of its cognate kinase, SsrA, is sufficient to activate SPI-2 transcription. Because SsrB requires phosphorylation to relieve inhibitory contacts that occlude its DNA-binding domain, additional components must phosphorylate SsrB. SPI-2 promoters examined in single copy were highly SsrB-dependent, activated during growth in macrophages and induced by acidic pH. The nucleoid structuring protein H-NS represses horizontally acquired genes; we confirmed that H-NS is a negative regulator of SPI-2 gene expression. In the absence of H-NS, the requirement for SsrB in activating SPI-2 genes is substantially reduced, suggesting a role for SsrB in countering H-NS silencing. SsrB activates transcription of multiple operons within SPI-2 by binding to degenerate DNA targets at diversely organized promoters. SsrB appears to possess dual activities to promote SPI-2 gene expression: activation of transcription and relief of H-NS-mediated repression.

  20. The type VI secretion system encoded in Salmonella pathogenicity island 19 is required for Salmonella enterica serotype Gallinarum survival within infected macrophages.

    PubMed

    Blondel, Carlos J; Jiménez, Juan C; Leiva, Lorenzo E; Alvarez, Sergio A; Pinto, Bernardo I; Contreras, Francisca; Pezoa, David; Santiviago, Carlos A; Contreras, Inés

    2013-04-01

    Salmonella enterica serotype Gallinarum is the causative agent of fowl typhoid, a disease characterized by high morbidity and mortality that causes major economic losses in poultry production. We have reported that S. Gallinarum harbors a type VI secretion system (T6SS) encoded in Salmonella pathogenicity island 19 (SPI-19) that is required for efficient colonization of chicks. In the present study, we aimed to characterize the SPI-19 T6SS functionality and to investigate the mechanisms behind the phenotypes previously observed in vivo. Expression analyses revealed that SPI-19 T6SS core components are expressed and produced under in vitro bacterial growth conditions. However, secretion of the structural/secreted components Hcp1, Hcp2, and VgrG to the culture medium could not be determined, suggesting that additional signals are required for T6SS-dependent secretion of these proteins. In vitro bacterial competition assays failed to demonstrate a role for SPI-19 T6SS in interbacterial killing. In contrast, cell culture experiments with murine and avian macrophages (RAW264.7 and HD11, respectively) revealed production of a green fluorescent protein-tagged version of VgrG soon after Salmonella uptake. Furthermore, infection of RAW264.7 and HD11 macrophages with deletion mutants of SPI-19 or strains with genes encoding specific T6SS core components (clpV and vgrG) revealed that SPI-19 T6SS contributes to S. Gallinarum survival within macrophages at 20 h postuptake. SPI-19 T6SS function was not linked to Salmonella-induced cytotoxicity or cell death of infected macrophages, as has been described for other T6SS. Our data indicate that SPI-19 T6SS corresponds to a novel tool used by Salmonella to survive within host cells.

  1. The response regulator SsrB activates transcription and binds to a region overlapping OmpR binding sites at Salmonella pathogenicity island 2.

    PubMed

    Feng, Xiuhong; Walthers, Don; Oropeza, Ricardo; Kenney, Linda J

    2004-11-01

    OmpR activates expression of the two-component regulatory system located on Salmonella pathogenicity island 2 (SPI-2) that controls the expression of a type III secretion system, as well as many other genes required for systemic infection in mice. Measurements of SsrA and SsrB protein levels under different growth conditions indicate that expression of these two components is uncoupled, i.e. SsrB is produced in the absence of ssrA and vice versa. This result was suggested from our previous studies, in which two promoters at ssrA/B were identified. The isolated C-terminus of SsrB binds to DNA and protects regions upstream of ssrA, ssrB and srfH from DNase I digestion. Furthermore, the C-terminus of SsrB alone is capable of activating transcription in the absence of the N-terminus. Results from beta-galactosidase assays indicate that the N-terminal phosphorylation domain inhibits the C-terminal effector domain. A previous study from our laboratory reported that ssrA-lacZ and ssrB-lacZ transcriptional fusions were substantially reduced in an ssrB null strain. Results from DNase I protection assays provide direct evidence that SsrB binds at ssrA and ssrB, although the binding sites lie within the transcribed regions. Additional regulators clearly affect gene expression at this important locus, and here we provide evidence that SlyA, a transcription factor that contributes to Salmonella virulence, also affects ssrA/B gene expression.

  2. Chemotherapy response and recurrence-free survival in neoadjuvant breast cancer depends on biomarker profiles: results from the I-SPY 1 TRIAL (CALGB 150007/150012; ACRIN 6657).

    PubMed

    Esserman, Laura J; Berry, Donald A; Cheang, Maggie C U; Yau, Christina; Perou, Charles M; Carey, Lisa; DeMichele, Angela; Gray, Joe W; Conway-Dorsey, Kathleen; Lenburg, Marc E; Buxton, Meredith B; Davis, Sarah E; van't Veer, Laura J; Hudis, Clifford; Chin, Koei; Wolf, Denise; Krontiras, Helen; Montgomery, Leslie; Tripathy, Debu; Lehman, Constance; Liu, Minetta C; Olopade, Olufunmilayo I; Rugo, Hope S; Carpenter, John T; Livasy, Chad; Dressler, Lynn; Chhieng, David; Singh, Baljit; Mies, Carolyn; Rabban, Joseph; Chen, Yunni-Yi; Giri, Dilip; Au, Alfred; Hylton, Nola

    2012-04-01

    Neoadjuvant chemotherapy for breast cancer allows individual tumor response to be assessed depending on molecular subtype, and to judge the impact of response to therapy on recurrence-free survival (RFS). The multicenter I-SPY 1 TRIAL evaluated patients with ≥ 3 cm tumors by using early imaging and molecular signatures, with outcomes of pathologic complete response (pCR) and RFS. The current analysis was performed using data from patients who had molecular profiles and did not receive trastuzumab. The various molecular classifiers tested were highly correlated. Categorization of breast cancer by molecular signatures enhanced the ability of pCR to predict improvement in RFS compared to the population as a whole. In multivariate analysis, the molecular signatures that added to the ability of HR and HER2 receptors, clinical stage, and pCR in predicting RFS included 70-gene signature, wound healing signature, p53 mutation signature, and PAM50 risk of recurrence. The low risk signatures were associated with significantly better prognosis, and also identified additional patients with a good prognosis within the no pCR group, primarily in the hormone receptor positive, HER-2 negative subgroup. The I-SPY 1 population is enriched for tumors with a poor prognosis but is still heterogeneous in terms of rates of pCR and RFS. The ability of pCR to predict RFS is better by subset than it is for the whole group. Molecular markers improve prediction of RFS by identifying additional patients with excellent prognosis within the no pCR group.

  3. Virulence Gene Regulation by l-Arabinose in Salmonella enterica

    PubMed Central

    López-Garrido, Javier; Puerta-Fernández, Elena; Cota, Ignacio; Casadesús, Josep

    2015-01-01

    Invasion of the intestinal epithelium is a critical step in Salmonella enterica infection and requires functions encoded in the gene cluster known as Salmonella Pathogenicity Island 1 (SPI-1). Expression of SPI-1 genes is repressed by l-arabinose, and not by other pentoses. Transport of l-arabinose is necessary to repress SPI-1; however, repression is independent of l-arabinose metabolism and of the l-arabinose-responsive regulator AraC. SPI-1 repression by l-arabinose is exerted at a single target, HilD, and the mechanism appears to be post-translational. As a consequence of SPI-1 repression, l-arabinose reduces translocation of SPI-1 effectors to epithelial cells and decreases Salmonella invasion in vitro. These observations reveal a hitherto unknown role of l-arabinose in gene expression control and raise the possibility that Salmonella may use L-arabinose as an environmental signal. PMID:25991823

  4. Virulence Gene Regulation by L-Arabinose in Salmonella enterica.

    PubMed

    López-Garrido, Javier; Puerta-Fernández, Elena; Cota, Ignacio; Casadesús, Josep

    2015-07-01

    Invasion of the intestinal epithelium is a critical step in Salmonella enterica infection and requires functions encoded in the gene cluster known as Salmonella Pathogenicity Island 1 (SPI-1). Expression of SPI-1 genes is repressed by L-arabinose, and not by other pentoses. Transport of L-arabinose is necessary to repress SPI-1; however, repression is independent of L-arabinose metabolism and of the L-arabinose-responsive regulator AraC. SPI-1 repression by L-arabinose is exerted at a single target, HilD, and the mechanism appears to be post-translational. As a consequence of SPI-1 repression, l-arabinose reduces translocation of SPI-1 effectors to epithelial cells and decreases Salmonella invasion in vitro. These observations reveal a hitherto unknown role of L-arabinose in gene expression control and raise the possibility that Salmonella may use L-arabinose as an environmental signal.

  5. Identification and Sequence Analysis of a 27-Kilobase Chromosomal Fragment Containing a Salmonella Pathogenicity Island Located at 92 Minutes on the Chromosome Map of Salmonella enterica Serovar Typhimurium LT2

    PubMed Central

    Wong, Kwong-Kwok; McClelland, Michael; Stillwell, Lisa C.; Sisk, Ellen C.; Thurston, Sarah J.; Saffer, Jeffrey D.

    1998-01-01

    Using a genomic approach, we have identified a new Salmonella pathogenicity island, SPI-4, which is the fourth Salmonella pathogenicity island to be identified. SPI-4 was located at 92 min on the chromosome map and was flanked by the ssb and soxSR loci. The DNA sequence covering the entire SPI-4 and both boundaries was determined. The size of SPI-4 was about 25 kb and it contains 18 putative open reading frames (ORFs). Three of these ORFs encode proteins that have significant homology with proteins involved in toxin secretion. Another five ORFs encode proteins that have significant homology with hypothetical proteins from Synechocystis sp. strain PCC6803 or Acinetobacter calcoaceticus. The rest of the ORFs encode novel proteins, one of which has five membrane-spanning domains. SPI-4 is likely to carry a type I secretion system involved in toxin secretion. Furthermore, a previously identified locus (ims98), which is required for intramacrophage survival, was also mapped within the SPI-4 region. These findings suggested that SPI-4 is needed for intramacrophage survival. PMID:9632606

  6. Identification of Tenrec ecaudatus, a Wild Mammal Introduced to Mayotte Island, as a Reservoir of the Newly Identified Human Pathogenic Leptospira mayottensis.

    PubMed

    Lagadec, Erwan; Gomard, Yann; Le Minter, Gildas; Cordonin, Colette; Cardinale, Eric; Ramasindrazana, Beza; Dietrich, Muriel; Goodman, Steven M; Tortosa, Pablo; Dellagi, Koussay

    2016-08-01

    Leptospirosis is a bacterial zoonosis of major concern on tropical islands. Human populations on western Indian Ocean islands are strongly affected by the disease although each archipelago shows contrasting epidemiology. For instance, Mayotte, part of the Comoros Archipelago, differs from the other neighbouring islands by a high diversity of Leptospira species infecting humans that includes Leptospira mayottensis, a species thought to be unique to this island. Using bacterial culture, molecular detection and typing, the present study explored the wild and domestic local mammalian fauna for renal carriage of leptospires and addressed the genetic relationships of the infecting strains with local isolates obtained from acute human cases and with Leptospira strains hosted by mammal species endemic to nearby Madagascar. Tenrec (Tenrec ecaudatus, Family Tenrecidae), a terrestrial mammal introduced from Madagascar, is identified as a reservoir of L. mayottensis. All isolated L. mayottensis sequence types form a monophyletic clade that includes Leptospira strains infecting humans and tenrecs on Mayotte, as well as two other Malagasy endemic tenrecid species of the genus Microgale. The lower diversity of L. mayottensis in tenrecs from Mayotte, compared to that occurring in Madagascar, suggests that L. mayottensis has indeed a Malagasy origin. This study also showed that introduced rats (Rattus rattus) and dogs are probably the main reservoirs of Leptospira borgpetersenii and Leptospira kirschneri, both bacteria being prevalent in local clinical cases. Data emphasize the epidemiological link between the two neighbouring islands and the role of introduced small mammals in shaping the local epidemiology of leptospirosis.

  7. Identification of Tenrec ecaudatus, a Wild Mammal Introduced to Mayotte Island, as a Reservoir of the Newly Identified Human Pathogenic Leptospira mayottensis

    PubMed Central

    Lagadec, Erwan; Gomard, Yann; Le Minter, Gildas; Cordonin, Colette; Cardinale, Eric; Ramasindrazana, Beza; Dietrich, Muriel; Goodman, Steven M; Tortosa, Pablo; Dellagi, Koussay

    2016-01-01

    Leptospirosis is a bacterial zoonosis of major concern on tropical islands. Human populations on western Indian Ocean islands are strongly affected by the disease although each archipelago shows contrasting epidemiology. For instance, Mayotte, part of the Comoros Archipelago, differs from the other neighbouring islands by a high diversity of Leptospira species infecting humans that includes Leptospira mayottensis, a species thought to be unique to this island. Using bacterial culture, molecular detection and typing, the present study explored the wild and domestic local mammalian fauna for renal carriage of leptospires and addressed the genetic relationships of the infecting strains with local isolates obtained from acute human cases and with Leptospira strains hosted by mammal species endemic to nearby Madagascar. Tenrec (Tenrec ecaudatus, Family Tenrecidae), a terrestrial mammal introduced from Madagascar, is identified as a reservoir of L. mayottensis. All isolated L. mayottensis sequence types form a monophyletic clade that includes Leptospira strains infecting humans and tenrecs on Mayotte, as well as two other Malagasy endemic tenrecid species of the genus Microgale. The lower diversity of L. mayottensis in tenrecs from Mayotte, compared to that occurring in Madagascar, suggests that L. mayottensis has indeed a Malagasy origin. This study also showed that introduced rats (Rattus rattus) and dogs are probably the main reservoirs of Leptospira borgpetersenii and Leptospira kirschneri, both bacteria being prevalent in local clinical cases. Data emphasize the epidemiological link between the two neighbouring islands and the role of introduced small mammals in shaping the local epidemiology of leptospirosis. PMID:27574792

  8. Identification of Tenrec ecaudatus, a Wild Mammal Introduced to Mayotte Island, as a Reservoir of the Newly Identified Human Pathogenic Leptospira mayottensis.

    PubMed

    Lagadec, Erwan; Gomard, Yann; Le Minter, Gildas; Cordonin, Colette; Cardinale, Eric; Ramasindrazana, Beza; Dietrich, Muriel; Goodman, Steven M; Tortosa, Pablo; Dellagi, Koussay

    2016-08-01

    Leptospirosis is a bacterial zoonosis of major concern on tropical islands. Human populations on western Indian Ocean islands are strongly affected by the disease although each archipelago shows contrasting epidemiology. For instance, Mayotte, part of the Comoros Archipelago, differs from the other neighbouring islands by a high diversity of Leptospira species infecting humans that includes Leptospira mayottensis, a species thought to be unique to this island. Using bacterial culture, molecular detection and typing, the present study explored the wild and domestic local mammalian fauna for renal carriage of leptospires and addressed the genetic relationships of the infecting strains with local isolates obtained from acute human cases and with Leptospira strains hosted by mammal species endemic to nearby Madagascar. Tenrec (Tenrec ecaudatus, Family Tenrecidae), a terrestrial mammal introduced from Madagascar, is identified as a reservoir of L. mayottensis. All isolated L. mayottensis sequence types form a monophyletic clade that includes Leptospira strains infecting humans and tenrecs on Mayotte, as well as two other Malagasy endemic tenrecid species of the genus Microgale. The lower diversity of L. mayottensis in tenrecs from Mayotte, compared to that occurring in Madagascar, suggests that L. mayottensis has indeed a Malagasy origin. This study also showed that introduced rats (Rattus rattus) and dogs are probably the main reservoirs of Leptospira borgpetersenii and Leptospira kirschneri, both bacteria being prevalent in local clinical cases. Data emphasize the epidemiological link between the two neighbouring islands and the role of introduced small mammals in shaping the local epidemiology of leptospirosis. PMID:27574792

  9. How Salmonella became a pathogen.

    PubMed

    Groisman, E A; Ochman, H

    1997-09-01

    In many pathogens, virulence can be conferred by a single region of the genome. In contrast, the facultative intracellular lifestyle of Salmonella demands a large number of genes distributed around the chromosome. The evolution of Salmonella has been marked by the acquisition of several 'pathogenicity islands', each contributing to the unique virulence properties of this microorganism.

  10. Another look at the mechanism involving trimeric dUTPases in Staphylococcus aureus pathogenicity island induction involves novel players in the party

    PubMed Central

    Maiques, Elisa; Quiles-Puchalt, Nuria; Donderis, Jorge; Ciges-Tomas, J. Rafael; Alite, Christian; Bowring, Janine Z.; Humphrey, Suzanne; Penadés, José R.; Marina, Alberto

    2016-01-01

    We have recently proposed that the trimeric staphylococcal phage encoded dUTPases (Duts) are signaling molecules that act analogously to eukaryotic G-proteins, using dUTP as a second messenger. To perform this regulatory role, the Duts require their characteristic extra motif VI, present in all the staphylococcal phage coded trimeric Duts, as well as the strongly conserved Dut motif V. Recently, however, an alternative model involving Duts in the transfer of the staphylococcal islands (SaPIs) has been suggested, questioning the implication of motifs V and VI. Here, using state-of the-art techniques, we have revisited the proposed models. Our results confirm that the mechanism by which the Duts derepress the SaPI cycle depends on dUTP and involves both motifs V and VI, as we have previously proposed. Surprisingly, the conserved Dut motif IV is also implicated in SaPI derepression. However, and in agreement with the proposed alternative model, the dUTP inhibits rather than inducing the process, as we had initially proposed. In summary, our results clarify, validate and establish the mechanism by which the Duts perform regulatory functions. PMID:27112567

  11. The Francisella tularensis migR, trmE, and cphA Genes Contribute to F. tularensis Pathogenicity Island Gene Regulation and Intracellular Growth by Modulation of the Stress Alarmone ppGpp

    PubMed Central

    Faron, Matthew; Fletcher, Joshua R.; Rasmussen, Jed A.; Long, Matthew E.; Allen, Lee-Ann H.

    2013-01-01

    The Francisella tularensis pathogenicity island (FPI) encodes many proteins that are required for virulence. Expression of these genes depends upon the FevR (PigR) regulator and its interactions with the MglA/SspA and RNA polymerase transcriptional complex. Experiments to identify how transcription of the FPI genes is activated have led to identification of mutations within the migR, trmE, and cphA genes that decrease FPI expression. Recent data demonstrated that the small alarmone ppGpp, produced by RelA and SpoT, is important for stabilizing MglA/SspA and FevR (PigR) interactions in Francisella. Production of ppGpp is commonly known to be activated by cellular and nutritional stress in bacteria, which indicates that cellular and nutritional stresses act as important signals for FPI activation. In this work, we demonstrate that mutations in migR, trmE, or cphA significantly reduce ppGpp accumulation. The reduction in ppGpp levels was similar for each of the mutants and correlated with a corresponding reduction in iglA reporter expression. In addition, we observed that there were differences in the ability of each of these mutants to replicate within various mammalian cells, indicating that the migR, trmE, and cphA genes are likely parts of different cellular stress response pathways in Francisella. These results also indicate that different nutritional and cellular stresses exist in different mammalian cells. This work provides new information to help understand how Francisella regulates its virulence genes in response to host cell environments, and it contributes to our growing knowledge of this highly successful bacterial pathogen. PMID:23716606

  12. The Francisella tularensis migR, trmE, and cphA genes contribute to F. tularensis pathogenicity island gene regulation and intracellular growth by modulation of the stress alarmone ppGpp.

    PubMed

    Faron, Matthew; Fletcher, Joshua R; Rasmussen, Jed A; Long, Matthew E; Allen, Lee-Ann H; Jones, Bradley D

    2013-08-01

    The Francisella tularensis pathogenicity island (FPI) encodes many proteins that are required for virulence. Expression of these genes depends upon the FevR (PigR) regulator and its interactions with the MglA/SspA and RNA polymerase transcriptional complex. Experiments to identify how transcription of the FPI genes is activated have led to identification of mutations within the migR, trmE, and cphA genes that decrease FPI expression. Recent data demonstrated that the small alarmone ppGpp, produced by RelA and SpoT, is important for stabilizing MglA/SspA and FevR (PigR) interactions in Francisella. Production of ppGpp is commonly known to be activated by cellular and nutritional stress in bacteria, which indicates that cellular and nutritional stresses act as important signals for FPI activation. In this work, we demonstrate that mutations in migR, trmE, or cphA significantly reduce ppGpp accumulation. The reduction in ppGpp levels was similar for each of the mutants and correlated with a corresponding reduction in iglA reporter expression. In addition, we observed that there were differences in the ability of each of these mutants to replicate within various mammalian cells, indicating that the migR, trmE, and cphA genes are likely parts of different cellular stress response pathways in Francisella. These results also indicate that different nutritional and cellular stresses exist in different mammalian cells. This work provides new information to help understand how Francisella regulates its virulence genes in response to host cell environments, and it contributes to our growing knowledge of this highly successful bacterial pathogen.

  13. The subtype I-F CRISPR-Cas system influences pathogenicity island retention in Pectobacterium atrosepticum via crRNA generation and Csy complex formation.

    PubMed

    Richter, Corinna; Fineran, Peter C

    2013-12-01

    CRISPR (clustered regularly interspaced short palindromic repeats) arrays and Cas (CRISPR-associated) proteins confer acquired resistance against mobile genetic elements in a wide range of bacteria and archaea. The phytopathogen Pectobacterium atrosepticum SCRI1043 encodes a single subtype I-F CRISPR system, which is composed of three CRISPR arrays and the cas operon encoding Cas1, Cas3 (a Cas2-Cas3 fusion), Csy1, Csy2, Csy3 and Cas6f (Csy4). The CRISPR arrays are transcribed into pre-crRNA (CRISPR RNA) and then processed by Cas6f to generate crRNAs. Furthermore, the formation of Cas protein complexes has been implicated in both the interference and acquisition stages of defence. In the present paper, we discuss the development of tightly controlled 'programmable' CRISPR arrays as tools to investigate CRISPR-Cas function and the effects of chromosomal targeting. Finally, we address how chromosomal targeting by CRISPR-Cas can cause large-scale genome deletions, which can ultimately influence bacterial evolution and pathogenicity. PMID:24256239

  14. The subtype I-F CRISPR-Cas system influences pathogenicity island retention in Pectobacterium atrosepticum via crRNA generation and Csy complex formation.

    PubMed

    Richter, Corinna; Fineran, Peter C

    2013-12-01

    CRISPR (clustered regularly interspaced short palindromic repeats) arrays and Cas (CRISPR-associated) proteins confer acquired resistance against mobile genetic elements in a wide range of bacteria and archaea. The phytopathogen Pectobacterium atrosepticum SCRI1043 encodes a single subtype I-F CRISPR system, which is composed of three CRISPR arrays and the cas operon encoding Cas1, Cas3 (a Cas2-Cas3 fusion), Csy1, Csy2, Csy3 and Cas6f (Csy4). The CRISPR arrays are transcribed into pre-crRNA (CRISPR RNA) and then processed by Cas6f to generate crRNAs. Furthermore, the formation of Cas protein complexes has been implicated in both the interference and acquisition stages of defence. In the present paper, we discuss the development of tightly controlled 'programmable' CRISPR arrays as tools to investigate CRISPR-Cas function and the effects of chromosomal targeting. Finally, we address how chromosomal targeting by CRISPR-Cas can cause large-scale genome deletions, which can ultimately influence bacterial evolution and pathogenicity.

  15. A third secreted protein that is encoded by the enteropathogenic Escherichia coli pathogenicity island is required for transduction of signals and for attaching and effacing activities in host cells.

    PubMed Central

    Lai, L C; Wainwright, L A; Stone, K D; Donnenberg, M S

    1997-01-01

    Enteropathogenic Escherichia coli strains are able to signal host cells, cause dramatic cytoskeletal rearrangements, and adhere intimately to the cell surface in a process known as the attaching and effacing effect. A pathogenicity island of 35 kb known as the locus of enterocyte effacement (LEE) is necessary and sufficient for this effect. The LEE encodes an outer membrane adhesin called intimin, a type III secretion apparatus, and the EspA and EspB secreted proteins. The DNA sequence of the region between espA and espB revealed a new gene, espD. The product of espD was demonstrated by using a T7 expression system. We constructed a nonpolar mutation in espD and found that the mutant is incapable of the signal transduction events that lead to activation of the putative intimin receptor in host cells and that the mutant fails to induce the attaching and effacing effect. These phenotypes were restored to the mutant by complementation with a plasmid containing the cloned espD locus. We demonstrated by immunoblotting and microsequencing that the EspD protein is secreted via the type III apparatus. Thus, we describe a novel locus encoding a secreted protein that is required for attaching and effacing activity. PMID:9169753

  16. Fusaric acid modulates Type Three Secretion System of Salmonella enterica serovar Typhimurium.

    PubMed

    Li, Jianfang; Sun, Weiyang; Guo, Zhixing; Lu, Chunhua; Shen, Yuemao

    2014-07-11

    Natural small-molecule products are promising lead compounds for developing a generation of novel antimicrobials agents to meet the challenge of antibiotic-resistant pathogens. To facilitate the search for novel anti-virulence agents, we chose a virulence factor of Type Three Secretion System (T3SS) as a drug target to screen candidates from a small-molecule library in our laboratory. This study demonstrated fusaric acid had dramatically inhibitory effects on secretion of Salmonella island 1 (SPI-1) effector proteins and invasion of Salmonella into HeLa cells. Moreover, fusaric acid had no inhibitory effects on bacterial growth and viability of host cells. Protein HilA is a key regulator of SPI-1 in Salmonella, which affects transcription of SPI-1 effectors and SPI-1 apparatus genes. In this study, fusaric acid (FA) did not affect secretion of SPI-1 effectors in HilA over-expressed strain, suggesting it did not affect the transcription of SPI-1. In addition, fusaric acid did not affect the protein level of apparatus protein PrgH in SPI-1 needle complex. As a result, we proposed fusaric acid had an inhibitory effect on SPI-1 probably depending on its influence on SicA/InvF. In summary, fusaric acid is a novel inhibitor of T3SS with potential for further developing novel anti-virulence agents.

  17. Canary Islands

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This easterly looking view shows the seven major volcanic islands of the Canary Island chain (28.0N, 16.5W) and offers a unique view of the islands that have become a frequent vacation spot for Europeans. The northwest coastline of Africa, (Morocco and Western Sahara), is visible in the background. Frequently, these islands create an impact on local weather (cloud formations) and ocean currents (island wakes) as seen in this photo.

  18. Bloodborne pathogens

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000453.htm Bloodborne pathogens To use the sharing features on this page, please enable JavaScript. A pathogen is something that causes disease. Germs that can ...

  19. Multiple genes in the left half of the cag pathogenicity island of Helicobacter pylori are required for tyrosine kinase-dependent transcription of interleukin-8 in gastric epithelial cells.

    PubMed

    Li, S D; Kersulyte, D; Lindley, I J; Neelam, B; Berg, D E; Crabtree, J E

    1999-08-01

    Helicobacter pylori strains that contain the cag pathogenicity island (PAI) elicit increased synthesis of gastric C-X-C chemokines, promote neutrophilic infiltration into the gastric epithelium, and stimulate the synthesis of interleukin-8 (IL-8) in cultured gastric epithelial cells. To investigate the effects of cag PAI genes on the transcription of the IL-8 gene, the Kato-3 gastric epithelial cell line was stably transfected with plasmid DNA containing the IL-8 gene promoter fused to a luciferase reporter gene. The resulting reporter cell line, L5F11, was used to monitor the effects of infection in cell culture by H. pylori 26695 and isogenic derivatives with null mutations in genes in the cag PAI on transcription of the IL-8 gene. We found that null mutations in eight open reading frames, including homologs of the Agrobacterium virB9, virB10, and virB11 genes, in the left half of the cag PAI abrogated the induction of IL-8 gene transcription. Further studies with the L5F11 cell line showed that IL-8 gene transcription induced by H. pylori was blocked by the protein tyrosine kinase inhibitor herbimycin A but not by the protein kinase C inhibitor calphostin C or by the protein kinase G inhibitor KT5823. IL-8 gene transcription in L5F11 cells could also be induced by the cytokine tumor necrosis factor alpha (TNF-alpha) without exposure to H. pylori. This TNF-alpha-induced IL-8 transcription was inhibited by the protein kinase A inhibitor H7, which had no significant effect on H. pylori-induced IL-8 transcription. These studies show that multiple genes in the left half of the cag PAI are essential for the transcription of the IL-8 gene in gastric epithelial cells and that this depends on protein tyrosine kinase activation. PMID:10417153

  20. Genomic analysis of a pathogenicity island in uropathogenic Escherichia coli CFT073: distribution of homologous sequences among isolates from patients with pyelonephritis, cystitis, and Catheter-associated bacteriuria and from fecal samples.

    PubMed

    Guyer, D M; Kao, J S; Mobley, H L

    1998-09-01

    Urinary tract infection is the most frequently diagnosed kidney and urologic disease and Escherichia coli is by far the most common etiologic agent. Uropathogenic strains have been shown to contain blocks of DNA termed pathogenicity islands (PAIs) which contribute to their virulence. We have defined one of these regions of DNA within the chromosome of a highly virulent E. coli strain, CFT073, isolated from the blood and urine of a woman with acute pyelonephritis. The 57,988-bp stretch of DNA has characteristics which define PAIs, including a size greater than 30 kb, the presence of insertion sequences, distinct segmentation of K-12 and J96 origin, GC content (42.9%) different from that of total genomic DNA (50.8%), and the presence of virulence genes (hly and pap). Within this region, we have identified 44 open reading frames; of these 44, 10 are homologous to entries in the complete K-12 genome sequence, 4 are nearly identical to the sequences of E. coli J96 encoding the HlyA hemolysin, 11 encode P fimbriae, and 19 show no homology to J96 or K-12 entries. To determine whether sequences found within the junctions of the PAI of CFT073 were common to other uropathogenic strains of E. coli, 11 probes were isolated along the length of the PAI and were hybridized to dot blots of genomic DNA isolated from clinical isolates (67 from patients with acute pyelonephritis, 38 from patients with cystitis, 49 from patients with catheter-associated bacteriuria, and 27 from fecal samples). These sequences were found significantly more often in strains associated with the clinical syndromes of acute pyelonephritis (79%) and cystitis (82%) than in those associated with catheter-associated bacteriuria (58%) and in fecal strains (22%) (P < 0.001). From these regions, we have identified a putative iron transport system and genes other than hly and pap that may contribute to the virulent phenotype of uropathogenic E. coli strains.

  1. SseA is a chaperone for the SseB and SseD translocon components of the Salmonella pathogenicity-island-2-encoded type III secretion system.

    PubMed

    Ruiz-Albert, Javier; Mundy, Rosanna; Yu, Xiu-Jun; Beuzón, Carmen R; Holden, David W

    2003-05-01

    The type III secretion system (TTSS) encoded by the Salmonella pathogenicity island 2 (SPI-2) is required for bacterial replication inside macrophages and for systemic infection in mice. Many TTSS secreted proteins, including effectors and components of the translocon, require chaperones which promote their stability, prevent their premature interactions or facilitate their secretion. In this study, the function of the first gene (sseA) of one of the SPI-2 operons (sseA-G) was investigated. This operon includes genes that encode translocon components (SseB, SseC and SseD), translocated proteins (SseF and SseG) and putative chaperones (SscA and SscB). sseA encodes a 12.5 kDa protein with a C-terminal region with the potential to form a coiled-coil structure, but no sequence similarity to other proteins. Mutation of sseA results in severe virulence attenuation and an intracellular replication defect. It is shown here that SseA is not a secreted protein, but is required for SPI-2-dependent translocation of two effector proteins (SifA and PipB). Furthermore, the translocon components SseB and SseD were not detected in an sseA mutant strain. By using a yeast two-hybrid assay and column binding experiments, it is demonstrated that SseA interacts directly with SseB and SseD. These results indicate that SseA is a chaperone for SseB and SseD. The inability of an sseA mutant to assemble the SPI-2 TTSS translocon accounts for its high level of virulence attenuation in vivo. To the authors' knowledge, this is the first chaperone described for the SPI-2 TTSS.

  2. IslandViewer update: Improved genomic island discovery and visualization.

    PubMed

    Dhillon, Bhavjinder K; Chiu, Terry A; Laird, Matthew R; Langille, Morgan G I; Brinkman, Fiona S L

    2013-07-01

    IslandViewer (http://pathogenomics.sfu.ca/islandviewer) is a web-accessible application for the computational prediction and analysis of genomic islands (GIs) in bacterial and archaeal genomes. GIs are clusters of genes of probable horizontal origin and are of high interest because they disproportionately encode virulence factors and other adaptations of medical, environmental and industrial interest. Many computational tools exist for the prediction of GIs, but three of the most accurate methods are available in integrated form via IslandViewer: IslandPath-DIMOB, SIGI-HMM and IslandPick. IslandViewer GI predictions are precomputed for all complete microbial genomes from National Center for Biotechnology Information, with an option to upload other genomes and/or perform customized analyses using different settings. Here, we report recent changes to the IslandViewer framework that have vastly improved its efficiency in handling an increasing number of users, plus better facilitate custom genome analyses. Users may also now overlay additional annotations such as virulence factors, antibiotic resistance genes and pathogen-associated genes on top of current GI predictions. Comparisons of GIs between user-selected genomes are now facilitated through a highly requested side-by-side viewer. IslandViewer improvements aim to provide a more flexible interface, coupled with additional highly relevant annotation information, to aid analysis of GIs in diverse microbial species.

  3. Galapagos Islands

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color image of the Galapagos Islands was acquired on March 12, 2002, by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite. The Galapagos Islands, which are part of Ecuador, sit in the Pacific Ocean about 1000 km (620 miles) west of South America. As the three craters on the largest island (Isabela Island) suggest, the archipelago was created by volcanic eruptions, which took place millions of years ago. Unlike most remote islands in the Pacific, the Galapagos have gone relatively untouched by humans over the past few millennia. As a result, many unique species have continued to thrive on the islands. Over 95 percent of the islands' reptile species and nearly three quarters of its land bird species cannot be found anywhere else in the world. Two of the more well known are the Galapagos giant tortoise and marine iguanas. The unhindered evolutionary development of the islands' species inspired Charles Darwin to begin The Origin of Species eight years after his visit there. To preserve the unique wildlife on the islands, the Ecuadorian government made the entire archipelago a national park in 1959. Each year roughly 60,000 tourists visit these islands to experience what Darwin did over a century and a half ago. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  4. Analysis of the intactness of Helicobacter pylori cag pathogenicity island in Iranian strains by a new PCR-based strategy and its relationship with virulence genotypes and EPIYA motifs.

    PubMed

    Yadegar, Abbas; Alebouyeh, Masoud; Zali, Mohammad Reza

    2015-10-01

    Variants of the Helicobacter pylori cag pathogenicity island (cagPAI) and certain virulence genotypes have been proposed to be associated with different gastric disorders. In the present study, we designed a new PCR-based strategy to investigate the intactness of cagPAI in Iranian patients using highly specific primer sets spanning the cagPAI region. The possible relationship between the cagPAI status of the strains and clinical outcomes was also determined. We also characterized virulence genotypes (cagL, cagA, vacA, babA2 and sabA) and variants of CagA EPIYA motifs in these strains. H. pylori was detected in 61 out of 126 patients with various gastroduodenal diseases. The cagL, cagA, vacA s1m1, vacA s1m2, vacA s2m2, babA2, and sabA genotypes were detected in 96.7%, 85.2%, 29.5%, 45.9%, 24.6%, 96.7%, and 83.6% of the strains, respectively. Among the 52 cagA-positive strains, EPIYA motifs ABC, ABCC, ABCCC, and mixed types were orderly detected in the 39, 7, 1, and 5 strains. The cagPAI positivity included both intact and partially deleted, with the overall frequencies of 70.5% and 26.2%, respectively. The majority of the strains from patients with PUD (87.5%), gastric erosion (83.3%) and cancer (80%) presented an intact cagPAI, while a lower frequency of cagPAI intactness was detected in gastritis patients (61.1%). However, no significant relationship was found between the possession of intact cagPAI and clinical outcomes. Furthermore, we found that cagA and vacA s1m1 genotypes were significantly correlated with intact cagPAI (P=0.015 and P=0.012). A significant correlation was also found between EPIYA-ABC and intact cagPAI (P=0.010). The proposed PCR-based scheme was found to be useful for determining the intactness of cagPAI. Our findings also indicate that the cagPAI appears to be intact and rather conserved in majority of Iranian strains. Finally, our study proposed that H. pylori strains with partially deleted cagPAI were less likely to cause severe diseases

  5. GIPSy: Genomic island prediction software.

    PubMed

    Soares, Siomar C; Geyik, Hakan; Ramos, Rommel T J; de Sá, Pablo H C G; Barbosa, Eudes G V; Baumbach, Jan; Figueiredo, Henrique C P; Miyoshi, Anderson; Tauch, Andreas; Silva, Artur; Azevedo, Vasco

    2016-08-20

    Bacteria are highly diverse organisms that are able to adapt to a broad range of environments and hosts due to their high genomic plasticity. Horizontal gene transfer plays a pivotal role in this genome plasticity and in evolution by leaps through the incorporation of large blocks of genome sequences, ordinarily known as genomic islands (GEIs). GEIs may harbor genes encoding virulence, metabolism, antibiotic resistance and symbiosis-related functions, namely pathogenicity islands (PAIs), metabolic islands (MIs), resistance islands (RIs) and symbiotic islands (SIs). Although many software for the prediction of GEIs exist, they only focus on PAI prediction and present other limitations, such as complicated installation and inconvenient user interfaces. Here, we present GIPSy, the genomic island prediction software, a standalone and user-friendly software for the prediction of GEIs, built on our previously developed pathogenicity island prediction software (PIPS). We also present four application cases in which we crosslink data from literature to PAIs, MIs, RIs and SIs predicted by GIPSy. Briefly, GIPSy correctly predicted the following previously described GEIs: 13 PAIs larger than 30kb in Escherichia coli CFT073; 1 MI for Burkholderia pseudomallei K96243, which seems to be a miscellaneous island; 1 RI of Acinetobacter baumannii AYE, named AbaR1; and, 1 SI of Mesorhizobium loti MAFF303099 presenting a mosaic structure. GIPSy is the first life-style-specific genomic island prediction software to perform analyses of PAIs, MIs, RIs and SIs, opening a door for a better understanding of bacterial genome plasticity and the adaptation to new traits. PMID:26376473

  6. GIPSy: Genomic island prediction software.

    PubMed

    Soares, Siomar C; Geyik, Hakan; Ramos, Rommel T J; de Sá, Pablo H C G; Barbosa, Eudes G V; Baumbach, Jan; Figueiredo, Henrique C P; Miyoshi, Anderson; Tauch, Andreas; Silva, Artur; Azevedo, Vasco

    2016-08-20

    Bacteria are highly diverse organisms that are able to adapt to a broad range of environments and hosts due to their high genomic plasticity. Horizontal gene transfer plays a pivotal role in this genome plasticity and in evolution by leaps through the incorporation of large blocks of genome sequences, ordinarily known as genomic islands (GEIs). GEIs may harbor genes encoding virulence, metabolism, antibiotic resistance and symbiosis-related functions, namely pathogenicity islands (PAIs), metabolic islands (MIs), resistance islands (RIs) and symbiotic islands (SIs). Although many software for the prediction of GEIs exist, they only focus on PAI prediction and present other limitations, such as complicated installation and inconvenient user interfaces. Here, we present GIPSy, the genomic island prediction software, a standalone and user-friendly software for the prediction of GEIs, built on our previously developed pathogenicity island prediction software (PIPS). We also present four application cases in which we crosslink data from literature to PAIs, MIs, RIs and SIs predicted by GIPSy. Briefly, GIPSy correctly predicted the following previously described GEIs: 13 PAIs larger than 30kb in Escherichia coli CFT073; 1 MI for Burkholderia pseudomallei K96243, which seems to be a miscellaneous island; 1 RI of Acinetobacter baumannii AYE, named AbaR1; and, 1 SI of Mesorhizobium loti MAFF303099 presenting a mosaic structure. GIPSy is the first life-style-specific genomic island prediction software to perform analyses of PAIs, MIs, RIs and SIs, opening a door for a better understanding of bacterial genome plasticity and the adaptation to new traits.

  7. AraC/XylS family members, HilD and HilC, directly activate virulence gene expression independently of HilA in Salmonella typhimurium.

    PubMed

    Akbar, Samina; Schechter, Lisa M; Lostroh, C Phoebe; Lee, Catherine A

    2003-02-01

    Salmonella typhimurium is a Gram-negative enteric pathogen that can infect intestinal epithelial cells and induce inflammation of the intestinal mucosa. These processes are mediated by a type III secretion system (TTSS), which is encoded on Salmonella pathogenicity island 1 (SPI1). Previous studies showed that four SPI1-encoded transcriptional regulators, HilD, HilC, HilA and InvF, act in an ordered fashion to co-ordinately activate expression of the SPI1 TTSS. HilD and HilC derepress hilA transcription. HilA activates invF as well as SPI1 genes that encode components of the TTS apparatus. InvF then activates genes that encode proteins secreted by the SPI1 TTS apparatus. In this scheme, HilD and HilC indirectly activate expression of the SPI1 TTS apparatus and its secreted substrates by affecting hilA expression. Here, we report that HilD and HilC can also activate expression of a subset of SPI1 genes independently of HilA. Our studies show that HilD and HilC activate transcription of invF from a promoter that is far upstream of its HilA-dependent promoter. This activation is most probably through direct binding of HilD and HilC to sequences upstream and downstream of this alternative HilA-independent promoter. We conclude that HilD and HilC have a second role in SPI1 gene regulation that is separate from their role in co-ordinating expression of the SPI1 TTSS through hilA.

  8. Akpatok Island

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Akpatok Island lies in Ungava Bay in northern Quebec, Canada. Accessible only by air, Akpatok Island rises out of the water as sheer cliffs that soar 500 to 800 feet (150 to 243 m) above the sea surface. The island is an important sanctuary for cliff-nesting seabirds. Numerous ice floes around the island attract walrus and whales, making Akpatok a traditional hunting ground for native Inuit people. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on January 22, 2001. Image provided by the USGS EROS Data Center Satellite Systems Branch

  9. [Research progress in pathogenicity of Ureaplasma urealyticum].

    PubMed

    Huang, Jun; Zhang, Jun; Song, Tiejun; Xie, Xinyou

    2013-07-01

    Ureaplasma urealyticum (UU) is closely related to human diseases including non-gonococcal urethritis (NGU), infertility, premature membranes and neonatal bronchopulmonary dysplasia. Researches on the pathogenicity of UU have become a hot topic in recent years, and suggest that many potential pathogenicity genes or putative pathogenicity islands are involved in its virulence. Moreover, the biovar and serum types of UU, the infection concentration and the state of the host immune system are also important to determine whether UU can cause human disease or not. In this article the recent progress of researches in the pathogenicity of UU is reviewed.

  10. Island Hopping

    ERIC Educational Resources Information Center

    Bennett, Gayle

    2009-01-01

    At some institutions, it may feel as though faculty live on one island and advancement staff on another. The islands form part of an archipelago, and they exchange ambassadors and send emissaries occasionally, but interactions are limited. It may even seem as though the two groups speak different languages, deal in different currencies, and abide…

  11. Anatahan Island

    Atmospheric Science Data Center

    2013-04-19

    ... of the Mariana Islands in 1914 (the first year of World War l) and Germany released the islands to Japan in 1919. Japan received a ... States by the United Nations. The wreckage of a World War II B-29 Superfortress, a four-engine propeller-driven bomber, lies on the north ...

  12. Pathogen intelligence.

    PubMed

    Steinert, Michael

    2014-01-01

    Different species inhabit different sensory worlds and thus have evolved diverse means of processing information, learning and memory. In the escalated arms race with host defense, each pathogenic bacterium not only has evolved its individual cellular sensing and behavior, but also collective sensing, interbacterial communication, distributed information processing, joint decision making, dissociative behavior, and the phenotypic and genotypic heterogeneity necessary for epidemiologic success. Moreover, pathogenic populations take advantage of dormancy strategies and rapid evolutionary speed, which allow them to save co-generated intelligent traits in a collective genomic memory. This review discusses how these mechanisms add further levels of complexity to bacterial pathogenicity and transmission, and how mining for these mechanisms could help to develop new anti-infective strategies. PMID:24551600

  13. Pathogen intelligence

    PubMed Central

    Steinert, Michael

    2014-01-01

    Different species inhabit different sensory worlds and thus have evolved diverse means of processing information, learning and memory. In the escalated arms race with host defense, each pathogenic bacterium not only has evolved its individual cellular sensing and behavior, but also collective sensing, interbacterial communication, distributed information processing, joint decision making, dissociative behavior, and the phenotypic and genotypic heterogeneity necessary for epidemiologic success. Moreover, pathogenic populations take advantage of dormancy strategies and rapid evolutionary speed, which allow them to save co-generated intelligent traits in a collective genomic memory. This review discusses how these mechanisms add further levels of complexity to bacterial pathogenicity and transmission, and how mining for these mechanisms could help to develop new anti-infective strategies. PMID:24551600

  14. Devon Island

    Atmospheric Science Data Center

    2013-04-17

    article title:  Mars Researchers Rendezvous on Remote Arctic Island   ... each summer since 1999, researchers from NASA's Haughton-Mars Project and the Mars Society reside at this "polar desert" location to study the geologic and ...

  15. Island of Okinawa, Japan

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The island of Okinawa, (26.5N, 128.0E) largest of the Ryukyu Islands, Japan. The Ryukyu island group lies south of the main home islands of Japan in an arc towards the Chinese island Republic of Taiwan. As is typical throughout the Japanese home islands, intense urban development can be observed all over the island in this near vertical view.

  16. Bile Acids Function Synergistically To Repress Invasion Gene Expression in Salmonella by Destabilizing the Invasion Regulator HilD.

    PubMed

    Eade, Colleen R; Hung, Chien-Che; Bullard, Brian; Gonzalez-Escobedo, Geoffrey; Gunn, John S; Altier, Craig

    2016-08-01

    Salmonella spp. are carried by and can acutely infect agricultural animals and humans. After ingestion, salmonellae traverse the upper digestive tract and initiate tissue invasion of the distal ileum, a virulence process carried out by the type III secretion system encoded within Salmonella pathogenicity island 1 (SPI-1). Salmonellae coordinate SPI-1 expression with anatomical location via environmental cues, one of which is bile, a complex digestive fluid that causes potent repression of SPI-1 genes. The individual components of bile responsible for SPI-1 repression have not been previously characterized, nor have the bacterial signaling processes that modulate their effects been determined. Here, we characterize the mechanism by which bile represses SPI-1 expression. Individual bile acids exhibit repressive activity on SPI-1-regulated genes that requires neither passive diffusion nor OmpF-mediated entry. By using genetic methods, the effects of bile and bile acids were shown to require the invasion gene transcriptional activator hilD and to function independently of known upstream signaling pathways. Protein analysis techniques showed that SPI-1 repression by bile acids is mediated by posttranslational destabilization of HilD. Finally, we found that bile acids function synergistically to achieve the overall repressive activity of bile. These studies demonstrate a common mechanism by which diverse environmental cues (e.g., certain short-chain fatty acids and bile acids) inhibit SPI-1 expression. These data provide information relevant to Salmonella pathogenesis during acute infection in the intestine and during chronic infection of the gallbladder and inform the basis for development of therapeutics to inhibit invasion as a means of repressing Salmonella pathogenicity.

  17. Genomic Island Identification Software v 1.0

    2014-08-25

    Genomic islands are key mobile DNA elements in bacterial evolution, that can distinguish pathogenic strains from each other, or distinguish pathogenic strains from non-pathogenic strains. Their detection in genomes is a challenging problem. We present 3 main software components that attack the island detection problem on two different bases: 1) the preference of islands to insert in chromosomal tRNA or tmRNA genes (islander.pl), and 2) islands’ sporadic occurrence among closely related strains. The latter principlemore » is employed in both an algorithm (learnedPhyloblocks.pl) and a visualization method (panGenome.pl). Component islander.pl finds islands based on their preference for a particular target gene type. We annotate each tRNA and tmRNA gene, find fragments of each such gene as candidates for the distal ends of islands, and filter candidates to remove false positives. Component learnedPhyloblocks.pl uses islands found by islander.pl and other methods as a training set to find new islands. Reference genomes are aligned using mugsy, then the “phylotypes” or patterns of occurrence in the reference set are determined for each position in the target genome, and those phylotypes most enriched in the training set of islands are followed to detect yet more islands. Component panGenome.pl produces a big-data visualization of the chromosomally-ordered “pan-genome”, that includes every gene of every reference genome (x-axis, pan-genome order; y-axis, reference genomes; color-coding, gene presence/absence etc.), islands appearing as dark patches.« less

  18. Genomic Island Identification Software v 1.0

    SciTech Connect

    None, None

    2014-08-25

    Genomic islands are key mobile DNA elements in bacterial evolution, that can distinguish pathogenic strains from each other, or distinguish pathogenic strains from non-pathogenic strains. Their detection in genomes is a challenging problem. We present 3 main software components that attack the island detection problem on two different bases: 1) the preference of islands to insert in chromosomal tRNA or tmRNA genes (islander.pl), and 2) islands’ sporadic occurrence among closely related strains. The latter principle is employed in both an algorithm (learnedPhyloblocks.pl) and a visualization method (panGenome.pl). Component islander.pl finds islands based on their preference for a particular target gene type. We annotate each tRNA and tmRNA gene, find fragments of each such gene as candidates for the distal ends of islands, and filter candidates to remove false positives. Component learnedPhyloblocks.pl uses islands found by islander.pl and other methods as a training set to find new islands. Reference genomes are aligned using mugsy, then the “phylotypes” or patterns of occurrence in the reference set are determined for each position in the target genome, and those phylotypes most enriched in the training set of islands are followed to detect yet more islands. Component panGenome.pl produces a big-data visualization of the chromosomally-ordered “pan-genome”, that includes every gene of every reference genome (x-axis, pan-genome order; y-axis, reference genomes; color-coding, gene presence/absence etc.), islands appearing as dark patches.

  19. Siberian Islands

    Atmospheric Science Data Center

    2013-04-16

    ... Distinguishing Clouds from Ice over the East Siberian Sea, Russia     View Larger Image ... ocean are visible. The East Siberian Sea is part of the Arctic Ocean and is ice-covered most of the year. The New Siberian Islands are ...

  20. Hawaiian Islands

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This Multiangle Imaging Spectro-Radiometer (MISR) image of five Hawaiian Islands was acquired by the instrument's vertical- viewing (nadir) camera on June 3, 2000. The image shows the islands of Oahu, Molokai, Lanai, Maui, and Kahoolawe. The prevailing Pacific trade winds bring higher levels of rainfall to the eastern slopes of the islands, leading to a greater abundance of vegetation on the windward coasts. The small change in observation angle across the nadir camera's field-of- view causes the right-hand portion of the image to be more affected by Sun glint, making the ocean surface appear brighter. Oahu is the westernmost of the islands seen in this image. Waikiki Beach and the city of Honolulu are located on the southern shore, to the west of Diamond Head caldera. MISR is one of several Earth-observing instruments on the Terra satellite, launched in December 1999. The Terra spacecraft, the flagship of a fleet of satellites dedicated to understanding our global environment, is part of NASA's Earth Sciences Enterprise, a long-term research program dedicated to understanding how human-induced and natural changes affect our world. Image courtesy NASA/GSFC/JPL, MISR Team

  1. Inherent Variability of Growth Media Impacts the Ability of Salmonella Typhimurium to Interact with Host Cells

    PubMed Central

    Sridhar, Sushmita; Steele-Mortimer, Olivia

    2016-01-01

    Efficient invasion of non-phagocytic cells, such as intestinal epithelial cells, by Salmonella Typhimurium is dependent on the Salmonella Pathogenicity Island 1 (SPI-1)-encoded Type Three Secretion System. The environmental cues involved in SPI-1 induction are not well understood. In vitro, various conditions are used to induce SPI-1 and the invasive phenotype. Although lysogeny broth (LB) is widely used, multiple formulations exist, and variation can arise due to intrinsic differences in complex components. Minimal media are also susceptible to variation. Still, the impact of these inconsistencies on Salmonella virulence gene expression has not been well studied. The goal of this project is to identify growth conditions in LB and minimal medium that affect SPI-1 induction in vitro using both whole population and single cell analysis. Here we show, using a fluorescent reporter of the SPI-1 gene prgH, that growth of Salmonella in LB yields variable induction. Deliberate modification of media components can influence the invasive profile. Finally, we demonstrate that changes in SPI-1 inducing conditions can affect the ability of Salmonella to replicate intracellularly. These data indicate that the specific media growth conditions impact how the bacteria interact with host cells. PMID:27280414

  2. Inherent Variability of Growth Media Impacts the Ability of Salmonella Typhimurium to Interact with Host Cells.

    PubMed

    Sridhar, Sushmita; Steele-Mortimer, Olivia

    2016-01-01

    Efficient invasion of non-phagocytic cells, such as intestinal epithelial cells, by Salmonella Typhimurium is dependent on the Salmonella Pathogenicity Island 1 (SPI-1)-encoded Type Three Secretion System. The environmental cues involved in SPI-1 induction are not well understood. In vitro, various conditions are used to induce SPI-1 and the invasive phenotype. Although lysogeny broth (LB) is widely used, multiple formulations exist, and variation can arise due to intrinsic differences in complex components. Minimal media are also susceptible to variation. Still, the impact of these inconsistencies on Salmonella virulence gene expression has not been well studied. The goal of this project is to identify growth conditions in LB and minimal medium that affect SPI-1 induction in vitro using both whole population and single cell analysis. Here we show, using a fluorescent reporter of the SPI-1 gene prgH, that growth of Salmonella in LB yields variable induction. Deliberate modification of media components can influence the invasive profile. Finally, we demonstrate that changes in SPI-1 inducing conditions can affect the ability of Salmonella to replicate intracellularly. These data indicate that the specific media growth conditions impact how the bacteria interact with host cells.

  3. Streamlined Island

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-514, 15 October 2003

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture shows a streamlined island in Marte Vallis, a large outflow channel system that crosses the 180oW meridian between the Elysium and Amazonis regions of Mars. The flow patterns on the floor of Marte Vallis might be the remains of lava flows or mud flows. Marte is the Spanish word for Mars. Most of the largest valleys on the red planet are named for 'Mars' in various languages. This island is located near 21.8oN, 175.3oW. The picture covers an area 3 km (1.9 mi) wide and is illuminated by sunlight from the lower left.

  4. Classifying Pacific islands

    NASA Astrophysics Data System (ADS)

    Nunn, Patrick D.; Kumar, Lalit; Eliot, Ian; McLean, Roger F.

    2016-12-01

    An earth-science-based classification of islands within the Pacific Basin resulted from the preparation of a database describing the location, area, and type of 1779 islands, where island type is determined as a function of the prevailing lithology and maximum elevation of each island, with an island defined as a discrete landmass composed of a contiguous land area ≥1 ha (0.01 km2) above mean high-water level. Reefs lacking islands and short-lived (<20 years) transient islands are not included. The principal aim of the classification is to assess the spatial diversity of the geologic and geomorphic attributes of Pacific islands. It is intended to be valid at a regional scale and based on two attributes: five types of lithology (volcanic, limestone, composite, continental, surficial) and a distinction between high and low islands. These attributes yielded eight island types: volcanic high and low islands; limestone high and low islands; composite high and low islands; reef (including all unconsolidated) islands; and continental islands. Most common are reef islands (36 %) and volcanic high islands (31 %), whereas the least common are composite low islands (1 %). Continental islands, 18 of the 1779 islands examined, are not included in maps showing the distribution of island attributes and types. Rationale for the spatial distributions of the various island attributes is drawn from the available literature and canvassed in the text. With exception of the few continental islands, the distribution of island types is broadly interpretable from the proximity of island-forming processes. It is anticipated the classification will become the basis for more focused investigation of spatial variability of the climate and ocean setting as well as the biological attributes of Pacific islands. It may also be used in spatial assessments of second-order phenomena associated with the islands, such as their vulnerability to various disasters, coastal erosion, or ocean pollution as

  5. Pili in gram-positive pathogens.

    PubMed

    Telford, John L; Barocchi, Michèle A; Margarit, Immaculada; Rappuoli, Rino; Grandi, Guido

    2006-07-01

    Most bacterial pathogens have long filamentous structures known as pili or fimbriae extending from their surface. These structures are often involved in the initial adhesion of the bacteria to host tissues during colonization. In gram-negative bacteria, pili are typically formed by non-covalent interactions between pilin subunits. By contrast, the recently discovered pili in gram-positive pathogens are formed by covalent polymerization of adhesive pilin subunits. Evidence from studies of pili in the three principal streptococcal pathogens of humans indicates that the genes that encode the pilin subunits and the enzymes that are required for the assembly of these subunits into pili have been acquired en bloc by the horizontal transfer of a pathogenicity island.

  6. Pathogene Mikroorganismen

    NASA Astrophysics Data System (ADS)

    Wagner, Martin

    Infektionen, die vom Tier auf den Menschen übertragen werden, werden als Zoonosen bezeichnet. Pathogene Mikroorganismen können entweder durch Mensch-Mensch, Mensch-Tier-Kontakt oder durch Kontakt mit kontaminierten Vektoren übertragen werden [39]. Vektoren können einerseits belebt (z. B. blutsaugende Insekten), andererseits unbelebt sein. Kontaminierte Lebensmittel und Wasser gehören zu den wichtigsten unbelebten Vektoren. Neben Lebensmitteln können aber auch kontaminierte Gegenstände oder der Kontakt mit Kontaminationsquellen in der Umwelt Auslöser von Krankheitsfällen sein. Weltweit sind mehr als 1400 krankheitsverursachende biologische Agentien bekannt, von denen über 60 % ein zoonotisches Potenzial aufweisen. Als Ergebnis von Expertengesprächen wurde kürzlich berichtet, dass etwa 3 bis 4, meist virale, neu auftretende Infektionskrankheiten ("emerging diseases“) pro Jahr erwartet werden können [15]. Es handelt sich bei diesen Vorgängen aber nicht nur um das Auftauchen vollkommen neuer oder unbeschriebener Spezies, sondern auch um evolutionsbedingte Anpassungen von mikrobiellen Populationen an neue Bedingungen in ihrem Ökosystem [7]. Molekulare Analysen an Umweltchlamydien erbrachten Hinweise, dass die Evolution erste genetische Pathogenitätsmerkmale in dieser Spezies schon vor 700 Mio. Jahren entstehen ließ [14]. Viele Faktoren befeuern den Prozess der Anpassung, unter anderem auch alle Strategien, mit denen der Mensch seit Jahrtausenden versucht, Lebensmittel sicher und haltbar zu machen. Als die treibenden Kräfte des Auftretens neuer Krankheitserreger werden in der Gegenwart vor allem das sich ändernde Weltklima, die globalen Warenströme und die sich verändernden Konsumgewohnheiten genannt. Es steht auch außer Zweifel, dass viele dieser Erreger Tiere als ihr natürliches Reservoir haben werden, d. h. Zoonosen im klassischen Sinne sind [15].

  7. Solomon Islands.

    PubMed

    1988-06-01

    The Solomon Islands, which form an archipelago in the Southwest Pacific about 1900 km northeast of Australia, are described. Included are brief descriptions about such points as geography, people, history, type of government, political conditions, economy, and foreign relations. In 1987 the population was 301,180 (49% under age 14); the annual growth rate was 3.67%. The infant mortality rate is 46/1000; the life expectancy, 54 years. Health conditions in the Solomons generally are adequate, and the country does not suffer from serious endemic diseases other than malaria, in both the vivax and falsiparum strains. Hospitals and pharmacies are limited to population centers and missions. PMID:12177986

  8. Island of Kauai, Hawaii

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The island of Kauai, of the Hawaiian Island archipelago (22.0N, 159.5W) peeks out from scattered cloud cover. The island's volcanic origins are easily seen by the distinctive lava flow topography and lush vegetation.

  9. Common themes in the genome strategies of pathogens.

    PubMed

    Lawrence, Jeffrey G

    2005-12-01

    Genomes of pathogenic bacteria evolve by large-scale changes in gene inventory. The continual acquisition of genomic islands, which refines their metabolic arsenal, is offset by gene loss. Far from this being a passive deletion of genes no longer useful to pathogens, the removal of genes encoding problematic metabolic process and immunogenic surface antigens might be strongly beneficial. Genomes of virulent eukaryotes show the footprint of similar genomic alterations, including acquisition of genes by lateral transfer, and genome degradation in obligate pathogens. These common features suggest that unicellular pathogens share common strategies for adaptation.

  10. Evolution of Bacterial Pathogens Within the Human Host.

    PubMed

    Bliven, Kimberly A; Maurelli, Anthony T

    2016-02-01

    Selective pressures within the human host, including interactions with innate and adaptive immune responses, exposure to medical interventions such as antibiotics, and competition with commensal microbiota all facilitate the evolution of bacterial pathogens. In this chapter, we present examples of pathogen strategies that emerged as a result of selective pressures within the human host niche and discuss the resulting coevolutionary "arms race" between these organisms. In bacterial pathogens, many of the genes responsible for these strategies are encoded on mobile pathogenicity islands or plasmids, underscoring the importance of horizontal gene transfer in the emergence of virulent microbial species.

  11. Evolution of Bacterial Pathogens within the Human Host

    PubMed Central

    Bliven, Kimberly A.; Maurelli, Anthony T.

    2015-01-01

    Selective pressures within the human host, including interactions with innate and adaptive immune responses, exposure to medical interventions such as antibiotics, and competition with commensal microbiota all facilitate the evolution of bacterial pathogens. In this chapter, we present examples of pathogen strategies which emerged as a result of selective pressures within the human host niche, and discuss the resulting co-evolutionary ‘arms race’ between these organisms. In bacterial pathogens, many of the genes responsible for these strategies are encoded on mobile pathogenicity islands (PAIs) or plasmids, underscoring the importance of horizontal gene transfer (HGT) in the emergence of virulent microbial species. PMID:26999399

  12. Cytosporone B, an inhibitor of the type III secretion system of Salmonella enterica serovar Typhimurium.

    PubMed

    Li, Jianfang; Lv, Chao; Sun, Weiyang; Li, Zhenyu; Han, Xiaowei; Li, Yaoyao; Shen, Yuemao

    2013-05-01

    Bacterial virulence factors have been increasingly regarded as attractive targets for development of novel antibacterial agents. Virulence inhibitors are less likely to generate bacterial resistance, which makes them superior to traditional antibiotics that target bacterial viability. Salmonella enterica serovar Typhimurium, an important food-borne human pathogen, has type III secretion system (T3SS) as its major virulence factor. T3SS secretes effector proteins to facilitate invasion into host cells. In this study, we identified several analogs of cytosporone B (Csn-B) that strongly block the secretion of Salmonella pathogenicity island 1 (SPI-1)-associated effector proteins, without affecting the secretion of flagellar protein FliC in vitro. Csn-B and two other derivatives exhibited a strong inhibitory effect on SPI-1-mediated invasion to HeLa cells, while no significant toxicity to bacteria was observed. Nucleoid proteins Hha and H-NS bind to the promoters of SPI-1 regulator genes hilD, hilC, and rtsA to repress their expression and consequently regulate the expression of SPI-1 apparatus and effector genes. We found that Csn-B upregulated the transcription of hha and hns, implying that Csn-B probably affected the secretion of effectors through the Hha-H-NS regulatory pathway. In summary, this study presented an effective SPI-1 inhibitor, Csn-B, which may have potential in drug development against antibiotic-resistant Salmonella.

  13. Tenarife Island, Canary Island Archipelago, Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Tenarife Island is one of the most volcanically active of the Canary Island archipelago, Atlantic Ocean, just off the NW coast of Africa, (28.5N, 16.5W). The old central caldera, nearly filled in by successive volcanic activity culminating in two stratocones. From those two peaks, a line of smaller cinder cones extend to the point of the island. Extensive gullies dissect the west side of the island and some forests still remain on the east side.

  14. Island Formation: Constructing a Coral Island

    ERIC Educational Resources Information Center

    Austin, Heather; Edd, Amelia

    2009-01-01

    The process of coral island formation is often difficult for middle school students to comprehend. Coral island formation is a dynamic process, and students should have the opportunity to experience this process in a synergistic context. The authors provide instructional guidelines for constructing a coral island. Students play an interactive role…

  15. Vector-borne diseases on Fire Island, New York (Fire Island National Seashore Science Synthesis Paper)

    USGS Publications Warehouse

    Ginsberg, H.S.

    2005-01-01

    This paper discusses eleven tick-borne and five mosquito-borne pathogens that are known to occur at FIlS, or could potentially occur. The potential for future occurrence, and ecological factors that influence occurrence, are assessed for each disease. Lyme disease is the most common vector-borne disease on Fire Island. The Lyme spirochete, Borrelia burgdorferi, is endemic in local tick and wildlife populations. Public education, personal precautions against tick bite, and prompt treatment of early-stage infections can help manage the risk of Lyme disease on Fire Island. The pathogens that cause Human Monocytic Ehrlichiosis and Tularemia have been isolated from ticks or wildlife on Fire Island, and conditions suggest that other tickborne diseases (including Babesiosis, Rocky Mountain Spotted Fever, and Human Granulocytic Ehrlichiosis) might also occur, but these are far less common than Lyme disease, if present. West Nile Virus (WNV) is the primary mosquito- borne human pathogen that is known to occur on Fire Island. Ecological conditions and recent epizootiological events suggest that WNV occurs in foci that can shift from year to year. Therefore, a surveillance program with appropriate responses to increasing epizootic activity can help manage the risk of WNV transmission on Fire Island.

  16. Hawaiian Island Archipelago

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The entire Hawaiian Island Archipelago (21.5N, 158.0W) is seen in this single view. The islands are a favorite international resort and tourist attraction drawing visitors from all over the world to enjoy the tropical climate, year round beaches and lush island flora. Being volcanic in origin, the islands' offer a rugged landscape and on the big island of Hawaii, there is still an occasional volcanic eruption of lava flows and steam vents.

  17. Understanding the sequential activation of Type III and Type VI Secretion Systems in Salmonella typhimurium using Boolean modeling

    PubMed Central

    2013-01-01

    Background Three pathogenicity islands, viz. SPI-1 (Salmonella pathogenicity island 1), SPI-2 (Salmonella pathogenicity island 2) and T6SS (Type VI Secretion System), present in the genome of Salmonella typhimurium have been implicated in the virulence of the pathogen. While the regulation of SPI-1 and SPI-2 (both encoding components of the Type III Secretion System - T3SS) are well understood, T6SS regulation is comparatively less studied. Interestingly, inter-connections among the regulatory elements of these three virulence determinants have also been suggested to be essential for successful infection. However, till date, an integrated view of gene regulation involving the regulators of these three secretion systems and their cross-talk is not available. Results In the current study, relevant regulatory information available from literature have been integrated into a single Boolean network, which portrays the dynamics of T3SS (SPI-1 and SPI-2) and T6SS mediated virulence. Some additional regulatory interactions involving a two-component system response regulator YfhA have also been predicted and included in the Boolean network. These predictions are aimed at deciphering the effects of osmolarity on T6SS regulation, an aspect that has been suggested in earlier studies, but the mechanism of which was hitherto unknown. Simulation of the regulatory network was able to recreate in silico the experimentally observed sequential activation of SPI-1, SPI-2 and T6SS. Conclusions The present study integrates relevant gene regulatory data (from literature and our prediction) into a single network, representing the cross-communication between T3SS (SPI-1 and SPI-2) and T6SS. This holistic view of regulatory interactions is expected to improve the current understanding of pathogenesis of S. typhimurium. PMID:24079299

  18. Common themes in microbial pathogenicity revisited.

    PubMed Central

    Finlay, B B; Falkow, S

    1997-01-01

    Bacterial pathogens employ a number of genetic strategies to cause infection and, occasionally, disease in their hosts. Many of these virulence factors and their regulatory elements can be divided into a smaller number of groups based on the conservation of similar mechanisms. These common themes are found throughout bacterial virulence factors. For example, there are only a few general types of toxins, despite a large number of host targets. Similarly, there are only a few conserved ways to build the bacterial pilus and nonpilus adhesins used by pathogens to adhere to host substrates. Bacterial entry into host cells (invasion) is a complex mechanism. However, several common invasion themes exist in diverse microorganisms. Similarly, once inside a host cell, pathogens have a limited number of ways to ensure their survival, whether remaining within a host vacuole or by escaping into the cytoplasm. Avoidance of the host immune defenses is key to the success of a pathogen. Several common themes again are employed, including antigenic variation, camouflage by binding host molecules, and enzymatic degradation of host immune components. Most virulence factors are found on the bacterial surface or secreted into their immediate environment, yet virulence factors operate through a relatively small number of microbial secretion systems. The expression of bacterial pathogenicity is dependent upon complex regulatory circuits. However, pathogens use only a small number of biochemical families to express distinct functional factors at the appropriate time that causes infection. Finally, virulence factors maintained on mobile genetic elements and pathogenicity islands ensure that new strains of pathogens evolve constantly. Comprehension of these common themes in microbial pathogenicity is critical to the understanding and study of bacterial virulence mechanisms and to the development of new "anti-virulence" agents, which are so desperately needed to replace antibiotics. PMID

  19. From cholera to corals: Viruses as drivers of virulence in a major coral bacterial pathogen

    PubMed Central

    Weynberg, Karen D.; Voolstra, Christian R.; Neave, Matthew J.; Buerger, Patrick; van Oppen, Madeleine J. H.

    2015-01-01

    Disease is an increasing threat to reef-building corals. One of the few identified pathogens of coral disease is the bacterium Vibrio coralliilyticus. In Vibrio cholerae, infection by a bacterial virus (bacteriophage) results in the conversion of non-pathogenic strains to pathogenic strains and this can lead to cholera pandemics. Pathogenicity islands encoded in the V. cholerae genome play an important role in pathogenesis. Here we analyse five whole genome sequences of V. coralliilyticus to examine whether virulence is similarly driven by horizontally acquired elements. We demonstrate that bacteriophage genomes encoding toxin genes with homology to those found in pathogenic V. cholerae are integrated in V. coralliilyticus genomes. Virulence factors located on chromosomal pathogenicity islands also exist in some strains of V. coralliilyticus. The presence of these genetic signatures indicates virulence in V. coralliilyticus is driven by prophages and other horizontally acquired elements. Screening for pathogens of coral disease should target conserved regions in these elements. PMID:26644037

  20. Salmonella SirA is a global regulator of genes mediating enteropathogenesis.

    PubMed

    Ahmer, B M; van Reeuwijk, J; Watson, P R; Wallis, T S; Heffron, F

    1999-02-01

    SirA of Salmonella typhimurium is known to regulate the hilA and prgH genes within Salmonella pathogenicity island 1 (SPI1). To identify more members of the SirA regulon, we screened 10,000 random lacZY fusions (chromosomal MudJ insertions) for regulation by SirA and identified 10 positively regulated fusions. Three fusions were within the SPI1 genes hilA (an SPI1 transcriptional regulator), spaS (a component of the SPI1 type III export apparatus) and sipB (a substrate of the SPI1 export apparatus). Two fusions were within the sopB gene (also known as sigD). sopB is located within SPI5, but encodes a protein that is exported via the SPI1 export apparatus. In addition, five fusions were within genes of unknown function that are located in SPI4. As spaS and sipB were likely to be hilA dependent, we tested all of the fusions (except hilA) for hilA dependence. Surprisingly, we found that all of the fusions require hilA for expression and that plasmid-encoded SirA cannot bypass this requirement. Therefore, SirA regulates hilA, the product of which regulates genes within SPI1, SPI4 and SPI5. Both sirA and hilA mutants are dramatically attenuated in a bovine model of gastroenteritis, but have little or no effect in the mouse model of typhoid fever. This study establishes the SirA/HilA regulatory cascade as the primary regulon controlling enteropathogenic virulence functions in S. typhimurium. Because S. typhimurium causes gastroenteritis in both cattle and humans, we believe that this information may be directly applicable to the human disease.

  1. Using Transcriptional Control To Increase Titers of Secreted Heterologous Proteins by the Type III Secretion System

    PubMed Central

    Metcalf, Kevin J.; Finnerty, Casey; Azam, Anum; Valdivia, Elias

    2014-01-01

    The type III secretion system (T3SS) encoded at the Salmonella pathogenicity island 1 (SPI-1) locus secretes protein directly from the cytosol to the culture media in a concerted, one-step process, bypassing the periplasm. While this approach is attractive for heterologous protein production, product titers are too low for many applications. In addition, the expression of the SPI-1 gene cluster is subject to native regulation, which requires culturing conditions that are not ideal for high-density growth. We used transcriptional control to increase the amount of protein that is secreted into the extracellular space by the T3SS of Salmonella enterica. The controlled expression of the gene encoding SPI-1 transcription factor HilA circumvents the requirement of endogenous induction conditions and allows for synthetic induction of the secretion system. This strategy increases the number of cells that express SPI-1 genes, as measured by promoter activity. In addition, protein secretion titer is sensitive to the time of addition and the concentration of inducer for the protein to be secreted and SPI-1 gene cluster. Overexpression of hilA increases secreted protein titer by >10-fold and enables recovery of up to 28 ± 9 mg/liter of secreted protein from an 8-h culture. We also demonstrate that the protein beta-lactamase is able to adopt an active conformation after secretion, and the increase in secreted titer from hilA overexpression also correlates to increased enzyme activity in the culture supernatant. PMID:25038096

  2. Japan: Shikoku Island

    Atmospheric Science Data Center

    2016-08-24

    ... deploying instruments aboard several ships, aircraft, and island stations in the waters surrounding Japan and Korea. They characterized ... These MISR images, centered just north of Shikoku Island in southwest Japan, were acquired on April 13, 2001 during Terra orbit ...

  3. Barrier Island Hazard Mapping.

    ERIC Educational Resources Information Center

    Pilkey, Orrin H.; Neal, William J.

    1980-01-01

    Describes efforts to evaluate and map the susceptibility of barrier islands to damage from storms, erosion, rising sea levels and other natural phenomena. Presented are criteria for assessing the safety and hazard potential of island developments. (WB)

  4. Hawaiian Islands, Pacific Ocean

    NASA Technical Reports Server (NTRS)

    1983-01-01

    This cloudy view of the Hawaiian Islands (21.0N, 157.5W) demonstrates the phenomena of island water wakes and, to a lesser extent, cloud wakes as well. The islands form an obstruction to the ocean current flow and in effect create an observable turbulence in the water on the backside of the islands. The same effect can be observed in clouds as they leave wind blown wisps or streamers around obstacles in their path.

  5. Canary Island Archipelago

    NASA Technical Reports Server (NTRS)

    1989-01-01

    This nearly vertical view of the Canary Archipelago (28.5N, 16.5W) shows five of the seven islands: Grand Canary, Tenerife, Gomera, Hierro and La Palma. The largest island in view is Tenerife. Island cloud wakes evident in this photo are the result of southerly winds giving rise to cloud banks on the lee side especially on Tenerife which has the highest volcanic peaks. Island water wakes and internal waves are also evident but not as apparent.

  6. Henderson Island, Pacific Ocean

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Henderson Island (24.5S, 128.5W) Pacific Ocean southeast of the Tuamotu Archipelago, is a good example of the many barren islands that but for lack of a source of water could be another lush tropical paradise. The crew of HMS Bounty, in searching for a refuge, sailed past this island but rejected it in favor of nearby Pitcairn Island because of the lack of resources and water.

  7. Arctic ice islands

    SciTech Connect

    Sackinger, W.M.; Jeffries, M.O.; Lu, M.C.; Li, F.C.

    1988-01-01

    The development of offshore oil and gas resources in the Arctic waters of Alaska requires offshore structures which successfully resist the lateral forces due to moving, drifting ice. Ice islands are floating, a tabular icebergs, up to 60 meters thick, of solid ice throughout their thickness. The ice islands are thus regarded as the strongest ice features in the Arctic; fixed offshore structures which can directly withstand the impact of ice islands are possible but in some locations may be so expensive as to make oilfield development uneconomic. The resolution of the ice island problem requires two research steps: (1) calculation of the probability of interaction between an ice island and an offshore structure in a given region; and (2) if the probability if sufficiently large, then the study of possible interactions between ice island and structure, to discover mitigative measures to deal with the moving ice island. The ice island research conducted during the 1983-1988 interval, which is summarized in this report, was concerned with the first step. Monte Carlo simulations of ice island generation and movement suggest that ice island lifetimes range from 0 to 70 years, and that 85% of the lifetimes are less then 35 years. The simulation shows a mean value of 18 ice islands present at any time in the Arctic Ocean, with a 90% probability of less than 30 ice islands. At this time, approximately 34 ice islands are known, from observations, to exist in the Arctic Ocean, not including the 10-meter thick class of ice islands. Return interval plots from the simulation show that coastal zones of the Beaufort and Chukchi Seas, already leased for oil development, have ice island recurrences of 10 to 100 years. This implies that the ice island hazard must be considered thoroughly, and appropriate safety measures adopted, when offshore oil production plans are formulated for the Alaskan Arctic offshore. 132 refs., 161 figs., 17 tabs.

  8. Falkland Islands, UK

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This view of the Falkland Islands (52.0S, 58.5W) was taken with a dual camera mount. Compare this scene with STS048-109-043 to analyze the unique properties of each film type. Seldom seen cloud free, the Falkland Islands lie off the southern coast of Argentina. The cold Falklands Ocean Current keeps the islands chilly, ideal for sheep herding and fishing, the two main industries. Colonies of seals and penguins also thrive on the islands.

  9. Pine Island Glacier

    Atmospheric Science Data Center

    2013-04-16

    article title:  Pine Island Glacier, Antarctica     View ... Imaging SpectroRadiometer (MISR) images of the Pine Island Glacier in western Antarctica was acquired on December 12, 2000 during ... sea ice between the glacier and the open water in Pine Island Bay. To the left of the "icebergs" label are chunks of floating ice. ...

  10. Diomede Islands, Bering Straight

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Diomede Islands consisting of the western island Big Diomede (also known as Imaqliq, Nunarbuk or Ratmanov Island), and the eastern island Little Diomede (also known as Krusenstern Island or Inaliq), are two rocky islands located in the middle of the Bering Strait between Russia and Alaska. The islands are separated by an international border and the International Date Line which is approximately 1.5 km from each island; you can look from Alaska into tomorrow in Russia. At the closest land approach between the United States, which controls Little Diomede, and Russia, which controls Big Diomede, they are 3 km apart. Little Diomede Island constitutes the Alaskan City of Diomede, while Big Diomede Island is Russia's easternmost point. The first European to reach the islands was the Russian explorer Semyon Dezhnev in 1648. The text of the 1867 treaty finalizing the sale of Alaska uses the islands to designate the border between the two nations.

    The image was acquired July 8, 2000, covers an area of 13.5 x 10.8 km, and is located at 65.8 degrees north latitude, 169 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  11. The origin and evolution of human pathogens.

    PubMed

    Groisman, Eduardo A; Casadesús, Josep

    2005-04-01

    What are the genetic origins of human pathogens? An international group of scientists discussed this topic at a workshop that took place in late October 2004 in Baeza (Spain). Focusing primarily on bacterial pathogens, they examined the role that pathogenicity islands and bacteriophages play on determining the virulence properties that distinguish closely related members of a given species, such as host range and tissue specificity. They also discussed an instance in which closely related bacterial species differ in the production of a cell surface modification mediating resistance to an antibiotic as a result of the disparate regulation of homologous genes. In certain pathogens, genes normally carrying out housekeeping functions may adopt new functions, whereas in other organisms, genes that respond to stresses associated with non-host environments are silenced during infection to prevent the expression of products that interfere with the normal colonization process. The adaptive behaviour of certain pathogens relies on gene variation at certain loci that by virtue of containing polymeric repeats in regulatory or coding regions, can generate variants that may or may not express products that modify the cell surface of the organism. The meeting also addressed the properties of ORFan genes, which have no homologues in the sequence databases, as well as the creation of genes de novo by duplication and divergence.

  12. Mechanisms of bacterial pathogenicity

    PubMed Central

    Wilson, J; Schurr, M; LeBlanc, C; Ramamurthy, R; Buchanan, K; Nickerson, C

    2002-01-01

    Pathogenic bacteria utilise a number of mechanisms to cause disease in human hosts. Bacterial pathogens express a wide range of molecules that bind host cell targets to facilitate a variety of different host responses. The molecular strategies used by bacteria to interact with the host can be unique to specific pathogens or conserved across several different species. A key to fighting bacterial disease is the identification and characterisation of all these different strategies. The availability of complete genome sequences for several bacterial pathogens coupled with bioinformatics will lead to significant advances toward this goal. PMID:11930024

  13. The two-component system CpxR/A represses the expression of Salmonella virulence genes by affecting the stability of the transcriptional regulator HilD

    PubMed Central

    De la Cruz, Miguel A.; Pérez-Morales, Deyanira; Palacios, Irene J.; Fernández-Mora, Marcos; Calva, Edmundo; Bustamante, Víctor H.

    2015-01-01

    Salmonella enterica can cause intestinal or systemic infections in humans and animals mainly by the presence of pathogenicity islands SPI-1 and SPI-2, containing 39 and 44 genes, respectively. The AraC-like regulator HilD positively controls the expression of the SPI-1 genes, as well as many other Salmonella virulence genes including those located in SPI-2. A previous report indicates that the two-component system CpxR/A regulates the SPI-1 genes: the absence of the sensor kinase CpxA, but not the absence of its cognate response regulator CpxR, reduces their expression. The presence and absence of cell envelope stress activates kinase and phosphatase activities of CpxA, respectively, which in turn controls the level of phosphorylated CpxR (CpxR-P). In this work, we further define the mechanism for the CpxR/A-mediated regulation of SPI-1 genes. The negative effect exerted by the absence of CpxA on the expression of SPI-1 genes was counteracted by the absence of CpxR or by the absence of the two enzymes, AckA and Pta, which render acetyl-phosphate that phosphorylates CpxR. Furthermore, overexpression of the lipoprotein NlpE, which activates CpxA kinase activity on CpxR, or overexpression of CpxR, repressed the expression of SPI-1 genes. Thus, our results provide several lines of evidence strongly supporting that the absence of CpxA leads to the phosphorylation of CpxR via the AckA/Pta enzymes, which represses both the SPI-1 and SPI-2 genes. Additionally, we show that in the absence of the Lon protease, which degrades HilD, the CpxR-P-mediated repression of the SPI-1 genes is mostly lost; moreover, we demonstrate that CpxR-P negatively affects the stability of HilD and thus decreases the expression of HilD-target genes, such as hilD itself and hilA, located in SPI-1. Our data further expand the insight on the different regulatory pathways for gene expression involving CpxR/A and on the complex regulatory network governing virulence in Salmonella. PMID:26300871

  14. BACTERIAL WATERBORNE PATHOGENS

    EPA Science Inventory

    Bacterial pathogens are examples of classical etiological agents of waterborne disease. While these agents no longer serve as major threats to U.S. water supplies, they are still important pathogens in areas with substandard sanitation and poor water treatment facilities. In th...

  15. Plant pathogen resistance

    DOEpatents

    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.

  16. Plant pathogen resistance

    SciTech Connect

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

    2015-10-20

    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.

  17. Emerging foodborne pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The emergence of new foodborne pathogens is due to a number of factors. An important factor is the globalization of the food supply with the possibility of the introduction of foodborne pathogens from other countries. Animal husbandry, food production, food processing, and food distribution system...

  18. Ober's Island, One of the Review Islands on Rainy Lake, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Ober's Island, One of the Review Islands on Rainy Lake, bounded on the south by The Hawk Island and on the north by The Crow Island. These islands are located seven miles east of Ranier, Minnesota, three miles west of Voyageur National Park, and one mile south of the international border of the United States of America and Canada. The legal description of Mallard Island is Lot 6, Section 19, T-17-N, R-22-W, Koochiching County, Minnesota, Ranier, Koochiching County, MN

  19. Hydrologic data for Block Island, Rhode Island

    USGS Publications Warehouse

    Burns, Emily

    1993-01-01

    This report was compiled as part of a study to assess the hydrogeology and the quality and quantity of fresh ground water on Block Island, Rhode Island. Hydrologic data were collected on Block Island during 1988-91. The data are pre- sented in illustrations and tables. Data collec- ted include precipitation, surfae-water, ground- water, lithologic, and well-construction and dis- charge information. Precipitation data include total monthly precipitation values from 11 rain gages and water-quality analyses of 14 precipi- tation samples from one station. Surface-water data include water-level measurements at 12 ponds, water-quality data for five ponds, and field specific-conductance measurements at 56 surface- water sites (streams, ponds, and springs). Ground- water data include water-level measurements at 159 wells, water-quality data at 150 wells, and field specific-conductance data at 52 wells. Lithologic logs for 375 wells and test borings, and construc- tion and location data for 570 wells, springs, and test borings are included. In addition, the data set contains data on water quality of water samples, collected by the Rhode Island Department of Health during 1976-91, from Fresh and Sands Ponds and from wells at the Block Island Water Company well field north of Sands Pond.

  20. Pine Island Bay

    Atmospheric Science Data Center

    2013-04-16

    ... article title:  Birth of a Large Iceberg in Pine Island Bay, Antarctica     View ... iceberg (42 kilometers x 17 kilometers) broke off Pine Island Glacier, West Antarctica (75°S latitude, 102°W longitude) sometime ...

  1. Island Natural Science School.

    ERIC Educational Resources Information Center

    Toronto Board of Education (Ontario).

    Prepared for students in grade six attending the Island Natural Science School, Toronto, Ontario, Canada, this booklet offers information and suggests activities in the areas of ecology, conservation, natural resources, and outdoor recreation. Introductory material describes island lore, its formation and significant features, followed by units of…

  2. Back to Treasure Island

    ERIC Educational Resources Information Center

    Shriki, Atara

    2011-01-01

    In this article, the author presents the Treasure Island problem and some inquiry activities derived from the problem. Trying to find where pirates buried a treasure leads to a surprising answer, multiple solutions, and a discussion of problem solving. The Treasure Island problem is an example of an inquiry activity that can be implemented in…

  3. Islands in a Storm.

    ERIC Educational Resources Information Center

    Vail, Kathleen

    1995-01-01

    Smith Island in the Chesapeake Bay is actually a group of three islands: Ewell, Rhodes Point, and Tylerton. Dwindling enrollment jeopardizes the community's two schools that contain grades one through seven. The school board believes they can give the sixth and seventh graders at Ewell and Tylerton a better education on the mainland. (MLF)

  4. Basaltic island sand provenance

    SciTech Connect

    Marsaglia, K.M. . Dept. of Geological Sciences)

    1992-01-01

    The Hawaiian Islands are an ideal location to study basaltic sand provenance in that they are a series of progressively older basaltic shield volcanoes with arid to humid microclimates. Sixty-two sand samples were collected from beaches on the islands of Hawaii, Maui, Oahu and Kauai and petrographically analyzed. The major sand components are calcareous bioclasts, volcanic lithic fragments, and monomineralic grains of dense minerals and plagioclase. Proportions of these components vary from island to island, with bioclastic end members being more prevalent on older islands exhibiting well-developed fringing reef systems and volcanic end members more prevalent on younger, volcanically active islands. Climatic variations across the island of Hawaii are reflected in the percentage of weathered detritus, which is greater on the wetter, northern side of the island. The groundmass of glassy, basaltic lithics is predominantly black tachylite, with lesser brown sideromelane; microlitic and lathwork textures are more common than holohyaline vitric textures. Other common basaltic volcanic lithic fragments are holocrystalline aggregates of silt-sized pyroxene or olivine, opaque minerals and plagioclase. Sands derived from alkalic lavas are texturally and compositionally indistinguishable from sands derived from tholeiitic lavas. Although Hawaiian basaltic sands overlap in composition with magmatic arc-derived sands in terms of their relative QFL, QmPK and LmLvLs percentages, they are dissimilar in that they lack felsic components and are more enriched in lathwork volcanic lithic fragments, holocrystalline volcanic lithic fragments, and dense minerals.

  5. Marine and Island Ecology.

    ERIC Educational Resources Information Center

    Stephens, Lawrence J.; And Others

    1988-01-01

    Describes an ecology course which provides students with an opportunity to observe aquatic and terrestrial life in the Bahamas. States that students learn scientific methodology by measuring physical and chemical aspects of the island habitats. Provides information on the island, course description and objectives, transportation, facilities, and…

  6. Pathogenicity of entamoeba histolytica.

    PubMed

    Kagan, I G

    1975-01-01

    The pathogenicity of Entamoeba histolytica is discussed from an immunologic point of view. The evidence that there is some "trigger" mechanism which converts a commensal dwelling organism into a tissue invasive pathogen is rejected as inadequate. The number of liver abscess cases in comparison with the number of intestinal amebic infections in a population is so low that this in itself suggests that tissue invasion is a rare event in the life history of the ameba. A review is made of the experimental evidence that some type of sensitization is necessary before ameba can invade tissue. In postulating an immunologic basis for the pathogenicity of ameba, a parallel between the behavior of malignant cells in the body and an amebic infection in the gut is made. An appealing hypothesis which deserves further research effort is that an altered immune response is the basis for the pathogenic mechanism in the host. PMID:171223

  7. Ober's Island: The Mallard Ober's Island, One of the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Ober's Island: The Mallard - Ober's Island, One of the Review Islands on Rainy Lake, bounded on the south by The Hawk Island and on the north by The Crow Island. These islands are located seven miles east of Ranier, Minnesota, three miles west of Voyageur National Park, and one mile south of the international border of the United States of America and Canada. The legal description of Mallard Island is Lot 6, Section 19, T-17-N, R-22-W, Koochiching County, Minnesota, Ranier, Koochiching County, MN

  8. Prevalence of Borrelia burgdorferi and Babesia microti in mice on islands inhabited by white-tailed deer.

    PubMed Central

    Anderson, J F; Johnson, R C; Magnarelli, L A; Hyde, F W; Myers, J E

    1987-01-01

    Borrelia burgdorferi and Babesia microti were isolated from 35 of 51 white-footed mice (Peromyscus leucopus) and meadow voles (Microtus pennsylvanicus) captured on two Narragansett Bay, R.I., islands inhabited by deer, the principal host for the adult stages of the vector tick, Ixodes dammini. Immature ticks parasitized mice from both islands. From 105 mice captured on four other islands not inhabited by deer neither pathogen was isolated, nor were I. dammini found. PMID:3555339

  9. Cognitive Constraints and Island Effects

    ERIC Educational Resources Information Center

    Hofmeister, Philip; Sag, Ivan A.

    2010-01-01

    Competence-based theories of island effects play a central role in generative grammar, yet the graded nature of many syntactic islands has never been properly accounted for. Categorical syntactic accounts of island effects have persisted in spite of a wealth of data suggesting that island effects are not categorical in nature and that…

  10. Stomata and pathogens

    PubMed Central

    Gudesblat, Gustavo E; Torres, Pablo S

    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 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. PMID:20514224

  11. Lost island found

    NASA Astrophysics Data System (ADS)

    An abandoned ll-by-5-km kidney-shaped chunk of freshwater ice, used as a research station for 25 years, was rediscovered after the National Oceanic and Atmospheric Administration (NOAA) lost track of the island for 6 months. The recent find may foreshadow another loss, however: The island is drifting through the Greenland Sea and into the North Atlantic where it should melt within several months and d u m p its cargo of oil drums, equipment, and a wrecked plane into the ocean.Known as Fletcher's Ice Island—after Joseph O. Fletcher, a member of the first team of researchers to inhabit the island and a recently retired NOAA climate researcher—the ice chunk has already melted to a third of its original 49 m thickness. A pilot flying over the area to measure annual pollution buildup in the Arctic located the drifting island 242 km from the North Pole near the International Date Line.

  12. Island Watershed Activity.

    ERIC Educational Resources Information Center

    Benson, Rod

    2003-01-01

    Describes a 90-minute "Island Watershed" activity to help earth science students understand the concept of the water cycle. Introduces a surface waters unit appropriate for students in grades 7-10. Includes watershed project guidelines. (Author/KHR)

  13. Small islands adrift

    NASA Astrophysics Data System (ADS)

    Petherick, Anna

    2015-07-01

    With the charismatic former president of the Maldives, Mohamed Nasheed, behind bars on a widely derided terrorism charge, Anna Petherick asks whether small island states can really make themselves heard in Paris.

  14. Islands, resettlement and adaptation

    NASA Astrophysics Data System (ADS)

    Barnett, Jon; O'Neill, Saffron J.

    2012-01-01

    Resettlement of people living on islands in anticipation of climate impacts risks maladaptation, but some forms of population movement carry fewer risks and larger rewards in terms of adapting to climate change.

  15. Melville Island, Australia

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Melville Island, just off the coast of Darwin, Northern Territory, Australia (11.5S, 131.0E) is a sparsely inhabited tropical island with heavy woodland concentrations. The widespread and prominant smoke plumes were most likely set to renew pasture under open canopy woodland. Soil erosion is almost non- existant as can be seen by the clear and clean river flow. The offshore sediments are coastal current borne deposits from King Sound to the west.

  16. Bioterrorism: pathogens as weapons.

    PubMed

    Anderson, Peter D; Bokor, Gyula

    2012-10-01

    Biowarfare has been used for centuries. The use of biological weapons in terrorism remains a threat. Biological weapons include infectious agents (pathogens) and toxins. The most devastating bioterrorism scenario would be the airborne dispersal of pathogens over a concentrated population area. Characteristics that make a specific pathogen a high-risk for bioterrorism include a low infective dose, ability to be aerosolized, high contagiousness, and survival in a variety of environmental conditions. The most dangerous potential bioterrorism agents include the microorganisms that produce anthrax, plague, tularemia, and smallpox. Other diseases of interest to bioterrorism include brucellosis, glanders, melioidosis, Q fever, and viral encephalitis. Food safety and water safety threats are another area of concern.

  17. Bioterrorism: pathogens as weapons.

    PubMed

    Anderson, Peter D; Bokor, Gyula

    2012-10-01

    Biowarfare has been used for centuries. The use of biological weapons in terrorism remains a threat. Biological weapons include infectious agents (pathogens) and toxins. The most devastating bioterrorism scenario would be the airborne dispersal of pathogens over a concentrated population area. Characteristics that make a specific pathogen a high-risk for bioterrorism include a low infective dose, ability to be aerosolized, high contagiousness, and survival in a variety of environmental conditions. The most dangerous potential bioterrorism agents include the microorganisms that produce anthrax, plague, tularemia, and smallpox. Other diseases of interest to bioterrorism include brucellosis, glanders, melioidosis, Q fever, and viral encephalitis. Food safety and water safety threats are another area of concern. PMID:23011963

  18. Highly pathogenic avian influenza.

    PubMed

    Swayne, D E; Suarez, D L

    2000-08-01

    Highly pathogenic (HP) avian influenza (AI) (HPAI) is an extremely contagious, multi-organ systemic disease of poultry leading to high mortality, and caused by some H5 and H7 subtypes of type A influenza virus, family Orthomyxoviridae. However, most AI virus strains are mildly pathogenic (MP) and produce either subclinical infections or respiratory and/or reproductive diseases in a variety of domestic and wild bird species. Highly pathogenic avian influenza is a List A disease of the Office International des Epizooties, while MPAI is neither a List A nor List B disease. Eighteen outbreaks of HPAI have been documented since the identification of AI virus as the cause of fowl plague in 1955. Mildly pathogenic avian influenza viruses are maintained in wild aquatic bird reservoirs, occasionally crossing over to domestic poultry and causing outbreaks of mild disease. Highly pathogenic avian influenza viruses do not have a recognised wild bird reservoir, but can occasionally be isolated from wild birds during outbreaks in domestic poultry. Highly pathogenic avian influenza viruses have been documented to arise from MPAI viruses through mutations in the haemagglutinin surface protein. Prevention of exposure to the virus and eradication are the accepted methods for dealing with HPAI. Control programmes, which imply allowing a low incidence of infection, are not an acceptable method for managing HPAI, but have been used during some outbreaks of MPAI. The components of a strategy to deal with MPAI or HPAI include surveillance and diagnosis, biosecurity, education, quarantine and depopulation. Vaccination has been used in some control and eradication programmes for AI.

  19. Bloodborne Pathogens Program

    NASA Technical Reports Server (NTRS)

    Blasdell, Sharon

    1993-01-01

    The final rule on the Occupational Exposure to Bloodborne Pathogens was published in the Federal Register on Dec. 6, 1991. This Standard, 29 CFR Part 1910.130, is expected to prevent 8,900 hepatitis B infections and nearly 200 deaths a year in healthcare workers in the U.S. The Occupational Medicine and Environmental Health Services at KSC has been planning to implement this standard for several years. Various aspects of this standard and its Bloodborne Pathogens Program at KSC are discussed.

  20. Waterborne Pathogens: The Protozoans.

    PubMed

    Moss, Joseph Anthony

    2016-09-01

    Waterborne diseases associated with polluted recreational and potable waters have been documented for more than a century. Key microbial protozoan parasites, such as Cryptosporidium and Giardia, are causative agents for gastrointestinal disease worldwide. Although not a first-line diagnostic approach for these diseases, medical imaging, such as radiography, computed tomography, magnetic resonance imaging, ultrasonography, and nuclear medicine technologies, can be used to evaluate patients with long-term effects. This article describes protozoan pathogens that affect human health, treatment of common waterborne pathogen-related diseases, and associated medical imaging. PMID:27601690

  1. Genomic and Phenotypic Analyses Reveal the Emergence of an Atypical Salmonella enterica Serovar Senftenberg Variant in China.

    PubMed

    Abd El Ghany, Moataz; Shi, Xiaolu; Li, Yinghui; Ansari, Hifzur R; Hill-Cawthorne, Grant A; Ho, Y S; Naeem, Raeece; Pickard, Derek; Klena, John D; Xu, Xuebing; Pain, Arnab; Hu, Qinghua

    2016-08-01

    Human infections with Salmonella enterica subspecies enterica serovar Senftenberg are often associated with exposure to poultry flocks, farm environments, or contaminated food. The recent emergence of multidrug-resistant isolates has raised public health concerns. In this study, comparative genomics and phenotypic analysis were used to characterize 14 Salmonella Senftenberg clinical isolates recovered from multiple outbreaks in Shenzhen and Shanghai, China, between 2002 and 2011. Single-nucleotide polymorphism analyses identified two phylogenetically distinct clades of S Senftenberg, designated SC1 and SC2, harboring variations in Salmonella pathogenicity island 1 (SPI-1) and SPI-2 and exhibiting distinct biochemical and phenotypic signatures. Although the two variants shared the same serotype, the SC2 isolates of sequence type 14 (ST14) harbored intact SPI-1 and -2 and hence were characterized by possessing efficient invasion capabilities. In contrast, the SC1 isolates had structural deletion patterns in both SPI-1 and -2 that correlated with an impaired capacity to invade cultured human cells and also the year of their isolation. These atypical SC1 isolates also lacked the capacity to produce hydrogen sulfide. These findings highlight the emergence of atypical Salmonella Senftenberg variants in China and provide genetic validation that variants lacking SPI-1 and regions of SPI-2, which leads to impaired invasion capacity, can still cause clinical disease. These data have identified an emerging public health concern and highlight the need to strengthen surveillance to detect the prevalence and transmission of nontyphoidal Salmonella species.

  2. PATHOGEN EQUIVALENCY COMMITTEE (PEC)

    EPA Science Inventory

    The U.S. Environmental Protection Agency created the PEC in 1985 to make recommendations to EPA and State managers on the equivalency of unproven sewage sludge disinfection technologies/processes to either a Process to Significantly Reduce Pathogens (PSRP) or a Process to Further...

  3. DISINFECTION OF EMERGING PATHOGENS

    EPA Science Inventory

    There is a growing awareness of the need to control waterborne microbial pathogens. This presentation will concentate on the role of chemical inactivation, using chlorine, chloramines and ozone as a means of controlling bacterial and protozoan species. Information will be present...

  4. Leafhopper viral pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four newly discovered viral pathogens in leafhopper vectors of Pierce’s disease of grapes, have been shown to replicate in sharpshooter leafhoppers; the glassy-winged sharpshooter, GWSS, Homalodisca vitripennis, and Oncometopia nigricans (Hemiptera: Cicadellidae). The viruses were classified as memb...

  5. Bacterial genomes: evolution of pathogenicity.

    PubMed

    Arnold, Dawn L; Jackson, Robert W

    2011-08-01

    Bacterial pathogens continue to pose a major threat to economically important plant resources. Disease outbreaks can occur through rapid evolution of a pathogen to overcome host defences. The advent of genome sequencing, especially next-generation technologies, has seen a revolution in the study of plant pathogen evolution over the past five years. This review highlights recent developments in understanding bacterial plant pathogen evolution, enabled by genomics and specifically focusing on type III protein effectors. The genotypic changes and mechanisms involved in pathogen evolution are now much better understood. However, there is still much to be learned about the drivers of pathogen evolution, both in terms of plant resistance and bacterial lifestyle.

  6. Heron Island, Australia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Heron Island is located at the sourthern end of Australia's 2,050 km-long Great Barrier Reef. Surrounded by coral reef and home to over 1000 species of fish, scuba divers and scientists alike are drawn to the island's resort and research station. The true-color image above was taken by Space Imaging's Ikonos satellite with a resolution of 4 meters per pixel-high enough to see individual boats tied up at the small marina. The narrow channel leading from the marina to the ocean was blasted and dredged decades ago, before the island became a national park. Since then the Australian government has implemented conservation measures, such as limiting the number of tourists and removing or recycling, instead of incinerating, all trash. One of the applications of remote sensing data from Ikonos is environmental monitoring, including studies of coral reef health. For more information about the island, read Heron Island. Image by Robert Simmon, based on data copyright Space Imaging

  7. Habitat and environment of islands: primary and supplemental island sets

    USGS Publications Warehouse

    Matalas, Nicholas C.; Grossling, Bernardo F.

    2002-01-01

    The original intent of the study was to develop a first-order synopsis of island hydrology with an integrated geologic basis on a global scale. As the study progressed, the aim was broadened to provide a framework for subsequent assessments on large regional or global scales of island resources and impacts on those resources that are derived from global changes. Fundamental to the study was the development of a comprehensive framework?a wide range of parameters that describe a set of 'saltwater' islands sufficiently large to Characterize the spatial distribution of the world?s islands; Account for all major archipelagos; Account for almost all oceanically isolated islands, and Account collectively for a very large proportion of the total area of the world?s islands whereby additional islands would only marginally contribute to the representativeness and accountability of the island set. The comprehensive framework, which is referred to as the ?Primary Island Set,? is built on 122 parameters that describe 1,000 islands. To complement the investigations based on the Primary Island Set, two supplemental island sets, Set A?Other Islands (not in the Primary Island Set) and Set B?Lagoonal Atolls, are included in the study. The Primary Island Set, together with the Supplemental Island Sets A and B, provides a framework that can be used in various scientific disciplines for their island-based studies on broad regional or global scales. The study uses an informal, coherent, geophysical organization of the islands that belong to the three island sets. The organization is in the form of a global island chain, which is a particular sequential ordering of the islands referred to as the 'Alisida.' The Alisida was developed through a trial-and-error procedure by seeking to strike a balance between 'minimizing the length of the global chain' and 'maximizing the chain?s geophysical coherence.' The fact that an objective function cannot be minimized and maximized simultaneously

  8. Maintenance of biodiversity on islands.

    PubMed

    Chisholm, Ryan A; Fung, Tak; Chimalakonda, Deepthi; O'Dwyer, James P

    2016-04-27

    MacArthur and Wilson's theory of island biogeography predicts that island species richness should increase with island area. This prediction generally holds among large islands, but among small islands species richness often varies independently of island area, producing the so-called 'small-island effect' and an overall biphasic species-area relationship (SAR). Here, we develop a unified theory that explains the biphasic island SAR. Our theory's key postulate is that as island area increases, the total number of immigrants increases faster than niche diversity. A parsimonious mechanistic model approximating these processes reproduces a biphasic SAR and provides excellent fits to 100 archipelago datasets. In the light of our theory, the biphasic island SAR can be interpreted as arising from a transition from a niche-structured regime on small islands to a colonization-extinction balance regime on large islands. The first regime is characteristic of classic deterministic niche theories; the second regime is characteristic of stochastic theories including the theory of island biogeography and neutral theory. The data furthermore confirm our theory's key prediction that the transition between the two SAR regimes should occur at smaller areas, where immigration is stronger (i.e. for taxa that are better dispersers and for archipelagos that are less isolated).

  9. Maintenance of biodiversity on islands.

    PubMed

    Chisholm, Ryan A; Fung, Tak; Chimalakonda, Deepthi; O'Dwyer, James P

    2016-04-27

    MacArthur and Wilson's theory of island biogeography predicts that island species richness should increase with island area. This prediction generally holds among large islands, but among small islands species richness often varies independently of island area, producing the so-called 'small-island effect' and an overall biphasic species-area relationship (SAR). Here, we develop a unified theory that explains the biphasic island SAR. Our theory's key postulate is that as island area increases, the total number of immigrants increases faster than niche diversity. A parsimonious mechanistic model approximating these processes reproduces a biphasic SAR and provides excellent fits to 100 archipelago datasets. In the light of our theory, the biphasic island SAR can be interpreted as arising from a transition from a niche-structured regime on small islands to a colonization-extinction balance regime on large islands. The first regime is characteristic of classic deterministic niche theories; the second regime is characteristic of stochastic theories including the theory of island biogeography and neutral theory. The data furthermore confirm our theory's key prediction that the transition between the two SAR regimes should occur at smaller areas, where immigration is stronger (i.e. for taxa that are better dispersers and for archipelagos that are less isolated). PMID:27122558

  10. Genomic Islands of Uropathogenic Escherichia coli Contribute to Virulence▿ †

    PubMed Central

    Lloyd, Amanda L.; Henderson, Tiffany A.; Vigil, Patrick D.; Mobley, Harry L. T.

    2009-01-01

    Uropathogenic Escherichia coli (UPEC) strain CFT073 contains 13 large genomic islands ranging in size from 32 kb to 123 kb. Eleven of these genomic islands were individually deleted from the genome, and nine isogenic mutants were tested for their ability to colonize the CBA/J mouse model of ascending urinary tract infection. Three genomic island mutants (ΔPAI-aspV, ΔPAI-metV, and ΔPAI-asnT) were significantly outcompeted by wild-type CFT073 in the bladders and/or kidneys following transurethral cochallenge (P ≤ 0.0139). The PAI-metV mutant also showed significant attenuation in the ability to independently colonize the kidneys (P = 0.0011). Specific genes within these islands contributed to the observed phenotype, including a previously uncharacterized iron acquisition cluster, fbpABCD (c0294 to c0297 [c0294-97]), autotransporter, picU (c0350), and RTX family exoprotein, tosA (c0363) in the PAI-aspV island. The double deletion mutant with deletions in both copies of the fbp iron acquisition operon (Δc0294-97 Δc2518-15) was significantly outcompeted by wild-type CFT073 in cochallenge. Strains with mutations in a type VI secretion system within the PAI-metV island did not show attenuation. The attenuation of the PAI-metV island was localized to genes c3405-10, encoding a putative phosphotransferase transport system, which is common to UPEC and avian pathogenic E. coli strains but absent from E. coli K-12. We have shown that, in addition to encoding virulence genes, genomic islands contribute to the overall fitness of UPEC strain CFT073 in vivo. PMID:19329634

  11. Lethality of First Contact Dysentery Epidemics on Pacific Islands.

    PubMed

    Shanks, G Dennis

    2016-08-01

    Infectious diseases depopulated many isolated Pacific islands when they were first exposed to global pathogen circulation from the 18th century. Although the mortality was great, the lack of medical observers makes determination of what happened during these historical epidemics largely speculative. Bacillary dysentery caused by Shigella is the most likely infection causing some of the most lethal island epidemics. The fragmentary historical record is reviewed to gain insight into the possible causes of the extreme lethality that was observed during first-contact epidemics in the Pacific. Immune aspects of the early dysentery epidemics and postmeasles infection resulting in subacute inflammatory enteric disease suggest that epidemiologic isolation was the major lethality risk factor on Pacific islands in the 19th century. Other possible risk factors include human leukocyte antigen homogeneity from a founder effect and pathogen-induced derangement of immune tolerance to gut flora. If this analysis is correct, then Pacific islands are currently at no greater risk of emerging disease epidemics than other developing countries despite their dark history. PMID:27185765

  12. Lethality of First Contact Dysentery Epidemics on Pacific Islands.

    PubMed

    Shanks, G Dennis

    2016-08-01

    Infectious diseases depopulated many isolated Pacific islands when they were first exposed to global pathogen circulation from the 18th century. Although the mortality was great, the lack of medical observers makes determination of what happened during these historical epidemics largely speculative. Bacillary dysentery caused by Shigella is the most likely infection causing some of the most lethal island epidemics. The fragmentary historical record is reviewed to gain insight into the possible causes of the extreme lethality that was observed during first-contact epidemics in the Pacific. Immune aspects of the early dysentery epidemics and postmeasles infection resulting in subacute inflammatory enteric disease suggest that epidemiologic isolation was the major lethality risk factor on Pacific islands in the 19th century. Other possible risk factors include human leukocyte antigen homogeneity from a founder effect and pathogen-induced derangement of immune tolerance to gut flora. If this analysis is correct, then Pacific islands are currently at no greater risk of emerging disease epidemics than other developing countries despite their dark history.

  13. Archaeoastronomy of Easter Island

    NASA Astrophysics Data System (ADS)

    Edwards, Edmundo

    Astronomer priests or "skywatchers" on Easter Island lived in stone towers that were used as observatories and built stone markers in the periphery that indicated the heliacal rising of certain stars that served to indicate the arrival of marine birds, turtles, the offshore fishing season, and times for planting and harvest. Petroglyphs related to such sites depict outriggers, fishhooks, pelagic fish, and turtles and supposedly represented a star map. In this chapter, we analyze a set of such skywatchers dwellings, and stone markers located upon the North coast of Easter Island that have astronomic orientations, its related petroglyphs, and the relations between these directions with their yearly activities and their ritual calendar.

  14. Island custom blocking technique

    SciTech Connect

    Carabetta, R.J. )

    1988-03-01

    The technique of Island blocking is being used more frequently since the advent of our new head and neck blocking techniques and the implementation of a newly devised lung protocol. The system presented affords the mould room personnel a quick and accurate means of island block fabrication without the constant remeasuring or subtle shifting to approximate correct placement. The cookie cutter is easily implemented into any department's existing block cutting techniques. The device is easily and inexpensively made either in a machine shop or acquired by contacting the author.

  15. Long Island Solar Farm

    SciTech Connect

    Anders, R.

    2013-05-01

    The Long Island Solar Farm (LISF) is a remarkable success story, whereby very different interest groups found a way to capitalize on unusual circumstances to develop a mutually beneficial source of renewable energy. The uniqueness of the circumstances that were necessary to develop the Long Island Solar Farm make it very difficult to replicate. The project is, however, an unparalleled resource for solar energy research, which will greatly inform large-scale PV solar development in the East. Lastly, the LISF is a superb model for the process by which the project developed and the innovation and leadership shown by the different players.

  16. Sakhalin Island terrain intelligence

    USGS Publications Warehouse

    ,

    1943-01-01

    This folio of maps and explanatory tables outlines the principal terrain features of Sakhalin Island. Each map and table is devoted to a specialized set of problems; together they cover the subjects of terrain appreciation, climate, rivers, water supply, construction materials, suitability for roads, suitability for airfields, fuels and other mineral resources, and geology. In most cases, the map of the island is divided into two parts: N. of latitude 50° N., Russian Sakhalin, and south of latitude 50° N., Japanese Sakhalin or Karafuto. These maps and data were compiled by the United States Geological Survey during the period from March to September, 1943.

  17. Acanthamoeba genotypes T2, T4, and T11 in soil sources from El Hierro island, Canary Islands, Spain.

    PubMed

    Reyes-Batlle, María; Zamora-Herrera, Jonadab; Vargas-Mesa, Alejandro; Valerón-Tejera, Marco Antonio; Wagner, Carolina; Martín-Navarro, Carmen Ma; López-Arencibia, Atteneri; Sifaoui, Ines; Martínez-Carretero, Enrique; Valladares, Basilio; Piñero, José E; Lorenzo-Morales, Jacob

    2016-08-01

    The genus Acanthamoeba includes pathogenic strains which are causative agents of keratitis and encephalitis that often may end fatal in humans and other animals. In the present study, forty soil samples were collected in the island of El Hierro, Canary Islands, Spain, and checked for the presence of Acanthamoeba. Samples were cultivated onto 2 % non-nutrient agar plates seeded with a layer of heat killed Escherichia coli. Amplification by PCR and sequencing of the DF3 region of the 18S rDNA of Acanthamoeba was carried out in order to confirm morphological identification of the amoebae. Furthermore, Acanthamoeba spp. was isolated from 47.5 % of soil samples. Moreover, genotypes T2, T4, and T11 were identified in these samples. To the best of our knowledge, this is the first study to establish genotypes T2, T4, and T11 in soil sources from El Hierro island.

  18. Multiplex detection of agricultural pathogens

    DOEpatents

    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.

  19. Multiplex detection of agricultural pathogens

    DOEpatents

    McBride, Mary Teresa; Slezak, Thomas Richard; Messenger, Sharon Lee

    2010-09-14

    Described are kits and methods useful for detection of seven agricultural pathogens (BPSV; BHV; BVD; FMDV; BTV; SVD; and VESV) in a sample. Genomic sequence information from 7 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 to successfully identify the presence or absence of pathogens in a sample.

  20. Opportunistic Pathogenic Yeasts

    NASA Astrophysics Data System (ADS)

    Banerjee, Uma

    Advances in medical research, made during the last few decades, have improved the prophylactic, diagnostic and therapeutic capabilities for variety of infections/diseases. However, many of the prophylactic and therapeutic procedures have been seen in many instances to exact a price of host-vulnerability to an expanding group of opportunistic pathogens and yeasts are one of the important members in it. Fortunately amongst the vast majority of yeasts present in nature only few are considered to have the capability to cause infections when certain opportunities predisposes and these are termed as ‘opportunistic pathogenic yeasts.’ However, the term ‘pathogenic’ is quite tricky, as it depends of various factors of the host, the ‘bug’ and the environment to manifest the clinical infection. The borderline is expanding. In the present century with unprecedented increase in number of immune-compromised host in various disciplines of health care settings, where any yeast, which has the capability to grow at 37 ° C (normal body temperature of human), can be pathogenic and cause infection in particular situation

  1. Extraintestinal pathogenic Escherichia coli.

    PubMed

    Smith, James L; Fratamico, Pina M; Gunther, Nereus W

    2007-01-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) possesses virulence traits that allow it to invade, colonize, and induce disease in bodily sites outside of the gastrointestinal tract. Human diseases caused by ExPEC include urinary tract infections, neonatal meningitis, sepsis, pneumonia, surgical site infections, as well as infections in other extraintestinal locations. ExPEC-induced diseases represent a large burden in terms of medical costs and productivity losses. In addition to human illnesses, ExPEC strains also cause extraintestinal infections in domestic animals and pets. A commonality of virulence factors has been demonstrated between human and animal ExPEC, suggesting that the organisms are zoonotic pathogens. ExPEC strains have been isolated from food products, in particular from raw meats and poultry, indicating that these organisms potentially represent a new class of foodborne pathogens. This review discusses various aspects of ExPEC, including its presence in food products, in animals used for food or as companion pets; the diseases ExPEC can cause; and the virulence factors and virulence mechanisms that cause disease.

  2. Population Bottlenecks and Pathogen Extinction: "Make This Everyone's Mission to Mars, Including Yours".

    PubMed

    Policicchio, Benjamin B; Pandrea, Ivona; Apetrei, Cristian

    2015-08-01

    Kapusinszky et al. (J Virol 89:8152-8161, 2015, http://dx.doi.org/10.1128/JVI.00671-15) report that host population bottlenecks may result in pathogen extinction, which provides a compelling argument for an alternative approach to vaccination for the control of virus spread. By comparing the prevalence levels of three viral pathogens in two populations of African green monkeys (AGMs) (Chlorocebus sabaeus) from Africa and two Caribbean Islands, they convincingly show that a major host bottleneck resulted in the eradication of select pathogens from a given host.

  3. Population Bottlenecks and Pathogen Extinction: "Make This Everyone's Mission to Mars, Including Yours".

    PubMed

    Policicchio, Benjamin B; Pandrea, Ivona; Apetrei, Cristian

    2015-08-01

    Kapusinszky et al. (J Virol 89:8152-8161, 2015, http://dx.doi.org/10.1128/JVI.00671-15) report that host population bottlenecks may result in pathogen extinction, which provides a compelling argument for an alternative approach to vaccination for the control of virus spread. By comparing the prevalence levels of three viral pathogens in two populations of African green monkeys (AGMs) (Chlorocebus sabaeus) from Africa and two Caribbean Islands, they convincingly show that a major host bottleneck resulted in the eradication of select pathogens from a given host. PMID:26018162

  4. Kiritimati, Kiribati (Christmas Island)

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Pronounced 'Ki-ris-mas,' Kiritimati Island has a large infilled lagoon that gives it the largest land area (125 square miles, 321 square km) of any atoll in the world. Captain Cook named the atoll Christmas Island when he arrived on Christmas Eve in 1777. Used for nuclear testing in the 1950s and 1960s, the island is now valued for its marine and wildlife resources. It is particularly important as a seabird nesting site-with an estimated 6 million birds using or breeding on the island, including several million Sooty Terns. Rainfall on Kiritimati is linked to El Nino patterns, with long droughts experienced between the wetter El Nino years. This image is based on a mosaic of four digital photographs taken on 16 January 2002 from the Space Station Alpha as part of the Crew Earth Observations Project. The underlying data have 10 meter spatial resolution. Coral reefs are one of the areas selected as a scientific theme for this project (see also the recent Earth Observatory article, Mapping the Decline of Coral Reefs. The mosaic, based on images ISS004-ESC-6249 to 6252, was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  5. Hawaii's Sugar Islands.

    ERIC Educational Resources Information Center

    Hawaiian Sugar Planters' Association, Aiea, HI.

    A warm and sunny subtropical climate helps make Hawaii an important sugar producer. History records that sugarcane was already present when Captain James Cook discovered the islands in 1778, and that the first successful sugarcane plantation was started in 1835 by Ladd and Company at Koloa. The first recorded export of Hawaiian sugar was in 1837,…

  6. Bouvet Island near Antarctica

    Atmospheric Science Data Center

    2013-04-16

    ... supplies were discovered on the island in 1964, but their origin could not be determined. Seals in the area were declared to be ... NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, D.C. The Terra spacecraft is managed ...

  7. Christmas Island birds returning

    NASA Astrophysics Data System (ADS)

    Six months after their mass exodus, birds are beginning to return to Christmas Island. Roughly 17 million birds, almost the entire adult bird population, either perished or fled their mid-Pacific atoll home last autumn, leaving behind thousands of nestlings to starve (Eos, April 5, 1983, p. 131). It is believed that the strong El Niño altered the ecology of the surrounding waters and forced the birds to flee. Christmas Island is the world's largest coral atoll.“Ocean and atmosphere scientists are unsure of future directions for the El Niño conditions and cannot now predict what will happen to the birds in the coming months,” said Ralph W. Schreiber, curator of ornithology at the Natural History Museum of Los Angeles County in California. Heisthe ornithologist who discovered the disappearance. “The recovery of the bird populations depends on the food supply in the waters surrounding the island.” The island's birds feed exclusively on small fish and squid.

  8. Multidecadal shoreline changes of atoll islands in the Marshall Islands

    NASA Astrophysics Data System (ADS)

    Ford, M.

    2012-12-01

    Atoll islands are considered highly vulnerable to the impacts of continued sea level rise. One of the most commonly predicted outcomes of continued sea level rise is widespread and chronic shoreline erosion. Despite the widespread implications of predicted erosion, the decadal scale changes of atoll island shorelines are poorly resolved. The Marshall Islands is one of only four countries where the majority of inhabited land is comprised of reef and atoll islands. Consisting of 29 atolls and 5 mid-ocean reef islands, the Marshall Islands are considered highly vulnerable to the impacts of sea level rise. A detailed analysis of shoreline change on over 300 islands on 10 atolls was undertaken using historic aerial photos (1945-1978) and modern high resolution satellite imagery (2004-2012). Results highlight the complex and dynamic nature of atoll islands, with significant shifts in shoreline position observed over the period of analysis. Results suggest shoreline accretion is the dominant mode of change on the islands studied, often associated with a net increase in vegetated island area. However, considerable inter- and intra-atoll variability exists with regards to shoreline stability. Findings are discussed with respect to island morphodynamics and potential hazard mitigation and planning responses within atoll settings.

  9. Black holes, antivirulence genes, and gene inactivation in the evolution of bacterial pathogens.

    PubMed

    Maurelli, Anthony T

    2007-02-01

    The evolution of bacterial pathogens from nonpathogenic ancestors is marked principally by the acquisition of virulence gene clusters on plasmids and pathogenicity islands via horizontal gene transfer. The flip side of this evolutionary force is the equally important adaptation of the newly minted pathogen to its new host niche. Pathoadaptive mutations take the form of modification of gene expression such that the pathogen is better fit to survive within the new niche. This mini-review describes the concept of pathoadaptation by loss of gene function. In this process, genes that are no longer compatible with the novel lifestyle of the pathogen are selectively inactivated either by point mutation, insertion, or deletion. These genes are called 'antivirulence genes'. Selective pressure sometimes leads to the deletion of large regions of the genome that contain antivirulence genes generating 'black holes' in the pathogen genome. Inactivation of antivirulence genes leads to a pathogen that is highly adapted to its host niche. Identification of antivirulence genes for a particular pathogen can lead to a better understanding of how it became a pathogen and the types of genetic traits that need to be silenced in order for the pathogen to colonize its new host niche successfully.

  10. Magnetic island induced bootstrap current on island dynamics in tokamaks

    SciTech Connect

    Shaing, K.C.; Spong, D.A.

    2006-02-15

    When a magnetic island is embedded in toroidally symmetric tokamaks, the toroidal symmetry in |B| is broken [K. C. Shaing, Phys. Rev. Lett. 87, 245003 (2001)]. Here, B is the magnetic field. This broken symmetry induces an additional bootstrap current density in the vicinity of the island. It is illustrated that this island induced bootstrap current density modifies the island evolution equation and imposes a lower limit on the absolute value of the tearing mode stability parameter {delta}{sup '} for the island to be unstable. This lower limit depends on the local poloidal plasma beta {beta}{sub p}, the ratio of the plasma pressure to the poloidal magnetic field pressure. If {beta}{sub p} is high enough, the magnetic island is stable. This mechanism provides an alternative route to stabilize the island.

  11. Magnetic Island Induced Bootstrap Current on Island Dynamics in Tokamaks

    SciTech Connect

    Spong, Donald A; Shaing, K. C.

    2006-02-01

    When a magnetic island is embedded in toroidally symmetric tokamaks, the toroidal symmetry in |B| is broken [K. C. Shaing, Phys. Rev. Lett. 87, 245003 (2001)] . Here, B is the magnetic field. This broken symmetry induces an additional bootstrap current density in the vicinity of the island. It is illustrated that this island induced bootstrap current density modifies the island evolution equation and imposes a lower limit on the absolute value of the tearing mode stability parameter |{Delta}{prime}| for the island to be unstable. This lower limit depends on the local poloidal plasma beta {beta}{sub p}, the ratio of the plasma pressure to the poloidal magnetic field pressure. If {beta}{sub p} is high enough, the magnetic island is stable. This mechanism provides an alternative route to stabilize the island.

  12. Host-pathogen interaction in invasive Salmonellosis.

    PubMed

    de Jong, Hanna K; Parry, Chris M; van der Poll, Tom; Wiersinga, W Joost

    2012-01-01

    Salmonella enterica infections result in diverse clinical manifestations. Typhoid fever, caused by S. enterica serovar Typhi (S. Typhi) and S. Paratyphi A, is a bacteremic illness but whose clinical features differ from other Gram-negative bacteremias. Non-typhoidal Salmonella (NTS) serovars cause self-limiting diarrhea with occasional secondary bacteremia. Primary NTS bacteremia can occur in the immunocompromised host and infants in sub-Saharan Africa. Recent studies on host-pathogen interactions in Salmonellosis using genome sequencing, murine models, and patient studies have provided new insights. The full genome sequences of numerous S. enterica serovars have been determined. The S. Typhi genome, compared to that of S. Typhimurium, harbors many inactivated or disrupted genes. This can partly explain the different immune responses both serovars induce upon entering their host. Similar genome degradation is also observed in the ST313 S. Typhimurium strain implicated in invasive infection in sub-Saharan Africa. Virulence factors, most notably, type III secretion systems, Vi antigen, lipopolysaccharide and other surface polysaccharides, flagella, and various factors essential for the intracellular life cycle of S. enterica have been characterized. Genes for these factors are commonly carried on Salmonella Pathogenicity Islands (SPIs). Plasmids also carry putative virulence-associated genes as well as those responsible for antimicrobial resistance. The interaction of Salmonella pathogen-associated molecular patterns (PAMPs) with Toll-like receptors (TLRs) and NOD-like receptors (NLRs) leads to inflammasome formation, activation, and recruitment of neutrophils and macrophages and the production of pro-inflammatory cytokines, most notably interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF)-α, and interferon-gamma (IFN)-γ. The gut microbiome may be an important modulator of this immune response. S. Typhimurium usually causes a local intestinal immune response

  13. 78 FR 58880 - Safety Zone; Catawba Island Club Wedding Event, Catawba Island Club, Catawba Island, OH

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-25

    ... DHS Department of Homeland Security FR Federal Register NPRM Notice of Proposed Rulemaking TFR... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Catawba Island Club Wedding Event, Catawba Island Club, Catawba Island, OH ACTION: Temporary final rule. SUMMARY: The Coast Guard is...

  14. Virulence Plasmids of Nonsporulating Gram-Positive Pathogens.

    PubMed

    Van Tyne, Daria; Gilmore, Michael S

    2014-10-01

    Gram-positive bacteria are leading causes of many types of human infection, including pneumonia, skin and nasopharyngeal infections, as well as urinary tract and surgical wound infections among hospitalized patients. These infections have become particularly problematic because many of the species causing them have become highly resistant to antibiotics. The role of mobile genetic elements, such as plasmids, in the dissemination of antibiotic resistance among Gram-positive bacteria has been well studied; less well understood is the role of mobile elements in the evolution and spread of virulence traits among these pathogens. While these organisms are leading agents of infection, they are also prominent members of the human commensal ecology. It appears that these bacteria are able to take advantage of the intimate association between host and commensal, via virulence traits that exacerbate infection and cause disease. However, evolution into an obligate pathogen has not occurred, presumably because it would lead to rejection of pathogenic organisms from the host ecology. Instead, in organisms that exist as both commensal and pathogen, selection has favored the development of mechanisms for variability. As a result, many virulence traits are localized on mobile genetic elements, such as virulence plasmids and pathogenicity islands. Virulence traits may occur within a minority of isolates of a given species, but these minority populations have nonetheless emerged as a leading problem in infectious disease. This chapter reviews virulence plasmids in nonsporulating Gram-positive bacteria, and examines their contribution to disease pathogenesis.

  15. A New Family of Secreted Toxins in Pathogenic Neisseria Species

    PubMed Central

    Jamet, Anne; Jousset, Agnès B.; Euphrasie, Daniel; Mukorako, Paulette; Boucharlat, Alix; Ducousso, Alexia; Charbit, Alain; Nassif, Xavier

    2015-01-01

    The genus Neisseria includes both commensal and pathogenic species which are genetically closely related. However, only meningococcus and gonococcus are important human pathogens. Very few toxins are known to be secreted by pathogenic Neisseria species. Recently, toxins secreted via type V secretion system and belonging to the widespread family of contact-dependent inhibition (CDI) toxins have been described in numerous species including meningococcus. In this study, we analyzed loci containing the maf genes in N. meningitidis and N. gonorrhoeae and proposed a novel uniform nomenclature for maf genomic islands (MGIs). We demonstrated that mafB genes encode secreted polymorphic toxins and that genes immediately downstream of mafB encode a specific immunity protein (MafI). We focused on a MafB toxin found in meningococcal strain NEM8013 and characterized its EndoU ribonuclease activity. maf genes represent 2% of the genome of pathogenic Neisseria, and are virtually absent from non-pathogenic species, thus arguing for an important biological role. Indeed, we showed that overexpression of one of the four MafB toxins of strain NEM8013 provides an advantage in competition assays, suggesting a role of maf loci in niche adaptation. PMID:25569427

  16. A new family of secreted toxins in pathogenic Neisseria species.

    PubMed

    Jamet, Anne; Jousset, Agnès B; Euphrasie, Daniel; Mukorako, Paulette; Boucharlat, Alix; Ducousso, Alexia; Charbit, Alain; Nassif, Xavier

    2015-01-01

    The genus Neisseria includes both commensal and pathogenic species which are genetically closely related. However, only meningococcus and gonococcus are important human pathogens. Very few toxins are known to be secreted by pathogenic Neisseria species. Recently, toxins secreted via type V secretion system and belonging to the widespread family of contact-dependent inhibition (CDI) toxins have been described in numerous species including meningococcus. In this study, we analyzed loci containing the maf genes in N. meningitidis and N. gonorrhoeae and proposed a novel uniform nomenclature for maf genomic islands (MGIs). We demonstrated that mafB genes encode secreted polymorphic toxins and that genes immediately downstream of mafB encode a specific immunity protein (MafI). We focused on a MafB toxin found in meningococcal strain NEM8013 and characterized its EndoU ribonuclease activity. maf genes represent 2% of the genome of pathogenic Neisseria, and are virtually absent from non-pathogenic species, thus arguing for an important biological role. Indeed, we showed that overexpression of one of the four MafB toxins of strain NEM8013 provides an advantage in competition assays, suggesting a role of maf loci in niche adaptation.

  17. [Monitoring the natural foci of tularemia on Wrangel Island].

    PubMed

    Podobedova, Ia S; Meshcheriakova, I S; Demidova, T N; Kormilitsyna, M I; Mikhaĭlova, T V; Baraniuk, V V

    2013-01-01

    Long-term annual monitoring of the natural foci of tularemia was first made on Wrangel Island. The objects of the investigation were pellets of birds-myophages, blood samples from rodents, and excrements from carnivorous mammals. A total of 2626 biological samples were examined in the period 2002 to 2011. A serological test was ascertained to be the most effective method for the detection of tularemia epizooties; polymerase chain reaction should be used as an additional technique to examine blood samples, as well as rodent tubular bone debris taken from the pellets. Tularemia epizooties were registered in the populations of two species of lemmings every year, except in 2003. An intensive diffuse tularemia epizooty was first detected in this area, which emerged in 2019, peaked by spring 2011, and covered most of the island. The antigen of tularemia pathogen was identified in 43.46% of the samples under examination,which is a high quantitative indicator of the intensity of an epizootic process. The fact that positive samples are annually found in the same areas of the island suggests that the causative agent is steadily and long preserved in the parasitic system. The availability of stable and active natural tularemia foci on Wrangel Island calls for preventive measures, particularly vaccination of risk groups coming to the island to conduct researches.

  18. BK polyomavirus: emerging pathogen.

    PubMed

    Bennett, Shauna M; Broekema, Nicole M; Imperiale, Michael J

    2012-08-01

    BK polyomavirus (BKPyV) is a small double-stranded DNA virus that is an emerging pathogen in immunocompromised individuals. BKPyV is widespread in the general population, but primarily causes disease when immune suppression leads to reactivation of latent virus. Polyomavirus-associated nephropathy and hemorrhagic cystitis in renal and bone marrow transplant patients, respectively, are the most common diseases associated with BKPyV reactivation and lytic infection. In this review, we discuss the clinical relevance, effects on the host, virus life cycle, and current treatment protocols. PMID:22402031

  19. Portable pathogen detection system

    SciTech Connect

    Colston, Billy W.; Everett, Matthew; Milanovich, Fred P.; Brown, Steve B.; Vendateswaran, Kodumudi; Simon, Jonathan N.

    2005-06-14

    A portable pathogen detection system that accomplishes on-site multiplex detection of targets in biological samples. The system includes: microbead specific reagents, incubation/mixing chambers, a disposable microbead capture substrate, and an optical measurement and decoding arrangement. The basis of this system is a highly flexible Liquid Array that utilizes optically encoded microbeads as the templates for biological assays. Target biological samples are optically labeled and captured on the microbeads, which are in turn captured on an ordered array or disordered array disposable capture substrate and then optically read.

  20. The Keystone Pathogen Hypothesis

    PubMed Central

    Hajishengallis, George; Darveau, Richard P.; Curtis, Michael A.

    2012-01-01

    Recent studies have highlighted the importance of the human microbiome in host health and disease. However, for the most part the mechanisms by which the microbiome mediates disease, or protection from it, remain poorly understood. The “keystone pathogen” hypothesis holds that certain low-abundance microbial pathogens can orchestrate inflammatory disease by remodelling a normally benign microbiota into a dysbiotic one. In this Opinion, we critically assess the available literature in support of this hypothesis, which may provide a novel conceptual basis for the development of targeted diagnostic and treatment modalities for complex dysbiotic diseases. PMID:22941505

  1. LOUISIANA BARRIER ISLAND EROSION STUDY.

    USGS Publications Warehouse

    Sallenger,, Asbury H.; Penland, Shea; Williams, S. Jeffress; Suter, John R.

    1987-01-01

    During 1986, the U. S. Geological Survey and the Louisiana Geological Survey began a five-year cooperative study focused on the processes which cause erosion of barrier islands. These processes must be understood in order to predict future erosion and to better manage our coastal resources. The study area includes the Louisiana barrier islands which serve to protect 41% of the nation's wetlands. These islands are eroding faster than any other barrier islands in the United States, in places greater than 20 m/yr. The study is divided into three parts: geological development of barrier islands, quantitative processes of barrier island erosion and applications of results. The study focuses on barrier islands in Louisiana although many of the results are applicable nationwide.

  2. Molecular screening of virulence genes in extraintestinal pathogenic Escherichia coli isolated from human blood culture in Brazil.

    PubMed

    Koga, Vanessa L; Tomazetto, Geizecler; Cyoia, Paula S; Neves, Meiriele S; Vidotto, Marilda C; Nakazato, Gerson; Kobayashi, Renata K T

    2014-01-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) is one of the main etiological agents of bloodstream infections caused by Gram-negative bacilli. In the present study, 20 E. coli isolates from human hemocultures were characterized to identify genetic features associated with virulence (pathogenicity islands markers, phylogenetic group, virulence genes, plasmid profiles, and conjugative plasmids) and these results were compared with commensal isolates. The most prevalent pathogenicity island, in strains from hemoculture, were PAI IV536, described by many researchers as a stable island in enterobacteria. Among virulence genes, iutA gene was found more frequently and this gene enconding the aerobactin siderophore receptor. According to the phylogenetic classification, group B2 was the most commonly found. Additionally, through plasmid analysis, 14 isolates showed plasmids and 3 of these were shown to be conjugative. Although in stool samples of healthy people the presence of commensal strains is common, human intestinal tract may serve as a reservoir for ExPEC.

  3. Molecular evolution of Salmonella enterica serovar Typhimurium and pathogenic Escherichia coli: from pathogenesis to therapeutics.

    PubMed

    Lavigne, Jean-Philippe; Blanc-Potard, Anne-Béatrice

    2008-03-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) and certain Escherichia coli are human pathogens that have evolved through the acquisition of multiple virulence determinants by horizontal gene transfer. Similar genetic elements, as pathogenicity islands and virulence plasmids, have driven molecular evolution of virulence in both species. In addition, the contribution of prophages has been recently highlighted as a reservoir for pathogenic diversity. Characterization of horizontally acquired virulence genes has several clinical implications. First, identification of virulence determinants that have a sporadic distribution and are specifically associated with a pathotype and/or a pathology can be useful markers for risk assessment and diagnosis. Secondly, virulence factors widely distributed in pathogenic strains, but absent from non-pathogenic bacteria, are interesting targets for the development of novel antimicrobial chemotherapies and vaccines. Here, we summarize the horizontally acquired virulence factors of S. Typhimurium, enterohemorrhagic E. coli O157:H7 and uropathogenic E. coli, and we describe their use in novel therapeutic approaches.

  4. FLANDERS FIELDS MEMORIAL IN TRAFFIC ISLAND ON EAST DRIVE. VIEW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    FLANDERS FIELDS MEMORIAL IN TRAFFIC ISLAND ON EAST DRIVE. VIEW TO NORTHEAST. - Rock Island National Cemetery, Rock Island Arsenal, 0.25 mile north of southern tip of Rock Island, Rock Island, Rock Island County, IL

  5. On detection and assessment of statistical significance of Genomic Islands

    PubMed Central

    Chatterjee, Raghunath; Chaudhuri, Keya; Chaudhuri, Probal

    2008-01-01

    Background Many of the available methods for detecting Genomic Islands (GIs) in prokaryotic genomes use markers such as transposons, proximal tRNAs, flanking repeats etc., or they use other supervised techniques requiring training datasets. Most of these methods are primarily based on the biases in GC content or codon and amino acid usage of the islands. However, these methods either do not use any formal statistical test of significance or use statistical tests for which the critical values and the P-values are not adequately justified. We propose a method, which is unsupervised in nature and uses Monte-Carlo statistical tests based on randomly selected segments of a chromosome. Such tests are supported by precise statistical distribution theory, and consequently, the resulting P-values are quite reliable for making the decision. Results Our algorithm (named Design-Island, an acronym for Detection of Statistically Significant Genomic Island) runs in two phases. Some 'putative GIs' are identified in the first phase, and those are refined into smaller segments containing horizontally acquired genes in the refinement phase. This method is applied to Salmonella typhi CT18 genome leading to the discovery of several new pathogenicity, antibiotic resistance and metabolic islands that were missed by earlier methods. Many of these islands contain mobile genetic elements like phage-mediated genes, transposons, integrase and IS elements confirming their horizontal acquirement. Conclusion The proposed method is based on statistical tests supported by precise distribution theory and reliable P-values along with a technique for visualizing statistically significant islands. The performance of our method is better than many other well known methods in terms of their sensitivity and accuracy, and in terms of specificity, it is comparable to other methods. PMID:18380895

  6. Landscapes of Santa Rosa Island, Channel Islands National Park, California

    USGS Publications Warehouse

    Schumann, R. Randall; Minor, Scott A.; Muhs, Daniel R.; Pigati, Jeffery S.

    2014-01-01

    Santa Rosa Island (SRI) is the second-largest of the California Channel Islands. It is one of 4 east–west aligned islands forming the northern Channel Islands chain, and one of the 5 islands in Channel Islands National Park. The landforms, and collections of landforms called landscapes, of Santa Rosa Island have been created by tectonic uplift and faulting, rising and falling sea level, landslides, erosion and deposition, floods, and droughts. Landscape features, and areas delineating groups of related features on Santa Rosa Island, are mapped, classified, and described in this paper. Notable landscapes on the island include beaches, coastal plains formed on marine terraces, sand dunes, and sand sheets. In this study, the inland physiography has been classified into 4 areas based on relief and degree of fluvial dissection. Most of the larger streams on the island occupy broad valleys that have been filled with alluvium and later incised to form steep- to vertical-walled arroyos, or barrancas, leaving a relict floodplain above the present channel. A better understanding of the processes and mechanisms that created these landscapes enhances visitors’ enjoyment of their surroundings and contributes to improving land and resource management strategies in order to optimize and balance the multiple goals of conservation, preservation, restoration, and visitor experience.

  7. Cryptosporidium Pathogenicity and Virulence

    PubMed Central

    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

  8. Charge Islands Through Tunneling

    NASA Technical Reports Server (NTRS)

    Robinson, Daryl C.

    2002-01-01

    It has been recently reported that the electrical charge in a semiconductive carbon nanotube is not evenly distributed, but rather it is divided into charge "islands." This paper links the aforementioned phenomenon to tunneling and provides further insight into the higher rate of tunneling processes, which makes tunneling devices attractive. This paper also provides a basis for calculating the charge profile over the length of the tube so that nanoscale devices' conductive properties may be fully exploited.

  9. Island of Hawaii

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Three main volcanoes make up the island of Hawaii (19.5N, 155.5W): the older volcanoes Mauna Loa, Mauna Kea and the recent Kilauea seen venting steam. This color infrared image is one of a pair (see STS052-77-002) to compare the differences between color film and color infrared film. Color film presents an image as it appears to the human eye whereas color infrared imagery reduces atmospheric haze and portrays vegetation as shades of red.

  10. Campylobacter fetus subspecies contain conserved type IV secretion systems on multiple genomic islands and plasmids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The features contributing to the differences in pathogenicity of the C. fetus subspecies are unknown. Putative factors involved in pathogenesis are located in genomic islands that encode type IV secretion system (T4SS) and fic-domain (filamentation induced by cyclic AMP) proteins. In the genomes of ...

  11. Rickettsia spp. in seabird ticks from western Indian Ocean islands, 2011-2012.

    PubMed

    Dietrich, Muriel; Lebarbenchon, Camille; Jaeger, Audrey; Le Rouzic, Céline; Bastien, Matthieu; Lagadec, Erwan; McCoy, Karen D; Pascalis, Hervé; Le Corre, Matthieu; Dellagi, Koussay; Tortosa, Pablo

    2014-05-01

    We found a diversity of Rickettsia spp. in seabird ticks from 6 tropical islands. The bacteria showed strong host specificity and sequence similarity with strains in other regions. Seabird ticks may be key reservoirs for pathogenic Rickettsia spp., and bird hosts may have a role in dispersing ticks and tick-associated infectious agents over large distances.

  12. Rickettsia spp. in Seabird Ticks from Western Indian Ocean Islands, 2011–2012

    PubMed Central

    Lebarbenchon, Camille; Jaeger, Audrey; Le Rouzic, Céline; Bastien, Matthieu; Lagadec, Erwan; McCoy, Karen D.; Pascalis, Hervé; Le Corre, Matthieu; Dellagi, Koussay; Tortosa, Pablo

    2014-01-01

    We found a diversity of Rickettsia spp. in seabird ticks from 6 tropical islands. The bacteria showed strong host specificity and sequence similarity with strains in other regions. Seabird ticks may be key reservoirs for pathogenic Rickettsia spp., and bird hosts may have a role in dispersing ticks and tick-associated infectious agents over large distances. PMID:24751287

  13. [Streptococcus pyogenes pathogenic factors].

    PubMed

    Bidet, Ph; Bonacorsi, S

    2014-11-01

    The pathogenicity of ß-hemolytic group A streptococcus (GAS) is particularly diverse, ranging from mild infections, such as pharyngitis or impetigo, to potentially debilitating poststreptococcal diseases, and up to severe invasive infections such as necrotizing fasciitis or the dreaded streptococcal toxic shock syndrome. This variety of clinical expressions, often radically different in individuals infected with the same strain, results from a complex interaction between the bacterial virulence factors, the mode of infection and the immune system of the host. Advances in comparative genomics have led to a better understanding of how, following this confrontation, GAS adapts to the immune system's pressure, either peacefully by reducing the expression of certain virulence factors to achieve an asymptomatic carriage, or on the contrary, by overexpressing them disproportionately, resulting in the most severe forms of invasive infection. PMID:25456681

  14. Flagella and bacterial pathogenicity.

    PubMed

    Duan, Qiangde; Zhou, Mingxu; Zhu, Liqian; Zhu, Guoqiang

    2013-01-01

    As locomotive organelles, flagella allow bacteria to move toward favorable environments. A flagellum consists of three parts: the basal structure (rotary motor), the hook (universal joint), and the filament (helical propeller). For ages, flagella have been generally regarded as important virulence factors, mainly because of their motility property. However, flagella are getting recognized to play multiple roles with more functions besides motility and chemotaxis. Recent evidence has pinpointed that the bacterial flagella participate in many additional processes including adhesion, biofilm formation, virulence factor secretion, and modulation of the immune system of eukaryotic cells. This mini-review summarizes data from recent studies that elucidated how flagella, as a virulence factor, contribute to bacterial pathogenicity.

  15. Flagella and bacterial pathogenicity.

    PubMed

    Duan, Qiangde; Zhou, Mingxu; Zhu, Liqian; Zhu, Guoqiang

    2013-01-01

    As locomotive organelles, flagella allow bacteria to move toward favorable environments. A flagellum consists of three parts: the basal structure (rotary motor), the hook (universal joint), and the filament (helical propeller). For ages, flagella have been generally regarded as important virulence factors, mainly because of their motility property. However, flagella are getting recognized to play multiple roles with more functions besides motility and chemotaxis. Recent evidence has pinpointed that the bacterial flagella participate in many additional processes including adhesion, biofilm formation, virulence factor secretion, and modulation of the immune system of eukaryotic cells. This mini-review summarizes data from recent studies that elucidated how flagella, as a virulence factor, contribute to bacterial pathogenicity. PMID:22359233

  16. Pathogenic effects of asbestos.

    PubMed

    Kannerstein, M; Churg, J; McCaughey, E; Selikoff, I J

    1977-12-01

    The enormous increase in the use of asbestos during this century has necessitated the intensive study of its pathogenic effects. The occurrence of pulmonary parenchymal and pleural fibrosis and an increased prevalence of pulmonary and gastrointestinal carcinoma and of pleural and peritoneal mesothelioma have been established. A relationship, also, to laryngeal carcinoma is probable. Mesothelioma has been associated with indirect occupational, domestic, and neighborhood exposure, and the possibility of a similar correlation of pulmonary carcinoma with low exposure has been suggested. Pulmonary fibrosis and pleural plaques have been demonstrated under these circumstances. The physical characteristics of the asbestos fiber appear to be the principal factors in its carcinogenic action. The ability of fine, short fibers, especially fragmented chrysotile, to reach the pleura would appear to account for many of the pathogenetic and anatomical features of asbestos-related disease.

  17. Rapid Detection of Pathogens

    SciTech Connect

    David Perlin

    2005-08-14

    Pathogen identification is a crucial first defense against bioterrorism. A major emphasis of our national biodefense strategy is to establish fast, accurate and sensitive assays for diagnosis of infectious diseases agents. Such assays will ensure early and appropriate treatment of infected patients. Rapid diagnostics can also support infection control measures, which monitor and limit the spread of infectious diseases agents. Many select agents are highly transmissible in the early stages of disease, and it is critical to identify infected patients and limit the risk to the remainder of the population and to stem potential panic in the general population. Nucleic acid-based molecular approaches for identification overcome many of the deficiencies associated with conventional culture methods by exploiting both large- and small-scale genomic differences between organisms. PCR-based amplification of highly conserved ribosomal RNA (rRNA) genes, intergenic sequences, and specific toxin genes is currently the most reliable approach for bacterial, fungal and many viral pathogenic agents. When combined with fluorescence-based oligonucleotide detection systems, this approach provides real-time, quantitative, high fidelity analysis capable of single nucleotide allelic discrimination (4). These probe systems offer rapid turn around time (<2 h) and are suitable for high throughput, automated multiplex operations that are critical for clinical diagnostic laboratories. In this pilot program, we have used molecular beacon technology invented at the Public health Research Institute to develop a new generation of molecular probes to rapidly detect important agents of infectious diseases. We have also developed protocols to rapidly extract nucleic acids from a variety of clinical specimen including and blood and tissue to for detection in the molecular assays. This work represented a cooperative research development program between the Kramer-Tyagi/Perlin labs on probe development

  18. Microsporidia: emerging pathogenic protists.

    PubMed

    Weiss, L M

    2001-02-23

    Microsporidia are eukaryotic spore forming obligate intracellular protozoan parasites first recognized over 100 years ago. These organisms infect all of the major animal groups and are now recognized as opportunistic pathogens of humans. Microsporidian spores are common in the environment and microsporidia pathogenic to humans have been found in water supplies. The genera Nosema, Vittaforma, Brachiola, Pleistophora, Encephalitozoon, Enterocytozoon, Septata (reclassified to Encephalitozoon) and Trachipleistophora have been found in human infections. These organisms have the smallest known eukaryotic genomes. Microsporidian ribosomal RNA sequences have proven useful as diagnostic tools as well as for phylogenetic analysis. Recent phylogenetic analysis suggests that Microsporidia are related to the fungi. These organisms are defined by the presence of a unique invasion organelle consisting of a single polar tube that coils around the interior of the spore. All microsporidia exhibit the same response to stimuli, that is, the polar tube discharges from the anterior pole of the spore in an explosive reaction. If the polar tube is discharged next to a cell, it can pierce the cell and transfer its sporoplasm into the cell. A technique was developed for the purification of polar tube proteins (PTPs) using differential extraction followed by reverse phase HPLC. This method was used to purify the PTPs from Glugea americanus, Encephalitozoon cuniculi, Enc. hellem and Enc. intestinalis. These PTPs demonstrate conserved characteristics such as solubility, hydrophobicity, mass, proline content and immunologic epitopes. The major PTP gene from Enc. cuniculi and Enc. hellem has been cloned and expressed in vitro. The gene sequences support the importance of ER and in the formation of the polar tube as suggested by morphologic studies. Analysis of the cloned proteins also indicates that secondary structural characteristics are conserved. These characteristics are probably important

  19. Fungal pathogens of Proteaceae.

    PubMed

    Crous, P W; Summerell, B A; Swart, L; Denman, S; Taylor, J E; Bezuidenhout, C M; Palm, M E; Marincowitz, S; Groenewald, J Z

    2011-12-01

    Species of Leucadendron, Leucospermum and Protea (Proteaceae) are in high demand for the international floriculture market due to their brightly coloured and textured flowers or bracts. Fungal pathogens, however, create a serious problem in cultivating flawless blooms. The aim of the present study was to characterise several of these pathogens using morphology, culture characteristics, and DNA sequence data of the rRNA-ITS and LSU genes. In some cases additional genes such as TEF 1-α and CHS were also sequenced. Based on the results of this study, several novel species and genera are described. Brunneosphaerella leaf blight is shown to be caused by three species, namely B. jonkershoekensis on Protea repens, B. nitidae sp. nov. on Protea nitida and B. protearum on a wide host range of Protea spp. (South Africa). Coniothyrium-like species associated with Coniothyrium leaf spot are allocated to other genera, namely Curreya grandicipis on Protea grandiceps, and Microsphaeropsis proteae on P. nitida (South Africa). Diaporthe leucospermi is described on Leucospermum sp. (Australia), and Diplodina microsperma newly reported on Protea sp. (New Zealand). Pyrenophora blight is caused by a novel species, Pyrenophora leucospermi, and not Drechslera biseptata or D. dematoidea as previously reported. Fusicladium proteae is described on Protea sp. (South Africa), Pestalotiopsis protearum on Leucospermum cuneiforme (Zimbabwe), Ramularia vizellae and R. stellenboschensis on Protea spp. (South Africa), and Teratosphaeria capensis on Protea spp. (Portugal, South Africa). Aureobasidium leaf spot is shown to be caused by two species, namely A. proteae comb. nov. on Protea spp. (South Africa), and A. leucospermi sp. nov. on Leucospermum spp. (Indonesia, Portugal, South Africa). Novel genera and species elucidated in this study include Gordonomyces mucovaginatus and Pseudopassalora gouriqua (hyphomycetes), and Xenoconiothyrium catenata (coelomycete), all on Protea spp. (South Africa).

  20. Multiplex detection of respiratory pathogens

    DOEpatents

    McBride, Mary; Slezak, Thomas; Birch, James M.

    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.

  1. Host Specificity of Bacterial Pathogens

    PubMed Central

    Bäumler, Andreas; Fang, Ferric C.

    2013-01-01

    Most pathogens are able to infect multiple hosts but some are highly adapted to a single-host species. A detailed understanding of the basis of host specificity can provide important insights into molecular pathogenesis, the evolution of pathogenic microbes, and the potential for pathogens to cross the species barrier to infect new hosts. Comparative genomics and the development of humanized mouse models have provided important new tools with which to explore the basis of generalism and specialism. This review will examine host specificity of bacterial pathogens with a focus on generalist and specialist serovars of Salmonella enterica. PMID:24296346

  2. 32 CFR 935.62 - Island Attorney.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 6 2013-07-01 2013-07-01 false Island Attorney. 935.62 Section 935.62 National... WAKE ISLAND CODE Judiciary § 935.62 Island Attorney. There is an Island Attorney, appointed by the General Counsel as needed. The Island Attorney shall serve at the pleasure of the General Counsel....

  3. 32 CFR 935.62 - Island Attorney.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Island Attorney. 935.62 Section 935.62 National... WAKE ISLAND CODE Judiciary § 935.62 Island Attorney. There is an Island Attorney, appointed by the General Counsel as needed. The Island Attorney shall serve at the pleasure of the General Counsel....

  4. 32 CFR 935.62 - Island Attorney.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Island Attorney. 935.62 Section 935.62 National... WAKE ISLAND CODE Judiciary § 935.62 Island Attorney. There is an Island Attorney, appointed by the General Counsel as needed. The Island Attorney shall serve at the pleasure of the General Counsel....

  5. 32 CFR 935.62 - Island Attorney.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Island Attorney. 935.62 Section 935.62 National... WAKE ISLAND CODE Judiciary § 935.62 Island Attorney. There is an Island Attorney, appointed by the General Counsel as needed. The Island Attorney shall serve at the pleasure of the General Counsel....

  6. 32 CFR 935.62 - Island Attorney.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Island Attorney. 935.62 Section 935.62 National... WAKE ISLAND CODE Judiciary § 935.62 Island Attorney. There is an Island Attorney, appointed by the General Counsel as needed. The Island Attorney shall serve at the pleasure of the General Counsel....

  7. Asthma and Native Hawaiians/Pacific Islanders

    MedlinePlus

    ... Other Pacific Islander > Asthma Asthma and Native Hawaiians/Pacific Islanders Native Hawaiians/Pacific Islanders are 70 percent more likely to have ... being told they had asthma, 2014 Native Hawaiian/Pacific Islander Non-Hispanic White Native Hawaiian/Pacific Islander/ ...

  8. Review of virulence factors of enterococcus: an emerging nosocomial pathogen.

    PubMed

    Giridhara Upadhyaya, P M; Ravikumar, K L; Umapathy, B L

    2009-01-01

    Enterococcus, considered a normal commensal of intestinal tract, is fast emerging as a pathogen causing serious and life threatening hospital borne infections. This is attributed to acquisition of multi drug resistance and virulence factors of the organisms. The sequencing of Enterococcus faecalis has given a lot of insight into its genetic makeup. The E. faecalis strain V583, which has been sequenced, contains a total of 3182 open reading frames (ORFs) with 1760 of these showing similarity to known proteins and 221 of unknown functions. Strikingly unique to this genome is the fact that over 25% of the genome is made up of mobile and exogenously acquired DNA which includes a number of conjugative and composite transposons, a pathogenicity island, integrated plasmid genes and phage regions, and a high number of insertion sequence (IS) elements. This review addresses the genomic arrangement and the study of virulence factors that have occurred since the sequencing of the genome. PMID:19736397

  9. Crustose coralline algal diseases in the U.S.-Affiliated Pacific Islands

    NASA Astrophysics Data System (ADS)

    Vargas-Ángel, Bernardo

    2010-12-01

    Despite the critical role of crustose coralline algae (CCA) in coral reef formation, maintenance, and ecology, little is known about coralline algal disease abundance, distribution, etiology, or the potential implications of declining CCA flora. This paper presents the first quantitative study of CCA disease on U.S. Pacific coral reefs, based on Rapid Ecological Assessments conducted at 337 discrete sites, at 42 different U.S.-Affiliated Pacific Islands and Atolls, within 5 major geographical regions: main Hawaiian Islands, Northwestern Hawaiian Islands, American Samoa, the Pacific Remote Island Areas (PRIA), and Guam and the Commonwealth of the Northern Mariana Islands (CNMI). Five major disease categories were enumerated, and a disease occurrence index was estimated, based on case counts relative to percent CCA cover. CCA disease occurrence exhibited considerable spatial variability both between and within islands/atolls, with some regions being disproportionately affected by disease. No diseases were observed at remote Johnston and Wake Atolls, or the main Hawaiian Islands. Diseases were rare in the Northwestern Hawaiian Islands and the Northern Mariana Islands; occasional to common around the PRIA, and common to abundant in American Samoa, Guam, and the Southern Mariana Islands. Pacific-wide, disease occurrence was statistically associated with CCA percent cover and sea surface temperatures (SSTs) but not with human population density; nonetheless, disease occurrence and population density were statistically correlated for those islands containing disease. Although Pacific-wide, the occurrence of disease was low, with no active outbreaks detected in any region, hot spots of disease were detected around Guam, the southern CNMI, American Samoa, and the PRIA. The high levels of spatial and temporal variability in disease occurrence herein underscore the patchy nature and fluctuating distribution dynamics of these afflictions. Also, the widespread dispersal

  10. Pathogenic agents in freshwater resources

    NASA Astrophysics Data System (ADS)

    Geldreich, Edwin E.

    1996-02-01

    Numerous pathogenic agents have been found in freshwaters used as sources for water supplies, recreational bathing and irrigation. These agents include bacterial pathogens, enteric viruses, several protozoans and parasitic worms more common to tropical waters. Although infected humans are a major source of pathogens, farm animals (cattle, sheep, pigs), animal pets (dogs, cats) and wildlife serve as significant reservoirs and should not be ignored. The range of infected individuals within a given warm-blooded animal group (humans included) may range from 1 to 25%. Survival times for pathogens in the water environment may range from a few days to as much as a year (Ascaris, Taenia eggs), with infective dose levels varying from one viable cell for several primary pathogenic agents to many thousands of cells for a given opportunistic pathogen.As pathogen detection in water is complex and not readily incorporated into routine monitoring, a surrogate is necessary. In general, indicators of faecal contamination provide a positive correlation with intestinal pathogen occurrences only when appropriate sample volumes are examined by sensitive methodology.Pathways by which pathogens reach susceptible water users include ingestion of contaminated water, body contact with polluted recreational waters and consumption of salad crops irrigated by polluted freshwaters. Major contributors to the spread of various water-borne pathogens are sewage, polluted surface waters and stormwater runoff. All of these contributions are intensified during periods of major floods. Several water-borne case histories are cited as examples of breakdowns in public health protection related to water supply, recreational waters and the consumption of contaminated salad crops. In the long term, water resource management must focus on pollution prevention from point sources of waste discharges and the spread of pathogens in watershed stormwater runoff.

  11. Island biogeography of the Anthropocene.

    PubMed

    Helmus, Matthew R; Mahler, D Luke; Losos, Jonathan B

    2014-09-25

    For centuries, biogeographers have examined the factors that produce patterns of biodiversity across regions. The study of islands has proved particularly fruitful and has led to the theory that geographic area and isolation influence species colonization, extinction and speciation such that larger islands have more species and isolated islands have fewer species (that is, positive species-area and negative species-isolation relationships). However, experimental tests of this theory have been limited, owing to the difficulty in experimental manipulation of islands at the scales at which speciation and long-distance colonization are relevant. Here we have used the human-aided transport of exotic anole lizards among Caribbean islands as such a test at an appropriate scale. In accord with theory, as anole colonizations have increased, islands impoverished in native species have gained the most exotic species, the past influence of speciation on island biogeography has been obscured, and the species-area relationship has strengthened while the species-isolation relationship has weakened. Moreover, anole biogeography increasingly reflects anthropogenic rather than geographic processes. Unlike the island biogeography of the past that was determined by geographic area and isolation, in the Anthropocene--an epoch proposed for the present time interval--island biogeography is dominated by the economic isolation of human populations.

  12. Cognitive Constraints and Island Effects

    PubMed Central

    Hofmeister, Philip; Sag, Ivan A.

    2012-01-01

    Competence-based theories of island effects play a central role in generative grammar, yet the graded nature of many syntactic islands has never been properly accounted for. Categorical syntactic accounts of island effects have persisted in spite of a wealth of data suggesting that island effects are not categorical in nature and that non-structural manipulations that leave island structures intact can radically alter judgments of island violations. We argue here, building on work by Deane, Kluender, and others, that processing factors have the potential to account for this otherwise unexplained variation in acceptability judgments. We report the results of self-paced reading experiments and controlled acceptability studies which explore the relationship between processing costs and judgments of acceptability. In each of the three self-paced reading studies, the data indicate that the processing cost of different types of island violations can be significantly reduced to a degree comparable to that of non-island filler-gap constructions by manipulating a single non-structural factor. Moreover, this reduction in processing cost is accompanied by significant improvements in acceptability. This evidence favors the hypothesis that island-violating constructions involve numerous processing pressures that aggregate to drive processing difficulty above a threshold so that a perception of unacceptability ensues. We examine the implications of these findings for the grammar of filler-gap dependencies.* PMID:22661792

  13. Island biogeography of the Anthropocene.

    PubMed

    Helmus, Matthew R; Mahler, D Luke; Losos, Jonathan B

    2014-09-25

    For centuries, biogeographers have examined the factors that produce patterns of biodiversity across regions. The study of islands has proved particularly fruitful and has led to the theory that geographic area and isolation influence species colonization, extinction and speciation such that larger islands have more species and isolated islands have fewer species (that is, positive species-area and negative species-isolation relationships). However, experimental tests of this theory have been limited, owing to the difficulty in experimental manipulation of islands at the scales at which speciation and long-distance colonization are relevant. Here we have used the human-aided transport of exotic anole lizards among Caribbean islands as such a test at an appropriate scale. In accord with theory, as anole colonizations have increased, islands impoverished in native species have gained the most exotic species, the past influence of speciation on island biogeography has been obscured, and the species-area relationship has strengthened while the species-isolation relationship has weakened. Moreover, anole biogeography increasingly reflects anthropogenic rather than geographic processes. Unlike the island biogeography of the past that was determined by geographic area and isolation, in the Anthropocene--an epoch proposed for the present time interval--island biogeography is dominated by the economic isolation of human populations. PMID:25254475

  14. Bacterial evolution by genomic island transfer occurs via DNA transformation in planta.

    PubMed

    Lovell, Helen C; Mansfield, John W; Godfrey, Scott A C; Jackson, Robert W; Hancock, John T; Arnold, Dawn L

    2009-09-29

    Our understanding of the evolution of microbial pathogens has been advanced by the discovery of "islands" of DNA that differ from core genomes and contain determinants of virulence. The acquisition of genomic islands (GIs) by horizontal gene transfer (HGT) is thought to have played a major role in microbial evolution. There are, however, few practical demonstrations of the acquisition of genes that control virulence, and, significantly, all have been achieved outside the animal or plant host. Loss of a GI from the bean pathogen Pseudomonas syringae pv. phaseolicola (Pph) is driven by exposure to the stress imposed by the plant's resistance response. Here, we show that the complete episomal island, which carries pathogenicity genes including the effector avrPphB, transfers between strains of Pph by transformation in planta and inserts at a specific att site in the genome of the recipient. Our results show that the evolution of bacterial pathogens by HGT may be achieved via transformation, the simplest mechanism of DNA exchange. This process is activated by exposure to plant defenses, when the pathogen is in greatest need of acquiring new genetic traits to alleviate the antimicrobial stress imposed by plant innate immunity.

  15. Common themes in microbial pathogenicity.

    PubMed Central

    Finlay, B B; Falkow, S

    1989-01-01

    A bacterial pathogen is a highly adapted microorganism which has the capacity to cause disease. The mechanisms used by pathogenic bacteria to cause infection and disease usually include an interactive group of virulence determinants, sometimes coregulated, which are suited for the interaction of a particular microorganism with a specific host. Because pathogens must overcome similar host barriers, common themes in microbial pathogenesis have evolved. However, these mechanisms are diverse between species and not necessarily conserved; instead, convergent evolution has developed several different mechanisms to overcome host barriers. The success of a bacterial pathogen can be measured by the degree with which it replicates after entering the host and reaching its specific niche. Successful microbial infection reflects persistence within a host and avoidance or neutralization of the specific and nonspecific defense mechanisms of the host. The degree of success of a pathogen is dependent upon the status of the host. As pathogens pass through a host, they are exposed to new environments. Highly adapted pathogenic organisms have developed biochemical sensors exquisitely designed to measure and respond to such environmental stimuli and accordingly to regulate a cascade of virulence determinants essential for life within the host. The pathogenic state is the product of dynamic selective pressures on microbial populations. PMID:2569162

  16. USEPA PATHOGEN EQUIVALENCY COMMITTEE RETREAT

    EPA Science Inventory

    The Pathogen Equivalency Committee held its retreat from September 20-21, 2005 at Hueston Woods State Park in College Corner, Ohio. This presentation will update the PEC’s membership on emerging pathogens, analytical methods, disinfection techniques, risk analysis, preparat...

  17. Islands of the Arctic

    NASA Astrophysics Data System (ADS)

    Dowdeswell, Julian; Hambrey, Michael

    2002-11-01

    The Arctic islands are characterized by beautiful mountains and glaciers, in which the wildlife lives in delicate balance with its environment. It is a fragile region with a long history of exploration and exploitation that is now experiencing rapid environmental change. All of these themes are explored in Islands of the Arctic, a richly illustrated volume with superb photographs from the Canadian Arctic archipelago, Greenland, Svalbard and the Russian Arctic. It begins with the various processes shaping the landscape: glaciers, rivers and coastal processes, the role of ice in the oceans and the weather and climate. Julian Dowdeswell and Michael Hambrey describe the flora and fauna in addition to the human influences on the environment, from the sustainable approach of the Inuit, to the devastating damage inflicted by hunters and issues arising from the presence of military security installations. Finally, they consider the future prospects of the Arctic islands Julian Dowdeswell is Director of the Scott Polar Research Institute and Professor of Physical Geography at 0he University of Cambridge. He received the Polar Medal from Queen Elizabeth for his contributions to the study of glacier geophysics and the Gill Memorial Award from the Royal Geographical Society. He is chair of the Publications Committee of the International Glaciological Society and head of the Glaciers and Ice Sheets Division of the International Commission for Snow and Ice. Michael Hambrey is Director of the Centre for Glaciology at the University of Wales, Aberystwyth. A past recipient of the Polar Medal, he was also given the Earth Science Editors' Outstanding Publication Award for Glaciers (Cambridge University Press). Hambrey is also the author of Glacial Environments (British Columbia, 1994).

  18. Phage therapy treatment of the coral pathogen Vibrio coralliilyticus

    PubMed Central

    Cohen, Yossi; Joseph Pollock, F; Rosenberg, Eugene; Bourne, David G

    2013-01-01

    Vibrio coralliilyticus is an important coral pathogen demonstrated to cause disease outbreaks worldwide. This study investigated the feasibility of applying bacteriophage therapy to treat the coral pathogen V. coralliilyticus. A specific bacteriophage for V. coralliilyticus strain P1 (LMG23696), referred to here as bacteriophage YC, was isolated from the seawater above corals at Nelly Bay, Magnetic Island, central Great Barrier Reef (GBR), the same location where the bacterium was first isolated. Bacteriophage YC was shown to be a lytic phage belonging to the Myoviridae family, with a rapid replication rate, high burst size, and high affinity to its host. By infecting its host bacterium, bacteriophage YC was able to prevent bacterial-induced photosystem inhibition in pure cultures of Symbiodinium, the photosymbiont partner of coral and a target for virulence factors produced by the bacterial pathogen. Phage therapy experiments using coral juveniles in microtiter plates as a model system revealed that bacteriophage YC was able to prevent V. coralliilyticus-induced photoinactivation and tissue lysis. These results demonstrate that bacteriophage YC has the potential to treat coral disease outbreaks caused by the bacterial pathogen V. coralliilyticus, making it a good candidate for phage therapy treatment of coral disease. PMID:23239510

  19. Population Structure and Evolution of Pathogenicity of Yersinia pseudotuberculosis▿ †

    PubMed Central

    Ch'ng, Shear Lane; Octavia, Sophie; Xia, Qiuyu; Duong, An; Tanaka, Mark M.; Fukushima, Hiroshi; Lan, Ruiting

    2011-01-01

    Yersinia pseudotuberculosis is an enteric human pathogen but is widespread in the environment. Pathogenicity is determined by a number of virulence factors, including the virulence plasmid pYV, the high-pathogenicity island (HPI), and the Y. pseudotuberculosis-derived mitogen (YPM), a superantigen. The presence of the 3 virulence factors varies among Y. pseudotuberculosis isolates. We developed a multilocus sequence typing (MLST) scheme to address the population structure of Y. pseudotuberculosis and the evolution of its pathogenicity. The seven housekeeping genes selected for MLST were mdh, recA, sucA, fumC, aroC, pgi, and gyrB. An MLST analysis of 83 isolates of Y. pseudotuberculosis, representing 19 different serotypes and six different genetic groups, identified 61 sequence types (STs) and 12 clonal complexes. Out of 26 allelic changes that occurred in the 12 clonal complexes, 13 were mutational events while 13 were recombinational events, indicating that recombination and mutation contributed equally to the diversification of the clonal complexes. The isolates were separated into 2 distinctive clusters, A and B. Cluster A is the major cluster, with 53 STs (including Y. pestis strains), and is distributed worldwide, while cluster B is restricted to the Far East. The YPM gene is widely distributed on the phylogenetic tree, with ypmA in cluster A and ypmB in cluster B. pYV is present in cluster A only but is sporadically absent in some cluster A isolates. In contrast, an HPI is present only in a limited number of lineages and must be gained by lateral transfer. Three STs carry all 3 virulence factors and can be regarded as high-pathogenicity clones. Isolates from the same ST may not carry all 3 virulence factors, indicating frequent gain or loss of these factors. The differences in pathogenicity among Y. pseudotuberculosis strains are likely due to the variable presence and instability of the virulence factors. PMID:21131531

  20. Eddies around Guam, an island in the Mariana Islands group

    NASA Astrophysics Data System (ADS)

    Wolanski, E.; Richmond, R. H.; Davis, G.; Deleersnijder, E.; Leben, R. R.

    2003-06-01

    Near-surface currents around Guam, a 35 km long, slab-shaped island in the Mariana Islands group, were estimated from current meters, satellite-derived surface topography, and a numerical model. A dominant northwestward-flowing North Equatorial Current prevailed from June to December 2000, with speeds typically 0.1-0.2 m s -1, generating unsteady eddies in the lee of Guam. A number of transient eddies off the tips of the island were apparent, the smallest eddies were at the scale of local topographic features such as headlands and embayments, while other eddies were island size. In addition to eddies off the tips of the island, a large (200 km in diameter) cyclonic oceanic eddy was advected eastward past Guam during the last 2 weeks of August 2000. Centered on Guam for a few days, this eddy formed elsewhere and impinged on the island generating anticlockwise currents around the island of up to 0.5 m s -1. It is suggested that these eddies are sufficiently energetic to return fish and coral eggs and larvae to their natal reefs in Guam, thereby enabling self-seeding of coral reefs in Guam. The numerical model also predicts that large (up to 30 m amplitude) island-generated internal waves may occur around Guam; however, no observations are presently available to support this prediction.

  1. Islands and Non-islands in Native and Heritage Korean

    PubMed Central

    Kim, Boyoung; Goodall, Grant

    2016-01-01

    To a large extent, island phenomena are cross-linguistically invariable, but English and Korean present some striking differences in this domain. English has wh-movement and Korean does not, and while both languages show sensitivity to wh-islands, only English has island effects for adjunct clauses. Given this complex set of differences, one might expect Korean/English bilinguals, and especially heritage Korean speakers (i.e., early bilinguals whose L2 became their dominant language during childhood) to be different from native speakers, since heritage speakers have had more limited exposure to Korean, may have had incomplete acquisition and/or attrition, and may show significant transfer effects from the L2. Here we examine islands in heritage speakers of Korean in the U.S. Through a series of four formal acceptability experiments comparing these heritage speakers with native speakers residing in Korea, we show that the two groups are remarkably similar. Both show clear evidence for wh-islands and an equally clear lack of adjunct island effects. Given the very different linguistic environment that the heritage speakers have had since early childhood, this result lends support to the idea that island phenomena are largely immune to environmental influences and stem from deeper properties of the processor and/or grammar. Similarly, it casts some doubt on recent proposals that islands are learned from the input. PMID:26913017

  2. 19. New York Connecting Railroad: Randalls Island Viaduct. Randalls Island, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. New York Connecting Railroad: Randalls Island Viaduct. Randalls Island, New York Co., NY. Sec. 4207, MP 8.54. - Northeast Railroad Corridor, Amtrak Route between New Jersey/New York & New York/Connecticut State Lines, New York County, NY

  3. 15. New York Connecting Railroad: Wards Island Viaduct. Wards Island, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. New York Connecting Railroad: Wards Island Viaduct. Wards Island, New York Co., NY. Sec. 4207, MP 7.65. - Northeast Railroad Corridor, Amtrak Route between New Jersey/New York & New York/Connecticut State Lines, New York County, NY

  4. Urban heat island

    NASA Technical Reports Server (NTRS)

    Kim, Hongsuk H.

    1991-01-01

    The phenomenon of urban heat island was investigated by the use of LANDSAT Thematic Mapper data sets collected over the metropolitan area of Washington DC (U.S.). By combining the retrieved spectral albedos and temperatures, urban modification on radiation budgets of five surface categories were analyzed. The surface radiation budget imagery of the area show that urban heating is attributable to a large heat flux from the rapidly heating surfaces of asphalt, bare soil and short grass. In summer, symptoms of diurnal heating begin to appear by mid morning and can be about 10 degrees warmer than nearby woodlands in summer.

  5. Island of Hawaii

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The three main volcanoes which make up the island of Hawaii (19.5N, 155.5W) include the older large shield volcanoes Mauna Loa, Mauna Kea and the more recent Kilauea. The rift zones of Mauna Loa and Mauna Kea are delineated by the black lava flows whereas the smaler Kilauea can be seen venting steam. This color image is one of a pair (see STS052-95-037) to compare the differences between color film and color infrared film.

  6. Pine Island Glacier, Antarctica

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This pair of MISR images of the Pine Island Glacier in western Antarctica was acquired on December 12, 2000 during Terra orbit 5246. At left is a conventional, true-color image from the downward-looking (nadir) camera. The false-color image at right is a composite of red band data taken by the MISR forward 60-degree, nadir, and aftward 60-degree cameras, displayed in red, green, and blue colors, respectively. Color variations in the left (true-color) image highlight spectral differences. In the multi-angle composite, on the other hand, color variations act as a proxy for differences in the angular reflectance properties of the scene. In this representation, clouds show up as light purple. Blue to orange gradations on the surface indicate a transition in ice texture from smooth to rough. For example, the bright orange 'carrot-like' features are rough crevasses on the glacier's tongue. In the conventional nadir view, the blue ice labeled 'rough crevasses' and 'smooth blue ice' exhibit similar coloration, but the multi-angle composite reveals their different textures, with the smoother ice appearing dark purple instead of orange. This could be an indicator of different mechanisms by which this ice is exposed. The multi-angle view also reveals subtle roughness variations on the frozen sea ice between the glacier and the open water in Pine Island Bay.

    To the left of the 'icebergs' label are chunks of floating ice. Additionally, smaller icebergs embedded in the frozen sea ice are visible below and to the right of the label. These small icebergs are associated with dark streaks. Analysis of the illumination geometry suggests that these streaks are surface features, not shadows. Wind-driven motion and thinning of the sea ice in the vicinity of the icebergs is one possible explanation.

    Recently, Robert Bindschadler, a glaciologist at the NASA Goddard Space Flight Center discovered in Landsat 7 imagery a newly-formed crack traversing the Pine Island Glacier. This crack

  7. Fire Island National Seashore

    USGS Publications Warehouse

    Brock, John C.; Wright, C. Wayne; Patterson, Matt; Nayagandhi, Amar; Patterson, Judd

    2007-01-01

    These lidar-derived topographic maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, the National Park Service (NPS), Northeast Coastal and Barrier Network, Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. The aims of the partnership that created this product are to develop advanced survey techniques for mapping barrier island geomorphology and habitats, and to enable the monitoring of ecological and geological change within National Seashores. This product is based on data from an innovative airborne lidar instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Advanced Airborne Research Lidar (EAARL).

  8. Tuberculosis Epidemiology in Islands: Insularity, Hosts and Trade

    PubMed Central

    Acevedo, Pelayo; Romero, Beatriz; Vicente, Joaquin; Caracappa, Santo; Galluzzo, Paola; Marineo, Sandra; Vicari, Domenico; Torina, Alessandra; Casal, Carmen; de la Fuente, Jose; Gortazar, Christian

    2013-01-01

    Because of their relative simplicity and the barriers to gene flow, islands are ideal systems to study the distribution of biodiversity. However, the knowledge that can be extracted from this peculiar ecosystem regarding epidemiology of economically relevant diseases has not been widely addressed. We used information available in the scientific literature for 10 old world islands or archipelagos and original data on Sicily to gain new insights into the epidemiology of the Mycobacterium tuberculosis complex (MTC). We explored three nonexclusive working hypotheses on the processes modulating bovine tuberculosis (bTB) herd prevalence in cattle and MTC strain diversity: insularity, hosts and trade. Results suggest that bTB herd prevalence was positively correlated with island size, the presence of wild hosts, and the number of imported cattle, but neither with isolation nor with cattle density. MTC strain diversity was positively related with cattle bTB prevalence, presence of wild hosts and the number of imported cattle, but not with island size, isolation, and cattle density. The three most common spoligotype patterns coincided between Sicily and mainland Italy. However in Sicily, these common patterns showed a clearer dominance than on the Italian mainland, and seven of 19 patterns (37%) found in Sicily had not been reported from continental Italy. Strain patterns were not spatially clustered in Sicily. We were able to infer several aspects of MTC epidemiology and control in islands and thus in fragmented host and pathogen populations. Our results point out the relevance of the intensity of the cattle commercial networks in the epidemiology of MTC, and suggest that eradication will prove more difficult with increasing size of the island and its environmental complexity, mainly in terms of the diversity of suitable domestic and wild MTC hosts. PMID:23923053

  9. Genomic Evidence for the Evolution of Streptococcus equi: Host Restriction, Increased Virulence, and Genetic Exchange with Human Pathogens

    PubMed Central

    Paillot, Romain; Steward, Karen F.; Webb, Katy; Ainslie, Fern; Jourdan, Thibaud; Bason, Nathalie C.; Holroyd, Nancy E.; Mungall, Karen; Quail, Michael A.; Sanders, Mandy; Simmonds, Mark; Willey, David; Brooks, Karen; Aanensen, David M.; Spratt, Brian G.; Jolley, Keith A.; Maiden, Martin C. J.; Kehoe, Michael; Chanter, Neil; Bentley, Stephen D.; Robinson, Carl; Maskell, Duncan J.; Parkhill, Julian; Waller, Andrew S.

    2009-01-01

    The continued evolution of bacterial pathogens has major implications for both human and animal disease, but the exchange of genetic material between host-restricted pathogens is rarely considered. Streptococcus equi subspecies equi (S. equi) is a host-restricted pathogen of horses that has evolved from the zoonotic pathogen Streptococcus equi subspecies zooepidemicus (S. zooepidemicus). These pathogens share approximately 80% genome sequence identity with the important human pathogen Streptococcus pyogenes. We sequenced and compared the genomes of S. equi 4047 and S. zooepidemicus H70 and screened S. equi and S. zooepidemicus strains from around the world to uncover evidence of the genetic events that have shaped the evolution of the S. equi genome and led to its emergence as a host-restricted pathogen. Our analysis provides evidence of functional loss due to mutation and deletion, coupled with pathogenic specialization through the acquisition of bacteriophage encoding a phospholipase A2 toxin, and four superantigens, and an integrative conjugative element carrying a novel iron acquisition system with similarity to the high pathogenicity island of Yersinia pestis. We also highlight that S. equi, S. zooepidemicus, and S. pyogenes share a common phage pool that enhances cross-species pathogen evolution. We conclude that the complex interplay of functional loss, pathogenic specialization, and genetic exchange between S. equi, S. zooepidemicus, and S. pyogenes continues to influence the evolution of these important streptococci. PMID:19325880

  10. Physical constraints for pathogen movement.

    PubMed

    Schwarz, Ulrich S

    2015-10-01

    In this pedagogical review, we discuss the physical constraints that pathogens experience when they move in their host environment. Due to their small size, pathogens are living in a low Reynolds number world dominated by viscosity. For swimming pathogens, the so-called scallop theorem determines which kinds of shape changes can lead to productive motility. For crawling or gliding cells, the main resistance to movement comes from protein friction at the cell-environment interface. Viruses and pathogenic bacteria can also exploit intracellular host processes such as actin polymerization and motor-based transport, if they present the appropriate factors on their surfaces. Similar to cancer cells that also tend to cross various barriers, pathogens often combine several of these strategies in order to increase their motility and therefore their chances to replicate and spread.

  11. Profile: Native Hawaiians and Pacific Islanders

    MedlinePlus

    ... Hawaiian/Other Pacific Islander Profile: Native Hawaiians and Pacific Islanders (Map of the US with the states that have significant Native Hawaiian/Pacific Islander populations according to the Census Bureau) HI - ...

  12. Infant Mortality and Asians and Pacific Islanders

    MedlinePlus

    ... Infant Heath & Mortality Infant Mortality and Asians and Pacific Islanders Among Asian/Pacific Islanders, Sudden Infant Death Syndrome (SIDS) is the fourth leading cause of infant mortality. Asian/Pacific Islanders women generally have lower infant mortality rates ...

  13. Heart Disease and Asians and Pacific Islanders

    MedlinePlus

    ... American > Heart Disease Heart Disease and Asians and Pacific Islanders Overall, Asian American adults are less likely ... Disease Death Rates per 100,000 (2013) Asians/Pacific Islanders Non-Hispanic White Asians/Pacific Islanders /Non- ...

  14. Immunizations and Asians and Pacific Islanders

    MedlinePlus

    ... Profiles > Asian American > Immunizations Immunizations and Asians and Pacific Islanders Asian/Pacific Islander adults are 10% less likely to ever ... to non-Hispanic white adults. In 2014, Asian/Pacific Islander adults aged 65 years and older were ...

  15. Diabetes and Native Hawaiians/Pacific Islanders

    MedlinePlus

    ... Other Pacific Islander > Diabetes Diabetes and Native Hawaiians/Pacific Islanders Asian Americans, in general, have the same ... However, there are differences within the Native Hawaiian/Pacific Islander population. From a national survey, Native Hawaiians/ ...

  16. Salmonella enterica Replication in Hemophagocytic Macrophages Requires Two Type Three Secretion Systems▿

    PubMed Central

    Silva-Herzog, Eugenia; Detweiler, Corrella S.

    2010-01-01

    Salmonella enterica serotype Typhimurium is a natural pathogen of mice, which acquire the bacteria orally and develop systemic acute infections that can become subacute to chronic infections. S. Typhimurium can reside within hemophagocytic macrophages (HMs) in SV129S6 mice, an Slc11a1/Nramp1+/+ inbred strain. HMs are activated macrophages which have ingested viable hematopoietic cells and are a key characteristic of infectious and inflammatory diseases. Here we show that modest S. Typhimurium replication in HMs begins at 18 h postinfection, while activated macrophages kill the bacteria. For bacterial replication to occur, the phagocytosed viable cells must be grown to a low cell density and the multiplicity of infection must be low. HMs are able to kill phagocytosed Escherichia coli, produce reactive nitrogen species, and retain S. Typhimurium within membrane-bound vesicles. S. Typhimurium does not rescue E. coli upon coinfection of HMs. This indicates that S. Typhimurium does not cause HMs to become permissive for other microbes; rather, S. Typhimurium is especially equipped to survive within HMs. Two type three secretion systems (T3SS) encoded by S. Typhimurium are required for replication within HMs. While the T3SS within Salmonella pathogenicity island 2 (SPI-2) has been previously shown to be important for bacterial survival in cells, a role for SPI-1 in replication in macrophages has not been reported. The requirement for SPI-1 in HMs may help explain the role of SPI-1 during long-term colonization of mice. PMID:20515933

  17. Neoproterozoic granitoids on Wrangel Island

    NASA Astrophysics Data System (ADS)

    Luchitskaya, M. V.; Sergeev, S. A.; Sokolov, S. D.; Tuchkova, M. I.

    2016-07-01

    Based on geochronological U-Pb studies, the age of Wrangel Island granitoids was estimated as Neoproterozoic (Cryogenian). Some granitoids contain zircons with inherited cores with an estimated age of 1010, 1170, 1200, and >2600 Ma, assuming the presence of ancient (Neoarchean-Mesoproterozoic) rocks in the Wrangel Island foundation and their involvement in partial melting under granitoid magma formation.

  18. Chikungunya Fever in Japan Imported from the Caribbean Islands.

    PubMed

    Imai, Kazuo; Nakayama, Eri; Maeda, Takuya; Mikita, Kei; Kobayashi, Yukiko; Mitarai, Aoi; Honma, Yasuko; Miyake, Satoru; Kaku, Koki; Miyahira, Yasushi; Kawana, Akihiko

    2016-01-01

    A 53-year-old Japanese woman who was working as a volunteer in the Commonwealth of Dominica in the Caribbean islands presented with a high-grade fever and severe incapacitating generalized arthralgia. The Asian genotype of the chikungunya virus was confirmed using reverse transcription-PCR and serology, based on the presence of a specific neutralization titer and immunoglobulin M antibodies. She was diagnosed with post-chikungunya chronic arthritis based on persistence of her polyarthritis for 3 months and the presence of rheumatoid factor, immunoglobulin G-rheumatoid factor, and matrix metalloproteinase-3. Chikungunya virus should be considered as a causative pathogen in travelers returning from Caribbean islands. Clinicians should consider chikungunya fever in the differential diagnosis of patients who complain of chronic arthritis and have a history of travel to an endemic area.

  19. Horizontally acquired genomic islands in the tubercle bacilli.

    PubMed

    Jang, Jichan; Becq, Jennifer; Gicquel, Brigitte; Deschavanne, Patrick; Neyrolles, Olivier

    2008-07-01

    Most mycobacteria are environmental species, causing disease only occasionally when they encounter a susceptible human or animal host. A few species, such as Mycobacterium tuberculosis and Mycobacterium avium, have acquired the ability to parasitize host macrophages during the course of evolution and have become major pathogens. Recent genetic studies in these two species have suggested that early episodes of horizontal transfer of genomic islands from surrounding environmental species might have contributed to the evolution towards this virulence phenotype, possibly by helping bacilli to persist in protozoa and, subsequently, in mammalian phagocytes. A better understanding of the function of the proteins encoded by these genomic islands in mycobacterial metabolism might help to define novel targets for the development of future antimicrobials.

  20. Roentgenologic aspects of bone islands.

    PubMed

    Onitsuka, H

    1977-06-01

    A review of radiographs of 143 Adult Health Study and 46 non-sample subjects made over a period of 23 years established sites, sizes, ages at detection, and prevalence of 209 bone islands in 189 subjects. Except for 18 new bone islands, all appeared during the period of observation. Twenty-six of them changed: of these, 21 enlarged, 4 became smaller, and 1 disappeared. There was no association with atomic bomb radiation dose. Bone islands were more frequent in the pelvis and femora but often occurred in the ribs. Five bone islands in adolescents enlarged proportionally to bone growth, suggesting that they often participate metabolically in the normal osseous system. Bone islands must be differentiated from osteoblastic metastases.

  1. Host-Pathogen Interactions

    PubMed Central

    English, Patricia D.; Jurale, Joseph Byrne; Albersheim, Peter

    1971-01-01

    The effect of a number of physiological variables on the secretion of polysaccharide-degrading enzymes by culture-grown Colletotrichum lindemuthianum (Saccardo and Magnus) Scribner was determined. The number of spores used to inoculate cultures grown on isolated bean hypocotyl cell walls affects the time after inoculation at which enzyme secretion occurs, but has no significant effect on the maximal amount of enzyme ultimately secreted. Cell walls isolated from bean leaves, first internodes, or hypocotyls (susceptible to C. lindemuthianum infection), when used as carbon source for C. lindemuthianum growth, stimulate the fungus to secrete more α-galactosidase than do cell walls isolated from roots (resistant to infection). The concentration of carbon source used for fungal growth determines the final level of enzyme activity in the culture fluid. The level of enzyme secretion is not proportional to fungal growth; rather, enzyme secretion is induced. Maximal α-galactosidase activity in the culture medium is found when the concentration of cell walls used as carbon source is 1% or greater. A higher concentration of cell walls is necessary for maximal α-arabinosidase activity. Galactose, when used as the carbon source, stimulates α-galactosidase secretion but, at comparable concentrations, is less effective in doing so than are cell walls. Polysaccharide-degrading enzymes are secreted by C. lindemuthianum at different times during growth of the pathogen on isolated cell walls. Pectinase and α-arabinosidase are secreted first, followed by β-xylosidase and cellulase, then β-glucosidase, and, finally, α-galactosidase. PMID:16657562

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

    PubMed

    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.

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

    PubMed Central

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

    2015-01-01

    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. PMID:26066311

  4. Epidemiological isolation causing variable mortality in Island populations during the 1918–1920 influenza pandemic

    PubMed Central

    Shanks, G. Dennis; Hussell, Tracy; Brundage, John F.

    2012-01-01

    Please cite this paper as: Shanks et al. (2012) Epidemiological isolation causing variable mortality in Island populations during the 1918–1920 influenza pandemic. Influenza and Other Respiratory Viruses 6(6), 417–423. Background  During the 1918 pandemic period, influenza‐related mortality increased worldwide; however, mortality rates varied widely across locations and demographic subgroups. Islands are isolated epidemiological situations that may elucidate why influenza pandemic mortality rates were so variable in apparently similar populations. Objectives  Our objectives were to determine and compare the patterns of pandemic influenza mortality on islands. Methods  We reviewed historical records of mortality associated with the 1918–1920 influenza pandemic in various military and civilian groups on islands. Results and Conclusions  Mortality differed more than 50‐fold during pandemic‐related epidemics on Pacific islands [range: 0·4% (Hawaii) to 22% (Samoa)], and on some islands, mortality sharply varied among demographic subgroups of island residents such as Saipan: Chamorros [12%] and Caroline Islanders [0·4%]. Among soldiers from island populations who had completed initial military training, influenza‐related mortality rates were generally low, for example, Puerto Rico (0·7%) and French Polynesia (0·13%). The findings suggest that among island residents, those who had been exposed to multiple, antigenically diverse respiratory pathogens prior to infection with the 1918 pandemic strain (e.g., less isolated) experienced lower mortality. The continuous circulation of antigenically diverse influenza viruses and other respiratory infectious agents makes widespread high mortality during future influenza pandemics unlikely. PMID:22226378

  5. Island tameness: living on islands reduces flight initiation distance.

    PubMed

    Cooper, William E; Pyron, R Alexander; Garland, Theodore

    2014-02-22

    One of Darwin's most widely known conjectures is that prey are tame on remote islands, where mammalian predators are absent. Many species appear to permit close approach on such islands, but no comparative studies have demonstrated reduced wariness quantified as flight initiation distance (FID; i.e. predator-prey distance when the prey begins to flee) in comparison with mainland relatives. We used the phylogenetic comparative method to assess influence of distance from the mainland and island area on FID of 66 lizard species. Because body size and predator approach speed affect predation risk, we included these as independent variables. Multiple regression showed that FID decreases as distance from mainland increases and is shorter in island than mainland populations. Although FID increased as area increased in some models, collinearity made it difficult to separate effects of area from distance and island occupancy. FID increases as SVL increases and approach speed increases; these effects are statistically independent of effects of distance to mainland and island occupancy. Ordinary least-squares models fit the data better than phylogenetic regressions, indicating little or no phylogenetic signal in residual FID after accounting for the independent variables. Our results demonstrate that island tameness is a real phenomenon in lizards.

  6. Functional genomics of pathogenic bacteria.

    PubMed Central

    Moxon, E R; Hood, D W; Saunders, N J; Schweda, E K H; Richards, J C

    2002-01-01

    Microbial diseases remain the commonest cause of global mortality and morbidity. Automated-DNA sequencing has revolutionized the investigation of pathogenic microbes by making the immense fund of information contained in their genomes available at reasonable cost. The challenge is how this information can be used to increase current understanding of the biology of commensal and virulence behaviour of pathogens with particular emphasis on in vivo function and novel approaches to prevention. One example of the application of whole-genome-sequence information is afforded by investigations of the pathogenic role of Haemophilus influenzae lipopolysaccharide and its candidacy as a vaccine. PMID:11839188

  7. 2. Light tower, view west towards Squirrel Island, south and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Light tower, view west towards Squirrel Island, south and east sides - Ram Island Light Station, Ram Island, south of Ocean Point & just north of Fisherman Island, marking south side of Fisherman Island Passage, Ocean Point, Lincoln County, ME

  8. Plant communities of Santa Rosa Island, Channel Islands National Park

    USGS Publications Warehouse

    Clark, Ronilee A.; Halvorson, William L.; Sawdo, Andell A.; Danielsen, Karen C.

    1990-01-01

    A survey of the plant communities on Santa Rosa Island, Channel Islands National Park, was conducted from January through July 1988.  Vegetation data were collected at 296 sites using a releve technique.  The plant communities described include: grassland, coastal marsh, caliche scrub, coastal sage scrub, lupine scrub, baccharis scrub, coastal bluff scrub, coastal dune scrub, mixed chaparral, mixed woodland, torrey pine woodland, closed-cone pine woodland, island oak woodland, riparian woodland, and riparian herbaceous vegetation. The areal extent of each community was mapper on USGS 7.5' topographic maps, and digitized for GIS manipulation.

  9. Pine Island Glacier, Antarctica

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This ASTER image was acquired on December 12, 2000, and covers an area of 38 x 48 km. Pine Island Glacier has undergone a steady loss of elevation with retreat of the grounding line in recent decades. Now, space imagery has revealed a wide new crack that some scientists think will soon result in a calving event. Glaciologist Robert Bindschadler of NASA's Goddard Space Flight Center predicts this crack will result in the calving of a major iceberg, probably in less than 18 months. Discovery of the crack was possible due to multi-year image archives and high resolution imagery. This image is located at 74.1 degrees south latitude and 105.1 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  10. SRTM Anaglyph: Fiji Islands

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Sovereign Democratic Republic of the Fiji Islands, commonly known as Fiji, is an independent nation consisting of some 332 islands surrounding the Koro Sea in the South Pacific Ocean. This topographic image shows Viti Levu, the largest island in the group. With an area of 10,429 square kilometers (about 4000 square miles), it comprises more than half the area of the Fiji Islands. Suva, the capital city, lies on the southeast shore. The Nakauvadra, the rugged mountain range running from north to south, has several peaks rising above 900 meters (about 3000 feet). Mount Tomanivi, in the upper center, is the highest peak at 1324 meters (4341 feet). The distinct circular feature on the north shore is the Tavua Caldera, the remnant of a large shield volcano that was active about 4 million years ago. Gold has been mined on the margin of the caldera since the 1930s. The Nadrau plateau is the low relief highland in the center of the mountain range. The coastal plains in the west, northwest and southeast account for only 15 percent of Viti Levu's area but are the main centers of agriculture and settlement.

    This shaded relief anaglyph image was generated using preliminary topographic data from the Shuttle Radar Topography Mission. A computer-generated artificial light source illuminates the elevation data from the top (north) to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. The stereoscopic effect was created by first draping the shaded relief image back over the topographic data and then generating two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter.

    This image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar

  11. 'King George Island' Brushed

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Annotated Version

    This mosaic was made from frames acquired by the microscopic imager on NASA's Mars Exploration Rover Spirit during Spirit's 1,031 Martian day, or sol, on the red planet (Nov. 27, 2006). It shows a rock target called 'King George Island' after the target was brushed by the rover's rock abrasion tool. The mosaic covers approximately 6 centimeters (2.4 inches) across and shows the granular nature of the rock exposure. The grains are typically about 1 millimeter (.04 inches) wide. Data from the rover's Moessbauer spectrometer provides evidence that they have an enhanced amount of the mineral hematite relative to surrounding soils.

  12. Anatahan Volcano, Mariana Islands

    NASA Technical Reports Server (NTRS)

    2008-01-01

    In the early hours of February 7, ASTER captured this nighttime thermal infrared image of an eruption of Anatahan Volcano in the central Mariana Islands. The summit of the volcano is bright indicating there is a very hot area there. Streaming to the west is an ash plume, visible by the red color indicating the presence of silicate-rich particles. Dark grey areas are clouds that appear colder than the ocean. Anatahan is a stratovolcano that started erupting in May 2003, forming a new crater.

    The image covers an area of 56.3 x 41.8 km, and is located 16 degrees north latitude and 145.6 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  13. 78 FR 48668 - PSEG Long Island LLC, Long Island Electric Utility Servco LLC, Long Island Power Authority, Long...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-09

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission PSEG Long Island LLC, Long Island Electric Utility Servco LLC, Long Island Power Authority, Long Island Lighting Company; Notice of Petition for Declaratory Order Take notice that on August 1, 2013, pursuant to Rule...

  14. Lectins in human pathogenic fungi.

    PubMed

    Gallegos, Belém; Martínez, Ruth; Pérez, Laura; Del Socorro Pina, María; Perez, Eduardo; Hernández, Pedro

    2014-01-01

    Lectins are carbohydrate-binding proteins widely distributed in nature. They constitute a highly diverse group of proteins consisting of many different protein families that are, in general, structurally unrelated. In the last few years, mushroom and other fungal lectins have attracted wide attention due to their antitumour, antiproliferative and immunomodulatory activities. The present mini-review provides concise information about recent developments in understanding lectins from human pathogenic fungi. A bibliographic search was performed in the Science Direct and PubMed databases, using the following keywords "lectin", "fungi", "human" and "pathogenic". Lectins present in fungi have been classified; however, the role played by lectins derived from human pathogenic fungi in infectious processes remains uncertain; thus, this is a scientific field requiring more research. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012).

  15. Pathogen detection using engineered bacteriophages.

    PubMed

    Smartt, Abby E; Xu, Tingting; Jegier, Patricia; Carswell, Jessica J; Blount, Samuel A; Sayler, Gary S; Ripp, Steven

    2012-04-01

    Bacteriophages, or phages, are bacterial viruses that can infect a broad or narrow range of host organisms. Knowing the host range of a phage allows it to be exploited in targeting various pathogens. Applying phages for the identification of microorganisms related to food and waterborne pathogens and pathogens of clinical significance to humans and animals has a long history, and there has to some extent been a recent revival in these applications as phages have become more extensively integrated into novel detection, identification, and monitoring technologies. Biotechnological and genetic engineering strategies applied to phages are responsible for some of these new methods, but even natural unmodified phages are widely applicable when paired with appropriate innovative detector platforms. This review highlights the use of phages as pathogen detector interfaces to provide the reader with an up-to-date inventory of phage-based biodetection strategies.

  16. Molecular Soybean-Pathogen Interactions.

    PubMed

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

    2016-08-01

    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. PMID:27359370

  17. Lectins in human pathogenic fungi.

    PubMed

    Gallegos, Belém; Martínez, Ruth; Pérez, Laura; Del Socorro Pina, María; Perez, Eduardo; Hernández, Pedro

    2014-01-01

    Lectins are carbohydrate-binding proteins widely distributed in nature. They constitute a highly diverse group of proteins consisting of many different protein families that are, in general, structurally unrelated. In the last few years, mushroom and other fungal lectins have attracted wide attention due to their antitumour, antiproliferative and immunomodulatory activities. The present mini-review provides concise information about recent developments in understanding lectins from human pathogenic fungi. A bibliographic search was performed in the Science Direct and PubMed databases, using the following keywords "lectin", "fungi", "human" and "pathogenic". Lectins present in fungi have been classified; however, the role played by lectins derived from human pathogenic fungi in infectious processes remains uncertain; thus, this is a scientific field requiring more research. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012). PMID:24270074

  18. Global Collembola on Deception Island.

    PubMed

    Greenslade, Penelope; Potapov, Mikhail; Russell, David; Convey, Peter

    2012-01-01

    Three new non-indigenous springtail species are recorded in recent collections made on Deception Island, South Shetland Islands, maritime Antarctic: Deuteraphorura (Deuteraphorura) cebennaria (Gisin) (Collembola: Onychiuridae), Mesaphorura macrochaeta Rusek (Tullbergiidae), and Proisotoma minuta Axelson (Isotomidae). One of these, D. (D.) cebennaria, is described. Additionally, two new indigenous species, Mesaphorura macrochaeta Rusek and Proisotoma minuta Axelson, are also recorded. The total number of Collembola species now known from the island is 14, comprised of eight native species and six non-indigenous species. This number of non-indigenous species recorded at Deception Island compares with only a single non-indigenous springtail recorded at any other maritime or continental Antarctic location. The reason underlying this high level of occurrence of non-indigenous species on Deception Island is likely to be a combination of the island's high level of human visitation and the presence of relatively benign terrestrial habitats associated with areas of geothermal activity. Two of the new records represent species recently assessed as being of the highest risk to become invaders in the less extreme environments of the subantarctic, thereby emphasising the importance and urgency of adopting and applying effective biosecurity measures to protect the unique and vulnerable ecosystems of this region. Also documented are the impacts on the soil fauna of the island from human trampling, which drastically reduced densities of both native and non-indigenous species to 1% of the abundance typical of non-trampled sites. PMID:23438196

  19. Global Collembola on Deception Island

    PubMed Central

    Greenslade, Penelope; Potapov, Mikhail; Russell, David; Convey, Peter

    2012-01-01

    Three new non-indigenous springtail species are recorded in recent collections made on Deception Island, South Shetland Islands, maritime Antarctic: Deuteraphorura (Deuteraphorura) cebennaria (Gisin) (Collembola: Onychiuridae), Mesaphorura macrochaeta Rusek (Tullbergiidae), and Proisotoma minuta Axelson (Isotomidae). One of these, D. (D.) cebennaria, is described. Additionally, two new indigenous species, Mesaphorura macrochaeta Rusek and Proisotoma minuta Axelson, are also recorded. The total number of Collembola species now known from the island is 14, comprised of eight native species and six non-indigenous species. This number of non-indigenous species recorded at Deception Island compares with only a single non-indigenous springtail recorded at any other maritime or continental Antarctic location. The reason underlying this high level of occurrence of non-indigenous species on Deception Island is likely to be a combination of the island's high level of human visitation and the presence of relatively benign terrestrial habitats associated with areas of geothermal activity. Two of the new records represent species recently assessed as being of the highest risk to become invaders in the less extreme environments of the subantarctic, thereby emphasising the importance and urgency of adopting and applying effective biosecurity measures to protect the unique and vulnerable ecosystems of this region. Also documented are the impacts on the soil fauna of the island from human trampling, which drastically reduced densities of both native and non-indigenous species to 1% of the abundance typical of non-trampled sites. PMID:23438196

  20. Waterborne pathogens in urban watersheds.

    PubMed

    Arnone, Russell D; Walling, Joyce Perdek

    2007-03-01

    A serious concern for managers of water resources, pathogens in the urban environment easily enter waters through a number of pathways, including discharge of inadequately treated sewage, stormwater runoff, combined sewer overflows and sanitary sewer overflows. Pathogens in US ambient water bodies are regulated under the Clean Water Act (CWA), while pathogens in drinking water supplies are regulated under the Safe Drinking Water Act. Total maximum daily loads (TMDLs) are developed in accordance with CWA regulations for ambient water bodies with bacterial concentrations exceeding the water quality standard, which generally is a measure of a bacterial indicator organism. However, developing a TMDL for a supplementary indicator or pathogen is also required if a use impairment would still exist even after the water body is in compliance with the standard. This occurs because indicator organisms do not reflect the presence of pathogen contamination with complete certainty. The evaluation of pathogen indicators and summary of epidemiological studies presented are resources for those developing TMDLs to achieve water quality standards and restore water bodies to their intended uses. PMID:17402286

  1. Prevalence of vector-borne pathogens in dogs from Haiti.

    PubMed

    Starkey, Lindsay A; Newton, Kassie; Brunker, Jill; Crowdis, Kelly; Edourad, Emile Jean Pierre; Meneus, Pedro; Little, Susan E

    2016-07-15

    Canine vector-borne pathogens are common on some Caribbean islands, but survey data in Haiti are lacking. To determine the prevalence of selected vector-borne pathogens in dogs from Haiti, we tested blood samples collected from 210 owned dogs, 28 (13.3%) of which were infested with Rhipicephalus sanguineus ticks at the time of blood collection. No other tick species were identified on these dogs. A commercially available ELISA identified antibodies to Ehrlichia spp. in 69 (32.9%), antibodies to Anaplasma spp. in 37 (17.6%), and antigen of Dirofilaria immitis in 55 (26.2%); antibodies to Borrelia burgdorferi were not detected in any sample. Molecular assays of whole blood from 207 of the dogs confirmed infection with Ehrlichia canis (15; 7.2%), Anaplasma platys (13; 6.3%), D. immitis (46; 22.2%), Wolbachia spp. (45; 21.7%), Babesia vogeli (16; 7.7%), and Hepatozoon canis (40; 19.3%), but Anaplasma phagocytophilum, Babesia canis, Babesia rossi, Babesia gibsoni, Ehrlichia chaffeensis, Ehrlichia ewingii, or Hepatozoon americanum were not detected. Co-infection with two or more vector-borne pathogens was detected by serology in 42 (20.0%) dogs and by molecular assays in 22 (10.6%) dogs; one dog was co-infected with B. vogeli and E. canis as detected by PCR with D. immitis detected by serology (antigen). Overall, evidence of past or current infection with at least one vector-borne pathogen was identified in 142/210 (67.6%) dogs in this study, underscoring the common nature of these pathogens, some of which are zoonotic, in Haiti. PMID:27270383

  2. Identification of Novel Genomic Islands in Liverpool Epidemic Strain of Pseudomonas aeruginosa Using Segmentation and Clustering.

    PubMed

    Jani, Mehul; Mathee, Kalai; Azad, Rajeev K

    2016-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen implicated in a myriad of infections and a leading pathogen responsible for mortality in patients with cystic fibrosis (CF). Horizontal transfers of genes among the microorganisms living within CF patients have led to highly virulent and multi-drug resistant strains such as the Liverpool epidemic strain of P. aeruginosa, namely the LESB58 strain that has the propensity to acquire virulence and antibiotic resistance genes. Often these genes are acquired in large clusters, referred to as "genomic islands (GIs)." To decipher GIs and understand their contributions to the evolution of virulence and antibiotic resistance in P. aeruginosa LESB58, we utilized a recursive segmentation and clustering procedure, presented here as a genome-mining tool, "GEMINI." GEMINI was validated on experimentally verified islands in the LESB58 strain before examining its potential to decipher novel islands. Of the 6062 genes in P. aeruginosa LESB58, 596 genes were identified to be resident on 20 GIs of which 12 have not been previously reported. Comparative genomics provided evidence in support of our novel predictions. Furthermore, GEMINI unraveled the mosaic structure of islands that are composed of segments of likely different evolutionary origins, and demonstrated its ability to identify potential strain biomarkers. These newly found islands likely have contributed to the hyper-virulence and multidrug resistance of the Liverpool epidemic strain of P. aeruginosa.

  3. Identification of Novel Genomic Islands in Liverpool Epidemic Strain of Pseudomonas aeruginosa Using Segmentation and Clustering

    PubMed Central

    Jani, Mehul; Mathee, Kalai; Azad, Rajeev K.

    2016-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen implicated in a myriad of infections and a leading pathogen responsible for mortality in patients with cystic fibrosis (CF). Horizontal transfers of genes among the microorganisms living within CF patients have led to highly virulent and multi-drug resistant strains such as the Liverpool epidemic strain of P. aeruginosa, namely the LESB58 strain that has the propensity to acquire virulence and antibiotic resistance genes. Often these genes are acquired in large clusters, referred to as “genomic islands (GIs).” To decipher GIs and understand their contributions to the evolution of virulence and antibiotic resistance in P. aeruginosa LESB58, we utilized a recursive segmentation and clustering procedure, presented here as a genome-mining tool, “GEMINI.” GEMINI was validated on experimentally verified islands in the LESB58 strain before examining its potential to decipher novel islands. Of the 6062 genes in P. aeruginosa LESB58, 596 genes were identified to be resident on 20 GIs of which 12 have not been previously reported. Comparative genomics provided evidence in support of our novel predictions. Furthermore, GEMINI unraveled the mosaic structure of islands that are composed of segments of likely different evolutionary origins, and demonstrated its ability to identify potential strain biomarkers. These newly found islands likely have contributed to the hyper-virulence and multidrug resistance of the Liverpool epidemic strain of P. aeruginosa. PMID:27536294

  4. Identification of Novel Genomic Islands in Liverpool Epidemic Strain of Pseudomonas aeruginosa Using Segmentation and Clustering.

    PubMed

    Jani, Mehul; Mathee, Kalai; Azad, Rajeev K

    2016-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen implicated in a myriad of infections and a leading pathogen responsible for mortality in patients with cystic fibrosis (CF). Horizontal transfers of genes among the microorganisms living within CF patients have led to highly virulent and multi-drug resistant strains such as the Liverpool epidemic strain of P. aeruginosa, namely the LESB58 strain that has the propensity to acquire virulence and antibiotic resistance genes. Often these genes are acquired in large clusters, referred to as "genomic islands (GIs)." To decipher GIs and understand their contributions to the evolution of virulence and antibiotic resistance in P. aeruginosa LESB58, we utilized a recursive segmentation and clustering procedure, presented here as a genome-mining tool, "GEMINI." GEMINI was validated on experimentally verified islands in the LESB58 strain before examining its potential to decipher novel islands. Of the 6062 genes in P. aeruginosa LESB58, 596 genes were identified to be resident on 20 GIs of which 12 have not been previously reported. Comparative genomics provided evidence in support of our novel predictions. Furthermore, GEMINI unraveled the mosaic structure of islands that are composed of segments of likely different evolutionary origins, and demonstrated its ability to identify potential strain biomarkers. These newly found islands likely have contributed to the hyper-virulence and multidrug resistance of the Liverpool epidemic strain of P. aeruginosa. PMID:27536294

  5. 27 CFR 9.170 - Long Island.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Long Island. 9.170 Section... Island. (a) Name. The name of the viticultural area described in this section is “Long Island.” (b) Approved maps. The appropriate maps for determining the boundary of the Long Island viticultural area...

  6. 27 CFR 9.170 - Long Island.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Long Island. 9.170 Section... Island. (a) Name. The name of the viticultural area described in this section is “Long Island.” (b) Approved maps. The appropriate maps for determining the boundary of the Long Island viticultural area...

  7. 21 CFR 808.89 - Rhode Island.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rhode Island. 808.89 Section 808.89 Food and Drugs... and Local Exemptions § 808.89 Rhode Island. The following Rhode Island medical device requirements are... from preemption under section 521(b) of the act: Rhode Island General Laws, Section 5-49-2.1,...

  8. 27 CFR 9.170 - Long Island.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Long Island. 9.170 Section... Island. (a) Name. The name of the viticultural area described in this section is “Long Island.” (b) Approved maps. The appropriate maps for determining the boundary of the Long Island viticultural area...

  9. 21 CFR 808.89 - Rhode Island.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Rhode Island. 808.89 Section 808.89 Food and Drugs... and Local Exemptions § 808.89 Rhode Island. The following Rhode Island medical device requirements are... from preemption under section 521(b) of the act: Rhode Island General Laws, Section 5-49-2.1,...

  10. 21 CFR 808.89 - Rhode Island.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Rhode Island. 808.89 Section 808.89 Food and Drugs... and Local Exemptions § 808.89 Rhode Island. The following Rhode Island medical device requirements are... from preemption under section 521(b) of the act: Rhode Island General Laws, Section 5-49-2.1,...

  11. 27 CFR 9.170 - Long Island.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Long Island. 9.170 Section... Island. (a) Name. The name of the viticultural area described in this section is “Long Island.” (b) Approved maps. The appropriate maps for determining the boundary of the Long Island viticultural area...

  12. 21 CFR 808.89 - Rhode Island.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Rhode Island. 808.89 Section 808.89 Food and Drugs... and Local Exemptions § 808.89 Rhode Island. The following Rhode Island medical device requirements are... from preemption under section 521(b) of the act: Rhode Island General Laws, Section 5-49-2.1,...

  13. 27 CFR 9.170 - Long Island.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Long Island. 9.170 Section... Island. (a) Name. The name of the viticultural area described in this section is “Long Island.” (b) Approved maps. The appropriate maps for determining the boundary of the Long Island viticultural area...

  14. 21 CFR 808.89 - Rhode Island.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Rhode Island. 808.89 Section 808.89 Food and Drugs... and Local Exemptions § 808.89 Rhode Island. The following Rhode Island medical device requirements are... from preemption under section 521(b) of the act: Rhode Island General Laws, Section 5-49-2.1,...

  15. Stroke and Native Hawaiians/Pacific Islanders

    MedlinePlus

    ... Other Pacific Islander > Stroke Stroke and Native Hawaiians/Pacific Islanders Native Hawaiians/Pacific Islanders were four times more likely than non- ... a stroke in 2010. In general, Native Hawaiian/Pacific Islander adults have developed several of the high ...

  16. [Relationships between island characteristics and arthropod diversity in Thousand-Island Lake].

    PubMed

    Ren, Li-jun; Xu, Zhi-hong; Lu, Jian-bo; Zhao, Gai; Zhang, Qun

    2009-09-01

    In April, May, August, and October 2006, grid-based sampling method was adopted to investigate the diversity and abundance of arthropods on 50 islands in the Thousand-island Lake, with the effects of island area, island altitude, island shape, inter-island distance, and island-mainland distance on arthropod species richness analyzed. With the increase of island area, the richness of total arthropod species and that of the arthropod species with high- and low- dispersal ability all increased, and the relationships between island area and arthropod species richness corresponded to the classical island biogeography model. The island area, island altitude, and island shape had comprehensive effects on the arthropod species richness, while inter-island distance and island-mainland distance had less effects. The richness of total arthropod species had a significant positive correlation with island altitude and island shape, that of the arthropod species with high- dispersal ability was significantly positively correlated with island area and island altitude, while no significant relationship was observed between the richness of arthropod species with low-dispersal ability and the island characteristics.

  17. 46 CFR 7.80 - Tybee Island, GA to St. Simons Island, GA.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Tybee Island, GA to St. Simons Island, GA. 7.80 Section... BOUNDARY LINES Atlantic Coast § 7.80 Tybee Island, GA to St. Simons Island, GA. (a) A line drawn from the southernmost extremity of Savannah Beach on Tybee Island 255° true across Tybee Inlet to the shore of...

  18. 46 CFR 7.80 - Tybee Island, GA to St. Simons Island, GA.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Tybee Island, GA to St. Simons Island, GA. 7.80 Section... BOUNDARY LINES Atlantic Coast § 7.80 Tybee Island, GA to St. Simons Island, GA. (a) A line drawn from the southernmost extremity of Savannah Beach on Tybee Island 255° true across Tybee Inlet to the shore of...

  19. 46 CFR 7.80 - Tybee Island, GA to St. Simons Island, GA.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Tybee Island, GA to St. Simons Island, GA. 7.80 Section... BOUNDARY LINES Atlantic Coast § 7.80 Tybee Island, GA to St. Simons Island, GA. (a) A line drawn from the southernmost extremity of Savannah Beach on Tybee Island 255° true across Tybee Inlet to the shore of...

  20. 46 CFR 7.80 - Tybee Island, GA to St. Simons Island, GA.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Tybee Island, GA to St. Simons Island, GA. 7.80 Section... BOUNDARY LINES Atlantic Coast § 7.80 Tybee Island, GA to St. Simons Island, GA. (a) A line drawn from the southernmost extremity of Savannah Beach on Tybee Island 255° true across Tybee Inlet to the shore of...

  1. 46 CFR 7.80 - Tybee Island, GA to St. Simons Island, GA.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Tybee Island, GA to St. Simons Island, GA. 7.80 Section... BOUNDARY LINES Atlantic Coast § 7.80 Tybee Island, GA to St. Simons Island, GA. (a) A line drawn from the southernmost extremity of Savannah Beach on Tybee Island 255° true across Tybee Inlet to the shore of...

  2. Mobilization of Genomic Islands of Staphylococcus aureus by Temperate Bacteriophage.

    PubMed

    Moon, Bo Youn; Park, Joo Youn; Robinson, D Ashley; Thomas, Jonathan C; Park, Yong Ho; Thornton, Justin A; Seo, Keun Seok

    2016-01-01

    The virulence of Staphylococcus aureus, in both human and animal hosts, is largely influenced by the acquisition of mobile genetic elements (MGEs). Most S. aureus strains carry a variety of MGEs, including three genomic islands (νSaα, νSaβ, νSaγ) that are diverse in virulence gene content but conserved within strain lineages. Although the mobilization of pathogenicity islands, phages and plasmids has been well studied, the mobilization of genomic islands is poorly understood. We previously demonstrated the mobilization of νSaβ by the adjacent temperate bacteriophage ϕSaBov from strain RF122. In this study, we demonstrate that ϕSaBov mediates the mobilization of νSaα and νSaγ, which are located remotely from ϕSaBov, mostly to recipient strains belonging to ST151. Phage DNA sequence analysis revealed that chromosomal DNA excision events from RF122 were highly specific to MGEs, suggesting sequence-specific DNA excision and packaging events rather than generalized transduction by a temperate phage. Disruption of the int gene in ϕSaBov did not affect phage DNA excision, packaging, and integration events. However, disruption of the terL gene completely abolished phage DNA packing events, suggesting that the primary function of temperate phage in the transfer of genomic islands is to allow for phage DNA packaging by TerL and that transducing phage particles are the actual vehicle for transfer. These results extend our understanding of the important role of bacteriophage in the horizontal transfer and evolution of genomic islands in S. aureus.

  3. Mobilization of Genomic Islands of Staphylococcus aureus by Temperate Bacteriophage

    PubMed Central

    Moon, Bo Youn; Park, Joo Youn; Robinson, D. Ashley; Thomas, Jonathan C.; Park, Yong Ho; Thornton, Justin A.; Seo, Keun Seok

    2016-01-01

    The virulence of Staphylococcus aureus, in both human and animal hosts, is largely influenced by the acquisition of mobile genetic elements (MGEs). Most S. aureus strains carry a variety of MGEs, including three genomic islands (νSaα, νSaβ, νSaγ) that are diverse in virulence gene content but conserved within strain lineages. Although the mobilization of pathogenicity islands, phages and plasmids has been well studied, the mobilization of genomic islands is poorly understood. We previously demonstrated the mobilization of νSaβ by the adjacent temperate bacteriophage ϕSaBov from strain RF122. In this study, we demonstrate that ϕSaBov mediates the mobilization of νSaα and νSaγ, which are located remotely from ϕSaBov, mostly to recipient strains belonging to ST151. Phage DNA sequence analysis revealed that chromosomal DNA excision events from RF122 were highly specific to MGEs, suggesting sequence-specific DNA excision and packaging events rather than generalized transduction by a temperate phage. Disruption of the int gene in ϕSaBov did not affect phage DNA excision, packaging, and integration events. However, disruption of the terL gene completely abolished phage DNA packing events, suggesting that the primary function of temperate phage in the transfer of genomic islands is to allow for phage DNA packaging by TerL and that transducing phage particles are the actual vehicle for transfer. These results extend our understanding of the important role of bacteriophage in the horizontal transfer and evolution of genomic islands in S. aureus. PMID:26953931

  4. Postgenomic analysis of bacterial pathogens repertoire reveals genome reduction rather than virulence factors.

    PubMed

    Merhej, Vicky; Georgiades, Kalliopi; Raoult, Didier

    2013-07-01

    In the pregenomic era, the acquisition of pathogenicity islands via horizontal transfer was proposed as a major mechanism in pathogen evolution. Much effort has been expended to look for the contiguous blocks of virulence genes that are present in pathogenic bacteria, but absent in closely related species that are nonpathogenic. However, some of these virulence factors were found in nonpathogenic bacteria. Moreover, and contrary to expectation, pathogenic bacteria were found to lack genes (antivirulence genes) that are characteristic of nonpathogenic bacteria. The availability of complete genome sequences has led to a new era of pathogen research. Comparisons of genomes have shown that the most pathogenic bacteria have reduced genomes, with less ribosomal RNA and unorganized operons; they lack transcriptional regulators but have more genes that encode protein toxins, toxin-antitoxin (TA) modules, and proteins for DNA replication and repair, when compared with less pathogenic close relatives. These findings questioned the paradigm of virulence by gene acquisition and put forward the notion of genomic repertoire of virulence.

  5. Genetic characterization of highly pathogenic H5 influenza viruses from poultry in Taiwan, 2015.

    PubMed

    Huang, Pei-Yu; Lee, Chang-Chun David; Yip, Chun-Hung; Cheung, Chung-Lam; Yu, Guangchuang; Lam, Tommy Tsan-Yuk; Smith, David K; Zhu, Huachen; Guan, Yi

    2016-03-01

    Phylogenetic analysis of the highly pathogenic avian influenza (HPAI) H5 viruses causing recent outbreaks in Taiwan showed that they belonged to the Asian HPAI H5 lineage, clade 2.3.4.4 viruses, and were apparently introduced by migratory birds. These viruses reassorted with Eurasian influenza gene pool viruses and formed five genotypic variants. As Taiwan has a similar influenza ecosystem to southern China, the HPAI H5 lineage could become established and enzootic in the island.

  6. Mosquitoes of Guam and the Northern Marianas: distribution, checklists, and notes on mosquito-borne pathogens.

    PubMed

    Rueda, Leopoldo M; Pecor, James E; Reeves, Will K; Wolf, Stephen P; Nunn, Peter V; Rabago, Rosanna Y; Gutierrez, Teresa L; Debboun, Mustapha

    2011-01-01

    This report includes the distribution records and updated checklists of the mosquitoes known to occur in Guam and nearby selected islands (ie, Saipan, Tinian, Rota), based on our field collections from various localities during 2010, published reports, and accessioned specimens deposited in the US National Museum of Natural History, Smithsonian Institution, Washington, DC. The status of common and potential mosquito vectors and their borne-pathogens are also noted.

  7. The Three Mile Island Disaster.

    ERIC Educational Resources Information Center

    Crosby, Emeral

    1980-01-01

    For the past decade, education has been experiencing meltdown, explosions, radiation leaks, heat pollution, and management crises, just like the Three Mile Island disaster. This article offers suggestions on how to deal with these problems. (Author/LD)

  8. Synthesizing knowledge of ocean islands

    NASA Astrophysics Data System (ADS)

    Jefferson, Anne J.; Lees, Jonathan M.; McClinton, Tim

    2011-11-01

    AGU Chapman Conference on the Galápagos as a Laboratory for the Earth Sciences; Puerto Ayora, Galápagos, Ecuador, 25-30 July 2011 An inspiration for Darwin's theory of evolution, the Galápagos Islands and surrounding waters are a natural laboratory for a wide range of Earth science topics. The Galápagos are perfectly situated for geophysical and geochemical investigations of deep-Earth processes at a hot spot, and proximity to a spreading center allows exploration of hot spot-ridge interactions. Several highly active volcanoes show rapid deformation facilitating investigation of melt transport paths and volcanic structure. The islands exhibit a range of ages, eruptive styles, and climatic zones that allow analysis of hydrogeologic and geomorphic processes. The Galápagos Islands are a World Heritage Site and are an ideal setting for developing an integrated biological and geological understanding of ocean island evolution.

  9. Upolu Island, Western Samoa

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Island nations in the South Pacific Ocean experience natural disasters associated with typhoons, and with their proximity to the Pacific Ocean's 'Ring of Fire.' This radar image shows the western end of the island of Upolu in the nation of Western Samoa. Disaster managers use digital elevation models (DEMs) generated from radar data to assist in research toward disaster mitigation and management. Geologists also use DEM data of volcanic features, such as the circular craters in this image, to study eruption rates and volumes, and volcanic landform evolution.

    Black areas near the top of the image are areas where steep topography causes holes in the data; these holes can be filled in by collecting data at other look directions. Color represents topography and intensity represents across-section of the radar backscatter. Since rough areas return more of the incident signal, they appear brighter on the image than relatively smooth areas, such as the ocean surface at the top of the image.

    This image was acquired by the AIRborne Synthetic Aperture (AIRSAR) radar instrument aboard a DC-8 aircraft operated out of NASA's Dryden Flight Research Center. AIRSAR collects fully polarimetric data at three wavelengths; C-band (0.057 meter), L-band (0.25 meter) and P-band (0.68 meter). AIRSAR also collects cross-track and along track interferometric data that results in topographic measurements and motion detection, respectively.

    This image was collected during the Pacific Rim mission, a three-month mission from July to October 2000 that collected data at over 200 sites in eighteen countries and territories around the Pacific Rim. AIRSAR is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise,Washington, D.C.

    Size: 10 km (6.2 miles) x 10 km (6.2 miles) Location: 14.02 deg. North lat., 171.52 deg. West Orientation: North at top Date Acquired: August 10, 2000

  10. Upolu Island, Western Samoa

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Island nations in the South Pacific Ocean experience natural disasters associated with typhoons, and with their proximity to the Pacific Ocean's 'Ring of Fire.' This radar image shows most of the northern coast of the island of Upolu in the nation of Western Samoa. Disaster managers use digital elevation models (DEMs) generated from radar data to assist in research toward disaster mitigation and management. Geologists also use DEM data of volcanic features, such as the line of circular craters in this image, to study eruption rates and volumes, and volcanic landform evolution. The capital of Western Samoa, Apia, is in the lower left of the image.

    Angular black areas in the image are areas where steep topography causes holes in the data; these holes can be filled in by collecting data at other look directions. Color represents topography and intensity represents across-section of the radar backscatter. Since rough areas return more of the incident signal, they appear brighter on the image than relatively smooth areas, such as the ocean surface , along the left side of the image.

    This image was acquired by the AIRborne Synthetic Aperture (AIRSAR) radar instrument aboard a DC-8 aircraft operated out of NASA's Dryden Flight Research Center. AIRSAR collects fully polarimetric data at three wavelengths; C-band (0.057 meter), L-band (0.25 meter) and P-band (0.68 meter). AIRSAR also collects cross-track and along track interferometric data that results in topographic measurements and motion detection, respectively.

    This image was collected during the Pacific Rim mission, a three-month mission from July to October 2000 that collected data at over 200 sites in eighteen countries and territories around the Pacific Rim. AIRSAR is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise,Washington, D.C.

    Size: 10 km (6.2 miles) x 63 km (37.3 miles) Location: 14.16 deg. North lat., 171.75 deg. West Orientation: North towards

  11. Characterization of Pathogenicity, Virulence and Host-Pathogen Interractions

    SciTech Connect

    Krishnan, A; Folta, P

    2006-07-27

    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

  12. Host-specificity of Salmonella enterica serovar Gallinarum: insights from comparative genomics.

    PubMed

    Eswarappa, Sandeepa M; Janice, Jessin; Balasundaram, Sudhagar V; Dixit, Narendra M; Chakravortty, Dipshikha

    2009-07-01

    In this study, we have identified the possible genetic factors responsible for fowl-adaptation of Salmonella entericaserovar Gallinarum (S. Gallinarum). By comparing the genes related to Salmonella pathogenicity islands (SPI) of S. Gallinarum with those of Salmonella entericaserovar Enteritidis (S. Enteritidis) we have identified twenty-four positively selected genes. Our results suggest that the genes encoding the structural components of SPI-2 encoded type three secretion apparatus (TTSS) and the effector proteins that are secreted via SPI-1 encoded TTSS have evolved under positive selection pressure in these serovars. We propose that these positively selected genes play important roles in conferring different host-specificities to S. Gallinarum and S. Enteritidis.

  13. Eco-geomorphic processes that maintain a small coral reef island: Ballast Island in the Ryukyu Islands, Japan

    NASA Astrophysics Data System (ADS)

    Kayanne, Hajime; Aoki, Kenji; Suzuki, Takuya; Hongo, Chuki; Yamano, Hiroya; Ide, Yoichi; Iwatsuka, Yuudai; Takahashi, Kenya; Katayama, Hiroyuki; Sekimoto, Tsunehiro; Isobe, Masahiko

    2016-10-01

    Landform changes in Ballast Island, a small coral reef island in the Ryukyu Islands, were investigated by remote sensing analysis and a field survey. The area of the island almost doubled after a mass coral bleaching event in 1998. Coral branches generated by the mass mortality and broken by waves were delivered and stocked on a reef flat and accumulated to expand the area of the island. In 2012 high waves generated by typhoons also changed the island's topography. Overall, the island moved in the downdrift direction of the higher waves. Waves impacting both sides of the island piled up a large volume of coral gravels above the high-tide level. Eco-geomorphic processes, including a supply of calcareous materials from the corals on the same reef especially during stormy wave conditions, were key factors in maintaining the dynamic topographic features of this small coral reef island.

  14. Compositions and methods for pathogen transport

    DOEpatents

    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.

  15. Pathogen evolution and the immunological niche

    PubMed Central

    Cobey, Sarah

    2014-01-01

    Host immunity is a major driver of pathogen evolution and thus a major determinant of pathogen diversity. Explanations for pathogen diversity traditionally assume simple interactions between pathogens and the immune system, a view encapsulated by the susceptible–infected–recovered (SIR) model. However, there is growing evidence that the complexity of many host–pathogen interactions is dynamically important. This revised perspective requires broadening the definition of a pathogen's immunological phenotype, or what can be thought of as its immunological niche. After reviewing evidence that interactions between pathogens and host immunity drive much of pathogen evolution, I introduce the concept of a pathogen's immunological phenotype. Models that depart from the SIR paradigm demonstrate the utility of this perspective and show that it is particularly useful in understanding vaccine-induced evolution. This paper highlights questions in immunology, evolution, and ecology that must be answered to advance theories of pathogen diversity. PMID:25040161

  16. Yersinia enterocolitica palearctica serobiotype O:3/4 - a successful group of emerging zoonotic pathogens

    PubMed Central

    2011-01-01

    Background High-pathogenic Y. enterocolitica ssp. enterocolitica caused several human outbreaks in Northern America. In contrast, low pathogenic Y. enterocolitica ssp. palearctica serobiotype O:3/4 is responsible for sporadic cases worldwide with asymptomatic pigs being the main source of infection. Genomes of three Y. enterocolitica ssp. palearctica serobiotype O:3/4 human isolates (including the completely sequenced Y11 German DSMZ type strain) were compared to the high-pathogenic Y. enterocolitica ssp. enterocolitica 8081 O:8/1B to address the peculiarities of the O:3/4 group. Results Most high-pathogenicity-associated determinants of Y. enterocolitica ssp. enterocolitica (like the High-Pathogenicity Island, yts1 type 2 and ysa type 3 secretion systems) are absent in Y. enterocolitica ssp. palearctica serobiotype O:3/4 genomes. On the other hand they possess alternative putative virulence and fitness factors, such as a different ysp type 3 secretion system, an RtxA-like and insecticidal toxins, and a N-acetyl-galactosamine (GalNAc) PTS system (aga-operon). Horizontal acquisition of two prophages and a tRNA-Asn-associated GIYep-01 genomic island might also influence the Y. enterocolitica ssp. palearctica serobiotype O:3/4 pathoadaptation. We demonstrated recombination activity of the PhiYep-3 prophage and the GIYep-01 island and the ability of the aga-operon to support the growth of the Y. enterocolitica ssp. enterocolitica O:8/1B on GalNAc. Conclusions Y. enterocolitica ssp. palearctica serobiotype O:3/4 experienced a shift to an alternative patchwork of virulence and fitness determinants that might play a significant role in its host pathoadaptation and successful worldwide dissemination. PMID:21733159

  17. Infectious pathogens and bronchiolitis outcomes.

    PubMed

    Hasegawa, Kohei; Mansbach, Jonathan M; Camargo, Carlos A

    2014-07-01

    Bronchiolitis is a common early childhood illness and an important cause of morbidity, it is the number one cause of hospitalization among US infants. Bronchiolitis is also an active area of research, and recent studies have advanced our understanding of this illness. Although it has long been the conventional wisdom that the infectious etiology of bronchiolitis does not affect outcomes, a growing number of studies have linked specific pathogens of bronchiolitis (e.g., rhinovirus) to short- and long-term outcomes, such as future risk of developing asthma. The authors review the advent of molecular diagnostic techniques that have demonstrated diverse pathogens in bronchiolitis, and they review recent studies on the complex link between infectious pathogens of bronchiolitis and the development of childhood asthma.

  18. The Main Aeromonas Pathogenic Factors

    PubMed Central

    Tomás, J. M.

    2012-01-01

    The members of the Aeromonas genus are ubiquitous, water-borne bacteria. They have been isolated from marine waters, rivers, lakes, swamps, sediments, chlorine water, water distribution systems, drinking water and residual waters; different types of food, such as meat, fish, seafood, vegetables, and processed foods. Aeromonas strains are predominantly pathogenic to poikilothermic animals, and the mesophilic strains are emerging as important pathogens in humans, causing a variety of extraintestinal and systemic infections as well as gastrointestinal infections. The most commonly described disease caused by Aeromonas is the gastroenteritis; however, no adequate animal model is available to reproduce this illness caused by Aeromonas. The main pathogenic factors associated with Aeromonas are: surface polysaccharides (capsule, lipopolysaccharide, and glucan), S-layers, iron-binding systems, exotoxins and extracellular enzymes, secretion systems, fimbriae and other nonfilamentous adhesins, motility and flagella. PMID:23724321

  19. Proteomics of Plant Pathogenic Fungi

    PubMed Central

    González-Fernández, Raquel; Prats, Elena; Jorrín-Novo, Jesús V.

    2010-01-01

    Plant pathogenic fungi cause important yield losses in crops. In order to develop efficient and environmental friendly crop protection strategies, molecular studies of the fungal biological cycle, virulence factors, and interaction with its host are necessary. For that reason, several approaches have been performed using both classical genetic, cell biology, and biochemistry and the modern, holistic, and high-throughput, omic techniques. This work briefly overviews the tools available for studying Plant Pathogenic Fungi and is amply focused on MS-based Proteomics analysis, based on original papers published up to December 2009. At a methodological level, different steps in a proteomic workflow experiment are discussed. Separate sections are devoted to fungal descriptive (intracellular, subcellular, extracellular) and differential expression proteomics and interactomics. From the work published we can conclude that Proteomics, in combination with other techniques, constitutes a powerful tool for providing important information about pathogenicity and virulence factors, thus opening up new possibilities for crop disease diagnosis and crop protection. PMID:20589070

  20. 46 CFR 7.85 - St. Simons Island, GA to Little Talbot Island, FL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false St. Simons Island, GA to Little Talbot Island, FL. 7.85... BOUNDARY LINES Atlantic Coast § 7.85 St. Simons Island, GA to Little Talbot Island, FL. (a) A line drawn... Island Light. (b) A line drawn from the southernmost extremity of Amelia Island to latitude 30°29.4′...

  1. 46 CFR 7.85 - St. Simons Island, GA to Little Talbot Island, FL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false St. Simons Island, GA to Little Talbot Island, FL. 7.85... BOUNDARY LINES Atlantic Coast § 7.85 St. Simons Island, GA to Little Talbot Island, FL. (a) A line drawn... Island Light. (b) A line drawn from the southernmost extremity of Amelia Island to latitude 30°29.4′...

  2. 46 CFR 7.85 - St. Simons Island, GA to Little Talbot Island, FL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false St. Simons Island, GA to Little Talbot Island, FL. 7.85... BOUNDARY LINES Atlantic Coast § 7.85 St. Simons Island, GA to Little Talbot Island, FL. (a) A line drawn... Island Light. (b) A line drawn from the southernmost extremity of Amelia Island to latitude 30°29.4′...

  3. 46 CFR 7.85 - St. Simons Island, GA to Little Talbot Island, FL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false St. Simons Island, GA to Little Talbot Island, FL. 7.85... BOUNDARY LINES Atlantic Coast § 7.85 St. Simons Island, GA to Little Talbot Island, FL. (a) A line drawn... Island Light. (b) A line drawn from the southernmost extremity of Amelia Island to latitude 30°29.4′...

  4. 46 CFR 7.85 - St. Simons Island, GA to Little Talbot Island, FL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false St. Simons Island, GA to Little Talbot Island, FL. 7.85... BOUNDARY LINES Atlantic Coast § 7.85 St. Simons Island, GA to Little Talbot Island, FL. (a) A line drawn... Island Light. (b) A line drawn from the southernmost extremity of Amelia Island to latitude 30°29.4′...

  5. Xylella Genomics and Bacterial Pathogenicity to Plants

    PubMed Central

    Dow, J. M.

    2000-01-01

    Xylella fastidiosa, a pathogen of citrus, is the first plant pathogenic bacterium for which the complete genome sequence has been published. Inspection of the sequence reveals high relatedness to many genes of other pathogens, notably Xanthomonas campestris. Based on this, we suggest that Xylella possesses certain easily testable properties that contribute to pathogenicity. We also present some general considerations for deriving information on pathogenicity from bacterial genomics. PMID:11119303

  6. OUTERBRIDGE CROSSING BRIDGE IN PERSPECTIVE, STATEN ISLAND ON RIGHT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OUTERBRIDGE CROSSING BRIDGE IN PERSPECTIVE, STATEN ISLAND ON RIGHT - Outerbridge Crossing Bridge, Spanning Arthur Kill from New Jersey to Staten Island, Staten Island (subdivision), Richmond County, NY

  7. New trends in emerging pathogens.

    PubMed

    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

  8. New trends in emerging pathogens.

    PubMed

    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

  9. Pathogenic rickettsiae as bioterrorism agents.

    PubMed

    Azad, Abdu F

    2007-07-15

    Because of their unique biological characteristics, such as environmental stability, small size, aerosol transmission, persistence in infected hosts, low infectious dose, and high associated morbidity and mortality, Rickettsia prowazekii and Coxiella burnetii have been weaponized. These biological attributes would make the pathogenic rickettsiae desirable bioterrorism agents. However, production of highly purified, virulent, weapon-quality rickettsiae is a daunting task that requires expertise and elaborate, state-of-the art laboratory procedures to retain rickettsial survival and virulence. Another drawback to developing rickettsial pathogens as biological weapons is their lack of direct transmission from host to host and the availability of very effective therapeutic countermeasures against these obligate intracellular bacteria.

  10. Bryophytes from Simeonof Island in the Shumagin Islands, southwestern Alaska

    USGS Publications Warehouse

    Schofield, W.B.; Talbot, S. S.; Talbot, S.L.

    2004-01-01

    Simeonof Island is located south of the Alaska Peninsula in the hyperoceanic sector of the middle boreal subzone. We examined the bryoflora of Simeonof Island to determine species composition in an area where no previous collections had been reported. This field study was conducted in sites selected to represent the spectrum of environmental variation within Simeonof Island. Data were analyzed using published reports to compare bryophyte distribution patterns at three levels, the Northern Hemisphere, North America, and Alaska. A total of 271 bryophytes were identified: 202 mosses and 69 liverworts. The annotated list of species for Simeonof Island expands the known range for many species and fills distribution gaps within Hulte??n's Western Pacific Coast district. Maps and notes on the distribution of 14 significant distribution records are presented. Compared with bryophyte distribution in the Northern Hemisphere, the bryoflora of Simeonof Island primarily includes taxa of boreal (55%), temperate (20%), arctic (10%), and cosmopolitan (8%) distribution; 6% of the moss flora are western North America endemics. A description of the bryophytes present in the vegetation and habitat types is provided as is a quantitative analysis of the most frequently occurring bryophytes in crowberry heath.

  11. Mapping the Regulatory Network for Salmonella enterica Serovar Typhimurium Invasion

    PubMed Central

    Smith, Carol; Stringer, Anne M.; Mao, Chunhong; Palumbo, Michael J.

    2016-01-01

    ABSTRACT Salmonella enterica pathogenicity island 1 (SPI-1) encodes proteins required for invasion of gut epithelial cells. The timing of invasion is tightly controlled by a complex regulatory network. The transcription factor (TF) HilD is the master regulator of this process and senses environmental signals associated with invasion. HilD activates transcription of genes within and outside SPI-1, including six other TFs. Thus, the transcriptional program associated with host cell invasion is controlled by at least 7 TFs. However, very few of the regulatory targets are known for these TFs, and the extent of the regulatory network is unclear. In this study, we used complementary genomic approaches to map the direct regulatory targets of all 7 TFs. Our data reveal a highly complex and interconnected network that includes many previously undescribed regulatory targets. Moreover, the network extends well beyond the 7 TFs, due to the inclusion of many additional TFs and noncoding RNAs. By comparing gene expression profiles of regulatory targets for the 7 TFs, we identified many uncharacterized genes that are likely to play direct roles in invasion. We also uncovered cross talk between SPI-1 regulation and other regulatory pathways, which, in turn, identified gene clusters that likely share related functions. Our data are freely available through an intuitive online browser and represent a valuable resource for the bacterial research community. PMID:27601571

  12. ClpP deletion causes attenuation of Salmonella Typhimurium virulence through mis-regulation of RpoS and indirect control of CsrA and the SPI genes.

    PubMed

    Knudsen, Gitte M; Olsen, John E; Aabo, Søren; Barrow, Paul; Rychlik, Ivan; Thomsen, Line E

    2013-07-01

    Salmonella enterica serovar Typhimurium requires the type III secretion system encoded by Salmonella pathogenicity island 1 (SPI1) and controlled by the master regulator, HilA, to penetrate the intestinal epithelium. Numerous regulators affect virulence through influence on this system, including the proteolytic component ClpP, the stationary phase regulator RpoS and the carbon-storage regulator CsrA. However, the mechanism behind the ClpP regulation is not fully understood. To elucidate this we examined differentially expressed genes in a ΔclpP mutant compared with WT using global transcriptomic analysis. SPI1 and SPI4 virulence genes were significantly downregulated in the ΔclpP mutant, whereas several RpoS-dependent genes and the fliC gene encoding flagellin were upregulated. While the ΔclpP mutant was attenuated in cell invasion, this attenuation was not present in a ΔclpP/rpoS : : amp double mutant, suggesting the repression of invasion was directed through RpoS. The expression of the csrA virulence regulator was increased in the ΔclpP mutant and decreased in the rpoS : : amp and ΔclpP/rpoS : : amp mutants, indicating that ClpP affects the csrA expression level as well. Thus, this study suggests that ClpP affects SPI1 expression and thereby virulence indirectly through its regulation of both RpoS and CsrA.

  13. Evidence for regular ongoing introductions of mosquito disease vectors into the Galápagos Islands

    PubMed Central

    Bataille, Arnaud; Cunningham, Andrew A.; Cedeño, Virna; Cruz, Marilyn; Eastwood, Gillian; Fonseca, Dina M.; Causton, Charlotte E.; Azuero, Ronal; Loayza, Jose; Martinez, Jose D. Cruz; Goodman, Simon J.

    2009-01-01

    Wildlife on isolated oceanic islands is highly susceptible to the introduction of pathogens. The recent establishment in the Galápagos Islands of the mosquito Culex quinquefasciatus, a vector for diseases such as avian malaria and West Nile fever, is considered a serious risk factor for the archipelago's endemic fauna. Here we present evidence from the monitoring of aeroplanes and genetic analysis that C. quinquefasciatus is regularly introduced via aircraft into the Galápagos Archipelago. Genetic population structure and admixture analysis demonstrates that these mosquitoes breed with, and integrate successfully into, already-established populations of C. quinquefasciatus in the Galápagos, and that there is ongoing movement of mosquitoes between islands. Tourist cruise boats and inter-island boat services are the most likely mechanism for transporting Culex mosquitoes between islands. Such anthropogenic mosquito movements increase the risk of the introduction of mosquito-borne diseases novel to Galápagos and their subsequent widespread dissemination across the archipelago. Failure to implement and maintain measures to prevent the human-assisted transport of mosquitoes to and among the islands could have catastrophic consequences for the endemic wildlife of Galápagos. PMID:19675009

  14. Fossil mammoths from Santa Cruz Island, California

    NASA Astrophysics Data System (ADS)

    Cushing, John; Daily, Marla; Noble, Elmer; Louise Roth, V.; Wenner, Adrian

    1984-05-01

    Mammoth remains on Santa Cruz Island, one of the four Northern Channel Islands of California, are very sparse, in marked contrast to those reported from Santa Rosa and San Miguel Islands of the same island group. A probable major reason for this scarcity is that Quaternary deposits are greatly restricted on Santa Cruz Island. It is proposed, contrary to popular opinion, that fossils found on Santa Cruz Island were derived from animals which died on the island, and were not transported there by humans. Reasons for this conclusion are that the size and geological context of the fossils are similar to those of the largest mammoth fossils of Santa Rosa Island, and that, in spite of extensive investigations by many persons, mammoth remains have not been found in middens, either on the islands or on the adjacent mainland.

  15. Thermally Dimorphic Human Fungal Pathogens--Polyphyletic Pathogens with a Convergent Pathogenicity Trait.

    PubMed

    Sil, Anita; Andrianopoulos, Alex

    2015-08-01

    Fungi are adept at changing their cell shape and developmental program in response to signals in their surroundings. Here we focus on a group of evolutionarily related fungal pathogens of humans known as the thermally dimorphic fungi. These organisms grow in a hyphal form in the environment but shift their morphology drastically within a mammalian host. Temperature is one of the main host signals that initiates their conversion to the "host" form and is sufficient in the laboratory to trigger establishment of this host-adapted developmental program. Here we discuss the major human pathogens in this group, which are Blastomyces dermatiditis, Coccidioides immitis/posadasii, Histoplasma capsulatum, Paracoccidioides brasiliensis/lutzii, Sporothrix schenckii, and Talaromyces marneffei (formerly known as Penicillium marneffei). The majority of these organisms are primary pathogens, with the ability to cause disease in healthy humans who encounter them in endemic areas. PMID:25384771

  16. Perspective View of Umnak Island, Aleutian Islands, Alaska (#1)

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image is a perspective view of Umnak Island, one of Alaska's Aleutian Islands. The active Okmok volcano appears in the center of the island.

    The image was created by draping a Landsat 7 Thematic Mapper image over a digital elevation mosaic derived from Airsar data.

    This work was conducted as part of a NASA-funded Alaska Digital Elevation Model Project at the Alaska Synthetic Aperture Radar Facility (ASF) at the University of Alaska Geophysical Institute in Fairbanks, Alaska.

    Airsar collected the Alaska data as part of its PacRim 2000 Mission, which took the instrument to French Polynesia, American and Western Samoa, Fiji, New Zealand, Australia, New Guinea, Indonesia, Malaysia, Cambodia, Philippines, Taiwan, South Korea, Japan, Northern Marianas, Guam, Palau, Hawaii and Alaska. Airsar, part of NASA's Airborne Science Program, is managed for NASA's Earth Science Enterprise by JPL. JPL is a division of the California Institute of Technology in Pasadena.

  17. Perspective View of Umnak Island, Aleutian Islands, Alaska (#2)

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image is a perspective view of Umnak Island, one of Alaska's Aleutian Islands. The active Okmok volcano appears in the center of the island.

    The image was created by draping a Landsat 7 Thematic Mapper image over a digital elevation mosaic derived from Airsar data.

    This work was conducted as part of a NASA-funded Alaska Digital Elevation Model Project at the Alaska Synthetic Aperture Radar Facility (ASF) at the University of Alaska Geophysical Institute in Fairbanks, Alaska.

    Airsar collected the Alaska data as part of its PacRim 2000 Mission, which took the instrument to French Polynesia, American and Western Samoa, Fiji, New Zealand, Australia, New Guinea, Indonesia, Malaysia, Cambodia, Philippines, Taiwan, South Korea, Japan, Northern Marianas, Guam, Palau, Hawaii and Alaska. Airsar, part of NASA's Airborne Science Program, is managed for NASA's Earth Science Enterprise by JPL. JPL is a division of the California Institute of Technology in Pasadena.

  18. One million served: Rhode Island`s recycling facility

    SciTech Connect

    Malloy, M.G.

    1997-11-01

    Rhode Island`s landfill and adjacent materials recovery facility (MRF) in Johnston, both owned by the quasi-public Rhode Island Resource Recovery Corp. (RIRRC, Johnston), serve the entire state. The $12-million recycling facility was built in 1989 next to the state`s sole landfill, the Central Landfill, which accepts only in-state trash. The MRF is operated for RIRRC by New England CRInc. (Hampton, N.H.), a unit of Waste Management, Inc. (WMI, Oak Brook, Ill.). It handles a wide variety of materials, from the usual newspaper, cardboard, and mixed containers to new streams such as wood waste, scrap metal, aseptic packaging (milk and juice boxes), and even textiles. State municipalities are in the process of adding many of these new recyclable streams into their curbside collection programs, all of which feed the facility.

  19. Terrestrial bird population trends on Aguiguan (Goat Island), Mariana Islands

    USGS Publications Warehouse

    Amidon, Fred; Camp, Richard J.; Marshall, Ann P.; Pratt, Thane K.; Williams, Laura; Radley, Paul; Cruz, Justine B.

    2014-01-01

    The island of Aguiguan is part of the Mariana archipelago and currently supports populations of four endemic species, including one endemic genus, Cleptornis. Bird population trends since 1982 were recently assessed on the neighbouring islands of Saipan, Tinian, and Rota indicating declines in some native species. Point-transect surveys were conducted in 2008 by the U.S. Fish and Wildlife Service to assess population densities and trends on Aguiguan. Densities for six of the nine native birds—White-throated Ground-dove Gallicolumba xanthonura, Collared Kingfisher Todiramphus chloris, Rufous Fantail Rhipidura rufifrons, Golden White-eye Cleptornis marchei, Bridled White-eye Zosterops conspicillatus and Micronesian Starling Aplonis opaca—and the non-native bird—Island Collared-dove Streptopelia bitorquata—were significantly greater in 2008 than in 1982. No differences in densities were detected among the surveys for Mariana Fruit-dove Ptilinopus roseicapilla, and Micronesian MyzomelaMyzomela rubratra. Three federally and locally listed endangered birds—Nightingale Reed-warbler Acrocephalus luscinius, Mariana Swiftlet Collocalia bartschi, and Micronesian Megapode Megapodius laperous)—were either not detected during the point-transect counts, the surveys were not appropriate for the species, or the numbers of birds detected were too small to estimate densities. The factors behind the increasing trends for some species are unknown but may be related to increased forest cover on the island since 1982. With declining trends for some native species on neighbouring islands, the increasing and stable trends on Aguiguan is good news for forest bird populations in the region, as Aguiguan populations can help support conservation efforts on other islands in the archipelago.

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

    PubMed

    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

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

    PubMed

    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

  2. Bloodborne Pathogens Exposure Control Plan.

    ERIC Educational Resources Information Center

    National Child Care Association, Atlanta, GA.

    This sample exposure control plan is a guide to assist child care providers in complying with the blood-borne pathogens standard issued by the Occupational Safety and Health Administration (OSHA). The standard requires employers to establish a written exposure control plan by May 5, 1992 (for exposure to microorganisms in human blood that cause…

  3. Asian citrus psyllid viral pathogen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A newly discovered viral pathogen of Asian citrus psyllid, AsCP, Diaphorina citri, Kuwayama (Psyllidae: Hemiptera) was classified as a Reoviridae. This virus may serve as a biological control agent for AsCP. The AsCP is an efficient vector of the plant-infecting bacterium (Candidatus Liberibacter as...

  4. Biosignatures of Pathogen and Host

    SciTech Connect

    Fitch, J P; Chromy, B A; Forde, C E; Garcia, E; Gardner, S N; Gu, P P; Kuczmarksi, T A; Melius, C F; McCutchen-Maloney, S L; Milanovich, F P; Motin, V L; Ott, L L; Quong, A A; Quong, J N; Rocco, J M; Slezak, T R; Sokhansanj, B A; Vitalis, E A; Zemla, A T; McCready, P M

    2002-08-27

    In information theory, a signature is characterized by the information content as well as noise statistics of the communication channel. Biosignatures have analogous properties. A biosignature can be associated with a particular attribute of a pathogen or a host. However, the signature may be lost in backgrounds of similar or even identical signals from other sources. In this paper, we highlight statistical and signal processing challenges associated with identifying good biosignatures for pathogens in host and other environments. In some cases it may be possible to identify useful signatures of pathogens through indirect but amplified signals from the host. Discovery of these signatures requires new approaches to modeling and data interpretation. For environmental biosignal collections, it is possible to use signal processing techniques from other applications (e.g., synthetic aperture radar) to track the natural progression of microbes over large areas. We also present a computer-assisted approach to identify unique nucleic-acid based microbial signatures. Finally, an understanding of host-pathogen interactions will result in better detectors as well as opportunities in vaccines and therapeutics.

  5. Microbial Forensics and Plant Pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    New awareness of the vulnerability of a nation's agricultural infrastructure to the intentional introduction of pathogens or pests has led to the enhancement of programs for prevention and preparedness. A necessary component of a balanced bio-security plan is the capability to determine whether an ...

  6. Ustilago maydis as a Pathogen.

    PubMed

    Brefort, Thomas; Doehlemann, Gunther; Mendoza-Mendoza, Artemio; Reissmann, Stefanie; Djamei, Armin; Kahmann, Regine

    2009-01-01

    The Ustilago maydis-maize pathosystem has emerged as the current model for plant pathogenic basidiomycetes and as one of the few models for a true biotrophic interaction that persists throughout fungal development inside the host plant. This is based on the highly advanced genetic system for both the pathogen and its host, the ability to propagate U. maydis in axenic culture, and its unique capacity to induce prominent disease symptoms (tumors) on all aerial parts of maize within less than a week. The corn smut pathogen, though economically not threatening, will continue to serve as a model for related obligate biotrophic fungi such as the rusts, but also for closely related smut species that induce symptoms only in the flower organs of their hosts. In this review we describe the most prominent features of the U. maydis-maize pathosystem as well as genes and pathways most relevant to disease. We highlight recent developments that place this system at the forefront of understanding the function of secreted effectors in eukaryotic pathogens and describe the expected spin-offs for closely related species exploiting comparative genomics approaches.

  7. USEPA PERSPECTIVE ON CONTROLLING PATHOGENS

    EPA Science Inventory

    EPA minimizes the risk of infectious diseases from the beneficial use of sludge by requiring its treatment to reduce pathogen levels below the detection limit. How new treatment processes can be shown equivalent to ones specified in 40CFR503 will be discussed together with ways t...

  8. The Evolution of Foodborne Pathogens

    NASA Astrophysics Data System (ADS)

    Abu-Ali, Galeb S.; Manning, Shannon D.

    Despite continuous advances in food safety and disease surveillance, control, and prevention, foodborne bacterial infections remain a major public health concern. Because foodborne pathogens are commonly exposed to multiple environmental stressors, such as low pH and antibiotics, most have evolved specific mechanisms to facilitate survival in adverse environments.

  9. MANAGING URBAN WATERSHED PATHOGEN CONTAMINATION

    EPA Science Inventory

    This presentation is a summary of the EPA National Risk Management Research Laboratory (NRMRL) publication entitled Managing Urban Watershed Pathogen Contamination, EPA/600/R-03/111 (September 2003). It is available on the internet at http://www.epa.gov/ednnrmrl/repository/water...

  10. Proteomics of foodborne bacterial pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter focuses on recent research on foodborne bacterial pathogens that use mass spectrometry-based proteomic techniques as well as protein microarrays. Mass spectrometry ionization techniques (e.g. electrospray ionization and matrix-assisted laser desorption/ionization), analyzers (e.g. ion ...

  11. EXTRAINTESTINAL PATHOGENIC ESCHERICHIA COLI (EXPEC)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extraintestinal pathogenic Escherichia coli (ExPEC) possess virulence traits that allow them to invade, colonize, and induce disease in bodily sites outside of the gastrointestinal tract. Human diseases caused by ExPEC include urinary tract infections, neonatal meningitis, sepsis, pneumonia, surgic...

  12. Photosymbiotic ascidians from Pari Island (Thousand Islands, Indonesia).

    PubMed

    Hirose, Euichi; Iskandar, Budhi Hascaryo; Wardiatno, Yusli

    2014-01-01

    Photosymbiotic ascidian fauna were surveyed in the subtidal zone off Pari Island in the Thousand Islands (Java Sea, Indonesia). Nine species were recorded: Didemnum molle, Trididemnum miniatum, Lissoclinum patella, L. punctatum, L. timorense, Diplosoma gumavirens, D. simile, D. simileguwa, and D. virens. All of these species have been previously recorded in the Ryukyu Archipelago, Japan. Diplosoma gumavirens and D. simileguwa were originally described from the Ryukyu Archipelago in 2009 and 2005, respectively, and all of the observed species are potentially widely distributed in Indo-West Pacific coral reefs. PMID:25061385

  13. Wall teichoic acid structure governs horizontal gene transfer between major bacterial pathogens.

    PubMed

    Winstel, Volker; Liang, Chunguang; Sanchez-Carballo, Patricia; Steglich, Matthias; Munar, Marta; Bröker, Barbara M; Penadés, Jose R; Nübel, Ulrich; Holst, Otto; Dandekar, Thomas; Peschel, Andreas; Xia, Guoqing

    2013-01-01

    Mobile genetic elements (MGEs) encoding virulence and resistance genes are widespread in bacterial pathogens, but it has remained unclear how they occasionally jump to new host species. Staphylococcus aureus clones exchange MGEs such as S. aureus pathogenicity islands (SaPIs) with high frequency via helper phages. Here we report that the S. aureus ST395 lineage is refractory to horizontal gene transfer (HGT) with typical S. aureus but exchanges SaPIs with other species and genera including Staphylococcus epidermidis and Listeria monocytogenes. ST395 produces an unusual wall teichoic acid (WTA) resembling that of its HGT partner species. Notably, distantly related bacterial species and genera undergo efficient HGT with typical S. aureus upon ectopic expression of S. aureus WTA. Combined with genomic analyses, these results indicate that a 'glycocode' of WTA structures and WTA-binding helper phages permits HGT even across long phylogenetic distances thereby shaping the evolution of Gram-positive pathogens.

  14. Recent evolution of bacterial pathogens: the gall-forming Pantoea agglomerans case.

    PubMed

    Barash, Isaac; Manulis-Sasson, Shulamit

    2009-01-01

    Pantoea agglomerans, a widespread epiphyte and commensal bacterium, has evolved into an Hrp-dependent and host-specific tumorigenic pathogen by acquiring a plasmid containing a pathogenicity island (PAI). The PAI was evolved on an iteron plasmid of the IncN family, which is distributed among genetically diverse populations of P. agglomerans. The structure of the PAI supports the premise of a recently evolved pathogen. This review offers insight into a unique model for emergence of new bacterial pathogens. It illustrates how horizontal gene transfer was the major driving force in the creation of the PAI, although a pathoadaptive mechanism might also be involved. It describes the crucial function of plant-produced indole-3-acetic acid (IAA) and cytokinines (CK) in gall initiation as opposed to the significant but secondary role of pathogen-secreted phytohormones. It also unveils the role of type III effectors in determination of host specificity and evolution of the pathogen into pathovars. Finally, it describes how interactions between the quorum sensing system, hrp regulatory genes, and bacterially secreted IAA or CKs affect gall formation and epiphytic fitness.

  15. Late Quaternary climate change shapes island biodiversity.

    PubMed

    Weigelt, Patrick; Steinbauer, Manuel Jonas; Cabral, Juliano Sarmento; Kreft, Holger

    2016-04-01

    Island biogeographical models consider islands either as geologically static with biodiversity resulting from ecologically neutral immigration-extinction dynamics, or as geologically dynamic with biodiversity resulting from immigration-speciation-extinction dynamics influenced by changes in island characteristics over millions of years. Present climate and spatial arrangement of islands, however, are rather exceptional compared to most of the Late Quaternary, which is characterized by recurrent cooler and drier glacial periods. These climatic oscillations over short geological timescales strongly affected sea levels and caused massive changes in island area, isolation and connectivity, orders of magnitude faster than the geological processes of island formation, subsidence and erosion considered in island theory. Consequences of these oscillations for present biodiversity remain unassessed. Here we analyse the effects of present and Last Glacial Maximum (LGM) island area, isolation, elevation and climate on key components of angiosperm diversity on islands worldwide. We find that post-LGM changes in island characteristics, especially in area, have left a strong imprint on present diversity of endemic species. Specifically, the number and proportion of endemic species today is significantly higher on islands that were larger during the LGM. Native species richness, in turn, is mostly determined by present island characteristics. We conclude that an appreciation of Late Quaternary environmental change is essential to understand patterns of island endemism and its underlying evolutionary dynamics. PMID:27027291

  16. Thermal island destabilization and the Greenwald limit

    SciTech Connect

    White, R. B.; Gates, D. A.; Brennan, D. P.

    2015-02-15

    Magnetic reconnection is ubiquitous in the magnetosphere, the solar corona, and in toroidal fusion research discharges. In a fusion device, a magnetic island saturates at a width which produces a minimum in the magnetic energy of the configuration. At saturation, the modified current density profile, a function of the flux in the island, is essentially flat, the growth rate proportional to the difference in the current at the O-point and the X-point. Further modification of the current density profile in the island interior causes a change in the island stability and additional growth or contraction of the saturated island. Because field lines in an island are isolated from the outside plasma, an island can heat or cool preferentially depending on the balance of Ohmic heating and radiation loss in the interior, changing the resistivity and hence the current in the island. A simple model of island destabilization due to radiation cooling of the island is constructed, and the effect of modification of the current within an island is calculated. An additional destabilization effect is described, and it is shown that a small imbalance of heating can lead to exponential growth of the island. A destabilized magnetic island near the plasma edge can lead to plasma loss, and because the radiation is proportional to plasma density and charge, this effect can cause an impurity dependent density limit.

  17. Late Quaternary climate change shapes island biodiversity.

    PubMed

    Weigelt, Patrick; Steinbauer, Manuel Jonas; Cabral, Juliano Sarmento; Kreft, Holger

    2016-04-01

    Island biogeographical models consider islands either as geologically static with biodiversity resulting from ecologically neutral immigration-extinction dynamics, or as geologically dynamic with biodiversity resulting from immigration-speciation-extinction dynamics influenced by changes in island characteristics over millions of years. Present climate and spatial arrangement of islands, however, are rather exceptional compared to most of the Late Quaternary, which is characterized by recurrent cooler and drier glacial periods. These climatic oscillations over short geological timescales strongly affected sea levels and caused massive changes in island area, isolation and connectivity, orders of magnitude faster than the geological processes of island formation, subsidence and erosion considered in island theory. Consequences of these oscillations for present biodiversity remain unassessed. Here we analyse the effects of present and Last Glacial Maximum (LGM) island area, isolation, elevation and climate on key components of angiosperm diversity on islands worldwide. We find that post-LGM changes in island characteristics, especially in area, have left a strong imprint on present diversity of endemic species. Specifically, the number and proportion of endemic species today is significantly higher on islands that were larger during the LGM. Native species richness, in turn, is mostly determined by present island characteristics. We conclude that an appreciation of Late Quaternary environmental change is essential to understand patterns of island endemism and its underlying evolutionary dynamics.

  18. Thermal island destabilization and the Greenwald limit

    DOE PAGES

    White, R. B.; Gates, D. A.; Brennan, D. P.

    2015-02-24

    Magnetic reconnection is ubiquitous in the magnetosphere, the solar corona, and in toroidal fusion research discharges. A magnetic island saturates at a width which produces a minimum in the magnetic energy of the configuration is evident in a fusion device. At saturation, the modified current density profile, a function of the flux in the island, is essentially flat, the growth rate proportional to the difference in the current at the O-point and the X-point. Furthermore, modification of the current density profile in the island interior causes a change in the island stability and additional growth or contraction of the saturatedmore » island. Because field lines in an island are isolated from the outside plasma, an island can heat or cool preferentially depending on the balance of Ohmic heating and radiation loss in the interior, changing the resistivity and hence the current in the island. A simple model of island destabilization due to radiation cooling of the island is constructed, and the effect of modification of the current within an island is calculated. In addition destabilization effect is described, and it is shown that a small imbalance of heating can lead to exponential growth of the island. A destabilized magnetic island near the plasma edge can lead to plasma loss, and because the radiation is proportional to plasma density and charge, this effect can cause an impurity dependent density limit.« less

  19. Thermal island destabilization and the Greenwald limit

    SciTech Connect

    White, R. B.; Gates, D. A.; Brennan, D. P.

    2015-02-24

    Magnetic reconnection is ubiquitous in the magnetosphere, the solar corona, and in toroidal fusion research discharges. A magnetic island saturates at a width which produces a minimum in the magnetic energy of the configuration is evident in a fusion device. At saturation, the modified current density profile, a function of the flux in the island, is essentially flat, the growth rate proportional to the difference in the current at the O-point and the X-point. Furthermore, modification of the current density profile in the island interior causes a change in the island stability and additional growth or contraction of the saturated island. Because field lines in an island are isolated from the outside plasma, an island can heat or cool preferentially depending on the balance of Ohmic heating and radiation loss in the interior, changing the resistivity and hence the current in the island. A simple model of island destabilization due to radiation cooling of the island is constructed, and the effect of modification of the current within an island is calculated. In addition destabilization effect is described, and it is shown that a small imbalance of heating can lead to exponential growth of the island. A destabilized magnetic island near the plasma edge can lead to plasma loss, and because the radiation is proportional to plasma density and charge, this effect can cause an impurity dependent density limit.

  20. Is heterostyly rare on oceanic islands?

    PubMed Central

    Watanabe, Kenta; Sugawara, Takashi

    2015-01-01

    Heterostyly has been considered rare or absent on oceanic islands. However, there has been no comprehensive review on this issue. Is heterostyly truly rare on oceanic islands? What makes heterostyly rare on such islands? To answer these questions, we review the reproductive studies on heterostyly on oceanic islands, with special emphasis on the heterostylous genus Psychotria in the Pacific Ocean as a model system. Overall, not many reproductive studies have been performed on heterostylous species on oceanic islands. In Hawaiian Psychotria, all 11 species are thought to have evolved dioecy from distyly. In the West Pacific, three species on the oceanic Bonin and Lanyu Islands are distylous (Psychotria homalosperma, P. boninensis and P. cephalophora), whereas three species on the continental Ryukyu Islands show various breeding systems, such as distyly (P. serpens), dioecy (P. rubra) and monoecy (P. manillensis). On some other Pacific oceanic islands, possibilities of monomorphy have been reported. For many Psychotria species, breeding systems are unknown, although recent studies indicate that heterostylous species may occur on some oceanic islands. A shift from heterostyly to other sexual systems may occur on some oceanic islands. This tendency may also contribute to the rarity of heterostyly, in addition to the difficulty in colonization/autochthonous evolution of heterostylous species on oceanic islands. Further investigation of reproductive systems of Psychotria on oceanic islands using robust phylogenetic frameworks would provide new insights into plant reproduction on oceanic islands. PMID:26199401