Sample records for obligate intracellular pathogen

  1. Advances in Genetic Manipulation of Obligate Intracellular Bacterial Pathogens

    PubMed Central

    Beare, Paul A.; Sandoz, Kelsi M.; Omsland, Anders; Rockey, Daniel D.; Heinzen, Robert A.

    2011-01-01

    Infections by obligate intracellular bacterial pathogens result in significant morbidity and mortality worldwide. These bacteria include Chlamydia spp., which causes millions of cases of sexually transmitted disease and blinding trachoma annually, and members of the ?-proteobacterial genera Anaplasma, Ehrlichia, Orientia, and Rickettsia, agents of serious human illnesses including epidemic typhus. Coxiella burnetii, the agent of human Q fever, has also been considered a prototypical obligate intracellular bacterium, but recent host cell-free (axenic) growth has rescued it from obligatism. The historic genetic intractability of obligate intracellular bacteria has severely limited molecular dissection of their unique lifestyles and virulence factors involved in pathogenesis. Host cell restricted growth is a significant barrier to genetic transformation that can make simple procedures for free-living bacteria, such as cloning, exceedingly difficult. Low transformation efficiency requiring long-term culture in host cells to expand small transformant populations is another obstacle. Despite numerous technical limitations, the last decade has witnessed significant gains in genetic manipulation of obligate intracellular bacteria including allelic exchange. Continued development of genetic tools should soon enable routine mutation and complementation strategies for virulence factor discovery and stimulate renewed interest in these refractory pathogens. In this review, we discuss the technical challenges associated with genetic transformation of obligate intracellular bacteria and highlight advances made with individual genera. PMID:21833334

  2. An Optimal Method of Iron Starvation of the Obligate Intracellular Pathogen, Chlamydia Trachomatis

    PubMed Central

    Thompson, Christopher C.; Carabeo, Rey A.

    2011-01-01

    Iron is an essential cofactor in a number of critical biochemical reactions, and as such, its acquisition, storage, and metabolism is highly regulated in most organisms. The obligate intracellular bacterium, Chlamydia trachomatis experiences a developmental arrest when iron within the host is depleted. The nature of the iron starvation response in Chlamydia is relatively uncharacterized because of the likely inefficient method of iron depletion, which currently relies on the compound deferoxamine mesylate (DFO). Inefficient induction of the iron starvation response precludes the identification of iron-regulated genes. This report evaluated DFO with another iron chelator, 2,2?-bipyridyl (Bpdl) and presented a systematic comparison of the two across a range of criteria. We demonstrate that the membrane permeable Bpdl was superior to DFO in the inhibition of chlamydia development, the induction of aberrant morphology, and the induction of an iron starvation transcriptional response in both host and bacteria. Furthermore, iron starvation using Bpdl identified the periplasmic iron-binding protein-encoding ytgA gene as iron-responsive. Overall, the data present a compelling argument for the use of Bpdl, rather than DFO, in future iron starvation studies of chlamydia and other intracellular bacteria. PMID:21687412

  3. Laser microdissection coupled with RNA-seq analysis of porcine enterocytes infected with an obligate intracellular pathogen (Lawsonia intracellularis)

    PubMed Central

    2013-01-01

    Background Lawsonia intracellularis is an obligate intracellular bacterium and the etiologic agent of proliferative enteropathy. The disease is endemic in pigs, emerging in horses and has been described in various other species including nonhuman primates. Cell proliferation is associated with bacterial replication in enterocyte cytoplasm, but the molecular basis of the host-pathogen interaction is unknown. We used laser capture microdissection coupled with RNA-seq technology to characterize the transcriptional responses of infected enterocytes and the host-pathogen interaction. Results Proliferative enterocytes was associated with activation of transcription, protein biosynthesis and genes acting on the G1 phase of the host cell cycle (Rho family). The lack of differentiation in infected enterocytes was demonstrated by the repression of membrane transporters related to nutrient acquisition. The activation of the copper uptake transporter by infected enterocytes was associated with high expression of the Zn/Cu superoxide dismutase by L. intracellularis. This suggests that the intracellular bacteria incorporate intracytoplasmic copper and express a sophisticated mechanism to cope with oxidative stress. Conclusions The feasibility of coupling microdissection and RNA-seq was demonstrated by characterizing the host-bacterial interactions from a specific cell type in a heterogeneous tissue. High expression of L. intracellularis genes encoding hypothetical proteins and activation of host Rho genes infers the role of unrecognized bacterial cyclomodulins in the pathogenesis of proliferative enteropathy. PMID:23800029

  4. Virulence determinants in the obligate intracellular pathogen Chlamydia trachomatis revealed by forward genetic approaches

    PubMed Central

    Nguyen, Bidong D.; Valdivia, Raphael H.

    2012-01-01

    Chlamydia trachomatis, a pathogen responsible for diseases of significant clinical and public health importance, remains poorly characterized because of its intractability to routine molecular genetic manipulation. We have developed a combinatorial approach to rapidly generate a comprehensive library of genetically defined mutants. Chemical mutagenesis, coupled with whole-genome sequencing (WGS) and a system for DNA exchange within infected cells, was used to generate Chlamydia mutants with distinct phenotypes, map the underlying genetic lesions, and generate isogenic strains. As a result, we identified mutants with altered glycogen metabolism, including an attenuated strain defective for type II secretion. The coupling of chemically induced gene variation and WGS to establish genotype–phenotype associations should be broadly applicable to the large list of medically and environmentally important microorganisms currently intractable to genetic analysis. PMID:22232666

  5. Transient Transfection and Expression in the Obligate Intracellular Parasite Toxoplasma gondii

    Microsoft Academic Search

    Dominique Soldati; John C. Boothroyd

    1993-01-01

    Toxoplasma gondii is a protozoan pathogen that produces severe disease in humans and animals. This obligate intracellular parasite provides an excellent model for the study of how such pathogens are able to invade, survive, and replicate intracellularly. DNA encoding chloramphenicol acetyltransferase was introduced into T. gondii and transiently expressed with the use of three vectors based on different Toxoplasma genes.

  6. Exit strategies of intracellular pathogens

    Microsoft Academic Search

    Kevin Hybiske; Richard S. Stephens

    2008-01-01

    The exit of intracellular pathogens from host cells is an important step in the infectious cycle, but is poorly understood. It has recently emerged that microbial exit is a process that can be directed by organisms from within the cell, and is not simply a consequence of the physical or metabolic burden that is imposed on the host cell. This

  7. An obligately endosymbiotic mycorrhizal fungus itself harbors obligately intracellular bacteria.

    PubMed Central

    Bianciotto, V; Bandi, C; Minerdi, D; Sironi, M; Tichy, H V; Bonfante, P

    1996-01-01

    Arbuscular-mycorrhizal fungi are obligate endosymbionts that colonize the roots of almost 80% of land plants. This paper describes the employment of a combined morphological and molecular approach to demonstrate that the cytoplasm of the arbuscular-mycorrhizal fungus Gigaspora margarita harbors a further bacterial endosymbiont. Intracytoplasmic bacterium-like organisms (BLOs) were detected ultrastructurally in its spores and germinating and symbiotic mycelia. Morphological observations with a fluorescent stain revealed about 250,000 live bacteria inside each spore. The sequence for the small-subunit rRNA gene obtained for the BLOs from the spores was compared with those for representatives of the eubacterial lineages. Molecular phylogenetic analysis unambiguously showed that the endosymbiont of G. margarita was an rRNA group II pseudomanad (genus Burkholderia). PCR assays with specifically designed oligonucleotides were used to check that the sequence came from the BLOs. Successful amplification was obtained when templates from both the spores and the symbiotic mycelia were used. A band of the expected length was also obtained from spores of a Scutellospora sp. No bands were given by the negative controls. These findings indicate that mycorrhizal systems can include plant, fungal, and bacterial cells. PMID:8702293

  8. Lateral phage transfer in obligate intracellular bacteria (Wolbachia): Verification from natural populations

    E-print Network

    Bordenstein, Seth

    and produce active phage particles, and rampantly transfers between Wolbachia infections (Masui et al. 2000Lateral phage transfer in obligate intracellular bacteria (Wolbachia): Verification from natural, obligate intracellular bacteria, recombination, coinfection Running head: Lateral phage transfer Title

  9. Rickettsia Phylogenomics: Unwinding the Intricacies of Obligate Intracellular Life

    PubMed Central

    Gillespie, Joseph J.; Williams, Kelly; Shukla, Maulik; Snyder, Eric E.; Nordberg, Eric K.; Ceraul, Shane M.; Dharmanolla, Chitti; Rainey, Daphne; Soneja, Jeetendra; Shallom, Joshua M.; Vishnubhat, Nataraj Dongre; Wattam, Rebecca; Purkayastha, Anjan; Czar, Michael; Crasta, Oswald; Setubal, Joao C.; Azad, Abdu F.; Sobral, Bruno S.

    2008-01-01

    Background Completed genome sequences are rapidly increasing for Rickettsia, obligate intracellular ?-proteobacteria responsible for various human diseases, including epidemic typhus and Rocky Mountain spotted fever. In light of phylogeny, the establishment of orthologous groups (OGs) of open reading frames (ORFs) will distinguish the core rickettsial genes and other group specific genes (class 1 OGs or C1OGs) from those distributed indiscriminately throughout the rickettsial tree (class 2 OG or C2OGs). Methodology/Principal Findings We present 1823 representative (no gene duplications) and 259 non-representative (at least one gene duplication) rickettsial OGs. While the highly reductive (?1.2 MB) Rickettsia genomes range in predicted ORFs from 872 to 1512, a core of 752 OGs was identified, depicting the essential Rickettsia genes. Unsurprisingly, this core lacks many metabolic genes, reflecting the dependence on host resources for growth and survival. Additionally, we bolster our recent reclassification of Rickettsia by identifying OGs that define the AG (ancestral group), TG (typhus group), TRG (transitional group), and SFG (spotted fever group) rickettsiae. OGs for insect-associated species, tick-associated species and species that harbor plasmids were also predicted. Through superimposition of all OGs over robust phylogeny estimation, we discern between C1OGs and C2OGs, the latter depicting genes either decaying from the conserved C1OGs or acquired laterally. Finally, scrutiny of non-representative OGs revealed high levels of split genes versus gene duplications, with both phenomena confounding gene orthology assignment. Interestingly, non-representative OGs, as well as OGs comprised of several gene families typically involved in microbial pathogenicity and/or the acquisition of virulence factors, fall predominantly within C2OG distributions. Conclusion/Significance Collectively, we determined the relative conservation and distribution of 14354 predicted ORFs from 10 rickettsial genomes across robust phylogeny estimation. The data, available at PATRIC (PathoSystems Resource Integration Center), provide novel information for unwinding the intricacies associated with Rickettsia pathogenesis, expanding the range of potential diagnostic, vaccine and therapeutic targets. PMID:19194535

  10. Metabolic Interdependence of Obligate Intracellular Bacteria and Their Insect Hosts†

    PubMed Central

    Zientz, Evelyn; Dandekar, Thomas; Gross, Roy

    2004-01-01

    Mutualistic associations of obligate intracellular bacteria and insects have attracted much interest in the past few years due to the evolutionary consequences for their genome structure. However, much less attention has been paid to the metabolic ramifications for these endosymbiotic microorganisms, which have to compete with but also to adapt to another metabolism—that of the host cell. This review attempts to provide insights into the complex physiological interactions and the evolution of metabolic pathways of several mutualistic bacteria of aphids, ants, and tsetse flies and their insect hosts. PMID:15590782

  11. Molecular pathogenesis of the obligate intracellular bacterium Coxiella burnetii

    PubMed Central

    van Schaik, Erin J.; Chen, Chen; Mertens, Katja; Weber, Mary M.; Samuel, James E.

    2014-01-01

    The agent of Q fever, Coxiella burnetii, is an obligate intracellular bacterium that causes acute and chronic infections. The study of C. burnetii pathogenesis has benefited from two recent fundamental advances: improved genetic tools and the ability to grow the bacterium in extracellular media. In this Review, we describe how these recent advances have improved our understanding of C. burnetii invasion and host cell modulation, including the formation of replication-permissive Coxiella-containing vacuoles. Furthermore, we describe the Dot/Icm (defect in organelle trafficking/intracellular multiplication) system, which is used by C. burnetii to secrete a range of effector proteins into the host cell, and we discuss the role of these effectors in remodelling the host cell. PMID:23797173

  12. Genetic regulation of resistance to intracellular pathogens

    Microsoft Academic Search

    Emil Skamene; Philippe Gros; Adrien Forget; Patricia A. L. Kongshavn; Carole St Charles; Benjamin A. Taylor

    1982-01-01

    Natural resistance of mice to infections with Salmonella typhimurium and Leishmania donovani is regulated by chromosome 1 gene(s) designated Ity and Lsh, respectively1,2. Given the fact that these two microorganisms are taxonomically and antigenically distinct, and yet the host response to them is regulated by the same locus or complex3,4, one might expect that the resistance to other intracellular pathogens

  13. Strategies of Intracellular Pathogens for Obtaining Iron from the Environment

    PubMed Central

    Leon-Sicairos, Nidia; Reyes-Cortes, Ruth; Guadrón-Llanos, Alma M.; Madueña-Molina, Jesús; Leon-Sicairos, Claudia; Canizalez-Román, Adrian

    2015-01-01

    Most microorganisms are destroyed by the host tissues through processes that usually involve phagocytosis and lysosomal disruption. However, some organisms, called intracellular pathogens, are capable of avoiding destruction by growing inside macrophages or other cells. During infection with intracellular pathogenic microorganisms, the element iron is required by both the host cell and the pathogen that inhabits the host cell. This minireview focuses on how intracellular pathogens use multiple strategies to obtain nutritional iron from the intracellular environment in order to use this element for replication. Additionally, the implications of these mechanisms for iron acquisition in the pathogen-host relationship are discussed. PMID:26120582

  14. Nanomedicine as an emerging approach against intracellular pathogens

    PubMed Central

    Armstead, Andrea L; Li, Bingyun

    2011-01-01

    Diseases such as tuberculosis, hepatitis, and HIV/AIDS are caused by intracellular pathogens and are a major burden to the global medical community. Conventional treatments for these diseases typically consist of long-term therapy with a combination of drugs, which may lead to side effects and contribute to low patient compliance. The pathogens reside within intracellular compartments of the cell, which provide additional barriers to effective treatment. Therefore, there is a need for improved and more effective therapies for such intracellular diseases. This review will summarize, for the first time, the intracellular compartments in which pathogens can reside and discuss how nanomedicine has the potential to improve intracellular disease therapy by offering properties such as targeting, sustained drug release, and drug delivery to the pathogen’s intracellular location. The characteristics of nanomedicine may prove advantageous in developing improved or alternative therapies for intracellular diseases. PMID:22228996

  15. The role of autophagy in intracellular pathogen nutrient acquisition

    PubMed Central

    Steele, Shaun; Brunton, Jason; Kawula, Thomas

    2015-01-01

    Following entry into host cells intracellular pathogens must simultaneously evade innate host defense mechanisms and acquire energy and anabolic substrates from the nutrient-limited intracellular environment. Most of the potential intracellular nutrient sources are stored within complex macromolecules that are not immediately accessible by intracellular pathogens. To obtain nutrients for proliferation, intracellular pathogens must compete with the host cell for newly-imported simple nutrients or degrade host nutrient storage structures into their constituent components (fatty acids, carbohydrates, and amino acids). It is becoming increasingly evident that intracellular pathogens have evolved a wide variety of strategies to accomplish this task. One recurrent microbial strategy is to exploit host degradative processes that break down host macromolecules into simple nutrients that the microbe can use. Herein we focus on how a subset of bacterial, viral, and eukaryotic pathogens leverage the host process of autophagy to acquire nutrients that support their growth within infected cells.

  16. INTRODUCTION: Intracellular pathogens, which include viruses and some bacteria,

    E-print Network

    Napp, Nils

    RESEARCH INTRODUCTION: Intracellular pathogens, which include viruses and some bacteria, typically in the extracellular environment, pathogens can be intercepted by humoral immunity or by professional immune cells. How mechanisms to detect and disable pathogens. RATIONALE: We hypothesized that one method of pathogen detection

  17. Evolutionary Genomics of a Temperate Bacteriophage in an Obligate Intracellular Bacteria (Wolbachia)

    E-print Network

    Bordenstein, Seth

    Evolutionary Genomics of a Temperate Bacteriophage in an Obligate Intracellular Bacteria (Wolbachia, Vanderbilt University, Nashville, Tennessee, United States of America Abstract Genome evolution of bacteria is usually influenced by ecology, such that bacteria with a free-living stage have large genomes and high

  18. Multi locus sequence typing of Chlamydiales: clonal groupings within the obligate intracellular bacteria Chlamydia trachomatis

    Microsoft Academic Search

    Yvonne Pannekoek; Giovanna Morelli; Barica Kusecek; Servaas A Morré; Jacobus M Ossewaarde; Ankie A Langerak; Arie van der Ende

    2008-01-01

    BACKGROUND: The obligate intracellular growing bacterium Chlamydia trachomatis causes diseases like trachoma, urogenital infection and lymphogranuloma venereum with severe morbidity. Several serovars and genotypes have been identified, but these could not be linked to clinical disease or outcome. The related Chlamydophila pneumoniae, of which no subtypes are recognized, causes respiratory infections worldwide. We developed a multi locus sequence typing (MLST)

  19. Transposon Mutagenesis of the Obligate Intracellular Pathogen Rickettsia prowazekii

    Microsoft Academic Search

    Aiping Qin; Aimee M. Tucker; Andria Hines; David O. Wood

    2004-01-01

    Genetic analysis of Rickettsia prowazekii has been hindered by the lack of selectable markers and efficient mechanisms for generating rickettsial gene knockouts. We have addressed these problems by adapting a gene that codes for rifampin resistance for expression in R. prowazekii and by incorporating this selection into a transposon mutagenesis system suitable for generating rickettsial gene knockouts. The arr-2 gene

  20. Evolutionary Genomics of a Temperate Bacteriophage in an Obligate Intracellular Bacteria (Wolbachia)

    PubMed Central

    Kent, Bethany N.; Funkhouser, Lisa J.; Setia, Shefali; Bordenstein, Seth R.

    2011-01-01

    Genome evolution of bacteria is usually influenced by ecology, such that bacteria with a free-living stage have large genomes and high rates of horizontal gene transfer, while obligate intracellular bacteria have small genomes with typically low amounts of gene exchange. However, recent studies indicate that obligate intracellular species that host-switch frequently harbor agents of horizontal transfer such as mobile elements. For example, the temperate double-stranded DNA bacteriophage WO in Wolbachia persistently transfers between bacterial coinfections in the same host. Here we show that despite the phage's rampant mobility between coinfections, the prophage's genome displays features of constraint related to its intracellular niche. First, there is always at least one intact prophage WO and usually several degenerate, independently-acquired WO prophages in each Wolbachia genome. Second, while the prophage genomes are modular in composition with genes of similar function grouping together, the modules are generally not interchangeable with other unrelated phages and thus do not evolve by the Modular Theory. Third, there is an unusual core genome that strictly consists of head and baseplate genes; other gene modules are frequently deleted. Fourth, the prophage recombinases are diverse and there is no conserved integration sequence. Finally, the molecular evolutionary forces acting on prophage WO are point mutation, intragenic recombination, deletion, and purifying selection. Taken together, these analyses indicate that while lateral transfer of phage WO is pervasive between Wolbachia with occasional new gene uptake, constraints of the intracellular niche obstruct extensive mixture between WO and the global phage population. Although the Modular Theory has long been considered the paradigm of temperate bacteriophage evolution in free-living bacteria, it appears irrelevant in phages of obligate intracellular bacteria. PMID:21949820

  1. Glutathione activates virulence gene expression of an intracellular pathogen

    PubMed Central

    Reniere, Michelle L.; Whiteley, Aaron T.; Hamilton, Keri L.; John, Sonya M.; Lauer, Peter; Brennan, Richard G.; Portnoy, Daniel A.

    2015-01-01

    Intracellular pathogens are responsible for much of the world-wide morbidity and mortality due to infectious diseases. To colonize their hosts successfully, pathogens must sense their environment and regulate virulence gene expression appropriately. Accordingly, on entry into mammalian cells, the facultative intracellular bacterial pathogen Listeria monocytogenes remodels its transcriptional program by activating the master virulence regulator PrfA. Here we show that bacterial and host-derived glutathione are required to activate PrfA. In this study a genetic selection led to the identification of a bacterial mutant in glutathione synthase that exhibited reduced virulence gene expression and was attenuated 150-fold in mice. Genome sequencing of suppressor mutants that arose spontaneously in vivo revealed a single nucleotide change in prfA that locks the protein in the active conformation (PrfA*) and completely bypassed the requirement for glutathione during infection. Biochemical and genetic studies support a model in which glutathione-dependent PrfA activation is mediated by allosteric binding of glutathione to PrfA. Whereas glutathione and other low-molecular-weight thiols have important roles in redox homeostasis in all forms of life, here we demonstrate that glutathione represents a critical signalling molecule that activates the virulence of an intracellular pathogen. PMID:25567281

  2. Fluorogenic Substrate Detection of Viable Intracellular and Extracellular Pathogenic Protozoa

    NASA Astrophysics Data System (ADS)

    Jackson, Peter R.; Pappas, Michael G.; Hansen, Brian D.

    1985-01-01

    Viable Leishmania promastigotes and amastigotes were detected by epifluorescence microscopy with fluorescein diacetate being used to mark living parasites and the nucleic acid-binding compound ethidium bromide to stain dead cells. This procedure is superior to other assays because it is faster and detects viable intracellular as well as extracellular Leishmania. Furthermore, destruction of intracellular pathogens by macrophages is more accurately determined with fluorescein diacetate than with other stains. The procedure may have applications in programs to develop drugs and vaccines against protozoa responsible for human and animal disease.

  3. Metabolic host responses to infection by intracellular bacterial pathogens

    PubMed Central

    Eisenreich, Wolfgang; Heesemann, Jürgen; Rudel, Thomas; Goebel, Werner

    2013-01-01

    The interaction of bacterial pathogens with mammalian hosts leads to a variety of physiological responses of the interacting partners aimed at an adaptation to the new situation. These responses include multiple metabolic changes in the affected host cells which are most obvious when the pathogen replicates within host cells as in case of intracellular bacterial pathogens. While the pathogen tries to deprive nutrients from the host cell, the host cell in return takes various metabolic countermeasures against the nutrient theft. During this conflicting interaction, the pathogen triggers metabolic host cell responses by means of common cell envelope components and specific virulence-associated factors. These host reactions generally promote replication of the pathogen. There is growing evidence that pathogen-specific factors may interfere in different ways with the complex regulatory network that controls the carbon and nitrogen metabolism of mammalian cells. The host cell defense answers include general metabolic reactions, like the generation of oxygen- and/or nitrogen-reactive species, and more specific measures aimed to prevent access to essential nutrients for the respective pathogen. Accurate results on metabolic host cell responses are often hampered by the use of cancer cell lines that already exhibit various de-regulated reactions in the primary carbon metabolism. Hence, there is an urgent need for cellular models that more closely reflect the in vivo infection conditions. The exact knowledge of the metabolic host cell responses may provide new interesting concepts for antibacterial therapies. PMID:23847769

  4. The Genome of the Obligately Intracellular Bacterium Ehrlichia canis Reveals Themes of Complex Membrane Structure and Immune Evasion Strategies

    SciTech Connect

    Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Doyle, C Kuyler [Center for Biodenfense and Emerging Infectious Diseases; Lykidis, A [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Francino, M P [U.S. Department of Energy, Joint Genome Institute; Chain, Patrick S [ORNL; Shin, M [U.S. Department of Energy, Joint Genome Institute; Malfatti, Stephanie [Lawrence Livermore National Laboratory (LLNL); Larimer, Frank W [ORNL; Copeland, A [U.S. Department of Energy, Joint Genome Institute; Detter, J C [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Richardson, P M [U.S. Department of Energy, Joint Genome Institute; Yu, X J [Center for Biodenfense and Emerging Infectious Diseases; Walker, D H [Center for Biodenfense and Emerging Infectious Diseases; McBride, J W [Center for Biodenfense and Emerging Infectious Diseases; Kyripides, N C [U.S. Department of Energy, Joint Genome Institute

    2006-01-01

    Ehrlichia canis, a small obligately intracellular, tick-transmitted, gram-negative, {alpha}-proteobacterium, is the primary etiologic agent of globally distributed canine monocytic ehrlichiosis. Complete genome sequencing revealed that the E. canis genome consists of a single circular chromosome of 1,315,030 bp predicted to encode 925 proteins, 40 stable RNA species, 17 putative pseudogenes, and a substantial proportion of noncoding sequence (27%). Interesting genome features include a large set of proteins with transmembrane helices and/or signal sequences and a unique serine-threonine bias associated with the potential for O glycosylation that was prominent in proteins associated with pathogen-host interactions. Furthermore, two paralogous protein families associated with immune evasion were identified, one of which contains poly(G-C) tracts, suggesting that they may play a role in phase variation and facilitation of persistent infections. Genes associated with pathogen-host interactions were identified, including a small group encoding proteins (n = 12) with tandem repeats and another group encoding proteins with eukaryote-like ankyrin domains (n = 7).

  5. Disrupting protein expression with Peptide Nucleic Acids reduces infection by obligate intracellular Rickettsia.

    PubMed

    Pelc, Rebecca S; McClure, Jennifer C; Kaur, Simran J; Sears, Khandra T; Rahman, M Sayeedur; Ceraul, Shane M

    2015-01-01

    Peptide Nucleic Acids (PNAs) are single-stranded synthetic nucleic acids with a pseudopeptide backbone in lieu of the phosphodiester linked sugar and phosphate found in traditional oligos. PNA designed complementary to the bacterial Shine-Dalgarno or start codon regions of mRNA disrupts translation resulting in the transient reduction in protein expression. This study examines the use of PNA technology to interrupt protein expression in obligate intracellular Rickettsia sp. Their historically intractable genetic system limits characterization of protein function. We designed PNA targeting mRNA for rOmpB from Rickettsia typhi and rickA from Rickettsia montanensis, ubiquitous factors important for infection. Using an in vitro translation system and competitive binding assays, we determined that our PNAs bind target regions. Electroporation of R. typhi and R. montanensis with PNA specific to rOmpB and rickA, respectively, reduced the bacteria's ability to infect host cells. These studies open the possibility of using PNA to suppress protein synthesis in obligate intracellular bacteria. PMID:25781160

  6. Chromerid genomes reveal the evolutionary path from photosynthetic algae to obligate intracellular parasites.

    PubMed

    Woo, Yong H; Ansari, Hifzur; Otto, Thomas D; Klinger, Christen M; Kolisko, Martin; Michálek, Jan; Saxena, Alka; Shanmugam, Dhanasekaran; Tayyrov, Annageldi; Veluchamy, Alaguraj; Ali, Shahjahan; Bernal, Axel; Del Campo, Javier; Cihlá?, Jaromír; Flegontov, Pavel; Gornik, Sebastian G; Hajdušková, Eva; Horák, Aleš; Janouškovec, Jan; Katris, Nicholas J; Mast, Fred D; Miranda-Saavedra, Diego; Mourier, Tobias; Naeem, Raeece; Nair, Mridul; Panigrahi, Aswini K; Rawlings, Neil D; Padron-Regalado, Eriko; Ramaprasad, Abhinay; Samad, Nadira; Tom?ala, Aleš; Wilkes, Jon; Neafsey, Daniel E; Doerig, Christian; Bowler, Chris; Keeling, Patrick J; Roos, David S; Dacks, Joel B; Templeton, Thomas J; Waller, Ross F; Lukeš, Julius; Oborník, Miroslav; Pain, Arnab

    2015-01-01

    The eukaryotic phylum Apicomplexa encompasses thousands of obligate intracellular parasites of humans and animals with immense socio-economic and health impacts. We sequenced nuclear genomes of Chromera velia and Vitrella brassicaformis, free-living non-parasitic photosynthetic algae closely related to apicomplexans. Proteins from key metabolic pathways and from the endomembrane trafficking systems associated with a free-living lifestyle have been progressively and non-randomly lost during adaptation to parasitism. The free-living ancestor contained a broad repertoire of genes many of which were repurposed for parasitic processes, such as extracellular proteins, components of a motility apparatus, and DNA- and RNA-binding protein families. Based on transcriptome analyses across 36 environmental conditions, Chromera orthologs of apicomplexan invasion-related motility genes were co-regulated with genes encoding the flagellar apparatus, supporting the functional contribution of flagella to the evolution of invasion machinery. This study provides insights into how obligate parasites with diverse life strategies arose from a once free-living phototrophic marine alga. PMID:26175406

  7. Specific isolation of RNA from the grape powdery mildew pathogen Erysiphe necator, an epiphytic, obligate parasite

    Technology Transfer Automated Retrieval System (TEKTRAN)

    RNA expression profiling of obligately parasitic plant microbes is hampered by the requisite interaction of host and parasite. For superficial pathogens like grape powdery mildew as well as for epiphytic saprophytes, growth along the outside surface of the plant allows separation from the host and ...

  8. The Genome Sequence of Rickettsia felis Identifies the First Putative Conjugative Plasmid in an Obligate Intracellular Parasite

    PubMed Central

    2005-01-01

    We sequenced the genome of Rickettsia felis, a flea-associated obligate intracellular ?-proteobacterium causing spotted fever in humans. Besides a circular chromosome of 1,485,148 bp, R. felis exhibits the first putative conjugative plasmid identified among obligate intracellular bacteria. This plasmid is found in a short (39,263 bp) and a long (62,829 bp) form. R. felis contrasts with previously sequenced Rickettsia in terms of many other features, including a number of transposases, several chromosomal toxin–antitoxin genes, many more spoT genes, and a very large number of ankyrin- and tetratricopeptide-motif-containing genes. Host-invasion-related genes for patatin and RickA were found. Several phenotypes predicted from genome analysis were experimentally tested: conjugative pili and mating were observed, as well as ?-lactamase activity, actin-polymerization-driven mobility, and hemolytic properties. Our study demonstrates that complete genome sequencing is the fastest approach to reveal phenotypic characters of recently cultured obligate intracellular bacteria. PMID:15984913

  9. Dual Mechanisms of Metabolite Acquisition by the Obligate Intracytosolic Pathogen Rickettsia prowazekii Reveal Novel Aspects of Triose Phosphate Transport

    PubMed Central

    Frohlich, Kyla M.

    2013-01-01

    Rickettsia prowazekii is an obligate intracytosolic pathogen and the causative agent of epidemic typhus fever in humans. As an evolutionary model of intracellular pathogenesis, rickettsiae are notorious for their use of transport systems that parasitize eukaryotic host cell biochemical pathways. Rickettsial transport systems for substrates found only in eukaryotic cell cytoplasm are uncommon among free-living microorganisms and often possess distinctive mechanisms. We previously reported that R. prowazekii acquires triose phosphates for phospholipid biosynthesis via the coordinated activities of a novel dihydroxyacetone phosphate transport system and an sn-glycerol-3-phosphate dehydrogenase (K. M. Frohlich et al., J. Bacteriol. 192:4281–4288, 2010). In the present study, we have determined that R. prowazekii utilizes a second, independent triose phosphate acquisition pathway whereby sn-glycerol-3-phosphate is directly transported and incorporated into phospholipids. Herein we describe the sn-glycerol-3-phosphate and dihydroxyacetone phosphate transport systems in isolated R. prowazekii with respect to kinetics, energy coupling, transport mechanisms, and substrate specificity. These data suggest the existence of multiple rickettsial triose phosphate transport systems. Furthermore, the R. prowazekii dihydroxyacetone phosphate transport systems displayed unexpected mechanistic properties compared to well-characterized triose phosphate transport systems from plant plastids. Questions regarding possible roles for dual-substrate acquisition pathways as metabolic virulence factors in the context of a pathogen undergoing reductive evolution are discussed. PMID:23772074

  10. Differential accumulation of host mRNAs on polyribosomes during obligate pathogen-plant interactions.

    PubMed

    Moeller, Jackson R; Moscou, Matthew J; Bancroft, Tim; Skadsen, Ronald W; Wise, Roger P; Whitham, Steven A

    2012-08-01

    Plant pathogens elicit dramatic changes in the expression of host genes during both compatible and incompatible interactions. Gene expression profiling studies of plant-pathogen interactions have only considered messenger RNAs (mRNAs) present in total RNA, which contains subpopulations of actively translated mRNAs associated with polyribosomes (polysomes) and non-translated mRNAs that are not associated with polysomes. The goal of this study was to enhance previous gene expression analyses by identifying host mRNAs that become differentially associated with polysomes following pathogen inoculation. Total and polysomal RNA were extracted from barley (Hordeum vulgare) plants at 32 h after inoculation with Blumeria graminis f. sp. hordei, and Arabidopsis thaliana plants at 10 days after inoculation with Turnip mosaic virus. Gene expression profiles were obtained for each pathosystem, which represent diverse plant host-obligate pathogen interactions. Using this approach, host mRNAs were identified that were differentially associated with polysomes in response to pathogen treatment. Approximately 18% and 26% of mRNAs represented by probe sets on the Affymetrix Barley1 and Arabidopsis ATH1 GeneChips, respectively, differentially accumulated in the two populations in one or more combinations of treatment and genotype. Gene ontology analysis of mRNAs sharing the same pattern of accumulation in total and polysomal RNA identified gene sets that contained a significant number of functionally related annotations, suggesting both transcript accumulation and recruitment to polyribosomes are coordinately regulated in these systems. PMID:22660698

  11. Superdiffusion dominates intracellular particle motion in the supercrowded cytoplasm of pathogenic Acanthamoeba castellanii.

    PubMed

    Reverey, Julia F; Jeon, Jae-Hyung; Bao, Han; Leippe, Matthias; Metzler, Ralf; Selhuber-Unkel, Christine

    2015-01-01

    Acanthamoebae are free-living protists and human pathogens, whose cellular functions and pathogenicity strongly depend on the transport of intracellular vesicles and granules through the cytosol. Using high-speed live cell imaging in combination with single-particle tracking analysis, we show here that the motion of endogenous intracellular particles in the size range from a few hundred nanometers to several micrometers in Acanthamoeba castellanii is strongly superdiffusive and influenced by cell locomotion, cytoskeletal elements, and myosin II. We demonstrate that cell locomotion significantly contributes to intracellular particle motion, but is clearly not the only origin of superdiffusivity. By analyzing the contribution of microtubules, actin, and myosin II motors we show that myosin II is a major driving force of intracellular motion in A. castellanii. The cytoplasm of A. castellanii is supercrowded with intracellular vesicles and granules, such that significant intracellular motion can only be achieved by actively driven motion, while purely thermally driven diffusion is negligible. PMID:26123798

  12. Carbon metabolism of intracellular bacterial pathogens and possible links to virulence

    Microsoft Academic Search

    Wolfgang Eisenreich; Thomas Dandekar; Jürgen Heesemann; Werner Goebel

    2010-01-01

    New technologies such as high-throughput methods and 13C-isotopologue-profiling analysis are beginning to provide us with insight into the in vivo metabolism of microorganisms, especially in the host cell compartments that are colonized by intracellular bacterial pathogens. In this Review, we discuss the recent progress made in determining the major carbon sources and metabolic pathways used by model intracellular bacterial pathogens

  13. The P2X 7 receptor and intracellular pathogens: a continuing struggle

    Microsoft Academic Search

    Robson Coutinho-Silva; Gladys Corrêa; Ali Abdul Sater; David M. Ojcius

    2009-01-01

    The purinergic receptor, P2X7, has recently emerged as an important component of the innate immune response against microbial infections. Ligation of P2X7 by ATP can stimulate inflammasome activation and secretion of proinflammatory cytokines, but it can also lead directly to\\u000a killing of intracellular pathogens in infected macrophages and epithelial cells. Thus, while some intracellular pathogens\\u000a evade host defense responses by

  14. The Genome of the Obligate Intracellular Parasite Trachipleistophora hominis: New Insights into Microsporidian Genome Dynamics and Reductive Evolution

    PubMed Central

    Heinz, Eva; Williams, Tom A.; Nakjang, Sirintra; Noël, Christophe J.; Swan, Daniel C.; Goldberg, Alina V.; Harris, Simon R.; Weinmaier, Thomas; Markert, Stephanie; Becher, Dörte; Bernhardt, Jörg; Dagan, Tal; Hacker, Christian; Lucocq, John M.; Schweder, Thomas; Rattei, Thomas; Hall, Neil; Hirt, Robert P.; Embley, T. Martin

    2012-01-01

    The dynamics of reductive genome evolution for eukaryotes living inside other eukaryotic cells are poorly understood compared to well-studied model systems involving obligate intracellular bacteria. Here we present 8.5 Mb of sequence from the genome of the microsporidian Trachipleistophora hominis, isolated from an HIV/AIDS patient, which is an outgroup to the smaller compacted-genome species that primarily inform ideas of evolutionary mode for these enormously successful obligate intracellular parasites. Our data provide detailed information on the gene content, genome architecture and intergenic regions of a larger microsporidian genome, while comparative analyses allowed us to infer genomic features and metabolism of the common ancestor of the species investigated. Gene length reduction and massive loss of metabolic capacity in the common ancestor was accompanied by the evolution of novel microsporidian-specific protein families, whose conservation among microsporidians, against a background of reductive evolution, suggests they may have important functions in their parasitic lifestyle. The ancestor had already lost many metabolic pathways but retained glycolysis and the pentose phosphate pathway to provide cytosolic ATP and reduced coenzymes, and it had a minimal mitochondrion (mitosome) making Fe-S clusters but not ATP. It possessed bacterial-like nucleotide transport proteins as a key innovation for stealing host-generated ATP, the machinery for RNAi, key elements of the early secretory pathway, canonical eukaryotic as well as microsporidian-specific regulatory elements, a diversity of repetitive and transposable elements, and relatively low average gene density. Microsporidian genome evolution thus appears to have proceeded in at least two major steps: an ancestral remodelling of the proteome upon transition to intracellular parasitism that involved reduction but also selective expansion, followed by a secondary compaction of genome architecture in some, but not all, lineages. PMID:23133373

  15. Directed antigen delivery as a vaccine strategy for an intracellular bacterial pathogen

    NASA Astrophysics Data System (ADS)

    Bouwer, H. G. Archie; Alberti-Segui, Christine; Montfort, Megan J.; Berkowitz, Nathan D.; Higgins, Darren E.

    2006-03-01

    We have developed a vaccine strategy for generating an attenuated strain of an intracellular bacterial pathogen that, after uptake by professional antigen-presenting cells, does not replicate intracellularly and is readily killed. However, after degradation of the vaccine strain within the phagolysosome, target antigens are released into the cytosol for endogenous processing and presentation for stimulation of CD8+ effector T cells. Applying this strategy to the model intracellular pathogen Listeria monocytogenes, we show that an intracellular replication-deficient vaccine strain is cleared rapidly in normal and immunocompromised animals, yet antigen-specific CD8+ effector T cells are stimulated after immunization. Furthermore, animals immunized with the intracellular replication-deficient vaccine strain are resistant to lethal challenge with a virulent WT strain of L. monocytogenes. These studies suggest a general strategy for developing safe and effective, attenuated intracellular replication-deficient vaccine strains for stimulation of protective immune responses against intracellular bacterial pathogens. CD8+ T cell | replication-deficient | Listeria monocytogenes

  16. Intracellular survival mechanisms of Francisella tularensis, a stealth pathogen

    Microsoft Academic Search

    Anders Sjöstedt

    2006-01-01

    Research on the highly virulent and contagious, facultative intracellular bacterium Francisella tularensis has come into the limelight recently, but still little is known regarding its virulence mechanisms. This review summarizes recent studies on its intramacrophage survival mechanisms, some of which appear to be novel.

  17. A role for IgG immune complexes during infection with the intracellular pathogen Leishmania

    Microsoft Academic Search

    Suzanne A. Miles; Sean M. Conrad; Renata G. Alves; Selma M. B. Jeronimo; David M. Mosser

    2005-01-01

    We examined the role of immunoglobulin (Ig)G antibodies in mediating host defense to the intracellular parasite, Leishmania. We show that IgG not only fails to provide protection against this intracellular pathogen, but it actually contributes to disease progression. The J H strain of BALB\\/c mice, which lack IgG because they have a targeted deletion in the Ig heavy chain (J)

  18. Intracellular Pathogens within Alveolar Macrophages in a Patient with HIV Infection: Diagnostic Challenge.

    PubMed

    Shinha, Takashi; Badem, Olga

    2015-02-24

    In HIV-infected individuals, macrophages, the key defense effector cells, manifest defective activity in their interactions with a wide variety of opportunistic pathogens, including fungi and protozoa. Understanding the morphological characteristics of intracellular opportunistic pathogens in addition to their pathogenesis is of critical importance to provide optimal therapy, thereby decreasing morbidity and mortality in HIV-infected patients. We herein present a case of disseminated histoplasmosis confused with disseminated visceral leishmaniasis in an HIV-infected individual from Guyana who developed intracellular organisms within alveolar macrophages. PMID:25874069

  19. A Macrophage Subversion Factor Is Shared by Intracellular and Extracellular Pathogens

    PubMed Central

    Laubier, Aurélie; Bleves, Sophie; Blanc-Potard, Anne-Béatrice

    2015-01-01

    Pathogenic bacteria have developed strategies to adapt to host environment and resist host immune response. Several intracellular bacterial pathogens, including Salmonella enterica and Mycobacterium tuberculosis, share the horizontally-acquired MgtC virulence factor that is important for multiplication inside macrophages. MgtC is also found in pathogenic Pseudomonas species. Here we investigate for the first time the role of MgtC in the virulence of an extracellular pathogen, Pseudomonas aeruginosa. A P. aeruginosa mgtC mutant is attenuated in the systemic infection model of zebrafish embryos, and strikingly, the attenuated phenotype is dependent on the presence of macrophages. In ex vivo experiments, the P. aeruginosa mgtC mutant is more sensitive to macrophage killing than the wild-type strain. However, wild-type and mutant strains behave similarly toward macrophage killing when macrophages are treated with an inhibitor of the vacuolar proton ATPase. Importantly, P. aeruginosa mgtC gene expression is strongly induced within macrophages and phagosome acidification contributes to an optimal expression of the gene. Thus, our results support the implication of a macrophage intracellular stage during P. aeruginosa acute infection and suggest that Pseudomonas MgtC requires phagosome acidification to play its intracellular role. Moreover, we demonstrate that P. aeruginosa MgtC is required for optimal growth in Mg2+ deprived medium, a property shared by MgtC factors from intracellular pathogens and, under Mg2+ limitation, P. aeruginosa MgtC prevents biofilm formation. We propose that MgtC shares a similar function in intracellular and extracellular pathogens, which contributes to macrophage resistance and fine-tune adaptation to host immune response in relation to the different bacterial lifestyles. In addition, the phenotypes observed with the mgtC mutant in infection models can be mimicked in wild-type P. aeruginosa strain by producing a MgtC antagonistic peptide, thus highlighting MgtC as a promising new target for anti-virulence strategies. PMID:26080006

  20. Directed antigen delivery as a vaccine strategy for an intracellular bacterial pathogen

    E-print Network

    Higgins, Darren

    ), and Chlamydia trachomatis, cause sig- nificant morbidity and mortality worldwide. One successful vaccineDirected antigen delivery as a vaccine strategy for an intracellular bacterial pathogen H. G for review October 27, 2005) We have developed a vaccine strategy for generating an attenu- ated strain

  1. Delivery of host cell-directed therapeutics for intracellular pathogen clearance

    PubMed Central

    Collier, Michael A.; Gallovic, Matthew D.; Peine, Kevin J.; Duong, Anthony D.; Bachelder, Eric M.; Gunn, John S.; Schlesinger, Larry S.; Ainslie, Kristy M.

    2014-01-01

    Intracellular pathogens present a major health risk because of their innate ability to evade clearance. Their location within host cells and ability to react to the host environment by mutation or transcriptional changes often enables survival mechanisms to resist standard therapies. Host-directed drugs do not target the pathogen, minimizing the potential development of drug resistance; however, they can be difficult to deliver efficiently to intracellular sites. Vehicle delivery of host-mediated response drugs not only improves drug distribution and toxicity profiles, but can reduce the total amount of drug necessary to clear infection. In this article, we will review some host-directed drugs and current drug delivery techniques that can be used to efficiently clear intracellular infections. PMID:24134600

  2. Toll-like receptor–induced arginase 1 in macrophages thwarts effective immunity against intracellular pathogens

    PubMed Central

    El Kasmi, Karim C; Qualls, Joseph E; Pesce, John T; Smith, Amber M; Thompson, Robert W; Henao-Tamayo, Marcela; Basaraba, Randall J; König, Till; Schleicher, Ulrike; Koo, Mi-Sun; Kaplan, Gilla; Fitzgerald, Katherine A; Tuomanen, Elaine I; Orme, Ian M; Kanneganti, Thirumala-Devi; Bogdan, Christian; Wynn, Thomas A; Murray, Peter J

    2008-01-01

    Toll-like receptor (TLR) signaling in macrophages is required for antipathogen responses, including the biosynthesis of nitric oxide from arginine, and is essential for immunity to Mycobacterium tuberculosis, Toxoplasma gondii and other intracellular pathogens. Here we report a ‘loophole’ in the TLR pathway that is advantageous to these pathogens. Intracellular pathogens induced expression of the arginine hydrolytic enzyme arginase 1 (Arg1) in mouse macrophages through the TLR pathway. In contrast to diseases dominated by T helper type 2 (TH2) responses, TLR-mediated Arg1 induction was independent of the TH2-associated STAT6 pathway. Specific elimination of Arg1 in macrophages favored host survival in T. gondii infection and decreased lung bacterial load in tuberculosis infection. PMID:18978793

  3. Evolution to a Chronic Disease Niche Correlates with Increased Sensitivity to Tryptophan Availability for the Obligate Intracellular Bacterium Chlamydia pneumoniae

    PubMed Central

    Huston, Wilhelmina M.; Barker, Christopher J.; Chacko, Anu

    2014-01-01

    The chlamydiae are obligate intracellular parasites that have evolved specific interactions with their various hosts and host cell types to ensure their successful survival and consequential pathogenesis. The species Chlamydia pneumoniae is ubiquitous, with serological studies showing that most humans are infected at some stage in their lifetime. While most human infections are asymptomatic, C. pneumoniae can cause more-severe respiratory disease and pneumonia and has been linked to chronic diseases such as asthma, atherosclerosis, and even Alzheimer's disease. The widely dispersed animal-adapted C. pneumoniae strains cause an equally wide range of diseases in their hosts. It is emerging that the ability of C. pneumoniae to survive inside its target cells, including evasion of the host's immune attack mechanisms, is linked to the acquisition of key metabolites. Tryptophan and arginine are key checkpoint compounds in this host-parasite battle. Interestingly, the animal strains of C. pneumoniae have a slightly larger genome, enabling them to cope better with metabolite restrictions. It therefore appears that as the evolutionarily more ancient animal strains have evolved to infect humans, they have selectively become more “susceptible” to the levels of key metabolites, such as tryptophan. While this might initially appear to be a weakness, it allows these human C. pneumoniae strains to exquisitely sense host immune attack and respond by rapidly reverting to a persistent phase. During persistence, they reduce their metabolic levels, halting progression of their developmental cycle, waiting until the hostile external conditions have passed before they reemerge. PMID:24682324

  4. Discovery of putative small non-coding RNAs from the obligate intracellular bacterium Wolbachia pipientis.

    PubMed

    Woolfit, Megan; Algama, Manjula; Keith, Jonathan M; McGraw, Elizabeth A; Popovici, Jean

    2015-01-01

    Wolbachia pipientis is an endosymbiotic bacterium that induces a wide range of effects in its insect hosts, including manipulation of reproduction and protection against pathogens. Little is known of the molecular mechanisms underlying the insect-Wolbachia interaction, though it is likely to be mediated via the secretion of proteins or other factors. There is an increasing amount of evidence that bacteria regulate many cellular processes, including secretion of virulence factors, using small non-coding RNAs (sRNAs), but sRNAs have not previously been described from Wolbachia. We have used two independent approaches, one based on comparative genomics and the other using RNA-Seq data generated for gene expression studies, to identify candidate sRNAs in Wolbachia. We experimentally characterized the expression of one of these candidates in four Wolbachia strains, and showed that it is differentially regulated in different host tissues and sexes. Given the roles played by sRNAs in other host-associated bacteria, the conservation of the candidate sRNAs between different Wolbachia strains, and the sex- and tissue-specific differential regulation we have identified, we hypothesise that sRNAs may play a significant role in the biology of Wolbachia, and in particular in its interactions with its host. PMID:25739023

  5. Characterization of an Obligate Intracellular Bacterium in the Midgut Epithelium of the Bulrush Bug Chilacis typhae (Heteroptera, Lygaeidae, Artheneinae)?

    PubMed Central

    Kuechler, Stefan Martin; Dettner, Konrad; Kehl, Siegfried

    2011-01-01

    Many members of the suborder Heteroptera have symbiotic bacteria, which are usually found extracellularly in specific sacs or tubular outgrowths of the midgut or intracellularly in mycetomes. In this study, we describe the second molecular characterization of a symbiotic bacterium in a monophagous, seed-sucking stink bug of the family Lygaeidae (sensu stricto). Chilacis typhae possesses at the end of the first section of the midgut a structure which is composed of circularly arranged, strongly enlarged midgut epithelial cells. It is filled with an intracellular endosymbiont. This “mycetocytic belt” might represent an evolutionarily intermediate stage of the usual symbiotic structures found in stink bugs. Phylogenetic analysis based on the 16S rRNA and the groEL genes showed that the bacterium belongs to the Gammaproteobacteria, and it revealed a phylogenetic relationship with a secondary bacterial endosymbiont of Cimex lectularius and free-living plant pathogens such as Pectobacterium and Dickeya. The distribution and ultrastructure of the rod-shaped Chilacis endosymbiont were studied in adults and nymph stages using fluorescence in situ hybridization (FISH) and electron microscopy. The detection of symbionts at the anterior poles of developing eggs indicates that endosymbionts are transmitted vertically. A new genus and species name, “Candidatus Rohrkolberia cinguli,” is proposed for this newly characterized clade of symbiotic bacteria. PMID:21378044

  6. Intracellular antibody-bound pathogens stimulate immune signaling via the Fc receptor TRIM21.

    PubMed

    McEwan, William A; Tam, Jerry C H; Watkinson, Ruth E; Bidgood, Susanna R; Mallery, Donna L; James, Leo C

    2013-04-01

    During pathogen infection, antibodies can be carried into the infected cell, where they are detected by the ubiquitously expressed cytosolic antibody receptor TRIM21. Here we found that recognition of intracellular antibodies by TRIM21 activated immune signaling. TRIM21 catalyzed the formation of Lys63 (K63)-linked ubiquitin chains and stimulated the transcription factor pathways of NF-?B, AP-1, IRF3, IRF5 and IRF7. Activation resulted in the production of proinflammatory cytokines, modulation of natural killer stress ligands and induction of an antiviral state. Intracellular antibody signaling was abrogated by genetic deletion of TRIM21 and was restored by ectopic expression of TRIM21. The sensing of antibodies by TRIM21 was stimulated after infection by DNA or RNA nonenveloped viruses or intracellular bacteria. Thus, the antibody-TRIM21 detection system provides potent, comprehensive activation of the innate immune system independently of known pattern-recognition receptors. PMID:23455675

  7. Thioredoxin 80-Activated-Monocytes (TAMs) Inhibit the Replication of Intracellular Pathogens

    Microsoft Academic Search

    Ximena Cortes-Bratti; Eugénie Bassères; Fabiola Herrera-Rodriguez; Silvia Botero-Kleiven; Giuseppe Coppotelli; Jens B. Andersen; Maria G. Masucci; Arne Holmgren; Esteban Chaves-Olarte; Teresa Frisan; Javier Avila-Cariño

    2011-01-01

    BackgroundThioredoxin 80 (Trx80) is an 80 amino acid natural cleavage product of Trx, produced primarily by monocytes. Trx80 induces differentiation of human monocytes into a novel cell type, named Trx80-activated-monocytes (TAMs).Principal FindingsIn this investigation we present evidence for a role of TAMs in the control of intracellular bacterial infections. As model pathogens we have chosen Listeria monocytogenes and Brucella abortus

  8. Identification of a Quorum-Sensing Signal Molecule in the Facultative Intracellular Pathogen Brucella melitensis

    Microsoft Academic Search

    Bernard Taminiau; Mavis Daykin; Simon Swift; Maria-Laura Boschiroli; Anne Tibor; Pascal Lestrate; Xavier De Bolle; David O'Callaghan; Paul Williams; Jean-Jacques Letesson

    2002-01-01

    Brucella melitensis is a gram-negative alpha2-proteobacterium responsible for abortion in goats and for Malta fever in humans. This facultative intracellular pathogen invades and survives within both professional and nonprofessional phagocytes. A dichloromethane extract of spent culture supernatant from B. melitensis induces bioluminescence in an Escherichia coli acyl-homoserine lactone (acyl-HSL) biosensor strain based upon the activity of the LasR protein of

  9. The complete genomic sequence of Mycoplasma penetrans, an intracellular bacterial pathogen in humans

    Microsoft Academic Search

    Yuko Sasaki; Jun Ishikawa; Atsushi Yamashita; Kenshiro Oshima; Tsuyoshi Kenri; Keiko Furuya; Chie Yoshino; Atsuko Horino; Tadayoshi Shiba; Tsuguo Sasaki; Masahira Hattori

    2002-01-01

    The complete genomic sequence of an intracellular bacterial pathogen, Mycoplasma penetrans HF-2 strain, was determined. The HF-2 genome consists of a 1 358 633 bp single circular chromosome con- taining 1038 predicted coding sequences (CDSs), one set of rRNA genes and 30 tRNA genes. Among the 1038 CDSs, 264 predicted proteins are common to the Mycoplasmataceae sequenced thus far and

  10. Molecular methods to investigate adhesion, transmigration, invasion and intracellular survival of the foodborne pathogen Campylobacter jejuni.

    PubMed

    Backert, Steffen; Hofreuter, Dirk

    2013-10-01

    Campylobacter jejuni is a spiral-shaped Gram-negative pathogen and major agent of gastrointestinal foodborne illness in humans worldwide. This pathogen encodes numerous described pathogenicity-associated factors involved in important processes including bacterial adhesion to, transmigration across, invasion into and intracellular survival within intestinal epithelial cells. This review article highlights various molecular techniques applied in the studies of each of these individual steps of C. jejuni host cell interactions in vitro including gentamicin protection assay, chemotaxis and motility assays, transwell and intracellular survival assays, G-Lisa, siRNA knockdown, immunohistochemistry, immunofluorescence, electron microscopy and luciferase reporter assays. We discuss the strengths and limitations of the methods as well as the different cell model systems applied. Future work should employ new technologies including modern microscopic, proteomics-based and cell signaling approaches to identify and characterise novel virulence mechanisms, which are crucial to provide fresh insights into the diversity of strategies employed by this important pathogen to cause disease. PMID:23872466

  11. Identification of a Quorum-Sensing Signal Molecule in the Facultative Intracellular Pathogen Brucella melitensis

    PubMed Central

    Taminiau, Bernard; Daykin, Mavis; Swift, Simon; Boschiroli, Maria-Laura; Tibor, Anne; Lestrate, Pascal; De Bolle, Xavier; O'Callaghan, David; Williams, Paul; Letesson, Jean-Jacques

    2002-01-01

    Brucella melitensis is a gram-negative alpha2-proteobacterium responsible for abortion in goats and for Malta fever in humans. This facultative intracellular pathogen invades and survives within both professional and nonprofessional phagocytes. A dichloromethane extract of spent culture supernatant from B. melitensis induces bioluminescence in an Escherichia coli acyl-homoserine lactone (acyl-HSL) biosensor strain based upon the activity of the LasR protein of Pseudomonas aeruginosa. HPLC fractionation of the extract, followed by mass spectrometry, identified the major active molecule as N-dodecanoylhomoserine lactone (C12-HSL). This is the first report of the production of an acyl-HSL by an intracellular pathogen. The addition of synthetic C12-HSL to an early log phase culture of either B. melitensis or Brucella suis 1330 reduces the transcription of the virB operon, which contains virulence genes known to be required for intracellular survival. This mimics events seen during the stationary phase of growth and suggests that quorum sensing may play a role in the control of virulence in Brucella. PMID:12010991

  12. Identification of a quorum-sensing signal molecule in the facultative intracellular pathogen Brucella melitensis.

    PubMed

    Taminiau, Bernard; Daykin, Mavis; Swift, Simon; Boschiroli, Maria-Laura; Tibor, Anne; Lestrate, Pascal; De Bolle, Xavier; O'Callaghan, David; Williams, Paul; Letesson, Jean-Jacques

    2002-06-01

    Brucella melitensis is a gram-negative alpha2-proteobacterium responsible for abortion in goats and for Malta fever in humans. This facultative intracellular pathogen invades and survives within both professional and nonprofessional phagocytes. A dichloromethane extract of spent culture supernatant from B. melitensis induces bioluminescence in an Escherichia coli acyl-homoserine lactone (acyl-HSL) biosensor strain based upon the activity of the LasR protein of Pseudomonas aeruginosa. HPLC fractionation of the extract, followed by mass spectrometry, identified the major active molecule as N-dodecanoylhomoserine lactone (C12-HSL). This is the first report of the production of an acyl-HSL by an intracellular pathogen. The addition of synthetic C12-HSL to an early log phase culture of either B. melitensis or Brucella suis 1330 reduces the transcription of the virB operon, which contains virulence genes known to be required for intracellular survival. This mimics events seen during the stationary phase of growth and suggests that quorum sensing may play a role in the control of virulence in Brucella. PMID:12010991

  13. A Transcriptomic Network Identified in Uninfected Macrophages Responding to Inflammation Controls Intracellular Pathogen Survival

    PubMed Central

    Beattie, Lynette; d’El-Rei Hermida, Micely; Moore, John W.J.; Maroof, Asher; Brown, Najmeeyah; Lagos, Dimitris; Kaye, Paul M.

    2013-01-01

    Summary Intracellular pathogens modulate host cell function to promote their survival. However, in vitro infection studies do not account for the impact of host-derived inflammatory signals. Examining the response of liver-resident macrophages (Kupffer cells) in mice infected with the parasite Leishmania donovani, we identified a transcriptomic network operating in uninfected Kupffer cells exposed to inflammation but absent from Kupffer cells from the same animal that contained intracellular Leishmania. To test the hypothesis that regulated expression of genes within this transcriptomic network might impact parasite survival, we pharmacologically perturbed the activity of retinoid X receptor alpha (RXR?), a key hub within this network, and showed that this intervention enhanced the innate resistance of Kupffer cells to Leishmania infection. Our results illustrate a broadly applicable strategy for understanding the host response to infection in vivo and identify Rxra as the hub of a gene network controlling antileishmanial resistance. PMID:24034621

  14. Identification of intracellular and plasma membrane calcium channel homologues in pathogenic parasites.

    PubMed

    Prole, David L; Taylor, Colin W

    2011-01-01

    Ca(2+) channels regulate many crucial processes within cells and their abnormal activity can be damaging to cell survival, suggesting that they might represent attractive therapeutic targets in pathogenic organisms. Parasitic diseases such as malaria, leishmaniasis, trypanosomiasis and schistosomiasis are responsible for millions of deaths each year worldwide. The genomes of many pathogenic parasites have recently been sequenced, opening the way for rational design of targeted therapies. We analyzed genomes of pathogenic protozoan parasites as well as the genome of Schistosoma mansoni, and show the existence within them of genes encoding homologues of mammalian intracellular Ca(2+) release channels: inositol 1,4,5-trisphosphate receptors (IP(3)Rs), ryanodine receptors (RyRs), two-pore Ca(2+) channels (TPCs) and intracellular transient receptor potential (Trp) channels. The genomes of Trypanosoma, Leishmania and S. mansoni parasites encode IP(3)R/RyR and Trp channel homologues, and that of S. mansoni additionally encodes a TPC homologue. In contrast, apicomplexan parasites lack genes encoding IP(3)R/RyR homologues and possess only genes encoding TPC and Trp channel homologues (Toxoplasma gondii) or Trp channel homologues alone. The genomes of parasites also encode homologues of mammalian Ca(2+) influx channels, including voltage-gated Ca(2+) channels and plasma membrane Trp channels. The genome of S. mansoni also encodes Orai Ca(2+) channel and STIM Ca(2+) sensor homologues, suggesting that store-operated Ca(2+) entry may occur in this parasite. Many anti-parasitic agents alter parasite Ca(2+) homeostasis and some are known modulators of mammalian Ca(2+) channels, suggesting that parasite Ca(2+) channel homologues might be the targets of some current anti-parasitic drugs. Differences between human and parasite Ca(2+) channels suggest that pathogen-specific targeting of these channels may be an attractive therapeutic prospect. PMID:22022573

  15. Antigen selection based on expression levels during infection facilitates vaccine development for an intracellular pathogen

    PubMed Central

    Rollenhagen, Claudia; Sörensen, Meike; Rizos, Konstantin; Hurvitz, Robert; Bumann, Dirk

    2004-01-01

    Vaccines effective against intracellular pathogens could save the lives of millions of people every year, but vaccine development has been hampered by the slow largely empirical search for protective antigens. In vivo highly expressed antigens might represent a small attractive antigen subset that could be rapidly evaluated, but experimental evidence supporting this rationale, as well as practical strategies for its application, is largely lacking because of technical difficulties. Here, we used Salmonella strains expressing differential amounts of a fluorescent model antigen during infection to show that, in a mouse typhoid fever model, CD4 T cells preferentially recognize abundant Salmonella antigens. To identify a large number of natural Salmonella antigens with high expression levels during infection, we used a quantitative in vivo screening strategy. Immunization studies with five particularly attractive candidates revealed two highly protective antigens that might permit the development of an improved typhoid fever vaccine. In conclusion, we have established a rationale and an experimental strategy that will substantially facilitate vaccine development for Salmonella and possibly other intracellular pathogens. PMID:15173591

  16. Comparative genome analysis of wheat blue dwarf phytoplasma, an obligate pathogen that causes wheat blue dwarf disease in China.

    PubMed

    Chen, Wang; Li, Yan; Wang, Qiang; Wang, Nan; Wu, Yunfeng

    2014-01-01

    Wheat blue dwarf (WBD) disease is an important disease that has caused heavy losses in wheat production in northwestern China. This disease is caused by WBD phytoplasma, which is transmitted by Psammotettix striatus. Until now, no genome information about WBD phytoplasma has been published, seriously restricting research on this obligate pathogen. In this paper, we report a new sequencing and assembling strategy for phytoplasma genome projects. This strategy involves differential centrifugation, pulsed-field gel electrophoresis, whole genome amplification, shotgun sequencing, de novo assembly, screening of contigs from phytoplasma and the connection of phytoplasma contigs. Using this scheme, the WBD phytoplasma draft genome was obtained. It was comprised of six contigs with a total size of 611,462 bp, covering ?94% of the chromosome. Five-hundred-twenty-five protein-coding genes, two operons for rRNA genes and 32 tRNA genes were identified. Comparative genome analyses between WBD phytoplasma and other phytoplasmas were subsequently carried out. The results showed that extensive arrangements and inversions existed among the WBD, OY-M and AY-WB phytoplasma genomes. Most protein-coding genes in WBD phytoplasma were found to be homologous to genes from other phytoplasmas; only 22 WBD-specific genes were identified. KEGG pathway analysis indicated that WBD phytoplasma had strongly reduced metabolic capabilities. However, 46 transporters were identified, which were involved with dipeptides/oligopeptides, spermidine/putrescine, cobalt and Mn/Zn transport, and so on. A total of 37 secreted proteins were encoded in the WBD phytoplasma chromosome and plasmids. Of these, three secreted proteins were similar to the reported phytoplasma virulence factors TENGU, SAP11 and SAP54. In addition, WBD phytoplasma possessed several proteins that were predicted to play a role in its adaptation to diverse environments. These results will provide clues for research on the pathogenic mechanisms of WBD phytoplasma and will also provide a perspective about the genome sequencing of other phytoplasmas and obligate organisms. PMID:24798075

  17. Search for MicroRNAs Expressed by Intracellular Bacterial Pathogens in Infected Mammalian Cells

    PubMed Central

    Furuse, Yuki; Finethy, Ryan; Saka, Hector A.; Xet-Mull, Ana M.; Sisk, Dana M.; Smith, Kristen L. Jurcic; Lee, Sunhee; Coers, Jörn; Valdivia, Raphael H.; Tobin, David M.; Cullen, Bryan R.

    2014-01-01

    MicroRNAs are expressed by all multicellular organisms and play a critical role as post-transcriptional regulators of gene expression. Moreover, different microRNA species are known to influence the progression of a range of different diseases, including cancer and microbial infections. A number of different human viruses also encode microRNAs that can attenuate cellular innate immune responses and promote viral replication, and a fungal pathogen that infects plants has recently been shown to express microRNAs in infected cells that repress host cell immune responses and promote fungal pathogenesis. Here, we have used deep sequencing of total expressed small RNAs, as well as small RNAs associated with the cellular RNA-induced silencing complex RISC, to search for microRNAs that are potentially expressed by intracellular bacterial pathogens and translocated into infected animal cells. In the case of Legionella and Chlamydia and the two mycobacterial species M. smegmatis and M. tuberculosis, we failed to detect any bacterial small RNAs that had the characteristics expected for authentic microRNAs, although large numbers of small RNAs of bacterial origin could be recovered. However, a third mycobacterial species, M. marinum, did express an ?23-nt small RNA that was bound by RISC and derived from an RNA stem-loop with the characteristics expected for a pre-microRNA. While intracellular expression of this candidate bacterial microRNA was too low to effectively repress target mRNA species in infected cultured cells in vitro, artificial overexpression of this potential bacterial pre-microRNA did result in the efficient repression of a target mRNA. This bacterial small RNA therefore represents the first candidate microRNA of bacterial origin. PMID:25184567

  18. Host-Pathogen Checkpoints and Population Bottlenecks in Persistent and Intracellular Uropathogenic E. coli Bladder Infection

    PubMed Central

    Hannan, Thomas J.; Totsika, Makrina; Mansfield, Kylie J.; Moore, Kate H.; Schembri, Mark A.; Hultgren, Scott J.

    2013-01-01

    Bladder infections affect millions of people yearly, and recurrent symptomatic infections (cystitis) are very common. The rapid increase in infections caused by multi-drug resistant uropathogens threatens to make recurrent cystitis an increasingly troubling public health concern. Uropathogenic E. coli (UPEC) cause the vast majority of bladder infections. Upon entry into the lower urinary tract, UPEC face obstacles to colonization that constitute population bottlenecks, reducing diversity and selecting for fit clones. A critical mucosal barrier to bladder infection is the epithelium (urothelium). UPEC bypass this barrier when they invade urothelial cells and form intracellular bacterial communities (IBCs), a process which requires type 1 pili. IBCs are transient in nature, occurring primarily during acute infection. Chronic bladder infection is common and can be either latent, in the form of the Quiescent Intracellular Reservoir (QIR), or active, in the form of asymptomatic bacteriuria (ASB/ABU) or chronic cystitis. In mice, the fate of bladder infection: QIR, ASB, or chronic cystitis, is determined within the first 24 hours of infection and constitutes a putative host-pathogen mucosal checkpoint that contributes to susceptibility to recurrent cystitis. Knowledge of these checkpoints and bottlenecks is critical for our understanding of bladder infection and efforts to devise novel therapeutic strategies. PMID:22404313

  19. A role for IgG immune complexes during infection with the intracellular pathogen Leishmania

    PubMed Central

    Miles, Suzanne A.; Conrad, Sean M.; Alves, Renata G.; Jeronimo, Selma M.B.; Mosser, David M.

    2005-01-01

    We examined the role of immunoglobulin (Ig)G antibodies in mediating host defense to the intracellular parasite, Leishmania. We show that IgG not only fails to provide protection against this intracellular pathogen, but it actually contributes to disease progression. The JH strain of BALB/c mice, which lack IgG because they have a targeted deletion in the Ig heavy chain (J) locus, were more resistant to infection with Leishmania major than were normal BALB/c mice. However, the passive administration of anti-Leishmania IgG caused JH mice to develop large lesions containing high numbers of parasites. Antibody administration correlated with an increase in interleukin (IL) 10 production in lesions, and blocking the murine IL-10 receptor prevented antibody-mediated disease exacerbation. In human patients with active visceral leishmaniasis, high IgG levels are predictive of disease. Patients with ongoing disease had high IgG antibody titers and no delayed-type hypersensitivity (DTH) responses to Leishmania antigens. This pattern was reversed upon disease resolution after treatment, resulting in a decrease in total IgG, which was accompanied by a progressive increase in DTH responsiveness. We conclude that IgG can cause a novel form of immune enhancement due to its ability to induce IL-10 production from macrophages. PMID:15753208

  20. Global Analysis of Quorum Sensing Targets in the Intracellular Pathogen Brucella melitensis 16 M

    PubMed Central

    2010-01-01

    Many pathogenic bacteria use a regulatory process termed quorum sensing (QS) to produce and detect small diffusible molecules to synchronize gene expression within a population. In Gram-negative bacteria, the detection of, and response to, these molecules depends on transcriptional regulators belonging to the LuxR family. Such a system has been discovered in the intracellular pathogen Brucella melitensis, a Gram-negative bacterium responsible for brucellosis, a worldwide zoonosis that remains a serious public health concern in countries were the disease is endemic. Genes encoding two LuxR-type regulators, VjbR and BabR, have been identified in the genome of B. melitensis 16 M. A ?vjbR mutant is highly attenuated in all experimental models of infection tested, suggesting a crucial role for QS in the virulence of Brucella. At present, no function has been attributed to BabR. The experiments described in this report indicate that 5% of the genes in the B. melitensis 16 M genome are regulated by VjbR and/or BabR, suggesting that QS is a global regulatory system in this bacterium. The overlap between BabR and VjbR targets suggest a cross-talk between these two regulators. Our results also demonstrate that VjbR and BabR regulate many genes and/or proteins involved in stress response, metabolism, and virulence, including those potentially involved in the adaptation of Brucella to the oxidative, pH, and nutritional stresses encountered within the host. These findings highlight the involvement of QS as a major regulatory system in Brucella and lead us to suggest that this regulatory system could participate in the spatial and sequential adaptation of Brucella strains to the host environment. PMID:20387905

  1. Molecular Evolutionary Consequences of Niche Restriction in Francisella tularensis, a Facultative Intracellular Pathogen

    PubMed Central

    Larsson, Pär; Elfsmark, Daniel; Svensson, Kerstin; Wikström, Per; Forsman, Mats; Brettin, Thomas; Keim, Paul; Johansson, Anders

    2009-01-01

    Francisella tularensis is a potent mammalian pathogen well adapted to intracellular habitats, whereas F. novicida and F. philomiragia are less virulent in mammals and appear to have less specialized lifecycles. We explored adaptations within the genus that may be linked to increased host association, as follows. First, we determined the genome sequence of F. tularensis subsp. mediasiatica, the only subspecies that had not been previously sequenced. This genome, and those of 12 other F. tularensis isolates, were then compared to the genomes of F. novicida (three isolates) and F. philomiragia (one isolate). Signs of homologous recombination were found in ?19.2% of F. novicida and F. philomiragia genes, but none among F. tularensis genomes. In addition, random insertions of insertion sequence elements appear to have provided raw materials for secondary adaptive mutations in F. tularensis, e.g. for duplication of the Francisella Pathogenicity Island and multiplication of a putative glycosyl transferase gene. Further, the five major genetic branches of F. tularensis seem to have converged along independent routes towards a common gene set via independent losses of gene functions. Our observations suggest that despite an average nucleotide identity of >97%, F. tularensis and F. novicida have evolved as two distinct population lineages, the former characterized by clonal structure with weak purifying selection, the latter by more frequent recombination and strong purifying selection. F. tularensis and F. novicida could be considered the same bacterial species, given their high similarity, but based on the evolutionary analyses described in this work we propose retaining separate species names. PMID:19521508

  2. Neutrophils exert a suppressive effect on Th1 responses to intracellular pathogen Brucella abortus.

    PubMed

    Barquero-Calvo, Elías; Martirosyan, Anna; Ordoñez-Rueda, Diana; Arce-Gorvel, Vilma; Alfaro-Alarcón, Alejandro; Lepidi, Hubert; Malissen, Bernard; Malissen, Marie; Gorvel, Jean-Pierre; Moreno, Edgardo

    2013-02-01

    Polymorphonuclear neutrophils (PMNs) are the first line of defense against microbial pathogens. In addition to their role in innate immunity, PMNs may also regulate events related to adaptive immunity. To investigate the influence of PMNs in the immune response during chronic bacterial infections, we explored the course of brucellosis in antibody PMN-depleted C57BL/6 mice and in neutropenic mutant Genista mouse model. We demonstrate that at later times of infection, Brucella abortus is killed more efficiently in the absence of PMNs than in their presence. The higher bacterial removal was concomitant to the: i) comparatively reduced spleen swelling; ii) augmented infiltration of epithelioid histiocytes corresponding to macrophages/dendritic cells (DCs); iii) higher recruitment of monocytes and monocyte/DCs phenotype; iv) significant activation of B and T lymphocytes, and v) increased levels of INF-? and negligible levels of IL4 indicating a balance of Th1 over Th2 response. These results reveal that PMNs have an unexpected influence in dampening the immune response against intracellular Brucella infection and strengthen the notion that PMNs actively participate in regulatory circuits shaping both innate and adaptive immunity. PMID:23458832

  3. Rapid pathogen-induced apoptosis: a mechanism used by dendritic cells to limit intracellular replication of Legionella pneumophila.

    PubMed

    Nogueira, Catarina V; Lindsten, Tullia; Jamieson, Amanda M; Case, Christopher L; Shin, Sunny; Thompson, Craig B; Roy, Craig R

    2009-06-01

    Dendritic cells (DCs) are specialized phagocytes that internalize exogenous antigens and microbes at peripheral sites, and then migrate to lymphatic organs to display foreign peptides to naïve T cells. There are several examples where DCs have been shown to be more efficient at restricting the intracellular replication of pathogens compared to macrophages, a property that could prevent DCs from enhancing pathogen dissemination. To understand DC responses to pathogens, we investigated the mechanisms by which mouse DCs are able to restrict replication of the intracellular pathogen Legionella pneumophila. We show that both DCs and macrophages have the ability to interfere with L. pneumophila replication through a cell death pathway mediated by caspase-1 and Naip5. L. pneumophila that avoided Naip5-dependent responses, however, showed robust replication in macrophages but remained unable to replicate in DCs. Apoptotic cell death mediated by caspase-3 was found to occur much earlier in DCs following infection by L. pneumophila compared to macrophages infected similarly. Eliminating the pro-apoptotic proteins Bax and Bak or overproducing the anti-apoptotic protein Bcl-2 were both found to restore L. pneumophila replication in DCs. Thus, DCs have a microbial response pathway that rapidly activates apoptosis to limit pathogen replication. PMID:19521510

  4. Maintenance of intracellular hypoxia and adequate heat shock response are essential requirements for pathogenicity and virulence of Entamoeba histolytica.

    PubMed

    Santos, Fabiola; Nequiz, Mario; Hernández-Cuevas, Nora Adriana; Hernández, Kahory; Pineda, Erika; Encalada, Rusely; Guillén, Nancy; Luis-García, Erika; Saralegui, Andrés; Saavedra, Emma; Pérez-Tamayo, Ruy; Olivos-García, Alfonso

    2015-07-01

    Adhesion to cells, cytotoxicity and proteolysis are functions required for virulence and pathogenicity of?Entamoeba histolytica. However, there was no correlation between these in vitro functions and the early elimination of non-pathogenic E.?dispar and non-virulent E.?histolytica (nvEh) in experimental amoebic liver abscesses developed in hamsters. Thus, additional functions may be involved in amoebic pathogenicity and virulence. In the present study, an integral experimental assessment, including innovative technologies for analyses of amoebal pathophysiology, cell biology, biochemistry and transcriptomics, was carried out to elucidate whether other cellular processes are involved in amoebal pathogenicity and virulence. In comparison with virulent E.?histolytica, the data indicated that the main reasons for the early clearance of nvEh from hamster liver are decreased intracellular H2 O2 detoxification rate and deficient heat shock protein expression, whereas for E.?dispar, it is a relatively lower capacity for O2 reduction. Therefore, maintenance of an intracellular hypoxic environment combined with the induction of an adequate parasite response to oxidative stress are essential requirements for Entamoeba survival in the liver, and therefore for pathogenicity. PMID:25611463

  5. The essential role of the CopN protein in Chlamydia pneumoniae intracellular growth

    Microsoft Academic Search

    Jin Huang; Cammie F. Lesser; Stephen Lory

    2008-01-01

    Bacterial virulence determinants can be identified, according to the molecular Koch's postulates, if inactivation of a gene associated with a suspected virulence trait results in a loss in pathogenicity. This approach is commonly used with genetically tractable organisms. However, the current lack of tools for targeted gene disruptions in obligate intracellular microbial pathogens seriously hampers the identification of their virulence

  6. Multilocus sequence analysis (MLSA) of 'Rickettsiella agriotidis', an intracellular bacterial pathogen of Agriotes wireworms.

    PubMed

    Schuster, Christina; Kleespies, Regina G; Ritter, Claudia; Feiertag, Simon; Leclerque, Andreas

    2013-01-01

    Wireworms, the polyphagous larvae of click beetles belonging to the genus Agriotes (Coleoptera: Elateridae) are severe and widespread agricultural pests that affect numerous crops globally. A new bacterial specimen identified in diseased wireworms had previously been shown by microscopy and 16S ribosomal RNA (rRNA) gene-based phylogenetic reconstruction to belong to the taxonomic genus Rickettsiella (Gammaproteobacteria) that comprises intracellular bacteria associated with and typically pathogenic for a wide range of arthropods. Going beyond these earlier results obtained from rRNA phylogenies, multilocus sequence analysis (MLSA) using a four marker scheme has been employed in the molecular taxonomic characterization of the new Rickettsiella pathotype, referred to as 'Rickettsiella agriotidis'. In combination with likelihood-based significance testing, the MLSA approach demonstrated the close phylogenetic relationship of 'R. agriotidis' to the pathotypes 'Rickettsiella melolonthae' and 'Rickettsiella tipulae', i.e., subjective synonyms of the nomenclatural type species, Rickettsiella popilliae. 'R. agriotidis' forms, therefore, part of a Rickettsiella pathotype complex that most likely represents the species R. popilliae. As there are currently no genetic data available from the R. popilliae type strain, the respective assignment cannot be corroborated directly. However, an alternative taxonomic assignment to the species Rickettsiella grylli has been positively ruled out by significance testing. MLSA has been shown to provide a more powerful tool for taxonomic delineation within the genus Rickettsiella as compared to 16S rRNA phylogenetics. However, the limitations of the present MLSA scheme for the sub-species level classification of 'R. agriotidis' and further R. popilliae synonyms has been critically evaluated. PMID:23007524

  7. Intracellular Growth of Legionella pneumophila in Dictyostelium discoideum, a System for Genetic Analysis of Host-Pathogen Interactions

    PubMed Central

    Solomon, Jonathan M.; Rupper, Adam; Cardelli, James A.; Isberg, Ralph R.

    2000-01-01

    Conditions were established in which Legionella pneumophila, an intracellular bacterial pathogen, could replicate within the unicellular organism Dictyostelium discoideum. By several criteria, L. pneumophila grew by the same mechanism within D. discoideum as it does in amoebae and macrophages. Bacteria grew within membrane-bound vesicles associated with rough endoplasmic reticulum, and L. pneumophila dot/icm mutants, blocked for growth in macrophages and amoebae, also did not grow in D. discoideum. Internalized L. pneumophila avoided degradation by D. discoideum and showed evidence of reduced fusion with endocytic compartments. The ability of L. pneumophila to grow within D. discoideum depended on the growth state of the cells. D. discoideum grown as adherent monolayers was susceptible to L. pneumophila infection and to contact-dependent cytotoxicity during high-multiplicity infections, whereas D. discoideum grown in suspension was relatively resistant to cytotoxicity and did not support intracellular growth. Some known D. discoideum mutants were examined for their effect on growth of L. pneumophila. The coronin mutant and the myoA/B double myosin I mutant were more permissive than wild-type strains for intracellular growth. Growth of L. pneumophila in a G? mutant was slightly reduced compared to the parent strain. This work demonstrates the usefulness of the L. pneumophila-D. discoideum system for genetic analysis of host-pathogen interactions. PMID:10768992

  8. CD40 Signaling in Macrophages Induces Activity against an Intracellular Pathogen Independently of Gamma Interferon and Reactive Nitrogen Intermediates

    PubMed Central

    Andrade, Rosa M.; Portillo, Jose-Andres C.; Wessendarp, Matthew; Subauste, Carlos S.

    2005-01-01

    Gamma interferon (IFN-?) is the major inducer of classical activation of macrophages. Classically activated mouse macrophages acquire antimicrobial activity that is largely dependent on the production of reactive nitrogen intermediates. However, protection against important intracellular pathogens can take place in the absence of IFN-? and nitric oxide synthase 2 (NOS2). Using Toxoplasma gondii as a model, we investigated if CD40 signaling generates mouse macrophages with effector function against an intracellular pathogen despite the absence of priming with IFN-? and lack of production of reactive nitrogen intermediates. CD40-stimulated macrophages acquired anti-T. gondii activity that was not inhibited by a neutralizing anti-IFN-? monoclonal antibody but was ablated by the neutralization of tumor necrosis factor alpha (TNF-?). Moreover, while the induction of anti-T. gondii activity in response to CD40 stimulation was unimpaired in macrophages from IFN-??/? mice, macrophages from TNF receptor 1/2?/? mice failed to respond to CD40 engagement. In contrast to IFN-?-lipopolysaccharide, CD40 stimulation did not induce NOS2 expression and did not trigger production of reactive nitrogen intermediates. Neither NG-monomethyl-l-arginine nor diphenyleneiodonium chloride affected the induction of anti-T. gondii activity in response to CD40. Finally, macrophages from NOS2?/? mice acquired anti-T. gondii activity in response to CD40 stimulation that was similar to that of macrophages from wild-type mice. These results demonstrate that CD40 induces the antimicrobial activity of macrophages against an intracellular pathogen despite the lack of two central features of classically activated macrophages: priming with IFN-? and production of reactive nitrogen intermediates. PMID:15845519

  9. CD4+ T cells rely on a cytokine gradient to control intracellular pathogens beyond sites of antigen presentation.

    PubMed

    Müller, Andreas J; Filipe-Santos, Orchidée; Eberl, Gerard; Aebischer, Toni; Späth, Gerald F; Bousso, Philippe

    2012-07-27

    Effector T cells are critical for clearance of pathogens from sites of infection. Like cytotoxic CD8(+) T cells, CD4(+) helper T cells have been shown to deliver effector molecules directionally toward the immunological synapse, suggesting that infected cells need to be engaged individually to receive effector signals. In contrast, we show here that CD4(+) T cells stably contacted a minority of infected cells, yet these interactions triggered intracellular defense mechanisms in bystander cells in vivo. By using a functional read-out, we provide evidence that this effector bystander activity extends via a gradient of IFN-? more than 80 ?m beyond the site of antigen presentation, promoting pathogen clearance in the absence of immunological synapse formation. Our results thus demonstrate that CD4(+) T cells can exert their protective activity by engaging a minority of infected cells. PMID:22727490

  10. Coinfection of tick cell lines has variable effects on replication of intracellular bacterial and viral pathogens

    PubMed Central

    Moniuszko, Anna; Rückert, Claudia; Alberdi, M. Pilar; Barry, Gerald; Stevenson, Brian; Fazakerley, John K.; Kohl, Alain; Bell-Sakyi, Lesley

    2014-01-01

    Ticks transmit various human and animal microbial pathogens and may harbour more than one pathogen simultaneously. Both viruses and bacteria can trigger, and may subsequently suppress, vertebrate host and arthropod vector anti-microbial responses. Microbial coinfection of ticks could lead to an advantage or disadvantage for one or more of the microorganisms. In this preliminary study, cell lines derived from the ticks Ixodes scapularis and Ixodes ricinus were infected sequentially with 2 arthropod-borne pathogens, Borrelia burgdorferi s.s., Ehrlichia ruminantium, or Semliki Forest virus (SFV), and the effect of coinfection on the replication of these pathogens was measured. Prior infection of tick cell cultures with the spirochaete B. burgdorferi enhanced subsequent replication of the rickettsial pathogen E. ruminantium whereas addition of spirochaetes to cells infected with E. ruminantium had no effect on growth of the latter. Both prior and subsequent presence of B. burgdorferi also had a positive effect on SFV replication. Presence of E. ruminantium or SFV had no measurable effect on B. burgdorferi growth. In tick cells infected first with E. ruminantium and then with SFV, virus replication was significantly higher across all time points measured (24, 48, 72 h post infection), while presence of the virus had no detectable effect on bacterial growth. When cells were infected first with SFV and then with E. ruminantium, there was no effect on replication of either pathogen. The results of this preliminary study indicate that interplay does occur between different pathogens during infection of tick cells. Further study is needed to determine if this results from direct pathogen–pathogen interaction or from effects on host cell defences, and to determine if these observations also apply in vivo in ticks. If presence of one pathogen in the tick vector results in increased replication of another, this could have implications for disease transmission and incidence. PMID:24685441

  11. P2X7 Receptor Regulates Internalization of Antimicrobial Peptide LL-37 by Human Macrophages That Promotes Intracellular Pathogen Clearance.

    PubMed

    Tang, Xiao; Basavarajappa, Devaraj; Haeggström, Jesper Z; Wan, Min

    2015-08-01

    Bioactive peptide LL-37/hCAP18, the only human member of the cathelicidin family, plays important roles in killing various pathogens, as well as in immune modulation. We demonstrate that LL-37 is internalized by human macrophages in a time-, dose-, temperature-, and peptide sequence-dependent endocytotic process. Both clathrin- and caveolae/lipid raft-mediated endocytosis pathways are involved in LL-37 internalization. We find that the P2X7 receptor (P2X7R) plays an important role in LL-37 internalization by human macrophages because significantly less internalized LL-37 was detected in macrophages pretreated with P2X7R antagonists or, more specifically, in differentiated THP-1 cells in which the P2X7R gene had been silenced. Furthermore, this P2X7R-mediated LL-37 internalization is primarily connected to the clathrin-mediated endocytosis pathway. In addition, our results demonstrate that internalized LL-37 traffics to endosomes and lysosomes and contributes to intracellular clearance of bacteria by human macrophages, coinciding with increased reactive oxygen species and lysosome formation. Finally, we show that human macrophages have the potential to import LL-37 released from activated human neutrophils. In conclusion, our study unveils a novel mechanism by which human macrophages internalize antimicrobial peptides to improve their intracellular pathogen clearance. PMID:26116509

  12. Type II cytokines impair host defense against an intracellular fungal pathogen by amplifying macrophage generation of IL-33.

    PubMed

    Verma, A; Kroetz, D N; Tweedle, J L; Deepe, G S

    2015-03-01

    Interleukin (IL)-4 subverts protective immunity to multiple intracellular pathogens, including the fungus Histoplasma capsulatum. Previously, we reported that H. capsulatum-challenged CCR2(-/-) mice manifest elevated pulmonary fungal burden owing to exaggerated IL-4. Paradoxical to our anticipation in IL-33 driving IL-4, we discovered that the latter prompted IL-33 in mutant mice. In infected CCR2(-/-) animals, amplified IL-33 succeeded the heightened IL-4 response and inhibition of IL-4 signaling decreased IL-33. Moreover, macrophages, but not epithelial cells or dendritic cells, from these mice expressed higher IL-33 in comparison with controls. Dissection of mechanisms that promulgated IL-33 revealed type-II cytokines and H. capsulatum synergistically elicited an IL-33 response in macrophages via signal transducer and activator of transcription factor 6/interferon-regulatory factor-4 and Dectin-1 pathways, respectively. Neutralizing IL-33 in CCR2(-/-) animals, but not controls, enhanced their resistance to histoplasmosis. Thus we describe a previously unrecognized role for IL-4 in instigating IL-33 in macrophages. Furthermore, in the presence of intracellular fungal pathogens, the type-II cytokine-driven IL-33 response impairs immunity. PMID:25118166

  13. P2X7 Receptor Regulates Internalization of Antimicrobial Peptide LL-37 by Human Macrophages That Promotes Intracellular Pathogen Clearance

    PubMed Central

    Tang, Xiao; Basavarajappa, Devaraj

    2015-01-01

    Bioactive peptide LL-37/hCAP18, the only human member of the cathelicidin family, plays important roles in killing various pathogens, as well as in immune modulation. We demonstrate that LL-37 is internalized by human macrophages in a time-, dose-, temperature-, and peptide sequence–dependent endocytotic process. Both clathrin- and caveolae/lipid raft–mediated endocytosis pathways are involved in LL-37 internalization. We find that the P2X7 receptor (P2X7R) plays an important role in LL-37 internalization by human macrophages because significantly less internalized LL-37 was detected in macrophages pretreated with P2X7R antagonists or, more specifically, in differentiated THP-1 cells in which the P2X7R gene had been silenced. Furthermore, this P2X7R-mediated LL-37 internalization is primarily connected to the clathrin-mediated endocytosis pathway. In addition, our results demonstrate that internalized LL-37 traffics to endosomes and lysosomes and contributes to intracellular clearance of bacteria by human macrophages, coinciding with increased reactive oxygen species and lysosome formation. Finally, we show that human macrophages have the potential to import LL-37 released from activated human neutrophils. In conclusion, our study unveils a novel mechanism by which human macrophages internalize antimicrobial peptides to improve their intracellular pathogen clearance. PMID:26116509

  14. Structure of the virulence-associated protein VapD from the intracellular pathogen Rhodococcus equi

    SciTech Connect

    Whittingham, Jean L.; Blagova, Elena V. [University of York, Heslington, York YO10 5DD (United Kingdom); Finn, Ciaran E.; Luo, Haixia; Miranda-CasoLuengo, Raúl [University College Dublin, Dublin (Ireland); Turkenburg, Johan P.; Leech, Andrew P.; Walton, Paul H. [University of York, Heslington, York YO10 5DD (United Kingdom); Murzin, Alexey G. [MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH (United Kingdom); Meijer, Wim G. [University College Dublin, Dublin (Ireland); Wilkinson, Anthony J., E-mail: tony.wilkinson@york.ac.uk [University of York, Heslington, York YO10 5DD (United Kingdom)

    2014-08-01

    VapD is one of a set of highly homologous virulence-associated proteins from the multi-host pathogen Rhodococcus equi. The crystal structure reveals an eight-stranded ?-barrel with a novel fold and a glycine rich ‘bald’ surface. Rhodococcus equi is a multi-host pathogen that infects a range of animals as well as immune-compromised humans. Equine and porcine isolates harbour a virulence plasmid encoding a homologous family of virulence-associated proteins associated with the capacity of R. equi to divert the normal processes of endosomal maturation, enabling bacterial survival and proliferation in alveolar macrophages. To provide a basis for probing the function of the Vap proteins in virulence, the crystal structure of VapD was determined. VapD is a monomer as determined by multi-angle laser light scattering. The structure reveals an elliptical, compact eight-stranded ?-barrel with a novel strand topology and pseudo-twofold symmetry, suggesting evolution from an ancestral dimer. Surface-associated octyl-?-d-glucoside molecules may provide clues to function. Circular-dichroism spectroscopic analysis suggests that the ?-barrel structure is preceded by a natively disordered region at the N-terminus. Sequence comparisons indicate that the core folds of the other plasmid-encoded virulence-associated proteins from R. equi strains are similar to that of VapD. It is further shown that sequences encoding putative R. equi Vap-like proteins occur in diverse bacterial species. Finally, the functional implications of the structure are discussed in the light of the unique structural features of VapD and its partial structural similarity to other ?-barrel proteins.

  15. Structural asymmetry in a conserved signaling system that regulates division, replication, and virulence of an intracellular pathogen.

    PubMed

    Willett, Jonathan W; Herrou, Julien; Briegel, Ariane; Rotskoff, Grant; Crosson, Sean

    2015-07-14

    We have functionally and structurally defined an essential protein phosphorelay that regulates expression of genes required for growth, division, and intracellular survival of the global zoonotic pathogen Brucella abortus. Our study delineates phosphoryl transfer through this molecular pathway, which initiates from the sensor kinase CckA and proceeds through the ChpT phosphotransferase to two regulatory substrates: CtrA and CpdR. Genetic perturbation of this system results in defects in cell growth and division site selection, and a specific viability deficit inside human phagocytic cells. Thus, proper control of B. abortus division site polarity is necessary for survival in the intracellular niche. We further define the structural foundations of signaling from the central phosphotransferase, ChpT, to its response regulator substrate, CtrA, and provide evidence that there are at least two modes of interaction between ChpT and CtrA, only one of which is competent to catalyze phosphoryltransfer. The structure and dynamics of the active site on each side of the ChpT homodimer are distinct, supporting a model in which quaternary structure of the 2:2 ChpT-CtrA complex enforces an asymmetric mechanism of phosphoryl transfer between ChpT and CtrA. Our study provides mechanistic understanding, from the cellular to the atomic scale, of a conserved transcriptional regulatory system that controls the cellular and infection biology of B. abortus. More generally, our results provide insight into the structural basis of two-component signal transduction, which is broadly conserved in bacteria, plants, and fungi. PMID:26124143

  16. Structure of the virulence-associated protein VapD from the intracellular pathogen Rhodococcus equi.

    PubMed

    Whittingham, Jean L; Blagova, Elena V; Finn, Ciaran E; Luo, Haixia; Miranda-CasoLuengo, Raúl; Turkenburg, Johan P; Leech, Andrew P; Walton, Paul H; Murzin, Alexey G; Meijer, Wim G; Wilkinson, Anthony J

    2014-08-01

    Rhodococcus equi is a multi-host pathogen that infects a range of animals as well as immune-compromised humans. Equine and porcine isolates harbour a virulence plasmid encoding a homologous family of virulence-associated proteins associated with the capacity of R. equi to divert the normal processes of endosomal maturation, enabling bacterial survival and proliferation in alveolar macrophages. To provide a basis for probing the function of the Vap proteins in virulence, the crystal structure of VapD was determined. VapD is a monomer as determined by multi-angle laser light scattering. The structure reveals an elliptical, compact eight-stranded ?-barrel with a novel strand topology and pseudo-twofold symmetry, suggesting evolution from an ancestral dimer. Surface-associated octyl-?-D-glucoside molecules may provide clues to function. Circular-dichroism spectroscopic analysis suggests that the ?-barrel structure is preceded by a natively disordered region at the N-terminus. Sequence comparisons indicate that the core folds of the other plasmid-encoded virulence-associated proteins from R. equi strains are similar to that of VapD. It is further shown that sequences encoding putative R. equi Vap-like proteins occur in diverse bacterial species. Finally, the functional implications of the structure are discussed in the light of the unique structural features of VapD and its partial structural similarity to other ?-barrel proteins. PMID:25084333

  17. Analysis of the Bovine Intracellular Enteric Pathogen Interactome Each year the beef and dairy industries lose more than $330 million because of enteric diseases that cause the death of more than

    E-print Network

    Analysis of the Bovine Intracellular Enteric Pathogen Interactome Each year the beef and dairy weight gain. Understanding how cattle respond to enteric pathogens during acute infection is crucial have developed an in vivo bovine ligated ileal loop model to study bovine response to enteric pathogens

  18. Characterization of two pathogenic mutations in cystathionine beta-synthase: different intracellular locations for wild-type and mutant proteins.

    PubMed

    Casique, L; Kabil, O; Banerjee, R; Martinez, J C; De Lucca, M

    2013-11-15

    Cystathionine ?-synthase (CBS) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the condensation of homocysteine with serine to generate cystathionine. Homocystinuria is an autosomal recessive disorder commonly caused by a deficiency of CBS activity. Here, we characterized a novel CBS mutation (c.260C>A (p.T87N)) and a previously reported variant (c.700G>A (p.D234N)) found in Venezuelan homocystinuric patients, one nonresponsive and one responsive to vitamin B6. Both mutant proteins were expressed in vitro in prokaryotic and eukaryotic cells, finding lower soluble expression in HEK-293 cells (19% T87N and 23% D234N) compared to wild-type CBS. Residual activities obtained for the mutant proteins were 3.5% T87N and 43% D234N. Gel exclusion chromatography demonstrated a tendency of the T87N mutant to aggregate while the distribution of the D234N mutant was similar to wild-type enzyme. Using immunofluorescence microscopy, an unexpected difference in intracellular localization was observed between the wild-type and mutant proteins. While the T87N mutant exhibited a punctate appearance, the wild-type protein was homogeneously distributed inside the cell. Interestingly, the D234N protein showed both distributions. This study demonstrates that the pathogenic CBS mutations generate unstable proteins that are unable (T87N) or partially unable (D234N) to assemble into a functional enzyme, implying that these mutations might be responsible for the homocystinuria phenotype. PMID:23981774

  19. The small GTPase RAB-11 directs polarized exocytosis of the intracellular pathogen N. parisii for fecal-oral transmission from C. elegans.

    PubMed

    Szumowski, Suzannah C; Botts, Michael R; Popovich, John J; Smelkinson, Margery G; Troemel, Emily R

    2014-06-01

    Pathogen exit is a key stage in the spread and propagation of infectious disease, with the fecal-oral route being a common mode of disease transmission. However, it is poorly understood which molecular pathways provide the major modes for intracellular pathogen exit and fecal-oral transmission in vivo. Here, we use the transparent nematode Caenorhabditis elegans to investigate intestinal cell exit and fecal-oral transmission by the natural intracellular pathogen Nematocida parisii, which is a recently identified species of microsporidia. We show that N. parisii exits from polarized host intestinal cells by co-opting the host vesicle trafficking system and escaping into the lumen. Using a genetic screen, we identified components of the host endocytic recycling pathway that are required for N. parisii spore exit via exocytosis. In particular, we show that the small GTPase RAB-11 localizes to apical spores, is required for spore-containing compartments to fuse with the apical plasma membrane, and is required for spore exit. In addition, we find that RAB-11-deficient animals exhibit impaired contagiousness, supporting an in vivo role for this host trafficking factor in microsporidia disease transmission. Altogether, these findings provide an in vivo example of the major mode of exit used by a natural pathogen for disease spread via fecal-oral transmission. PMID:24843160

  20. Complete genome sequence of the Q-fever pathogen Coxiella burnetii

    Microsoft Academic Search

    Rekha Seshadri; Ian T. Paulsen; Timothy D. Read; Karen E. Nelson; William C. Nelson; Naomi L. Ward; Hervé Tettelin; Tanja M. Davidsen; Maureen J. Beanan; Robert T. Deboy; Sean C. Daugherty; Lauren M. Brinkac; Ramana Madupu; Robert J. Dodson; Hoda M. Khouri; Kathy H. Lee; Heather A. Carty; David Scanlan; Robert A. Heinzen; Herbert A. Thompson; James E. Samuel; Claire M. Fraser; John F. Heidelberg

    2003-01-01

    The 1,995,275-bp genome of Coxiella burnetii, Nine Mile phase I RSA493, a highly virulent zoonotic pathogen and category B bioterrorism agent, was sequenced by the random shotgun method. This bacterium is an obligate intracellular acidophile that is highly adapted for life within the eukaryotic phagolysosome. Genome analysis revealed many genes with potential roles in adhesion, invasion, intracellular trafficking, host-cell modulation,

  1. Intracellular eukaryotic pathogens in brown macroalgae in the Eastern Mediterranean, including LSU rRNA data for the oomycete Eurychasma dicksonii .

    PubMed

    Strittmatter, Martina; Gachon, Claire M M; Müller, Dieter G; Kleinteich, Julia; Heesch, Svenja; Tsirigoti, Amerssa; Katsaros, Christos; Kostopoulou, Maria; Küpper, Frithjof C

    2013-04-29

    For the Mediterranean Sea, and indeed most of the world's oceans, the biodiversity and biogeography of eukaryotic pathogens infecting marine macroalgae remains poorly known, yet their ecological impact is probably significant. Based on 2 sampling campaigns on the Greek island of Lesvos in 2009 and 1 in northern Greece in 2012, this study provides first records of 3 intracellular eukaryotic pathogens infecting filamentous brown algae at these locations: Eurychasma dicksonii, Anisolpidium sphacellarum, and A. ectocarpii. Field and microscopic observations of the 3 pathogens are complemented by the first E. dicksonii large subunit ribosomal RNA (LSU rRNA) gene sequence analyses of isolates from Lesvos and other parts of the world. The latter highlights the monophyly of E. dicksonii worldwide and confirms the basal position of this pathogen within the oomycete lineage (Peronosporomycotina). The results of this study strongly support the notion that the geographic distribution of the relatively few eukaryotic seaweed pathogens is probably much larger than previously thought and that many of the world's marine bioregions remain seriously undersampled and understudied in this respect. PMID:23670075

  2. Tropism and Pathogenicity of Rickettsiae

    PubMed Central

    Uchiyama, Tsuneo

    2012-01-01

    Rickettsiae are obligate intracellular parasitic bacteria that cause febrile exanthematous illnesses such as Rocky Mountain spotted fever, Mediterranean spotted fever, epidemic, and murine typhus, etc. Although the vector ranges of each Rickettsia species are rather restricted; i.e., ticks belonging to Arachnida and lice and fleas belonging to Insecta usually act as vectors for spotted fever group (SFG) and typhus group (TG) rickettsiae, respectively, it would be interesting to elucidate the mechanisms controlling the vector tropism of rickettsiae. This review discusses the factors determining the vector tropism of rickettsiae. In brief, the vector tropism of rickettsiae species is basically consistent with their tropism toward cultured tick and insect cells. The mechanisms responsible for rickettsiae pathogenicity are also described. Recently, genomic analyses of rickettsiae have revealed that they possess several genes that are homologous to those affecting the pathogenicity of other bacteria. Analyses comparing the genomes of pathogenic and non-pathogenic strains of rickettsiae have detected many factors that are related to rickettsial pathogenicity. It is also known that a reduction in the rickettsial genome has occurred during the course of its evolution. Interestingly, Rickettsia species with small genomes, such as Rickettsia prowazekii, are more pathogenic to humans than those with larger genomes. This review also examines the growth kinetics of pathogenic and non-pathogenic species of SFG rickettsiae (SFGR) in mammalian cells. The growth of non-pathogenic species is restricted in these cells, which is mediated, at least in part, by autophagy. The superinfection of non-pathogenic rickettsiae-infected cells with pathogenic rickettsiae results in an elevated yield of the non-pathogenic rickettsiae and the growth of the pathogenic rickettsiae. Autophagy is restricted in these cells. These results are discussed in this review. PMID:22737150

  3. Mimicry of the pathogenic mycobacterium vacuole in vitro elicits the bacterial intracellular phenotype, including early-onset macrophage death.

    PubMed

    Early, Julie; Bermudez, Luiz E

    2011-06-01

    Mycobacterium avium complex (MAC) within macrophages undergoes a phenotype change that allows for more efficient entry into surrounding host cells. We hypothesized that, by developing an in vitro system resembling the intravacuolar environment, one could generate insights into the mycobacterial intracellular phenotype. MAC was incubated in "elemental mixtures" that reproduce metal concentrations and pH in the vacuoles at different time points and then used to infect fresh macrophages. Incubation of MAC with the mixture corresponding to the vacuole environment 24 h postinfection infected macrophages at a significantly higher rate than bacteria that were incubated in Middlebrook 7H9 broth. Uptake occurred by macropinocytosis, similar to the uptake of bacteria passed through macrophages. Genes reported to be upregulated in intracellular bacteria, such as Mav1365, Mav2409, Mav4487, and Mav0996, were upregulated in MAC incubated in the 24-h elemental mixture. Like MAC obtained from macrophages, the vacuoles of bacteria from the 24-h elemental mixture were more likely to contain lysosome-associated membrane protein 1 (LAMP-1). A stepwise reduction scheme of the 24-h elemental mixture indicated that incubation in physiologically relevant concentrations of potassium chloride, calcium chloride, and manganese chloride was sufficient to induce characteristics of the intracellular phenotype. It was demonstrated that bacteria harboring the intracellular phenotype induced early-onset macrophage death more efficiently than bacteria grown in broth. This new trace elemental mixture mimicking the condition of the vacuole at different time points has the potential to become an effective laboratory tool for the study of the MAC and Mycobacterium tuberculosis disease process, increasing the understanding of the interaction with macrophages. PMID:21444666

  4. “Candidatus Hepatobacter penaei,” an Intracellular Pathogenic Enteric Bacterium in the Hepatopancreas of the Marine Shrimp Penaeus vannamei (Crustacea: Decapoda)

    PubMed Central

    Pantoja, Carlos R.; Gomez-Jimenez, Silvia; Lightner, Donald V.

    2013-01-01

    The bacteria that cause necrotizing hepatopancreatitis in Penaeus vannamei adversely affect penaeid shrimp cultured in the western hemisphere. 16S rRNA and gyrase B gene analyses determined the taxonomic position of these bacteria. The name “Candidatus Hepatobacter penaei” is proposed for these pathogenic bacteria, which are members of the Rickettsiales order. PMID:23241970

  5. A resealed-cell system for analyzing pathogenic intracellular events: perturbation of endocytic pathways under diabetic conditions.

    PubMed

    Kano, Fumi; Nakatsu, Daiki; Noguchi, Yoshiyuki; Yamamoto, Akitsugu; Murata, Masayuki

    2012-01-01

    Cell-based assay systems that can serve as cellular models of aberrant function in pathogenic organs would be novel and useful tools for screening drugs and clarifying the molecular mechanisms of various diseases. We constructed model cells that replicated the conditions in diabetic hepatocytes by using the cell resealing technique, which enables the exchange of cytosol. The plasma membrane of HeLa cells was permeabilized with the streptococcal toxin streptolysin O, and cytosol that had been prepared from wild-type or db/db diabetic mice was introduced into the resulting semi-intact cells. By resealing the plasma membrane by exposure to Ca(2+), we created WT or Db model cells, in which the cytosolic conditions replicated those of healthy or diabetic liver. Interestingly, phosphorylation of p38 MAPK was promoted, whereas the level of endosomal phosphatidylinositol-3-phosphate was decreased, in Db cells. We investigated several endocytic pathways in WT and Db cells, and found that retrograde endosome-to-Golgi transport was delayed in a p38 MAPK-dependent manner in Db cells. Furthermore, the degradation pathway of the EGF receptor from endosomes to lysosomes was enhanced in Db cells, and this did not depend on the activation of p38 MAPK. The disease model cell system should become a powerful tool for the detection of aberrant processes in cells under pathogenic conditions and for therapeutic applications. PMID:22952896

  6. Safety and immunogenicity of a live-attenuated auxotrophic candidate vaccine against the intracellular pathogen Rhodococcus equi.

    PubMed

    Lopez, A M; Townsend, H G G; Allen, A L; Hondalus, M K

    2008-02-13

    Rhodococcus equi causes serious pneumonia in neonatal foals and is an opportunistic pathogen of people with compromised cellular immunity. No effective vaccine against R. equi disease in foals is available. We tested the safety and immunogenicity of a live, fully attenuated riboflavin auxotrophic candidate vaccine strain of R. equi (R. equi rib-). We demonstrated that R. equi rib- is immunogenic and capable of inducing IFN-gamma responses in immunocompetent BALB/c mice, yet it is safe even in an immunocompromised SCID mouse infection model. Moreover, it protects immunocompetent mice against virulent R. equi challenge. In foals, R. equi rib- was likewise safe and stimulated serum R. equi-specific immune responses. A preliminary immunization strategy did not afford protection against virulent R. equi challenge and therefore, optimization of the vaccine formulation and or vaccination protocol will be necessary. PMID:18055071

  7. Signatures of Adaptation to Obligate Biotrophy in the Hyaloperonospora arabidopsidis Genome

    Microsoft Academic Search

    Laura Baxter; Sucheta Tripathy; Naveed Ishaque; Nico Boot; Adriana Cabral; Eric Kemen; Marco Thines; Audrey Ah-Fong; Ryan Anderson; Wole Badejoko; Peter Bittner-Eddy; Jeffrey L. Boore; Marcus C. Chibucos; Mary Coates; Paramvir Dehal; Kim Delehaunty; Suomeng Dong; Polly Downton; Bernard Dumas; Georgina Fabro; Catrina Fronick; Susan I. Fuerstenberg; Lucinda Fulton; Elodie Gaulin; Francine Govers; Linda Hughes; Sean Humphray; Rays H. Y. Jiang; Howard Judelson; Sophien Kamoun; Kim Kyung; Harold Meijer; Patrick Minx; Paul Morris; Joanne Nelson; Vipa Phuntumart; Dinah Qutob; Anne Rehmany; Alejandra Rougon-Cardoso; Peter Ryden; Trudy Torto-Alalibo; David Studholme; Yuanchao Wang; Joe Win; Jo Wood; Sandra W. Clifton; Jane Rogers; Guido Van den Ackerveken; Jonathan D. G. Jones; John M. McDowell; Jim Beynon; Brett M. Tyler

    2010-01-01

    Many oomycete and fungal plant pathogens are obligate biotrophs, which extract nutrients only from living plant tissue and cannot grow apart from their hosts. Although these pathogens cause substantial crop losses, little is known about the molecular basis or evolution of obligate biotrophy. Here, we report the genome sequence of the oomycete Hyaloperonospora arabidopsidis (Hpa), an obligate biotroph and natural

  8. Depletion of autophagy-related genes ATG3 and ATG5 in Tenebrio molitor leads to decreased survivability against an intracellular pathogen, Listeria monocytogenes.

    PubMed

    Tindwa, Hamisi; Jo, Yong Hun; Patnaik, Bharat Bhusan; Noh, Mi Young; Kim, Dong Hyun; Kim, Iksoo; Han, Yeon Soo; Lee, Yong Seok; Lee, Bok Luel; Kim, Nam Jung

    2015-01-01

    Macroautophagy (autophagy) is an evolutionarily conserved catabolic process involved in physiological and developmental processes including cell survival, death, and innate immunity. Homologues of most of 36 originally discovered autophagy-related (ATG) genes in yeast have been characterized in higher eukaryotes including insects. In this study, the homologues of ATG3 (TmATG3) and ATG5 (TmATG5) were isolated from the coleopteran beetle, Tenebrio molitor by expressed sequence tag and RNAseq approaches. The cDNA of TmATG3 and TmATG5 comprise open-reading frame sizes of 963 and 792 bp encoding polypeptides of 320 and 263 amino acid residues, respectively. TmATG3 and TmATG5 mRNA are expressed in all developmental stages, and mainly in fat body and hemocytes of larvae. TmATG3 and TmATG5 showed an overall sequence identity of 58-95% to other insect Atg proteins. There exist clear one-to-one orthologs of TmATG3 and TmATG5 in Tribolium and that they clustered together in the gene tree. Depletion of TmATG3 and TmATG5 by RNA interference led to a significant reduction in survival ability of T. molitor larvae against an intracellular pathogen, Listeria monocytogenes. Six days post-Listeria challenge, the survival rate in the dsEGFP-injected (where EGFP is enhanced green fluorescent protein) control larvae was significantly higher (55%) compared to 4 and 3% for TmATG3 and TmATG5 double-stranded RNA injected larvae, respectively. These data suggested that TmATG3 and TmATG5 may play putative role in mediating autophagy-based clearance of Listeria in T. molitor model. PMID:25403020

  9. Contrasting host-pathogen interactions and genome evolution in two generalist and specialist microsporidian pathogens of mosquitoes.

    PubMed

    Desjardins, Christopher A; Sanscrainte, Neil D; Goldberg, Jonathan M; Heiman, David; Young, Sarah; Zeng, Qiandong; Madhani, Hiten D; Becnel, James J; Cuomo, Christina A

    2015-01-01

    Obligate intracellular pathogens depend on their host for growth yet must also evade detection by host defenses. Here we investigate host adaptation in two Microsporidia, the specialist Edhazardia aedis and the generalist Vavraia culicis, pathogens of disease vector mosquitoes. Genomic analysis and deep RNA-Seq across infection time courses reveal fundamental differences between these pathogens. E. aedis retains enhanced cell surface modification and signalling capacity, upregulating protein trafficking and secretion dynamically during infection. V. culicis is less dependent on its host for basic metabolites and retains a subset of spliceosomal components, with a transcriptome broadly focused on growth and replication. Transcriptional profiling of mosquito immune responses reveals that response to infection by E. aedis differs dramatically depending on the mode of infection, and that antimicrobial defensins may play a general role in mosquito defense against Microsporidia. This analysis illuminates fundamentally different evolutionary paths and host interplay of specialist and generalist pathogens. PMID:25968466

  10. Contrasting host–pathogen interactions and genome evolution in two generalist and specialist microsporidian pathogens of mosquitoes

    PubMed Central

    Desjardins, Christopher A.; Sanscrainte, Neil D.; Goldberg, Jonathan M.; Heiman, David; Young, Sarah; Zeng, Qiandong; Madhani, Hiten D.; Becnel, James J.; Cuomo, Christina A

    2015-01-01

    Obligate intracellular pathogens depend on their host for growth yet must also evade detection by host defenses. Here we investigate host adaptation in two Microsporidia, the specialist Edhazardia aedis and the generalist Vavraia culicis, pathogens of disease vector mosquitoes. Genomic analysis and deep RNA-Seq across infection time courses reveal fundamental differences between these pathogens. E. aedis retains enhanced cell surface modification and signalling capacity, upregulating protein trafficking and secretion dynamically during infection. V. culicis is less dependent on its host for basic metabolites and retains a subset of spliceosomal components, with a transcriptome broadly focused on growth and replication. Transcriptional profiling of mosquito immune responses reveals that response to infection by E. aedis differs dramatically depending on the mode of infection, and that antimicrobial defensins may play a general role in mosquito defense against Microsporidia. This analysis illuminates fundamentally different evolutionary paths and host interplay of specialist and generalist pathogens. PMID:25968466

  11. Intracellular Parasite Invasion Strategies

    NASA Astrophysics Data System (ADS)

    Sibley, L. D.

    2004-04-01

    Intracellular parasites use various strategies to invade cells and to subvert cellular signaling pathways and, thus, to gain a foothold against host defenses. Efficient cell entry, ability to exploit intracellular niches, and persistence make these parasites treacherous pathogens. Most intracellular parasites gain entry via host-mediated processes, but apicomplexans use a system of adhesion-based motility called ``gliding'' to actively penetrate host cells. Actin polymerization-dependent motility facilitates parasite migration across cellular barriers, enables dissemination within tissues, and powers invasion of host cells. Efficient invasion has brought widespread success to this group, which includes Toxoplasma, Plasmodium, and Cryptosporidium.

  12. Washing and Disinfecting Fish Gills: Preventing Contamination by Normal Surface Microflora of Cell Cultures Inoculated with Tissue for Isolating Intracellular Pathogens

    Microsoft Academic Search

    Agnar Kvellestad; Laila G. Aune; Birgit H. Dannevig

    2002-01-01

    Contamination of cell cultures by the normal microflora of water, to which fish gills are exposed, is a major obstacle to in vitro culture of the pathogenic and presumptively antibiotic-sensitive rickettsia- and chlamydia-like organisms infecting gill epithelial cells. Therefore, a protocol was developed for removal or inactivation of these potential contaminating organisms. Gills of Atlantic salmon Salmo salar were vigorously

  13. Killing of Mycobacterium avium and Mycobacterium tuberculosis by a Mycobacteriophage Delivered by a Nonvirulent Mycobacterium: A Model for Phage Therapy of Intracellular Bacterial Pathogens

    Microsoft Academic Search

    Lawrence Broxmeyer; Danuta Sosnowska; Elizabeth Miltner; Ofelia Chacón; Dirk Wagner; Jeffery McGarvey

    2002-01-01

    Mycobacterium avium causes disseminated infection in patients with acquired immune de- ficieny syndrome. Mycobacterium tuberculosis is a pathogen associated with the deaths of millions of people worldwide annually. Effective therapeutic regimens exist that are limited by the emergence of drug resistance and the inability of antibiotics to kill dormant organisms. The present study describes a system using Mycobacterium smegmatis, an

  14. Identification of pathogenic mechanisms of COCH mutations, abolished cochlin secretion, and intracellular aggregate formation: genotype-phenotype correlations in DFNA9 deafness and vestibular disorder.

    PubMed

    Bae, Seung-Hyun; Robertson, Nahid G; Cho, Hyun-Ju; Morton, Cynthia C; Jung, Da Jung; Baek, Jeong-In; Choi, Soo-Young; Lee, Jaetae; Lee, Kyu-Yup; Kim, Un-Kyung

    2014-12-01

    Mutations in COCH (coagulation factor C homology) cause autosomal-dominant nonsyndromic hearing loss with variable degrees of clinical onset and vestibular malfunction. We selected eight uncharacterized mutations and performed immunocytochemical and Western blot analyses to track cochlin through the secretory pathway. We then performed a comprehensive analysis of clinical information from DFNA9 patients with all 21 known COCH mutations in conjunction with cellular and molecular findings to identify genotype-phenotype correlations. Our studies revealed that five mutants were not secreted into the media: two von Willebrand factor A (vWFA) domain mutants, which were not transported from the endoplasmic reticulum to Golgi complex and formed high-molecular-weight aggregates in cell lysates, and three LCCL domain mutants, which were detected as intracellular dimeric cochlins. Mutant cochlins that were not secreted and accumulated in cells result in earlier age of onset of hearing defects. In addition, individuals with LCCL domain mutations show accompanying vestibular dysfunction, whereas those with vWFA domain mutations exhibit predominantly hearing loss. This is the first report showing failure of mutant cochlin transport through the secretory pathway, abolishment of cochlin secretion, and formation and retention of dimers and large multimeric intracellular aggregates, and high correlation with earlier onset and progression of hearing loss in individuals with these DFNA9-causing mutations. PMID:25230692

  15. Intracellular proteoglycans.

    PubMed Central

    Kolset, Svein Olav; Prydz, Kristian; Pejler, Gunnar

    2004-01-01

    Proteoglycans (PGs) are proteins with glycosaminoglycan chains, are ubiquitously expressed and have a wide range of functions. PGs in the extracellular matrix and on the cell surface have been the subject of extensive structural and functional studies. Less attention has so far been given to PGs located in intracellular compartments, although several reports suggest that these have biological functions in storage granules, the nucleus and other intracellular organelles. The purpose of this review is, therefore, to present some of these studies and to discuss possible functions linked to PGs located in different intracellular compartments. Reference will be made to publications relevant for the topics we present. It is beyond the scope of this review to cover all publications on PGs in intracellular locations. PMID:14759226

  16. Increased intracellular calcium level and impaired nutrient absorption are important pathogenicity traits in the chicken intestinal epithelium during Campylobacter jejuni colonization.

    PubMed

    Awad, Wageha A; Smorodchenko, Alina; Hess, Claudia; Aschenbach, Jörg R; Molnár, Andor; Dublecz, Károly; Khayal, Basel; Pohl, Elena E; Hess, Michael

    2015-08-01

    Although a high number of chickens carry Campylobacter jejuni, the mechanistic action of colonization in the intestine is still poorly understood. The current study was therefore designed to investigate the effects of C. jejuni on glucose uptake, amino acids availability in digesta, and intracellular calcium [Ca(2+)]i signaling in the intestines of broiler chickens. For this, we compared: control birds (n?=?60) and C. jejuni-infected birds (n?=?60; infected orally with 1?×?10(8) CFU of C. jejuni NCTC 12744 at 14 days of age). Our results showed that glucose uptake was reduced due to C. jejuni infection in isolated jejunal, but not in cecal mucosa at 14 days postinfection (dpi). The decrease in intestinal glucose absorption coincided with a decrease in body weight gain during the 2-week post-infectious period. A reduction in the amount of the amino acids (serine, proline, valine, leucine, phenylalanine, arginine, histidine, and lysine) in ileal digesta of the infected birds at 2 and/or 7 dpi was found, indicating that Campylobacter utilizes amino acids as a carbon source for their multiplication. Applying the cell-permeable Ca(2+) indicator Fluo-4 and two-photon microscopy, we revealed that [Ca(2+)]i was increased in the jejunal and cecal mucosa of infected birds. The muscarinic agonist carbachol induced an increase in [Ca(2+)]i in jejunum and cecum mucosa of control chickens, a response absent in the mucosa of infected chickens, demonstrating that the modulation of [Ca(2+)]i by Campylobacter might be involved in facilitating the necessary cytoskeletal rearrangements that occur during the bacterial invasion of epithelial cells. In conclusion, this study demonstrates the multifaceted interactions of C. jejuni with the gastrointestinal mucosa of broiler chickens. For the first time, it could be shown that a Campylobacter infection could interfere with intracellular Ca(2+) signaling and nutrient absorption in the small intestine with consequences on intestinal function, performance, and Campylobacter colonization. Altogether, these findings indicate that Campylobacter is not entirely a commensal and can be recognized as an important factor contributing to an impaired chicken gut health. PMID:25825050

  17. Functional genomics of intracellular bacteria.

    PubMed

    de Barsy, Marie; Greub, Gilbert

    2013-07-01

    During the genomic era, a large amount of whole-genome sequences accumulated, which identified many hypothetical proteins of unknown function. Rapidly, functional genomics, which is the research domain that assign a function to a given gene product, has thus been developed. Functional genomics of intracellular pathogenic bacteria exhibit specific peculiarities due to the fastidious growth of most of these intracellular micro-organisms, due to the close interaction with the host cell, due to the risk of contamination of experiments with host cell proteins and, for some strict intracellular bacteria such as Chlamydia, due to the absence of simple genetic system to manipulate the bacterial genome. To identify virulence factors of intracellular pathogenic bacteria, functional genomics often rely on bioinformatic analyses compared with model organisms such as Escherichia coli and Bacillus subtilis. The use of heterologous expression is another common approach. Given the intracellular lifestyle and the many effectors that are used by the intracellular bacteria to corrupt host cell functions, functional genomics is also often targeting the identification of new effectors such as those of the T4SS of Brucella and Legionella. PMID:23564838

  18. Intracellular Locations of Replication Proteins and the Origin of Replication during Chromosome Duplication in the Slowly Growing Human Pathogen Helicobacter pylori

    PubMed Central

    Sharma, Atul; Kamran, Mohammad; Verma, Vijay

    2014-01-01

    We followed the position of the replication complex in the pathogenic bacterium Helicobacter pylori using antibodies raised against the single-stranded DNA binding protein (HpSSB) and the replicative helicase (HpDnaB). The position of the replication origin, oriC, was also localized in growing cells by fluorescence in situ hybridization (FISH) with fluorescence-labeled DNA sequences adjacent to the origin. The replisome assembled at oriC near one of the cell poles, and the two forks moved together toward the cell center as replication progressed in the growing cell. Termination and resolution of the forks occurred near midcell, on one side of the septal membrane. The duplicated copies of oriC did not separate until late in elongation, when the daughter chromosomes segregated into bilobed nucleoids, suggesting sister chromatid cohesion at or near the oriC region. Components of the replication machinery, viz., HpDnaB and HpDnaG (DNA primase), were found associated with the cell membrane. A model for the assembly and location of the H. pylori replication machinery during chromosomal duplication is presented. PMID:24363345

  19. Signatures of adaptation to obligate biotrophy in the Hyaloperonospora arabidopsidis genome

    PubMed Central

    Ishaque, Naveed; Boot, Nico; Cabral, Adriana; Kemen, Eric; Thines, Marco; Ah-Fong, Audrey; Anderson, Ryan; Badejoko, Wole; Bittner-Eddy, Peter; Boore, Jeffrey L.; Chibucos, Marcus C.; Coates, Mary; Dehal, Paramvir; Delehaunty, Kim; Dong, Suomeng; Downton, Polly; Dumas, Bernard; Fabro, Georgina; Fronick, Catrina; Fuerstenberg, Susan I.; Fulton, Lucinda; Gaulin, Elodie; Govers, Francine; Hughes, Linda; Humphray, Sean; Jiang, Rays H. Y.; Judelson, Howard; Kamoun, Sophien; Kyung, Kim; Meijer, Harold; Minx, Patrick; Morris, Paul; Nelson, Joanne; Phuntumart, Vipa; Qutob, Dinah; Rehmany, Anne; Rougon-Cardoso, Alejandra; Ryden, Peter; Torto-Alalibo, Trudy; Studholme, David; Wang, Yuanchao; Win, Joe; Wood, Jo; Clifton, Sandra W.; Rogers, Jane; Van den Ackerveken, Guido; Jones, Jonathan D. G.; McDowell, John M.; Beynon, Jim; Tyler, Brett M.

    2014-01-01

    Many oomycete and fungal plant pathogens are obligate biotrophs, which extract nutrients only from living plant tissue and cannot grow apart from their hosts. Although these pathogens cause significant crop losses, little is known about the molecular basis or evolution of obligate biotrophy. Here, we report the genome sequence of the oomycete Hyaloperonospora arabidopsidis (Hpa), an obligate biotroph and natural pathogen of Arabidopsis thaliana. In comparison to genomes of related, hemi-biotrophic Phytophthora species, the Hpa genome exhibits dramatic reductions in genes encoding: 1) RXLR effectors and other secreted pathogenicity proteins; 2) enzymes for assimilation of inorganic nitrogen and sulphur; 3) proteins associated with zoospore formation and motility. These attributes comprise a genomic signature of evolution towards obligate biotrophy. PMID:21148394

  20. Genomic organization, sequence characterization and expression analysis of Tenebrio molitor apolipophorin-III in response to an intracellular pathogen, Listeria monocytogenes.

    PubMed

    Noh, Ju Young; Patnaik, Bharat Bhusan; Tindwa, Hamisi; Seo, Gi Won; Kim, Dong Hyun; Patnaik, Hongray Howrelia; Jo, Yong Hun; Lee, Yong Seok; Lee, Bok Luel; Kim, Nam Jung; Han, Yeon Soo

    2014-01-25

    Apolipophorin III (apoLp-III) is a well-known hemolymph protein having a functional role in lipid transport and immune response of insects. We cloned full-length cDNA encoding putative apoLp-III from larvae of the coleopteran beetle, Tenebrio molitor (TmapoLp-III), by identification of clones corresponding to the partial sequence of TmapoLp-III, subsequently followed with full length sequencing by a clone-by-clone primer walking method. The complete cDNA consists of 890 nucleotides, including an ORF encoding 196 amino acid residues. Excluding a putative signal peptide of the first 20 amino acid residues, the 176-residue mature apoLp-III has a calculated molecular mass of 19,146Da. Genomic sequence analysis with respect to its cDNA showed that TmapoLp-III was organized into four exons interrupted by three introns. Several immune-related transcription factor binding sites were discovered in the putative 5'-flanking region. BLAST and phylogenetic analyses reveal that TmapoLp-III has high sequence identity (88%) with Tribolium castaneum apoLp-III but shares little sequence homologies (<26%) with other apoLp-IIIs. Homology modeling of Tm apoLp-III shows a bundle of five amphipathic alpha helices, including a short helix 3'. The 'helix-short helix-helix' motif was predicted to be implicated in lipid binding interactions, through reversible conformational changes and accommodating the hydrophobic residues to the exterior for stability. Highest level of TmapoLp-III mRNA was detected at late pupal stages, albeit it is expressed in the larval and adult stages at lower levels. The tissue specific expression of the transcripts showed significantly higher numbers in larval fat body and adult integument. In addition, TmapoLp-III mRNA was found to be highly upregulated in late stages of L. monocytogenes or E. coli challenge. These results indicate that TmapoLp-III may play an important role in innate immune responses against bacterial pathogens in T. molitor. PMID:24200961

  1. Comparison of the 'Ca Liberibacter asiaticus' genome adapted for an intracellular lifestyle with other members of the rhizobiales

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An intracellular plant pathogen ‘Ca. Liberibacter asiaticus,’ a member of the Rhizobiales, is related to Sinorhizobium meliloti, Bradyrhizobium japonicum, Agrobacterium tumefaciens and Bartonella henselae, an intracellular mammalian pathogen. Whole chromosome comparisons identified at least 52 clust...

  2. The genome of the obligate endobacterium of an AM fungus reveals an interphylum network of nutritional interactions

    PubMed Central

    Ghignone, Stefano; Salvioli, Alessandra; Anca, Iulia; Lumini, Erica; Ortu, Giuseppe; Petiti, Luca; Cruveiller, Stéphane; Bianciotto, Valeria; Piffanelli, Pietro; Lanfranco, Luisa; Bonfante, Paola

    2012-01-01

    As obligate symbionts of most land plants, arbuscular mycorrhizal fungi (AMF) have a crucial role in ecosystems, but to date, in the absence of genomic data, their adaptive biology remains elusive. In addition, endobacteria are found in their cytoplasm, the role of which is unknown. In order to investigate the function of the Gram-negative Candidatus Glomeribacter gigasporarum, an endobacterium of the AMF Gigaspora margarita, we sequenced its genome, leading to an ?1.72-Mb assembly. Phylogenetic analyses placed Ca. G. gigasporarum in the Burkholderiaceae whereas metabolic network analyses clustered it with insect endobacteria. This positioning of Ca. G. gigasporarum among different bacterial classes reveals that it has undergone convergent evolution to adapt itself to intracellular lifestyle. The genome annotation of this mycorrhizal-fungal endobacterium has revealed an unexpected genetic mosaic where typical determinants of symbiotic, pathogenic and free-living bacteria are integrated in a reduced genome. Ca. G. gigasporarum is an aerobic microbe that depends on its host for carbon, phosphorus and nitrogen supply; it also expresses type II and type III secretion systems and synthesizes vitamin B12, antibiotics- and toxin-resistance molecules, which may contribute to the fungal host's ecological fitness. Ca. G. gigasporarum has an extreme dependence on its host for nutrients and energy, whereas the fungal host is itself an obligate biotroph that relies on a photosynthetic plant. Our work represents the first step towards unraveling a complex network of interphylum interactions, which is expected to have a previously unrecognized ecological impact. PMID:21866182

  3. The Francisella Intracellular Life Cycle: Toward Molecular Mechanisms of Intracellular Survival and Proliferation

    PubMed Central

    Chong, Audrey; Celli, Jean

    2010-01-01

    The tularemia-causing bacterium Francisella tularensis is a facultative intracellular organism with a complex intracellular lifecycle that ensures its survival and proliferation in a variety of mammalian cell types, including professional phagocytes. Because this cycle is essential to Francisella pathogenesis and virulence, much research has focused on deciphering the mechanisms of its intracellular survival and replication and characterizing both bacterial and host determinants of the bacterium's intracellular cycle. Studies of various strains and host cell models have led to the consensual paradigm of Francisella as a cytosolic pathogen, but also to some controversy about its intracellular cycle. In this review, we will detail major findings that have advanced our knowledge of Francisella intracellular survival strategies and also attempt to reconcile discrepancies that exist in our molecular understanding of the Francisella–phagocyte interactions. PMID:21687806

  4. Resistance to Bacterial Pathogens in Plants

    E-print Network

    Innes, Roger

    Resistance to Bacterial Pathogens in Plants Jules Ade, Indiana University, Bloomington, Indiana, pathogens must overcome three layers of defense: (1) preformed physical barriers; (2) a cell-surface-based surveillance system that detects conserved pathogen molecules and (3) an intracellular surveillance system

  5. 12 CFR 987.10 - Obligations of United States with respect to consolidated obligations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...respect to consolidated obligations. 987.10 Section 987.10 Banks and Banking FEDERAL HOUSING FINANCE BOARD OFFICE OF FINANCE BOOK-ENTRY PROCEDURE FOR CONSOLIDATED OBLIGATIONS § 987.10 Obligations of United States with...

  6. 17 CFR 200.54 - Constitutional obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 false Constitutional obligations. 200.54...of Ethics § 200.54 Constitutional obligations. The...must faithfully execute the laws which they are charged with...against any infringement of the constitutional rights, privileges,...

  7. 34 CFR 108.5 - Compliance obligations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Education OFFICE FOR CIVIL RIGHTS, DEPARTMENT OF EDUCATION EQUAL ACCESS TO PUBLIC SCHOOL FACILITIES FOR THE BOY SCOUTS OF AMERICA AND OTHER DESIGNATED YOUTH GROUPS § 108.5 Compliance obligations. (a) The obligation of covered entities...

  8. 42 CFR 136.332 - Service obligation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Service obligation. 136.332 Section 136.332 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT...Subdivision J-4-Indian Health Scholarship Program § 136.332 Service obligation. The service...

  9. 42 CFR 136.332 - Service obligation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Service obligation. 136.332 Section 136.332 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT...Subdivision J-4-Indian Health Scholarship Program § 136.332 Service obligation. The service...

  10. 42 CFR 136.332 - Service obligation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Service obligation. 136.332 Section 136.332 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT...Subdivision J-4-Indian Health Scholarship Program § 136.332 Service obligation. The service...

  11. 42 CFR 136.332 - Service obligation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Service obligation. 136.332 Section 136.332 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT...Subdivision J-4-Indian Health Scholarship Program § 136.332 Service obligation. The service...

  12. 42 CFR 136.332 - Service obligation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Service obligation. 136.332 Section 136.332 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT...Subdivision J-4-Indian Health Scholarship Program § 136.332 Service obligation. The service...

  13. Identification of C. burnetii Type IV Secretion Substrates Required for Intracellular Replication and Coxiella-Containing Vacuole Formation 

    E-print Network

    Weber, Mary

    2014-05-05

    Coxiella burnetii is a Gram-negative intracellular pathogen that encodes a specialized type IVb secretion system (T4SS) which is essential for intracellular replication, Coxiella-containing vacuole (CCV) formation, modulation ...

  14. Hijacking of Host Cellular Functions by an Intracellular Parasite, the Microsporidian Anncaliia algerae

    PubMed Central

    Panek, Johan; El Alaoui, Hicham; Mone, Anne; Urbach, Serge; Demettre, Edith; Texier, Catherine; Brun, Christine; Zanzoni, Andreas; Peyretaillade, Eric; Parisot, Nicolas; Lerat, Emmanuelle; Peyret, Pierre; Delbac, Frederic; Biron, David G.

    2014-01-01

    Intracellular pathogens including bacteria, viruses and protozoa hijack host cell functions to access nutrients and to bypass cellular defenses and immune responses. These strategies have been acquired through selective pressure and allowed pathogens to reach an appropriate cellular niche for their survival and growth. To get new insights on how parasites hijack host cellular functions, we developed a SILAC (Stable Isotope Labeling by Amino Acids in Cell culture) quantitative proteomics workflow. Our study focused on deciphering the cross-talk in a host-parasite association, involving human foreskin fibroblasts (HFF) and the microsporidia Anncaliia algerae, a fungus related parasite with an obligate intracellular lifestyle and a strong host dependency. The host-parasite cross-talk was analyzed at five post-infection times 1, 6, 12 and 24 hours post-infection (hpi) and 8 days post-infection (dpi). A significant up-regulation of four interferon-induced proteins with tetratricopeptide repeats IFIT1, IFIT2, IFIT3 and MX1 was observed at 8 dpi suggesting a type 1 interferon (IFN) host response. Quantitative alteration of host proteins involved in biological functions such as signaling (STAT1, Ras) and reduction of the translation activity (EIF3) confirmed a host type 1 IFN response. Interestingly, the SILAC approach also allowed the detection of 148 A. algerae proteins during the kinetics of infection. Among these proteins many are involved in parasite proliferation, and an over-representation of putative secreted effectors proteins was observed. Finally our survey also suggests that A. algerae could use a transposable element as a lure strategy to escape the host innate immune system. PMID:24967735

  15. NLR functions beyond pathogen recognition

    Microsoft Academic Search

    Thomas A Kufer; Philippe J Sansonetti

    2011-01-01

    The last 10 years have witnessed the identification of a new class of intracellular pattern-recognition molecules—the nucleotide-binding domain and leucine-rich repeat–containing family (NLR). Members of this family garnered interest as pattern-recognition receptors able to trigger inflammatory responses against pathogens. Many studies support a pathogen-recognition function for human NLR proteins and shed light on their role in the broader control of

  16. Intervention of Phytohormone Pathways by Pathogen Effectors.

    PubMed

    Kazan, Kemal; Lyons, Rebecca

    2014-06-10

    The constant struggle between plants and microbes has driven the evolution of multiple defense strategies in the host as well as offense strategies in the pathogen. To defend themselves from pathogen attack, plants often rely on elaborate signaling networks regulated by phytohormones. In turn, pathogens have adopted innovative strategies to manipulate phytohormone-regulated defenses. Tactics frequently employed by plant pathogens involve hijacking, evading, or disrupting hormone signaling pathways and/or crosstalk. As reviewed here, this is achieved mechanistically via pathogen-derived molecules known as effectors, which target phytohormone receptors, transcriptional activators and repressors, and other components of phytohormone signaling in the host plant. Herbivores and sap-sucking insects employ obligate pathogens such as viruses, phytoplasma, or symbiotic bacteria to intervene with phytohormone-regulated defenses. Overall, an improved understanding of phytohormone intervention strategies employed by pests and pathogens during their interactions with plants will ultimately lead to the development of new crop protection strategies. PMID:24920334

  17. Selective amplification of Brucella melitensis mRNA from a mixed host-pathogen total RNA

    Microsoft Academic Search

    Carlos A Rossetti; Cristi L Galindo; Harold R Garner; L Garry Adams

    2010-01-01

    BACKGROUND: Brucellosis is a worldwide anthropozoonotic disease caused by an in vivo intracellular pathogen belonging to genus Brucella. The characterization of brucelae transcriptome's during host-pathogen interaction has been limited due to the difficulty of obtaining an adequate quantity of good quality eukaryotic RNA-free pathogen RNA for downstream applications. FINDINGS: Here, we describe a combined protocol to prepare RNA from intracellular

  18. Pathogenic trickery: deception of host cell processes

    Microsoft Academic Search

    Leigh A. Knodler; Jean Celli; B. Brett Finlay

    2001-01-01

    Microbial pathogens cause a spectrum of diseases in humans. Although the disease mechanisms vary considerably, most pathogens have developed virulence factors that interact with host molecules, often usurping normal cellular processes, including cytoskeletal dynamics and vesicle targeting. These virulence factors often mimic host molecules, and mediate events as diverse as bacterial invasion, antiphagocytosis, and intracellular parastism.

  19. Specific Inhibition of Obligate Anaerobes

    Microsoft Academic Search

    Herbert N. Prince

    1960-01-01

    MANY drugs are known which optimally inhibit single groups of micro-organisms (bacteria, fungi, or protozoa), or which inhibit specific types within one of these groups (Gram-positive or Gram-negative bacteria, pathogenic or non-pathogenic fungi). For example, certain antibiotics only inhibit bacteria; the polyene antibiotics only inhibit fungi; fumagillin inhibits protozoa1. This list can be extended to include compounds other than antibiotics:

  20. The Obligate Mutualist Wigglesworthia glossinidia Influences Reproduction, Digestion, and Immunity Processes of Its Host, the Tsetse Fly

    Microsoft Academic Search

    Roshan Pais; Claudia Lohs; Yineng Wu; Jingwen Wang; Serap Aksoy

    2008-01-01

    Tsetse flies (Diptera: Glossinidae) are vectors for trypanosome parasites, the agents of the deadly sleeping sickness disease in Africa. Tsetse also harbor two maternally transmitted enteric mutualist endosymbionts: the primary intracellular obligate Wigglesworthia glossinidia and the secondary commensal Sodalis glossinidius. Both endosymbionts are transmitted to the intrauterine progeny through the milk gland secretions of the viviparous female. We administered various

  1. Macrophage defense mechanisms against intracellular bacteria.

    PubMed

    Weiss, Günter; Schaible, Ulrich E

    2015-03-01

    Macrophages and neutrophils play a decisive role in host responses to intracellular bacteria including the agent of tuberculosis (TB), Mycobacterium tuberculosis as they represent the forefront of innate immune defense against bacterial invaders. At the same time, these phagocytes are also primary targets of intracellular bacteria to be abused as host cells. Their efficacy to contain and eliminate intracellular M. tuberculosis decides whether a patient initially becomes infected or not. However, when the infection becomes chronic or even latent (as in the case of TB) despite development of specific immune activation, phagocytes have also important effector functions. Macrophages have evolved a myriad of defense strategies to combat infection with intracellular bacteria such as M. tuberculosis. These include induction of toxic anti-microbial effectors such as nitric oxide and reactive oxygen intermediates, the stimulation of microbe intoxication mechanisms via acidification or metal accumulation in the phagolysosome, the restriction of the microbe's access to essential nutrients such as iron, fatty acids, or amino acids, the production of anti-microbial peptides and cytokines, along with induction of autophagy and efferocytosis to eliminate the pathogen. On the other hand, M. tuberculosis, as a prime example of a well-adapted facultative intracellular bacterium, has learned during evolution to counter-balance the host's immune defense strategies to secure survival or multiplication within this otherwise hostile environment. This review provides an overview of innate immune defense of macrophages directed against intracellular bacteria with a focus on M. tuberculosis. Gaining more insights and knowledge into this complex network of host-pathogen interaction will identify novel target sites of intervention to successfully clear infection at a time of rapidly emerging multi-resistance of M. tuberculosis against conventional antibiotics. PMID:25703560

  2. Real-Time Molecular Monitoring of Chemical Environment in ObligateAnaerobes during Oxygen Adaptive Response

    SciTech Connect

    Holman, Hoi-Ying N.; Wozei, Eleanor; Lin, Zhang; Comolli, Luis R.; Ball, David. A.; Borglin, Sharon; Fields, Matthew W.; Hazen, Terry C.; Downing, Kenneth H.

    2009-02-25

    Determining the transient chemical properties of the intracellular environment canelucidate the paths through which a biological system adapts to changes in its environment, for example, the mechanisms which enable some obligate anaerobic bacteria to survive a sudden exposure to oxygen. Here we used high-resolution Fourier Transform Infrared (FTIR) spectromicroscopy to continuously follow cellular chemistry within living obligate anaerobes by monitoring hydrogen bonding in their cellular water. We observed a sequence of wellorchestrated molecular events that correspond to changes in cellular processes in those cells that survive, but only accumulation of radicals in those that do not. We thereby can interpret the adaptive response in terms of transient intracellular chemistry and link it to oxygen stress and survival. This ability to monitor chemical changes at the molecular level can yield important insights into a wide range of adaptive responses.

  3. PAK in pathogen-host interactions.

    PubMed

    Semblat, Jean-Philippe; Doerig, Christian

    2012-04-01

    Eukaryotic, prokaryotic and viral pathogens are known to interfere with signaling pathways of their host to promote their own survival and proliferation. Here, we present selected examples of modulation of PAK activity in human cells by both intracellular and extracellular pathogens, focusing on one eukaryotic pathogen, the human malaria parasite Plasmodium falciparum, two Gram-negative bacteria (Helicobacter pylori and Pseudomonas aeruginosa), and two viruses belonging to distinct groups, the lentivirus HIV and the orthomyxovirus Influenza virus A. PMID:23125952

  4. Innate recognition of intracellular bacteria.

    PubMed

    Delbridge, Laura M; O'Riordan, Mary X D

    2007-02-01

    The molecular repertoire for innate recognition of bacterial pathogens has expanded rapidly in the past decade. These immunosensors include Toll-like receptors and the more recently defined NOD-like receptors (NLRs): NODs, NALPs, NAIP and IPAF. Toll-like receptors signal from the cell surface or endosome upon ligand binding, whereas NLRs are activated by characteristic bacterially derived molecules, such as peptidoglycan, RNA, toxins and flagellin, in the cytosol. Studies using animal and culture models of bacterial infection indicate a pro-inflammatory role for NLRs, mediated by signaling through nuclear transcription factor kappaB and activation of caspase-1 by the inflammasome. These data also support a synergistic role for extracellular and intracellular bacterial sensing in regulating inflammation. In humans, NLR mutations are often associated with autoinflammatory syndromes, suggesting a complex role for cytosolic surveillance in systemic innate immunity. PMID:17126540

  5. Twenty years of research into Chlamydia-like organisms: a revolution in our understanding of the biology and pathogenicity of members of the phylum Chlamydiae.

    PubMed

    Taylor-Brown, Alyce; Vaughan, Lloyd; Greub, Gilbert; Timms, Peter; Polkinghorne, Adam

    2015-02-01

    Chlamydiae are obligate intracellular bacteria that share a unique but remarkably conserved biphasic developmental cycle that relies on a eukaryotic host cell for survival. Although the phylum was originally thought to only contain one family, the Chlamydiaceae, a total of nine families are now recognized. These so-called Chlamydia-like organisms (CLOs) are also referred to as 'environmental chlamydiae', as many were initially isolated from environmental sources. However, these organisms are also emerging pathogens, as many, such as Parachlamydia sp., Simkania sp. and Waddlia sp., have been associated with human disease, and others, such as Piscichlamydia sp. and Parilichlamydia sp., have been documented in association with diseases in animals. Their strict intracellular nature and the requirement for cell culture have been a confounding factor in characterizing the biology and pathogenicity of CLOs. Nevertheless, the genomes of seven CLO species have now been sequenced, providing new information on their potential ability to adapt to a wide range of hosts. As new isolation and diagnostic methods advance, we are able to further explore the richness of this phylum with further research likely to help define the true pathogenic potential of the CLOs while also providing insight into the origins of the 'traditional' chlamydiae. PMID:25854000

  6. Collateralized Debt Obligations and Credit Risk Transfer

    Microsoft Academic Search

    Douglas Lucas; Laurie Goodman; Frank Fabozzi

    2007-01-01

    Several studies have reported how new credit risk transfer vehicles have made it easier to reallocate large amounts of credit risk from the financial sector to the non-financial sector of the capital markets. In this article, we describe one of these new credit risk transfer vehicles, the collateralized debt obligation. Synthetic credit debt obligations utilize credit default swaps, another relatively

  7. 31 CFR 225.5 - Pledge of definitive Government obligations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... false Pledge of definitive Government obligations. 225.5 Section...ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS...225.5 Pledge of definitive Government obligations. (a) Type...

  8. 31 CFR 225.5 - Pledge of definitive Government obligations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... false Pledge of definitive Government obligations. 225.5 Section...ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS...225.5 Pledge of definitive Government obligations. (a) Type...

  9. 31 CFR 225.5 - Pledge of definitive Government obligations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... false Pledge of definitive Government obligations. 225.5 Section...ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS...225.5 Pledge of definitive Government obligations. (a) Type...

  10. 31 CFR 225.5 - Pledge of definitive Government obligations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... false Pledge of definitive Government obligations. 225.5 Section...ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS...225.5 Pledge of definitive Government obligations. (a) Type...

  11. 31 CFR 225.5 - Pledge of definitive Government obligations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... false Pledge of definitive Government obligations. 225.5 Section...ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS...225.5 Pledge of definitive Government obligations. (a) Type...

  12. 18 CFR 292.313 - Reinstatement of obligation to sell.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...utility of its obligation to sell electric energy, a qualifying cogeneration...utility's obligation to purchase electric energy under this section. Such...utility's obligation to sell electric energy under this section if the...

  13. 18 CFR 292.311 - Reinstatement of obligation to purchase.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...of its obligation to purchase electric energy, a qualifying cogeneration...utility's obligation to purchase electric energy under this section. Such application...utility's obligation to purchase electric energy under this section if the...

  14. 18 CFR 292.313 - Reinstatement of obligation to sell.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...utility of its obligation to sell electric energy, a qualifying cogeneration...utility's obligation to purchase electric energy under this section. Such...utility's obligation to sell electric energy under this section if the...

  15. 18 CFR 292.311 - Reinstatement of obligation to purchase.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...of its obligation to purchase electric energy, a qualifying cogeneration...utility's obligation to purchase electric energy under this section. Such application...utility's obligation to purchase electric energy under this section if the...

  16. 7 CFR 1488.12 - Coverage of bank obligations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Coverage of bank obligations. 1488.12...Agricultural Commodities From Private Stocks Under CCC Export Credit Sales Program (GSM-5) Bank Obligations and Repayment § 1488.12 Coverage of bank obligations. (a)...

  17. 7 CFR 1488.12 - Coverage of bank obligations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Coverage of bank obligations. 1488.12...Agricultural Commodities From Private Stocks Under CCC Export Credit Sales Program (GSM-5) Bank Obligations and Repayment § 1488.12 Coverage of bank obligations. (a)...

  18. 7 CFR 1488.12 - Coverage of bank obligations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Coverage of bank obligations. 1488.12...Agricultural Commodities From Private Stocks Under CCC Export Credit Sales Program (GSM-5) Bank Obligations and Repayment § 1488.12 Coverage of bank obligations. (a)...

  19. 7 CFR 1488.12 - Coverage of bank obligations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Coverage of bank obligations. 1488.12...Agricultural Commodities From Private Stocks Under CCC Export Credit Sales Program (GSM-5) Bank Obligations and Repayment § 1488.12 Coverage of bank obligations. (a)...

  20. 7 CFR 1488.12 - Coverage of bank obligations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Coverage of bank obligations. 1488.12...Agricultural Commodities From Private Stocks Under CCC Export Credit Sales Program (GSM-5) Bank Obligations and Repayment § 1488.12 Coverage of bank obligations. (a)...

  1. Intracellular biology and virulence determinants of Francisella tularensis revealed by transcriptional profiling inside macrophages

    PubMed Central

    Wehrly, Tara D.; Chong, Audrey; Virtaneva, Kimmo; Sturdevant, Dan E.; Child, Robert; Edwards, Jessica A.; Brouwer, Dedeke; Nair, Vinod; Fischer, Elizabeth R.; Wicke, Luke; Curda, Alissa J.; Kupko, John J.; Martens, Craig; Crane, Deborah D.; Bosio, Catharine M.; Porcella, Stephen F.; Celli, Jean

    2009-01-01

    Summary The highly infectious bacterium Francisella tularensis is a facultative intracellular pathogen, whose virulence requires proliferation inside host cells, including macrophages. Here we have performed a global transcriptional profiling of the highly virulent F. tularensis subsp. tularensis Schu S4 strain during its intracellular cycle within primary murine macrophages, to characterize its intracellular biology and identify pathogenic determinants based on their intracellular expression profiles. Phagocytosed bacteria rapidly responded to their intracellular environment and subsequently altered their transcriptional profile. Differential gene expression profiles were revealed that correlated with specific intracellular locale of the bacteria. Upregulation of general and oxidative stress response genes was a hallmark of the early phagosomal and late endosomal stages, while induction of transport and metabolic genes characterized the cytosolic replication stage. Expression of the Francisella Pathogenicity Island (FPI) genes, which are required for intracellular proliferation, increased during the intracellular cycle. Similarly, 27 chromosomal loci encoding putative hypothetical, secreted, outer membrane proteins or transcriptional regulators were identified as upregulated. Among these, deletion of FTT0383, FTT0369c or FTT1676 abolished the ability of Schu S4 to survive or proliferate intracellularly and cause lethality in mice, therefore identifying novel determinants of Francisella virulence from their intracellular expression profile. PMID:19388904

  2. Mechanisms of Francisella tularensis Intracellular Pathogenesis

    PubMed Central

    Celli, Jean

    2013-01-01

    Francisella tularensis is a zoonotic intracellular pathogen and the causative agent of the debilitating febrile illness tularemia. Although natural infections by F. tularensis are sporadic and generally localized, the low infectious dose, with the ability to be transmitted to humans via multiple routes and the potential to cause life-threatening infections, has led to concerns that this bacterium could be used as an agent of bioterror and released intentionally into the environment. Recent studies of F. tularensis and other closely related Francisella species have greatly increased our understanding of mechanisms used by this organism to infect and cause disease within the host. Here, we review the intracellular life cycle of Francisella and highlight key genetic determinants and/or pathways that contribute to the survival and proliferation of this bacterium within host cells. PMID:23545572

  3. 40 CFR 1043.30 - General obligations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...AND PM EMISSIONS FROM MARINE ENGINES AND VESSELS SUBJECT TO THE MARPOL PROTOCOL § 1043.30 General obligations. (a) 33...1907 prohibits any person from violating any provisions of the MARPOL Protocol, whether or not they are a manufacturer,...

  4. 40 CFR 1043.30 - General obligations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...AND PM EMISSIONS FROM MARINE ENGINES AND VESSELS SUBJECT TO THE MARPOL PROTOCOL § 1043.30 General obligations. (a) 33...1907 prohibits any person from violating any provisions of the MARPOL Protocol, whether or not they are a manufacturer,...

  5. 40 CFR 1043.30 - General obligations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...AND PM EMISSIONS FROM MARINE ENGINES AND VESSELS SUBJECT TO THE MARPOL PROTOCOL § 1043.30 General obligations. (a) 33...1907 prohibits any person from violating any provisions of the MARPOL Protocol, whether or not they are a manufacturer,...

  6. 40 CFR 1043.30 - General obligations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...AND PM EMISSIONS FROM MARINE ENGINES AND VESSELS SUBJECT TO THE MARPOL PROTOCOL § 1043.30 General obligations. (a) 33...1907 prohibits any person from violating any provisions of the MARPOL Protocol, whether or not they are a manufacturer,...

  7. 40 CFR 1043.30 - General obligations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...AND PM EMISSIONS FROM MARINE ENGINES AND VESSELS SUBJECT TO THE MARPOL PROTOCOL § 1043.30 General obligations. (a) 33...1907 prohibits any person from violating any provisions of the MARPOL Protocol, whether or not they are a manufacturer,...

  8. 19 CFR 10.2005 - Importer obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Panama Trade Promotion Agreement Import Requirements § 10.2005 Importer obligations. (a) General. An importer...

  9. 5 CFR 352.908 - Agency obligation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS REEMPLOYMENT RIGHTS Reemployment Rights After Service With the Panama Canal Commission § 352.908 Agency obligation. (a) Time limits. An employee is to be reemployed by the...

  10. 5 CFR 352.908 - Agency obligation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS REEMPLOYMENT RIGHTS Reemployment Rights After Service With the Panama Canal Commission § 352.908 Agency obligation. (a) Time limits. An employee is to be reemployed by the...

  11. 5 CFR 352.908 - Agency obligation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS REEMPLOYMENT RIGHTS Reemployment Rights After Service With the Panama Canal Commission § 352.908 Agency obligation. (a) Time limits. An employee is to be reemployed by the...

  12. 19 CFR 10.905 - Importer obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Peru Trade Promotion Agreement Import Requirements § 10.905 Importer obligations. (a) General. An importer who...

  13. 19 CFR 10.905 - Importer obligations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Peru Trade Promotion Agreement Import Requirements § 10.905 Importer obligations. (a) General. An importer who...

  14. 19 CFR 10.905 - Importer obligations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Peru Trade Promotion Agreement Import Requirements § 10.905 Importer obligations. (a) General. An importer who...

  15. 5 CFR 352.908 - Agency obligation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS REEMPLOYMENT RIGHTS Reemployment Rights After Service With the Panama Canal Commission § 352.908 Agency obligation. (a) Time limits. An employee is to be reemployed by...

  16. 5 CFR 352.908 - Agency obligation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS REEMPLOYMENT RIGHTS Reemployment Rights After Service With the Panama Canal Commission § 352.908 Agency obligation. (a) Time limits. An employee is to be reemployed by...

  17. Naval Engineering A National Naval Obligation

    E-print Network

    Chryssostomidis, Chryssostomos

    2000-05-16

    As part of its national obligations, ONR must ensure US world leadership in those unique technology areas that insure naval superiority. ONR accomplishes this mission through research, recruitment and education, maintaining ...

  18. 19 CFR 10.849 - Importer obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. Haitian Hemispheric Opportunity through Partnership Encouragement Act of 2006 § 10.849 Importer obligations. (a)...

  19. 19 CFR 10.849 - Importer obligations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. Haitian Hemispheric Opportunity through Partnership Encouragement Act of 2006 § 10.849 Importer obligations. (a)...

  20. 19 CFR 10.849 - Importer obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. Haitian Hemispheric Opportunity through Partnership Encouragement Act of 2006 § 10.849 Importer obligations. (a)...

  1. 19 CFR 10.849 - Importer obligations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. Haitian Hemispheric Opportunity through Partnership Encouragement Act of 2006 § 10.849 Importer obligations. (a)...

  2. 19 CFR 10.849 - Importer obligations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. Haitian Hemispheric Opportunity through Partnership Encouragement Act of 2006 § 10.849 Importer obligations. (a)...

  3. Risk and Valuation of Collateralized Debt Obligations

    Microsoft Academic Search

    Darrell Duffie; Nicolae Gârleanu

    2001-01-01

    This paper addresses the risk analysis and market valuation of collateralizeddebt obligations (CDOs). We illustrate the effects of correlation and prioritization for themarket valuation, diversity score, and risk of CDOs, in a simple jump-diffusion settingfor correlated default intensities.

  4. 46 CFR Sec. 11 - Guarantee obligations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...REPAIRS UNDER NATIONAL SHIPPING AUTHORITY MASTER LUMP SUM REPAIR CONTRACT-NSA-LUMPSUMREP Sec. 11 Guarantee obligations. (a) Under the provisions of Article 10 of the NSA-LUMPSUMREP Contract the Contractor's guarantee liability...

  5. 46 CFR Sec. 11 - Guarantee obligations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...REPAIRS UNDER NATIONAL SHIPPING AUTHORITY MASTER LUMP SUM REPAIR CONTRACT-NSA-LUMPSUMREP Sec. 11 Guarantee obligations. (a) Under the provisions of Article 10 of the NSA-LUMPSUMREP Contract the Contractor's guarantee liability...

  6. 46 CFR Sec. 11 - Guarantee obligations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...REPAIRS UNDER NATIONAL SHIPPING AUTHORITY MASTER LUMP SUM REPAIR CONTRACT-NSA-LUMPSUMREP Sec. 11 Guarantee obligations. (a) Under the provisions of Article 10 of the NSA-LUMPSUMREP Contract the Contractor's guarantee liability...

  7. 46 CFR Sec. 11 - Guarantee obligations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...REPAIRS UNDER NATIONAL SHIPPING AUTHORITY MASTER LUMP SUM REPAIR CONTRACT-NSA-LUMPSUMREP Sec. 11 Guarantee obligations. (a) Under the provisions of Article 10 of the NSA-LUMPSUMREP Contract the Contractor's guarantee liability...

  8. 46 CFR Sec. 11 - Guarantee obligations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...REPAIRS UNDER NATIONAL SHIPPING AUTHORITY MASTER LUMP SUM REPAIR CONTRACT-NSA-LUMPSUMREP Sec. 11 Guarantee obligations. (a) Under the provisions of Article 10 of the NSA-LUMPSUMREP Contract the Contractor's guarantee liability...

  9. 19 CFR 10.3005 - Importer obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Colombia Trade Promotion Agreement Import Requirements § 10.3005 Importer obligations. (a) General. An importer...

  10. 19 CFR 10.3005 - Importer obligations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Colombia Trade Promotion Agreement Import Requirements § 10.3005 Importer obligations. (a) General. An importer...

  11. Pathogen–host reorganization during Chlamydia invasion revealed by cryo-electron tomography

    PubMed Central

    Nans, Andrea; Saibil, Helen R; Hayward, Richard D

    2014-01-01

    Invasion of host cells is a key early event during bacterial infection, but the underlying pathogen–host interactions are yet to be fully visualized in three-dimensional detail. We have captured snapshots of the early stages of bacterial-mediated endocytosis in situ by exploiting the small size of chlamydial elementary bodies (EBs) for whole-cell cryo-electron tomography. Chlamydiae are obligate intracellular bacteria that infect eukaryotic cells and cause sexually transmitted infections and trachoma, the leading cause of preventable blindness. We demonstrate that Chlamydia trachomatis?LGV2 EBs are intrinsically polarized. One pole is characterized by a tubular inner membrane invagination, while the other exhibits asymmetric periplasmic expansion to accommodate an array of type III secretion systems (T3SSs). Strikingly, EBs orient with their T3SS-containing pole facing target cells, enabling the T3SSs to directly contact the cellular plasma membrane. This contact induces enveloping macropinosomes, actin-rich filopodia and phagocytic cups to zipper tightly around the internalizing bacteria. Once encapsulated into tight early vacuoles, EB polarity and the T3SSs are lost. Our findings reveal previously undescribed structural transitions in both pathogen and host during the initial steps of chlamydial invasion. PMID:24809274

  12. Pathogenic Rickettsia Species Acquire Vitronectin from Human Serum to Promote Resistance to Complement-mediated Killing

    PubMed Central

    Riley, Sean P.; Patterson, Jennifer L.; Nava, Samantha; Martinez, Juan J.

    2014-01-01

    SUMMARY Bacteria of the genus Rickettsia are transmitted from arthropod vectors and primarily infect cells of the mammalian endothelial system. Throughout this infectious cycle, the bacteria are exposed to the deleterious effects of serum complement. Using Rickettsia conorii, the etiologic agent of Mediterranean spotted fever (MSF), as a model rickettsial species, we have previously demonstrated that this class of pathogen interacts with human factor H to mediate partial survival in human serum. Herein, we demonstrate that R. conorii also interacts with the terminal complement complex inhibitor vitronectin (Vn). We further demonstrate that an evolutionarily conserved rickettsial antigen, Adr1/RC1281, interacts with human vitronectin and is sufficient to mediate resistance to serum killing when expressed at the outer-membrane of serum sensitive E. coli. Adr1 is an integral outer-membrane protein whose structure is predicted to contain eight membrane-embedded ?-strands and four “loop” regions that are exposed to extracellular milieu. Site-directed mutagenesis of Adr1 revealed that at least two predicted “loop” regions are required to mediate resistance to complement-mediated killing and vitronectin acquisition. These results demonstrate that rickettsial species have evolved multiple mechanisms to evade complement deposition and that evasion of killing in serum is an evolutionarily conserved virulence attribute for this genus of obligate intracellular pathogens. PMID:24286496

  13. Intracellular plant microbe associations: secretory pathways and the formation of perimicrobial compartments

    Microsoft Academic Search

    Sergey Ivanov; Elena Fedorova; Ton Bisseling

    2010-01-01

    Plants can establish intracellular interactions with symbiotic as well as pathogenic microbes. Such intracellular accommodation of microbes always involves the formation of a host membrane compartment - the interface between the cytoplasm of the host and the microbe. These are the so-called perimicrobial compartments. In this review we will focus on the rhizobial legume symbiosis in which the microbes are

  14. 1 Lipopolysaccharide Neutralizing Peptide-Porphyrin Conjugates for 2 Effective Photoinactivation and Intracellular Imaging of Gram-

    E-print Network

    Xing, Bengang

    and Intracellular Imaging of Gram- 3 Negative Bacteria Strains 4 Fang Liu, Annie Soh Yan Ni, Yingjie Lim, Harini tion of Gram-negative bacterial strains. The intracellular 14 fluorescent imaging and photodynamic activities against Gram-negative bacterial pathogens especially 19 for those with antibiotics resistance when

  15. Quantification and characterization of mucosa-associated and intracellular Escherichia coli in inflamatory bowel disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background and aims: Mucosa-associated E. coli are abundant in Crohn’s disease (CD) but whether these bacteria gain intracellular access within the mucosa is less certain. If E. coli does gain intracellular access in CD, the contribution of bacterial pathogenicity as opposed to a defect in host inna...

  16. Unravelling the biology of macrophage infection by gene expression profiling of intracellular Salmonella enterica

    Microsoft Academic Search

    Sofia Eriksson; Sacha Lucchini; Arthur Thompson; Mikael Rhen; Jay C. D. Hinton

    2003-01-01

    Summary For intracellular pathogens such as Salmonellae , Mycobacteriae and Brucellae , infection requires adaptation to the intracellular environment of the phagocytic cell . The transition from extracellular to intravacuolar environment has been expected to involve a global modulation of bacterial gene expres- sion, but the precise events have been difficult to determine. We now report the complete transcrip- tional

  17. Cell Biology Intracellular Transport

    E-print Network

    Schüler, Axel

    Keywords Ribozymes ncRNAs Cell Biology Intracellular Transport » PD Dr. Astrid Schön localization of complex RNA enzymes Contact PD Dr. Astrid Schön Molekulare Zelltherapie UNIVERSITÄT LEIPZIG-31373 fax +49 341 97-31379 astrid.schoen@bbz.uni-leipzig.de www.uni-leipzig.de/~mct/ Li, D.; WiLLkomm, D. k

  18. Unveiling the Intracellular Survival Gene Kit of Trypanosomatid Parasites

    PubMed Central

    Bartholomeu, Daniella Castanheira; de Paiva, Rita Marcia Cardoso; Mendes, Tiago A. O.; DaRocha, Wanderson D.; Teixeira, Santuza M. R.

    2014-01-01

    Trypanosomatids are unicellular protozoans of medical and economical relevance since they are the etiologic agents of infectious diseases in humans as well as livestock. Whereas Trypanosoma cruzi and different species of Leishmania are obligate intracellular parasites, Trypanosoma brucei and other trypanosomatids develop extracellularly throughout their entire life cycle. After their genomes have been sequenced, various comparative genomic studies aimed at identifying sequences involved with host cell invasion and intracellular survival have been described. However, for only a handful of genes, most of them present exclusively in the T. cruzi or Leishmania genomes, has there been any experimental evidence associating them with intracellular parasitism. With the increasing number of published complete genome sequences of members of the trypanosomatid family, including not only different Trypanosoma and Leishmania strains and subspecies but also trypanosomatids that do not infect humans or other mammals, we may now be able to contemplate a slightly better picture regarding the specific set of parasite factors that defines each organism's mode of living and the associated disease phenotypes. Here, we review the studies concerning T. cruzi and Leishmania genes that have been implicated with cell invasion and intracellular parasitism and also summarize the wealth of new information regarding the mode of living of intracellular parasites that is resulting from comparative genome studies that are based on increasingly larger trypanosomatid genome datasets. PMID:25474314

  19. Purification and proteomics of pathogen-modified vacuoles and membranes

    PubMed Central

    Herweg, Jo-Ana; Hansmeier, Nicole; Otto, Andreas; Geffken, Anna C.; Subbarayal, Prema; Prusty, Bhupesh K.; Becher, Dörte; Hensel, Michael; Schaible, Ulrich E.; Rudel, Thomas; Hilbi, Hubert

    2015-01-01

    Certain pathogenic bacteria adopt an intracellular lifestyle and proliferate in eukaryotic host cells. The intracellular niche protects the bacteria from cellular and humoral components of the mammalian immune system, and at the same time, allows the bacteria to gain access to otherwise restricted nutrient sources. Yet, intracellular protection and access to nutrients comes with a price, i.e., the bacteria need to overcome cell-autonomous defense mechanisms, such as the bactericidal endocytic pathway. While a few bacteria rupture the early phagosome and escape into the host cytoplasm, most intracellular pathogens form a distinct, degradation-resistant and replication-permissive membranous compartment. Intracellular bacteria that form unique pathogen vacuoles include Legionella, Mycobacterium, Chlamydia, Simkania, and Salmonella species. In order to understand the formation of these pathogen niches on a global scale and in a comprehensive and quantitative manner, an inventory of compartment-associated host factors is required. To this end, the intact pathogen compartments need to be isolated, purified and biochemically characterized. Here, we review recent progress on the isolation and purification of pathogen-modified vacuoles and membranes, as well as their proteomic characterization by mass spectrometry and different validation approaches. These studies provide the basis for further investigations on the specific mechanisms of pathogen-driven compartment formation.

  20. 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

  1. Intracellular Streptococcus pyogenes in Human Macrophages Display an Altered Gene Expression Profile

    Microsoft Academic Search

    Erika Hertzén; Linda Johansson; Rita Kansal; Alexander Hecht; Samira Dahesh; Marton Janos; Victor Nizet; Malak Kotb; Anna Norrby-Teglund

    2012-01-01

    Streptococcus pyogenes is an important human pathogen, which has recently gained recognition as an intracellular microorganism during the course of severe invasive infections such as necrotizing fasciitis. Although the surface anchored M protein has been identified as a pivotal factor affecting phagosomal maturation and S. pyogenes survival within macrophages, the overall transcriptional profile required for the pathogen to adapt and

  2. LOW PATHOGENIC POTENTIAL IN HETEROTROPHIC BACTERIA FROM POTABLE WATER

    EPA Science Inventory

    Forty-five isolates of HPC bacteria, most of which express virulence-related characteristics are being tested for pathogenicity in immunocompromised mice. All forty-five were negative for facultative intracellular pathogenicity. All twenty-three isolates tested thus far were a...

  3. Therapy of intracellular Staphylococcus aureus by tigecyclin

    PubMed Central

    2013-01-01

    Background In the fields of traumatology and orthopaedics staphylococci are the most frequently isolated pathogens. Staphylococcus aureus and Staphylococcus epidermidis are known to be the major causative agents of osteomyelitis. The increasing number of multiresistant Staphylococcus aureus and resistant coagulase-negative staphylococci as a trigger of complicated osteomyelitis and implant-associated infections is a major problem. Antibiotic therapy fails in 20% of cases. Therefore the development of novel antibiotics becomes necessary. Methods This study analyses tigecyclin, the first antibiotic of the glycylines, as a potential therapy for osteomyelitis caused by multiresistant Staphylococcus aureus. Therefore its intracellular activity and the potential use in polymethylmetacrylate-bone cement are examined. The intracellular activity of tigecyclin is determined by a human osteoblast infection model. The investigation of the biomechanical characteristics is conducted concerning the ISO 5833-guidelines. Results Tigecyclin shows in vitro an intracellular activity that ranges between the antimicrobial activity of gentamicin and rifampicin. A significant negative effect on the biomechanical characteristics with an impaired stability is detected after adding tigecyclin to polymethylmetacrylate-bone cement with a percentage of 1.225% per weight. Conclusions This study shows that tigecyclin might be a potent alternative for the systemic therapy of osteomyelitis and implant-associated infections whereas the local application has to be reconsidered individually. PMID:23738922

  4. Fungal Pathogens: Survival and Replication within Macrophages.

    PubMed

    Gilbert, Andrew S; Wheeler, Robert T; May, Robin C

    2014-11-10

    The innate immune system is a critical line of defense against pathogenic fungi. Macrophages act at an early stage of infection, detecting and phagocytizing infectious propagules. To avoid killing at this stage, fungal pathogens use diverse strategies ranging from evasion of uptake to intracellular parasitism. This article will discuss five of the most important human fungal pathogens (Candida albicans, Aspergillus fumigatus, Cryptococcus neoformans, Coccidiodes immitis, and Histoplasma capsulatum) and consider the strategies and virulence factors adopted by each to survive and replicate within macrophages. PMID:25384769

  5. Functional analysis of a lipolytic protein, a potential phytoplasma pathogenicity factor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wall-less bacteria known as phytoplasmas are obligate transkingdom parasites and pathogens of plants and insect vectors. These unusual bacteria possess some of the smallest genomes known among pathogenic bacteria, and have never been successfully isolated in artificial culture. Disease symptoms in...

  6. A Toxoplasma gondii protein with homology to intracellular type Na +\\/H + exchangers is important for osmoregulation and invasion

    Microsoft Academic Search

    Maria E. Francia; Sarah Wicher; Douglas A. Pace; Jack Sullivan; Silvia N. J. Moreno; Gustavo Arrizabalaga

    2011-01-01

    The obligate intracellular parasite Toxoplasma gondii is exposed to a variety of physiological conditions while propagating in an infected organism. The mechanisms by which Toxoplasma overcomes these dramatic changes in its environment are not known. In yeast and plants, ion detoxification and osmotic regulation are controlled by vacuolar compartments. A novel compartment named the plant-like vacuole or vacuolar compartment (PLV\\/VAC)

  7. 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

  8. 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

  9. Experimental evolution of nodule intracellular infection in legume symbionts

    PubMed Central

    Guan, Su Hua; Gris, Carine; Cruveiller, Stéphane; Pouzet, Cécile; Tasse, Lena; Leru, Aurélie; Maillard, Aline; Médigue, Claudine; Batut, Jacques; Masson-Boivin, Catherine; Capela, Delphine

    2013-01-01

    Soil bacteria known as rhizobia are able to establish an endosymbiosis with legumes that takes place in neoformed nodules in which intracellularly hosted bacteria fix nitrogen. Intracellular accommodation that facilitates nutrient exchange between the two partners and protects bacteria from plant defense reactions has been a major evolutionary step towards mutualism. Yet the forces that drove the selection of the late event of intracellular infection during rhizobium evolution are unknown. To address this question, we took advantage of the previous conversion of the plant pathogen Ralstonia solanacearum into a legume-nodulating bacterium that infected nodules only extracellularly. We experimentally evolved this draft rhizobium into intracellular endosymbionts using serial cycles of legume-bacterium cocultures. The three derived lineages rapidly gained intracellular infection capacity, revealing that the legume is a highly selective environment for the evolution of this trait. From genome resequencing, we identified in each lineage a mutation responsible for the extracellular–intracellular transition. All three mutations target virulence regulators, strongly suggesting that several virulence-associated functions interfere with intracellular infection. We provide evidence that the adaptive mutations were selected for their positive effect on nodulation. Moreover, we showed that inactivation of the type three secretion system of R. solanacearum that initially allowed the ancestral draft rhizobium to nodulate, was also required to permit intracellular infection, suggesting a similar checkpoint for bacterial invasion at the early nodulation/root infection and late nodule cell entry levels. We discuss our findings with respect to the spread and maintenance of intracellular infection in rhizobial lineages during evolutionary times. PMID:23426010

  10. 31 CFR 1021.311 - Filing obligations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Money and Finance (Continued) FINANCIAL CRIMES ENFORCEMENT NETWORK, DEPARTMENT OF THE...TREASURY RULES FOR CASINOS AND CARD CLUBS Reports Required To Be Made By Casinos and Card...obligations. Each casino shall file a report of each transaction in currency,...

  11. 31 CFR 1021.311 - Filing obligations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Money and Finance (Continued) FINANCIAL CRIMES ENFORCEMENT NETWORK, DEPARTMENT OF THE...TREASURY RULES FOR CASINOS AND CARD CLUBS Reports Required To Be Made By Casinos and Card...obligations. Each casino shall file a report of each transaction in currency,...

  12. 31 CFR 1021.311 - Filing obligations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Money and Finance (Continued) FINANCIAL CRIMES ENFORCEMENT NETWORK, DEPARTMENT OF THE...TREASURY RULES FOR CASINOS AND CARD CLUBS Reports Required To Be Made By Casinos and Card...obligations. Each casino shall file a report of each transaction in currency,...

  13. The author’s opportunity and obligation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peer review is a critical component of the scientific method and therefore should be an obligation for everyone who desires to publish their research results in refereed journals. This editorial is written to address a specific problem being encountered by editors of Soil & Tillage Research, but the...

  14. Fetal Diagnosis – Obligations of the Clinician

    Microsoft Academic Search

    Samuel Menahem; Lynn Gillam

    2007-01-01

    Fetal echocardiography allows for accurate diagnosis of major heart abnormalities by 16–18 weeks. The parents have up to 22 weeks to consider possible termination. What are the obligations of the clinician once an abnormality is found? Should only information be provided or is there a role in influencing the parents’ decision? Two diverse examples are provided to discuss these questions.

  15. Intracellular sensing of complement C3 activates cell autonomous immunity

    PubMed Central

    Tam, Jerry C.H.; Bidgood, Susanna R.; McEwan, William A.; James, Leo C.

    2014-01-01

    Pathogens traverse multiple barriers during infection including cell membranes. Here we show that during this transition pathogens carry covalently attached complement C3 into the cell, triggering immediate signalling and effector responses. Sensing of C3 in the cytosol activates MAVS-dependent signalling cascades and induces proinflammatory cytokine secretion. C3 also flags viruses for rapid proteasomal degradation, thereby preventing their replication. This system can detect both viral and bacterial pathogens but is antagonized by enteroviruses, such as rhinovirus and poliovirus, which cleave C3 using their 3C protease. The antiviral Rupintrivir inhibits 3C protease and prevents C3 cleavage, rendering enteroviruses susceptible to intracellular complement sensing. Thus, complement C3 allows cells to detect and disable pathogens that have invaded the cytosol. PMID:25190799

  16. 24 CFR 582.410 - Obligation and deobligation of funds.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...SECRETARY FOR COMMUNITY PLANNING AND DEVELOPMENT, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT COMMUNITY FACILITIES SHELTER PLUS CARE Administration § 582.410 Obligation and deobligation of funds. (a) Obligation of funds....

  17. 24 CFR 582.410 - Obligation and deobligation of funds.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...SECRETARY FOR COMMUNITY PLANNING AND DEVELOPMENT, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT COMMUNITY FACILITIES SHELTER PLUS CARE Administration § 582.410 Obligation and deobligation of funds. (a) Obligation of funds....

  18. 24 CFR 582.410 - Obligation and deobligation of funds.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...SECRETARY FOR COMMUNITY PLANNING AND DEVELOPMENT, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT COMMUNITY FACILITIES SHELTER PLUS CARE Administration § 582.410 Obligation and deobligation of funds. (a) Obligation of funds....

  19. 24 CFR 582.410 - Obligation and deobligation of funds.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...SECRETARY FOR COMMUNITY PLANNING AND DEVELOPMENT, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT COMMUNITY FACILITIES SHELTER PLUS CARE Administration § 582.410 Obligation and deobligation of funds. (a) Obligation of funds....

  20. 24 CFR 582.410 - Obligation and deobligation of funds.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...SECRETARY FOR COMMUNITY PLANNING AND DEVELOPMENT, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT COMMUNITY FACILITIES SHELTER PLUS CARE Administration § 582.410 Obligation and deobligation of funds. (a) Obligation of funds....

  1. 47 CFR 22.878 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Obligation to abate unacceptable interference. 22.878 Section 22.878 Telecommunication... Obligation to abate unacceptable interference. This section applies only...contributes to causing unacceptable interference to a non-cellular part 90...

  2. 47 CFR 22.971 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Obligation to abate unacceptable interference. 22.971 Section 22.971 Telecommunication... Obligation to abate unacceptable interference. (a) Strict Responsibility...contributes to causing unacceptable interference to a non-cellular part 90 of...

  3. 47 CFR 22.878 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Obligation to abate unacceptable interference. 22.878 Section 22.878 Telecommunication... Obligation to abate unacceptable interference. This section applies only...contributes to causing unacceptable interference to a non-cellular part 90...

  4. 47 CFR 22.878 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Obligation to abate unacceptable interference. 22.878 Section 22.878 Telecommunication... Obligation to abate unacceptable interference. This section applies only...contributes to causing unacceptable interference to a non-cellular part 90...

  5. 47 CFR 22.971 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Obligation to abate unacceptable interference. 22.971 Section 22.971 Telecommunication... Obligation to abate unacceptable interference. (a) Strict Responsibility...contributes to causing unacceptable interference to a non-cellular part 90 of...

  6. 47 CFR 22.971 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Obligation to abate unacceptable interference. 22.971 Section 22.971 Telecommunication... Obligation to abate unacceptable interference. (a) Strict Responsibility...contributes to causing unacceptable interference to a non-cellular part 90 of...

  7. 47 CFR 22.878 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Obligation to abate unacceptable interference. 22.878 Section 22.878 Telecommunication... Obligation to abate unacceptable interference. This section applies only...contributes to causing unacceptable interference to a non-cellular part 90...

  8. 47 CFR 22.971 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Obligation to abate unacceptable interference. 22.971 Section 22.971 Telecommunication... Obligation to abate unacceptable interference. (a) Strict Responsibility...contributes to causing unacceptable interference to a non-cellular part 90 of...

  9. 47 CFR 22.971 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Obligation to abate unacceptable interference. 22.971 Section 22.971 Telecommunication... Obligation to abate unacceptable interference. (a) Strict Responsibility...contributes to causing unacceptable interference to a non-cellular part 90 of...

  10. 47 CFR 22.878 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Obligation to abate unacceptable interference. 22.878 Section 22.878 Telecommunication... Obligation to abate unacceptable interference. This section applies only...contributes to causing unacceptable interference to a non-cellular part 90...

  11. 29 CFR 500.100 - Vehicle safety obligations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...100 Vehicle safety obligations...obligations. Each farm labor contractor...conforms to vehicle safety standards prescribed...the Secretary of Labor under the Act and...Federal and State safety standards. Each farm labor...

  12. 29 CFR 500.100 - Vehicle safety obligations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...100 Vehicle safety obligations...obligations. Each farm labor contractor...conforms to vehicle safety standards prescribed...the Secretary of Labor under the Act and...Federal and State safety standards. Each farm labor...

  13. 47 CFR 76.56 - Signal carriage obligations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Telecommunication 4 2012-10-01 2012-10-01 false Signal carriage obligations. 76.56 Section 76.56...TELEVISION SERVICE Carriage of Television Broadcast Signals § 76.56 Signal carriage obligations. (a) Carriage of...

  14. 47 CFR 76.56 - Signal carriage obligations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Telecommunication 4 2014-10-01 2014-10-01 false Signal carriage obligations. 76.56 Section 76.56...TELEVISION SERVICE Carriage of Television Broadcast Signals § 76.56 Signal carriage obligations. (a) Carriage of...

  15. 47 CFR 76.56 - Signal carriage obligations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Telecommunication 4 2013-10-01 2013-10-01 false Signal carriage obligations. 76.56 Section 76.56...TELEVISION SERVICE Carriage of Television Broadcast Signals § 76.56 Signal carriage obligations. (a) Carriage of...

  16. 12 CFR 966.2 - Issuance of consolidated obligations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...Section 966.2 Banks and Banking FEDERAL HOUSING FINANCE BOARD FEDERAL HOME LOAN BANK LIABILITIES CONSOLIDATED... (a) Consolidated obligations issued by the Finance Board. The Finance Board may issue consolidated obligations...

  17. 12 CFR 966.2 - Issuance of consolidated obligations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...Section 966.2 Banks and Banking FEDERAL HOUSING FINANCE BOARD FEDERAL HOME LOAN BANK LIABILITIES CONSOLIDATED... (a) Consolidated obligations issued by the Finance Board. The Finance Board may issue consolidated obligations...

  18. 18 CFR 367.22 - Accounting for asset retirement obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Accounting for asset retirement obligations...General Instructions § 367.22 Accounting for asset retirement obligations...retirement cost must be stated at the fair value of the asset retirement...

  19. 18 CFR 367.22 - Accounting for asset retirement obligations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Accounting for asset retirement obligations...General Instructions § 367.22 Accounting for asset retirement obligations...retirement cost must be stated at the fair value of the asset retirement...

  20. 18 CFR 367.22 - Accounting for asset retirement obligations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Accounting for asset retirement obligations...General Instructions § 367.22 Accounting for asset retirement obligations...retirement cost must be stated at the fair value of the asset retirement...

  1. 18 CFR 367.22 - Accounting for asset retirement obligations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Accounting for asset retirement obligations...General Instructions § 367.22 Accounting for asset retirement obligations...retirement cost must be stated at the fair value of the asset retirement...

  2. 29 CFR 500.100 - Vehicle safety obligations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Vehicle safety obligations. 500.100 Section 500.100 Labor Regulations Relating to Labor (Continued...Health for Migrant Workers Motor Vehicle Safety § 500.100 Vehicle safety obligations. (a)...

  3. 13 CFR 500.213 - Termination of obligations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Termination of obligations. 500.213 Section 500.213 Business Credit and Assistance EMERGENCY...GUARANTEED LOAN PROGRAM Oil and Gas Guaranteed Loans § 500.213 Termination of obligations. (a)...

  4. 16 CFR 436.2 - Obligation to furnish documents.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...Commercial Practices FEDERAL TRADE COMMISSION TRADE REGULATION RULES DISCLOSURE REQUIREMENTS AND PROHIBITIONS CONCERNING FRANCHISING Franchisors' Obligations § 436.2 Obligation to furnish documents. In connection with the offer or...

  5. 34 CFR 685.212 - Discharge of a loan obligation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 false Discharge of a loan obligation. 685.212 Section 685...EDUCATION WILLIAM D. FORD FEDERAL DIRECT LOAN PROGRAM Borrower Provisions § 685.212 Discharge of a loan obligation. (a) Death. (1)...

  6. 34 CFR 685.212 - Discharge of a loan obligation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 2013-07-01 false Discharge of a loan obligation. 685.212 Section 685...CONTINUED) WILLIAM D. FORD FEDERAL DIRECT LOAN PROGRAM Borrower Provisions § 685.212 Discharge of a loan obligation. (a) Death. (1)...

  7. 34 CFR 685.212 - Discharge of a loan obligation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 false Discharge of a loan obligation. 685.212 Section 685...CONTINUED) WILLIAM D. FORD FEDERAL DIRECT LOAN PROGRAM Borrower Provisions § 685.212 Discharge of a loan obligation. (a) Death. (1)...

  8. 34 CFR 685.212 - Discharge of a loan obligation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 2012-07-01 false Discharge of a loan obligation. 685.212 Section 685...CONTINUED) WILLIAM D. FORD FEDERAL DIRECT LOAN PROGRAM Borrower Provisions § 685.212 Discharge of a loan obligation. (a) Death. (1)...

  9. 43 CFR 3162.2-1 - Drilling and producing obligations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Interior 2 2014-10-01 2014-10-01 false Drilling and producing obligations. 3162.2-1 Section 3162...for Operating Rights Owners and Operators § 3162.2-1 Drilling and producing obligations. (a) The operator,...

  10. 25 CFR 226.9 - Rental and drilling obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 false Rental and drilling obligations. 226.9 Section 226...and Royalty § 226.9 Rental and drilling obligations. (a) Oil leases...the date the Superintendent consents to drilling on any restricted homestead...

  11. 43 CFR 3162.2-1 - Drilling and producing obligations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Interior 2 2011-10-01 2011-10-01 false Drilling and producing obligations. 3162.2-1 Section 3162...for Operating Rights Owners and Operators § 3162.2-1 Drilling and producing obligations. (a) The operator,...

  12. 25 CFR 226.9 - Rental and drilling obligations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 false Rental and drilling obligations. 226.9 Section 226...and Royalty § 226.9 Rental and drilling obligations. (a) Oil leases...the date the Superintendent consents to drilling on any restricted homestead...

  13. 25 CFR 226.9 - Rental and drilling obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 2014-04-01 false Rental and drilling obligations. 226.9 Section 226...and Royalty § 226.9 Rental and drilling obligations. (a) Oil leases...the date the Superintendent consents to drilling on any restricted homestead...

  14. 43 CFR 3162.2-1 - Drilling and producing obligations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Interior 2 2012-10-01 2012-10-01 false Drilling and producing obligations. 3162.2-1 Section 3162...for Operating Rights Owners and Operators § 3162.2-1 Drilling and producing obligations. (a) The operator,...

  15. 43 CFR 3162.2-1 - Drilling and producing obligations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Interior 2 2013-10-01 2013-10-01 false Drilling and producing obligations. 3162.2-1 Section 3162...for Operating Rights Owners and Operators § 3162.2-1 Drilling and producing obligations. (a) The operator,...

  16. 25 CFR 226.9 - Rental and drilling obligations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2011-04-01 true Rental and drilling obligations. 226.9 Section 226...and Royalty § 226.9 Rental and drilling obligations. (a) Oil leases...the date the Superintendent consents to drilling on any restricted homestead...

  17. 25 CFR 226.9 - Rental and drilling obligations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 false Rental and drilling obligations. 226.9 Section 226...and Royalty § 226.9 Rental and drilling obligations. (a) Oil leases...the date the Superintendent consents to drilling on any restricted homestead...

  18. 12 CFR 560.42 - State and local government obligations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...Federal Savings Associations § 560.42 State and local government obligations. (a) What limitations apply? Pursuant to HOLA section 5(c)(1)(H), a Federal savings association (“you”) may invest in obligations issued by any state,...

  19. 12 CFR 560.42 - State and local government obligations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...Federal Savings Associations § 560.42 State and local government obligations. (a) What limitations apply? Pursuant to HOLA section 5(c)(1)(H), a Federal savings association (“you”) may invest in obligations issued by any state,...

  20. 12 CFR 160.42 - State and local government obligations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...LENDING AND INVESTMENT § 160.42 State and local government obligations. (a) What limitations apply? Pursuant to HOLA section 5(c)(1)(H), a Federal savings association (“you”) may invest in obligations issued by any state,...

  1. 12 CFR 160.42 - State and local government obligations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...DEPARTMENT OF THE TREASURY LENDING AND INVESTMENT § 160.42 State and local government obligations. (a) Pursuant to HOLA section 5(c)(1)(H), a Federal savings association may invest in obligations issued by any state, territory,...

  2. 12 CFR 560.42 - State and local government obligations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...Federal Savings Associations § 560.42 State and local government obligations. (a) What limitations apply? Pursuant to HOLA section 5(c)(1)(H), a Federal savings association (“you”) may invest in obligations issued by any state,...

  3. 12 CFR 160.42 - State and local government obligations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...DEPARTMENT OF THE TREASURY LENDING AND INVESTMENT § 160.42 State and local government obligations. (a) Pursuant to HOLA section 5(c)(1)(H), a Federal savings association may invest in obligations issued by any state, territory,...

  4. Carbon based nutrition of Staphylococcus aureus and the role of sugar phosphate transporters in intracellular bacterial replication 

    E-print Network

    Bell, John Alexander

    2014-06-28

    The Gram positive bacterium Staphylococcus aureus is a major cause of human disease in industrialized countries. This multifaceted pathogen is adapted to thrive in a variety of host niches, including the intracellular ...

  5. 34 CFR 686.43 - Obligation to repay the grant.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Obligation to repay the grant. 686.43 Section 686.43 Education...FOR COLLEGE AND HIGHER EDUCATION (TEACH) GRANT PROGRAM Service and Repayment Obligations § 686.43 Obligation to repay the grant. (a) The TEACH Grant amounts...

  6. 34 CFR 686.43 - Obligation to repay the grant.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Obligation to repay the grant. 686.43 Section 686.43 Education...FOR COLLEGE AND HIGHER EDUCATION (TEACH) GRANT PROGRAM Service and Repayment Obligations § 686.43 Obligation to repay the grant. (a) The TEACH Grant amounts...

  7. 34 CFR 686.43 - Obligation to repay the grant.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Obligation to repay the grant. 686.43 Section 686.43 Education...FOR COLLEGE AND HIGHER EDUCATION (TEACH) GRANT PROGRAM Service and Repayment Obligations § 686.43 Obligation to repay the grant. (a) The TEACH Grant amounts...

  8. 34 CFR 686.43 - Obligation to repay the grant.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Obligation to repay the grant. 686.43 Section 686.43 Education...FOR COLLEGE AND HIGHER EDUCATION (TEACH) GRANT PROGRAM Service and Repayment Obligations § 686.43 Obligation to repay the grant. (a) The TEACH Grant amounts...

  9. 34 CFR 686.43 - Obligation to repay the grant.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Obligation to repay the grant. 686.43 Section 686.43 Education...FOR COLLEGE AND HIGHER EDUCATION (TEACH) GRANT PROGRAM Service and Repayment Obligations § 686.43 Obligation to repay the grant. (a) The TEACH Grant amounts...

  10. INTRACELLULAR SURVIVAL OF STAPHYLOCOCCI

    PubMed Central

    Kapral, Frank A.; Shayegani, Mehdi Gh.

    1959-01-01

    A tissue culture procedure is described which permits the quantitative evaluation of the intracellular survival of staphylococci within leucocytes. Staphylococcus aureus survived, but did not multiply, within neutrophils and monocytes of normal rabbits. The same was true of normal human blood leucocytes. Staphylococcus albus on the other hand was destroyed by these cells under the same conditions. Rat monocytes destroyed S. aureus and S. albus with equal facility. Although most experiments were carried out in the presence of 50 µg. streptomycin/ml., similar results were obtained without the use of this antibiotic. The applications of the tissue culture procedure with regard to studies on virulence and immunity in staphylococcal disease are discussed. PMID:13664874

  11. Pyrimidine metabolism by intracellular Chlamydia psittaci.

    PubMed Central

    McClarty, G; Qin, B

    1993-01-01

    Pyrimidine metabolism was studied in the obligate intracellular bacterium Chlamydia psittaci AA Mp in the wild type and a variety of mutant host cell lines with well-defined mutations affecting pyrimidine metabolism. C. psittaci AA Mp cannot synthesize pyrimidines de novo, as assessed by its inability to incorporate aspartic acid into nucleic acid pyrimidines. In addition, the parasite cannot take UTP, CTP, or dCTP from the host cell, nor can it salvage exogenously supplied uridine, cytidine, or deoxycytidine. The primary source of pyrimidine nucleotides is via the salvage of uracil by a uracil phosphoribosyltransferase. Uracil phosphoribosyltransferase activity was detected in crude extracts prepared from highly purified C. psittaci AA Mp reticulate bodies. The presence of CTP synthetase and ribonucleotide reductase is implicated from the incorporation of uracil into nucleic acid cytosine and deoxycytidine. Deoxyuridine was used by the parasite only after cleavage to uracil. C. psittaci AA Mp grew poorly in mutant host cell lines auxotrophic for thymidine. Furthermore, the parasite could not synthesize thymidine nucleotides de novo. C. psittaci AA Mp could take TTP directly from the host cell. In addition, the parasite could incorporate exogenous thymidine and thymine into DNA. Thymidine kinase activity and thymidine-cleaving activity were detected in C. psittaci AA Mp reticulate body extract. Thus, thymidine salvage was totally independent of other pyrimidine salvage. PMID:8335624

  12. Metabolism of the vacuolar pathogen Legionella and implications for virulence

    PubMed Central

    Manske, Christian; Hilbi, Hubert

    2014-01-01

    Legionella pneumophila is a ubiquitous environmental bacterium that thrives in fresh water habitats, either as planktonic form or as part of biofilms. The bacteria also grow intracellularly in free-living protozoa as well as in mammalian alveolar macrophages, thus triggering a potentially fatal pneumonia called “Legionnaires' disease.” To establish its intracellular niche termed the “Legionella-containing vacuole” (LCV), L. pneumophila employs a type IV secretion system and translocates ~300 different “effector” proteins into host cells. The pathogen switches between two distinct forms to grow in its extra- or intracellular niches: transmissive bacteria are virulent for phagocytes, and replicative bacteria multiply within their hosts. The switch between these forms is regulated by different metabolic cues that signal conditions favorable for replication or transmission, respectively, causing a tight link between metabolism and virulence of the bacteria. Amino acids represent the prime carbon and energy source of extra- or intracellularly growing L. pneumophila. Yet, the genome sequences of several Legionella spp. as well as transcriptome and proteome data and metabolism studies indicate that the bacteria possess broad catabolic capacities and also utilize carbohydrates such as glucose. Accordingly, L. pneumophila mutant strains lacking catabolic genes show intracellular growth defects, and thus, intracellular metabolism and virulence of the pathogen are intimately connected. In this review we will summarize recent findings on the extra- and intracellular metabolism of L. pneumophila using genetic, biochemical and cellular microbial approaches. Recent progress in this field sheds light on the complex interplay between metabolism, differentiation and virulence of the pathogen. PMID:25250244

  13. Do family doctors have an obligation to facilitate research?

    PubMed

    Ives, Jonathan; Draper, Heather; Damery, Sarah; Wilson, Sue

    2009-12-01

    In the third of a series of articles examining ethical issues in primary care research, we argue that family doctors, when considering what they ought to do in relation to research, have a positive obligation to participate in research and that one means of discharging this obligation is to collaborate in research studies by aiding recruitment. We offer three arguments in support of this obligation-arguments from fairness, reason and utility. We then go on to specify a series of conditions on this obligation which take into account that doctors have many other obligations. These are the conditions of financial remuneration, reciprocity and ability. PMID:19589883

  14. Informed consent: Enforcing pharmaceutical companies' obligations abroad.

    PubMed

    Lee, Stacey B

    2010-01-01

    The past several years have seen an evolution in the obligations of pharmaceutical companies conducting clinical trials abroad. Key players, such as international human rights organizations, multinational pharmaceutical companies, the United States government and courts, and the media, have played a significant role in defining these obligations. This article examines how such obligations have developed through the lens of past, present, and future recommendations for informed consent protections. In doing so, this article suggests that, no matter how robust obligations appear, they will continue to fall short of providing meaningful protection until they are accompanied by a substantive enforcement mechanism that holds multinational pharmaceutical companies accountable for their conduct. Issues of national sovereignty, particularly in the United States, will continue to prevent meaningful enforcement by an international tribunal or through one universally adopted code of ethics. This article argues that, rather than continuing to pursue an untenable international approach, the Alien Torts Statute (ATS) offers a viable enforcement mechanism, at least for US-based pharmaceutical companies. Recent federal appellate court precedent interpreting the ATS provides the mechanism for granting victims redress and enforcing accountability of sponsors (usually pharmaceutical companies and research and academic institutions) for informed consent misconduct. Substantive human rights protections are vital in order to ensure that every person can realize the "right to health." This article concludes that by building on the federal appellate court's ATS analysis, which grants foreign trial participants the right to pursue claims of human rights violations in US courts, a mechanism can be created for enforcing not only substantive informed consent, but also human rights protections. PMID:20930251

  15. Live cell imaging of intracellular Salmonella enterica.

    PubMed

    Kehl, Alexander; Hensel, Michael

    2015-01-01

    During the intracellular phase of the pathogenic lifestyle, Salmonella enterica massively alters the endosomal system of its host cells. Two hallmarks are the remodeling of phagosomes into the Salmonella-containing vacuole (SCV) as a replicative niche, and the formation of tubular structures, such as Salmonella-induced filaments (SIFs). To study the dynamics and the fate of these Salmonella-specific compartments, live cell imaging (LCI) is a method of choice. In this chapter, we compare currently used microscopy techniques and focus on considerations and requirements specific for LCI. Detailed protocols for LCI of Salmonella infection with either confocal laser scanning microscopy (CLSM) or spinning disk confocal microscopy (SDCM) are provided. PMID:25253257

  16. Obligate biotrophy features unraveled by the genomic analysis of the rust fungi, Melampsora larici-populina and Puccinia graminis f. sp. tritici

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rust fungi are some of the most devastating pathogens of crop plants. They are obligate biotrophs, which extract nutrients only from living plant tissues and cannot grow apart from their hosts. Their lifestyle has slowed the dissection of molecular mechanisms underlying host invasion and avoidance...

  17. Quantitative proteomics of intracellular Porphyromonas gingivalis

    PubMed Central

    Xia, Qiangwei; Wang, Tiansong; Taub, Fred; Park, Yoonsuk; Capestany, Cindy A.; Lamont, Richard J.; Hackett, Murray

    2009-01-01

    Whole-cell quantitative proteomic analyses were conducted to investigate the change from an extracellular to intracellular lifestyle for Porphyromonas gingivalis, a Gram-negative intracellular pathogen associated with periodontal disease. Global protein abundance data for P. gingivalis strain ATCC 33277 internalized for 18 hours within human gingival epithelial cells and controls exposed to gingival cell culture medium were obtained at sufficient coverage to provide strong evidence that these changes are profound. A total of 385 proteins were over-expressed in internalized P. gingivalis relative to controls; 240 proteins were shown to be under-expressed. This represented in total about 28% of the protein encoding ORFs annotated for this organism, and slightly less than half of the proteins that were observed experimentally. Production of several proteases, including the classical virulence factors RgpA, RgpB, and Kgp, was decreased. A separate validation study was carried out in which a 16-fold dilution of the P. gingivalis proteome was compared to the undiluted sample in order to assess the quantitative false negative rate (all ratios truly alternative). Truly null (no change) abundance ratios from technical replicates were used to assess the rate of quantitative false positives over the entire proteome. A global comparison between the direction of abundance change observed and previously published bioinformatic gene pair predictions for P. gingivalis will assist with future studies of P. gingivalis gene regulation and operon prediction. PMID:17979175

  18. Receptor-mediated recognition of mycobacterial pathogens.

    PubMed

    Killick, Kate E; Ní Cheallaigh, Clíona; O'Farrelly, Cliona; Hokamp, Karsten; MacHugh, David E; Harris, James

    2013-09-01

    Mycobacteria are a genus of bacteria that range from the non-pathogenic Mycobacterium smegmatis to Mycobacterium tuberculosis, the causative agent of tuberculosis in humans. Mycobacteria primarily infect host tissues through inhalation or ingestion. They are phagocytosed by host macrophages and dendritic cells. Here, conserved pathogen-associated molecular patterns (PAMPs) on the surface of mycobacteria are recognized by phagocytic pattern recognition receptors (PRRs). Several families of PRRs have been shown to non-opsonically recognize mycobacterial PAMPs, including membrane-bound C-type lectin receptors, membrane-bound and cytosolic Toll-like receptors and cytosolic NOD-like receptors. Recently, a possible role for intracellular cytosolic PRRs in the recognition of mycobacterial pathogens has been proposed. Here, we discuss currentideas on receptor-mediated recognition of mycobacterial pathogens by macrophages and dendritic cells. PMID:23795683

  19. Prison Break: Pathogens' Strategies To Egress from Host Cells

    PubMed Central

    Friedrich, Nikolas; Hagedorn, Monica; Soldati-Favre, Dominique

    2012-01-01

    Summary: A wide spectrum of pathogenic bacteria and protozoa has adapted to an intracellular life-style, which presents several advantages, including accessibility to host cell metabolites and protection from the host immune system. Intracellular pathogens have developed strategies to enter and exit their host cells while optimizing survival and replication, progression through the life cycle, and transmission. Over the last decades, research has focused primarily on entry, while the exit process has suffered from neglect. However, pathogen exit is of fundamental importance because of its intimate association with dissemination, transmission, and inflammation. Hence, to fully understand virulence mechanisms of intracellular pathogens at cellular and systemic levels, it is essential to consider exit mechanisms to be a key step in infection. Exit from the host cell was initially viewed as a passive process, driven mainly by physical stress as a consequence of the explosive replication of the pathogen. It is now recognized as a complex, strategic process termed “egress,” which is just as well orchestrated and temporally defined as entry into the host and relies on a dynamic interplay between host and pathogen factors. This review compares egress strategies of bacteria, pathogenic yeast, and kinetoplastid and apicomplexan parasites. Emphasis is given to recent advances in the biology of egress in mycobacteria and apicomplexans. PMID:23204363

  20. INTRACELLULAR SIGNALING AND DEVELOPMENTAL NEUROTOXICITY.

    EPA Science Inventory

    A book chapter in ?Molecular Toxicology: Transcriptional Targets? reviewed the role of intracellular signaling in the developmental neurotoxicity of environmental chemicals. This chapter covered a number of aspects including the development of the nervous system, role of intrace...

  1. Obligations of an academic and clinical oncologist: historical reflections.

    PubMed

    Johnson, David H

    2014-01-01

    Obligations are derived from one's core values-those fundamental, enduring, deeply held beliefs that guide one's everyday actions. Gandhi stated it more eloquently than I ever could: "Your beliefs become your thoughts, your thoughts become your words, your words become your actions, your actions become your habits, your habits become your values, your values become your destiny." So what are the obligations of the academic oncologist and clinician? I believe there are a few indubitable and fundamental obligations: professionalism, patient care, stewardship, maintenance of knowledge, productivity, and mentorship). I might add that I do not see these obligations as unique to the academician but rather applicable to all physicians. PMID:24857063

  2. Obligately barophilic bacterium from the Mariana trench.

    PubMed

    Yayanos, A A; Dietz, A S; Van Boxtel, R

    1981-08-01

    An amphipod (Hirondellea gigas) was retrieved with decompression in an insulated trap from an ocean depth of 10,476 m. Bacterial isolates were obtained from the dead and cold animal by using silica gel medium incubated at 1000 bars (1 bar = 10(5) Pa) and 2 degrees C. The isolate designated MT41 was found to be obligately barophilic and did not grow at a pressure close to that of 380 bars found at average depths of the sea. The optimal generation time of about 25 hr was at 2 degrees C and 690 bars. The generation time at 2 degrees C and 1,035 bars, a pressure close to that at the depth of origin, was about 33 hr. Among the conclusions are: (i) pressure is an important determinant of zonation along the water column of the sea; (ii) some obligately barophilic bacteria survive decompressions; (iii) the pressure of optimal growth at 2 degrees C appears to be less than the pressure at the depth of origin and may be diagnostic for the depth of origin; (iv) rates of reproduction are slow yet significant and an order of magnitude greater than previously thought; and (v) much of deep-sea microbiology may have been done with spurious deep-sea organisms due to warming of samples. PMID:6946468

  3. Trimethylamine metabolism in obligate and facultative methylotrophs

    PubMed Central

    Colby, J.; Zatman, L. J.

    1973-01-01

    1. Twelve bacterial isolates that grow with trimethylamine as sole source of carbon and energy were obtained in pure culture. All the isolates grow on methylamine, dimethylamine and trimethylamine. One isolate, bacterium 4B6, grows only on these methylamines whereas another isolate, bacterium C2A1, also grows on methanol but neither grows on methane; these two organisms are obligate methylotrophs. The other ten isolates grow on a variety of Ci and other organic compounds and are therefore facultative methylotrophs. 2. Washed suspensions of the obligate methylotrophs bacteria 4B6 and C2A1, and of the facultative methylotrophs bacterium 5B1 and Pseudomonas 3A2, all grown on trimethylamine, oxidize trimethylamine, dimethylamine, formaldehyde and formate; only bacterium 5B1 and Ps. 3A2 oxidize trimethylamine N-oxide; only bacterium 4B6 does not oxidize methylamine. 3. Cell-free extracts of trimethylamine-grown bacteria 4B6 and C2A1 contain a trimethylamine dehydrogenase that requires phenazine methosulphate as primary hydrogen acceptor, and evidence is presented that this enzyme is important for the growth of bacterium 4B6 on trimethylamine. 4. Cell-free extracts of eight facultative methylotrophs, including bacterium 5B1 and Ps. 3A2, do not contain trimethylamine dehydrogenase but contain instead a trimethylamine monooxygenase and trimethylamine N-oxide demethylase. It is concluded that two different pathways for the oxidation of trimethylamine occur amongst the isolates. PMID:4722893

  4. Men as caregivers: reciprocal relationships or obligation?

    PubMed

    Neufeld, A; Harrison, M J

    1998-11-01

    This study explored reciprocity in the relationships of men caregivers of cognitively impaired older adults. Reciprocity is a dimension of social support that is important in caregivers' ability to sustain supportive relationships. Equity theory predicts that inequitable (non-reciprocal) exchanges will result in termination of relationships. The objective of the study was to identify the context in which reciprocity was present or absent, the characteristics of reciprocity in caregivers' relationships with the care recipient, family and friends, and the men's feelings about reciprocal social support during caregiving. Twenty-two men caregivers were interviewed three times over 18 months. Study findings were confirmed in a focus group discussion with seven caregivers. Three variations in reciprocity in the men's relationship with the care recipient were identified: waived reciprocity, generalized reciprocity and constructed reciprocity. Those experiencing constructed or generalized reciprocity described positive feelings, whereas men identifying waived reciprocity described either positive or negative feelings. When reciprocity was absent the men described giving care on the basis of obligation with either mixed or negative feelings. Reciprocity in relationships with friends and family is also described. The study findings support the assumptions of equity theory about reciprocity; however, perceptions of obligation may be better understood in the context of the principles of justice and caring. PMID:9840867

  5. Functional Transfer of Salmonella Pathogenicity Island 2 to Salmonella bongori and Escherichia coli

    Microsoft Academic Search

    Imke Hansen-Wester; Dipshikha Chakravortty; Michael Hensel

    2004-01-01

    The type III secretion system (T3SS) encoded by the Salmonella pathogenicity island 2 (SPI2) has a central role in systemic infections by Salmonella enterica and for the intracellular phenotype. Intracellular S. enterica uses the SPI2-encoded T3SS to translocate a set of effector proteins into the host cell, which modify host cell functions, enabling intracellular survival and replication of the bacteria.

  6. Mechanisms of Borrelia burgdorferi internalization and intracellular innate immune signaling

    PubMed Central

    Petnicki-Ocwieja, Tanja; Kern, Aurelie

    2014-01-01

    Lyme disease is a long-term infection whose most severe pathology is characterized by inflammatory arthritis of the lower bearing joints, carditis, and neuropathy. The inflammatory cascades are initiated through the early recognition of invading Borrelia burgdorferi spirochetes by cells of the innate immune response, such as neutrophils and macrophage. B. burgdorferi does not have an intracellular niche and thus much research has focused on immune pathways activated by pathogen recognition molecules at the cell surface, such as the Toll-like receptors (TLRs). However, in recent years, studies have shown that internalization of the bacterium by host cells is an important component of the defense machinery in response to B. burgdorferi. Upon internalization, B. burgdorferi is trafficked through an endo/lysosomal pathway resulting in the activation of a number of intracellular pathogen recognition receptors including TLRs and Nod-like receptors (NLRs). Here we will review the innate immune molecules that participate in both cell surface and intracellular immune activation by B. burgdorferi. PMID:25566512

  7. Single-stranded DNA Plant Pathogens in Eilat

    Microsoft Academic Search

    Barbara Hohn; Thomas Hohn

    2006-01-01

    An international conference on ``Inter- and Intracellular Dynamics of ssDNA Plant Pathogens: Implications for Improving Resistance''\\u000a was sponsored by the United States-Israel Binational Agricultural Research and Deveoplment Fund (BARD) and organized in Eilat,\\u000a Israel in November 2005. The topic of this meeting was single-stranded plant pathogens, their inter- as well as intra-cellular\\u000a dynamics and their implications for improving resistance. Most

  8. Molecular basis of host specificity in human pathogenic bacteria

    PubMed Central

    Pan, Xiaolei; Yang, Yang; Zhang, Jing-Ren

    2014-01-01

    Pathogenic bacteria display various levels of host specificity or tropism. While many bacteria can infect a wide range of hosts, certain bacteria have strict host selectivity for humans as obligate human pathogens. Understanding the genetic and molecular basis of host specificity in pathogenic bacteria is important for understanding pathogenic mechanisms, developing better animal models and designing new strategies and therapeutics for the control of microbial diseases. The molecular mechanisms of bacterial host specificity are much less understood than those of viral pathogens, in part due to the complexity of the molecular composition and cellular structure of bacterial cells. However, important progress has been made in identifying and characterizing molecular determinants of bacterial host specificity in the last two decades. It is now clear that the host specificity of bacterial pathogens is determined by multiple molecular interactions between the pathogens and their hosts. Furthermore, certain basic principles regarding the host specificity of bacterial pathogens have emerged from the existing literature. This review focuses on selected human pathogenic bacteria and our current understanding of their host specificity. PMID:26038515

  9. Intracellular Demography and the Dynamics of Salmonella enterica Infections

    PubMed Central

    Sheppard, Mark; Grant, Andrew J; Maskell, Duncan J; Grenfell, Bryan T; Mastroeni, Pietro

    2006-01-01

    An understanding of within-host dynamics of pathogen interactions with eukaryotic cells can shape the development of effective preventive measures and drug regimes. Such investigations have been hampered by the difficulty of identifying and observing directly, within live tissues, the multiple key variables that underlay infection processes. Fluorescence microscopy data on intracellular distributions of Salmonella enterica serovar Typhimurium (S. Typhimurium) show that, while the number of infected cells increases with time, the distribution of bacteria between cells is stationary (though highly skewed). Here, we report a simple model framework for the intensity of intracellular infection that links the quasi-stationary distribution of bacteria to bacterial and cellular demography. This enables us to reject the hypothesis that the skewed distribution is generated by intrinsic cellular heterogeneities, and to derive specific predictions on the within-cell dynamics of Salmonella division and host-cell lysis. For within-cell pathogens in general, we show that within-cell dynamics have implications across pathogen dynamics, evolution, and control, and we develop novel generic guidelines for the design of antibacterial combination therapies and the management of antibiotic resistance. PMID:17048989

  10. Deciphering the Intracellular Fate of Propionibacterium acnes in Macrophages

    PubMed Central

    Fischer, Natalie; Mak, Tim N.; Shinohara, Debika Biswal; Sfanos, Karen S.; Meyer, Thomas F.

    2013-01-01

    Propionibacterium acnes is a Gram-positive bacterium that colonizes various niches of the human body, particularly the sebaceous follicles of the skin. Over the last years a role of this common skin bacterium as an opportunistic pathogen has been explored. Persistence of P. acnes in host tissue has been associated with chronic inflammation and disease development, for example, in prostate pathologies. This study investigated the intracellular fate of P. acnes in macrophages after phagocytosis. In a mouse model of P. acnes-induced chronic prostatic inflammation, the bacterium could be detected in prostate-infiltrating macrophages at 2 weeks postinfection. Further studies performed in the human macrophage cell line THP-1 revealed intracellular survival and persistence of P. acnes but no intracellular replication or escape from the host cell. Confocal analyses of phagosome acidification and maturation were performed. Acidification of P. acnes-containing phagosomes was observed at 6 h postinfection but then lost again, indicative of cytosolic escape of P. acnes or intraphagosomal pH neutralization. No colocalization with the lysosomal markers LAMP1 and cathepsin D was observed, implying that the P. acnes-containing phagosome does not fuse with lysosomes. Our findings give first insights into the intracellular fate of P. acnes; its persistency is likely to be important for the development of P. acnes-associated inflammatory diseases. PMID:23862148

  11. Activity of 10 antimicrobial agents against intracellular Rhodococcus equi.

    PubMed

    Giguère, Steeve; Berghaus, Londa J; Lee, Elise A

    2015-08-01

    Studies with facultative intracellular bacterial pathogens have shown that evaluation of the bactericidal activity of antimicrobial agents against intracellular bacteria is more closely associated with in vivo efficacy than traditional in vitro susceptibility testing. The objective of this study was to determine the relative activity of 10 antimicrobial agents against intracellular Rhodococcus equi. Equine monocyte-derived macrophages were infected with virulent R. equi and exposed to erythromycin, clarithromycin, azithromycin, rifampin, ceftiofur, gentamicin, enrofloxacin, vancomycin, imipenem, or doxycycline at concentrations achievable in plasma at clinically recommended dosages in foals. The number of intracellular R. equi was determined 48h after infection by counting colony forming units (CFUs). The number of R. equi CFUs in untreated control wells were significantly higher than those of monolayers treated with antimicrobial agents. Numbers of R. equi were significantly lower in monolayers treated with enrofloxacin followed by those treated with gentamicin, and vancomycin, when compared to monolayers treated with other antimicrobial agents. Numbers of R. equi in monolayers treated with doxycycline were significantly higher than those of monolayers treated with other antimicrobial agents. Differences in R. equi CFUs between monolayers treated with other antimicrobial agents were not statistically significant. Enrofloxacin, gentamicin, and vancomycin are the most active drugs in equine monocyte-derived macrophages infected with R. equi. Additional studies will be needed to determine if these findings correlate with in vivo efficacy. PMID:26051479

  12. Mitochondrial dysfunction and intracellular calcium dysregulation in ALS

    PubMed Central

    Kawamata, Hibiki; Manfredi, Giovanni

    2010-01-01

    Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder that affects the aging population. A progressive loss of motor neurons in the spinal cord and brain leads to muscle paralysis and death. As in other common neurodegenerative diseases, aging-related mitochondrial dysfunction is increasingly being considered among the pathogenic factors. Mitochondria are critical for cell survival: they provide energy to the cell, buffer intracellular calcium, and regulate apoptotic cell death. Whether mitochondrial abnormalities are a trigger or a consequence of the neurodegenerative process and the mechanisms whereby mitochondrial dysfunction contributes to disease are not clear yet. Calcium homeostasis is a major function of mitochondria in neurons, and there is ample evidence that intracellular calcium is dysregulated in ALS. The impact of mitochondrial dysfunction on intracellular calcium homeostasis and its role in motor neuron demise are intriguing issues that warrants in depth discussion. Clearly, unraveling the causal relationship between mitochondrial dysfunction, calcium dysregulation, and neuronal death is critical for the understanding of ALS pathogenesis. In this review, we will outline the current knowledge of various aspects of mitochondrial dysfunction in ALS, with a special emphasis on the role of these abnormalities on intracellular calcium handling. PMID:20493207

  13. Manganese homeostasis and utilization in pathogenic bacteria.

    PubMed

    Juttukonda, Lillian J; Skaar, Eric P

    2015-07-01

    Manganese (Mn) is a required cofactor for all forms of life. Given the importance of Mn to bacteria, the host has devised strategies to sequester Mn from invaders. In the macrophage phagosome, NRAMP1 removes Mn and other essential metals to starve intracellular pathogens; in the extracellular space, calprotectin chelates Mn and Zn. Calprotectin-mediated Mn sequestration is a newly appreciated host defense mechanism, and recent findings are highlighted herein. In order to acquire Mn when extracellular concentrations are low, bacteria have evolved efficient Mn acquisition systems that are under elegant transcriptional control. To counteract Mn overload, some bacteria possess Mn-specific export systems that are important in vivo, presumably for control of intracellular Mn levels. Mn transporters, their transcriptional regulators and some Mn-requiring enzymes are necessary for virulence of certain bacterial pathogens, as revealed by animal models of infection. Furthermore, Mn is an important facet of the cellular response to oxidative stress, a host antibacterial strategy. The battle for Mn between host and pathogen is now appreciated to be a major determinant of the outcome of infection. In this MicroReview, the contribution of Mn to the host-pathogen interaction is reviewed, and key questions are proposed for future study. PMID:25898914

  14. Utilities` ``obligation to serve`` under deregulation

    SciTech Connect

    Alexander, C.B.

    1997-02-01

    The utility no longer has protected status, and the traditional franchise concept is under attack. Exclusive rights once conveyed to the utilities are being denied and not just in the area of gas sales. Exclusive rights once conveyed to utilities will be denied in more areas. State by state, the utilities` franchise is being examined to see which, if any, of its provisions are necessary in a deregulated environment. Can the free market provide everything that`s been provided for many years under monopolistic arrangements? Some of the most critical and difficult of these provisions concern the obligation to serve, which utilities, in most states, have assumed as part of their franchise agreement. Regulators, courts, utilities, marketers and others are busy sorting through these issues, but resolution could take years. The paper discusses deregulation, universal service fee, representation without taxation, suppliers and marketer restrictions.

  15. [Dissemination of research--a neglected obligation].

    PubMed

    Nylenna, Magne; Hansen, Arild Skaug; Storeng, Anne Britt; Westin, Steinar

    2004-08-26

    In contrast to research and teaching duties, the obligation to disseminate research results to the general public is poorly described and not lived up to in academic medicine. At the Norwegian University of Science and Technology's Faculty of Medicine, an interdisciplinary group met with academics to discuss and identify means for improvements. The academics reported positive attitudes to popularising and communicating their findings. Dissemination of research as a working area was, however, characterised as fragmented, incidental and too much dependent on individual enthusiasm. The most important initiatives in order to achieve better dissemination were said to be the following: more and better training in popularization and dealing with the media; development of an infrastructure for dissemination at a decentralised institutional level (defined responsibility, routines etc.); and encouragement of good presentations by making dissemination of research meritorious. PMID:15334120

  16. Should Child Support Obligations Continue for Children Attending College?

    Microsoft Academic Search

    Jason D. Hans

    2008-01-01

    Beliefs regarding nonresidential parents' obligation to assist with college expenses were examined using a factorial vignette design with a random sample of 407 participants. Obligations to assist continue providing child support for children beyond the age of majority were contingent upon children attending college. However, only 52% of respondents believed that the nonresidential parent should continue paying child support for

  17. Deconfounding Distance Effects in Judgments of Moral Obligation

    ERIC Educational Resources Information Center

    Nagel, Jonas; Waldmann, Michael R.

    2013-01-01

    A heavily disputed question of moral philosophy is whether spatial distance between agent and victim is normatively relevant for the degree of obligation to help strangers in need. In this research, we focus on the associated descriptive question whether increased distance does in fact reduce individuals' sense of helping obligation. One problem…

  18. Preservation of proof obligations for hybrid verification methods Gilles Barthe

    E-print Network

    Paris-Sud XI, Université de

    Preservation of proof obligations for hybrid verification methods Gilles Barthe IMDEA Software generation, compilation preserves proof obligations and therefore it is possible to transfer evidence from source to compiled programs. Our result relies on the preservation of the solutions of analysis

  19. The Legionella pneumophila GacA homolog (LetA) is involved in the regulation of icm virulence genes and is required for intracellular multiplication in Acanthamoeba castellanii

    Microsoft Academic Search

    Ohad Gal-Mor; Gil Segal

    2003-01-01

    Legionella pneumophila, the causative agent of legionnaires' disease, is a broad-host-range facultative intracellular pathogen. Thus far, 24 genes (icm\\/dot genes) required for L. pneumophila intracellular growth, have been discovered. In this study, a deletion substitution was constructed in the L. pneumophila homolog of the gacA response regulator (letA) and its involvement in L. pneumophila pathogenicity and icm\\/dot gene expression was

  20. Phenotypic Mutants of the Intracellular Actinomycete Rhodococcusequi Created by In Vivo Himar1 Transposon Mutagenesis

    Microsoft Academic Search

    Joseph Ashour; Mary K. Hondalus

    2003-01-01

    Rhodococcus equi is a facultative intracellular opportunistic pathogen of immunocompromised people and a major cause of pneumonia in young horses. An effective live attenuated vaccine would be extremely useful in the prevention of R. equi disease in horses. Toward that end, we have developed an efficient transposon mutagenesis system that makes use of a Himar1 minitransposon delivered by a conditionally

  1. Analysis of Ten Brucella Genomes Reveals Evidence for Horizontal Gene Transfer Despite a Preferred Intracellular Lifestyle

    Microsoft Academic Search

    Alice R. Wattam; Kelly P. Williams; Eric E. Snyder; Nalvo F. Almeida; Maulik Shukla; A. W. Dickerman; O. R. Crasta; R. Kenyon; J. Lu; J. M. Shallom; H. Yoo; T. A. Ficht; R. M. Tsolis; C. Munk; R. Tapia; C. S. Han; J. C. Detter; D. Bruce; T. S. Brettin; Bruno W. Sobral; Stephen M. Boyle; Joao C. Setubal

    2009-01-01

    The facultative intracellular bacterial pathogen Brucella infects a wide range of warm-blooded land and marine vertebrates and causes brucellosis. Currently, there are nine recognized Brucella species based on host preferences and phenotypic differences. The availability of 10 different genomes consisting of two chromosomes and representing six of the species allowed for a detailed comparison among themselves and relatives in the

  2. Innate and adaptive immune responses to an intracellular bacterium, Francisella tularensis live vaccine strain

    Microsoft Academic Search

    Karen L. Elkins

    2003-01-01

    The immune response to intracellular bacterium, Francisella tularensis, which causes tularemia and is proposed to be a potential bioterrorism pathogen, has been studied in mice using the attenuated live vaccine strain (LVS). Here we review this infection model, which provides a convenient means of studying protective immune mechanisms not only for Francisella, but also for the large and important class

  3. A Lack of Parasitic Reduction in the Obligate Parasitic Green Alga Helicosporidium

    PubMed Central

    Pombert, Jean-François; Blouin, Nicolas Achille; Lane, Chris; Boucias, Drion; Keeling, Patrick J.

    2014-01-01

    The evolution of an obligate parasitic lifestyle is often associated with genomic reduction, in particular with the loss of functions associated with increasing host-dependence. This is evident in many parasites, but perhaps the most extreme transitions are from free-living autotrophic algae to obligate parasites. The best-known examples of this are the apicomplexans such as Plasmodium, which evolved from algae with red secondary plastids. However, an analogous transition also took place independently in the Helicosporidia, where an obligate parasite of animals with an intracellular infection mechanism evolved from algae with green primary plastids. We characterised the nuclear genome of Helicosporidium to compare its transition to parasitism with that of apicomplexans. The Helicosporidium genome is small and compact, even by comparison with the relatively small genomes of the closely related green algae Chlorella and Coccomyxa, but at the functional level we find almost no evidence for reduction. Nearly all ancestral metabolic functions are retained, with the single major exception of photosynthesis, and even here reduction is not complete. The great majority of genes for light-harvesting complexes, photosystems, and pigment biosynthesis have been lost, but those for other photosynthesis-related functions, such as Calvin cycle, are retained. Rather than loss of whole function categories, the predominant reductive force in the Helicosporidium genome is a contraction of gene family complexity, but even here most losses affect families associated with genome maintenance and expression, not functions associated with host-dependence. Other gene families appear to have expanded in response to parasitism, in particular chitinases, including those predicted to digest the chitinous barriers of the insect host or remodel the cell wall of Helicosporidium. Overall, the Helicosporidium genome presents a fascinating picture of the early stages of a transition from free-living autotroph to parasitic heterotroph where host-independence has been unexpectedly preserved. PMID:24809511

  4. Polyamines are implicated in the emergence of the embryo from obligate diapause.

    PubMed

    Lefèvre, Pavine L C; Palin, Marie-France; Chen, Gary; Turecki, Gustavo; Murphy, Bruce D

    2011-04-01

    Embryonic diapause is a poorly understood phenomenon of reversible arrest of embryo development prior to implantation. In many carnivores, such as the mink (Neovison vison), obligate diapause characterizes each gestation. Embryo reactivation is controlled by the uterus by mechanisms that remain elusive. Because polyamines are essential regulators of cell proliferation and growth, it was hypothesized that they trigger embryo reactivation. To test this, mated mink females were treated with ?-difluoromethylornithine, an inhibitor of ornithine decarboxylase 1, the rate-limiting enzyme in polyamine biosynthesis, or saline as a control during the first 5 d of reactivation. This treatment induced polyamine deprivation with the consequence of rearrest in embryo cell proliferation. A mink trophoblast cell line in vitro subjected to ?-difluoromethylornithine treatment likewise displayed an arrest in cell proliferation, morphological changes, and intracellular translocation of ornithine decarboxylase 1 protein. The arrest in embryo development deferred implantation for a period consistent with the length of treatment. Successful implantation and parturition ensued. We conclude that polyamine deprivation brought about a reversible rearrest of embryo development, which returned the mink embryo to diapause and induced a second delay in embryo implantation. The results are the first demonstration of a factor essential to reactivation of embryos in obligate diapause. PMID:21303959

  5. The Evolution of Genomic Instability in the Obligate Endosymbionts of Whiteflies

    PubMed Central

    Sloan, Daniel B.; Moran, Nancy A.

    2013-01-01

    Many insects depend on ancient associations with intracellular bacteria to perform essential metabolic functions. These endosymbionts exhibit striking examples of convergence in genome architecture, including a high degree of structural stability that is not typical of their free-living counterparts. However, the recently sequenced genome of the obligate whitefly endosymbiont Portiera revealed features that distinguish it from other ancient insect associates, such as a low gene density and the presence of perfectly duplicated sequences. Here, we report the comparative analysis of Portiera genome sequences both within and between host species. In one whitefly lineage (Bemisia tabaci), we identify large-scale structural polymorphisms in the Portiera genome that exist even within individual insects. This variation is likely mediated by recombination across identical repeats that are maintained by gene conversion. The complete Portiera genome sequence from a distantly related whitefly host (Trialeurodes vaporarium) confirms a history of extensive genome rearrangement in this ancient endosymbiont. Using gene-order-based phylogenetic analysis, we show that the majority of rearrangements have occurred in the B. tabaci lineage, coinciding with an increase in the rate of nucleotide substitutions, a proliferation of short tandem repeats (microsatellites) in intergenic regions, and the loss of many widely conserved genes involved in DNA replication, recombination, and repair. These results indicate that the loss of recombinational machinery is unlikely to be the cause of the extreme structural conservation that is generally observed in obligate endosymbiont genomes and that large, repetitive intergenic regions are an important substrate for genomic rearrangements. PMID:23542079

  6. Host cell-free growth of the Q fever bacterium Coxiella burnetii

    Microsoft Academic Search

    Anders Omsland; Diane C. Cockrell; Dale Howe; Elizabeth R. Fischer; Kimmo Virtaneva; Daniel E. Sturdevant; Stephen F. Porcella; Robert A. Heinzen

    2009-01-01

    The inability to propagate obligate intracellular pathogens under axenic (host cell-free) culture conditions imposes severe experimental constraints that have negatively impacted progress in understanding pathogen virulence and disease mechanisms. Coxiella burnetii, the causative agent of human Q (Query) fever, is an obligate intracellular bacterial pathogen that replicates exclusively in an acidified, lysosome-like vacuole. To define conditions that support C. burnetii

  7. Linking the Transcriptional Profiles and the Physiological States of Mycobacterium tuberculosis during an Extended Intracellular Infection

    PubMed Central

    Rohde, Kyle H.; Veiga, Diogo F. T.; Caldwell, Shannon; Balázsi, Gábor; Russell, David G.

    2012-01-01

    Intracellular pathogens such as Mycobacterium tuberculosis have evolved strategies for coping with the pressures encountered inside host cells. The ability to coordinate global gene expression in response to environmental and internal cues is one key to their success. Prolonged survival and replication within macrophages, a key virulence trait of M. tuberculosis, requires dynamic adaptation to diverse and changing conditions within its phagosomal niche. However, the physiological adaptations during the different phases of this infection process remain poorly understood. To address this knowledge gap, we have developed a multi-tiered approach to define the temporal patterns of gene expression in M. tuberculosis in a macrophage infection model that extends from infection, through intracellular adaptation, to the establishment of a productive infection. Using a clock plasmid to measure intracellular replication and death rates over a 14-day infection and electron microscopy to define bacterial integrity, we observed an initial period of rapid replication coupled with a high death rate. This was followed by period of slowed growth and enhanced intracellular survival, leading finally to an extended period of net growth. The transcriptional profiles of M. tuberculosis reflect these physiological transitions as the bacterium adapts to conditions within its host cell. Finally, analysis with a Transcriptional Regulatory Network model revealed linked genetic networks whereby M. tuberculosis coordinates global gene expression during intracellular survival. The integration of molecular and cellular biology together with transcriptional profiling and systems analysis offers unique insights into the host-driven responses of intracellular pathogens such as M. tuberculosis. PMID:22737072

  8. Intracellularly Induced Cyclophilins Play an Important Role in Stress Adaptation and Virulence of Brucella abortus

    PubMed Central

    García Fernández, Lucía; DelVecchio, Vito G.; Briones, Gabriel

    2013-01-01

    Brucella is an intracellular bacterial pathogen that causes the worldwide zoonotic disease brucellosis. Brucella virulence relies on its ability to transition to an intracellular lifestyle within host cells. Thus, this pathogen must sense its intracellular localization and then reprogram gene expression for survival within the host cell. A comparative proteomic investigation was performed to identify differentially expressed proteins potentially relevant for Brucella intracellular adaptation. Two proteins identified as cyclophilins (CypA and CypB) were overexpressed in the intracellular environment of the host cell in comparison to laboratory-grown Brucella. To define the potential role of cyclophilins in Brucella virulence, a double-deletion mutant was constructed and its resulting phenotype was characterized. The Brucella abortus ?cypAB mutant displayed increased sensitivity to environmental stressors, such as oxidative stress, pH, and detergents. In addition, the B. abortus ?cypAB mutant strain had a reduced growth rate at lower temperature, a phenotype associated with defective expression of cyclophilins in other microorganisms. The B. abortus ?cypAB mutant also displays reduced virulence in BALB/c mice and defective intracellular survival in HeLa cells. These findings suggest that cyclophilins are important for Brucella virulence and survival in the host cells. PMID:23230297

  9. 20 CFR 655.20 - Assurances and obligations of H-2B employers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Assurances and obligations of H-2B employers. 655.20 Section 655.20 Employees' Benefits EMPLOYMENT AND TRAINING...States (H-2B Workers) Assurances and Obligations § 655.20 Assurances and obligations of H-2B...

  10. 20 CFR 655.20 - Assurances and obligations of H-2B employers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Assurances and obligations of H-2B employers. 655.20 Section 655.20 Employees' Benefits EMPLOYMENT AND TRAINING...States (H-2B Workers) Assurances and Obligations § 655.20 Assurances and obligations of H-2B...

  11. 31 CFR 225.9 - Return of Government obligations to obligor.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Return of Government obligations to obligor. 225... ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.9 Return of Government obligations to obligor....

  12. 31 CFR 225.9 - Return of Government obligations to obligor.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Return of Government obligations to obligor. 225... ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.9 Return of Government obligations to obligor....

  13. 31 CFR 225.9 - Return of Government obligations to obligor.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Return of Government obligations to obligor. 225... ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.9 Return of Government obligations to obligor....

  14. 31 CFR 225.9 - Return of Government obligations to obligor.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Return of Government obligations to obligor. 225... ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.9 Return of Government obligations to obligor....

  15. 12 CFR 987.8 - Additional requirements; notice of attachment for Book-entry consolidated obligations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...requirements; notice of attachment for Book-entry consolidated obligations. 987...HOUSING FINANCE BOARD OFFICE OF FINANCE BOOK-ENTRY PROCEDURE FOR CONSOLIDATED OBLIGATIONS...requirements; notice of attachment for Book-entry consolidated obligations....

  16. 12 CFR 1270.18 - Additional requirements; notice of attachment for Book-entry consolidated obligations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...requirements; notice of attachment for Book-entry consolidated obligations. 1270...FEDERAL HOME LOAN BANKS LIABILITIES Book-Entry Procedure for Consolidated Obligations...requirements; notice of attachment for Book-entry consolidated obligations....

  17. 12 CFR 1270.18 - Additional requirements; notice of attachment for Book-entry consolidated obligations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...requirements; notice of attachment for Book-entry consolidated obligations. 1270...FEDERAL HOME LOAN BANKS LIABILITIES Book-Entry Procedure for Consolidated Obligations...requirements; notice of attachment for Book-entry consolidated obligations....

  18. 12 CFR 1270.18 - Additional requirements; notice of attachment for Book-entry consolidated obligations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...requirements; notice of attachment for Book-entry consolidated obligations. 1270...FEDERAL HOME LOAN BANKS LIABILITIES Book-Entry Procedure for Consolidated Obligations...requirements; notice of attachment for Book-entry consolidated obligations....

  19. 12 CFR 987.8 - Additional requirements; notice of attachment for Book-entry consolidated obligations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...requirements; notice of attachment for Book-entry consolidated obligations. 987...HOUSING FINANCE BOARD OFFICE OF FINANCE BOOK-ENTRY PROCEDURE FOR CONSOLIDATED OBLIGATIONS...requirements; notice of attachment for Book-entry consolidated obligations....

  20. Host-pathogen diversity in a wild system: Chondrilla juncea – Puccinia chondrillina

    Microsoft Academic Search

    C. Espiau; D. Riviere; J. J. Burdon; S. Gartner; B. Daclinat; S. Hasan; P. Chaboudez

    1997-01-01

    The resistance structure of a Turkish population of the clonal, apomictic composite Chondrilla juncea and the pathotypic structure of a co-occurring population of its obligate rust pathogen, Puccinia chondrillina, was determined by sequential inoculation of 19 host lines with 15 pathogen isolates each derived from single pustules collected\\u000a from separate plants among the host population. The resultant matrix of resistant

  1. he molecular basis of the pathogenicity of in-

    E-print Network

    Ewbank, Jonathan

    to demonstrate that different genes act as virulence factors in the two pathologies. Significantly, the majority viruses such as HIV and intracellular bacterial pathogens such as Listeria and Salmonella, restricts mutants that exhib- ited reduced virulence in C. elegans, Ausubel and col- leagues have been able

  2. Salmonella pathogenicity islands encoding type III secretion systems

    Microsoft Academic Search

    Imke Hansen-Wester; Michael Hensel

    2001-01-01

    Salmonella enterica harbours two Salmonella pathogenicity islands (SPIs) each encoding a type III secretion system for virulence proteins. SPI1 is required for invasion, while systemic infections and intracellular accumulation of Salmonella are dependent on SPI2 function. This review will describe and compare the genetic organisation, evolution, regulation and molecular functions of SPI1 and SPI2.

  3. How do adaptive immune systems control pathogens while avoiding

    E-print Network

    Bergstrom, Carl T.

    are met by two immune systems, the intracellular RNA interference system and the vertebrate CD8 THow do adaptive immune systems control pathogens while avoiding autoimmunity? Carl T. Bergstrom1 of Biology, Emory University, Atlanta, GA 30329, USA Immune systems face a daunting control challenge

  4. Comparison of PCR, Immunofluorescence Assay, and Pathogen Isolation for Diagnosis of Q Fever in Humans with Spontaneous Abortions

    Microsoft Academic Search

    V. M. Vaidya; S. V. S. Malik; Simranpreet Kaur; Satish Kumar; S. B. Barbuddhe

    2008-01-01

    Coxiella burnetii, an obligate intracellular parasite with a worldwide distribution, is the causative agent of Q fever in humans. We tested a total of 368 samples (placental bits, genital swabs, fecal swabs, and urine and serum samples) collected from women (n 74) with spontaneous abortions for C. burnetii by a PCR assay targeting IS1111, the repetitive transposon-like region of C.

  5. The destructive citrus pathogen, ‘Candidatus Liberibacter asiaticus’ encodes a functional flagellin characteristic of a pathogen-associated molecular pattern

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is presently the most devastating citrus disease worldwide. As an intracellular plant pathogen and insect symbiont, the HLB bacterium, ‘Candidatus Liberibacter asiaticus’ (Las) retains the entire flagellum-encoding gene cluster in its significantly reduced genome. Las encodes a...

  6. Temporal dynamics of outcrossing and host mortality rates in host-pathogen experimental coevolution.

    PubMed

    Morran, Levi T; Parrish, Raymond C; Gelarden, Ian A; Lively, Curtis M

    2013-07-01

    Cross-fertilization is predicted to facilitate the short-term response and the long-term persistence of host populations engaged in antagonistic coevolutionary interactions. Consistent with this idea, our previous work has shown that coevolving bacterial pathogens (Serratia marcescens) can drive obligately selfing hosts (Caenorhabditis elegans) to extinction, whereas the obligately outcrossing and partially outcrossing populations persisted. We focused the present study on the partially outcrossing (mixed mating) and obligately outcrossing hosts, and analyzed the changes in the host resistance/avoidance (and pathogen infectivity) over time. We found that host mortality rates increased in the mixed mating populations over the first 10 generations of coevolution when outcrossing rates were initially low. However, mortality rates decreased after elevated outcrossing rates evolved during the experiment. In contrast, host mortality rates decreased in the obligately outcrossing populations during the first 10 generations of coevolution, and remained low throughout the experiment. Therefore, predominant selfing reduced the ability of the hosts to respond to coevolving pathogens compared to outcrossing hosts. Thus, we found that host-pathogen coevolution can generate rapid evolutionary change, and that host mating system can influence the outcome of coevolution at a fine temporal scale. PMID:23815644

  7. Emerging intracellular receptors for hemorrhagic fever viruses.

    PubMed

    Jae, Lucas T; Brummelkamp, Thijn R

    2015-07-01

    Ebola virus and Lassa virus belong to different virus families that can cause viral hemorrhagic fever, a life-threatening disease in humans with limited treatment options. To infect a target cell, Ebola and Lassa viruses engage receptors at the cell surface and are subsequently shuttled into the endosomal compartment. Upon arrival in late endosomes/lysosomes, the viruses trigger membrane fusion to release their genome into the cytoplasm. Although contact sites at the cell surface were recognized for Ebola virus and Lassa virus, it was postulated that Ebola virus requires a critical receptor inside the cell. Recent screens for host factors identified such internal receptors for both viruses: Niemann-Pick disease type C1 protein (NPC1) for Ebola virus and lysosome-associated membrane protein 1 (LAMP1) for Lassa virus. A cellular trigger is needed to permit binding of the viral envelope protein to these intracellular receptors. This 'receptor switch' represents a previously unnoticed step in virus entry with implications for host-pathogen interactions and viral tropism. PMID:26004032

  8. Comparative Analysis of Chlamydia psittaci Genomes Reveals the Recent Emergence of a Pathogenic Lineage with a Broad Host Range

    PubMed Central

    Read, Timothy D.; Joseph, Sandeep J.; Didelot, Xavier; Liang, Brooke; Patel, Lisa; Dean, Deborah

    2013-01-01

    ABSTRACT Chlamydia psittaci is an obligate intracellular bacterium. Interest in Chlamydia stems from its high degree of virulence as an intestinal and pulmonary pathogen across a broad range of animals, including humans. C. psittaci human pulmonary infections, referred to as psittacosis, can be life-threatening, which is why the organism was developed as a bioweapon in the 20th century and is listed as a CDC biothreat agent. One remarkable recent result from comparative genomics is the finding of frequent homologous recombination across the genome of the sexually transmitted and trachoma pathogen Chlamydia trachomatis. We sought to determine if similar evolutionary dynamics occurred in C. psittaci. We analyzed 20 C. psittaci genomes from diverse strains representing the nine known serotypes of the organism as well as infections in a range of birds and mammals, including humans. Genome annotation revealed a core genome in all strains of 911 genes. Our analyses showed that C. psittaci has a history of frequently switching hosts and undergoing recombination more often than C. trachomatis. Evolutionary history reconstructions showed genome-wide homologous recombination and evidence of whole-plasmid exchange. Tracking the origins of recombinant segments revealed that some strains have imported DNA from as-yet-unsampled or -unsequenced C. psittaci lineages or other Chlamydiaceae species. Three ancestral populations of C. psittaci were predicted, explaining the current population structure. Molecular clock analysis found that certain strains are part of a clonal epidemic expansion likely introduced into North America by South American bird traders, suggesting that psittacosis is a recently emerged disease originating in New World parrots. PMID:23532978

  9. Effector-triggered defence against apoplastic fungal pathogens.

    PubMed

    Stotz, Henrik U; Mitrousia, Georgia K; de Wit, Pierre J G M; Fitt, Bruce D L

    2014-08-01

    R gene-mediated host resistance against apoplastic fungal pathogens is not adequately explained by the terms pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) or effector-triggered immunity (ETI). Therefore, it is proposed that this type of resistance is termed 'effector-triggered defence' (ETD). Unlike PTI and ETI, ETD is mediated by R genes encoding cell surface-localised receptor-like proteins (RLPs) that engage the receptor-like kinase SOBIR1. In contrast to this extracellular recognition, ETI is initiated by intracellular detection of pathogen effectors. ETI is usually associated with fast, hypersensitive host cell death, whereas ETD often triggers host cell death only after an elapsed period of endophytic pathogen growth. In this opinion, we focus on ETD responses against foliar fungal pathogens of crops. PMID:24856287

  10. Effector-triggered defence against apoplastic fungal pathogens

    PubMed Central

    Stotz, Henrik U.; Mitrousia, Georgia K.; de Wit, Pierre J.G.M.; Fitt, Bruce D.L.

    2014-01-01

    R gene-mediated host resistance against apoplastic fungal pathogens is not adequately explained by the terms pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) or effector-triggered immunity (ETI). Therefore, it is proposed that this type of resistance is termed ‘effector-triggered defence’ (ETD). Unlike PTI and ETI, ETD is mediated by R genes encoding cell surface-localised receptor-like proteins (RLPs) that engage the receptor-like kinase SOBIR1. In contrast to this extracellular recognition, ETI is initiated by intracellular detection of pathogen effectors. ETI is usually associated with fast, hypersensitive host cell death, whereas ETD often triggers host cell death only after an elapsed period of endophytic pathogen growth. In this opinion, we focus on ETD responses against foliar fungal pathogens of crops. PMID:24856287

  11. Cell-specific Activation of Nuclear Factor-k Bb y the Parasite Trypanosoma cruzi Promotes Resistance to Intracellular Infection

    Microsoft Academic Search

    Belinda S. Hall; Winnie Tam; Ranjan Sen; Miercio E. A. Pereira

    2000-01-01

    The transcription factor nuclear factor-kB (NF-kB) is central to the innate and acquired immune response to microbial pathogens, coordinating cellular responses to the presence of infection. Here we demonstrate a direct role for NF-kB activation in controlling intracellular infection in nonim- mune cells. Trypanosoma cruzi is an intracellular parasite of mammalian cells with a marked preference for infection of myocytes.

  12. Obligate Insect Endosymbionts Exhibit Increased Ortholog Length Variation and Loss of Large Accessory Proteins Concurrent with Genome Shrinkage

    PubMed Central

    Kenyon, Laura J.; Sabree, Zakee L.

    2014-01-01

    Extreme genome reduction has been observed in obligate intracellular insect mutualists and is an assumed consequence of fixed, long-term host isolation. Rapid accumulation of mutations and pseudogenization of genes no longer vital for an intracellular lifestyle, followed by deletion of many genes, are factors that lead to genome reduction. Size reductions in individual genes due to small-scale deletions have also been implicated in contributing to overall genome shrinkage. Conserved protein functional domains are expected to exhibit low tolerance for mutations and therefore remain relatively unchanged throughout protein length reduction while nondomain regions, presumably under less selective pressures, would shorten. This hypothesis was tested using orthologous protein sets from the Flavobacteriaceae (phylum: Bacteroidetes) and Enterobacteriaceae (subphylum: Gammaproteobacteria) families, each of which includes some of the smallest known genomes. Upon examination of protein, functional domain, and nondomain region lengths, we found that proteins were not uniformly shrinking with genome reduction, but instead increased length variability and variability was observed in both the functional domain and nondomain regions. Additionally, as complete gene loss also contributes to overall genome shrinkage, we found that the largest proteins in the proteomes of nonhost-restricted bacteroidetial and gammaproteobacterial species often were inferred to be involved in secondary metabolic processes, extracellular sensing, or of unknown function. These proteins were absent in the proteomes of obligate insect endosymbionts. Therefore, loss of genes encoding large proteins not required for host-restricted lifestyles in obligate endosymbiont proteomes likely contributes to extreme genome reduction to a greater degree than gene shrinkage. PMID:24671745

  13. Glochidioboside Kills Pathogenic Bacteria by Membrane Perturbation.

    PubMed

    Lee, Heejeong; Woo, Eun-Rhan; Lee, Dong Gun

    2015-07-01

    The aim of this study was to evaluate the antibacterial effects of glochidioboside and determine its mechanism of action. Glochidioboside has been reported to be isolated from some plants but the underlying biological properties have remained largely obscure until now. To identify the antibacterial activity of all biological properties, pathogenic bacteria susceptibility test was performed, and the result shows that the compound displays remarkable antibacterial activity against antibiotic-resistant bacteria not to mention general pathogen. To demonstrate membrane disruption and depolarization, SYTOX green and bis-(1,3-dibutylbarbituric acid) trimethine oxonol were used with Escherichia coli O157, and indicated that glochidioboside affected cytoplasmic membranes by permeabilization and depolarization, respectively. Calcein efflux was evident in a membrane model that encapsulated fluorescent dye, and supported the hypothesis of a membrane-active mechanism. To confirm the release of intracellular matrix owing to membrane damage, the movements of potassium ion were observed; the results indicated that the cells treated with glochidioboside leaked potassium ion, thus the damage induced by the compounds lead to leaking intracellular components. We propose that glochidioboside kills pathogenic bacteria via perturbation of integrity of the membrane. PMID:25820208

  14. PATHOGENS: VIEWS OF EPA'S PATHOGEN EQUIVALENCY COMMITTEE

    EPA Science Inventory

    This presentation reviews the pathogenic microorganisms that may be found in municipal sewage sludge and the commonly employed Class A and B processes for controlling pathogens. It notes how extensively they are used and discusses issues and concerns with their application. Pre...

  15. Mast cell-orchestrated immunity to pathogens

    PubMed Central

    Abraham, Soman N.; St John, Ashley L.

    2015-01-01

    Although mast cells were discovered more than a century ago, their functions beyond their role in allergic responses remained elusive until recently. However, there is a growing appreciation that an important physiological function of these cells is the recognition of pathogens and modulation of appropriate immune responses. Because of their ability to instantly release several pro-inflammatory mediators from intracellular stores and their location at the host–environment interface, mast cells have been shown to be crucial for optimal immune responses during infection. Mast cells seem to exert these effects by altering the inflammatory environment after detection of a pathogen and by mobilizing various immune cells to the site of infection and to draining lymph nodes. Interestingly, the character and timing of these responses can vary depending on the type of pathogen stimulus, location of pathogen recognition and sensitization state of the responding mast cells. Recent studies using mast cell activators as effective vaccine adjuvants show the potential of harnessing these cells to confer protective immunity against microbial pathogens. PMID:20498670

  16. Differential regulation of host mRNA translation during obligate pathogen-plant interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Virus infection reprograms the plant messenger RNA (mRNA) transcriptome by activating or interfering with a variety of signaling pathways, but the effects on host mRNA translation have not been explored on a genome-wide scale. To address this issue, Arabidopsis thaliana mRNA transcripts were quantif...

  17. Comparative Genomics Suggests that the Fungal Pathogen Pneumocystis Is an Obligate Parasite

    E-print Network

    Alvarez, Nadir

    Pneumocystis carinii infecting rats, which is a well established experimental model of the disease. We. The proteome of the closely related yeast Schizosaccharomyces pombe was used as a control for the annotation for the management of patients susceptible to P. jirovecii infection given that the only source of infection would

  18. 22 CFR 231.07 - Fiscal Agent obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...Agent obligations. 231.07 Section 231.07 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ARAB REPUBLIC OF EGYPT LOAN GUARANTEES ISSUED UNDER THE EMERGENCY WARTIME SUPPLEMENTAL APPROPRIATIONS ACT OF 2003, PUBLIC LAW...

  19. 22 CFR 231.07 - Fiscal Agent obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Agent obligations. 231.07 Section 231.07 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ARAB REPUBLIC OF EGYPT LOAN GUARANTEES ISSUED UNDER THE EMERGENCY WARTIME SUPPLEMENTAL APPROPRIATIONS ACT OF 2003, PUBLIC LAW...

  20. 22 CFR 231.07 - Fiscal Agent obligations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...Agent obligations. 231.07 Section 231.07 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ARAB REPUBLIC OF EGYPT LOAN GUARANTEES ISSUED UNDER THE EMERGENCY WARTIME SUPPLEMENTAL APPROPRIATIONS ACT OF 2003, PUBLIC LAW...

  1. 22 CFR 231.07 - Fiscal Agent obligations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...Agent obligations. 231.07 Section 231.07 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ARAB REPUBLIC OF EGYPT LOAN GUARANTEES ISSUED UNDER THE EMERGENCY WARTIME SUPPLEMENTAL APPROPRIATIONS ACT OF 2003, PUBLIC LAW...

  2. 22 CFR 231.07 - Fiscal Agent obligations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...Agent obligations. 231.07 Section 231.07 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ARAB REPUBLIC OF EGYPT LOAN GUARANTEES ISSUED UNDER THE EMERGENCY WARTIME SUPPLEMENTAL APPROPRIATIONS ACT OF 2003, PUBLIC LAW...

  3. 22 CFR 232.07 - Fiscal agent obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...Fiscal agent obligations. 232.07 Section 232.07 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT REPUBLIC OF TUNISIA LOAN GUARANTEES ISSUED UNDER THE DEPARTMENT OF STATE, FOREIGN OPERATIONS, AND RELATED PROGRAMS APPROPRIATIONS ACT,...

  4. 22 CFR 232.07 - Fiscal agent obligations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...Fiscal agent obligations. 232.07 Section 232.07 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT REPUBLIC OF TUNISIA LOAN GUARANTEES ISSUED UNDER THE DEPARTMENT OF STATE, FOREIGN OPERATIONS, AND RELATED PROGRAMS APPROPRIATIONS ACT,...

  5. 48 CFR 243.204-70-4 - Limitations on obligations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CONTRACT MANAGEMENT CONTRACT MODIFICATIONS Change Orders 243.204-70-4 Limitations on obligations. (a) The Government shall not...

  6. 31 CFR 223.18 - Performance of agency obligations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...WITH THE UNITED STATES § 223.18 Performance of agency obligations. (a) Every company shall promptly honor its bonds naming the United States or one of its agencies or instrumentalities as obligee. If an agency's demand upon a company...

  7. 47 CFR 64.3001 - Obligation to transmit 911 calls.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Number § 64.3001 Obligation to transmit 911 calls. All telecommunications carriers shall transmit all 911 calls to a PSAP, to a designated statewide default answering point, or to an appropriate local emergency authority as set forth in §...

  8. 47 CFR 64.3001 - Obligation to transmit 911 calls.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Number § 64.3001 Obligation to transmit 911 calls. All telecommunications carriers shall transmit all 911 calls to a PSAP, to a designated statewide default answering point, or to an appropriate local emergency authority as set forth in §...

  9. 47 CFR 64.3001 - Obligation to transmit 911 calls.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Number § 64.3001 Obligation to transmit 911 calls. All telecommunications carriers shall transmit all 911 calls to a PSAP, to a designated statewide default answering point, or to an appropriate local emergency authority as set forth in §...

  10. 47 CFR 64.3001 - Obligation to transmit 911 calls.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Number § 64.3001 Obligation to transmit 911 calls. All telecommunications carriers shall transmit all 911 calls to a PSAP, to a designated statewide default answering point, or to an appropriate local emergency authority as set forth in §...

  11. 47 CFR 64.3001 - Obligation to transmit 911 calls.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Number § 64.3001 Obligation to transmit 911 calls. All telecommunications carriers shall transmit all 911 calls to a PSAP, to a designated statewide default answering point, or to an appropriate local emergency authority as set forth in §...

  12. 43 CFR 3162.2 - Drilling, producing, and drainage obligations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Interior 2 2012-10-01 2012-10-01 false Drilling, producing, and drainage obligations. 3162.2 Section...Requirements for Operating Rights Owners and Operators § 3162.2 Drilling, producing, and drainage...

  13. 43 CFR 3162.2 - Drilling, producing, and drainage obligations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Interior 2 2014-10-01 2014-10-01 false Drilling, producing, and drainage obligations. 3162.2 Section...Requirements for Operating Rights Owners and Operators § 3162.2 Drilling, producing, and drainage...

  14. 43 CFR 3162.2 - Drilling, producing, and drainage obligations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Interior 2 2011-10-01 2011-10-01 false Drilling, producing, and drainage obligations. 3162.2 Section...Requirements for Operating Rights Owners and Operators § 3162.2 Drilling, producing, and drainage...

  15. 43 CFR 3162.2 - Drilling, producing, and drainage obligations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Interior 2 2013-10-01 2013-10-01 false Drilling, producing, and drainage obligations. 3162.2 Section...Requirements for Operating Rights Owners and Operators § 3162.2 Drilling, producing, and drainage...

  16. 32 CFR 901.25 - Obligation of cadet appointment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Defense (Continued) DEPARTMENT OF THE AIR FORCE MILITARY TRAINING AND SCHOOLS APPOINTMENT TO THE UNITED STATES AIR...an oath of allegiance as a cadet normally assumes a military service obligation of not less than 6 years nor...

  17. 18 CFR 346.3 - Asset retirement obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...ENERGY REGULATIONS UNDER THE INTERSTATE COMMERCE ACT OIL PIPELINE COST-OF-SERVICE FILING REQUIREMENTS § 346.3 Asset...components related to asset retirement obligations that would impact the calculation of rate base, such as carrier property...

  18. 15 CFR 711.4 - Assistance in determining your obligations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...SECURITY, DEPARTMENT OF COMMERCE CHEMICAL WEAPONS CONVENTION REGULATIONS GENERAL...obligations. (a) Determining if your chemical is subject to declaration, reporting...assistance in determining if your chemical is classified as a Schedule...

  19. 29 CFR 1980.102 - Obligations and prohibited acts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...false Obligations and prohibited acts. 1980.102 Section 1980.102...COMPLAINTS UNDER SECTION 806 OF THE CORPORATE AND CRIMINAL FRAUD ACCOUNTABILITY ACT OF 2002, TITLE VIII OF THE SARBANES-OXLEY ACT OF 2002 Complaints,...

  20. 7 CFR 760.507 - Obligations of a participant.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...PROGRAMS INDEMNITY PAYMENT PROGRAMS Tree Assistance Program § 760.507 Obligations... (a) Eligible orchardists and nursery tree growers must execute all required documents... (b) Eligible orchardist or nursery tree growers must allow representatives...

  1. 7 CFR 760.507 - Obligations of a participant.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...PROGRAMS INDEMNITY PAYMENT PROGRAMS Tree Assistance Program § 760.507 Obligations... (a) Eligible orchardists and nursery tree growers must execute all required documents... (b) Eligible orchardist or nursery tree growers must allow representatives...

  2. 7 CFR 760.507 - Obligations of a participant.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...PROGRAMS INDEMNITY PAYMENT PROGRAMS Tree Assistance Program § 760.507 Obligations... (a) Eligible orchardists and nursery tree growers must execute all required documents... (b) Eligible orchardist or nursery tree growers must allow representatives...

  3. Genetic Transformation of an Obligate Anaerobe, P. gingivalis for FMN-Green Fluorescent Protein Expression in Studying Host-Microbe Interaction

    Microsoft Academic Search

    Chul Hee Choi; Jefferson V. Deguzman; Richard J. Lamont; Özlem Yilmaz; Olivier Neyrolles

    2011-01-01

    The recent introduction of “oxygen-independent” flavin mononucleotide (FMN)-based fluorescent proteins (FbFPs) is of major interest to both eukaryotic and prokaryotic microbial biologists. Accordingly, we demonstrate for the first time that an obligate anaerobe, the successful opportunistic pathogen of the oral cavity, Porphyromonas gingivalis, can be genetically engineered for expression of the non-toxic green FbFP. The resulting transformants are functional for

  4. Pathogen Life-History Trade-Offs Revealed in Allopatry

    PubMed Central

    Susi, Hanna; Laine, Anna-Liisa

    2013-01-01

    Trade-offs in life-history traits is a central tenet in evolutionary biology, yet their ubiquity and relevance to realized fitness in natural populations remains questioned. Trade-offs in pathogens are of particular interest because they may constrain the evolution and epidemiology of diseases. Here, we studied life-history traits determining transmission in the obligate fungal pathogen, Podosphaera plantaginis, infecting Plantago lanceolata. We find that although traits are positively associated on sympatric host genotypes, on allopatric host genotypes relationships between infectivity and subsequent transmission traits change shape, becoming even negative. The epidemiological prediction of this change in life-history relationships in allopatry is lower disease prevalence in newly established pathogen populations. An analysis of the natural pathogen metapopulation confirms that disease prevalence is lower in newly established pathogen populations and they are more prone to go extinct during winter than older pathogen populations. Hence, life-history trade-offs mediated by pathogen local adaptation may influence epidemiological dynamics at both population and metapopulation levels. PMID:24152013

  5. Long-Term Survival and Intracellular Replication of Mycoplasma hominis in Trichomonas vaginalis Cells: Potential Role of the Protozoon in Transmitting Bacterial Infection

    Microsoft Academic Search

    D. Dessi; Giuseppe Delogu; Eleonora Emonte; Maria Rosaria Catania; P. L. Fiori; P. Rappelli

    2005-01-01

    The existence of a symbiotic relationship between Trichomonas vaginalis and Mycoplasma hominis, which is the first reported example of symbiosis between two obligate human pathogens, has been recently reported by our research group. In this work, we examined the cellular location of M. hominis in respect to T. vaginalis .B y using gentamicin protection assays, double immunofluorescence, and confocal microscopy,

  6. Delivery of rifampicin-chitin nanoparticles into the intracellular compartment of polymorphonuclear leukocytes.

    PubMed

    Smitha, K T; Nisha, N; Maya, S; Biswas, Raja; Jayakumar, R

    2015-03-01

    Polymorphonuclear leukocytes (PMNs) provide the primary host defence against invading pathogens by producing reactive oxygen species (ROS) and microbicidal products. However, few pathogens can survive for a prolonged period of time within the PMNs. Additionally their intracellular lifestyle within the PMNs protect themselves from the additional lethal action of host immune systems such as antibodies and complements. Antibiotic delivery into the intracellular compartments of PMNs is a major challenge in the field of infectious diseases. In order to deliver antibiotics within the PMNs and for the better treatment of intracellular bacterial infections we synthesized rifampicin (RIF) loaded amorphous chitin nanoparticles (RIF-ACNPs) of 350±50 nm in diameter. RIF-ACNPs nanoparticles are found to be non-hemolytic and non-toxic against a variety of host cells. The release of rifampicin from the prepared nanoparticles was ?60% in 24 h, followed by a sustained pattern till 72 h. The RIF-ACNPs nanoparticles showed 5-6 fold enhanced delivery of RIF into the intracellular compartments of PMNs. The RIF-ACNPs showed anti-microbial activity against Escherichia coli, Staphylococcus aureus and a variety of other bacteria. In summary, our results suggest that RIF-ACNPs could be used to treat a variety of intracellular bacterial infections. PMID:25475841

  7. [Intracellular calcium: physiology and physiopathology].

    PubMed

    Missiaen, L; Callewaert, G; Parys, J B; Wuytack, F; Raeymaekers, L; Droogmans, G; Nilius, B; Eggermont, J; De Smedt, H

    2000-01-01

    Many important aspects of our life are regulated by the free cytosolic Ca2+ concentration. The intracellular Ca2+ signal is regulated both in space, frequency and amplitude. Each cell chooses a unique set of Ca2+ signals to control its function. Ca2+ signal transduction is based on rises in free cytosolic Ca2+ concentration. Ca2+ can come from the extracellular space or be released from intracellular stores. Extracellular Ca2+ enters the cell through various types of plasma-membrane Ca2+ channels and leaves the cell using Ca2+ pumps and Na+/Ca(2+)-exchangers. Ca2+ is accumulated in intracellular stores by means of Ca2+ pumps and is released via inositol 1,4,5-trisphosphate (IP3) and ryanodine receptors. Mutations or abnormalities in one of the above mentioned Ca(2+)-transporting proteins can lead to disease. Skeletal-muscle pathology can be caused by abnormal ryanodine receptors (malignant hyperthermia, porcine stress syndrome, central core disease), plasma-membrane Ca2+ channels (hypokalemic periodic paralysis, muscular dysgenesis mice, paraneoplastic Lambert-Eaton myasthenia syndrome) or Ca2+ pumps (Brody disease). Neurologic disorders can be related to altered function of plasma-membrane Ca2+ channels (episodic ataxia type 2, spinocerebellar ataxia type 6, familial hemiplegic migraine, glutamate excitotoxicity, tottering, leaner, lethargic and stargazer mice), IP3 receptors (Lowe's oculocerebrorenal syndrome, manic depression, Alzheimer's disease, opisthotonos mice) and Ca2+ pumps (deafwaddler mouse and wriggle mouse sagami). Two skin diseases are caused by Ca(2+)-pump mutations (Darier disease and Hailey-Hailey disease). Incomplete X-linked congenital stationary night blindness is caused by a mutation in the plasma-membrane Ca2+ channels in rods and cones. PMID:11196578

  8. The effects of macrophage source on the mechanism of phagocytosis and intracellular survival of Leishmania.

    PubMed

    Hsiao, Chia-Hung Christine; Ueno, Norikiyo; Shao, Jian Q; Schroeder, Kristin R; Moore, Kenneth C; Donelson, John E; Wilson, Mary E

    2011-11-01

    Leishmania spp. protozoa are obligate intracellular parasites that replicate in macrophages during mammalian infection. Efficient phagocytosis and survival in macrophages are important determinants of parasite virulence. Macrophage lines differ dramatically in their ability to sustain intracellular Leishmania infantum chagasi (Lic). We report that the U937 monocytic cell line supported the intracellular replication and cell-to-cell spread of Lic during 72 h after parasite addition, whereas primary human monocyte-derived macrophages (MDMs) did not. Electron microscopy and live cell imaging illustrated that Lic promastigotes anchored to MDMs via their anterior ends and were engulfed through symmetrical pseudopods. In contrast, U937 cells bound Lic in diverse orientations, and extended membrane lamellae to reorient and internalize parasites through coiling phagocytosis. Lic associated tightly with the parasitophorous vacuole (PV) membrane in both cell types. PVs fused with LAMP-1-expressing compartments 24 h after phagocytosis by MDMs, whereas U937 cell PVs remained LAMP-1 negative. The expression of one phagocytic receptor (CR3) was higher in MDMs than U937 cells, leading us to speculate that parasite uptake proceeds through dissimilar pathways between these cells. We hypothesize that the mechanism of phagocytosis differs between primary versus immortalized human macrophage cells, with corresponding differences in the subsequent intracellular fate of the parasite. PMID:21723411

  9. Barcoding Hedgehog for Intracellular Transport

    NSDL National Science Digital Library

    Thomas B. Kornberg (San Francisco; University of California REV)

    2011-11-22

    Hedgehog, an essential protein for the development of many vertebrate and invertebrate organs, signals at both short and long distances to control growth and patterning. The mechanism by which it moves between source and target cells is not known, but characterization of the covalent modification of its N terminus with palmitate and of its C terminus with cholesterol has led to the suggestion that the lipophilic properties of the modified protein serve to regulate movement after its secretion into the extracellular space. Another interpretation and model is that the C-terminal cholesterol acts to target Hedgehog to an intracellular trafficking pathway that prepares Hedgehog for release in an encapsulated form.

  10. A bioinformatic approach to understanding antibiotic resistance in intracellular bacteria through whole genome analysis.

    PubMed

    Biswas, Silpak; Raoult, Didier; Rolain, Jean-Marc

    2008-09-01

    Intracellular bacteria survive within eukaryotic host cells and are difficult to kill with certain antibiotics. As a result, antibiotic resistance in intracellular bacteria is becoming commonplace in healthcare institutions. Owing to the lack of methods available for transforming these bacteria, we evaluated the mechanisms of resistance using molecular methods and in silico genome analysis. The objective of this review was to understand the molecular mechanisms of antibiotic resistance through in silico comparisons of the genomes of obligate and facultative intracellular bacteria. The available data on in vitro mutants reported for intracellular bacteria were also reviewed. These genomic data were analysed to find natural mutations in known target genes involved in antibiotic resistance and to look for the presence or absence of different resistance determinants. Our analysis revealed the presence of tetracycline resistance protein (Tet) in Bartonella quintana, Francisella tularensis and Brucella ovis; moreover, most of the Francisella strains possessed the blaA gene, AmpG protein and metallo-beta-lactamase family protein. The presence or absence of folP (dihydropteroate synthase) and folA (dihydrofolate reductase) genes in the genome could explain natural resistance to co-trimoxazole. Finally, multiple genes encoding different efflux pumps were studied. This in silico approach was an effective method for understanding the mechanisms of antibiotic resistance in intracellular bacteria. The whole genome sequence analysis will help to predict several important phenotypic characteristics, in particular resistance to different antibiotics. In the future, stable mutants should be obtained through transformation methods in order to demonstrate experimentally the determinants of resistance in intracellular bacteria. PMID:18619818

  11. Intracellular ?-Amylase of Streptococcus mutans

    PubMed Central

    Simpson, Christine L.; Russell, Roy R. B.

    1998-01-01

    Sequencing upstream of the Streptococcus mutans gene for a CcpA gene homolog, regM, revealed an open reading frame, named amy, with homology to genes encoding ?-amylases. The deduced amino acid sequence showed a strong similarity (60% amino acid identity) to the intracellular ?-amylase of Streptococcus bovis and, in common with this enzyme, lacked a signal sequence. Amylase activity was found only in S. mutans cell extracts, with no activity detected in culture supernatants. Inactivation of amy by insertion of an antibiotic resistance marker confirmed that S. mutans has a single ?-amylase activity. The amylase activity was induced by maltose but not by starch, and no acid was produced from starch. S. mutans can, however, transport limit dextrins and maltooligosaccharides generated by salivary amylase, but inactivation of amy did not affect growth on these substrates or acid production. The amylase digested the glycogen-like intracellular polysaccharide (IPS) purified from S. mutans, but the amy mutant was able to digest and produce acid from IPS; thus, amylase does not appear to be essential for IPS breakdown. However, when grown on excess maltose, the amy mutant produced nearly threefold the amount of IPS produced by the parent strain. The role of Amy has not been established, but Amy appears to be important in the accumulation of IPS in S. mutans grown on maltose. PMID:9721315

  12. Intracellular Listeria monocytogenes Comprises a Minimal but Vital Fraction of the Intestinal Burden following Foodborne Infection.

    PubMed

    Jones, Grant S; Bussell, Kate M; Myers-Morales, Tanya; Fieldhouse, Abigail M; Bou Ghanem, Elsa N; D'Orazio, Sarah E F

    2015-08-01

    Listeria monocytogenes is a highly adaptive bacterium that replicates as a free-living saprophyte in the environment as well as a facultative intracellular pathogen that causes invasive foodborne infections. The intracellular life cycle of L. monocytogenes is considered to be its primary virulence determinant during mammalian infection; however, the proportion of L. monocytogenes that is intracellular in vivo has not been studied extensively. In this report, we demonstrate that the majority of wild-type (strain EGDe) and mouse-adapted (InlA(m)-expressing) L. monocytogenes recovered from the mesenteric lymph nodes (MLN) was extracellular within the first few days after foodborne infection. In addition, significantly lower burdens of L. monocytogenes were recovered from the colon, spleen, and liver of gentamicin-treated mice than of control mice. This led us to investigate whether intracellular replication of L. monocytogenes was essential during the intestinal phase of infection. We found that lipoate protein ligase-deficient L. monocytogenes (?lplA1) mutants, which display impaired intracellular growth, were able to colonize the colon but did not persist efficiently and had a significant defect in spreading to the MLN, spleen, and liver. Together, these data indicate that the majority of the L. monocytogenes burden in the gastrointestinal tract is extracellular, but the small proportion of intracellular L. monocytogenes is essential for dissemination to the MLN and systemic organs. PMID:26015479

  13. What are the public obligations to AIDS patients?

    PubMed

    Kelley, David

    2002-01-01

    The operating assumption in most discussions of health policy is that government has some responsibility for the health of its citizens and that it may legitimately tax, subsidize, and regulate its citizens in the exercise of that responsibility. On this assumption, public obligations to HIV/AIDS patients are a function of their needs in relationship to other health needs. This paper challenges the operating assumption by arguing that it cannot be grounded in the obligations that individuals have to each other. The paper rests on its own assumption: the moral theory of individualism. On this theory, individuals are ends in themselves who have the right to choose their own actions and uses of their resources; they do not have unchosen obligations to help others. In regard to HIV/AIDS patients, consequently, individuals have no duty to help, nor any other obligation beyond that of respecting their rights; and there is no valid basis for government regulations or subsidies on their behalf. The paper argues against the two approaches commonly used to defend a more expansive view of individual obligations and the role of government. The first is the assumption of welfare rights to goods and services; the second is the assumption that distributive justice requires some redistribution of health care resources. PMID:15971567

  14. Delineation of Diverse Macrophage Activation Programs in Response to Intracellular Parasites and Cytokines

    PubMed Central

    Zhang, Shuyi; Kim, Charles C.; Batra, Sajeev; McKerrow, James H.; Loke, P'ng

    2010-01-01

    Background The ability to reside and proliferate in macrophages is characteristic of several infectious agents that are of major importance to public health, including the intracellular parasites Trypanosoma cruzi (the etiological agent of Chagas disease) and Leishmania species (etiological agents of Kala-Azar and cutaneous leishmaniasis). Although recent studies have elucidated some of the ways macrophages respond to these pathogens, the relationships between activation programs elicited by these pathogens and the macrophage activation programs elicited by bacterial pathogens and cytokines have not been delineated. Methodology/Principal Findings To provide a global perspective on the relationships between macrophage activation programs and to understand how certain pathogens circumvent them, we used transcriptional profiling by genome-wide microarray analysis to compare the responses of mouse macrophages following exposure to the intracellular parasites T. cruzi and Leishmania mexicana, the bacterial product lipopolysaccharide (LPS), and the cytokines IFNG, TNF, IFNB, IL-4, IL-10, and IL-17. We found that LPS induced a classical activation state that resembled macrophage stimulation by the Th1 cytokines IFNG and TNF. However, infection by the protozoan pathogen L. mexicana produced so few transcriptional changes that the infected macrophages were almost indistinguishable from uninfected cells. T. cruzi activated macrophages produced a transcriptional signature characterized by the induction of interferon-stimulated genes by 24 h post-infection. Despite this delayed IFN response by T. cruzi, the transcriptional response of macrophages infected by the kinetoplastid pathogens more closely resembled the transcriptional response of macrophages stimulated by the cytokines IL-4, IL-10, and IL-17 than macrophages stimulated by Th1 cytokines. Conclusions/Significance This study provides global gene expression data for a diverse set of biologically significant pathogens and cytokines and identifies the relationships between macrophage activation states induced by these stimuli. By comparing macrophage activation programs to pathogens and cytokines under identical experimental conditions, we provide new insights into how macrophage responses to kinetoplastids correlate with the overall range of macrophage activation states. PMID:20361029

  15. Pathogenic adaptations to host-derived antibacterial copper

    PubMed Central

    Chaturvedi, Kaveri S.; Henderson, Jeffrey P.

    2014-01-01

    Recent findings suggest that both host and pathogen manipulate copper content in infected host niches during infections. In this review, we summarize recent developments that implicate copper resistance as an important determinant of bacterial fitness at the host-pathogen interface. An essential mammalian nutrient, copper cycles between copper (I) (Cu+) in its reduced form and copper (II) (Cu2+) in its oxidized form under physiologic conditions. Cu+ is significantly more bactericidal than Cu2+ due to its ability to freely penetrate bacterial membranes and inactivate intracellular iron-sulfur clusters. Copper ions can also catalyze reactive oxygen species (ROS) generation, which may further contribute to their toxicity. Transporters, chaperones, redox proteins, receptors and transcription factors and even siderophores affect copper accumulation and distribution in both pathogenic microbes and their human hosts. This review will briefly cover evidence for copper as a mammalian antibacterial effector, the possible reasons for this toxicity, and pathogenic resistance mechanisms directed against it. PMID:24551598

  16. Host-pathogen interactions: Host resistance factor Nramp1 up-regulates the expression of Salmonella pathogenicity island-2 virulence genes

    Microsoft Academic Search

    Michelle L. Zaharik; Bruce A. Vallance; José L. Puente; Philippe Gros; B. Brett Finlay

    2002-01-01

    Nramp1 (Natural resistance-associated macrophage protein-1; also known as Slc11a1) is a host resistance gene that provides protection against several intracellular pathogens, including Salmonella enterica serovar Typhimurium. Little is known about the dynamic interplay that occurs between mammalian host resistance determinants such as Nramp1 and pathogens during infection. To explore these interactions, we examined the effect of Nramp1 on expression of

  17. Intracellular survival of Candida glabrata in macrophages: immune evasion and persistence.

    PubMed

    Kasper, Lydia; Seider, Katja; Hube, Bernhard

    2015-08-01

    Candida glabrata is a successful human opportunistic pathogen which causes superficial but also life-threatening systemic infections. During infection, C. glabrata has to cope with cells of the innate immune system such as macrophages, which belong to the first line of defense against invading pathogens. Candida glabrata is able to survive and even replicate inside macrophages while causing surprisingly low damage and cytokine release. Here, we present an overview of recent studies dealing with the interaction of C. glabrata with macrophages, from phagocytosis to intracellular growth and escape. We review the strategies of C. glabrata that permit intracellular survival and replication, including poor host cell activation, modification of phagosome maturation and phagosome pH, adaptation to antimicrobial activities, and mechanisms to overcome the nutrient limitations within the phagosome. In summary, these studies suggest that survival within macrophages may be an immune evasion and persistence strategy of C. glabrata during infection. PMID:26066553

  18. Identification of Host-Dependent Survival Factors for Intracellular Mycobacterium tuberculosis through an siRNA Screen

    Microsoft Academic Search

    Shilpi Jayaswal; Raina Dua; Shashank Gupta; Tanmay Majumdar; Gobardhan Das; Dhiraj Kumar; Kanury V. S. Rao

    2010-01-01

    The stable infection of host macrophages by Mycobacterium tuberculosis (Mtb) involves, and depends on, the attenuation of the diverse microbicidal responses mounted by the host cell. This is primarily achieved through targeted perturbations of the host cellular signaling machinery. Therefore, in view of the dependency of the pathogen on host molecules for its intracellular survival, we wanted to test whether

  19. Legionella pneumophila Philadelphia1 tatB and tatC affect intracellular replication and biofilm formation

    Microsoft Academic Search

    Emmy De Buck; Liesbeth Maes; Eef Meyen; Lieve Van Mellaert; Nick Geukens; Jozef Anné; Elke Lammertyn

    2005-01-01

    Legionella pneumophila is a facultative intracellular human pathogen and an important cause of Legionnaires’ disease, a severe form of pneumonia. Recently, we showed the presence of a putative twin-arginine translocation (Tat) pathway in L. pneumophila Philadelphia-1. This secretion pathway is used to transport completely folded proteins across the cytoplasmic membrane. The importance of the Tat pathway in L. pneumophila was

  20. Human Natural Killer Cells Mediate Killing of Intracellular Mycobacterium tuberculosis H37Rv via Granule-Independent Mechanisms

    Microsoft Academic Search

    KEVIN J. BRILL; QING LI; RHONDA LARKIN; DAVID H. CANADAY; DAVID R. KAPLAN; W. HENRY BOOM; RICHARD F. SILVER

    2001-01-01

    Despite the continued importance of tuberculosis as a world-wide threat to public health, little is known about the mechanisms used by human lymphocytes to contain and kill the intracellular pathogen Mycobacte- rium tuberculosis. We previously described an in vitro model of infection of human monocytes (MN) with virulent M. tuberculosis strain H37Rv in which the ability of peripheral blood lymphocytes

  1. Settling Down: The Genome of Serratia symbiotica from the Aphid Cinara tujafilina Zooms in on the Process of Accommodation to a Cooperative Intracellular Life

    PubMed Central

    Manzano-Marín, Alejandro; Latorre, Amparo

    2014-01-01

    Particularly interesting cases of mutualistic endosymbioses come from the establishment of co-obligate associations of more than one species of endosymbiotic bacteria. Throughout symbiotic accommodation from a free-living bacterium, passing through a facultative stage and ending as an obligate intracellular one, the symbiont experiences massive genomic losses and phenotypic adjustments. Here, we scrutinized the changes in the coevolution of Serratia symbiotica and Buchnera aphidicola endosymbionts in aphids, paying particular attention to the transformations undergone by S. symbiotica to become an obligate endosymbiont. Although it is already known that S. symbiotica is facultative in Acyrthosiphon pisum, in Cinara cedri it has established a co-obligate endosymbiotic consortium along with B. aphidicola to fulfill the aphid’s nutritional requirements. The state of this association in C. tujafilina, an aphid belonging to the same subfamily (Lachninae) that C. cedri, remained unknown. Here, we report the genome of S. symbiotica strain SCt-VLC from the aphid C. tujafilina. While being phylogenetically and genomically very closely related to the facultative endosymbiont S. symbiotica from the aphid A. pisum, it shows a variety of metabolic, genetic, and architectural features, which point toward this endosymbiont being one step closer to an obligate intracellular one. We also describe in depth the process of genome rearrangements suffered by S. symbiotica and the role mobile elements play in gene inactivations. Finally, we postulate the supply to the host of the essential riboflavin (vitamin B2) as key to the establishment of S. symbiotica as a co-obligate endosymbiont in the aphids belonging to the subfamily Lachninane. PMID:24951564

  2. Stress adaptation in a pathogenic fungus

    PubMed Central

    Brown, Alistair J. P.; Budge, Susan; Kaloriti, Despoina; Tillmann, Anna; Jacobsen, Mette D.; Yin, Zhikang; Ene, Iuliana V.; Bohovych, Iryna; Sandai, Doblin; Kastora, Stavroula; Potrykus, Joanna; Ballou, Elizabeth R.; Childers, Delma S.; Shahana, Shahida; Leach, Michelle D.

    2014-01-01

    Candida albicans is a major fungal pathogen of humans. This yeast is carried by many individuals as a harmless commensal, but when immune defences are perturbed it causes mucosal infections (thrush). Additionally, when the immune system becomes severely compromised, C. albicans often causes life-threatening systemic infections. A battery of virulence factors and fitness attributes promote the pathogenicity of C. albicans. Fitness attributes include robust responses to local environmental stresses, the inactivation of which attenuates virulence. Stress signalling pathways in C. albicans include evolutionarily conserved modules. However, there has been rewiring of some stress regulatory circuitry such that the roles of a number of regulators in C. albicans have diverged relative to the benign model yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe. This reflects the specific evolution of C. albicans as an opportunistic pathogen obligately associated with warm-blooded animals, compared with other yeasts that are found across diverse environmental niches. Our understanding of C. albicans stress signalling is based primarily on the in vitro responses of glucose-grown cells to individual stresses. However, in vivo this pathogen occupies complex and dynamic host niches characterised by alternative carbon sources and simultaneous exposure to combinations of stresses (rather than individual stresses). It has become apparent that changes in carbon source strongly influence stress resistance, and that some combinatorial stresses exert non-additive effects upon C. albicans. These effects, which are relevant to fungus–host interactions during disease progression, are mediated by multiple mechanisms that include signalling and chemical crosstalk, stress pathway interference and a biological transistor. PMID:24353214

  3. Multiple Genetic Elements Carry the Tetracycline Resistance Gene tet(W) in the Animal Pathogen Arcanobacterium pyogenes

    Microsoft Academic Search

    Stephen J. Billington; B. Helen Jost

    2006-01-01

    The tet(W) gene is associated with tetracycline resistance in a wide range of bacterial species, including obligately anaerobic rumen bacteria and isolates from the human gut and oral mucosa. However, little is known about how this gene is disseminated and the types of genetic elements it is carried on. We examined tetracycline-resistant isolates of the animal commensal and opportunistic pathogen

  4. 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

  5. Intracellular Delivery and Antibacterial Activity of Gentamicin Encapsulated in pH-Sensitive Liposomes

    PubMed Central

    Lutwyche, Peter; Cordeiro, Carol; Wiseman, David J.; St-Louis, Maryse; Uh, Mitchell; Hope, Michael J.; Webb, Murray S.; Finlay, B. Brett

    1998-01-01

    Cell membranes are relatively impermeable to the antibiotic gentamicin, a factor that, along with the toxicity of gentamicin, precludes its use against many important intracellular bacterial infections. Liposomal encapsulation of this drug was used in order to achieve intracellular antibiotic delivery and therefore increase the drug’s therapeutic activity against intracellular pathogens. Gentamicin encapsulation in several dipalmitoylphosphatidylcholine (DPPC) and pH-sensitive dioleoylphosphatidylethanolamine (DOPE)-based carrier systems was characterized. To systematically test the antibacterial efficacies of these formulations, a tissue culture assay system was developed wherein murine macrophage-like J774A.1 cells were infected with bacteria and were then treated with encapsulated drug. Of these formulations, DOPE–N-succinyl-DOPE and DOPE–N-glutaryl-DOPE (70:30;mol:mol) containing small amounts of polyethyleneglycol-ceramide showed appreciable antibacterial activities, killing greater than 75% of intracellular vacuole-resident wild-type Salmonella typhimurium compared to the level of killing of the control formulations. These formulations also efficiently eliminated intracellular infections caused by a recombinant hemolysin-expressing S. typhimurium strain and a Listeria monocytogenes strain, both of which escape the vacuole and reside in the cytoplasm. Control non-pH-sensitive liposomal formulations of gentamicin had poor antibacterial activities. A fluorescence resonance energy transfer assay indicated that the efficacious formulations undergo a pH-dependent lipid mixing and fusion event. Intracellular delivery of the fluorescent molecules encapsulated in these formulations was confirmed by confocal fluorescence microscopy and was shown to be dependent on endosomal acidification. This work shows that encapsulation of membrane-impermeative antibiotics in appropriately designed lipid-based delivery systems can enable their use in treating intracellular infections and details the development of a general assay for testing the intracellular delivery of encapsulated drug formulations. PMID:9756749

  6. Two phases of intracellular reactive oxygen species production during victorin-induced cell death in oats

    Microsoft Academic Search

    Masaru Sakamoto; Yasuomi Tada; Hitoshi Nakayashiki; Yukio Tosa; Shigeyuki Mayama

    2005-01-01

    Reactive oxygen species (ROS) are thought to be involved in various forms of programmed cell death (PCD) in animal and plant\\u000a cells. PCD, along with the production of ROS, occurs during plant–pathogen interactions. Here we show that victorin, a host-specific\\u000a toxin produced by Cochliobolus victoriae, which causes victoria blight of oats, induces two phases of intracellular ROS production in victorin-sensitive

  7. Host cell death induced by the egress of intracellular Plasmodium parasites

    Microsoft Academic Search

    Volker Heussler; Annika Rennenberg; Rebecca Stanway

    2010-01-01

    Intracellular pathogens are known to inhibit host cell apoptosis efficiently to ensure their own survival. However, following\\u000a replication within a cell, they typically need to egress in order to infect new cells. For a long time it was assumed that\\u000a this happens by simply disrupting the host cell and in some cases, such as for Plasmodium-infected erythrocytes, this seems indeed

  8. Eradication of intracellular Francisella tularensis in THP1 human macrophages with a novel autophagy inducing agent

    Microsoft Academic Search

    Hao-Chieh Chiu; Shilpa Soni; Samuel K Kulp; Heather Curry; Dasheng Wang; John S Gunn; Larry S Schlesinger; Ching-Shih Chen

    2009-01-01

    BACKGROUND: Autophagy has been shown recently to play an important role in the intracellular survival of several pathogenic bacteria. In this study, we investigated the effect of a novel small-molecule autophagy-inducing agent, AR-12, on the survival of Francisella tularensis, the causative bacterium of tularemia in humans and a potential bioterrorism agent, in macrophages. METHODS AND RESULTS: Our results show that

  9. Salmonella enterica serovars Typhimurium and Typhi as model organisms: revealing paradigm of host-pathogen interactions.

    PubMed

    Garai, Preeti; Gnanadhas, Divya Prakash; Chakravortty, Dipshikha

    2012-07-01

    The lifestyle of intracellular pathogens has always questioned the skill of a microbiologist in the context of finding the permanent cure to the diseases caused by them. The best tool utilized by these pathogens is their ability to reside inside the host cell, which enables them to easily bypass the humoral immunity of the host, such as the complement system. They further escape from the intracellular immunity, such as lysosome and inflammasome, mostly by forming a protective vacuole-bound niche derived from the host itself. Some of the most dreadful diseases are caused by these vacuolar pathogens, for example, tuberculosis by Mycobacterium or typhoid fever by Salmonella. To deal with such successful pathogens therapeutically, the knowledge of a host-pathogen interaction system becomes primarily essential, which further depends on the use of a model system. A well characterized pathogen, namely Salmonella, suits the role of a model for this purpose, which can infect a wide array of hosts causing a variety of diseases. This review focuses on various such aspects of research on Salmonella which are useful for studying the pathogenesis of other intracellular pathogens. PMID:22722237

  10. Recent Developments in Copper and Zinc Homeostasis in Bacterial Pathogens

    PubMed Central

    Braymer, Joseph J.; Giedroc, David P.

    2014-01-01

    Copper and zinc homeostasis systems in pathogenic bacteria are required to resist host efforts to manipulate the availability and toxicity of these metal ions. Central to this microbial adaptive response is the involvement of metal-trafficking and -sensing proteins that ultimately exercise control of metal speciation in the cell. Cu- and Zn-specific metalloregulatory proteins regulate the transcription of metal-responsive genes while metallochaperones and related proteins ensure that these metals are appropriately buffered by the intracellular milieu and delivered to correct intracellular targets. In this review, we summarize recent findings on how bacterial pathogens mount a metal-specific response to derail host efforts to win the “fight over metals.” PMID:24463765

  11. Invariant natural killer T cells: boon or bane in immunity to intracellular bacterial infections?

    PubMed

    Shekhar, Sudhanshu; Joyee, Antony George; Yang, Xi

    2014-01-01

    Invariant natural killer T (iNKT) cells represent a specialized subset of innate lymphocytes that recognize lipid and glycolipid antigens presented to them by nonclassical MHC-I CD1d molecules and are able to rapidly secrete copious amounts of a variety of cytokines. iNKT cells possess the ability to modulate innate as well as adaptive immune responses against various pathogens. Intracellular bacteria are one of the most clinically significant human pathogens that effectively evade the immune system and cause a myriad of diseases of public health concern globally. Emerging evidence suggests that iNKT cells can confer immunity to intracellular bacteria but also inflict pathology in certain cases. We summarize the current knowledge on the contribution of iNKT cells in the host defense against intracellular bacterial infections, with a focus on the underlying mechanisms by which these cells induce protective or pathogenic reactions including the pathways of direct action (acting on infected cells) and indirect action (modulating dendritic, NK and T cells). The rational exploitation of iNKT cells for prophylactic and therapeutic purposes awaits a profound understanding of their functional biology. PMID:24903638

  12. Plasmodesmata dynamics are coordinated by intracellular signaling pathways

    PubMed Central

    Brunkard, Jacob O.; Runkel, Anne M.; Zambryski, Patricia C.

    2013-01-01

    Membrane-lined channels called plasmodesmata (PD) connect the cytoplasts of adjacent plant cells across the cell wall, permitting intercellular movement of small molecules, proteins, and RNA. Recent genetic screens for mutants with altered PD transport identified genes suggesting that chloroplasts play crucial roles in coordinating PD transport. Complementing this discovery, studies manipulating expression of PD-localized proteins imply that changes in PD transport strongly impact chloroplast biology. Ongoing efforts to find genes that control root and stomatal development reveal the critical role of PD in enforcing tissue patterning, and newly discovered PD-localized proteins show that PD influence development, intracellular signaling, and defense against pathogens. Together, these studies demonstrate that PD function and formation are tightly integrated with plant physiology. PMID:23978390

  13. Intracellular Signaling by the Unfolded Protein

    E-print Network

    Mullins, Dyche

    Intracellular Signaling by the Unfolded Protein Response Sebasti´an Bernales,1 Feroz R. Papa,2 reticulum stress, signal transduction, organelle homeostasis, protein folding, regulated mRNA splicing, translational control Abstract The unfolded protein response (UPR) is an intracellular signaling pathway

  14. Buckling and force propagation along intracellular microtubules

    E-print Network

    MacKintosh, F.C.

    OFFPRINT Buckling and force propagation along intracellular microtubules Moumita Das, Alex J propagation along intracellular microtubules Moumita Das1,2(a) , Alex J. Levine3 and F. C. MacKintosh1,2 1 September 2008 PACS 87.16.Ka ­ Filaments, microtubules, their networks, and supramolecular assemblies PACS

  15. Spatiological processes in intracellular signalling Michael Fisher

    E-print Network

    Malcolm, Grant

    capabilities suggestive information processing activities. first sections this paper we selectively reviewBioSystems 55 (2000) Spatio­logical processes in intracellular signalling Michael Fisher a Grant. Recent findings from experimental biology indicate that many intracellular signalling systems show a high

  16. Flavobacteria as Intracellular Symbionts in Cockroaches

    Microsoft Academic Search

    Claudio Bandi; Giuseppe Damiani; Lorenzo Magrassi; Aldo Grigolo; Renato Fani; Luciano Sacchi

    1994-01-01

    Animal cells are the sole habitat for a variety of bacteria. Molecular sequence data have been used to position a number of these intracellular microorganisms in the overall scheme of eubacterial evolution. Most of them have been classified as proteobacteria or chlamydiae. Here we present molecular evidence placing an intracellular symbiont among the flavobacteria-bacteroides. This microorganism inhabits specialized cells in

  17. Plant pathogenic Pseudomonas species

    Microsoft Academic Search

    Monica Höfte; PAUL DE VOS

    In the current taxonomy, plant pathogenic Pseudomonas species are restricted to rRNA group I organisms belonging to the Gamma subclass of Proteobacteria. Currently, about 21 validly described plant pathogenic Pseudomonas species are known. The most important species is P. syringae with more than 50 described pathovars. The pathovar concept is confusing and the taxonomy of P. syringae needs revision. P.

  18. 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...

  19. Emerging foodborne pathogens

    Microsoft Academic Search

    Robert V. Tauxe

    2002-01-01

    The broad spectrum of foodborne infections has changed dramatically over time, as well-established pathogens have been controlled or eliminated, and new ones have emerged. The burden of foodborne disease remains substantial: one in four Americans is estimated to have a significant foodborne illness each year. The majority of these illnesses are not accounted for by known pathogens, so more must

  20. Pathogen inactivation techniques.

    PubMed

    Pelletier, J P R; Transue, S; Snyder, E L

    2006-01-01

    The desire to rid the blood supply of pathogens of all types has led to the development of many technologies aimed at the same goal--eradication of the pathogen(s) without harming the blood cells or generating toxic chemical agents. This is a very ambitious goal, and one that has yet to be achieved. One approach is to shun the 'one size fits all' concept and to target pathogen-reduction agents at the Individual component types. This permits the development of technologies that might be compatible with, for example, plasma products but that would be cytocidal and thus incompatible with platelet concentrates or red blood cell units. The technologies to be discussed include solvent detergent and methylene blue treatments--designed to inactivate plasma components and derivatives; psoralens (S-59--amotosalen) designed to pathogen-reduce units of platelets; and two products aimed at red blood cells, S-303 (a Frale--frangible anchor-linker effector compound) and Inactine (a binary ethyleneimine). A final pathogen-reduction material that might actually allow one material to inactivate all three blood components--riboflavin (vitamin B2)--is also under development. The sites of action of the amotosalen (S-59), the S-303 Frale, Inactine, and riboflavin are all localized in the nucleic acid part of the pathogen. Solvent detergent materials act by dissolving the plasma envelope, thus compromising the integrity of the pathogen membrane and rendering it non-infectious. By disrupting the pathogen's ability to replicate or survive, its infectivity is removed. The degree to which bacteria and viruses are affected by a particular pathogen-reducing technology relates to its Gram-positive or Gram-negative status, to the sporulation characteristics for bacteria, and the presence of lipid or protein envelopes for viruses. Concerns related to photoproducts and other breakdown products of these technologies remain, and the toxicology of pathogen-reduction treatments is a major ongoing area of investigation. Clearly, regulatory agencies have a major role to play in the evaluation of these new technologies. This chapter will cover the several types of pathogen-reduction systems, mechanisms of action, the inactivation efficacy for specific types of pathogens, toxicology of the various systems and the published research and clinical trial data supporting their potential usefulness. Due to the nature of the field, pathogen reduction is a work in progress and this review should be considered as a snapshot in time rather than a clear picture of what the future will bring. PMID:16377551

  1. Filial obligations to elderly parents: a duty to care?

    PubMed

    Stuifbergen, Maria C; Van Delden, Johannes J M

    2011-02-01

    A continuing need for care for elderly, combined with looser family structures prompt the question what filial obligations are. Do adult children of elderly have a duty to care? Several theories of filial obligation are reviewed. The reciprocity argument is not sensitive to the parent-child relationship after childhood. A theory of friendship does not offer a correct parallel for the relationship between adult child and elderly parent. Arguments based on need or vulnerability run the risk of being unjust to those on whom a needs-based claim is laid. To compare filial obligations with promises makes too much of parents' expectations, however reasonable they may be. The good of being in an unchosen relationship seems the best basis for filial obligations, with an according duty to maintain the relationship when possible. We suggest this relationship should be maintained even if one of the parties is no longer capable of consciously contributing to it. We argue that this entails a duty to care about one's parents, not for one's parents. This implies that care for the elderly is not in the first place a task for adult children. PMID:20922568

  2. Clinical review: Influenza pandemic – physicians and their obligations

    Microsoft Academic Search

    Devanand Anantham; Wendy McHugh; Stephen O'Neill; Lachlan Forrow

    2008-01-01

    An influenza pandemic threatens to be the most lethal public health crisis to confront the world. Physicians will have critical roles in diagnosis, containment and treatment of influenza, and their commitment to treat despite increased personal risks is essential for a successful public health response. The obligations of the medical profession stem from the unique skills of its practitioners, who

  3. European air transport public service obligations: a periodic review

    Microsoft Academic Search

    Aisling Reynolds-Feighan

    1995-01-01

    The ‘Third Package’ of European Union air transport liberalisation measures came into effect on 1 January 1993 and has substantially reduced the restrictions on interstate flight operations. The package of measures also includes provision for the member states to impose ‘public service obligations’ on low-density routes which were deemed necessary for the purposes of regional development. In this paper, it

  4. A test for obligate apomixis in grain sorghum R473

    Microsoft Academic Search

    D. R. Marshall; R. W. Downes

    1977-01-01

    Segregation patterns in progeny arrays of selfed plants, heterozygous for the Mdh 1 isozyme marker locus, were used in an attempt to confirm the presence of apomixis in the grain sorghum line R473. No evidence for obligate apomictic reproduction was obtained. However, our studies did not rule out the possibility of a low level of facultative apomixis in R473.

  5. 24 CFR 891.755 - Obligations of the family.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    24 ? Housing and Urban Development ? 4 ? 2012-04-01 ? 2012-04-01 ? false ? Obligations of the family. ? 891.755 ? Section 891.755 ? Housing and Urban Development ? REGULATIONS RELATING TO HOUSING AND URBAN DEVELOPMENT (CONTINUED) ? OFFICE OF THE ASSISTANT SECRETARY FOR HOUSING-FEDERAL...

  6. Smoking Policies: An Analysis of School District Obligation and Liability.

    ERIC Educational Resources Information Center

    Hartmeister, Fred

    1990-01-01

    Begins with a brief review of scientific research on adverse health consequences caused by smoking, then examines the school district role in balancing competing interests of smokers and nonsmokers. States that school districts have a financial and moral obligation to reduce potential health risks and legal liabilities (148 references) (MLF)

  7. 7 CFR 930.163 - Deferment of restricted obligation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...NUTS), DEPARTMENT OF AGRICULTURE TART CHERRIES GROWN IN THE STATES OF MICHIGAN, NEW...a surety bond on restricted percentage cherries to be posted to temporarily defer the...times the market value of the quantity of cherries for which the holding obligation...

  8. 7 CFR 930.163 - Deferment of restricted obligation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...NUTS), DEPARTMENT OF AGRICULTURE TART CHERRIES GROWN IN THE STATES OF MICHIGAN, NEW...a surety bond on restricted percentage cherries to be posted to temporarily defer the...times the market value of the quantity of cherries for which the holding obligation...

  9. 7 CFR 930.163 - Deferment of restricted obligation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...Nuts), DEPARTMENT OF AGRICULTURE TART CHERRIES GROWN IN THE STATES OF MICHIGAN, NEW...a surety bond on restricted percentage cherries to be posted to temporarily defer the...times the market value of the quantity of cherries for which the holding obligation...

  10. 7 CFR 930.163 - Deferment of restricted obligation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...Nuts), DEPARTMENT OF AGRICULTURE TART CHERRIES GROWN IN THE STATES OF MICHIGAN, NEW...a surety bond on restricted percentage cherries to be posted to temporarily defer the...times the market value of the quantity of cherries for which the holding obligation...

  11. 7 CFR 930.163 - Deferment of restricted obligation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...Nuts), DEPARTMENT OF AGRICULTURE TART CHERRIES GROWN IN THE STATES OF MICHIGAN, NEW...a surety bond on restricted percentage cherries to be posted to temporarily defer the...times the market value of the quantity of cherries for which the holding obligation...

  12. Classification Revisions Reduce Reported Federal Development Obligations. InfoBrief.

    ERIC Educational Resources Information Center

    Jankowski, John E.

    This document reports on federal Research and Development (R&D) funding trends for the last 10 years and explains the sources of Federal R&D revisions. The data are obtained from an annual census of approximately 30 federal agencies that report obligation data to the National Science Foundation Survey of Federal Funds for R&D. (YDS)

  13. Tracking Trends In Provider Reimbursements And Patient Obligations.

    PubMed

    Hempstead, Katherine; Sung, Iyue; Gray, Joshua; Richardson, Stewart

    2015-07-01

    Primary payments-those made by insurance carriers-to office-based physicians rose moderately between 2013 and 2014. Payments declined for orthopedics and surgery while increasing for primary care and obstetrics-gynecology. Patients' payment obligations rose for all specialties, and deductibles were the largest category of increased patient spending. PMID:26153318

  14. The Obligate Mutualist Wigglesworthia glossinidia Influences Reproduction, Digestion, and Immunity Processes of Its Host, the Tsetse Fly?

    PubMed Central

    Pais, Roshan; Lohs, Claudia; Wu, Yineng; Wang, Jingwen; Aksoy, Serap

    2008-01-01

    Tsetse flies (Diptera: Glossinidae) are vectors for trypanosome parasites, the agents of the deadly sleeping sickness disease in Africa. Tsetse also harbor two maternally transmitted enteric mutualist endosymbionts: the primary intracellular obligate Wigglesworthia glossinidia and the secondary commensal Sodalis glossinidius. Both endosymbionts are transmitted to the intrauterine progeny through the milk gland secretions of the viviparous female. We administered various antibiotics either continuously by per os supplementation of the host blood meal diet or discretely by hemocoelic injections into fertile females in an effort to selectively eliminate the symbionts to study their individual functions. A symbiont-specific PCR amplification assay and fluorescence in situ hybridization analysis were used to evaluate symbiont infection outcomes. Tetracycline and rifampin treatments eliminated all tsetse symbionts but reduced the fecundity of the treated females. Ampicillin treatments did not affect the intracellular Wigglesworthia localized in the bacteriome organ and retained female fecundity. The resulting progeny of ampicillin-treated females, however, lacked Wigglesworthia but still harbored the commensal Sodalis. Our results confirm the presence of two physiologically distinct Wigglesworthia populations: the bacteriome-localized Wigglesworthia involved with nutritional symbiosis and free-living Wigglesworthia in the milk gland organ responsible for maternal transmission to the progeny. We evaluated the reproductive fitness, longevity, digestion, and vectorial competence of flies that were devoid of Wigglesworthia. The absence of Wigglesworthia completely abolished the fertility of females but not that of males. Both the male and female Wigglesworthia-free adult progeny displayed longevity costs and were significantly compromised in their blood meal digestion ability. Finally, while the vectorial competence of the young newly hatched adults without Wigglesworthia was comparable to that of their wild-type counterparts, older flies displayed higher susceptibility to trypanosome infections, indicating a role for the mutualistic symbiosis in host immunobiology. The ability to rear adult tsetse that lack the obligate Wigglesworthia endosymbionts will now enable functional investigations into this ancient symbiosis. PMID:18689507

  15. The obligate mutualist Wigglesworthia glossinidia influences reproduction, digestion, and immunity processes of its host, the tsetse fly.

    PubMed

    Pais, Roshan; Lohs, Claudia; Wu, Yineng; Wang, Jingwen; Aksoy, Serap

    2008-10-01

    Tsetse flies (Diptera: Glossinidae) are vectors for trypanosome parasites, the agents of the deadly sleeping sickness disease in Africa. Tsetse also harbor two maternally transmitted enteric mutualist endosymbionts: the primary intracellular obligate Wigglesworthia glossinidia and the secondary commensal Sodalis glossinidius. Both endosymbionts are transmitted to the intrauterine progeny through the milk gland secretions of the viviparous female. We administered various antibiotics either continuously by per os supplementation of the host blood meal diet or discretely by hemocoelic injections into fertile females in an effort to selectively eliminate the symbionts to study their individual functions. A symbiont-specific PCR amplification assay and fluorescence in situ hybridization analysis were used to evaluate symbiont infection outcomes. Tetracycline and rifampin treatments eliminated all tsetse symbionts but reduced the fecundity of the treated females. Ampicillin treatments did not affect the intracellular Wigglesworthia localized in the bacteriome organ and retained female fecundity. The resulting progeny of ampicillin-treated females, however, lacked Wigglesworthia but still harbored the commensal Sodalis. Our results confirm the presence of two physiologically distinct Wigglesworthia populations: the bacteriome-localized Wigglesworthia involved with nutritional symbiosis and free-living Wigglesworthia in the milk gland organ responsible for maternal transmission to the progeny. We evaluated the reproductive fitness, longevity, digestion, and vectorial competence of flies that were devoid of Wigglesworthia. The absence of Wigglesworthia completely abolished the fertility of females but not that of males. Both the male and female Wigglesworthia-free adult progeny displayed longevity costs and were significantly compromised in their blood meal digestion ability. Finally, while the vectorial competence of the young newly hatched adults without Wigglesworthia was comparable to that of their wild-type counterparts, older flies displayed higher susceptibility to trypanosome infections, indicating a role for the mutualistic symbiosis in host immunobiology. The ability to rear adult tsetse that lack the obligate Wigglesworthia endosymbionts will now enable functional investigations into this ancient symbiosis. PMID:18689507

  16. Processes for managing pathogens.

    PubMed

    Godfree, Alan; Farrell, Joseph

    2005-01-01

    Wastewater contains human, animal, and plant pathogens capable of causing viral, bacterial, or parasitic infections. There are several routes whereby sewage pathogens may affect human health, including direct contact, contamination of food crops, zoonoses, and vectors. The range and numbers of pathogens in municipal wastewater vary with the level of endemic disease in the community, discharges from commercial activities, and seasonal factors. Regulations to control pathogen risk in the United States and Europe arising from land application of biosolids are based on the concept of multiple barriers to the prevention of transmission. The barriers are (i) treatment to reduce pathogen content and vector attraction, (ii) restrictions on crops grown on land to which biosolids have been applied, and (iii) minimum intervals following application and grazing or harvesting. Wastewater treatment reduces number of pathogens in the wastewater by concentrating them with the solids in the sludge. Although some treatment processes are designed specifically to inactivate pathogens, many are not, and the actual mechanisms of microbial inactivation are not fully understood for all processes. Vector attraction is reduced by stabilization (reduction of readily biodegradable material) and/or incorporation immediately following application. Concerns about health risks have renewed interest in the effects of treatment (on pathogens) and advanced treatment methods, and work performed in the United States suggests that Class A pathogen reduction can be achieved less expensively than previously thought. Effective pathogen risk management requires control to the complete chain of sludge treatment, biosolids handling and application, and post-application activities. This may be achieved by adherence to quality management systems based on hazard analysis critical control point (HACCP) principles. PMID:15647539

  17. The intracellular location, mechanisms and outcomes of NOD1 signaling.

    PubMed

    Kaparakis-Liaskos, Maria

    2015-08-01

    The host has developed an array of systems that enables protection against infection and response to injury, ultimately resulting in the generation of a pro-inflammatory response. The most rapid immune response is mediated via the innate immune system, which is comprised of germ line encoded pathogen recognition receptors (PRRs). This PRR mediated system functions by specifically recognizing conserved structures of microbial molecules or products, known as microbial-associated molecular patterns (MAMPs), ultimately enabling transduction of signaling cascades, gene transcription and the development of a pro-inflammatory innate immune response. The intracellular PRRs nucleotide-binding oligomerization domain protein 1 (NOD1) and NOD2 will be the focus of this review. A brief overview of NOD1 and NOD2 and recent advances in the field regarding the intracellular location and mechanisms of NOD1 signaling will be discussed. These new findings have broadened our understanding of the mechanisms whereby NOD1 signaling results in the induction of the cellular degradation pathway of autophagy and the development of pro-inflammatory responses that activate the adaptive immune system. PMID:25801093

  18. Legionella pneumophila requires polyamines for optimal intracellular growth.

    PubMed

    Nasrallah, Gheyath K; Riveroll, Angela L; Chong, Audrey; Murray, Lois E; Lewis, P Jeffrey; Garduño, Rafael A

    2011-09-01

    The Gram-negative intracellular pathogen Legionella pneumophila replicates in a membrane-bound compartment known as the Legionella-containing vacuole (LCV), into which it abundantly releases its chaperonin, HtpB. To determine whether HtpB remains within the LCV or reaches the host cell cytoplasm, we infected U937 human macrophages and CHO cells with L. pneumophila expressing a translocation reporter consisting of the Bordetella pertussisa denylate cyclase fused to HtpB. These infections led to increased cyclic AMP levels, suggesting that HtpB reaches the host cell cytoplasm. To identify potential functions of cytoplasmic HtpB, we expressed it in the yeast Saccharomyces cerevisiae, where HtpB induced pseudohyphal growth. A yeast-two-hybrid screen showed that HtpB interacted with S-adenosylmethionine decarboxylase (SAMDC), an essential yeast enzyme (encoded by SPE2) that is required for polyamine biosynthesis. Increasing the copy number of SPE2 induced pseudohyphal growth in S. cerevisiae; thus, we speculated that (i) HtpB induces pseudohyphal growth by activating polyamine synthesis and (ii) L. pneumophila may require exogenous polyamines for growth. A pharmacological inhibitor of SAMDC significantly reduced L. pneumophila replication in L929 mouse cells and U937 macrophages, whereas exogenously added polyamines moderately favored intracellular growth, confirming that polyamines and host SAMDC activity promote L. pneumophila proliferation. Bioinformatic analysis revealed that most known enzymes required for polyamine biosynthesis in bacteria (including SAMDC) are absent in L. pneumophila, further suggesting a need for exogenous polyamines. We hypothesize that HtpB may function to ensure a supply of polyamines in host cells, which are required for the optimal intracellular growth of L. pneumophila. PMID:21742865

  19. Legionella pneumophilaRequires Polyamines for Optimal Intracellular Growth ?

    PubMed Central

    Nasrallah, Gheyath K.; Riveroll, Angela L.; Chong, Audrey; Murray, Lois E.; Lewis, P. Jeffrey; Garduño, Rafael A.

    2011-01-01

    The Gram-negative intracellular pathogen Legionella pneumophilareplicates in a membrane-bound compartment known as the Legionella-containing vacuole (LCV), into which it abundantly releases its chaperonin, HtpB. To determine whether HtpB remains within the LCV or reaches the host cell cytoplasm, we infected U937 human macrophages and CHO cells with L. pneumophilaexpressing a translocation reporter consisting of the Bordetella pertussisadenylate cyclase fused to HtpB. These infections led to increased cyclic AMP levels, suggesting that HtpB reaches the host cell cytoplasm. To identify potential functions of cytoplasmic HtpB, we expressed it in the yeast Saccharomyces cerevisiae, where HtpB induced pseudohyphal growth. A yeast-two-hybrid screen showed that HtpB interacted with S-adenosylmethionine decarboxylase (SAMDC), an essential yeast enzyme (encoded by SPE2) that is required for polyamine biosynthesis. Increasing the copy number of SPE2induced pseudohyphal growth in S. cerevisiae; thus, we speculated that (i) HtpB induces pseudohyphal growth by activating polyamine synthesis and (ii) L. pneumophilamay require exogenous polyamines for growth. A pharmacological inhibitor of SAMDC significantly reduced L. pneumophilareplication in L929 mouse cells and U937 macrophages, whereas exogenously added polyamines moderately favored intracellular growth, confirming that polyamines and host SAMDC activity promote L. pneumophilaproliferation. Bioinformatic analysis revealed that most known enzymes required for polyamine biosynthesis in bacteria (including SAMDC) are absent in L. pneumophila, further suggesting a need for exogenous polyamines. We hypothesize that HtpB may function to ensure a supply of polyamines in host cells, which are required for the optimal intracellular growth of L. pneumophila. PMID:21742865

  20. Glacial refugia in pathogens: European genetic structure of anther smut pathogens on Silene latifolia and Silene dioica.

    PubMed

    Vercken, Elodie; Fontaine, Michael C; Gladieux, Pierre; Hood, Michael E; Jonot, Odile; Giraud, Tatiana

    2010-01-01

    Climate warming is predicted to increase the frequency of invasions by pathogens and to cause the large-scale redistribution of native host species, with dramatic consequences on the health of domesticated and wild populations of plants and animals. The study of historic range shifts in response to climate change, such as during interglacial cycles, can help in the prediction of the routes and dynamics of infectious diseases during the impending ecosystem changes. Here we studied the population structure in Europe of two Microbotryum species causing anther smut disease on the plants Silene latifolia and Silene dioica. Clustering analyses revealed the existence of genetically distinct groups for the pathogen on S. latifolia, providing a clear-cut example of European phylogeography reflecting recolonization from southern refugia after glaciation. The pathogen genetic structure was congruent with the genetic structure of its host species S. latifolia, suggesting dependence of the migration pathway of the anther smut fungus on its host. The fungus, however, appeared to have persisted in more numerous and smaller refugia than its host and to have experienced fewer events of large-scale dispersal. The anther smut pathogen on S. dioica also showed a strong phylogeographic structure that might be related to more northern glacial refugia. Differences in host ecology probably played a role in these differences in the pathogen population structure. Very high selfing rates were inferred in both fungal species, explaining the low levels of admixture between the genetic clusters. The systems studied here indicate that migration patterns caused by climate change can be expected to include pathogen invasions that follow the redistribution of their host species at continental scales, but also that the recolonization by pathogens is not simply a mirror of their hosts, even for obligate biotrophs, and that the ecology of hosts and pathogen mating systems likely affects recolonization patterns. PMID:21187901

  1. Glacial Refugia in Pathogens: European Genetic Structure of Anther Smut Pathogens on Silene latifolia and Silene dioica

    PubMed Central

    Vercken, Elodie; Fontaine, Michael C.; Gladieux, Pierre; Hood, Michael E.; Jonot, Odile; Giraud, Tatiana

    2010-01-01

    Climate warming is predicted to increase the frequency of invasions by pathogens and to cause the large-scale redistribution of native host species, with dramatic consequences on the health of domesticated and wild populations of plants and animals. The study of historic range shifts in response to climate change, such as during interglacial cycles, can help in the prediction of the routes and dynamics of infectious diseases during the impending ecosystem changes. Here we studied the population structure in Europe of two Microbotryum species causing anther smut disease on the plants Silene latifolia and Silene dioica. Clustering analyses revealed the existence of genetically distinct groups for the pathogen on S. latifolia, providing a clear-cut example of European phylogeography reflecting recolonization from southern refugia after glaciation. The pathogen genetic structure was congruent with the genetic structure of its host species S. latifolia, suggesting dependence of the migration pathway of the anther smut fungus on its host. The fungus, however, appeared to have persisted in more numerous and smaller refugia than its host and to have experienced fewer events of large-scale dispersal. The anther smut pathogen on S. dioica also showed a strong phylogeographic structure that might be related to more northern glacial refugia. Differences in host ecology probably played a role in these differences in the pathogen population structure. Very high selfing rates were inferred in both fungal species, explaining the low levels of admixture between the genetic clusters. The systems studied here indicate that migration patterns caused by climate change can be expected to include pathogen invasions that follow the redistribution of their host species at continental scales, but also that the recolonization by pathogens is not simply a mirror of their hosts, even for obligate biotrophs, and that the ecology of hosts and pathogen mating systems likely affects recolonization patterns. PMID:21187901

  2. 31 CFR 225.3 - Pledge of Government obligations in lieu of a bond with surety or sureties.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Pledge of Government obligations in lieu of a bond with... ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.3 Pledge of Government obligations in lieu of a bond...

  3. 31 CFR 225.3 - Pledge of Government obligations in lieu of a bond with surety or sureties.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Pledge of Government obligations in lieu of a bond with... ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.3 Pledge of Government obligations in lieu of a bond...

  4. 31 CFR 225.3 - Pledge of Government obligations in lieu of a bond with surety or sureties.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Pledge of Government obligations in lieu of a bond with... ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.3 Pledge of Government obligations in lieu of a bond...

  5. 31 CFR 225.3 - Pledge of Government obligations in lieu of a bond with surety or sureties.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Pledge of Government obligations in lieu of a bond with... ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.3 Pledge of Government obligations in lieu of a bond...

  6. 31 CFR 225.3 - Pledge of Government obligations in lieu of a bond with surety or sureties.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Pledge of Government obligations in lieu of a bond with... ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.3 Pledge of Government obligations in lieu of a bond...

  7. 12 CFR 1.130 - Type II securities; guidelines for obligations issued for university and housing purposes.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...guidelines for obligations issued for university and housing purposes. 1.130 Section...guidelines for obligations issued for university and housing purposes. (a) Investment... An obligation issued for housing, university, or dormitory purposes is a Type...

  8. 31 CFR 1010.311 - Filing obligations for reports of transactions in currency.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...false Filing obligations for reports of transactions in currency...Finance (Continued) FINANCIAL CRIMES ENFORCEMENT NETWORK, DEPARTMENT...TREASURY GENERAL PROVISIONS Reports Required To Be Made § 1010.311 Filing obligations for reports of transactions in...

  9. 31 CFR 1010.311 - Filing obligations for reports of transactions in currency.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...false Filing obligations for reports of transactions in currency...Finance (Continued) FINANCIAL CRIMES ENFORCEMENT NETWORK, DEPARTMENT...TREASURY GENERAL PROVISIONS Reports Required To Be Made § 1010.311 Filing obligations for reports of transactions in...

  10. 31 CFR 1010.311 - Filing obligations for reports of transactions in currency.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...false Filing obligations for reports of transactions in currency...Finance (Continued) FINANCIAL CRIMES ENFORCEMENT NETWORK, DEPARTMENT...TREASURY GENERAL PROVISIONS Reports Required To Be Made § 1010.311 Filing obligations for reports of transactions in...

  11. 31 CFR 1010.311 - Filing obligations for reports of transactions in currency.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...false Filing obligations for reports of transactions in currency...Finance (Continued) FINANCIAL CRIMES ENFORCEMENT NETWORK, DEPARTMENT...TREASURY GENERAL PROVISIONS Reports Required To Be Made § 1010.311 Filing obligations for reports of transactions in...

  12. Hill-Burton Facilities Obligated to Provide Free or Reduced-Cost Health Care

    MedlinePLUS

    ... Facilities Obligated to Provide Free or Reduced-Cost Health Care Total Obligated Facilities: 152 (03/31/2015) No ... 463-7313 Outpatient Facility 120270 PFCA FL RURAL HEALTH CARE, INC 1213 STATE ROAD 20 INTERLACHEN 32148 386- ...

  13. 47 CFR 14.61 - Obligations with respect to internet browsers built into mobile phones.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... false Obligations with respect to internet browsers built into mobile phones...EQUIPMENT BY PEOPLE WITH DISABILITIES Internet Browsers Built Into Telephones Used With...14.61 Obligations with respect to internet browsers built into mobile phones....

  14. 47 CFR 14.61 - Obligations with respect to internet browsers built into mobile phones.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... false Obligations with respect to internet browsers built into mobile phones...EQUIPMENT BY PEOPLE WITH DISABILITIES Internet Browsers Built Into Telephones Used With...14.61 Obligations with respect to internet browsers built into mobile phones....

  15. 40 CFR 80.1407 - How are the Renewable Volume Obligations calculated?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...following formulas: (1) Cellulosic biofuel. RVOCB,i = (RFStdCB,i ...Renewable Volume Obligation for cellulosic biofuel for an obligated party for calendar year...RFStdCB,i = The standard for cellulosic biofuel for calendar year i, determined by...

  16. 40 CFR 80.1407 - How are the Renewable Volume Obligations calculated?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...following formulas: (1) Cellulosic biofuel. RVOCB,i = (RFStdCB,i ...Renewable Volume Obligation for cellulosic biofuel for an obligated party for calendar year...RFStdCB,i = The standard for cellulosic biofuel for calendar year i, determined by...

  17. 40 CFR 80.1407 - How are the Renewable Volume Obligations calculated?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...following formulas: (1) Cellulosic biofuel. RVOCB,i = (RFStdCB,i ...Renewable Volume Obligation for cellulosic biofuel for an obligated party for calendar year...RFStdCB,i = The standard for cellulosic biofuel for calendar year i, determined by...

  18. 24 CFR 811.110 - Refunding of obligations issued to finance Section 8 projects.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...false Refunding of obligations issued to finance Section 8 projects. 811.110 Section...110 Refunding of obligations issued to finance Section 8 projects. (a) This...savings and, if necessary, HUD will finance in refunding bond debt service...

  19. 24 CFR 811.110 - Refunding of obligations issued to finance Section 8 projects.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...false Refunding of obligations issued to finance Section 8 projects. 811.110 Section...110 Refunding of obligations issued to finance Section 8 projects. (a) This...savings and, if necessary, HUD will finance in refunding bond debt service...

  20. 24 CFR 811.110 - Refunding of obligations issued to finance Section 8 projects.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...false Refunding of obligations issued to finance Section 8 projects. 811.110 Section...110 Refunding of obligations issued to finance Section 8 projects. (a) This...savings and, if necessary, HUD will finance in refunding bond debt service...

  1. 24 CFR 811.110 - Refunding of obligations issued to finance Section 8 projects.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...false Refunding of obligations issued to finance Section 8 projects. 811.110 Section...110 Refunding of obligations issued to finance Section 8 projects. (a) This...savings and, if necessary, HUD will finance in refunding bond debt service...

  2. 12 CFR 617.7400 - What protections exist for borrowers who meet all loan obligations?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...What protections exist for borrowers who meet all loan obligations? 617.7400 Section...protections exist for borrowers who meet all loan obligations? (a) A qualified...additional collateral when the borrower has made all accrued payments of principal,...

  3. 20 CFR 655.1305 - Assurances and obligations of H-2A employers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Assurances and obligations of H-2A employers. 655.1305 Section 655.1305 Employees' Benefits EMPLOYMENT AND TRAINING...Employment in the United States (H-2A Workers) § 655.1305 Assurances and obligations of H-2A...

  4. 20 CFR 655.1305 - Assurances and obligations of H-2A employers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Assurances and obligations of H-2A employers. 655.1305 Section 655.1305 Employees' Benefits EMPLOYMENT AND TRAINING...Employment in the United States (H-2A Workers) § 655.1305 Assurances and obligations of H-2A...

  5. 20 CFR 655.1305 - Assurances and obligations of H-2A employers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Assurances and obligations of H-2A employers. 655.1305 Section 655.1305 Employees' Benefits EMPLOYMENT AND TRAINING...Employment in the United States (H-2A Workers) § 655.1305 Assurances and obligations of H-2A...

  6. 20 CFR 655.1305 - Assurances and obligations of H-2A employers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Assurances and obligations of H-2A employers. 655.1305 Section 655.1305 Employees' Benefits EMPLOYMENT AND TRAINING...Employment in the United States (H-2A Workers) § 655.1305 Assurances and obligations of H-2A...

  7. 20 CFR 655.1305 - Assurances and obligations of H-2A employers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Assurances and obligations of H-2A employers. 655.1305 Section 655.1305 Employees' Benefits EMPLOYMENT AND TRAINING...Employment in the United States (H-2A Workers) § 655.1305 Assurances and obligations of H-2A...

  8. 20 CFR 655.135 - Assurances and obligations of H-2A employers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Assurances and obligations of H-2A employers. 655.135 Section 655.135 Employees' Benefits EMPLOYMENT AND TRAINING...Temporary Employment Certification Filing Procedures § 655.135 Assurances and obligations of H-2A...

  9. 43 CFR 9.11 - What are the Secretary's obligations in interstate situations?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Secretary's obligations in interstate situations? 9.11 Section 9.11 Public Lands: Interior Office of the Secretary...DEPARTMENT OF THE INTERIOR PROGRAMS AND ACTIVITIES § 9.11 What are the Secretary's obligations in...

  10. 43 CFR 9.11 - What are the Secretary's obligations in interstate situations?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Secretary's obligations in interstate situations? 9.11 Section 9.11 Public Lands: Interior Office of the Secretary...DEPARTMENT OF THE INTERIOR PROGRAMS AND ACTIVITIES § 9.11 What are the Secretary's obligations in...

  11. 43 CFR 9.11 - What are the Secretary's obligations in interstate situations?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Secretary's obligations in interstate situations? 9.11 Section 9.11 Public Lands: Interior Office of the Secretary...DEPARTMENT OF THE INTERIOR PROGRAMS AND ACTIVITIES § 9.11 What are the Secretary's obligations in...

  12. 43 CFR 9.11 - What are the Secretary's obligations in interstate situations?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Secretary's obligations in interstate situations? 9.11 Section 9.11 Public Lands: Interior Office of the Secretary...DEPARTMENT OF THE INTERIOR PROGRAMS AND ACTIVITIES § 9.11 What are the Secretary's obligations in...

  13. 43 CFR 9.11 - What are the Secretary's obligations in interstate situations?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Secretary's obligations in interstate situations? 9.11 Section 9.11 Public Lands: Interior Office of the Secretary...DEPARTMENT OF THE INTERIOR PROGRAMS AND ACTIVITIES § 9.11 What are the Secretary's obligations in...

  14. 26 CFR 1.662(a)-4 - Amounts used in discharge of a legal obligation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Amounts used in discharge of a legal obligation. 1...662(a)-4 Amounts used in discharge of a legal obligation. Any...instrument, is used in full or partial discharge or satisfaction of a...

  15. 26 CFR 1.662(a)-4 - Amounts used in discharge of a legal obligation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false Amounts used in discharge of a legal obligation. 1...662(a)-4 Amounts used in discharge of a legal obligation. Any...instrument, is used in full or partial discharge or satisfaction of a...

  16. 26 CFR 1.662(a)-4 - Amounts used in discharge of a legal obligation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Amounts used in discharge of a legal obligation. 1...662(a)-4 Amounts used in discharge of a legal obligation. Any...instrument, is used in full or partial discharge or satisfaction of a...

  17. 26 CFR 1.662(a)-4 - Amounts used in discharge of a legal obligation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Amounts used in discharge of a legal obligation. 1...662(a)-4 Amounts used in discharge of a legal obligation. Any...instrument, is used in full or partial discharge or satisfaction of a...

  18. 18 CFR 367.2430 - Account 243, Obligations under capital leases-Current.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...243, Obligations under capital leases-Current. 367.2430 Section 367.2430 ...ACT Balance Sheet Chart of Accounts Current and Accrued Liabilities § 367.2430...Obligations under capital leases—Current. This account must include the...

  19. 18 CFR 367.2430 - Account 243, Obligations under capital leases-Current.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...243, Obligations under capital leases-Current. 367.2430 Section 367.2430 ...ACT Balance Sheet Chart of Accounts Current and Accrued Liabilities § 367.2430...Obligations under capital leases—Current. This account must include the...

  20. 29 CFR 37.29 - What are a recipient's obligations to disseminate its equal opportunity policy?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...obligations to disseminate its equal opportunity policy? 37.29 Section...OF THE NONDISCRIMINATION AND EQUAL OPPORTUNITY PROVISIONS OF THE WORKFORCE...obligations to disseminate its equal opportunity policy? (a) A...

  1. 40 CFR 80.1407 - How are the Renewable Volume Obligations calculated?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...following formulas: (1) Cellulosic biofuel. RVOCB,i = (RFStdCB,i ...Renewable Volume Obligation for cellulosic biofuel for an obligated party for calendar year...RFStdCB,i = The standard for cellulosic biofuel for calendar year i, determined by...

  2. 40 CFR 80.1407 - How are the Renewable Volume Obligations calculated?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...following formulas: (1) Cellulosic biofuel. RVOCB,i = (RFStdCB,i ...Renewable Volume Obligation for cellulosic biofuel for an obligated party for calendar year...RFStdCB,i = The standard for cellulosic biofuel for calendar year i, determined by...

  3. 21 CFR 312.52 - Transfer of obligations to a contract research organization.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Transfer of obligations to a contract research organization. 312.52 Section...Transfer of obligations to a contract research organization. (a) A sponsor...forth in this part to a contract research organization. Any such...

  4. 40 CFR 152.97 - Rights and obligations of data submitters.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Rights and obligations of data submitters. 152.97 Section 152...PROCEDURES Procedures To Ensure Protection of Data Submitters' Rights § 152.97 Rights and obligations of data submitters. (a) Right to be...

  5. 40 CFR 152.97 - Rights and obligations of data submitters.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Rights and obligations of data submitters. 152.97 Section 152...PROCEDURES Procedures To Ensure Protection of Data Submitters' Rights § 152.97 Rights and obligations of data submitters. (a) Right to be...

  6. 40 CFR 152.97 - Rights and obligations of data submitters.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Rights and obligations of data submitters. 152.97 Section 152...PROCEDURES Procedures To Ensure Protection of Data Submitters' Rights § 152.97 Rights and obligations of data submitters. (a) Right to be...

  7. Intracellular signalling during neutrophil recruitment

    PubMed Central

    Mócsai, Attila; Walzog, Barbara; Lowell, Clifford A.

    2015-01-01

    Recruitment of leucocytes such as neutrophils to the extravascular space is a critical step of the inflammation process and plays a major role in the development of various diseases including several cardiovascular diseases. Neutrophils themselves play a very active role in that process by sensing their environment and responding to the extracellular cues by adhesion and de-adhesion, cellular shape changes, chemotactic migration, and other effector functions of cell activation. Those responses are co-ordinated by a number of cell surface receptors and their complex intracellular signal transduction pathways. Here, we review neutrophil signal transduction processes critical for recruitment to the site of inflammation. The two key requirements for neutrophil recruitment are the establishment of appropriate chemoattractant gradients and the intrinsic ability of the cells to migrate along those gradients. We will first discuss signalling steps required for sensing extracellular chemoattractants such as chemokines and lipid mediators and the processes (e.g. PI3-kinase pathways) leading to the translation of extracellular chemoattractant gradients to polarized cellular responses. We will then discuss signal transduction by leucocyte adhesion receptors (e.g. tyrosine kinase pathways) which are critical for adhesion to, and migration through the vessel wall. Finally, additional neutrophil signalling pathways with an indirect effect on the neutrophil recruitment process, e.g. through modulation of the inflammatory environment, will be discussed. Mechanistic understanding of these pathways provide better understanding of the inflammation process and may point to novel therapeutic strategies for controlling excessive inflammation during infection or tissue damage. PMID:25998986

  8. Intracellular signaling of cardiac fibroblasts.

    PubMed

    Roche, Patricia L; Filomeno, Krista L; Bagchi, Rushita A; Czubryt, Michael P

    2015-03-01

    Long regarded as a mere accessory cell for the cardiomyocyte, the cardiac fibroblast is now recognized as a critical determinant of cardiac function in health and disease. A recent renaissance in fibroblast-centered research has fostered a better understanding than ever before of the biology of fibroblasts and their contractile counterparts, myofibroblasts. While advanced methodological approaches, including transgenics, lineage fate mapping, and improved cell marker identification have helped to facilitate this new work, the primary driver is arguably the contribution of myofibroblasts to cardiac pathophysiology including fibrosis and arrhythmogenesis. Fibrosis is a natural sequel to numerous common cardiac pathologies including myocardial infarction and hypertension, and typically exacerbates cardiovascular disease and progression to heart failure, yet no therapies currently exist to specifically target fibrosis. The regulatory processes and intracellular signaling pathways governing fibroblast and myofibroblast behavior thus represent important points of inquiry for the development of antifibrotic treatments. While steady progress is being made in uncovering the signaling pathways specific for cardiac fibroblast function (including proliferation, phenotype conversion, and matrix synthesis), much of what is currently known of fibroblast signaling mechanisms is derived from noncardiac fibroblast populations. Given the heterogeneity of fibroblasts across tissues, this dearth of information further underscores the need for progress in cardiac fibroblast biological research. © 2015 American Physiological Society. Compr Physiol 5: 721-760, 2015. PMID:25880511

  9. Identification of a Novel Small Non-Coding RNA Modulating the Intracellular Survival of Brucella melitensis

    PubMed Central

    Wang, Yufei; Ke, Yuehua; Xu, Jie; Wang, Ligui; Wang, Tongkun; Liang, Hui; Zhang, Wei; Gong, Chunli; Yuan, Jiuyun; Zhuang, Yubin; An, Chang; Lei, Shuangshuang; Du, Xinying; Wang, Zhoujia; Li, Wenna; Yuan, Xitong; Huang, Liuyu; Yang, Xiaoli; Chen, Zeliang

    2015-01-01

    Bacterial small non-coding RNAs (sRNAs) are gene expression modulators respond to environmental changes, stressful conditions, and pathogenesis. In this study, by using a combined bioinformatic and experimental approach, eight novel sRNA genes were identified in intracellular pathogen Brucella melitensis. BSR0602, one sRNA that was highly induced in stationary phase, was further examined and found to modulate the intracellular survival of B. melitensis. BSR0602 was present at very high levels in vitro under stresses similar to those encountered during infection in host macrophages. Furthermore, BSR0602 was found to be highly expressed in the spleens of infected mice, suggesting its potential role in the control of pathogenesis. BSR0602 targets the mRNAs coding for gntR, a global transcriptional regulator, which is required for B. melitensis virulence. Overexpression of BSR0602 results in distinct reduction in the gntR mRNA level. B. melitensis with high level of BSR0602 is defective in bacteria intracellular survival in macrophages and defective in growth in the spleens of infected mice. Therefore, BSR0602 may directly inhibit the expression of gntR, which then impairs Brucellae intracellular survival and contributes to Brucella infection. Our findings suggest that BSR0602 is responsible for bacterial adaptation to stress conditions and thus modulate B. melitensis intracellular survival. PMID:25852653

  10. Identification of a Novel Small Non-Coding RNA Modulating the Intracellular Survival of Brucella melitensis.

    PubMed

    Wang, Yufei; Ke, Yuehua; Xu, Jie; Wang, Ligui; Wang, Tongkun; Liang, Hui; Zhang, Wei; Gong, Chunli; Yuan, Jiuyun; Zhuang, Yubin; An, Chang; Lei, Shuangshuang; Du, Xinying; Wang, Zhoujia; Li, Wenna; Yuan, Xitong; Huang, Liuyu; Yang, Xiaoli; Chen, Zeliang

    2015-01-01

    Bacterial small non-coding RNAs (sRNAs) are gene expression modulators respond to environmental changes, stressful conditions, and pathogenesis. In this study, by using a combined bioinformatic and experimental approach, eight novel sRNA genes were identified in intracellular pathogen Brucella melitensis. BSR0602, one sRNA that was highly induced in stationary phase, was further examined and found to modulate the intracellular survival of B. melitensis. BSR0602 was present at very high levels in vitro under stresses similar to those encountered during infection in host macrophages. Furthermore, BSR0602 was found to be highly expressed in the spleens of infected mice, suggesting its potential role in the control of pathogenesis. BSR0602 targets the mRNAs coding for gntR, a global transcriptional regulator, which is required for B. melitensis virulence. Overexpression of BSR0602 results in distinct reduction in the gntR mRNA level. B. melitensis with high level of BSR0602 is defective in bacteria intracellular survival in macrophages and defective in growth in the spleens of infected mice. Therefore, BSR0602 may directly inhibit the expression of gntR, which then impairs Brucellae intracellular survival and contributes to Brucella infection. Our findings suggest that BSR0602 is responsible for bacterial adaptation to stress conditions and thus modulate B. melitensis intracellular survival. PMID:25852653

  11. Take the tube: remodelling of the endosomal system by intracellular Salmonella enterica.

    PubMed

    Liss, Viktoria; Hensel, Michael

    2015-05-01

    Salmonella enterica is a facultative intracellular pathogen residing in a unique host cell-derived membrane compartment, termed Salmonella-containing vacuole or SCV. By the activity of effector proteins translocated by the SPI2-endoced type III secretion system (T3SS), the biogenesis of the SCV is manipulated to generate a habitat permissive for intracellular proliferation. By taking control of the host cell vesicle fusion machinery, intracellular Salmonella creates an extensive interconnected system of tubular membranes arising from vesicles of various origins, collectively termed Salmonella-induced tubules (SIT). Recent work investigated the dynamic properties of these manipulations. New host cell targets of SPI2-T3SS effector proteins were identified. By applying combinations of live cell imaging and ultrastructural analyses, the detailed organization of membrane compartments inhabited and modified by intracellular Salmonella is now available. These studies provided unexpected new details on the intracellular environments of Salmonella. For example, one kind of SIT, the LAMP1-positive Salmonella-induced filaments (SIF), are composed of double-membrane tubules, with an inner lumen containing host cell cytosol and cytoskeletal filaments, and an outer lumen containing endocytosed cargo. The novel findings call for new models for the biogenesis of SCV and SIT and give raise to many open questions we discuss in this review. PMID:25802001

  12. Genome reduction in prokaryotic obligatory intracellular parasites of humans: a comparative analysis.

    PubMed

    Sakharkar, Kishore R; Dhar, Pawan Kumar; Chow, Vincent T K

    2004-11-01

    Obligatory intracellular parasites have undergone significant genome reduction by gene loss over time in the context of their obligate associations with the host. The flux, streamlining and elimination of genes in these genomes constitute a selective and ongoing process. Comparative analyses of five completely sequenced obligatory intracellular parasite genomes reveal that these genomes display marked similarities in patterns of protein length and frequency distribution, with substantial sharing of a 'backbone genome'. From category distribution based on the database of cluster of orthologous groups of proteins (COG), it is clear that habitat is a major factor contributing to genome reduction. It is also observed that, in all five obligatory intracellular parasites, the reduction in number of genes/proteins is greater for proteins with lengths of 200-600 amino acids. These comparative analyses highlight that gene loss is function-dependent, but is independent of protein length. These comparisons enhance our knowledge of the forces that drive the extreme specialization of the bacteria and their association with the host. PMID:15545414

  13. Signaling During Pathogen Infection

    NSDL National Science Digital Library

    Sylvia Munter (University of Heidelberg Medical School; Department of Parasitology REV)

    2006-05-16

    Pathogens infect almost every living organism. In animals, including humans, the diversity of pathogens ranges from viruses, bacteria, and unicellular parasites to complex fungi, worms, and arthropods. Because pathogens have coevolved with their hosts and have sometimes been coopted as symbionts or commensals, each pathogen/host pair represents a striking success story of survival that reflects the biological complexity of both parties. All invading microorganisms face similar problems, such as gaining access to their host, achieving successful replication, and spreading to a similar or different host. It is therefore not surprising that many different pathogens target similar organs, cell types, and even molecules to achieve their goals. However, no two microbial parasites appear to be completely alike. Although they often target similar signaling networks, they do so in subtly different ways to achieve the desired outcome. This review has eight figures, three movies, and 139 citations and emphasizes two well-established signaling pathways that are often activated during the interaction of different pathogens with their host cells. It illustrates a small part of how the dissection of host/pathogen interactions can reveal, on a molecular scale, a nature shaped by evolutionary forces that can rival the great descriptions of our macroscopic world.

  14. Nod1 responds to peptidoglycan delivered by the Helicobacter pylori cag pathogenicity island

    Microsoft Academic Search

    Jérôme Viala; Catherine Chaput; Ivo G Boneca; Ana Cardona; Stephen E Girardin; Anthony P Moran; Rafika Athman; Sylvie Mémet; Michel R Huerre; Anthony J Coyle; Peter S DiStefano; Philippe J Sansonetti; Agnès Labigne; John Bertin; Dana J Philpott; Richard L Ferrero

    2004-01-01

    Epithelial cells can respond to conserved bacterial products that are internalized after either bacterial invasion or liposome treatment of cells. We report here that the noninvasive Gram-negative pathogen Helicobacter pylori was recognized by epithelial cells via Nod1, an intracellular pathogen-recognition molecule with specificity for Gram-negative peptidoglycan. Nod1 detection of H. pylori depended on the delivery of peptidoglycan to host cells

  15. 30 CFR 243.8 - When will MMS suspend my obligation to comply with an order?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false When will MMS suspend my obligation to comply with an...General Provisions § 243.8 When will MMS suspend my obligation to comply with an...require payment of a specified amount, MMS will suspend your obligation to comply...

  16. 31 CFR 225.4 - Pledge of book-entry Government obligations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Pledge of book-entry Government obligations. 225.4 Section 225...SERVICE ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.4 Pledge of book-entry Government obligations. (a)...

  17. 31 CFR 225.4 - Pledge of book-entry Government obligations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Pledge of book-entry Government obligations. 225.4 Section 225...SERVICE ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.4 Pledge of book-entry Government obligations. (a)...

  18. 31 CFR 225.4 - Pledge of book-entry Government obligations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Pledge of book-entry Government obligations. 225.4 Section 225...SERVICE ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.4 Pledge of book-entry Government obligations. (a)...

  19. 31 CFR 225.4 - Pledge of book-entry Government obligations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Pledge of book-entry Government obligations. 225.4 Section 225...SERVICE ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.4 Pledge of book-entry Government obligations. (a)...

  20. 31 CFR 225.4 - Pledge of book-entry Government obligations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Pledge of book-entry Government obligations. 225.4 Section 225...SERVICE ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.4 Pledge of book-entry Government obligations. (a)...

  1. Spatial aspects of intracellular information processing.

    PubMed

    Kinkhabwala, Ali; Bastiaens, Philippe I H

    2010-02-01

    The computational properties of intracellular biochemical networks, for which the cell is assumed to be a 'well-mixed' reactor, have already been widely characterized. What has so far not received systematic treatment is the important role of space in many intracellular computations. Spatial network computations can be divided into two broad categories: those required for essential spatial processes (e.g. polarization, chemotaxis, division, and development) and those for which space is simply used as an extra dimension to expand the computational power of the network. Several pertinent recent examples of each category are discussed that illustrate the often conceptually subtle role of space in the processing of intracellular information. PMID:20096560

  2. Stochastic resonance in an intracellular genetic perceptron.

    PubMed

    Bates, Russell; Blyuss, Oleg; Zaikin, Alexey

    2014-03-01

    Intracellular genetic networks are more intelligent than was first assumed due to their ability to learn. One of the manifestations of this intelligence is the ability to learn associations of two stimuli within gene-regulating circuitry: Hebbian-type learning within the cellular life. However, gene expression is an intrinsically noisy process; hence, we investigate the effect of intrinsic and extrinsic noise on this kind of intracellular intelligence. We report a stochastic resonance in an intracellular associative genetic perceptron, a noise-induced phenomenon, which manifests itself in noise-induced increase of response in efficiency after the learning event under the conditions of optimal stochasticity. PMID:24730883

  3. Drug target identification in intracellular and extracellular protozoan parasites.

    PubMed

    Müller, Joachim; Hemphill, Andrew

    2011-01-01

    The increasing demand for novel anti-parasitic drugs due to resistance formation to well-established chemotherapeutically important compounds has increased the demands for a better understanding of the mechanism(s) of action of existing drugs and of drugs in development. While different approaches have been developed to identify the targets and thus mode of action of anti-parasitic compounds, it has become clear that many drugs act not only on one, but possibly several parasite molecules or even pathways. Ideally, these targets are not present in any cells of the host. In the case of apicomplexan parasites, the unique apicoplast, provides a suitable target for compounds binding to DNA or ribosomal RNA of prokaryotic origin. In the case of intracellular pathogens, a given drug might not only affect the pathogen by directly acting on parasite-associated targets, but also indirectly, by altering the host cell physiology. This in turn could affect the parasite development and lead to parasite death. In this review, we provide an overview of strategies for target identification, and present examples of selected drug targets, ranging from proteins to nucleic acids to intermediary metabolism. PMID:21619514

  4. Coxiella burnetii effector proteins that localize to the parasitophorous vacuole membrane promote intracellular replication.

    PubMed

    Larson, Charles L; Beare, Paul A; Voth, Daniel E; Howe, Dale; Cockrell, Diane C; Bastidas, Robert J; Valdivia, Raphael H; Heinzen, Robert A

    2015-02-01

    The intracellular bacterial pathogen Coxiella burnetii directs biogenesis of a parasitophorous vacuole (PV) that acquires host endolysosomal components. Formation of a PV that supports C. burnetii replication requires a Dot/Icm type 4B secretion system (T4BSS) that delivers bacterial effector proteins into the host cell cytosol. Thus, a subset of T4BSS effectors are presumed to direct PV biogenesis. Recently, the PV-localized effector protein CvpA was found to promote C. burnetii intracellular growth and PV expansion. We predict additional C. burnetii effectors localize to the PV membrane and regulate eukaryotic vesicle trafficking events that promote pathogen growth. To identify these vacuolar effector proteins, a list of predicted C. burnetii T4BSS substrates was compiled using bioinformatic criteria, such as the presence of eukaryote-like coiled-coil domains. Adenylate cyclase translocation assays revealed 13 proteins were secreted in a Dot/Icm-dependent fashion by C. burnetii during infection of human THP-1 macrophages. Four of the Dot/Icm substrates, termed Coxiella vacuolar protein B (CvpB), CvpC, CvpD, and CvpE, labeled the PV membrane and LAMP1-positive vesicles when ectopically expressed as fluorescently tagged fusion proteins. C. burnetii ?cvpB, ?cvpC, ?cvpD, and ?cvpE mutants exhibited significant defects in intracellular replication and PV formation. Genetic complementation of the ?cvpD and ?cvpE mutants rescued intracellular growth and PV generation, whereas the growth of C. burnetii ?cvpB and ?cvpC was rescued upon cohabitation with wild-type bacteria in a common PV. Collectively, these data indicate C. burnetii encodes multiple effector proteins that target the PV membrane and benefit pathogen replication in human macrophages. PMID:25422265

  5. Introduction to Pathogenic Bacteria

    Microsoft Academic Search

    Tracey Elizabeth Love; Barbara Jones

    This chapter is a brief introduction to pathogenic microorganisms and also discusses virulence factors. An understanding of\\u000a virulence factors is important, as they represent potential targets for the detection of microbial pathogens. Sources and\\u000a routes of infection are also briefly discussed with reference to specific examples. There are a number of ways in which infection\\u000a could be acquired, including via

  6. Human Pathogen Importation Importing "Human" Pathogens from Outside Canada

    E-print Network

    Human Pathogen Importation Importing "Human" Pathogens from Outside Canada 1) Permits are not required for Risk Group 1 materals. If the material is deemed to be non- pathogenic, a courtesy notice may is required from PHAC*, please go to the PHAC website at http://www.phac- aspc.gc.ca/ols-bsl/pathogen

  7. BTI Pathogen Use Committee BTI Pathogen Use Form

    E-print Network

    Pawlowski, Wojtek

    BTI Pathogen Use Committee 4/7/04 1 BTI Pathogen Use Form Date Submitted: Date Received by PUC for space, if appropriate. 1. Are you planning to use recombinant pathogens in the BTI Plant Growth facilities? Yes No If yes, provide permit # of approved IBC r DNA MUA and attach copy. 2. List all pathogens

  8. Nanoparticles for intracellular-targeted drug delivery

    NASA Astrophysics Data System (ADS)

    Paulo, Cristiana S. O.; Pires das Neves, Ricardo; Ferreira, Lino S.

    2011-12-01

    Nanoparticles (NPs) are very promising for the intracellular delivery of anticancer and immunomodulatory drugs, stem cell differentiation biomolecules and cell activity modulators. Although initial studies in the area of intracellular drug delivery have been performed in the delivery of DNA, there is an increasing interest in the use of other molecules to modulate cell activity. Herein, we review the latest advances in the intracellular-targeted delivery of short interference RNA, proteins and small molecules using NPs. In most cases, the drugs act at different cellular organelles and therefore the drug-containing NPs should be directed to precise locations within the cell. This will lead to the desired magnitude and duration of the drug effects. The spatial control in the intracellular delivery might open new avenues to modulate cell activity while avoiding side-effects.

  9. A bacterial siren song: intimate interactions between neutrophils and pathogenic Neisseria

    PubMed Central

    Criss, Alison K.; Seifert, H. Steven

    2012-01-01

    Preface Neisseria gonorrhoeae and Neisseria meningitidis are Gram-negative bacterial pathogens that are exquisitely adapted for growth at human mucosal surfaces and for efficient transmission between hosts. One factor that is essential to neisserial pathogenesis is the interaction between the bacteria and neutrophils, which are recruited in high numbers during infection. Although this vigorous host response could simply reflect effective immune recognition of the bacteria, there is mounting evidence that in fact these obligate human pathogens manipulate the innate immune response to promote infectious processes. This Review summarizes the mechanisms used by pathogenic neisseriae to resist and modulate the antimicrobial activities of neutrophils. It also details some of the major outstanding questions about the Neisseria–neutrophil relationship and proposes potential benefits of this relationship for the pathogen. PMID:22290508

  10. Porphyromonas gingivalis Evasion of Autophagy and Intracellular Killing by Human Myeloid Dendritic Cells Involves DC-SIGN-TLR2 Crosstalk

    PubMed Central

    El-Awady, Ahmed R.; Miles, Brodie; Scisci, Elizabeth; Kurago, Zoya B.; Palani, Chithra D.; Arce, Roger M.; Waller, Jennifer L.; Genco, Caroline A.; Slocum, Connie; Manning, Matthew; Schoenlein, Patricia V.; Cutler, Christopher W.

    2015-01-01

    Signaling via pattern recognition receptors (PRRs) expressed on professional antigen presenting cells, such as dendritic cells (DCs), is crucial to the fate of engulfed microbes. Among the many PRRs expressed by DCs are Toll-like receptors (TLRs) and C-type lectins such as DC-SIGN. DC-SIGN is targeted by several major human pathogens for immune-evasion, although its role in intracellular routing of pathogens to autophagosomes is poorly understood. Here we examined the role of DC-SIGN and TLRs in evasion of autophagy and survival of Porphyromonas gingivalis in human monocyte-derived DCs (MoDCs). We employed a panel of P. gingivalis isogenic fimbriae deficient strains with defined defects in Mfa-1 fimbriae, a DC-SIGN ligand, and FimA fimbriae, a TLR2 agonist. Our results show that DC-SIGN dependent uptake of Mfa1+P. gingivalis strains by MoDCs resulted in lower intracellular killing and higher intracellular content of P. gingivalis. Moreover, Mfa1+P. gingivalis was mostly contained within single membrane vesicles, where it survived intracellularly. Survival was decreased by activation of TLR2 and/or autophagy. Mfa1+P. gingivalis strain did not induce significant levels of Rab5, LC3-II, and LAMP1. In contrast, P. gingivalis uptake through a DC-SIGN independent manner was associated with early endosomal routing through Rab5, increased LC3-II and LAMP-1, as well as the formation of double membrane intracellular phagophores, a characteristic feature of autophagy. These results suggest that selective engagement of DC-SIGN by Mfa-1+P. gingivalis promotes evasion of antibacterial autophagy and lysosome fusion, resulting in intracellular persistence in myeloid DCs; however TLR2 activation can overcome autophagy evasion and pathogen persistence in DCs. PMID:25679217

  11. US arms control obligations under the Non-Proliferation Treaty

    SciTech Connect

    Not Available

    1986-06-27

    Article VI of the 1968 Non-Proliferation Treaty (NPT) obligates the nuclear weapon states parties to the Treaty ''to pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race, ... to nuclear disarmament, and on a treaty on general and complete disarmament under strict and effective international control.'' The preamble to the NPT recalls the 1963 Limited Test Ban Treaty ''determination ... to achieve the discontinuance of ... explosions.'' These provisions are interpreted by a majority of the non-nuclear weapon states parties to the Treaty as an obligation of the nuclear weapon states parties to the Treaty to pursue a comprehensive test ban (CTB). However, a review of the history of the NPT negotiations and US ratification proceedings makes clear that the NPT imposes no legal obligation on the US to pursue a CTB. The US did not make a one-to-one correspondence between Article VI and any specific arms control measure; to the contrary, the US argued successfully that such a connection (to any specific measure) would be pernicious to the attempt to achieve agreement on the NPT. This interpretation, which was sustained through the negotiations and the ratification proceedings, still reflects the limits of the legal obligations the US has accepted. But, in the absence of progress on other arms control measures, which would relieve the pressure for a CTB, the majority interpretation creates political difficulties for the US and could threaten the NPT regime in the future. These problems highlight the need for the US to better defend its compliance with Article VI and to develop a long-term strategy that will permit necessary testing while assuring the survival of the NPT regime in effective form.

  12. Association between competition and obligate mutualism in a chemostat.

    PubMed

    El Hajji, Miled; Harmand, Jérôme; Chaker, Hédia; Lobry, Claude

    2009-11-01

    In this paper, we consider a simple chemostat model involving two obligate mutualistic species feeding on a limiting substrate. Systems of differential equations are proposed as models of this association. A detailed qualitative analysis is carried out. We show the existence of a domain of coexistence, which is a set of initial conditions in which both species survive. We demonstrate, under certain supplementary assumptions, the uniqueness of the stable equilibrium point which corresponds to the coexistence of the two species. PMID:22880965

  13. Price Regulation and Public Service Obligations under International Arbitrage

    Microsoft Academic Search

    Giorgio Matteucci; Pierfrancesco Reverberi

    2005-01-01

    National regulation generates price differentials between countries stimulating arbitrage by international distributors. Harmed manufacturers counteract using vertical price-squeeze or non-price discrimination. We show that: (i) either under regulatory commitment or discretion, there are non-linear relationships between technology\\/market conditions and the first-mover’s pricing strategy; (ii) public service obligations on distributors allow regulators to manipulate parallel exports so as to improve national

  14. Intracellular Vibrio parahaemolyticus Escapes the Vacuole and Establishes a Replicative Niche in the Cytosol of Epithelial Cells

    PubMed Central

    de Souza Santos, Marcela

    2014-01-01

    ABSTRACT Vibrio parahaemolyticus is a globally disseminated Gram-negative marine bacterium and the leading cause of seafood-borne acute gastroenteritis. Pathogenic bacterial isolates encode two type III secretion systems (T3SS), with the second system (T3SS2) considered the main virulence factor in mammalian hosts. For many decades, V. parahaemolyticus has been studied as an exclusively extracellular bacterium. However, the recent characterization of the T3SS2 effector protein VopC has suggested that this pathogen has the ability to invade, survive, and replicate within epithelial cells. Herein, we characterize this intracellular lifestyle in detail. We show that following internalization, V. parahaemolyticus is contained in vacuoles that develop into early endosomes, which subsequently mature into late endosomes. V. parahaemolyticus then escapes into the cytoplasm prior to vacuolar fusion with lysosomes. Vacuolar acidification is an important trigger for this escape. The cytoplasm serves as the pathogen’s primary intracellular replicative niche; cytosolic replication is rapid and robust, with cells often containing over 150 bacteria by the time of cell lysis. These results show how V. parahaemolyticus successfully establishes an intracellular lifestyle that could contribute to its survival and dissemination during infection. PMID:25205094

  15. Floral scents repel facultative flower visitors, but attract obligate ones

    PubMed Central

    Junker, Robert R.; Blüthgen, Nico

    2010-01-01

    Background and Aims Biological mutualisms rely on communication between partners, but also require protective measures against exploitation. Animal-pollinated flowers need to attract pollinators but also to avoid conflicts with antagonistic consumers. The view of flower visitors as mutualistic and antagonistic agents considers primarily the plants' interest. A classification emphasizing the consumer's point of view, however, may be more useful when considering animal's adaptations to flower visits which may include a tolerance against defensive floral scent compounds. Methods In a meta-analysis covering 18 studies on the responses of animals to floral scents, the animals were assigned to the categories of obligate and facultative flower visitors which considers their dependency on floral resources. Their responses on floral scents were compared. Key Results On average, obligate flower visitors, often corresponding to pollinators, were attracted to floral scent compounds. In contrast, facultative and mainly antagonistic visitors were strongly repelled by floral scents. The findings confirm that floral scents have a dual function both as attractive and defensive cues. Conclusions Whether an animal depends on floral resources determines its response to these signals, suggesting that obligate flower visitors evolved a tolerance against primarily defensive compounds. Therefore, floral scent bouquets in conjunction with nutritious rewards may solve the conflicting tasks of attracting mutualists while repelling antagonists. PMID:20228087

  16. Intracellular biopotentials during static extracellular stimulation.

    PubMed

    Klee, M

    1973-08-01

    Two properties of the intracellular potentials and electric fields resulting from static extracellular stimulation are obtained for arbitrarily shaped cells. First, the values of intracellular potential are shown to be bounded by the maximum and minimum values of extracellular potential on the surface of the cell. Second, the volume average of the magnitude of intracellular electric field is shown to have an upper bound given by the ratio of the magnitude of the largest extracellular potential difference on the surface of the cell to a generalized length constant lambda = [sigma(intra)V(cell)/(sigma(memb)A(cell))](1/2), where V(cell) and A(cell) are the volume and surface area of the cell, sigma(intra) is the intracellular conductivity (reciprocal ohms per centimeter), and sigma(memb) is the membrane conductivity (reciprocal ohms per square centimeter). The use of the upper bound on the volume average of the magnitude of intracellular electric field as an estimate for intracellular isopotentiality is discussed and the use of the generalized length constant for electrically describing arbitrary cells is illustrated for cylindrical- and spheroidal-shaped cells. PMID:4726882

  17. Will the package contain pathogens

    E-print Network

    Will the package contain pathogens OR dry ice ? Is the material considered hazardous by the DOT? Do ? NO NO YES YES Pack and ship. If you have identified any hazardous pathogenic substances, ensure you take EHS to a location outside of the US, and: - The materials are pathogens listed on Stanford's Dual Use Pathogen List

  18. A comprehensive Prunus pathogen array

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A comprehensive pathogen array was developed for the detection of pathogens of many major crops in the Prunus genus. The APS disease lists for peach, plum, apricot and cherry were combined into a single Prunus pathogen list, containing 102 pathogens (75 fungi, 18 viruses, 6 bacteria and 3 phytoplasm...

  19. Selected lipids activate phagosome actin assembly and maturation resulting in killing of pathogenic mycobacteria

    Microsoft Academic Search

    Elsa Anes; Mark Philipp Kühnel; Evelyne Bos; Jose Moniz-Pereira; Anja Habermann; Gareth Griffiths

    2003-01-01

    Pathogenic mycobacteria such as Mycobacterium tuberculosis and Mycobacterium avium facilitate disease by surviving intracellularly within a potentially hostile environment: the macrophage phagosome. They inhibit phagosome maturation processes, including fusion with lysosomes, acidification and, as shown here, membrane actin assembly. An in vitro assay developed for latex bead phagosomes (LBPs) provided insights into membrane signalling events that regulate phagosome actin assembly,

  20. Cell biology of Zymoseptoria tritici: Pathogen cell organization and wheat infection

    PubMed Central

    Steinberg, Gero

    2015-01-01

    Cell biological research in the wheat pathogen Zymoseptoria tritici (formerly Mycosphaerella graminicola) has led to a good understanding of the histology of the infection process. Expression profiling and bioinformatic approaches, combined with molecular studies on signaling pathways, effectors and potential necrosis factors provides first insight into the complex interplay between the host and the pathogen. Cell biological studies will help to further our understanding of the infection strategy of the fungus. The cellular organization and intracellular dynamics of the fungus itself is largely unexplored. Insight into essential cellular processes within the pathogen will expand our knowledge of the basic biology of Z. tritici, thereby providing putative new anti-fungal targets. PMID:26092785

  1. Inhibition of the PtdIns(5) kinase PIKfyve disrupts intracellular replication of Salmonella.

    PubMed

    Kerr, Markus C; Wang, Jack T H; Castro, Natalie A; Hamilton, Nicholas A; Town, Liam; Brown, Darren L; Meunier, Frederic A; Brown, Nat F; Stow, Jennifer L; Teasdale, Rohan D

    2010-04-21

    3-phosphorylated phosphoinositides (3-PtdIns) orchestrate endocytic trafficking pathways exploited by intracellular pathogens such as Salmonella to gain entry into the cell. To infect the host, Salmonellae subvert its normal macropinocytic activity, manipulating the process to generate an intracellular replicative niche. Disruption of the PtdIns(5) kinase, PIKfyve, be it by interfering mutant, siRNA-mediated knockdown or pharmacological means, inhibits the intracellular replication of Salmonella enterica serovar typhimurium in epithelial cells. Monitoring the dynamics of macropinocytosis by time-lapse 3D (4D) videomicroscopy revealed a new and essential role for PI(3,5)P(2) in macropinosome-late endosome/lysosome fusion, which is distinct from that of the small GTPase Rab7. This PI(3,5)P(2)-dependent step is required for the proper maturation of the Salmonella-containing vacuole (SCV) through the formation of Salmonella-induced filaments (SIFs) and for the engagement of the Salmonella pathogenicity island 2-encoded type 3 secretion system (SPI2-T3SS). Finally, although inhibition of PIKfyve in macrophages did inhibit Salmonella replication, it also appears to disrupt the macrophage's bactericidal response. PMID:20300065

  2. Evolution of microbial pathogens.

    PubMed Central

    Morschhäuser, J; Köhler, G; Ziebuhr, W; Blum-Oehler, G; Dobrindt, U; Hacker, J

    2000-01-01

    Various genetic mechanisms including point mutations, genetic rearrangements and lateral gene transfer processes contribute to the evolution of microbes. Long-term processes leading to the development of new species or subspecies are termed macroevolution, and short-term developments, which occur during days or weeks, are considered as microevolution. Both processes, macro- and microevolution need horizontal gene transfer, which is particularly important for the development of pathogenic microorganisms. Plasmids, bacteriophages and so-called pathogenicity islands (PAIs) play a crucial role in the evolution of pathogens. During microevolution, genome variability of pathogenic microbes leads to new phenotypes, which play an important role in the acute development of an infectious disease. Infections due to Staphylococcus epidermidis, Candida albicans and Escherichia coli will be described with special emphasis on processes of microevolution. In contrast, the development of PAIs is a process involved in macroevolution. PAIs are especially important in processes leading to new pathotypes or even species. In this review, particular attention will be given to the fact that the evolution of pathogenic microbes can be considered as a specific example for microbial evolution in general. PMID:10874741

  3. Identification of genes expressed by Phakopsora pachyrhizi, the pathogen causing soybean rust, at a late stage of infection of susceptible soybean leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soybean is one of the top five agricultural products in the United States and is highly susceptible to P. pachyrhizi, an exotic obligate biotrophic fungus. The amount of genomic information about P. pachyrhizi is small, which limits our understanding of the soybean-soybean rust pathogen interaction ...

  4. Neopolyploidy and pathogen resistance

    PubMed Central

    Oswald, Benjamin P; Nuismer, Scott L

    2007-01-01

    Despite the well-documented historical importance of polyploidy, the mechanisms responsible for the establishment and evolutionary success of novel polyploid lineages remain unresolved. One possibility, which has not been previously evaluated theoretically, is that novel polyploid lineages are initially more resistant to pathogens than the diploid progenitor species. Here, we explore this possibility by developing and analysing mathematical models of interactions between newly formed polyploid lineages and their pathogens. We find that for the genetic mechanisms of pathogen resistance with the best empirical support, newly formed polyploid populations of hosts are expected to be more resistant than their diploid progenitors. This effect can be quite strong and, in the case of perennial species with recurrent polyploid formation, may last indefinitely, potentially providing a general explanation for the successful establishment of novel polyploid lineages. PMID:17686733

  5. 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

  6. 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.

  7. Efficient intracellular delivery and improved biocompatibility of colloidal silver nanoparticles towards intracellular SERS immuno-sensing.

    PubMed

    Bhardwaj, Vinay; Srinivasan, Supriya; McGoron, Anthony J

    2015-06-21

    High throughput intracellular delivery strategies, electroporation, passive and TATHA2 facilitated diffusion of colloidal silver nanoparticles (AgNPs) are investigated for cellular toxicity and uptake using state-of-art analytical techniques. The TATHA2 facilitated approach efficiently delivered high payload with no toxicity, pre-requisites for intracellular applications of plasmonic metal nanoparticles (PMNPs) in sensing and therapeutics. PMID:25939798

  8. Esterified Trityl Radicals as Intracellular Oxygen Probes

    PubMed Central

    Liu, Yangping; Villamena, Frederick A.; Sun, Jian; Wang, Tse-yao

    2009-01-01

    Triarylmethyl (trityl) radicals exhibit high stability and narrow line width at physiological conditions which provide high sensitivity and resolution for the measurement of O2 concentration, making them attractive as EPR oximetry probes. However, the application of previously available compounds has been limited by their poor intracellular permeability. We recently reported the synthesis and characterization of esterified trityl radicals as potential intracellular EPR probes and their oxygen sensitivity, redox properties and enzyme-mediated hydrolysis were investigated. In this paper, we report the cellular permeability and stability of these trityls in the presence of bovine aortic endothelial cells. Results show that the acetoxymethoxycarbonyl-containing trityl AMT-02 exhibits high stability in the presence of cells and can be effectively internalized. The intracellular hydrolysis of AMT-02 to the carboxylate form of the trityl (CT-03) was also observed. In addition, this internalized trityl probe was applied to measure intracellular O2 concentrations and the effects of menadione and KCN on the rates of O2 consumption in endothelial cells. This study demonstrates that these esterified trityl radicals can function as effective EPR oximetry probes measuring intracellular O2 concentration and consumption. PMID:19135524

  9. Ferrochelatase Is Present in Brucella abortus and Is Critical for Its Intracellular Survival and Virulence

    PubMed Central

    Almirón, Marta; Martínez, Marcela; Sanjuan, Norberto; Ugalde, Rodolfo A.

    2001-01-01

    Brucella spp. are pathogenic bacteria that cause brucellosis, an animal disease which can also affect humans. Although understanding the pathogenesis is important for the health of animals and humans, little is known about virulence factors associated with it. In order for chronic disease to be established, Brucella spp. have developed the ability to survive inside phagocytes by evading cell defenses. It hides inside vacuoles, where it then replicates, indicating that it has an active metabolism. The purpose of this work was to obtain better insight into the intracellular metabolism of Brucella abortus. During a B. abortus genomic sequencing project, a clone coding a putative gene homologous to hemH was identified and sequenced. The amino acid sequence revealed high homology to members of the ferrochelatase family. A knockout mutant displayed auxotrophy for hemin, defective intracellular survival inside J774 and HeLa cells, and lack of virulence in BALB/c mice. This phenotype was overcome by complementing the mutant strain with a plasmid harboring wild-type hemH. These data demonstrate that B. abortus synthesizes its own heme and also has the ability to use an external source of heme; however, inside cells, there is not enough available heme to support its intracellular metabolism. It is concluded that ferrochelatase is essential for the multiplication and intracellular survival of B. abortus and thus for the establishment of chronic disease as well. PMID:11553564

  10. Noncanonical inflammasome activation of caspase-4/caspase-11 mediates epithelial defenses against enteric bacterial pathogens.

    PubMed

    Knodler, Leigh A; Crowley, Shauna M; Sham, Ho Pan; Yang, Hyungjun; Wrande, Marie; Ma, Caixia; Ernst, Robert K; Steele-Mortimer, Olivia; Celli, Jean; Vallance, Bruce A

    2014-08-13

    Inflammasome-mediated host defenses have been extensively studied in innate immune cells. Whether inflammasomes function for innate defense in intestinal epithelial cells, which represent the first line of defense against enteric pathogens, remains unknown. We observed enhanced Salmonella enterica serovar Typhimurium colonization in the intestinal epithelium of caspase-11-deficient mice, but not at systemic sites. In polarized epithelial monolayers, siRNA-mediated depletion of caspase-4, a human ortholog of caspase-11, also led to increased bacterial colonization. Decreased rates of pyroptotic cell death, a host defense mechanism that extrudes S. Typhimurium-infected cells from the polarized epithelium, accounted for increased pathogen burdens. The caspase-4 inflammasome also governs activation of the proinflammatory cytokine, interleukin (IL)-18, in response to intracellular (S. Typhimurium) and extracellular (enteropathogenic Escherichia coli) enteric pathogens, via intracellular LPS sensing. Therefore, an epithelial cell-intrinsic noncanonical inflammasome plays a critical role in antimicrobial defense at the intestinal mucosal surface. PMID:25121752

  11. The Role of Cysteine Proteinases and their Inhibitors in the Host-Pathogen Cross Talk

    PubMed Central

    Kopitar-Jerala, Nataša

    2012-01-01

    Proteinases and their inhibitors play essential functional roles in basic biological processes in both hosts and pathogens. Endo/lysosomal cathepsins participate in immune response in pathogen recognition and elimination. They are essential for both antigen processing and presentation (host adaptive immune response) and activation of endosomal Toll like receptors (innate immune response). Pathogens can produce proteases and also natural inhibitors to subvert the host immune response. Several pathogens are sensed through the intracellular pathogen recognition receptors, but only some of them use the host proteolytic system to escape into the cytosol. In this review, I provide an update on the most recent developments regarding the role of proteinases and their inhibitors in the initiation and regulation of immune responses. PMID:23305363

  12. Host-to-Pathogen Gene Transfer Facilitated Infection of Insects by a Pathogenic Fungus

    PubMed Central

    Zhao, Hong; Xu, Chuan; Lu, Hsiao-Ling; Chen, Xiaoxuan; St. Leger, Raymond J.; Fang, Weiguo

    2014-01-01

    Metarhizium robertsii is a plant root colonizing fungus that is also an insect pathogen. Its entomopathogenicity is a characteristic that was acquired during evolution from a plant endophyte ancestor. This transition provides a novel perspective on how new functional mechanisms important for host switching and virulence have evolved. From a random T-DNA insertion library, we obtained a pathogenicity defective mutant that resulted from the disruption of a sterol carrier gene (Mr-npc2a). Phylogenetic analysis revealed that Metarhizium acquired Mr-npc2a from an insect by horizontal gene transfer (HGT). Mr-NPC2a binds to cholesterol, an animal sterol, rather than the fungal sterol ergosterol, indicating it retains the specificity of insect NPC2 proteins. Mr-NPC2a is an intracellular protein and is exclusively expressed in the hemolymph of living insects. The disruption of Mr-npc2a reduced the amount of sterol in cell membranes of the yeast-like hyphal bodies that facilitate dispersal in the host body. These were consequently more susceptible to insect immune responses than the wild type. Transgenic expression of Mr-NPC2a increased the virulence of Beauveria bassiana, an endophytic insect-pathogenic fungus that lacks a Mr-NPC2a homolog. PMID:24722668

  13. Chemical development of intracellular protein heterodimerizers.

    PubMed

    Erhart, Dominik; Zimmermann, Mirjam; Jacques, Olivier; Wittwer, Matthias B; Ernst, Beat; Constable, Edwin; Zvelebil, Marketa; Beaufils, Florent; Wymann, Matthias P

    2013-04-18

    Cell activation initiated by receptor ligands or oncogenes triggers complex and convoluted intracellular signaling. Techniques initiating signals at defined starting points and cellular locations are attractive to elucidate the output of selected pathways. Here, we present the development and validation of a protein heterodimerization system based on small molecules cross-linking fusion proteins derived from HaloTags and SNAP-tags. Chemical dimerizers of HaloTag and SNAP-tag (HaXS) show excellent selectivity and have been optimized for intracellular reactivity. HaXS force protein-protein interactions and can translocate proteins to various cellular compartments. Due to the covalent nature of the HaloTag-HaXS-SNAP-tag complex, intracellular dimerization can be easily monitored. First applications include protein targeting to cytoskeleton, to the plasma membrane, to lysosomes, the initiation of the PI3K/mTOR pathway, and multiplexed protein complex formation in combination with the rapamycin dimerization system. PMID:23601644

  14. Bacterial Community Morphogenesis Is Intimately Linked to the Intracellular Redox State

    PubMed Central

    Okegbe, Chinweike; Price-Whelan, Alexa; Sakhtah, Hassan; Hunter, Ryan C.; Newman, Dianne K.

    2013-01-01

    Many microbial species form multicellular structures comprising elaborate wrinkles and concentric rings, yet the rules governing their architecture are poorly understood. The opportunistic pathogen Pseudomonas aeruginosa produces phenazines, small molecules that act as alternate electron acceptors to oxygen and nitrate to oxidize the intracellular redox state and that influence biofilm morphogenesis. Here, we show that the depth occupied by cells within colony biofilms correlates well with electron acceptor availability. Perturbations in the environmental provision, endogenous production, and utilization of electron acceptors affect colony development in a manner consistent with redox control. Intracellular NADH levels peak before the induction of colony wrinkling. These results suggest that redox imbalance is a major factor driving the morphogenesis of P. aeruginosa biofilms and that wrinkling itself is an adaptation that maximizes oxygen accessibility and thereby supports metabolic homeostasis. This type of redox-driven morphological change is reminiscent of developmental processes that occur in metazoans. PMID:23292774

  15. 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...

  16. 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...

  17. Actinomycetes as plant pathogens

    Microsoft Academic Search

    Romano Locci

    1994-01-01

    Biology, taxonomy, pathogenicity and control of plant disease inducing actinomycetes are reviewed. Recent progress in the study of potato, sweet potato, blueberry and fruit and forest tree diseases is illustrated. The role in potato scab pathogenesis of the newly discovered phytotoxins, thaxtomins, is discussed.

  18. 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

  19. 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...

  20. Intracellular phenotype of Mycobacterium avium enters macrophages primarily by a macropinocytosis-like mechanism and survives in a compartment that differs from that with extracellular phenotype

    Microsoft Academic Search

    Luiz E. Bermudez; Mary Petrofsky; Felix Sangari

    2004-01-01

    Mycobacterium avium uptake by human macrophages differs between the phenotypes of bacterium grown in laboratory media (extracellular growth, EG) and bacterium grown within macrophages (intracellular growth, IG). Studies in vivo have confirmed that, when spreading, pathogenic mycobacteria enter macrophages by a complement receptor 3-independent pathway, in contrast to mycobacteria uptake in vitro. M. avium, grown in macrophages (IG) for 3