Sample records for obligate intracellular bacterial

  1. Advances in genetic manipulation of obligate intracellular bacterial pathogens.

    PubMed

    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. Proteomic Profiling of the Outer Membrane Fraction of the Obligate Intracellular Bacterial Pathogen Ehrlichia ruminantium

    PubMed Central

    Moumène, Amal; Marcelino, Isabel; Ventosa, Miguel; Gros, Olivier; Lefrançois, Thierry; Vachiéry, Nathalie

    2015-01-01

    The outer membrane proteins (OMPs) of Gram-negative bacteria play a crucial role in virulence and pathogenesis. Identification of these proteins represents an important goal for bacterial proteomics, because it aids in vaccine development. Here, we have developed such an approach for Ehrlichia ruminantium, the obligate intracellular bacterium that causes heartwater. A preliminary whole proteome analysis of elementary bodies, the extracellular infectious form of the bacterium, had been performed previously, but information is limited about OMPs in this organism and about their role in the protective immune response. Identification of OMPs is also essential for understanding Ehrlichia’s OM architecture, and how the bacterium interacts with the host cell environment. First, we developed an OMP extraction method using the ionic detergent sarkosyl, which enriched the OM fraction. Second, proteins were separated via one-dimensional electrophoresis, and digested peptides were analyzed via nano-liquid chromatographic separation coupled with mass spectrometry (LC-MALDI-TOF/TOF). Of 46 unique proteins identified in the OM fraction, 18 (39%) were OMPs, including 8 proteins involved in cell structure and biogenesis, 4 in transport/virulence, 1 porin, and 5 proteins of unknown function. These experimental data were compared to the predicted subcellular localization of the entire E. ruminantium proteome, using three different algorithms. This work represents the most complete proteome characterization of the OM fraction in Ehrlichia spp. The study indicates that suitable subcellular fractionation experiments combined with straightforward computational analysis approaches are powerful for determining the predominant subcellular localization of the experimentally observed proteins. We identified proteins potentially involved in E. ruminantium pathogenesis, which are good novel targets for candidate vaccines. Thus, combining bioinformatics and proteomics, we discovered new OMPs for E. ruminantium that are valuable data for those investigating new vaccines against this organism. In summary, we provide both pioneering data and novel insights into the pathogenesis of this obligate intracellular bacterium. PMID:25710494

  3. Proteomic Profiling of the Outer Membrane Fraction of the Obligate Intracellular Bacterial Pathogen Ehrlichia ruminantium.

    PubMed

    Moumène, Amal; Marcelino, Isabel; Ventosa, Miguel; Gros, Olivier; Lefrançois, Thierry; Vachiéry, Nathalie; Meyer, Damien F; Coelho, Ana V

    2015-01-01

    The outer membrane proteins (OMPs) of Gram-negative bacteria play a crucial role in virulence and pathogenesis. Identification of these proteins represents an important goal for bacterial proteomics, because it aids in vaccine development. Here, we have developed such an approach for Ehrlichia ruminantium, the obligate intracellular bacterium that causes heartwater. A preliminary whole proteome analysis of elementary bodies, the extracellular infectious form of the bacterium, had been performed previously, but information is limited about OMPs in this organism and about their role in the protective immune response. Identification of OMPs is also essential for understanding Ehrlichia's OM architecture, and how the bacterium interacts with the host cell environment. First, we developed an OMP extraction method using the ionic detergent sarkosyl, which enriched the OM fraction. Second, proteins were separated via one-dimensional electrophoresis, and digested peptides were analyzed via nano-liquid chromatographic separation coupled with mass spectrometry (LC-MALDI-TOF/TOF). Of 46 unique proteins identified in the OM fraction, 18 (39%) were OMPs, including 8 proteins involved in cell structure and biogenesis, 4 in transport/virulence, 1 porin, and 5 proteins of unknown function. These experimental data were compared to the predicted subcellular localization of the entire E. ruminantium proteome, using three different algorithms. This work represents the most complete proteome characterization of the OM fraction in Ehrlichia spp. The study indicates that suitable subcellular fractionation experiments combined with straightforward computational analysis approaches are powerful for determining the predominant subcellular localization of the experimentally observed proteins. We identified proteins potentially involved in E. ruminantium pathogenesis, which are good novel targets for candidate vaccines. Thus, combining bioinformatics and proteomics, we discovered new OMPs for E. ruminantium that are valuable data for those investigating new vaccines against this organism. In summary, we provide both pioneering data and novel insights into the pathogenesis of this obligate intracellular bacterium. PMID:25710494

  4. Genetic Systems for Studying Obligate Intracellular Pathogens: An Update

    PubMed Central

    Wood, David O.; Wood, Raphael R.; Tucker, Aimee M.

    2013-01-01

    Rapid advancements in the genetic manipulation of obligate intracellular bacterial pathogens have been made over the past two years. In this paper we attempt to summarize the work published since 2011 that documents these exciting accomplishments. While each genus comprising this diverse group of pathogens poses unique problems, requiring modifications of established techniques and the introduction of new tools, all appear amenable to genetic analysis. Significantly, the field is moving forward from a focus on the identification and development of genetic techniques to their application in addressing critical questions related to mechanisms of bacterial pathogenicity and the requirements of obligate intracellular growth. PMID:24581687

  5. Secretome of obligate intracellular Rickettsia.

    PubMed

    Gillespie, Joseph J; Kaur, Simran J; Rahman, M Sayeedur; Rennoll-Bankert, Kristen; Sears, Khandra T; Beier-Sexton, Magda; Azad, Abdu F

    2014-08-28

    The genus Rickettsia (Alphaproteobacteria, Rickettsiales, Rickettsiaceae) is comprised of obligate intracellular parasites, with virulent species of interest both as causes of emerging infectious diseases and for their potential deployment as bioterrorism agents. Currently, there are no effective commercially available vaccines, with treatment limited primarily to tetracycline antibiotics, although others (e.g. josamycin, ciprofloxacin, chloramphenicol, and azithromycin) are also effective. Much of the recent research geared toward understanding mechanisms underlying rickettsial pathogenicity has centered on characterization of secreted proteins that directly engage eukaryotic cells. Herein, we review all aspects of the Rickettsia secretome, including six secretion systems, 19 characterized secretory proteins, and potential moonlighting proteins identified on surfaces of multiple Rickettsia species. Employing bioinformatics and phylogenomics, we present novel structural and functional insight on each secretion system. Unexpectedly, our investigation revealed that the majority of characterized secretory proteins have not been assigned to their cognate secretion pathways. Furthermore, for most secretion pathways, the requisite signal sequences mediating translocation are poorly understood. As a blueprint for all known routes of protein translocation into host cells, this resource will assist research aimed at uniting characterized secreted proteins with their apposite secretion pathways. Furthermore, our work will help in the identification of novel secreted proteins involved in rickettsial 'life on the inside'. PMID:25168200

  6. Microsporidian genome analysis reveals evolutionary strategies for obligate intracellular growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microsporidia comprise a large phylum of obligate intracellular eukaryotes that are fungalrelated parasites responsible for widespread disease, and here we address questions about microsporidia biology and evolution. We sequenced three microsporidian genomes from two species, Nematocida parisii and...

  7. 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

  8. 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

  9. Lateral Phage Transfer in Obligate Intracellular Bacteria (Wolbachia): Verification from Natural Populations

    PubMed Central

    Chafee, Meghan E.; Funk, Daniel J.; Harrison, Richard G.; Bordenstein, Seth R.

    2010-01-01

    Lateral transfer of mobile DNA is a hallmark of bacteria with a free-living replicative stage; however, its significance in obligate intracellular bacteria and other heritable endosymbionts remains controversial. Comparative sequence analyses from laboratory stocks infected with Wolbachia pipientis provide some of the most compelling evidence that bacteriophage WO-B transfers laterally between infections of the same insect host. Lateral transfer between coinfections, however, has been evaluated neither in natural populations nor between closely related Wolbachia strains. Here, we analyze bacterial and phage genes from two pairs of natural sympatric field isolates, of Gryllus pennsylvanicus field crickets and of Neochlamisus bebbianae leaf beetles, to demonstrate WO-B transfers between supergroup B Wolbachia. N. bebbianae revealed the highest number of phage haplotypes yet recorded, hinting that lab lines could underestimate phage haplotype variation and lateral transfer. Finally, using the approximate age of insect host species as the maximum available time for phage transfer between host-associated bacteria, we very conservatively estimate phage WO-B transfer to occur at least once every 0–5.4 My within a host species. Increasing discoveries of mobile elements, intragenic recombination, and bacterial coinfections in host-switching obligate intracellular bacteria specify that mobile element transfer is common in these species. PMID:19906794

  10. Microsporidian genome analysis reveals evolutionary strategies for obligate intracellular growth.

    PubMed

    Cuomo, Christina A; Desjardins, Christopher A; Bakowski, Malina A; Goldberg, Jonathan; Ma, Amy T; Becnel, James J; Didier, Elizabeth S; Fan, Lin; Heiman, David I; Levin, Joshua Z; Young, Sarah; Zeng, Qiandong; Troemel, Emily R

    2012-12-01

    Microsporidia comprise a large phylum of obligate intracellular eukaryotes that are fungal-related parasites responsible for widespread disease, and here we address questions about microsporidia biology and evolution. We sequenced three microsporidian genomes from two species, Nematocida parisii and Nematocida sp1, which are natural pathogens of Caenorhabditis nematodes and provide model systems for studying microsporidian pathogenesis. We performed deep sequencing of transcripts from a time course of N. parisii infection. Examination of pathogen gene expression revealed compact transcripts and a dramatic takeover of host cells by Nematocida. We also performed phylogenomic analyses of Nematocida and other microsporidian genomes to refine microsporidian phylogeny and identify evolutionary events of gene loss, acquisition, and modification. In particular, we found that all microsporidia lost the tumor-suppressor gene retinoblastoma, which we speculate could accelerate the parasite cell cycle and increase the mutation rate. We also found that microsporidia acquired transporters that could import nucleosides to fuel rapid growth. In addition, microsporidian hexokinases gained secretion signal sequences, and in a functional assay these were sufficient to export proteins out of the cell; thus hexokinase may be targeted into the host cell to reprogram it toward biosynthesis. Similar molecular changes appear during formation of cancer cells and may be evolutionary strategies adopted independently by microsporidia to proliferate rapidly within host cells. Finally, analysis of genome polymorphisms revealed evidence for a sexual cycle that may provide genetic diversity to alleviate problems caused by clonal growth. Together these events may explain the emergence and success of these diverse intracellular parasites. PMID:22813931

  11. Microsporidian genome analysis reveals evolutionary strategies for obligate intracellular growth

    PubMed Central

    Cuomo, Christina A.; Desjardins, Christopher A.; Bakowski, Malina A.; Goldberg, Jonathan; Ma, Amy T.; Becnel, James J.; Didier, Elizabeth S.; Fan, Lin; Heiman, David I.; Levin, Joshua Z.; Young, Sarah; Zeng, Qiandong; Troemel, Emily R.

    2012-01-01

    Microsporidia comprise a large phylum of obligate intracellular eukaryotes that are fungal-related parasites responsible for widespread disease, and here we address questions about microsporidia biology and evolution. We sequenced three microsporidian genomes from two species, Nematocida parisii and Nematocida sp1, which are natural pathogens of Caenorhabditis nematodes and provide model systems for studying microsporidian pathogenesis. We performed deep sequencing of transcripts from a time course of N. parisii infection. Examination of pathogen gene expression revealed compact transcripts and a dramatic takeover of host cells by Nematocida. We also performed phylogenomic analyses of Nematocida and other microsporidian genomes to refine microsporidian phylogeny and identify evolutionary events of gene loss, acquisition, and modification. In particular, we found that all microsporidia lost the tumor-suppressor gene retinoblastoma, which we speculate could accelerate the parasite cell cycle and increase the mutation rate. We also found that microsporidia acquired transporters that could import nucleosides to fuel rapid growth. In addition, microsporidian hexokinases gained secretion signal sequences, and in a functional assay these were sufficient to export proteins out of the cell; thus hexokinase may be targeted into the host cell to reprogram it toward biosynthesis. Similar molecular changes appear during formation of cancer cells and may be evolutionary strategies adopted independently by microsporidia to proliferate rapidly within host cells. Finally, analysis of genome polymorphisms revealed evidence for a sexual cycle that may provide genetic diversity to alleviate problems caused by clonal growth. Together these events may explain the emergence and success of these diverse intracellular parasites. PMID:22813931

  12. Disrupting Protein Expression with Peptide Nucleic Acids Reduces Infection by Obligate Intracellular Rickettsia

    PubMed Central

    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

  13. 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

  14. Ileal Symbiont Intracellularis, an Obligate Intracellular Bacterium of Porcine Intestines Showing a Relationship to Desulfovibrio Species

    Microsoft Academic Search

    CONNIE J. GEBHART; SUSAN M. BARNS; GAO-FENG LIN

    A new genus and species of obligate intracellular bacteria found in porcine intestines are described. Growth on any bacteriological medium deprived of living cells has not been demonstrated. The organism has been grown intracellularly in cell culture. The 16s rRNA gene sequence data, DNA probe results, and microscopic observations provide evidence that these bacteria differ from those in other described

  15. 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

  16. Bacterial Pathogens Commandeer Rab GTPases to Establish Intracellular Niches

    PubMed Central

    Stein, Mary-Pat; Müller, Matthias P.; Wandinger-Ness, Angela

    2012-01-01

    Intracellular bacterial pathogens deploy virulence factors termed effectors to inhibit degradation by host cells and to establish intracellular niches where growth and differentiation take place. Here, we describe mechanisms by which human bacterial pathogens (including Chlamydiae; Coxiella burnetii; Helicobacter pylori; Legionella pneumophila; Listeria monocytogenes; Mycobacteria; Pseudomonas aeruginosa, Salmonella enterica) modulate endocytic and exocytic Rab GTPases in order to thrive in host cells. Host cell Rab GTPases are critical for intracellular transport following pathogen phagocytosis or endocytosis. At the molecular level bacterial effectors hijack Rab protein function to: evade degradation, direct transport to particular intracellular locations, and monopolize host vesicles carrying molecules that are needed for a stable niche and/or bacterial growth and differentiation. Bacterial effectors may serve as specific receptors for Rab GTPases or as enzymes that post-translationally modify Rab proteins or endosomal membrane lipids required for Rab function. Emerging data indicate that bacterial effector expression is temporally and spatially regulated and multiple virulence factors may act concertedly to usurp Rab GTPase function, alter signaling and ensure niche establishment and intracellular bacterial growth, making this field an exciting area for further study. PMID:22901006

  17. 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

  18. Intracellular activity of azithromycin against bacterial enteric pathogens.

    PubMed Central

    Rakita, R M; Jacques-Palaz, K; Murray, B E

    1994-01-01

    Azithromycin, a new azalide antibiotic, is active in vitro against a variety of enteric bacterial pathogens. Since it is concentrated inside human neutrophils and other cells, it might be particularly useful in the treatment of infections caused by enteropathogens that invade host tissues. The intracellular activity of azithromycin against several enteric pathogens that had been phagocytosed by neutrophils was determined. Azithromycin was effective in reducing the intracellular viabilities of almost all strains tested, including representative strains of Salmonella, Shigella, and enteroinvasive, enteropathogenic, enterotoxigenic, and enterohemorrhagic Escherichia coli. Erythromycin was also effective in this model system, although azithromycin was generally more effective than erythromycin against strains of invasive enteric pathogens. Cefotaxime reduced intracellular bacterial viability to a lesser extent than either azithromycin or erythromycin. The presence of neutrophils did not significantly affect the activity of azithromycin in this system. Azithromycin may be a useful agent for the treatment of bacterial diarrhea, and clinical trials should be considered. PMID:7810998

  19. Autophagic clearance of bacterial pathogens: molecular recognition of intracellular microorganisms

    PubMed Central

    Mansilla Pareja, Maria Eugenia; Colombo, Maria I.

    2013-01-01

    Autophagy is involved in several physiological and pathological processes. One of the key roles of the autophagic pathway is to participate in the first line of defense against the invasion of pathogens, as part of the innate immune response. Targeting of intracellular bacteria by the autophagic machinery, either in the cytoplasm or within vacuolar compartments, helps to control bacterial proliferation in the host cell, controlling also the spreading of the infection. In this review we will describe the means used by diverse bacterial pathogens to survive intracellularly and how they are recognized by the autophagic molecular machinery, as well as the mechanisms used to avoid autophagic clearance. PMID:24137567

  20. Intracellular Bacterial Biofilm-Like Pods in Urinary Tract Infections

    Microsoft Academic Search

    Gregory G. Anderson; Joseph J. Palermo; Joel D. Schilling; Robyn Roth; John Heuser; Scott J. Hultgren

    2003-01-01

    Escherichia coli entry into the bladder is met with potent innate defenses, including neutrophil influx and epithelial exfoliation. Bacterial subversion of innate responses involves invasion into bladder superficial cells. We discovered that the intracellular bacteria matured into biofilms, creating pod-like bulges on the bladder surface. Pods contained bacteria encased in a polysaccharide-rich matrix surrounded by a protective shell of uroplakin.

  1. Survival Strategy of Obligately Intracellular Ehrlichia chaffeensis: Novel Modulation of Immune Response and Host Cell Cycles

    PubMed Central

    Zhang, Jian-zhi; Sinha, Mala; Luxon, Bruce A.; Yu, Xue-jie

    2004-01-01

    Ehrlichia chaffeensis is an obligatory intracellular bacterium which resides in an early endosome in monocytes. E. chaffeensis infection in a human monocyte cell line (THP1) significantly altered the transcriptional levels of 4.5% of host genes, including those coding for apoptosis inhibitors, proteins regulating cell differentiation, signal transduction, proinflammatory cytokines, biosynthetic and metabolic proteins, and membrane trafficking proteins. The transcriptional profile of the host cell revealed key themes in the pathogenesis of Ehrlichia. First, E. chaffeensis avoided stimulation of or repressed the transcription of cytokines involved in the early innate immune response and cell-mediated immune response to intracellular microbes, such as the interleukin-12 (IL-12), IL-15, and IL-18 genes, which might make Ehrlichia a stealth organism for the macrophage. Second, E. chaffeensis up-regulated NF-?B and apoptosis inhibitors and differentially regulated cell cyclins and CDK expression, which may enhance host cell survival. Third, E. chaffeensis also inhibited the gene transcription of RAB5A, SNAP23, and STX16, which are involved in membrane trafficking. By comparing the transcriptional response of macrophages infected with other bacteria and that of macrophages infected with E. chaffeensis, we have identified few genes that are commonly induced and no commonly repressed genes. These results illustrate the stereotyped macrophage response to other pathogens, in contrast with the novel host response to obligate intracellular Ehrlichia, whose survival depends entirely on a long evolutionary process of outmaneuvering macrophages. PMID:14688131

  2. Biological Properties and Cell Tropism of Chp2, a Bacteriophage of the Obligate Intracellular Bacterium Chlamydophila abortus

    Microsoft Academic Search

    J. S. Everson; S. A. Garner; B. Fane; B.-L. Liu; P. R. Lambden; I. N. Clarke

    2002-01-01

    A number of bacteriophages belonging to the Microviridae have been described infecting chlamydiae. Phy- logenetic studies divide the Chlamydiaceae into two distinct genera, Chlamydia and Chlamydophila, containing three and six different species, respectively. In this work we investigated the biological properties and host range of the recently described bacteriophage Chp2 that was originally discovered in Chlamydophila abortus. The obligate intracellular

  3. The Obligate Intracellular Parasite Toxoplasma gondii Secretes a Soluble Phosphatidylserine Decarboxylase*

    PubMed Central

    Gupta, Nishith; Hartmann, Anne; Lucius, Richard; Voelker, Dennis R.

    2012-01-01

    Toxoplasma gondii is an obligate intracellular parasite capable of causing fatal infections in immunocompromised individuals and neonates. Examination of the phosphatidylserine (PtdSer) metabolism of T. gondii reveals that the parasite secretes a soluble form of PtdSer decarboxylase (TgPSD1), which preferentially decarboxylates liposomal PtdSer with an apparent Km of 67 ?m. The specific enzyme activity increases by 3-fold during the replication of T. gondii, and soluble phosphatidylserine decarboxylase (PSD) accounts for ?20% of the total PSD, prior to the parasite egress from the host cells. Extracellular T. gondii secreted ?20% of its total PSD activity at 37 °C, and the intracellular Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N?,N?-tetraacetic acid tetrakis (acetoxymethyl ester) inhibited the process by 50%. Cycloheximide, brefeldin A, ionic composition of the medium, and exogenous PtdSer did not modulate the enzyme secretion, which suggests a constitutive discharge of a presynthesized pool of PSD in axenic T. gondii. TgPSD1 consists of 968 amino acids with a 26-amino acid hydrophobic peptide at the N terminus and no predicted membrane domains. Parasites overexpressing TgPSD1-HA secreted 10-fold more activity compared with the parental strain. Exposure of apoptotic Jurkat cells to transgenic parasites demonstrated interfacial catalysis by secreted TgPSD1 that reduced host cell surface exposure of PtdSer. Immunolocalization experiments revealed that TgPSD1 resides in the dense granules of T. gondii and is also found in the parasitophorous vacuole of replicating parasites. Together, these findings demonstrate novel features of the parasite enzyme because a secreted, soluble, and interfacially active form of PSD has not been previously described for any organism. PMID:22563079

  4. Pathogenic Potential of Novel Chlamydiae and Diagnostic Approaches to Infections Due to These Obligate Intracellular Bacteria

    PubMed Central

    Corsaro, Daniele; Greub, Gilbert

    2006-01-01

    Novel chlamydiae are newly recognized members of the phylum Chlamydiales that are only distantly related to the classic Chlamydiaceae, i.e., Chlamydia and Chlamydophila species. They also exibit an obligate biphasic intracellular life cycle within eukaryote host cells. Some of these new chlamydiae are currently considered potential emerging human and/or animal pathogens. Parachlamydia acanthamoebae and Simkania negevensis are both emerging respiratory human pathogens, Waddlia chondrophila could be a novel abortigenic bovine agent, and Piscichlamydia salmonis has recently been identified as an agent of the gill epitheliocystis in the Atlantic salmon. Fritschea spp. and Rhabdochlamydia spp. seem to be confined to arthropods, but some evidence for human exposure exists. In this review, we first summarize the data supporting a pathogenic potential of the novel chlamydiae for humans and other vertebrates and the interactions that most of these chlamydiae have with free-living amoebae. We then review the diagnostic approaches to infections potentially due to the novel chlamydiae, especially focusing on the currently available PCR-based protocols, mammalian cell culture, the amoebal coculture system, and serology. PMID:16614250

  5. The genome of obligately intracellular Ehrlichia canis revealsthemes of complex membrane structure and immune evasion strategies

    SciTech Connect

    Mavromatis, K.; Kuyler Doyle, C.; Lykidis, A.; Ivanova, N.; Francino, P.; Chain, P.; Shin, M.; Malfatti, S.; Larimer, F.; Copeland,A.; Detter, J.C.; Land, M.; Richardson, P.M.; Yu, X.J.; Walker, D.H.; McBride, J.W.; Kyrpides, N.C.

    2005-09-01

    Ehrlichia canis, a small obligately intracellular, tick-transmitted, gram-negative, a-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, and 17 putative pseudogenes, and a substantial proportion of non-coding sequence (27 percent). 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. Proteins associated with pathogen-host interactions were identified including a small group of proteins (12) with tandem repeats and another with eukaryotic-like ankyrin domains (7).

  6. 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

  7. 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

  8. Bacterial Community Morphogenesis Is Intimately Linked to the Intracellular Redox State

    E-print Network

    Dietrich, Lars

    Bacterial Community Morphogenesis Is Intimately Linked to the Intracellular Redox State Lars E. P to oxidize the intracellular redox state and that influence biofilm morphogenesis. Here, we show driving the morphogenesis of P. aeruginosa bio- films and that wrinkling itself is an adaptation

  9. A Novel Obligate Intracellular Gamma-Proteobacterium Associated with Ixodid Ticks, Diplorickettsia massiliensis, Gen. Nov., Sp. Nov

    PubMed Central

    Mediannikov, Oleg; Sekeyová, Zuzana; Birg, Marie-Laure; Raoult, Didier

    2010-01-01

    Background Obligate intracellular bacteria of arthropods often exhibit a significant role in either human health or arthropod ecology. Methodology/Principal Findings An obligate intracellular gamma-proteobacterium was isolated from the actively questing hard tick Ixodes ricinus using mammalian and amphibian cell lines. Transmission electron microscopy revealed a unique morphology of the bacterium, including intravacuolar localization of bacteria grouped predominantly in pairs and internal structures composed of electron-dense crystal-like structures and regular multilayer sheath-like structures. The isolate 20B was characterized to determine its taxonomic position using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that this strain belongs to the family Coxiellaceae, order Legionellales of Gamma-proteobacteria, and the closest relatives are different Rickettsiella spp. The level of 16S rRNA gene sequence similarity between strain 20B and other recognized species of the family was below 94.5%. Partial sequences of the rpoB, parC and ftsY genes confirmed the phylogenetic position of the new isolate. The G+C content estimated on the basis of whole genome analysis of strain 20B was 37.88%. On the basis of its phenotypic and genotypic properties, together with phylogenetic distinctiveness, we propose that strain 20B to be classified in the new genus Diplorickettsia as the type strain of a novel species named Diplorickettsia massiliensis sp. nov. Conclusions/Significance Considering the source of its isolation (hard tick, often biting humans) the role of this bacterium in the pathology of humans, animals and ticks should be further investigated. PMID:20644718

  10. Infection of zebrafish embryos with intracellular bacterial pathogens.

    PubMed

    Benard, Erica L; van der Sar, Astrid M; Ellett, Felix; Lieschke, Graham J; Spaink, Herman P; Meijer, Annemarie H

    2012-01-01

    Zebrafish (Danio rerio) embryos are increasingly used as a model for studying the function of the vertebrate innate immune system in host-pathogen interactions. The major cell types of the innate immune system, macrophages and neutrophils, develop during the first days of embryogenesis prior to the maturation of lymphocytes that are required for adaptive immune responses. The ease of obtaining large numbers of embryos, their accessibility due to external development, the optical transparency of embryonic and larval stages, a wide range of genetic tools, extensive mutant resources and collections of transgenic reporter lines, all add to the versatility of the zebrafish model. Salmonella enterica serovar Typhimurium (S. typhimurium) and Mycobacterium marinum can reside intracellularly in macrophages and are frequently used to study host-pathogen interactions in zebrafish embryos. The infection processes of these two bacterial pathogens are interesting to compare because S. typhimurium infection is acute and lethal within one day, whereas M. marinum infection is chronic and can be imaged up to the larval stage. The site of micro-injection of bacteria into the embryo determines whether the infection will rapidly become systemic or will initially remain localized. A rapid systemic infection can be established by micro-injecting bacteria directly into the blood circulation via the caudal vein at the posterior blood island or via the Duct of Cuvier, a wide circulation channel on the yolk sac connecting the heart to the trunk vasculature. At 1 dpf, when embryos at this stage have phagocytically active macrophages but neutrophils have not yet matured, injecting into the blood island is preferred. For injections at 2-3 dpf, when embryos also have developed functional (myeloperoxidase-producing) neutrophils, the Duct of Cuvier is preferred as the injection site. To study directed migration of myeloid cells towards local infections, bacteria can be injected into the tail muscle, otic vesicle, or hindbrain ventricle. In addition, the notochord, a structure that appears to be normally inaccessible to myeloid cells, is highly susceptible to local infection. A useful alternative for high-throughput applications is the injection of bacteria into the yolk of embryos within the first hours after fertilization. Combining fluorescent bacteria and transgenic zebrafish lines with fluorescent macrophages or neutrophils creates ideal circumstances for multi-color imaging of host-pathogen interactions. This video article will describe detailed protocols for intravenous and local infection of zebrafish embryos with S. typhimurium or M. marinum bacteria and for subsequent fluorescence imaging of the interaction with cells of the innate immune system. PMID:22453760

  11. Infection of Zebrafish Embryos with Intracellular Bacterial Pathogens

    PubMed Central

    Benard, Erica L.; van der Sar, Astrid M.; Ellett, Felix; Lieschke, Graham J.; Spaink, Herman P.; Meijer, Annemarie H.

    2012-01-01

    Zebrafish (Danio rerio) embryos are increasingly used as a model for studying the function of the vertebrate innate immune system in host-pathogen interactions 1. The major cell types of the innate immune system, macrophages and neutrophils, develop during the first days of embryogenesis prior to the maturation of lymphocytes that are required for adaptive immune responses. The ease of obtaining large numbers of embryos, their accessibility due to external development, the optical transparency of embryonic and larval stages, a wide range of genetic tools, extensive mutant resources and collections of transgenic reporter lines, all add to the versatility of the zebrafish model. Salmonella enterica serovar Typhimurium (S. typhimurium) and Mycobacterium marinum can reside intracellularly in macrophages and are frequently used to study host-pathogen interactions in zebrafish embryos. The infection processes of these two bacterial pathogens are interesting to compare because S. typhimurium infection is acute and lethal within one day, whereas M. marinum infection is chronic and can be imaged up to the larval stage 2, 3. The site of micro-injection of bacteria into the embryo (Figure 1) determines whether the infection will rapidly become systemic or will initially remain localized. A rapid systemic infection can be established by micro-injecting bacteria directly into the blood circulation via the caudal vein at the posterior blood island or via the Duct of Cuvier, a wide circulation channel on the yolk sac connecting the heart to the trunk vasculature. At 1 dpf, when embryos at this stage have phagocytically active macrophages but neutrophils have not yet matured, injecting into the blood island is preferred. For injections at 2-3 dpf, when embryos also have developed functional (myeloperoxidase-producing) neutrophils, the Duct of Cuvier is preferred as the injection site. To study directed migration of myeloid cells towards local infections, bacteria can be injected into the tail muscle, otic vesicle, or hindbrain ventricle 4-6. In addition, the notochord, a structure that appears to be normally inaccessible to myeloid cells, is highly susceptible to local infection 7. A useful alternative for high-throughput applications is the injection of bacteria into the yolk of embryos within the first hours after fertilization 8. Combining fluorescent bacteria and transgenic zebrafish lines with fluorescent macrophages or neutrophils creates ideal circumstances for multi-color imaging of host-pathogen interactions. This video article will describe detailed protocols for intravenous and local infection of zebrafish embryos with S. typhimurium or M. marinum bacteria and for subsequent fluorescence imaging of the interaction with cells of the innate immune system. PMID:22453760

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

    E-print Network

    Bordenstein, Seth

    and methods, but not Abstract: 11,132 Number of references 30 #12;Abstract. Lateral transfer of mobile DNA that bacteriophage WO-B transfers laterally between infections of the same insect host. Lateral transfer between strains. Here we analyze bacterial and phage genes from two pairs of natural sympatric field isolates

  13. Genome-wide screen for temperature-regulated genes of the obligate intracellular bacterium, Rickettsia typhi

    PubMed Central

    Dreher-Lesnick, Sheila M; Ceraul, Shane M; Rahman, M Sayeedur; Azad, Abdu F

    2008-01-01

    Background The ability of rickettsiae to survive in multiple eukaryotic host environments provides a good model for studying pathogen-host molecular interactions. Rickettsia typhi, the etiologic agent of murine typhus, is a strictly intracellular gram negative ?-proteobacterium, which is transmitted to humans by its arthropod vector, the oriental rat flea, Xenopsylla cheopis. Thus, R. typhi must cycle between mammalian and flea hosts, two drastically different environments. We hypothesize that temperature plays a role in regulating host-specific gene expression, allowing R. typhi to survive in mammalian and arthropod hosts. In this study, we used Affymetrix microarrays to screen for temperature-induced genes upon a temperature shift from 37°C to 25°C, mimicking the two different host temperatures in vitro. Results Temperature-responsive genes belonged to multiple functional categories including among others, transcription, translation, posttranslational modification/protein turnover/chaperones and intracellular trafficking and secretion. A large number of differentially expressed genes are still poorly characterized, and either have no known function or are not in the COG database. The microarray results were validated with quantitative real time RT-PCR. Conclusion This microarray screen identified various genes that were differentially expressed upon a shift in temperature from 37°C to 25°C. Further characterization of the identified genes may provide new insights into the ability of R. typhi to successfully transition between its mammalian and arthropod hosts. PMID:18412961

  14. Immunological mechanisms contributing to the double burden of diabetes and intracellular bacterial infections.

    PubMed

    Hodgson, Kelly; Morris, Jodie; Bridson, Tahnee; Govan, Brenda; Rush, Catherine; Ketheesan, Natkunam

    2015-02-01

    Diabetes has been recognized as an important risk factor for a variety of intracellular bacterial infections, but research into the dysregulated immune mechanisms contributing to the impaired host-pathogen interactions is in its infancy. Diabetes is characterized by a chronic state of low-grade inflammation due to activation of pro-inflammatory mediators and increased formation of advanced glycation end products. Increased oxidative stress also exacerbates the chronic inflammatory processes observed in diabetes. The reduced phagocytic and antibacterial activity of neutrophils and macrophages provides an intracellular niche for the pathogen to replicate. Phagocytic and antibacterial dysfunction may be mediated directly through altered glucose metabolism and oxidative stress. Furthermore, impaired activation of natural killer cells contributes to decreased levels of interferon-?, required for promoting macrophage antibacterial mechanisms. Together with impaired dendritic cell function, this impedes timely activation of adaptive immune responses. Increased intracellular oxidation of antigen-presenting cells in individuals with diabetes alters the cytokine profile generated and the subsequent balance of T-cell immunity. The establishment of acute intracellular bacterial infections in the diabetic host is associated with impaired T-cell-mediated immune responses. Concomitant to the greater intracellular bacterial burden and potential cumulative effect of chronic inflammatory processes, late hyper-inflammatory cytokine responses are often observed in individuals with diabetes, contributing to systemic pathology. The convergence of intracellular bacterial infections and diabetes poses new challenges for immunologists, providing the impetus for multidisciplinary research. PMID:25262977

  15. Motor-driven intracellular transport powers bacterial gliding motility.

    PubMed

    Sun, Mingzhai; Wartel, Morgane; Cascales, Eric; Shaevitz, Joshua W; Mignot, Tâm

    2011-05-01

    Protein-directed intracellular transport has not been observed in bacteria despite the existence of dynamic protein localization and a complex cytoskeleton. However, protein trafficking has clear potential uses for important cellular processes such as growth, development, chromosome segregation, and motility. Conflicting models have been proposed to explain Myxococcus xanthus motility on solid surfaces, some favoring secretion engines at the rear of cells and others evoking an unknown class of molecular motors distributed along the cell body. Through a combination of fluorescence imaging, force microscopy, and genetic manipulation, we show that membrane-bound cytoplasmic complexes consisting of motor and regulatory proteins are directionally transported down the axis of a cell at constant velocity. This intracellular motion is transmitted to the exterior of the cell and converted to traction forces on the substrate. Thus, this study demonstrates the existence of a conserved class of processive intracellular motors in bacteria and shows how these motors have been adapted to produce cell motility. PMID:21482768

  16. 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

  17. Biological Properties and Cell Tropism of Chp2, a Bacteriophage of the Obligate Intracellular Bacterium Chlamydophila abortus

    PubMed Central

    Everson, J. S.; Garner, S. A.; Fane, B.; Liu, B.-L.; Lambden, P. R.; Clarke, I. N.

    2002-01-01

    A number of bacteriophages belonging to the Microviridae have been described infecting chlamydiae. Phylogenetic studies divide the Chlamydiaceae into two distinct genera, Chlamydia and Chlamydophila, containing three and six different species, respectively. In this work we investigated the biological properties and host range of the recently described bacteriophage Chp2 that was originally discovered in Chlamydophila abortus. The obligate intracellular development cycle of chlamydiae has precluded the development of quantitative approaches to assay bacteriophage infectivity. Thus, we prepared hybridomas secreting monoclonal antibodies (monoclonal antibodies 40 and 55) that were specific for Chp2. We demonstrated that Chp2 binds both C. abortus elementary bodies and reticulate bodies in an enzyme-linked immunosorbent assay. Monoclonal antibodies 40 and 55 also detected bacteriophage Chp2 antigens in chlamydia-infected eukaryotic cells. We used these monoclonal antibodies to monitor the ability of Chp2 to infect all nine species of chlamydiae. Chp2 does not infect members of the genus Chlamydia (C. trachomatis, C. suis, or C. muridarum). Chp2 can infect C. abortus, C. felis, and C. pecorum but is unable to infect other members of this genus, including C. caviae and C. pneumoniae, despite the fact that these chlamydial species support the replication of very closely related bacteriophages. PMID:11976304

  18. Evolution to a chronic disease niche correlates with increased sensitivity to tryptophan availability for the obligate intracellular bacterium Chlamydia pneumoniae.

    PubMed

    Huston, Wilhelmina M; Barker, Christopher J; Chacko, Anu; Timms, Peter

    2014-06-01

    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

  19. 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

  20. Host-Directed Antimicrobial Drugs with Broad-Spectrum Efficacy against Intracellular Bacterial Pathogens

    PubMed Central

    Czy?, Daniel M.; Potluri, Lakshmi-Prasad; Jain-Gupta, Neeta; Riley, Sean P.; Martinez, Juan J.; Steck, Theodore L.; Crosson, Sean; Gabay, Joëlle E.

    2014-01-01

    ABSTRACT We sought a new approach to treating infections by intracellular bacteria, namely, by altering host cell functions that support their growth. We screened a library of 640 Food and Drug Administration (FDA)-approved compounds for agents that render THP-1 cells resistant to infection by four intracellular pathogens. We identified numerous drugs that are not antibiotics but were highly effective in inhibiting intracellular bacterial growth with limited toxicity to host cells. These compounds are likely to target three kinds of host functions: (i) G protein-coupled receptors, (ii) intracellular calcium signals, and (iii) membrane cholesterol distribution. The compounds that targeted G protein receptor signaling and calcium fluxes broadly inhibited Coxiella burnetii, Legionella pneumophila, Brucella abortus, and Rickettsia conorii, while those directed against cholesterol traffic strongly attenuated the intracellular growth of C. burnetii and L. pneumophila. These pathways probably support intracellular pathogen growth so that drugs that perturb them may be therapeutic candidates. Combining host- and pathogen-directed treatments is a strategy to decrease the emergence of drug-resistant intracellular bacterial pathogens. PMID:25073644

  1. 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

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

    E-print Network

    Higgins, Darren

    , such as Myco- bacterium tuberculosis, Salmonella enterica serovar Typhi, Lis- teria monocytogenes (Lm that effectively stimulate protective immune responses yet do not cause disease, especially in immunocompromised is a facultative intracellular bacterial pathogen of humans and animals (7) and has been extensively studied

  3. 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

  4. Hydrogen peroxide staining to visualize intracellular bacterial infections of seedling root cells.

    PubMed

    White, James F; Torres, Mónica S; Somu, Mohini P; Johnson, Holly; Irizarry, Ivelisse; Chen, Qiang; Zhang, Ning; Walsh, Emily; Tadych, Mariusz; Bergen, Marshall

    2014-08-01

    Visualization of bacteria in living plant cells and tissues is often problematic due to lack of stains that pass through living plant cell membranes and selectively stain bacterial cells. In this article, we report the use of 3,3'-diaminobenzidine tetrachloride (DAB) to stain hydrogen peroxide associated with bacterial invasion of eukaryotic cells. Tissues were counterstained with aniline blue/lactophenol to stain protein in bacterial cells. Using this staining method to visualize intracellular bacterial (Burkholderia gladioli) colonization of seedling roots of switch grass (Panicum virgatum), we compared bacterial free seedling roots and those inoculated with the bacterium. To further assess application of the technique in multiple species of vascular plants, we examined vascular plants for seedling root colonization by naturally occurring seed-transmitted bacteria. Colonization by bacteria was only observed to occur within epidermal (including root hairs) and cortical cells of root tissues, suggesting that bacteria may not be penetrating deeply into root tissues. DAB/peroxidase with counter stain aniline blue/lactophenol was effective in penetration of root cells to selectively stain bacteria. Furthermore, this stain combination permitted the visualization of the bacterial lysis process. Before any evidence of H2 O2 staining, intracellular bacteria were seen to stain blue for protein content with aniline blue/lactophenol. After H2 O2 staining became evident, bacteria were often swollen, without internal staining by aniline blue/lactophenol; this suggests loss of protein content. This staining method was effective for seedling root tissues; however, it was not effective at staining bacteria in shoot tissues due to poor penetration. PMID:24825573

  5. Genomic revelations of a mutualism: the pea aphid and its obligate bacterial symbiont.

    PubMed

    Shigenobu, Shuji; Wilson, Alex C C

    2011-04-01

    The symbiosis of the pea aphid Acyrthosphion pisum with the bacterium Buchnera aphidicola APS represents the best-studied insect obligate symbiosis. Here we present a refined picture of this symbiosis by linking pre-genomic observations to new genomic data that includes the complete genomes of the eukaryotic and prokaryotic symbiotic partners. In doing so, we address four issues central to understanding the patterns and processes operating at the A. pisum/Buchnera APS interface. These four issues include: (1) lateral gene transfer, (2) host immunity, (3) symbiotic metabolism, and (4) regulation. PMID:21390549

  6. The Salmonella effector AvrA mediates bacterial intracellular survival during infection in vivo

    PubMed Central

    Wu, Huixia; Jones, Rheinallt M.; Neish, Andrew S.

    2011-01-01

    SUMMARY The enteric pathogen Salmonella typhimurium secretes the preformed AvrA effector protein into host cells. This acetyltransferase has been shown to modulate mammalian intestinal immune and survival responses by inhibition of JNK MAPK. To study the role of this effector in natural enteric infection, we used a mouse model to compare wild type Salmonella typhimurium to an isogenic AvrA null Salmonella mutant. Salmonella lacking AvrA induced increased intestinal inflammation, more intense systemic cytokine responses, and increased apoptosis in epithelial cells. Increased apoptosis was also observed in extra epithelial macrophages. AvrA null infected mice consistently showed higher bacterial burden within mucosal lymphoid tissues, spleen and liver by 5 days post infection, which indicated a more severe clinical course. To study the molecular mechanisms involved, recombinant adenoviruses expressing AvrA or mutant AvrA proteins were constructed, which showed appropriate expression and mediated the expected inhibition of JNK signaling. Cultured epithelial cells and macrophages transduced with AvrA expressing adenovirus were protected from apoptosis induced by exogenous stimuli. In conclusion, the results demonstrated that Salmonella AvrA modulates survival of infected macrophages likely via JNK suppression, and prevents macrophage death and rapid bacterial dissemination. AvrA suppression of apoptosis in infected macrophages may allow for establishment of a stable intracellular niche typical of intracellular pathogens. PMID:21899703

  7. Two apextrin-like proteins mediate extracellular and intracellular bacterial recognition in amphioxus.

    PubMed

    Huang, Guangrui; Huang, Shengfeng; Yan, Xinyu; Yang, Ping; Li, Jun; Xu, Weiya; Zhang, Lingling; Wang, Ruihua; Yu, Yingcai; Yuan, Shaochun; Chen, Shangwu; Luo, Guangbin; Xu, Anlong

    2014-09-16

    Animals exploit different germ-line-encoded proteins with various domain structures to detect the signature molecules of pathogenic microbes. These molecules are known as pathogen-associated molecular patterns (PAMPs), and the host proteins that react with PAMPs are called pattern recognition proteins (PRPs). Here, we present a novel type of protein domain structure capable of binding to bacterial peptidoglycan (PGN) and the minimal PGN motif muramyl dipeptide (MDP). This domain is designated as apextrin C-terminal domain (ApeC), and its presence was confirmed in several invertebrate phyla and subphyla. Two apextrin-like proteins (ALP1 and ALP2) were identified in a basal chordate, the Japanese amphioxus Branchiostoma japonicum (bj). bjALP1 is a mucosal effector secreted into the gut lumen to agglutinate the Gram-positive bacterium Staphylococcus aureus via PGN binding. Neutralization of secreted bjALP1 by anti-bjALP1 monoclonal antibodies caused serious damage to the gut epithelium and rapid death of the animals after bacterial infection. bjALP2 is an intracellular PGN sensor that binds to TNF receptor-associated factor 6 (TRAF6) and prevents TRAF6 from self-ubiquitination and hence from NF-?B activation. MDP was found to compete with TRAF6 for bjALP2, which released TRAF6 to activate the NF-?B pathway. BjALP1 and bjALP2 therefore play distinct and complementary functions in amphioxus gut mucosal immunity. In conclusion, discovery of the ApeC domain and the functional analyses of amphioxus ALP1 and ALP2 allowed us to define a previously undocumented type of PRP that is represented across different animal phyla. PMID:25187559

  8. Two apextrin-like proteins mediate extracellular and intracellular bacterial recognition in amphioxus

    PubMed Central

    Huang, Guangrui; Huang, Shengfeng; Yan, Xinyu; Yang, Ping; Li, Jun; Xu, Weiya; Zhang, Lingling; Wang, Ruihua; Yu, Yingcai; Yuan, Shaochun; Chen, Shangwu; Luo, Guangbin; Xu, Anlong

    2014-01-01

    Animals exploit different germ-line-encoded proteins with various domain structures to detect the signature molecules of pathogenic microbes. These molecules are known as pathogen-associated molecular patterns (PAMPs), and the host proteins that react with PAMPs are called pattern recognition proteins (PRPs). Here, we present a novel type of protein domain structure capable of binding to bacterial peptidoglycan (PGN) and the minimal PGN motif muramyl dipeptide (MDP). This domain is designated as apextrin C-terminal domain (ApeC), and its presence was confirmed in several invertebrate phyla and subphyla. Two apextrin-like proteins (ALP1 and ALP2) were identified in a basal chordate, the Japanese amphioxus Branchiostoma japonicum (bj). bjALP1 is a mucosal effector secreted into the gut lumen to agglutinate the Gram-positive bacterium Staphylococcus aureus via PGN binding. Neutralization of secreted bjALP1 by anti-bjALP1 monoclonal antibodies caused serious damage to the gut epithelium and rapid death of the animals after bacterial infection. bjALP2 is an intracellular PGN sensor that binds to TNF receptor-associated factor 6 (TRAF6) and prevents TRAF6 from self-ubiquitination and hence from NF-?B activation. MDP was found to compete with TRAF6 for bjALP2, which released TRAF6 to activate the NF-?B pathway. BjALP1 and bjALP2 therefore play distinct and complementary functions in amphioxus gut mucosal immunity. In conclusion, discovery of the ApeC domain and the functional analyses of amphioxus ALP1 and ALP2 allowed us to define a previously undocumented type of PRP that is represented across different animal phyla. PMID:25187559

  9. Novel bioactive hydrophobic gentamicin carriers for the treatment of intracellular bacterial infections

    Microsoft Academic Search

    Edurne Imbuluzqueta; Elisa Elizondo; Carlos Gamazo; Evelyn Moreno-Calvo; Jaume Veciana; Nora Ventosa; María J. Blanco-Prieto

    2011-01-01

    Gentamicin (GEN) is an aminoglycoside antibiotic with a potent antibacterial activity against a wide variety of bacteria. However, its poor cellular penetration limits its use in the treatment of infections caused by intracellular pathogens. One potential strategy to overcome this problem is the use of particulate carriers that can target the intracellular sites of infection. In this study GEN was

  10. TLR-Independent Type I Interferon Induction in Response to an Extracellular Bacterial Pathogen via Intracellular Recognition of Its DNA

    PubMed Central

    Charrel-Dennis, Marie; Latz, Eicke; Halmen, Kristen A.; Trieu-Cuot, Patrick; Fitzgerald, Katherine A.; Kasper, Dennis L.; Golenbock, Douglas T.

    2011-01-01

    SUMMARY Type I interferon (IFN) is an important host defense cytokine against intracellular pathogens, mainly viruses. In assessing IFN production in response to group B streptococcus (GBS), we find that IFN-? was produced by macrophages upon stimulation with both heat-killed and live GBS. Exposure of macrophages to heat-killed GBS activated a Toll-like receptor (TLR)-dependent pathway, whereas live GBS activated a TLR/NOD/RIG-like receptor (RLR)-independent pathway. This latter pathway required bacterial phagocytosis, proteolytic bacterial degradation, and phagolysosomal membrane destruction by GBS pore-forming toxins, leading to the release of bacterial DNA into the cytosol. GBS DNA in the cytosol induced IFN-? production via a pathway dependent on the activation of the serine-threonine kinase TBK1 and phosphorylation of the transcription factor IRF3. Thus, activation of IFN-?/-? production during infection with GBS, commonly considered an extracellular pathogen, appears to result from the interaction of GBS DNA with a putative intracellular DNA sensor or receptor. PMID:19064255

  11. A Rickettsia Genome Overrun by Mobile Genetic Elements Provides Insight into the Acquisition of Genes Characteristic of an Obligate Intracellular Lifestyle

    PubMed Central

    Joardar, Vinita; Williams, Kelly P.; Driscoll, Timothy; Hostetler, Jessica B.; Nordberg, Eric; Shukla, Maulik; Walenz, Brian; Hill, Catherine A.; Nene, Vishvanath M.; Azad, Abdu F.; Sobral, Bruno W.; Caler, Elisabet

    2012-01-01

    We present the draft genome for the Rickettsia endosymbiont of Ixodes scapularis (REIS), a symbiont of the deer tick vector of Lyme disease in North America. Among Rickettsia species (Alphaproteobacteria: Rickettsiales), REIS has the largest genome sequenced to date (>2 Mb) and contains 2,309 genes across the chromosome and four plasmids (pREIS1 to pREIS4). The most remarkable finding within the REIS genome is the extraordinary proliferation of mobile genetic elements (MGEs), which contributes to a limited synteny with other Rickettsia genomes. In particular, an integrative conjugative element named RAGE (for Rickettsiales amplified genetic element), previously identified in scrub typhus rickettsiae (Orientia tsutsugamushi) genomes, is present on both the REIS chromosome and plasmids. Unlike the pseudogene-laden RAGEs of O. tsutsugamushi, REIS encodes nine conserved RAGEs that include F-like type IV secretion systems similar to that of the tra genes encoded in the Rickettsia bellii and R. massiliae genomes. An unparalleled abundance of encoded transposases (>650) relative to genome size, together with the RAGEs and other MGEs, comprise ?35% of the total genome, making REIS one of the most plastic and repetitive bacterial genomes sequenced to date. We present evidence that conserved rickettsial genes associated with an intracellular lifestyle were acquired via MGEs, especially the RAGE, through a continuum of genomic invasions. Robust phylogeny estimation suggests REIS is ancestral to the virulent spotted fever group of rickettsiae. As REIS is not known to invade vertebrate cells and has no known pathogenic effects on I. scapularis, its genome sequence provides insight on the origin of mechanisms of rickettsial pathogenicity. PMID:22056929

  12. Autophagosomes induced by a bacterial Beclin 1 binding protein facilitate obligatory intracellular infection

    PubMed Central

    Niu, Hua; Xiong, Qingming; Yamamoto, Akitsugu; Hayashi-Nishino, Mitsuko; Rikihisa, Yasuko

    2012-01-01

    Autophagy, a cytoplasmic catabolic process, plays a critical role in defense against intracellular infection. In turn, evasion or inhibition of autophagy has emerged as an important virulence factor for intracellular pathogens. However, Anaplasma phagocytophilum, the obligatory intracellular bacterium that causes human granulocytic anaplasmosis, replicates in the membrane-bound compartment resembling early autophagosome. Here, we found that Anaplasma translocated substrate 1 (Ats-1), a type IV secretion effector, binds Beclin 1, a subunit of the class III PI3K and Atg14L, and it nucleates autophagosomes with markers of omegasomes, double FYVE-containing protein 1, Atg14L, and LC3. Ats-1 autophagy induction did not activate the starvation signaling pathway of mammalian target of rapamycin. These autophagy proteins were also localized to the Anaplasma inclusion. Ectopically expressed Ats-1 targeted the Anaplasma inclusions and enhanced infection, whereas host cytoplasmic delivery of anti–Ats-1 or Beclin 1 depletion by siRNA suppressed the infection; beclin 1 heterozygous-deficient mice were resistant to Anaplasma infection. Furthermore, Anaplasma growth arrest by the class III PI3K inhibitor 3-methyladenine was alleviated by essential amino acid supplementation. Thus, Anaplasma actively induces autophagy by secreting Ats-1 that hijacks the Beclin 1-Atg14L autophagy initiation pathway likely to acquire host nutrients for its growth. PMID:23197835

  13. Cyclic di-GMP as an Intracellular Signal Regulating Bacterial Biofilm Formation

    Microsoft Academic Search

    John M. Dow; Yvonne Fouhy

    Cyclic di-GMP is a novel second messenger in bacteria that was first described as an alloste- ric activator of cellulose synthase in Gluconacetobacter xylinus. It is now established that this nucleotide regulates a range of functions including developmental transitions, aggregative behavior, adhesion, biofilm formation and virulence in diverse bacteria. The level of cyclic di-GMP in bacterial cells is influenced by

  14. A Salmonella Small Non-Coding RNA Facilitates Bacterial Invasion and Intracellular Replication by Modulating the Expression of Virulence Factors

    PubMed Central

    Gong, Hao; Vu, Gia-Phong; Bai, Yong; Chan, Elton; Wu, Ruobin; Yang, Edward; Liu, Fenyong; Lu, Sangwei

    2011-01-01

    Small non-coding RNAs (sRNAs) that act as regulators of gene expression have been identified in all kingdoms of life, including microRNA (miRNA) and small interfering RNA (siRNA) in eukaryotic cells. Numerous sRNAs identified in Salmonella are encoded by genes located at Salmonella pathogenicity islands (SPIs) that are commonly found in pathogenic strains. Whether these sRNAs are important for Salmonella pathogenesis and virulence in animals has not been reported. In this study, we provide the first direct evidence that a pathogenicity island-encoded sRNA, IsrM, is important for Salmonella invasion of epithelial cells, intracellular replication inside macrophages, and virulence and colonization in mice. IsrM RNA is expressed in vitro under conditions resembling those during infection in the gastrointestinal tract. Furthermore, IsrM is found to be differentially expressed in vivo, with higher expression in the ileum than in the spleen. IsrM targets the mRNAs coding for SopA, a SPI-1 effector, and HilE, a global regulator of the expression of SPI-1 proteins, which are major virulence factors essential for bacterial invasion. Mutations in IsrM result in disregulation of expression of HilE and SopA, as well as other SPI-1 genes whose expression is regulated by HilE. Salmonella with deletion of isrM is defective in bacteria invasion of epithelial cells and intracellular replication/survival in macrophages. Moreover, Salmonella with mutations in isrM is attenuated in killing animals and defective in growth in the ileum and spleen in mice. Our study has shown that IsrM sRNA functions as a pathogenicity island-encoded sRNA directly involved in Salmonella pathogenesis in animals. Our results also suggest that sRNAs may represent a distinct class of virulence factors that are important for bacterial infection in vivo. PMID:21949647

  15. Attenuation of the Sensing Capabilities of PhoQ in Transition to Obligate Insect–Bacterial Association

    Microsoft Academic Search

    Mauricio Henriques Pontes; Kari Lyn Smith; Linda De Vooght; Jan Van Den Abbeele; Colin Dale

    2011-01-01

    Sodalis glossinidius, a maternally inherited endosymbiont of the tsetse fly, maintains genes encoding homologues of the PhoP-PhoQ two-component regulatory system. This two-component system has been extensively studied in facultative bacterial pathogens and is known to serve as an environmental magnesium sensor and a regulator of key virulence determinants. In the current study, we show that the inactivation of the response

  16. Drug Effects on Intracellular Mycobacteria Determined by Mass Spectrometric Analysis of the Na 1 toK 1 Ratios of Individual Bacterial Organisms

    Microsoft Academic Search

    MONIKA WIESE; ANDULRICH SEYDEL

    1996-01-01

    The successful establishment of a drug screening system for intracellular cultivable and noncultivable mycobacteria based on the mass spectrometric determination of bacterial viability is described. To compare drug efficacies on intra- and extracellular mycobacteria, the mycobacteria were subjected to drug treatment either after phagocytosis by the mouse macrophage cell line RAW 264.7 or in cell-free medium. After reiso- lation, their

  17. Actin filaments and the growth, movement, and spread of the intracellular bacterial parasite, Listeria monocytogenes

    PubMed Central

    1989-01-01

    Listeria monocytogenes was used as a model intracellular parasite to study stages in the entry, growth, movement, and spread of bacteria in a macrophage cell line. The first step in infection is phagocytosis of the Listeria, followed by the dissolution of the membrane surrounding the phagosome presumably mediated by hemolysin secreted by Listeria as nonhemolytic mutants remain in intact vacuoles. Within 2 h after infection, each now cytoplasmic Listeria becomes encapsulated by actin filaments, identified as such by decoration of the actin filaments with subfragment 1 of myosin. These filaments are very short. The Listeria grow and divide and the actin filaments rearrange to form a long tail (often 5 microns in length) extending from only one end of the bacterium, a "comet's tail," in which the actin filaments appear randomly oriented. The Listeria "comet" moves to the cell surface with its tail oriented towards the cell center and becomes incorporated into a cell extension with the Listeria at the tip of the process and its tail trailing into the cytoplasm behind it. This extension contacts a neighboring macrophage that phagocytoses the extension of the first macrophage. Thus, within the cytoplasm of the second macrophage is a Listeria with its actin tail surrounded by a membrane that in turn is surrounded by the phagosome membrane of the new host. Both these membranes are then solubilized by the Listeria and the cycle is repeated. Thus, once inside a host cell, the infecting Listeria and their progeny can spread from cell to cell by remaining intracellular and thus bypass the humoral immune system of the organism. To establish if actin filaments are essential for the spread of Listeria from cell to cell, we treated infected macrophages with cytochalasin D. The Listeria not only failed to spread, but most were found deep within the cytoplasm, rather than near the periphery of the cell. Thin sections revealed that the net of actin filaments is not formed nor is a "comet" tail produced. PMID:2507553

  18. Invasion of the Central Nervous System by Intracellular Bacteria

    PubMed Central

    Drevets, Douglas A.; Leenen, Pieter J. M.; Greenfield, Ronald A.

    2004-01-01

    Infection of the central nervous system (CNS) is a severe and frequently fatal event during the course of many diseases caused by microbes with predominantly intracellular life cycles. Examples of these include the facultative intracellular bacteria Listeria monocytogenes, Mycobacterium tuberculosis, and Brucella and Salmonella spp. and obligate intracellular microbes of the Rickettsiaceae family and Tropheryma whipplei. Unfortunately, the mechanisms used by intracellular bacterial pathogens to enter the CNS are less well known than those used by bacterial pathogens with an extracellular life cycle. The goal of this review is to elaborate on the means by which intracellular bacterial pathogens establish infection within the CNS. This review encompasses the clinical and pathological findings that pertain to the CNS infection in humans and includes experimental data from animal models that illuminate how these microbes enter the CNS. Recent experimental data showing that L. monocytogenes can invade the CNS by more than one mechanism make it a useful model for discussing the various routes for neuroinvasion used by intracellular bacterial pathogens. PMID:15084504

  19. A dominant function of CCaMK in intracellular accommodation of bacterial and fungal endosymbionts

    PubMed Central

    Hayashi, Teruyuki; Banba, Mari; Shimoda, Yoshikazu; Kouchi, Hiroshi; Hayashi, Makoto; Imaizumi-Anraku, Haruko

    2010-01-01

    In legumes, Ca2+/calmodulin-dependent protein kinase (CCaMK) is a component of the common symbiosis genes that are required for both root nodule (RN) and arbuscular mycorrhiza (AM) symbioses and is thought to be a decoder of Ca2+ spiking, one of the earliest cellular responses to microbial signals. A gain-of-function mutation of CCaMK has been shown to induce spontaneous nodulation without rhizobia, but the significance of CCaMK activation in bacterial and/or fungal infection processes is not fully understood. Here we show that a gain-of-function CCaMKT265D suppresses loss-of-function mutations of common symbiosis genes required for the generation of Ca2+ spiking, not only for nodule organogenesis but also for successful infection of rhizobia and AM fungi, demonstrating that the common symbiosis genes upstream of Ca2+ spiking are required solely to activate CCaMK. In RN symbiosis, however, CCaMKT265D induced nodule organogenesis, but not rhizobial infection, on Nod factor receptor (NFRs) mutants. We propose a model of symbiotic signaling in host legume plants, in which CCaMK plays a key role in the coordinated induction of infection thread formation and nodule organogenesis. PMID:20409002

  20. 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

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

    PubMed

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

    2014-06-01

    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, 72h 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

  2. Self-assembling, protein-based intracellular bacterial organelles: emerging vehicles for encapsulating, targeting and delivering therapeutical cargoes

    PubMed Central

    2011-01-01

    Many bacterial species contain intracellular nano- and micro-compartments consisting of self-assembling proteins that form protein-only shells. These structures are built up by combinations of a reduced number of repeated elements, from 60 repeated copies of one unique structural element self-assembled in encapsulins of 24 nm to 10,000-20,000 copies of a few protein species assembled in a organelle of around 100-150 nm in cross-section. However, this apparent simplicity does not correspond to the structural and functional sophistication of some of these organelles. They package, by not yet definitely solved mechanisms, one or more enzymes involved in specific metabolic pathways, confining such reactions and sequestering or increasing the inner concentration of unstable, toxics or volatile intermediate metabolites. From a biotechnological point of view, we can use the self assembling properties of these particles for directing shell assembling and enzyme packaging, mimicking nature to design new applications in biotechnology. Upon appropriate engineering of the building blocks, they could act as a new family of self-assembled, protein-based vehicles in Nanomedicine to encapsulate, target and deliver therapeutic cargoes to specific cell types and/or tissues. This would provide a new, intriguing platform of microbial origin for drug delivery. PMID:22046962

  3. Institutional obligation

    SciTech Connect

    Rowan, S.S.; Berwager, S.D. (Bonneville Power Administration, Portland, OR (US))

    1988-01-01

    The institutional obligation is to act to meet primary responsibilities in the face of risks. There are risks involved in taking action, both of a quantifiable and unquantifiable nature. This paper explores weighing the risks, choosing approaches that balance primary obligations with broader ones, and presenting ethical philosophies upon which policies and strategies are based. Federal government organizations and utilities--and Bonneville Power Administration qualifies as both--have a variety of responsibilities to the public they serve. The common responsibility is that of service; for Bonneville the primary responsibility is to serve the energy related needs. It is this primary institutional obligation, as it relates to other responsibilities--and the resulting strategy for handling indoor air quality in Bonneville's new homes program--that this paper examines.

  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. A Bacterial Indole3-acetyl-L-aspartic Acid Hydrolase Inhibits Mung Bean ( Vigna radiata L.) Seed Germination Through Arginine-rich Intracellular Delivery

    Microsoft Academic Search

    Kevin Liu; Han-Jung Lee; Sio San Leong; Chen-Lun Liu; Jyh-Ching Chou

    2007-01-01

    Indole-3-acetyl-L-aspartic acid (IAA-Asp) is a natural product in many plant species and plays many important roles in auxin\\u000a metabolism and plant physiology. IAA-Asp hydrolysis activity is, therefore, believed to affect plant physiology through changes\\u000a in IAA metabolism in plants. We applied a newly discovered technique, arginine-rich intracellular delivery (AID), to deliver\\u000a a bacterial IAA-Asp hydrolase into cells of mung bean

  6. The pleiotropic transcriptional response of Mycobacterium tuberculosis to vitamin C is robust and overlaps with the bacterial response to multiple intracellular stresses.

    PubMed

    Sikri, Kriti; Batra, Sakshi Dhingra; Nandi, Malobi; Kumari, Priyanka; Taneja, Neetu Kumra; Tyagi, Jaya Sivaswami

    2015-04-01

    Mycobacterium tuberculosis (Mtb) owes its success as a pathogen in large measure to its ability to exist in a persistent state of 'dormancy' resulting in a lifelong latent tuberculosis (TB) infection. An understanding of bacterial adaptation during dormancy will help in devising approaches to counter latent TB infection. In vitro models have provided valuable insights into bacterial adaptation; however, they have limitations because they do not disclose the bacterial response to the intracellular environment wherein the bacteria are simultaneously exposed to multiple stresses. We describe the pleiotropic response of Mtb in the vitamin C (vit C) model of dormancy developed in our laboratory. Vit C mediates a rapid regulation of genes representing ~14?% of the genome in Mtb cultures. The upregulated genes were better represented in lipid, intermediary metabolism and regulatory protein categories. The downregulated genes mainly related to virulence, detoxification, information pathways and cell wall processes. A comparison of this response to that in other models indicates that vit C generates a multiple-stress environment for axenic Mtb cultures that resembles a macrophage-like environment. The bacterial response to vit C resembles responses to gaseous stresses such as hypoxia and nitric oxide, oxidative and nitrosative stresses, nutrient starvation and, notably, the activated macrophage environment itself. These responses demonstrate that the influence of vit C on Mtb gene expression extends well beyond the DevR dormancy regulon. A detailed characterization of the response to vit C is expected to disclose useful strategies to counter the adaptive mechanisms essential to Mtb dormancy. PMID:25645949

  7. OppA of Listeria monocytogenes, an Oligopeptide-Binding Protein Required for Bacterial Growth at Low Temperature and Involved in Intracellular Survival

    PubMed Central

    Borezee, Elise; Pellegrini, Elisabeth; Berche, Patrick

    2000-01-01

    We identified a new oligopeptide permease operon in the pathogen Listeria monocytogenes. This opp operon consists of five genes (oppA, oppB, oppC, oppD, and oppF) and displays the same genetic organization as those of several bacterial species. The first gene of this operon, oppA, encodes a 62-kDa protein sharing 33% identity with OppA of Bacillus subtilis and is expressed predominantly during exponential growth. The function of oppA was studied by constructing an oppA deletion mutant. The phenotype analysis of this mutant revealed that OppA mediates the transport of oligopeptides and is required for bacterial growth at low temperature. The wild-type phenotype was restored by complementing the mutant with oppA. We also found that OppA is involved in intracellular survival in macrophages and in bacterial growth in organs of mice infected with L. monocytogenes, although the level of virulence was not altered in the mutant. These results show the major role of OppA in the uptake of oligopeptides and the pleiotropic effects of this oligopeptide-binding protein on the behavior of this pathogen in the environment and in its host. PMID:11083832

  8. High-Affinity Zn2+ Uptake System ZnuABC Is Required for Bacterial Zinc Homeostasis in Intracellular Environments and Contributes to the Virulence of Salmonella enterica?

    PubMed Central

    Ammendola, Serena; Pasquali, Paolo; Pistoia, Claudia; Petrucci, Paola; Petrarca, Patrizia; Rotilio, Giuseppe; Battistoni, Andrea

    2007-01-01

    To investigate the relevance of zinc in host-pathogen interactions, we have constructed Salmonella enterica mutant strains in which the znuA gene, which encodes the periplasmic component of the ZnuABC high-affinity Zn2+ transporter, was deleted. This mutation does not alter the ability of Salmonella to grow in rich media but drastically reduces its ability to multiply in media deprived of zinc. In agreement with this phenotype, ZnuA accumulates only in bacteria cultivated in environments poor in zinc. In spite of the nearly millimolar intracellular concentration of zinc, we have found that znuA is highly expressed in intracellular salmonellae recovered either from cultivated cells or from the spleens of infected mice. We have also observed that znuA mutants are impaired in their ability to grow in Caco-2 epithelial cells and that bacteria starved for zinc display decreased ability to multiply in phagocytes. A dramatic reduction in the pathogenicity of the znuA mutants was observed in Salmonella-susceptible (BALB/c) or Salmonella-resistant (DBA-2) mice infected intraperitoneally or orally. This study shows that the amount of free metals available for bacterial growth within the infected animal is limited, despite the apparent elevated concentration of free metals within cells and in plasma and suggests that Salmonella exploits the ZnuABC zinc transporter to maximize zinc availability in such conditions. These results shed new light on the complex functions of zinc in vertebrate and bacterial physiology and pave the way for a better comprehension of pathogenic mechanisms in Salmonella infections. PMID:17923515

  9. Biological and antibacterial activities of the natural herb Houttuynia cordata water extract against the intracellular bacterial pathogen salmonella within the RAW 264.7 macrophage.

    PubMed

    Kim, Gon Sup; Kim, Dong Hyeok; Lim, Jeong Ju; Lee, Jin Ju; Han, Dae Yong; Lee, Whi Min; Jung, Won Chul; Min, Won Gi; Won, Chung Gil; Rhee, Man Hee; Lee, Hu Jang; Kim, Suk

    2008-11-01

    Salmonellosis is a major bacterial zoonosis that causes a variety of disease syndromes, from self-limiting enteritis to fatal infection in animals and food-borne infection and typhoid fever in humans. Recently, the emergence of multidrug-resistant strains of Salmonella sp. has caused more serious problems in public health. The present study investigated the antibacterial effects of Houttuynia cordata water extract (HCWE) against murine salmonellosis. In RAW 264.7 cells, there was no detectable cytotoxic effect of HCWE at any concentration between 25 and 100 microg/ml after 8-h incubation. The antibacterial activity of HCWE was then examined in a Salmonella enterica serovar (Salmonella typhimurium), and was found to increase in a dose-dependent manner at concentrations from 25 to 100 microg/ml during 8-h incubation. HCWE also affected RAW 264.7 cells including morphologic change and bacterial uptake, but there was no significant difference in bacterial replication in RAW 264.7 cells. With HCWE alone, nitric oxide (NO) production by RAW 264.7 cells did not increase, but when RAW 264.7 cells were infected by S. typhimurium, with or without HCWE, NO production with HCWE was 2-fold higher than that without HCWE. Treatment with HCWE did not affect inducible NO synthase (iNOS) mRNA expression by RAW 264.7 cells, but when RAW 264.7 cells with HCWE were infected by S. typhimurium, iNOS mRNA expression was increased during 8-h incubation. Furthermore, HCWE showed virulence reduction effects in S. typhimurium-infected BALB/c mice. After a lethal dose of S. typhimurium, the mortality rate in the HCWE untreated group was 100% at 7 d, but the HCWE 25, 50, and 100 microg/ml groups survived until 11, 17, and 23 d, respectively. These data suggest that HCWE is stable and beneficial in the treatment of bacterial infection including intracellularly replicating pathogens and may solve antimicrobial misuse and overuse. PMID:18981565

  10. A genomic island present along the bacterial chromosome of the Parachlamydiaceae UWE25, an obligate amoebal endosymbiont, encodes a potentially functional F-like conjugative DNA transfer system

    PubMed Central

    Greub, Gilbert; Collyn, François; Guy, Lionel; Roten, Claude-Alain

    2004-01-01

    Background The genome of Protochlamydia amoebophila UWE25, a Parachlamydia-related endosymbiont of free-living amoebae, was recently published, providing the opportunity to search for genomic islands (GIs). Results On the residual cumulative G+C content curve, a G+C-rich 19-kb region was observed. This sequence is part of a 100-kb chromosome region, containing 100 highly co-oriented ORFs, flanked by two 17-bp direct repeats. Two identical gly-tRNA genes in tandem are present at the proximal end of this genetic element. Several mobility genes encoding transposases and bacteriophage-related proteins are located within this chromosome region. Thus, this region largely fulfills the criteria of GIs. The G+C content analysis shows that several modules compose this GI. Surprisingly, one of them encodes all genes essential for F-like conjugative DNA transfer (traF, traG, traH, traN, traU, traW, and trbC), involved in sex pilus retraction and mating pair stabilization, strongly suggesting that, similarly to the other F-like operons, the parachlamydial tra unit is devoted to DNA transfer. A close relatedness of this tra unit to F-like tra operons involved in conjugative transfer is confirmed by phylogenetic analyses performed on concatenated genes and gene order conservation. These analyses and that of gly-tRNA distribution in 140 GIs suggest a proteobacterial origin of the parachlamydial tra unit. Conclusions A GI of the UWE25 chromosome encodes a potentially functional F-like DNA conjugative system. This is the first hint of a putative conjugative system in chlamydiae. Conjugation most probably occurs within free-living amoebae, that may contain hundreds of Parachlamydia bacteria tightly packed in vacuoles. Such a conjugative system might be involved in DNA transfer between internalized bacteria. Since this system is absent from the sequenced genomes of Chlamydiaceae, we hypothesize that it was acquired after the divergence between Parachlamydiaceae and Chlamydiaceae, when the Parachlamydia-related symbiont was an intracellular bacteria. It suggests that this heterologous DNA was acquired from a phylogenetically-distant bacteria sharing an amoebal vacuole. Since Parachlamydiaceae are emerging agents of pneumonia, this GI might be involved in pathogenicity. In future, conjugative systems might be developed as genetic tools for Chlamydiales. PMID:15615594

  11. Utilization of an Intracellular Bacterial Community Pathway in Klebsiella pneumoniae Urinary Tract Infection and the Effects of FimK on Type 1 Pilus Expression?

    PubMed Central

    Rosen, David A.; Pinkner, Jerome S.; Jones, Jennifer M.; Walker, Jennifer N.; Clegg, Steven; Hultgren, Scott J.

    2008-01-01

    Klebsiella pneumoniae is an important cause of urinary tract infection (UTI), but little is known about its pathogenesis in vivo. The pathogenesis of the K. pneumoniae cystitis isolate TOP52 was compared to that of the uropathogenic Escherichia coli (UPEC) isolate UTI89 in a murine cystitis model. Bladder and kidney titers of TOP52 were lower than those of UTI89 at early time points but similar at later time points. TOP52, like UTI89, formed biofilm-like intracellular bacterial communities (IBCs) within the murine bladder, albeit at significantly lower levels than UTI89. Additionally, filamentation of TOP52 was observed, a process critical for UTI89 evasion of neutrophil phagocytosis and persistence in the bladder. Thus, the IBC pathway is not specific to UPEC alone. We investigated if differences in type 1 pilus expression may explain TOP52's early defect in vivo. The type 1 pilus operon is controlled by recombinase-mediated (fimE, fimB, and fimX) phase variation of an invertible promoter element. We found that K. pneumoniae carries an extra gene of unknown function at the 3? end of its type 1 operon, fimK, and the genome lacks the recombinase fimX. A deletion mutant of fimK was constructed, and TOP52 ?fimK had higher titers and formed more IBCs in the murine cystitis model than wild type. The loss of fimK or expression of E. coli fimX from a plasmid in TOP52 resulted in a larger phase-ON population and higher expression levels of type 1 pili and gave TOP52 the ability to form type 1-dependent biofilms. Complementation with pfimK decreased type 1 pilus expression and biofilm formation of TOP52 ?fimK and decreased UTI89 biofilm formation. Thus, K. pneumoniae appears programmed for minimal expression of type 1 pili, which may explain, in part, why K. pneumoniae is a less prevalent etiologic agent of UTI than UPEC. PMID:18411285

  12. Strategies of genomic integration within insect-bacterial mutualisms

    PubMed Central

    Wernegreen, Jennifer J.

    2013-01-01

    Insects, the most diverse group of macroorganisms with 900,000 known species, have been a rich playground for the evolution of symbiotic associations. Symbionts of this enormous animal group include a range of microbial partners. Insects are prone to establishing relationships with intracellular bacteria, which include the most intimate, highly integrated mutualisms known in the biological world. In recent years, an explosion of genomic studies has offered new insights into the molecular, functional, and evolutionary consequences of these insect-bacterial partnerships. In this review, I highlight some insights from genome sequences of bacterial endosymbionts and select insect hosts. Notably, comparisons of facultative versus obligate bacterial mutualists have revealed distinct genome features representing different stages along a shared trajectory of genome reduction. Bacteria associated with the cedar aphid offer a snapshot of a transition from facultative to obligate mutualism, illustrating the genomic basis of this key step along the symbiotic spectrum. In addition, genomes of stable, dual bacterial symbionts reflect independent instances of astonishing metabolic integration. In these systems, synthesis of key nutrients, and perhaps basic cellular processes, require collaboration among co-residing bacteria and their insect host. These findings provide a launching point for a new era of genomic explorations of bacterial-animal symbioses. Future studies promise to reveal symbiotic strategies across a broad ecological and phylogenetic range, to clarify key transitions along a spectrum of interaction types, and to fuel new experimental approaches to dissect the mechanistic basis of intimate host-symbiont associations. PMID:22983037

  13. GRANDPARENTS' ENTITLEMENTS AND OBLIGATIONS

    PubMed Central

    Draper, Heather

    2013-01-01

    In this article, it is argued that grandparents' obligations originate from parental obligations (i.e from the relationship they have with their children, the parents of their grandchildren) and not from the role of grandparent per se, and any entitlements flow from the extent to which these obligations are met. The position defended is, therefore, that grandparents qua grandparents are not entitled to form or continue relationships with their grandchildren. A continuation of grandparent-grandchildren relationships may be in the interests of children, but the grandparental nature of the relationship is not decisive. What counts is the extent to which relationships children have with any adults who are not their parents are is significant to them. Sometimes, however, grandparents become parents or co-parents of their grandchildren. They then gain parental rights, and as such are as entitled, ceteris parius, as any parent to expect their relationship with the child to continue. The issue of grandparents' entitlements can come to the fore when parents separate, and grandparents are unhappy with the access they have to their grandchildren. Grandparents' obligations may become a particular issue when parents die, struggle, or fail to care for their children. This article focuses particularly on these kinds of circumstances. PMID:23718643

  14. Modals of Strong Obligation

    ERIC Educational Resources Information Center

    Matthews-Bresky, R. J. H.

    1977-01-01

    Discusses regularities and peculiarities in the use of the modal verbs of obligation "must,""need" and "should," also of the non-modals "have (got) to" and "need to." Agreements and differences in the use of the verbs are shown, with examples. Use of the various tense-forms is discussed. (IFS/WGA)

  15. Slc11a1 limits intracellular growth of Salmonella enterica sv. Typhimurium by promoting macrophage immune effector functions and impairing bacterial iron acquisition.

    PubMed

    Nairz, Manfred; Fritsche, Gernot; Crouch, Marie-Laure V; Barton, Howard C; Fang, Ferric C; Weiss, Günter

    2009-09-01

    The natural resistance-associated macrophage protein 1, Slc11a1, is a phagolysosomal transporter for protons and divalent ions including iron that confers host protection against diverse intracellular pathogens including Salmonella. We investigated and compared the regulation of iron homeostasis and immune function in RAW264.7 murine phagocytes stably transfected with non-functional Slc11a1 and functional Slc11a1 controls in response to an infection with Salmonella enterica serovar Typhimurium. We report that macrophages lacking functional Slc11a1 displayed an increased expression of transferrin receptor 1, resulting in enhanced acquisition of transferrin-bound iron. In contrast, cellular iron release mediated via ferroportin 1 was significantly lower in Salmonella-infected Slc11a1-negative macrophages in comparison with phagocytes bearing Slc11a1. Lack of Slc11a1 led to intracellular persistence of S. enterica serovar Typhimurium within macrophages, which was paralleled by a reduced formation of nitric oxide, tumour necrosis factor-alpha and interleukin-6 in Slc11a1-negative macrophages following Salmonella infection, whereas interleukin-10 production was increased. Moreover, Slc11a1-negative phagocytes exhibited higher cellular iron content, resulting in increased iron acquisition by intracellular Salmonella. Our observations indicate a bifunctional role for Slc11a1 within phagocytes. Slc11a restricts iron availability, which first augments pro-inflammatory macrophage effector functions and second concomitantly limits microbial iron access. PMID:19500110

  16. Flotillin-1 (Reggie-2) Contributes to Chlamydia pneumoniae Growth and Is Associated with Bacterial Inclusion

    PubMed Central

    Korhonen, Juha T.; Puolakkainen, Mirja; Häivälä, Reetta; Penttilä, Tuula; Haveri, Anu; Markkula, Eveliina

    2012-01-01

    Chlamydiae are obligate intracellular pathogens replicating only inside the eukaryotic host. Here, we studied the effect of human flotillin-1 protein on Chlamydia pneumoniae growth in human line (HL) and A549 epithelial cell lines. RNA interference was applied to disrupt flotillin-1-mediated endocytosis. Host-associated bacteria were detected by quantitative PCR, and C. pneumoniae growth was evaluated by inclusion counts. C. pneumoniae attachment to host cells was unaffected, but bacterial intracellular growth was attenuated in the flotillin-1-silenced cells. By using confocal microscopy, we detected flotillin-1 colocalized with the inclusion membrane protein A (IncA) in the C. pneumoniae inclusion membranes. In addition, flotillin-1 was associated with IncA in detergent-resistant membrane microdomains (DRMs) in biochemical fractioning. These results suggest that flotillin-1 localizes to the C. pneumoniae inclusion membrane and plays an important role for intracellular growth of C. pneumoniae. PMID:22215737

  17. No organization without obligations: How to formalize collective obligation?

    E-print Network

    Dignum, Frank

    of autonomous agents interact to achieve a certain task, for example to ful#12;l an obligation directed) has the responsibility to bring about a certain situation (to express group liability, e.g. liability

  18. Obligately barophilic bacterium from the Mariana trench.

    PubMed Central

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

    1981-01-01

    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. Images PMID:6946468

  19. Endosymbiosis In Statu Nascendi: Close Phylogenetic RelationshipBetween Obligately Endosymbiotic and Obligately Free-LivingPolynucleobacter Strains (Betaproteobacteria)

    SciTech Connect

    Vannini, Claudia; Pockl, Matthias; Petroni, Giulio; Wu, Qinglong; Lang, Elke; Stackebrandt, Erko; Schrallhammer, Martina; Richardson, PaulM.; Hahn, Martin W.

    2006-07-21

    Bacterial strains affiliated to the phylogenetically shallowsubcluster C (PnecC) of the 28 Polynucleobacter cluster, which ischaracterized by a minimal 16S rRNA gene sequence similarity of approx.98.5 percent, have been reported to occur as obligate endosymbionts of 30ciliates (Euplotes spp.), as well as to occur as free-living cells in thepelagic zone of freshwater habitats. We investigated if these two groupsof closely related bacteria represent 32 strains fundamentally differingin lifestyle, or if they simply represent different stages of afacultative endosymbiotic lifestyle. The phylogenetic analysis of 16SrRNA gene and 16S34 23S ITS sequences of five endosymbiont strains fromtwo different Euplotes species and 40 pure culture strains demonstratedhost-species-specific clustering of the endosymbiont 36 sequences withinthe PnecC subcluster. The sequences of the endosymbionts showedcharacteristics indicating an obligate endosymbiotic lifestyle.Cultivation experiments 38 revealed fundamental differences inphysiological adaptations, and determination of the genome sizesindicated a slight size reduction in endosymbiotic strains. We concludethat the 40 two groups of PnecC bacteria represent obligately free-livingand obligately endosymbiotic strains, respectively, and do not representdifferent stages of the same complex lifecycle. 42 These closely relatedstrains occupy completely separated ecological niches. To our bestknowledge, this is the closest phylogenetic relationship between obligateendosymbionts and 44 obligately free-living bacteria everrevealed.

  20. Phenotypic characterization and 16S rDNA identification of culturable non-obligate halophilic bacterial communities from a hypersaline lake, La Sal del Rey, in extreme South Texas (USA)

    PubMed Central

    2012-01-01

    Background La Sal del Rey ("the King's Salt") is one of several naturally-occurring salt lakes in Hidalgo County, Texas and is part of the Lower Rio Grande Valley National Wildlife Refuge. The research objective was to isolate and characterize halophilic microorganisms from La Sal del Rey. Water samples were collected from the lake and a small creek that feeds into the lake. Soil samples were collected from land adjacent to the water sample locations. Sample salinity was determined using a refractometer. Samples were diluted and cultured on a synthetic saline medium to grow halophilic bacteria. The density of halophiles was estimated by viable plate counts. A collection of isolates was selected, gram-stained, tested for catalase, and characterized using API 20E® test strips. Isolates were putatively identified by sequencing the 16S rDNA. Carbon source utilization by the microbial community from each sample site was examined using EcoPlate™ assays and the carbon utilization total activity of the community was determined. Results Results showed that salinity ranged from 4 parts per thousand (ppt) at the lake water source to 420 ppt in water samples taken just along the lake shore. The density of halophilic bacteria in water samples ranged from 1.2 × 102 - 5.2 × 103 colony forming units per ml (cfu ml-1) whereas the density in soil samples ranged from 4.0 × 105 - 2.5 × 106 colony forming units per gram (cfu g-1). In general, as salinity increased the density of the bacterial community decreased. Microbial communities from water and soil samples were able to utilize 12 - 31 carbon substrates. The greatest number of substrates utilized was by water-borne communities compared to soil-based communities, especially at lower salinities. The majority of bacteria isolated were gram-negative, catalase-positive, rods. Biochemical profiles constructed from API 20E® test strips showed that bacterial isolates from low-salinity water samples (4 ppt) showed the greatest phenotypic diversity with regards to the types and number of positive tests from the strip. Isolates taken from water samples at the highest salinity (420 ppt) tended to be less diverse and have only a limited number of positive tests. Sequencing of 16S DNA displayed the presence of members of bacterial genera Bacillus, Halomonas, Pseudomonas, Exiguobacterium and others. The genus Bacillus was most commonly identified. None of the isolates were members of the Archaea probably due to dilution of salts in the samples. Conclusions The La Sal del Rey ecosystem supports a robust and diverse bacterial community despite the high salinity of the lake and soil. However, salinity does appear to a limiting factor with regards to the density and diversity of the bacterial communities that inhabit the lake and surrounding area. PMID:22480362

  1. Chlamydia trachomatis Intercepts Golgi-Derived Sphingolipids through a Rab14-Mediated Transport Required for Bacterial Development and Replication

    PubMed Central

    Capmany, Anahí; Damiani, María Teresa

    2010-01-01

    Chlamydia trachomatis are obligate intracellular bacteria that survive and replicate in a bacterial-modified phagosome called inclusion. As other intracellular parasites, these bacteria subvert the phagocytic pathway to avoid degradation in phagolysosomes and exploit trafficking pathways to acquire both energy and nutrients essential for their survival. Rabs are host proteins that control intracellular vesicular trafficking. Rab14, a Golgi-related Rab, controls Golgi to endosomes transport. Since Chlamydia establish a close relationship with the Golgi apparatus, the recruitment and participation of Rab14 on inclusion development and bacteria growth were analyzed. Time course analysis revealed that Rab14 associated with inclusions by 10 h post infection and was maintained throughout the entire developmental cycle. The recruitment was bacterial protein synthesis-dependent but independent of microtubules and Golgi integrity. Overexpression of Rab14 dominant negative mutants delayed inclusion enlargement, and impaired bacteria replication as determined by IFU. Silencing of Rab14 by siRNA also decreased bacteria multiplication and infectivity. By electron microscopy, aberrant bacteria were observed in cells overexpressing the cytosolic negative Rab14 mutant. Our results showed that Rab14 facilitates the delivery of sphingolipids required for bacterial development and replication from the Golgi to chlamydial inclusions. Novel anti-chlamydial therapies could be developed based on the knowledge of how bacteria subvert host vesicular transport events through Rabs manipulation. PMID:21124879

  2. 402 nature genetics volume 32 november 2002 Genome sequence of the endocellular obligate symbiont

    E-print Network

    Aksoy, Serap

    such intracellular microbe for nutritional provision- ing and fecundity. As a result of co-evolution with hosts over nutrition and fecundity, have been retained. Unexpectedly, this oblig- ate's genome bears hallmarks of both. Many arthropods with restricted diets, such as vertebrate blood, plant juice or wood, rely on symbiotic

  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. The Olive Fly Endosymbiont, “Candidatus Erwinia dacicola,” Switches from an Intracellular Existence to an Extracellular Existence during Host Insect Development? †

    PubMed Central

    Estes, Anne M.; Hearn, David J.; Bronstein, Judith L.; Pierson, Elizabeth A.

    2009-01-01

    As polyphagous, holometabolous insects, tephritid fruit flies (Diptera: Tephritidae) provide a unique habitat for endosymbiotic bacteria, especially those microbes associated with the digestive system. Here we examine the endosymbiont of the olive fly [Bactrocera oleae (Rossi) (Diptera: Tephritidae)], a tephritid of great economic importance. “Candidatus Erwinia dacicola” was found in the digestive systems of all life stages of wild olive flies from the southwestern United States. PCR and microscopy demonstrated that “Ca. Erwinia dacicola” resided intracellularly in the gastric ceca of the larval midgut but extracellularly in the lumen of the foregut and ovipositor diverticulum of adult flies. “Ca. Erwinia dacicola” is one of the few nonpathogenic endosymbionts that transitions between intracellular and extracellular lifestyles during specific stages of the host's life cycle. Another unique feature of the olive fly endosymbiont is that unlike obligate endosymbionts of monophagous insects, “Ca. Erwinia dacicola” has a G+C nucleotide composition similar to those of closely related plant-pathogenic and free-living bacteria. These two characteristics of “Ca. Erwinia dacicola,” the ability to transition between intracellular and extracellular lifestyles and a G+C nucleotide composition similar to those of free-living relatives, may facilitate survival in a changing environment during the development of a polyphagous, holometabolous host. We propose that insect-bacterial symbioses should be classified based on the environment that the host provides to the endosymbiont (the endosymbiont environment). PMID:19767463

  5. 38 CFR 17.607 - Obligated service.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...AFFAIRS MEDICAL Va Health Professional Scholarship Program § 17.607 Obligated service...for which the participant received a scholarship award under these regulations...obligation. A participant who received a scholarship as a full-time student must be...

  6. 38 CFR 17.607 - Obligated service.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...AFFAIRS MEDICAL Va Health Professional Scholarship Program § 17.607 Obligated service...for which the participant received a scholarship award under these regulations...obligation. A participant who received a scholarship as a full-time student must be...

  7. 38 CFR 17.607 - Obligated service.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...AFFAIRS MEDICAL Va Health Professional Scholarship Program § 17.607 Obligated service...for which the participant received a scholarship award under these regulations...obligation. A participant who received a scholarship as a full-time student must be...

  8. 45 CFR 2400.65 - Teaching obligation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...obligation. 2400.65 Section 2400.65 Public Welfare Regulations Relating to Public Welfare (Continued) JAMES MADISON MEMORIAL FELLOWSHIP FOUNDATION FELLOWSHIP PROGRAM REQUIREMENTS Special Conditions § 2400.65 Teaching obligation....

  9. 45 CFR 2400.65 - Teaching obligation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...obligation. 2400.65 Section 2400.65 Public Welfare Regulations Relating to Public Welfare (Continued) JAMES MADISON MEMORIAL FELLOWSHIP FOUNDATION FELLOWSHIP PROGRAM REQUIREMENTS Special Conditions § 2400.65 Teaching obligation....

  10. 45 CFR 2400.65 - Teaching obligation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...obligation. 2400.65 Section 2400.65 Public Welfare Regulations Relating to Public Welfare (Continued) JAMES MADISON MEMORIAL FELLOWSHIP FOUNDATION FELLOWSHIP PROGRAM REQUIREMENTS Special Conditions § 2400.65 Teaching obligation....

  11. 45 CFR 2400.65 - Teaching obligation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...obligation. 2400.65 Section 2400.65 Public Welfare Regulations Relating to Public Welfare (Continued) JAMES MADISON MEMORIAL FELLOWSHIP FOUNDATION FELLOWSHIP PROGRAM REQUIREMENTS Special Conditions § 2400.65 Teaching obligation....

  12. 45 CFR 2400.65 - Teaching obligation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...obligation. 2400.65 Section 2400.65 Public Welfare Regulations Relating to Public Welfare (Continued) JAMES MADISON MEMORIAL FELLOWSHIP FOUNDATION FELLOWSHIP PROGRAM REQUIREMENTS Special Conditions § 2400.65 Teaching obligation....

  13. 34 CFR 108.5 - Compliance obligations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...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...

  14. 38 CFR 17.607 - Obligated service.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...AFFAIRS MEDICAL Va Health Professional Scholarship Program § 17.607 Obligated service...for which the participant received a scholarship award under these regulations...obligation. A participant who received a scholarship as a full-time student must be...

  15. 34 CFR 108.5 - Compliance obligations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...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...

  16. 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...

  17. Can't take the heat: high temperature depletes bacterial endosymbionts of ants.

    PubMed

    Fan, Yongliang; Wernegreen, Jennifer J

    2013-10-01

    Members of the ant tribe Camponotini have coevolved with Blochmannia, an obligate intracellular bacterial mutualist. This endosymbiont lives within host bacteriocyte cells that line the ant midgut, undergoes maternal transmission from host queens to offspring, and contributes to host nutrition via nitrogen recycling and nutrient biosynthesis. While elevated temperature has been shown to disrupt obligate bacterial mutualists of some insects, its impact on the ant-Blochmannia partnership is less clear. Here, we test the effect of heat on the density of Blochmannia in two related Camponotus species in the lab. Transcriptionally active Blochmannia were quantified using RT-qPCR as the ratio of Blochmannia 16S rRNA to ant host elongation factor 1-? transcripts. Our results showed that 4 weeks of heat treatment depleted active Blochmannia by >99 % in minor workers and unmated queens. However, complete elimination of Blochmannia transcripts rarely occurred, even after 16 weeks of heat treatment. Possible mechanisms of observed thermal sensitivity may include extreme AT-richness and related features of Blochmannia genomes, as well as host stress responses. Broadly, the observed depletion of an essential microbial mutualist in heat-treated ants is analogous to the loss of zooanthellae during coral bleaching. While the ecological relevance of Blochmannia's thermal sensitivity is uncertain, our results argue that symbiont dynamics should be part of models predicting how ants and other animals will respond and adapt to a warming climate. PMID:23872930

  18. Can’t Take the Heat: High Temperature Depletes Bacterial Endosymbionts of Ants

    PubMed Central

    Fan, Yongliang; Wernegreen, Jennifer J.

    2014-01-01

    Members of the ant tribe Camponotini have coevolved with Blochmannia, an obligate intracellular bacterial mutualist. This endosymbiont lives within host bacteriocyte cells that line the ant midgut, undergoes maternal transmission from host queens to offspring, and contributes to host nutrition via nitrogen recycling and nutrient biosynthesis. While elevated temperature has been shown to disrupt obligate bacterial mutualists of some insects, its impact on the ant-Blochmannia partnership is less clear. Here, we test the effect of heat on the density of Blochmannia in two related Camponotus species in the lab. Transcriptionally active Blochmannia were quantified using RT-qPCR as the ratio of Blochmannia 16S rRNA to ant host elongation factor 1-? transcripts. Our results showed that 4 weeks of heat treatment depleted active Blochmannia by >99 % in minor workers and unmated queens. However, complete elimination of Blochmannia transcripts rarely occurred, even after 16 weeks of heat treatment. Possible mechanisms of observed thermal sensitivity may include extreme AT-richness and related features of Blochmannia genomes, as well as host stress responses. Broadly, the observed depletion of an essential microbial mutualist in heat-treated ants is analogous to the loss of zooanthellae during coral bleaching. While the ecological relevance of Blochmannia’s thermal sensitivity is uncertain, our results argue that symbiont dynamics should be part of models predicting how ants and other animals will respond and adapt to a warming climate. PMID:23872930

  19. Ehrlichia chaffeensis Exploits Host SUMOylation Pathways To Mediate Effector-Host Interactions and Promote Intracellular Survival

    PubMed Central

    Dunphy, Paige Selvy; Luo, Tian

    2014-01-01

    Ehrlichia chaffeensis is an obligately intracellular Gram-negative bacterium that selectively infects mononuclear phagocytes. We recently reported that E. chaffeensis utilizes a type 1 secretion (T1S) system to export tandem repeat protein (TRP) effectors and demonstrated that these effectors interact with a functionally diverse array of host proteins. By way of these interactions, TRP effectors modulate host cell functions; however, the molecular basis of these interactions and their roles in ehrlichial pathobiology are not well defined. In this study, we describe the first bacterial protein posttranslational modification (PTM) by the small ubiquitin-like modifier (SUMO). The E. chaffeensis T1S effector TRP120 is conjugated to SUMO at a carboxy-terminal canonical consensus SUMO conjugation motif in vitro and in human cells. In human cells, TRP120 was selectively conjugated with SUMO2/3 isoforms. Disruption of TRP120 SUMOylation perturbed interactions with known host proteins, through predicted SUMO interaction motif-dependent and -independent mechanisms. E. chaffeensis infection did not result in dramatic changes in the global host SUMOylated protein profile, but a robust colocalization of predominately SUMO1 with ehrlichial inclusions was observed. Inhibiting the SUMO pathway with a small-molecule inhibitor had a significant impact on E. chaffeensis replication and recruitment of the TRP120-interacting protein polycomb group ring finger protein 5 (PCGF5) to the inclusion, indicating that the SUMO pathway is critical for intracellular survival. This study reveals the novel exploitation of the SUMO pathway by Ehrlichia, which facilitates effector-eukaryote interactions necessary to usurp the host and create a permissive intracellular niche. PMID:25047847

  20. Bacterial DNA Sifted from the Trichoplax adhaerens (Animalia: Placozoa) Genome Project Reveals a Putative Rickettsial Endosymbiont

    PubMed Central

    Driscoll, Timothy; Gillespie, Joseph J.; Nordberg, Eric K.; Azad, Abdu F.; Sobral, Bruno W.

    2013-01-01

    Eukaryotic genome sequencing projects often yield bacterial DNA sequences, data typically considered as microbial contamination. However, these sequences may also indicate either symbiont genes or lateral gene transfer (LGT) to host genomes. These bacterial sequences can provide clues about eukaryote–microbe interactions. Here, we used the genome of the primitive animal Trichoplax adhaerens (Metazoa: Placozoa), which is known to harbor an uncharacterized Gram-negative endosymbiont, to search for the presence of bacterial DNA sequences. Bioinformatic and phylogenomic analyses of extracted data from the genome assembly (181 bacterial coding sequences [CDS]) and trace read archive (16S rDNA) revealed a dominant proteobacterial profile strongly skewed to Rickettsiales (Alphaproteobacteria) genomes. By way of phylogenetic analysis of 16S rDNA and 113 proteins conserved across proteobacterial genomes, as well as identification of 27 rickettsial signature genes, we propose a Rickettsiales endosymbiont of T. adhaerens (RETA). The majority (93%) of the identified bacterial CDS belongs to small scaffolds containing prokaryotic-like genes; however, 12 CDS were identified on large scaffolds comprised of eukaryotic-like genes, suggesting that T. adhaerens might have recently acquired bacterial genes. These putative LGTs may coincide with the placozoan’s aquatic niche and symbiosis with RETA. This work underscores the rich, and relatively untapped, resource of eukaryotic genome projects for harboring data pertinent to host–microbial interactions. The nature of unknown (or poorly characterized) bacterial species may only emerge via analysis of host genome sequencing projects, particularly if these species are resistant to cell culturing, as are many obligate intracellular microbes. Our work provides methodological insight for such an approach. PMID:23475938

  1. Real-time molecular monitoring of chemical environment in obligate anaerobes during oxygen adaptive response

    PubMed Central

    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.

    2009-01-01

    Determining the transient chemical properties of the intracellular environment can elucidate the paths through which a biological system adapts to changes in its environment, for example, the mechanisms that 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 bond structures in their cellular water. We observed a sequence of well orchestrated 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. PMID:19541631

  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. 38 CFR 17.607 - Obligated service.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...AFFAIRS MEDICAL Va Health Professional Scholarship Program § 17.607 Obligated service...school year or part thereof for which a scholarship was awarded, but for no less than 2...obligation. A participant who receives a scholarship as a full-time student must be...

  4. Collectivizing rescue obligations in bioethics.

    PubMed

    Garrett, Jeremy R

    2015-02-01

    Bioethicists invoke a duty to rescue in a wide range of cases. Indeed, arguably, there exists an entire medical paradigm whereby vast numbers of medical encounters are treated as rescue cases. The intuitive power of the rescue paradigm is considerable, but much of this power stems from the problematic way that rescue cases are conceptualized-namely, as random, unanticipated, unavoidable, interpersonal events for which context is irrelevant and beneficence is the paramount value. In this article, I critique the basic assumptions of the rescue paradigm, reframe the ethical landscape in which rescue obligations are understood, and defend the necessity and value of a wider social and institutional view. Along the way, I move back and forth between ethical theory and a concrete case where the duty to rescue has been problematically applied: the purported duty to regularly return incidental findings and individual research results in genomic and genetic research. PMID:25674948

  5. The Intracellular Bacteria Chlamydia Hijack Peroxisomes and Utilize Their Enzymatic Capacity to Produce Bacteria-Specific Phospholipids

    PubMed Central

    Boncompain, Gaelle; Müller, Constanze; Meas-Yedid, Vannary; Schmitt-Kopplin, Philippe; Lazarow, Paul B.; Subtil, Agathe

    2014-01-01

    Chlamydia trachomatis is an obligate intracellular pathogen responsible for loss of eyesight through trachoma and for millions of cases annually of sexually transmitted diseases. The bacteria develop within a membrane-bounded inclusion. They lack enzymes for several biosynthetic pathways, including those to make some phospholipids, and exploit their host to compensate. Three-dimensional fluorescence microscopy demonstrates that small organelles of the host, peroxisomes, are translocated into the Chlamydia inclusion and are found adjacent to the bacteria. In cells deficient for peroxisome biogenesis the bacteria are able to multiply and give rise to infectious progeny, demonstrating that peroxisomes are not essential for bacterial development in vitro. Mass spectrometry-based lipidomics reveal the presence in C. trachomatis of plasmalogens, ether phospholipids whose synthesis begins in peroxisomes and have never been described in aerobic bacteria before. Some of the bacterial plasmalogens are novel structures containing bacteria-specific odd-chain fatty acids; they are not made in uninfected cells nor in peroxisome-deficient cells. Their biosynthesis is thus accomplished by the metabolic collaboration of peroxisomes and bacteria. PMID:24465954

  6. 24 CFR 891.755 - Obligations of the family.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Obligations of the family. 891.755 Section 891.755...Projects for the Nonelderly Handicapped Families and Individuals-Section 162 Assistance § 891.755 Obligations of the family. The obligations of the...

  7. 29 CFR 5.31 - Meeting wage determination obligations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    29 Labor 1 2014-07-01 2013-07-01 true Meeting wage determination obligations...determination may discharge his minimum wage obligations for the payment...subcontractor may discharge his minimum wage obligations for the...

  8. 46 CFR 298.30 - Nature and content of Obligations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...46 Shipping 8 2010-10-01 2010-10-01 false Nature and content of Obligations. 298.30 Section 298.30...ASSISTANCE OBLIGATION GUARANTEES Documentation § 298.30 Nature and content of Obligations. (a) Single page....

  9. 46 CFR 298.30 - Nature and content of Obligations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...46 Shipping 8 2012-10-01 2012-10-01 false Nature and content of Obligations. 298.30 Section 298.30...ASSISTANCE OBLIGATION GUARANTEES Documentation § 298.30 Nature and content of Obligations. (a) Single page....

  10. 46 CFR 298.30 - Nature and content of Obligations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...46 Shipping 8 2011-10-01 2011-10-01 false Nature and content of Obligations. 298.30 Section 298.30...ASSISTANCE OBLIGATION GUARANTEES Documentation § 298.30 Nature and content of Obligations. (a) Single page....

  11. 46 CFR 298.30 - Nature and content of Obligations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...46 Shipping 8 2014-10-01 2014-10-01 false Nature and content of Obligations. 298.30 Section 298.30...ASSISTANCE OBLIGATION GUARANTEES Documentation § 298.30 Nature and content of Obligations. (a) Single page....

  12. 46 CFR 298.30 - Nature and content of Obligations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...46 Shipping 8 2013-10-01 2013-10-01 false Nature and content of Obligations. 298.30 Section 298.30...ASSISTANCE OBLIGATION GUARANTEES Documentation § 298.30 Nature and content of Obligations. (a) Single page....

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 47 CFR 64.1300 - Payphone compensation obligation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Payphone compensation obligation. 64.1300... FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER... § 64.1300 Payphone compensation obligation. (a...by contract. (c) The compensation obligation set forth...

  19. Phylogenetic divergence between the obligate luminous symbionts of flashlight fishes demonstrates specificity of bacteria to host genera.

    PubMed

    Hendry, Tory A; Dunlap, Paul V

    2014-08-01

    The luminous bacterial symbionts of anomalopid flashlight fishes, which appear to be obligately dependent on their hosts for growth, share several evolutionary patterns with unrelated obligate bacteria. However, only one flashlight fish symbiont species has been characterized in detail, and it is therefore not known if the bacteria from other anomalopid species are highly divergent (a pattern common to obligate symbionts). Unlike most obligate symbionts, the bacteria symbiotic with anomalopids are extracellular and spend time outside their hosts in the environment, from which they are thought to colonize new host generations. Environmental acquisition might decrease the likelihood of bacterial divergence between host species. We used phylogenetic analysis to determine the relatedness of symbionts from different anomalopid host species. The symbionts of hosts in the genus Photoblepharon were resolved as a new species, for which we propose the name 'Candidatus?Photodesmus blepharus'. Furthermore, different genera of anomalopids were found to harbour different species of bacteria, even when the hosts overlapped in geographic range. This finding suggests that the divergence between bacterial species is not the result of geographic isolation. The specificity of symbionts to host genera is consistent with obligate dependence on the host and has implications for symbiont transmission. PMID:24992531

  20. Detection of a novel intracellular microbiome hosted in arbuscular mycorrhizal fungi

    PubMed Central

    Desirò, Alessandro; Salvioli, Alessandra; Ngonkeu, Eddy L; Mondo, Stephen J; Epis, Sara; Faccio, Antonella; Kaech, Andres; Pawlowska, Teresa E; Bonfante, Paola

    2014-01-01

    Arbuscular mycorrhizal fungi (AMF) are important members of the plant microbiome. They are obligate biotrophs that colonize the roots of most land plants and enhance host nutrient acquisition. Many AMF themselves harbor endobacteria in their hyphae and spores. Two types of endobacteria are known in Glomeromycota: rod-shaped Gram-negative Candidatus Glomeribacter gigasporarum, CaGg, limited in distribution to members of the Gigasporaceae family, and coccoid Mollicutes-related endobacteria, Mre, widely distributed across different lineages of AMF. The goal of the present study is to investigate the patterns of distribution and coexistence of the two endosymbionts, CaGg and Mre, in spore samples of several strains of Gigaspora margarita. Based on previous observations, we hypothesized that some AMF could host populations of both endobacteria. To test this hypothesis, we performed an extensive investigation of both endosymbionts in G. margarita spores sampled from Cameroonian soils as well as in the Japanese G. margarita MAFF520054 isolate using different approaches (molecular phylotyping, electron microscopy, fluorescence in situ hybridization and quantitative real-time PCR). We found that a single AMF host can harbour both types of endobacteria, with Mre population being more abundant, variable and prone to recombination than the CaGg one. Both endosymbionts seem to retain their genetic and lifestyle peculiarities regardless of whether they colonize the host alone or together. These findings show for the first time that fungi support an intracellular bacterial microbiome, in which distinct types of endobacteria coexist in a single cell. PMID:24008325

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

    PubMed Central

    Huang, Jin; Lesser, Cammie F.; Lory, Stephen

    2008-01-01

    Bacterial virulence determinants can be identified, according to the molecular Koch’s postulates1, 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 factors. Here we demonstrate an approach to studying potential virulence factors of genetically intractable organisms, such as Chlamydia. Heterologous expression of Chlamydia pneumoniae CopN in yeast and mammalian cells resulted in a cell cycle arrest, presumably owing to alterations in the microtubule cytoskeleton. A screen of a small molecule library identified two compounds that alleviated CopN-induced growth inhibition in yeast. These compounds interfered with C. pneumoniae replication in mammalian cells, presumably by ‘knocking out’ CopN function, revealing an essential role of CopN in the support of C. pneumoniae growth during infection. This work demonstrates the role of a specific chlamydial protein in virulence. The chemical biology approach described here can be used to identify virulence factors, and the reverse chemical genetic strategy can result in the identification of lead compounds for the development of novel therapeutics. PMID:18830244

  2. Intracellular Invasion of Orientia tsutsugamushi Activates Inflammasome in ASC-Dependent Manner

    PubMed Central

    Koo, Jung-Eun; Hong, Hye-Jin; Dearth, Andrea; Kobayashi, Koichi S.; Koh, Young-Sang

    2012-01-01

    Orientia tsutsugamushi, a causative agent of scrub typhus, is an obligate intracellular bacterium, which escapes from the endo/phagosome and replicates in the host cytoplasm. O. tsutsugamushi infection induces production of pro-inflammatory mediators including interleukin-1? (IL-1?), which is secreted mainly from macrophages upon cytosolic stimuli by activating cysteine protease caspase-1 within a complex called the inflammasome, and is a key player in initiating and maintaining the inflammatory response. However, the mechanism for IL-1? maturation upon O. tsutsugamushi infection has not been identified. In this study, we show that IL-1 receptor signaling is required for efficient host protection from O. tsutsugamushi infection. Live Orientia, but not heat- or UV-inactivated Orientia, activates the inflammasome through active bacterial uptake and endo/phagosomal maturation. Furthermore, Orientia-stimulated secretion of IL-1? and activation of caspase-1 are ASC- and caspase-1- dependent since IL-1? production was impaired in Asc- and caspase-1-deficient macrophages but not in Nlrp3-, Nlrc4- and Aim2-deficient macrophages. Therefore, live O. tsutsugamushi triggers ASC inflammasome activation leading to IL-1? production, which is a critical innate immune response for effective host defense. PMID:22723924

  3. 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.

  4. Intracellular Parasitism of Chlamydiae: Specific Infectivity of Chlamydiaphage Chp2 in Chlamydophila abortus?

    PubMed Central

    Skilton, R. J.; Cutcliffe, L. T.; Pickett, M. A.; Lambden, P. R.; Fane, B. A.; Clarke, I. N.

    2007-01-01

    The obligate intracellular nature of chlamydiae presents challenges to the characterization of its phages, which are potential tools for a genetic transfer system. An assay for phage infectivity is described, and the infectious properties of phage Chp2 were determined. PMID:17468245

  5. Intracellular functions of galectins

    Microsoft Academic Search

    Fu-Tong Liu; Ronald J Patterson; John L Wang

    2002-01-01

    Many galectin family members are detected primarily intracellularly in most of the systems studied, although certain members can be found both inside and outside of cells. Specific functions that are consistent with their intracellular localization have now been documented for some of the galectins. Galectin-1 and -3 have been identified as redundant pre-mRNA splicing factors. Galectin-3, -7, and -12 have

  6. Image analyzing method to evaluate in situ bioluminescence from an obligate anaerobe cultivated under various dissolved oxygen concentrations.

    PubMed

    Ninomiya, Kazuaki; Yamada, Ryuji; Matsumoto, Masami; Fukiya, Satoru; Katayama, Takane; Ogino, Chiaki; Shimizu, Nobuaki

    2013-02-01

    An image analyzing method was developed to evaluate in situ bioluminescence expression, without exposing the culture sample to the ambient oxygen atmosphere. Using this method, we investigated the effect of dissolved oxygen concentration on bioluminescence from an obligate anaerobe Bifidobacterium longum expressing bacterial luciferase which catalyzes an oxygen-requiring bioluminescent reaction. PMID:23040354

  7. 7 CFR 989.37 - Obligation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN IN CALIFORNIA Order Regulating Handling Raisin Administrative Committee § 989.37 Obligation....

  8. 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 ...

  9. 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)...

  10. 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)...

  11. 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)...

  12. 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)...

  13. 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)...

  14. 19 CFR 10.805 - Importer obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Bahrain Free Trade Agreement Import Requirements § 10.805 Importer obligations. (a) General. An importer who...

  15. 38 CFR 17.632 - Obligated service.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...17.632 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS MEDICAL Visual Impairment and Orientation and Mobility Professional Scholarship Program § 17.632 Obligated service. (a) General provision....

  16. 19 CFR 10.585 - Importer obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. Dominican Republic-Central America-United States Free Trade Agreement Import Requirements § 10.585 Importer obligations. (a) General. An...

  17. 19 CFR 10.1005 - 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-Korea Free Trade Agreement Import Requirements § 10.1005 Importer obligations. (a) General. An importer who...

  18. 19 CFR 10.1005 - 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-Korea Free Trade Agreement Import Requirements § 10.1005 Importer obligations. (a) General. An importer who...

  19. 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 the...

  20. 5 CFR 352.908 - Agency obligation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...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 the...

  1. 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 the...

  2. 5 CFR 352.908 - Agency obligation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...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 the...

  3. 5 CFR 352.908 - Agency obligation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...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 the...

  4. 19 CFR 10.512 - Importer obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Singapore Free Trade Agreement Import Requirements § 10.512 Importer obligations. (a) General. An...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 19 CFR 10.765 - Importer obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Morocco Free Trade Agreement Import Requirements § 10.765 Importer obligations. (a) General . An importer who...

  11. 19 CFR 10.412 - Importer obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Chile Free Trade Agreement Import Requirements § 10.412 Importer obligations. (a) General. An importer...

  12. 19 CFR 10.412 - 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-Chile Free Trade Agreement Import Requirements § 10.412 Importer obligations. (a) General. An importer...

  13. 19 CFR 10.412 - 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-Chile Free Trade Agreement Import Requirements § 10.412 Importer obligations. (a) General. An importer...

  14. 19 CFR 10.412 - Importer obligations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Chile Free Trade Agreement Import Requirements § 10.412 Importer obligations. (a) General. An importer...

  15. 19 CFR 10.412 - 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-Chile Free Trade Agreement Import Requirements § 10.412 Importer obligations. (a) General. An importer...

  16. Expression of CXCR1 (Interleukin-8 Receptor) in Murine Macrophages After Staphylococcus aureus Infection and its Possible Implication on Intracellular Survival Correlating with Cytokines and Bacterial Anti-Oxidant Enzymes.

    PubMed

    Bishayi, Biswadev; Bandyopadhyay, Debasish; Majhi, Arnab; Adhikary, Rana

    2015-04-01

    Interaction with the live Staphylococcus aureus promotes secretion of interleukin-8 (IL-8), although the expressions of functional CXCR1 (IL-8RA) in murine macrophages have not been identified. Expression of CXCR1 was induced in S. aureus-infected macrophages, whereas, CXCR1 was undetectable in control macrophages. CXCR1 blocking significantly reduced the phagocytosis of S. aureus and TNF-?, IL-6, IL-1?, IFN-?, IL-12, and IL-8 production and increased release of MIP-2 and soluble TNF-R1. Increased bacterial catalase and decreased superoxide dismutase (SOD) activities by S. aureus with concomitant decrease in hydrogen peroxide (H2O2), superoxide anion, and nitric oxide (NO) release were observed in case of prior CXCR1 blocking. In the presence of cytochalasin D, S. aureus-mediated induction of IL-8 was inhibited concomitant with decreased bacterial count suggesting that internalization of S. aureus was necessary for induction of IL-8. Shedding of TNF-R1 due to CXCR1 blocking after S. aureus inoculation was critical for neutralization of TNF-? signaling and arrests the inflammation. PMID:25129059

  17. Filial Obligations in Post-Divorce Stepfamilies

    Microsoft Academic Search

    Marilyn Coleman; Lawrence H. Ganong; Jason D. Hans; Elizabeth A. Sharp; Tanja C. Rothrauff

    2005-01-01

    The purpose of this study was to assess adult children's obligations to assist older divorced parents and stepparents. Attitudes of 1,009 randomly selected participants were elicited using a vignette that portrayed a situation adult (step)children experience in post-divorce families. Findings suggest that, (a) adult children are obligated to help their divorced parents, (b) kinship is not a sufficient reason for

  18. Authentic Springs of Action and Obligation

    Microsoft Academic Search

    Ishtiyaque Haji

    2008-01-01

    What is the connection between action that is caused by inauthentic antecedent springs of action, such as surreptitiously\\u000a engineered-in desires and beliefs, and moral obligation? If, for example, an agent performs an action that derives from such\\u000a antecedent springs can it be that the agent is not obligated to perform this action owing to the inauthenticity of its causal antecedents?

  19. 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

  20. Macrophage defense mechanisms against intracellular bacteria

    PubMed Central

    Weiss, Günter; Schaible, Ulrich E

    2015-01-01

    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

  1. Species-specific engagement of human nucleotide oligomerization domain 2 (NOD)2 and Toll-like receptor (TLR) signalling upon intracellular bacterial infection: role of Crohn's associated NOD2 gene variants.

    PubMed

    Salem, M; Seidelin, J B; Eickhardt, S; Alhede, M; Rogler, G; Nielsen, O H

    2015-03-01

    Recognition of bacterial peptidoglycan-derived muramyl-dipeptide (MDP) by nucleotide oligomerization domain 2 (NOD2) induces crucial innate immune responses. Most bacteria carry the N-acetylated form of MDP (A-MDP) in their cell membranes, whereas N-glycolyl MDP (G-MDP) is typical for mycobacteria. Experimental murine studies have reported G-MDP to have a greater NOD2-stimulating capacity than A-MDP. As NOD2 polymorphisms are associated with Crohn's disease (CD), a link has been suggested between mycobacterial infections and CD. Thus, the aim was to investigate if NOD2 responses are dependent upon type of MDP and further to determine the role of NOD2 gene variants for the bacterial recognition in CD. The response pattern to A-MDP, G-MDP, Mycobacterium segmatis (expressing mainly G-MDP) and M.?segmatis?namH (expressing A-MDP), Listeria monocytogenes (LM) (an A-MDP-containing bacteria) and M. avium paratuberculosis (MAP) (a G-MDP-containing bacteria associated with CD) was investigated in human peripheral blood mononuclear cells (PBMCs). A-MDP and M.?segmatis?namH induced significantly higher tumour necrosis factor (TNF)-? protein levels in healthy wild-type NOD2?PBMCs compared with G-MDP and M.?segmatis. NOD2 mutations resulted in a low tumour necrosis factor (TNF)-? protein secretion following stimulation with LM. Contrary to this, TNF-? levels were unchanged upon MAP stimulation regardless of NOD2 genotype and MAP solely activated NOD2- and Toll-like receptor (TLRs)-pathway with an enhanced production of interleukin (IL)-1? and IL-10. In conclusion, the results indicate that CD-associated NOD2 deficiencies might affect the response towards a broader array of commensal and pathogenic bacteria expressing A-MDP, whereas they attenuate the role of mycobacteria in the pathogenesis of CD. PMID:25335775

  2. Chloride Channels of Intracellular Membranes

    PubMed Central

    Edwards, John C.; Kahl, Christina R.

    2010-01-01

    Proteins implicated as intracellular chloride channels include the intracellular ClC proteins, the bestrophins, the cystic fibrosis transmembrane conductance regulator, the CLICs, and the recently described Golgi pH regulator. This paper examines current hypotheses regarding roles of intracellular chloride channels and reviews the evidence supporting a role in intracellular chloride transport for each of these proteins. PMID:20100480

  3. Bacterial thermotaxis by speed modulation

    NASA Astrophysics Data System (ADS)

    Demir, Mahmut

    One of the most important factors that affects bacterial migration and is sensitive to thermal changes is the bacterial swimming speed controlled by the rotation of the flagellar motors. In the natural habitats of bacteria, gradients often extend over relatively long distances such that their steepness is too small for bacteria to detect. We studied the bacterial behavior in such thermal gradients and found that they migrate along shallow thermal gradients due to a change in their swimming speed resulting from the effect of temperature on the intracellular pH. When nutrients are scarce the bacteria's intracellular pH and consequently the swimming speed decreases with increasing temperature, which causes them to drift towards the warm end of the gradient. However, when serine is added to the medium at concentrations >300microM, the intracellular pH increases causing the swimming speed to increase continuously with increasing temperature, and the bacteria to drift towards the cold end of the gradient. This directional migration is not a result of bacterial thermotaxis in the classical sense, because the steepness of the gradients is below the sensing threshold of bacteria. Nevertheless, our results show that the directional switch requires the presence of the bacterial sensing receptors which seem to be involved in regulating the intracellular pH. Additionally, it is also important to understand how thermal fluctuations and rate of thermal changes experienced by bacteria during their excursion in natural environments affect their run speed. To this end we have studied the dynamics of the bacterial flagellar motor's speed in response to thermal fluctuations by tethering bacteria to a glass surface through their flagella. Our results show that under heavy load the response of the motor to fast linear thermal changes is instantaneous. However, when subjected to thermal fluctuations with varying frequency, they exhibit a resonant response to specific frequencies reflecting the complex internal dynamics of the motor.

  4. Intracellular mechanisms of aminoglycoside-induced cytotoxicity

    PubMed Central

    Karasawa, Takatoshi; Steyger, Peter S.

    2013-01-01

    Since introduction into clinical practice over 60 years ago, aminoglycoside antibiotics remain important drugs in the treatment of bacterial infections, cystic fibrosis and tuberculosis. However, the ototoxic and nephrotoxic properties of these drugs are still a major clinical problem. Recent advances in molecular biology and biochemistry have begun to uncover the intracellular actions of aminoglycosides that lead to cytotoxicity. In this review, we discuss intracellular binding targets of aminoglycosides, highlighting specific aminoglycoside-binding proteins (HSP73, calreticulin and CLIMP-63) and their potential for triggering caspases and Bcl-2 signalling cascades that are involved in aminoglycoside-induced cytotoxicity. We also discuss potential strategies to reduce aminoglycoside cytotoxicity, which are necessary for greater bactericidal efficacy during aminoglycoside pharmacotherapy. PMID:21799993

  5. 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...

  6. 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

  7. Sterile-?- and Armadillo Motif-Containing Protein Inhibits the TRIF-Dependent Downregulation of Signal Regulatory Protein ? To Interfere with Intracellular Bacterial Elimination in Burkholderia pseudomallei-Infected Mouse Macrophages

    PubMed Central

    Baral, Pankaj

    2013-01-01

    Burkholderia pseudomallei, the causative agent of melioidosis, evades macrophage killing by suppressing the TRIF-dependent pathway, leading to inhibition of inducible nitric oxide synthase (iNOS) expression. We previously demonstrated that virulent wild-type B. pseudomallei inhibits the TRIF-dependent pathway by upregulating sterile-?- and armadillo motif-containing protein (SARM) and by inhibiting downregulation of signal regulatory protein ? (SIRP?); both molecules are negative regulators of Toll-like receptor signaling. In contrast, the less virulent lipopolysaccharide (LPS) mutant of B. pseudomallei is unable to exhibit these features and is susceptible to macrophage killing. However, the functional relationship of these two negative regulators in the evasion of macrophage defense has not been elucidated. We demonstrated here that SIRP? downregulation was observed after inhibition of SARM expression by small interfering RNA in wild-type-infected macrophages, indicating that SIRP? downregulation is regulated by SARM. Furthermore, this downregulation requires activation of the TRIF signaling pathway, as we observed abrogation of SIRP? downregulation as well as restricted bacterial growth in LPS mutant-infected TRIF-depleted macrophages. Although inhibition of SARM expression is correlated to SIRP? downregulation and iNOS upregulation in gamma interferon-activated wild-type-infected macrophages, these phenomena appear to bypass the TRIF-dependent pathway. Similar to live bacteria, the wild-type LPS is able to upregulate SARM and to prevent SIRP? downregulation, implying that the LPS of B. pseudomallei may play a crucial role in regulating the expression of these two negative regulators. Altogether, our findings show a previously unrecognized role of B. pseudomallei-induced SARM in inhibiting SIRP? downregulation-mediated iNOS upregulation, facilitating the ability of the bacterium to multiply in macrophages. PMID:23836818

  8. Understanding how commensal obligate anaerobic bacteria regulate immune functions in the large intestine.

    PubMed

    Maier, Eva; Anderson, Rachel C; Roy, Nicole C

    2015-01-01

    The human gastrointestinal tract is colonised by trillions of commensal bacteria, most of which are obligate anaerobes residing in the large intestine. Appropriate bacterial colonisation is generally known to be critical for human health. In particular, the development and function of the immune system depends on microbial colonisation, and a regulated cross-talk between commensal bacteria, intestinal epithelial cells and immune cells is required to maintain mucosal immune homeostasis. This homeostasis is disturbed in various inflammatory disorders, such as inflammatory bowel diseases. Several in vitro and in vivo studies indicate a role for Faecalibacterium prausnitzii, Bacteroides thetaiotaomicron, Bacteroides fragilis, Akkermansia muciniphila and segmented filamentous bacteria in maintaining intestinal immune homeostasis. These obligate anaerobes are abundant in the healthy intestine but reduced in several inflammatory diseases, suggesting an association with protective effects on human health. However, knowledge of the mechanisms underlying the effects of obligate anaerobic intestinal bacteria remains limited, in part due to the difficulty of co-culturing obligate anaerobes together with oxygen-requiring human epithelial cells. By using novel dual-environment co-culture models, it will be possible to investigate the effects of the unstudied majority of intestinal microorganisms on the human epithelia. This knowledge will provide opportunities for improving human health and reducing the risk of inflammatory diseases. PMID:25545102

  9. Understanding How Commensal Obligate Anaerobic Bacteria Regulate Immune Functions in the Large Intestine

    PubMed Central

    Maier, Eva; Anderson, Rachel C.; Roy, Nicole C.

    2014-01-01

    The human gastrointestinal tract is colonised by trillions of commensal bacteria, most of which are obligate anaerobes residing in the large intestine. Appropriate bacterial colonisation is generally known to be critical for human health. In particular, the development and function of the immune system depends on microbial colonisation, and a regulated cross-talk between commensal bacteria, intestinal epithelial cells and immune cells is required to maintain mucosal immune homeostasis. This homeostasis is disturbed in various inflammatory disorders, such as inflammatory bowel diseases. Several in vitro and in vivo studies indicate a role for Faecalibacterium prausnitzii, Bacteroides thetaiotaomicron, Bacteroides fragilis, Akkermansia muciniphila and segmented filamentous bacteria in maintaining intestinal immune homeostasis. These obligate anaerobes are abundant in the healthy intestine but reduced in several inflammatory diseases, suggesting an association with protective effects on human health. However, knowledge of the mechanisms underlying the effects of obligate anaerobic intestinal bacteria remains limited, in part due to the difficulty of co-culturing obligate anaerobes together with oxygen-requiring human epithelial cells. By using novel dual-environment co-culture models, it will be possible to investigate the effects of the unstudied majority of intestinal microorganisms on the human epithelia. This knowledge will provide opportunities for improving human health and reducing the risk of inflammatory diseases. PMID:25545102

  10. Bacterial Sialidase

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Data shows that elevated sialidase in bacterial vaginosis patients correlates to premature births in women. Bacterial sialidase also plays a significant role in the unusual colonization of Pseudomonas aeruginosa in cystic fibrosis patients. Crystals of Salmonella sialidase have been reproduced and are used for studying the inhibitor-enzyme complexes. These inhibitors may also be used to inhibit a trans-sialidase of Trypanosome cruzi, a very similar enzyme to bacterial sialidase, therefore preventing T. cruzi infection, the causitive agent of Chagas' disease. The Center for Macromolecular Crystallography suggests that inhibitors of bacterial sialidases can be used as prophylactic drugs to prevent bacterial infections in these critical cases.

  11. 40 CFR 1043.30 - General obligations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  12. 40 CFR 1043.30 - General obligations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  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. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 22 CFR 221.15 - Fiscal Agent obligations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...false Fiscal Agent obligations. 221.15 Section 221.15 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEE STANDARD TERMS AND CONDITIONS The Guarantee § 221.15 Fiscal Agent obligations. Failure of the...

  20. 22 CFR 221.15 - Fiscal Agent obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...false Fiscal Agent obligations. 221.15 Section 221.15 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEE STANDARD TERMS AND CONDITIONS The Guarantee § 221.15 Fiscal Agent obligations. Failure of the...

  1. 22 CFR 221.15 - Fiscal Agent obligations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...false Fiscal Agent obligations. 221.15 Section 221.15 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEE STANDARD TERMS AND CONDITIONS The Guarantee § 221.15 Fiscal Agent obligations. Failure of the...

  2. 22 CFR 221.15 - Fiscal Agent obligations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...false Fiscal Agent obligations. 221.15 Section 221.15 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEE STANDARD TERMS AND CONDITIONS The Guarantee § 221.15 Fiscal Agent obligations. Failure of the...

  3. 22 CFR 221.15 - Fiscal Agent obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...false Fiscal Agent obligations. 221.15 Section 221.15 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEE STANDARD TERMS AND CONDITIONS The Guarantee § 221.15 Fiscal Agent obligations. Failure of the...

  4. Divine voluntarism: moral obligation supervenes on God's antecedent will

    E-print Network

    Nam, Mi Young

    2004-11-15

    undesirable implications, e.g., that moral obligation is arbitrary and that God's goodness is trivial. Also, while it avoids these undesirable implications, divine voluntarism must not imply that God is, in some way, restricted by moral obligation which exists...

  5. 47 CFR 24.247 - Triggering a reimbursement obligation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...reimbursement obligation. 24.247 Section 24.247 Telecommunication FEDERAL COMMUNICATIONS...the 1850-1990 Mhz Band § 24.247 Triggering a reimbursement obligation...1996, as amended at 62 FR 12757, Mar. 18, 1997; 69 FR 67836,...

  6. 47 CFR 24.247 - Triggering a reimbursement obligation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...reimbursement obligation. 24.247 Section 24.247 Telecommunication FEDERAL COMMUNICATIONS...the 1850-1990 Mhz Band § 24.247 Triggering a reimbursement obligation...1996, as amended at 62 FR 12757, Mar. 18, 1997; 69 FR 67836,...

  7. 47 CFR 24.247 - Triggering a reimbursement obligation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...reimbursement obligation. 24.247 Section 24.247 Telecommunication FEDERAL COMMUNICATIONS...the 1850-1990 Mhz Band § 24.247 Triggering a reimbursement obligation...1996, as amended at 62 FR 12757, Mar. 18, 1997; 69 FR 67836,...

  8. 47 CFR 24.247 - Triggering a reimbursement obligation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...reimbursement obligation. 24.247 Section 24.247 Telecommunication FEDERAL COMMUNICATIONS...the 1850-1990 Mhz Band § 24.247 Triggering a reimbursement obligation...1996, as amended at 62 FR 12757, Mar. 18, 1997; 69 FR 67836,...

  9. 47 CFR 24.247 - Triggering a reimbursement obligation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...reimbursement obligation. 24.247 Section 24.247 Telecommunication FEDERAL COMMUNICATIONS...the 1850-1990 Mhz Band § 24.247 Triggering a reimbursement obligation...1996, as amended at 62 FR 12757, Mar. 18, 1997; 69 FR 67836,...

  10. 29 CFR 1984.102 - Obligations and prohibited acts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Obligations and prohibited acts. 1984.102 Section 1984.102 Labor Regulations Relating to Labor (Continued...Investigations, Findings and Preliminary Orders § 1984.102 Obligations and prohibited acts....

  11. 29 CFR 1984.102 - Obligations and prohibited acts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Obligations and prohibited acts. 1984.102 Section 1984.102 Labor Regulations Relating to Labor (Continued...Investigations, Findings and Preliminary Orders § 1984.102 Obligations and prohibited acts....

  12. 38 CFR 17.608 - Deferment of obligated service.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...obligated service. (a) Request for deferment. A participant receiving a degree from a school of medicine, osteopathy, dentistry, optometry, or podiatry, may request deferment of obligated service to complete an approved program of advanced...

  13. 38 CFR 17.608 - Deferment of obligated service.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...obligated service. (a) Request for deferment. A participant receiving a degree from a school of medicine, osteopathy, dentistry, optometry, or podiatry, may request deferment of obligated service to complete an approved program of advanced...

  14. 38 CFR 17.608 - Deferment of obligated service.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...obligated service. (a) Request for deferment. A participant receiving a degree from a school of medicine, osteopathy, dentistry, optometry, or podiatry, may request deferment of obligated service to complete an approved program of advanced...

  15. 38 CFR 17.608 - Deferment of obligated service.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...obligated service. (a) Request for deferment. A participant receiving a degree from a school of medicine, osteopathy, dentistry, optometry, or podiatry, may request deferment of obligated service to complete an approved program of advanced...

  16. 38 CFR 17.608 - Deferment of obligated service.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...obligated service. (a) Request for deferment. A participant receiving a degree from a school of medicine, osteopathy, dentistry, optometry, or podiatry, may request deferment of obligated service to complete an approved program of advanced...

  17. 18 CFR 35.18 - Asset retirement obligations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...components related to the asset retirement obligations...components related to asset retirement obligations...depreciation and accumulated deferred income taxes, may not be reflected...base costs related to asset retirement costs in...

  18. 18 CFR 154.315 - Asset retirement obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...components related to the asset retirement obligations...components related to asset retirement obligations...depreciation and accumulated deferred income taxes, may not be reflected...base costs related to asset retirement...

  19. 18 CFR 154.315 - Asset retirement obligations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...components related to the asset retirement obligations...components related to asset retirement obligations...depreciation and accumulated deferred income taxes, may not be reflected...base costs related to asset retirement...

  20. 18 CFR 35.18 - Asset retirement obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...components related to the asset retirement obligations...components related to asset retirement obligations...depreciation and accumulated deferred income taxes, may not be reflected...base costs related to asset retirement costs in...

  1. 29 CFR 4043.20 - Post-Event filing obligation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 2010-07-01 false Post-Event filing obligation. 4043.20 ...AND CERTAIN OTHER NOTIFICATION REQUIREMENTS Post-Event Notice of Reportable Events § 4043.20 Post-Event filing obligation. The plan...

  2. 47 CFR 51.703 - Reciprocal compensation obligation of LECs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Reciprocal compensation obligation of LECs. 51... FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER...INTERCONNECTION Reciprocal Compensation for Transport and Termination... § 51.703 Reciprocal compensation obligation of LECs....

  3. Discovery of Putative Small Non-Coding RNAs from the Obligate Intracellular Bacterium Wolbachia pipientis

    PubMed Central

    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

  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. cPLA2 Regulates the Expression of Type I Interferons and Intracellular Immunity to Chlamydia trachomatis*

    PubMed Central

    Vignola, Mark J.; Kashatus, David F.; Taylor, Gregory A.; Counter, Christopher M.; Valdivia, Raphael H.

    2010-01-01

    Infection with the obligate bacterial intracellular pathogen Chlamydia trachomatis leads to the sustained activation of the small GTPase RAS and many of its downstream signaling components. In particular, the mitogen-activated protein kinase ERK and the calcium-dependent phospholipase cPLA2 are activated and are important for the onset of inflammatory responses. In this study we tested if activation of ERK and cPLA2 occurred as a result of RAS signaling during infection and determined the relative contribution of these signaling components to chlamydial replication and survival. We provide genetic and pharmacological evidence that during infection RAS, ERK, and, to a lesser extent, cPLA2 activation are uncoupled, suggesting that Chlamydia activates individual components of this signaling pathway in a non-canonical manner. In human cell lines, inhibition of ERK or cPLA2 signaling did not adversely impact C. trachomatis replication. In contrast, in murine cells, inhibition of ERK and cPLA2 played a significant protective role against C. trachomatis. We determined that cPLA2-deficient murine cells are permissive for C. trachomatis replication because of their impaired expression of ? interferon and the induction of immunity-related GTPases (IRG) important for the containment of intracellular pathogens. Furthermore, the MAPK p38 was primarily responsible for cPLA2 activation in Chlamydia-infected cells and IRG expression. Overall, these findings define a previously unrecognized role for cPLA2 in the induction of cell autonomous cellular immunity to Chlamydia and highlight the many non-canonical signaling pathways engaged during infection. PMID:20452986

  6. Dominant obligate anaerobes revealed in lower respiratory tract infection in horses by 16S rRNA gene sequencing.

    PubMed

    Kinoshita, Yuta; Niwa, Hidekazu; Katayama, Yoshinari; Hariu, Kazuhisa

    2014-04-01

    Obligate anaerobes are important etiological agents in pneumonia or pleuropneumonia in horses, because they are isolated more commonly from ill horses that have died or been euthanized than from those that survive. We performed bacterial identification and antimicrobial susceptibility testing for obligate anaerobes to establish effective antimicrobial therapy. We used 16S rRNA gene sequencing to identify 58 obligate anaerobes and compared the results with those from a phenotypic identification kit. The identification results of 16S rRNA gene sequencing were more reliable than those of the commercial kit. We concluded that genera Bacteroides and Prevotella-especially B. fragilis and P. heparinolytica-are dominant anaerobes in lower respiratory tract infection in horses; these organisms were susceptible to metronidazole, imipenem and clindamycin. PMID:24366152

  7. 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)

  8. Abnormalities in the handling of intracellular bacteria in Crohn's disease.

    PubMed

    Lapaquette, Pierre; Darfeuille-Michaud, Arlette

    2010-09-01

    Ileal lesions in Crohn's disease (CD) patients are colonized by pathogenic adherent-invasive Escherichia coli (AIEC) able to invade and to replicate within intestinal epithelial cells. Recent advances have highlighted the importance of the innate immune system and the critical relationship between the gut flora and the intestinal mucosa. Several combinations of genetic predisposing factors to CD have been described, with the most significant replicable associations including genes for intracellular receptor of bacterial cell walls (NOD2/CARD15), and for bacterial clearance and antigen processing through autophagy (ATG16L1 and IRGM). We recently reported that in IRGM and ATG16L1 deficient cells, intracellular AIEC LF82 bacteria have enhanced replication and that autophagy deficiency surprisingly did not interfere with the ability of intracellular bacteria to survive and/or replicate for any other E. coli strains tested, including nonpathogenic, environmental, commensal, or pathogenic strains involved in gastroenteritis. As autophagy is an innate defense mechanism acting as a cell-autonomous system for elimination of intracellular pathogens, these findings lead weight to the notion that intracellular bacteria including AIEC might play a role in CD pathogenesis. PMID:20616747

  9. 7 CFR 1488.12 - Coverage of bank obligations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Coverage of bank obligations. 1488.12 Section 1488...Export Credit Sales Program (GSM-5) Bank Obligations and Repayment § 1488.12 Coverage of bank obligations. (a) U.S. banks and...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 40 CFR 80.1107 - How is the Renewable Volume Obligation calculated?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false How is the Renewable Volume Obligation calculated? 80.1107 Section...Standard § 80.1107 How is the Renewable Volume Obligation calculated? (a) The Renewable Volume Obligation for an obligated party is...

  16. 40 CFR 80.1107 - How is the Renewable Volume Obligation calculated?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false How is the Renewable Volume Obligation calculated? 80.1107 Section...Standard § 80.1107 How is the Renewable Volume Obligation calculated? (a) The Renewable Volume Obligation for an obligated party is...

  17. 40 CFR 80.1107 - How is the Renewable Volume Obligation calculated?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false How is the Renewable Volume Obligation calculated? 80.1107 Section...Standard § 80.1107 How is the Renewable Volume Obligation calculated? (a) The Renewable Volume Obligation for an obligated party is...

  18. 40 CFR 80.1107 - How is the Renewable Volume Obligation calculated?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false How is the Renewable Volume Obligation calculated? 80.1107 Section...Standard § 80.1107 How is the Renewable Volume Obligation calculated? (a) The Renewable Volume Obligation for an obligated party is...

  19. 40 CFR 80.1107 - How is the Renewable Volume Obligation calculated?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false How is the Renewable Volume Obligation calculated? 80.1107 Section...Standard § 80.1107 How is the Renewable Volume Obligation calculated? (a) The Renewable Volume Obligation for an obligated party is...

  20. Bacterial vaginosis

    Microsoft Academic Search

    Jane R. Schwebke

    2000-01-01

    Bacterial vaginosis, the most prevalent cause of vaginal discharge in the United States, is characterized microbiologically\\u000a by a shift in the vagina away from a lactobacillus-predominant flora and toward a predominantly anaerobic milieu. The cause\\u000a of bacterial vaginosis is unknown, but the epidemiology of the syndrome suggests that it is sexually associated. Bacterial\\u000a vaginosis has been associated with various complications,

  1. ELECTRICAL STIMULATION RESEARCH TECHNIQUES Intracellular Stimulation

    E-print Network

    Byrne, John H.

    ELECTRICAL STIMULATION RESEARCH TECHNIQUES Chapter 2 Intracellular Stimulation John H. Byrne Introduction . . . . . . . . . 37 II. Intracellular Stimulation and Recording with Separate Electrodes 38 Ill. A Simple Circuit for Intracellular Stimulation with Two Electrodes 42 IV. Intracellular Stimulation

  2. Bacterial Gut Symbionts Contribute to Seed Digestion in an Omnivorous Beetle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Obligate bacterial symbionts alter the diets of host animals in numerous ways, but the ecological roles of facultative bacterial residents that consistently colonize insect guts remain unclear. Carabid beetles are a common group of beneficial insects appreciated for their ability to consume insect p...

  3. Phenotypic Signatures Arising from Unbalanced Bacterial Growth

    PubMed Central

    Tan, Cheemeng; Smith, Robert Phillip; Tsai, Ming-Chi; Schwartz, Russell; You, Lingchong

    2014-01-01

    Fluctuations in the growth rate of a bacterial culture during unbalanced growth are generally considered undesirable in quantitative studies of bacterial physiology. Under well-controlled experimental conditions, however, these fluctuations are not random but instead reflect the interplay between intra-cellular networks underlying bacterial growth and the growth environment. Therefore, these fluctuations could be considered quantitative phenotypes of the bacteria under a specific growth condition. Here, we present a method to identify “phenotypic signatures” by time-frequency analysis of unbalanced growth curves measured with high temporal resolution. The signatures are then applied to differentiate amongst different bacterial strains or the same strain under different growth conditions, and to identify the essential architecture of the gene network underlying the observed growth dynamics. Our method has implications for both basic understanding of bacterial physiology and for the classification of bacterial strains. PMID:25101949

  4. Nanovehicular Intracellular Delivery Systems

    PubMed Central

    PROKOP, ALES; DAVIDSON, JEFFREY M.

    2013-01-01

    This article provides an overview of principles and barriers relevant to intracellular drug and gene transport, accumulation and retention (collectively called as drug delivery) by means of nanovehicles (NV). The aim is to deliver a cargo to a particular intracellular site, if possible, to exert a local action. Some of the principles discussed in this article apply to noncolloidal drugs that are not permeable to the plasma membrane or to the blood–brain barrier. NV are defined as a wide range of nanosized particles leading to colloidal objects which are capable of entering cells and tissues and delivering a cargo intracelullarly. Different localization and targeting means are discussed. Limited discussion on pharmacokinetics and pharmacodynamics is also presented. NVs are contrasted to micro-delivery and current nanotechnologies which are already in commercial use. Newer developments in NV technologies are outlined and future applications are stressed. We also briefly review the existing modeling tools and approaches to quantitatively describe the behavior of targeted NV within the vascular and tumor compartments, an area of particular importance. While we list “elementary” phenomena related to different level of complexity of delivery to cancer, we also stress importance of multi-scale modeling and bottom-up systems biology approach. PMID:18200527

  5. Cationic Antimicrobial Peptide LL-37 Is Effective against both Extra- and Intracellular Staphylococcus aureus

    PubMed Central

    Noore, Jabeen; Noore, Adly

    2013-01-01

    The increasing resistance of bacteria to conventional antibiotics and the challenges posed by intracellular bacteria, which may be responsible for chronic and recurrent infections, have driven the need for advanced antimicrobial drugs for effective elimination of both extra- and intracellular pathogens. The purpose of this study was to determine the killing efficacy of cationic antimicrobial peptide LL-37 compared to conventional antibiotics against extra- and intracellular Staphylococcus aureus. Bacterial killing assays and an infection model of osteoblasts and S. aureus were studied to determine the bacterial killing efficacy of LL-37 and conventional antibiotics against extra- and intracellular S. aureus. We found that LL-37 was effective in killing extracellular S. aureus at nanomolar concentrations, while lactoferricin B was effective at micromolar concentrations and doxycycline and cefazolin at millimolar concentrations. LL-37 was surprisingly more effective in killing the clinical strain than in killing an ATCC strain of S. aureus. Moreover, LL-37 was superior to conventional antibiotics in eliminating intracellular S. aureus. The kinetic studies further revealed that LL-37 was fast in eliminating both extra- and intracellular S. aureus. Therefore, LL-37 was shown to be very potent and prompt in eliminating both extra- and intracellular S. aureus and was more effective in killing extra- and intracellular S. aureus than commonly used conventional antibiotics. LL-37 could potentially be used to treat chronic and recurrent infections due to its effectiveness in eliminating not only extracellular but also intracellular pathogens. PMID:23274662

  6. INTRA-CELLULAR STAPHYLOCOCCUS AUREUS ALONE CAUSES INFECTION IN VIVO#

    PubMed Central

    Hamza, Therwa; Dietz, Matthew; Pham, Danh; Clovis, Nina; Danley, Suzanne; Li, Bingyun

    2013-01-01

    Chronic and recurrent bone infections occur frequently but have not been explained. Staphylococcus aureus (S. aureus) is often found among chronic and recurrent infections and may be responsible for such infections. One possible reason is that S. aureus can internalize and survive within host cells and by doing so, S. aureus can evade both host defense mechanisms and most conventional antibiotic treatments. In this study, we hypothesized that intra-cellular S. aureus could induce infections in vivo. Osteoblasts were infected with S. aureus and, after eliminating extra-cellular S. aureus, inoculated into an open fracture rat model. Bacterial cultures and radiographic observations at post-operative day 21 confirmed local bone infections in animals inoculated with intra-cellular S. aureus within osteoblasts alone. We present direct in vivo evidence that intra-cellular S. aureus could be sufficient to induce bone infection in animals; we found that intra-cellular S. aureus inoculation of as low as 102 colony forming units could induce severe bone infections. Our data may suggest that intra-cellular S. aureus can “hide” in host cells during symptom-free periods and, under certain conditions, they may escape and lead to infection recurrence. Intra-cellular S. aureus therefore could play an important role in the pathogenesis of S. aureus infections, especially those chronic and recurrent infections in which disease episodes may be separated by weeks, months, or even years. PMID:23832687

  7. Bacterial vaginosis

    Microsoft Academic Search

    Jeff Wang

    2000-01-01

    Bacterial vaginosis is the most common cause of vaginitis, affecting over 3 million women in the United States annually. Depopulation of lactobacilli from the normal vaginal flora and overgrowth of Gardnerella vaginalis and other anaerobic species are the presumed etiology. To date, no scientific evidence shows that bacterial vaginosis is a sexually transmitted disease. Malodorous vaginal discharge is the most

  8. Ecophysiological Characteristics of Obligate Methanotrophic Bacteria and Methane Oxidation In Situ

    NASA Technical Reports Server (NTRS)

    King, Gary M.

    1993-01-01

    Most of the obligate methane-oxidizing bacteria (MOB) described to date are neutrophilic mesophiles that grow optimally in dilute media. Kinetic analyses generally indicate that bacterial methane uptake occurs by transport systems with a K(sub m) greater than l micronM. These and other properties of MOB are inconsistent with characteristics of methane oxidation in situ. The inconsistencies indicate a need for greater attention to the ecophysiological characteristics of isolates and the design of enrichment and isolation schemes which emphasize ecologically relevant parameters (e.g., low temperature, limited and diverse substrate availability, low water potential).

  9. Genome Reduction and Co-evolution between the Primary and Secondary Bacterial Symbionts of Psyllids

    PubMed Central

    Sloan, Daniel B.; Moran, Nancy A.

    2012-01-01

    Genome reduction in obligately intracellular bacteria is one of the most well-established patterns in the field of molecular evolution. In the extreme, many sap-feeding insects harbor nutritional symbionts with genomes that are so reduced that it is not clear how they perform basic cellular functions. For example, the primary symbiont of psyllids (Carsonella) maintains one of the smallest and most AT-rich bacterial genomes ever identified and has surprisingly lost many genes that are thought to be essential for its role in provisioning its host with amino acids. However, our understanding of this extreme case of genome reduction is limited, as genomic data for Carsonella are available from only a single host species, and little is known about the functional role of “secondary” bacterial symbionts in psyllids. To address these limitations, we analyzed complete Carsonella genomes from pairs of congeneric hosts in three divergent genera within the Psyllidae (Ctenarytaina, Heteropsylla, and Pachypsylla) as well as complete secondary symbiont genomes from two of these host species (Ctenarytaina eucalypti and Heteropsylla cubana). Although the Carsonella genomes are generally conserved in size, structure, and GC content and exhibit genome-wide signatures of purifying selection, we found that gene loss has remained active since the divergence of the host species and had a particularly large impact on the amino acid biosynthesis pathways that define the symbiotic role of Carsonella. In some cases, the presence of additional bacterial symbionts may compensate for gene loss in Carsonella, as functional gene content indicates a high degree of metabolic complementarity between co-occurring symbionts. The genomes of the secondary symbionts also show signatures of long-term evolution as vertically transmitted, intracellular bacteria, including more extensive genome reduction than typically observed in facultative symbionts. Therefore, a history of co-evolution with secondary bacterial symbionts can partially explain the ongoing genome reduction in Carsonella. However, the absence of these secondary symbionts in other host lineages indicates that the relationships are dynamic and that other mechanisms, such as changes in host diet or functional coordination with the host genome, must also be at play. PMID:22821013

  10. Switching modes of chromosome dynamics in the bacterial cell cycle

    E-print Network

    Rudner, David

    COMMENTARY Switching modes of chromosome dynamics in the bacterial cell cycle Barbara E. Funnell1 no nucleus, and the chromosomal DNA occupies much of the intracellular space in a highly compacted protein­DNA structure called the nucleoid. The genomes of most bacterial species consist of one circular chromosome

  11. Glutathione activates virulence gene expression of an intracellular pathogen.

    PubMed

    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

  12. Explicit hypoxia targeting with tumor suppression by creating an “obligate” anaerobic Salmonella Typhimurium strain

    PubMed Central

    Yu, Bin; Yang, Mei; Shi, Lei; Yao, Yandan; Jiang, Qinqin; Li, Xuefei; Tang, Lei-Han; Zheng, Bo-Jian; Yuen, Kwok-Yung; Smith, David K.; Song, Erwei; Huang, Jian-Dong

    2012-01-01

    Using bacteria as therapeutic agents against solid tumors is emerging as an area of great potential in the treatment of cancer. Obligate and facultative anaerobic bacteria have been shown to infiltrate the hypoxic regions of solid tumors, thereby reducing their growth rate or causing regression. However, a major challenge for bacterial therapy of cancer with facultative anaerobes is avoiding damage to normal tissues. Consequently the virulence of bacteria must be adequately attenuated for therapeutic use. By placing an essential gene under a hypoxia conditioned promoter, Salmonella Typhimurium strain SL7207 was engineered to survive only in anaerobic conditions (strain YB1) without otherwise affecting its functions. In breast tumor bearing nude mice, YB1 grew within the tumor, retarding its growth, while being rapidly eliminated from normal tissues. YB1 provides a safe bacterial vector for anti-tumor therapies without compromising the other functions or tumor fitness of the bacterium as attenuation methods normally do. PMID:22666539

  13. Bacterial Vaginosis

    MedlinePLUS

    ... Archive STDs Home Page Bacterial Vaginosis (BV) Chlamydia Gonorrhea Genital Herpes HIV/AIDS & STDs Human Papillomavirus (HPV) ... of getting other STDs, such as chlamydia and gonorrhea . These bacteria can sometimes cause pelvic inflammatory disease ( ...

  14. Experimental replacement of an obligate insect symbiont.

    PubMed

    Moran, Nancy A; Yun, Yueli

    2015-02-17

    Symbiosis, the close association of unrelated organisms, has been pivotal in biological diversification. In the obligate symbioses found in many insect hosts, organisms that were once independent are permanently and intimately associated, resulting in expanded ecological capabilities. The primary model for this kind of symbiosis is the association between the bacterium Buchnera and the pea aphid (Acyrthosiphon pisum). A longstanding obstacle to efforts to illuminate genetic changes underlying obligate symbioses has been the inability to experimentally disrupt and reconstitute symbiont-host partnerships. Our experiments show that Buchnera can be experimentally transferred between aphid matrilines and, furthermore, that Buchnera replacement has a massive effect on host fitness. Using a recipient pea aphid matriline containing Buchnera that are heat sensitive because of an allele eliminating the heat shock response of a small chaperone, we reduced native Buchnera through heat exposure and introduced a genetically distinct Buchnera from another matriline, achieving complete replacement and stable inheritance. This transfer disrupted 100 million years (?1 billion generations) of continuous maternal transmission of Buchnera in its host aphids. Furthermore, aphids with the Buchnera replacement enjoyed a dramatic increase in heat tolerance, directly demonstrating a strong effect of symbiont genotype on host ecology. PMID:25561531

  15. Silencing of Host Cell CYBB Gene Expression by the Nuclear Effector AnkA of the Intracellular Pathogen Anaplasma phagocytophilum

    Microsoft Academic Search

    Jose C. Garcia-Garcia; Kristen E. Rennoll-Bankert; Shaaretha Pelly; Aaron M. Milstone; J. Stephen Dumler

    2009-01-01

    Coevolution of intracellular bacterial pathogens and their host cells resulted in the appearance of effector molecules that when translocated into the host cell modulate its function, facilitating bacterial survival within the hostile host environment. Some of these effectors interact with host chromatin and other nuclear compo- nents. In this report, we show that the AnkA protein of Anaplasma phagocytophilum, which

  16. Francisella tularensis Harvests Nutrients Derived via ATG5-Independent Autophagy to Support Intracellular Growth

    PubMed Central

    Ziehr, Benjamin; Taft-Benz, Sharon; Moorman, Nathaniel; Kawula, Thomas

    2013-01-01

    Francisella tularensis is a highly virulent intracellular pathogen that invades and replicates within numerous host cell types including macrophages, hepatocytes and pneumocytes. By 24 hours post invasion, F. tularensis replicates up to 1000-fold in the cytoplasm of infected cells. To achieve such rapid intracellular proliferation, F. tularensis must scavenge large quantities of essential carbon and energy sources from the host cell while evading anti-microbial immune responses. We found that macroautophagy, a eukaryotic cell process that primarily degrades host cell proteins and organelles as well as intracellular pathogens, was induced in F. tularensis infected cells. F. tularensis not only survived macroautophagy, but optimal intracellular bacterial growth was found to require macroautophagy. Intracellular growth upon macroautophagy inhibition was rescued by supplying excess nonessential amino acids or pyruvate, demonstrating that autophagy derived nutrients provide carbon and energy sources that support F. tularensis proliferation. Furthermore, F. tularensis did not require canonical, ATG5-dependent autophagy pathway induction but instead induced an ATG5-independent autophagy pathway. ATG5-independent autophagy induction caused the degradation of cellular constituents resulting in the release of nutrients that the bacteria harvested to support bacterial replication. Canonical macroautophagy limits the growth of several different bacterial species. However, our data demonstrate that ATG5-independent macroautophagy may be beneficial to some cytoplasmic bacteria by supplying nutrients to support bacterial growth. PMID:23966861

  17. Relative entropy differences in bacterial chromosomes, plasmids, phages and genomic islands

    PubMed Central

    2012-01-01

    Background We sought to assess whether the concept of relative entropy (information capacity), could aid our understanding of the process of horizontal gene transfer in microbes. We analyzed the differences in information capacity between prokaryotic chromosomes, genomic islands (GI), phages, and plasmids. Relative entropy was estimated using the Kullback-Leibler measure. Results Relative entropy was highest in bacterial chromosomes and had the sequence chromosomes > GI > phage > plasmid. There was an association between relative entropy and AT content in chromosomes, phages, plasmids and GIs with the strongest association being in phages. Relative entropy was also found to be lower in the obligate intracellular Mycobacterium leprae than in the related M. tuberculosis when measured on a shared set of highly conserved genes. Conclusions We argue that relative entropy differences reflect how plasmids, phages and GIs interact with microbial host chromosomes and that all these biological entities are, or have been, subjected to different selective pressures. The rate at which amelioration of horizontally acquired DNA occurs within the chromosome is likely to account for the small differences between chromosomes and stably incorporated GIs compared to the transient or independent replicons such as phages and plasmids. PMID:22325062

  18. 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...

  19. Standard of care, institutional obligations, and distributive justice.

    PubMed

    MacKay, Douglas

    2015-05-01

    The problem of standard of care in clinical research concerns the level of treatment that investigators must provide to subjects in clinical trials. Commentators often formulate answers to this problem by appealing to two distinct types of obligations: professional obligations and natural duties. In this article, I investigate whether investigators also possess institutional obligations that are directly relevant to the problem of standard of care, that is, those obligations a person has because she occupies a particular institutional role. I examine two types of institutional contexts: (1) public research agencies - agencies or departments of states that fund or conduct clinical research in the public interest; and (2) private-for-profit corporations. I argue that investigators who are employed or have their research sponsored by the former have a distinctive institutional obligation to conduct their research in a way that is consistent with the state's duty of distributive justice to provide its citizens with access to basic health care, and its duty to aid citizens of lower income countries. By contrast, I argue that investigators who are employed or have their research sponsored by private-for-profit corporations do not possess this obligation nor any other institutional obligation that is directly relevant to the ethics of RCTs. My account of the institutional obligations of investigators aims to contribute to the development of a reasonable, distributive justice-based account of standard of care. PMID:24117682

  20. Cultural Generality of the Integration of Obligation and Other Motives

    ERIC Educational Resources Information Center

    Yang, Jen-Shou

    2012-01-01

    The purpose of the present study is twofold. One is to assess the cultural generality of the information integration rule for moral obligation. The other is to examine how people integrate moral obligation and self-interest. Two studies were implemented following the functional measurement methodology with Chinese samples. Study 1 replicated the…

  1. The Evolutionary Pathway to Obligate Scavenging in Gyps Vultures

    Microsoft Academic Search

    Brian J. Dermody; Colby J. Tanner; Andrew L. Jackson

    2011-01-01

    The evolutionary pathway to obligate scavenging in Gyps vultures remains unclear. We propose that communal roosting plays a central role in setting up the information transfer network critical for obligate scavengers in ephemeral environments and that the formation of a flotilla-like foraging group is a likely strategy for foraging Gyps vultures. Using a spatial, individual-based, optimisation model we find that

  2. 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…

  3. The Role Obligations of Students and Lecturers in Higher Education

    ERIC Educational Resources Information Center

    Regan, Julie-Anne

    2012-01-01

    The current discussion of consumerism in higher education focuses largely on what the providers are obliged to do for the consumers, against the background of rising tuition fees. This framework does not always sit comfortably with lecturers in the context of a learning and teaching relationship, as it appears to ignore the reciprocal obligations

  4. Energy Saving Obligations Cutting the Gordian Knot of leverage?

    E-print Network

    Paris-Sud XI, Université de

    leverage and additionality. KEYWORDS Energy Savings Obligation, Leverage, Financing hal-01016112,version1 and there was no requirement for member states to implement the instrument. This has now changed: The new Energy Efficiency1 Energy Saving Obligations Cutting the Gordian Knot of leverage? Pre-print version to appear

  5. In Defence of Associative Political Obligations: Part One

    Microsoft Academic Search

    John Horton

    2007-01-01

    Part One of this article seeks to defend the idea of associative political obligations against a number of criticisms that have been advanced opposing it.The purpose of this defence is not to demonstrate that the associative account is therefore the best explanation of political obligations, but only that the principal reasons which have been given for rejecting it are much

  6. Opportunism and competition in the non-fossil fuel obligation

    E-print Network

    Watson, Andrew

    Opportunism and competition in the non-fossil fuel obligation Paolo Agnolucci July 2005 Tyndall are the responsibility of the author(s) alone and not the Tyndall Centre. #12;Summary The Non-Fossil Fuel Order (NFFO Electricity; Renewable Policy, Non-Fossil Fuel Obligation; Moral Hazard; Post-contractual Opportunism #12

  7. Parental Beliefs about Nonresident Fathers' Obligations and Rights

    ERIC Educational Resources Information Center

    Lin, I-Fen; McLanahan, Sara S.

    2007-01-01

    We examine whether parents rely on principles of equity or equality in making judgments about nonresident fathers' obligations and rights. The data are taken from the first wave of the Fragile Families and Child Wellbeing Study. The analysis sample includes 4,304 new mothers and 3,414 new fathers. Results indicate that fathers perceive obligations

  8. Daughters’ Obligation to Care in the Context of Past Abuse

    Microsoft Academic Search

    Judith Wuest; Jean Malcolm; Marilyn Merritt-Gray

    2010-01-01

    Using theoretical sampling, we extended a previous grounded theory study of women's caring through interviews with 16 women currently giving care to parents who had abused them as children to more fully understand daughters’ obligation to care in the context of past abuse. Past relationship was characterized by emotional distance, “never being good enough,” degradation, control, and unpredictability. Obligation to

  9. Schooling properties of an obligate and a facultative fish species

    E-print Network

    Paris-Sud XI, Université de

    Schooling properties of an obligate and a facultative fish species M. SORIA* , P. FREON § and P, Nouvelle-Calédonie, France Schooling fish species are conventionally subdivided into obligate interactions, Schooling behaviour, Polarity, Pelagic fish Running headline: Schooling properties of two fish

  10. 7 CFR 1488.12 - Coverage of bank obligations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...Commodities From Private Stocks Under CCC Export Credit Sales Program (GSM-5) Bank Obligations and Repayment § 1488.12 Coverage...obligation. (j) Collection of accounts receivable purchased under GSM-5 will be effected through the issuance by CCC of sight...

  11. Bacterial Wilt

    Microsoft Academic Search

    Howard F. Schwartz; David H. Gent; Gary D. Franc; Robert M. Harveson

    Bacterial wilt is caused by the bacterium Curtobacterium flaccumfaciens subsp. flaccumfaciens. This pathogen grows throughout the water conducting tissues of the plant and impedes water movement, resulting in a wilt. Symptom development is favored by temperatures greater than 90°F. Infection is often caused by the planting of infected seed, but the pathogen may also survive in infested crop debris. Wilt

  12. Bacterial vaginosis

    Microsoft Academic Search

    Phillip Hay

    2010-01-01

    Bacterial vaginosis is the commonest cause of abnormal vaginal discharge in women of childbearing age, with a prevalence as high as 50% in some communities. The symptoms of discharge and offensive smell can cause considerable distress, although 50% of women are asymptomatic when diagnosed. Microbiologically the usually dominant lactobacillus flora is overwhelmed by an overgrowth of predominantly anaerobic organisms, accompanied

  13. Bacterial vaginosis

    Microsoft Academic Search

    Phillip Hay

    2005-01-01

    Bacterial vaginosis is a common cause of abnormal discharge in women of child-bearing age. It is present in 10–20% women in the UK, and may recur or regress spontaneously. It is not regarded as an STI because it can occur in virgin women, but it is more common in sexually active women. Other associations include smoking, partner change, having a

  14. 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....

  15. 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....

  16. 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....

  17. 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....

  18. 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....

  19. 42 CFR 1001.1501 - Default of health education loan or scholarship obligations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Default of health education loan or scholarship obligations. 1001.1501 Section... Default of health education loan or scholarship obligations. (a) Circumstance for...determines is in default on repayments of scholarship obligations or loans in...

  20. 42 CFR 1001.1501 - Default of health education loan or scholarship obligations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Default of health education loan or scholarship obligations. 1001.1501 Section... Default of health education loan or scholarship obligations. (a) Circumstance for...determines is in default on repayments of scholarship obligations or loans in...

  1. 42 CFR 1001.1501 - Default of health education loan or scholarship obligations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Default of health education loan or scholarship obligations. 1001.1501 Section... Default of health education loan or scholarship obligations. (a) Circumstance for...determines is in default on repayments of scholarship obligations or loans in...

  2. 42 CFR 1001.1501 - Default of health education loan or scholarship obligations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Default of health education loan or scholarship obligations. 1001.1501 Section... Default of health education loan or scholarship obligations. (a) Circumstance for...determines is in default on repayments of scholarship obligations or loans in...

  3. 42 CFR 1001.1501 - Default of health education loan or scholarship obligations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Default of health education loan or scholarship obligations. 1001.1501 Section... Default of health education loan or scholarship obligations. (a) Circumstance for...determines is in default on repayments of scholarship obligations or loans in...

  4. 31 CFR 225.9 - Return of Government obligations to obligor.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 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....

  5. 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....

  6. 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....

  7. 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....

  8. 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....

  9. 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

  10. A lack of parasitic reduction in the obligate parasitic green alga Helicosporidium.

    PubMed

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

    2014-05-01

    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

  11. 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

  12. Review of International Experience with Renewable Energy Obligation Support Mechanisms

    SciTech Connect

    Wiser, R.

    2005-06-01

    The main policy instruments currently used in the EU Member States to achieve the targets set for electricity produced from renewable energy sources are: (1) the quota obligation system; (2) the feed-in tariff system; and (3) the tendering system. The current study aims to review the experience gained with the quota obligation system. The report provides an overview of the regions where obligation systems have been implemented and contains a detailed evaluation of the performance of the obligation systems in the USA, the UK and in Sweden. The obligation systems in these countries have been evaluated based on the following criteria: Effectiveness; Market efficiency; Certainty for the renewable energy industry; Cost effectiveness; Stakeholder support for the obligation system; and Equity. The evaluation of international experiences with the obligation system gives rise to a mixed picture. Although an obligation in theory is effective and cost effective, it seems too early to conclude that the system delivers these promises in practice. On the one hand this is due to the limited period of implementation that makes it hard to distinguish between the direct effect of the system and some teething problems that will be solved in due time. On the other hand, the conclusion can be drawn that the obligation is a complex system, which will only function well if designed carefully. It does seem worthwhile, however, to continue monitoring the experiences with the obligation system abroad, because this will further reveal whether the system is indeed effective and cost effective in practice. In the longer term, e.g. beyond 2010, the introduction of an obligation system in the Netherlands could be considered. Finally, as the design of support schemes is being improved, it appears that the basic concepts of both the obligation system and the feed in system have been refined in such a way that the two systems are gradually converging. An important difference between the two systems however remains, namely that an obligation system relies more on market forces whereas the feed-in system is based on a greater involvement of the government.

  13. Autophagy and bacterial infectious diseases

    PubMed Central

    Yuk, Jae-Min; Yoshimori, Tamotsu

    2012-01-01

    Autophagy is a housekeeping process that maintains cellular homeostasis through recycling of nutrients and degradation of damaged or aged cytoplasmic constituents. Over the past several years, accumulating evidence has suggested that autophagy can function as an intracellular innate defense pathway in response to infection with a variety of bacteria and viruses. Autophagy plays a role as a specialized immunologic effector and regulates innate immunity to exert antimicrobial defense mechanisms. Numerous bacterial pathogens have developed the ability to invade host cells or to subvert host autophagy to establish a persistent infection. In this review, we have summarized the recent advances in our understanding of the interaction between antibacterial autophagy (xenophagy) and different bacterial pathogens. PMID:22257885

  14. 5 CFR 2422.34 - Rights and obligations during the pendency of representation proceedings.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...obligations during the pendency of representation proceedings. 2422.34...LABOR RELATIONS AUTHORITY REPRESENTATION PROCEEDINGS § 2422.34...obligations during the pendency of representation proceedings. (a)...

  15. 5 CFR 2422.34 - Rights and obligations during the pendency of representation proceedings.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...obligations during the pendency of representation proceedings. 2422.34...LABOR RELATIONS AUTHORITY REPRESENTATION PROCEEDINGS § 2422.34...obligations during the pendency of representation proceedings. (a)...

  16. 5 CFR 2422.34 - Rights and obligations during the pendency of representation proceedings.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...obligations during the pendency of representation proceedings. 2422.34...LABOR RELATIONS AUTHORITY REPRESENTATION PROCEEDINGS § 2422.34...obligations during the pendency of representation proceedings. (a)...

  17. 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

    -negative naturally obligate intracellular pathogen, is the etiological agent of Q fever, a zoonotic disease predominately associated with domestic livestock. The primary route of transmission occurs via inhalation of contaminated aerosols, resulting in an acute..., flu-like illness that is typically self-limiting and readily resolves without antibiotic treatment. However, in rare instances chronic Q fever can develop that results in chronic endocarditis or hepatitis (81). The highly infectious nature...

  18. Nutrient salvaging and metabolism by the intracellular pathogen Legionella pneumophila

    PubMed Central

    Fonseca, Maris V.; Swanson, Michele S.

    2014-01-01

    The Gram-negative bacterium Legionella pneumophila is ubiquitous in freshwater environments as a free-swimming organism, resident of biofilms, or parasite of protozoa. If the bacterium is aerosolized and inhaled by a susceptible human host, it can infect alveolar macrophages and cause a severe pneumonia known as Legionnaires' disease. A sophisticated cell differentiation program equips L. pneumophila to persist in both extracellular and intracellular niches. During its life cycle, L. pneumophila alternates between at least two distinct forms: a transmissive form equipped to infect host cells and evade lysosomal degradation, and a replicative form that multiplies within a phagosomal compartment that it has retooled to its advantage. The efficient changeover between transmissive and replicative states is fundamental to L. pneumophila's fitness as an intracellular pathogen. The transmission and replication programs of L. pneumophila are governed by a number of metabolic cues that signal whether conditions are favorable for replication or instead trigger escape from a spent host. Several lines of experimental evidence gathered over the past decade establish strong links between metabolism, cellular differentiation, and virulence of L. pneumophila. Herein, we focus on current knowledge of the metabolic components employed by intracellular L. pneumophila for cell differentiation, nutrient salvaging and utilization of host factors. Specifically, we highlight the metabolic cues that are coupled to bacterial differentiation, nutrient acquisition systems, and the strategies utilized by L. pneumophila to exploit host metabolites for intracellular replication. PMID:24575391

  19. Professionalism for Medicine: Opportunities and Obligations*

    PubMed Central

    Cruess, Sylvia R; Cruess, Richard L; Johnston, Sharon

    2004-01-01

    Physicians' dual roles-as healer and professional-are linked by codes of ethics governing behaviour and are empowered by science.Being part of a profession entails a societal contract. The profession is granted a monopoly over the use of a body of knowledge and the privilege of self-regulation and, in return, guarantees society professional competence, integrity and the provision of altruistic service.Societal attitudes to professionalism have changed from supportive to increasingly critical-with physicians being criticised for pursuing their own financial interests, and failing to self-regulate in a way that guarantees competence.Professional values are also threatened by many other factors. The most important are the changes in healthcare delivery in the developed world, with control shifting from the profession to the State and/or the corporate sector.For the ideal of professionalism to survive, physicians must understand it and its role in the social contract. They must meet the obligations necessary to sustain professionalism and ensure that healthcare systems support, rather than subvert, behaviour that is compatible with professionalism's values. PMID:15296199

  20. Asparagine assimilation is critical for intracellular replication and dissemination of Francisella.

    PubMed

    Gesbert, Gael; Ramond, Elodie; Rigard, Mélanie; Frapy, Eric; Dupuis, Marion; Dubail, Iharilalao; Barel, Monique; Henry, Thomas; Meibom, Karin; Charbit, Alain

    2014-03-01

    In order to develop a successful infectious cycle, intracellular bacterial pathogens must be able to adapt their metabolism to optimally utilize the nutrients available in the cellular compartments and tissues where they reside. Francisella tularensis, the agent of the zoonotic disease tularaemia, is a highly infectious bacterium for a large number of animal species. This bacterium replicates in its mammalian hosts mainly in the cytosol of infected macrophages. We report here the identification of a novel amino acid transporter of the major facilitator superfamily of secondary transporters that is required for bacterial intracellular multiplication and systemic dissemination. We show that inactivation of this transporter does not affect phagosomal escape but prevents multiplication in the cytosol of all cell types tested. Remarkably, the intracellular growth defect of the mutant was fully and specifically reversed by addition of asparagine or asparagine-containing dipeptides as well as by simultaneous addition of aspartic acid and ammonium. Importantly, bacterial virulence was also restored in vivo, in the mouse model, by asparagine supplementation. This work unravels thus, for the first time, the importance of asparagine for cytosolicmultiplication of Francisella. Amino acid transporters are likely to constitute underappreciated players in bacterial intracellular parasitism. PMID:24134488

  1. The Establishment of Intracellular Symbiosis in an Ancestor of Cockroaches and Termites

    Microsoft Academic Search

    Claudio Bandi; Massimo Sironi; Giuseppe Damiani; Lorenzo Magrassi; Christine A. Nalepa; Ugo Laudani; Luciano Sacchi

    1995-01-01

    All cockroaches examined so far have been found to harbour a bacterial endosymbiont in specialized cells of the fat body, whereas Mastotermes darwiniensis is the only termite currently known to harbour an intracellular symbiont. The localization and mode of transmission of these bacteria are surprisingly similar, but so far no data have been published on their phylogenetic relationships. To address

  2. The role of autophagy in the intracellular survival of Campylobacter concisus

    PubMed Central

    Burgos-Portugal, Jose A.; Mitchell, Hazel M.; Castaño-Rodríguez, Natalia; Kaakoush, Nadeem O.

    2014-01-01

    Campylobacter concisus is an emerging pathogen that has been associated with gastrointestinal diseases. Given the importance of autophagy for the elimination of intracellular bacteria and the subversion of this process by pathogenic bacteria, we investigated the role of autophagy in C. concisus intracellular survival. Gentamicin protection assays were employed to assess intracellular levels of C. concisus within Caco-2 cells, following autophagy induction and inhibition. To assess the interaction between C. concisus and autophagosomes, confocal microscopy, scanning electron microscopy, and transmission electron microscopy were employed. Expression levels of 84 genes involved in the autophagy process were measured using qPCR. Autophagy inhibition resulted in two- to four-fold increases in intracellular levels of C. concisus within Caco-2 cells, while autophagy induction resulted in a significant reduction in intracellular levels or bacterial clearance. C. concisus strains with low intracellular survival levels showed a dramatic increase in these levels upon autophagy inhibition. Confocal microscopy showed co-localization of the bacterium with autophagosomes, while transmission electron microscopy identified intracellular bacteria persisting within autophagic vesicles. Further, qPCR showed that following infection, 13 genes involved in the autophagy process were significantly regulated, and a further five showed borderline results, with an overall indication towards a dampening effect exerted by the bacterium on this process. Our data collectively indicates that while autophagy is important for the clearance of C. concisus, some strains may manipulate this process to benefit their intracellular survival. PMID:24918042

  3. Importance of branched-chain amino acid utilization in Francisella intracellular adaptation.

    PubMed

    Gesbert, Gael; Ramond, Elodie; Tros, Fabiola; Dairou, Julien; Frapy, Eric; Barel, Monique; Charbit, Alain

    2015-01-01

    Intracellular bacterial pathogens have adapted their metabolism to optimally utilize the nutrients available in infected host cells. We recently reported the identification of an asparagine transporter required specifically for cytosolic multiplication of Francisella. In the present work, we characterized a new member of the major super family (MSF) of transporters, involved in isoleucine uptake. We show that this transporter (here designated IleP) plays a critical role in intracellular metabolic adaptation of Francisella. Inactivation of IleP severely impaired intracellular F. tularensis subsp. novicida multiplication in all cell types tested and reduced bacterial virulence in the mouse model. To further establish the importance of the ileP gene in F. tularensis pathogenesis, we constructed a chromosomal deletion mutant of ileP (?FTL_1803) in the F. tularensis subsp. holarctica live vaccine strain (LVS). Inactivation of IleP in the F. tularensis LVS provoked comparable intracellular growth defects, confirming the critical role of this transporter in isoleucine uptake. The data presented establish, for the first time, the importance of isoleucine utilization for efficient phagosomal escape and cytosolic multiplication of Francisella and suggest that virulent F. tularensis subspecies have lost their branched-chain amino acid biosynthetic pathways and rely exclusively on dedicated uptake systems. This loss of function is likely to reflect an evolution toward a predominantly intracellular life style of the pathogen. Amino acid transporters should be thus considered major players in the adaptation of intracellular pathogens. PMID:25332124

  4. 22 CFR 230.07 - Fiscal Agent obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...false Fiscal Agent obligations. 230.07 Section 230.07 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEES ISSUED UNDER THE EMERGENCY WARTIME SUPPLEMENTAL APPROPRIATIONS ACT OF 2003, PUB. L. 108-11-STANDARD...

  5. 22 CFR 230.07 - Fiscal Agent obligations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...false Fiscal Agent obligations. 230.07 Section 230.07 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEES ISSUED UNDER THE EMERGENCY WARTIME SUPPLEMENTAL APPROPRIATIONS ACT OF 2003, PUB. L. 108-11-STANDARD...

  6. 22 CFR 230.07 - Fiscal Agent obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...false Fiscal Agent obligations. 230.07 Section 230.07 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEES ISSUED UNDER THE EMERGENCY WARTIME SUPPLEMENTAL APPROPRIATIONS ACT OF 2003, PUB. L. 108-11-STANDARD...

  7. 22 CFR 230.07 - Fiscal Agent obligations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...false Fiscal Agent obligations. 230.07 Section 230.07 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEES ISSUED UNDER THE EMERGENCY WARTIME SUPPLEMENTAL APPROPRIATIONS ACT OF 2003, PUB. L. 108-11-STANDARD...

  8. 22 CFR 230.07 - Fiscal Agent obligations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...false Fiscal Agent obligations. 230.07 Section 230.07 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEES ISSUED UNDER THE EMERGENCY WARTIME SUPPLEMENTAL APPROPRIATIONS ACT OF 2003, PUB. L. 108-11-STANDARD...

  9. 12 CFR 560.42 - State and local government obligations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...Indirect payments, such as through a special fund, may qualify as general obligations if a state or political subdivision with taxing authority has unconditionally agreed to provide funds to cover payments. (d) What is appropriate underwriting for...

  10. 12 CFR 160.42 - State and local government obligations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...Indirect payments, such as through a special fund, may qualify as general obligations if a state or political subdivision with taxing authority has unconditionally agreed to provide funds to cover payments. (d) For all securities, the...

  11. 12 CFR 160.42 - State and local government obligations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...Indirect payments, such as through a special fund, may qualify as general obligations if a state or political subdivision with taxing authority has unconditionally agreed to provide funds to cover payments. (d) For all securities, the...

  12. 7 CFR 760.507 - Obligations of a participant.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...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...

  13. 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...

  14. 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...

  15. 7 CFR 783.7 - Obligations of a participant.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...Regulations of the Department of Agriculture (Continued) FARM SERVICE AGENCY, DEPARTMENT OF AGRICULTURE SPECIAL PROGRAMS TREE ASSISTANCE PROGRAM § 783.7 Obligations of a participant. (a) Eligible orchardists must execute all required...

  16. 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...

  17. 7 CFR 1416.705 - Obligations of a participant.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS 2006 EMERGENCY AGRICULTURAL DISASTER ASSISTANCE PROGRAMS 2005 Hurricane Tree Assistance Program § 1416.705 Obligations of a participant. (a) Eligible producers must execute all required...

  18. 38 CFR 17.633 - Deferment of obligated service.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...17.633 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS MEDICAL Visual Impairment and Orientation and Mobility Professional Scholarship Program § 17.633 Deferment of obligated service. Deferment of...

  19. 32 CFR 220.9 - Rights and obligations of beneficiaries.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...party payer's plan. Such beneficiaries are also required to provide...might be applicable, a beneficiary has an obligation to provide...and this part, including identification of policy numbers, claim...2) Uniformed Services beneficiaries are required to...

  20. 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...

  1. 48 CFR 243.204-70-4 - Limitations on obligations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...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...

  2. 7 CFR 930.163 - Deferment of restricted obligation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...OF AGRICULTURE TART CHERRIES GROWN IN THE STATES OF MICHIGAN, NEW YORK, PENNSYLVANIA, OREGON, UTAH, WASHINGTON, AND WISCONSIN Administrative Rules and Regulations § 930.163 Deferment of restricted obligation. A handler...

  3. 18 CFR 367.2300 - Account 230, Asset retirement obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...SUBJECT TO THE PROVISIONS OF THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005, FEDERAL POWER ACT AND NATURAL GAS ACT Balance Sheet Chart of Accounts Other Noncurrent Liabilities § 367.2300 Account 230, Asset retirement obligations....

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 31 CFR 223.18 - Performance of agency obligations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Relating to Money and Finance (Continued) FISCAL SERVICE, DEPARTMENT OF THE TREASURY FINANCIAL MANAGEMENT SERVICE SURETY COMPANIES DOING BUSINESS WITH THE UNITED STATES § 223.18 Performance of agency obligations. (a)...

  10. 31 CFR 223.18 - Performance of agency obligations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Relating to Money and Finance (Continued) FISCAL SERVICE, DEPARTMENT OF THE TREASURY FINANCIAL MANAGEMENT SERVICE SURETY COMPANIES DOING BUSINESS WITH THE UNITED STATES § 223.18 Performance of agency obligations. (a)...

  11. 31 CFR 223.18 - Performance of agency obligations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Relating to Money and Finance (Continued) FISCAL SERVICE, DEPARTMENT OF THE TREASURY FINANCIAL MANAGEMENT SERVICE SURETY COMPANIES DOING BUSINESS WITH THE UNITED STATES § 223.18 Performance of agency obligations. (a)...

  12. 31 CFR 223.18 - Performance of agency obligations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Relating to Money and Finance (Continued) FISCAL SERVICE, DEPARTMENT OF THE TREASURY FINANCIAL MANAGEMENT SERVICE SURETY COMPANIES DOING BUSINESS WITH THE UNITED STATES § 223.18 Performance of agency obligations. (a)...

  13. 32 CFR 220.9 - Rights and obligations of beneficiaries.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...PARTY PAYERS OF REASONABLE CHARGES FOR HEALTHCARE SERVICES § 220.9 Rights and obligations...be required. (b) Availability of healthcare services unaffected. The availability of healthcare services in any facility of the...

  14. 32 CFR 220.9 - Rights and obligations of beneficiaries.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...PARTY PAYERS OF REASONABLE CHARGES FOR HEALTHCARE SERVICES § 220.9 Rights and obligations...be required. (b) Availability of healthcare services unaffected. The availability of healthcare services in any facility of the...

  15. 32 CFR 220.9 - Rights and obligations of beneficiaries.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...PARTY PAYERS OF REASONABLE CHARGES FOR HEALTHCARE SERVICES § 220.9 Rights and obligations...be required. (b) Availability of healthcare services unaffected. The availability of healthcare services in any facility of the...

  16. 32 CFR 220.9 - Rights and obligations of beneficiaries.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...PARTY PAYERS OF REASONABLE CHARGES FOR HEALTHCARE SERVICES § 220.9 Rights and obligations...be required. (b) Availability of healthcare services unaffected. The availability of healthcare services in any facility of the...

  17. Intense Transpositional Activity of Insertion Sequences in an Ancient Obligate Endosymbiont

    PubMed Central

    Pichon, Samuel; Ling, Alison; Pérez, Philippe; Delaunay, Carine; Vavre, Fabrice; Bouchon, Didier; Grève, Pierre

    2008-01-01

    The streamlined genomes of ancient obligate endosymbionts generally lack transposable elements, such as insertion sequences (IS). Yet, the genome of Wolbachia, one of the most abundant bacterial endosymbionts on Earth, is littered with IS. Such a paradox raises the question as to why there are so many ISs in the genome of this ancient endosymbiont. To address this question, we investigated IS transpositional activity in the unculturable Wolbachia by tracking the evolutionary dynamics and history of ISWpi1 elements. We show that 1) ISWpi1 is widespread in Wolbachia, being present in at least 55% of the 40 sampled strains, 2) ISWpi1 copies exhibit virtually identical nucleotide sequences both within and among Wolbachia genomes and possess an intact transposase gene, 3) individual ISWpi1 copies are differentially inserted among Wolbachia genomes, and 4) ISWpi1 occurs at variable copy numbers among Wolbachia genomes. Collectively, our results provide compelling evidence for intense ISWpi1 transpositional activity and frequent ISWpi1 horizontal transmission among strains during recent Wolbachia evolution. Thus, the genomes of ancient obligate endosymbionts can carry high loads of functional and transpositionally active transposable elements. Our results also indicate that Wolbachia genomes have experienced multiple and temporally distinct ISWpi1 invasions during their evolutionary history. Such recurrent exposition to new IS invasions may explain, at least partly, the unusually high density of transposable elements found in the genomes of Wolbachia endosymbionts. PMID:18562339

  18. Amoebal Endosymbiont Neochlamydia Genome Sequence Illuminates the Bacterial Role in the Defense of the Host Amoebae against Legionella pneumophila

    PubMed Central

    Ishida, Kasumi; Sekizuka, Tsuyoshi; Hayashida, Kyoko; Matsuo, Junji; Takeuchi, Fumihiko; Kuroda, Makoto; Nakamura, Shinji; Yamazaki, Tomohiro; Yoshida, Mitsutaka; Takahashi, Kaori; Nagai, Hiroki; Sugimoto, Chihiro; Yamaguchi, Hiroyuki

    2014-01-01

    Previous work has shown that the obligate intracellular amoebal endosymbiont Neochlamydia S13, an environmental chlamydia strain, has an amoebal infection rate of 100%, but does not cause amoebal lysis and lacks transferability to other host amoebae. The underlying mechanism for these observations remains unknown. In this study, we found that the host amoeba could completely evade Legionella infection. The draft genome sequence of Neochlamydia S13 revealed several defects in essential metabolic pathways, as well as unique molecules with leucine-rich repeats (LRRs) and ankyrin domains, responsible for protein-protein interaction. Neochlamydia S13 lacked an intact tricarboxylic acid cycle and had an incomplete respiratory chain. ADP/ATP translocases, ATP-binding cassette transporters, and secretion systems (types II and III) were well conserved, but no type IV secretion system was found. The number of outer membrane proteins (OmcB, PomS, 76-kDa protein, and OmpW) was limited. Interestingly, genes predicting unique proteins with LRRs (30 genes) or ankyrin domains (one gene) were identified. Furthermore, 33 transposases were found, possibly explaining the drastic genome modification. Taken together, the genomic features of Neochlamydia S13 explain the intimate interaction with the host amoeba to compensate for bacterial metabolic defects, and illuminate the role of the endosymbiont in the defense of the host amoebae against Legionella infection. PMID:24747986

  19. Intracellular Neutralization of Virus by Immunoglobulin A Antibodies

    NASA Astrophysics Data System (ADS)

    Mazanec, Mary B.; Kaetzel, Charlotte S.; Lamm, Michael E.; Fletcher, David; Nedrud, John G.

    1992-08-01

    IgA is thought to neutralize viruses at the epithelial surface of mucous membranes by preventing their attachment. Since IgA, a polymeric immunoglobulin, is transported through the lining of epithelial cells by the polymeric-immunoglobulin receptor and since viruses are obligate intracellular parasites, we hypothesized that IgA antibodies may also interfere with viral replication by binding to newly synthesized viral proteins within infected cells. Polarized monolayers of Madin-Darby canine kidney epithelial cells expressing the polymeric-immunoglobulin receptor were infected on the apical surface with Sendai virus. Anti-Sendai virus IgA monoclonal antibody delivered from the basolateral surface colocalized with viral protein within the cell, as documented by immunofluorescence. More importantly, anti-viral IgA reduced virus titers >1000-fold (P < 0.0001) in apical supernatants and >10-fold (P < 0.0001) in cell lysates from monolayers treated with anti-viral IgA compared with those treated with either anti-viral IgG or an irrelevant IgA monoclonal antibody. We believe that the differences in viral titers between cell layers treated with specific IgA, which enters the epithelial cell by binding to the polymeric-immunoglobulin receptor, and those treated with specific IgG, which does not enter the cells, or irrelevant IgA indicate that specific intracellular IgA antibodies can inhibit viral replication. Thus, in addition to the classical role of humoral antibodies in extracellular defense, IgA antibody may be able to neutralize microbial pathogens intracellularly, giving IgA a role in host defense that has traditionally been reserved for cell-mediated immunity.

  20. Employer obligations versus fulfillment and the effects on organizational citizenship and innovative work

    Microsoft Academic Search

    Sandra K. Newton; Linda I. Nowak

    This research investigated the relationship among discrepancies between the employers' obligations and the level of fulfillment of those obligations and the information technology (IT) professionals' citizenship and innovative work behaviors. The dimensional approach to the psychological contract was used to demonstrate the IT professional's perceptions of their employer's obligations and the level of fulfillment of those obligations. Survey data from

  1. A Longitudinal Study of Family Obligation and Depressive Symptoms Among Chinese American Adolescents

    Microsoft Academic Search

    Linda P. Juang; Jeffrey T. Cookston

    2009-01-01

    The purpose of this 2-year, 3-wave longitudinal study of Chinese American adolescents was to examine how family obligation behaviors and attitudes change over time; how gender, nativity, and birth order predict these trajectories; and whether family obligation relates to depressive symptoms. Findings suggest that family obligation behaviors decreased over the 2-year period but that family obligation attitudes were stable. Moreover,

  2. Microsporidia Are Natural Intracellular Parasites of the Nematode Caenorhabditis elegans

    PubMed Central

    Troemel, Emily R; Félix, Marie-Anne; Whiteman, Noah K; Barrière, Antoine; Ausubel, Frederick M

    2008-01-01

    For decades the soil nematode Caenorhabditis elegans has been an important model system for biology, but little is known about its natural ecology. Recently, C. elegans has become the focus of studies of innate immunity and several pathogens have been shown to cause lethal intestinal infections in C. elegans. However none of these pathogens has been shown to invade nematode intestinal cells, and no pathogen has been isolated from wild-caught C. elegans. Here we describe an intracellular pathogen isolated from wild-caught C. elegans that we show is a new species of microsporidia. Microsporidia comprise a large class of eukaryotic intracellular parasites that are medically and agriculturally important, but poorly understood. We show that microsporidian infection of the C. elegans intestine proceeds through distinct stages and is transmitted horizontally. Disruption of a conserved cytoskeletal structure in the intestine called the terminal web correlates with the release of microsporidian spores from infected cells, and appears to be part of a novel mechanism by which intracellular pathogens exit from infected cells. Unlike in bacterial intestinal infections, the p38 MAPK and insulin/insulin-like growth factor (IGF) signaling pathways do not appear to play substantial roles in resistance to microsporidian infection in C. elegans. We found microsporidia in multiple wild-caught isolates of Caenorhabditis nematodes from diverse geographic locations. These results indicate that microsporidia are common parasites of C. elegans in the wild. In addition, the interaction between C. elegans and its natural microsporidian parasites provides a system in which to dissect intracellular intestinal infection in vivo and insight into the diversity of pathogenic mechanisms used by intracellular microbes. PMID:19071962

  3. Microsporidia are natural intracellular parasites of the nematode Caenorhabditis elegans.

    PubMed

    Troemel, Emily R; Félix, Marie-Anne; Whiteman, Noah K; Barrière, Antoine; Ausubel, Frederick M

    2008-12-01

    For decades the soil nematode Caenorhabditis elegans has been an important model system for biology, but little is known about its natural ecology. Recently, C. elegans has become the focus of studies of innate immunity and several pathogens have been shown to cause lethal intestinal infections in C. elegans. However none of these pathogens has been shown to invade nematode intestinal cells, and no pathogen has been isolated from wild-caught C. elegans. Here we describe an intracellular pathogen isolated from wild-caught C. elegans that we show is a new species of microsporidia. Microsporidia comprise a large class of eukaryotic intracellular parasites that are medically and agriculturally important, but poorly understood. We show that microsporidian infection of the C. elegans intestine proceeds through distinct stages and is transmitted horizontally. Disruption of a conserved cytoskeletal structure in the intestine called the terminal web correlates with the release of microsporidian spores from infected cells, and appears to be part of a novel mechanism by which intracellular pathogens exit from infected cells. Unlike in bacterial intestinal infections, the p38 MAPK and insulin/insulin-like growth factor (IGF) signaling pathways do not appear to play substantial roles in resistance to microsporidian infection in C. elegans. We found microsporidia in multiple wild-caught isolates of Caenorhabditis nematodes from diverse geographic locations. These results indicate that microsporidia are common parasites of C. elegans in the wild. In addition, the interaction between C. elegans and its natural microsporidian parasites provides a system in which to dissect intracellular intestinal infection in vivo and insight into the diversity of pathogenic mechanisms used by intracellular microbes. PMID:19071962

  4. Glutamine synthetase desensitizes differentiated adipocytes to proinflammatory stimuli by raising intracellular glutamine levels.

    PubMed

    Palmieri, Erika Mariana; Spera, Iolanda; Menga, Alessio; Infantino, Vittoria; Iacobazzi, Vito; Castegna, Alessandra

    2014-12-20

    The role of glutamine synthetase (GS) during adipocyte differentiation is unclear. Here, we assess the impact of GS on the adipocytic response to a proinflammatory challenge at different differentiation stages. GS expression at the late stages of differentiation desensitized mature adipocytes to bacterial lipopolysaccharide (LPS) by increasing intracellular glutamine levels. Furthermore, LPS-activated mature adipocytes were unable to produce inflammatory mediators; LPS sensitivity was rescued following GS inhibition and the associated drop in intracellular glutamine levels. The ability of adipocytes to differentially respond to LPS during differentiation negatively correlates to GS expression and intracellular glutamine levels. Hence, modulation of intracellular glutamine levels by GS expression represents an endogenous mechanism through which mature adipocytes control the inflammatory response. PMID:25451225

  5. Influence of dTMP on the Phenotypic Appearance and Intracellular Persistence of Staphylococcus aureus?

    PubMed Central

    Zander, Johannes; Besier, Silke; Saum, Stephan H.; Dehghani, Faramarz; Loitsch, Stefan; Brade, Volker; Wichelhaus, Thomas A.

    2008-01-01

    Thymidine-dependent small-colony variants (SCVs) of Staphylococcus aureus are frequently associated with persistent and recurrent infections in cystic fibrosis patients. The phenotypic appearance of S. aureus SCVs or normal-colony variants (NCVs) is postulated to be affected by the intracellular amount of dTMP. This hypothesis was proven by metabolic pathway assays revealing altered intracellular dTMP concentrations, followed by investigation of the associated phenotype. Inhibition of the staphylococcal thymidylate synthase, which generated intracellular dTMP from dUMP, using 5-fluorouracil and co-trimoxazole resulted in an SCV phenotype. Inhibition of a nucleoside transporter, which provided the bacterial cell with extracellular thymidine, caused growth inhibition of SCVs. In turn, reversion of SCVs to NCVs was achieved by supplying extracellular dTMP. High-performance liquid chromatography additionally confirmed the intracellular lack of dTMP in SCVs, in contrast to NCVs. Moreover, the dTMP concentration is postulated to influence the intracellular persistence of S. aureus. Cell culture experiments with cystic fibrosis cells revealed that clinical and co-trimoxazole-induced SCVs with a diminished amount of dTMP showed significantly better intracellular persistence than NCVs. In conclusion, these results show that the dTMP concentration plays a key role in both the phenotypic appearance and the intracellular persistence of S. aureus. PMID:18160477

  6. Influence of dTMP on the phenotypic appearance and intracellular persistence of Staphylococcus aureus.

    PubMed

    Zander, Johannes; Besier, Silke; Saum, Stephan H; Dehghani, Faramarz; Loitsch, Stefan; Brade, Volker; Wichelhaus, Thomas A

    2008-04-01

    Thymidine-dependent small-colony variants (SCVs) of Staphylococcus aureus are frequently associated with persistent and recurrent infections in cystic fibrosis patients. The phenotypic appearance of S. aureus SCVs or normal-colony variants (NCVs) is postulated to be affected by the intracellular amount of dTMP. This hypothesis was proven by metabolic pathway assays revealing altered intracellular dTMP concentrations, followed by investigation of the associated phenotype. Inhibition of the staphylococcal thymidylate synthase, which generated intracellular dTMP from dUMP, using 5-fluorouracil and co-trimoxazole resulted in an SCV phenotype. Inhibition of a nucleoside transporter, which provided the bacterial cell with extracellular thymidine, caused growth inhibition of SCVs. In turn, reversion of SCVs to NCVs was achieved by supplying extracellular dTMP. High-performance liquid chromatography additionally confirmed the intracellular lack of dTMP in SCVs, in contrast to NCVs. Moreover, the dTMP concentration is postulated to influence the intracellular persistence of S. aureus. Cell culture experiments with cystic fibrosis cells revealed that clinical and co-trimoxazole-induced SCVs with a diminished amount of dTMP showed significantly better intracellular persistence than NCVs. In conclusion, these results show that the dTMP concentration plays a key role in both the phenotypic appearance and the intracellular persistence of S. aureus. PMID:18160477

  7. Intracellular calcium channels in protozoa.

    PubMed

    Docampo, Roberto; Moreno, Silvia N J; Plattner, Helmut

    2014-09-15

    Ca(2+)-signaling pathways and intracellular Ca(2+) channels are present in protozoa. Ancient origin of inositol 1,4,5-trisphosphate receptors (IP3Rs) and other intracellular channels predates the divergence of animals and fungi as evidenced by their presence in the choanoflagellate Monosiga brevicollis, the closest known relative to metazoans. The first protozoan IP3R cloned, from the ciliate Paramecium, displays strong sequence similarity to the rat type 3 IP3R. This ciliate has a large number of IP3- and ryanodine(Ry)-like receptors in six subfamilies suggesting the evolutionary adaptation to local requirements for an expanding diversification of vesicle trafficking. IP3Rs have also been functionally characterized in trypanosomatids, where they are essential for growth, differentiation, and establishment of infection. The presence of the mitochondrial calcium uniporter (MCU) in a number of protozoa indicates that mitochondrial regulation of Ca(2+) signaling is also an early appearance in evolution, and contributed to the discovery of the molecular nature of this channel in mammalian cells. There is only sequence evidence for the occurrence of two-pore channels (TPCs), transient receptor potential Ca(2+) channels (TRPCs) and intracellular mechanosensitive Ca(2+)-channels in Paramecium and in parasitic protozoa. PMID:24291099

  8. Stochastic models of intracellular transport

    NASA Astrophysics Data System (ADS)

    Bressloff, Paul C.; Newby, Jay M.

    2013-01-01

    The interior of a living cell is a crowded, heterogenuous, fluctuating environment. Hence, a major challenge in modeling intracellular transport is to analyze stochastic processes within complex environments. Broadly speaking, there are two basic mechanisms for intracellular transport: passive diffusion and motor-driven active transport. Diffusive transport can be formulated in terms of the motion of an overdamped Brownian particle. On the other hand, active transport requires chemical energy, usually in the form of adenosine triphosphate hydrolysis, and can be direction specific, allowing biomolecules to be transported long distances; this is particularly important in neurons due to their complex geometry. In this review a wide range of analytical methods and models of intracellular transport is presented. In the case of diffusive transport, narrow escape problems, diffusion to a small target, confined and single-file diffusion, homogenization theory, and fractional diffusion are considered. In the case of active transport, Brownian ratchets, random walk models, exclusion processes, random intermittent search processes, quasi-steady-state reduction methods, and mean-field approximations are considered. Applications include receptor trafficking, axonal transport, membrane diffusion, nuclear transport, protein-DNA interactions, virus trafficking, and the self-organization of subcellular structures.

  9. A microfluidic device for physical trapping and electrical lysis of bacterial cells

    NASA Astrophysics Data System (ADS)

    Bao, Ning; Lu, Chang

    2008-05-01

    In this letter, we report a simple microfluidic device that integrates the capture of bacterial cells using a microscale bead array and the rapid electrical lysis for release of intracellular materials. We study the retention of Escherichia coli cells with different concentrations in this type of bead array and the optimal electrical parameters for the electroporative release of intracellular proteins. Our design provides a simple solution to the extraction of intracellular materials from a bacterial cell population based entirely on physical methods without applying chemical or biological reagents.

  10. Mechanisms of Obligatory Intracellular Infection with Anaplasma phagocytophilum

    PubMed Central

    Rikihisa, Yasuko

    2011-01-01

    Summary: Anaplasma phagocytophilum persists in nature by cycling between mammals and ticks. Human infection by the bite of an infected tick leads to a potentially fatal emerging disease called human granulocytic anaplasmosis. A. phagocytophilum is an obligatory intracellular bacterium that replicates inside mammalian granulocytes and the salivary gland and midgut cells of ticks. A. phagocytophilum evolved the remarkable ability to hijack the regulatory system of host cells. A. phagocytophilum alters vesicular traffic to create an intracellular membrane-bound compartment that allows replication in seclusion from lysosomes. The bacterium downregulates or actively inhibits a number of innate immune responses of mammalian host cells, and it upregulates cellular cholesterol uptake to acquire cholesterol for survival. It also upregulates several genes critical for the infection of ticks, and it prolongs tick survival at freezing temperatures. Several host factors that exacerbate infection have been identified, including interleukin-8 (IL-8) and cholesterol. Host factors that overcome infection include IL-12 and gamma interferon (IFN-?). Two bacterial type IV secretion effectors and several bacterial proteins that associate with inclusion membranes have been identified. An understanding of the molecular mechanisms underlying A. phagocytophilum infection will foster the development of creative ideas to prevent or treat this emerging tick-borne disease. PMID:21734244

  11. Mechanisms of obligatory intracellular infection with Anaplasma phagocytophilum.

    PubMed

    Rikihisa, Yasuko

    2011-07-01

    Anaplasma phagocytophilum persists in nature by cycling between mammals and ticks. Human infection by the bite of an infected tick leads to a potentially fatal emerging disease called human granulocytic anaplasmosis. A. phagocytophilum is an obligatory intracellular bacterium that replicates inside mammalian granulocytes and the salivary gland and midgut cells of ticks. A. phagocytophilum evolved the remarkable ability to hijack the regulatory system of host cells. A. phagocytophilum alters vesicular traffic to create an intracellular membrane-bound compartment that allows replication in seclusion from lysosomes. The bacterium downregulates or actively inhibits a number of innate immune responses of mammalian host cells, and it upregulates cellular cholesterol uptake to acquire cholesterol for survival. It also upregulates several genes critical for the infection of ticks, and it prolongs tick survival at freezing temperatures. Several host factors that exacerbate infection have been identified, including interleukin-8 (IL-8) and cholesterol. Host factors that overcome infection include IL-12 and gamma interferon (IFN-?). Two bacterial type IV secretion effectors and several bacterial proteins that associate with inclusion membranes have been identified. An understanding of the molecular mechanisms underlying A. phagocytophilum infection will foster the development of creative ideas to prevent or treat this emerging tick-borne disease. PMID:21734244

  12. Complete Bacteriophage Transfer in a Bacterial Endosymbiont (Wolbachia) Determined by Targeted

    E-print Network

    Bordenstein, Seth

    Complete Bacteriophage Transfer in a Bacterial Endosymbiont (Wolbachia) Determined by Targeted Bacteriophage flux can cause the majority of genetic diversity in free-living bacteria. This tenet of bacterial the reductive forces of the intracellular lifestyle. To test whether bacteriophages transfer as single genes

  13. Cyclic Dimeric GMP Signaling Regulates Intracellular Aggregation, Sessility, and Growth of Ehrlichia chaffeensis ? §

    PubMed Central

    Kumagai, Yumi; Matsuo, Junji; Cheng, Zhihui; Hayakawa, Yoshihiro; Rikihisa, Yasuko

    2011-01-01

    Cyclic dimeric GMP (c-di-GMP), a bacterial second messenger, is known to regulate bacterial biofilm and sessility. Replication of an obligatory intracellular pathogen, Ehrlichia chaffeensis, is characterized by formation of bacterial aggregates called morulae inside membrane-bound inclusions. When E. chaffeensis matures into an infectious form, morulae become loose to allow bacteria to exit from host cells to infect adjacent cells. E. chaffeensis expresses a sensor kinase, PleC, and a cognate response regulator, PleD, which can produce c-di-GMP. A hydrophobic c-di-GMP antagonist, 2?-O-di(tert-butyldimethysilyl)-c-di-GMP (CDGA) inhibits E. chaffeensis internalization into host cells by facilitating degradation of some bacterial surface proteins via endogenous serine proteases. In the present study, we found that PleC and PleD were upregulated synchronously during exponential growth of bacteria, concomitant with increased morula size. While CDGA did not affect host cells, when infected cells were treated with CDGA, bacterial proliferation was inhibited, morulae became less compact, and the intracellular movement of bacteria was enhanced. Concurrently, CDGA treatment facilitated the extracellular release of bacteria with lower infectivity than those spontaneously released from sham-treated cells. Addition of CDGA to isolated inclusions induced dispersion of the morulae, degradation of an inclusion matrix protein TRP120, and bacterial intrainclusion movement, all of which were blocked by a serine protease inhibitor. These results suggest that c-di-GMP signaling regulates aggregation and sessility of E. chaffeensis within the inclusion through stabilization of matrix proteins by preventing the serine protease activity, which is associated with bacterial intracellular proliferation and maturation. PMID:21788390

  14. The Legionella effector RidL inhibits retrograde trafficking to promote intracellular replication.

    PubMed

    Finsel, Ivo; Ragaz, Curdin; Hoffmann, Christine; Harrison, Christopher F; Weber, Stephen; van Rahden, Vanessa A; Johannes, Ludger; Hilbi, Hubert

    2013-07-17

    The bacteria causing Legionnaires' disease, Legionella pneumophila, replicate intracellularly within unique Legionella-containing vacuoles (LCVs). LCV formation involves a type IV secretion system (T4SS) that translocates effector proteins into host cells. We show that the T4SS effector RidL localizes to LCVs, supports intracellular bacterial growth, and alters retrograde trafficking, in which selected proteins are transported from endosomes to the Golgi. The retromer complex that mediates retrograde trafficking localizes to LCVs independently of RidL and restricts intracellular bacterial growth. RidL binds the Vps29 retromer subunit and the lipid PtdIns(3)P, which localizes retromer components to membranes. Additionally, specific retromer cargo receptors and sorting nexins that mediate protein capture and membrane remodeling preferentially localize to LCVs in the absence of ridL. Ectopic RidL production inhibits retrograde trafficking, and L. pneumophila blocks retrograde transport at endosome exit sites in a ridL-dependent manner. Collectively, these findings suggest that RidL inhibits retromer function to promote intracellular bacterial replication. PMID:23870312

  15. 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

  16. Intracellular Salmonella inhibit antigen presentation by dendritic cells.

    PubMed

    Cheminay, Cédric; Möhlenbrink, Annette; Hensel, Michael

    2005-03-01

    Dendritic cells (DC) are important APCs linking innate and adaptive immunity. During analysis of the intracellular activities of Salmonella enterica in DC, we observed that viable bacteria suppress Ag-dependent T cell proliferation. This effect was dependent on the induction of inducible NO synthase by DC and on the function of virulence genes in Salmonella pathogenicity island 2 (SPI2). Intracellular activities of Salmonella did not affect the viability, Ag uptake, or maturation of DC, but resulted in reduced presentation of antigenic peptides by MHC class II molecules. Increased resistance to reinfection was observed after vaccination of mice with SPI2-deficient Salmonella compared with mice vaccinated with SPI2-proficient Salmonella, and this correlated with an increased amount of CD4(+) as well as CD8(+) T cells. Our study is the first example of interference of an intracellular bacterial pathogen with Ag presentation by DC. The subversion of DC functions is a novel strategy deployed by this pathogen to escape immune defense, colonize host organs, and persist in the infected host. PMID:15728500

  17. 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.

  18. 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.

  19. Bacterial Enteritides of Poultry

    Microsoft Academic Search

    ROBERT E. PORTER

    Enteric bacterial infections in poultry pose a threat to intestinal health and can contribute to poor feed efficiency and livability of a flock. A variety of enteric bacterial diseases are recognized in poultry. Three of these bacterial diseases, necrotic enteritis, ulcerative enteritis, and spirochetosis, primarily infect the intestine, whereas other bacterial diseases, such as salmonellosis, colibacillosis, mycobacteriosis, erysipelas, and fowl

  20. Intracellular Proton Access in a Cl?/H+ Antiporter

    PubMed Central

    Lim, Hyun-Ho; Shane, Tania; Miller, Christopher

    2012-01-01

    Chloride-transporting membrane proteins of the CLC family appear in two distinct mechanistic flavors: H+-gated Cl? channels and Cl?/H+ antiporters. Transmembrane H+ movement is an essential feature of both types of CLC. X-ray crystal structures of CLC antiporters show the Cl? ion pathway through these proteins, but the H+ pathway is known only inferentially by two conserved glutamate residues that act as way-stations for H+ in its path through the protein. The extracellular-facing H+ transfer glutamate becomes directly exposed to aqueous solution during the transport cycle, but the intracellular glutamate E203, Gluin, is buried within the protein. Two regions, denoted “polar” and “interfacial,” at the intracellular surface of the bacterial antiporter CLC-ec1 are examined here as possible pathways by which intracellular aqueous protons gain access to Gluin. Mutations at multiple residues of the polar region have little effect on antiport rates. In contrast, mutation of E202, a conserved glutamate at the protein–water boundary of the interfacial region, leads to severe slowing of the Cl?/H+ antiport rate. An X-ray crystal structure of E202Y, the most strongly inhibited of these substitutions, shows an aqueous portal leading to Gluin physically blocked by cross-subunit interactions; moreover, this mutation has only minimal effect on a monomeric CLC variant, which necessarily lacks such interactions. The several lines of experiments presented argue that E202 acts as a water-organizer that creates a proton conduit connecting intracellular solvent with Gluin. PMID:23239938

  1. Real-Time monitoring of intracellular wax ester metabolism

    PubMed Central

    2011-01-01

    Background Wax esters are industrially relevant molecules exploited in several applications of oleochemistry and food industry. At the moment, the production processes mostly rely on chemical synthesis from rather expensive starting materials, and therefore solutions are sought from biotechnology. Bacterial wax esters are attractive alternatives, and especially the wax ester metabolism of Acinetobacter sp. has been extensively studied. However, the lack of suitable tools for rapid and simple monitoring of wax ester metabolism in vivo has partly restricted the screening and analyses of potential hosts and optimal conditions. Results Based on sensitive and specific detection of intracellular long-chain aldehydes, specific intermediates of wax ester synthesis, bacterial luciferase (LuxAB) was exploited in studying the wax ester metabolism in Acinetobacter baylyi ADP1. Luminescence was detected in the cultivation of the strain producing wax esters, and the changes in signal levels could be linked to corresponding cell growth and wax ester synthesis phases. Conclusions The monitoring system showed correlation between wax ester synthesis pattern and luminescent signal. The system shows potential for real-time screening purposes and studies on bacterial wax esters, revealing new aspects to dynamics and role of wax ester metabolism in bacteria. PMID:21961954

  2. The intracellular galactoglycome in Trichoderma reesei during growth on lactose.

    PubMed

    Karaffa, Levente; Coulier, Leon; Fekete, Erzsébet; Overkamp, Karin M; Druzhinina, Irina S; Mikus, Marianna; Seiboth, Bernhard; Novák, Levente; Punt, Peter J; Kubicek, Christian P

    2013-06-01

    Lactose (1,4-0-?-D-galactopyranosyl-D-glucose) is used as a soluble carbon source for the production of cellulases and hemicellulases for-among other purposes-use in biofuel and biorefinery industries. The mechanism how lactose induces cellulase formation in T. reesei is enigmatic, however. Previous results from our laboratory raised the hypothesis that intermediates from the two galactose catabolic pathway may give rise to the accumulation of intracellular oligogalactosides that could act as inducer. Here we have therefore used high-performance anion-exchange chromatography-mass spectrometry to study the intracellular galactoglycome of T. reesei during growth on lactose, in T. reesei mutants impaired in galactose catabolism, and in strains with different cellulase productivities. Lactose, allo-lactose, and lactulose were detected in the highest amounts in all strains, and two trisaccharides (Gal-?-1,6-Gal-?-1,4-Glc/Fru and Gal-?-1,4-Gal-?-1,4-Glc/Fru) also accumulated to significant levels. Glucose and galactose, as well as four further oligosaccharides (Gal-?-1,3/1,4/1,6-Gal; Gal-?-1,2-Glc) were only detected in minor amounts. In addition, one unknown disaccharide (Hex-?-1,1-Hex) and four trisaccharides were also detected. The accumulation of the unknown hexose disaccharide was shown to correlate with cellulase formation in the improved mutant strains as well as the galactose pathway mutants, and Gal-?-1,4-Gal-?-1,4-Glc/Fru and two other unknown hexose trisaccharides correlated with cellulase production only in the pathway mutants, suggesting that these compounds could be involved in cellulase induction by lactose. The nature of these oligosaccharides, however, suggests their formation by transglycosylation rather than by glycosyltransferases. Based on our results, the obligate nature of both galactose catabolic pathways for this induction must have another biochemical basis than providing substrates for inducer formation. PMID:23299458

  3. 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

  4. 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

    Manzano-Marín, Alejandro; Latorre, Amparo

    2014-07-01

    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

  5. 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

  6. 34 CFR 75.707 - When obligations are made.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    34 ? Education ? 1 ? 2013-07-01 ? 2013-07-01 ? false ? When obligations are made. ? 75.707 ? Section 75.707 ? Education ? Office of the Secretary, Department of Education ? DIRECT GRANT PROGRAMS ? What Are the Administrative Responsibilities of a Grantee? ? General Administrative Responsibilities...

  7. Oxidation of Inorganic Sulfur Compounds by Obligately Organotrophic Bacteria

    Microsoft Academic Search

    D. Yu. Sorokin

    2003-01-01

    New data obtained by the author and other researchers on two different groups of obligately heterotrophic bacteria capable of inorganic sulfur oxidation are reviewed. Among culturable marine and (halo)alkaliphilic heterotrophs oxidizing sulfur compounds (thiosulfate and, much less actively, elemental sulfur and sulfide) incompletely to tetrathionate, representatives of the gammaproteobacteria, especially from the Halomonas group, dominate. Some denitrifying species from this

  8. Who can be morally obligated to be a vegetarian?

    Microsoft Academic Search

    Evelyn Pluhar

    1992-01-01

    Kathryn Paxton George has recently argued that vegetarianism cannot be a moral obligation for most human beings, even if Tom Regan is correct in arguing that humans and certain nonhuman animals are equally inherently valuable. She holds that Regan's liberty principle permits humans to kill and eat innocent others who have a right to life, provided that doing so prevents

  9. 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

  10. 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)

  11. Are YA Novelists Morally Obligated To Offer Their Readers Hope?

    ERIC Educational Resources Information Center

    Ritter, John H.

    2003-01-01

    Presents a letter from a sixth-grade student to the author and presents his response letter which are found in a compilation of author/reader correspondence called "Letters of Hope." Discusses the role of the storyteller and considers if writers of young adult literature feel an obligation to provide hope for their readers. (SG)

  12. 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.

  13. Asset retirement obligations: a reporting concern for healthcare facilities.

    PubMed

    Berg, Gary G; Bayes, Paul E; Morgan, Robert G

    2008-11-01

    FASB statements and SEC guidelines give direction as to how healthcare organizations should account for their asset retirement obligations (AROs) where environmental issues are concerned. A key consideration is that current costs associated with environmental problems, such as encapsulating asbestos, are to be accounted for as part of an asset's cost and depreciated over the asset's remaining life. PMID:18990844

  14. Revisional metabolic/bariatric surgery: a moral obligation.

    PubMed

    Buchwald, Henry

    2015-03-01

    Revisional metabolic/bariatric surgery is a moral obligation; for not to perform revisional surgery is a denial of the precepts of our discipline and an abandonment of the underprivileged population who has placed its trust and future in our hands. PMID:25344464

  15. Obama states obligation to act on climate change

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2012-11-01

    Obama states obligation to act on climate change Noting increased global temperatures, Arctic ice melt, and severe weather events, President Barack Obama said that climate change is real and called for a conversation across the country to determine what can be done about it.

  16. Civic Engagement in Teacher Education: Activities or Obligation?

    ERIC Educational Resources Information Center

    Erickson, Lynnette B.

    2011-01-01

    Some might question whether teacher education programs have an obligation to promote or enhance the teaching of civic responsibility and engagement, especially if they believe that the primary purpose of education is to prepare students to enter the workforce or be successful as individuals. However, others have a more encompassing view of…

  17. Eradication of intracellular Francisella tularensis in THP-1 human macrophages with a novel autophagy inducing agent

    PubMed Central

    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 AR-12 induces autophagy in THP-1 macrophages, as indicated by increased autophagosome formation, and potently inhibits the intracellular survival of F. tularensis (type A strain, Schu S4) and F. novicida in macrophages in association with increased bacterial co-localization with autophagosomes. The effect of AR-12 on intracellular F. novicida was fully reversed in the presence of the autophagy inhibitor, 3-methyl adenine or the lysosome inhibitor, chloroquine. Intracellular F. novicida were not susceptible to the inhibitory activity of AR-12 added at 12 h post-infection in THP-1 macrophages, and this lack of susceptibility was independent of the intracellular location of bacteria. Conclusion Together, AR-12 represents a proof-of-principle that intracellular F. tularensis can be eradicated by small-molecule agents that target innate immunity. PMID:20003180

  18. The Genome Sequence of the Obligately Chemolithoautotrophic, Facultatively Anaerobic Bacterium Thiobacillus denitrificans

    PubMed Central

    Beller, Harry R.; Chain, Patrick S. G.; Letain, Tracy E.; Chakicherla, Anu; Larimer, Frank W.; Richardson, Paul M.; Coleman, Matthew A.; Wood, Ann P.; Kelly, Donovan P.

    2006-01-01

    The complete genome sequence of Thiobacillus denitrificans ATCC 25259 is the first to become available for an obligately chemolithoautotrophic, sulfur-compound-oxidizing, ?-proteobacterium. Analysis of the 2,909,809-bp genome will facilitate our molecular and biochemical understanding of the unusual metabolic repertoire of this bacterium, including its ability to couple denitrification to sulfur-compound oxidation, to catalyze anaerobic, nitrate-dependent oxidation of Fe(II) and U(IV), and to oxidize mineral electron donors. Notable genomic features include (i) genes encoding c-type cytochromes totaling 1 to 2 percent of the genome, which is a proportion greater than for almost all bacterial and archaeal species sequenced to date, (ii) genes encoding two [NiFe]hydrogenases, which is particularly significant because no information on hydrogenases has previously been reported for T. denitrificans and hydrogen oxidation appears to be critical for anaerobic U(IV) oxidation by this species, (iii) a diverse complement of more than 50 genes associated with sulfur-compound oxidation (including sox genes, dsr genes, and genes associated with the AMP-dependent oxidation of sulfite to sulfate), some of which occur in multiple (up to eight) copies, (iv) a relatively large number of genes associated with inorganic ion transport and heavy metal resistance, and (v) a paucity of genes encoding organic-compound transporters, commensurate with obligate chemolithoautotrophy. Ultimately, the genome sequence of T. denitrificans will enable elucidation of the mechanisms of aerobic and anaerobic sulfur-compound oxidation by ?-proteobacteria and will help reveal the molecular basis of this organism's role in major biogeochemical cycles (i.e., those involving sulfur, nitrogen, and carbon) and groundwater restoration. PMID:16452431

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. Apoptosis of human intestinal epithelial cells after bacterial invasion.

    PubMed Central

    Kim, J M; Eckmann, L; Savidge, T C; Lowe, D C; Witthöft, T; Kagnoff, M F

    1998-01-01

    Epithelial cells that line the human intestinal mucosa are the initial site of host invasion by bacterial pathogens. The studies herein define apoptosis as a new category of intestinal epithelial cell response to bacterial infection. Human colon epithelial cells are shown to undergo apoptosis following infection with invasive enteric pathogens, such as Salmonella or enteroinvasive Escherichia coli. In contrast to the rapid onset of apoptosis seen after bacterial infection of mouse monocyte-macrophage cell lines, the commitment of human intestinal epithelial cell lines to undergo apoptosis is delayed for at least 6 h after bacterial infection, requires bacterial entry and replication, and the ensuing phenotypic expression of apoptosis is delayed for 12-18 h after bacterial entry. TNF-alpha and nitric oxide, which are produced as components of the intestinal epithelial cell proinflammatory program in the early period after bacterial invasion, play an important role in the later induction and regulation of the epithelial cell apoptotic program. Apoptosis in response to bacterial infection may function to delete infected and damaged epithelial cells and restore epithelial cell growth regulation and epithelial integrity that are altered during the course of enteric infection. The delay in onset of epithelial cell apoptosis after bacterial infection may be important both to the host and the invading pathogen since it provides sufficient time for epithelial cells to generate signals important for the activation of mucosal inflammation and concurrently allows invading bacteria time to adapt to the intracellular environment before invading deeper mucosal layers. PMID:9819367

  5. 24 CFR 811.110 - Refunding of obligations issued to finance Section 8 projects.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 31 CFR 1010.940 - Photographic or other reproductions of Government obligations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Photographic or other reproductions of Government obligations. 1010...1010.940 Photographic or other reproductions of Government obligations. Nothing...authorize the microfilming or other reproduction of: (a) Currency or other...

  12. 31 CFR 103.52 - Photographic or other reproductions of Government obligations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Photographic or other reproductions of Government obligations. 103... § 103.52 Photographic or other reproductions of Government obligations. Nothing...authorize the microfilming or other reproduction of (a) Currency or other...

  13. 31 CFR 1010.940 - Photographic or other reproductions of Government obligations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Photographic or other reproductions of Government obligations. 1010...1010.940 Photographic or other reproductions of Government obligations. Nothing...authorize the microfilming or other reproduction of: (a) Currency or other...

  14. 31 CFR 1010.940 - Photographic or other reproductions of Government obligations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Photographic or other reproductions of Government obligations. 1010...1010.940 Photographic or other reproductions of Government obligations. Nothing...authorize the microfilming or other reproduction of: (a) Currency or other...

  15. 31 CFR 1010.940 - Photographic or other reproductions of Government obligations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Photographic or other reproductions of Government obligations. 1010...1010.940 Photographic or other reproductions of Government obligations. Nothing...authorize the microfilming or other reproduction of: (a) Currency or other...

  16. 18 CFR 292.303 - Electric utility obligations under this subpart.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Electric utility obligations under this subpart...AND COGENERATION Arrangements Between Electric Utilities and Qualifying Cogeneration...Policies Act of 1978 § 292.303 Electric utility obligations under this...

  17. 12 CFR 1511.5 - Obligations of Funding Corporation; no adverse claims.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Obligations of Funding Corporation; no adverse claims. ...DEPARTMENT OF THE TREASURY RESOLUTION FUNDING CORPORATION BOOK-ENTRY PROCEDURE § 1511.5 Obligations of Funding Corporation; no adverse...

  18. 12 CFR 1511.5 - Obligations of Funding Corporation; no adverse claims.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Obligations of Funding Corporation; no adverse claims. ...DEPARTMENT OF THE TREASURY RESOLUTION FUNDING CORPORATION BOOK-ENTRY PROCEDURE § 1511.5 Obligations of Funding Corporation; no adverse...

  19. 12 CFR 1511.5 - Obligations of Funding Corporation; no adverse claims.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Obligations of Funding Corporation; no adverse claims. ...DEPARTMENT OF THE TREASURY RESOLUTION FUNDING CORPORATION BOOK-ENTRY PROCEDURE § 1511.5 Obligations of Funding Corporation; no adverse...

  20. 12 CFR 1511.5 - Obligations of Funding Corporation; no adverse claims.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Obligations of Funding Corporation; no adverse claims. ...DEPARTMENT OF THE TREASURY RESOLUTION FUNDING CORPORATION BOOK-ENTRY PROCEDURE § 1511.5 Obligations of Funding Corporation; no adverse...

  1. 12 CFR 1511.5 - Obligations of Funding Corporation; no adverse claims.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Obligations of Funding Corporation; no adverse claims. ...DEPARTMENT OF THE TREASURY RESOLUTION FUNDING CORPORATION BOOK-ENTRY PROCEDURE § 1511.5 Obligations of Funding Corporation; no adverse...

  2. 28 CFR 45.10 - Procedures to promote compliance with crime victims' rights obligations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Procedures to promote compliance with crime victims' rights obligations. 45.10... Procedures to promote compliance with crime victims' rights obligations. (a...that relate to protection of the rights of crime victims. See 18 U.S.C. 3771....

  3. 42 CFR 1004.10 - Statutory obligations of practitioners and other persons.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... false Statutory obligations of practitioners and other persons. 1004.10 Section...IMPOSITION OF SANCTIONS ON HEALTH CARE PRACTITIONERS AND PROVIDERS OF HEALTH CARE SERVICES...1004.10 Statutory obligations of practitioners and other persons. It is the...

  4. 42 CFR 1004.10 - Statutory obligations of practitioners and other persons.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... false Statutory obligations of practitioners and other persons. 1004.10 Section...IMPOSITION OF SANCTIONS ON HEALTH CARE PRACTITIONERS AND PROVIDERS OF HEALTH CARE SERVICES...1004.10 Statutory obligations of practitioners and other persons. It is the...

  5. 42 CFR 1004.10 - Statutory obligations of practitioners and other persons.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... false Statutory obligations of practitioners and other persons. 1004.10 Section...IMPOSITION OF SANCTIONS ON HEALTH CARE PRACTITIONERS AND PROVIDERS OF HEALTH CARE SERVICES...1004.10 Statutory obligations of practitioners and other persons. It is the...

  6. 42 CFR 1004.10 - Statutory obligations of practitioners and other persons.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... false Statutory obligations of practitioners and other persons. 1004.10 Section...IMPOSITION OF SANCTIONS ON HEALTH CARE PRACTITIONERS AND PROVIDERS OF HEALTH CARE SERVICES...1004.10 Statutory obligations of practitioners and other persons. It is the...

  7. 42 CFR 1004.10 - Statutory obligations of practitioners and other persons.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... false Statutory obligations of practitioners and other persons. 1004.10 Section...IMPOSITION OF SANCTIONS ON HEALTH CARE PRACTITIONERS AND PROVIDERS OF HEALTH CARE SERVICES...1004.10 Statutory obligations of practitioners and other persons. It is the...

  8. Origins, Diversity, and Diversification of the Native Hawaiian Leafhoppers (Hemiptera: Cicadellidae: Nesophrosyne) and Their Obligate Endosymbionts

    E-print Network

    O'Grady, Patrick M.

    Origins, Diversity, and Diversification of the Native Hawaiian Leafhoppers (Hemiptera: Cicadellidae Leafhoppers (Hemiptera: Cicadellidae: Nesophrosyne) and Their Obligate Endosymbionts Copyright 2012 By Gordon Leafhoppers (Hemiptera: Cicadellidae: Nesophrosyne) and Their Obligate Endosymbionts by Gordon Morse Bennett

  9. 43 CFR 3137.76 - What happens if I do not meet a continuing development obligation?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...happens if I do not meet a continuing development obligation? 3137.76 Section...Agreements-National Petroleum Reserve-Alaska Development Requirements § 3137.76 ...happens if I do not meet a continuing development obligation? (a) After...

  10. 43 CFR 3137.71 - What must I do to meet continuing development obligations?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...What must I do to meet continuing development obligations? 3137.71 Section...Agreements-National Petroleum Reserve-Alaska Development Requirements § 3137.71 What must I do to meet continuing development obligations? (a) Once you...

  11. 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....

  12. 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....

  13. Moral obligations of nurses and physicians in neonatal end-of-life care

    PubMed Central

    Epstein, Elizabeth Gingell

    2013-01-01

    The aim of this study was to explore the obligations of nurses and physicians in providing end-of-life care. Nineteen nurses and 11 physicians from a single newborn intensive care unit participated. Using content analysis, an overarching obligation of creating the best possible experience for infants and parents was identified, within which two categories of obligations (decision making and the end of life itself) emerged. Obligations in decision making included talking to parents and timing withdrawal. End-of-life obligations included providing options, preparing parents, being with, advocating, creating peace and normalcy, and providing comfort. Nurses and physicians perceived obligations in both categories, although nurse obligations centered on the end of life while physician obligations focused on decision making. The findings demonstrate that, although the ultimate goal is shared by both disciplines, the paths to achieving that goal are often different. This has important implications for collaboration, communication, and improving the end of life. PMID:20801960

  14. 32 CFR 220.2 - Statutory obligation of third party payer to pay.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...COLLECTION FROM THIRD PARTY PAYERS OF REASONABLE CHARGES FOR HEALTHCARE SERVICES § 220.2 Statutory obligation of third party...obligation to pay the United States the reasonable charges for healthcare services provided in or through any facility of...

  15. 32 CFR 220.2 - Statutory obligation of third party payer to pay.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...COLLECTION FROM THIRD PARTY PAYERS OF REASONABLE CHARGES FOR HEALTHCARE SERVICES § 220.2 Statutory obligation of third party...obligation to pay the United States the reasonable charges for healthcare services provided in or through any facility of...

  16. 32 CFR 220.2 - Statutory obligation of third party payer to pay.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...COLLECTION FROM THIRD PARTY PAYERS OF REASONABLE CHARGES FOR HEALTHCARE SERVICES § 220.2 Statutory obligation of third party...obligation to pay the United States the reasonable charges for healthcare services provided in or through any facility of...

  17. 32 CFR 220.2 - Statutory obligation of third party payer to pay.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...COLLECTION FROM THIRD PARTY PAYERS OF REASONABLE CHARGES FOR HEALTHCARE SERVICES § 220.2 Statutory obligation of third party...obligation to pay the United States the reasonable charges for healthcare services provided in or through any facility of...

  18. 32 CFR 220.2 - Statutory obligation of third party payer to pay.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...COLLECTION FROM THIRD PARTY PAYERS OF REASONABLE CHARGES FOR HEALTHCARE SERVICES § 220.2 Statutory obligation of third party...obligation to pay the United States the reasonable charges for healthcare services provided in or through any facility of...

  19. 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...

  20. 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...

  1. 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...

  2. 40 CFR 152.97 - Rights and obligations of data submitters.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 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...

  3. SERS nanosensors for intracellular redox potential measurements 

    E-print Network

    Auchinvole, Craig Alexander R

    2012-06-22

    Redox regulation and homeostasis are critically important in the regulation of cell function; however, there are significant challenges in quantitatively measuring and monitoring intracellular redox potentials. The work ...

  4. NOD2, an intracellular innate immune sensor involved in host defense and Crohn's disease

    Microsoft Academic Search

    W Strober; T Watanabe

    2011-01-01

    Nucleotide-binding oligomerization domain 2 (NOD2) is an intracellular sensor for small peptides derived from the bacterial cell wall component, peptidoglycan. Recent studies have uncovered unexpected functions of NOD2 in innate immune responses such as induction of type I interferon and facilitation of autophagy; moreover, they have disclosed extensive cross-talk between NOD2 and Toll-like receptors, which has an indispensable role both

  5. Efficacy of tetracycline encapsulated O-carboxymethyl chitosan nanoparticles against intracellular infections of Staphylococcus aureus.

    PubMed

    Maya, S; Indulekha, S; Sukhithasri, V; Smitha, K T; Nair, Shantikumar V; Jayakumar, R; Biswas, Raja

    2012-11-01

    Intracellular bacterial infections are recurrent, persistent and are difficult to treat because of poor penetration and limited availability of antibiotics within macrophages and epithelial cells. We developed biocompatible, 200 nm sized tetracycline encapsulated O-carboxymethyl chitosan nanoparticles (Tet-O-CMC Nps) via ionic gelation for its sustained delivery of Tet into cells. S. aureus binds and aggregates with Tet-O-CMC Nps increasing drug concentrations at the infection site. Tet-O-CMC Nps were sixfold more effective in killing intracellular S. aureus compared to Tet alone in HEK-293 and differentiated THP1 macrophage cells proving it to be an efficient nanomedicine to treat intracellular S. aureus infections. PMID:22705573

  6. 26 CFR 1.551-3 - Deduction for obligations of the United States and its instrumentalities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...obligations of the United States and its instrumentalities. 1.551-3 Section 1.551-3...obligations of the United States and its instrumentalities. (a) Each United States...obligations of the United States or its instrumentalities (as specified in sections...

  7. 25 CFR 163.42 - Obligated service and breach of contract.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Obligated service and breach of contract. 163.42 Section 163...Training § 163.42 Obligated service and breach of contract. (a) Obligated service...receipt of the request for waiver. (b) Breach of contract. Any individual who...

  8. 26 CFR 1.1037-1 - Certain exchanges of United States obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...value of $930, at which price such obligation is initially...obligation there was no intention to call it before maturity...the same as the issue price of the obligation...Example 1. (a) A purchases in the market for...old bond). The issue price of the new bond for...

  9. 40 CFR 80.1106 - To whom does the Renewable Volume Obligation apply?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false To whom does the Renewable Volume Obligation apply? 80.1106 Section...80.1106 To whom does the Renewable Volume Obligation apply? (a) (1...that it has satisfied the Renewable Volume Obligation for that compliance...

  10. 40 CFR 80.1106 - To whom does the Renewable Volume Obligation apply?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false To whom does the Renewable Volume Obligation apply? 80.1106 Section...80.1106 To whom does the Renewable Volume Obligation apply? (a) (1...that it has satisfied the Renewable Volume Obligation for that compliance...

  11. 40 CFR 80.1106 - To whom does the Renewable Volume Obligation apply?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false To whom does the Renewable Volume Obligation apply? 80.1106 Section...80.1106 To whom does the Renewable Volume Obligation apply? (a) (1...that it has satisfied the Renewable Volume Obligation for that compliance...

  12. 40 CFR 80.1106 - To whom does the Renewable Volume Obligation apply?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false To whom does the Renewable Volume Obligation apply? 80.1106 Section...80.1106 To whom does the Renewable Volume Obligation apply? (a) (1...that it has satisfied the Renewable Volume Obligation for that compliance...

  13. 40 CFR 80.1106 - To whom does the Renewable Volume Obligation apply?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false To whom does the Renewable Volume Obligation apply? 80.1106 Section...80.1106 To whom does the Renewable Volume Obligation apply? (a) (1...that it has satisfied the Renewable Volume Obligation for that compliance...

  14. 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)...

  15. 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)...

  16. 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)...

  17. 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)...

  18. 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)...

  19. Origin of a complex key innovation in an obligate insectplant mutualism

    E-print Network

    Krenn, Harald W.

    Origin of a complex key innovation in an obligate insect­plant mutualism Olle Pellmyr* and Harald W. The well known obligate pollination mutualism between yuccas and yucca moths is a major model system. Obligate mutualisms between plants and pollinators provide some of the most apparent examples

  20. 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

  1. Bacterial Gene Transfer

    NSDL National Science Digital Library

    Roberta Ellington (Northwestern University; )

    1991-01-01

    This resource provides detailed instructions for carrying out several laboratory exercises relating to bacterial transformation and conjugation. In this multi-session experiment, students are exposed to various techniques in microbiology, including bacterial transformation and assay and sterile techniques.

  2. Bacterial Vaginosis (BV)

    MedlinePLUS

    ... NICHD Research Information Clinical Trials Resources and Publications Bacterial Vaginosis (BV): Condition Information Skip sharing on social media links Share this: Page Content What is BV? Bacterial vaginosis, more commonly called BV, is an infection that ...

  3. 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

  4. Maintenance of Vacuole Integrity by Bacterial Pathogens

    PubMed Central

    Creasey, Elizabeth A.; Isberg, Ralph R.

    2014-01-01

    Many intracellular bacterial pathogens reside within a membrane-bound compartment. The biogenesis of these vacuolar compartments is complex, involving subversion of host cell secretory pathways by bacterial proteins. In recent years it has become clear that disruption of vacuole biogenesis may result in membrane rupture and escape of bacteria into the host cell cytosol. Correct modulation of the host cell cytoskeleton, signalling molecules such as small GTPases and the lipids of the vacuole membrane have all been shown to be critical in the maintenance of vacuole integrity. Increasing evidence suggests that vacuole rupture may result from aberrant mechanical forces exerted on the vacuole, possibly due to a defect in vacuole expansion. PMID:24581692

  5. Facultative versus obligate nitrogen fixation strategies and their ecosystem consequences.

    PubMed

    Menge, Duncan N L; Levin, Simon A; Hedin, Lars O

    2009-10-01

    Symbiotic nitrogen (N) fixers are critical components of many terrestrial ecosystems. There is evidence that some N fixers fix N at the same rate regardless of environmental conditions (a strategy we call obligate), while others adjust N fixation to meet their needs (a strategy we call facultative). Although these strategies are likely to have qualitatively different impacts on their environment, the relative effectiveness and ecosystem-level impacts of each strategy have not been explored. Using a simple mathematical model, we determine the best facultative strategy and show that it excludes any obligate strategy (fixer or nonfixer) in our basic model. To provide an explanation for the existence of nonfixers and obligate fixers, we show that both costs of being facultative and time lags inherent in the process of N fixation can select against facultative N fixers and also produce the seemingly paradoxical patterns of sustained N limitation and N richness. Finally, we speculate on why the costs and lags may differ between temperate and tropical regions and thus whether they can explain patterns in both biomes simultaneously. PMID:19694561

  6. 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

  7. Intracellular recognition of pathogens and autophagy as an innate immune host defence.

    PubMed

    Yano, Tamaki; Kurata, Shoichiro

    2011-08-01

    Pathogen recognition is the first and crucial step in innate immunity. Molecular families involved in the recognition of pathogens and activation of the innate immune responses in immunoreactive cells include the Toll-like receptor family in mammals and the peptidoglycan recognition protein (PGRP) family in Drosophila, which sense microorganisms in an extracellular or luminal compartment. Other emerging families are the intracellular recognition molecules for bacteria, such as nucleotide binding and oligomerization domain-like receptors in mammals and PGRP--LE in Drosophila, several of which have been shown to detect structures of bacterial peptidoglycan in the host cell cytosol. Exciting advances in recent studies on autophagy indicate that macroautophagy (referred to here as autophagy) is selectively induced by intracellular recognition molecules and has a crucial role in the elimination of intracellular pathogens, including bacteria, viruses and parasites. This review discusses recent studies related to intracellular recognition molecules and innate immune responses to intracellular pathogens, and highlights the role of autophagy in innate immunity. PMID:21729928

  8. Intracellular recognition of pathogens and autophagy as an innate immune host defence

    PubMed Central

    Yano, Tamaki; Kurata, Shoichiro

    2011-01-01

    Pathogen recognition is the first and crucial step in innate immunity. Molecular families involved in the recognition of pathogens and activation of the innate immune responses in immunoreactive cells include the Toll-like receptor family in mammals and the peptidoglycan recognition protein (PGRP) family in Drosophila, which sense microorganisms in an extracellular or luminal compartment. Other emerging families are the intracellular recognition molecules for bacteria, such as nucleotide binding and oligomerization domain-like receptors in mammals and PGRP–LE in Drosophila, several of which have been shown to detect structures of bacterial peptidoglycan in the host cell cytosol. Exciting advances in recent studies on autophagy indicate that macroautophagy (referred to here as autophagy) is selectively induced by intracellular recognition molecules and has a crucial role in the elimination of intracellular pathogens, including bacteria, viruses and parasites. This review discusses recent studies related to intracellular recognition molecules and innate immune responses to intracellular pathogens, and highlights the role of autophagy in innate immunity. PMID:21729928

  9. Intracellular Oceanospirillales bacteria inhabit gills of Acesta bivalves.

    PubMed

    Jensen, Sigmund; Duperron, Sébastien; Birkeland, Nils-Kåre; Hovland, Martin

    2010-12-01

    A novel bacterium was discovered in the gills of the large bivalve Acesta excavata (Limidae) from coral reefs on the northeast Atlantic margin near the shelf break of the fishing ground Haltenbanken of Norway, and confirmed present in A. excavata from a rock-wall in the Trondheimsfjord. Purified gill DNA contained one dominant bacterial rRNA operon as indicated from analysis of broad range bacterial PCR amplicons in denaturant gradient gels, in clone libraries and by direct sequencing. The sequences originated from an unknown member of the order Oceanospirillales and its 16S rRNA gene fell within a clade of strictly marine invertebrate-associated Gammaproteobacteria. Visual inspection by fluorescent in situ hybridization and transmission electron microscopy indicated a pleomorphic bacterium with no visible cell wall, located in aggregates inside vacuoles scattered within the gill cells cytoplasm. Intracellular Oceanospirillales exist in bathymodiolin mussels (parasites), Osedax worms and whiteflies (symbionts). This bacterium apparently lives in a specific association with the Acesta. PMID:21044098

  10. Optimal killing for obligate killers: the evolution of life histories and virulence of semelparous parasites.

    PubMed Central

    Ebert, D; Weisser, W W

    1997-01-01

    Many viral, bacterial and protozoan parasites of invertebrates first propagate inside their host without releasing any transmission stages and then kill their host to release all transmission stages at once. Life history and the evolution of virulence of these obligately killing parasites are modelled, assuming that within-host growth is density dependent. We find that the parasite should kill the host when its per capita growth rate falls to the level of the host mortality rate. The parasite should kill its host later when the carrying capacity, K, is higher, but should kill it earlier when the parasite-independent host mortality increases or when the parasite has a higher birth rate. When K(t), for parasite growth, is not constant over the duration of an infection, but increases with time, the parasite should kill the host around the stage when the growth rate of the carrying capacity decelerates strongly. In case that K(t) relates to host body size, this deceleration in growth is around host maturation. PMID:9263465

  11. Stochastic resonance in an intracellular genetic perceptron

    NASA Astrophysics Data System (ADS)

    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.

  12. 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

  13. Module No: 410112Sources of ObligationModule Title: Co-requisite: Effects of ObligationsIntroduction of LawPre-requisite

    E-print Network

    students with the basic as well as advanced knowledge in Sources of Obligation in Jordan Law 2. Develop of this module, a student will be able to: A/1 Understand the basic principles and concepts of obligation. Practical Training (Depends on module Practice Discussions regarding Jordan's civil law texts relevant

  14. Catabolism of host-derived compounds during extracellular bacterial infections

    PubMed Central

    Meadows, Jamie A.; Wargo, Matthew J.

    2014-01-01

    Efficient catabolism of host-derived compounds is essential for bacterial survival and virulence. While these links in intracellular bacteria are well-studied, such studies in extracellular bacteria lag behind, mostly for technical reasons. The field has identified important metabolic pathways, but the mechanisms by which they impact infection and in particular, establishing the importance of a compound’s catabolism versus alternate metabolic roles has been difficult. In this review we will examine evidence for catabolism during extracellular bacterial infections in animals and known or potential roles in virulence. In the process, we point out key gaps in the field that will require new or newly adapted techniques. PMID:24038340

  15. Staphylococcus aureus promotes autophagy by decreasing intracellular cAMP levels

    PubMed Central

    Mestre, María Belén; Colombo, María Isabel

    2012-01-01

    Staphylococcus aureus is an intracellular bacterium responsible for serious infectious processes. This pathogen escapes from the phagolysosomal pathway into the cytoplasm, a strategy that allows intracellular bacterial replication and survival with the consequent killing of the eukaryotic host cell and spreading of the infection. S. aureus is able to secrete several virulence factors such as enzymes and toxins. Our recent findings indicate that the main virulence factor of S. aureus, the pore-forming toxin ?-hemolysin (Hla), is the secreted factor responsible for the activation of an alternative autophagic pathway. We have demonstrated that this noncanonical autophagic response is inhibited by artificially elevating the intracellular levels of cAMP. This effect is mediated by RAPGEF3/EPAC (Rap guanine nucleotide exchange factor (GEF)3/exchange protein activated by cAMP), a cAMP downstream effector that functions as a GEF for the small GTPase Rap. We have presented evidence that RAPGEF3 and RAP2B, through calpain activation, are the proteins involved in the regulation of Hla and S. aureus-induced autophagy. In addition, we have found that both, RAPGEF3 and RAP2B, are recruited to the S. aureus–containing phagosome. Of note, adding purified ?-toxin or infecting the cells with S. aureus leads to a decrease in intracellular cAMP levels, which promotes autophagy induction, a response that favors pathogen intracellular survival, as previously demonstrated. We have identified some key signaling molecules involved in the autophagic response upon infection with a bacterial pathogen, which have important implications in understanding innate immune defense mechanisms. PMID:23047465

  16. 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.

  17. Introduction Magnetotactic bacteria (MTB) biomineralize intracellular, membrane-

    E-print Network

    Walker, Lawrence R.

    Introduction Magnetotactic bacteria (MTB) biomineralize intracellular, membrane- bounded, magnetic in the environment. Abstract Magnetotactic bacteria is the categorical name for a group of prokaryotes of this study is on two magnetite-producing, magnetotactic sulfate-reducing bacteria (SRB), Desulfovibrio

  18. INTRACELLULAR OXIDATION-REDUCTION STUDIES

    PubMed Central

    Cohen, Barnett; Chambers, Robert; Reznikoff, Paul

    1928-01-01

    Twenty-five oxidation-reduction indicators were injected in oxidized or reduced form into Amoeba dubia and Amœba proteus under controlled conditions of oxygen access. (1) Under anaerobiosis the ameba was able to reduce completely all the reversible oxidation-reduction indicators down to and including indigo disulfonate. (2) Under anaerobiosis the ameba was unable to reoxidize six of the most easily oxidizable indicators. (3) Under aerobiosis the ameba was able to reduce completely all the indicators down to and including 1-naphthol-2-sulfonate indo-2, 6-dichlorophenol. Toluylene blue, methylene blue and indigo tetrasulfonate were sometimes completely and sometimes only partly reduced, depending on the quantity of indicator injected and the duration of observation. (4) The time of reduction varied approximately with the size of the injection. Reduction was more rapid under anaerobiosis than under aerobiosis, more rapid in active than in sluggish cells and was retarded by toxic compounds. (5) Sulfonated compounds were somewhat toxic, as a rule. In interpreting reduction phenomena of micro injection, it is necessary to take into consideration the intensity, capacity and rate factors. It then becomes apparent that the ameba has a high reducing potential lying on the rH scale below the zone of indigo disulfonate. The reducing capacity of the ameba seems to be relatively great in the region of the simple indophenols and of a progressively diminishing magnitude as the zone of the indigos is approached. Material of high reduction potential appears to be generated within the ameba at a measurable rate. These phenomena, observed in the interior of the cell with the aid of indicators, parallel very closely those found in reduction electrode studies on bacterial cultures. PMID:19872422

  19. Facial bacterial infections: folliculitis.

    PubMed

    Laureano, Ana Cristina; Schwartz, Robert A; Cohen, Philip J

    2014-01-01

    Facial bacterial infections are most commonly caused by infections of the hair follicles. Wherever pilosebaceous units are found folliculitis can occur, with the most frequent bacterial culprit being Staphylococcus aureus. We review different origins of facial folliculitis, distinguishing bacterial forms from other infectious and non-infectious mimickers. We distinguish folliculitis from pseudofolliculitis and perifolliculitis. Clinical features, etiology, pathology, and management options are also discussed. PMID:25441463

  20. Biodegradability of bacterial surfactants

    Microsoft Academic Search

    Tânia M. S. Lima; Lorena C. Procópio; Felipe D. Brandão; André M. X. Carvalho; Marcos R. Tótola; Arnaldo C. Borges

    2011-01-01

    This work aimed at evaluating the biodegradability of different bacterial surfactants in liquid medium and in soil microcosms.\\u000a The biodegradability of biosurfactants by pure and mixed bacterial cultures was evaluated through CO2 evolution. Three bacterial strains, Acinetobacter baumanni LBBMA ES11, Acinetobacter haemolyticus LBBMA 53 and Pseudomonas sp. LBBMA 101B, used the biosurfactants produced by Bacillus sp. LBBMA 111A (mixed lipopeptide),

  1. 10th Circuit narrows obligation for job reassignment under ADA.

    PubMed

    1998-06-26

    [Name removed], an assembler at [name removed], developed chronic dermatitis and muscular injuries. [Name removed] tried to reassign [name removed] to other tasks. When [name removed] returned to work after several months of leave, [name removed] claimed it could not accommodate him. In the resulting suit, the 10th U.S. Circuit Court of Appeals ruled, contrary to Equal Employment Opportunity Commission (EEOC) guidance and decisions by a number of other circuit courts, that employers are not obliged to reassign workers to another position if a disability renders them unable to do their assigned job. PMID:11365519

  2. Chlamydia pneumoniae harness host NLRP3 inflammasome-mediated caspase-1 activation for optimal intracellular growth in murine macrophages.

    PubMed

    Itoh, Ryota; Murakami, Issaku; Chou, Bin; Ishii, Kazunari; Soejima, Toshinori; Suzuki, Toshihiko; Hiromatsu, Kenji

    2014-09-26

    Chlamydia pneumoniae is an obligate intracellular pathogen that replicates within a vacuole and acquires host cell nutrients. We show that C. pneumoniae utilizes host innate immune signaling NLRP3/ASC/caspase-1 inflammasome for intracellular growth. Bone marrow-derived macrophages (BMMs) secreted mature interleukin-1? upon infection with C. pneumoniae depending on the NLRP3 inflammasome activation. Intracellular growth of C. pneumoniae was severely impaired in BMMs from Nlrp3(-/-), Asc(-/-), and Casp1(-/-) mice but not wild type or Nlrc4(-/-) mice. Furthermore defective NLRP3 inflammasome components led to accumulation of lipid droplets inside the infected BMMs, suggesting that uptake and/or utilization of lipids is disturbed in the absence of NLRP3 inflammasome activation. These results suggest C. pneumoniae has evolved to harness both host innate immune response and NLRP3 inflammasome activation, for the acquisition of essential nutrients necessary for intracellular growth. This unique property of C. pneumoniae may shed a new light on how C. pneumoniae increase the risk of atherosclerosis and metabolic syndrome. PMID:25193701

  3. The cell-penetrating peptide, Pep-1, has activity against intracellular chlamydial growth but not extracellular forms of Chlamydia trachomatis

    PubMed Central

    Park, Narae; Yamanaka, Kinrin; Tran, Dat; Chandrangsu, Pete; Akers, Johnny C.; de Leon, Jessica C.; Morrissette, Naomi S.; Selsted, Michael E.; Tan, Ming

    2009-01-01

    Objectives In the course of studies to identify novel treatment strategies against the pathogenic bacterium, Chlamydia, we tested the carrier peptide, Pep-1, for activity against an intracellular infection. Methods Using a cell culture model of Chlamydia trachomatis infection, the effect of Pep-1 was measured by incubating the peptide with extracellular chlamydiae prior to infection, or by adding Pep-1 to the medium at varying times after infection, and assaying for inhibition of inclusion formation. Results Pep-1 had a concentration-dependent effect on chlamydial growth with 100% inhibition of inclusion formation at 8 mg/L peptide. There was a window of susceptibility during the chlamydial developmental cycle with a maximal effect when treatment was begun within 12 h of infection. Pep-1 treatment caused a severe reduction in the production of infectious progeny even when started later, when the effect on inclusion formation was minimal. Furthermore, electron micrographs showed a paucity of progeny elementary bodies (EBs) in the inclusion. In contrast, pre-incubation of EBs with Pep-1 prior to infection did not affect inclusion formation. Taken together, these findings indicate that the antichlamydial effect was specific for the intracellular stage of chlamydial infection. By comparison, Pep-1 had no antimicrobial activity against Escherichia coli and Staphylococcus aureus or the obligate intracellular parasite, Toxoplasma gondii. Conclusions Pep-1 has antichlamydial activity by preventing intracellular chlamydial growth and replication but has no effect on extracellular chlamydiae. PMID:18957395

  4. Nitric Oxide-Mediated Intracellular Growth Restriction of Pathogenic Rhodococcus equi Can Be Prevented by Iron?

    PubMed Central

    von Bargen, Kristine; Wohlmann, Jens; Taylor, Gregory Alan; Utermöhlen, Olaf; Haas, Albert

    2011-01-01

    Rhodococcus equi is an intracellular pathogen which causes pneumonia in young horses and in immunocompromised humans. R. equi arrests phagosome maturation in macrophages at a prephagolysosome stage and grows inside a privileged compartment. Here, we show that, in murine macrophages activated with gamma interferon and lipopolysaccharide, R. equi does not multiply but stays viable for at least 24 h. Whereas infection control of other intracellular pathogens by activated macrophages is executed by enhanced phagosome acidification or phagolysosome formation, by autophagy or by the interferon-inducible GTPase Irgm1, none of these mechanisms seems to control R. equi infection. Growth control by macrophage activation is fully mimicked by treatment of resting macrophages with nitric oxide donors, and inhibition of bacterial multiplication by either activation or nitric oxide donors is annihilated by cotreatment of infected macrophages with ferrous sulfate. Transcriptional analysis of the R. equi iron-regulated gene iupT demonstrates that intracellular R. equi encounters iron stress in activated, but not in resting, macrophages and that this stress is relieved by extracellular addition of ferrous sulfate. Our results suggest that nitric oxide is central to the restriction of bacterial access to iron in activated macrophages. PMID:21383050

  5. Tumor-targeting bacterial therapy: A potential treatment for oral cancer (Review)

    PubMed Central

    LIU, SAI; XU, XIAOPING; ZENG, XIN; LI, LONGJIANG; CHEN, QIANMING; LI, JING

    2014-01-01

    Certain obligate or facultative anaerobic bacteria, which exhibit an inherent ability to colonize solid tumors in vivo, may be used in tumor targeting. As genetically manipulated bacteria may actively and specifically penetrate into the tumor tissue, bacterial therapy is becoming a promising approach in the treatment of tumors. However, to the best of our knowledge, no reports have been published thus far regarding the bacterial treatment of oral cancer, one of the most common types of cancer worldwide. In this review, the progress in the understanding of bacterial strategies used in tumor-targeted therapy is discussed and particular bacterial strains that may have great therapeutic potential in oral squamous cell carcinoma (OSCC) tumor-targeted therapy are predicted as determined by previous studies. PMID:25364397

  6. Tumor-targeting bacterial therapy: A potential treatment for oral cancer (Review).

    PubMed

    Liu, Sai; Xu, Xiaoping; Zeng, Xin; Li, Longjiang; Chen, Qianming; Li, Jing

    2014-12-01

    Certain obligate or facultative anaerobic bacteria, which exhibit an inherent ability to colonize solid tumors in vivo, may be used in tumor targeting. As genetically manipulated bacteria may actively and specifically penetrate into the tumor tissue, bacterial therapy is becoming a promising approach in the treatment of tumors. However, to the best of our knowledge, no reports have been published thus far regarding the bacterial treatment of oral cancer, one of the most common types of cancer worldwide. In this review, the progress in the understanding of bacterial strategies used in tumor-targeted therapy is discussed and particular bacterial strains that may have great therapeutic potential in oral squamous cell carcinoma (OSCC) tumor-targeted therapy are predicted as determined by previous studies. PMID:25364397

  7. 76 FR 74721 - Reexamination of Roaming Obligations of Commercial Mobile Radio Service Providers and Other...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-01

    ...FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 20...Roaming Obligations of Commercial Mobile Radio Service Providers and Other Providers of Mobile Data Services AGENCY: Federal Communications Commission. ACTION:...

  8. Bacterial Community Affects Toxin Production by Gymnodinium catenatum

    PubMed Central

    Albinsson, Maria E.; Negri, Andrew P.; Blackburn, Susan I.; Bolch, Christopher J. S.

    2014-01-01

    The paralytic shellfish toxin (PST)-producing dinoflagellate Gymnodinium catenatum grows in association with a complex marine bacterial community that is both essential for growth and can alter culture growth dynamics. Using a bacterial community replacement approach, we examined the intracellular PST content, production rate, and profile of G. catenatum cultures grown with bacterial communities of differing complexity and composition. Clonal offspring were established from surface-sterilized resting cysts (produced by sexual crosses of strain GCDE06 and strain GCLV01) and grown with: 1) complex bacterial communities derived from each of the two parent cultures; 2) simplified bacterial communities composed of the G. catenatum-associated bacteria Marinobacter sp. strain DG879 or Alcanivorax sp. strain DG881; 3) a complex bacterial community associated with an untreated, unsterilized sexual cross of the parents. Toxin content (STX-equivalent per cell) of clonal offspring (134–197 fmol STX cell?1) was similar to the parent cultures (169–206 fmol STX cell?1), however cultures grown with single bacterial types contained less toxin (134–146 fmol STX cell?1) than offspring or parent cultures grown with more complex mixed bacterial communities (152–176 fmol STX cell?1). Specific toxin production rate (fmol STX day?1) was strongly correlated with culture growth rate. Net toxin production rate (fmol STX cell?1 day?1) did not differ among treatments, however, mean net toxin production rate of offspring was 8-fold lower than the parent cultures, suggesting that completion of the sexual lifecycle in laboratory cultures leads to reduced toxin production. The PST profiles of offspring cultures were most similar to parent GCDE06 with the exception of cultures grown with Marinobacter sp. DG879 which produced higher proportions of dcGTX2+3 and GC1+2, and lower proportions of C1+2 and C3+4. Our data demonstrate that the bacterial community can alter intracellular STX production of dinoflagellates. In G. catenatum the mechanism appears likely to be due to bacterial effects on dinoflagellate physiology rather than bacterial biotransformation of PST toxins. PMID:25117053

  9. Evolution of obligate pollination mutualism in New Caledonian Phyllanthus (Euphorbiaceae).

    PubMed

    Kawakita, Atsushi; Kato, Makoto

    2004-03-01

    About half a dozen obligate pollination mutualisms between plants and their seed-consuming pollinators are currently recognized, including fig-fig wasp, yucca-yucca moth, and the recently discovered Glochidion tree-Epicephala moth mutualisms. A common principle among these interactions is that the pollinators consume only a limited amount of the seed crop within a developing fruit (or fig in the case of fig-fig wasp mutualism), thereby ensuring a net benefit to plant reproduction. A novel obligate, seed-parasitic pollination mutualism between two species of New Caledonian Phyllanthus (Euphorbiaceae), a close relative of Glochidion, and Epicephala moths (Gracillariidae) is an exception to this principle. The highly specialized flowers of Phyllanthus are actively and exclusively pollinated by species-specific Epicephala moths, whose larvae consume all six ovules of the developing fruit. Some flowers pollinated by the moths remain untouched, and thus a fraction of the fruits is left intact. Additional evidence for a similar association of Epicephala moths in other Phyllanthus species suggests that this interaction is a coevolved, species-specific pollination mutualism. Implications for the evolutionary stability of the system, as well as differences in mode of interaction with respect to the Glochidion-Epicephala mutualism, are discussed. PMID:21653396

  10. The Evolutionary Pathway to Obligate Scavenging in Gyps Vultures

    PubMed Central

    Dermody, Brian J.; Tanner, Colby J.; Jackson, Andrew L.

    2011-01-01

    The evolutionary pathway to obligate scavenging in Gyps vultures remains unclear. We propose that communal roosting plays a central role in setting up the information transfer network critical for obligate scavengers in ephemeral environments and that the formation of a flotilla-like foraging group is a likely strategy for foraging Gyps vultures. Using a spatial, individual-based, optimisation model we find that the communal roost is critical for establishing the information network that enables information transfer owing to the spatial-concentration of foragers close to the roost. There is also strong selection pressure for grouping behaviour owing to the importance of maintaining network integrity and hence information transfer during foraging. We present a simple mechanism for grouping, common in many animal species, which has the added implication that it negates the requirement for roost-centric information transfer. The formation of a flotilla-like foraging group also improves foraging efficiency through the reduction of overlapping search paths. Finally, we highlight the importance of consideration of information transfer mechanisms in order to maximise the success of vulture reintroduction programmes. PMID:21931786

  11. Obligate symbionts activate immune system development in the tsetse fly.

    PubMed

    Weiss, Brian L; Maltz, Michele; Aksoy, Serap

    2012-04-01

    Many insects rely on the presence of symbiotic bacteria for proper immune system function. However, the molecular mechanisms that underlie this phenomenon are poorly understood. Adult tsetse flies (Glossina spp.) house three symbiotic bacteria that are vertically transmitted from mother to offspring during this insect's unique viviparous mode of reproduction. Larval tsetse that undergo intrauterine development in the absence of their obligate mutualist, Wigglesworthia, exhibit a compromised immune system during adulthood. In this study, we characterize the immune phenotype of tsetse that develop in the absence of all of their endogenous symbiotic microbes. Aposymbiotic tsetse (Glossina morsitans morsitans [Gmm(Apo)]) present a severely compromised immune system that is characterized by the absence of phagocytic hemocytes and atypical expression of immunity-related genes. Correspondingly, these flies quickly succumb to infection with normally nonpathogenic Escherichia coli. The susceptible phenotype exhibited by Gmm(Apo) adults can be reversed when they receive hemocytes transplanted from wild-type donor flies prior to infection. Furthermore, the process of immune system development can be restored in intrauterine Gmm(Apo) larvae when their mothers are fed a diet supplemented with Wigglesworthia cell extracts. Our finding that molecular components of Wigglesworthia exhibit immunostimulatory activity within tsetse is representative of a novel evolutionary adaptation that steadfastly links an obligate symbiont with its host. PMID:22368278

  12. Fungal and Bacterial Diseases.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fungal and bacterial diseases are important constraints to production. Recognition of diseases and information on their biology is important in disease management. This chapter is aimed at providing diagnostic information on fungal and bacterial diseases of sugar beet and their biology, epidemiolo...

  13. Esterified trityl radicals as intracellular oxygen probes.

    PubMed

    Liu, Yangping; Villamena, Frederick A; Sun, Jian; Wang, Tse-yao; Zweier, Jay L

    2009-04-01

    Triarylmethyl (trityl) radicals exhibit high stability and narrow linewidth under physiological conditions which provide high sensitivity and resolution for the measurement of O2 concentrations, 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

  14. Experimental Disturbance of Foraminiferal-Bacterial Interactions

    NASA Astrophysics Data System (ADS)

    Langezaal, A. M.; van Bergen, P. F.; van der Zwaan, G. J.

    2003-04-01

    In experiments with living foraminifera, sediment is often sieved prior to incubation in microcosms. This is done to get rid of larger predators, which disturb the sediment and destroy the meiofaunal assemblage. However, the actual sieving results in a sudden disturbance of the obligate anaerobic bacteria. While sieved, they are subjected to aerobe conditions. But also the strictly aerobic bacteria are at a disadvantage when loading the homogenized sediment in microcosms. Normally, their population occurs abundantly in the top oxygenated layer with a thickness of a couple of mm. At the onset of the experiment, however, the aerobe population is mixed through the sediment to become relatively reduced in the top layer. The effects of these disturbances are ill known but might affect the outcome of the experimental foraminiferal and biogeochemical studies substantially. Benthic foraminifera migrate to their natural in-sediment position within three weeks after disturbance. The geochemistry is restored even quicker to the natural situation and it is assumed generally that equilibrium in the sediment has re-established after three weeks (Ernst et al., 2000, Duijnstee et al., 2001). However, some studies suggest that bacterial activity does not recover from the sieving process (Federly et al., 1986; Findley et al., 1990; Gilbert et al., 1995; Schafer et al., 2001) and our data indicate that the bacterial population suffers greatly. We tested an experimental design that has less influence on the bacterial standing stock. The sieving procedure was avoided, intact sediment columns were retrieved from the sea floor and macrofauna was removed by flushing the cores with Argon. In this way the structure of the sediment was kept intact, and no specific groups of bacteria are advantaged at the start of the experiment. The impact of the experimental designs on the outcome of foraminiferal studies is discussed.

  15. 7, 787822, 2010 Increased bacterial

    E-print Network

    Poggiale, Jean-Christophe

    BGD 7, 787­822, 2010 Increased bacterial growth efficiency with environmental variability M if available. Increased bacterial growth efficiency with environmental variability: results from DOC­822, 2010 Increased bacterial growth efficiency with environmental variability M. Eichinger et al. Title

  16. Autophagy enhances bacterial clearance during P. aeruginosa lung infection.

    PubMed

    Junkins, Robert D; Shen, Ann; Rosen, Kirill; McCormick, Craig; Lin, Tong-Jun

    2013-01-01

    Pseudomonas aeruginosa is an opportunistic bacterial pathogen which is the leading cause of morbidity and mortality among cystic fibrosis patients. Although P. aeruginosa is primarily considered an extacellular pathogen, recent reports have demonstrated that throughout the course of infection the bacterium acquires the ability to enter and reside within host cells. Normally intracellular pathogens are cleared through a process called autophagy which sequesters and degrades portions of the cytosol, including invading bacteria. However the role of autophagy in host defense against P. aeruginosa in vivo remains unknown. Understanding the role of autophagy during P. aeruginosa infection is of particular importance as mutations leading to cystic fibrosis have recently been shown to cause a blockade in the autophagy pathway, which could increase susceptibility to infection. Here we demonstrate that P. aeruginosa induces autophagy in mast cells, which have been recognized as sentinels in the host defense against bacterial infection. We further demonstrate that inhibition of autophagy through pharmacological means or protein knockdown inhibits clearance of intracellular P. aeruginosa in vitro, while pharmacologic induction of autophagy significantly increased bacterial clearance. Finally we find that pharmacological manipulation of autophagy in vivo effectively regulates bacterial clearance of P. aeruginosa from the lung. Together our results demonstrate that autophagy is required for an effective immune response against P. aeruginosa infection in vivo, and suggest that pharmacological interventions targeting the autophagy pathway could have considerable therapeutic potential in the treatment of P. aeruginosa lung infection. PMID:24015228

  17. Autophagy Enhances Bacterial Clearance during P. aeruginosa Lung Infection

    PubMed Central

    Junkins, Robert D.; Shen, Ann; Rosen, Kirill; McCormick, Craig; Lin, Tong-Jun

    2013-01-01

    Pseudomonas aeruginosa is an opportunistic bacterial pathogen which is the leading cause of morbidity and mortality among cystic fibrosis patients. Although P. aeruginosa is primarily considered an extacellular pathogen, recent reports have demonstrated that throughout the course of infection the bacterium acquires the ability to enter and reside within host cells. Normally intracellular pathogens are cleared through a process called autophagy which sequesters and degrades portions of the cytosol, including invading bacteria. However the role of autophagy in host defense against P. aeruginosa in vivo remains unknown. Understanding the role of autophagy during P. aeruginosa infection is of particular importance as mutations leading to cystic fibrosis have recently been shown to cause a blockade in the autophagy pathway, which could increase susceptibility to infection. Here we demonstrate that P. aeruginosa induces autophagy in mast cells, which have been recognized as sentinels in the host defense against bacterial infection. We further demonstrate that inhibition of autophagy through pharmacological means or protein knockdown inhibits clearance of intracellular P. aeruginosa in vitro, while pharmacologic induction of autophagy significantly increased bacterial clearance. Finally we find that pharmacological manipulation of autophagy in vivo effectively regulates bacterial clearance of P. aeruginosa from the lung. Together our results demonstrate that autophagy is required for an effective immune response against P. aeruginosa infection in vivo, and suggest that pharmacological interventions targeting the autophagy pathway could have considerable therapeutic potential in the treatment of P. aeruginosa lung infection. PMID:24015228

  18. 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

  19. Fluorescent nanothermometers for intracellular thermal sensing.

    PubMed

    Jaque, Daniel; Rosal, Blanca Del; Rodríguez, Emma Martín; Maestro, Laura Martínez; Haro-González, Patricia; Solé, José García

    2014-05-01

    The importance of high-resolution intracellular thermal sensing and imaging in the field of modern biomedicine has boosted the development of novel nanosized fluorescent systems (fluorescent nanothermometers) as the next generation of probes for intracellular thermal sensing and imaging. This thermal mapping requires fluorescent nanothermometers with good biocompatibility and high thermal sensitivity in order to obtain submicrometric and subdegree spatial and thermal resolutions, respectively. This review describes the different nanosized systems used up to now for intracellular thermal sensing and imaging. We also include the later advances in molecular systems based on fluorescent proteins for thermal mapping. A critical overview of the state of the art and the future perspective is also included. PMID:24978463

  20. Translating intracellular calcium signaling into models.

    PubMed

    Thul, Rüdiger

    2014-05-01

    The rich experimental data on intracellular calcium has put theoreticians in an ideal position to derive models of intracellular calcium signaling. Over the last 25 years, a large number of modeling frameworks have been suggested. Here, I will review some of the milestones of intracellular calcium modeling with a special emphasis on calcium-induced calcium release (CICR) through inositol-1,4,5-trisphosphate and ryanodine receptors. I will highlight key features of CICR and how they are represented in models as well as the challenges that theoreticians face when translating our current understanding of calcium signals into equations. The selected examples demonstrate that a successful model provides mechanistic insights into the molecular machinery of the Ca²? signaling toolbox and determines the contribution of local Ca²? release to global Ca²? patterns, which at the moment cannot be resolved experimentally. PMID:24786496

  1. Intracellular metabolite levels shape sulfur isotope fractionation during microbial sulfate respiration.

    PubMed

    Wing, Boswell A; Halevy, Itay

    2014-12-23

    We present a quantitative model for sulfur isotope fractionation accompanying bacterial and archaeal dissimilatory sulfate respiration. By incorporating independently available biochemical data, the model can reproduce a large number of recent experimental fractionation measurements with only three free parameters: (i) the sulfur isotope selectivity of sulfate uptake into the cytoplasm, (ii) the ratio of reduced to oxidized electron carriers supporting the respiration pathway, and (iii) the ratio of in vitro to in vivo levels of respiratory enzyme activity. Fractionation is influenced by all steps in the dissimilatory pathway, which means that environmental sulfate and sulfide levels control sulfur isotope fractionation through the proximate influence of intracellular metabolites. Although sulfur isotope fractionation is a phenotypic trait that appears to be strain specific, we show that it converges on near-thermodynamic behavior, even at micromolar sulfate levels, as long as intracellular sulfate reduction rates are low enough (<1 fmol H2S?cell(-1)?d(-1)). PMID:25362045

  2. Bacterial Type IV Secretion Systems: Versatile Virulence Machines

    PubMed Central

    Voth, Daniel E.; Broederdorf, Laura J.; Graham, Joseph G.

    2013-01-01

    Many bacterial pathogens employ multicomponent protein complexes to deliver macromolecules directly into their eukaryotic host cell to promote infection. Some Gram-negative pathogens use a versatile type IV secretion system (T4SS) that can translocate DNA or proteins into host cells. T4SSs represent major bacterial virulence determinants and have recently been the focus of intense research efforts designed to better understand and combat infectious diseases. Interestingly, although the two major classes of T4SSs function in a similar manner to secrete proteins, the translocated “effectors” vary substantially from one organism to another. In fact, differing effector repertoires likely contribute to organism-specific host cell interactions and disease outcomes. In this review, we discuss the current state of T4SS research, with an emphasis on intracellular bacterial pathogens of humans and the diverse array of translocated effectors used to manipulate host cells. PMID:22324993

  3. Female-biased obligate strategies in a partially migratory population.

    PubMed

    Fudickar, Adam M; Schmidt, Andreas; Hau, Michaela; Quetting, Michael; Partecke, Jesko

    2013-07-01

    Partial migration occurs when a breeding population consists of seasonal migrants and year-round residents. Although it is common among birds, the basis of individual movement decisions within partially migratory populations is still unresolved. Over 4 years, we used state of the art tracking techniques, a combination of geolocators and radio transmitters, to follow individual European blackbirds Turdus merula year round from a partially migratory population to determine individual strategies and departure and arrival dates. The individual-based tracking combined with measures of energetic and hormonal (corticosterone) state enabled us to distinguish between obligate and facultative migration and to test several classical hypotheses of partial migration: the 'Arrival Time'-, 'Dominance'- and 'Thermal Tolerance'-hypotheses. Two distinct periods of departures from the breeding grounds were observed during the study; one in early autumn, and another during the midst of winter. Although blackbirds that migrated in autumn were never observed overwintering within 300 km of the study site, four individuals that departed in the winter were observed within 40 km. Females were significantly more likely to migrate in autumn than males but there was no difference in the age or body size of migrants and non migrants in autumn. Just prior to autumn migration, migrants had higher fat scores than non migrants and tended to have higher concentrations of baseline corticosterone, but similar concentrations of triglycerides. Unlike autumn migrants, we found no difference between the tendencies of males versus females to depart in winter, nor did we find any difference in body size or age of individuals that departed in the winter. Autumn migration was sex biased and resembled obligate migration. Our results provide strong support for the 'Arrival Time' hypothesis for partial migration in the autumn. We found no clear support for the 'Dominance' or 'Thermal Tolerance' hypotheses. By tracking individuals year round, we were able to identify a second period of departures. Overall, these results suggest the co-occurrence of obligate autumn migrants, winter movements and sedentary individuals within a single population. PMID:23363245

  4. NMR measurements of intracellular ions in hypertension

    NASA Astrophysics Data System (ADS)

    Veniero, Joseph C.; Gupta, R. K.

    1993-08-01

    The NMR methods for the measurement of intracellular free Na+, K+, Mg2+, Ca2+, and H+ are introduced. The recent literature is then presented showing applications of these methods to cells and tissues from hypertensive animal model systems, and humans with essential hypertension. The results support the hypothesis of consistent derangement of the intracellular ionic environment in hypertension. The theory that this derangement may be a common link in the disease states of high blood pressure and abnormal insulin and glucose metabolism, which are often associated clinically, is discussed.

  5. ABC transporters: bacterial exporters.

    PubMed Central

    Fath, M J; Kolter, R

    1993-01-01

    The ABC transporters (also called traffic ATPases) make up a large superfamily of proteins which share a common function and a common ATP-binding domain. ABC transporters are classified into three major groups: bacterial importers (the periplasmic permeases), eukaryotic transporters, and bacterial exporters. We present a comprehensive review of the bacterial ABC exporter group, which currently includes over 40 systems. The bacterial ABC exporter systems are functionally subdivided on the basis of the type of substrate that each translocates. We describe three main groups: protein exporters, peptide exporters, and systems that transport nonprotein substrates. Prototype exporters from each group are described in detail to illustrate our current understanding of this protein family. The prototype systems include the alpha-hemolysin, colicin V, and capsular polysaccharide exporters from Escherichia coli, the protease exporter from Erwinia chrysanthemi, and the glucan exporters from Agrobacterium tumefaciens and Rhizobium meliloti. Phylogenetic analysis of the ATP-binding domains from 29 bacterial ABC exporters indicates that the bacterial ABC exporters can be divided into two primary branches. One branch contains the transport systems where the ATP-binding domain and the membrane-spanning domain are present on the same polypeptide, and the other branch contains the systems where these domains are found on separate polypeptides. Differences in substrate specificity do not correlate with evolutionary relatedness. A complete survey of the known and putative bacterial ABC exporters is included at the end of the review. PMID:8302219

  6. 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

  7. A type IV translocated Legionella cysteine phytase counteracts intracellular growth restriction by phytate.

    PubMed

    Weber, Stephen; Stirnimann, Christian U; Wieser, Mara; Frey, Daniel; Meier, Roger; Engelhardt, Sabrina; Li, Xiaodan; Capitani, Guido; Kammerer, Richard A; Hilbi, Hubert

    2014-12-01

    The causative agent of Legionnaires' pneumonia, Legionella pneumophila, colonizes diverse environmental niches, including biofilms, plant material, and protozoa. In these habitats, myo-inositol hexakisphosphate (phytate) is prevalent and used as a phosphate storage compound or as a siderophore. L. pneumophila replicates in protozoa and mammalian phagocytes within a unique "Legionella-containing vacuole." The bacteria govern host cell interactions through the Icm/Dot type IV secretion system (T4SS) and ?300 different "effector" proteins. Here we characterize a hitherto unrecognized Icm/Dot substrate, LppA, as a phytate phosphatase (phytase). Phytase activity of recombinant LppA required catalytically essential cysteine (Cys(231)) and arginine (Arg(237)) residues. The structure of LppA at 1.4 Å resolution revealed a mainly ?-helical globular protein stabilized by four antiparallel ?-sheets that binds two phosphate moieties. The phosphates localize to a P-loop active site characteristic of dual specificity phosphatases or to a non-catalytic site, respectively. Phytate reversibly abolished growth of L. pneumophila in broth, and growth inhibition was relieved by overproduction of LppA or by metal ion titration. L. pneumophila lacking lppA replicated less efficiently in phytate-loaded Acanthamoeba castellanii or Dictyostelium discoideum, and the intracellular growth defect was complemented by the phytase gene. These findings identify the chelator phytate as an intracellular bacteriostatic component of cell-autonomous host immunity and reveal a T4SS-translocated L. pneumophila phytase that counteracts intracellular bacterial growth restriction by phytate. Thus, bacterial phytases might represent therapeutic targets to combat intracellular pathogens. PMID:25339170

  8. Putatively free-living 'Endomicrobia'- ancestors of the intracellular symbionts of termite gut flagellates?

    PubMed

    Ikeda-Ohtsubo, Wakako; Faivre, Nicolas; Brune, Andreas

    2010-08-01

    Endomicrobia represent a candidate class in the Elusimicrobia phylum (formerly Termite Group 1) and were originally described as obligate intracellular symbionts of gut flagellates in lower termites. However, 16S rRNA gene sequences of Endomicrobia have been detected also in the gut of insects that do not possess such flagellates, e.g. higher termites and cockroaches. When we eliminated the large gut flagellates of Reticulitermes santonensis by feeding a starch diet, we discovered novel lineages of Endomicrobia that were hitherto undetected in normally faunated specimens. The new phylotypes are clearly separated from the endosymbionts of gut flagellates and fall into the radiation of those from flagellate-free insects. Comprehensive phylogenetic analysis documented that Endomicrobia comprise an apical cluster of endosymbionts that is not necessarily monophyletic and several apparently basal lineages that include bacteria present in the gut of defaunated lower termites, the naturally flagellate-free guts of higher termites and scarab beetle larvae, and in the cow rumen. We propose that these lineages represent hitherto undetected free-living Endomicrobia that share a common ancestor with the intracellular symbionts. PMID:23766225

  9. Chlamydia trachomatis-induced alterations in the host cell proteome are required for intracellular growth

    PubMed Central

    Olive, Andrew J.; Haff, Madeleine G.; Emanuele, Michael J.; Sack, Laura M.; Barker, Jeffrey R.; Elledge, Stephen J.; Starnbach, Michael N.

    2014-01-01

    Summary Intracellular pathogens directly alter host cells in order to replicate and survive. While infection-induced changes in host transcription can be readily assessed, post-transcriptional alterations are more difficult to catalog. We applied the global protein stability (GPS) platform, which assesses protein stability based on relative changes in an adjoining fluorescent tag, to identify changes in the host proteome following infection with the obligate intracellular bacteria Chlamydia trachomatis. Our results indicate that C. trachomatis profoundly remodels the host proteome independently of changes in transcription. Additionally, C. trachomatis replication depends on a subset of altered proteins, such as Pin1 and Men1, which regulate the host transcription factor AP-1 controlling host inflammation, stress, and cell survival. Furthermore, AP-1-dependent transcription is activated during infection, and required for efficient Chlamydia growth. In summary, this experimental approach revealed that C. trachomatis broadly alters host proteins and can be applied to examine host-pathogen interactions and develop host-based therapeutics. PMID:24439903

  10. Genome Sequence of Rickettsia bellii Illuminates the Role of Amoebae in Gene Exchanges between Intracellular Pathogens

    PubMed Central

    Ogata, Hiroyuki; La Scola, Bernard; Audic, Stéphane; Renesto, Patricia; Blanc, Guillaume; Robert, Catherine; Fournier, Pierre-Edouard; Claverie, Jean-Michel; Raoult, Didier

    2006-01-01

    The recently sequenced Rickettsia felis genome revealed an unexpected plasmid carrying several genes usually associated with DNA transfer, suggesting that ancestral rickettsiae might have been endowed with a conjugation apparatus. Here we present the genome sequence of Rickettsia bellii, the earliest diverging species of known rickettsiae. The 1,552,076 base pair–long chromosome does not exhibit the colinearity observed between other rickettsia genomes, and encodes a complete set of putative conjugal DNA transfer genes most similar to homologues found in Protochlamydia amoebophila UWE25, an obligate symbiont of amoebae. The genome exhibits many other genes highly similar to homologues in intracellular bacteria of amoebae. We sought and observed sex pili-like cell surface appendages for R. bellii. We also found that R. bellii very efficiently multiplies in the nucleus of eukaryotic cells and survives in the phagocytic amoeba, Acanthamoeba polyphaga. These results suggest that amoeba-like ancestral protozoa could have served as a genetic “melting pot” where the ancestors of rickettsiae and other bacteria promiscuously exchanged genes, eventually leading to their adaptation to the intracellular lifestyle within eukaryotic cells. PMID:16703114

  11. Gene expression profiles and intracellular contents of stress protectants in Saccharomyces cerevisiae under ethanol and sorbitol stresses

    Microsoft Academic Search

    Tomohiro Kaino; Hiroshi Takagi

    2008-01-01

    In response to osmotic stress, proline is accumulated in many bacterial and plant cells. During various stresses, the yeast\\u000a Saccharomyces cerevisiae induces glycerol or trehalose synthesis, but the fluctuations in gene expression and intracellular levels of proline in yeast\\u000a are not yet well understood. We previously found that proline protects yeast cells from damage by freezing, oxidative, or\\u000a ethanol stress.

  12. 12 CFR 201.108 - Obligations eligible as collateral for advances.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...urban renewal or public housing agencies fully supported...to section 302 of the Housing Act of 1961 (42 U...insured by the Federal Housing Administration are...obligations as collateral for advances, but the Reserve Bank...revenues earmarked for payment of such obligations...

  13. Measuring the Progressive Realization of Human Rights Obligations: An Index of Economic and Social Rights Fulfillment

    Microsoft Academic Search

    Sakiko Fukuda-Parr; Terra Lawson-Remer; Susan Randolph

    2008-01-01

    In response to an increasing demand for rigorous monitoring of state accountability in meeting their human rights obligations, a growing literature on human rights measurement has emerged. Yet there are no widely used indicators or indices of human rights obligations fulfillment. This paper proposes a methodology for an index of economic and social rights fulfillment that: uses available survey-based objective,

  14. The Lived Experience of How Adult Nursing Students Blend Lifestyle Obligations with Nursing School Expectations

    ERIC Educational Resources Information Center

    Coutrier, Karen A.

    2011-01-01

    Many adult nursing students have lifestyle obligations that require integration with nursing school programs in order to graduate and fulfill their dreams of becoming a nurse. Fourteen participants shared their stories of how they were able to blend their lifestyles commitments with nursing school. Student interaction between lifestyle obligations

  15. The Role of Family Obligations and School Adjustment in Explaining the Immigrant Paradox

    ERIC Educational Resources Information Center

    van Geel, Mitch; Vedder, Paul

    2011-01-01

    This study examined the role of family obligations and school adjustment in explaining immigrant adolescents' adaptation. Despite a relatively low socio-economic status, immigrant adolescents have been found to have a pattern of adaptation superior to that of national adolescents. Immigrant adolescents' strong sense of family obligations and…

  16. 28 CFR 43.2 - Obligations of persons receiving care and treatment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Obligations of persons receiving care and treatment. 43.2 Section 43.2 Judicial...COST OF HOSPITAL AND MEDICAL CARE AND TREATMENT FURNISHED BY THE UNITED STATES § 43...Obligations of persons receiving care and treatment. (a) In the discretion of the...

  17. 28 CFR 43.2 - Obligations of persons receiving care and treatment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Obligations of persons receiving care and treatment. 43.2 Section 43.2 Judicial...COST OF HOSPITAL AND MEDICAL CARE AND TREATMENT FURNISHED BY THE UNITED STATES § 43...Obligations of persons receiving care and treatment. (a) In the discretion of the...

  18. 28 CFR 43.2 - Obligations of persons receiving care and treatment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Obligations of persons receiving care and treatment. 43.2 Section 43.2 Judicial...COST OF HOSPITAL AND MEDICAL CARE AND TREATMENT FURNISHED BY THE UNITED STATES § 43...Obligations of persons receiving care and treatment. (a) In the discretion of the...

  19. 28 CFR 43.2 - Obligations of persons receiving care and treatment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Obligations of persons receiving care and treatment. 43.2 Section 43.2 Judicial...COST OF HOSPITAL AND MEDICAL CARE AND TREATMENT FURNISHED BY THE UNITED STATES § 43...Obligations of persons receiving care and treatment. (a) In the discretion of the...

  20. 28 CFR 43.2 - Obligations of persons receiving care and treatment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Obligations of persons receiving care and treatment. 43.2 Section 43.2 Judicial...COST OF HOSPITAL AND MEDICAL CARE AND TREATMENT FURNISHED BY THE UNITED STATES § 43...Obligations of persons receiving care and treatment. (a) In the discretion of the...

  1. Newcomer Psychological Contracts and Employee Socialization Activities: Does Perceived Balance in Obligations Matter?

    ERIC Educational Resources Information Center

    Payne, Stephanie C.; Culbertson, Satoris S.; Boswell, Wendy R.; Barger, Eric J.

    2008-01-01

    We sought to determine the extent to which one's beliefs about the relationship between an employee and an organization at the start of employment influence subsequent socialization activities. The balance of employee exchange relationships, employee perceptions of both their own obligations and the employers' obligations, were collected from 120…

  2. Conceptualising Hy-Bivalent Subjectivities to Facilitate an Examination of Australian Government Mutual Obligations Policies

    ERIC Educational Resources Information Center

    Edwards, Jan

    2006-01-01

    This paper illustrates how the work of feminist theorists Valerie Walkerdine, Helen Lucey and June Melody, Beverly Skeggs, and Nancy Fraser were used together to examine the lived effects of Australian government Mutual Obligations policies. As "active" welfare policies, Mutual Obligations construct particular relations between themselves and…

  3. 26 CFR 1.691(e)-1 - Installment obligations transmitted at death when prior law applied.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...for obligations transmitted at death, but contains no requirement...transmitted, the date of his death, and the internal revenue district...the election is made under the penalties of perjury. (2) Filing...obligation was transmitted at A's death to B who filed a...

  4. 26 CFR 1.691(e)-1 - Installment obligations transmitted at death when prior law applied.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...for obligations transmitted at death, but contains no requirement...transmitted, the date of his death, and the internal revenue district...the election is made under the penalties of perjury. (2) Filing...obligation was transmitted at A's death to B who filed a...

  5. 26 CFR 1.691(e)-1 - Installment obligations transmitted at death when prior law applied.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...for obligations transmitted at death, but contains no requirement...transmitted, the date of his death, and the internal revenue district...the election is made under the penalties of perjury. (2) Filing...obligation was transmitted at A's death to B who filed a...

  6. 26 CFR 1.691(e)-1 - Installment obligations transmitted at death when prior law applied.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...for obligations transmitted at death, but contains no requirement...transmitted, the date of his death, and the internal revenue district...the election is made under the penalties of perjury. (2) Filing...obligation was transmitted at A's death to B who filed a...

  7. 26 CFR 1.691(e)-1 - Installment obligations transmitted at death when prior law applied.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...for obligations transmitted at death, but contains no requirement...transmitted, the date of his death, and the internal revenue district...the election is made under the penalties of perjury. (2) Filing...obligation was transmitted at A's death to B who filed a...

  8. 26 CFR 1.453-9 - Gain or loss on disposition of installment obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...20,000, 50 percent. Face value of notes 15,000 ...of obligation—excess of face value of notes over amount of...of obligation—excess of face value of notes over amount...provides for exceptions to the recognition of gain or loss in...

  9. 26 CFR 1.453-9 - Gain or loss on disposition of installment obligations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...20,000, 50 percent. Face value of notes 15,000 ...of obligation—excess of face value of notes over amount of...of obligation—excess of face value of notes over amount...provides for exceptions to the recognition of gain or loss in...

  10. 26 CFR 1.453-9 - Gain or loss on disposition of installment obligations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...20,000, 50 percent. Face value of notes 15,000 ...of obligation—excess of face value of notes over amount of...of obligation—excess of face value of notes over amount...provides for exceptions to the recognition of gain or loss in...

  11. 26 CFR 1.453-9 - Gain or loss on disposition of installment obligations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...20,000, 50 percent. Face value of notes 15,000 ...of obligation—excess of face value of notes over amount of...of obligation—excess of face value of notes over amount...provides for exceptions to the recognition of gain or loss in...

  12. 26 CFR 1.453-9 - Gain or loss on disposition of installment obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...20,000, 50 percent. Face value of notes 15,000 ...of obligation—excess of face value of notes over amount of...of obligation—excess of face value of notes over amount...provides for exceptions to the recognition of gain or loss in...

  13. Mutual obligation, shared responsibility agreements & indigenous health strategy

    PubMed Central

    Anderson, Ian PS

    2006-01-01

    Since 2004 the Howard Coalition government has implemented a new policy framework and administrative arrangements as part of its program of reform in Indigenous affairs. In this paper I will describe both the parameters of this reform program and review the processes established to support the implementation of national Indigenous health strategy. In particular, I will consider both the shift from a policy framework based on 'self-determination' to one based on 'mutual obligation', and the implementation of Shared Responsibility Agreements (SRAs) that are based on the latter principle. I will use the example of the Mulan SRA to illustrate the difficulties in articulating the 'new arrangements' with current approaches to Indigenous health planning and strategy implementation. I conclude that 'new arrangements' pose a number of problems for Indigenous health planning and strategy that need to be addressed. PMID:16999873

  14. Mutual obligation, shared responsibility agreements & indigenous health strategy.

    PubMed

    Anderson, Ian P S

    2006-01-01

    Since 2004 the Howard Coalition government has implemented a new policy framework and administrative arrangements as part of its program of reform in Indigenous affairs. In this paper I will describe both the parameters of this reform program and review the processes established to support the implementation of national Indigenous health strategy. In particular, I will consider both the shift from a policy framework based on 'self-determination' to one based on 'mutual obligation', and the implementation of Shared Responsibility Agreements (SRAs) that are based on the latter principle. I will use the example of the Mulan SRA to illustrate the difficulties in articulating the 'new arrangements' with current approaches to Indigenous health planning and strategy implementation. I conclude that 'new arrangements' pose a number of problems for Indigenous health planning and strategy that need to be addressed. PMID:16999873

  15. Identification of Bacterial Populations in Drinking Water Using 16S rRNA-Based Sequence Analyses

    EPA Science Inventory

    Intracellular RNA is rapidly degraded in stressed cells and is more unstable outside of the cell than DNA. As a result, RNA-based methods have been suggested to study the active microbial fraction in environmental matrices. The aim of this study was to identify bacterial populati...

  16. Sequence Conservation and Functional Constraint on Intergenic Spacers in Reduced Genomes of the Obligate Symbiont Buchnera

    PubMed Central

    Degnan, Patrick H.; Ochman, Howard; Moran, Nancy A.

    2011-01-01

    Analyses of genome reduction in obligate bacterial symbionts typically focus on the removal and retention of protein-coding regions, which are subject to ongoing inactivation and deletion. However, these same forces operate on intergenic spacers (IGSs) and affect their contents, maintenance, and rates of evolution. IGSs comprise both non-coding, non-functional regions, including decaying pseudogenes at varying stages of recognizability, as well as functional elements, such as genes for sRNAs and regulatory control elements. The genomes of Buchnera and other small genome symbionts display biased nucleotide compositions and high rates of sequence evolution and contain few recognizable regulatory elements. However, IGS lengths are highly correlated across divergent Buchnera genomes, suggesting the presence of functional elements. To identify functional regions within the IGSs, we sequenced two Buchnera genomes (from aphid species Uroleucon ambrosiae and Acyrthosiphon kondoi) and applied a phylogenetic footprinting approach to alignments of orthologous IGSs from a total of eight Buchnera genomes corresponding to six aphid species. Inclusion of these new genomes allowed comparative analyses at intermediate levels of divergence, enabling the detection of both conserved elements and previously unrecognized pseudogenes. Analyses of these genomes revealed that 232 of 336 IGS alignments over 50 nucleotides in length displayed substantial sequence conservation. Conserved alignment blocks within these IGSs encompassed 88 Shine-Dalgarno sequences, 55 transcriptional terminators, 5 Sigma-32 binding sites, and 12 novel small RNAs. Although pseudogene formation, and thus IGS formation, are ongoing processes in these genomes, a large proportion of intergenic spacers contain functional sequences. PMID:21912528

  17. Sequence conservation and functional constraint on intergenic spacers in reduced genomes of the obligate symbiont Buchnera.

    PubMed

    Degnan, Patrick H; Ochman, Howard; Moran, Nancy A

    2011-09-01

    Analyses of genome reduction in obligate bacterial symbionts typically focus on the removal and retention of protein-coding regions, which are subject to ongoing inactivation and deletion. However, these same forces operate on intergenic spacers (IGSs) and affect their contents, maintenance, and rates of evolution. IGSs comprise both non-coding, non-functional regions, including decaying pseudogenes at varying stages of recognizability, as well as functional elements, such as genes for sRNAs and regulatory control elements. The genomes of Buchnera and other small genome symbionts display biased nucleotide compositions and high rates of sequence evolution and contain few recognizable regulatory elements. However, IGS lengths are highly correlated across divergent Buchnera genomes, suggesting the presence of functional elements. To identify functional regions within the IGSs, we sequenced two Buchnera genomes (from aphid species Uroleucon ambrosiae and Acyrthosiphon kondoi) and applied a phylogenetic footprinting approach to alignments of orthologous IGSs from a total of eight Buchnera genomes corresponding to six aphid species. Inclusion of these new genomes allowed comparative analyses at intermediate levels of divergence, enabling the detection of both conserved elements and previously unrecognized pseudogenes. Analyses of these genomes revealed that 232 of 336 IGS alignments over 50 nucleotides in length displayed substantial sequence conservation. Conserved alignment blocks within these IGSs encompassed 88 Shine-Dalgarno sequences, 55 transcriptional terminators, 5 Sigma-32 binding sites, and 12 novel small RNAs. Although pseudogene formation, and thus IGS formation, are ongoing processes in these genomes, a large proportion of intergenic spacers contain functional sequences. PMID:21912528

  18. [Characteristic of clinical strains of gram-negative obligate anaerobes].

    PubMed

    Kadzielska, Joanna; Kierzkowska, Marta; Sawicka-Grzelak, Anna; Rokosz, Alicja; ?uczak, Miros?aw

    2007-01-01

    The aim of the study was to assess prevalence and antibiotic susceptibility profiles ofGram-negative strictly anaerobic bacteria isolated from clinical specimens taken from hospitalized patients in 2005-2006. Biochemical identification and antibiotic susceptibility were done in an automated system ATB Expression (bioMerieux sa). From 12262 specimens examined 867 strains of obligate anaerobes were isolated. Gram-negative strictly anaerobic bacteria were cultured in number of 138 strains (15,9%). All cultures were performed on Columbia agar and Schaedler agar media (bioMerieux sa) supplemented with 5% sheep blood and incubated at 37 degrees C for 48-120 h in 85% N2, 10% H2, 5% CO2. Most frequently isolated was Bacteroides spp. (41,3%). For this group beta-lactamase activity was evaluated by using nitrocefin disc test (Cefinase BBL, Becton Dickinson and Co., Cockeysville, MD, USA). Production of ESBLs was detected with the use of two disc diffusion methods: the double-disc synergy test (DDST) according to Jarlier et al. and the diagnostic disc (DD) test according to Appleton. ESBLs were produced by 5,3% strains of Bacteroides spp. For all Bacteroides spp. strains MIC values were determined by gradient diffusion method Etest (AB BIODISK, Sweden). ESBLs and MIC were performed on Wilkins-Chalgren solid medium supplemented with 5% sheep blood (Difco Lab., USA) and all plates were incubated at 35 degrees C for 48 hours in 85% N2, 10% H2, 5% CO2. Most Gram-negative obligate anaerobes isolated from clinical specimens are still susceptible to imipenem (100%), metronidazole (99,3%) and beta-lactam antibiotics with beta-lactamase inhibitors: piperacillin/tazobactam (99,3%), ticarcillin/clavulanate (99.3%), amoxicillin/clavulanate (97.8%). PMID:18416127

  19. Comparative Phylogeography in a Specific and Obligate Pollination Antagonism

    PubMed Central

    Espíndola, Anahí; Alvarez, Nadir

    2011-01-01

    In specific and obligate interactions the nature and abundance of a given species can have important effects on the survival and population dynamics of associated organisms. In a phylogeographic framework, we therefore expect that the fates of organisms interacting specifically are also tightly interrelated. Here we investigate such a scenario by analyzing the genetic structures of species interacting in an obligate plant-insect pollination lure-and-trap antagonism, involving Arum maculatum (Araceae) and its specific psychodid (Diptera) visitors Psychoda phalaenoides and Psycha grisescens. Because the interaction is asymmetric (i.e., only the plant depends on the insect), we expect the genetic structure of the plant to be related with the historical pollinator availability, yielding incongruent phylogeographic patterns between the interacting organisms. Using insect mtDNA sequences and plant AFLP genome fingerprinting, we inferred the large-scale phylogeographies of each species and the distribution of genetic diversities throughout the sampled range, and evaluated the congruence in their respective genetic structures using hierarchical analyses of molecular variances (AMOVA). Because the composition of pollinator species varies in Europe, we also examined its association with the spatial genetic structure of the plant. Our findings indicate that while the plant presents a spatially well-defined genetic structure, this is not the case in the insects. Patterns of genetic diversities also show dissimilar distributions among the three interacting species. Phylogeographic histories of the plant and its pollinating insects are thus not congruent, a result that would indicate that plant and insect lineages do not share the same glacial and postglacial histories. However, the genetic structure of the plant can, at least partially, be explained by the type of pollinators available at a regional scale. Differences in life-history traits of available pollinators might therefore have influenced the genetic structure of the plant, the dependent organism, in this antagonistic interaction. PMID:22216104

  20. An Extended Role-Based Access Control Model for Delegating Obligations

    NASA Astrophysics Data System (ADS)

    Ben-Ghorbel-Talbi, Meriam; Cuppens, Frédéric; Cuppens-Boulahia, Nora; Bouhoula, Adel

    The main aim of access control models is to provide means to simplify the management of the security policy, which is a fastidious and error-prone task. Supporting delegation is considered as an important mean to decentralize the administration and therefore to allow security policy to be more flexible and easier to manipulate. Our main contribution is the proposition of a unified model to the administration and delegation of obligations. Managing such delegations implies more requirements than managing traditional privileges delegation. In fact, delegating obligations may include two interpretations: the delegation of the obligation and the delegation of the responsibility related to this obligation. Therefore, it is important to deal with these two notions separately. Moreover, since delegating an obligation involves the delegation of sanctions, then the consent of the user who receives this delegation may be required in some cases. We address in this paper these requirements and we propose a formalism to deal with them.