Sample records for obligate intracellular bacterial

  1. Advances in Genetic Manipulation of Obligate Intracellular Bacterial Pathogens

    PubMed Central

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

    2011-01-01

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

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

    PubMed Central

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

    1996-01-01

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

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

    E-print Network

    Bordenstein, Seth

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

  4. 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

  5. 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

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

    PubMed Central

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

    2011-01-01

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

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

    PubMed

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

    2015-01-01

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

  8. 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

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

    Microsoft Academic Search

    Dominique Soldati; John C. Boothroyd

    1993-01-01

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

  10. 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

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

    Microsoft Academic Search

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

    2008-01-01

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

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

    PubMed Central

    2013-01-01

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

  13. 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

  14. 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.

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

    PubMed

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

    2015-01-01

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

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

    PubMed Central

    Thompson, Christopher C.; Carabeo, Rey A.

    2011-01-01

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

  17. 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

  18. 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

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

    Microsoft Academic Search

    Wolfgang Eisenreich; Thomas Dandekar; Jürgen Heesemann; Werner Goebel

    2010-01-01

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

  20. 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

  1. 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

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

    SciTech Connect

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

    2006-01-01

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

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

    E-print Network

    Higgins, Darren

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

  4. 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

  5. NK cells activated in vivo by bacterial DNA control the intracellular growth of Francisella tularensis LVS.

    PubMed

    Elkins, Karen L; Colombini, Susan M; Krieg, Arthur M; De Pascalis, Roberto

    2009-01-01

    We demonstrated previously that mice treated with bacterial or oligonucleotide DNA containing unmethylated CpG motifs are transiently protected against lethal parenteral challenge with the intracellular bacterium Francisella tularensis Live Vaccine Strain (LVS). Here we explore the cellular basis of this protection. Wild-type mice that were treated with CpG oligonucleotide DNA and challenged with a lethal dose of LVS survived, while mice lacking TLR9 did not. In vitro, treatment of LVS-infected macrophages and/or naive splenocytes with oligo DNA had no impact on intracellular bacterial replication. In contrast, in vitro co-culture of LVS-infected macrophages with splenocytes obtained from mice treated with oligo DNA in vivo resulted in control of intracellular LVS growth. Control was reversed by antibodies to interferon-gamma or to tumor necrosis factor-alpha and by inhibition of nitric oxide, and to a lesser degree by antibodies to Interleukin-12. Further, splenocytes from DNA-primed normal, T cell KO, B cell KO, lymphocyte-deficient scid, or perforin KO mice all controlled intra-macrophage LVS growth. Enriched DNA-primed natural killer cells, but not B cells, clearly controlled intracellular LVS growth. Thus, NK cells contribute to DNA-mediated protection by production of cytokines including IFN-gamma and TNF-alpha, resulting in nitric oxide production and control of intracellular Francisella replication. PMID:18992838

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

    Microsoft Academic Search

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

    2002-01-01

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

  7. 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

  8. 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

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

    PubMed

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

    2014-01-01

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

  10. Proteomic Analyses of Intracellular Salmonella enterica Serovar Typhimurium Reveal Extensive Bacterial Adaptations to Infected Host Epithelial Cells.

    PubMed

    Liu, Yanhua; Zhang, Qiufeng; Hu, Mo; Yu, Kaiwen; Fu, Jiaqi; Zhou, Fan; Liu, Xiaoyun

    2015-07-01

    Salmonella species can gain access into nonphagocytic cells, where the bacterium proliferates in a unique membrane-bounded compartment. In order to reveal bacterial adaptations to their intracellular niche, here we conducted the first comprehensive proteomic survey of Salmonella isolated from infected epithelial cells. Among ?3,300 identified bacterial proteins, we found that about 100 proteins were significantly altered at the onset of Salmonella intracellular replication. In addition to substantially increased iron-uptake capacities, bacterial high-affinity manganese and zinc transporters were also upregulated, suggesting an overall limitation of metal ions in host epithelial cells. We also found that Salmonella induced multiple phosphate utilization pathways. Furthermore, our data suggested upregulation of the two-component PhoPQ system as well as of many downstream virulence factors under its regulation. Our survey also revealed that intracellular Salmonella has increased needs for certain amino acids and biotin. In contrast, Salmonella downregulated glycerol and maltose utilization as well as chemotaxis pathways. PMID:25939512

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

    PubMed

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

    2013-01-01

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

  12. A metabolic study of Buchnera, the intracellular bacterial symbionts of the pea aphid Acyrthosiphon pisum

    Microsoft Academic Search

    L. F. Whitehead; A. E. Douglas

    1993-01-01

    Cells of the bacterium Buchnera were isolated from embryos of the pea aphid Acyrthosiphon pisum, with an intact perisymbiont membrane (the insect membrane which surrounds each bacterial cell inside the aphid). The bacterial preparations respired aerobically, consuming oxygen at an average rate of 24 nmol (mg protein)-' min-'. The bacteria took up a range of carboxylic acids and the amino

  13. Bacterial Growth Rate and Host Factors as Determinants of Intracellular Bacterial Distributions in Systemic Salmonella enterica Infections?

    PubMed Central

    Grant, Andrew J.; Foster, Gemma L.; McKinley, Trevelyan J.; Brown, Sam P.; Clare, Simon; Maskell, Duncan J.; Mastroeni, Pietro

    2009-01-01

    Bacteria of the species Salmonella enterica cause a range of life-threatening diseases in humans and animals worldwide. The within-host quantitative, spatial, and temporal dynamics of S. enterica interactions are key to understanding how immunity acts on these infections and how bacteria evade immune surveillance. In this study, we test hypotheses generated from mathematical models of in vivo dynamics of Salmonella infections with experimental observation of bacteria at the single-cell level in infected mouse organs to improve our understanding of the dynamic interactions between host and bacterial mechanisms that determine net growth rates of S. enterica within the host. We show that both bacterial and host factors determine the numerical distributions of bacteria within host cells and thus the level of dispersiveness of the infection. PMID:19797065

  14. A census of membrane-bound and intracellular signal transduction proteins in bacteria: Bacterial IQ, extroverts and introverts

    PubMed Central

    Galperin, Michael Y

    2005-01-01

    Background Analysis of complete microbial genomes showed that intracellular parasites and other microorganisms that inhabit stable ecological niches encode relatively primitive signaling systems, whereas environmental microorganisms typically have sophisticated systems of environmental sensing and signal transduction. Results This paper presents results of a comprehensive census of signal transduction proteins – histidine kinases, methyl-accepting chemotaxis receptors, Ser/Thr/Tyr protein kinases, adenylate and diguanylate cyclases and c-di-GMP phosphodiesterases – encoded in 167 bacterial and archaeal genomes, sequenced by the end of 2004. The data have been manually checked to avoid false-negative and false-positive hits that commonly arise during large-scale automated analyses and compared against other available resources. The census data show uneven distribution of most signaling proteins among bacterial and archaeal phyla. The total number of signal transduction proteins grows approximately as a square of genome size. While histidine kinases are found in representatives of all phyla and are distributed according to the power law, other signal transducers are abundant in certain phylogenetic groups but virtually absent in others. Conclusion The complexity of signaling systems differs even among closely related organisms. Still, it usually can be correlated with the phylogenetic position of the organism, its lifestyle, and typical environmental challenges it encounters. The number of encoded signal transducers (or their fraction in the total protein set) can be used as a measure of the organism's ability to adapt to diverse conditions, the 'bacterial IQ', while the ratio of transmembrane receptors to intracellular sensors can be used to define whether the organism is an 'extrovert', actively sensing the environmental parameters, or an 'introvert', more concerned about its internal homeostasis. Some of the microorganisms with the highest IQ, including the current leader Wolinella succinogenes, are found among the poorly studied beta-, delta- and epsilon-proteobacteria. Among all bacterial phyla, only cyanobacteria appear to be true introverts, probably due to their capacity to conduct oxygenic photosynthesis, using a complex system of intracellular membranes. The census data, available at , can be used to get an insight into metabolic and behavioral propensities of each given organism and improve prediction of the organism's properties based solely on its genome sequence. PMID:15955239

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

    Microsoft Academic Search

    Jin Huang; Cammie F. Lesser; Stephen Lory

    2008-01-01

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

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

    PubMed Central

    Okegbe, Chinweike; Price-Whelan, Alexa; Sakhtah, Hassan; Hunter, Ryan C.; Newman, Dianne K.

    2013-01-01

    Many microbial species form multicellular structures comprising elaborate wrinkles and concentric rings, yet the rules governing their architecture are poorly understood. The opportunistic pathogen Pseudomonas aeruginosa produces phenazines, small molecules that act as alternate electron acceptors to oxygen and nitrate to oxidize the intracellular redox state and that influence biofilm morphogenesis. Here, we show that the depth occupied by cells within colony biofilms correlates well with electron acceptor availability. Perturbations in the environmental provision, endogenous production, and utilization of electron acceptors affect colony development in a manner consistent with redox control. Intracellular NADH levels peak before the induction of colony wrinkling. These results suggest that redox imbalance is a major factor driving the morphogenesis of P. aeruginosa biofilms and that wrinkling itself is an adaptation that maximizes oxygen accessibility and thereby supports metabolic homeostasis. This type of redox-driven morphological change is reminiscent of developmental processes that occur in metazoans. PMID:23292774

  17. Free intracellular Ca 2+ regulates bacterial lipopolysaccharide induction of iNOS in human macrophages

    Microsoft Academic Search

    Anthony A. Azenabor; Patrick Kennedy; Jenniffer York

    2009-01-01

    Inducible nitric oxide synthase (iNOS) reaction is of enormous significance in innate immune protective response of host to microbial challenges. We speculate that microbial challenges, by virtue of their lipopolysaccharide (LPS) content, exert an effect on intracellular free Ca2+ levels ([Ca2+]i), which evokes cellular signaling in a manner that depends on LPS type. In this study, we investigated the effect

  18. Modulation of neutrophil superoxide response and intracellular diacylglyceride levels by the bacterial pigment pyocyanin.

    PubMed Central

    Muller, M; Sorrell, T C

    1997-01-01

    Low concentrations of pyocyanin are reported to enhance superoxide production by human neutrophils exposed to various stimuli, yet the mechanism remains unknown. Using lucigenin-enhanced chemiluminescence, we examined the kinetics of the neutrophil superoxide response in the presence of pyocyanin. At all concentrations (12.5 to 200 microM), pyocyanin decreased the peak superoxide response while prolonging the duration of the response. The prolonged response may be associated with an observed increase in intracellular diacylglyceride levels due to pyocyanin exposure. PMID:9169797

  19. Extracellular Superoxide Dismutase Inhibits Innate Immune Responses and Clearance of an Intracellular Bacterial Infection

    PubMed Central

    Break, Timothy J.; Jun, Sujung; Indramohan, Mohanalaxmi; Carr, Karen D.; Sieve, Amy N.; Dory, Ladislav; Berg, Rance E.

    2012-01-01

    Reactive oxygen and nitrogen species (ROS/RNS) play important roles during immune responses to bacterial pathogens. Extracellular superoxide dismutase (ecSOD) regulates extracellular concentrations of ROS/RNS and contributes to tissue protection during inflammatory insults. The participation of ecSOD in immune responses seems therefore intuitive, yet is poorly understood. In the present study, we utilized mice with varying levels of ecSOD activity to investigate the involvement of this enzyme in immune responses against Listeria monocytogenes. Surprisingly, our data demonstrate that, despite enhanced neutrophil recruitment to the liver, ecSOD activity negatively impacted host survival and bacterial clearance. Increased ecSOD activity was accompanied by decreased co-localization of neutrophils with bacteria, as well as increased neutrophil apoptosis, which reduced overall and neutrophil-specific TNF-? production. Liver leukocytes from mice lacking ecSOD produced equivalent nitric oxide (NO·) when compared to mice expressing ecSOD. However, during infection, there were higher levels of peroxynitrite (NO3·?) in livers from mice lacking ecSOD compared to mice expressing ecSOD. Neutrophil depletion studies revealed that high levels of ecSOD activity resulted in neutrophils with limited protective capacity, whereas neutrophils from mice lacking ecSOD provided superior protection compared to neutrophils from wild-type mice. Taken together, our data demonstrate that ecSOD activity reduces innate immune responses during bacterial infection and provides a potential target for therapeutic intervention. PMID:22393157

  20. Inhibition of intracellular bacterial replication in fibroblasts is dependent on the perforin-like protein (Perforin-2) encoded by macrophage expressed gene 1

    PubMed Central

    McCormack, Ryan; de Armas, Lesley R.; Shiratsuchi, Motoaki; Ramos, Jay; Podack, Eckhard R.

    2013-01-01

    Fibroblasts are known to eliminate intracellular bacteria, but the lethal hit of the bactericidal mechanism has not been defined. We show that primary embryonic and established fibroblasts can be induced by interferons or by intracellular bacterial infection to express a perforin-like mRNA previously described as macrophage expressed gene 1 (mpeg1). The presence and level of the perforin-like mRNA correlate with the ability of primary mouse embryonic fibroblasts (MEF) to eliminate intracellular bacteria. In addition, siRNA knock-down of the perforin-like molecule abolishes bactericidal activity and allows intracellular bacterial replication. Complementation of MEF in which the endogenous perforin-like molecule has been knocked down with an RFP-tagged version restores bactericidal activity. The perforin-like molecule has broad bactericidal specificity for pathogenic and non-pathogenic bacteria including Gram positive, Gram negative and acid fast bacteria. The perforin-like molecule renders previously lysozyme-resistant bacteria sensitive to lysis by lysozyme suggesting physical damage of the outer cell wall by the perforin-like protein. MEFs damage cell walls of intracellular bacteria by insertion, polymerization and pore-formation of the perforin-like protein, analogous to pore-formers of complement and Perforin-1 of cytolytic lymphocytes. We propose the name Perforin-2. PMID:23257510

  1. Inhibition of intracellular bacterial replication in fibroblasts is dependent on the perforin-like protein (perforin-2) encoded by macrophage-expressed gene 1.

    PubMed

    McCormack, Ryan; de Armas, Lesley R; Shiratsuchi, Motoaki; Ramos, Jahir E; Podack, Eckhard R

    2013-01-01

    Fibroblasts are known to eliminate intracellular bacteria, but the lethal hit of the bactericidal mechanism has not been defined. We show that primary embryonic and established fibroblasts can be induced by interferons or by intracellular bacterial infection to express a perforin-like mRNA previously described as macrophage-expressed gene 1 (Mpeg1). The presence and level of the perforin-like mRNA correlate with the ability of primary mouse embryonic fibroblasts (MEF) to eliminate intracellular bacteria. In addition, siRNA knockdown of the perforin-like molecule abolishes bactericidal activity and allows intracellular bacterial replication. Complementation of MEF in which the endogenous perforin-like molecule has been knocked down with a red fluorescent protein-tagged version restores bactericidal activity. The perforin-like molecule has broad bactericidal specificity for pathogenic and non-pathogenic bacteria, including Gram-positive and -negative, and acid fast bacteria. The perforin-like molecule renders previously lysozyme-resistant bacteria sensitive to lysis by lysozyme suggesting physical damage of the outer cell wall by the perforin-like protein. MEF damage cell walls of intracellular bacteria by insertion, polymerization, and pore formation of the perforin-like protein, analogous to pore formers of complement and perforin-1 of cytolytic lymphocytes. We propose the name perforin-2. PMID:23257510

  2. Free intracellular Ca2+ regulates bacterial lipopolysaccharide induction of iNOS in human macrophages.

    PubMed

    Azenabor, Anthony A; Kennedy, Patrick; York, Jenniffer

    2009-01-01

    Inducible nitric oxide synthase (iNOS) reaction is of enormous significance in innate immune protective response of host to microbial challenges. We speculate that microbial challenges, by virtue of their lipopolysaccharide (LPS) content, exert an effect on intracellular free Ca(2+) levels ([Ca(2+)]i), which evokes cellular signaling in a manner that depends on LPS type. In this study, we investigated the effect of LPS from heterogeneous sources (Chlamydia pneumoniae [cLPS], Pseudomonas aeruginosa [pLPS], and Salmonella typhimurium [sLPS]) on nitric oxide (NO) release and iNOS expression in THP-1- and U937-derived macrophages, and determined the role of free [Ca(2+)]i on LPS-mediated generation of NO and iNOS expression in these cell types. The role of free [Ca(2+)]i oscillation and the probable input of extracellular Ca(2+) influx on Ca(2+)-signals was monitored in relation to iNOS expression in LPS-stimulated macrophages. There was a significant difference in the time course release of NO in both macrophage types when stimulated with cLPS, or pLPS, or sLPS. In all instances, LPS induced a significant release of NO compared with interferon-gamma. There was a difference in the pattern of basal iNOS reaction leading to NO release compared to iNOS expression observed at 24h post-stimulation. While a biphasic pattern was observed in the manner in which free [Ca(2+)]i affected iNOS expression, inhibition of extracellular Ca(2+) influx resulted in a steady increase in iNOS expression. The implications of these findings are: moderate free [Ca(2+)]i affects macrophage release of NO and iNOS expression during LPS stimulation; also, LPS of heterogeneous sources differentially evokes macrophage iNOS reactions irrespective of macrophage types. PMID:19167993

  3. 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

  4. Applying an Inducible Expression System to Study Interference of Bacterial Virulence Factors with Intracellular Signaling.

    PubMed

    Berens, Christian; Bisle, Stephanie; Klingenbeck, Leonie; Lührmann, Anja

    2015-01-01

    The technique presented here allows one to analyze at which step a target protein, or alternatively a small molecule, interacts with the components of a signaling pathway. The method is based, on the one hand, on the inducible expression of a specific protein to initiate a signaling event at a defined and predetermined step in the selected signaling cascade. Concomitant expression, on the other hand, of the gene of interest then allows the investigator to evaluate if the activity of the expressed target protein is located upstream or downstream of the initiated signaling event, depending on the readout of the signaling pathway that is obtained. Here, the apoptotic cascade was selected as a defined signaling pathway to demonstrate protocol functionality. Pathogenic bacteria, such as Coxiella burnetii, translocate effector proteins that interfere with host cell death induction in the host cell to ensure bacterial survival in the cell and to promote their dissemination in the organism. The C. burnetii effector protein CaeB effectively inhibits host cell death after induction of apoptosis with UV-light or with staurosporine. To narrow down at which step CaeB interferes with the propagation of the apoptotic signal, selected proteins with well-characterized pro-apoptotic activity were expressed transiently in a doxycycline-inducible manner. If CaeB acts upstream of these proteins, apoptosis will proceed unhindered. If CaeB acts downstream, cell death will be inhibited. The test proteins selected were Bax, which acts at the level of the mitochondria, and caspase 3, which is the major executioner protease. CaeB interferes with cell death induced by Bax expression, but not by caspase 3 expression. CaeB, thus, interacts with the apoptotic cascade between these two proteins. PMID:26168006

  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. 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 ...

  7. 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

  8. Complete Bacteriophage Transfer in a Bacterial Endosymbiont (Wolbachia) Determined by Targeted Genome Capture

    PubMed Central

    Kent, Bethany N.; Salichos, Leonidas; Gibbons, John G.; Rokas, Antonis; Newton, Irene L. G.; Clark, Michael E.; Bordenstein, Seth R.

    2011-01-01

    Bacteriophage flux can cause the majority of genetic diversity in free-living bacteria. This tenet of bacterial genome evolution generally does not extend to obligate intracellular bacteria owing to their reduced contact with other microbes and a predominance of gene deletion over gene transfer. However, recent studies suggest intracellular coinfections in the same host can facilitate exchange of mobile elements between obligate intracellular bacteria—a means by which these bacteria can partially mitigate the reductive forces of the intracellular lifestyle. To test whether bacteriophages transfer as single genes or larger regions between coinfections, we sequenced the genome of the obligate intracellular Wolbachia strain wVitB from the parasitic wasp Nasonia vitripennis and compared it against the prophage sequences of the divergent wVitA coinfection. We applied, for the first time, a targeted sequence capture array to specifically trap the symbiont's DNA from a heterogeneous mixture of eukaryotic, bacterial, and viral DNA. The tiled array successfully captured the genome with 98.3% efficiency. Examination of the genome sequence revealed the largest transfer of bacteriophage and flanking genes (52.2 kb) to date between two obligate intracellular coinfections. The mobile element transfer occurred in the recent evolutionary past based on the 99.9% average nucleotide identity of the phage sequences between the two strains. In addition to discovering an evolutionary recent and large-scale horizontal phage transfer between coinfecting obligate intracellular bacteria, we demonstrate that “targeted genome capture” can enrich target DNA to alleviate the problem of isolating symbiotic microbes that are difficult to culture or purify from the conglomerate of organisms inside eukaryotes. PMID:21292630

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

    PubMed

    Early, Julie; Bermudez, Luiz E

    2011-06-01

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

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

    Microsoft Academic Search

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

    2005-01-01

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

  11. Intracellular proteoglycans.

    PubMed Central

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

    2004-01-01

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

  12. Transposon Mutagenesis of the Obligate Intracellular Pathogen Rickettsia prowazekii

    Microsoft Academic Search

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

    2004-01-01

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

  13. Innate recognition of intracellular bacteria.

    PubMed

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

    2007-02-01

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

  14. Functional genomics of intracellular bacteria.

    PubMed

    de Barsy, Marie; Greub, Gilbert

    2013-07-01

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

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

    PubMed Central

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

    2012-01-01

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

  16. Coxiella burnetii: host and bacterial responses to infection.

    PubMed

    Waag, David M

    2007-10-16

    Designation as a Category B biothreat agent has propelled Coxiella burnetii from a relatively obscure, underappreciated, "niche" microorganism on the periphery of bacteriology, to one of possibly great consequence if actually used in acts of bioterrorism. Advances in the study of this microorganism proceeded slowly, primarily because of the difficulty in studying this obligate intracellular pathogen that must be manipulated under biosafety level-3 conditions. The dogged determination of past and current C. burnetii researchers and the application of modern immunological and molecular techniques have more clearly defined the host and bacterial response to infection. This review is intended to provide a basic introduction to C. burnetii and Q fever, while emphasizing immunomodulatory properties, both positive and negative, of Q fever vaccines and C. burnetii infections. PMID:17825460

  17. [Intracellular accumulation of monomer precursors of polyphosphates and polyhydroxyalkanoates from Acinetobacter calcoaceticus and Escherichia coli].

    PubMed

    Saralov, A I; Mol'kov, D V; Bannikova, O M; Solomenny?, A P; Chikin, S M

    2001-01-01

    The formation of polyhydroxyalkanoates granules in anaerobically grown Escherichia coli cells was found to be preceded by the intracellular accumulation of carbonic acids (predominantly, acetic acid), amounting to 9% of the cytosol. The intracellular concentration of acidic metabolites increased after the lyophilization of the bacterial biomass and decreased after its long-term storage (3.5-13.5 years). The decrease in the concentration of acidic metabolites is likely due to the dehydration of dimeric carbonic acids in the viscoelastic cytosol of resting bacterial cells. The hydrophobic obligately aerobic cells of Acinetobacter calcoaceticus IEGM 549 are able to utilize a wide range of growth substrates (from acetate and citrate to hydrophobic hydrocarbons), which is considerably wider than the range of the growth substrates of E. coli (predominantly, carbohydrates). The minimal essential and optimal concentrations of orthophosphates in the growth medium of A. calcoaceticus were found to be tens of times lower than in the case of E. coli. The intracellular content of orthophosphates in A. calcoaceticus cells reached 35-77% of the total phosphorus content (Ptotal), providing for the intense synthesis of polyphosphates. The Ptotal of the A. calcoaceticus cells grown in media with different proportions between the concentrations of acetate and phosphorus varied from 0.7 to 3.3%, averaging 2%. This value of Ptotal is about two times higher than that observed for fermenting E. coli cells. Lowering the cultivation temperature of A. calcoaceticus from 37-32 to 4 degrees C augmented the accumulation of orthophosphates in the cytoplasm, presumably owing to a decreased requirement of growth processes for orthophosphate. In this case, if the concentration of phosphates in the cultivation medium was low, they were completely depleted. PMID:11785129

  18. Obligately barophilic bacterium from the Mariana trench.

    PubMed

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

    1981-08-01

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

  19. Trimethylamine metabolism in obligate and facultative methylotrophs

    PubMed Central

    Colby, J.; Zatman, L. J.

    1973-01-01

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

  20. 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

  1. Evolution of signal transduction in intracellular symbiosis

    Microsoft Academic Search

    Catherine Kistner; Martin Parniske

    2002-01-01

    Plant roots form intracellular symbioses with fungi and bacteria resulting in arbuscular mycorrhiza and nitrogen-fixing root nodules, respectively. A novel receptor like-kinase has been discovered that is required for the transduction of both bacterial and fungal symbiotic signals. This kinase defines an ancient signalling pathway that probably evolved in the context of arbuscular mycorrhiza and has been recruited subsequently for

  2. 12 CFR 987.10 - Obligations of United States with respect to consolidated obligations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  3. 1 Lipopolysaccharide Neutralizing Peptide-Porphyrin Conjugates for 2 Effective Photoinactivation and Intracellular Imaging of Gram-

    E-print Network

    Xing, Bengang

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

  4. 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

  5. 17 CFR 200.54 - Constitutional obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  6. 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...

  7. 42 CFR 136.332 - Service obligation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  8. 42 CFR 136.332 - Service obligation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  9. 42 CFR 136.332 - Service obligation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  10. 42 CFR 136.332 - Service obligation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  11. 42 CFR 136.332 - Service obligation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  12. 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

  13. 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

  14. Strategies for Intracellular Survival of Burkholderia pseudomallei

    PubMed Central

    Allwood, Elizabeth M.; Devenish, Rodney J.; Prescott, Mark; Adler, Ben; Boyce, John D.

    2011-01-01

    Burkholderia pseudomallei is the causative agent of melioidosis, a disease with high mortality that is prevalent in tropical regions of the world. A key component of the pathogenesis of melioidosis is the ability of B. pseudomallei to enter, survive, and replicate within mammalian host cells. For non-phagocytic cells, bacterial adhesins have been identified both on the bacterial surface and associated with Type 4 pili. Cell invasion involves components of one or more of the three Type 3 Secretion System clusters, which also mediate, at least in part, the escape of bacteria from the endosome into the cytoplasm, where bacteria move by actin-based motility. The mechanism of actin-based motility is not clearly understood, but appears to differ from characterized mechanisms in other bacterial species. A small proportion of intracellular bacteria is targeted by host cell autophagy, involving direct recruitment of LC3 to endosomes rather than through uptake by canonical autophagosomes. However, the majority of bacterial cells are able to circumvent autophagy and other intracellular defense mechanisms such as the induction of inducible nitric oxide synthase, and then replicate in the cytoplasm and spread to adjacent cells via membrane fusion, resulting in the formation of multi-nucleated giant cells. A potential role for host cell ubiquitin in the autophagic response to bacterial infection has recently been proposed. PMID:22007185

  15. Natural Functions of Bacterial Polyhydroxyalkanoates

    Microsoft Academic Search

    Susana Castro-Sowinski; Saul Burdman; Ofra Matan; Yaacov Okon

    \\u000a Polyhydroxyalkanoates (PHAs) are energy- and intracellular carbon-storage compounds that can be mobilized and used when carbon\\u000a is a limiting resource. Intracellular accumulation of PHA enhances the survival of several bacterial species under environmental\\u000a stress conditions imposed in water and soil, such as UV irradiation, salinity, thermal and oxidative stress, desiccation,\\u000a and osmotic shock. The ability to endure these stresses is

  16. The role of autophagy in intracellular pathogen nutrient acquisition

    PubMed Central

    Steele, Shaun; Brunton, Jason; Kawula, Thomas

    2015-01-01

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

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

    Microsoft Academic Search

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

    2008-01-01

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

  18. 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.

  19. Bacterial computing with engineered populations.

    PubMed

    Amos, Martyn; Axmann, Ilka Maria; Blüthgen, Nils; de la Cruz, Fernando; Jaramillo, Alfonso; Rodriguez-Paton, Alfonso; Simmel, Friedrich

    2015-07-28

    We describe strategies for the construction of bacterial computing platforms by describing a number of results from the recently completed bacterial computing with engineered populations project. In general, the implementation of such systems requires a framework containing various components such as intracellular circuits, single cell input/output and cell-cell interfacing, as well as extensive analysis. In this overview paper, we describe our approach to each of these, and suggest possible areas for future research. PMID:26078340

  20. 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

  1. 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

  2. Toward Intracellular Targeted Delivery of Cancer Therapeutics

    PubMed Central

    Pandya, Hetal; Debinski, Waldemar

    2013-01-01

    A number of anti-cancer drugs have their targets localized to particular intracellular compartments. These drugs reach the targets mainly through diffusion, dependent on biophysical and biochemical forces that allow cell penetration. This means that both cancer cells and normal cells will be subjected to such diffusion; hence many of these drugs, like chemotherapeutics, are potentially toxic and the concentration achieved at the site of their action is often suboptimal. The same relates to radiation that indiscriminately affects normal and diseased cells. However, nature-designed systems enable compounds present in the extracellular environment to end up inside the cell and even travel to more specific intracellular compartments. For example, viruses and bacterial toxins can more or less specifically recognize eukaryotic cells, enter these cells, and direct some protein portions to designated intracellular areas. These phenomena have led to creative thinking, such as employing viruses or bacterial toxins for cargo delivery to cells and, more specifically, to cancer cells. Proteins can be genetically engineered in order to not only mimic what viruses and bacterial toxins can do, but also to add new functions, extending or changing the intracellular routes. It is possible to make conjugates or, more preferably, single-chain proteins that recognize cancer cells and deliver cargo inside the cells, even to the desired subcellular compartment. These findings offer new opportunities to deliver drugs/labels only to cancer cells and only to their site of action within the cells. The development of such dual-specificity vectors for targeting cancer cells is an attractive and potentially safer and more efficacious way of delivering drugs. We provide examples of this approach for delivering brain cancer therapeutics, using a specific biomarker on glioblastoma tumor cells. PMID:22671766

  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. Collateralized Debt Obligations and Credit Risk Transfer

    Microsoft Academic Search

    Douglas Lucas; Laurie Goodman; Frank Fabozzi

    2007-01-01

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

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 18 CFR 292.313 - Reinstatement of obligation to sell.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  11. 18 CFR 292.311 - Reinstatement of obligation to purchase.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

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

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

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

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

  14. 7 CFR 1488.12 - Coverage of bank obligations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  15. 7 CFR 1488.12 - Coverage of bank obligations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  16. 7 CFR 1488.12 - Coverage of bank obligations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  17. 7 CFR 1488.12 - Coverage of bank obligations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  18. 7 CFR 1488.12 - Coverage of bank obligations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

  19. 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

  20. 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

  1. 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...

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

    Microsoft Academic Search

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

    2003-01-01

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

  3. 40 CFR 1043.30 - General obligations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  4. 40 CFR 1043.30 - General obligations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  5. 40 CFR 1043.30 - General obligations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  6. 40 CFR 1043.30 - General obligations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  7. 40 CFR 1043.30 - General obligations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  8. 19 CFR 10.2005 - Importer obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  9. 5 CFR 352.908 - Agency obligation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  10. 5 CFR 352.908 - Agency obligation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  11. 5 CFR 352.908 - Agency obligation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

  12. 19 CFR 10.905 - Importer obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  13. 19 CFR 10.905 - Importer obligations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  14. 19 CFR 10.905 - Importer obligations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  15. 5 CFR 352.908 - Agency obligation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  16. 5 CFR 352.908 - Agency obligation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  17. Naval Engineering A National Naval Obligation

    E-print Network

    Chryssostomidis, Chryssostomos

    2000-05-16

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

  18. 19 CFR 10.849 - Importer obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  19. 19 CFR 10.849 - Importer obligations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  20. 19 CFR 10.849 - Importer obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  1. 19 CFR 10.849 - Importer obligations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

  2. 19 CFR 10.849 - Importer obligations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  3. Risk and Valuation of Collateralized Debt Obligations

    Microsoft Academic Search

    Darrell Duffie; Nicolae Gârleanu

    2001-01-01

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

  4. 46 CFR Sec. 11 - Guarantee obligations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  5. 46 CFR Sec. 11 - Guarantee obligations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  6. 46 CFR Sec. 11 - Guarantee obligations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  7. 46 CFR Sec. 11 - Guarantee obligations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  8. 46 CFR Sec. 11 - Guarantee obligations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  9. 19 CFR 10.3005 - Importer obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  10. 19 CFR 10.3005 - Importer obligations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  11. Biochemical Stratagem for Obligate Parasitism of Eukaryotic Cells by Coxiella burnetii

    Microsoft Academic Search

    Ted Hackstadt; Jim C. Williams

    1981-01-01

    Coxiella burnetti, the etiologic agent of Q fever, is an oligate intracellular parasite of eukaryotes. Unlike the majority of successful bacterial parasites, which escape the bactericidal environment of the phagolysosome by various means, C. burnetii multiplies only in the phagolysosome. In view of the relatively harsh environment inhabited by C. burnetii, we have examined (i) the in vitro metabolism of

  12. Cell Biology Intracellular Transport

    E-print Network

    Schüler, Axel

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

  13. 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

  14. 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.

  15. 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

  16. Experimental evolution of nodule intracellular infection in legume symbionts

    PubMed Central

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

    2013-01-01

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

  17. 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)

  18. Bacterial Vaginosis

    MedlinePLUS

    ... Funding About NIAID News & Events NIAID > Health & Research Topics > Bacterial Vaginosis Skip Website Tools Website Tools Print this page Order publications Volunteer for Clinical Studies Help people ...

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

    PubMed Central

    Nguyen, Bidong D.; Valdivia, Raphael H.

    2012-01-01

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

  20. 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

  1. 31 CFR 1021.311 - Filing obligations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  2. 31 CFR 1021.311 - Filing obligations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  3. 31 CFR 1021.311 - Filing obligations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  4. 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...

  5. Fetal Diagnosis – Obligations of the Clinician

    Microsoft Academic Search

    Samuel Menahem; Lynn Gillam

    2007-01-01

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

  6. 24 CFR 582.410 - Obligation and deobligation of funds.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

  7. 24 CFR 582.410 - Obligation and deobligation of funds.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  8. 24 CFR 582.410 - Obligation and deobligation of funds.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  9. 24 CFR 582.410 - Obligation and deobligation of funds.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  10. 24 CFR 582.410 - Obligation and deobligation of funds.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  11. 47 CFR 22.878 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  12. 47 CFR 22.971 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  13. 47 CFR 22.878 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  14. 47 CFR 22.878 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  15. 47 CFR 22.971 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  16. 47 CFR 22.971 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  17. 47 CFR 22.878 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  18. 47 CFR 22.971 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  19. 47 CFR 22.971 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  20. 47 CFR 22.878 - Obligation to abate unacceptable interference.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  1. 29 CFR 500.100 - Vehicle safety obligations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  2. 29 CFR 500.100 - Vehicle safety obligations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  3. 47 CFR 76.56 - Signal carriage obligations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  4. 47 CFR 76.56 - Signal carriage obligations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  5. 47 CFR 76.56 - Signal carriage obligations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  6. 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...

  7. 12 CFR 966.2 - Issuance of consolidated obligations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 29 CFR 500.100 - Vehicle safety obligations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  13. 13 CFR 500.213 - Termination of obligations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  14. 16 CFR 436.2 - Obligation to furnish documents.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  15. 34 CFR 685.212 - Discharge of a loan obligation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  16. 34 CFR 685.212 - Discharge of a loan obligation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  17. 34 CFR 685.212 - Discharge of a loan obligation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  18. 34 CFR 685.212 - Discharge of a loan obligation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  19. 43 CFR 3162.2-1 - Drilling and producing obligations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  20. 25 CFR 226.9 - Rental and drilling obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  2. 25 CFR 226.9 - Rental and drilling obligations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

  3. 25 CFR 226.9 - Rental and drilling obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  4. 43 CFR 3162.2-1 - Drilling and producing obligations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  5. 43 CFR 3162.2-1 - Drilling and producing obligations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  6. 25 CFR 226.9 - Rental and drilling obligations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  7. 25 CFR 226.9 - Rental and drilling obligations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  8. 12 CFR 560.42 - State and local government obligations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

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

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

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

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

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

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

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

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  13. 12 CFR 160.42 - State and local government obligations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. Palatal Actinomycosis and Kaposi Sarcoma in an HIV-Infected Subject with Disseminated Mycobacterium avium-intracellulare Infection

    PubMed Central

    Ablanedo-Terrazas, Yuria; Ormsby, Christopher E.; Reyes-Terán, Gustavo

    2012-01-01

    Actinomyces and Mycobacterium avium-intracellulare are facultative intracellular organisms, members of the bacterial order actinomycetales. Although Actinomyces can behave as copathogen when anatomic barriers are compromised, its coinfection with Mycobacterium avium-intracellulare has not previously been reported. We present the first reported case of palatal actinomycosis co-infection with disseminated MAC, in an HIV-infected subject with Kaposi sarcoma and diabetes. We discuss the pathogenesis of the complex condition of this subject. PMID:22481952

  20. Resistance to Bacterial Pathogens in Plants

    E-print Network

    Innes, Roger

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

  1. INTRACELLULAR SURVIVAL OF STAPHYLOCOCCI

    PubMed Central

    Kapral, Frank A.; Shayegani, Mehdi Gh.

    1959-01-01

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

  2. Glutathione activates virulence gene expression of an intracellular pathogen

    PubMed Central

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

    2015-01-01

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

  3. Pyrimidine metabolism by intracellular Chlamydia psittaci.

    PubMed Central

    McClarty, G; Qin, B

    1993-01-01

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

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

    PubMed

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

    2009-12-01

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

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

    PubMed

    Lee, Stacey B

    2010-01-01

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

  6. Bacterial Vaginosis

    MedlinePLUS

    ... 563-586. Related Content STDs & Pregnancy Fact Sheet Pregnancy and HIV, Viral Hepatitis, and STD Prevention Pelvic Inflammatory Disease ( ... Page Bacterial Vaginosis (BV) Chlamydia Gonorrhea Genital Herpes HIV/AIDS & STDs Human Papillomavirus ... STDs See Also Pregnancy Reproductive ...

  7. 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...

  8. Symbiosis and Insect Diversification: an Ancient Symbiont of Sap-Feeding Insects from the Bacterial Phylum Bacteroidetes

    Microsoft Academic Search

    Nancy A. Moran; Phat Tran; Nicole M. Gerardo

    2005-01-01

    Several insect groups have obligate, vertically transmitted bacterial symbionts that provision hosts with nutrients that are limiting in the diet. Some of these bacteria have been shown to descend from ancient infections. Here we show that the large group of related insects including cicadas, leafhoppers, treehoppers, spittlebugs, and planthoppers host a distinct clade of bacterial symbionts. This newly described symbiont

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

    PubMed

    Johnson, David H

    2014-01-01

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

  10. Men as caregivers: reciprocal relationships or obligation?

    PubMed

    Neufeld, A; Harrison, M J

    1998-11-01

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

  11. Bacterial lipases

    Microsoft Academic Search

    Onno Misset; Margreet van Heuvel; Charles Colson; Bauke W. Dijkstra; Stéphane Ransac; Karl-Erich Jaeger

    1994-01-01

    Many different bacterial species produce lipases which hydrolyze esters of glycerol with preferably long-chain fatty acids. They act at the interface generated by a hydrophobic lipid substrate in a hydrophilic aqueous medium. A characteristic property of lipases is called interfacial activation, meaning a sharp increase in lipase activity observed when the substrate starts to form an emulsion, thereby presenting to

  12. [Bacterial Keratitis].

    PubMed

    Rachwalik, D; Pleyer, U

    2015-06-01

    Worldwide inflammatory corneal diseases are considered to be one of the leading causes of monocular blindness. Bacterial infectious are still predominant and are found in 80?% of patients with ulcerative keratitis. In recent years, both changes in risk conditions and changes in the bacterial spectrum can be observed. Contact lenses and refractive surgery are factors that have increased in importance according to some studies. Microorganisms especially Pseudomonas spp. and atypical mycobacteria are detectable in these patients. In contrast, the bacterial keratitis is observed less frequently after trauma. The broad, often unsighted use of highly effective antimicrobial agents, especially of fluoroquinolones is assumed to be a factor in the transformation of the microbial spectrum. Due to the frequent course of keratitis and a targeted, effective therapy to initiate a pathogen is desirable. The possibilities of diagnostics have been expanded in recent years by molecular biological techniques, but cannot replace established methods. The aim of this paper is to provide a positioning on current aspects of bacterial keratitis. PMID:26084962

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

    PubMed

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

    2015-08-01

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

  14. Dynamic Reorganization of Metabolic Enzymes into Intracellular Bodies

    PubMed Central

    O’Connell, Jeremy D.; Zhao, Alice; Ellington, Andrew D.; Marcotte, Edward M.

    2013-01-01

    Both focused and large-scale cell biological and biochemical studies have revealed that hundreds of metabolic enzymes across diverse organisms form large intracellular bodies. These proteinaceous bodies range in form from fibers and intracellular foci—such as those formed by enzymes of nitrogen and carbon utilization and of nucleotide biosynthesis—to high-density packings inside bacterial microcompartments and eukaryotic microbodies. Although many enzymes clearly form functional mega-assemblies, it is not yet clear for many recently discovered cases whether they represent functional entities, storage bodies, or aggregates. In this article, we survey intracellular protein bodies formed by metabolic enzymes, asking when and why such bodies form and what their formation implies for the functionality—and dysfunctionality—of the enzymes that comprise them. The panoply of intracellular protein bodies also raises interesting questions regarding their evolution and maintenance within cells. We speculate on models for how such structures form in the first place and why they may be inevitable. PMID:23057741

  15. Experimental selection of long-term intracellular mycobacteria

    PubMed Central

    Vázquez, Cristina L; Lerner, Thomas R; Kasmapour, Bahram; Pei, Gang; Gronow, Achim; Bianco, Maria V; Blanco, Federico C; Bleck, Christopher K E; Geffers, Robert; Bigi, Fabiana; Abraham, Wolf-Rainer; Gutierrez, Maximiliano G

    2014-01-01

    Some intracellular bacteria are known to cause long-term infections that last decades without compromising the viability of the host. Although of critical importance, the adaptations that intracellular bacteria undergo during this long process of residence in a host cell environment remain obscure. Here, we report a novel experimental approach to study the adaptations of mycobacteria imposed by a long-term intracellular lifestyle. Selected Mycobacterium bovis?BCG through continuous culture in macrophages underwent an adaptation process leading to impaired phenolic glycolipids (PGL) synthesis, improved usage of glucose as a carbon source and accumulation of neutral lipids. These changes correlated with increased survival of mycobacteria in macrophages and mice during re-infection and also with the specific expression of stress- and survival-related genes. Our findings identify bacterial traits implicated in the establishment of long-term cellular infections and represent a tool for understanding the physiological states and the environment that bacteria face living in fluctuating intracellular environments. PMID:24779357

  16. 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

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

    Microsoft Academic Search

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

    2009-01-01

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

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

    SciTech Connect

    Alexander, C.B.

    1997-02-01

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

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

    PubMed

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

    2004-08-26

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

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

    Microsoft Academic Search

    Jason D. Hans

    2008-01-01

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

  1. 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…

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

    E-print Network

    Paris-Sud XI, Université de

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

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2011-04-01

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

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

    PubMed Central

    Sloan, Daniel B.; Moran, Nancy A.

    2013-01-01

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

  6. 20 CFR 655.20 - Assurances and obligations of H-2B employers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  7. 20 CFR 655.20 - Assurances and obligations of H-2B employers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  8. 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....

  9. 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....

  10. 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....

  11. 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....

  12. 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....

  13. 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....

  14. 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....

  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 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....

  17. Exit strategies of intracellular pathogens

    Microsoft Academic Search

    Kevin Hybiske; Richard S. Stephens

    2008-01-01

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

  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 Accumulation of the Monomeric Precursors of Polyphosphates and Polyhydroxyalkanoates in Acinetobacter calcoaceticusand Escherichia coliCells

    Microsoft Academic Search

    A. I. Saralov; D. V. Mol'kov; O. M. Bannikova; A. P. Solomennyi; S. M. Chikin

    2001-01-01

    The formation of polyhydroxyalkanoates granules in anaerobically grown Escherichia coliM-17 cells was found to be preceded by the intracellular accumulation of carbonic acids (predominantly, acetic acid), amounting to 9% of the cytosol. The intracellular concentration of acidic metabolites increased after the lyophilization of the bacterial biomass and decreased after its long-term storage (3.5–13.5 years). The decrease in the concentration of

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

    E-print Network

    Lu, Chang

    A microfluidic device for physical trapping and electrical lysis of bacterial cells Ning Bao 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

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

    PubMed Central

    Kenyon, Laura J.; Sabree, Zakee L.

    2014-01-01

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

  2. Evolutionary replacement of obligate symbionts in an ancient and diverse insect lineage.

    PubMed

    Koga, Ryuichi; Bennett, Gordon M; Cryan, Jason R; Moran, Nancy A

    2013-07-01

    Many insect groups depend on ancient obligate symbioses with bacteria that undergo long-term genomic degradation due to inactivation and loss of ancestral genes. Sap-feeding insects in the hemipteran suborder Auchenorrhyncha show complex symbioses with at least two obligate bacterial symbionts, inhabiting specialized host cells (bacteriocytes). We explored the symbiotic relationships of the spittlebugs (Auchenorrhyncha: Cercopoidea) using phylogenetic and microscopy methods. Results show that most spittlebugs contain the symbionts Sulcia muelleri (Bacteroidetes) and Zinderia insecticola (Betaproteobacteria) with each restricted to its own bacteriocyte type. However, the ancestral Zinderia symbiont has been replaced with a novel symbiont closely related to Sodalis glossinidius (Enterobacteriaceae) in members of the ecologically successful spittlebug tribe Philaenini. At least one spittlebug species retains Sulcia and Zinderia, but also has acquired a Sodalis-like symbiont, possibly representing a transitional stage in the evolutionary succession of symbioses. Phylogenetic analyses including symbionts of other Auchenorrhyncha lineages suggest that Zinderia, like Sulcia, descends from an ancestral symbiont present in the common ancestor of Auchenorrhyncha. This betaproteobacterial symbiont has been repeatedly replaced by other symbionts, such as the Sodalis-like symbiont of spittlebugs. Symbiont replacement may offer a route for hosts to escape dependence on an ancient, degraded and potentially inefficient symbiont. PMID:23574391

  3. 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

  4. Isolation and Total Synthesis of Kirkamide, an Aminocyclitol from an Obligate Leaf Nodule Symbiont.

    PubMed

    Sieber, Simon; Carlier, Aurélien; Neuburger, Markus; Grabenweger, Giselher; Eberl, Leo; Gademann, Karl

    2015-06-26

    The new C7 N aminocyclitol kirkamide (1) was isolated from leaf nodules of the plant Psychotria kirkii by using a genome-driven (1) H?NMR-guided fractionation approach. The structure and absolute configuration were elucidated by HRMS, NMR, and single-crystal X-ray crystallography. An enantioselective total synthesis was developed, which delivered kirkamide (1) on a gram scale in 11?steps and features a Ferrier carbocyclization and a Pd-mediated hydroxymethylation. We propose that kirkamide is synthesized by Candidatus Burkholderia kirkii, the obligate leaf symbiont of Psychotria kirkii. Kirkamide (1) was shown to be toxic to aquatic arthropods and insects, thus suggesting that bacterial secondary metabolites play a protective role in the Psychotria/Burkholderia leaf nodule symbiosis. PMID:26033226

  5. 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...

  6. 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...

  7. 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...

  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. 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...

  10. 22 CFR 232.07 - Fiscal agent obligations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  11. 22 CFR 232.07 - Fiscal agent obligations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

  12. 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...

  13. 31 CFR 223.18 - Performance of agency obligations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  14. 47 CFR 64.3001 - Obligation to transmit 911 calls.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  15. 47 CFR 64.3001 - Obligation to transmit 911 calls.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  16. 47 CFR 64.3001 - Obligation to transmit 911 calls.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  17. 47 CFR 64.3001 - Obligation to transmit 911 calls.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  18. 47 CFR 64.3001 - Obligation to transmit 911 calls.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  19. 43 CFR 3162.2 - Drilling, producing, and drainage obligations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  20. 43 CFR 3162.2 - Drilling, producing, and drainage obligations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  1. 43 CFR 3162.2 - Drilling, producing, and drainage obligations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  2. 43 CFR 3162.2 - Drilling, producing, and drainage obligations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  3. 32 CFR 901.25 - Obligation of cadet appointment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  4. 18 CFR 346.3 - Asset retirement obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  5. 15 CFR 711.4 - Assistance in determining your obligations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  6. 29 CFR 1980.102 - Obligations and prohibited acts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  7. 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...

  8. 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...

  9. 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...

  10. Identification of a Novel Small Non-Coding RNA Modulating the Intracellular Survival of Brucella melitensis

    PubMed Central

    Wang, Yufei; Ke, Yuehua; Xu, Jie; Wang, Ligui; Wang, Tongkun; Liang, Hui; Zhang, Wei; Gong, Chunli; Yuan, Jiuyun; Zhuang, Yubin; An, Chang; Lei, Shuangshuang; Du, Xinying; Wang, Zhoujia; Li, Wenna; Yuan, Xitong; Huang, Liuyu; Yang, Xiaoli; Chen, Zeliang

    2015-01-01

    Bacterial small non-coding RNAs (sRNAs) are gene expression modulators respond to environmental changes, stressful conditions, and pathogenesis. In this study, by using a combined bioinformatic and experimental approach, eight novel sRNA genes were identified in intracellular pathogen Brucella melitensis. BSR0602, one sRNA that was highly induced in stationary phase, was further examined and found to modulate the intracellular survival of B. melitensis. BSR0602 was present at very high levels in vitro under stresses similar to those encountered during infection in host macrophages. Furthermore, BSR0602 was found to be highly expressed in the spleens of infected mice, suggesting its potential role in the control of pathogenesis. BSR0602 targets the mRNAs coding for gntR, a global transcriptional regulator, which is required for B. melitensis virulence. Overexpression of BSR0602 results in distinct reduction in the gntR mRNA level. B. melitensis with high level of BSR0602 is defective in bacteria intracellular survival in macrophages and defective in growth in the spleens of infected mice. Therefore, BSR0602 may directly inhibit the expression of gntR, which then impairs Brucellae intracellular survival and contributes to Brucella infection. Our findings suggest that BSR0602 is responsible for bacterial adaptation to stress conditions and thus modulate B. melitensis intracellular survival. PMID:25852653

  11. Identification of a Novel Small Non-Coding RNA Modulating the Intracellular Survival of Brucella melitensis.

    PubMed

    Wang, Yufei; Ke, Yuehua; Xu, Jie; Wang, Ligui; Wang, Tongkun; Liang, Hui; Zhang, Wei; Gong, Chunli; Yuan, Jiuyun; Zhuang, Yubin; An, Chang; Lei, Shuangshuang; Du, Xinying; Wang, Zhoujia; Li, Wenna; Yuan, Xitong; Huang, Liuyu; Yang, Xiaoli; Chen, Zeliang

    2015-01-01

    Bacterial small non-coding RNAs (sRNAs) are gene expression modulators respond to environmental changes, stressful conditions, and pathogenesis. In this study, by using a combined bioinformatic and experimental approach, eight novel sRNA genes were identified in intracellular pathogen Brucella melitensis. BSR0602, one sRNA that was highly induced in stationary phase, was further examined and found to modulate the intracellular survival of B. melitensis. BSR0602 was present at very high levels in vitro under stresses similar to those encountered during infection in host macrophages. Furthermore, BSR0602 was found to be highly expressed in the spleens of infected mice, suggesting its potential role in the control of pathogenesis. BSR0602 targets the mRNAs coding for gntR, a global transcriptional regulator, which is required for B. melitensis virulence. Overexpression of BSR0602 results in distinct reduction in the gntR mRNA level. B. melitensis with high level of BSR0602 is defective in bacteria intracellular survival in macrophages and defective in growth in the spleens of infected mice. Therefore, BSR0602 may directly inhibit the expression of gntR, which then impairs Brucellae intracellular survival and contributes to Brucella infection. Our findings suggest that BSR0602 is responsible for bacterial adaptation to stress conditions and thus modulate B. melitensis intracellular survival. PMID:25852653

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

    PubMed

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

    2015-03-01

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

  13. Differential requirement of P2X7 receptor and intracellular K+ for caspase-1 activation induced by intracellular and extracellular bacteria.

    PubMed

    Franchi, Luigi; Kanneganti, Thirumala-Devi; Dubyak, George R; Núñez, Gabriel

    2007-06-29

    Interleukin-1beta (IL-1beta) is a pro-inflammatory cytokine that plays an important role in host defense and inflammatory diseases. The maturation and secretion of IL-1beta are mediated by caspase-1, a protease that processes pro-IL-1beta into biologically active IL-1beta. The activity of caspase-1 is controlled by the inflammasome, a multiprotein complex formed by NLR proteins and the adaptor ASC, that induces the activation of caspase-1. The current model proposes that changes in the intracellular concentration of K(+) potentiate caspase-1 activation induced by the recognition of bacterial products. However, the roles of P2X7 receptor and intracellular K(+) in IL-1beta secretion induced by bacterial infection remain unknown. Here we show that, in response to Toll-like receptor agonists such as lipopolysaccharide or infection with extracellular bacteria Staphylococcus aureus and Escherichia coli, efficient caspase-1 activation is only triggered by addition of ATP, a signal that promotes caspase-1 activation through depletion of intracellular K(+) caused by stimulation of the purinergic P2X7 receptor. In contrast, activation of caspase-1 that relies on cytosolic sensing of flagellin or intracellular bacteria did not require ATP stimulation or depletion of cytoplasmic K(+). Consistently, caspase-1 activation induced by intracellular Salmonella or Listeria was unimpaired in macrophages deficient in P2X7 receptor. These results indicate that, unlike caspase-1 induced by Toll-like receptor agonists and ATP, activation of the inflammasome by intracellular bacteria and cytosolic flagellin proceeds normally in the absence of P2X7 receptor-mediated cytoplasmic K(+) perturbations. PMID:17491021

  14. Bacteriophage-aided intracellular killing of engulfed methicillin-resistant Staphylococcus aureus (MRSA) by murine macrophages.

    PubMed

    Kaur, Sandeep; Harjai, Kusum; Chhibber, Sanjay

    2014-05-01

    Phages are known to effectively kill extracellularly multiplying bacteria as they do not have the ability of intracellular penetration within the animal cells. However, the present manuscript focuses on studying the impact of surface-adsorbed phage particles on the killing of engulfed Staphylococcus aureus inside phagocytic cells. Mouse peritoneal macrophages were isolated and cultured, followed by evaluation of their ability of bacterial uptake and killing. The intracellular killing potential of macrophages in the presence of unadsorbed free phage as well as phage adsorbed onto S. aureus 43300 was studied. Phage added alone to macrophage preparation did not influence intracellular killing of engulfed S. aureus by macrophages. However, phage adsorbed onto host bacterial cells (utilizing host bacteria as a vehicle to carry the lytic phage into the phagocytic compartment) brought about time-dependent and titre-dependent significant reduction in the number of viable intracellular cocci. Phage particles that shuttled inside the macrophage along with bacteria also significantly reduced cytotoxic damage caused by methicillin-resistant S. aureus (MRSA). This in turn enhanced the bactericidal killing potential of phagocytic cells. In earlier studies the inability of phages to kill intracellular bacteria has been thought to be a major drawback of phage therapy. For the first time results of this study confirm the killing ability of the broad host range lytic phage MR-5 of both extracellular as well as intracellular engulfed S. aureus inside macrophages. This approach shall not only restrict intracellular proliferation of staphylococci within the myeloid cells but also protect the host from further relapse of infection and treatment failures. PMID:24633444

  15. Bacterial vaginosis.

    PubMed Central

    Spiegel, C A

    1991-01-01

    Bacterial vaginosis (BV) is the most common of the vaginitides affecting women of reproductive age. It appears to be due to an alteration in the vaginal ecology by which Lactobacillus spp., the predominant organisms in the healthy vagina, are replaced by a mixed flora including Prevotella bivia, Prevotella disiens, Porphyromonas spp., Mobiluncus spp., and Peptostreptococcus spp. All of these organisms except Mobiluncus spp. are also members of the endogenous vaginal flora. While evidence from treatment trials does not support the notion that BV is sexually transmitted, recent studies have shown an increased risk associated with multiple sexual partners. It has also been suggested that the pathogenesis of BV may be similar to that of urinary tract infections, with the rectum serving as a reservoir for some BV-associated flora. The organisms associated with BV have also been recognized as agents of female upper genital tract infection, including pelvic inflammatory disease, and the syndrome BV has been associated with adverse outcome of pregnancy, including premature rupture of membranes, chorioamnionitis, and fetal loss; postpartum endometritis; cuff cellulitis; and urinary tract infections. The mechanisms by which the BV-associated flora causes the signs of BV are not well understood, but a role for H2O2-producing Lactobacillus spp. in protecting against colonization by catalase-negative anaerobic bacteria has been recognized. These and other aspects of BV are reviewed. PMID:1747864

  16. Bacterial communities of two parthenogenetic aphid species cocolonizing two host plants across the Hawaiian Islands.

    PubMed

    Jones, Ryan T; Bressan, Alberto; Greenwell, April M; Fierer, Noah

    2011-12-01

    Aphids (Hemiptera: Aphididae) have been the focus of several studies with respect to their interactions with inherited symbionts, but bacterial communities of most aphid species are still poorly characterized. In this research, we used bar-coded pyrosequencing to characterize bacterial communities in aphids. Specifically, we examined the diversity of bacteria in two obligately parthenogenetic aphid species (the melon aphid, Aphis gossypii, and the cardamom aphid, Pentalonia caladii) cocolonizing two plant species (taro, Colocasia esculenta, and ginger, Alpinia purpurata) across four Hawaiian Islands (Hawaii, Kauai, Maui, and Oahu). Results from this study revealed that heritable symbionts dominated the bacterial communities for both aphid species. The bacterial communities differed significantly between the two species, and A. gossypii harbored a more diverse bacterial community than P. caladii. The bacterial communities also differed across aphid populations sampled from the different islands; however, communities did not differ between aphids collected from the two host plants. PMID:21965398

  17. [Intracellular calcium: physiology and physiopathology].

    PubMed

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

    2000-01-01

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

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

    PubMed

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

    2011-11-01

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

  19. 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.

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

    PubMed

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

    2008-09-01

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

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

    PubMed Central

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

    2012-01-01

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

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

    PubMed Central

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

    2013-01-01

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

  3. Intracellular Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in Buccal Epithelial Cells Collected from Human Subjects

    PubMed Central

    Rudney, Joel D.; Chen, Ruoqiong; Sedgewick, Gerald J.

    2001-01-01

    The mouth may provide an accessible model for studying bacterial interactions with human cells in vivo. Using fluorescent in situ hybridization and laser scanning confocal microscopy, we found that human buccal epithelial cells from 23 of 24 subjects were infected with intracellular bacteria, including the periodontal pathogens Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis, as well as other species which have yet to be identified. Buccal cell invasion may allow fastidious anaerobes to establish themselves in aerobic sites that otherwise present an unfavorable environment. Exfoliated buccal epithelial cells might provide a protected route for bacterial transmission between different oral sites within and between hosts. PMID:11254637

  4. Changes in cytosolic ATP levels and intracellular morphology during bacteria-induced hypersensitive cell death as revealed by real-time fluorescence microscopy imaging.

    PubMed

    Hatsugai, Noriyuki; Perez Koldenkova, Vadim; Imamura, Hiromi; Noji, Hiroyuki; Nagai, Takeharu

    2012-10-01

    Hypersensitive cell death is known to involve dynamic remodeling of intracellular structures that uses energy released during ATP hydrolysis. However, the relationship between intracellular structural changes and ATP levels during hypersensitive cell death remains unclear. Here, to visualize ATP dynamics directly in real time in individual living plant cells, we applied a genetically encoded Förster resonance energy transfer (FRET)-based fluorescent ATP indicator, ATeam1.03-nD/nA, for plant cells. Intracellular ATP levels increased approximately 3 h after inoculation with the avirulent strain DC3000/avrRpm1 of Pseudomonas syringae pv. tomato (Pst), which was accompanied by the simultaneous disappearance of transvacuolar strands and appearance of bulb-like structures within the vacuolar lumen. Approximately 5 h after bacterial inoculation, the bulb-like structures disappeared and ATP levels drastically decreased. After another 2 h, the large central vacuole was disrupted. In contrast, no apparent changes in intracellular ATP levels were observed in the leaves inoculated with the virulent strain Pst DC3000. The Pst DC3000/avrRpm1-induced hypersensitive cell death was strongly suppressed by inhibiting ATP synthesis after oligomycin A application within 4 h after bacterial inoculation. When the inhibitor was applied 7 h after bacterial inoculation, cell death was unaffected. These observations show that changes in intracellular ATP levels correlate with intracellular morphological changes during hypersensitive cell death, and that ATP is required just before vacuolar rupture in response to bacterial infection. PMID:22942251

  5. Intracellular ?-Amylase of Streptococcus mutans

    PubMed Central

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

    1998-01-01

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

  6. 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

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

    Microsoft Academic Search

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

    2011-01-01

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

  8. Circulating dendritic cell number and intracellular TNF-? production in women with type 2 diabetes

    Microsoft Academic Search

    Sally E. BlankEmily; Emily Carolyn Johnson; Carol H. Wysham

    Human dendritic cell (DC) subsets perform specialized functions for surveillance against bacterial and viral infections essential\\u000a for the management of type 2 diabetes (T2D). Production of tumor necrosis factor-alpha (TNF-?) by DCs acts in autocrine fashion\\u000a to regulate DC maturation and promotes the inflammatory response. This study was designed to compare circulating DC number\\u000a and intracellular TNF-? production between post-menopausal

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

    PubMed Central

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

    1998-01-01

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

  10. 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

  11. 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

  12. Intracellular Signaling by the Unfolded Protein

    E-print Network

    Mullins, Dyche

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

  13. Buckling and force propagation along intracellular microtubules

    E-print Network

    MacKintosh, F.C.

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

  14. Spatiological processes in intracellular signalling Michael Fisher

    E-print Network

    Malcolm, Grant

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

  15. 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

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

    PubMed

    Stuifbergen, Maria C; Van Delden, Johannes J M

    2011-02-01

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

  17. 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

  18. 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

  19. 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.

  20. 24 CFR 891.755 - Obligations of the family.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

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

    ERIC Educational Resources Information Center

    Hartmeister, Fred

    1990-01-01

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

  2. 7 CFR 930.163 - Deferment of restricted obligation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

  3. 7 CFR 930.163 - Deferment of restricted obligation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  4. 7 CFR 930.163 - Deferment of restricted obligation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  5. 7 CFR 930.163 - Deferment of restricted obligation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  6. 7 CFR 930.163 - Deferment of restricted obligation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  7. 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)

  8. Tracking Trends In Provider Reimbursements And Patient Obligations.

    PubMed

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

    2015-07-01

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

  9. Intracellular Demography and the Dynamics of Salmonella enterica Infections

    PubMed Central

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

    2006-01-01

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

  10. Calcium efflux is essential for bacterial survival in the eukaryotic host

    PubMed Central

    Rosch, Jason W.; Sublett, Jack; Gao, Geli; Wang, Yong-Dong; Tuomanen, Elaine I.

    2008-01-01

    Summary In dynamic environments, intracellular homeostasis is maintained by transport systems found in all cells. While bacterial influx systems for essential trace cations are known to contribute to pathogenesis, efflux systems have been characterized mainly in contaminated environmental sites. We describe that the high calcium concentrations in the normal human host were toxic to pneumococci and that bacterial survival in vivo depended on CaxP, the first Ca2+ exporter reported in bacteria. CaxP homologs were found in the eukaryotic sacroplasmic reticulum and in many bacterial genomes. A caxP- mutant accumulated intracellular calcium, a state that was used to reveal signaling networks responsive to changes in intracellular calcium concentration. Chemical inhibition of CaxP was bacteriostatic in physiological calcium concentrations, suggesting a new antibiotic target uncovered under conditions in the eukaryotic host. PMID:18761687

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

    PubMed Central

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

    2008-01-01

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

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

    PubMed

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

    2008-10-01

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

  13. Bacterial recognition pathways that lead to inflammasome activation

    PubMed Central

    Storek, Kelly M; Monack, Denise M

    2015-01-01

    Inflammasomes are multi-protein signaling platforms that upon activation trigger the maturation of the pro-inflammatory cytokines, interleukin-1? (IL-1?) and IL-18, and cell death. Inflammasome sensors detect microbial and host-derived molecules. Here, we review the mechanisms of inflammasome activation triggered by bacterial infection, primarily focusing on two model intracellular bacterial pathogens, Francisella novicida and Salmonella typhimurium. We discuss the complex relationship between bacterial recognition through direct and indirect detection by inflammasome sensors. We highlight regulation mechanisms that potentiate or limit inflammasome activation. We discuss the importance of caspase-1 and caspase-11 in host defense, and we examine the downstream consequences of inflammasome activation within the context of bacterial infections. PMID:25879288

  14. Bacterial recognition pathways that lead to inflammasome activation.

    PubMed

    Storek, Kelly M; Monack, Denise M

    2015-05-01

    Inflammasomes are multi-protein signaling platforms that upon activation trigger the maturation of the pro-inflammatory cytokines, interleukin-1? (IL-1?) and IL-18, and cell death. Inflammasome sensors detect microbial and host-derived molecules. Here, we review the mechanisms of inflammasome activation triggered by bacterial infection, primarily focusing on two model intracellular bacterial pathogens, Francisella novicida and Salmonella typhimurium. We discuss the complex relationship between bacterial recognition through direct and indirect detection by inflammasome sensors. We highlight regulation mechanisms that potentiate or limit inflammasome activation. We discuss the importance of caspase-1 and caspase-11 in host defense, and we examine the downstream consequences of inflammasome activation within the context of bacterial infections. PMID:25879288

  15. 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...

  16. 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...

  17. 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...

  18. 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...

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

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  1. 31 CFR 1010.311 - Filing obligations for reports of transactions in currency.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  2. 31 CFR 1010.311 - Filing obligations for reports of transactions in currency.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  3. 31 CFR 1010.311 - Filing obligations for reports of transactions in currency.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  4. 31 CFR 1010.311 - Filing obligations for reports of transactions in currency.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  5. Hill-Burton Facilities Obligated to Provide Free or Reduced-Cost Health Care

    MedlinePLUS

    ... Facilities Obligated to Provide Free or Reduced-Cost Health Care Total Obligated Facilities: 152 (03/31/2015) No ... 463-7313 Outpatient Facility 120270 PFCA FL RURAL HEALTH CARE, INC 1213 STATE ROAD 20 INTERLACHEN 32148 386- ...

  6. 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....

  7. 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....

  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, 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...

  10. 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...

  11. 24 CFR 811.110 - Refunding of obligations issued to finance Section 8 projects.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...false Refunding of obligations issued to finance Section 8 projects. 811.110 Section...110 Refunding of obligations issued to finance Section 8 projects. (a) This...savings and, if necessary, HUD will finance in refunding bond debt service...

  12. 24 CFR 811.110 - Refunding of obligations issued to finance Section 8 projects.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...false Refunding of obligations issued to finance Section 8 projects. 811.110 Section...110 Refunding of obligations issued to finance Section 8 projects. (a) This...savings and, if necessary, HUD will finance in refunding bond debt service...

  13. 24 CFR 811.110 - Refunding of obligations issued to finance Section 8 projects.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...false Refunding of obligations issued to finance Section 8 projects. 811.110 Section...110 Refunding of obligations issued to finance Section 8 projects. (a) This...savings and, if necessary, HUD will finance in refunding bond debt service...

  14. 24 CFR 811.110 - Refunding of obligations issued to finance Section 8 projects.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...false Refunding of obligations issued to finance Section 8 projects. 811.110 Section...110 Refunding of obligations issued to finance Section 8 projects. (a) This...savings and, if necessary, HUD will finance in refunding bond debt service...

  15. 12 CFR 617.7400 - What protections exist for borrowers who meet all loan obligations?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...What protections exist for borrowers who meet all loan obligations? 617.7400 Section...protections exist for borrowers who meet all loan obligations? (a) A qualified...additional collateral when the borrower has made all accrued payments of principal,...

  16. 20 CFR 655.1305 - Assurances and obligations of H-2A employers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Assurances and obligations of H-2A employers. 655.1305 Section 655.1305 Employees' Benefits EMPLOYMENT AND TRAINING...Employment in the United States (H-2A Workers) § 655.1305 Assurances and obligations of H-2A...

  17. 20 CFR 655.1305 - Assurances and obligations of H-2A employers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Assurances and obligations of H-2A employers. 655.1305 Section 655.1305 Employees' Benefits EMPLOYMENT AND TRAINING...Employment in the United States (H-2A Workers) § 655.1305 Assurances and obligations of H-2A...

  18. 20 CFR 655.1305 - Assurances and obligations of H-2A employers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Assurances and obligations of H-2A employers. 655.1305 Section 655.1305 Employees' Benefits EMPLOYMENT AND TRAINING...Employment in the United States (H-2A Workers) § 655.1305 Assurances and obligations of H-2A...

  19. 20 CFR 655.1305 - Assurances and obligations of H-2A employers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Assurances and obligations of H-2A employers. 655.1305 Section 655.1305 Employees' Benefits EMPLOYMENT AND TRAINING...Employment in the United States (H-2A Workers) § 655.1305 Assurances and obligations of H-2A...

  20. 20 CFR 655.1305 - Assurances and obligations of H-2A employers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Assurances and obligations of H-2A employers. 655.1305 Section 655.1305 Employees' Benefits EMPLOYMENT AND TRAINING...Employment in the United States (H-2A Workers) § 655.1305 Assurances and obligations of H-2A...

  1. 20 CFR 655.135 - Assurances and obligations of H-2A employers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Assurances and obligations of H-2A employers. 655.135 Section 655.135 Employees' Benefits EMPLOYMENT AND TRAINING...Temporary Employment Certification Filing Procedures § 655.135 Assurances and obligations of H-2A...

  2. 43 CFR 9.11 - What are the Secretary's obligations in interstate situations?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Secretary's obligations in interstate situations? 9.11 Section 9.11 Public Lands: Interior Office of the Secretary...DEPARTMENT OF THE INTERIOR PROGRAMS AND ACTIVITIES § 9.11 What are the Secretary's obligations in...

  3. 43 CFR 9.11 - What are the Secretary's obligations in interstate situations?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Secretary's obligations in interstate situations? 9.11 Section 9.11 Public Lands: Interior Office of the Secretary...DEPARTMENT OF THE INTERIOR PROGRAMS AND ACTIVITIES § 9.11 What are the Secretary's obligations in...

  4. 43 CFR 9.11 - What are the Secretary's obligations in interstate situations?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Secretary's obligations in interstate situations? 9.11 Section 9.11 Public Lands: Interior Office of the Secretary...DEPARTMENT OF THE INTERIOR PROGRAMS AND ACTIVITIES § 9.11 What are the Secretary's obligations in...

  5. 43 CFR 9.11 - What are the Secretary's obligations in interstate situations?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Secretary's obligations in interstate situations? 9.11 Section 9.11 Public Lands: Interior Office of the Secretary...DEPARTMENT OF THE INTERIOR PROGRAMS AND ACTIVITIES § 9.11 What are the Secretary's obligations in...

  6. 43 CFR 9.11 - What are the Secretary's obligations in interstate situations?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Secretary's obligations in interstate situations? 9.11 Section 9.11 Public Lands: Interior Office of the Secretary...DEPARTMENT OF THE INTERIOR PROGRAMS AND ACTIVITIES § 9.11 What are the Secretary's obligations in...

  7. 26 CFR 1.662(a)-4 - Amounts used in discharge of a legal obligation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Amounts used in discharge of a legal obligation. 1...662(a)-4 Amounts used in discharge of a legal obligation. Any...instrument, is used in full or partial discharge or satisfaction of a...

  8. 26 CFR 1.662(a)-4 - Amounts used in discharge of a legal obligation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false Amounts used in discharge of a legal obligation. 1...662(a)-4 Amounts used in discharge of a legal obligation. Any...instrument, is used in full or partial discharge or satisfaction of a...

  9. 26 CFR 1.662(a)-4 - Amounts used in discharge of a legal obligation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Amounts used in discharge of a legal obligation. 1...662(a)-4 Amounts used in discharge of a legal obligation. Any...instrument, is used in full or partial discharge or satisfaction of a...

  10. 26 CFR 1.662(a)-4 - Amounts used in discharge of a legal obligation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Amounts used in discharge of a legal obligation. 1...662(a)-4 Amounts used in discharge of a legal obligation. Any...instrument, is used in full or partial discharge or satisfaction of a...

  11. 18 CFR 367.2430 - Account 243, Obligations under capital leases-Current.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...243, Obligations under capital leases-Current. 367.2430 Section 367.2430 ...ACT Balance Sheet Chart of Accounts Current and Accrued Liabilities § 367.2430...Obligations under capital leases—Current. This account must include the...

  12. 18 CFR 367.2430 - Account 243, Obligations under capital leases-Current.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...243, Obligations under capital leases-Current. 367.2430 Section 367.2430 ...ACT Balance Sheet Chart of Accounts Current and Accrued Liabilities § 367.2430...Obligations under capital leases—Current. This account must include the...

  13. 29 CFR 37.29 - What are a recipient's obligations to disseminate its equal opportunity policy?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...obligations to disseminate its equal opportunity policy? 37.29 Section...OF THE NONDISCRIMINATION AND EQUAL OPPORTUNITY PROVISIONS OF THE WORKFORCE...obligations to disseminate its equal opportunity policy? (a) A...

  14. 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...

  15. 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...

  16. 21 CFR 312.52 - Transfer of obligations to a contract research organization.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Transfer of obligations to a contract research organization. 312.52 Section...Transfer of obligations to a contract research organization. (a) A sponsor...forth in this part to a contract research organization. Any such...

  17. 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...

  18. 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...

  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. Manganese (Mn) Oxidation Increases Intracellular Mn in Pseudomonas putida GB-1

    PubMed Central

    Banh, Andy; Chavez, Valarie; Doi, Julia; Nguyen, Allison; Hernandez, Sophia; Ha, Vu; Jimenez, Peter; Espinoza, Fernanda; Johnson, Hope A.

    2013-01-01

    Bacterial manganese (Mn) oxidation plays an important role in the global biogeochemical cycling of Mn and other compounds, and the diversity and prevalence of Mn oxidizers have been well established. Despite many hypotheses of why these bacteria may oxidize Mn, the physiological reasons remain elusive. Intracellular Mn levels were determined for Pseudomonas putida GB-1 grown in the presence or absence of Mn by inductively coupled plasma mass spectrometry (ICP-MS). Mn oxidizing wild type P. putida GB-1 had higher intracellular Mn than non Mn oxidizing mutants grown under the same conditions. P. putida GB-1 had a 5 fold increase in intracellular Mn compared to the non Mn oxidizing mutant P. putida GB-1-007 and a 59 fold increase in intracellular Mn compared to P. putida GB-1 ?2665 ?2447. The intracellular Mn is primarily associated with the less than 3 kDa fraction, suggesting it is not bound to protein. Protein oxidation levels in Mn oxidizing and non oxidizing cultures were relatively similar, yet Mn oxidation did increase survival of P. putida GB-1 when oxidatively stressed. This study is the first to link Mn oxidation to Mn homeostasis and oxidative stress protection. PMID:24147089

  1. The role of TREM-2 in internalization and intracellular survival of Brucella abortus in murine macrophages.

    PubMed

    Wei, Pan; Lu, Qiang; Cui, Guimei; Guan, Zhenhong; Yang, Li; Sun, Changjiang; Sun, Wanchun; Peng, Qisheng

    2015-02-15

    Triggering receptor expressed on myeloid cells-2 (TREM-2) is a cell surface receptor primarily expressed on macrophages and dendritic cells. TREM-2 functions as a phagocytic receptor for bacteria as well as an inhibitor of Toll like receptors (TLR) induced inflammatory cytokines. However, the role of TREM-2 in Brucella intracellular growth remains unknown. To investigate whether TREM-2 is involved in Brucella intracellular survival, we chose bone marrow derived macrophages (BMDMs), in which TREM-2 is stably expressed, as cell model. Colony formation Units (CFUs) assay suggests that TREM-2 is involved in the internalization of Brucella abortus (B. abortus) by macrophages, while silencing of TREM-2 decreases intracellular survival of B. abortus. To further study the underlying mechanisms of TREM-2-mediated bacterial intracellular survival, we examined the activation of B. abortus-infected macrophages through determining the kinetics of activation of the three MAPKs, including ERK, JNK and p38, and measuring TNF? production in response to lipopolysaccharide (LPS) of Brucella (BrLPS) or B. abortus stimulation. Our data show that TREM-2 deficiency promotes activation of Brucella-infected macrophages. Moreover, our data also demonstrate that macrophage activation promotes killing of Brucella by enhancing nitric oxygen (NO), but not reactive oxygen species (ROS) production, macrophage apoptosis or cellular death. Taken together, these findings provide a novel interpretation of Brucella intracellular growth through inhibition of NO production produced by TREM-2-mediated activated macrophages. PMID:25563793

  2. Intracellular signalling during neutrophil recruitment

    PubMed Central

    Mócsai, Attila; Walzog, Barbara; Lowell, Clifford A.

    2015-01-01

    Recruitment of leucocytes such as neutrophils to the extravascular space is a critical step of the inflammation process and plays a major role in the development of various diseases including several cardiovascular diseases. Neutrophils themselves play a very active role in that process by sensing their environment and responding to the extracellular cues by adhesion and de-adhesion, cellular shape changes, chemotactic migration, and other effector functions of cell activation. Those responses are co-ordinated by a number of cell surface receptors and their complex intracellular signal transduction pathways. Here, we review neutrophil signal transduction processes critical for recruitment to the site of inflammation. The two key requirements for neutrophil recruitment are the establishment of appropriate chemoattractant gradients and the intrinsic ability of the cells to migrate along those gradients. We will first discuss signalling steps required for sensing extracellular chemoattractants such as chemokines and lipid mediators and the processes (e.g. PI3-kinase pathways) leading to the translation of extracellular chemoattractant gradients to polarized cellular responses. We will then discuss signal transduction by leucocyte adhesion receptors (e.g. tyrosine kinase pathways) which are critical for adhesion to, and migration through the vessel wall. Finally, additional neutrophil signalling pathways with an indirect effect on the neutrophil recruitment process, e.g. through modulation of the inflammatory environment, will be discussed. Mechanistic understanding of these pathways provide better understanding of the inflammation process and may point to novel therapeutic strategies for controlling excessive inflammation during infection or tissue damage. PMID:25998986

  3. Intracellular signaling of cardiac fibroblasts.

    PubMed

    Roche, Patricia L; Filomeno, Krista L; Bagchi, Rushita A; Czubryt, Michael P

    2015-03-01

    Long regarded as a mere accessory cell for the cardiomyocyte, the cardiac fibroblast is now recognized as a critical determinant of cardiac function in health and disease. A recent renaissance in fibroblast-centered research has fostered a better understanding than ever before of the biology of fibroblasts and their contractile counterparts, myofibroblasts. While advanced methodological approaches, including transgenics, lineage fate mapping, and improved cell marker identification have helped to facilitate this new work, the primary driver is arguably the contribution of myofibroblasts to cardiac pathophysiology including fibrosis and arrhythmogenesis. Fibrosis is a natural sequel to numerous common cardiac pathologies including myocardial infarction and hypertension, and typically exacerbates cardiovascular disease and progression to heart failure, yet no therapies currently exist to specifically target fibrosis. The regulatory processes and intracellular signaling pathways governing fibroblast and myofibroblast behavior thus represent important points of inquiry for the development of antifibrotic treatments. While steady progress is being made in uncovering the signaling pathways specific for cardiac fibroblast function (including proliferation, phenotype conversion, and matrix synthesis), much of what is currently known of fibroblast signaling mechanisms is derived from noncardiac fibroblast populations. Given the heterogeneity of fibroblasts across tissues, this dearth of information further underscores the need for progress in cardiac fibroblast biological research. © 2015 American Physiological Society. Compr Physiol 5: 721-760, 2015. PMID:25880511

  4. Genome reduction in prokaryotic obligatory intracellular parasites of humans: a comparative analysis.

    PubMed

    Sakharkar, Kishore R; Dhar, Pawan Kumar; Chow, Vincent T K

    2004-11-01

    Obligatory intracellular parasites have undergone significant genome reduction by gene loss over time in the context of their obligate associations with the host. The flux, streamlining and elimination of genes in these genomes constitute a selective and ongoing process. Comparative analyses of five completely sequenced obligatory intracellular parasite genomes reveal that these genomes display marked similarities in patterns of protein length and frequency distribution, with substantial sharing of a 'backbone genome'. From category distribution based on the database of cluster of orthologous groups of proteins (COG), it is clear that habitat is a major factor contributing to genome reduction. It is also observed that, in all five obligatory intracellular parasites, the reduction in number of genes/proteins is greater for proteins with lengths of 200-600 amino acids. These comparative analyses highlight that gene loss is function-dependent, but is independent of protein length. These comparisons enhance our knowledge of the forces that drive the extreme specialization of the bacteria and their association with the host. PMID:15545414

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

    Microsoft Academic Search

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

    2010-01-01

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

  6. 30 CFR 243.8 - When will MMS suspend my obligation to comply with an order?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false When will MMS suspend my obligation to comply with an...General Provisions § 243.8 When will MMS suspend my obligation to comply with an...require payment of a specified amount, MMS will suspend your obligation to comply...

  7. 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)...

  8. 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)...

  9. 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)...

  10. 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)...

  11. 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)...

  12. Spatial aspects of intracellular information processing.

    PubMed

    Kinkhabwala, Ali; Bastiaens, Philippe I H

    2010-02-01

    The computational properties of intracellular biochemical networks, for which the cell is assumed to be a 'well-mixed' reactor, have already been widely characterized. What has so far not received systematic treatment is the important role of space in many intracellular computations. Spatial network computations can be divided into two broad categories: those required for essential spatial processes (e.g. polarization, chemotaxis, division, and development) and those for which space is simply used as an extra dimension to expand the computational power of the network. Several pertinent recent examples of each category are discussed that illustrate the often conceptually subtle role of space in the processing of intracellular information. PMID:20096560

  13. 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

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

    PubMed Central

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

    2015-01-01

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

  15. 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.

  16. US arms control obligations under the Non-Proliferation Treaty

    SciTech Connect

    Not Available

    1986-06-27

    Article VI of the 1968 Non-Proliferation Treaty (NPT) obligates the nuclear weapon states parties to the Treaty ''to pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race, ... to nuclear disarmament, and on a treaty on general and complete disarmament under strict and effective international control.'' The preamble to the NPT recalls the 1963 Limited Test Ban Treaty ''determination ... to achieve the discontinuance of ... explosions.'' These provisions are interpreted by a majority of the non-nuclear weapon states parties to the Treaty as an obligation of the nuclear weapon states parties to the Treaty to pursue a comprehensive test ban (CTB). However, a review of the history of the NPT negotiations and US ratification proceedings makes clear that the NPT imposes no legal obligation on the US to pursue a CTB. The US did not make a one-to-one correspondence between Article VI and any specific arms control measure; to the contrary, the US argued successfully that such a connection (to any specific measure) would be pernicious to the attempt to achieve agreement on the NPT. This interpretation, which was sustained through the negotiations and the ratification proceedings, still reflects the limits of the legal obligations the US has accepted. But, in the absence of progress on other arms control measures, which would relieve the pressure for a CTB, the majority interpretation creates political difficulties for the US and could threaten the NPT regime in the future. These problems highlight the need for the US to better defend its compliance with Article VI and to develop a long-term strategy that will permit necessary testing while assuring the survival of the NPT regime in effective form.

  17. Association between competition and obligate mutualism in a chemostat.

    PubMed

    El Hajji, Miled; Harmand, Jérôme; Chaker, Hédia; Lobry, Claude

    2009-11-01

    In this paper, we consider a simple chemostat model involving two obligate mutualistic species feeding on a limiting substrate. Systems of differential equations are proposed as models of this association. A detailed qualitative analysis is carried out. We show the existence of a domain of coexistence, which is a set of initial conditions in which both species survive. We demonstrate, under certain supplementary assumptions, the uniqueness of the stable equilibrium point which corresponds to the coexistence of the two species. PMID:22880965

  18. Price Regulation and Public Service Obligations under International Arbitrage

    Microsoft Academic Search

    Giorgio Matteucci; Pierfrancesco Reverberi

    2005-01-01

    National regulation generates price differentials between countries stimulating arbitrage by international distributors. Harmed manufacturers counteract using vertical price-squeeze or non-price discrimination. We show that: (i) either under regulatory commitment or discretion, there are non-linear relationships between technology\\/market conditions and the first-mover’s pricing strategy; (ii) public service obligations on distributors allow regulators to manipulate parallel exports so as to improve national

  19. 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

  20. Intracellular biopotentials during static extracellular stimulation.

    PubMed

    Klee, M

    1973-08-01

    Two properties of the intracellular potentials and electric fields resulting from static extracellular stimulation are obtained for arbitrarily shaped cells. First, the values of intracellular potential are shown to be bounded by the maximum and minimum values of extracellular potential on the surface of the cell. Second, the volume average of the magnitude of intracellular electric field is shown to have an upper bound given by the ratio of the magnitude of the largest extracellular potential difference on the surface of the cell to a generalized length constant lambda = [sigma(intra)V(cell)/(sigma(memb)A(cell))](1/2), where V(cell) and A(cell) are the volume and surface area of the cell, sigma(intra) is the intracellular conductivity (reciprocal ohms per centimeter), and sigma(memb) is the membrane conductivity (reciprocal ohms per square centimeter). The use of the upper bound on the volume average of the magnitude of intracellular electric field as an estimate for intracellular isopotentiality is discussed and the use of the generalized length constant for electrically describing arbitrary cells is illustrated for cylindrical- and spheroidal-shaped cells. PMID:4726882

  1. Desulfurispira natronophila gen. nov. sp. nov.: an obligately anaerobic dissimilatory sulfur-reducing bacterium from soda lakes

    PubMed Central

    Muyzer, G.

    2010-01-01

    Anaerobic enrichment cultures with elemental sulfur as electron acceptor and either acetate or propionate as electron donor and carbon source at pH 10 and moderate salinity inoculated with sediments from soda lakes in Kulunda Steppe (Altai, Russia) resulted in the isolation of two novel members of the bacterial phylum Chrysiogenetes. The isolates, AHT11 and AHT19, represent the first specialized obligate anaerobic dissimilatory sulfur respirers from soda lakes. They use either elemental sulfur/polysulfide or arsenate as electron acceptor and a few simple organic compounds as electron donor and carbon source. Elemental sulfur is reduced to sulfide through intermediate polysulfide, while arsenate is reduced to arsenite. The bacteria belong to the obligate haloalkaliphiles, with a pH growth optimum from 10 to 10.2 and a salt range from 0.2 to 3.0 M Na+ (optimum 0.4–0.6 M). According to the phylogenetic analysis, the two strains were close to each other, but distinct from the nearest relative, the haloalkaliphilic sulfur-reducing bacterium Desulfurispirillum alkaliphilum, which was isolated from a bioreactor. On the basis of distinct phenotype and phylogeny, the soda lake isolates are proposed as a new genus and species, Desulfurispira natronophila (type strain AHT11T = DSM22071T = UNIQEM U758T). Electronic supplementary material The online version of this article (doi:10.1007/s00792-010-0314-7) contains supplementary material, which is available to authorized users. PMID:20407798

  2. Glutathione deficiency in type 2 diabetes impairs cytokine responses and control of intracellular bacteria.

    PubMed

    Tan, Kai Soo; Lee, Kok Onn; Low, Kee Chung; Gamage, Akshamal Mihiranga; Liu, Yichun; Tan, Gek-Yen Gladys; Koh, Hui Qi Vanessa; Alonso, Sylvie; Gan, Yunn-Hwen

    2012-06-01

    Individuals with type 2 diabetes are at increased risk of acquiring melioidosis, a disease caused by Burkholderia pseudomallei infection. Although up to half of melioidosis patients have underlying diabetes, the mechanisms involved in this increased susceptibility are unknown. We found that B. pseudomallei-infected PBMCs from diabetic patients were impaired in IL-12p70 production, which resulted in decreased IFN-? induction and poor bacterial killing. The defect was specific to the IL-12-IFN-? axis. Defective IL-12 production was also observed during Mycobacterium tuberculosis infection, in which diabetes is likewise known to be a strong risk factor. In contrast, IL-12 production in diabetic cells was not affected upon Salmonella enterica infection or in response to TLR2, -3, -4, and -5 ligands. Poor IL-12 production correlated with a deficiency in intracellular reduced glutathione (GSH) concentrations in diabetic patients. Addition of GSH or N-acetylcysteine to PBMCs selectively restored IL-12 and IFN-? production and improved bacterial killing. Furthermore, the depletion of GSH in mice led to increased susceptibility to melioidosis, reduced production of IL-12p70, and poorer disease outcome. Our data thus establish a link between GSH deficiency in diabetes and increased susceptibility to melioidosis that may open up new therapeutic avenues to protect diabetic patients against some intracellular bacterial pathogens. PMID:22546856

  3. 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

  4. Intracellular Vesicles as Reproduction Elements in Cell Wall-Deficient L-Form Bacteria

    PubMed Central

    Briers, Yves; Staubli, Titu; Schmid, Markus C.; Wagner, Michael; Schuppler, Markus; Loessner, Martin J.

    2012-01-01

    Cell wall-deficient bacteria, or L-forms, represent an extreme example of bacterial plasticity. Stable L-forms can multiply and propagate indefinitely in the absence of a cell wall. Data presented here are consistent with the model that intracellular vesicles in Listeria monocytogenes L-form cells represent the actual viable reproductive elements. First, small intracellular vesicles are formed along the mother cell cytoplasmic membrane, originating from local phospholipid accumulation. During growth, daughter vesicles incorporate a small volume of the cellular cytoplasm, and accumulate within volume-expanding mother cells. Confocal Raman microspectroscopy demonstrated the presence of nucleic acids and proteins in all intracellular vesicles, but only a fraction of which reveals metabolic activity. Following collapse of the mother cell and release of the daughter vesicles, they can establish their own membrane potential required for respiratory and metabolic processes. Premature depolarization of the surrounding membrane promotes activation of daughter cell metabolism prior to release. Based on genome resequencing of L-forms and comparison to the parental strain, we found no evidence for predisposing mutations that might be required for L-form transition. Further investigations revealed that propagation by intracellular budding not only occurs in Listeria species, but also in L-form cells generated from different Enterococcus species. From a more general viewpoint, this type of multiplication mechanism seems reminiscent of the physicochemical self-reproducing properties of abiotic lipid vesicles used to study the primordial reproduction pathways of putative prokaryotic precursor cells. PMID:22701656

  5. Efficient intracellular delivery and improved biocompatibility of colloidal silver nanoparticles towards intracellular SERS immuno-sensing.

    PubMed

    Bhardwaj, Vinay; Srinivasan, Supriya; McGoron, Anthony J

    2015-06-21

    High throughput intracellular delivery strategies, electroporation, passive and TATHA2 facilitated diffusion of colloidal silver nanoparticles (AgNPs) are investigated for cellular toxicity and uptake using state-of-art analytical techniques. The TATHA2 facilitated approach efficiently delivered high payload with no toxicity, pre-requisites for intracellular applications of plasmonic metal nanoparticles (PMNPs) in sensing and therapeutics. PMID:25939798

  6. Esterified Trityl Radicals as Intracellular Oxygen Probes

    PubMed Central

    Liu, Yangping; Villamena, Frederick A.; Sun, Jian; Wang, Tse-yao

    2009-01-01

    Triarylmethyl (trityl) radicals exhibit high stability and narrow line width at physiological conditions which provide high sensitivity and resolution for the measurement of O2 concentration, making them attractive as EPR oximetry probes. However, the application of previously available compounds has been limited by their poor intracellular permeability. We recently reported the synthesis and characterization of esterified trityl radicals as potential intracellular EPR probes and their oxygen sensitivity, redox properties and enzyme-mediated hydrolysis were investigated. In this paper, we report the cellular permeability and stability of these trityls in the presence of bovine aortic endothelial cells. Results show that the acetoxymethoxycarbonyl-containing trityl AMT-02 exhibits high stability in the presence of cells and can be effectively internalized. The intracellular hydrolysis of AMT-02 to the carboxylate form of the trityl (CT-03) was also observed. In addition, this internalized trityl probe was applied to measure intracellular O2 concentrations and the effects of menadione and KCN on the rates of O2 consumption in endothelial cells. This study demonstrates that these esterified trityl radicals can function as effective EPR oximetry probes measuring intracellular O2 concentration and consumption. PMID:19135524

  7. Chlamydia Pneumoniae CdsL Regulates CdsN ATPase Activity, and Disruption with a Peptide Mimetic Prevents Bacterial Invasion.

    PubMed

    Stone, Chris B; Bulir, David C; Emdin, Connor A; Pirie, Ryan M; Porfilio, Elisa A; Slootstra, Jerry W; Mahony, James B

    2011-01-01

    Chlamydiae are obligate intracellular pathogens that likely require type III secretion (T3S) to invade cells and replicate intracellularly within a cytoplasmic vacuole called an inclusion body. Chlamydia pneumoniae possess a YscL ortholog, CdsL, that has been shown to interact with the T3S ATPase (CdsN). In this report we demonstrate that CdsL down-regulates CdsN enzymatic activity in a dose-dependent manner. Using Pepscan epitope mapping we identified two separate binding domains to which CdsL binds viz. CdsN(221-229) and CdsN(265-270). We confirmed the binding domains using a pull-down assay and showed that GST-CdsN(221-270), which encompasses these peptides, co-purified with His-CdsL. Next, we used orthology modeling based on the crystal structure of a T3S ATPase ortholog from Escherichia coli, EscN, to map the binding domains on the predicted 3D structure of CdsN. The CdsL binding domains mapped to the catalytic domain of the ATPase, one in the central channel of the ATPase hexamer and one on the outer face. Since peptide mimetics have been used to disrupt essential protein interactions of the chlamydial T3S system and inhibit T3S-mediated invasion of HeLa cells, we hypothesized that if CdsL-CdsN binding is essential for regulating T3S then a CdsN peptide mimetic could be used to potentially block T3S and chlamydial invasion. Treatment of elementary body with a CdsN peptide mimetic inhibited C. pneumoniae invasion into HeLa cells in a dose-dependent fashion. This report represents the first use of Pepscan technology to identify binding domains for specific T3S proteins viz. CdsL on the ATPase, CdsN, and demonstrates that peptide mimetics can be used as anti-virulence factors to block bacterial invasion. PMID:21687413

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

    PubMed Central

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

    2008-01-01

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

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

    PubMed Central

    Wing, Boswell A.; Halevy, Itay

    2014-01-01

    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

  10. Interaction between Burkholderia pseudomallei and Acanthamoeba Species Results in Coiling Phagocytosis, Endamebic Bacterial Survival, and Escape

    Microsoft Academic Search

    TIMOTHY J. J. INGLIS; PAUL RIGBY; TERRY A. ROBERTSON; NICHOLE S. DUTTON; MANDY HENDERSON; BARBARA J. CHANG

    2000-01-01

    Burkholderia pseudomallei causes melioidosis, a potentially fatal disease whose clinical outcomes include rapid- onset septicemia and relapsing and delayed-onset infections. Like other facultative intracellular bacterial patho- gens, B. pseudomallei is capable of survival in human phagocytic cells, but unlike mycobacteria, Listeria monocytogenes, and Salmonella serovar Typhimurium, the species has not been reported to survive as an endosymbiont in free-living amebae.

  11. 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

  12. 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.

  13. 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

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

    Microsoft Academic Search

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

    2009-01-01

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

  15. Neutrophil recognition of bacterial DNA and Toll-like receptor 9-dependent and -independent regulation of neutrophil function

    Microsoft Academic Search

    Driss El Kebir; Levente József; János G. Filep

    2008-01-01

    Neutrophils are essential for host defense and detect the presence of invading microorganisms through recognition of pathogen-associated\\u000a molecular patterns. Among these receptors are Toll-like receptors (TLRs). Neutrophils express all known TLRs except for TLR3.\\u000a TLR9, localized intracellularly, is to date the best characterized sensor for bacterial DNA, containing short sequences of\\u000a unmethylated CpG motifs, though TLR9-independent intracellular DNA recognition mechanism(s)

  16. Facultative and obligate slavery in formicine ants: frequency of slavery, and proportion and size of slaves

    Microsoft Academic Search

    RIITTA SAVOLAINEN; RICHARD J. DESLIPPE

    1996-01-01

    Slave-making ants raid nests of other ant species, capture the developing offspring and rear them to slave workers. Here we compare slave-making of three formicine slave-making ants: the facultativeFormica subnuda, the obligatePolyergus breviceps, andF. subintegrawhich previously has been considered facultative but appears to be an obligate slave-making ant. IfF. subintegrais an obligate slavemaker, slave-making ofF. subintegrashould differ from that ofF.

  17. Mechanisms of bacterial pathogenicity

    PubMed Central

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

    2002-01-01

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

  18. Bacterial challenges in food

    PubMed Central

    Collee, J. G.

    1974-01-01

    Qualitative and quantitative aspects of bacterial challenges that might be encountered in food are discussed with reference to recognized and relatively unrecognized hazards. Mechanisms of pathogenicity are reviewed and the populations at risk are noted. The bacterial content of food as it is served at table merits more study. The challenge of prevention by education is discussed. Indirect bacterial challenges in our food are considered. The real challenge of diagnosis depends upon an awareness of a complex range of conditions; the importance of effective communication with efficient laboratory and epidemiological services is stressed. There is an increasing need for care in the preparation and distribution of food. PMID:4467860

  19. 25 CFR 163.42 - Obligated service and breach of contract.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...DEPARTMENT OF THE INTERIOR LAND AND WATER GENERAL FORESTRY REGULATIONS Forestry Education, Education Assistance, Recruitment...Obligated service. (1) Individuals completing forestry education programs with an...

  20. 41 CFR 102-85.65 - How does an OA obligate the customer agency?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...and Property Management Federal Property Management Regulations System...Continued) FEDERAL MANAGEMENT REGULATION ...OCCUPANCY IN GSA SPACE Occupancy Agreement...the customer agency? An OA obligates...appropriations...

  1. 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

  2. Intracellular pH, intracellular free Ca, and junctional cell-cell coupling

    Microsoft Academic Search

    Birgit Rose; Roger Rick

    1978-01-01

    Summary Intracellular pH (pHi) and intracellular Ca2+ ([Ca2+]i) were determined inChironomus salivary gland cells under various conditions of induced uncoupling. pHi was measured with aThomas-type microelectrode, changes in [Ca2+]i and their spatial distribution inside the cell were determined with the aid of intracellularly injected aequorin and an image intensifier-TV system, and cell-to-cell coupling was measured electrically. Treatments with NaCN (5mm),

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

    E-print Network

    Walker, Lawrence R.

    iron mineral crystals called magnetosomes which cause the cells to orient along the Earth's geomagnetic that biomineralize magnetosomes which are intracellular, membrane- bounded magnetic iron mineral crystals. The focus with either Casamino Acids or Yeast Extract as a sulfur source). Sulfide (as FeS: high [Fe] was used as a trap

  4. Intracellular Dynamic Response Characteristics of Pineal Photoreceptors

    Microsoft Academic Search

    Y. Morit; K. Segi; M. Samejima; T. Nakamura

    1984-01-01

    The dynamic properties of single pineal photoreceptors of Lampetra japonica were measured intracellularly by sinusoidal modulated light stimuli. According to the Bode plots the response amplitude and phase characteristic of pineal photoreceptors could be simulated by a linear model with 4th-order transfer function. A similarity to the receptor response of the vertebrate lateral eye was observed.

  5. Microfluidics for bacterial chemotaxis

    E-print Network

    Ahmed, Tanvir, Ph. D. Massachusetts Institute of Technology

    2011-01-01

    Bacterial chemotaxis, a remarkable behavioral trait which allows bacteria to sense and respond to chemical gradients in the environment, has implications in a broad range of fields including but not limited to disease ...

  6. Asphalt Showing Bacterial Degeneration 

    E-print Network

    Unknown

    2011-08-17

    Widely considered in the medical field as the last of the golden anti-microbial drugs, fluorinated quinolones provide a "last defense" for the attack on bacterial infections. The drugs are useful for treating gram negative and some gram positive...

  7. Bacterial Nasal Infections

    MedlinePLUS

    ... Version Ear, Nose, and Throat Disorders Nose and Sinus Disorders Bacterial Nasal Infections Nasal vestibulitis Nasal furuncles ... Version DOCTORS: Go to Professional Version Nose and Sinus Disorders Introduction to Nose and Sinus Disorders Deviated ...

  8. Growth of Bacterial Colonies

    NASA Astrophysics Data System (ADS)

    Warren, Mya; Hwa, Terence

    2013-03-01

    On hard agar gel, there is insufficient surface hydration for bacteria to swim or swarm. Instead, growth occurs in colonies of close-packed cells, which expand purely due to repulsive interactions: individual bacteria push each other out of the way through the force of their growth. In this way, bacterial colonies represent a new type of ``active'' granular matter. In this study, we investigate the physical, biochemical, and genetic elements that determine the static and dynamic aspects of this mode of bacterial growth for E. coli. We characterize the process of colony expansion empirically, and use discrete and continuum models to examine the extent to which our observations can be explained by the growth characteristics of non-communicating cells, coupled together by physical forces, nutrients, and waste products. Our results challenge the commonly accepted modes of bacterial colony growth and provide insight into sources of growth limitation in crowded bacterial communities.

  9. Physical Features of Intracellular Proteins that Moonlight on the Cell Surface

    PubMed Central

    Amblee, Vaishak; Jeffery, Constance J.

    2015-01-01

    Moonlighting proteins comprise a subset of multifunctional proteins that perform two or more biochemical functions that are not due to gene fusions, multiple splice variants, proteolytic fragments, or promiscuous enzyme activities. The project described herein focuses on a sub-set of moonlighting proteins that have a canonical biochemical function inside the cell and perform a second biochemical function on the cell surface in at least one species. The goal of this project is to consider the biophysical features of these moonlighting proteins to determine whether they have shared characteristics or defining features that might suggest why these particular proteins were adopted for a second function on the cell surface, or if these proteins resemble typical intracellular proteins. The latter might suggest that many other normally intracellular proteins found on the cell surface might also be moonlighting in this fashion. We have identified 30 types of proteins that have different functions inside the cell and on the cell surface. Some of these proteins are found to moonlight on the surface of multiple species, sometimes with different extracellular functions in different species, so there are a total of 98 proteins in the study set. Although a variety of intracellular proteins (enzymes, chaperones, etc.) are observed to be re-used on the cell surface, for the most part, these proteins were found to have physical characteristics typical of intracellular proteins. Many other intracellular proteins have also been found on the surface of bacterial pathogens and other organisms in proteomics experiments. It is quite possible that many of those proteins also have a moonlighting function on the cell surface. The increasing number and variety of known moonlighting proteins suggest that there may be more moonlighting proteins than previously thought, and moonlighting might be a common feature of many more proteins. PMID:26110848

  10. Intracellular Gene Expression Profile of Listeria monocytogenes †

    PubMed Central

    Chatterjee, Som Subhra; Hossain, Hamid; Otten, Sonja; Kuenne, Carsten; Kuchmina, Katja; Machata, Silke; Domann, Eugen; Chakraborty, Trinad; Hain, Torsten

    2006-01-01

    Listeria monocytogenes is a gram-positive, food-borne microorganism responsible for invasive infections with a high overall mortality. L. monocytogenes is among the very few microorganisms that can induce uptake into the host cell and subsequently enter the host cell cytosol by breaching the vacuolar membrane. We infected the murine macrophage cell line P388D1 with L. monocytogenes strain EGD-e and examined the gene expression profile of L. monocytogenes inside the vacuolar and cytosolic environments of the host cell by using whole-genome microarray and mutant analyses. We found that ?17% of the total genome was mobilized to enable adaptation for intracellular growth. Intracellularly expressed genes showed responses typical of glucose limitation within bacteria, with a decrease in the amount of mRNA encoding enzymes in the central metabolism and a temporal induction of genes involved in alternative-carbon-source utilization pathways and their regulation. Adaptive intracellular gene expression involved genes that are associated with virulence, the general stress response, cell division, and changes in cell wall structure and included many genes with unknown functions. A total of 41 genes were species specific, being absent from the genome of the nonpathogenic Listeria innocua CLIP 11262 strain. We also detected 25 genes that were strain specific, i.e., absent from the genome of the previously sequenced L. monocytogenes F2365 serotype 4b strain, suggesting heterogeneity in the gene pool required for intracellular survival of L. monocytogenes in host cells. Overall, our study provides crucial insights into the strategy of intracellular survival and measures taken by L. monocytogenes to escape the host cell responses. PMID:16428782

  11. The complete genome of Teredinibacter turnerae T7901: an intracellular endosymbiont of marine wood-boring bivalves (shipworms).

    PubMed

    Yang, Joyce C; Madupu, Ramana; Durkin, A Scott; Ekborg, Nathan A; Pedamallu, Chandra S; Hostetler, Jessica B; Radune, Diana; Toms, Bradley S; Henrissat, Bernard; Coutinho, Pedro M; Schwarz, Sandra; Field, Lauren; Trindade-Silva, Amaro E; Soares, Carlos A G; Elshahawi, Sherif; Hanora, Amro; Schmidt, Eric W; Haygood, Margo G; Posfai, Janos; Benner, Jack; Madinger, Catherine; Nove, John; Anton, Brian; Chaudhary, Kshitiz; Foster, Jeremy; Holman, Alex; Kumar, Sanjay; Lessard, Philip A; Luyten, Yvette A; Slatko, Barton; Wood, Nicole; Wu, Bo; Teplitski, Max; Mougous, Joseph D; Ward, Naomi; Eisen, Jonathan A; Badger, Jonathan H; Distel, Daniel L

    2009-01-01

    Here we report the complete genome sequence of Teredinibacter turnerae T7901. T. turnerae is a marine gamma proteobacterium that occurs as an intracellular endosymbiont in the gills of wood-boring marine bivalves of the family Teredinidae (shipworms). This species is the sole cultivated member of an endosymbiotic consortium thought to provide the host with enzymes, including cellulases and nitrogenase, critical for digestion of wood and supplementation of the host's nitrogen-deficient diet. T. turnerae is closely related to the free-living marine polysaccharide degrading bacterium Saccharophagus degradans str. 2-40 and to as yet uncultivated endosymbionts with which it coexists in shipworm cells. Like S. degradans, the T. turnerae genome encodes a large number of enzymes predicted to be involved in complex polysaccharide degradation (>100). However, unlike S. degradans, which degrades a broad spectrum (>10 classes) of complex plant, fungal and algal polysaccharides, T. turnerae primarily encodes enzymes associated with deconstruction of terrestrial woody plant material. Also unlike S. degradans and many other eubacteria, T. turnerae dedicates a large proportion of its genome to genes predicted to function in secondary metabolism. Despite its intracellular niche, the T. turnerae genome lacks many features associated with obligate intracellular existence (e.g. reduced genome size, reduced %G+C, loss of genes of core metabolism) and displays evidence of adaptations common to free-living bacteria (e.g. defense against bacteriophage infection). These results suggest that T. turnerae is likely a facultative intracellular ensosymbiont whose niche presently includes, or recently included, free-living existence. As such, the T. turnerae genome provides insights into the range of genomic adaptations associated with intracellular endosymbiosis as well as enzymatic mechanisms relevant to the recycling of plant materials in marine environments and the production of cellulose-derived biofuels. PMID:19568419

  12. The Aggregation-Prone Intracellular Serpin SRP-2 Fails to Transit the ER in Caenorhabditis elegans.

    PubMed

    Silverman, Richard M; Cummings, Erin E; O'Reilly, Linda P; Miedel, Mark T; Silverman, Gary A; Luke, Cliff J; Perlmutter, David H; Pak, Stephen C

    2015-05-01

    Familial encephalopathy with neuroserpin inclusions bodies (FENIB) is a serpinopathy that induces a rare form of presenile dementia. Neuroserpin contains a classical signal peptide and like all extracellular serine proteinase inhibitors (serpins) is secreted via the endoplasmic reticulum (ER)-Golgi pathway. The disease phenotype is due to gain-of-function missense mutations that cause neuroserpin to misfold and aggregate within the ER. In a previous study, nematodes expressing a homologous mutation in the endogenous Caenorhabditis elegans serpin, srp-2, were reported to model the ER proteotoxicity induced by an allele of mutant neuroserpin. Our results suggest that SRP-2 lacks a classical N-terminal signal peptide and is a member of the intracellular serpin family. Using confocal imaging and an ER colocalization marker, we confirmed that GFP-tagged wild-type SRP-2 localized to the cytosol and not the ER. Similarly, the aggregation-prone SRP-2 mutant formed intracellular inclusions that localized to the cytosol. Interestingly, wild-type SRP-2, targeted to the ER by fusion to a cleavable N-terminal signal peptide, failed to be secreted and accumulated within the ER lumen. This ER retention phenotype is typical of other obligate intracellular serpins forced to translocate across the ER membrane. Neuroserpin is a secreted protein that inhibits trypsin-like proteinase. SRP-2 is a cytosolic serpin that inhibits lysosomal cysteine peptidases. We concluded that SRP-2 is neither an ortholog nor a functional homolog of neuroserpin. Furthermore, animals expressing an aggregation-prone mutation in SRP-2 do not model the ER proteotoxicity associated with FENIB. PMID:25786854

  13. Sensing Cytosolic RpsL by Macrophages Induces Lysosomal Cell Death and Termination of Bacterial Infection

    PubMed Central

    Quick, Marsha L.; Joyce, Johanna A.; Qu, Jie-Ming; Luo, Zhao-Qing

    2015-01-01

    The intracellular bacterial pathogen Legionella pneumophila provokes strong host responses and has proven to be a valuable model for the discovery of novel immunosurveillance pathways. Our previous work revealed that an environmental isolate of L. pneumophila induces a noncanonical form of cell death, leading to restriction of bacterial replication in primary mouse macrophages. Here we show that such restriction also occurs in infections with wild type clinical isolates. Importantly, we found that a lysine to arginine mutation at residue 88 (K88R) in the ribosome protein RpsL that not only confers bacterial resistance to streptomycin, but more importantly, severely attenuated the induction of host cell death and enabled L. pneumophila to replicate in primary mouse macrophages. Although conferring similar resistance to streptomycin, a K43N mutation in RpsL does not allow productive intracellular bacterial replication. Further analysis indicated that RpsL is capable of effectively inducing macrophage death via a pathway involved in lysosomal membrane permeabilization; the K88R mutant elicits similar responses but is less potent. Moreover, cathepsin B, a lysosomal protease that causes cell death after being released into the cytosol upon the loss of membrane integrity, is required for efficient RpsL-induced macrophage death. Furthermore, despite the critical role of cathepsin B in delaying RpsL-induced cell death, macrophages lacking cathepsin B do not support productive intracellular replication of L. pneumophila harboring wild type RpsL. This suggests the involvement of other yet unidentified components in the restriction of bacterial replication. Our results identified RpsL as a regulator in the interactions between bacteria such as L. pneumophila and primary mouse macrophages by triggering unique cellular pathways that restrict intracellular bacterial replication. PMID:25738962

  14. Codominance of Lactobacillus plantarum and obligate heterofermentative lactic acid bacteria during sourdough fermentation.

    PubMed

    Ventimiglia, Giusi; Alfonzo, Antonio; Galluzzo, Paola; Corona, Onofrio; Francesca, Nicola; Caracappa, Santo; Moschetti, Giancarlo; Settanni, Luca

    2015-10-01

    Fifteen sourdoughs produced in western Sicily (southern Italy) were analysed by classical methods for their chemico-physical characteristics and the levels of lactic acid bacteria (LAB). pH and total titratable acidity (TTA) were mostly in the range commonly reported for similar products produced in Italy, but the fermentation quotient (FQ) of the majority of samples was above 4.0, due to the low concentration of acetic acid estimated by high performance liquid chromatography (HPLC). Specific counts of LAB showed levels higher than 10(8) CFU g(-1) for many samples. The colonies representing various morphologies were isolated and, after the differentiation based on phenotypic characteristics, divided into 10 groups. The most numerous group was composed of facultative heterofermentative isolates, indicating a relevance of this bacterial group during fermentation. The genetic analysis by randomly amplified polymorphic DNA (RAPD)-PCR, 16S rRNA gene sequencing and species-specific PCRs identified 33 strains as Lactobacillus plantarum, Lactobacillus curvatus and Lactobacillus graminis. Due to the consistent presence of L. plantarum, it was concluded that this species codominates with obligate heterofermentative LAB in sourdough production in this geographical area. In order to evaluate the performances at the basis of their fitness, the 29 L. plantarum strains were investigated for several technological traits. Twelve cultures showed good acidifying abilities in vitro and L. plantarum PON100148 produced the highest concentrations of organic acids. Eleven strains were positive for extracellular protease activity. Bacteriocin-like inhibitory substances (BLIS) production and antifungal activity was scored positive for several strains, included L. plantarum PON100148 which was selected as starter for experimental sourdough production. The characteristics of the sourdoughs and the resulting breads indicated that the best productions were obtained in presence of L. plantarum PON100148. PMID:26187828

  15. Interaction of Interferon Gamma-Induced Reactive Oxygen Species with Ceftazidime Leads to Synergistic Killing of Intracellular Burkholderia pseudomallei

    PubMed Central

    Mosovsky, Kara; Silva, Ediane; Troyer, Ryan; Propst-Graham, Katie

    2014-01-01

    Burkholderia pseudomallei, a facultative intracellular pathogen, causes severe infections and is inherently refractory to many antibiotics. Previous studies from our group have shown that interferon gamma (IFN-?) interacts synergistically with the antibiotic ceftazidime to kill bacteria in infected macrophages. The present study aimed to identify the underlying mechanism of that interaction. We first showed that blocking reactive oxygen species (ROS) pathways reversed IFN-?- and ceftazidime-mediated killing, which led to our hypothesis that IFN-?-induced ROS interacted with ceftazidime to synergistically kill Burkholderia bacteria. Consistent with this hypothesis, we also observed that buthionine sulfoximine (BSO), another inducer of ROS, could substitute for IFN-? to similarly potentiate the effect of ceftazidime on intracellular killing. Next, we observed that IFN-? induced ROS-mediated killing of intracellular but not extracellular bacteria. On the other hand, ceftazidime effectively reduced extracellular bacteria but was not capable of intracellular killing when applied at 10 ?g/ml. We investigated the exact role of IFN-?-induced ROS responses on intracellular bacteria and notably observed a lack of actin polymerization associated with Burkholderia bacteria in IFN-?-treated macrophages, which led to our finding that IFN-?-induced ROS blocks vacuolar escape. Based on these results, we propose a model in which synergistically reduced bacterial burden is achieved primarily through separate and compartmentalized killing: intracellular killing by IFN-?-induced ROS responses and extracellular killing by ceftazidime. Our findings suggest a means of enhancing antibiotic activity against Burkholderia bacteria through combination with drugs that induce ROS pathways or otherwise target intracellular spread and/or replication of bacteria. PMID:25070108

  16. 26 CFR 1.662(a)-4 - Amounts used in discharge of a legal obligation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...income of a trust in case of divorce, etc.) applies. The term...resources. For example, a parent has a “legal obligation...his support so long as his parent is able to support him...is obligated to support his parent only if the parent's...

  17. 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…

  18. Obligation and Motivation: Obstacles and Resources for Counselor Well-Being and Effectiveness.

    ERIC Educational Resources Information Center

    Day, James M.

    1994-01-01

    Considers the role of obligation in counselors' motivation to do their work. Observes that narrative practices related to the humanities, and to religious and spiritual traditions, may help counselors when obligation-based motivation is overwhelmed by the harsher elements of human nature and of the counseling profession. (RJM)

  19. 34 CFR 76.709 - Funds may be obligated during a “carryover period.”

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    (a) If a State or a subgrantee does not obligate all of its grant or subgrant funds by the end of the fiscal year for which Congress appropriated the funds, it may obligate the remaining funds during a carryover period of one additional fiscal...

  20. 27 CFR 44.122 - Deposits of bonds, notes, or obligations in lieu of corporate surety.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...bonds, notes, or obligations in lieu of corporate surety. 44.122 Section 44.122...bonds, notes, or obligations in lieu of corporate surety. Bonds or notes of the...cover his operations, in lieu of the corporate surety, in accordance with the...

  1. 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...

  2. 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…

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 20 CFR 655.1306 - Assurances and obligations of H-2A Labor Contractors.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Assurances and obligations of H-2A Labor Contractors. 655.1306 Section 655.1306 Employees' Benefits EMPLOYMENT AND TRAINING...Employment in the United States (H-2A Workers) § 655.1306 Assurances and obligations of H-2A...

  8. 20 CFR 655.1306 - Assurances and obligations of H-2A Labor Contractors.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...Assurances and obligations of H-2A Labor Contractors. 655.1306 Section 655.1306 Employees' Benefits EMPLOYMENT AND TRAINING...Employment in the United States (H-2A Workers) § 655.1306 Assurances and obligations of H-2A...

  9. 20 CFR 655.1306 - Assurances and obligations of H-2A Labor Contractors.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...Assurances and obligations of H-2A Labor Contractors. 655.1306 Section 655.1306 Employees' Benefits EMPLOYMENT AND TRAINING...Employment in the United States (H-2A Workers) § 655.1306 Assurances and obligations of H-2A...

  10. 20 CFR 655.1306 - Assurances and obligations of H-2A Labor Contractors.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...Assurances and obligations of H-2A Labor Contractors. 655.1306 Section 655.1306 Employees' Benefits EMPLOYMENT AND TRAINING...Employment in the United States (H-2A Workers) § 655.1306 Assurances and obligations of H-2A...

  11. 20 CFR 655.22 - Obligations of H-2B employers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Obligations of H-2B employers. 655.22 Section 655.22 Employees' Benefits EMPLOYMENT AND TRAINING...Registered Nursing in the United States (H-2B Workers) § 655.22 Obligations of H-2B employers. An...

  12. 20 CFR 655.1306 - Assurances and obligations of H-2A Labor Contractors.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...Assurances and obligations of H-2A Labor Contractors. 655.1306 Section 655.1306 Employees' Benefits EMPLOYMENT AND TRAINING...Employment in the United States (H-2A Workers) § 655.1306 Assurances and obligations of H-2A...

  13. 26 CFR 1.166-10 - Reserve for guaranteed debt obligations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...obligations. (a) Definitions. The following...repossessed property in satisfaction of the debt obligations...that property and the customer with respect to that...in property and the customer with respect to the...television set to B, his customer. If at the...

  14. Pebbles in a Pond: Learner, Teacher, and Policy Perspectives on Mutual Obligation.

    ERIC Educational Resources Information Center

    Adult Literacy and Numeracy Australian Research Consortium, Melbourne (Victoria). Victorian Centre.

    This book contains nine chapters, by various authors, containing research and policy perspectives on issues of mutual obligation between teachers and students, especially in Australia. The following are included: (1) "Researching Literacy, Language, and Numeracy and Mutual Obligation: An Introduction to Some Issues" (Sheilagh Kelly and Liz…

  15. 42 CFR 68.15 - When can an NIH LRP payment obligation be discharged in bankruptcy?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false When can an NIH LRP payment obligation be discharged in bankruptcy...TRAINING NATIONAL INSTITUTES OF HEALTH (NIH) LOAN REPAYMENT PROGRAMS (LRPs) § 68.15 When can an NIH LRP payment obligation be discharged in...

  16. 42 CFR 68.15 - When can an NIH LRP payment obligation be discharged in bankruptcy?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false When can an NIH LRP payment obligation be discharged in bankruptcy...TRAINING NATIONAL INSTITUTES OF HEALTH (NIH) LOAN REPAYMENT PROGRAMS (LRPs) § 68.15 When can an NIH LRP payment obligation be discharged in...

  17. 40 CFR 80.1406 - Who is an obligated party under the RFS program?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION...obligated party under the RFS program? (a)(1) An obligated...opt-in to the renewable fuel program under the provisions in § 80...b) of this section in the aggregate for all of the refineries...

  18. 36 CFR 1239.26 - What are an agency's follow up obligations for an inspection report?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... false What are an agency's follow up obligations for an inspection report...1239.26 What are an agency's follow up obligations for an inspection report...transmission of the final report. NARA may take up to 60 days to review and comment on...

  19. 36 CFR 1239.26 - What are an agency's follow up obligations for an inspection report?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... false What are an agency's follow up obligations for an inspection report...1239.26 What are an agency's follow up obligations for an inspection report...transmission of the final report. NARA may take up to 60 days to review and comment on...

  20. 36 CFR 1239.26 - What are an agency's follow up obligations for an inspection report?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... false What are an agency's follow up obligations for an inspection report...1239.26 What are an agency's follow up obligations for an inspection report...transmission of the final report. NARA may take up to 60 days to review and comment on...

  1. 36 CFR 1239.26 - What are an agency's follow up obligations for an inspection report?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... false What are an agency's follow up obligations for an inspection report...1239.26 What are an agency's follow up obligations for an inspection report...transmission of the final report. NARA may take up to 60 days to review and comment on...

  2. 36 CFR 1239.26 - What are an agency's follow up obligations for an inspection report?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2012-07-01 true What are an agency's follow up obligations for an inspection report...1239.26 What are an agency's follow up obligations for an inspection report...transmission of the final report. NARA may take up to 60 days to review and comment on...

  3. 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

  4. Obligation for Role based Access Control Gansen Zhao, David Chadwick, Sassa Otenko

    E-print Network

    Kent, University of

    a design of the augmentation of obligations in the context of RBAC standard. The design is then further consolidated in the PERMIS RBAC authorization infrastructure. Details of incorporating obligations into the PERMIS RBAC authorization infrastructure are given. This paper also discusses the possible nondeterminism

  5. Brucella Intracellular Life Relies on the Transmembrane Protein CD98 Heavy Chain.

    PubMed

    Keriel, Anne; Botella, Eric; Estrach, Soline; Bragagnolo, Gabriel; Vergunst, Annette C; Feral, Chloe C; O'Callaghan, David

    2015-06-01

    Brucella are intracellular bacterial pathogens that use a type IV secretion system (T4SS) to escape host defenses and create a niche in which they can multiply. Although the importance of Brucella T4SS is clear, little is known about its interactions with host cell structures. In this study, we identified the eukaryotic protein CD98hc as a partner for Brucella T4SS subunit VirB2. This transmembrane glycoprotein is involved in amino acid transport, modulation of integrin signaling, and cell-to-cell fusion. Knockdown of CD98hc expression in HeLa cells demonstrated that it is essential for Brucella infection. Using knockout dermal fibroblasts, we confirmed its role for Brucella but found that it is not required for Salmonella infection. CD98hc transiently accumulates around the bacteria during the early phases of infection and is required for both optimal bacterial uptake and intracellular multiplication of Brucella. These results provide new insights into the complex interplay between Brucella and its host. PMID:25505297

  6. Mechanisms of Francisella tularensis Intracellular Pathogenesis

    PubMed Central

    Celli, Jean

    2013-01-01

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

  7. Intracellular diffusion restrictions in isolated cardiomyocytes from rainbow trout

    Microsoft Academic Search

    Niina Sokolova; Marko Vendelin; Rikke Birkedal

    2009-01-01

    BACKGROUND: Restriction of intracellular diffusion of adenine nucleotides has been studied intensively on adult rat cardiomyocytes. However, their cause and role in vivo is still uncertain. Intracellular membrane structures have been suggested to play a role. We therefore chose to study cardiomyocytes from rainbow trout (Oncorhynchus mykiss), which are thinner and have fewer intracellular membrane structures than adult rat cardiomyocytes.

  8. Biocide susceptibility and intracellular glutathione in Escherichia coli

    Microsoft Academic Search

    John S. Chapman; Megan A. Diehl; Richard C. Lyman

    1993-01-01

    Summary Inhibition of growth and speed of kill by biocides with different mechanisms of action was examined with respect to intracellular glutathione levels. strain deficient in intracellular glutathione was hypersusceptible to electrophilic biocides, with the exception of an isothiazolone biocide. Growth inhibition by quaternary ammonium compounds and radical-generating biocides was unaffected by intracellular glutathione levels. Speed of kill experiments demonstrated

  9. Interaction of intracellular amyloid peptide with chaperone proteins

    Microsoft Academic Search

    Virginia Fonte; Vadim Kapulkin; Andrew Taft; Amy Fluet; David Friedman; Christopher D. Link

    2002-01-01

    Expression of the human amyloid peptide (A) in transgenic Caenorhabditis elegans animals can lead to the formation of intracellular immunoreactive deposits as well as the formation of intracellular amyloid. We have used this model to identify proteins that interact with intracellular A in vivo. Mass spectrometry analysis of proteins that specifically coimmunoprecipitate with A has identified six likely chaperone proteins:

  10. Integrating chemical and genetic silencing strategies to identify host kinase-phosphatase inhibitor networks that control bacterial infection.

    PubMed

    Albers, Harald M H G; Kuijl, Coenraad; Bakker, Jeroen; Hendrickx, Loes; Wekker, Sharida; Farhou, Nadha; Liu, Nora; Blasco-Moreno, Bernat; Scanu, Tiziana; den Hertog, Jeroen; Celie, Patrick; Ovaa, Huib; Neefjes, Jacques

    2014-02-21

    Every year three million people die as a result of bacterial infections, and this number may further increase due to resistance to current antibiotics. These antibiotics target almost all essential bacterial processes, leaving only a few new targets for manipulation. The host proteome has many more potential targets for manipulation in order to control bacterial infection, as exemplified by the observation that inhibiting the host kinase Akt supports the elimination of different intracellular bacteria including Salmonella and M. tuberculosis. If host kinases are involved in the control of bacterial infections, phosphatases could be as well. Here we present an integrated small interference RNA and small molecule screen to identify host phosphatase-inhibitor combinations that control bacterial infection. We define host phosphatases inhibiting intracellular growth of Salmonella and identify corresponding inhibitors for the dual specificity phosphatases DUSP11 and 27. Pathway analysis places many kinases and phosphatases controlling bacterial infection in an integrated pathway centered around Akt. This network controls host cell metabolism, survival, and growth and bacterial survival and reflect a natural host cell response to bacterial infection. Inhibiting two enzyme classes with opposite activities-kinases and phosphatases-may be a new strategy to overcome infections by antibiotic-resistant bacteria. PMID:24274083

  11. Genetic regulation of resistance to intracellular pathogens

    Microsoft Academic Search

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

    1982-01-01

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

  12. A practical approach for intracellular protein delivery

    Microsoft Academic Search

    Claire O. Weill; Stéphanie Biri; Abdennaji Adib; Patrick Erbacher

    2008-01-01

    Protein delivery represents a powerful tool for experiments in live cells including studies of protein-protein interactions,\\u000a protein interference with blocking antibodies, intracellular trafficking and protein or peptide biological functions. Most\\u000a available reagents dedicated to the protein delivery allow efficient crossing of the plasma membrane. Nevertheless, the major\\u000a disadvantage for these reagents is a weak release of the delivered protein into

  13. Lysosomal Sequestration Determines Intracellular Imatinib Levels.

    PubMed

    Burger, Herman; den Dekker, Alexander T; Segeletz, Sandra; Boersma, Antonius W M; de Bruijn, Peter; Debiec-Rychter, Maria; Taguchi, Takahiro; Sleijfer, Stefan; Sparreboom, Alex; Mathijssen, Ron H J; Wiemer, Erik A C

    2015-09-01

    The intracellular uptake and retention (IUR) of imatinib is reported to be controlled by the influx transporter SLC22A1 (organic cation transporter 1). We recently hypothesized that alternative uptake and/or retention mechanisms exist that determine intracellular imatinib levels. Here, we systematically investigate the nature of these mechanisms. Imatinib uptake in cells was quantitatively determined by liquid chromatography-tandem mass spectrometry. Fluorescent microscopy was used to establish subcellular localization of imatinib. Immunoblotting, cell cycle analyses, and apoptosis assays were performed to evaluate functional consequences of imatinib sequestration. Uptake experiments revealed high intracellular imatinib concentrations in HEK293, the leukemic cell lines K562 and SD-1, and a gastrointestinal stromal tumor cell line GIST-T1. We demonstrated that imatinib IUR is time-, dose-, temperature-, and energy-dependent and provide evidence that SLC22A1 and other potential imatinib transporters do not substantially contribute to the IUR of imatinib. Prazosin, amantadine, NH4Cl, and the vacuolar ATPase inhibitor bafilomycin A1 significantly decreased the IUR of imatinib and likely interfere with lysosomal retention and accumulation of imatinib. Costaining experiments with LysoTracker Red confirmed lysosomal sequestration of imatinib. Inhibition of the lysosomal sequestration had no effect on the inhibition of c-Kit signaling and imatinib-mediated cell cycle arrest but significantly increased apoptosis in imatinib-sensitive GIST-T1 cells. We conclude that intracellular imatinib levels are primarily determined by lysosomal sequestration and do not depend on SLC22A1 expression. PMID:26108972

  14. Therapy of intracellular Staphylococcus aureus by tigecyclin

    PubMed Central

    2013-01-01

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

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

    PubMed Central

    Braymer, Joseph J.; Giedroc, David P.

    2014-01-01

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

  16. Intracellular replication of Mycobacterium marinum within Dictyostelium discoideum: efficient replication in the absence of host coronin.

    PubMed

    Solomon, Jonathan M; Leung, Grace S; Isberg, Ralph R

    2003-06-01

    Mycobacterium marinum causes tuberculosis-like disease in fish and amphibians and has been used as a model mycobacterial species because of its rapid growth and less stringent containment requirements relative to other mycobacterial species. We demonstrate here that M. marinum grows within Dictyostelium discoideum cells, allowing the genetic analysis of host factors that may modulate the replication of mycobacterial species. Intracellular growth of M. marinum was shown to mimic the properties previously observed for growth within cultured phagocytes. A defined bacterial mutant defective for growth within phagocytic cells was shown to be similarly defective for growth within D. discoideum. To test the role of host coronin, which was previously hypothesized to positively modulate mycobacterial growth within mouse macrophages, a defined D. discoideum coronin mutant was analyzed. Surprisingly, the absence of coronin resulted in enhanced intracellular replication of M. marinum relative to the control wild-type strain. Consistent with previous observations, some phagosomes showed persistence of coronin about the surface of the compartment, but colocalization of the protein was far from uniform. We conclude that in D. discoideum factors other than coronin support intracellular replication of M. marinum. PMID:12761143

  17. A novel intracellular nitrogen-fixing symbiosis made by Ustilago maydis and Bacillus spp.

    PubMed

    Ruiz-Herrera, José; León-Ramírez, Claudia; Vera-Nuñez, Antonio; Sánchez-Arreguín, Alejandro; Ruiz-Medrano, Roberto; Salgado-Lugo, Holjes; Sánchez-Segura, Lino; Peña-Cabriales, Juan José

    2015-08-01

    We observed that the maize pathogenic fungus Ustilago maydis grew in nitrogen (N)-free media at a rate similar to that observed in media containing ammonium nitrate, suggesting that it was able to fix atmospheric N2 . Because only prokaryotic organisms have the capacity to reduce N2 , we entertained the possibility that U. maydis was associated with an intracellular bacterium. The presence of nitrogenase in the fungus was analyzed by acetylene reduction, and capacity to fix N2 by use of (15) N2 . Presence of an intracellular N2 -fixing bacterium was analyzed by PCR amplification of bacterial 16S rRNA and nifH genes, and by microscopic observations. Nitrogenase activity and (15) N incorporation into the cells proved that U. maydis fixed N2 . Light and electron microscopy, and fluorescence in situ hybridization (FISH) experiments revealed the presence of intracellular bacteria related to Bacillus pumilus, as evidenced by sequencing of the PCR-amplified fragments. These observations reveal for the first time the existence of an endosymbiotic N2 -fixing association involving a fungus and a bacterium. PMID:25754368

  18. Quantification of the effects of antibodies on the extra- and intracellular dynamics of Salmonella enterica

    PubMed Central

    Restif, Olivier; Goh, Yun S.; Palayret, Matthieu; Grant, Andrew J.; McKinley, Trevelyan J.; Clark, Michael R.; Mastroeni, Pietro

    2013-01-01

    Antibodies are known to be essential in controlling Salmonella infection, but their exact role remains elusive. We recently developed an in vitro model to investigate the relative efficiency of four different human immunoglobulin G (IgG) subclasses in modulating the interaction of the bacteria with human phagocytes. Our results indicated that different IgG subclasses affect the efficacy of Salmonella uptake by human phagocytes. In this study, we aim to quantify the effects of IgG on intracellular dynamics of infection by combining distributions of bacterial numbers per phagocyte observed by fluorescence microscopy with a mathematical model that simulates the in vitro dynamics. We then use maximum likelihood to estimate the model parameters and compare them across IgG subclasses. The analysis reveals heterogeneity in the division rates of the bacteria, strongly suggesting that a subpopulation of intracellular Salmonella, while visible under the microscope, is not dividing. Clear differences in the observed distributions among the four IgG subclasses are best explained by variations in phagocytosis and intracellular dynamics. We propose and compare potential factors affecting the replication and death of bacteria within phagocytes, and we discuss these results in the light of recent findings on dormancy of Salmonella. PMID:23235264

  19. Bacterial avirulence genes.

    PubMed

    Leach, J E; White, F F

    1996-01-01

    Although more than 30 bacterial avirulence genes have been cloned and characterized, the function of the gene products in the elictitation of resistance is unknown in all cases but one. The product of avrD from Pseudomonas syringae pv. glycinea likely functions indirectly to elicit resistance in soybean, that is, evidence suggests the gene product is an enzyme involved in elicitor production. In most if not all cases, bacterial avirulence gene function is dependent on interactions with the hypersensitive response and pathogenicity (hrp) genes. Many hrp genes are similar to genes involved in delivery of pathogenicity factors in mammalian bacterial pathogens. Thus, analogies between mammalian and plant pathogens may provide needed clues to elucidate how virulence gene products control induction of resistance. PMID:15012539

  20. 20 CFR 667.275 - What are a recipient's obligations to ensure nondiscrimination and equal opportunity, and what...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    What are a recipient's obligations to ensure nondiscrimination and equal opportunity, and what are a recipient's obligations with respect to religious activities? 667.275 Section 667.275 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR...

  1. 20 CFR 667.275 - What are a recipient's obligations to ensure nondiscrimination and equal opportunity, and what...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    What are a recipient's obligations to ensure nondiscrimination and equal opportunity, and what are a recipient's obligations with respect to religious activities? 667.275 Section 667.275 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF...

  2. 20 CFR 667.275 - What are a recipient's obligations to ensure nondiscrimination and equal opportunity, and what...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    What are a recipient's obligations to ensure nondiscrimination and equal opportunity, and what are a recipient's obligations with respect to religious activities? 667.275 Section 667.275 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF...

  3. 40 CFR 124.13 - Obligation to raise issues and provide information during the public comment period.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    40 Protection of Environment 21 2010-07-01... Obligation to raise issues and provide information...124.13 Protection of Environment ENVIRONMENTAL PROTECTION... Obligation to raise issues and provide...

  4. 40 CFR 124.13 - Obligation to raise issues and provide information during the public comment period.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    40 Protection of Environment 22 2011-07-01... Obligation to raise issues and provide information...124.13 Protection of Environment ENVIRONMENTAL PROTECTION... Obligation to raise issues and provide...

  5. 26 CFR 1.103-6 - Interest upon United States obligations in the case of nonresident aliens and foreign...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...States obligations in the case of nonresident aliens...corporations, not engaged in business in the United States...States obligations in the case of nonresident aliens...corporations, not engaged in business in the United...

  6. 26 CFR 1.103-6 - Interest upon United States obligations in the case of nonresident aliens and foreign...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...States obligations in the case of nonresident aliens...corporations, not engaged in business in the United States...States obligations in the case of nonresident aliens...corporations, not engaged in business in the United...

  7. 26 CFR 1.103-6 - Interest upon United States obligations in the case of nonresident aliens and foreign...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...States obligations in the case of nonresident aliens...corporations, not engaged in business in the United States...States obligations in the case of nonresident aliens...corporations, not engaged in business in the United...

  8. 26 CFR 1.103-6 - Interest upon United States obligations in the case of nonresident aliens and foreign...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...States obligations in the case of nonresident aliens...corporations, not engaged in business in the United States...States obligations in the case of nonresident aliens...corporations, not engaged in business in the United...

  9. 26 CFR 1.103-6 - Interest upon United States obligations in the case of nonresident aliens and foreign...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...States obligations in the case of nonresident aliens...corporations, not engaged in business in the United States...States obligations in the case of nonresident aliens...corporations, not engaged in business in the United...

  10. 31 CFR 354.2 - Law governing rights and obligations of Federal Reserve Banks, and Sallie Mae; rights of any...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Law governing rights and obligations of Federal Reserve Banks, and Sallie Mae; rights of any Person against Federal Reserve...obligations of Federal Reserve Banks, and Sallie Mae; rights of any Person against Federal...

  11. 42 CFR 137.251. - What obligation does the retroceding Self-Governance Tribe have with respect to returning...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...obligation does the retroceding Self-Governance Tribe have with respect to...HUMAN SERVICES TRIBAL SELF-GOVERNANCE Retrocession § 137.251...obligation does the retroceding Self-Governance Tribe have with respect...

  12. 20 CFR 1002.261 - Who is responsible for funding any plan obligation to provide the employee with pension benefits?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...obligation to provide the employee with pension benefits? 1002.261 Section 1002...1994 Reemployment Rights and Benefits Pension Plan Benefits § 1002.261 Who is...obligation to provide the employee with pension benefits? With the exception of...

  13. 20 CFR 1002.261 - Who is responsible for funding any plan obligation to provide the employee with pension benefits?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...obligation to provide the employee with pension benefits? 1002.261 Section 1002...1994 Reemployment Rights and Benefits Pension Plan Benefits § 1002.261 Who is...obligation to provide the employee with pension benefits? With the exception of...

  14. 20 CFR 1002.266 - What are the obligations of a multiemployer pension benefit plan under USERRA?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...the obligations of a multiemployer pension benefit plan under USERRA? 1002...Reemployment Rights and Benefits Pension Plan Benefits § 1002.266 What are the obligations of a multiemployer pension benefit plan under USERRA? A...

  15. 20 CFR 1002.266 - What are the obligations of a multiemployer pension benefit plan under USERRA?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...the obligations of a multiemployer pension benefit plan under USERRA? 1002...Reemployment Rights and Benefits Pension Plan Benefits § 1002.266 What are the obligations of a multiemployer pension benefit plan under USERRA? A...

  16. 20 CFR 1002.266 - What are the obligations of a multiemployer pension benefit plan under USERRA?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...the obligations of a multiemployer pension benefit plan under USERRA? 1002...Reemployment Rights and Benefits Pension Plan Benefits § 1002.266 What are the obligations of a multiemployer pension benefit plan under USERRA? A...

  17. 20 CFR 1002.261 - Who is responsible for funding any plan obligation to provide the employee with pension benefits?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...obligation to provide the employee with pension benefits? 1002.261 Section 1002...1994 Reemployment Rights and Benefits Pension Plan Benefits § 1002.261 Who is...obligation to provide the employee with pension benefits? With the exception of...

  18. 20 CFR 1002.261 - Who is responsible for funding any plan obligation to provide the employee with pension benefits?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...obligation to provide the employee with pension benefits? 1002.261 Section 1002...1994 Reemployment Rights and Benefits Pension Plan Benefits § 1002.261 Who is...obligation to provide the employee with pension benefits? With the exception of...

  19. 20 CFR 1002.261 - Who is responsible for funding any plan obligation to provide the employee with pension benefits?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...obligation to provide the employee with pension benefits? 1002.261 Section 1002...1994 Reemployment Rights and Benefits Pension Plan Benefits § 1002.261 Who is...obligation to provide the employee with pension benefits? With the exception of...

  20. 20 CFR 1002.266 - What are the obligations of a multiemployer pension benefit plan under USERRA?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...the obligations of a multiemployer pension benefit plan under USERRA? 1002...Reemployment Rights and Benefits Pension Plan Benefits § 1002.266 What are the obligations of a multiemployer pension benefit plan under USERRA? A...

  1. 20 CFR 1002.266 - What are the obligations of a multiemployer pension benefit plan under USERRA?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...the obligations of a multiemployer pension benefit plan under USERRA? 1002...Reemployment Rights and Benefits Pension Plan Benefits § 1002.266 What are the obligations of a multiemployer pension benefit plan under USERRA? A...

  2. The LRR and RING Domain Protein LRSAM1 Is an E3 Ligase Crucial for Ubiquitin-Dependent Autophagy of Intracellular Salmonella Typhimurium

    PubMed Central

    Huett, Alan; Heath, Robert J.; Begun, Jakob; Sassi, Slim O.; Baxt, Leigh A.; Vyas, Jatin M.; Goldberg, Marcia B.; Xavier, Ramnik J.

    2013-01-01

    SUMMARY Several species of pathogenic bacteria replicate within an intracellular vacuolar niche. Bacteria that escape into the cytosol are captured by the autophagic pathway and targeted for lysosomal degradation, representing a defense against bacterial exploitation of the host cytosol. Autophagic capture of Salmonella Typhimurium occurs predominantly via generation of a polyubiquitin signal around cytosolic bacteria, binding of adaptor proteins, and recruitment of autophagic machinery. However, the components mediating bacterial target selection and ubiquitination remain obscure. We identify LRSAM1 as the E3 ligase responsible for anti-Salmonella autophagy-associated ubiquitination. LRSAM1 localizes to several intracellular bacterial pathogens and generates the bacteria-associated ubiquitin signal; these functions require LRSAM1’s leucine-rich repeat and RING domains, respectively. Using cells from LRSAM1-deficient individuals, we confirm that LRSAM1 is required for ubiquitination associated with intracellular bacteria but dispensable for ubiquitination of aggregated proteins. LRSAM1 is therefore a bacterial recognition protein and ubiquitin ligase that defends the cytoplasm from invasive pathogens. PMID:23245322

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

    PubMed Central

    Frohlich, Kyla M.

    2013-01-01

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

  4. 8/2/10 8:48 AMThe Moral Obligations of Scientists -Commentary -The Chronicle of Higher Education Page 1 of 4http://forums.chronicle.com/article/The-Moral-Obligations-of/123725/

    E-print Network

    8/2/10 8:48 AMThe Moral Obligations of Scientists - Commentary - The Chronicle of Higher Education Page 1 of 4http://forums.chronicle.com/article/The-Moral-Obligations-of/123725/ Home Opinion & Ideas Commentary Commentary August 1, 2010 The Moral Obligations of Scientists By John A. Vucetich and Michael P

  5. [Bacterial overgrowth syndrome].

    PubMed

    Stein, J M; Schneider, A R

    2007-07-01

    Small bowel bacterial overgrowth is a syndrome caused by an abnormal number of bacteria in the upper part of the small bowel and associated with a complex array of clinical symptoms, i. e., chronic diarrhoea, steatorrhoea, macrocytic anaemia, weight loss, and less commonly, protein-losing enteropathy. The most common underlying factors are small intestinal stagnation or dysmotility, intestinal obstruction, blind or afferent loops, and decreased gastric secretion. The treatment usually consists in the eradication of bacterial overgrowth with repeated courses of antimicrobials, correction of associated nutritional deficiencies and, when possible, correction of the underlying predisposing conditions. PMID:17620228

  6. [Bacterial vaginosis and pregnancy].

    PubMed

    Canova, I; Caputo, S; Ciardo, A; Stragapede, B

    2002-01-01

    Premature rupture of membranes (PROM) occurs in approximately 5-10% of all pregnancies and is implicated in approximately one third of preterm births. PROM is associated with increased risks of perinatal as well as maternal morbidity and mortality at every gestational age. Much information suggest that the presence of bacterial vaginosis may be implicated in the occurrence of PROM and subsequent preterm delivery in significant numbers of pregnant women. We will briefly review clinical and pathophysiologic information linking bacterial vaginosis and PROM. PMID:12510420

  7. Dale C, Dunbar H, Moran NA, Ochman H. 2005. Extracting single genomes from heterogenous DNAsamples:Atest case with Carsonella ruddii, the bacterial symbiont of psyllids (Insecta). 6pp. Journal of Insect Science, 5:3,

    E-print Network

    Ochman, Howard

    .org Extracting single genomes from heterogenous DNA samples: A test case with Carsonella ruddii, the bacterialDale C, Dunbar H, Moran NA, Ochman H. 2005. Extracting single genomes from heterogenous DNAsamples to the study of many bacterial symbionts that live intracellularly in insects and other animals. To recover

  8. Intracellular bacterial communities of uropathogenic Escherichia coli in urinary tract pathogenesis

    Microsoft Academic Search

    Gregory G. Anderson; Karen W. Dodson; Thomas M. Hooton; Scott J. Hultgren

    2004-01-01

    Urinary tract infections in young, healthy women frequently recur, despite their traditional classification as acute infections. Conventional wisdom dictates that uropathogens causing recurrent infections in such individuals come from the fecal or vaginal flora, in the same manner as the initial infection. However, recent studies of uropathogenic Escherichia coli have found that it can carry out a complex developmental program

  9. CpG-induced immunomodulation and intracellular bacterial killing in a chicken macrophage cell line

    Microsoft Academic Search

    Hang Xie; Richard B Raybourne; Uma S Babu; Hyun S Lillehoj; Robert A Heckert

    2003-01-01

    The immunostimulatory properties of synthetic CpG oligodeoxynucleotides (ODNs) have been studied in various mammalian models including humans and mice. However, little was known about effects of CpG ODNs on immune responses of chickens, a common avian species with important economical value in the poultry industry. In the present study, two CpG ODNs, 2006 and 1826, which show immunomodulating properties for

  10. Effect of Intracellular pH on Rotational Speed of Bacterial Flagellar Motors

    Microsoft Academic Search

    Tohru Minamino; Yasuo Imae; Fumio Oosawa; Yuji Kobayashi; Kenji Oosawa

    2003-01-01

    Weak acids such as acetate and benzoate, which partially collapse the transmembrane proton gradient, not only mediate pH taxis but also impair the motility of Escherichia coli and Salmonella at an external pH of 5.5. In this study, we examined in more detail the effect of weak acids on motility at various external pH values. A change of external pH

  11. Dual effect of interferon (IFN?)-induced nitric oxide on tumorigenesis and intracellular bacteria.

    PubMed

    Zea, Arnold H; Aiyar, Ashok; Tate, David

    2014-01-01

    Nitric oxide (NO) is a key messenger involved in numerous physiological functions including inflammatory and immune responses. The functions of NO and their underlying mechanisms have been elucidated by extensive studies over the past 10 years. However, the complexity of the interactions between different levels of NO and multiple aspects of tumor development/progression as well as bacterial pathogenesis has led to apparently conflicting findings. The precise role of NO in bacterial and tumor pathogenesis involves a multitude of inter- and intracellular signaling pathways in which interferon gamma signaling and L-arginine metabolism are the major pathways involved in NO synthesis and regulation. The availability of the amino acid L-Arg can be a key factor to control the expression of inducible nitric oxide synthase (NOS2) and cellular NO levels. The role played by the NOS2/NO system both in bacterial pathogenesis and in tumor development is complex due to the dual role these molecules can play promoting or inhibiting infections and cancer. This duality brings to the table a double challenge to determine the net impact of NO on cancer or bacterial behavior and to define the therapeutic role of NO-centered anticancer or antibacterial strategies. We believe that a comprehensive and dynamic understanding of the cascade of molecular and cellular events underlying tumor biology and bacterial pathogenesis that are affected by NO will allow researchers to exploit the potential antitumor and antibacterial properties of drugs interfering with NO metabolism. The contrasting roles of NO/NOS2 in these processes are clarified in this chapter. PMID:25189392

  12. 31 CFR 538.508 - Certain payments by the Government of Sudan of obligations to persons within the United States...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Certain payments by the Government of Sudan of obligations to persons within the United... Certain payments by the Government of Sudan of obligations to persons within the United...payment of obligations of the Government of Sudan to persons or accounts within the...

  13. Nanomedicine as an emerging approach against intracellular pathogens

    PubMed Central

    Armstead, Andrea L; Li, Bingyun

    2011-01-01

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

  14. Bacterial influence on the production of paralytic shellfish toxins by dinoflagellated algae.

    PubMed

    Dantzer, W R; Levin, R E

    1997-10-01

    This study investigated the role of intracellular and extracellular bacteria in the production of paralytic shellfish toxins by dinoflagellated algal cells. Three strains of the toxic dinoflagellate species, Alexandrium tamarense, were purified by external bacteria using penicillin G (Pen. G) at levels of 500 and 1000 p.p.m. Levels of toxicity of the resulting purified dinoflagellate cultures were similar to those of the original strains contaminated with external bacteria, indicating that the external bacteria had no influence on toxicity. No bacterial colony forming units (cfu) arose from disruption of algal cells derived from penicillin-treated cultures, indicating that intracellular bacteria were not responsible for the toxicity of cultures. PMID:9351228

  15. Atypical Response Regulator ChxR from Chlamydia trachomatis Is Structurally Poised for DNA Binding

    E-print Network

    Barta, Michael L.; Hickey, John Michael; Anbanandam, Asokan; Dyer, Kevin; Hammel, Michal; Hefty, P. Scott

    2014-03-19

    ChxR is an atypical two-component signal transduction response regulator (RR) of the OmpR/PhoB subfamily encoded by the obligate intracellular bacterial pathogen Chlamydia trachomatis. Despite structural homology within ...

  16. Immunopotentiation for bacterial biodefense.

    PubMed

    Skyberg, Jerod A

    2014-01-01

    Activation of the innate immune system can enhance resistance to a variety of bacterial and viral infections. In situations where the etiological agent of disease is unknown, such as a bioterror attack, stimulation of innate immunity may be particularly useful as induced immune responses are often capable of providing protection against a broad range of pathogens. In particular, the threat of an intentional release of a highly virulent bacterial pathogen that is either intrinsically resistant to antibiotics, or has been weaponized via the introduction of antibiotic resistance, makes immunopotentiation an attractive complementary or alternative strategy to enhance resistance to bacterial biothreat agents. Francisella tularensis, Yersinia pestis, Bacillus anthracis, and Burkholderia mallei or pseudomallei can all be easily disseminated via the respiratory route and infections can result in high mortality rates. Therefore, there has been a marked increase in research on immunotherapeutics against these Tier 1 select agents over the last 10 years that will be covered in this review. In addition, immunopotentiation against non-Tier 1 select agents such as Brucella spp., and Coxiella burnetii has also been studied and will be reviewed here. In particular, we will focus on cellular targets, such as toll-like receptors (TLRs), carbohydrate receptors and cytokine receptors, which have been exploited by immunomodulatory regimens that confer broad-spectrum protection against virulent bacterial pathogens. PMID:25373479

  17. Bacterial leaf spot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial leaf spot has been reported in Australia (Queensland), Egypt, El Salvador, India, Japan, Nicaragua, Sudan, and the United States (Florida, Iowa, Kansas, Maryland, and Wisconsin). It occasionally causes locally severe defoliation and post-emergence damping-off and stunting. The disease is...

  18. Bacterial social engagements

    Microsoft Academic Search

    Jennifer M. Henke; Bonnie L. Bassler

    2004-01-01

    Quorum sensing is a process that enables bacteria to communicate using secreted signaling molecules called autoinducers. This process enables a population of bac- teria to regulate gene expression collectively and, there- fore, control behavior on a community-wide scale. Quorum sensing is widespread in the bacterial world and, generally, processes controlled by quorum sensing are unproductive when undertaken by an individual

  19. Bacterial microflora of nectarines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microflora of fruit surfaces has been the best source of antagonists against fungi causing postharvest decays of fruit. However, there is little information on microflora colonizing surfaces of fruits other than grapes, apples, and citrus fruit. We characterized bacterial microflora on nectarine f...

  20. Extracellular and intracellular anti-mutagenic effects of bile pigments in the Salmonella typhimurium reverse mutation assay

    PubMed Central

    Mölzer, C.; Huber, H.; Diem, K.; Wallner, M.; Bulmer, A.C.; Wagner, K.-H.

    2013-01-01

    In vitro anti-genotoxic properties of bile pigments have been explored and confirmed recently. Despite these reports mechanisms to explain DNA protection by endogenous bile pigments remain unclear. Surprisingly, the quantification of cellular pigment absorption which could represent a fundamental prerequisite for intracellular (e.g., anti-mutagenic) effects, has not been explored. Therefore, we aimed to measure the amounts of un-/conjugated bilirubin as well as biliverdin absorbed into colonies of Salmonella typhimurium, utilising HPLC analyses, and to observe whether intracellular compound concentrations could predict anti-genotoxic effects. HPLC analyses confirmed that bacterial bile pigment absorption was concentration-dependent. Plate bile pigment concentrations were inversely associated with genotoxicity of all tested mutagens, irrespective of strain and test conditions. However, protection against frame-shift mutation in strain TA98 most strongly depended on the bacterial absorption of bilirubin and biliverdin, which indicates that bile pigments can protect by intercepting mutations extracellularly and specifically inhibit frame-shift mutations intracellularly. PMID:22906569