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Sample records for obligate intracellular pathogens

  1. Advances in genetic manipulation of obligate intracellular bacterial pathogens

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    Paul eBeare

    2011-05-01

    Full Text Available 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 α-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.

  2. An optimal method of iron starvation of the obligate intracellular pathogen, Chlamydia trachomatis

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    Christopher C. Thompson

    2011-02-01

    Full Text Available 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 in a single-treatment time-of-infection regimen. 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.

  3. Antibody-mediated immunity to the obligate intracellular bacterial pathogen Coxiella burnetii is Fc receptor- and complement-independent

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    Heinzen Robert A

    2009-05-01

    Full Text Available Abstract Background The obligate intracellular bacterial pathogen Coxiella burnetii causes the zoonosis Q fever. The intracellular niche of C. burnetii has led to the assumption that cell-mediated immunity is the most important immune component for protection against this pathogen. However, passive immunization with immune serum can protect naïve animals from challenge with virulent C. burnetii, indicating a role for antibody (Ab in protection. The mechanism of this Ab-mediated protection is unknown. Therefore, we conducted a study to determine whether Fc receptors (FcR or complement contribute to Ab-mediated immunity (AMI to C. burnetii. Results Virulent C. burnetii infects and replicates within human dendritic cells (DC without inducing their maturation or activation. We investigated the effects of Ab opsonized C. burnetii on human monocyte-derived and murine bone marrow-derived DC. Infection of DC with Ab-opsonized C. burnetii resulted in increased expression of maturation markers and inflammatory cytokine production. Bacteria that had been incubated with naïve serum had minimal effect on DC, similar to virulent C. burnetii alone. The effect of Ab opsonized C. burnetii on DC was FcR dependent as evidenced by a reduced response of DC from FcR knockout (FcR k/o compared to C57Bl/6 (B6 mice. To address the potential role of FcR in Ab-mediated protection in vivo, we compared the response of passively immunized FcR k/o mice to the B6 controls. Interestingly, we found that FcR are not essential for AMI to C. burnetii in vivo. We subsequently examined the role of complement in AMI by passively immunizing and challenging several different strains of complement-deficient mice and found that AMI to C. burnetii is also complement-independent. Conclusion Despite our data showing FcR-dependent stimulation of DC in vitro, Ab-mediated immunity to C. burnetii in vivo is FcR-independent. We also found that passive immunity to this pathogen is independent of

  4. Secretome of obligate intracellular Rickettsia

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

    2014-01-01

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

  5. Manipulation of Host Cholesterol by Obligate Intracellular Bacteria

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    Dhritiman Samanta

    2017-05-01

    Full Text Available Cholesterol is a multifunctional lipid that plays important metabolic and structural roles in the eukaryotic cell. Despite having diverse lifestyles, the obligate intracellular bacterial pathogens Chlamydia, Coxiella, Anaplasma, Ehrlichia, and Rickettsia all target cholesterol during host cell colonization as a potential source of membrane, as well as a means to manipulate host cell signaling and trafficking. To promote host cell entry, these pathogens utilize cholesterol-rich microdomains known as lipid rafts, which serve as organizational and functional platforms for host signaling pathways involved in phagocytosis. Once a pathogen gains entrance to the intracellular space, it can manipulate host cholesterol trafficking pathways to access nutrient-rich vesicles or acquire membrane components for the bacteria or bacteria-containing vacuole. To acquire cholesterol, these pathogens specifically target host cholesterol metabolism, uptake, efflux, and storage. In this review, we examine the strategies obligate intracellular bacterial pathogens employ to manipulate cholesterol during host cell colonization. Understanding how obligate intracellular pathogens target and use host cholesterol provides critical insight into the host-pathogen relationship.

  6. Engineering of obligate intracellular bacteria: progress, challenges and paradigms

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    Over twenty years have passed since the first report of genetic manipulation of an obligate intracellular bacterium. Through progress interspersed by bouts of stagnation, microbiologists and geneticists have developed approaches to genetically manipulate obligates. A brief overview of the current ge...

  7. Economic Game Theory to Model the Attenuation of Virulence of an Obligate Intracellular Bacterium.

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    Tago, Damian; Meyer, Damien F

    2016-01-01

    Diseases induced by obligate intracellular pathogens have a large burden on global human and animal health. Understanding the factors involved in the virulence and fitness of these pathogens contributes to the development of control strategies against these diseases. Based on biological observations, a theoretical model using game theory is proposed to explain how obligate intracellular bacteria interact with their host. The equilibrium in such a game shows that the virulence and fitness of the bacterium is host-triggered and by changing the host's defense system to which the bacterium is confronted, an evolutionary process leads to an attenuated strain. Although, the attenuation procedure has already been conducted in practice in order to develop an attenuated vaccine (e.g., with Ehrlichia ruminantium), there was a lack of understanding of the theoretical basis behind this process. Our work provides a model to better comprehend the existence of different phenotypes and some underlying evolutionary mechanisms for the virulence of obligate intracellular bacteria.

  8. Pathogenic mechanisms of intracellular bacteria.

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    Niller, Hans Helmut; Masa, Roland; Venkei, Annamária; Mészáros, Sándor; Minarovits, Janos

    2017-06-01

    We wished to overview recent data on a subset of epigenetic changes elicited by intracellular bacteria in human cells. Reprogramming the gene expression pattern of various host cells may facilitate bacterial growth, survival, and spread. DNA-(cytosine C5)-methyltransferases of Mycoplasma hyorhinis targeting cytosine-phosphate-guanine (CpG) dinucleotides and a Mycobacterium tuberculosis methyltransferase targeting non-CpG sites methylated the host cell DNA and altered the pattern of gene expression. Gene silencing by CpG methylation and histone deacetylation, mediated by cellular enzymes, also occurred in M. tuberculosis-infected macrophages. M. tuberculosis elicited cell type-specific epigenetic changes: it caused increased DNA methylation in macrophages, but induced demethylation, deposition of euchromatic histone marks and activation of immune-related genes in dendritic cells. A secreted transposase of Acinetobacter baumannii silenced a cellular gene, whereas Mycobacterium leprae altered the epigenotype, phenotype, and fate of infected Schwann cells. The 'keystone pathogen' oral bacterium Porphyromonas gingivalis induced local DNA methylation and increased the level of histone acetylation in host cells. These epigenetic changes at the biofilm-gingiva interface may contribute to the development of periodontitis. Epigenetic regulators produced by intracellular bacteria alter the epigenotype and gene expression pattern of host cells and play an important role in pathogenesis.

  9. Rickettsia phylogenomics: unwinding the intricacies of obligate intracellular life.

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    Joseph J Gillespie

    Full Text Available BACKGROUND: Completed genome sequences are rapidly increasing for Rickettsia, obligate intracellular alpha-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 (approximately 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

  10. Analysis of convergent gene transcripts in the obligate intracellular bacterium Rickettsia prowazekii.

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    Andrew Woodard

    2011-01-01

    Full Text Available Termination of transcription is an important component of bacterial gene expression. However, little is known concerning this process in the obligate intracellular pathogen and model for reductive evolution, Rickettsia prowazekii. To assess transcriptional termination in this bacterium, transcripts of convergent gene pairs, some containing predicted intrinsic terminators, were analyzed. These analyses revealed that, rather than terminating at a specific site within the intervening region between the convergent genes, most of the transcripts demonstrated either a lack of termination within this region, which generated antisense RNA, or a putative non-site-specific termination that occurred throughout the intervening sequence. Transcripts terminating at predicted intrinsic terminators, as well as at a putative Rho-dependant terminator, were also examined and found to vary based on the rickettsial host environment. These results suggest that transcriptional termination, or lack thereof, plays a role in rickettsial gene regulation.

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

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

    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.

  12. The Chlamydia psittaci genome: a comparative analysis of intracellular pathogens.

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    Voigt, Anja; Schöfl, Gerhard; Saluz, Hans Peter

    2012-01-01

    Chlamydiaceae are a family of obligate intracellular pathogens causing a wide range of diseases in animals and humans, and facing unique evolutionary constraints not encountered by free-living prokaryotes. To investigate genomic aspects of infection, virulence and host preference we have sequenced Chlamydia psittaci, the pathogenic agent of ornithosis. A comparison of the genome of the avian Chlamydia psittaci isolate 6BC with the genomes of other chlamydial species, C. trachomatis, C. muridarum, C. pneumoniae, C. abortus, C. felis and C. caviae, revealed a high level of sequence conservation and synteny across taxa, with the major exception of the human pathogen C. trachomatis. Important differences manifest in the polymorphic membrane protein family specific for the Chlamydiae and in the highly variable chlamydial plasticity zone. We identified a number of psittaci-specific polymorphic membrane proteins of the G family that may be related to differences in host-range and/or virulence as compared to closely related Chlamydiaceae. We calculated non-synonymous to synonymous substitution rate ratios for pairs of orthologous genes to identify putative targets of adaptive evolution and predicted type III secreted effector proteins. This study is the first detailed analysis of the Chlamydia psittaci genome sequence. It provides insights in the genome architecture of C. psittaci and proposes a number of novel candidate genes mostly of yet unknown function that may be important for pathogen-host interactions.

  13. The Chlamydia psittaci genome: a comparative analysis of intracellular pathogens.

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    Anja Voigt

    Full Text Available Chlamydiaceae are a family of obligate intracellular pathogens causing a wide range of diseases in animals and humans, and facing unique evolutionary constraints not encountered by free-living prokaryotes. To investigate genomic aspects of infection, virulence and host preference we have sequenced Chlamydia psittaci, the pathogenic agent of ornithosis.A comparison of the genome of the avian Chlamydia psittaci isolate 6BC with the genomes of other chlamydial species, C. trachomatis, C. muridarum, C. pneumoniae, C. abortus, C. felis and C. caviae, revealed a high level of sequence conservation and synteny across taxa, with the major exception of the human pathogen C. trachomatis. Important differences manifest in the polymorphic membrane protein family specific for the Chlamydiae and in the highly variable chlamydial plasticity zone. We identified a number of psittaci-specific polymorphic membrane proteins of the G family that may be related to differences in host-range and/or virulence as compared to closely related Chlamydiaceae. We calculated non-synonymous to synonymous substitution rate ratios for pairs of orthologous genes to identify putative targets of adaptive evolution and predicted type III secreted effector proteins.This study is the first detailed analysis of the Chlamydia psittaci genome sequence. It provides insights in the genome architecture of C. psittaci and proposes a number of novel candidate genes mostly of yet unknown function that may be important for pathogen-host interactions.

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

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

    2005-09-01

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

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

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    Pareja, Maria Eugenia Mansilla; Colombo, Maria I

    2013-01-01

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

  16. Targeting solid tumors with non-pathogenic obligate anaerobic bacteria.

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    Taniguchi, Shun'ichiro; Fujimori, Minoru; Sasaki, Takayuki; Tsutsui, Hiroko; Shimatani, Yuko; Seki, Keiichi; Amano, Jun

    2010-09-01

    Molecular-targeting drugs with fewer severe adverse effects are attracting great attention as the next wave of cancer treatment. There exist, however, populations of cancer cells resistant to these drugs that stem from the instability of tumor cells and/or the existence of cancer stem cells, and thus specific toxicity is required to destroy them. If such selectivity is not available, these targets may be sought out not by the cancer cell types themselves, but rather in their adjacent cancer microenvironments by means of hypoxia, low pH, and so on. The anaerobic conditions present in malignant tumor tissues have previously been regarded as a source of resistance in cancer cells against conventional therapy. However, there now appears to be a way to make use of these limiting factors as a selective target. In this review, we will refer to several trials, including our own, to direct attention to the utilizable anaerobic conditions present in malignant tumor tissues and the use of bacteria as carriers to target them. Specifically, we have been developing a method to attack solid cancers using the non-pathogenic obligate anaerobic bacterium Bifidobacterium longum as a vehicle to selectively recognize and target the anaerobic conditions in solid cancer tissues. We will also discuss the existence of low oxygen pressure in tumor masses in spite of generally enhanced angiogenesis, overview current cancer therapies, especially the history and present situation of bacterial utility to treat solid tumors, and discuss the rationality and future possibilities of this novel mode of cancer treatment. © 2010 Japanese Cancer Association.

  17. Non-coding RNA regulation in pathogenic bacteria located inside eukaryotic cells

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    Ortega, Alvaro D.; Quereda, Juan J; Pucciarelli, M Graciela; García-del Portillo, Francisco

    2014-01-01

    Intracellular bacterial pathogens have evolved distinct lifestyles inside eukaryotic cells. Some pathogens coexist with the infected cell in an obligate intracellular state, whereas others transit between the extracellular and intracellular environment. Adaptation to these intracellular lifestyles

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

    KAUST Repository

    Woo, Yong

    2015-07-15

    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. © Woo et al.

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

    KAUST Repository

    Woo, Yong; Ansari, Hifzur Rahman; Otto, Thomas D.; Linger, Christen M K; Olisko, Martin K.; Michá lek, Jan; Saxena, Alka; Shanmugam, Dhanasekaran; Tayyrov, Annageldi; Veluchamy, Alaguraj; Ali, Shahjahan; Bernal, Axel; Del Campo, Javier; Cihlá ř, Jaromí r; Flegontov, Pavel; Gornik, Sebastian G.; Hajdušková , Eva; Horá k, Aleš; Janouškovec, Jan; Katris, Nicholas J.; Mast, Fred D.; Miranda-Saavedra, Diego; Mourier, Tobias; Naeem, Raeece; Nair, Mridul; Panigrahi, Aswini Kumar; Rawlings, Neil D.; Padron Regalado, Eriko; Ramaprasad, Abhinay; Samad, Nadira; Tomčala, 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; Oborní k, 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. © Woo et al.

  20. Characteristic features of intracellular pathogenic Leptospira in infected murine macrophages.

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    Toma, Claudia; Okura, Nobuhiko; Takayama, Chitoshi; Suzuki, Toshihiko

    2011-11-01

    Leptospira interrogans is a spirochaete responsible for a zoonotic disease known as leptospirosis. Leptospires are able to penetrate the abraded skin and mucous membranes and rapidly disseminate to target organs such as the liver, lungs and kidneys. How this pathogen escape from innate immune cells and spread to target organs remains poorly understood. In this paper, the intracellular trafficking undertaken by non-pathogenic Leptospira biflexa and pathogenic L. interrogans in mouse bone marrow-derived macrophages was compared. The delayed in the clearance of L. interrogans was observed. Furthermore, the acquisition of lysosomal markers by L. interrogans-containing phagosomes lagged behind that of L. biflexa-containing phagosomes, and although bone marrow-derived macrophages could degrade L. biflexa as well as L. interrogans, a population of L. interrogans was able to survive and replicate. Intact leptospires were found within vacuoles at 24 h post infection, suggesting that bacterial replication occurs within a membrane-bound compartment. In contrast, L. biflexa were completely degraded at 24 h post infection. Furthermore, L. interrogans but not L. biflexa, were released to the extracellular milieu. These results suggest that pathogenic leptospires are able to survive, replicate and exit from mouse macrophages, enabling their eventual spread to target organs. © 2011 Blackwell Publishing Ltd.

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

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

    2008-02-28

    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) scheme to understand the population genetic structure and diversity of these species and to evaluate the association between genotype and disease. A collection of 26 strains of C. trachomatis of different serovars and clinical presentation and 18 strains of C. pneumoniae were included in the study. For comparison, sequences of C. abortus, C. psittaci, C. caviae, C. felis, C. pecorum (Chlamydophila), C. muridarum (Chlamydia) and of Candidatus protochlamydia and Simkania negevensis were also included. Sequences of fragments (400 - 500 base pairs) from seven housekeeping genes (enoA, fumC, gatA, gidA, hemN, hlfX, oppA) were analysed. Analysis of allelic profiles by eBurst revealed three non-overlapping clonal complexes among the C. trachomatis strains, while the C. pneumoniae strains formed a single group. An UPGMA tree produced from the allelic profiles resulted in three groups of sequence types. The LGV strains grouped in a single cluster, while the urogenital strains were distributed over two separated groups, one consisted solely of strains with frequent occurring serovars (E, D and F). The distribution of the different serovars over the three groups was not consistent, suggesting exchange of serovar encoding ompA sequences. In one instance, exchange of fumC sequences between strains of different groups was observed. Cluster analyses of concatenated sequences of the Chlamydophila and Chlamydia species together with those of Candidatus Protochlamydia amoebophila and Simkania negevensis resulted in a tree identical to that

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

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    Langerak Ankie A

    2008-02-01

    Full Text Available Abstract 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 scheme to understand the population genetic structure and diversity of these species and to evaluate the association between genotype and disease. Results A collection of 26 strains of C. trachomatis of different serovars and clinical presentation and 18 strains of C. pneumoniae were included in the study. For comparison, sequences of C. abortus, C. psittaci, C. caviae, C. felis, C. pecorum (Chlamydophila, C. muridarum (Chlamydia and of Candidatus protochlamydia and Simkania negevensis were also included. Sequences of fragments (400 – 500 base pairs from seven housekeeping genes (enoA, fumC, gatA, gidA, hemN, hlfX, oppA were analysed. Analysis of allelic profiles by eBurst revealed three non-overlapping clonal complexes among the C. trachomatis strains, while the C. pneumoniae strains formed a single group. An UPGMA tree produced from the allelic profiles resulted in three groups of sequence types. The LGV strains grouped in a single cluster, while the urogenital strains were distributed over two separated groups, one consisted solely of strains with frequent occurring serovars (E, D and F. The distribution of the different serovars over the three groups was not consistent, suggesting exchange of serovar encoding ompA sequences. In one instance, exchange of fumC sequences between strains of different groups was observed. Cluster analyses of concatenated sequences of the Chlamydophila and Chlamydia species together with those of Candidatus Protochlamydia amoebophila and Simkania

  3. The genome of the obligate intracellular parasite Trachipleistophora hominis: new insights into microsporidian genome dynamics and reductive evolution.

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    Eva Heinz

    Full Text Available 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

  4. Modeling the intracellular pathogen-immune interaction with cure rate

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    Dubey, Balram; Dubey, Preeti; Dubey, Uma S.

    2016-09-01

    Many common and emergent infectious diseases like Influenza, SARS, Hepatitis, Ebola etc. are caused by viral pathogens. These infections can be controlled or prevented by understanding the dynamics of pathogen-immune interaction in vivo. In this paper, interaction of pathogens with uninfected and infected cells in presence or absence of immune response are considered in four different cases. In the first case, the model considers the saturated nonlinear infection rate and linear cure rate without absorption of pathogens into uninfected cells and without immune response. The next model considers the effect of absorption of pathogens into uninfected cells while all other terms are same as in the first case. The third model incorporates innate immune response, humoral immune response and Cytotoxic T lymphocytes (CTL) mediated immune response with cure rate and without absorption of pathogens into uninfected cells. The last model is an extension of the third model in which the effect of absorption of pathogens into uninfected cells has been considered. Positivity and boundedness of solutions are established to ensure the well-posedness of the problem. It has been found that all the four models have two equilibria, namely, pathogen-free equilibrium point and pathogen-present equilibrium point. In each case, stability analysis of each equilibrium point is investigated. Pathogen-free equilibrium is globally asymptotically stable when basic reproduction number is less or equal to unity. This implies that control or prevention of infection is independent of initial concentration of uninfected cells, infected cells, pathogens and immune responses in the body. The proposed models show that introduction of immune response and cure rate strongly affects the stability behavior of the system. Further, on computing basic reproduction number, it has been found to be minimum for the fourth model vis-a-vis other models. The analytical findings of each model have been exemplified by

  5. Transcriptomic insight into pathogenicity-associated factors of Conidiobolus obscurus, an obligate aphid-pathogenic fungus belonging to Entomopthoromycota.

    Science.gov (United States)

    Wang, Jianghong; Zhou, Xiang; Guo, Kai; Zhang, Xinqi; Lin, Haiping; Montalva, Cristian

    2018-01-16

    Conidiobolus obscurus is a widespread fungal entomopathogen with aphid biocontrol potential. This study focused on a de novo transcriptomic analysis of C. obscurus. A number of pathogenicity-associated factors were annotated for the first time from the assembled 17 231 fungal unigenes, including those encoding subtilisin-like proteolytic enzymes (Pr1s), trypsin-like proteases, metalloproteases, carboxypeptidases and endochitinases. Many of these genes were transcriptionally up-regulated by at least twofold in mycotized cadavers compared with the in vitro fungal cultures. The resultant transcriptomic database was validated by the transcript levels of three selected pathogenicity-related genes quantified from different in vivo and in vitro material in real-time quantitative polymerase chain reaction (PCR). The involvement of multiple Pr1 proteases in the first stage of fungal infection was also suggested. Interestingly, a unique cytolytic (Cyt)-like δ-endotoxin gene was highly expressed in both mycotized cadavers and fungal cultures, and was more or less distinct from its homologues in bacteria and other fungi. Our findings provide the first global insight into various pathogenicity-related genes in this obligate aphid pathogen and may help to develop novel biocontrol strategy against aphid pests. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

  6. Intracellular phase for an extracellular bacterial pathogen: MgtC shows the way

    Directory of Open Access Journals (Sweden)

    Audrey Bernut

    2015-08-01

    Full Text Available Pseudomonas aeruginosa is an extracellular pathogen known to impair host phagocytic functions. However, our recent results identify MgtC as a novel actor in P. aeruginosa virulence, which plays a role in an intramacrophage phase of this pathogen. In agreement with its intracellular function, P. aeruginosa mgtC gene expression is strongly induced when the bacteria reside within macrophages. MgtC was previously known as a horizontally-acquired virulence factor important for multiplication inside macrophages in several intracellular bacterial pathogens. MgtC thus provides a singular example of a virulence determinant that subverts macrophages both in intracellular and extracellular pathogens. Moreover, we demonstrate that P. aeru-ginosa MgtC is required for optimal growth in Mg2+ deprived medium, a property shared by MgtC factors from intracellular pathogens and, under Mg2+ limitation, P. aeruginosaMgtC prevents biofilm formation. We propose that MgtC has a similar function in intracellular and extracellular pathogens, which contributes to macrophage resistance and fine-tune adaptation to the host in relation to the different bacterial lifestyles. MgtC thus appears as an attractive target for antivirulence strategies and our work provides a natural peptide as MgtC antagonist, which paves the way for the development of MgtC inhibitors.

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

    Science.gov (United States)

    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

  8. Cytosolic Access of Intracellular Bacterial Pathogens: The Shigella Paradigm.

    Science.gov (United States)

    Mellouk, Nora; Enninga, Jost

    2016-01-01

    Shigella is a Gram-negative bacterial pathogen, which causes bacillary dysentery in humans. A crucial step of Shigella infection is its invasion of epithelial cells. Using a type III secretion system, Shigella injects several bacterial effectors ultimately leading to bacterial internalization within a vacuole. Then, Shigella escapes rapidly from the vacuole, it replicates within the cytosol and spreads from cell-to-cell. The molecular mechanism of vacuolar rupture used by Shigella has been studied in some detail during the recent years and new paradigms are emerging about the underlying molecular events. For decades, bacterial effector proteins were portrayed as main actors inducing vacuolar rupture. This includes the effector/translocators IpaB and IpaC. More recently, this has been challenged and an implication of the host cell in the process of vacuolar rupture has been put forward. This includes the bacterial subversion of host trafficking regulators, such as the Rab GTPase Rab11. The involvement of the host in determining bacterial vacuolar integrity has also been found for other bacterial pathogens, particularly for Salmonella. Here, we will discuss our current view of host factor and pathogen effector implications during Shigella vacuolar rupture and the steps leading to it.

  9. Cytosolic access of intracellular bacterial pathogens: the Shigella paradigm

    Directory of Open Access Journals (Sweden)

    Nora eMellouk

    2016-04-01

    Full Text Available Shigella is a Gram-negative bacterial pathogen, which causes bacillary dysentery in humans. A crucial step of Shigella infection is its invasion of epithelial cells. Using a type III secretion system, Shigella injects several bacterial effectors ultimately leading to bacterial internalization within a vacuole. Then, Shigella escapes rapidly from the vacuole, it replicates within the cytosol and spreads from cell-to-cell. The molecular mechanism of vacuolar rupture used by Shigella has been studied in some detail during the recent years and new paradigms are emerging about the underlying molecular events. For decades, bacterial effector proteins were portrayed as main actors inducing vacuolar rupture. This includes the effector/translocators IpaB and IpaC. More recently, this has been challenged and an implication of the host cell in the process of vacuolar rupture has been put forward. This includes the bacterial subversion of host trafficking regulators, such as the Rab GTPase Rab11. The involvement of the host in determining bacterial vacuolar integrity has also been found for other bacterial pathogens, particularly for Salmonella. Here, we will discuss our current view of host factor and pathogen effector implications during Shigella vacuolar rupture and the steps leading to it.

  10. Post-translational Control of Intracellular Pathogen Sensing Pathways.

    Science.gov (United States)

    Chiang, Cindy; Gack, Michaela U

    2017-01-01

    Mammalian cells recognize virus-derived nucleic acids using a defined set of intracellular sensors including the DNA sensors cyclic GMP-AMP (cGAMP) synthase (cGAS) and interferon gamma (IFNγ)-inducible protein 16 (IFI16) as well as viral RNA receptors of the retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) family. Following innate immune recognition, these sensors launch an immune response that is characterized by the transcriptional upregulation of many antiviral molecules, including proinflammatory cytokines, chemokines, and IFN-stimulated genes. Recent studies have demonstrated that the signal transduction initiated by these sensors is sophisticatedly regulated by post-translational modifications (PTMs) resulting in a robust yet 'tunable' cytokine response to maintain immune homeostasis. Here we summarize recent advances in our understanding of how PTMs and regulatory enzymes control the signaling activity of RLRs, cGAS, and IFI16 as well as their proximal adaptor proteins. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Type IV pili in Francisella – A virulence trait in an intracellular pathogen

    Directory of Open Access Journals (Sweden)

    Emelie eNäslund Salomonsson

    2011-02-01

    Full Text Available Francisella tularensis is a highly virulent intracellular human pathogen that is capable of rapid proliferation in the infected host. Mutants affected in intracellular survival and growth are highly attenuated which highlights the importance of the intracellular phase of the infection. Genomic analysis has revealed that Francisella encodes all genes required for expression of functional type IV pili (Tfp, and in this focused review we summarise recent findings regarding this system in the pathogenesis of tularemia. Tfp are dynamic adhesive structures that have been identified as major virulence determinants in several human pathogens, but it is not obvious what role these structures could have in an intracellular pathogen like Francisella. In the human pathogenic strains, genes required for secretion and assembly of Tfp and one pilin, PilA, have shown to be required for full virulence. Importantly, specific genetic differences have been identified between the different Francisella subspecies where in the most pathogenic type A variants all genes are intact while several Tfp genes are pseudogenes in the less pathogenic type B strains. This suggests that there has been a selection for expression of Tfp with different properties in the different subspecies. There is also a possibility that the genetic differences reflect adaption to different environmental niches of the subspecies and plays a role in transmission of tularemia. This is also in line with recent findings where Tfp pilins are found to be glycosylated which could reflect a role for Tfp in the environment to promote survival and transmission. We are still far from understanding the role of Tfp in virulence and transmission of tularemia, but with the genomic information and genetic tools available we are in a good position to address these issues in the future.

  12. Highly abundant and stage-specific mRNAs in the obligate pathogen Bremia lactucae.

    Science.gov (United States)

    Judelson, H S; Michelmore, R W

    1990-01-01

    Germinating spores of the obligate pathogen Bremia lactucae (lettuce downy mildew) contain several unusually abundant species of mRNA. Thirty-nine cDNA clones corresponding to prevalent transcripts were isolated from a library synthesized using poly(A)+ RNA from germinating spores; these clones represented only five distinct classes. Each corresponding mRNA accounted for from 0.4 to 9 percent by mass of poly(A)+ RNA from germinating spores and together represented greater than 20 percent of the mRNA. The expression of the corresponding genes, and a gene encoding Hsp70, was analyzed in spores during germination and during growth in planta. The Hsp70 mRNA and mRNA from one abundant cDNA clone (ham34) were expressed constitutively. Two clones (ham9 and ham12) hybridized only to mRNA from spores and germinating spores. Two clones (ham37 and ham27) showed hybridization specific to germinating spores. Quantification of the number of genes homologous to each cDNA clone indicated that four clones corresponded to one or two copies per haploid genome, and one hybridized to an approximately 11-member family of genes. A sequence of the gene corresponding to ham34 was obtained to investigate its function and to identify sequences conferring high levels of gene expression for use in constructing vectors for the transformation of B. lactucae.

  13. Seroepidemiologic Survey of Potential Pathogens in Obligate and Facultative Scavenging Avian Species in California

    Science.gov (United States)

    Straub, Mary H.; Kelly, Terra R.; Rideout, Bruce A.; Eng, Curtis; Wynne, Janna; Braun, Josephine; Johnson, Christine K.

    2015-01-01

    Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats. PMID:26606755

  14. ABMA, a small molecule that inhibits intracellular toxins and pathogens by interfering with late endosomal compartments.

    Science.gov (United States)

    Wu, Yu; Pons, Valérie; Goudet, Amélie; Panigai, Laetitia; Fischer, Annette; Herweg, Jo-Ana; Kali, Sabrina; Davey, Robert A; Laporte, Jérôme; Bouclier, Céline; Yousfi, Rahima; Aubenque, Céline; Merer, Goulven; Gobbo, Emilie; Lopez, Roman; Gillet, Cynthia; Cojean, Sandrine; Popoff, Michel R; Clayette, Pascal; Le Grand, Roger; Boulogne, Claire; Tordo, Noël; Lemichez, Emmanuel; Loiseau, Philippe M; Rudel, Thomas; Sauvaire, Didier; Cintrat, Jean-Christophe; Gillet, Daniel; Barbier, Julien

    2017-11-14

    Intracellular pathogenic microorganisms and toxins exploit host cell mechanisms to enter, exert their deleterious effects as well as hijack host nutrition for their development. A potential approach to treat multiple pathogen infections and that should not induce drug resistance is the use of small molecules that target host components. We identified the compound 1-adamantyl (5-bromo-2-methoxybenzyl) amine (ABMA) from a cell-based high throughput screening for its capacity to protect human cells and mice against ricin toxin without toxicity. This compound efficiently protects cells against various toxins and pathogens including viruses, intracellular bacteria and parasite. ABMA provokes Rab7-positive late endosomal compartment accumulation in mammalian cells without affecting other organelles (early endosomes, lysosomes, the Golgi apparatus, the endoplasmic reticulum or the nucleus). As the mechanism of action of ABMA is restricted to host-endosomal compartments, it reduces cell infection by pathogens that depend on this pathway to invade cells. ABMA may represent a novel class of broad-spectrum compounds with therapeutic potential against diverse severe infectious diseases.

  15. Epigenetic silencing of host cell defense genes enhances intracellular survival of the rickettsial pathogen Anaplasma phagocytophilum.

    Directory of Open Access Journals (Sweden)

    Jose C Garcia-Garcia

    2009-06-01

    Full Text Available Intracellular bacteria have evolved mechanisms that promote survival within hostile host environments, often resulting in functional dysregulation and disease. Using the Anaplasma phagocytophilum-infected granulocyte model, we establish a link between host chromatin modifications, defense gene transcription and intracellular bacterial infection. Infection of THP-1 cells with A. phagocytophilum led to silencing of host defense gene expression. Histone deacetylase 1 (HDAC1 expression, activity and binding to the defense gene promoters significantly increased during infection, which resulted in decreased histone H3 acetylation in infected cells. HDAC1 overexpression enhanced infection, whereas pharmacologic and siRNA HDAC1 inhibition significantly decreased bacterial load. HDAC2 does not seem to be involved, since HDAC2 silencing by siRNA had no effect on A. phagocytophilum intracellular propagation. These data indicate that HDAC up-regulation and epigenetic silencing of host cell defense genes is required for A. phagocytophilum infection. Bacterial epigenetic regulation of host cell gene transcription could be a general mechanism that enhances intracellular pathogen survival while altering cell function and promoting disease.

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

    DEFF Research Database (Denmark)

    Cortes-Bratti, Ximena; Brasseres, Eugenie; Herrera-Rodriquez, Fabiola

    2011-01-01

    Background: Thioredoxin 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 Findings: In 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 which replicate in the cytosol and the endoplasmic reticulum respectively. Our data indicate that TAMs efficiently inhibit intracellular growth of both L...... in TAMs compared to that observed in control cells 24 h post-infection, indicating that TAMs kill bacteria by preventing their escape from the endosomal compartments, which progress into a highly degradative phagolysosome. Significance: Our results show that Trx80 potentiates the bactericidal activities...

  17. Biolistic transformation of the obligate plant pathogenic fungus, Erysiphe graminis f.sp. hordei

    DEFF Research Database (Denmark)

    Christiansen, S.K.; Knudsen, S.; Giese, H.

    1995-01-01

    Particle gun acceleration appears to be a possible way to transform mycelium cells of obligate plant parasites growing on host surfaces, GUS expression was obtained in E. graminis f.sp. hordei cells after bombardment with the GUS gene under the control of the E. graminis f.sp. hordei beta...

  18. Pathogenicity of facultative and obligate anaerobic bacteria in monoculture and combined with either Prevotella intermedia or Prevotella nigrescens.

    Science.gov (United States)

    Siqueira, J F; Magalhães, F A; Lima, K C; de Uzeda, M

    1998-12-01

    The pathogenicity of obligate and facultative anaerobic bacteria commonly found in endodontic infections was tested using a mouse model. The capacity of inducing abscesses was evaluated seven days after subcutaneous injection of the bacteria in pure culture and in combinations with either Prevotella intermedia or Prevotella nigrescens. Nine of the fifteen bacterial strains tested were pathogenic in pure culture. No statistically significant differences were detected between these strains in pure culture and in mixtures with either P. intermedia or P. nigrescens. Synergism between the bacterial strains was only apparent when associating Porphyromonas endodontalis with P. intermedia or P. nigrescens. Histopathological examination of tissue sections from induced abscesses revealed an acute inflammatory reaction, dominated by polymorphonuclear leukocytes. Sections from the control group using sterile medium showed no evidence of inflammatory reaction.

  19. Brucella abortus Induces a Warburg Shift in Host Metabolism That Is Linked to Enhanced Intracellular Survival of the Pathogen.

    Science.gov (United States)

    Czyż, Daniel M; Willett, Jonathan W; Crosson, Sean

    2017-08-01

    Intracellular bacterial pathogens exploit host cell resources to replicate and survive inside the host. Targeting these host systems is one promising approach to developing novel antimicrobials to treat intracellular infections. We show that human macrophage-like cells infected with Brucella abortus undergo a metabolic shift characterized by attenuated tricarboxylic acid cycle metabolism, reduced amino acid consumption, altered mitochondrial localization, and increased lactate production. This shift to an aerobic glycolytic state resembles the Warburg effect, a change in energy production that is well described in cancer cells and also occurs in activated inflammatory cells. B. abortus efficiently uses lactic acid as its sole carbon and energy source and requires the ability to metabolize lactate for normal survival in human macrophage-like cells. We demonstrate that chemical inhibitors of host glycolysis and lactate production do not affect in vitro growth of B. abortus in axenic culture but decrease its survival in the intracellular niche. Our data support a model in which infection shifts host metabolism to a Warburg-like state, and B. abortus uses this change in metabolism to promote intracellular survival. Pharmacological perturbation of these features of host cell metabolism may be a useful strategy to inhibit infection by intracellular pathogens. IMPORTANCE Brucella spp. are intracellular bacterial pathogens that cause disease in a range of mammals, including livestock. Transmission from livestock to humans is common and can lead to chronic human disease. Human macrophage-like cells infected with Brucella abortus undergo a Warburg-like metabolic shift to an aerobic glycolytic state where the host cells produce lactic acid and have reduced amino acid catabolism. We provide evidence that the pathogen can exploit this change in host metabolism to support growth and survival in the intracellular niche. Drugs that inhibit this shift in host cell metabolism

  20. Diverse mechanisms of metaeffector activity in an intracellular bacterial pathogen, Legionella pneumophila.

    Science.gov (United States)

    Urbanus, Malene L; Quaile, Andrew T; Stogios, Peter J; Morar, Mariya; Rao, Chitong; Di Leo, Rosa; Evdokimova, Elena; Lam, Mandy; Oatway, Christina; Cuff, Marianne E; Osipiuk, Jerzy; Michalska, Karolina; Nocek, Boguslaw P; Taipale, Mikko; Savchenko, Alexei; Ensminger, Alexander W

    2016-12-16

    Pathogens deliver complex arsenals of translocated effector proteins to host cells during infection, but the extent to which these proteins are regulated once inside the eukaryotic cell remains poorly defined. Among all bacterial pathogens, Legionella pneumophila maintains the largest known set of translocated substrates, delivering over 300 proteins to the host cell via its Type IVB, Icm/Dot translocation system. Backed by a few notable examples of effector-effector regulation in L. pneumophila, we sought to define the extent of this phenomenon through a systematic analysis of effector-effector functional interaction. We used Saccharomyces cerevisiae, an established proxy for the eukaryotic host, to query > 108,000 pairwise genetic interactions between two compatible expression libraries of ~330 L. pneumophila-translocated substrates. While capturing all known examples of effector-effector suppression, we identify fourteen novel translocated substrates that suppress the activity of other bacterial effectors and one pair with synergistic activities. In at least nine instances, this regulation is direct-a hallmark of an emerging class of proteins called metaeffectors, or "effectors of effectors". Through detailed structural and functional analysis, we show that metaeffector activity derives from a diverse range of mechanisms, shapes evolution, and can be used to reveal important aspects of each cognate effector's function. Metaeffectors, along with other, indirect, forms of effector-effector modulation, may be a common feature of many intracellular pathogens-with unrealized potential to inform our understanding of how pathogens regulate their interactions with the host cell. © 2016 The Authors. Published under the terms of the CC BY 4.0 license.

  1. Differential divergences of obligately insect-pathogenic Entomophthora species from fly and aphid hosts.

    Science.gov (United States)

    Jensen, Annette Bruun; Eilenberg, Jørgen; López Lastra, Claudia

    2009-11-01

    Three DNA regions (ITS 1, LSU rRNA and GPD) of isolates from the insect-pathogenic fungus genus Entomophthora originating from different fly (Diptera) and aphid (Hemiptera) host taxa were sequenced. The results documented a large genetic diversity among the fly-pathogenic Entomophthora and only minor differences among aphid-pathogenic Entomophthora. The evolutionary time of divergence of the fly and the aphid host taxa included cannot account for this difference. The host-driven divergence of Entomophthora, therefore, has been much greater in flies than in aphids. Host-range differences or a recent host shift to aphid are possible explanations.

  2. Search for microRNAs expressed by intracellular bacterial pathogens in infected mammalian cells.

    Science.gov (United States)

    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.

  3. Search for microRNAs expressed by intracellular bacterial pathogens in infected mammalian cells.

    Directory of Open Access Journals (Sweden)

    Yuki Furuse

    Full Text Available 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.

  4. NK Cell-Mediated Regulation of Protective Memory Responses against Intracellular Ehrlichial Pathogens.

    Directory of Open Access Journals (Sweden)

    Samar Habib

    Full Text Available Ehrlichiae are gram-negative obligate intracellular bacteria that cause potentially fatal human monocytic ehrlichiosis. We previously showed that natural killer (NK cells play a critical role in host defense against Ehrlichia during primary infection. However, the contribution of NK cells to the memory response against Ehrlichia remains elusive. Primary infection of C57BL/6 mice with Ehrlichia muris provides long-term protection against a second challenge with the highly virulent Ixodes ovatus Ehrlichia (IOE, which ordinarily causes fatal disease in naïve mice. Here, we show that the depletion of NK cells in E. muris-primed mice abrogates the protective memory response against IOE. Approximately, 80% of NK cell-depleted E. muris-primed mice succumbed to lethal IOE infection on days 8-10 after IOE infection, similar to naïve mice infected with the same dose of IOE. The lack of a recall response in NK cell-depleted mice correlated with an increased bacterial burden, extensive liver injury, decreased frequency of Ehrlichia-specific IFN-γ-producing memory CD4+ and CD8+ T-cells, and a low titer of Ehrlichia-specific antibodies. Intraperitoneal infection of mice with E. muris resulted in the production of IL-15, IL-12, and IFN-γ as well as an expansion of activated NKG2D+ NK cells. The adoptive transfer of purified E. muris-primed hepatic and splenic NK cells into Rag2-/-Il2rg-/- recipient mice provided protective immunity against challenge with E. muris. Together, these data suggest that E. muris-induced memory-like NK cells, which contribute to the protective, recall response against Ehrlichia.

  5. Molecular evolutionary consequences of niche restriction in Francisella tularensis, a facultative intracellular pathogen.

    Directory of Open Access Journals (Sweden)

    Pär Larsson

    2009-06-01

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

  6. Perforin-2 is essential for intracellular defense of parenchymal cells and phagocytes against pathogenic bacteria

    Science.gov (United States)

    McCormack, Ryan M; de Armas, Lesley R; Shiratsuchi, Motoaki; Fiorentino, Desiree G; Olsson, Melissa L; Lichtenheld, Mathias G; Morales, Alejo; Lyapichev, Kirill; Gonzalez, Louis E; Strbo, Natasa; Sukumar, Neelima; Stojadinovic, Olivera; Plano, Gregory V; Munson, George P; Tomic-Canic, Marjana; Kirsner, Robert S; Russell, David G; Podack, Eckhard R

    2015-01-01

    Perforin-2 (MPEG1) is a pore-forming, antibacterial protein with broad-spectrum activity. Perforin-2 is expressed constitutively in phagocytes and inducibly in parenchymal, tissue-forming cells. In vitro, Perforin-2 prevents the intracellular replication and proliferation of bacterial pathogens in these cells. Perforin-2 knockout mice are unable to control the systemic dissemination of methicillin-resistant Staphylococcus aureus (MRSA) or Salmonella typhimurium and perish shortly after epicutaneous or orogastric infection respectively. In contrast, Perforin-2-sufficient littermates clear the infection. Perforin-2 is a transmembrane protein of cytosolic vesicles -derived from multiple organelles- that translocate to and fuse with bacterium containing vesicles. Subsequently, Perforin-2 polymerizes and forms large clusters of 100 Å pores in the bacterial surface with Perforin-2 cleavage products present in bacteria. Perforin-2 is also required for the bactericidal activity of reactive oxygen and nitrogen species and hydrolytic enzymes. Perforin-2 constitutes a novel and apparently essential bactericidal effector molecule of the innate immune system. DOI: http://dx.doi.org/10.7554/eLife.06508.001 PMID:26402460

  7. Metabolic Cooperation of Glucose and Glutamine Is Essential for the Lytic Cycle of Obligate Intracellular Parasite Toxoplasma gondii.

    Science.gov (United States)

    Nitzsche, Richard; Zagoriy, Vyacheslav; Lucius, Richard; Gupta, Nishith

    2016-01-01

    Toxoplasma gondii is a widespread protozoan parasite infecting nearly all warm-blooded organisms. Asexual reproduction of the parasite within its host cells is achieved by consecutive lytic cycles, which necessitates biogenesis of significant energy and biomass. Here we show that glucose and glutamine are the two major physiologically important nutrients used for the synthesis of macromolecules (ATP, nucleic acid, proteins, and lipids) in T. gondii, and either of them is sufficient to ensure the parasite survival. The parasite can counteract genetic ablation of its glucose transporter by increasing the flux of glutamine-derived carbon through the tricarboxylic acid cycle and by concurrently activating gluconeogenesis, which guarantee a continued biogenesis of ATP and biomass for host-cell invasion and parasite replication, respectively. In accord, a pharmacological inhibition of glutaminolysis or oxidative phosphorylation arrests the lytic cycle of the glycolysis-deficient mutant, which is primarily a consequence of impaired invasion due to depletion of ATP. Unexpectedly, however, intracellular parasites continue to proliferate, albeit slower, notwithstanding a simultaneous deprivation of glucose and glutamine. A growth defect in the glycolysis-impaired mutant is caused by a compromised synthesis of lipids, which cannot be counterbalanced by glutamine but can be restored by acetate. Consistently, supplementation of parasite cultures with exogenous acetate can amend the lytic cycle of the glucose transport mutant. Such plasticity in the parasite's carbon flux enables a growth-and-survival trade-off in assorted nutrient milieus, which may underlie the promiscuous survival of T. gondii tachyzoites in diverse host cells. Our results also indicate a convergence of parasite metabolism with cancer cells. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. Metabolic Cooperation of Glucose and Glutamine Is Essential for the Lytic Cycle of Obligate Intracellular Parasite Toxoplasma gondii*

    Science.gov (United States)

    Nitzsche, Richard; Zagoriy, Vyacheslav; Lucius, Richard; Gupta, Nishith

    2016-01-01

    Toxoplasma gondii is a widespread protozoan parasite infecting nearly all warm-blooded organisms. Asexual reproduction of the parasite within its host cells is achieved by consecutive lytic cycles, which necessitates biogenesis of significant energy and biomass. Here we show that glucose and glutamine are the two major physiologically important nutrients used for the synthesis of macromolecules (ATP, nucleic acid, proteins, and lipids) in T. gondii, and either of them is sufficient to ensure the parasite survival. The parasite can counteract genetic ablation of its glucose transporter by increasing the flux of glutamine-derived carbon through the tricarboxylic acid cycle and by concurrently activating gluconeogenesis, which guarantee a continued biogenesis of ATP and biomass for host-cell invasion and parasite replication, respectively. In accord, a pharmacological inhibition of glutaminolysis or oxidative phosphorylation arrests the lytic cycle of the glycolysis-deficient mutant, which is primarily a consequence of impaired invasion due to depletion of ATP. Unexpectedly, however, intracellular parasites continue to proliferate, albeit slower, notwithstanding a simultaneous deprivation of glucose and glutamine. A growth defect in the glycolysis-impaired mutant is caused by a compromised synthesis of lipids, which cannot be counterbalanced by glutamine but can be restored by acetate. Consistently, supplementation of parasite cultures with exogenous acetate can amend the lytic cycle of the glucose transport mutant. Such plasticity in the parasite's carbon flux enables a growth-and-survival trade-off in assorted nutrient milieus, which may underlie the promiscuous survival of T. gondii tachyzoites in diverse host cells. Our results also indicate a convergence of parasite metabolism with cancer cells. PMID:26518878

  9. Dual Targeting of Intracellular Pathogenic Bacteria with a Cleavable Conjugate of Kanamycin and an Antibacterial Cell-Penetrating Peptide.

    Science.gov (United States)

    Brezden, Anna; Mohamed, Mohamed F; Nepal, Manish; Harwood, John S; Kuriakose, Jerrin; Seleem, Mohamed N; Chmielewski, Jean

    2016-08-31

    Bacterial infection caused by intracellular pathogens, such as Mycobacterium, Salmonella, and Brucella, is a burgeoning global health epidemic that necessitates urgent action. However, the therapeutic value of a number of antibiotics, including aminoglycosides, against intracellular pathogenic bacteria is compromised due to their inability to traverse eukaryotic membranes. For this significant problem to be addressed, a cleavable conjugate of the antibiotic kanamycin and a nonmembrane lytic, broad-spectrum antimicrobial peptide with efficient mammalian cell penetration, P14LRR, was prepared. This approach allows kanamycin to enter mammalian cells as a conjugate linked via a tether that breaks down in the reducing environment within cells. Potent antimicrobial activity of the P14KanS conjugate was demonstrated in vitro, and this reducible conjugate effectively cleared intracellular pathogenic bacteria within macrophages more potently than that of a conjugate lacking the disulfide moiety. Notably, successful clearance of Mycobacterium tuberculosis within macrophages was observed with the dual antibiotic conjugate, and Salmonella levels were significantly reduced in an in vivo Caenorhabditis elegans model.

  10. Pursuing Intracellular Pathogens with Hyaluronan. From a 'Pro-Infection' Polymer to a Biomaterial for 'Trojan Horse' Systems.

    Science.gov (United States)

    Montanari, Elita; Di Meo, Chiara; Oates, Angela; Coviello, Tommasina; Matricardi, Pietro

    2018-04-18

    Hyaluronan (HA) is among the most important bioactive polymers in mammals, playing a key role in a number of biological functions. In the last decades, it has been increasingly studied as a biomaterial for drug delivery systems, thanks to its physico-chemical features and ability to target and enter certain cells. The most important receptor of HA is ‘Cluster of Differentiation 44’ (CD44), a cell surface glycoprotein over-expressed by a number of cancers and heavily involved in HA endocytosis. Moreover, CD44 is highly expressed by keratinocytes, activated macrophages and fibroblasts, all of which can act as ‘reservoirs’ for intracellular pathogens. Interestingly, both CD44 and HA appear to play a key role for the invasion and persistence of such microorganisms within the cells. As such, HA is increasingly recognised as a potential target for nano-carriers development, to pursuit and target intracellular pathogens, acting as a ‘Trojan Horse’. This review describes the biological relationship between HA, CD44 and the entry and survival of a number of pathogens within the cells and the subsequent development of HA-based nano-carriers for enhancing the intracellular activity of antimicrobials.

  11. Identification and validation of reference genes for qRT-PCR studies of the obligate aphid pathogenic fungus Pandora neoaphidis during different developmental stages

    OpenAIRE

    Zhang, Shutao; Chen, Chun; Xie, Tingna; Ye, Sudan

    2017-01-01

    The selection of stable reference genes is a critical step for the accurate quantification of gene expression. To identify and validate the reference genes in Pandora neoaphidis-an obligate aphid pathogenic fungus-the expression of 13classical candidate reference genes were evaluated by quantitative real-time reverse transcriptase polymerase chain reaction(qPCR) at four developmental stages (conidia, conidia with germ tubes, short hyphae and elongated hyphae). Four statistical algorithms, inc...

  12. Eosinophils subvert host resistance to an intracellular pathogen by instigating non-protective IL-4 in CCR2-/- mice.

    Science.gov (United States)

    Verma, A H; Bueter, C L; Rothenberg, M E; Deepe, G S

    2017-01-01

    Eosinophils contribute to type II immune responses in helminth infections and allergic diseases; however, their influence on intracellular pathogens is less clear. We previously reported that CCR2 -/- mice exposed to the intracellular fungal pathogen Histoplasma capsulatum exhibit dampened immunity caused by an early exaggerated interleukin (IL)-4 response. We sought to identify the cellular source promulgating IL-4 in infected mutant animals. Eosinophils were the principal instigators of non-protective IL-4 and depleting this granulocyte population improved fungal clearance in CCR2 -/- animals. The deleterious impact of eosinophilia on mycosis was also recapitulated in transgenic animals overexpressing eosinophils. Mechanistic examination of IL-4 induction revealed that phagocytosis of H. capsulatum via the pattern recognition receptor complement receptor (CR) 3 triggered the heightened IL-4 response in murine eosinophils. This phenomenon was conserved in human eosinophils; exposure of cells to the fungal pathogen elicited a robust IL-4 response. Thus, our findings elucidate a detrimental attribute of eosinophil biology in fungal infections that could potentially trigger a collapse in host defenses by instigating type II immunity.

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

    Science.gov (United States)

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

    2012-01-01

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

  14. Hyperspectral Imaging Using Intracellular Spies: Quantitative Real-Time Measurement of Intracellular Parameters In Vivo during Interaction of the Pathogenic Fungus Aspergillus fumigatus with Human Monocytes.

    Directory of Open Access Journals (Sweden)

    Sara Mohebbi

    Full Text Available Hyperspectral imaging (HSI is a technique based on the combination of classical spectroscopy and conventional digital image processing. It is also well suited for the biological assays and quantitative real-time analysis since it provides spectral and spatial data of samples. The method grants detailed information about a sample by recording the entire spectrum in each pixel of the whole image. We applied HSI to quantify the constituent pH variation in a single infected apoptotic monocyte as a model system. Previously, we showed that the human-pathogenic fungus Aspergillus fumigatus conidia interfere with the acidification of phagolysosomes. Here, we extended this finding to monocytes and gained a more detailed analysis of this process. Our data indicate that melanised A. fumigatus conidia have the ability to interfere with apoptosis in human monocytes as they enable the apoptotic cell to recover from mitochondrial acidification and to continue with the cell cycle. We also showed that this ability of A. fumigatus is dependent on the presence of melanin, since a non-pigmented mutant did not stop the progression of apoptosis and consequently, the cell did not recover from the acidic pH. By conducting the current research based on the HSI, we could measure the intracellular pH in an apoptotic infected human monocyte and show the pattern of pH variation during 35 h of measurements. As a conclusion, we showed the importance of melanin for determining the fate of intracellular pH in a single apoptotic cell.

  15. Small non-coding RNAs: new insights in modulation of host immune response by intracellular bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Waqas Ahmed

    2016-10-01

    Full Text Available Pathogenic bacteria possess intricate regulatory networks that temporally control the production of virulence factors, and enable the bacteria to survive and proliferate within host cell. Small non-coding RNAs (sRNAs have been identified as important regulators of gene expression in diverse biological contexts. Recent research has shown bacterial sRNAs involved in growth and development, cell proliferation, differentiation, metabolism, cell signaling and immune response through regulating protein–protein interactions or via their ability to base pair with RNA and DNA. In this review, we provide a brief overview of mechanism of action employed by immune-related sRNAs, their known functions in immunity, and how they can be integrated into regulatory circuits that govern virulence, which will facilitates to understand pathogenesis and the development of novel, more effective therapeutic approaches to treat infections caused by intracellular bacterial pathogens.

  16. Molecular mechanisms of cell-cell spread of intracellular bacterial pathogens.

    Science.gov (United States)

    Ireton, Keith

    2013-07-17

    Several bacterial pathogens, including Listeria monocytogenes, Shigella flexneri and Rickettsia spp., have evolved mechanisms to actively spread within human tissues. Spreading is initiated by the pathogen-induced recruitment of host filamentous (F)-actin. F-actin forms a tail behind the microbe, propelling it through the cytoplasm. The motile pathogen then encounters the host plasma membrane, forming a bacterium-containing protrusion that is engulfed by an adjacent cell. Over the past two decades, much progress has been made in elucidating mechanisms of F-actin tail formation. Listeria and Shigella produce tails of branched actin filaments by subverting the host Arp2/3 complex. By contrast, Rickettsia forms tails with linear actin filaments through a bacterial mimic of eukaryotic formins. Compared with F-actin tail formation, mechanisms controlling bacterial protrusions are less well understood. However, recent findings have highlighted the importance of pathogen manipulation of host cell-cell junctions in spread. Listeria produces a soluble protein that enhances bacterial protrusions by perturbing tight junctions. Shigella protrusions are engulfed through a clathrin-mediated pathway at 'tricellular junctions'--specialized membrane regions at the intersection of three epithelial cells. This review summarizes key past findings in pathogen spread, and focuses on recent developments in actin-based motility and the formation and internalization of bacterial protrusions.

  17. Pathogenic adaptation of intracellular bacteria by rewiring a cis-regulatory input function.

    Science.gov (United States)

    Osborne, Suzanne E; Walthers, Don; Tomljenovic, Ana M; Mulder, David T; Silphaduang, Uma; Duong, Nancy; Lowden, Michael J; Wickham, Mark E; Waller, Ross F; Kenney, Linda J; Coombes, Brian K

    2009-03-10

    The acquisition of DNA by horizontal gene transfer enables bacteria to adapt to previously unexploited ecological niches. Although horizontal gene transfer and mutation of protein-coding sequences are well-recognized forms of pathogen evolution, the evolutionary significance of cis-regulatory mutations in creating phenotypic diversity through altered transcriptional outputs is not known. We show the significance of regulatory mutation for pathogen evolution by mapping and then rewiring a cis-regulatory module controlling a gene required for murine typhoid. Acquisition of a binding site for the Salmonella pathogenicity island-2 regulator, SsrB, enabled the srfN gene, ancestral to the Salmonella genus, to play a role in pathoadaptation of S. typhimurium to a host animal. We identified the evolved cis-regulatory module and quantified the fitness gain that this regulatory output accrues for the bacterium using competitive infections of host animals. Our findings highlight a mechanism of pathogen evolution involving regulatory mutation that is selected because of the fitness advantage the new regulatory output provides the incipient clones.

  18. The compact genome of the plant pathogen Plasmodiophora brassicae is adapted to intracellular interactions with host Brassica spp.

    Science.gov (United States)

    Rolfe, Stephen A; Strelkov, Stephen E; Links, Matthew G; Clarke, Wayne E; Robinson, Stephen J; Djavaheri, Mohammad; Malinowski, Robert; Haddadi, Parham; Kagale, Sateesh; Parkin, Isobel A P; Taheri, Ali; Borhan, M Hossein

    2016-03-31

    The protist Plasmodiophora brassicae is a soil-borne pathogen of cruciferous species and the causal agent of clubroot disease of Brassicas including agriculturally important crops such as canola/rapeseed (Brassica napus). P. brassicae has remained an enigmatic plant pathogen and is a rare example of an obligate biotroph that resides entirely inside the host plant cell. The pathogen is the cause of severe yield losses and can render infested fields unsuitable for Brassica crop growth due to the persistence of resting spores in the soil for up to 20 years. To provide insight into the biology of the pathogen and its interaction with its primary host B. napus, we produced a draft genome of P. brassicae pathotypes 3 and 6 (Pb3 and Pb6) that differ in their host range. Pb3 is highly virulent on B. napus (but also infects other Brassica species) while Pb6 infects only vegetable Brassica crops. Both the Pb3 and Pb6 genomes are highly compact, each with a total size of 24.2 Mb, and contain less than 2 % repetitive DNA. Clustering of genome-wide single nucleotide polymorphisms (SNP) of Pb3, Pb6 and three additional re-sequenced pathotypes (Pb2, Pb5 and Pb8) shows a high degree of correlation of cluster grouping with host range. The Pb3 genome features significant reduction of intergenic space with multiple examples of overlapping untranslated regions (UTRs). Dependency on the host for essential nutrients is evident from the loss of genes for the biosynthesis of thiamine and some amino acids and the presence of a wide range of transport proteins, including some unique to P. brassicae. The annotated genes of Pb3 include those with a potential role in the regulation of the plant growth hormones cytokinin and auxin. The expression profile of Pb3 genes, including putative effectors, during infection and their potential role in manipulation of host defence is discussed. The P. brassicae genome sequence reveals a compact genome, a dependency of the pathogen on its host for some

  19. Intracellular persisting Staphylococcus aureus is the major pathogen in recurrent tonsillitis.

    Directory of Open Access Journals (Sweden)

    Andreas E Zautner

    Full Text Available BACKGROUND: The two major indications for tonsillectomy are recurrent tonsillitis (RT and peritonsillar abscess (PTA. Unlike PTAs, which are primarily treated surgically, RT is often cured by tonsillectomy only after a series of failed drug therapy attempts. Although the bacteriological background of RT has been studied, the reason for the lack of success of conservative therapeutic approaches is not well understood. METHODS: In a prospective study, tonsil specimens from 130 RT patients and 124 PTA patients were examined for the presence of extra- and intracellular bacteria using antibiotic protection assays. Staphylococcus aureus isolates from RT patients were characterized by pulsed-field gel electrophoresis (PFGE, spa-typing and MSCRAMM-gene-PCR. Their ability for biofilm formation was tested and their cell invasiveness was confirmed by a flow cytometric invasion assay (FACS, fluorescent in situ hybridization (FISH and immunohistochemistry. FINDINGS: S. aureus was the predominant species (57.7% in RT patients, whereas Streptococcus pyogenes was most prevalent (20.2% in PTA patients. Three different assays (FACS, FISH, antibiotic protection assay showed that nearly all RT-associated S. aureus strains were located inside tonsillar cells. Correspondingly, the results of the MSCRAMM-gene-PCRs confirmed that 87% of these S. aureus isolates were invasive strains and not mere colonizers. Based upon PFGE analyses of genomic DNA and on spa-gene typing the vast majority of the S. aureus isolates belonged to different clonal lineages. CONCLUSIONS: Our results demonstrate that intracellular residing S. aureus is the most common cause of RT and indicate that S. aureus uses this location to survive the effects of antibiotics and the host immune response. A German translation of the Abstract is provided as supplementary material (Abstract S1.

  20. The Equine Antimicrobial Peptide eCATH1 Is Effective against the Facultative Intracellular Pathogen Rhodococcus equi in Mice

    Science.gov (United States)

    Schlusselhuber, Margot; Torelli, Riccardo; Martini, Cecilia; Leippe, Matthias; Cattoir, Vincent; Leclercq, Roland; Laugier, Claire; Grötzinger, Joachim; Sanguinetti, Maurizio

    2013-01-01

    Rhodococcus equi, the causal agent of rhodococcosis, is a major pathogen of foals and is also responsible for severe infections in immunocompromised humans. Of great concern, strains resistant to currently used antibiotics have emerged. As the number of drugs that are efficient in vivo is limited because of the intracellular localization of the bacterium inside macrophages, new active but cell-permeant drugs will be needed in the near future. In the present study, we evaluated, by in vitro and ex vivo experiments, the ability of the alpha-helical equine antimicrobial peptide eCATH1 to kill intracellular bacterial cells. Moreover, the therapeutic potential of the peptide was assessed in experimental rhodococcosis induced in mice, while the in vivo toxicity was evaluated by behavioral and histopathological analysis. The study revealed that eCATH1 significantly reduced the number of bacteria inside macrophages. Furthermore, the bactericidal potential of the peptide was maintained in vivo at doses that appeared to have no visible deleterious effects for the mice even after 7 days of treatment. Indeed, daily subcutaneous injections of 1 mg/kg body weight of eCATH1 led to a significant reduction of the bacterial load in organs comparable to that obtained after treatment with 10 mg/kg body weight of rifampin. Interestingly, the combination of the peptide with rifampin showed a synergistic interaction in both ex vivo and in vivo experiments. These results emphasize the therapeutic potential that eCATH1 represents in the treatment of rhodococcosis. PMID:23817377

  1. Intracellular Growth Is Dependent on Tyrosine Catabolism in the Dimorphic Fungal Pathogen Penicillium marneffei

    Science.gov (United States)

    Boyce, Kylie J.; McLauchlan, Alisha; Schreider, Lena; Andrianopoulos, Alex

    2015-01-01

    During infection, pathogens must utilise the available nutrient sources in order to grow while simultaneously evading or tolerating the host’s defence systems. Amino acids are an important nutritional source for pathogenic fungi and can be assimilated from host proteins to provide both carbon and nitrogen. The hpdA gene of the dimorphic fungus Penicillium marneffei, which encodes an enzyme which catalyses the second step of tyrosine catabolism, was identified as up-regulated in pathogenic yeast cells. As well as enabling the fungus to acquire carbon and nitrogen, tyrosine is also a precursor in the formation of two types of protective melanin; DOPA melanin and pyomelanin. Chemical inhibition of HpdA in P. marneffei inhibits ex vivo yeast cell production suggesting that tyrosine is a key nutrient source during infectious growth. The genes required for tyrosine catabolism, including hpdA, are located in a gene cluster and the expression of these genes is induced in the presence of tyrosine. A gene (hmgR) encoding a Zn(II)2-Cys6 binuclear cluster transcription factor is present within the cluster and is required for tyrosine induced expression and repression in the presence of a preferred nitrogen source. AreA, the GATA-type transcription factor which regulates the global response to limiting nitrogen conditions negatively regulates expression of cluster genes in the absence of tyrosine and is required for nitrogen metabolite repression. Deletion of the tyrosine catabolic genes in the cluster affects growth on tyrosine as either a nitrogen or carbon source and affects pyomelanin, but not DOPA melanin, production. In contrast to other genes of the tyrosine catabolic cluster, deletion of hpdA results in no growth within macrophages. This suggests that the ability to catabolise tyrosine is not required for macrophage infection and that HpdA has an additional novel role to that of tyrosine catabolism and pyomelanin production during growth in host cells. PMID:25812137

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-01

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

  4. Neutrophils Contribute to the Protection Conferred by ArtinM against Intracellular Pathogens: A Study on Leishmania major.

    Science.gov (United States)

    Ricci-Azevedo, Rafael; Oliveira, Aline Ferreira; Conrado, Marina C A V; Carvalho, Fernanda Caroline; Roque-Barreira, Maria Cristina

    2016-04-01

    ArtinM, a D-mannose binding lectin from Artocarpus heterophyllus, has immunomodulatory activities through its interaction with N-glycans of immune cells, culminating with the establishment of T helper type 1 (Th1) immunity. This interaction protects mice against intracellular pathogens, including Leishmania major and Leishmania amazonensis. ArtinM induces neutrophils activation, which is known to account for both resistance to pathogens and host tissue injury. Although exacerbated inflammation was not observed in ArtinM-treated animals, assessment of neutrophil responses to ArtinM is required to envisage its possible application to design a novel immunomodulatory agent based on carbohydrate recognition. Herein, we focus on the mechanisms through which neutrophils contribute to ArtinM-induced protection against Leishmania, without exacerbating inflammation. For this purpose, human neutrophils treated with ArtinM and infected with Leishmania major were analyzed together with untreated and uninfected controls, based on their ability to eliminate the parasite, release cytokines, degranulate, produce reactive oxygen species (ROS), form neutrophil extracellular traps (NETs) and change life span. We demonstrate that ArtinM-stimulated neutrophils enhanced L. major clearance and at least duplicated tumor necrosis factor (TNF) and interleukin-1beta (IL-1β) release; otherwise, transforming growth factor-beta (TGF-β) production was reduced by half. Furthermore, ROS production and cell degranulation were augmented. The life span of ArtinM-stimulated neutrophils decreased and they did not form NETs when infected with L. major. We postulate that the enhanced leishmanicidal ability of ArtinM-stimulated neutrophils is due to augmented release of inflammatory cytokines, ROS production, and cell degranulation, whereas host tissue integrity is favored by their shortened life span and the absence of NET formation. Our results reinforce the idea that ArtinM may be considered an

  5. Neutrophils Contribute to the Protection Conferred by ArtinM against Intracellular Pathogens: A Study on Leishmania major.

    Directory of Open Access Journals (Sweden)

    Rafael Ricci-Azevedo

    2016-04-01

    Full Text Available ArtinM, a D-mannose binding lectin from Artocarpus heterophyllus, has immunomodulatory activities through its interaction with N-glycans of immune cells, culminating with the establishment of T helper type 1 (Th1 immunity. This interaction protects mice against intracellular pathogens, including Leishmania major and Leishmania amazonensis. ArtinM induces neutrophils activation, which is known to account for both resistance to pathogens and host tissue injury. Although exacerbated inflammation was not observed in ArtinM-treated animals, assessment of neutrophil responses to ArtinM is required to envisage its possible application to design a novel immunomodulatory agent based on carbohydrate recognition. Herein, we focus on the mechanisms through which neutrophils contribute to ArtinM-induced protection against Leishmania, without exacerbating inflammation. For this purpose, human neutrophils treated with ArtinM and infected with Leishmania major were analyzed together with untreated and uninfected controls, based on their ability to eliminate the parasite, release cytokines, degranulate, produce reactive oxygen species (ROS, form neutrophil extracellular traps (NETs and change life span. We demonstrate that ArtinM-stimulated neutrophils enhanced L. major clearance and at least duplicated tumor necrosis factor (TNF and interleukin-1beta (IL-1β release; otherwise, transforming growth factor-beta (TGF-β production was reduced by half. Furthermore, ROS production and cell degranulation were augmented. The life span of ArtinM-stimulated neutrophils decreased and they did not form NETs when infected with L. major. We postulate that the enhanced leishmanicidal ability of ArtinM-stimulated neutrophils is due to augmented release of inflammatory cytokines, ROS production, and cell degranulation, whereas host tissue integrity is favored by their shortened life span and the absence of NET formation. Our results reinforce the idea that ArtinM may be

  6. Vacuolar zinc transporter Zrc1 is required for detoxification of excess intracellular zinc in the human fungal pathogen Cryptococcus neoformans.

    Science.gov (United States)

    Cho, Minsu; Hu, Guanggan; Caza, Mélissa; Horianopoulos, Linda C; Kronstad, James W; Jung, Won Hee

    2018-01-01

    Zinc is an important transition metal in all living organisms and is required for numerous biological processes. However, excess zinc can also be toxic to cells and cause cellular stress. In the model fungus Saccharomyces cerevisiae, a vacuolar zinc transporter, Zrc1, plays important roles in the storage and detoxification of excess intracellular zinc to protect the cell. In this study, we identified an ortholog of the S. cerevisiae ZRC1 gene in the human fungal pathogen Cryptococcus neoformans. Zrc1 was localized in the vacuolar membrane in C. neoformans, and a mutant lacking ZRC1 showed significant growth defects under high-zinc conditions. These results suggested a role for Zrc1 in zinc detoxification. However, contrary to our expectation, the expression of Zrc1 was induced in cells grown in zinc-limited conditions and decreased upon the addition of zinc. These expression patterns were similar to those of Zip1, the high-affinity zinc transporter in the plasma membrane of C. neoformans. Furthermore, we used the zrc1 mutant in a murine model of cryptococcosis to examine whether a mammalian host could inhibit the survival of C. neoformans using zinc toxicity. We found that the mutant showed no difference in virulence compared with the wildtype strain. This result suggests that Zrc1-mediated zinc detoxification is not required for the virulence of C. neoformans, and imply that zinc toxicity may not be an important aspect of the host immune response to the fungus.

  7. A rapid genotyping method for an obligate fungal pathogen, Puccinia striiformis f.sp. tritici, based on DNA extraction from infected leaf and Multiplex PCR genotyping

    Directory of Open Access Journals (Sweden)

    Enjalbert Jérôme

    2011-07-01

    Full Text Available Abstract Background Puccinia striiformis f.sp. tritici (PST, an obligate fungal pathogen causing wheat yellow/stripe rust, a serious disease, has been used to understand the evolution of crop pathogen using molecular markers. However, numerous questions regarding its evolutionary history and recent migration routes still remains to be addressed, which need the genotyping of a large number of isolates, a process that is limited by both DNA extraction and genotyping methods. To address the two issues, we developed here a method for direct DNA extraction from infected leaves combined with optimized SSR multiplexing. Findings We report here an efficient protocol for direct fungal DNA extraction from infected leaves, avoiding the costly and time consuming step of spore multiplication. The genotyping strategy we propose, amplified a total of 20 SSRs in three Multiplex PCR reactions, which were highly polymorphic and were able to differentiate different PST populations with high efficiency and accuracy. Conclusion These two developments enabled a genotyping strategy that could contribute to the development of molecular epidemiology of yellow rust disease, both at a regional or worldwide scale.

  8. Identification and validation of reference genes for qRT-PCR studies of the obligate aphid pathogenic fungus Pandora neoaphidis during different developmental stages.

    Directory of Open Access Journals (Sweden)

    Shutao Zhang

    Full Text Available The selection of stable reference genes is a critical step for the accurate quantification of gene expression. To identify and validate the reference genes in Pandora neoaphidis-an obligate aphid pathogenic fungus-the expression of 13classical candidate reference genes were evaluated by quantitative real-time reverse transcriptase polymerase chain reaction(qPCR at four developmental stages (conidia, conidia with germ tubes, short hyphae and elongated hyphae. Four statistical algorithms, including geNorm, NormFinder, BestKeeper and Delta Ct method were used to rank putative reference genes according to their expression stability and indicate the best reference gene or combination of reference genes for accurate normalization. The analysis of comprehensive ranking revealed that ACT1and 18Swas the most stably expressed genes throughout the developmental stages. To further validate the suitability of the reference genes identified in this study, the expression of cell division control protein 25 (CDC25 and Chitinase 1(CHI1 genes were used to further confirm the validated candidate reference genes. Our study presented the first systematic study of reference gene(s selection for P. neoaphidis study and provided guidelines to obtain more accurate qPCR results for future developmental efforts.

  9. Identification and validation of reference genes for qRT-PCR studies of the obligate aphid pathogenic fungus Pandora neoaphidis during different developmental stages.

    Science.gov (United States)

    Zhang, Shutao; Chen, Chun; Xie, Tingna; Ye, Sudan

    2017-01-01

    The selection of stable reference genes is a critical step for the accurate quantification of gene expression. To identify and validate the reference genes in Pandora neoaphidis-an obligate aphid pathogenic fungus-the expression of 13classical candidate reference genes were evaluated by quantitative real-time reverse transcriptase polymerase chain reaction(qPCR) at four developmental stages (conidia, conidia with germ tubes, short hyphae and elongated hyphae). Four statistical algorithms, including geNorm, NormFinder, BestKeeper and Delta Ct method were used to rank putative reference genes according to their expression stability and indicate the best reference gene or combination of reference genes for accurate normalization. The analysis of comprehensive ranking revealed that ACT1and 18Swas the most stably expressed genes throughout the developmental stages. To further validate the suitability of the reference genes identified in this study, the expression of cell division control protein 25 (CDC25) and Chitinase 1(CHI1) genes were used to further confirm the validated candidate reference genes. Our study presented the first systematic study of reference gene(s) selection for P. neoaphidis study and provided guidelines to obtain more accurate qPCR results for future developmental efforts.

  10. Eosinophils Subvert Host Resistance to an Intracellular Pathogen by Instigating Non-Protective IL-4 in CCR2−/− Mice

    Science.gov (United States)

    Verma, Akash H.; Bueter, Chelsea L.; Rothenberg, Marc E.; Deepe, George S.

    2016-01-01

    Eosinophils contribute to type II immune responses in helminth infections and allergic diseases, however, their influence on intracellular pathogens is less clear. We previously reported that CCR2−/− mice exposed to the intracellular fungal pathogen Histoplasma capsulatum exhibit dampened immunity caused by an early exaggerated IL-4 response. We sought to identify the cellular source promulgating interleukin (IL)-4 in infected mutant animals. Eosinophils were the principal instigators of non-protective IL-4 and depleting this granulocyte population improved fungal clearance in CCR2−/− animals. The deleterious impact of eosinophilia on mycosis was also recapitulated in transgenic animals overexpressing eosinophils. Mechanistic examination of IL-4 induction revealed that phagocytosis of H. capsulatum via the pattern recognition receptor complement receptor (CR) 3 triggered the heightened IL-4 response in murine eosinophils. This phenomenon was conserved in human eosinophils; exposure of cells to the fungal pathogen elicited a robust IL-4 response. Thus, our findings elucidate a detrimental attribute of eosinophil biology in fungal infections that could potentially trigger a collapse in host defenses by instigating type II immunity. PMID:27049063

  11. Obliging children.

    Science.gov (United States)

    Lyons, Barry

    2011-01-01

    Children may sometimes undergo healthcare procedures that are not intended to improve their health status. Such interventions might include the use of young children as bone marrow donors or their enrolment in non-therapeutic research. One of the justifications used to legitimise these interventions is the premise that children have obligations to others; to their family in the case of related bone marrow transplantation, and to wider society in the case of non-therapeutic research. However, this 'obligation model' (the notion that children possess positive obligations to advance the health status of others) fails as a justificatory paradigm because it is based upon a confusion, identified by Hart, between two notions; that of 'being under an obligation to do something' and that of 'being obliged to do something'. Instead the 'obligation model' is a device employed to put a justificatory gloss upon a consequentialist decision-making process; removing the legitimising gloss allows for a more transparent look at the conflict between parental rights and an individual child's right to bodily integrity.

  12. Institutional obligation

    International Nuclear Information System (INIS)

    Rowan, S.S.; Berwager, S.D.

    1988-01-01

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

  13. Genome sequencing of the lizard parasite Leishmania tarentolae reveals loss of genes associated to the intracellular stage of human pathogenic species

    Science.gov (United States)

    Raymond, Frédéric; Boisvert, Sébastien; Roy, Gaétan; Ritt, Jean-François; Légaré, Danielle; Isnard, Amandine; Stanke, Mario; Olivier, Martin; Tremblay, Michel J.; Papadopoulou, Barbara; Ouellette, Marc; Corbeil, Jacques

    2012-01-01

    The Leishmania tarentolae Parrot-TarII strain genome sequence was resolved to an average 16-fold mean coverage by next-generation DNA sequencing technologies. This is the first non-pathogenic to humans kinetoplastid protozoan genome to be described thus providing an opportunity for comparison with the completed genomes of pathogenic Leishmania species. A high synteny was observed between all sequenced Leishmania species. A limited number of chromosomal regions diverged between L. tarentolae and L. infantum, while remaining syntenic to L. major. Globally, >90% of the L. tarentolae gene content was shared with the other Leishmania species. We identified 95 predicted coding sequences unique to L. tarentolae and 250 genes that were absent from L. tarentolae. Interestingly, many of the latter genes were expressed in the intracellular amastigote stage of pathogenic species. In addition, genes coding for products involved in antioxidant defence or participating in vesicular-mediated protein transport were underrepresented in L. tarentolae. In contrast to other Leishmania genomes, two gene families were expanded in L. tarentolae, namely the zinc metallo-peptidase surface glycoprotein GP63 and the promastigote surface antigen PSA31C. Overall, L. tarentolae's gene content appears better adapted to the promastigote insect stage rather than the amastigote mammalian stage. PMID:21998295

  14. Proteome profiling and functional classification of intracellular proteins from conidia of the human-pathogenic mold Aspergillus fumigatus.

    Science.gov (United States)

    Teutschbein, Janka; Albrecht, Daniela; Pötsch, Maria; Guthke, Reinhard; Aimanianda, Vishukumar; Clavaud, Cécile; Latgé, Jean-Paul; Brakhage, Axel A; Kniemeyer, Olaf

    2010-07-02

    Aspergillus fumigatus is a ubiquitously distributed filamentous fungus that has emerged as one of the most serious life-threatening pathogens in immunocompromised patients. The mechanisms for its pathogenicity are poorly understood. Here, we analyzed the proteome of dormant A. fumigatus conidia as the fungal entity having the initial contact with the host. Applying two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), we established a 2-D reference map of conidial proteins. By MALDI-TOF mass spectrometry, we identified a total number of 449 different proteins. We show that 57 proteins of our map are over-represented in resting conidia compared to mycelium. Enzymes involved in reactive oxygen intermediates (ROI) detoxification, pigment biosynthesis, and conidial rodlet layer formation were highly abundant in A. fumigatus spores and most probably account for their enormous stress resistance. Interestingly, pyruvate decarboxylase and alcohol dehydrogenase were detectable in dormant conidia, suggesting that alcoholic fermentation plays a role during dormancy or early germination. Moreover, we show that enzymes for rapid reactivation of protein biosynthesis and metabolic processes are preserved in resting conidia, which therefore feature the potential to immediately respond to an environmental stimulus by germination. The generated data lay the foundations for further proteomic analyses and a better understanding of fungal pathogenesis.

  15. The steroid catabolic pathway of the intracellular pathogen Rhodococcus equi is important for pathogenesis and a target for vaccine development.

    Directory of Open Access Journals (Sweden)

    R van der Geize

    2011-08-01

    Full Text Available Rhodococcus equi causes fatal pyogranulomatous pneumonia in foals and immunocompromised animals and humans. Despite its importance, there is currently no effective vaccine against the disease. The actinobacteria R. equi and the human pathogen Mycobacterium tuberculosis are related, and both cause pulmonary diseases. Recently, we have shown that essential steps in the cholesterol catabolic pathway are involved in the pathogenicity of M. tuberculosis. Bioinformatic analysis revealed the presence of a similar cholesterol catabolic gene cluster in R. equi. Orthologs of predicted M. tuberculosis virulence genes located within this cluster, i.e. ipdA (rv3551, ipdB (rv3552, fadA6 and fadE30, were identified in R. equi RE1 and inactivated. The ipdA and ipdB genes of R. equi RE1 appear to constitute the α-subunit and β-subunit, respectively, of a heterodimeric coenzyme A transferase. Mutant strains RE1ΔipdAB and RE1ΔfadE30, but not RE1ΔfadA6, were impaired in growth on the steroid catabolic pathway intermediates 4-androstene-3,17-dione (AD and 3aα-H-4α(3'-propionic acid-5α-hydroxy-7aβ-methylhexahydro-1-indanone (5α-hydroxy-methylhexahydro-1-indanone propionate; 5OH-HIP. Interestingly, RE1ΔipdAB and RE1ΔfadE30, but not RE1ΔfadA6, also displayed an attenuated phenotype in a macrophage infection assay. Gene products important for growth on 5OH-HIP, as part of the steroid catabolic pathway, thus appear to act as factors involved in the pathogenicity of R. equi. Challenge experiments showed that RE1ΔipdAB could be safely administered intratracheally to 2 to 5 week-old foals and oral immunization of foals even elicited a substantial protective immunity against a virulent R. equi strain. Our data show that genes involved in steroid catabolism are promising targets for the development of a live-attenuated vaccine against R. equi infections.

  16. TmpL, a transmembrane protein required for intracellular redox homeostasis and virulence in a plant and an animal fungal pathogen.

    Directory of Open Access Journals (Sweden)

    Kwang-Hyung Kim

    2009-11-01

    Full Text Available The regulation of intracellular levels of reactive oxygen species (ROS is critical for developmental differentiation and virulence of many pathogenic fungi. In this report we demonstrate that a novel transmembrane protein, TmpL, is necessary for regulation of intracellular ROS levels and tolerance to external ROS, and is required for infection of plants by the necrotroph Alternaria brassicicola and for infection of mammals by the human pathogen Aspergillus fumigatus. In both fungi, tmpL encodes a predicted hybrid membrane protein containing an AMP-binding domain, six putative transmembrane domains, and an experimentally-validated FAD/NAD(P-binding domain. Localization and gene expression analyses in A. brassicicola indicated that TmpL is associated with the Woronin body, a specialized peroxisome, and strongly expressed during conidiation and initial invasive growth in planta. A. brassicicola and A. fumigatus DeltatmpL strains exhibited abnormal conidiogenesis, accelerated aging, enhanced oxidative burst during conidiation, and hypersensitivity to oxidative stress when compared to wild-type or reconstituted strains. Moreover, A. brassicicola DeltatmpL strains, although capable of initial penetration, exhibited dramatically reduced invasive growth on Brassicas and Arabidopsis. Similarly, an A. fumigatus DeltatmpL mutant was dramatically less virulent than the wild-type and reconstituted strains in a murine model of invasive aspergillosis. Constitutive expression of the A. brassicicola yap1 ortholog in an A. brassicicola DeltatmpL strain resulted in high expression levels of genes associated with oxidative stress tolerance. Overexpression of yap1 in the DeltatmpL background complemented the majority of observed developmental phenotypic changes and partially restored virulence on plants. Yap1-GFP fusion strains utilizing the native yap1 promoter exhibited constitutive nuclear localization in the A. brassicicola DeltatmpL background. Collectively, we

  17. Mannose-binding lectin and l-ficolin polymorphisms in patients with community-acquired pneumonia caused by intracellular pathogens.

    Science.gov (United States)

    van Kempen, Gijs; Meijvis, Sabine; Endeman, Henrik; Vlaminckx, Bart; Meek, Bob; de Jong, Ben; Rijkers, Ger; Bos, Willem Jan

    2017-05-01

    Community-acquired pneumonia (CAP) is the leading infectious disease requiring hospitalization in the western world. Genetic variability affecting the host response to infection may play a role in susceptibility and outcome in patients with CAP. Mannose-binding lectin (MBL) and l-ficolin (l-FCN) are two important activators of the complement system and they can enhance phagocytosis by opsonization. In a prospective cohort of 505 Dutch patients with CAP and 227 control participants we studied whether polymorphisms in the MBL (MBL2) and FCN (FCN2) genes influenced susceptibility and outcome. No difference in frequency of these genotypes was found between patients with CAP in general and controls. However, the +6424G>T single nucleotide polymorphism (SNP) in FCN2 was more common in patients with a Coxiella burnetii pneumonia (P = 0·014). Moreover, the haplotypes coding for the highest MBL serum levels (YA/YA and YA/XA) predisposed to atypical pneumonia (C. burnetii, Legionella or Chlamydia species or Mycoplasma pneumoniae) compared with controls (P = 0·016). Furthermore, patients with these haplotypes were more often bacteraemic (P = 0·019). It can therefore be concluded that MBL2 and FCN2 polymorphisms are not major risk factors for CAP in general, but that the +6424G>T SNP in the FCN2 gene predisposes to C. burnetii pneumonia. In addition, patients with genotypes corresponding with high serum MBL levels are at risk for atypical pneumonia, possibly caused by enhanced phagocytosis, thereby promoting cell entry of these intracellular bacteria. © 2016 The Authors. Immunology Published by John Wiley & Sons Ltd.

  18. Infection of Drosophila suzukii with the obligate insect-pathogenic fungus Entomophthora muscae

    DEFF Research Database (Denmark)

    Becher, Paul G.; Jensen, Rasmus E.; Natsopoulou, Myrsini E.

    2018-01-01

    Physiological constraints restrict specialist pathogens from infecting new hosts. From an applied perspective, a narrow host range makes specialist pathogens interesting for targeting specific pest insects since they have minimal direct effects on non-target species. Entomopathogenic fungi of the...

  19. Natural history of zoonotic Ehrlichia species in the United States and discovery of a novel ehrlichial pathogen

    NARCIS (Netherlands)

    Loftis, A.D.

    2008-01-01

    Ehrlichia are obligate intracellular pathogens, transmitted by ixodid ticks, of both animals and humans. Ehrlichiae are emerging diseases in the USA, and the discovery of new species proceeds more rapidly than the development of models to study these agents. Laboratory animals were evaluated as

  20. Host Jumps and Radiation, Not Co‐Divergence Drives Diversification of Obligate Pathogens. A Case Study in Downy Mildews and Asteraceae

    Science.gov (United States)

    Choi, Young-Joon; Thines, Marco

    2015-01-01

    Even though the microevolution of plant hosts and pathogens has been intensely studied, knowledge regarding macro-evolutionary patterns is limited. Having the highest species diversity and host-specificity among Oomycetes, downy mildews are a useful a model for investigating long-term host-pathogen coevolution. We show that phylogenies of Bremia and Asteraceae are significantly congruent. The accepted hypothesis is that pathogens have diverged contemporarily with their hosts. But maximum clade age estimation and sequence divergence comparison reveal that congruence is not due to long-term coevolution but rather due to host-shift driven speciation (pseudo-cospeciation). This pattern results from parasite radiation in related hosts, long after radiation and speciation of the hosts. As large host shifts free pathogens from hosts with effector triggered immunity subsequent radiation and diversification in related hosts with similar innate immunity may follow, resulting in a pattern mimicking true co-divergence, which is probably limited to the terminal nodes in many pathogen groups. PMID:26230508

  1. The formation of lipid droplets favors intracellular Mycobacterium leprae survival in SW-10, non-myelinating Schwann cells

    OpenAIRE

    Jin, Song-Hyo; An, Sung-Kwan; Lee, Seong-Beom

    2017-01-01

    Leprosy is a chronic infectious disease that is caused by the obligate intracellular pathogen Mycobacterium leprae (M.leprae), which is the leading cause of all non-traumatic peripheral neuropathies worldwide. Although both myelinating and non-myelinating Schwann cells are infected by M.leprae in patients with lepromatous leprosy, M.leprae preferentially invades the non-myelinating Schwann cells. However, the effect of M.leprae infection on non-myelinating Schwann cells has not been elucidate...

  2. Transcriptome Analysis of the Intracellular Facultative Pathogen Piscirickettsia salmonis: Expression of Putative Groups of Genes Associated with Virulence and Iron Metabolism.

    Directory of Open Access Journals (Sweden)

    Alvaro Machuca

    Full Text Available The intracellular facultative bacteria Piscirickettsia salmonis is one of the most important pathogens of the Chilean aquaculture. However, there is a lack of information regarding the whole genomic transcriptional response according to different extracellular environments. We used next generation sequencing (NGS of RNA (RNA-seq to study the whole transcriptome of an isolate of P. salmonis (FAVET-INBIOGEN using a cell line culture and a modified cell-free liquid medium, with or without iron supplementation. This was done in order to obtain information about the factors there are involved in virulence and iron acquisition. First, the isolate was grown in the Sf21 cell line; then, the bacteria were cultured into a cell-free liquid medium supplemented or not with iron. We identified in the transcriptome, genes associated with type IV secretion systems, genes related to flagellar structure assembly, several proteases and sigma factors, and genes related to the development of drug resistance. Additionally, we identified for the first time several iron-metabolism associated genes including at least two iron uptake pathways (ferrous iron and ferric iron uptake that are actually expressed in the different conditions analyzed. We further describe putative genes that are related with the use and storage of iron in the bacteria, which have not been previously described. Several sets of genes related to virulence were expressed in both the cell line and cell-free culture media (for example those related to flagellar structure; such as basal body, MS-ring, C-ring, proximal and distal rod, and filament, which may play roles in other basic processes rather than been restricted to virulence.

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

    Science.gov (United States)

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

    2015-01-01

    Macroautophagy (autophagy) is an evolutionarily conserved catabolic process involved in physiological and developmental processes including cell survival, death, and innate immunity. Homologues of most of 36 originally discovered autophagy-related (ATG) genes in yeast have been characterized in higher eukaryotes including insects. In this study, the homologues of ATG3 (TmATG3) and ATG5 (TmATG5) were isolated from the coleopteran beetle, Tenebrio molitor by expressed sequence tag and RNAseq approaches. The cDNA of TmATG3 and TmATG5 comprise open-reading frame sizes of 963 and 792 bp encoding polypeptides of 320 and 263 amino acid residues, respectively. TmATG3 and TmATG5 mRNA are expressed in all developmental stages, and mainly in fat body and hemocytes of larvae. TmATG3 and TmATG5 showed an overall sequence identity of 58-95% to other insect Atg proteins. There exist clear one-to-one orthologs of TmATG3 and TmATG5 in Tribolium and that they clustered together in the gene tree. Depletion of TmATG3 and TmATG5 by RNA interference led to a significant reduction in survival ability of T. molitor larvae against an intracellular pathogen, Listeria monocytogenes. Six days post-Listeria challenge, the survival rate in the dsEGFP-injected (where EGFP is enhanced green fluorescent protein) control larvae was significantly higher (55%) compared to 4 and 3% for TmATG3 and TmATG5 double-stranded RNA injected larvae, respectively. These data suggested that TmATG3 and TmATG5 may play putative role in mediating autophagy-based clearance of Listeria in T. molitor model. © 2014 Wiley Periodicals, Inc.

  4. Biological macromolecules based targeted nanodrug delivery systems for the treatment of intracellular infections.

    Science.gov (United States)

    Aparna, V; Shiva, M; Biswas, Raja; Jayakumar, R

    2018-04-15

    Intracellular infections are tricky to treat, the reason being the poor penetration of antibiotics/antimycotics into the microbial niche (host cell). Macrophages are primary targets of facultative and obligate intracellular bacteria/fungi to be abused as host cells. The need for drugs with better intracellular penetration led to the development of endocytosable drug carriers, which can cross the cell membrane of the host cells (macrophages) by imitating the entry path of the pathogens. Therefore, the drugs can be targeted to macrophages ensuring enhanced therapeutic effect. This review discusses the exploitation of various nanocarriers for targeted delivery of drugs to the macrophages in the last two decades. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Mechanisms of cellular invasion by intracellular parasites.

    Science.gov (United States)

    Walker, Dawn M; Oghumu, Steve; Gupta, Gaurav; McGwire, Bradford S; Drew, Mark E; Satoskar, Abhay R

    2014-04-01

    Numerous disease-causing parasites must invade host cells in order to prosper. Collectively, such pathogens are responsible for a staggering amount of human sickness and death throughout the world. Leishmaniasis, Chagas disease, toxoplasmosis, and malaria are neglected diseases and therefore are linked to socio-economical and geographical factors, affecting well-over half the world's population. Such obligate intracellular parasites have co-evolved with humans to establish a complexity of specific molecular parasite-host cell interactions, forming the basis of the parasite's cellular tropism. They make use of such interactions to invade host cells as a means to migrate through various tissues, to evade the host immune system, and to undergo intracellular replication. These cellular migration and invasion events are absolutely essential for the completion of the lifecycles of these parasites and lead to their for disease pathogenesis. This review is an overview of the molecular mechanisms of protozoan parasite invasion of host cells and discussion of therapeutic strategies, which could be developed by targeting these invasion pathways. Specifically, we focus on four species of protozoan parasites Leishmania, Trypanosoma cruzi, Plasmodium, and Toxoplasma, which are responsible for significant morbidity and mortality.

  6. Tropism and pathogenicity of rickettsiae

    Directory of Open Access Journals (Sweden)

    Tsuneo eUchiyama

    2012-06-01

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

  7. NCI & Division Obligations

    Science.gov (United States)

    Displays obligations for grants, contracts, training fellowships, intramural research, and management and support, including the number of grant awards, funding amounts, and percent of the total NCI budget.

  8. The Animal Pathogen-Like Type III Secretion System is Required for the Intracellular Survival of Burkholderia mallei within J774.2 Macrophages

    Science.gov (United States)

    2006-03-30

    for B. mallei are horses, donkeys, and mules (solipeds), but other animals, including mice, hamsters, guinea pigs, monkeys , lions, and dogs, are...Spa/Prg and Shigella Ipa/Mxi/Spa TTS networks, are important for in vitro and in vivo survival of these pathogenic Burkholderia species (9–12, 14, 15

  9. Disease resistance in Atlantic salmon (Salmo salar: coinfection of the intracellular bacterial pathogen Piscirickettsia salmonis and the sea louse Caligus rogercresseyi.

    Directory of Open Access Journals (Sweden)

    Jean Paul Lhorente

    Full Text Available BACKGROUND: Naturally occurring coinfections of pathogens have been reported in salmonids, but their consequences on disease resistance are unclear. We hypothesized that 1 coinfection of Caligus rogercresseyi reduces the resistance of Atlantic salmon to Piscirickettsia salmonis; and 2 coinfection resistance is a heritable trait that does not correlate with resistance to a single infection. METHODOLOGY: In total, 1,634 pedigreed Atlantic salmon were exposed to a single infection (SI of P. salmonis (primary pathogen or coinfection with C. rogercresseyi (secondary pathogen. Low and high level of coinfection were evaluated (LC = 44 copepodites per fish; HC = 88 copepodites per fish. Survival and quantitative genetic analyses were performed to determine the resistance to the single infection and coinfections. MAIN FINDINGS: C. rogercresseyi significantly increased the mortality in fish infected with P. salmonis (SI mortality = 251/545; LC mortality = 544/544 and HC mortality = 545/545. Heritability estimates for resistance to P. salmonis were similar and of medium magnitude in all treatments (h2SI = 0.23 ± 0.07; h2LC = 0.17 ± 0.08; h2HC = 0.24 ± 0.07. A large and significant genetic correlation with regard to resistance was observed between coinfection treatments (rg LC-HC = 0.99 ± 0.01 but not between the single and coinfection treatments (rg SI-LC = -0.14 ± 0.33; rg SI-HC = 0.32 ± 0.34. CONCLUSIONS/SIGNIFICANCE: C. rogercresseyi, as a secondary pathogen, reduces the resistance of Atlantic salmon to the pathogen P. salmonis. Resistance to coinfection of Piscirickettsia salmonis and Caligus rogercresseyi in Atlantic salmon is a heritable trait. The absence of a genetic correlation between resistance to a single infection and resistance to coinfection indicates that different genes control these processes. Coinfection of different pathogens and resistance to coinfection needs to be considered in future

  10. Disease resistance in Atlantic salmon (Salmo salar): coinfection of the intracellular bacterial pathogen Piscirickettsia salmonis and the sea louse Caligus rogercresseyi.

    Science.gov (United States)

    Lhorente, Jean Paul; Gallardo, José A; Villanueva, Beatriz; Carabaño, María J; Neira, Roberto

    2014-01-01

    Naturally occurring coinfections of pathogens have been reported in salmonids, but their consequences on disease resistance are unclear. We hypothesized that 1) coinfection of Caligus rogercresseyi reduces the resistance of Atlantic salmon to Piscirickettsia salmonis; and 2) coinfection resistance is a heritable trait that does not correlate with resistance to a single infection. In total, 1,634 pedigreed Atlantic salmon were exposed to a single infection (SI) of P. salmonis (primary pathogen) or coinfection with C. rogercresseyi (secondary pathogen). Low and high level of coinfection were evaluated (LC = 44 copepodites per fish; HC = 88 copepodites per fish). Survival and quantitative genetic analyses were performed to determine the resistance to the single infection and coinfections. C. rogercresseyi significantly increased the mortality in fish infected with P. salmonis (SI mortality = 251/545; LC mortality = 544/544 and HC mortality = 545/545). Heritability estimates for resistance to P. salmonis were similar and of medium magnitude in all treatments (h2SI = 0.23 ± 0.07; h2LC = 0.17 ± 0.08; h2HC = 0.24 ± 0.07). A large and significant genetic correlation with regard to resistance was observed between coinfection treatments (rg LC-HC = 0.99 ± 0.01) but not between the single and coinfection treatments (rg SI-LC = -0.14 ± 0.33; rg SI-HC = 0.32 ± 0.34). C. rogercresseyi, as a secondary pathogen, reduces the resistance of Atlantic salmon to the pathogen P. salmonis. Resistance to coinfection of Piscirickettsia salmonis and Caligus rogercresseyi in Atlantic salmon is a heritable trait. The absence of a genetic correlation between resistance to a single infection and resistance to coinfection indicates that different genes control these processes. Coinfection of different pathogens and resistance to coinfection needs to be considered in future research on salmon farming, selective breeding and conservation.

  11. Offset drilling obligations

    International Nuclear Information System (INIS)

    Boyd, K.D.; Kalmakoff, J.J.

    1998-01-01

    A review of the 'offset well' clause found in freehold and Crown natural gas and petroleum leases was presented. The objective was to provide lessors and lessees with a clear understanding of the rights and obligations associated with offset wells. It was noted that offset well obligations vary according to the form of lease used, the type of offsetting well, the regulatory regime and the geophysical characteristics of the producing formation. Some suggestions were made as to how current versions of the offset well clause can be amended to overcome some of the problems encountered in applying the clause to an offset horizontal well that has been drilled on adjoining lands. Failure to resolve the new issues presented by horizontal drilling technology in terms of documentation, which records respective rights and obligations on the basis of generally accepted principles, will result in large numbers of conflicts and unnecessary litigation. 144 refs., 1 fig

  12. Slovenia and Kyoto Obligation

    International Nuclear Information System (INIS)

    Tirsek, A.; Jevsek, F.; Plavcak, V.-P.

    1998-01-01

    The paper gives the possibilities of emission reduction as an obligation from Kyoto Protocol. The Slovenia environmental and energy strategies are regulated to implement the agreement to reduce the emissions of greenhouse gases by 8% to the year 2012 as regard the basic year 1986 in energy, transportation, industrial and other sectors, especially focused on electric power sector. (author)

  13. Family Obligations in Denmark

    DEFF Research Database (Denmark)

    Koch-Nielsen, Inger

    How is the balance in obligations between the Family and the Danish Welfare State? Can we observe a trend to shift the responsibility back to the family? This booklet intends to sketch the legal framework around the division of responsibilities between the Family and the state and to analyse...... to what extent and where the unit of rights and obliagations is the individual and where it is the family or household....

  14. Caveolin-2 associates with intracellular chlamydial inclusions independently of caveolin-1

    Directory of Open Access Journals (Sweden)

    Norkin Leonard C

    2004-07-01

    Full Text Available Abstract Background Lipid raft domains form in plasma membranes of eukaryotic cells by the tight packing of glycosphingolipids and cholesterol. Caveolae are invaginated structures that form in lipid raft domains when the protein caveolin-1 is expressed. The Chlamydiaceae are obligate intracellular bacterial pathogens that replicate entirely within inclusions that develop from the phagocytic vacuoles in which they enter. We recently found that host cell caveolin-1 is associated with the intracellular vacuoles and inclusions of some chlamydial strains and species, and that entry of those strains depends on intact lipid raft domains. Caveolin-2 is another member of the caveolin family of proteins that is present in caveolae, but of unknown function. Methods We utilized a caveolin-1 negative/caveolin-2 positive FRT cell line and laser confocal immunofluorescence techniques to visualize the colocalization of caveolin-2 with the chlamydial inclusions. Results We show here that in infected HeLa cells, caveolin-2, as well as caveolin-1, colocalizes with inclusions of C. pneumoniae (Cp, C. caviae (GPIC, and C. trachomatis serovars E, F and K. In addition, caveolin-2 also associates with C. trachomatis serovars A, B and C, although caveolin-1 did not colocalize with these organisms. Moreover, caveolin-2 appears to be specifically, or indirectly, associated with the pathogens at the inclusion membranes. Using caveolin-1 deficient FRT cells, we show that although caveolin-2 normally is not transported out of the Golgi in the absence of caveolin-1, it nevertheless colocalizes with chlamydial inclusions in these cells. However, our results also show that caveolin-2 did not colocalize with UV-irradiated Chlamydia in FRT cells, suggesting that in these caveolin-1 negative cells, pathogen viability and very likely pathogen gene expression are necessary for the acquisition of caveolin-2 from the Golgi. Conclusion Caveolin-2 associates with the chlamydial

  15. UK ignores treaty obligations

    International Nuclear Information System (INIS)

    Roche, P.

    1995-01-01

    A detailed critique is offered of United Kingdom (UK) political policy with respect to the Non-Proliferation Treaty, an interim agreement valid while nuclear disarmament was supposed to occur, by a representative of Greenpeace, the anti-nuclear campaigning group. The author argues that the civil and military nuclear programmes are still firmly linked, and emphasises his opinions by quoting examples of how UK politicians have broken treaty obligations in order to pursue their own political, and in some cases financial, goals. It is argued that the treaty has failed to force nuclear countries to disarm because of its promoted civil nuclear power programmes. (U.K.)

  16. Collateralized debt obligations (CDOs

    Directory of Open Access Journals (Sweden)

    Dragosavac Miloš

    2012-01-01

    Full Text Available Collateralized debt obligations (CDOs were issued in 1987 by bankers at Drexel Burnham Lambert Inc. A decade later, CDOs became the leading power on the credit derivative markets, on which the value of derivative assets was derived from the value of other assets. However, unlike options and credit swamps, CDOs are not real, which means that they are constructed, and sometimes even the construction of their construction. CDOs were made to satisfy different types of investors, at one end, there is low-risk with low-income, and at the other, high-risk with high-income. By 2007, following the bubble burst on the US real estate market, losses on the CDO market started to expand. By 2008, the crisis on the CDO market turned into what we call today 'the global financial crisis.' CDOs are 'in the heart' of the crisis, and even wider. Our attempt is to reveal the mechanism of collateralized debt obligations (CDOs and the way in which CDOs expanded the negative effects of the present global financial crisis.

  17. Multi-omics Analysis Sheds Light on the Evolution and the Intracellular Lifestyle Strategies of Spotted Fever Group Rickettsia spp.

    Science.gov (United States)

    El Karkouri, Khalid; Kowalczewska, Malgorzata; Armstrong, Nicholas; Azza, Said; Fournier, Pierre-Edouard; Raoult, Didier

    2017-01-01

    Arthropod-borne Rickettsia species are obligate intracellular bacteria which are pathogenic for humans. Within this genus, Rickettsia slovaca and Rickettsia conorii cause frequent and potentially severe infections, whereas Rickettsia raoultii and Rickettsia massiliae cause rare and milder infections. All four species belong to spotted fever group (SFG) rickettsiae. However, R. slovaca and R. raoultii cause scalp eschar and neck lymphadenopathy (SENLAT) and are mainly associated with Dermacentor ticks, whereas the other two species cause Mediterranean spotted fever (MSF) and are mainly transmitted by Rhipicephalus ticks. To identify the potential genes and protein profiles and to understand the evolutionary processes that could, comprehensively, relate to the differences in virulence and pathogenicity observed between these four species, we compared their genomes and proteomes. The virulent and milder agents displayed divergent phylogenomic evolution in two major clades, whereas either SENLAT or MSF disease suggests a discrete convergent evolution of one virulent and one milder agent, despite their distant genetic relatedness. Moreover, the two virulent species underwent strong reductive genomic evolution and protein structural variations, as well as a probable loss of plasmid(s), compared to the two milder species. However, an abundance of mobilome genes was observed only in the less pathogenic species. After infecting Xenopus laevis cells, the virulent agents displayed less up-regulated than down-regulated proteins, as well as less number of identified core proteins. Furthermore, their similar and distinct protein profiles did not contain some genes (e.g., omp A/B and rick A) known to be related to rickettsial adhesion, motility and/or virulence, but may include other putative virulence-, antivirulence-, and/or disease-related proteins. The identified evolutionary forces herein may have a strong impact on intracellular expressions and strategies in these

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

    African Journals Online (AJOL)

    2010-09-13

    Sep 13, 2010 ... The aim of the present study is to determine the pathogenic and potentially ... Keywords: pathogenic bacteria; antibiotic resistance; carpets; mosques; Tripoli; Libya .... During the process of praying, a Muslim is obliged to go.

  19. EVIDENCE FOR THE MACROPHAGE INDUCING GENE IN MYCOBACTERIUM INTRACELLULARE

    Science.gov (United States)

    Background: The Mycobacterium avium Complex (MAC) includes the species M. avium (MA), M. intracellulare (MI), and possibly others. Organisms belonging to the MAC are phylogenetically closely related, opportunistic pathogens. The macrophage inducing gene (mig) is the only well-des...

  20. COXIELLA BURNETII PATHOGENICITY MOLECULAR BASIS

    Directory of Open Access Journals (Sweden)

    Yu. A. Panferova

    2016-01-01

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

  1. A de-novo-assembly-based Data Analysis Pipeline for Plant Obligate Parasite Metatranscriptomic Studies

    Directory of Open Access Journals (Sweden)

    Li Guo

    2016-07-01

    Full Text Available Current and emerging plant diseases caused by obligate parasitic microbes such as rusts, downy mildews, and powdery mildews threaten worldwide crop production and food safety. These obligate parasites are typically unculturable in the laboratory, posing technical challenges to characterize them at the genetic and genomic level. Here we have developed a data analysis pipeline integrating several bioinformatic software programs. This pipeline facilitates rapid gene discovery and expression analysis of a plant host and its obligate parasite simultaneously by next generation sequencing of mixed host and pathogen RNA (i.e. metatranscriptomics. We applied this pipeline to metatranscriptomic sequencing data of sweet basil (Ocimum basilicum and its obligate downy mildew parasite Peronospora belbahrii, both lacking a sequenced genome. Even with a single data point, we were able to identify both candidate host defense genes and pathogen virulence genes that are highly expressed during infection. This demonstrates the power of this pipeline for identifying genes important in host-pathogen interactions without prior genomic information for either the plant host or the obligate biotrophic pathogen. The simplicity of this pipeline makes it accessible to researchers with limited computational skills and applicable to metatranscriptomic data analysis in a wide range of plant-obligate-parasite systems.

  2. Obligation target for sustainable energy

    International Nuclear Information System (INIS)

    Lensink, S.M.; Hekkenberg, M.

    2012-01-01

    The Dutch Ministry of Economic Affairs, Agriculture and Innovation asked ECN several questions about the development of a supplier's obligation. These questions addressed the volume of the certificates market. The questions are worded as follows by ECN: What is a realistic level to be set for the obligation for sustainable energy or for renewable electricity (in percentage of delivered electricity or TWh/year)? How far into the future should these obligations minimally be set? Is it desirable to limit the certificate issuance time to for example the economic life of an installation? This memo addresses the questions, knowing that the entire policy development process will still take considerable time. At the time of publication of this memo, large uncertainties still existed about the eventual shaping of future policy. [nl

  3. High throughput sequencing and proteomics to identify immunogenic proteins of a new pathogen: the dirty genome approach.

    Science.gov (United States)

    Greub, Gilbert; Kebbi-Beghdadi, Carole; Bertelli, Claire; Collyn, François; Riederer, Beat M; Yersin, Camille; Croxatto, Antony; Raoult, Didier

    2009-12-23

    With the availability of new generation sequencing technologies, bacterial genome projects have undergone a major boost. Still, chromosome completion needs a costly and time-consuming gap closure, especially when containing highly repetitive elements. However, incomplete genome data may be sufficiently informative to derive the pursued information. For emerging pathogens, i.e. newly identified pathogens, lack of release of genome data during gap closure stage is clearly medically counterproductive. We thus investigated the feasibility of a dirty genome approach, i.e. the release of unfinished genome sequences to develop serological diagnostic tools. We showed that almost the whole genome sequence of the emerging pathogen Parachlamydia acanthamoebae was retrieved even with relatively short reads from Genome Sequencer 20 and Solexa. The bacterial proteome was analyzed to select immunogenic proteins, which were then expressed and used to elaborate the first steps of an ELISA. This work constitutes the proof of principle for a dirty genome approach, i.e. the use of unfinished genome sequences of pathogenic bacteria, coupled with proteomics to rapidly identify new immunogenic proteins useful to develop in the future specific diagnostic tests such as ELISA, immunohistochemistry and direct antigen detection. Although applied here to an emerging pathogen, this combined dirty genome sequencing/proteomic approach may be used for any pathogen for which better diagnostics are needed. These genome sequences may also be very useful to develop DNA based diagnostic tests. All these diagnostic tools will allow further evaluations of the pathogenic potential of this obligate intracellular bacterium.

  4. Cancer Moonshot Funding Obligations FY 2017

    Science.gov (United States)

    NCI reports Cancer Moonshot obligations by funding mechanism. See obligations for Moonshot grants, intramural research, and contracts, including the number of grant awards, funding amounts, and percentages by mechanism of the total Cancer Moonshot budget.

  5. Hi-Jack: a novel computational framework for pathway-based inference of host–pathogen interactions

    KAUST Repository

    Kleftogiannis, Dimitrios A.

    2015-03-09

    Motivation: Pathogens infect their host and hijack the host machinery to produce more progeny pathogens. Obligate intracellular pathogens, in particular, require resources of the host to replicate. Therefore, infections by these pathogens lead to alterations in the metabolism of the host, shifting in favor of pathogen protein production. Some computational identification of mechanisms of host-pathogen interactions have been proposed, but it seems the problem has yet to be approached from the metabolite-hijacking angle. Results: We propose a novel computational framework, Hi-Jack, for inferring pathway-based interactions between a host and a pathogen that relies on the idea of metabolite hijacking. Hi-Jack searches metabolic network data from hosts and pathogens, and identifies candidate reactions where hijacking occurs. A novel scoring function ranks candidate hijacked reactions and identifies pathways in the host that interact with pathways in the pathogen, as well as the associated frequent hijacked metabolites. We also describe host-pathogen interaction principles that can be used in the future for subsequent studies. Our case study on Mycobacterium tuberculosis (Mtb) revealed pathways in human-e.g. carbohydrate metabolism, lipids metabolism and pathways related to amino acids metabolism-that are likely to be hijacked by the pathogen. In addition, we report interesting potential pathway interconnections between human and Mtb such as linkage of human fatty acid biosynthesis with Mtb biosynthesis of unsaturated fatty acids, or linkage of human pentose phosphate pathway with lipopolysaccharide biosynthesis in Mtb. © The Author 2015. Published by Oxford University Press. All rights reserved.

  6. Prevention Obligations in International Environmental Law

    NARCIS (Netherlands)

    Plakokefalos, I.

    2013-01-01

    The paper seeks to examine the content and nature of prevention obligations in international environmental law. Despite their frequent reference to these obligations in practice and in the literature their exact content remains ill-defined. Similarly, the exact nature of these obligations has not

  7. Hijacking of host cellular functions by an intracellular parasite, the microsporidian Anncaliia algerae.

    Directory of Open Access Journals (Sweden)

    Johan Panek

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

  8. Material obligations: Forms and content

    International Nuclear Information System (INIS)

    Johnson, L.

    1998-01-01

    This paper includes a detailed legal framework of the IAEA safeguards agreements, namely basic articles of the IAEA Statute, Treaty and Supply Agreement obligations and basic documents concerning decisions and practices of the Board of Governors. It describes as well the initiation process of the negotiation of safeguards agreements, contents comparison and implementation of the safeguards agreements, protocols to safeguards agreements, subsidiary arrangements, amendments and renegotiation documents

  9. Chlamydia pneumoniae : studies on an emerging pathogen

    NARCIS (Netherlands)

    R.P.A.J. Verkooyen (Roel)

    1997-01-01

    textabstractThe Chlamydiae are characterized as bacteria because of the composition of their cell wall and their growth by binary division. However, they are obligate intracellular bacterial parasites of eukaryotic cells that have a unique replication cycle similar to Rickettsia. Chlamydial

  10. Multi-omics Analysis Sheds Light on the Evolution and the Intracellular Lifestyle Strategies of Spotted Fever Group Rickettsia spp.

    Directory of Open Access Journals (Sweden)

    Khalid El Karkouri

    2017-07-01

    Full Text Available Arthropod-borne Rickettsia species are obligate intracellular bacteria which are pathogenic for humans. Within this genus, Rickettsia slovaca and Rickettsia conorii cause frequent and potentially severe infections, whereas Rickettsia raoultii and Rickettsia massiliae cause rare and milder infections. All four species belong to spotted fever group (SFG rickettsiae. However, R. slovaca and R. raoultii cause scalp eschar and neck lymphadenopathy (SENLAT and are mainly associated with Dermacentor ticks, whereas the other two species cause Mediterranean spotted fever (MSF and are mainly transmitted by Rhipicephalus ticks. To identify the potential genes and protein profiles and to understand the evolutionary processes that could, comprehensively, relate to the differences in virulence and pathogenicity observed between these four species, we compared their genomes and proteomes. The virulent and milder agents displayed divergent phylogenomic evolution in two major clades, whereas either SENLAT or MSF disease suggests a discrete convergent evolution of one virulent and one milder agent, despite their distant genetic relatedness. Moreover, the two virulent species underwent strong reductive genomic evolution and protein structural variations, as well as a probable loss of plasmid(s, compared to the two milder species. However, an abundance of mobilome genes was observed only in the less pathogenic species. After infecting Xenopus laevis cells, the virulent agents displayed less up-regulated than down-regulated proteins, as well as less number of identified core proteins. Furthermore, their similar and distinct protein profiles did not contain some genes (e.g., ompA/B and rickA known to be related to rickettsial adhesion, motility and/or virulence, but may include other putative virulence-, antivirulence-, and/or disease-related proteins. The identified evolutionary forces herein may have a strong impact on intracellular expressions and strategies in

  11. Multi-omics Analysis Sheds Light on the Evolution and the Intracellular Lifestyle Strategies of Spotted Fever Group Rickettsia spp.

    Science.gov (United States)

    El Karkouri, Khalid; Kowalczewska, Malgorzata; Armstrong, Nicholas; Azza, Said; Fournier, Pierre-Edouard; Raoult, Didier

    2017-01-01

    Arthropod-borne Rickettsia species are obligate intracellular bacteria which are pathogenic for humans. Within this genus, Rickettsia slovaca and Rickettsia conorii cause frequent and potentially severe infections, whereas Rickettsia raoultii and Rickettsia massiliae cause rare and milder infections. All four species belong to spotted fever group (SFG) rickettsiae. However, R. slovaca and R. raoultii cause scalp eschar and neck lymphadenopathy (SENLAT) and are mainly associated with Dermacentor ticks, whereas the other two species cause Mediterranean spotted fever (MSF) and are mainly transmitted by Rhipicephalus ticks. To identify the potential genes and protein profiles and to understand the evolutionary processes that could, comprehensively, relate to the differences in virulence and pathogenicity observed between these four species, we compared their genomes and proteomes. The virulent and milder agents displayed divergent phylogenomic evolution in two major clades, whereas either SENLAT or MSF disease suggests a discrete convergent evolution of one virulent and one milder agent, despite their distant genetic relatedness. Moreover, the two virulent species underwent strong reductive genomic evolution and protein structural variations, as well as a probable loss of plasmid(s), compared to the two milder species. However, an abundance of mobilome genes was observed only in the less pathogenic species. After infecting Xenopus laevis cells, the virulent agents displayed less up-regulated than down-regulated proteins, as well as less number of identified core proteins. Furthermore, their similar and distinct protein profiles did not contain some genes (e.g., ompA/B and rickA) known to be related to rickettsial adhesion, motility and/or virulence, but may include other putative virulence-, antivirulence-, and/or disease-related proteins. The identified evolutionary forces herein may have a strong impact on intracellular expressions and strategies in these rickettsiae

  12. Antibiotic-resistant obligate anaerobes during exacerbations of cystic fibrosis patients.

    Science.gov (United States)

    Worlitzsch, D; Rintelen, C; Böhm, K; Wollschläger, B; Merkel, N; Borneff-Lipp, M; Döring, G

    2009-05-01

    Pseudomonas aeruginosa and Staphylococcus aureus are thought to cause the majority of lung infections in patients with cystic fibrosis (CF). However, other bacterial pathogens may contribute to the pathophysiology of lung disease. Here, obligate anaerobes were identified in a cross-sectional study, and cell numbers and antibiotic susceptibilities of facultative and obligate anaerobes from 114 sputum samples from nine children and 36 adults with CF were determined. Furthermore, in 12 CF patients, we investigated whether conventional intravenous antibiotic therapy, administered during acute exacerbations, would affect the numbers of obligate anaerobes. Fifteen genera of obligate anaerobes were identified in 91% of the CF patients. Cell numbers (mean: 2.2 x 10(7) +/- standard deviation 6.9 x 10(7) CFU/mL of sputum sample) were comparable to those of P. aeruginosa and S. aureus. Staphylococcus saccharolyticus and Peptostreptococcus prevotii were most prevalent. Infection with P. aeruginosa did not increase the likelihood that obligate anaerobes are present in sputum specimens. Single obligate anaerobic species persisted for up to 11 months in sputum plugs in vivo. Patients with and without obligate anaerobes in sputum specimens did not differ in lung function. Intravenous therapy directed against P. aeruginosa during acute exacerbations increased lung function, but did not reduce the numbers of obligate anaerobes. Obligate anaerobic species differed widely in their patterns of resistance against meropenem, piperacillin-tazobactam, clindamycin, metronidazole and ceftazidime. In 58% of patients with acute exacerbations, obligate anaerobes were detected that were resistant to the antibiotics used for treatment. Antibiotic therapy, optimized to target anaerobes in addition to P. aeruginosa, may improve the management of CF lung disease.

  13. The Essential Role of Cholesterol Metabolism in the Intracellular Survival of Mycobacterium leprae Is Not Coupled to Central Carbon Metabolism and Energy Production.

    Science.gov (United States)

    Marques, Maria Angela M; Berrêdo-Pinho, Marcia; Rosa, Thabatta L S A; Pujari, Venugopal; Lemes, Robertha M R; Lery, Leticia M S; Silva, Carlos Adriano M; Guimarães, Ana Carolina R; Atella, Georgia C; Wheat, William H; Brennan, Patrick J; Crick, Dean C; Belisle, John T; Pessolani, Maria Cristina V

    2015-12-01

    Mycobacterium leprae induces the formation of lipid droplets, which are recruited to pathogen-containing phagosomes in infected macrophages and Schwann cells. Cholesterol is among the lipids with increased abundance in M. leprae-infected cells, and intracellular survival relies on cholesterol accumulation. The present study investigated the capacity of M. leprae to acquire and metabolize cholesterol. In silico analyses showed that oxidation of cholesterol to cholest-4-en-3-one (cholestenone), the first step of cholesterol degradation catalyzed by the enzyme 3β-hydroxysteroid dehydrogenase (3β-HSD), is apparently the only portion of the cholesterol catabolic pathway seen in Mycobacterium tuberculosis preserved by M. leprae. Incubation of bacteria with radiolabeled cholesterol confirmed the in silico predictions. Radiorespirometry and lipid analyses performed after incubating M. leprae with [4-(14)C]cholesterol or [26-(14)C]cholesterol showed the inability of this pathogen to metabolize the sterol rings or the side chain of cholesterol as a source of energy and carbon. However, the bacteria avidly incorporated cholesterol and, as expected, converted it to cholestenone both in vitro and in vivo. Our data indicate that M. leprae has lost the capacity to degrade and utilize cholesterol as a nutritional source but retains the enzyme responsible for its oxidation to cholestenone. Thus, the essential role of cholesterol metabolism in the intracellular survival of M. leprae is uncoupled from central carbon metabolism and energy production. Further elucidation of cholesterol metabolism in the host cell during M. leprae infection will establish the mechanism by which this lipid supports M. leprae intracellular survival and will open new avenues for novel leprosy therapies. Our study focused on the obligate intracellular pathogen Mycobacterium leprae and its capacity to metabolize cholesterol. The data make an important contribution for those interested in understanding the

  14. Ancillary obligations as an additional obligation of a limited liability company's member

    Directory of Open Access Journals (Sweden)

    Marjanski Vladimir Ž.

    2016-01-01

    Full Text Available Ancillary obligation can be defined as an obligation of a limited liability company's member undertaken through the instrument of incorporation, which can take the form of monetary or non-monetary obligation (usually it is an obligation of a non-monetary character, which has a certain financial value and can be the object of a legally valid obligation. Ancillary obligations, as a contribution to activities of the company, are not regulated in the Law on Companies. The legal nature of this obligation is different from the obligation to make a contribution in money or in kind to a company's assets, to make additional pay-ins or from the landing of funds to the company. Ancillary obligation is an optional and additional obligation of a limited liability company's member and the obligation itself and its contents is defined in the instrument of incorporation. When a limited liability company's member undertakes an ancillary obligation this creates a distinctive relationship between the member and the company, concerning their respective obligations and the legal status of the company, as well as certain consequences derived from those obligations.

  15. Genetic transformation of an obligate anaerobe, P. gingivalis for FMN-green fluorescent protein expression in studying host-microbe interaction.

    Directory of Open Access Journals (Sweden)

    Chul Hee Choi

    Full Text Available The recent introduction of "oxygen-independent" flavin mononucleotide (FMN-based fluorescent proteins (FbFPs is of major interest to both eukaryotic and prokaryotic microbial biologists. Accordingly, we demonstrate for the first time that an obligate anaerobe, the successful opportunistic pathogen of the oral cavity, Porphyromonas gingivalis, can be genetically engineered for expression of the non-toxic green FbFP. The resulting transformants are functional for studying dynamic bacterial processes in living host cells. The visualization of the transformed P. gingivalis (PgFbFP revealed strong fluorescence that reached a maximum emission at 495 nm as determined by fluorescence microscopy and spectrofluorometry. Human primary gingival epithelial cells (GECs were infected with PgFbFP and the bacterial invasion of host cells was analyzed by a quantitative fluorescence microscopy and antibiotic protection assays. The results showed similar levels of intracellular bacteria for both wild type and PgFbFP strains. In conjunction with organelle specific fluorescent dyes, utilization of the transformed strain provided direct and accurate determination of the live/metabolically active P. gingivalis' trafficking in the GECs over time. Furthermore, the GECs were co-infected with PgFbFP and the ATP-dependent Clp serine protease-deficient mutant (ClpP- to study the differential fates of the two strains within the same host cells. Quantitative co-localization analyses displayed the intracellular PgFbFP significantly associated with the endoplasmic reticulum network, whereas the majority of ClpP- organisms trafficked into the lysosomes. Hence, we have developed a novel and reliable method to characterize live host cell-microbe interactions and demonstrated the adaptability of FMN-green fluorescent protein for studying persistent host infections induced by obligate anaerobic organisms.

  16. Genetic transformation of an obligate anaerobe, P. gingivalis for FMN-green fluorescent protein expression in studying host-microbe interaction.

    Science.gov (United States)

    Choi, Chul Hee; DeGuzman, Jefferson V; Lamont, Richard J; Yilmaz, Özlem

    2011-04-15

    The recent introduction of "oxygen-independent" flavin mononucleotide (FMN)-based fluorescent proteins (FbFPs) is of major interest to both eukaryotic and prokaryotic microbial biologists. Accordingly, we demonstrate for the first time that an obligate anaerobe, the successful opportunistic pathogen of the oral cavity, Porphyromonas gingivalis, can be genetically engineered for expression of the non-toxic green FbFP. The resulting transformants are functional for studying dynamic bacterial processes in living host cells. The visualization of the transformed P. gingivalis (PgFbFP) revealed strong fluorescence that reached a maximum emission at 495 nm as determined by fluorescence microscopy and spectrofluorometry. Human primary gingival epithelial cells (GECs) were infected with PgFbFP and the bacterial invasion of host cells was analyzed by a quantitative fluorescence microscopy and antibiotic protection assays. The results showed similar levels of intracellular bacteria for both wild type and PgFbFP strains. In conjunction with organelle specific fluorescent dyes, utilization of the transformed strain provided direct and accurate determination of the live/metabolically active P. gingivalis' trafficking in the GECs over time. Furthermore, the GECs were co-infected with PgFbFP and the ATP-dependent Clp serine protease-deficient mutant (ClpP-) to study the differential fates of the two strains within the same host cells. Quantitative co-localization analyses displayed the intracellular PgFbFP significantly associated with the endoplasmic reticulum network, whereas the majority of ClpP- organisms trafficked into the lysosomes. Hence, we have developed a novel and reliable method to characterize live host cell-microbe interactions and demonstrated the adaptability of FMN-green fluorescent protein for studying persistent host infections induced by obligate anaerobic organisms.

  17. Genomic Analysis of Pathogenicity Determinants in Mycobacterium kansasii Type I

    KAUST Repository

    Guan, Qingtian

    2016-01-01

    Mycobacteria, a genus within Actinobacteria Phylum, are well known for two pathogens that cause human diseases: leprosy and tuberculosis. Other than the obligate human mycobacteria, there is a group of bacteria that are present in the environment

  18. The Public Sector and Obligation to Contract

    DEFF Research Database (Denmark)

    Olesen, Karsten Naundrup; Indén, Tobias

    2016-01-01

    The paper concerns the situation where public sector bodies are forced to enter into contracts. These obligations to contract are analysed from two angles. First, the paper offers an analysis of the reasons for imposing such obligations to contract under Swedish and Danish law. Secondly the paper...... discusses some consequences of the public entities’ obligations to contract, more specific consequences for the use of rules that usually regulate contracts and the fact that obligations to contract imposed on public entities establish a new market and at the same time the obligations deprive the entities...... of the freedom to contract which is a fundamental to market behaviour. Finally attention is drawn to the fact that obligations to contract are also imposed on private entities. The paper takes Swedish and Danish regulations as a point of departure and provides an insight into regulations from these two countries...

  19. Ortholog-based screening and identification of genes related to intracellular survival.

    Science.gov (United States)

    Yang, Xiaowen; Wang, Jiawei; Bing, Guoxia; Bie, Pengfei; De, Yanyan; Lyu, Yanli; Wu, Qingmin

    2018-04-20

    Bioinformatics and comparative genomics analysis methods were used to predict unknown pathogen genes based on homology with identified or functionally clustered genes. In this study, the genes of common pathogens were analyzed to screen and identify genes associated with intracellular survival through sequence similarity, phylogenetic tree analysis and the λ-Red recombination system test method. The total 38,952 protein-coding genes of common pathogens were divided into 19,775 clusters. As demonstrated through a COG analysis, information storage and processing genes might play an important role intracellular survival. Only 19 clusters were present in facultative intracellular pathogens, and not all were present in extracellular pathogens. Construction of a phylogenetic tree selected 18 of these 19 clusters. Comparisons with the DEG database and previous research revealed that seven other clusters are considered essential gene clusters and that seven other clusters are associated with intracellular survival. Moreover, this study confirmed that clusters screened by orthologs with similar function could be replaced with an approved uvrY gene and its orthologs, and the results revealed that the usg gene is associated with intracellular survival. The study improves the current understanding of intracellular pathogens characteristics and allows further exploration of the intracellular survival-related gene modules in these pathogens. Copyright © 2018. Published by Elsevier B.V.

  20. On the obligation to obey the law

    Directory of Open Access Journals (Sweden)

    Zekavica Radomir G.

    2016-01-01

    Full Text Available The paper considers the question of a general obligation to obey the law. The author presents and analyzes the most significant views and arguments in support of the thesis that there is a general obligation to obey the law, as well as those understandings which are refuse this thesis. In concluding remarks the author presents a critical review of some key issues about general obligation to obey the law. In addition, the author outlines a hypothetical model of society and the legal system under which such an obligation is possible and has also asserted the basic assumptions and principles upon which it can be justified and reasonable. .

  1. Subversion of the cytoskeleton by intracellular bacteria: lessons from Listeria, Salmonella, and Vibrio

    Science.gov (United States)

    de Souza Santos, Marcela; Orth, Kim

    2018-01-01

    Summary Entry into host cells and intracellular persistence by invasive bacteria are tightly coupled to the ability of the bacterium to disrupt the eukaryotic cytoskeletal machinery. Herein we review the main strategies used by three intracellular pathogens to harness key modulators of the cytoskeleton. Two of these bacteria, namely Listeria monocytogenes and Salmonella enterica serovar Typhimurium, exhibit quite distinct intracellular lifestyles, and therefore, provide a comprehensive panel for the understanding of the intricate bacteria-cytoskeleton interplay during infections. The emerging intracellular pathogen Vibrio parahaemolyticus is depicted as a developing model for the uncovering of novel mechanisms used to hijack the cytoskeleton. PMID:25440316

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-02-25

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

  3. Constant Proportion Debt Obligations (CPDOs)

    DEFF Research Database (Denmark)

    Cont, Rama; Jessen, Cathrine

    2012-01-01

    be made arbitrarily small—and thus the credit rating arbitrarily high—by increasing leverage, but the ratings obtained strongly depend on assumptions on the credit environment (high spread or low spread). More importantly, CPDO loss distributions are found to exhibit a wide range of tail risk measures......Constant Proportion Debt Obligations (CPDOs) are structured credit derivatives that generate high coupon payments by dynamically leveraging a position in an underlying portfolio of investment-grade index default swaps. CPDO coupons and principal notes received high initial credit ratings from...... the major rating agencies, based on complex models for the joint transition of ratings and spreads for all names in the underlying portfolio. We propose a parsimonious model for analysing the performance of CPDO strategies using a top-down approach that captures the essential risk factors of the CPDO. Our...

  4. 45 CFR 2400.65 - Teaching obligation.

    Science.gov (United States)

    2010-10-01

    ... FOUNDATION FELLOWSHIP PROGRAM REQUIREMENTS Special Conditions § 2400.65 Teaching obligation. Upon receiving a Master's degree, each Fellow must teach American history, American government, social studies, or... 45 Public Welfare 4 2010-10-01 2010-10-01 false Teaching obligation. 2400.65 Section 2400.65...

  5. Effectiveness of qualitative and quantitative security obligations

    NARCIS (Netherlands)

    Pieters, Wolter; Padget, J.; Dechesne, F.; Dignum, V.; Aldewereld, H.

    Security policies in organisations typically take the form of obligations for the employees. However, it is often unclear what the purpose of such obligations is, and how these can be integrated in the operational processes of the organisation. This can result in policies that may be either too

  6. 47 CFR 27.1239 - Reimbursement obligation.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Reimbursement obligation. 27.1239 Section 27... Policies Governing the Transition of the 2500-2690 Mhz Band for Brs and Ebs § 27.1239 Reimbursement obligation. (a) A proponent may request reimbursement from BRS licensees and lessees, EBS lessees, and...

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

    Science.gov (United States)

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

    2008-12-09

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

  8. Overview of contractual obligations of the know-how licensor under the Macedonian Law of obligations

    Directory of Open Access Journals (Sweden)

    Nashkova Suzana

    2016-01-01

    Full Text Available The aim of this paper is to provide a comprehensive analysis of a part of contractual obligations of the licensor of know-how and their regulation in the Macedonian legislation. Special emphasis will be placed on two obligations that contracting parties inevitably incorporate into their agreement: the licensor's obligation to transfer the know-how and to give the necessary instructions and information for its successful utilization, and the licensor's obligation to guarantee the material and legal properties of know-how. Thus, this paper is divided into two systematic sections, focusing on each of these obligations respectively and examining the solutions contained in the Macedonian Obligation Relations Act that are applicable in the regulation of these contractual obligations.

  9. Microbial minimalism: genome reduction in bacterial pathogens.

    Science.gov (United States)

    Moran, Nancy A

    2002-03-08

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

  10. The economics of a landing obligation

    DEFF Research Database (Denmark)

    Andersen, Peder; Ståhl, Lisa

    By 2015 The European Common Fisheries Policy Reform includes a landing obligation in some fisheries and over the next few years all EU fisheries will be facing the obligation to land all catches. In spite of that, there is a lack of theoretical as well as empirical analyses of the consequences...... of a landing obligation. The paper includes an empirical analysis of the landing obligation’s impact on the Danish fishery in the short run. In the first part of the paper, we survey the fisheries economics literature for theoretical findings regarding behavioural aspects of a discard ban and we exploring gaps...... things, the analysis shows that the fisheries will suffer economic losses under the landing obligation if quotas are not increased with the historical discard rate. With quota top-ups however fisheries can experience economic gains which increase with reduced minimum sizes or by increasing selectivity....

  11. USAID Dollars Obligated and Dollars Spent

    Data.gov (United States)

    US Agency for International Development — Displays obligations and disbursements by operating unit (OU) and sector, beginning with Fiscal Years 2009. The data was pulled from USAID's financial accounting...

  12. Effectiveness of Nigeria's international obligations in curbing ...

    African Journals Online (AJOL)

    Effectiveness of Nigeria's international obligations in curbing domestic violence. ... Nnamdi Azikiwe University Journal of International Law and Jurisprudence ... This paper examines the issue of domestic violence in Nigeria to determine the ...

  13. 30 CFR 717.11 - General obligations.

    Science.gov (United States)

    2010-07-01

    ... construction, operation, and reclamation of shafts, adits, underground support facilities, underground mining... Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR INITIAL PROGRAM REGULATIONS UNDERGROUND MINING GENERAL PERFORMANCE STANDARDS § 717.11 General obligations. (a...

  14. Intracellular Bacterial Infections: A Challenge for Developing Cellular Mediated Immunity Vaccines for Farmed Fish

    Directory of Open Access Journals (Sweden)

    Hetron Mweemba Munang’andu

    2018-04-01

    Full Text Available Aquaculture is one of the most rapidly expanding farming systems in the world. Its rapid expansion has brought with it several pathogens infecting different fish species. As a result, there has been a corresponding expansion in vaccine development to cope with the increasing number of infectious diseases in aquaculture. The success of vaccine development for bacterial diseases in aquaculture is largely attributed to empirical vaccine designs based on inactivation of whole cell (WCI bacteria vaccines. However, an upcoming challenge in vaccine design is the increase of intracellular bacterial pathogens that are not responsive to WCI vaccines. Intracellular bacterial vaccines evoke cellular mediated immune (CMI responses that “kill” and eliminate infected cells, unlike WCI vaccines that induce humoral immune responses whose protective mechanism is neutralization of extracellular replicating pathogens by antibodies. In this synopsis, I provide an overview of the intracellular bacterial pathogens infecting different fish species in aquaculture, outlining their mechanisms of invasion, replication, and survival intracellularly based on existing data. I also bring into perspective the current state of CMI understanding in fish together with its potential application in vaccine development. Further, I highlight the immunological pitfalls that have derailed our ability to produce protective vaccines against intracellular pathogens for finfish. Overall, the synopsis put forth herein advocates for a shift in vaccine design to include CMI-based vaccines against intracellular pathogens currently adversely affecting the aquaculture industry.

  15. Host-microbe and microbe-microbe interactions in the evolution of obligate plant parasitism.

    Science.gov (United States)

    Kemen, Ariane C; Agler, Matthew T; Kemen, Eric

    2015-06-01

    Research on obligate biotrophic plant parasites, which reproduce only on living hosts, has revealed a broad diversity of filamentous microbes that have independently acquired complex morphological structures, such as haustoria. Genome studies have also demonstrated a concerted loss of genes for metabolism and lytic enzymes, and gain of diversity of genes coding for effectors involved in host defense suppression. So far, these traits converge in all known obligate biotrophic parasites, but unexpected genome plasticity remains. This plasticity is manifested as transposable element (TE)-driven increases in genome size, observed to be associated with the diversification of virulence genes under selection pressure. Genome expansion could result from the governing of the pathogen response to ecological selection pressures, such as host or nutrient availability, or to microbial interactions, such as competition, hyperparasitism and beneficial cooperations. Expansion is balanced by alternating sexual and asexual cycles, as well as selfing and outcrossing, which operate to control transposon activity in populations. In turn, the prevalence of these balancing mechanisms seems to be correlated with external biotic factors, suggesting a complex, interconnected evolutionary network in host-pathogen-microbe interactions. Therefore, the next phase of obligate biotrophic pathogen research will need to uncover how this network, including multitrophic interactions, shapes the evolution and diversity of pathogens. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

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

    Czech Academy of Sciences Publication Activity Database

    Woo, Y.H.; Ansari, H.; Otto, T.D.; Klinger, C.M.; Kolisko, M.; Michálek, Jan; Saxena, A.; Shanmugam, D.; Tayyrov, A.; Veluchamy, A.; Ali, S.; Bernal, A.; del Campo, J.; Cihlář, Jaromír; Flegontov, Pavel; Gornik, S.G.; Hajdušková, Eva; Horák, Aleš; Janouškovec, J.; Katris, N.J.; Mast, F.D.; Miranda-Saavedra, D.; Mourier, T.; Naeem, R.; Nair, M.; Panigrahi, A.K.; Rawlings, N.D.; Padron-Regalado, E.; Ramaprasad, A.; Samad, N.; Tomčala, Aleš; Wilkes, J.; Neafsey, D.E.; Doerig, C.; Bowler, C.; Keeling, P.J.; Roos, D.S.; Dacks, J.B.; Templeton, T.J.; Waller, R.F.; Lukeš, Julius; Oborník, Miroslav; Pain, A.

    2015-01-01

    Roč. 4, JUL 15 2015 (2015), e06974 ISSN 2050-084X R&D Projects: GA ČR GAP506/12/1522; GA ČR GBP501/12/G055; GA ČR GA13-33039S Institutional support: RVO:60077344 Keywords : multiple sequence alignment * dense granule proteins * hidden markov model Subject RIV: EE - Microbiology, Virology Impact factor: 8.282, year: 2015

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

    Czech Academy of Sciences Publication Activity Database

    Woo, Y.H.; Oborník, Miroslav

    2015-01-01

    Roč. 4, JUL 15 (2015) ISSN 2050-084X R&D Projects: GA ČR GBP501/12/G055 Institutional support: RVO:61388971 Keywords : MULTIPLE SEQUENCE ALIGNMENT * MULTIPLE SEQUENCE ALIGNMENT * HIDDEN MARKOV MODEL Subject RIV: EE - Microbiology, Virology Impact factor: 8.282, year: 2015

  18. High throughput sequencing and proteomics to identify immunogenic proteins of a new pathogen: the dirty genome approach.

    Directory of Open Access Journals (Sweden)

    Gilbert Greub

    Full Text Available BACKGROUND: With the availability of new generation sequencing technologies, bacterial genome projects have undergone a major boost. Still, chromosome completion needs a costly and time-consuming gap closure, especially when containing highly repetitive elements. However, incomplete genome data may be sufficiently informative to derive the pursued information. For emerging pathogens, i.e. newly identified pathogens, lack of release of genome data during gap closure stage is clearly medically counterproductive. METHODS/PRINCIPAL FINDINGS: We thus investigated the feasibility of a dirty genome approach, i.e. the release of unfinished genome sequences to develop serological diagnostic tools. We showed that almost the whole genome sequence of the emerging pathogen Parachlamydia acanthamoebae was retrieved even with relatively short reads from Genome Sequencer 20 and Solexa. The bacterial proteome was analyzed to select immunogenic proteins, which were then expressed and used to elaborate the first steps of an ELISA. CONCLUSIONS/SIGNIFICANCE: This work constitutes the proof of principle for a dirty genome approach, i.e. the use of unfinished genome sequences of pathogenic bacteria, coupled with proteomics to rapidly identify new immunogenic proteins useful to develop in the future specific diagnostic tests such as ELISA, immunohistochemistry and direct antigen detection. Although applied here to an emerging pathogen, this combined dirty genome sequencing/proteomic approach may be used for any pathogen for which better diagnostics are needed. These genome sequences may also be very useful to develop DNA based diagnostic tests. All these diagnostic tools will allow further evaluations of the pathogenic potential of this obligate intracellular bacterium.

  19. Exploring anti-bacterial compounds against intracellular Legionella.

    Directory of Open Access Journals (Sweden)

    Christopher F Harrison

    Full Text Available Legionella pneumophila is a ubiquitous fresh-water bacterium which reproduces within its erstwhile predators, environmental amoeba, by subverting the normal pathway of phagocytosis and degradation. The molecular mechanisms which confer resistance to amoeba are apparently conserved and also allow replication within macrophages. Thus, L. pneumophila can act as an 'accidental' human pathogen and cause a severe pneumonia known as Legionnaires' disease. The intracellular localisation of L. pneumophila protects it from some antibiotics, and this fact must be taken into account to develop new anti-bacterial compounds. In addition, the intracellular lifestyle of L. pneumophila may render the bacteria susceptible to compounds diminishing bacterial virulence and decreasing intracellular survival and replication of this pathogen. The development of a single infection cycle intracellular replication assay using GFP-producing L. pneumophila and Acanthamoebacastellanii amoeba is reported here. This fluorescence-based assay allows for continuous monitoring of intracellular replication rates, revealing the effect of bacterial gene deletions or drug treatment. To examine how perturbations of the host cell affect L. pneumophila replication, several known host-targeting compounds were tested, including modulators of cytoskeletal dynamics, vesicle scission and Ras GTPase localisation. Our results reveal a hitherto unrealized potential antibiotic property of the β-lactone-based Ras depalmitoylation inhibitor palmostatin M, but not the closely related inhibitor palmostatin B. Further characterisation indicated that this compound caused specific growth inhibition of Legionella and Mycobacterium species, suggesting that it may act on a common bacterial target.

  20. Exploring Anti-Bacterial Compounds against Intracellular Legionella

    Science.gov (United States)

    Harrison, Christopher F.; Kicka, Sébastien; Trofimov, Valentin; Berschl, Kathrin; Ouertatani-Sakouhi, Hajer; Ackermann, Nikolaus; Hedberg, Christian; Cosson, Pierre; Soldati, Thierry; Hilbi, Hubert

    2013-01-01

    Legionella pneumophila is a ubiquitous fresh-water bacterium which reproduces within its erstwhile predators, environmental amoeba, by subverting the normal pathway of phagocytosis and degradation. The molecular mechanisms which confer resistance to amoeba are apparently conserved and also allow replication within macrophages. Thus, L. pneumophila can act as an ‘accidental’ human pathogen and cause a severe pneumonia known as Legionnaires’ disease. The intracellular localisation of L. pneumophila protects it from some antibiotics, and this fact must be taken into account to develop new anti-bacterial compounds. In addition, the intracellular lifestyle of L. pneumophila may render the bacteria susceptible to compounds diminishing bacterial virulence and decreasing intracellular survival and replication of this pathogen. The development of a single infection cycle intracellular replication assay using GFP-producing L. pneumophila and Acanthamoeba castellanii amoeba is reported here. This fluorescence-based assay allows for continuous monitoring of intracellular replication rates, revealing the effect of bacterial gene deletions or drug treatment. To examine how perturbations of the host cell affect L. pneumophila replication, several known host-targeting compounds were tested, including modulators of cytoskeletal dynamics, vesicle scission and Ras GTPase localisation. Our results reveal a hitherto unrealized potential antibiotic property of the β-lactone-based Ras depalmitoylation inhibitor palmostatin M, but not the closely related inhibitor palmostatin B. Further characterisation indicated that this compound caused specific growth inhibition of Legionella and Mycobacterium species, suggesting that it may act on a common bacterial target. PMID:24058631

  1. Pathogenicity gene variations within the order Entomophthorales

    DEFF Research Database (Denmark)

    Grell, Morten Nedergaard; Jensen, Annette Bruun; Lange, Lene

    Fungi within the order Entomophthorales (subphylum Entomophthoromycotina) are obligate biotrophic pathogens of arthropods with a remarkable narrow host range. Infection takes place through the cuticle when conidia hit a susceptible host, facilitated by enzymatic and mechanical mechanisms. In the ...... pathogenicity genes within genera Entomophthora and Pandora, using fungal genomic DNA originating from field-collected, infected insect host species of dipteran (flies, mosquitoes) or hemipteran (aphid) origin.......Fungi within the order Entomophthorales (subphylum Entomophthoromycotina) are obligate biotrophic pathogens of arthropods with a remarkable narrow host range. Infection takes place through the cuticle when conidia hit a susceptible host, facilitated by enzymatic and mechanical mechanisms......, conidia are produced and discharged when humidity gets high—usually during night. In an earlier secretome study of field-collected grain aphids (Sitobion avenae) infected with entomophthoralean fungi, a number of pathogenesis-related, secreted enzymes were discovered (Fungal Genetics and Biology 2011, vol...

  2. Whistleblowing and the bioethicist's public obligations.

    Science.gov (United States)

    MacDougall, D Robert

    2014-10-01

    Bioethicists are sometimes thought to have heightened obligations by virtue of the fact that their professional role addresses ethics or morals. For this reason it has been argued that bioethicists ought to "whistleblow"--that is, publicly expose the wrongful or potentially harmful activities of their employer--more often than do other kinds of employees. This article argues that bioethicists do indeed have a heightened obligation to whistleblow, but not because bioethicists have heightened moral obligations in general. Rather, the special duties of bioethicists to act as whistleblowers are best understood by examining the nature of the ethical dilemma typically encountered by private employees and showing why bioethicists do not encounter this dilemma in the same way. Whistleblowing is usually understood as a moral dilemma involving conflicting duties to two parties: the public and a private employer. However, this article argues that this way of understanding whistleblowing has the implication that professions whose members identify their employer as the public-such as government employees or public servants--cannot consider whistleblowing a moral dilemma, because obligations are ultimately owed to only one party: the public. The article contends that bioethicists--even when privately employed--are similar to government employees in the sense that they do not have obligations to defer to the judgments of those with private interests. Consequently, bioethicists may be considered to have a special duty to whistleblow, although for different reasons than those usually cited.

  3. The obligation to contract in British law

    Directory of Open Access Journals (Sweden)

    Verena Klappstein

    2014-06-01

    Full Text Available Nowadays the obligation to contract is rarely looked upon. Without reason though, because it is neither outdated nor inoperable. Based on three common law doctrines the obligation to contract goes back to the Middle Ages. It has not lost its relevance, as it can still be found in modern statutory law, such as in the electricity and mail sector. What is more, it is a fundamental institution with a great impact. The analysis showed that the five chosen forms of obligations to contract bear analogical requirements but very similar rationales and economic consequences. It sets impaired market power right and it overstrikes irrational behaviour of market participants. As overall achievement it aligns the range of property, freedom of contract and freedom of competition.

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

    Science.gov (United States)

    Noore, Jabeen; Noore, Adly

    2013-01-01

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

  5. Chlamydia trachomatis co-opts GBF1 and CERT to acquire host sphingomyelin for distinct roles during intracellular development.

    Directory of Open Access Journals (Sweden)

    Cherilyn A Elwell

    2011-09-01

    Full Text Available The strain designated Chlamydia trachomatis serovar that was used for experiments in this paper is Chlamydia muridarum, a species closely related to C. trachomatis (and formerly termed the Mouse Pneumonitis strain of C. trachomatis. [corrected]. The obligate intracellular pathogen Chlamydia trachomatis replicates within a membrane-bound inclusion that acquires host sphingomyelin (SM, a process that is essential for replication as well as inclusion biogenesis. Previous studies demonstrate that SM is acquired by a Brefeldin A (BFA-sensitive vesicular trafficking pathway, although paradoxically, this pathway is dispensable for bacterial replication. This finding suggests that other lipid transport mechanisms are involved in the acquisition of host SM. In this work, we interrogated the role of specific components of BFA-sensitive and BFA-insensitive lipid trafficking pathways to define their contribution in SM acquisition during infection. We found that C. trachomatis hijacks components of both vesicular and non-vesicular lipid trafficking pathways for SM acquisition but that the SM obtained from these separate pathways is being utilized by the pathogen in different ways. We show that C. trachomatis selectively co-opts only one of the three known BFA targets, GBF1, a regulator of Arf1-dependent vesicular trafficking within the early secretory pathway for vesicle-mediated SM acquisition. The Arf1/GBF1-dependent pathway of SM acquisition is essential for inclusion membrane growth and stability but is not required for bacterial replication. In contrast, we show that C. trachomatis co-opts CERT, a lipid transfer protein that is a key component in non-vesicular ER to trans-Golgi trafficking of ceramide (the precursor for SM, for C. trachomatis replication. We demonstrate that C. trachomatis recruits CERT, its ER binding partner, VAP-A, and SM synthases, SMS1 and SMS2, to the inclusion and propose that these proteins establish an on-site SM biosynthetic

  6. Engineering a predatory bacterium as a proficient killer agent for intracellular bio-products recovery

    DEFF Research Database (Denmark)

    Martinez, Virginia; Herencias, Cristina; Jurkevitch, Edouard

    2016-01-01

    This work examines the potential of the predatory bacterium Bdellovibrio bacteriovorus HD100, an obligate predator of other Gram-negative bacteria, as an external cell-lytic agent for recovering valuable intracellular bio-products produced by prey cultures. The bio-product targets to be recovered......% of that accumulated by the prey bacteria, even at high biomass concentrations. This innovative downstream process highlights how B. bacteriovorus can be used as a novel, biological lytic agent for the inexpensive, industrial scale recovery of intracellular products from different Gram-negative prey cultures....

  7. Stochastic models of intracellular transport

    KAUST Repository

    Bressloff, Paul C.; Newby, Jay M.

    2013-01-01

    mechanisms for intracellular transport: passive diffusion and motor-driven active transport. Diffusive transport can be formulated in terms of the motion of an overdamped Brownian particle. On the other hand, active transport requires chemical energy, usually

  8. Inability and Obligation in Moral Judgment

    Science.gov (United States)

    Buckwalter, Wesley; Turri, John

    2015-01-01

    It is often thought that judgments about what we ought to do are limited by judgments about what we can do, or that “ought implies can.” We conducted eight experiments to test the link between a range of moral requirements and abilities in ordinary moral evaluations. Moral obligations were repeatedly attributed in tandem with inability, regardless of the type (Experiments 1–3), temporal duration (Experiment 5), or scope (Experiment 6) of inability. This pattern was consistently observed using a variety of moral vocabulary to probe moral judgments and was insensitive to different levels of seriousness for the consequences of inaction (Experiment 4). Judgments about moral obligation were no different for individuals who can or cannot perform physical actions, and these judgments differed from evaluations of a non-moral obligation (Experiment 7). Together these results demonstrate that commonsense morality rejects the “ought implies can” principle for moral requirements, and that judgments about moral obligation are made independently of considerations about ability. By contrast, judgments of blame were highly sensitive to considerations about ability (Experiment 8), which suggests that commonsense morality might accept a “blame implies can” principle. PMID:26296206

  9. Parental responses to child support obligations

    DEFF Research Database (Denmark)

    Rossin-Slater, Maya; Wüst, Miriam

    find that larger obligations are associated with higher new-partner fertility among both parents. The maternal fertility response is consistent with a positive income-fertility relationship, while the paternal fertility response may reflect increased demand for new offspring as a result of reduced...

  10. The social ascription of obligations to engineers

    NARCIS (Netherlands)

    Busby, J.S.; Coeckelbergh, Mark

    2003-01-01

    Discovering obligations that are ascribed to them by others is potentially an important element in the development of the moral imagination of engineers. Moral imagination cannot reasonably be developed by contemplating oneself and one’s task alone: there must be some element of discovering the

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

    Directory of Open Access Journals (Sweden)

    Jo-Ana eHerweg

    2015-06-01

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

  12. Singer's Utilitarian Account of Cosmopolitan Obligations: A Critical ...

    African Journals Online (AJOL)

    based conception of cosmopolitan obligations. Singer's thesis, simply put, is that from the perspective of utilitarian and cosmopolitan considerations, the affluent owe a moral obligation to provide aid to the masses of the poor irrespective of whether ...

  13. 5 CFR 2635.809 - Just financial obligations.

    Science.gov (United States)

    2010-01-01

    ... obligations. Employees shall satisfy in good faith their obligations as citizens, including all just financial... employee or reduced to judgment by a court. In good faith means an honest intention to fulfill any just...

  14. The Obligations of States towards Refugees under International Law

    DEFF Research Database (Denmark)

    Skordas, Achilles

    The main purpose of the current study is to discuss the obligations of States towards refugees under international law, and to argue that States have obligations towards refugees regardless of the ratification of the Geneva Convention....

  15. Insecticide resistance and intracellular proteases.

    Science.gov (United States)

    Wilkins, Richard M

    2017-12-01

    Pesticide resistance is an example of evolution in action with mechanisms of resistance arising from mutations or increased expression of intrinsic genes. Intracellular proteases have a key role in maintaining healthy cells and in responding to stressors such as pesticides. Insecticide-resistant insects have constitutively elevated intracellular protease activity compared to corresponding susceptible strains. This increase was shown for some cases originally through biochemical enzyme studies and subsequently putatively by transcriptomics and proteomics methods. Upregulation and expression of proteases have been characterised in resistant strains of some insect species, including mosquitoes. This increase in proteolysis results in more degradation products (amino acids) of intracellular proteins. These may be utilised in the resistant strain to better protect the cell from stress. There are changes in insect intracellular proteases shortly after insecticide exposure, suggesting a role in stress response. The use of protease and proteasome inhibitors or peptide mimetics as synergists with improved application techniques and through protease gene knockdown using RNA interference (possibly expressed in crop plants) may be potential pest management strategies, in situations where elevated intracellular proteases are relevant. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  16. Competition law and the obligation to supply

    DEFF Research Database (Denmark)

    Bergqvist, Christian

    2015-01-01

    While accepted in theory and practice that an obligation to supply, ser-vice or license can emerge under competition law, the scope of this is subject to many, if not lacunas, at least ambiguities, and no general ob-li¬gations of such nature can, no should, be identified. Further, and equally...... important, the narrow set of circumstances warranting inter-vention against refusals is defined by competition law in accordance with its underlying principles of a predominantly economic nature. Hence, competition law should not be relied upon as a corrective in-strument to lacunas in other areas of law, e.......g. compulsory licenses un-der IP law. Below, some considerations regarding the obligation to supply under competition law are offered for the purpose of correcting the misunderstandings....

  17. 29 CFR 500.100 - Vehicle safety obligations.

    Science.gov (United States)

    2010-07-01

    ... safety standards. Prima facie evidence that safety standards have been met will be shown by the presence... 29 Labor 3 2010-07-01 2010-07-01 false Vehicle safety obligations. 500.100 Section 500.100 Labor... § 500.100 Vehicle safety obligations. (a) General obligations. Each farm labor contractor, agricultural...

  18. Bystander Obligations at the Domestic and International Level Compared

    NARCIS (Netherlands)

    Spijkers, Otto|info:eu-repo/dai/nl/328454559

    2014-01-01

    This article examines whether States have a legal obligation to assist victims of serious breaches of fundamental obligations owed to the international community as a whole. This so-called ‘bystander State responsibility’ is compared with a similar legal obligation to assist victims at the domestic

  19. 12 CFR 208.101 - Obligations concerning institutional customers.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 2 2010-01-01 2010-01-01 false Obligations concerning institutional customers...) Interpretations § 208.101 Obligations concerning institutional customers. (a) As a result of broadened authority... on their suitability obligations when making recommendations to institutional customers. (b) The...

  20. 12 CFR 997.5 - Termination of the obligation.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Termination of the obligation. 997.5 Section 997.5 Banks and Banking FEDERAL HOUSING FINANCE BOARD NON-BANK SYSTEM ENTITIES RESOLUTION FUNDING CORPORATION OBLIGATIONS OF THE BANKS § 997.5 Termination of the obligation. (a) Generally. The Banks...

  1. 47 CFR 27.1184 - Triggering a reimbursement obligation.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Triggering a reimbursement obligation. 27.1184... reimbursement obligation. (a) The clearinghouse will apply the following test to determine when an AWS entity... paragraphs (a)(3)(i) and (ii) of this section, indicates that a reimbursement obligation exists, the...

  2. 47 CFR 27.1168 - Triggering a Reimbursement Obligation.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Triggering a Reimbursement Obligation. 27.1168... a Reimbursement Obligation. (a) The clearinghouse will apply the following test to determine when an... reimbursement obligation exists, the clearinghouse will calculate the reimbursement amount in accordance with...

  3. 47 CFR 24.247 - Triggering a reimbursement obligation.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Triggering a reimbursement obligation. 24.247... Mhz Band § 24.247 Triggering a reimbursement obligation. (a) Licensed PCS. The clearinghouse will... the Proximity Threshold test indicates that a reimbursement obligation exists, the clearinghouse will...

  4. 24 CFR 891.615 - Obligations of the family.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Obligations of the family. 891.615 Section 891.615 Housing and Urban Development Regulations Relating to Housing and Urban Development... 8 Assistance § 891.615 Obligations of the family. The obligations of the family are provided in...

  5. 24 CFR 891.755 - Obligations of the family.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Obligations of the family. 891.755... the Elderly and Persons with Disabilities Section 202 Projects for the Nonelderly Handicapped Families and Individuals-Section 162 Assistance § 891.755 Obligations of the family. The obligations of the...

  6. Constitutional obligations of a person and a citizen

    Directory of Open Access Journals (Sweden)

    Alexey Yu. Ogurtsov

    2011-01-01

    Full Text Available The constitution of the Russian Federation does not contain the list of obligations, but theoretically each legal right is supposed to correspond to a legal obligation. Such conformity is achieved by means of attaching obligations not only by Constitution, but by the branch legislation either.

  7. 7 CFR 400.167 - Limitations on Corporation's obligations.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Limitations on Corporation's obligations. 400.167... INSURANCE CORPORATION, DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE REGULATIONS Reinsurance Agreement... Corporation's obligations. The Agreement will include the following among the limitations on the obligations...

  8. 7 CFR 1724.71 - Borrower contractual obligations.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Borrower contractual obligations. 1724.71 Section... Contract Forms § 1724.71 Borrower contractual obligations. (a) Loan agreement. As a condition of a loan or... obligation is contained in section 5.16 of the loan contract. To comply with the provisions of the loan...

  9. 24 CFR 266.415 - Mortgage lien and other obligations.

    Science.gov (United States)

    2010-04-01

    ... determine, that all contractual obligations in connection with the mortgage transaction, including the... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Mortgage lien and other obligations... Mortgage and Closing Requirements; HUD Endorsement § 266.415 Mortgage lien and other obligations. (a) Liens...

  10. 7 CFR 1726.301 - Borrower contractual obligations.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Borrower contractual obligations. 1726.301 Section... Borrower contractual obligations. (a) Loan agreement. As a condition of a loan or loan guarantee under the... obligation is contained in section 5.16 of the loan contract. To comply with the provisions of the loan...

  11. Pathogen intelligence

    Directory of Open Access Journals (Sweden)

    Michael eSteinert

    2014-01-01

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

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

    Science.gov (United States)

    Lee, Stacey B

    2010-06-15

    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.

  13. Molecular genetic studies on obligate anaerobic bacteria

    International Nuclear Information System (INIS)

    Woods, D.R.

    1982-01-01

    Molecular genetic studies on obligate anaerobic bacteria have lagged behind similar studies in aerobes. However, the current interest in biotechnology, the involvement of anaerobes in disease and the emergence of antibioticresistant strains have focused attention on the genetics of anaerobes. This article reviews molecular genetic studies in Bacteroides spp., Clostridium spp. and methanogens. Certain genetic systems in some anaerobes differ from those in aerobes and illustrate the genetic diversity among bacteria

  14. Collateralised loan obligations (CLOs): A primer

    OpenAIRE

    Jobst, Andreas A.

    2002-01-01

    The following descriptive paper surveys the various types of loan securitisation and provides a working definition of so-called collateralised loan obligations (CLOs). Free of the common rhetoric and slogans, which sometimes substitute for understanding of the complex nature of structured finance, this paper describes the theoretical foundations of this specialised form of loan securitisation. Not only the distinctive properties of CLOs, but also the information economics inherent in the tran...

  15. ACCESSORIES OF FISCAL OBLIGATION. LEGAL REGIME

    Directory of Open Access Journals (Sweden)

    RADA POSTOLACHE

    2012-05-01

    Full Text Available The interest – which is an institution typical to private law, has been taken over by the fiscal field and adapted to the specific features of fiscal obligation – being defined by its imperative legal regime, which has at the least the following characteristic elements: unitary character, imposed legal percentage, compulsory demand of interest, automatic application. In order to render responsible fiscal debtors, the lawmaker has reintroduced, as an accessory of fiscal obligation, delayed payment penalties, which have a distinct nature and legal regime, but without the principle non bis in idem being transgressed. Our study aims to establish the legal regime ofaccessories typical to fiscal obligation, from the perspective of special normative acts, but also of the common law within the field – Civil Code and Government Ordinance No. 13/2011 – by pointing out at the same time both the particular circumstances and procedural ones regulated by the Fiscal Procedure Code, shedding light upon the controversial legal nature of accessories.

  16. Value, obligation and the asymmetry question.

    Science.gov (United States)

    Tooley, Michael

    1998-04-01

    Is there a prima facie obligation to produce additional individuals whose lives would be worth living? In his paper 'Is it good to make happy people?', Stuart Rachels argues not only that there is, but, also, that precisely as much weight should be assigned to the quality of life that would be enjoyed by such potential persons, if they were to be actualized, as to the quality of life enjoyed by actually existing persons. In response, I shall argue, first, that Rachels' view is exposed to very serious objections, and secondly, that his arguments in support of his position involve a crucial assumption, which cannot be sustained, concerning the relation between, on the one hand, propositions about good-making and bad-making properties, and, on the other, propositions about right-making and wrong-making ones. I shall then argue that there is a very plausible position concerning the conditions under which an action can be morally wrong which entails the following asymmetry: there is a prima facie obligation not to bring into existence individuals whose lives are not worth living, but there is no corresponding obligation to create additional individuals whose lives would be worth living.

  17. LOW PATHOGENIC POTENTIAL IN HETEROTROPHIC BACTERIA FROM POTABLE WATER

    Science.gov (United States)

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

  18. Fuel poverty and energy efficiency obligations – A critical assessment of the supplier obligation in the UK

    International Nuclear Information System (INIS)

    Rosenow, Jan; Platt, Reg; Flanagan, Brooke

    2013-01-01

    Energy efficiency obligations (or white certificates) are increasingly used to reduce carbon emissions. While the energy efficiency obligations were originally intended as carbon reduction and not fuel poverty policies, due to recognition of the potential for regressive outcomes they often include provisions for vulnerable and low-income customers. Intuitively, reducing carbon emissions and alleviating fuel poverty seem to be two sides of the same coin. There are, however, considerable tensions between the two when addressed through energy efficiency obligations, particularly arising from the potentially regressive impacts of rising energy prices resulting from such obligations, but also the complexity of targeting fuel poor households and the implications for deliverability. Despite those tensions, the UK government decided to use energy efficiency obligations, the supplier obligation, as the main policy for reducing fuel poverty. In light of the proposals, this paper provides an analysis of the main tensions between carbon reduction and fuel poverty alleviation within energy efficiency obligations, outlines the fuel poverty provisions of the British Supplier Obligation, assesses its rules for identifying the fuel poor, and provides a critical analysis of the planned policy changes. Based on this analysis, alternative approaches to targeting fuel poverty within future supplier obligations are proposed. - Highlights: • First comprehensive analysis of energy savings obligations and fuel poverty. • Systematic comparison of targeting efficiency of fuel poverty programmes. • Critical analysis of fuel poverty provisions in British supplier obligations. • Proposal of a new approach to targeting fuel poverty within energy savings obligations

  19. Subversion of inflammasome activation and pyroptosis by pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Larissa D Cunha

    2013-11-01

    Full Text Available Activation of the inflammasome occurs in response to a notably high number of pathogenic microbes and is a broad innate immune response that effectively contributes to restriction of pathogen replication and generation of adaptive immunity. Activation of these platforms leads to caspase-1- and/or caspase-11-dependent secretion of proteins, including cytokines, and induction of a specific form of cell death called pyroptosis, which directly or indirectly contribute for restriction of pathogen replication. Not surprisingly, bona fide intracellular pathogens developed strategies for manipulation of cell death to guarantee intracellular replication. In this sense, the remarkable advances in the knowledge of the inflammasome field have been accompanied by several reports characterizing the inhibition of this platform by several pathogenic bacteria. Herein, we review some processes used by pathogenic bacteria, including Yersinia spp., Pseudomonas aeruginosa, Vibrio parahaemolyticus, Chlamydia trachomatis, Francisella tularensis, Shigella flexneri, Legionella pneumophila and Coxiella burnetii to evade the activation of the inflammasome and the induction of pyroptosis.

  20. The formation of lipid droplets favors intracellular Mycobacterium leprae survival in SW-10, non-myelinating Schwann cells.

    Science.gov (United States)

    Jin, Song-Hyo; An, Sung-Kwan; Lee, Seong-Beom

    2017-06-01

    Leprosy is a chronic infectious disease that is caused by the obligate intracellular pathogen Mycobacterium leprae (M.leprae), which is the leading cause of all non-traumatic peripheral neuropathies worldwide. Although both myelinating and non-myelinating Schwann cells are infected by M.leprae in patients with lepromatous leprosy, M.leprae preferentially invades the non-myelinating Schwann cells. However, the effect of M.leprae infection on non-myelinating Schwann cells has not been elucidated. Lipid droplets (LDs) are found in M.leprae-infected Schwann cells in the nerve biopsies of lepromatous leprosy patients. M.leprae-induced LD formation favors intracellular M.leprae survival in primary Schwann cells and in a myelinating Schwann cell line referred to as ST88-14. In the current study, we initially characterized SW-10 cells and investigated the effects of LDs on M.leprae-infected SW-10 cells, which are non-myelinating Schwann cells. SW-10 cells express S100, a marker for cells from the neural crest, and NGFR p75, a marker for immature or non-myelinating Schwann cells. SW-10 cells, however, do not express myelin basic protein (MBP), a marker for myelinating Schwann cells, and myelin protein zero (MPZ), a marker for precursor, immature, or myelinating Schwann cells, all of which suggests that SW-10 cells are non-myelinating Schwann cells. In addition, SW-10 cells have phagocytic activity and can be infected with M. leprae. Infection with M. leprae induces the formation of LDs. Furthermore, inhibiting the formation of M. leprae-induced LD enhances the maturation of phagosomes containing live M.leprae and decreases the ATP content in the M. leprae found in SW-10 cells. These facts suggest that LD formation by M. leprae favors intracellular M. leprae survival in SW-10 cells, which leads to the logical conclusion that M.leprae-infected SW-10 cells can be a new model for investigating the interaction of M.leprae with non-myelinating Schwann cells.

  1. Interaction of pathogens with host cholesterol metabolism.

    Science.gov (United States)

    Sviridov, Dmitri; Bukrinsky, Michael

    2014-10-01

    Pathogens of different taxa, from prions to protozoa, target cellular cholesterol metabolism to advance their own development and to impair host immune responses, but also causing metabolic complications, for example, atherosclerosis. This review describes recent findings of how pathogens do it. A common theme in interaction between pathogens and host cholesterol metabolism is pathogens targeting lipid rafts of the host plasma membrane. Many intracellular pathogens use rafts as an entry gate, taking advantage of the endocytic machinery and high abundance of outward-looking molecules that can be used as receptors. At the same time, disruption of the rafts' functional capacity, achieved by the pathogens through a number of various means, impairs the ability of the host to generate immune response, thus helping pathogen to thrive. Pathogens cannot synthesize cholesterol, and salvaging host cholesterol helps pathogens build advanced cholesterol-containing membranes and assembly platforms. Impact on cholesterol metabolism is not limited to the infected cells; proteins and microRNAs secreted by infected cells affect lipid metabolism systemically. Given an essential role that host cholesterol metabolism plays in pathogen development, targeting this interaction may be a viable strategy to fight infections, as well as metabolic complications of the infections.

  2. Community ecology of fungal pathogens on Bromus tectorum [Chapter 7

    Science.gov (United States)

    Susan E. Meyer; Julie Beckstead; JanaLynn Pearce

    2016-01-01

    Bromus tectorum L. (cheatgrass or downy brome) presents a rich resource for soil microorganisms because of its abundant production of biomass, seeds, and surface litter. Many of these organisms are opportunistic saprophytes, but several fungal species regularly found in B. tectorum stands function as facultative or obligate pathogens. These organisms interact...

  3. Nutrient acquisition and secondary metabolites in plant pathogenic fungi

    DEFF Research Database (Denmark)

    Droce, Aida

    Fusarium graminearum is a necrotrophic plant pathogen that leads to severe infections of cereals contaminating them with mycotoxins harmful to human and animal. Blumeria graminis f. sp. hordei is an obligate biotroph that causes powdery mildew infections of barley. In this thesis, lifecycles and ...

  4. Antibody- and TRIM21-dependent intracellular restriction of Salmonella enterica.

    Science.gov (United States)

    Rakebrandt, Nikolas; Lentes, Sabine; Neumann, Heinz; James, Leo C; Neumann-Staubitz, Petra

    2014-11-01

    TRIM21 ('tripartite motif-containing protein 21', Ro52) is a ubiquitously expressed cytosolic Fc receptor, which has a potent role in protective immunity against nonenveloped viruses. TRIM21 mediates intracellular neutralisation of antibody-coated viruses, a process called ADIN (antibody-dependent intracellular neutralisation). Our results reveal a similar mechanism to fight bacterial infections. TRIM21 is recruited to the intracellular pathogen Salmonella enterica in epithelial cells early in infection. TRIM21 does not bind directly to S. enterica, but to antibodies opsonising it. Most importantly, bacterial restriction is dependent on TRIM21 as well as on the opsonisation state of the bacteria. Finally, Salmonella and TRIM21 colocalise with the autophagosomal marker LC3, and intracellular defence is enhanced in starved cells suggesting an involvement of the autophagocytic pathway. Our data extend the protective role of TRIM21 from viruses to bacteria and thereby strengthening the general role of ADIN in cellular immunity. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  5. STATE OBLIGATION ON VIRUS SAMPLE SHARING;FROM COMMON HERITAGE OF MANKIND TO STATE’S SOVEREIGN RIGHT

    Directory of Open Access Journals (Sweden)

    Nurul Barizah

    2015-06-01

    Full Text Available The tradition of free international exchange of viruses have been developed by the World Health Organization (WHO probably based on the principle of “Common Heritage of Mankind”.  This tradition lead to legal uncertainty and unfairness in the movement of resources among states and provides an opportunity for developed countries to obtain easy access to viruses of developing countries. Then, International Law has introduced a new regime of “State’s Sovereign Right.” This research focuses on whether Member States have an obligation to share pathogen materials, including viruses for preventing global public health emergency, and whether WHO Collaborating Centers has a right to  share viruses to private sectors. It examines the reason why States should apply that principle. This research is normative legal research by using conceptual approach and  statute approach. This research finds that viruses are part of genetic resources under the meaning of CBD Convention. Accordingly, there is no state obligation under International Law to share it. However, if there is an international human rights obligation to share virus, there should also be an international human rights obligation to assure the access of affordability of drugs and vaccines. Thus, each state will have an equal obligation to enhance the global public health.Key Words : Intellectual Property, Virus Sample Sharing, Common Heritage of Mankind, and State’s Sovereign Right

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

    Science.gov (United States)

    Manske, Christian; Hilbi, Hubert

    2014-01-01

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

  7. Detection and quantification of intracellular bacterial colonies by automated, high-throughput microscopy.

    Science.gov (United States)

    Ernstsen, Christina L; Login, Frédéric H; Jensen, Helene H; Nørregaard, Rikke; Møller-Jensen, Jakob; Nejsum, Lene N

    2017-08-01

    To target bacterial pathogens that invade and proliferate inside host cells, it is necessary to design intervention strategies directed against bacterial attachment, cellular invasion and intracellular proliferation. We present an automated microscopy-based, fast, high-throughput method for analyzing size and number of intracellular bacterial colonies in infected tissue culture cells. Cells are seeded in 48-well plates and infected with a GFP-expressing bacterial pathogen. Following gentamicin treatment to remove extracellular pathogens, cells are fixed and cell nuclei stained. This is followed by automated microscopy and subsequent semi-automated spot detection to determine the number of intracellular bacterial colonies, their size distribution, and the average number per host cell. Multiple 48-well plates can be processed sequentially and the procedure can be completed in one working day. As a model we quantified intracellular bacterial colonies formed by uropathogenic Escherichia coli (UPEC) during infection of human kidney cells (HKC-8). Urinary tract infections caused by UPEC are among the most common bacterial infectious diseases in humans. UPEC can colonize tissues of the urinary tract and is responsible for acute, chronic, and recurrent infections. In the bladder, UPEC can form intracellular quiescent reservoirs, thought to be responsible for recurrent infections. In the kidney, UPEC can colonize renal epithelial cells and pass to the blood stream, either via epithelial cell disruption or transcellular passage, to cause sepsis. Intracellular colonies are known to be clonal, originating from single invading UPEC. In our experimental setup, we found UPEC CFT073 intracellular bacterial colonies to be heterogeneous in size and present in nearly one third of the HKC-8 cells. This high-throughput experimental format substantially reduces experimental time and enables fast screening of the intracellular bacterial load and cellular distribution of multiple

  8. Stochastic models of intracellular transport

    KAUST Repository

    Bressloff, Paul C.

    2013-01-09

    The interior of a living cell is a crowded, heterogenuous, fluctuating environment. Hence, a major challenge in modeling intracellular transport is to analyze stochastic processes within complex environments. Broadly speaking, there are two basic mechanisms for intracellular transport: passive diffusion and motor-driven active transport. Diffusive transport can be formulated in terms of the motion of an overdamped Brownian particle. On the other hand, active transport requires chemical energy, usually in the form of adenosine triphosphate hydrolysis, and can be direction specific, allowing biomolecules to be transported long distances; this is particularly important in neurons due to their complex geometry. In this review a wide range of analytical methods and models of intracellular transport is presented. In the case of diffusive transport, narrow escape problems, diffusion to a small target, confined and single-file diffusion, homogenization theory, and fractional diffusion are considered. In the case of active transport, Brownian ratchets, random walk models, exclusion processes, random intermittent search processes, quasi-steady-state reduction methods, and mean-field approximations are considered. Applications include receptor trafficking, axonal transport, membrane diffusion, nuclear transport, protein-DNA interactions, virus trafficking, and the self-organization of subcellular structures. © 2013 American Physical Society.

  9. Iron in intracellular infection: to provide or to deprive?

    Directory of Open Access Journals (Sweden)

    Sandro eSilva-Gomes

    2013-12-01

    Full Text Available Due to their chemical versatility, transition metals were incorporated as cofactors for several basic metabolic pathways in living organisms. This same characteristic makes them potentially harmful, since they can be engaged in deleterious reactions like Fenton chemistry. As such, organisms have evolved highly specialized mechanisms to supply their own metal needs while keeping their toxic potential in check.This dual character comes into play in host-pathogen interactions, given that the host can either deprive the pathogen of these key nutrients or exploit them to induce toxicity towards the invading agent. Iron stands as the prototypic example of how a metal can be used to limit the growth of pathogens by nutrient deprivation, a mechanism widely studied in Mycobacterium infections. However, the host can also take advantage of iron-induced toxicity to control pathogen proliferation, as observed in infections caused by Leishmania. Whether we may harness either of the two pathways for therapeutical purposes is still ill-defined.In this review, we discuss how modulation of the host iron availability impacts the course of infections, focusing on those caused by two relevant intracellular pathogens, Mycobacterium and Leishmania.

  10. Is there a moral obligation not to infect others?

    Science.gov (United States)

    Harris, J; Holm, S

    1995-11-04

    The emergence of HIV infection and AIDS has refocused concern on the obligations surrounding the carrying and transmission of communicable diseases. This article asks three related questions: Is there a general duty not to spread contagion? Are there special obligations not to communicate disease in the workplace? And does the mode of transmission of the disease affect the ethics of transmission and, if so, how and to what extent? There seems to be a strong prima facie obligation not to harm others by making them ill where this is avoidable, and this obligation not to communicate disease applies as much to relatively trivial diseases like the common cold as it does to HIV disease. The reasonableness of expecting people to live up to this obligation, however, depends on society reciprocating the obligation in the form of providing protection and compensation.

  11. Revising Sangiovanni's reciprocity-based internationalism: towards international egalitarian obligations

    Directory of Open Access Journals (Sweden)

    Conor Heaney

    2016-06-01

    Full Text Available To whom do we owe obligations of socio-economic justice? How are such obligations generated? Internationalism denotes a range of approaches to these questions. This paper examines Andrea Sangiovanni's—an internationalist—response to these questions. Sangiovanni argues that we owe egalitarian obligations only to those in the state, and that egalitarian obligations are generated through relationships of ‘reciprocity’. His is a ‘reciprocity-based internationalism’ (RBI. RBI has two components—one normative and another empirical. In this paper, I will assume the normative component, but reject its empirical component. My rejection of the empirical component has normative implications for RBI, which generate egalitarian obligations beyond the state. In other words, my revision of RBI is an argument in favour of international egalitarian obligations not generated through cosmopolitanism, but through internationalism.

  12. Is there a moral obligation not to infect others?

    Science.gov (United States)

    Harris, J.; Holm, S.

    1995-01-01

    The emergence of HIV infection and AIDS has refocused concern on the obligations surrounding the carrying and transmission of communicable diseases. This article asks three related questions: Is there a general duty not to spread contagion? Are there special obligations not to communicate disease in the workplace? And does the mode of transmission of the disease affect the ethics of transmission and, if so, how and to what extent? There seems to be a strong prima facie obligation not to harm others by making them ill where this is avoidable, and this obligation not to communicate disease applies as much to relatively trivial diseases like the common cold as it does to HIV disease. The reasonableness of expecting people to live up to this obligation, however, depends on society reciprocating the obligation in the form of providing protection and compensation. Images p1216-a p1216-b p1217-a PMID:7488907

  13. Characterization of Leptin Intracellular Trafficking

    Directory of Open Access Journals (Sweden)

    E Walum

    2009-12-01

    Full Text Available Leptin is produced by adipose tissue, and its concentration in plasma is related to the amount of fat in the body. The leptin receptor (OBR is a member of the class I cytokine receptor family and several different isoforms, produced by alternative mRNA splicing are found in many tissues, including the hypothalamus. The two predominant isoforms includes a long form (OBRl with an intracellular domain of 303 amino acids and a shorter form (OBRs with an intracellular domain of 34 amino acids. Since OBRl is mainly expressed in the hypotalamus, it has been suggested to be the main signalling form. The peripheral production of leptin by adipocyte tissue and its effects as a signal of satiety in the central nervous system imply that leptin gains access to regions of the brain regulating in energy balance by crossing the blood-brain barrier. In an attempt to characterize the intracellular transport of leptin, we have followed binding internalization and degradation of leptin in HEK293 cells. We have also monitored the intracellular transport pathway of fluorescent conjugated leptin in HEK293 cells. Phenylarsine oxide, a general inhibitor of endocytosis, as well as incubation at mild hypertonic conditions, prevented the uptake of leptin, confirming a receptor-mediated internalization process. When internalized, 125I-leptin was rapidly accumulated inside the cells and reached a maximum after 10 min. After 70 minutes about 40-50% of total counts in each time point were found in the medium as TCA-soluble material. Leptin sorting, at the level of early endosomes, did not seem to involve recycling endosomes, since FITC-leptin was sorted from Cy3- transferrin containing compartments at 37°C. At 45 minutes of continuos internalization, FITC-leptin appeared mainly accumulated in late endocytic structures colocalizing with internalized rhodamine coupled epidermial growth factor (EGF and the lysosomal marker protein lamp-1. The transport of leptin was also shown

  14. The Role of Pathogenic Autoantibodies in Autoimmunity

    Directory of Open Access Journals (Sweden)

    Merrill J. Rowley

    2015-11-01

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

  15. Is there a moral obligation not to infect others?

    OpenAIRE

    Harris, J.; Holm, S.

    1995-01-01

    The emergence of HIV infection and AIDS has refocused concern on the obligations surrounding the carrying and transmission of communicable diseases. This article asks three related questions: Is there a general duty not to spread contagion? Are there special obligations not to communicate disease in the workplace? And does the mode of transmission of the disease affect the ethics of transmission and, if so, how and to what extent? There seems to be a strong prima facie obligation not to harm ...

  16. In the Nick of Time: Proactive Prevention of Obligation Violations

    DEFF Research Database (Denmark)

    Basin, David; Debois, Søren; Hildebrandt, Thomas

    2016-01-01

    We present a system model, an enforcement mechanism, and a policy language for the proactive enforcement of timed provisions and obligations. Our approach improves upon existing formalisms in two ways: (1) we exploit the target system's existing functionality to avert policy violations proactively...... declaratively express timed provisions and obligations as causal relationships between events, and DCR states explicitly represent pending obligations. As key technical results, we show that enforceability of DCR policies is decidable, we give a sufficient polynomial time verifiable condition for a policy...... to be enforceable, and we give an algorithm for determining from a DCR state a sequence of actions that discharge impending obligations....

  17. Foodborne pathogens

    Directory of Open Access Journals (Sweden)

    Thomas Bintsis

    2017-06-01

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

  18. Facultative or obligate anaerobic bacteria have the potential for multimodality therapy of solid tumours.

    Science.gov (United States)

    Wei, Ming Q; Ellem, Kay A O; Dunn, Paul; West, Malcolm J; Bai, Chun Xue; Vogelstein, Bert

    2007-02-01

    Recent understanding of the unique pathology of solid tumours has shed light on the difficult and disappointing nature of their clinical treatment. All solid tumours undergo angiogenesis that results in biological changes and adaptive metabolisms, i.e. formation of defective vessels, appearance of hypoxic areas, and emergence of an heterogeneous tumour cell population. This micro-milieu provides a haven for anaerobic bacteria. The strictly anaerobic clostridia have several advantages over other facultative anaerobes such as salmonella or lactic acid-producing, Gram-positive, obligate, anaerobic bifidobacteria. Both pathogenic and non-pathogenic clostridia have been demonstrated to specifically colonise and destroy solid tumours. Early trials of non-pathogenic strains in humans had shown plausible safety. Genetic modifications and adaptation of pathogenic and non-pathogenic strains have further created improved features. However, these manipulations rarely generate strains that resulted in complete tumour control alone. Combined modalities of therapies with chemo and radiation therapies, on the other hand, often perform better, including 'cure' of solid tumours in a high percentage of animals. Considering that clostridia have unlimited capacities for genetic improvement, we predict that designer clostridia forecast a promising future for the development of potent strains for tumour destruction, incorporating mechanisms such as immunotherapy to overcome immune suppression and to elicit strong anti-tumour responses.

  19. On A Recent Theory of 'Legal Obligation'

    Directory of Open Access Journals (Sweden)

    Bruno Leoni

    2009-02-01

    Full Text Available This paper, by the late Bruno Leoni, was originally published in the Italian journal Il Politico in 1966. In the article, Leoni reviews H.L.A. Hart’s The Concept of Law (1961. Hart first analyzes the concept of law by resorting to the classical concept of “obligation.” But he later tries a “fresh start” by resorting to the concept of “secondary rules.” In his review, Leoni argues that the former attempt is confronted with serious difficulties, and that the latter attempt (to which professor Hart possibly resorts in view of overcoming some of said difficulties is ultimately inconsistent with the former

  20. Modernizing international maintenance obligations in Serbia

    Directory of Open Access Journals (Sweden)

    Bordaš Bernadet

    2013-01-01

    Full Text Available The paper deals with the modernization of private international law of maintenance in Serbia in the light of the two newest international instruments drawn up by the Hague Conference on Private International Law. As Serbia has ratified the Hague Protocol on the Law Applicable to Maintenance Obligations in January 2013 introducing modern rules to the legal system of Serbia, the issue of ratification of the Hague Convention on the International Recovery of Child Support and Other Forms of Family Maintenance has arisen, in order to modernize this aspect of the international maintenance as well. In order to establish a position on the issue, the paper presents and analyzes the essential provisions of the Convention (scope of application, administrative cooperation, recognition and enforcement of decisions, stricto sensu enforcement. Based on the analyses, the concluding remarks offers some elements on the bases of which the competent authorities could form an opinion on the necessity and desirability of the ratification of the Convention.

  1. Utilities' ''obligation to serve'' under deregulation

    International Nuclear Information System (INIS)

    Alexander, C.B.

    1997-01-01

    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

  2. [Facultative and obligate aerobic methylobacteria synthesize cytokinins].

    Science.gov (United States)

    Ivanova, E G; Doronina, N V; Shepeliakovskaia, A O; Laman, A G; Brovko, F A; Trotsenko, Iu A

    2000-01-01

    The presence and expression of genes controlling the synthesis and secretion of cytokinins by the pink-pigmented facultative methylotroph Methylobacterium mesophilicum VKM B-2143 with the serine pathway and nonpigmented obligate methylotroph Methylovorus mays VKM B-2221 with the ribulose monophosphate pathway of C1 metabolism were shown using the polymerase chain reaction (PCR) and reverse transcription-PCR methods. The presence of the corresponding mRNA in M. mesophilicum cells grown on methanol or succinate suggests that the expression of these genes is constitutive. The cytokinin activity of culture liquid and its fractions was determined by a biotest with Amarantus caudatus L. seedlings. Using enzyme-linked immunosorbent analysis, we detected zeatin (riboside) in the culture liquid of both bacteria studied. The data obtained show that the aerobic methylobacteria are phytosymbionts that are able to utilize the single- and polycarbon compounds secreted by symbiotic plants and to synthesize cytokinins.

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

    Science.gov (United States)

    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 ΔcypAB mutant displayed increased sensitivity to environmental stressors, such as oxidative stress, pH, and detergents. In addition, the B. abortus ΔcypAB mutant strain had a reduced growth rate at lower temperature, a phenotype associated with defective expression of cyclophilins in other microorganisms. The B. abortus ΔcypAB 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

  4. Detection and quantification of intracellular bacterial colonies by automated, high-throughput microscopy

    DEFF Research Database (Denmark)

    Ernstsen, Christina L; Login, Frédéric H; Jensen, Helene H

    2017-01-01

    To target bacterial pathogens that invade and proliferate inside host cells, it is necessary to design intervention strategies directed against bacterial attachment, cellular invasion and intracellular proliferation. We present an automated microscopy-based, fast, high-throughput method for analy...

  5. Electron Microscopy of Intracellular Protozoa

    Science.gov (United States)

    1988-12-20

    Classification) " ELECTRON MICROSCOPY OF INTRACELLULAR PROTOZOA 12. PERSONAL AUTHOR(S) Aikawa, Masamichi 13a. TYPE OF REPORT I13b. TIME COVERED 114...authors suggest that anti-CS protein antibody is important in reducing the prevalence of malaria with increasing age among persons in such areas and... Hygine 33, 220-226. 0Giudice, G.D., Engers, H.D., Tougne, C., Biro, S.S., Weiss, N., Verdini, A.S., Pessi, A., Degremont, A.A., Freyvogel, T.A., Lambert

  6. Modulation of pathogen recognition by autophagy

    Directory of Open Access Journals (Sweden)

    Ji Eun eOh

    2012-03-01

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

  7. Promotion and Rescue of Intracellular Brucella neotomae Replication during Coinfection with Legionella pneumophila.

    Science.gov (United States)

    Kang, Yoon-Suk; Kirby, James E

    2017-05-01

    We established a new Brucella neotomae in vitro model system for study of type IV secretion system-dependent (T4SS) pathogenesis in the Brucella genus. Importantly, B. neotomae is a rodent pathogen, and unlike B. abortus , B. melitensis , and B. suis , B. neotomae has not been observed to infect humans. It therefore can be handled more facilely using biosafety level 2 practices. More particularly, using a series of novel fluorescent protein and lux operon reporter systems to differentially label pathogens and track intracellular replication, we confirmed T4SS-dependent intracellular growth of B. neotomae in macrophage cell lines. Furthermore, B. neotomae exhibited early endosomal (LAMP-1) and late endoplasmic reticulum (calreticulin)-associated phagosome maturation. These findings recapitulate prior observations for human-pathogenic Brucella spp. In addition, during coinfection experiments with Legionella pneumophila , we found that defective intracellular replication of a B. neotomae T4SS virB4 mutant was rescued and baseline levels of intracellular replication of wild-type B. neotomae were significantly stimulated by coinfection with wild-type but not T4SS mutant L. pneumophila Using confocal microscopy, it was determined that intracellular colocalization of B. neotomae and L. pneumophila was required for rescue and that colocalization came at a cost to L. pneumophila fitness. These findings were not completely expected based on known temporal and qualitative differences in the intracellular life cycles of these two pathogens. Taken together, we have developed a new system for studying in vitro Brucella pathogenesis and found a remarkable T4SS-dependent interplay between Brucella and Legionella during macrophage coinfection. Copyright © 2017 American Society for Microbiology.

  8. The impact of regulatory obligations on fishers’ income

    DEFF Research Database (Denmark)

    Hadjimichael, Maria; J. Kaiser, Michel; Edwards-Jones, Gareth

    2013-01-01

    as a marketing tool to identify fishers’ most and least preferred regulatory obligations in terms of the impact these obligations have on their income. Significant differences were identified in fishers’ preferences that depended on the regulatory measures fishers operated under at the time of the study (which...

  9. 19 CFR 4.94 - Yacht privileges and obligations.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Yacht privileges and obligations. 4.94 Section 4... THE TREASURY VESSELS IN FOREIGN AND DOMESTIC TRADES General § 4.94 Yacht privileges and obligations...) A cruising license may be issued to a yacht of a foreign country only if it has been made to appear...

  10. Deconfounding Distance Effects in Judgments of Moral Obligation

    Science.gov (United States)

    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…

  11. 12 CFR 13.100 - Obligations concerning institutional customers.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Obligations concerning institutional customers... GOVERNMENT SECURITIES SALES PRACTICES Interpretations § 13.100 Obligations concerning institutional customers... to institutional customers. (b) The OCC's suitability rule (§ 13.4) is fundamental to fair dealing...

  12. 18 CFR 367.22 - Accounting for asset retirement obligations.

    Science.gov (United States)

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Accounting for asset... GAS ACT General Instructions § 367.22 Accounting for asset retirement obligations. (a) An asset... measurement changes to the initial liability for the legal obligation recorded in account 230, Asset...

  13. 16 CFR 436.2 - Obligation to furnish documents.

    Science.gov (United States)

    2010-01-01

    ... AND PROHIBITIONS CONCERNING FRANCHISING Franchisors' Obligations § 436.2 Obligation to furnish documents. In connection with the offer or sale of a franchise to be located in the United States of America... to the address specified by the prospective franchisee by first-class United States mail at least...

  14. Displacement and gratitude: accounting for the political obligation of refugees

    Directory of Open Access Journals (Sweden)

    Jason D'Cruz

    2014-03-01

    Full Text Available On what basis, and to what extent, are refugees obligated to obey the laws of their host countries? Consideration of the specific case of asylum-seekers generates, I think, two competing intuitions: (1 the refugee has a prima facie obligation to obey the laws of her host country and (2 none of the popularly canvassed substrates of political obligation—consent, tacit consent, fairness, or social role—is at all apt to explain the presence of this obligation. I contend that the unfashionable gratitude account of political obligation does the best job of accounting for the intuitions. As has been noticed by other commentators, obligations of gratitude are difficult to specify and subject to numerous cancelling conditions. I analyze these conditions in detail and conclude that if one accepts that gratitude is the basis of the political obligation of the refugee, then one must face up to just how frangible the obligation is. In particular, the obligation is conditional on the fair and generous treatment of refugees that is consistent with their dignity as human beings.

  15. [Long-term storage of obligate anaerobic microorganisms in glycerol].

    Science.gov (United States)

    Briukhanov, A I; Netrusov, A I

    2006-01-01

    We evaluated the possibility of storing the cultures of obligate anaerobic microorganisms (clostridia. acetogenic and sulfate-reducing bacteria, and methanogenic archaea) in 25% glycerol at -70 degrees C for a long time (up to 3 years). This method of storage is adequate to preserve cell viability in most obligate anaerobes.

  16. 7 CFR 400.166 - Obligations of the Corporation.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Obligations of the Corporation. 400.166 Section 400... CORPORATION, DEPARTMENT OF AGRICULTURE GENERAL ADMINISTRATIVE REGULATIONS Reinsurance Agreement-Standards for... Corporation. The Agreement will include the following among the obligations of the Corporation. (a) The...

  17. 7 CFR 1755.27 - Borrower contractual obligations.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Borrower contractual obligations. 1755.27 Section 1755.27 Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES SERVICE... CONTRACT FORMS § 1755.27 Borrower contractual obligations. (a) Loan agreement. As a condition of a loan or...

  18. 29 CFR 4.146 - Contract obligations after award, generally.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Contract obligations after award, generally. 4.146 Section 4.146 Labor Office of the Secretary of Labor LABOR STANDARDS FOR FEDERAL SERVICE CONTRACTS Application of the McNamara-O'Hara Service Contract Act Period of Coverage § 4.146 Contract obligations after...

  19. 49 CFR 371.10 - Duties and obligations of brokers.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Duties and obligations of brokers. 371.10 Section... SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR CARRIER SAFETY REGULATIONS BROKERS OF PROPERTY § 371.10 Duties and obligations of brokers. Where the broker acts on behalf of a person bound by...

  20. Social categories as markers of intrinsic interpersonal obligations.

    Science.gov (United States)

    Rhodes, Marjorie; Chalik, Lisa

    2013-06-01

    Social categorization is an early-developing feature of human social cognition, yet the role that social categories play in children's understanding of and predictions about human behavior has been unclear. In the studies reported here, we tested whether a foundational functional role of social categories is to mark people as intrinsically obligated to one another (e.g., obligated to protect rather than harm). In three studies, children (aged 3-9, N = 124) viewed only within-category harm as violating intrinsic obligations; in contrast, they viewed between-category harm as violating extrinsic obligations defined by explicit rules. These data indicate that children view social categories as marking patterns of intrinsic interpersonal obligations, suggesting that a key function of social categories is to support inferences about how people will relate to members of their own and other groups.

  1. Intracellular survival of Staphylococcus aureus during persistent infection in the insect Tenebrio molitor.

    Science.gov (United States)

    McGonigle, John E; Purves, Joanne; Rolff, Jens

    2016-06-01

    Survival of bacteria within host cells and tissues presents a challenge to the immune systems of higher organisms. Escape from phagocytic immune cells compounds this issue, as immune cells become potential vehicles for pathogen dissemination. However, the duration of persistence within phagocytes and its contribution to pathogen load has yet to be determined. We investigate the immunological significance of intracellular persistence within the insect model Tenebrio molitor, assessing the extent, duration and location of bacterial recovery during a persistent infection. Relative abundance of Staphylococcus aureus in both intracellular and extracellular fractions was determined over 21 days, and live S. aureus were successfully recovered from both the hemolymph and within phagocytic immune cells across the entire time course. The proportion of bacteria recovered from within phagocytes also increased over time. Our results show that to accurately estimate pathogen load it is vital to account for bacteria persisting within immune cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Manipulation of host membranes by the bacterial pathogens Listeria, Francisella, Shigella and Yersinia.

    Science.gov (United States)

    Pizarro-Cerdá, Javier; Charbit, Alain; Enninga, Jost; Lafont, Frank; Cossart, Pascale

    2016-12-01

    Bacterial pathogens display an impressive arsenal of molecular mechanisms that allow survival in diverse host niches. Subversion of plasma membrane and cytoskeletal functions are common themes associated to infection by both extracellular and intracellular pathogens. Moreover, intracellular pathogens modify the structure/stability of their membrane-bound compartments and escape degradation from phagocytic or autophagic pathways. Here, we review the manipulation of host membranes by Listeria monocytogenes, Francisella tularensis, Shigella flexneri and Yersinia spp. These four bacterial model pathogens exemplify generalized strategies as well as specific features observed during bacterial infection processes. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. The membrane as the gatekeeper of infection: Cholesterol in host-pathogen interaction.

    Science.gov (United States)

    Kumar, G Aditya; Jafurulla, Md; Chattopadhyay, Amitabha

    2016-09-01

    The cellular plasma membrane serves as a portal for the entry of intracellular pathogens. An essential step for an intracellular pathogen to gain entry into a host cell therefore is to be able to cross the cell membrane. In this review, we highlight the role of host membrane cholesterol in regulating the entry of intracellular pathogens using insights obtained from work on the interaction of Leishmania and Mycobacterium with host cells. The entry of these pathogens is known to be dependent on host membrane cholesterol. Importantly, pathogen entry is inhibited either upon depletion (or complexation), or enrichment of membrane cholesterol. In other words, an optimum level of host membrane cholesterol is necessary for efficient infection by pathogens. In this overall context, we propose a general mechanism, based on cholesterol-induced conformational changes, involving cholesterol binding sites in host cell surface receptors that are implicated in this process. A therapeutic strategy targeting modulation of membrane cholesterol would have the advantage of avoiding the commonly encountered problem of drug resistance in tackling infection by intracellular pathogens. Insights into the role of host membrane cholesterol in pathogen entry would be instrumental in the development of novel therapeutic strategies to effectively tackle intracellular pathogenesis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wiser, R.

    2005-06-01

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

  5. Safety Training: a right or an obligation?

    CERN Multimedia

    HSE Unit

    2014-01-01

    CERN’s Safety Training programme currently offers around 50 classroom courses and 17 e-learning courses. Although anyone can attend any of these courses, some are compulsory for everyone working at CERN. In particular, “CERN Safety Introduction” and “Safety during LS1” are compulsory for all new arrivals.   The "Self-Rescue Mask" training course. Photo: Christoph Balle. However, depending on the type of activities, the type of workstation, the role you have been assigned (TSO, project leader, etc.) and/or the area where you will be working (e.g. confined spaces), you might be required to follow additional safety training provided by CERN. In accordance with the provisions of the CERN Safety Policy, members of the personnel must keep themselves informed of their obligations in terms of safety training and of the actions they must take to keep up to date. Most training courses are valid for three years, and as they reach the ...

  6. Mi Casa es Su Casa: how an intracellular symbiont manipulates host biology.

    Science.gov (United States)

    Bhattacharya, Tamanash; Newton, Irene L G

    2017-10-27

    Wolbachia pipientis, the most common intracellular infection on the planet, infects 40% of insects as well as nematodes, isopods and arachnids. Wolbachia are obligately intracellular and challenging to study; there are no genetic tools for manipulating Wolbachia nor can they be cultured outside of host cells. Despite these roadblocks, the research community has defined a set of Wolbachia loci involved in host interaction: Wolbachia effectors. Through the use of Drosophila genetics, surrogate systems and biochemistry, the field has begun to define the toolkit Wolbachia use for host manipulation. Below we review recent findings identifying these Wolbachia effectors and point to potential, as yet uncharacterized, links between known phenotypes induced by Wolbachia infection and predicted effectors. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  7. MR imaging of intracellular and extracellular deoxyhemoglobin

    International Nuclear Information System (INIS)

    Janick, P.A.; Grossman, R.I.; Asakura, T.

    1989-01-01

    MR imaging was performed on varying concentrations of intracellular and extracellular deoxyhemoglobin as well as varying proportions of deoxyhemoglobin and oxyhemoglobin in vitro at 1.5T with use of standard spin-echo and gradient-refocused spin sequences. This study indicates that susceptibility-induced T2 shortening occurs over a broad range of intracellular deoxyhemoglobin concentrations (maximal at hematocrits between 20% and 45%), reflecting diffusional effects at the cellular level. T2* gradient-echo imaging enhances the observed hypointensity in images of intracellular deoxyhemoglobin. The characteristic MR appearance of acute hemotomas can be modeled by the behavior of intracellular and extracellular deoxyhemoglobin and oxyhemoglobin

  8. NAD+-Glycohydrolase Promotes Intracellular Survival of Group A Streptococcus.

    Directory of Open Access Journals (Sweden)

    Onkar Sharma

    2016-03-01

    Full Text Available A global increase in invasive infections due to group A Streptococcus (S. pyogenes or GAS has been observed since the 1980s, associated with emergence of a clonal group of strains of the M1T1 serotype. Among other virulence attributes, the M1T1 clone secretes NAD+-glycohydrolase (NADase. When GAS binds to epithelial cells in vitro, NADase is translocated into the cytosol in a process mediated by streptolysin O (SLO, and expression of these two toxins is associated with enhanced GAS intracellular survival. Because SLO is required for NADase translocation, it has been difficult to distinguish pathogenic effects of NADase from those of SLO. To resolve the effects of the two proteins, we made use of anthrax toxin as an alternative means to deliver NADase to host cells, independently of SLO. We developed a novel method for purification of enzymatically active NADase fused to an amino-terminal fragment of anthrax toxin lethal factor (LFn-NADase that exploits the avid, reversible binding of NADase to its endogenous inhibitor. LFn-NADase was translocated across a synthetic lipid bilayer in vitro in the presence of anthrax toxin protective antigen in a pH-dependent manner. Exposure of human oropharyngeal keratinocytes to LFn-NADase in the presence of protective antigen resulted in cytosolic delivery of NADase activity, inhibition of protein synthesis, and cell death, whereas a similar construct of an enzymatically inactive point mutant had no effect. Anthrax toxin-mediated delivery of NADase in an amount comparable to that observed during in vitro infection with live GAS rescued the defective intracellular survival of NADase-deficient GAS and increased the survival of SLO-deficient GAS. Confocal microscopy demonstrated that delivery of LFn-NADase prevented intracellular trafficking of NADase-deficient GAS to lysosomes. We conclude that NADase mediates cytotoxicity and promotes intracellular survival of GAS in host cells.

  9. Proteomics of Plant Pathogenic Fungi

    Directory of Open Access Journals (Sweden)

    Raquel González-Fernández

    2010-01-01

    Full Text Available Plant pathogenic fungi cause important yield losses in crops. In order to develop efficient and environmental friendly crop protection strategies, molecular studies of the fungal biological cycle, virulence factors, and interaction with its host are necessary. For that reason, several approaches have been performed using both classical genetic, cell biology, and biochemistry and the modern, holistic, and high-throughput, omic techniques. This work briefly overviews the tools available for studying Plant Pathogenic Fungi and is amply focused on MS-based Proteomics analysis, based on original papers published up to December 2009. At a methodological level, different steps in a proteomic workflow experiment are discussed. Separate sections are devoted to fungal descriptive (intracellular, subcellular, extracellular and differential expression proteomics and interactomics. From the work published we can conclude that Proteomics, in combination with other techniques, constitutes a powerful tool for providing important information about pathogenicity and virulence factors, thus opening up new possibilities for crop disease diagnosis and crop protection.

  10. Trade-Offs of Escherichia coli Adaptation to an Intracellular Lifestyle in Macrophages.

    Directory of Open Access Journals (Sweden)

    M Azevedo

    Full Text Available The bacterium Escherichia coli exhibits remarkable genomic and phenotypic variation, with some pathogenic strains having evolved to survive and even replicate in the harsh intra-macrophage environment. The rate and effects of mutations that can cause pathoadaptation are key determinants of the pace at which E. coli can colonize such niches and become pathogenic. We used experimental evolution to determine the speed and evolutionary paths undertaken by a commensal strain of E. coli when adapting to intracellular life. We estimated the acquisition of pathoadaptive mutations at a rate of 10-6 per genome per generation, resulting in the fixation of more virulent strains in less than a hundred generations. Whole genome sequencing of independently evolved clones showed that the main targets of intracellular adaptation involved loss of function mutations in genes implicated in the assembly of the lipopolysaccharide core, iron metabolism and di- and tri-peptide transport, namely rfaI, fhuA and tppB, respectively. We found a substantial amount of antagonistic pleiotropy in evolved populations, as well as metabolic trade-offs, commonly found in intracellular bacteria with reduced genome sizes. Overall, the low levels of clonal interference detected indicate that the first steps of the transition of a commensal E. coli into intracellular pathogens are dominated by a few pathoadaptive mutations with very strong effects.

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Physicians' strikes and the competing bases of physicians' moral obligations.

    Science.gov (United States)

    MacDougall, D Robert

    2013-09-01

    Many authors have addressed the morality of physicians' strikes on the assumption that medical practice is morally different from other kinds of occupations. This article analyzes three prominent theoretical accounts that attempt to ground such special moral obligations for physicians--practice-based accounts, utilitarian accounts, and social contract accounts--and assesses their applicability to the problem of the morality of strikes. After critiquing these views, it offers a fourth view grounding special moral obligations in voluntary commitments, and explains why this is a preferable basis for understanding physicians' moral obligations in general and especially as pertaining to strikes.

  13. The Arabidopsis microtubule-associated protein MAP65-3 supports infection by filamentous biotrophic pathogens by down-regulating salicylic acid-dependent defenses.

    Science.gov (United States)

    Quentin, Michaël; Baurès, Isabelle; Hoefle, Caroline; Caillaud, Marie-Cécile; Allasia, Valérie; Panabières, Franck; Abad, Pierre; Hückelhoven, Ralph; Keller, Harald; Favery, Bruno

    2016-03-01

    The oomycete Hyaloperonospora arabidopsidis and the ascomycete Erysiphe cruciferarum are obligate biotrophic pathogens causing downy mildew and powdery mildew, respectively, on Arabidopsis. Upon infection, the filamentous pathogens induce the formation of intracellular bulbous structures called haustoria, which are required for the biotrophic lifestyle. We previously showed that the microtubule-associated protein AtMAP65-3 plays a critical role in organizing cytoskeleton microtubule arrays during mitosis and cytokinesis. This renders the protein essential for the development of giant cells, which are the feeding sites induced by root knot nematodes. Here, we show that AtMAP65-3 expression is also induced in leaves upon infection by the downy mildew oomycete and the powdery mildew fungus. Loss of AtMAP65-3 function in the map65-3 mutant dramatically reduced infection by both pathogens, predominantly at the stages of leaf penetration. Whole-transcriptome analysis showed an over-represented, constitutive activation of genes involved in salicylic acid (SA) biosynthesis, signaling, and defense execution in map65-3, whereas jasmonic acid (JA)-mediated signaling was down-regulated. Preventing SA synthesis and accumulation in map65-3 rescued plant susceptibility to pathogens, but not the developmental phenotype caused by cytoskeleton defaults. AtMAP65-3 thus has a dual role. It positively regulates cytokinesis, thus plant growth and development, and negatively interferes with plant defense against filamentous biotrophs. Our data suggest that downy mildew and powdery mildew stimulate AtMAP65-3 expression to down-regulate SA signaling for infection. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  14. Emerging Pathogens Initiative (EPI)

    Data.gov (United States)

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

  15. Metabolic Cooperation of Glucose and Glutamine Is Essential for the Lytic Cycle of Obligate Intracellular Parasite Toxoplasma gondii*

    OpenAIRE

    Nitzsche, Richard; Zagoriy, Vyacheslav; Lucius, Richard; Gupta, Nishith

    2015-01-01

    Toxoplasma gondii is a widespread protozoan parasite infecting nearly all warm-blooded organisms. Asexual reproduction of the parasite within its host cells is achieved by consecutive lytic cycles, which necessitates biogenesis of significant energy and biomass. Here we show that glucose and glutamine are the two major physiologically important nutrients used for the synthesis of macromolecules (ATP, nucleic acid, proteins, and lipids) in T. gondii, and either of them is sufficient to ensure ...

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

    Science.gov (United States)

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

    2017-01-01

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

  17. Dynamics of intracellular information decoding

    International Nuclear Information System (INIS)

    Kobayashi, Tetsuya J; Kamimura, Atsushi

    2011-01-01

    A variety of cellular functions are robust even to substantial intrinsic and extrinsic noise in intracellular reactions and the environment that could be strong enough to impair or limit them. In particular, of substantial importance is cellular decision-making in which a cell chooses a fate or behavior on the basis of information conveyed in noisy external signals. For robust decoding, the crucial step is filtering out the noise inevitably added during information transmission. As a minimal and optimal implementation of such an information decoding process, the autocatalytic phosphorylation and autocatalytic dephosphorylation (aPadP) cycle was recently proposed. Here, we analyze the dynamical properties of the aPadP cycle in detail. We describe the dynamical roles of the stationary and short-term responses in determining the efficiency of information decoding and clarify the optimality of the threshold value of the stationary response and its information-theoretical meaning. Furthermore, we investigate the robustness of the aPadP cycle against the receptor inactivation time and intrinsic noise. Finally, we discuss the relationship among information decoding with information-dependent actions, bet-hedging and network modularity

  18. Dynamics of intracellular information decoding.

    Science.gov (United States)

    Kobayashi, Tetsuya J; Kamimura, Atsushi

    2011-10-01

    A variety of cellular functions are robust even to substantial intrinsic and extrinsic noise in intracellular reactions and the environment that could be strong enough to impair or limit them. In particular, of substantial importance is cellular decision-making in which a cell chooses a fate or behavior on the basis of information conveyed in noisy external signals. For robust decoding, the crucial step is filtering out the noise inevitably added during information transmission. As a minimal and optimal implementation of such an information decoding process, the autocatalytic phosphorylation and autocatalytic dephosphorylation (aPadP) cycle was recently proposed. Here, we analyze the dynamical properties of the aPadP cycle in detail. We describe the dynamical roles of the stationary and short-term responses in determining the efficiency of information decoding and clarify the optimality of the threshold value of the stationary response and its information-theoretical meaning. Furthermore, we investigate the robustness of the aPadP cycle against the receptor inactivation time and intrinsic noise. Finally, we discuss the relationship among information decoding with information-dependent actions, bet-hedging and network modularity.

  19. HYPERTHERMIA, INTRACELLULAR FREE CALCIUM AND CALCIUM IONOPHORES

    NARCIS (Netherlands)

    STEGE, GJJ; WIERENGA, PK; KAMPINGA, HH; KONINGS, AWT

    1993-01-01

    It is shown that heat-induced increase of intracellular calcium does not correlate with hyperthermic cell killing. Six different cell lines were investigated; in four (EAT, HeLa S3, L5178Y-R and L5178Y-S) heat treatments killing 90% of the cells did not affect the levels of intracellular free

  20. Resolving Conflicts between Beliefs, Obligations, Intentions, and Desires

    NARCIS (Netherlands)

    Broersen, J.M.; Dastani, M.M.; Torre, L. van der

    2001-01-01

    This paper provides a logical analysis of conflicts between informational, motivational and deliberative attitudes such as beliefs, obligations, intentions, and desires. The contributions are twofold. First, conflict resolutions are classi ed based on agent types, and formalized in an extension

  1. NSF Obligations for Top 200 Institutions by Fiscal Year

    Data.gov (United States)

    National Science Foundation — An text/xml file containing FY 2001 through FY 2015 National Science Foundation (NSF) obligations by institution for the top 200 recipients defined in terms of total...

  2. 47 CFR 76.56 - Signal carriage obligations.

    Science.gov (United States)

    2010-10-01

    ... qualified local NCE station affiliated with a State public television network shall not be required to carry... stations in fulfillment of these must-carry obligations may do so, subject to approval by the franchising...

  3. 18 CFR 154.315 - Asset retirement obligations.

    Science.gov (United States)

    2010-04-01

    ... retirement obligations that would impact the calculation of rate base, such as gas plant and related accumulated depreciation and accumulated deferred income taxes, may not be reflected in rates and must be...

  4. 18 CFR 346.3 - Asset retirement obligations.

    Science.gov (United States)

    2010-04-01

    ... related to asset retirement obligations that would impact the calculation of rate base, such as carrier property and related accumulated depreciation and accumulated deferred income taxes, may not be reflected...

  5. 18 CFR 35.18 - Asset retirement obligations.

    Science.gov (United States)

    2010-04-01

    ... related to asset retirement obligations that would impact the calculation of rate base, such as electric plant and related accumulated depreciation and accumulated deferred income taxes, may not be reflected...

  6. SDC Supplier Obligation project : household energy from 2011 : final report

    OpenAIRE

    Sustainable Development Commission

    2008-01-01

    This report is based on 'SDC Supplier Obligation engagement project : process plan'. Evaluation of the engagement process used in this report can be found in 'SDC Supplier Obligation project : an evaluation of the Sustainable Development Commission's stakeholder and public engagement process'. This report presents the findings of the Sustainable Development Commission’s stakeholder and public engagement process and informs the development of Department for Environment, Food and Rural Af...

  7. THE SELLER'S OBLIGATION TO DELIVER THE GOODS ACCORDING TO CISG

    Directory of Open Access Journals (Sweden)

    Dan VELICU

    2017-05-01

    Full Text Available This article aims to analyze the seller's obligations under the Convention on International Sale of Goods (CISG and in particular the obligation to deliver the goods showing the main issues that arise in an international sale. We also wish to point the major innovations or improvements brought by the CISG in comparison to the European civil codes regulation and to conclude if the CSIG managed to revolutionize the tradition view on this issue.

  8. Novation as a method of termination of obligations

    OpenAIRE

    Perović Marko

    2017-01-01

    The paper presents an analysis of the issue of novation in contract law. Novation is a contract between the creditor and debtor in order to replace its existing obligation with a new one. Unlike the other methods of termination of obligations (e.g. fulfillment, compensation, remission of debt), novation extinguishes existing contractual relationship between the creditor and the debtor, so that among them arise a new contractual relationship, which in relation to the previous one, differs on t...

  9. Contractual and non-contractuall obligations in private international Law

    OpenAIRE

    Čejková, Martina

    2010-01-01

    67 8 Summary 8.1 Contractual and Non-contractual Obligations in Private International Law This thesis deals with the European international private law and discusses the current law-crash modification of contractual and non-contractual obligations. Characteristic of the European community is the absence of unification of the substantive law, which is compensated, by the unification of conflict standards. The unification of conflict standards, as an instrument of the international private law,...

  10. Lessee's obligations under the oil and gas lease

    International Nuclear Information System (INIS)

    Malcolm, R.T.

    1998-01-01

    Obligations of a lessee under the present day freehold petroleum and natural gas lease are described. The effect of recent cases relating to fiduciary and good faith duties on the lessee's obligations are also examined. Every lease under the Canadian Association of Petroleum Landmen (CAPL) must specifically deal with rights to be granted, the obligations to drill, royalties, the length of the primary term, the amount of the rental rights, rights to pool, and offset obligations. In Alberta, the most accepted petroleum and natural gas lease form is the CAPL 91. This form is presently being revised to create the 1998 version. The contents of this discussion included: (1) historical lease interpretation, (2) fiduciary obligations, (3) the definition of the doctrine of good faith, (4) implied and express covenants, (5) application of the default clause and (6) force majeur provisions. Although Alberta law does not recognize the doctrine of good faith, nevertheless the court will review the obligations of the lessee and if they do not feel that the lessee has acted fairly with respect to the lessor and damages have resulted, the court will find for the lessor

  11. Brucella abortus nicotinamidase (PncA) contributes to its intracellular replication and infectivity in mice.

    Science.gov (United States)

    Kim, Suk; Kurokawa, Daisuke; Watanabe, Kenta; Makino, Sou-Ichi; Shirahata, Toshikazu; Watarai, Masahisa

    2004-05-15

    Brucella spp. are facultative intracellular pathogens that have the ability to survive and multiply in professional and non-professional phagocytes, and cause abortion in domestic animals and undulant fever in humans. The mechanism and factors of virulence are not fully understood. Nicotinamidase/pyrazinamidase mutant (pncA mutant) of Brucella abortus failed to replicate in HeLa cells, and showed a lower rate of intracellular replication than that of wild-type strain in macrophages. Addition of nicotinic acid, but not nicotinamide, into medium supported intracellular replication of pncA mutant in HeLa cells and macrophages. The pncA mutant was not co-localizing with either late endosomes or lysosomes. The B. abortus virB4 mutant was completely cleared from the spleens of mice after 4 weeks, while the pncA mutant showed a 1.5-log reduction of the number of bacteria isolated from spleens after 10 weeks. Although pncA mutant showed reduced virulence in mice and defective intracellular replication, its ability to confer protection against the virulent B. abortus strain 544 was fully retained. These results suggest that PncA does not contribute to intracellular trafficking of B. abortus, but contributes to utilization of nutrients required for intracellular growth. Our results indicate that detailed characterizations of the pncA mutant may help the improvement of currently available live vaccines. Copyright 2004 Federation of European Microbiological Societies

  12. Where to place the saving obligation: Energy end-users or suppliers?

    International Nuclear Information System (INIS)

    Bertoldi, Paolo; Labanca, Nicola; Rezessy, Silvia; Steuwer, Sibyl; Oikonomou, Vlasis

    2013-01-01

    Obligations to save energy differentiate, among other features, by obliged parties. These are obligations on energy suppliers and energy end-users. Supplier obligations have been introduced in North America, Europe and Australia. Under supplier obligations energy suppliers have to comply with mandatory energy saving targets and thus they implement (directly or via third parties) energy efficiency projects on their clients’ premises, or they decide to trade certified project savings if this option is envisaged by their obligation scheme. In several emerging schemes such as the UK Carbon Reduction Commitment (CRC) Energy Efficiency Scheme, the Tokyo Emission Trading Scheme or the Perform Achieve and Trade (PAT) Scheme in India, the obligation to reduce energy consumption is placed on large end-users directly and end-users are allowed to trade emissions allowances or energy saving certificates. The paper starts with presenting these two conceptually different ways for introducing energy saving obligations. Then it analyses advantages and disadvantages of end-users obligations compared to suppliers obligations. The preliminary conclusion of the paper is that supplier obligations seem to be well-suited for the residential sector, but end-user saving obligations may offer advantages when it comes to the industrial and commercial sectors. - Highlights: • We present different ways for introducing energy saving obligations. • We analyse energy end-users obligations vs. supplier obligations. • Supplier obligations seem to be well-suited for the residential sector. • End-user obligations offer advantages in the industrial and commercial sectors

  13. Intracellular localization of Arabidopsis sulfurtransferases.

    Science.gov (United States)

    Bauer, Michael; Dietrich, Christof; Nowak, Katharina; Sierralta, Walter D; Papenbrock, Jutta

    2004-06-01

    Sulfurtransferases (Str) comprise a group of enzymes widely distributed in archaea, eubacteria, and eukaryota which catalyze the transfer of a sulfur atom from suitable sulfur donors to nucleophilic sulfur acceptors. In all organisms analyzed to date, small gene families encoding Str proteins have been identified. The gene products were localized to different compartments of the cells. Our interest concerns the localization of Str proteins encoded in the nuclear genome of Arabidopsis. Computer-based prediction methods revealed localization in different compartments of the cell for six putative AtStrs. Several methods were used to determine the localization of the AtStr proteins experimentally. For AtStr1, a mitochondrial localization was demonstrated by immunodetection in the proteome of isolated mitochondria resolved by one- and two-dimensional gel electrophoresis and subsequent blotting. The respective mature AtStr1 protein was identified by mass spectrometry sequencing. The same result was obtained by transient expression of fusion constructs with the green fluorescent protein in Arabidopsis protoplasts, whereas AtStr2 was exclusively localized to the cytoplasm by this method. Three members of the single-domain AtStr were localized in the chloroplasts as demonstrated by transient expression of green fluorescent protein fusions in protoplasts and stomata, whereas the single-domain AtStr18 was shown to be cytoplasmic. The remarkable subcellular distribution of AtStr15 was additionally analyzed by transmission electron immunomicroscopy using a monospecific antibody against green fluorescent protein, indicating an attachment to the thylakoid membrane. The knowledge of the intracellular localization of the members of this multiprotein family will help elucidate their specific functions in the organism.

  14. Intracellular calcium homeostasis and signaling.

    Science.gov (United States)

    Brini, Marisa; Calì, Tito; Ottolini, Denis; Carafoli, Ernesto

    2013-01-01

    Ca(2+) is a universal carrier of biological information: it controls cell life from its origin at fertilization to its end in the process of programmed cell death. Ca(2+) is a conventional diffusible second messenger released inside cells by the interaction of first messengers with plasma membrane receptors. However, it can also penetrate directly into cells to deliver information without the intermediation of first or second messengers. Even more distinctively, Ca(2+) can act as a first messenger, by interacting with a plasma membrane receptor to set in motion intracellular signaling pathways that involve Ca(2+) itself. Perhaps the most distinctive property of the Ca(2+) signal is its ambivalence: while essential to the correct functioning of cells, Ca(2+) becomes an agent that mediates cell distress, or even (toxic) cell death, if its concentration and movements inside cells are not carefully tuned. Ca(2+) is controlled by reversible complexation to specific proteins, which could be pure Ca(2+) buffers, or which, in addition to buffering Ca(2+), also decode its signal to pass it on to targets. The most important actors in the buffering of cell Ca(2+) are proteins that transport it across the plasma membrane and the membrane of the organelles: some have high Ca(2+) affinity and low transport capacity (e.g., Ca(2+) pumps), others have opposite properties (e.g., the Ca(2+) uptake system of mitochondria). Between the initial event of fertilization, and the terminal event of programmed cell death, the Ca(2+) signal regulates the most important activities of the cell, from the expression of genes, to heart and muscle contraction and other motility processes, to diverse metabolic pathways involved in the generation of cell fuels.

  15. Clinical significance and epidemiologic analyses of Mycobacterium avium and Mycobacterium intracellulare lung disease from post-marketing surveillance.

    Science.gov (United States)

    Suzuki, Katsuhiro; Kurashima, Atsuyuki; Tatsuno, Kinji; Kadota, Jun-Ichi

    2018-01-01

    In Japan, nontuberculous mycobacterial lung disease is mostly attributable to Mycobacterium avium complex (MAC), i.e., M. avium or M. intracellulare. However, clinical features of the disease caused by these two pathogens have not been studied sufficiently yet. A post-marketing survey of clarithromycin was performed at 130 facilities across Japan. The data on patients with M. avium infection and patients with M. intracellulare infection were selected from this survey for comparison of background variables and clinical features of the two pathogens. Among the patients analyzed (n = 368), 67.4% had M. avium infection and 32.6% had M. intracellulare infection. Stratified analysis revealed no significant differences between the ratio of the two pathogens based on gender, disease type, complication, past medical history, or smoking history. However, the percentage of patients with M. intracellulare infection was significantly higher among those with underlying lung disease than among those without lung disease (p = 0.0217). The percentage of patients with M. intracellulare infection rose significantly with age (p = 0.0296). This age-related change was more significant in women (p = 0.0018). When district-wise analysis was performed for Japan, the percentage of M. intracellulare infection was higher in the Chugoku/Shikoku and Kyushu districts whereas the percentage of M. avium infection was higher in the other districts. This survey revealed some differences in the clinical and epidemiologic features of M. avium and M. intracellulare infection. The significant predominance of M. avium infection among relatively young women is suggestive of an increase in the M. avium/M. intracellulare infection ratio among women in the future. Copyright © 2017 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.

  16. Consequences of reductive evolution for gene expression in an obligate endosymbiont.

    Science.gov (United States)

    Wilcox, Jennifer L; Dunbar, Helen E; Wolfinger, Russell D; Moran, Nancy A

    2003-06-01

    The smallest cellular genomes are found in obligate symbiotic and pathogenic bacteria living within eukaryotic hosts. In comparison with large genomes of free-living relatives, these reduced genomes are rearranged and have lost most regulatory elements. To test whether reduced bacterial genomes incur reduced regulatory capacities, we used full-genome microarrays to evaluate transcriptional response to environmental stress in Buchnera aphidicola, the obligate endosymbiont of aphids. The 580 genes of the B. aphidicola genome represent a subset of the 4500 genes known from the related organism, Escherichia coli. Although over 20 orthologues of E. coli heat stress (HS) genes are retained by B. aphidicola, only five were differentially expressed after near-lethal heat stress treatments, and only modest shifts were observed. Analyses of upstream regulatory regions revealed loss or degradation of most HS (sigma32) promoters. Genomic rearrangements downstream of an intact HS promoter yielded upregulation of a functionally unrelated and an inactivated gene. Reanalyses of comparable experimental array data for E. coli and Bacillus subtilis revealed that genome-wide differential expression was significantly lower in B. aphidicola. Our demonstration of a diminished stress response validates reports of temperature sensitivity in B. aphidicola and suggests that this reduced bacterial genome exhibits transcriptional inflexibility.

  17. Isolation of obligate anaerobic bacteria from ulcerative keratitis in domestic animals.

    Science.gov (United States)

    Ledbetter, Eric C; Scarlett, Janet M

    2008-01-01

    To determine the frequency of obligate anaerobic bacterial isolation from corneal samples of domestic animals with ulcerative keratitis and to characterize the historical, clinical, cytological, and microbiological features of culture-positive cases. Three hundred and thirty domestic animals with ulcerative keratitis. Anaerobic bacteriologic culture and Gram stain were performed on corneal samples from consecutive animals examined with suspect septic ulcerative keratitis. Additional corneal diagnostics included: aerobic bacteriologic culture for all species; fungal culture for ungulates; Mycoplasma culture and virus isolation or feline herpesvirus-1 (FHV-1) polymerase chain reaction (PCR) for cats. Historical, clinical, and cytological findings were correlated with microbiologic data. Anaerobic bacteria were isolated from 13.0% of corneal samples (dogs: 14.0%; horses: 12.9%; cats: 7.9%; alpacas: 18.8%). The most frequent isolates were Clostridium, Peptostreptococcus, Actinomyces, Fusobacterium, and Bacteroides species. The majority of these infections were mixed anaerobic and aerobic bacteria, unless antimicrobial therapy had been administered prior to presentation. The clinical appearance of anaerobic bacterial culture-positive cases was highly variable. Ocular trauma, pre-existing corneal disease, previous corneal surgery, and chronic dermatological disease were significantly (P anaerobic cultures in one or more species. The results of the present study demonstrate that obligate anaerobic bacteria are present within the intralesional flora of ulcerative keratitis in domestic animals. In most species evaluated, these bacteria were identified infrequently. Anaerobic bacterial infection of the cornea most frequently occurs in association with other ocular pathogens and previous corneal abnormalities.

  18. Delineation of diverse macrophage activation programs in response to intracellular parasites and cytokines.

    Directory of Open Access Journals (Sweden)

    Shuyi Zhang

    2010-03-01

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

  19. Nanoparticles for intracellular-targeted drug delivery

    International Nuclear Information System (INIS)

    Paulo, Cristiana S O; Pires das Neves, Ricardo; Ferreira, Lino S

    2011-01-01

    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.

  20. Biological synthesis and characterization of intracellular gold ...

    Indian Academy of Sciences (India)

    thods of reduction of metal ions using plants or microorganisms are often ... have several advantages over bacteria, they are often pre- ferred. ... in static condition for a period of 7 days. ... work was focused on the production of intracellular gold.

  1. Effector-triggered immunity: from pathogen perception to robust defense.

    Science.gov (United States)

    Cui, Haitao; Tsuda, Kenichi; Parker, Jane E

    2015-01-01

    In plant innate immunity, individual cells have the capacity to sense and respond to pathogen attack. Intracellular recognition mechanisms have evolved to intercept perturbations by pathogen virulence factors (effectors) early in host infection and convert it to rapid defense. One key to resistance success is a polymorphic family of intracellular nucleotide-binding/leucine-rich-repeat (NLR) receptors that detect effector interference in different parts of the cell. Effector-activated NLRs connect, in various ways, to a conserved basal resistance network in order to transcriptionally boost defense programs. Effector-triggered immunity displays remarkable robustness against pathogen disturbance, in part by employing compensatory mechanisms within the defense network. Also, the mobility of some NLRs and coordination of resistance pathways across cell compartments provides flexibility to fine-tune immune outputs. Furthermore, a number of NLRs function close to the nuclear chromatin by balancing actions of defense-repressing and defense-activating transcription factors to program cells dynamically for effective disease resistance.

  2. PKC-η-MARCKS Signaling Promotes Intracellular Survival of Unopsonized Burkholderia thailandensis.

    Science.gov (United States)

    Micheva-Viteva, Sofiya N; Shou, Yulin; Ganguly, Kumkum; Wu, Terry H; Hong-Geller, Elizabeth

    2017-01-01

    Pathogenic Burkholderia rely on host factors for efficient intracellular replication and are highly refractory to antibiotic treatment. To identify host genes that are required by Burkholderia spp. during infection, we performed a RNA interference (RNAi) screen of the human kinome and identified 35 host kinases that facilitated Burkholderia thailandensis intracellular survival in human monocytic THP-1 cells. We validated a selection of host kinases using imaging flow cytometry to assess efficiency of B. thailandensis survival in the host upon siRNA-mediated knockdown. We focused on the role of the novel protein kinase C isoform, PKC-η, in Burkholderia infection and characterized PKC-η/MARCKS signaling as a key event that promotes the survival of unopsonized B. thailandensis CDC2721121 within host cells. While infection of lung epithelial cells with unopsonized Gram-negative bacteria stimulated phosphorylation of Ser175/160 in the MARCKS effector domain, siRNA-mediated knockdown of PKC-η expression reduced the levels of phosphorylated MARCKS by >3-fold in response to infection with Bt CDC2721121. We compared the effect of the conventional PKC-α and novel PKC-η isoforms on the growth of B. thailandensis CDC2721121 within monocytic THP-1 cells and found that ≥75% knock-down of PRKCH transcript levels reduced intracellular bacterial load 100% more efficiently when compared to growth in cells siRNA-depleted of the classical PKC-α, suggesting that the PKC-η isoform can specifically mediate Burkholderia intracellular survival. Based on imaging studies of intracellular B. thailandensis , we found that PKC-η function stimulates phagocytic pathways that promote B. thailandensis escape into the cytoplasm leading to activation of autophagosome flux. Identification of host kinases that are targeted by Burkholderia during infection provides valuable molecular insights in understanding Burkholderia pathogenesis, and ultimately, in designing effective host

  3. The Propeptide of the Metalloprotease of Listeria monocytogenes Controls Compartmentalization of the Zymogen during Intracellular Infection▿

    OpenAIRE

    O'Neil, Heather S.; Forster, Brian M.; Roberts, Kari L.; Chambers, Andrew J.; Bitar, Alan Pavinski; Marquis, Hélène

    2009-01-01

    Integral to the virulence of the intracellular bacterial pathogen Listeria monocytogenes is its metalloprotease (Mpl). Mpl regulates the activity and compartmentalization of the bacterial broad-range phospholipase C (PC-PLC). Mpl is secreted as a proprotein that undergoes intramolecular autocatalysis to release its catalytic domain. In related proteases, the propeptide serves as a folding catalyst and can act either in cis or in trans. Propeptides can also influence protein compartmentalizati...

  4. Regular periodical public disclosure obligations of public companies

    Directory of Open Access Journals (Sweden)

    Marjanski Vladimir

    2011-01-01

    Full Text Available Public companies in the capacity of capital market participants have the obligation to inform the public on their legal and financial status, their general business operations, as well as on the issuance of securities and other financial instruments. Such obligations may be divided into two groups: The first group consists of regular periodical public disclosures, such as the publication of financial reports (annual, semi-annual and quarterly, and the management's reports on the public company's business operations. The second group comprises the obligation of occasional (ad hoc public disclosure. The thesis analyses the obligation of public companies to inform the public in course of their regular reporting. The new Capital Market Law based on two EU Directives (the Transparency Directive and the Directive on Public Disclosure of Inside Information and the Definition of Market Manipulation regulates such obligation of public companies in substantially more detail than the prior Law on the Market of Securities and Other Financial Instruments (hereinafter: ZTHV. Due to the above the ZTHV's provisions are compared to the new solutions within the domain of regular periodical disclosure of the Capital Market Law.

  5. Mycobacterium intracellulare Infection Mimicking Progression of Scleroderma

    DEFF Research Database (Denmark)

    Krabbe, Simon; Engelhart, Merete; Thybo, Sören

    2017-01-01

    This case report describes a patient with scleroderma who developed Mycobacterium intracellulare infection, which for more than a year mimicked worsening of her connective tissue disorder. The patient was diagnosed with scleroderma based on puffy fingers that developed into sclerodactyly, abnormal......, unfortunately with significant scarring. Immunodeficiency testing was unremarkable. In summary, an infection with Mycobacterium intracellulare was mistaken for an unusually severe progression of scleroderma....

  6. Cyclic AMP Pathway Activation and Extracellular Zinc Induce Rapid Intracellular Zinc Mobilization in Candida albicans

    Science.gov (United States)

    Kjellerup, Lasse; Winther, Anne-Marie L.; Wilson, Duncan; Fuglsang, Anja T.

    2018-01-01

    Zinc is an essential micronutrient, required for a range of zinc-dependent enzymes and transcription factors. In mammalian cells, zinc serves as a second messenger molecule. However, a role for zinc in signaling has not yet been established in the fungal kingdom. Here, we used the intracellular zinc reporter, zinbo-5, which allowed visualization of zinc in the endoplasmic reticulum and other components of the internal membrane system in Candida albicans. We provide evidence for a link between cyclic AMP/PKA- and zinc-signaling in this major human fungal pathogen. Glucose stimulation, which triggers a cyclic AMP spike in this fungus resulted in rapid intracellular zinc mobilization and this “zinc flux” could be stimulated with phosphodiesterase inhibitors and blocked via inhibition of adenylate cyclase or PKA. A similar mobilization of intracellular zinc was generated by stimulation of cells with extracellular zinc and this effect could be reversed with the chelator EDTA. However, zinc-induced zinc flux was found to be cyclic AMP independent. In summary, we show that activation of the cyclic AMP/PKA pathway triggers intracellular zinc mobilization in a fungus. To our knowledge, this is the first described link between cyclic AMP signaling and zinc homeostasis in a human fungal pathogen. PMID:29619016

  7. The obligate respiratory supercomplex from Actinobacteria.

    Science.gov (United States)

    Kao, Wei-Chun; Kleinschroth, Thomas; Nitschke, Wolfgang; Baymann, Frauke; Neehaul, Yashvin; Hellwig, Petra; Richers, Sebastian; Vonck, Janet; Bott, Michael; Hunte, Carola

    2016-10-01

    Actinobacteria are closely linked to human life as industrial producers of bioactive molecules and as human pathogens. Respiratory cytochrome bcc complex and cytochrome aa3 oxidase are key components of their aerobic energy metabolism. They form a supercomplex in the actinobacterial species Corynebacterium glutamicum. With comprehensive bioinformatics and phylogenetic analysis we show that genes for cyt bcc-aa3 supercomplex are characteristic for Actinobacteria (Actinobacteria and Acidimicrobiia, except the anaerobic orders Actinomycetales and Bifidobacteriales). An obligatory supercomplex is likely, due to the lack of genes encoding alternative electron transfer partners such as mono-heme cyt c. Instead, subunit QcrC of bcc complex, here classified as short di-heme cyt c, will provide the exclusive electron transfer link between the complexes as in C. glutamicum. Purified to high homogeneity, the C. glutamicum bcc-aa3 supercomplex contained all subunits and cofactors as analyzed by SDS-PAGE, BN-PAGE, absorption and EPR spectroscopy. Highly uniform supercomplex particles in electron microscopy analysis support a distinct structural composition. The supercomplex possesses a dimeric stoichiometry with a ratio of a-type, b-type and c-type hemes close to 1:1:1. Redox titrations revealed a low potential bcc complex (Em(ISP)=+160mV, Em(bL)=-291mV, Em(bH)=-163mV, Em(cc)=+100mV) fined-tuned for oxidation of menaquinol and a mixed potential aa3 oxidase (Em(CuA)=+150mV, Em(a/a3)=+143/+317mV) mediating between low and high redox potential to accomplish dioxygen reduction. The generated molecular model supports a stable assembled supercomplex with defined architecture which permits energetically efficient coupling of menaquinol oxidation and dioxygen reduction in one supramolecular entity. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    OpenAIRE

    Choi, Chul Hee; DeGuzman, Jefferson V.; Lamont, Richard J.; Yilmaz, Özlem

    2011-01-01

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

  9. T3SS effector VopL inhibits the host ROS response, promoting the intracellular survival of Vibrio parahaemolyticus.

    Directory of Open Access Journals (Sweden)

    Marcela de Souza Santos

    2017-06-01

    Full Text Available The production of antimicrobial reactive oxygen species by the nicotinamide dinucleotide phosphate (NADPH oxidase complex is an important mechanism for control of invading pathogens. Herein, we show that the gastrointestinal pathogen Vibrio parahaemolyticus counteracts reactive oxygen species (ROS production using the Type III Secretion System 2 (T3SS2 effector VopL. In the absence of VopL, intracellular V. parahaemolyticus undergoes ROS-dependent filamentation, with concurrent limited growth. During infection, VopL assembles actin into non-functional filaments resulting in a dysfunctional actin cytoskeleton that can no longer mediate the assembly of the NADPH oxidase at the cell membrane, thereby limiting ROS production. This is the first example of how a T3SS2 effector contributes to the intracellular survival of V. parahaemolyticus, supporting the establishment of a protective intracellular replicative niche.

  10. A method for functional trans-complementation of intracellular Francisella tularensis.

    Directory of Open Access Journals (Sweden)

    Shaun Steele

    Full Text Available Francisella tularensis is a highly infectious bacterial pathogen that invades and replicates within numerous host cell types. After uptake, F. tularensis bacteria escape the phagosome, replicate within the cytosol, and suppress cytokine responses. However, the mechanisms employed by F. tularensis to thrive within host cells are mostly unknown. Potential F. tularensis mutants involved in host-pathogen interactions are typically discovered by negative selection screens for intracellular replication or virulence. Mutants that fulfill these criteria fall into two categories: mutants with intrinsic intracellular growth defects and mutants that fail to modify detrimental host cell processes. It is often difficult and time consuming to discriminate between these two possibilities. We devised a method to functionally trans-complement and thus identify mutants that fail to modify the host response. In this assay, host cells are consistently and reproducibly infected with two different F. tularensis strains by physically tethering the bacteria to antibody-coated beads. To examine the efficacy of this protocol, we tested phagosomal escape, cytokine suppression, and intracellular replication for F. tularensis ΔripA and ΔpdpC. ΔripA has an intracellular growth defect that is likely due to an intrinsic defect and fails to suppress IL-1β secretion. In the co-infection model, ΔripA was unable to replicate in the host cell when wild-type bacteria infected the same cell, but cytokine suppression was rescued. Therefore, ΔripA intracellular growth is due to an intrinsic bacterial defect while cytokine secretion results from a failed host-pathogen interaction. Likewise, ΔpdpC is deficient for phagosomal escape, intracellular survival and suppression of IL-1β secretion. Wild-type bacteria that entered through the same phagosome as ΔpdpC rescued all of these phenotypes, indicating that ΔpdpC failed to properly manipulate the host. In summary, functional

  11. [Analysis of DNA-DNA homologies in obligate methylotrophic bacteria].

    Science.gov (United States)

    Doronina, N V; Govorukhina, N I; Lysenko, A M; Trotsenko, Iu A

    1988-01-01

    The genotypic affinity of 19 bacterial strains obligately dependent on methanol or methylamine as carbon and energy sources was studied by techniques of molecular DNA hybridization. The high homology level (35-88%) between motile strain Methylophilus methanolovorus V-1447D and nonmotile strain Methylobacillus sp. VSB-792 as well as other motile strains (Pseudomonas methanolica ATCC 21704, Methylomonas methanolica NRRL 5458, Pseudomonas sp. W6, strain A3) indicates that all of them belong to one genus. Rather high level of homology (62-63%) was found between Methylobacillus glycogenes ATCC 29475 and Pseudomonas insueta ATCC 21276 and strain G-10. The motile strain Methylophilus methylotrophus NCIB 10515 has a low homology (below 20%) to other of the studied obligate methylobacteria. Therefore, at least two genetically different genera of obligate methylobacteria can be distinguished, namely Methylophilus and Methylobacillus, the latter being represented by both motile and nonmotile forms.

  12. The Sit-and-Wait Hypothesis in Bacterial Pathogens: A Theoretical Study of Durability and Virulence

    Directory of Open Access Journals (Sweden)

    Liang Wang

    2017-11-01

    Full Text Available The intriguing sit-and-wait hypothesis predicts that bacterial durability in the external environment is positively correlated with their virulence. Since its first proposal in 1987, the hypothesis has been spurring debates in terms of its validity in the field of bacterial virulence. As a special case of the vector-borne transmission versus virulence tradeoff, where vector is now replaced by environmental longevity, there are only sporadic studies over the last three decades showing that environmental durability is possibly linked with virulence. However, no systematic study of these works is currently available and epidemiological analysis has not been updated for the sit-and-wait hypothesis since the publication of Walther and Ewald’s (2004 review. In this article, we put experimental evidence, epidemiological data and theoretical analysis together to support the sit-and-wait hypothesis. According to the epidemiological data in terms of gain and loss of virulence (+/- and durability (+/- phenotypes, we classify bacteria into four groups, which are: sit-and-wait pathogens (++, vector-borne pathogens (+-, obligate-intracellular bacteria (--, and free-living bacteria (-+. After that, we dive into the abundant bacterial proteomic data with the assistance of bioinformatics techniques in order to investigate the two factors at molecular level thanks to the fast development of high-throughput sequencing technology. Sequences of durability-related genes sourced from Gene Ontology and UniProt databases and virulence factors collected from Virulence Factor Database are used to search 20 corresponding bacterial proteomes in batch mode for homologous sequences via the HMMER software package. Statistical analysis only identified a modest, and not statistically significant correlation between mortality and survival time for eight non-vector-borne bacteria with sit-and-wait potentials. Meanwhile, through between-group comparisons, bacteria with higher

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-07-21

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

  14. AMPK in Pathogens

    OpenAIRE

    Mesquita, Inês Morais; Moreira, Diana; Marques, Belém Sampaio; Laforge, Mireille; Cordeiro-da-Silva, Anabela; Ludovico, Paula; Estaquier, Jérôme; Silvestre, Ricardo Jorge Leal

    2016-01-01

    During host–pathogen interactions, a complex web of events is crucial for the outcome of infection. Pathogen recognition triggers powerful cellular signaling events that is translated into the induction and maintenance of innate and adaptive host immunity against infection. In opposition, pathogens employ active mechanisms to manipulate host cell regulatory pathways toward their proliferation and survival. Among these, subversion of host cell energy metabolism by pathogens is currently recogn...

  15. Activation of Host IRE1α-Dependent Signaling Axis Contributes the Intracellular Parasitism of Brucella melitensis

    Directory of Open Access Journals (Sweden)

    Aseem Pandey

    2018-04-01

    Full Text Available Brucella spp. are intracellular vacuolar pathogens that causes brucellosis, a worldwide zoonosis of profound importance. We previously demonstrated that the activity of host unfolded protein response (UPR sensor IRE1α (inositol-requiring enzyme 1 and ER-associated autophagy confer susceptibility to Brucella melitensis and Brucella abortus intracellular replication. However, the mechanism by which host IRE1α regulates the pathogen intracellular lifestyle remains elusive. In this study, by employing a diverse array of molecular approaches, including biochemical analyses, fluorescence microscopy imaging, and infection assays using primary cells derived from Ern1 (encoding IRE1 conditional knockout mice, we address this gap in our understanding by demonstrating that a novel IRE1α to ULK1, an important component for autophagy initiation, signaling axis confers susceptibility to Brucella intracellular parasitism. Importantly, deletion or inactivation of key signaling components along this axis, including IRE1α, BAK/BAX, ASK1, and JNK as well as components of the host autophagy system ULK1, Atg9a, and Beclin 1, resulted in striking disruption of Brucella intracellular trafficking and replication. Host kinases in the IRE1α-ULK1 axis, including IRE1α, ASK1, JNK1, and/or AMPKα as well as ULK1, were also coordinately phosphorylated in an IRE1α-dependent fashion upon the pathogen infection. Taken together, our findings demonstrate that the IRE1α-ULK1 signaling axis is subverted by the bacterium to promote intracellular parasitism, and provide new insight into our understanding of the molecular mechanisms of intracellular lifestyle of Brucella.

  16. Global Redistributive Obligations in the Face of Severe Poverty

    DEFF Research Database (Denmark)

    Axelsen, David Vestergaard

    ? In the debate on global justice, a number of theorists argue that this discrepancy can indeed be justified (so-called anti-cosmopolitans). Thus, to bring us closer to answer regarding our redistributive obligations towards foreigners, I analyze and evaluate such arguments. My critical examination reveals...... comprehensive obligations to foreigners and compatriots simultaneously. Thus, even if we are duty-bound to redistribute comprehensively to compatriots, this does not entail that we could not also do so towards non-compatriots. Hence, their arguments are incomplete. Thirdly, I show that anti...

  17. The landing obligation in view of different management regimes

    DEFF Research Database (Denmark)

    Frost, Hans Staby; Hoff, Ayoe

    2017-01-01

    The European Union adopted a landing obligation in 2015 implying that all catches of fish subject to quota management must be landed. We compare and contrast the economic consequences for fisheries of the landing obligation in view of the management system on which it is super-imposed. Four types...... the strongest influence on both industry profitability and catch of unwanted species in the case of management with shared non-transferable quotas. In addition, the move from management with shared quotas to individual transferable quotas (ITQ) increases industry profitability and reduces unwanted catches...

  18. Glutathione provides a source of cysteine essential for intracellular multiplication of Francisella tularensis.

    Directory of Open Access Journals (Sweden)

    Khaled Alkhuder

    2009-01-01

    Full Text Available Francisella tularensis is a highly infectious bacterium causing the zoonotic disease tularemia. Its ability to multiply and survive in macrophages is critical for its virulence. By screening a bank of HimarFT transposon mutants of the F. tularensis live vaccine strain (LVS to isolate intracellular growth-deficient mutants, we selected one mutant in a gene encoding a putative gamma-glutamyl transpeptidase (GGT. This gene (FTL_0766 was hence designated ggt. The mutant strain showed impaired intracellular multiplication and was strongly attenuated for virulence in mice. Here we present evidence that the GGT activity of F. tularensis allows utilization of glutathione (GSH, gamma-glutamyl-cysteinyl-glycine and gamma-glutamyl-cysteine dipeptide as cysteine sources to ensure intracellular growth. This is the first demonstration of the essential role of a nutrient acquisition system in the intracellular multiplication of F. tularensis. GSH is the most abundant source of cysteine in the host cytosol. Thus, the capacity this intracellular bacterial pathogen has evolved to utilize the available GSH, as a source of cysteine in the host cytosol, constitutes a paradigm of bacteria-host adaptation.

  19. Activation of a Neospora caninum EGFR-Like Kinase Facilitates Intracellular Parasite Proliferation

    Directory of Open Access Journals (Sweden)

    Xiaoxia Jin

    2017-10-01

    Full Text Available The Apicomplexan parasite Neospora caninum, an obligate intracellular protozoan, causes serious diseases in a number of mammalian species, especially in cattle. Infection with N. caninum is associated with abortions in both dairy and beef cattle worldwide which have a major economic impact on the cattle industry. However, the mechanism by which N. caninum proliferates within host cells is poorly understood. Epidermal growth factor receptor (EGFR is a protein kinase ubiquitously expressed, present on cell surfaces in numerous species, which has been confirmed to be essential in signal transduction involved in cell growth, proliferation, survival, and many other intracellular processes. However, the presence of EGFR in N. caninum and its role in N. caninum proliferation remain unclear. In the present study, we identified a putative EGFR-like kinase in N. caninum, which could be activated in tachyzoites by infection or treatment with rNcMIC3 [containing four epidermal growth factor (EGF domains] or human EGF. Blockade of EGFR-like in tachyzoites by AG1478 significantly reduced parasite proliferation in host cells. Our data suggested that the activation of tachyzoite EGFR-like might facilitate the intracellular proliferation of N. caninum.

  20. Viral evasion of intracellular DNA and RNA sensing

    Science.gov (United States)

    Chan, Ying Kai; Gack, Michaela U.

    2016-01-01

    The co-evolution of viruses with their hosts has led to the emergence of viral pathogens that are adept at evading or actively suppressing host immunity. Pattern recognition receptors (PRRs) are key components of antiviral immunity that detect conserved molecular features of viral pathogens and initiate signalling that results in the expression of antiviral genes. In this Review, we discuss the strategies that viruses use to escape immune surveillance by key intracellular sensors of viral RNA or DNA, with a focus on RIG-I-like receptors (RLRs), cyclic GMP–AMP synthase (cGAS) and interferon-γ (IFNγ)-inducible protein 16 (IFI16). Such viral strategies include the sequestration or modification of viral nucleic acids, interference with specific post-translational modifications of PRRs or their adaptor proteins, the degradation or cleavage of PRRs or their adaptors, and the sequestration or relocalization of PRRs. An understanding of viral immune-evasion mechanisms at the molecular level may guide the development of vaccines and antivirals. PMID:27174148

  1. Osmoadaptative Strategy and Its Molecular Signature in Obligately Halophilic Heterotrophic Protists.

    Science.gov (United States)

    Harding, Tommy; Brown, Matthew W; Simpson, Alastair G B; Roger, Andrew J

    2016-08-03

    Halophilic microbes living in hypersaline environments must counteract the detrimental effects of low water activity and salt interference. Some halophilic prokaryotes equilibrate their intracellular osmotic strength with the extracellular milieu by importing inorganic solutes, mainly potassium. These "salt-in" organisms characteristically have proteins that are highly enriched with acidic and hydrophilic residues. In contrast, "salt-out" halophiles accumulate large amounts of organic solutes like amino acids, sugars and polyols, and lack a strong signature of halophilicity in the amino acid composition of cytoplasmic proteins. Studies to date have examined halophilic prokaryotes, yeasts, or algae, thus virtually nothing is known about the molecular adaptations of the other eukaryotic microbes, that is, heterotrophic protists (protozoa), that also thrive in hypersaline habitats. We conducted transcriptomic investigations to unravel the molecular adaptations of two obligately halophilic protists, Halocafeteria seosinensis and Pharyngomonas kirbyi Their predicted cytoplasmic proteomes showed increased hydrophilicity compared with marine protists. Furthermore, analysis of reconstructed ancestral sequences suggested that, relative to mesophiles, proteins in halophilic protists have undergone fewer substitutions from hydrophilic to hydrophobic residues since divergence from their closest relatives. These results suggest that these halophilic protists have a higher intracellular salt content than marine protists. However, absence of the acidic signature of salt-in microbes suggests that Haloc. seosinensis and P. kirbyi utilize organic osmolytes to maintain osmotic equilibrium. We detected increased expression of enzymes involved in synthesis and transport of organic osmolytes, namely hydroxyectoine and myo-inositol, at maximal salt concentration for growth in Haloc. seosinensis, suggesting possible candidates for these inferred organic osmolytes. © The Author 2016

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

    Science.gov (United States)

    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.

  3. 22 CFR 211.5 - Obligations of cooperating sponsor.

    Science.gov (United States)

    2010-04-01

    ... USE IN DISASTER RELIEF, ECONOMIC DEVELOPMENT AND OTHER ASSISTANCE § 211.5 Obligations of cooperating... of books and records maintained by recipient agencies that receive monetized proceeds and/or program..., reported and accounted for as provided in this Regulation, with special reference to paragraphs (k) and (l...

  4. 25 CFR 226.9 - Rental and drilling obligations.

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Rental and drilling obligations. 226.9 Section 226.9... RESERVATION LANDS FOR OIL AND GAS MINING Leasing Procedure, Rental and Royalty § 226.9 Rental and drilling... in the lease terms, or 12 months from the date the Superintendent consents to drilling on any...

  5. 22 CFR 231.07 - Fiscal Agent obligations.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Fiscal 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 108-11-STANDARD TERMS AND...

  6. Assignments of rights and obligations under a gas sales contract

    International Nuclear Information System (INIS)

    Kowch, J.R.M.

    1996-01-01

    A general overview of the principles of assignment in a gas sales contract was presented. Assignment is a process wherein the rights or obligations under a contract are transferred from one of the contracting parties to a third party. It is, in other words, the introduction of a new party to the original contractual relationship. Under the rights and obligations of a gas sales contract, the most important right of the seller is to have its gas taken and to be paid. Likewise, the most important obligation of the buyer is to take the gas and pay for it. An assignment by either party has the potential to alter the original expectations of the parties or the basis of which they committed to the contract in the first place. Prior to deregulation and unbundling initiatives, gas sellers and buyers could enter a 20 year sales contract and deal exclusively with each other over the entire 20 year term. Since deregulation, there are more players, and a higher level of corporate acquisitions, divestitures, rationalizations, and restructuring. Today, there are greater chances than ever before that the original party to a contract may change, or that certain rights and obligations may be assigned to a third party and affect the expectations under the contract

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

    Science.gov (United States)

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

    2008-11-01

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

  8. 34 CFR 75.707 - When obligations are made.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false When obligations are made. 75.707 Section 75.707 Education Office of the Secretary, Department of Education DIRECT GRANT PROGRAMS What Are the Administrative... services. (f) Travel When the travel is taken. (g) Rental of real or personal property When the grantee...

  9. 34 CFR 76.707 - When obligations are made.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false When obligations are made. 76.707 Section 76.707 Education Office of the Secretary, Department of Education STATE-ADMINISTERED PROGRAMS What Are the... subgrantee receives the services. (f) Travel When the travel is taken. (g) Rental of real or personal...

  10. Obama states obligation to act on climate change

    Science.gov (United States)

    Showstack, Randy

    2012-11-01

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

  11. 34 CFR 686.43 - Obligation to repay the grant.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false Obligation to repay the grant. 686.43 Section 686.43 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION TEACHER EDUCATION ASSISTANCE FOR COLLEGE AND HIGHER EDUCATION (TEACH...

  12. Political Obligation, Dirty Hands and Torture; A Moral Evaluation ...

    African Journals Online (AJOL)

    Political Obligation, Dirty Hands and Torture; A Moral Evaluation. H van Erp. Abstract. The example of a political leader who has to decide whether he would allow the torture of a suspect in order to get information about a ticking bomb has become notorious in ethical discussions concerning the tension between moral ...

  13. Life-Long Learning and Social Responsibility Obligations

    Science.gov (United States)

    Mayes, Robin

    2013-01-01

    The literature affirms that widespread lapses in corporate social responsibility obligations (unethical behaviors) have periodically brought about extensive forfeitures of economic wealth and countless job losses leaving the world economy in recession or depression. Put forth as a resolution to unemployment issues the academic literature champions…

  14. 14 CFR 272.8 - Obligation to continue service.

    Science.gov (United States)

    2010-01-01

    ... PROCEEDINGS) ECONOMIC REGULATIONS ESSENTIAL AIR SERVICE TO THE FREELY ASSOCIATED STATES § 272.8 Obligation to... eligible Freely Associated State place below the level of essential air service to such place, whether or not the Department has previously determined the level of essential air service to such place, the...

  15. Should Social Value Obligations be Local or Global?

    Science.gov (United States)

    Nayak, Rahul; Shah, Seema K

    2017-02-01

    According to prominent bioethics scholars and international guidelines, researchers and sponsors have obligations to ensure that the products of their research are reasonably available to research participants and their communities. In other words, the claim is that research is unethical unless it has local social value. In this article, we argue that the existing conception of reasonable availability should be replaced with a social value obligation that extends to the global poor (and not just research participants and host communities). To the extent the social value requirement has been understood as geographically constrained to the communities that host research and the countries that can afford the products of research, it has neglected to include the global poor as members of the relevant society. We argue that a new conception of social value obligations is needed for two reasons. First, duties of global beneficence give reason for researchers, sponsors, and institutions to take steps to make their products more widely accessible. Second, public commitments made by many institutions acknowledge and engender responsibilities to make the products of research more accessible to the global poor. Future research is needed to help researchers and sponsors discharge these obligations in ways that unlock their full potential. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  16. 13 CFR 500.213 - Termination of obligations.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Termination of obligations. 500.213 Section 500.213 Business Credit and Assistance EMERGENCY OIL AND GAS GUARANTEED LOAN BOARD... the Application, the Guarantee or the Loan Documents; (5) A Lender fails to make a demand for payment...

  17. Family Obligations in Micronesian Cultures: Implications for Educators

    Science.gov (United States)

    Ratliffe, Katherine T.

    2010-01-01

    Micronesian people, a new group of immigrants to the USA, have a strong system of responsibilities to family members that guides their priorities and actions. When family obligations clash with school priorities, conflicts can occur. I interviewed 26 adults to learn about the relationships and responsibilities of family members to each other in…

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

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Assistance in determining your obligations. 711.4 Section 711.4 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE CHEMICAL WEAPONS CONVENTION REGULATIONS...

  19. 31 CFR 223.18 - Performance of agency obligations.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Performance of agency obligations. 223.18 Section 223.18 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) FISCAL SERVICE, DEPARTMENT OF THE TREASURY FINANCIAL MANAGEMENT SERVICE SURETY COMPANIES DOING BUSINESS...

  20. Short communications : Are wild African lungfish obligate air ...

    African Journals Online (AJOL)

    Laboratory studies have resulted in classification of the marbled African lungfish, Protopterus aethiopicus, as an obligate air-breather. However, there have been no investigations of the extent of dependence on aerial respiration by this species in the wild. We used radio telemetry to obtain quantitative information on the ...

  1. Filial obligations today : moral practice, perception and ethical theory

    NARCIS (Netherlands)

    Stuifbergen, M.C.

    2011-01-01

    This thesis is about the meaning of filial obligations in Dutch society today. The thesis consists of a general introduction, two quantitative sociological studies, two qualitative studies, an ethical analysis and a general discussion. In the introduction, the background for the research questions

  2. 45 CFR 1226.13 - Obligations of sponsors.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Obligations of sponsors. 1226.13 Section 1226.13 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE PROHIBITIONS ON ELECTORAL AND LOBBYING ACTIVITIES Sponsor Employee Activities § 1226.13...

  3. Novation as a method of termination of obligations

    Directory of Open Access Journals (Sweden)

    Perović Marko

    2017-01-01

    Full Text Available The paper presents an analysis of the issue of novation in contract law. Novation is a contract between the creditor and debtor in order to replace its existing obligation with a new one. Unlike the other methods of termination of obligations (e.g. fulfillment, compensation, remission of debt, novation extinguishes existing contractual relationship between the creditor and the debtor, so that among them arise a new contractual relationship, which in relation to the previous one, differs on the case or legal basis. In most of the modern codifications of civil law, novation obtained a particular use in relation to the classical Roman law, which included a change of persons in obligations. In Serbian law, novation also has took the particular use and it takes an important place among many other termination methods of obligations. The analysis made in this paper, focused to the theoretical arguments and practical significance of the novation, brings the author to the conclusions and recommendations relevant to the novation in the theory and practices of contract law.

  4. \\"Forgotten\\" Humanitarian Obligations: The case of the Saharawi ...

    African Journals Online (AJOL)

    ... lay at the bar of international justice to call the international community to account for failures of performance on humanitarian obligations. It is their case that I take up here, as a problem of ethics in international affairs, as the minimum of a philosopher's recompense owed this people today. African Studies Monograph Vol.

  5. Investigating Internalization and Intracellular Trafficking of GPCRs

    DEFF Research Database (Denmark)

    Foster, Simon R; Bräuner-Osborne, Hans

    2017-01-01

    for signal transduction. One of the major mechanisms for GPCR regulation involves their endocytic trafficking, which serves to internalize the receptors from the plasma membrane and thereby attenuate G protein-dependent signaling. However, there is accumulating evidence to suggest that GPCRs can signal...... independently of G proteins, as well as from intracellular compartments including endosomes. It is in this context that receptor internalization and intracellular trafficking have attracted renewed interest within the GPCR field. In this chapter, we will review the current understanding and methodologies...

  6. Diversity of extracellular proteins during the transition from the ‘proto-apicomplexan’ alveolates to the apicomplexan obligate parasites

    KAUST Repository

    Templeton, Thomas J.

    2015-11-20

    The recent completion of high-coverage draft genome sequences for several alveolate protozoans – namely, the chromerids, Chromera velia and Vitrella brassicaformis ; the perkinsid Perkinsus marinus ; the apicomplexan, Gregarina niphandrodes , as well as high coverage transcriptome sequence information for several colpodellids, allows for new genome-scale comparisons across a rich landscape of apicomplexans and other alveolates. Genome annotations can now be used to help interpret fine ultrastructure and cell biology, and guide new studies to describe a variety of alveolate life strategies, such as symbiosis or free living, predation, and obligate intracellular parasitism, as well to provide foundations to dissect the evolutionary transitions between these niches. This review focuses on the attempt to identify extracellular proteins which might mediate the physical interface of cell–cell interactions within the above life strategies, aided by annotation of the repertoires of predicted surface and secreted proteins encoded within alveolate genomes. In particular, we discuss what descriptions of the predicted extracellular proteomes reveal regarding a hypothetical last common ancestor of a pre-apicomplexan alveolate – guided by ultrastructure, life strategies and phylogenetic relationships – in an attempt to understand the evolution of obligate parasitism in apicomplexans.

  7. Diversity of extracellular proteins during the transition from the ‘proto-apicomplexan’ alveolates to the apicomplexan obligate parasites

    KAUST Repository

    Templeton, Thomas J.; Pain, Arnab

    2015-01-01

    The recent completion of high-coverage draft genome sequences for several alveolate protozoans – namely, the chromerids, Chromera velia and Vitrella brassicaformis ; the perkinsid Perkinsus marinus ; the apicomplexan, Gregarina niphandrodes , as well as high coverage transcriptome sequence information for several colpodellids, allows for new genome-scale comparisons across a rich landscape of apicomplexans and other alveolates. Genome annotations can now be used to help interpret fine ultrastructure and cell biology, and guide new studies to describe a variety of alveolate life strategies, such as symbiosis or free living, predation, and obligate intracellular parasitism, as well to provide foundations to dissect the evolutionary transitions between these niches. This review focuses on the attempt to identify extracellular proteins which might mediate the physical interface of cell–cell interactions within the above life strategies, aided by annotation of the repertoires of predicted surface and secreted proteins encoded within alveolate genomes. In particular, we discuss what descriptions of the predicted extracellular proteomes reveal regarding a hypothetical last common ancestor of a pre-apicomplexan alveolate – guided by ultrastructure, life strategies and phylogenetic relationships – in an attempt to understand the evolution of obligate parasitism in apicomplexans.

  8. Cationic polymers for intracellular delivery of proteins

    NARCIS (Netherlands)

    Coué, G.M.J.P.C.; Engbersen, Johannes F.J.; Samal, Sangram; Dubruel, Peter

    2015-01-01

    Many therapeutic proteins exert their pharmaceutical action inside the cytoplasm or onto individual organelles inside the cell. Intracellular protein delivery is considered to be the most direct, fastest and safest approach for curing gene-deficiency diseases, enhancing vaccination and triggering

  9. Molecular detection and characterization of sustainable intracellular ...

    African Journals Online (AJOL)

    3Centre for Biopolymer and Bio-Molecular Research, Athlone College of Technology, Republic of Ireland. ... cells was associated with the elongation of micro-villar extension that ... Keywords: Intracellular contaminants, cell cultures, bacteria culture, pre-clinical studies. ... production work involving culture technology.

  10. Spatial Cytoskeleton Organization Supports Targeted Intracellular Transport

    Science.gov (United States)

    Hafner, Anne E.; Rieger, Heiko

    2018-03-01

    The efficiency of intracellular cargo transport from specific source to target locations is strongly dependent upon molecular motor-assisted motion along the cytoskeleton. Radial transport along microtubules and lateral transport along the filaments of the actin cortex underneath the cell membrane are characteristic for cells with a centrosome. The interplay between the specific cytoskeleton organization and the motor performance realizes a spatially inhomogeneous intermittent search strategy. In order to analyze the efficiency of such intracellular search strategies we formulate a random velocity model with intermittent arrest states. We evaluate efficiency in terms of mean first passage times for three different, frequently encountered intracellular transport tasks: i) the narrow escape problem, which emerges during cargo transport to a synapse or other specific region of the cell membrane, ii) the reaction problem, which considers the binding time of two particles within the cell, and iii) the reaction-escape problem, which arises when cargo must be released at a synapse only after pairing with another particle. Our results indicate that cells are able to realize efficient search strategies for various intracellular transport tasks economically through a spatial cytoskeleton organization that involves only a narrow actin cortex rather than a cell body filled with randomly oriented actin filaments.

  11. Biological synthesis and characterization of intracellular gold ...

    Indian Academy of Sciences (India)

    In the present study, Aspergillus fumigatus was used for the intracellular synthesis of gold nanoparticles. Stable nanoparticles were produced when an aqueous solution of chloroauric acid (HAuCl4) was reduced by A. fumigatus biomass as the reducing agent. Production of nanoparticles was confirmed by the colour ...

  12. Porphyromonas gingivalis evasion of autophagy and intracellular killing by human myeloid dendritic cells involves DC-SIGN-TLR2 crosstalk.

    Science.gov (United States)

    El-Awady, Ahmed R; Miles, Brodie; Scisci, Elizabeth; Kurago, Zoya B; Palani, Chithra D; Arce, Roger M; Waller, Jennifer L; Genco, Caroline A; Slocum, Connie; Manning, Matthew; Schoenlein, Patricia V; Cutler, Christopher W

    2015-02-01

    Signaling via pattern recognition receptors (PRRs) expressed on professional antigen presenting cells, such as dendritic cells (DCs), is crucial to the fate of engulfed microbes. Among the many PRRs expressed by DCs are Toll-like receptors (TLRs) and C-type lectins such as DC-SIGN. DC-SIGN is targeted by several major human pathogens for immune-evasion, although its role in intracellular routing of pathogens to autophagosomes is poorly understood. Here we examined the role of DC-SIGN and TLRs in evasion of autophagy and survival of Porphyromonas gingivalis in human monocyte-derived DCs (MoDCs). We employed a panel of P. gingivalis isogenic fimbriae deficient strains with defined defects in Mfa-1 fimbriae, a DC-SIGN ligand, and FimA fimbriae, a TLR2 agonist. Our results show that DC-SIGN dependent uptake of Mfa1+P. gingivalis strains by MoDCs resulted in lower intracellular killing and higher intracellular content of P. gingivalis. Moreover, Mfa1+P. gingivalis was mostly contained within single membrane vesicles, where it survived intracellularly. Survival was decreased by activation of TLR2 and/or autophagy. Mfa1+P. gingivalis strain did not induce significant levels of Rab5, LC3-II, and LAMP1. In contrast, P. gingivalis uptake through a DC-SIGN independent manner was associated with early endosomal routing through Rab5, increased LC3-II and LAMP-1, as well as the formation of double membrane intracellular phagophores, a characteristic feature of autophagy. These results suggest that selective engagement of DC-SIGN by Mfa-1+P. gingivalis promotes evasion of antibacterial autophagy and lysosome fusion, resulting in intracellular persistence in myeloid DCs; however TLR2 activation can overcome autophagy evasion and pathogen persistence in DCs.

  13. Optimizing Nanoelectrode Arrays for Scalable Intracellular Electrophysiology.

    Science.gov (United States)

    Abbott, Jeffrey; Ye, Tianyang; Ham, Donhee; Park, Hongkun

    2018-03-20

    Electrode technology for electrophysiology has a long history of innovation, with some decisive steps including the development of the voltage-clamp measurement technique by Hodgkin and Huxley in the 1940s and the invention of the patch clamp electrode by Neher and Sakmann in the 1970s. The high-precision intracellular recording enabled by the patch clamp electrode has since been a gold standard in studying the fundamental cellular processes underlying the electrical activities of neurons and other excitable cells. One logical next step would then be to parallelize these intracellular electrodes, since simultaneous intracellular recording from a large number of cells will benefit the study of complex neuronal networks and will increase the throughput of electrophysiological screening from basic neurobiology laboratories to the pharmaceutical industry. Patch clamp electrodes, however, are not built for parallelization; as for now, only ∼10 patch measurements in parallel are possible. It has long been envisioned that nanoscale electrodes may help meet this challenge. First, nanoscale electrodes were shown to enable intracellular access. Second, because their size scale is within the normal reach of the standard top-down fabrication, the nanoelectrodes can be scaled into a large array for parallelization. Third, such a nanoelectrode array can be monolithically integrated with complementary metal-oxide semiconductor (CMOS) electronics to facilitate the large array operation and the recording of the signals from a massive number of cells. These are some of the central ideas that have motivated the research activity into nanoelectrode electrophysiology, and these past years have seen fruitful developments. This Account aims to synthesize these findings so as to provide a useful reference. Summing up from the recent studies, we will first elucidate the morphology and associated electrical properties of the interface between a nanoelectrode and a cellular membrane

  14. 78 FR 46418 - Proposed Information Collection (Obligation To Report Factors Affecting Entitlement) Activity...

    Science.gov (United States)

    2013-07-31

    ... (Obligation To Report Factors Affecting Entitlement) Activity; Comment Request AGENCY: Veterans Benefits... use of other forms of information technology. Title: Obligation to Report Factors Affecting... entitlement factors. Individual factors such as income, marital status, and the beneficiary's number of...

  15. Exploring NAD+ metabolism in host-pathogen interactions.

    Science.gov (United States)

    Mesquita, Inês; Varela, Patrícia; Belinha, Ana; Gaifem, Joana; Laforge, Mireille; Vergnes, Baptiste; Estaquier, Jérôme; Silvestre, Ricardo

    2016-03-01

    Nicotinamide adenine dinucleotide (NAD(+)) is a vital molecule found in all living cells. NAD(+) intracellular levels are dictated by its synthesis, using the de novo and/or salvage pathway, and through its catabolic use as co-enzyme or co-substrate. The regulation of NAD(+) metabolism has proven to be an adequate drug target for several diseases, including cancer, neurodegenerative or inflammatory diseases. Increasing interest has been given to NAD(+) metabolism during innate and adaptive immune responses suggesting that its modulation could also be relevant during host-pathogen interactions. While the maintenance of NAD(+) homeostatic levels assures an adequate environment for host cell survival and proliferation, fluctuations in NAD(+) or biosynthetic precursors bioavailability have been described during host-pathogen interactions, which will interfere with pathogen persistence or clearance. Here, we review the double-edged sword of NAD(+) metabolism during host-pathogen interactions emphasizing its potential for treatment of infectious diseases.

  16. Pathogenic adaptations to host-derived antibacterial copper

    Science.gov (United States)

    Chaturvedi, Kaveri S.; Henderson, Jeffrey P.

    2014-01-01

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

  17. Profiling of Intracellular Metabolites: An Approach to Understanding the Characteristic Physiology of Mycobacterium leprae.

    Science.gov (United States)

    Miyamoto, Yuji; Mukai, Tetsu; Matsuoka, Masanori; Kai, Masanori; Maeda, Yumi; Makino, Masahiko

    2016-08-01

    Mycobacterium leprae is the causative agent of leprosy and also known to possess unique features such as inability to proliferate in vitro. Among the cellular components of M. leprae, various glycolipids present on the cell envelope are well characterized and some of them are identified to be pathogenic factors responsible for intracellular survival in host cells, while other intracellular metabolites, assumed to be associated with basic physiological feature, remain largely unknown. In the present study, to elucidate the comprehensive profile of intracellular metabolites, we performed the capillary electrophoresis-mass spectrometry (CE-MS) analysis on M. leprae and compared to that of M. bovis BCG. Interestingly, comparison of these two profiles showed that, in M. leprae, amino acids and their derivatives are significantly accumulated, but most of intermediates related to central carbon metabolism markedly decreased, implying that M. leprae possess unique metabolic features. The present study is the first report demonstrating the unique profiles of M. leprae metabolites and these insights might contribute to understanding undefined metabolism of M. leprae as well as pathogenic characteristics related to the manifestation of the disease.

  18. Induction of a stringent metabolic response in intracellular stages of Leishmania mexicana leads to increased dependence on mitochondrial metabolism.

    Directory of Open Access Journals (Sweden)

    Eleanor C Saunders

    2014-01-01

    Full Text Available Leishmania parasites alternate between extracellular promastigote stages in the insect vector and an obligate intracellular amastigote stage that proliferates within the phagolysosomal compartment of macrophages in the mammalian host. Most enzymes involved in Leishmania central carbon metabolism are constitutively expressed and stage-specific changes in energy metabolism remain poorly defined. Using (13C-stable isotope resolved metabolomics and (2H2O labelling, we show that amastigote differentiation is associated with reduction in growth rate and induction of a distinct stringent metabolic state. This state is characterized by a global decrease in the uptake and utilization of glucose and amino acids, a reduced secretion of organic acids and increased fatty acid β-oxidation. Isotopomer analysis showed that catabolism of hexose and fatty acids provide C4 dicarboxylic acids (succinate/malate and acetyl-CoA for the synthesis of glutamate via a compartmentalized mitochondrial tricarboxylic acid (TCA cycle. In vitro cultivated and intracellular amastigotes are acutely sensitive to inhibitors of mitochondrial aconitase and glutamine synthetase, indicating that these anabolic pathways are essential for intracellular growth and virulence. Lesion-derived amastigotes exhibit a similar metabolism to in vitro differentiated amastigotes, indicating that this stringent response is coupled to differentiation signals rather than exogenous nutrient levels. Induction of a stringent metabolic response may facilitate amastigote survival in a nutrient-poor intracellular niche and underlie the increased dependence of this stage on hexose and mitochondrial metabolism.

  19. 24 CFR 206.131 - Contract rights and obligations for mortgages on individual dwelling units in a condominium.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Contract rights and obligations for... MORTGAGE INSURANCE Contract Rights and Obligations Condominiums § 206.131 Contract rights and obligations...] Termination of Insurance Contract ...

  20. The sunflower downy mildew pathogen Plasmopara halstedii.

    Science.gov (United States)

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

    2015-02-01

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

  1. To what do we have moral obligations and why? II.

    Science.gov (United States)

    Gillon, R

    1985-06-08

    Following up on his 1 June 1985 article on moral obligations to living human beings versus other sentient beings, Gillon focuses on arguments for and against prohuman "speciesism," the claim that "viability" is a justifiable criterion for differentiating between humans that may be killed and those that may not, and claims that "personhood" is a morally relevant differentiating concept. He discusses the positions taken by Peter Singer and Dame Mary Warnock on "speciesism," and the theories of such philosphers as John Locke, Immanuel Kant, and Michael Tooley regarding the essence of personhood. He sees no solid basis for grounding the scope of moral obligations on simple sentience, membership in the human species, or technical differentia such as viability, and concludes that medical ethics still suffers from the lack of an adequate theory on which to base a right to life.

  2. Genetic Information, the Principle of Rescue, and Special Obligations.

    Science.gov (United States)

    Liao, S Matthew; Mackenzie, Jordan

    2018-05-01

    In "Genetic Privacy, Disease Prevention, and the Principle of Rescue," Madison Kilbride argues that patients have a duty to warn biological family members about clinically actionable adverse genetic findings. The duty does not stem from the special obligations that we may have to family members, she argues, but rather follows from the principle of rescue, which she understands as the idea that one ought to prevent, reduce, or mitigate the risk of harm to another person when the expected harm is serious and the cost or risk to oneself is sufficiently moderate. We doubt, however, whether the principle of rescue can ground a duty to warn in the cases Kilbride envisages, and we suggest that Kilbride may have underappreciated the role that special obligations could play in generating a duty to warn family members. © 2018 The Hastings Center.

  3. Electricity generation sectors under purchase obligation: support arrangement analysis

    International Nuclear Information System (INIS)

    2013-04-01

    This report aims at assessing the operation of the support arrangement by which currently benefit some electricity production sectors in France (renewable energies, co-generation) with respect to the evolution of the energy mix within the frame of energy transition. Other support arrangements presently adopted in Europe are also addressed as lessons to be learned. Criteria are established for any support arrangement. The report presents the French and European context regarding such support arrangement with purchasing obligation, and addresses the future evolutions of the European Commission. It highlights challenges for the electric system and for the energy market (impact on investments, optimization of market operation), describes and assesses the French purchasing obligation arrangement, and describes and assesses other existing support arrangements

  4. Duty of care is underpinned by a range of obligations.

    Science.gov (United States)

    Griffith, Richard

    The courts have long established that nurses are in a duty situation and owe a duty of care to their patients (Kent v Griffiths [2001]). Traditionally, the profession set the standard of care and nurses were required to act in accordance with a practice accepted by a responsible body of their peers (Bolam v Friern HMC [1957]).The introduction of the Human Rights Act 1998 gave rise to a positive obligation on government to ensure that laws, policies and procedures are in place to protect violations of human rights. Nurses must now inform their practice with relevant statute law, common law and professional standards in order to properly discharge their duty of care. Richard Griffith considers the law that now underpins a nurse's duty of care and uses a recent report from the Health Service Ombudsman for England to illustrate the obligations that underpin the nurse-patient relationship.

  5. Controls Over Unliquidated Obligations in the Iraq Relief and Reconstruction Fund

    National Research Council Canada - National Science Library

    Bowen, Stuart W

    2007-01-01

    .... Funds no longer needed may be deobligated. The purpose of this audit was to determine the amount of IRRF unliquidated obligations retained by DoD, DoS, and USAID and whether those agencies have established adequate management controls over their unliquidated obligations. This audit focused on annual reviews of unliquidated obligations that agencies should have completed for fiscal year 2006.

  6. 21 CFR 312.52 - Transfer of obligations to a contract research organization.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Transfer of obligations to a contract research... and Investigators § 312.52 Transfer of obligations to a contract research organization. (a) A sponsor may transfer responsibility for any or all of the obligations set forth in this part to a contract...

  7. Obligation de rendre compte | CRDI - Centre de recherches pour le ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les mécanismes qui appuient l'obligation de rendre compte, comme les comités spéciaux, les unités organisationnelles spécialisées et les pratiques administratives quotidiennes, englobent la gestion du risque, les audits, les évaluations, l'accès à l'information, la production de rapports à l'intention du Parlement et la ...

  8. The pipeline service obligation under changing LDC purchasing practices

    International Nuclear Information System (INIS)

    Neff, S.J.

    1990-01-01

    Historically, interstate natural gas pipelines served as aggregators and transporters of gas supplies from the producing fields to the city-gate. In turn, local distribution companies (LDCs) bought gas from pipelines at the city-gate under long-term sales contracts and resold the gas to retail customers. Once a pipeline/LDC sales relationship was established through a regulated certificate process, the LDC was assured of gas supply up to the level of its contract demand (CD) at just and reasonable rates until abandonment of the pipeline's sales service obligation was granted by the Federal Energy Regulatory Commission (FERC). During the years of regulated wellhead pricing and limited gas deliverability, pipelines signed long-term take-or-pay contracts with producers to induce them to develop and commit new gas supplies. Those supply cost obligations were reflected in tariff minimum bill provisions. For years, this pipeline/LDC arrangement was mutually beneficial and provided assured firm service. With the load diversity on large interstate pipeline systems and the make-up provisions under take-or-pay clauses, these gas purchase contracts provided supply reliability without negative economic consequence to the pipelines. Then, with the issuance of FERC Order Nos. 380, 436, and 500, LDCs' obligations to purchase gas from pipeline suppliers according to the terms of those long term sales agreements were irrevocably altered. The impacts of those long term sales agreements were irrevocably altered. The impacts of those orders the elimination of minimum bills and the advent of open access transportation caused a serious erosion of the mutual obligations between pipelines and their LDC customers. The result has been a significant loss of pipeline sales markets as LDC customers have chosen alternative supplied, often at the urging of state public utility commissions (PUCs) to lower short-term costs

  9. Salmonella Intracellular Lifestyles and Their Impact on Host-to-Host Transmission.

    Science.gov (United States)

    Pucciarelli, M Graciela; García-Del Portillo, Francisco

    2017-07-01

    More than a century ago, infections by Salmonella were already associated with foodborne enteric diseases with high morbidity in humans and cattle. Intestinal inflammation and diarrhea are hallmarks of infections caused by nontyphoidal Salmonella serovars, and these pathologies facilitate pathogen transmission to the environment. In those early times, physicians and microbiologists also realized that typhoid and paratyphoid fever caused by some Salmonella serovars could be transmitted by "carriers," individuals outwardly healthy or at most suffering from some minor chronic complaint. In his pioneering study of the nontyphoidal serovar Typhimurium in 1967, Takeuchi published the first images of intracellular bacteria enclosed by membrane-bound vacuoles in the initial stages of the intestinal epithelium penetration. These compartments, called Salmonella -containing vacuoles, are highly dynamic phagosomes with differing biogenesis depending on the host cell type. Single-cell studies involving real-time imaging and gene expression profiling, together with new approaches based on genetic reporters sensitive to growth rate, have uncovered unprecedented heterogeneous responses in intracellular bacteria. Subpopulations of intracellular bacteria displaying fast, reduced, or no growth, as well as cytosolic and intravacuolar bacteria, have been reported in both in vitro and in vivo infection models. Recent investigations, most of them focused on the serovar Typhimurium, point to the selection of persisting bacteria inside macrophages or following an autophagy attack in fibroblasts. Here, we discuss these heterogeneous intracellular lifestyles and speculate on how these disparate behaviors may impact host-to-host transmissibility of Salmonella serovars.

  10. MicroRNA-155 promotes autophagy to eliminate intracellular mycobacteria by targeting Rheb.

    Science.gov (United States)

    Wang, Jinli; Yang, Kun; Zhou, Lin; Minhaowu; Wu, Yongjian; Zhu, Min; Lai, Xiaomin; Chen, Tao; Feng, Lianqiang; Li, Meiyu; Huang, Chunyu; Zhong, Qiu; Huang, Xi

    2013-01-01

    Mycobacterium tuberculosis is a hard-to-eradicate intracellular pathogen that infects one-third of the global population. It can live within macrophages owning to its ability to arrest phagolysosome biogenesis. Autophagy has recently been identified as an effective way to control the intracellular mycobacteria by enhancing phagosome maturation. In the present study, we demonstrate a novel role of miR-155 in regulating the autophagy-mediated anti-mycobacterial response. Both in vivo and in vitro studies showed that miR-155 expression was significantly enhanced after mycobacterial infection. Forced expression of miR-155 accelerated the autophagic response in macrophages, thus promoting the maturation of mycobacterial phagosomes and decreasing the survival rate of intracellular mycobacteria, while transfection with miR-155 inhibitor increased mycobacterial survival. However, macrophage-mediated mycobacterial phagocytosis was not affected after miR-155 overexpression or inhibition. Furthermore, blocking autophagy with specific inhibitor 3-methyladenine or silencing of autophagy related gene 7 (Atg7) reduced the ability of miR-155 to promote autophagy and mycobacterial elimination. More importantly, our study demonstrated that miR-155 bound to the 3'-untranslated region of Ras homologue enriched in brain (Rheb), a negative regulator of autophagy, accelerated the process of autophagy and sequential killing of intracellular mycobacteria by suppressing Rheb expression. Our results reveal a novel role of miR-155 in regulating autophagy-mediated mycobacterial elimination by targeting Rheb, and provide potential targets for clinical treatment.

  11. MicroRNA-155 promotes autophagy to eliminate intracellular mycobacteria by targeting Rheb.

    Directory of Open Access Journals (Sweden)

    Jinli Wang

    Full Text Available Mycobacterium tuberculosis is a hard-to-eradicate intracellular pathogen that infects one-third of the global population. It can live within macrophages owning to its ability to arrest phagolysosome biogenesis. Autophagy has recently been identified as an effective way to control the intracellular mycobacteria by enhancing phagosome maturation. In the present study, we demonstrate a novel role of miR-155 in regulating the autophagy-mediated anti-mycobacterial response. Both in vivo and in vitro studies showed that miR-155 expression was significantly enhanced after mycobacterial infection. Forced expression of miR-155 accelerated the autophagic response in macrophages, thus promoting the maturation of mycobacterial phagosomes and decreasing the survival rate of intracellular mycobacteria, while transfection with miR-155 inhibitor increased mycobacterial survival. However, macrophage-mediated mycobacterial phagocytosis was not affected after miR-155 overexpression or inhibition. Furthermore, blocking autophagy with specific inhibitor 3-methyladenine or silencing of autophagy related gene 7 (Atg7 reduced the ability of miR-155 to promote autophagy and mycobacterial elimination. More importantly, our study demonstrated that miR-155 bound to the 3'-untranslated region of Ras homologue enriched in brain (Rheb, a negative regulator of autophagy, accelerated the process of autophagy and sequential killing of intracellular mycobacteria by suppressing Rheb expression. Our results reveal a novel role of miR-155 in regulating autophagy-mediated mycobacterial elimination by targeting Rheb, and provide potential targets for clinical treatment.

  12. A new type of intracellular retention signal identified in a pestivirus structural glycoprotein.

    Science.gov (United States)

    Burrack, Sandra; Aberle, Daniel; Bürck, Jochen; Ulrich, Anne S; Meyers, Gregor

    2012-08-01

    Sorting of membrane proteins into intracellular organelles is crucial for cell function. Viruses exploit intracellular transport and retention systems to concentrate envelope proteins at the site of virus budding. In pestiviruses, a group of important pathogens of pigs and ruminants closely related to human hepatitis C virus, the E(rns) protein translated from the viral RNA is secreted from the infected cells and found in the serum of infected animals. Secretion of the protein is regarded as crucial for its function as a viral virulence factor associated with its RNase activity. However, ∼95% of the E(rns) molecules are retained within the infected cell. Fusion of different E(rns) fragments to the C terminus of CD72 allowed identification of a retention signal within the C-terminal 65 aa of the viral protein. This C-terminal sequence represents its membrane anchor and folds into an amphipathic helix binding in-plane to the membrane surface. Residues L183, I190, and L208 are important for intracellular location of E(rns). Presentation of the retention signal on the cytoplasmic instead of the luminal face of the ER membrane in CD8α fusion proteins still led to retention. Thus, E(rns) contains in its C-terminal amphipathic helix an intracellular retention signal that is active on both faces of the membrane.

  13. The relationship between family obligation and religiosity on caregiving.

    Science.gov (United States)

    Epps, Fayron

    2014-01-01

    The purpose of this study was to examine the relationship between family obligation and religiosity on the positive appraisal of caregiving among African-American, Hispanic and non-Hispanic Caucasian family caregivers of older adults. Roy's adaptation model guided formulation of the aims and study design. A cross-sectional, correlational study design was employed to examine the relationship amongst variables for the family caregiver participants. Study participants (N = 69) completed a demographic tool and four instruments the: (1) Katz index, (2) obligation scale, (3) Duke University religion index, and (4) positive appraisal of care scale. There was a significant correlation between family obligation and positive appraisal of caregiving. However, there was no relationship between the family caregiver's religiosity and positive appraisal of caregiving overall. Demographic variables were also examined to show a higher marginal mean for Hispanic primary caregivers in relation to the positive appraisal of caregiving. Future studies should consider replicating these findings in a larger sample to provide health care professionals with substantial evidence to incorporate culturally sensitive interventions aimed at promoting positive outcomes and healthy family behaviors. Copyright © 2014 Mosby, Inc. All rights reserved.

  14. Yucca aloifolia (Asparagaceae) opts out of an obligate pollination mutualism.

    Science.gov (United States)

    Rentsch, Jeremy D; Leebens-Mack, Jim

    2014-12-01

    • According to Cope's 'law of the unspecialized' highly dependent species interactions are 'evolutionary dead ends,' prone to extinction because reversion to more generalist interactions is thought to be unlikely. Cases of extreme specialization, such as those seen between obligate mutualists, are cast as evolutionarily inescapable, inevitably leading to extinction rather than diversification of participating species. The pollination mutualism between Yucca plants and yucca moths (Tegeticula and Parategeticula) would seem to be locked into such an obligate mutualism. Yucca aloifolia populations, however, can produce large numbers of fruit lacking moth oviposition scars. Here, we investigate the pollination ecology of Y. aloifolia, in search of the non-moth pollination of a Yucca species.• We perform pollinator exclusion studies on Yucca aloifolia and a sympatric yucca species, Y. filamentosa. We then perform postvisit exclusion treatments, an analysis of dissected fruits, and a fluorescent dye transfer experiment.• As expected, Yucca filamentosa plants set fruit only when inflorescences were exposed to crepuscular and nocturnal pollinating yucca moths. In contrast, good fruit set was observed when pollinators were excluded from Y. aloifolia inflorescences from dusk to dawn, and no fruit set was observed when pollinators were excluded during the day. Follow up experiments indicated that European honeybees (Apis mellifera) were passively yet effectively pollinating Y. aloifolia flowers.• These results indicate that even highly specialized mutualisms may not be entirely obligate interactions or evolutionary dead ends. © 2014 Botanical Society of America, Inc.

  15. Conditions applying to Australian uranium exports - safeguards obligations under NPT

    International Nuclear Information System (INIS)

    Rotsey, W.B.

    1975-08-01

    The Australian Government's expressed desire to inhibit the spread of nuclear weapons and its wish to prevent Australia's uranium exports being used for manufacture of nuclear explosives are underwritten by Australia's formal international obligations. Australia is not free to export its material without paying due regard to supra-national requirements. This paper defines two safeguards regimes, one applying to countries such as Australia which are party to the Treaty on Non-Proliferation of Nuclear Weapons (NPT), the other to those which are not parties. The application of safeguards and the role of the International Atomic Energy Agency (IAEA) are briefly explained. Australia's obligations under the NPT and those stemming from specific undertakings to the IAEA are stated. The latter require Australia to ensure that Non-Nuclear Weapons States not party to the NPT give assurances that Australian uranium will not be used for the manufacture of nuclear explosives and that they will permit verification by the IAEA. These obligations give rise to a set of minimum conditions applying to exports of Australian uranium which vary according to the NPT status of the importing countries. (author)

  16. Kant's assessment of motivation in the fulfillment of social obligations.

    Science.gov (United States)

    Knupp, Jackie

    2006-01-01

    This paper explores the motivations of physicians who promote the health of their communities through the fulfillment of social obligations beyond the boundaries of their own patients. Based on the assumption that physicians do not have social obligations, this paper looks at the normative, motivational question, namely "How should physicians be motivated to fulfill social obligations?" The paper traces the Kantian view of morality and motivation. The distinctions between required, merely permissible, and forbidden actions is drawn. Furthermore, Kant's view that required actions done in accordance with duty are of no moral worth is critiqued from three stand points. First, it is argued that just because motivations outside of Kantian-based duty are not as good, it does not follow that these motivations are of no moral worth. Second, it is argued that there are some motivations behind required actions that are clearly better than other motivations. Third, it is argued that required actions done in accordance with duty are clearly better than those actions done without relevance to duty. The paper concludes that many required actions done in accordance with duty are performed from motivations that do have moral worth.

  17. AMPK in Pathogens.

    Science.gov (United States)

    Mesquita, Inês; Moreira, Diana; Sampaio-Marques, Belém; Laforge, Mireille; Cordeiro-da-Silva, Anabela; Ludovico, Paula; Estaquier, Jérôme; Silvestre, Ricardo

    2016-01-01

    During host-pathogen interactions, a complex web of events is crucial for the outcome of infection. Pathogen recognition triggers powerful cellular signaling events that is translated into the induction and maintenance of innate and adaptive host immunity against infection. In opposition, pathogens employ active mechanisms to manipulate host cell regulatory pathways toward their proliferation and survival. Among these, subversion of host cell energy metabolism by pathogens is currently recognized to play an important role in microbial growth and persistence. Extensive studies have documented the role of AMP-activated protein kinase (AMPK) signaling, a central cellular hub involved in the regulation of energy homeostasis, in host-pathogen interactions. Here, we highlight the most recent advances detailing how pathogens hijack cellular metabolism by suppressing or increasing the activity of the host energy sensor AMPK. We also address the role of lower eukaryote AMPK orthologues in the adaptive process to the host microenvironment and their contribution for pathogen survival, differentiation, and growth. Finally, we review the effects of pharmacological or genetic AMPK modulation on pathogen growth and persistence.

  18. Potatoes, pathogens and pests

    NARCIS (Netherlands)

    Lazebnik, Jenny

    2017-01-01

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

  19. Food-borne pathogens

    International Nuclear Information System (INIS)

    Niemand, J.G.

    1985-01-01

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

  20. Pathogen inactivation techniques.

    Science.gov (United States)

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

    2006-01-01

    The desire to rid the blood supply of pathogens of all types has led to the development of many technologies aimed at the same goal--eradication of the pathogen(s) without harming the blood cells or generating toxic chemical agents. This is a very ambitious goal, and one that has yet to be achieved. One approach is to shun the 'one size fits all' concept and to target pathogen-reduction agents at the Individual component types. This permits the development of technologies that might be compatible with, for example, plasma products but that would be cytocidal and thus incompatible with platelet concentrates or red blood cell units. The technologies to be discussed include solvent detergent and methylene blue treatments--designed to inactivate plasma components and derivatives; psoralens (S-59--amotosalen) designed to pathogen-reduce units of platelets; and two products aimed at red blood cells, S-303 (a Frale--frangible anchor-linker effector compound) and Inactine (a binary ethyleneimine). A final pathogen-reduction material that might actually allow one material to inactivate all three blood components--riboflavin (vitamin B2)--is also under development. The sites of action of the amotosalen (S-59), the S-303 Frale, Inactine, and riboflavin are all localized in the nucleic acid part of the pathogen. Solvent detergent materials act by dissolving the plasma envelope, thus compromising the integrity of the pathogen membrane and rendering it non-infectious. By disrupting the pathogen's ability to replicate or survive, its infectivity is removed. The degree to which bacteria and viruses are affected by a particular pathogen-reducing technology relates to its Gram-positive or Gram-negative status, to the sporulation characteristics for bacteria, and the presence of lipid or protein envelopes for viruses. Concerns related to photoproducts and other breakdown products of these technologies remain, and the toxicology of pathogen-reduction treatments is a major ongoing area

  1. Processes for managing pathogens.

    Science.gov (United States)

    Godfree, Alan; Farrell, Joseph

    2005-01-01

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

  2. Intracellular, genetic or congenital immunisation--transgenic approaches to increase disease resistance of farm animals.

    Science.gov (United States)

    Müller, M; Brem, G

    1996-01-26

    Novel approaches to modify disease resistance or susceptibility in livestock are justified not only by economical reasons and with respect to animal welfare but also by recent advancements in molecular genetics. The control or elimination of infectious pathogens in farm animals is historically achieved by the use of vaccines and drugs and by quarantine safeguards and eradication. Currently, research on the improvement of disease resistance based on nucleic acid technology focuses on two main issues: additive gene transfer and the development of nucleic acid vaccines. The strategies aim at the stable or transient expression of components known to influence non-specific or specific host defence mechanisms against infectious pathogens. Thus, candidates for gene transfer experiments include all genes inducing or conferring innate and acquired immunity as well as specific disease resistance genes. Referring to the site and mode of action and the source of the effective agent the strategies are termed 'intracellular', 'genetic' and 'congenital' immunisation. The targeted disruption (deletive gene transfer) of disease susceptibility genes awaits the establishment of totipotential embryonic cell lineages in farm animals. The cytokine network regulates cellular viability, growth and differentiation in physiological and pathophysiological states. The identification of the JAK-STAT pathway used by many cytokines for their intracellular signal propagation has provided not only new target molecules for modulating the immune response but will also permit the further elucidation of host-pathogen interactions and resistance mechanisms.

  3. Dynamics of gradient formation by intracellular shuttling

    Energy Technology Data Exchange (ETDEWEB)

    Berezhkovskii, Alexander M. [Mathematical and Statistical Computing Laboratory, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, Maryland 20892 (United States); Shvartsman, Stanislav Y. [Department of Chemical and Biological Engineering and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544 (United States)

    2015-08-21

    A number of important cellular functions rely on the formation of intracellular protein concentration gradients. Experimental studies discovered a number of mechanisms for the formation of such gradients. One of the mechanisms relies on the intracellular shuttling of a protein that interconverts between the two states with different diffusivities, under the action of two enzymes, one of which is localized to the plasma membrane, whereas the second is uniformly distributed in the cytoplasm. Recent work reported an analytical solution for the steady state gradient in this mechanism, obtained in the framework of a one-dimensional reaction-diffusion model. Here, we study the dynamics in this model and derive analytical expressions for the Laplace transforms of the time-dependent concentration profiles in terms of elementary transcendental functions. Inverting these transforms numerically, one can obtain time-dependent concentration profiles of the two forms of the protein.

  4. Leishmania hijacking of the macrophage intracellular compartments.

    Science.gov (United States)

    Liévin-Le Moal, Vanessa; Loiseau, Philippe M

    2016-02-01

    Leishmania spp., transmitted to humans by the bite of the sandfly vector, are responsible for the three major forms of leishmaniasis, cutaneous, diffuse mucocutaneous and visceral. Leishmania spp. interact with membrane receptors of neutrophils and macrophages. In macrophages, the parasite is internalized within a parasitophorous vacuole and engages in a particular intracellular lifestyle in which the flagellated, motile Leishmania promastigote metacyclic form differentiates into non-motile, metacyclic amastigote form. This phenomenon is induced by Leishmania-triggered events leading to the fusion of the parasitophorous vacuole with vesicular members of the host cell endocytic pathway including recycling endosomes, late endosomes and the endoplasmic reticulum. Maturation of the parasitophorous vacuole leads to the intracellular proliferation of the Leishmania amastigote forms by acquisition of host cell nutrients while escaping host defense responses. © 2015 FEBS.

  5. Reduction of intracellular glutathione content and radiosensitivity

    International Nuclear Information System (INIS)

    Vos, O.; Schans, G.P. van der; Roos-Verheij, W.S.D.

    1986-05-01

    The intracellular glutathione (GSH) content in HeLa, CHO and V79 cells was reduced by incubating the cells in growth medium containing buthionine sulfoximine (BSO) or diethyl maleate (DEM). Clonogenicity, single strand DNA breaks (ssb) and double strand DNA breaks (dsb) were used as criteria for radiation induced damage after X- or γ irradiation. In survival experiments DEM gave a slightly larger sensitization although it gave a smaller reduction of the intracellular GSH. In general, sensitization was larger for dsb than for ssb, also the reduction of the OER was generally larger for dsb than for ssb. This may be due to the higher dose rate in case of dsb experiments resulting in a higher rate of radiochemical oxygen consumption. In general, no effect was found on post-irradiation repair of ssb and dsb. (Auth.)

  6. Reduction of intracellular glutathione content and radiosensitivity

    International Nuclear Information System (INIS)

    Vos, O.; Schans, G.P. van der; Roos-Verheij, W.S.D.

    1986-01-01

    The intracellular glutathione (GSH) content of HeLa, CHO and V79 cells was reduced by incubating the cells in growth medium containing buthionine sulphoximine or diethyl maleate (DEM). Clonogenicity, single-strand DNA breaks (ssb) and double-strand DNA breaks (dsb) were used as criteria for radiation-induced damage after X- or γ-irradiation. In survival experiments, DEM gave a slightly larger sensitization although it gave a smaller reduction of the intracellular GSH. In general, sensitization was larger for dsb than for ssb, also the reduction of the o.e.r. was generally larger for dsb than for ssb. This may be due to the higher dose rate in case of dsb experiments resulting in a higher rate of radiochemical oxygen consumption. In general, no effect was found on post-irradiation repair of ssb and dsb. (author)

  7. Intracellular mechanisms of solar water disinfection

    Science.gov (United States)

    Castro-Alférez, María; Polo-López, María Inmaculada; Fernández-Ibáñez, Pilar

    2016-12-01

    Solar water disinfection (SODIS) is a zero-cost intervention measure to disinfect drinking water in areas of poor access to improved water sources, used by more than 6 million people in the world. The bactericidal action of solar radiation in water has been widely proven, nevertheless the causes for this remain still unclear. Scientific literature points out that generation of reactive oxygen species (ROS) inside microorganisms promoted by solar light absorption is the main reason. For the first time, this work reports on the experimental measurement of accumulated intracellular ROS in E. coli during solar irradiation. For this experimental achievement, a modified protocol based on the fluorescent probe dichlorodihydrofluorescein diacetate (DCFH-DA), widely used for oxidative stress in eukaryotic cells, has been tested and validated for E. coli. Our results demonstrate that ROS and their accumulated oxidative damages at intracellular level are key in solar water disinfection.

  8. Comparative genomics of transport proteins in probiotic and pathogenic Escherichia coli and Salmonella enterica strains.

    Science.gov (United States)

    Do, Jimmy; Zafar, Hassan; Saier, Milton H

    2017-06-01

    Escherichia coli is a genetically diverse species that can be pathogenic, probiotic, commensal, or a harmless laboratory strain. Pathogenic strains of E. coli cause urinary tract infections, diarrhea, hemorrhagic colitis, and pyelonephritis, while the two known probiotic E. coli strains combat inflammatory bowel disease and play a role in immunomodulation. Salmonella enterica, a close relative of E. coli, includes two important pathogenic serovars, Typhi and Typhimurium, causing typhoid fever and enterocolitis in humans, respectively, with the latter strain also causing a lethal typhoid fever-like disease in mice. In this study, we identify the transport systems and their substrates within seven E. coli strains: two probiotic strains, two extracellular pathogens, two intracellular pathogens, and K-12, as well as the two intracellular pathogenic S. enterica strains noted above. Transport systems characteristic of each probiotic or pathogenic species were thus identified, and the tabulated results obtained with all of these strains were compared. We found that the probiotic and pathogenic strains generally contain more iron-siderophore and sugar transporters than E. coli K-12. Pathogens have increased numbers of pore-forming toxins, protein secretion systems, decarboxylation-driven Na + exporters, electron flow-driven monovalent cation exporters, and putative transporters of unknown function compared to the probiotic strains. Both pathogens and probiotic strains encode metabolite transporters that reflect their intracellular versus extracellular environments. The results indicate that the probiotic strains live extracellularly. It seems that relatively few virulence factors can convert a beneficial or commensal microorganism into a pathogen. Taken together, the results reveal the distinguishing features of these strains and provide a starting point for future engineering of beneficial enteric bacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Development of growth rate measuring method for intracellular, parasitic acid-fast bacteria using radioisotopes

    International Nuclear Information System (INIS)

    Nakata, Noboru; Fukutomi, Yasuo

    1998-01-01

    To prevent and treat infections diseases caused by pathogenic acid-fast bacteria such as Mycobacterium leprae, Tubercle bacillus, it is important to elucidate the mechanisms of intracellular proliferations of these bacteria. This research project was started to make DNA library using a new constructed shuttle vector. Development of in vitro evaluation method for intracellular proliferation of mycobacterium and its transformed cells was attempted on the basis of Buddemeyer method. This method was able to precisely determine the metabolic activities as low as those in leprae and its modified method using 14 C-palmitic acid was highly sensitive and the results were obtainable in a shorter period. The generated CO 2 was satisfactorily absorbed into scintillator without using a filter paper. A new culture medium from which arginine, a NO-producing compound was eliminated was used to repress the sterilizing effects of NO, but the metabolic activities of leprae was not enhanced. (M.N.)

  10. Development of growth rate measuring method for intracellular, parasitic acid-fast bacteria using radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Nakata, Noboru; Fukutomi, Yasuo [National Inst. of Infectious Deseases, Tokyo (Japan)

    1998-02-01

    To prevent and treat infections diseases caused by pathogenic acid-fast bacteria such as Mycobacterium leprae, Tubercle bacillus, it is important to elucidate the mechanisms of intracellular proliferations of these bacteria. This research project was started to make DNA library using a new constructed shuttle vector. Development of in vitro evaluation method for intracellular proliferation of mycobacterium and its transformed cells was attempted on the basis of Buddemeyer method. This method was able to precisely determine the metabolic activities as low as those in leprae and its modified method using {sup 14}C-palmitic acid was highly sensitive and the results were obtainable in a shorter period. The generated CO{sub 2} was satisfactorily absorbed into scintillator without using a filter paper. A new culture medium from which arginine, a NO-producing compound was eliminated was used to repress the sterilizing effects of NO, but the metabolic activities of leprae was not enhanced. (M.N.)

  11. Intracellular serpins, firewalls and tissue necrosis.

    Science.gov (United States)

    Marciniak, Stefan J; Lomas, David A

    2008-02-01

    Luke and colleagues have recently attributed a new role to a member of the serpin superfamily of serine proteinase inhibitors. They have used Caenorhabditis elegans to show that an intracellular serpin is crucial for maintaining lysosomal integrity. We examine the role of this firewall in preventing necrosis and attempt to integrate this with current theories of stress-induced protein degradation. We discuss how mutant serpins cause disease either through polymerization or now, perhaps, by unleashing necrosis.

  12. Fluorescent nanoparticles for intracellular sensing: A review

    International Nuclear Information System (INIS)

    Ruedas-Rama, Maria J.; Walters, Jamie D.; Orte, Angel; Hall, Elizabeth A.H.

    2012-01-01

    Highlights: ► Analytical applications of fluorescent nanoparticles (NPs) in intracellular sensing. ► Critical review on performance of QDots, metal NPs, silica NPs, and polymer NPs. ► Highlighted potential of fluorescence lifetime imaging microscopy (FLIM). - Abstract: Fluorescent nanoparticles (NPs), including semiconductor NPs (Quantum Dots), metal NPs, silica NPs, polymer NPs, etc., have been a major focus of research and development during the past decade. The fluorescent nanoparticles show unique chemical and optical properties, such as brighter fluorescence, higher photostability and higher biocompatibility, compared to classical fluorescent organic dyes. Moreover, the nanoparticles can also act as multivalent scaffolds for the realization of supramolecular assemblies, since their high surface to volume ratio allow distinct spatial domains to be functionalized, which can provide a versatile synthetic platform for the implementation of different sensing schemes. Their excellent properties make them one of the most useful tools that chemistry has supplied to biomedical research, enabling the intracellular monitoring of many different species for medical and biological purposes. In this review, we focus on the developments and analytical applications of fluorescent nanoparticles in chemical and biological sensing within the intracellular environment. The review also points out the great potential of fluorescent NPs for fluorescence lifetime imaging microscopy (FLIM). Finally, we also give an overview of the current methods for delivering of fluorescent NPs into cells, where critically examine the benefits and liabilities of each strategy.

  13. Fluorescent nanoparticles for intracellular sensing: A review

    Energy Technology Data Exchange (ETDEWEB)

    Ruedas-Rama, Maria J., E-mail: mjruedas@ugr.esmailto [Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Campus Cartuja, 18071, Granada (Spain); Walters, Jamie D. [Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, UK CB2 1QT (United Kingdom); Orte, Angel [Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Campus Cartuja, 18071, Granada (Spain); Hall, Elizabeth A.H., E-mail: lisa.hall@biotech.cam.ac.uk [Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QT (United Kingdom)

    2012-11-02

    Highlights: Black-Right-Pointing-Pointer Analytical applications of fluorescent nanoparticles (NPs) in intracellular sensing. Black-Right-Pointing-Pointer Critical review on performance of QDots, metal NPs, silica NPs, and polymer NPs. Black-Right-Pointing-Pointer Highlighted potential of fluorescence lifetime imaging microscopy (FLIM). - Abstract: Fluorescent nanoparticles (NPs), including semiconductor NPs (Quantum Dots), metal NPs, silica NPs, polymer NPs, etc., have been a major focus of research and development during the past decade. The fluorescent nanoparticles show unique chemical and optical properties, such as brighter fluorescence, higher photostability and higher biocompatibility, compared to classical fluorescent organic dyes. Moreover, the nanoparticles can also act as multivalent scaffolds for the realization of supramolecular assemblies, since their high surface to volume ratio allow distinct spatial domains to be functionalized, which can provide a versatile synthetic platform for the implementation of different sensing schemes. Their excellent properties make them one of the most useful tools that chemistry has supplied to biomedical research, enabling the intracellular monitoring of many different species for medical and biological purposes. In this review, we focus on the developments and analytical applications of fluorescent nanoparticles in chemical and biological sensing within the intracellular environment. The review also points out the great potential of fluorescent NPs for fluorescence lifetime imaging microscopy (FLIM). Finally, we also give an overview of the current methods for delivering of fluorescent NPs into cells, where critically examine the benefits and liabilities of each strategy.

  14. Intracellular Cholesterol Trafficking and Impact in Neurodegeneration

    Directory of Open Access Journals (Sweden)

    Fabian Arenas

    2017-11-01

    Full Text Available Cholesterol is a critical component of membrane bilayers where it plays key structural and functional roles by regulating the activity of diverse signaling platforms and pathways. Particularly enriched in brain, cholesterol homeostasis in this organ is singular with respect to other tissues and exhibits a heterogeneous regulation in distinct brain cell populations. Due to the key role of cholesterol in brain physiology and function, alterations in cholesterol homeostasis and levels have been linked to brain diseases and neurodegeneration. In the case of Alzheimer disease (AD, however, this association remains unclear with evidence indicating that either increased or decreased total brain cholesterol levels contribute to this major neurodegenerative disease. Here, rather than analyzing the role of total cholesterol levels in neurodegeneration, we focus on the contribution of intracellular cholesterol pools, particularly in endolysosomes and mitochondria through its trafficking via specialized membrane domains delineated by the contacts between endoplasmic reticulum and mitochondria, in the onset of prevalent neurodegenerative diseases such as AD, Parkinson disease, and Huntington disease as well as in lysosomal disorders like Niemann-Pick type C disease. We dissect molecular events associated with intracellular cholesterol accumulation, especially in mitochondria, an event that results in impaired mitochondrial antioxidant defense and function. A better understanding of the mechanisms involved in the distribution of cholesterol in intracellular compartments may shed light on the role of cholesterol homeostasis disruption in neurodegeneration and may pave the way for specific intervention opportunities.

  15. A bacteriophage endolysin that eliminates intracellular streptococci

    Science.gov (United States)

    Shen, Yang; Barros, Marilia; Vennemann, Tarek; Gallagher, D Travis; Yin, Yizhou; Linden, Sara B; Heselpoth, Ryan D; Spencer, Dennis J; Donovan, David M; Moult, John; Fischetti, Vincent A; Heinrich, Frank; Lösche, Mathias; Nelson, Daniel C

    2016-01-01

    PlyC, a bacteriophage-encoded endolysin, lyses Streptococcus pyogenes (Spy) on contact. Here, we demonstrate that PlyC is a potent agent for controlling intracellular Spy that often underlies refractory infections. We show that the PlyC holoenzyme, mediated by its PlyCB subunit, crosses epithelial cell membranes and clears intracellular Spy in a dose-dependent manner. Quantitative studies using model membranes establish that PlyCB interacts strongly with phosphatidylserine (PS), whereas its interaction with other lipids is weak, suggesting specificity for PS as its cellular receptor. Neutron reflection further substantiates that PlyC penetrates bilayers above a PS threshold concentration. Crystallography and docking studies identify key residues that mediate PlyCB–PS interactions, which are validated by site-directed mutagenesis. This is the first report that a native endolysin can traverse epithelial membranes, thus substantiating the potential of PlyC as an antimicrobial for Spy in the extracellular and intracellular milieu and as a scaffold for engineering other functionalities. DOI: http://dx.doi.org/10.7554/eLife.13152.001 PMID:26978792

  16. Intracellular fate of Ureaplasma parvum entrapped by host cellular autophagy.

    Science.gov (United States)

    Nishiumi, Fumiko; Ogawa, Michinaga; Nakura, Yukiko; Hamada, Yusuke; Nakayama, Masahiro; Mitobe, Jiro; Hiraide, Atsushi; Sakai, Norio; Takeuchi, Makoto; Yoshimori, Tamotsu; Yanagihara, Itaru

    2017-06-01

    Genital mycoplasmas, including Ureaplasma spp., are among the smallest human pathogenic bacteria and are associated with preterm birth. Electron microscopic observation of U. parvum showed that these prokaryotes have a regular, spherical shape with a mean diameter of 146 nm. U. parvum was internalized into HeLa cells by clathrin-mediated endocytosis and survived for at least 14 days around the perinuclear region. Intracellular U. parvum reached endosomes in HeLa cells labeled with EEA1, Rab7, and LAMP-1 within 1 to 3 hr. After 3 hr of infection, U. parvum induced the cytosolic accumulation of galectin-3 and was subsequently entrapped by the autophagy marker LC3. However, when using atg7 -/- MEF cells, autophagy was inadequate for the complete elimination of U. parvum in HeLa cells. U. parvum also colocalized with the recycling endosome marker Rab11. Furthermore, the exosomes purified from infected HeLa cell culture medium included U. parvum. In these purified exosomes ureaplasma lipoprotein multiple banded antigen, host cellular annexin A2, CD9, and CD63 were detected. This research has successfully shown that Ureaplasma spp. utilize the host cellular membrane compartments possibly to evade the host immune system. © 2017 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  17. Arylthiazole antibiotics targeting intracellular methicillin-resistant Staphylococcus aureus (MRSA) that interfere with bacterial cell wall synthesis.

    Science.gov (United States)

    Eid, Islam; Elsebaei, Mohamed M; Mohammad, Haroon; Hagras, Mohamed; Peters, Christine E; Hegazy, Youssef A; Cooper, Bruce; Pogliano, Joe; Pogliano, Kit; Abulkhair, Hamada S; Seleem, Mohamed N; Mayhoub, Abdelrahman S

    2017-10-20

    The promising antibacterial potency of arylthiazole antibiotics is offset by their limited activity against intracellular bacteria (namely methicillin-resistant Staphylococcus aureus (MRSA)), similar to many clinically-approved antibiotics. The failure to target these hidden pathogens is due to the compounds' lack of proper characteristics to accumulate intracellularly. Fine tuning of the size and polar-surface-area of the linking heteroaromatic ring provided a new series of 5-thiazolylarylthiazoles with balanced properties that allow them to sufficiently cross and accumulate inside macrophages infected with MRSA. The most promising compound 4i exhibited rapid bactericidal activity, good metabolic stability and produced over 80% reduction of intracellular MRSA in infected macrophages. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  18. Feast or famine: the host-pathogen battle over amino acids.

    Science.gov (United States)

    Zhang, Yanjia J; Rubin, Eric J

    2013-07-01

    Intracellular bacterial pathogens often rely on their hosts for essential nutrients. Host cells, in turn, attempt to limit nutrient availability, using starvation as a mechanism of innate immunity. Here we discuss both host mechanisms of amino acid starvation and the diverse adaptations of pathogens to their nutrient-deprived environments. These processes provide both key insights into immune subversion and new targets for drug development. © 2013 John Wiley & Sons Ltd.

  19. Extracts against Various Pathogens

    Directory of Open Access Journals (Sweden)

    Ritika Chauhan

    2013-07-01

    The present study shows that tested lichen Parmotrema sp. extracts demonstrated a strong antimicrobial effect. That suggests the active components from methanol extracts of the investigated lichen Parmotrema sp. can be used as natural antimicrobial agent against pathogens.

  20. Evolution of microbial pathogens

    National Research Council Canada - National Science Library

    DiRita, Victor J; Seifert, H. Steven

    2006-01-01

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

  1. Indicators for waterborne pathogens

    National Research Council Canada - National Science Library

    Committee on Indicators for Waterborne Pathogens, National Research Council

    2004-01-01

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

  2. Host–Pathogen Interactions

    NARCIS (Netherlands)

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

    2011-01-01

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

  3. Obligations and responsibilities in radiation protection in the medical field

    International Nuclear Information System (INIS)

    2011-01-01

    This document briefly presents the various obligations and responsibilities of the various actors involved in or concerned by radiation protection in the medical field: the hospital administration (with respect to workers and patients), the physician (authorization and declaration, justification, optimization), the medical electro-radiology operator, the person with expertise in medical radio-physics (PSRPM), the radio-pharmacist (he is required in nuclear medicine with internal use of pharmaceutical product), the personnel with expertise in radiation protection (PCR), and other health professionals

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

    Directory of Open Access Journals (Sweden)

    Joyce C Yang

    Full Text Available 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

  5. Few Considerations on the Maintenance Obligation in the Romanian Civil Law

    Directory of Open Access Journals (Sweden)

    Mirela Costache

    2017-08-01

    Full Text Available Objectives: Recently entered into force, the Romanian Civil Code, systematized on the stable and steady values of the former civil law, reforms the matter of the maintenance obligation, regardless of the source and the legal nature of this obligation. Prior Work: This is the reason why we have chosen this topic and the analysis of the typology to which such an obligation adapts and, of course, the correlative right to which it gives birth. Approach: In our current system of law there are provided different forms of exercising this obligation, preserving, improving, but also innovating, in some aspects, the previous regulation. Specifically, we will relate in this study to a brief analysis of all types of maintenance obligations, generated by two distinct sources: the law and the will of the parties (contract, in this case we are speaking of an obligation based on the law or a contractual obligation. The angle from which we are analyzing this type of obligational relationship between the maintenance creditor and the maintenance debtor also allows us to recall both the passive or active patrimonial side, and also the analysis of the legal characters that it presupposes each of the two above-mentioned generic types of maintenance obligations. Value: Starting from the conceptualization of the maintenance obligation, the present study will be oriented towards the analysis in the current legal context of the doctrinal points of view expressed in the specialized literature, using as a method the documentary research, the interpretative method and the comparative method.

  6. Azithromycin effectiveness against intracellular infections of Francisella

    Directory of Open Access Journals (Sweden)

    Mann Barbara J

    2010-04-01

    Full Text Available Abstract Background Macrolide antibiotics are commonly administered for bacterial respiratory illnesses. Azithromycin (Az is especially noted for extremely high intracellular concentrations achieved within macrophages which is far greater than the serum concentration. Clinical strains of Type B Francisella (F. tularensis have been reported to be resistant to Az, however our laboratory Francisella strains were found to be sensitive. We hypothesized that different strains/species of Francisella (including Type A may have different susceptibilities to Az, a widely used and well-tolerated antibiotic. Results In vitro susceptibility testing of Az confirmed that F. tularensis subsp. holarctica Live Vaccine Strain (LVS (Type B was not sensitive while F. philomiragia, F. novicida, and Type A F. tularensis (NIH B38 and Schu S4 strain were susceptible. In J774A.1 mouse macrophage cells infected with F. philomiragia, F. novicida, and F. tularensis LVS, 5 μg/ml Az applied extracellularly eliminated intracellular Francisella infections. A concentration of 25 μg/ml Az was required for Francisella-infected A549 human lung epithelial cells, suggesting that macrophages are more effective at concentrating Az than epithelial cells. Mutants of RND efflux components (tolC and ftlC in F. novicida demonstrated less sensitivity to Az by MIC than the parental strain, but the tolC disc-inhibition assay demonstrated increased sensitivity, indicating a complex role for the outer-membrane transporter. Mutants of acrA and acrB mutants were less sensitive to Az than the parental strain, suggesting that AcrAB is not critical for the efflux of Az in F. novicida. In contrast, F. tularensis Schu S4 mutants ΔacrB and ΔacrA were more sensitive than the parental strain, indicating that the AcrAB may be important for Az efflux in F. tularensis Schu S4. F. novicida LPS O-antigen mutants (wbtN, wbtE, wbtQ and wbtA were found to be less sensitive in vitro to Az compared to the wild

  7. Endogenous superoxide is a key effector of the oxygen sensitivity of a model obligate anaerobe.

    Science.gov (United States)

    Lu, Zheng; Sethu, Ramakrishnan; Imlay, James A

    2018-04-03

    It has been unclear whether superoxide and/or hydrogen peroxide play important roles in the phenomenon of obligate anaerobiosis. This question was explored using Bacteroides thetaiotaomicron , a major fermentative bacterium in the human gastrointestinal tract. Aeration inactivated two enzyme families-[4Fe-4S] dehydratases and nonredox mononuclear iron enzymes-whose homologs, in contrast, remain active in aerobic Escherichia coli Inactivation-rate measurements of one such enzyme, B. thetaiotaomicron fumarase, showed that it is no more intrinsically sensitive to oxidants than is an E. coli fumarase. Indeed, when the E. coli enzymes were expressed in B. thetaiotaomicron , they no longer could tolerate aeration; conversely, the B. thetaiotaomicron enzymes maintained full activity when expressed in aerobic E. coli Thus, the aerobic inactivation of the B. thetaiotaomicron enzymes is a feature of their intracellular environment rather than of the enzymes themselves. B. thetaiotaomicron possesses superoxide dismutase and peroxidases, and it can repair damaged enzymes. However, measurements confirmed that the rate of reactive oxygen species production inside aerated B. thetaiotaomicron is far higher than in E. coli Analysis of the damaged enzymes recovered from aerated B. thetaiotaomicron suggested that they had been inactivated by superoxide rather than by hydrogen peroxide. Accordingly, overproduction of superoxide dismutase substantially protected the enzymes from aeration. We conclude that when this anaerobe encounters oxygen, its internal superoxide levels rise high enough to inactivate key catabolic and biosynthetic enzymes. Superoxide thus comprises a major element of the oxygen sensitivity of this anaerobe. The extent to which molecular oxygen exerts additional direct effects remains to be determined.

  8. Obligations and responsibilities in radiation protection in the medical field; Obligations et responsabilites en radioprotection dans le domaine medical

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    This document briefly presents the various obligations and responsibilities of the various actors involved in or concerned by radiation protection in the medical field: the hospital administration (with respect to workers and patients), the physician (authorization and declaration, justification, optimization), the medical electro-radiology operator, the person with expertise in medical radio-physics (PSRPM), the radio-pharmacist (he is required in nuclear medicine with internal use of pharmaceutical product), the personnel with expertise in radiation protection (PCR), and other health professionals

  9. Protecting the Minor by Guardianship. Guardian’s Rights and Obligations and Parental Rights and Obligations. Comparative Aspects

    OpenAIRE

    Gavrilescu, Alin-Gheorghe

    2010-01-01

    The minor’s guardianship is a juridical institution by means of which the person called guardian provides the protection of the child’s person and patrimony, because the child does not have temporarily or irrevocably his parents’ protection or, in order to accomplish his interests, the child cannot be let in their care. As the content of protecting the minor by parents, the one of protecting him or her by guardianship is formed by a personal side, composed of the rights and the obligations ha...

  10. Mechanisms of Funding for Universal Service Obligations: the Electricity Case

    International Nuclear Information System (INIS)

    Mirabel, Francois; Poudou, Jean-Christophe

    2001-06-01

    The transition towards a more competitive regime in network industries (and specially in electricity sector) raises the relevant question of funding for the Universal Service Obligations (USOs). Our paper focuses on two ways of funding for universal service and equal treatment obligations (?Ubiquity and Non Discrimination constraints?): the funding through access charge (CS regime) or taxation (T regime). Using a network model including competition between an historical monopoly (in charge for the USOs) and an entrant, we obtain some results concerning gains and losses of social welfare due to those mechanisms. We show that most of the time it is socially better to let the historical monopoly be active whatever the type of funding for USOs applying, and whatever profitability of the firms is. However, when the entrant is active, we can highlight that the introduction of the T regime (compared to the CS one) implies either welfare deterioration or an entry prevention strategy by the historical firm. Therefore, the T regime could not be an argument for the regulator to promote vertical separation of the historical firm (according to the European community line). (authors)

  11. Mechanisms of funding for Universal Service Obligations. The electricity case

    International Nuclear Information System (INIS)

    Mirabel, Francois; Poudou, Jean-Christophe

    2004-01-01

    The transition towards a more competitive regime in network industries (and specially in electricity sector) raises the relevant question of funding for the Universal Service Obligations (USOs). Our paper focuses on two ways of funding for universal service and equal treatment obligations ('Ubiquity and Nondiscrimination constraints, UND'): the funding through access charge (CS regime) or taxation (T regime). Using a network model including competition between a historical monopoly (in charge for the USOs) and an entrant, we obtain some results concerning gains and losses of social welfare due to those mechanisms. We show that most of the time it is socially better to let the historical monopoly be active whatever the type of funding for USOs applying, and whatever profitability of the firms is. However, when the entrant is active, we can highlight that the introduction of the T regime (compared to the CS one) implies either welfare deterioration or an entry prevention strategy by the historical firm. Therefore, the T regime could not be an argument for the regulator to promote vertical separation of the historical firm (according to the European community line)

  12. Mechanisms of funding for Universal Service Obligations: the electricity case

    International Nuclear Information System (INIS)

    Mirabel, F.; Poudou, J.C.

    2004-01-01

    The transition towards a more competitive regime in network industries (and specially in electricity sector) raises the relevant question of funding for the Universal Service Obligations (USOs). Our paper focuses on two ways of funding for universal service and equal treatment obligations ''Ubiquity and Nondiscrimination constraints, UND'': the funding through access charge (CS regime) or taxation (T regime). Using a network model including competition between a historical monopoly (in charge for the USOs) and an entrant, we obtain some results concerning gains and losses of social welfare due to those mechanisms. We show that most of the time it is socially better to let the historical monopoly be active whatever the type of funding for USOs applying, and whatever profitability of the firms is. However, when the entrant is active, we can highlight that the introduction of the T regime (compared to the CS one) implies either welfare deterioration or an entry prevention strategy by the historical firm. Therefore, the T regime could not be an argument for the regulator to promote vertical separation of the historical firm (according to the European community line). (author)

  13. Uranium mine tailings and obligations to future generations

    International Nuclear Information System (INIS)

    Brook, A.

    1980-01-01

    Low-level wastes from uranium mine/mill operations, because of their huge volume, are a serious problem, yet relatively little attention has been paid to them. Management of tailings piles and waste liquids in the short term is fairly effective. However these management techniques involve continuous, active treatment of the wastes, which may not continue after operations shut down, and rely on containment structures with a short effective life. Tailings can probably be rendered safe for future generations if sufficient resources are devoted to the task. The central moral question is whether we are obligated to assume the costs of tailings management, or whether it is permissible to pass them on to future generations. The basic moral principle that each person has the same value as any other implies that the generation that reaps the benefits of nuclear power must assume the costs of managing mine tailings and not discriminate in favour of one group of persons, our own generation. The argument that people who may exist in the future have intrinsically less value than people currently alive is not accepted by the author. The methodology for determining obligations to future generations which has been applied to mine/mill wastes could be applied to other nuclear issues, too. (LL)

  14. Intracellular bacteria: the origin of dinoflagellate toxicity.

    Science.gov (United States)

    Silva, E S

    1990-01-01

    Dinoflagellate blooms of the same species have been registered either as toxic or nontoxic and, in the latter case, toxicity may be of different types. A hypothesis has been formulated according to which the bacteria having in some way taken part in the toxin formation are either inside the dinoflagellate cell or in the nutritive liquid. The presence of intracellular bacteria in those microorganisms has been studied mainly in material from cultures, a few from the sea, and several strains were isolated from different species. Experiments with crossed inoculations have shown that the bacterial strain from Gonyaulax tamarensis caused the cells of some other species to become toxic. From nontoxic clonal cultures of Prorocentrum balticum, Glenodinium foliaceum, and Gyrodinium instriatum, after inoculation of that bacterial strain, cultures were obtained whose cell extracts showed the same kind of toxicity as G. tamarensis. No toxic action could be found in the extracts of the bacterial cells form the assayed strains. The interference of intracellular bacteria in the metabolism of dinoflagellates must be the main cause of their toxicity.

  15. Fluorescent nanoparticles for intracellular sensing: a review.

    Science.gov (United States)

    Ruedas-Rama, Maria J; Walters, Jamie D; Orte, Angel; Hall, Elizabeth A H

    2012-11-02

    Fluorescent nanoparticles (NPs), including semiconductor NPs (Quantum Dots), metal NPs, silica NPs, polymer NPs, etc., have been a major focus of research and development during the past decade. The fluorescent nanoparticles show unique chemical and optical properties, such as brighter fluorescence, higher photostability and higher biocompatibility, compared to classical fluorescent organic dyes. Moreover, the nanoparticles can also act as multivalent scaffolds for the realization of supramolecular assemblies, since their high surface to volume ratio allow distinct spatial domains to be functionalized, which can provide a versatile synthetic platform for the implementation of different sensing schemes. Their excellent properties make them one of the most useful tools that chemistry has supplied to biomedical research, enabling the intracellular monitoring of many different species for medical and biological purposes. In this review, we focus on the developments and analytical applications of fluorescent nanoparticles in chemical and biological sensing within the intracellular environment. The review also points out the great potential of fluorescent NPs for fluorescence lifetime imaging microscopy (FLIM). Finally, we also give an overview of the current methods for delivering of fluorescent NPs into cells, where critically examine the benefits and liabilities of each strategy. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. [Intracellular signaling mechanisms in thyroid cancer].

    Science.gov (United States)

    Mondragón-Terán, Paul; López-Hernández, Luz Berenice; Gutiérrez-Salinas, José; Suárez-Cuenca, Juan Antonio; Luna-Ceballos, Rosa Isela; Erazo Valle-Solís, Aura

    2016-01-01

    Thyroid cancer is the most common malignancy of the endocrine system, the papillary variant accounts for 80-90% of all diagnosed cases. In the development of papillary thyroid cancer, BRAF and RAS genes are mainly affected, resulting in a modification of the system of intracellular signaling proteins known as «protein kinase mitogen-activated» (MAPK) which consist of «modules» of internal signaling proteins (Receptor/Ras/Raf/MEK/ERK) from the cell membrane to the nucleus. In thyroid cancer, these signanling proteins regulate diverse cellular processes such as differentiation, growth, development and apoptosis. MAPK play an important role in the pathogenesis of thyroid cancer as they are used as molecular biomarkers for diagnostic, prognostic and as possible therapeutic molecular targets. Mutations in BRAF gene have been correlated with poor response to treatment with traditional chemotherapy and as an indicator of poor prognosis. To review the molecular mechanisms involved in intracellular signaling of BRAF and RAS genes in thyroid cancer. Molecular therapy research is in progress for this type of cancer as new molecules have been developed in order to inhibit any of the components of the signaling pathway (RET/PTC)/Ras/Raf/MEK/ERK; with special emphasis on the (RET/PTC)/Ras/Raf section, which is a major effector of ERK pathway. Copyright © 2016 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

  17. Bacterial pathogen manipulation of host membrane trafficking.

    Science.gov (United States)

    Asrat, Seblewongel; de Jesús, Dennise A; Hempstead, Andrew D; Ramabhadran, Vinay; Isberg, Ralph R

    2014-01-01

    Pathogens use a vast number of strategies to alter host membrane dynamics. Targeting the host membrane machinery is important for the survival and pathogenesis of several extracellular, vacuolar, and cytosolic bacteria. Membrane manipulation promotes bacterial replication while suppressing host responses, allowing the bacterium to thrive in a hostile environment. This review provides a comprehensive summary of various strategies used by both extracellular and intracellular bacteria to hijack host membrane trafficking machinery. We start with mechanisms used by bacteria to alter the plasma membrane, delve into the hijacking of various vesicle trafficking pathways, and conclude by summarizing bacterial adaptation to host immune responses. Understanding bacterial manipulation of host membrane trafficking provides insights into bacterial pathogenesis and uncovers the molecular mechanisms behind various processes within a eukaryotic cell.

  18. In Vitro Antimicrobial Potential of the Lichen Parmotrema sp. Extracts against Various Pathogens

    OpenAIRE

    Chauhan, Ritika; Abraham, Jayanthi

    2013-01-01

      Objective(s):   The ongoing increasing antibiotic resistance is one of the biggest challenges faced by global public health. The perennial need for new antimicrobials against a background of increasing antibiotic resistance in pathogenic and opportunistic microorganisms obliges the scientific community to constantly develop new drugs and antimicrobial agents. Lichens are known prolific sources of natural antimicrobial drugs and biologically active natural products. This study ...

  19. Autophagy response: manipulating the mTOR-controlled machinery by amino acids and pathogens.

    Science.gov (United States)

    Fader, Claudio Marcelo; Aguilera, Milton Osmar; Colombo, María Isabel

    2015-10-01

    Macroautophagy is a self-degradative process that normally maintains cellular homeostasis via a lysosomal pathway. It is induced by different stress signals, including nutrients and growth factors' restriction as well as pathogen invasions. These stimuli are modulated by the serine/threonine protein kinase mammalian target of rapamycin (mTOR) which control not only autophagy but also protein translation and gene expression. This review focuses on the important role of mTOR as a master regulator of cell growth and the autophagy pathway. Here, we have discussed the role of intracellular amino acid availability and intracellular pH in the redistribution of autophagic structures, which may contribute to mammalian target of rapamycin complex 1 (mTORC1) activity regulation. We have also discussed that mTORC1 complex and components of the autophagy machinery are localized at the lysosomal surface, representing a fascinating mechanism to control the metabolism, cellular clearance and also to restrain invading intracellular pathogens.

  20. Obligations of low income countries in ensuring equity in global health financing.

    Science.gov (United States)

    Barugahare, John; Lie, Reidar K

    2015-09-08

    Despite common recognition of joint responsibility for global health by all countries particularly to ensure justice in global health, current discussions of countries' obligations for global health largely ignore obligations of developing countries. This is especially the case with regards to obligations relating to health financing. Bearing in mind that it is not possible to achieve justice in global health without achieving equity in health financing at both domestic and global levels, our aim is to show how fulfilling the obligation we propose will make it easy to achieve equity in health financing at both domestic and international levels. Achieving equity in global health financing is a crucial step towards achieving justice in global health. Our general view is that current discussions on global health equity largely ignore obligations of Low Income Country (LIC) governments and we recommend that these obligations should be mainstreamed in current discussions. While we recognise that various obligations need to be fulfilled in order to ultimately achieve justice in global health, for lack of space we prioritise obligations for health financing. Basing on the evidence that in most LICs health is not given priority in annual budget allocations, we propose that LIC governments should bear an obligation to allocate a certain minimum percent of their annual domestic budget resources to health, while they await external resources to supplement domestic ones. We recommend and demonstrate a mechanism for coordinating this obligation so that if the resulting obligations are fulfilled by both LIC and HIC governments it will be easy to achieve equity in global health financing. Although achieving justice in global health will depend on fulfillment of different categories of obligations, ensuring inter- and intra-country equity in health financing is pivotal. This can be achieved by requiring all LIC governments to allocate a certain optimal per cent of their domestic

  1. Isolation of obligate and facultative anaerobic bacteria from feline subcutaneous abscesses.

    Science.gov (United States)

    Hoshuyama, S; Kanoe, M; Amimoto, A

    1996-03-01

    A total of 113 specimens collected from purulent skin lesions of household cats was examined bacteriologically. Ninety seven isolates obtained from 74 specimens (65.5%). Of these, 11 specimens (9.7%) contained obligate anaerobes only, 18 specimens (15.9%) yielded both obligate and facultative anaerobes. In the obligate anaerobes detected, genus Fusobacterium was the most frequently observed and F. nucleatum was most common species. Pasteurella multocida was the facultative anaerobe which was most frequently detected.

  2. Viral pathogen discovery

    Science.gov (United States)

    Chiu, Charles Y

    2015-01-01

    Viral pathogen discovery is of critical importance to clinical microbiology, infectious diseases, and public health. Genomic approaches for pathogen discovery, including consensus polymerase chain reaction (PCR), microarrays, and unbiased next-generation sequencing (NGS), have the capacity to comprehensively identify novel microbes present in clinical samples. Although numerous challenges remain to be addressed, including the bioinformatics analysis and interpretation of large datasets, these technologies have been successful in rapidly identifying emerging outbreak threats, screening vaccines and other biological products for microbial contamination, and discovering novel viruses associated with both acute and chronic illnesses. Downstream studies such as genome assembly, epidemiologic screening, and a culture system or animal model of infection are necessary to establish an association of a candidate pathogen with disease. PMID:23725672

  3. Highly pathogenic avian influenza.

    Science.gov (United States)

    Swayne, D E; Suarez, D L

    2000-08-01

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

  4. Single Cystosorus Isolate Production and Restriction Fragment Length Polymorphism Characterization of the Obligate Biotroph Spongospora subterranea f. sp. subterranea.

    Science.gov (United States)

    Qu, Xinshun; Christ, Barbara J

    2006-10-01

    ABSTRACT Spongospora subterranea f. sp. subterranea causes powdery scab in potatoes and is distributed worldwide. Genetic studies of this pathogen have been hampered due, in part, to its obligate parasitism and the lack of molecular markers for this pathogen. In this investigation, a single cystosorus inoculation technique was developed to produce large amounts of S. subterranea f. sp. subterranea plasmodia or zoosporangia in eastern black nightshade (Solanum ptycanthum) roots from which DNA was extracted. Cryopreservation of zoosporangia was used for long-term storage of the isolates. S. subterranea f. sp. subterranea-specific restriction fragment length polymorphism (RFLP) markers were developed from randomly amplified polymorphic DNA (RAPD) fragments. Cystosori of S. subterranea f. sp. subterranea were used for RAPD assays and putative pathogen-specific RAPD fragments were cloned and sequenced. The fragments were screened for specificity by Southern hybridization and subsequent DNA sequence BLAST search. Four polymorphic S. subterranea f. sp. subterranea-specific probes containing repetitive elements, and one containing single copy DNA were identified. These RFLP probes were then used to analyze 24 single cystosorus isolates derived from eight geographic locations in the United States and Canada. Genetic variation was recorded among, but not within, geographic locations. Cluster analysis separated the isolates into two major groups: group I included isolates originating from western North America, with the exception of those from Colorado, and group II included isolates originating from eastern North America and from Colorado. The techniques developed in this study, i.e., production of single cystosorus isolates of S. subterranea f. sp. subterranea and development of RFLP markers for this pathogen, provide methods to further study the genetic structure of S. subterranea f. sp. subterranea.

  5. Family obligation values as a protective and vulnerability factor among low-income adolescent girls.

    Science.gov (United States)

    Milan, Stephanie; Wortel, Sanne

    2015-06-01

    Adolescents' beliefs about family obligation often reflect cultural variations in their family context, and thus are important for understanding development among diverse youth. In this study, we test hypotheses about the role of family obligation values in risk behavior and mental health in a sample of 194 low-income adolescent girls (mean age = 15.2; 58% Latina, 28% African-American/Black). We hypothesized that family obligation values can be both a protective and vulnerability factor, depending on the type of outcome and the presence of other risk factors. Across the sample, higher family obligation values tended to occur with indicators of positive family functioning (e.g., more frequent communication, less maternal hostility) based on mother and adolescent reports. As hypothesized, family obligation values moderated the relationship between established risk factors and adjustment in distinct ways, such that high family obligation values decreased risk in some domains (i.e., a protective factor) but increased risk in other domains (i.e., a vulnerability factor). Specifically, high family obligation values diminished the relationship between peer norms for risky behavior (sex and substance use) and individual engagement in those behaviors. At the same time, high family obligation values magnified the relationship between exposure to negative life events and poor mental health (PTSD and depressive symptoms). The results suggest that family obligation is an important but complex aspect of development among diverse adolescent girls.

  6. Family Obligation Values as a Protective and Vulnerability Factor among Low-Income Adolescent Girls

    Science.gov (United States)

    Milan, Stephanie; Wortel, Sanne

    2014-01-01

    Adolescents’ beliefs about family obligation often reflect cultural variations in their family context, and thus are important for understanding development among diverse youth. In this study, we test hypotheses about the role of family obligation values in risk behavior and mental health in a sample of 194 low-income adolescent girls (Mean age = 15.2; 58% Latina, 28% African-American/Black). We hypothesized that family obligation values can be both a protective and vulnerability factor, depending on the type of outcome and the presence of other risk factors. Across the sample, higher family obligation values tended to occur with indicators of positive family functioning (e.g., more frequent communication, less maternal hostility) based on mother and adolescent reports. As hypothesized, family obligation values moderated the relationship between established risk factors and adjustment in distinct ways, such that high family obligation values decreased risk in some domains (i.e., a protective factor) but increased risk in other domains (i.e., a vulnerability factor). Specifically, high family obligation values diminished the relationship between peer norms for risky behavior (sex and substance use) and individual engagement in those behaviors. At the same time, high family obligation values magnified the relationship between exposure to negative life events and poor mental health (PTSD and depressive symptoms). The results suggest that family obligation is an important but complex aspect of development among diverse adolescent girls. PMID:25351163

  7. Nanobodies: Chemical Functionalization Strategies and Intracellular Applications

    Science.gov (United States)

    Schumacher, Dominik; Helma, Jonas; Schneider, Anselm F. L.; Leonhardt, Heinrich

    2018-01-01

    Abstract Nanobodies can be seen as next‐generation tools for the recognition and modulation of antigens that are inaccessible to conventional antibodies. Due to their compact structure and high stability, nanobodies see frequent usage in basic research, and their chemical functionalization opens the way towards promising diagnostic and therapeutic applications. In this Review, central aspects of nanobody functionalization are presented, together with selected applications. While early conjugation strategies relied on the random modification of natural amino acids, more recent studies have focused on the site‐specific attachment of functional moieties. Such techniques include chemoenzymatic approaches, expressed protein ligation, and amber suppression in combination with bioorthogonal modification strategies. Recent applications range from sophisticated imaging and mass spectrometry to the delivery of nanobodies into living cells for the visualization and manipulation of intracellular antigens. PMID:28913971

  8. Drosophila VAMP7 regulates Wingless intracellular trafficking.

    Science.gov (United States)

    Gao, Han; He, Fang; Lin, Xinhua; Wu, Yihui

    2017-01-01

    Drosophila Wingless (Wg) is a morphogen that determines cell fate during development. Previous studies have shown that endocytic pathways regulate Wg trafficking and signaling. Here, we showed that loss of vamp7, a gene required for vesicle fusion, dramatically increased Wg levels and decreased Wg signaling. Interestingly, we found that levels of Dally-like (Dlp), a glypican that can interact with Wg to suppress Wg signaling at the dorsoventral boundary of the Drosophila wing, were also increased in vamp7 mutant cells. Moreover, Wg puncta in Rab4-dependent recycling endosomes were Dlp positive. We hypothesize that VAMP7 is required for Wg intracellular trafficking and the accumulation of Wg in Rab4-dependent recycling endosomes might affect Wg signaling.

  9. Intracellular pH in sperm physiology.

    Science.gov (United States)

    Nishigaki, Takuya; José, Omar; González-Cota, Ana Laura; Romero, Francisco; Treviño, Claudia L; Darszon, Alberto

    2014-08-01

    Intracellular pH (pHi) regulation is essential for cell function. Notably, several unique sperm ion transporters and enzymes whose elimination causes infertility are either pHi dependent or somehow related to pHi regulation. Amongst them are: CatSper, a Ca(2+) channel; Slo3, a K(+) channel; the sperm-specific Na(+)/H(+) exchanger and the soluble adenylyl cyclase. It is thus clear that pHi regulation is of the utmost importance for sperm physiology. This review briefly summarizes the key components involved in pHi regulation, their characteristics and participation in fundamental sperm functions such as motility, maturation and the acrosome reaction. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Nanobodies: Chemical Functionalization Strategies and Intracellular Applications.

    Science.gov (United States)

    Schumacher, Dominik; Helma, Jonas; Schneider, Anselm F L; Leonhardt, Heinrich; Hackenberger, Christian P R

    2018-02-23

    Nanobodies can be seen as next-generation tools for the recognition and modulation of antigens that are inaccessible to conventional antibodies. Due to their compact structure and high stability, nanobodies see frequent usage in basic research, and their chemical functionalization opens the way towards promising diagnostic and therapeutic applications. In this Review, central aspects of nanobody functionalization are presented, together with selected applications. While early conjugation strategies relied on the random modification of natural amino acids, more recent studies have focused on the site-specific attachment of functional moieties. Such techniques include chemoenzymatic approaches, expressed protein ligation, and amber suppression in combination with bioorthogonal modification strategies. Recent applications range from sophisticated imaging and mass spectrometry to the delivery of nanobodies into living cells for the visualization and manipulation of intracellular antigens. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  11. Intracellular Signalling by C-Peptide

    Directory of Open Access Journals (Sweden)

    Claire E. Hills

    2008-01-01

    Full Text Available C-peptide, a cleavage product of the proinsulin molecule, has long been regarded as biologically inert, serving merely as a surrogate marker for insulin release. Recent findings demonstrate both a physiological and protective role of C-peptide when administered to individuals with type I diabetes. Data indicate that C-peptide appears to bind in nanomolar concentrations to a cell surface receptor which is most likely to be G-protein coupled. Binding of C-peptide initiates multiple cellular effects, evoking a rise in intracellular calcium, increased PI-3-kinase activity, stimulation of the Na+/K+ ATPase, increased eNOS transcription, and activation of the MAPK signalling pathway. These cell signalling effects have been studied in multiple cell types from multiple tissues. Overall these observations raise the possibility that C-peptide may serve as a potential therapeutic agent for the treatment or prevention of long-term complications associated with diabetes.

  12. Intracellular sphingosine releases calcium from lysosomes.

    Science.gov (United States)

    Höglinger, Doris; Haberkant, Per; Aguilera-Romero, Auxiliadora; Riezman, Howard; Porter, Forbes D; Platt, Frances M; Galione, Antony; Schultz, Carsten

    2015-11-27

    To elucidate new functions of sphingosine (Sph), we demonstrate that the spontaneous elevation of intracellular Sph levels via caged Sph leads to a significant and transient calcium release from acidic stores that is independent of sphingosine 1-phosphate, extracellular and ER calcium levels. This photo-induced Sph-driven calcium release requires the two-pore channel 1 (TPC1) residing on endosomes and lysosomes. Further, uncaging of Sph leads to the translocation of the autophagy-relevant transcription factor EB (TFEB) to the nucleus specifically after lysosomal calcium release. We confirm that Sph accumulates in late endosomes and lysosomes of cells derived from Niemann-Pick disease type C (NPC) patients and demonstrate a greatly reduced calcium release upon Sph uncaging. We conclude that sphingosine is a positive regulator of calcium release from acidic stores and that understanding the interplay between Sph homeostasis, calcium signaling and autophagy will be crucial in developing new therapies for lipid storage disorders such as NPC.

  13. [Limbic encephalitis with antibodies against intracellular antigens].

    Science.gov (United States)

    Morita, Akihiko; Kamei, Satoshi

    2010-04-01

    Limbic encephalitis is a paraneoplastic syndrome that is often associated with small cell lung cancer (SCLC), breast cancer, testicular tumors, teratoma, Hodgkin's lymphoma and thymoma. The common clinical manifestations of limbic encephalitis are subacute onset, cognitive dysfunction, seizures and psychiatric symptoms. Paraneoplastic neurological disorders are considered to occur because of cytotoxic T cell responses and antibodies against target neuronal proteins that are usually expressed by an underlying tumor. The main intracellular antigens related to limbic encephalitis are Hu, Ma2, and less frequently CV2/CRMP5 and amphiphysin. The anti-Hu antibody, which is involved in cerebellar degeneration and extensive or multifocal encephalomyelitis such as limbic encephalitis is closely associated with a history of smoking and SCLC. The anti-Ma2 antibody is associated with encephalitis of the limbic system, hypothalamus and brain-stem. For this reason, some patients with limbic encephalitis have sleep disorders (including REM sleep abnormalities), severe hypokinesis and gaze palsy in addition to limbic dysfunction. In men aged less than 50 years, anti-Ma2 antibody encephalitis is almost always associated with testicular germ-cell tumors that are occasionally difficult to detect. In older men and women, the most common tumors are non-SCLC and breast cancer. Limbic encephalitis associated with cell-surface antigens (e.g., voltage-gated potassium channels, NMDA receptors) is mediated by antibodies and often improves after a reduction in the antibody titer and after tumor resection. Patients with antibodies against intracellular antigens, except for those with anti-Ma2 antibodies and testicular tumors, are less responsive. Early diagnosis and treatment with immunotherapy, tumor resection or both are important for improving or stabilizing the condition of limbic encephalitis.

  14. Transfer of Rights and Obligations Under DCFR and CESL

    DEFF Research Database (Denmark)

    Beale, Hugh; Ringe, Georg

    The rules on assignment and transfer of rights and obligations are currently outside the scope of the proposed CESL. In contrast, the original DCFR from 2009 includes a chapter on these issues. Questions outside the scope of CESL are left to be solved by the ‘domestic’ provisions of the national....... This concerns above all other areas of law, for example the rules that apply upon the insolvency of one of the parties (in particular that of the assignor) and the rules on public policy. Key differences between the jurisdictions include, inter alia, the proprietary aspects of the assignor’s insolvency where...... the assignor is paid by the debtor, the priority rule for competing assignments, and the effects of a non-assignment clause. Here, the choice of the optional instrument rather than either English or German law will lead to diverging results and may therefore prejudice any of the parties involved....

  15. Scientists' Ethical Obligations and Social Responsibility for Nanotechnology Research.

    Science.gov (United States)

    Corley, Elizabeth A; Kim, Youngjae; Scheufele, Dietram A

    2016-02-01

    Scientists' sense of social responsibility is particularly relevant for emerging technologies. Since a regulatory vacuum can sometimes occur in the early stages of these technologies, individual scientists' social responsibility might be one of the most significant checks on the risks and negative consequences of this scientific research. In this article, we analyze data from a 2011 mail survey of leading U.S. nanoscientists to explore their perceptions the regarding social and ethical responsibilities for their nanotechnology research. Our analyses show that leading U.S. nanoscientists express a moderate level of social responsibility about their research. Yet, they have a strong sense of ethical obligation to protect laboratory workers (in both universities and industry) from unhealthy exposure to nanomaterials. We also find that there are significant differences in scientists' sense of social and ethical responsibility depending on their demographic characteristics, job affiliation, attention to media content, risk perceptions and benefit perceptions. We conclude with some implications for future research.

  16. An integrated moral obligation model for landowner conservation norms

    Science.gov (United States)

    Pradhananga, Amit K.; Davenport, Mae A.; Fulton, David C.; Maruyama, Geoffrey M.; Current, Dean

    2017-01-01

    This study applies an integrated moral obligation model to examine the role of environmental and cultural values, and beliefs in the activation of landowner conservation norms. Data for this study were collected through a self-administered survey of riparian landowners in two Minnesota watersheds: Sand Creek and Vermillion River watersheds. Study findings suggest that collectivistic and biospheric–altruistic values form the bases for the activation of personal norms. Further, beliefs about local responsibility and ability to act influence personal norms to protect water resources. Findings suggest that landowners’ personal norms of water conservation are more likely to be activated by conservation strategies that appeal to biospheric–altruistic and collectivistic values, emphasize adverse consequences of water pollution, highlight water resource protection as a local responsibility, and provide the resources needed to protect water resources.

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

    Science.gov (United States)

    Kadzielska, Joanna; Kierzkowska, Marta; Sawicka-Grzelak, Anna; Rokosz, Alicja; Łuczak, Mirosław

    2007-01-01

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

  18. Exometabolomics Assisted Design and Validation of Synthetic Obligate Mutualism.

    Science.gov (United States)

    Kosina, Suzanne M; Danielewicz, Megan A; Mohammed, Mujahid; Ray, Jayashree; Suh, Yumi; Yilmaz, Suzan; Singh, Anup K; Arkin, Adam P; Deutschbauer, Adam M; Northen, Trent R

    2016-07-15

    Synthetic microbial ecology has the potential to enhance the productivity and resiliency of biotechnology processes compared to approaches using single isolates. Engineering microbial consortia is challenging; however, one approach that has attracted significant attention is the creation of synthetic obligate mutualism using auxotrophic mutants that depend on each other for exchange or cross-feeding of metabolites. Here, we describe the integration of mutant library fitness profiling with mass spectrometry based exometabolomics as a method for constructing synthetic mutualism based on cross-feeding. Two industrially important species lacking known ecological interactions, Zymomonas mobilis and Escherichia coli, were selected as the test species. Amino acid exometabolites identified in the spent medium of Z. mobilis were used to select three corresponding E. coli auxotrophs (proA, pheA and IlvA), as potential E. coli counterparts for the coculture. A pooled mutant fitness assay with a Z. mobilis transposon mutant library was used to identify mutants with improved growth in the presence of E. coli. An auxotroph mutant in a gene (ZMO0748) with sequence similarity to cysteine synthase A (cysK), was selected as the Z. mobilis counterpart for the coculture. Exometabolomic analysis of spent E. coli medium identified glutathione related metabolites as potentially available for rescue of the Z. mobilis cysteine synthase mutant. Three sets of cocultures between the Z. mobilis auxotroph and each of the three E. coli auxotrophs were monitored by optical density for growth and analyzed by flow cytometry to confirm high cell counts for each species. Taken together, our methods provide a technological framework for creating synthetic mutualisms combining existing screening based methods and exometabolomics for both the selection of obligate mutualism partners and elucidation of metabolites involved in auxotroph rescue.

  19. Human pathogen avoidance adaptations

    NARCIS (Netherlands)

    Tybur, J.M.; Lieberman, D.

    2016-01-01

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

  20. Single-cell intracellular nano-pH probes†

    OpenAIRE

    Özel, Rıfat Emrah; Lohith, Akshar; Mak, Wai Han; Pourmand, Nader

    2015-01-01

    Within a large clonal population, such as cancerous tumor entities, cells are not identical, and the differences between intracellular pH levels of individual cells may be important indicators of heterogeneity that could be relevant in clinical practice, especially in personalized medicine. Therefore, the detection of the intracellular pH at the single-cell level is of great importance to identify and study outlier cells. However, quantitative and real-time measurements of the intracellular p...

  1. Autophagy in plant pathogenic fungi.

    Science.gov (United States)

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

    2016-09-01

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

  2. AMP-activated Protein Kinase As a Target For Pathogens: Friends Or Foes?

    Science.gov (United States)

    Moreira, Diana; Silvestre, Ricardo; Cordeiro-da-Silva, Anabela; Estaquier, Jérôme; Foretz, Marc; Viollet, Benoit

    2016-01-01

    Intracellular pathogens are known to manipulate host cell regulatory pathways to establish an optimal environment for their growth and survival. Pathogens employ active mechanisms to hijack host cell metabolism and acquire existing nutrient and energy store. The role of the cellular energy sensor AMP-activated protein kinase (AMPK) in the regulation of cellular energy homeostasis is well documented. Here, we highlight recent advances showing the importance of AMPK signaling in pathogen-host interactions. Pathogens interact with AMPK by a variety of mechanisms aimed at reprogramming host cell metabolism to their own benefit. Stimulation of AMPK activity provides an efficient process to rapidly adapt pathogen metabolism to the major nutritional changes often encountered during the different phases of infection. However, inhibition of AMPK is also used by pathogens to manipulate innate host response, indicating that AMPK appears relevant to restriction of pathogen infection. We also document the effects of pharmacological AMPK modulators on pathogen proliferation and survival. This review illustrates intricate pathogen-AMPK interactions that may be exploited to the development of novel anti-pathogen therapies.

  3. Intracellular zinc flux causes reactive oxygen species mediated mitochondrial dysfunction leading to cell death in Leishmania donovani.

    Directory of Open Access Journals (Sweden)

    Anjali Kumari

    Full Text Available Leishmaniasis caused by Leishmania parasite is a global threat to public health and one of the most neglected tropical diseases. Therefore, the discovery of novel drug targets and effective drug is a major challenge and an important goal. Leishmania is an obligate intracellular parasite that alternates between sand fly and human host. To survive and establish infections, Leishmania parasites scavenge and internalize nutrients from the host. Nevertheless, host cells presents mechanism like nutrient restriction to inhibit microbial growth and control infection. Zinc is crucial for cellular growth and disruption in its homeostasis hinders growth and survival in many cells. However, little is known about the role of zinc in Leishmania growth and survival. In this study, the effect of zinc on the growth and survival of L.donovani was analyzed by both Zinc-depletion and Zinc-supplementation using Zinc-specific chelator N, N, N', N'-tetrakis (2-pyridylmethyl ethylenediamine (TPEN and Zinc Sulfate (ZnSO4. Treatment of parasites with TPEN rather than ZnSO4 had significantly affected the growth in a dose- and time-dependent manner. The pre-treatment of promastigotes with TPEN resulted into reduced host-parasite interaction as indicated by decreased association index. Zn depletion resulted into flux in intracellular labile Zn pool and increased in ROS generation correlated with decreased intracellular total thiol and retention of plasma membrane integrity without phosphatidylserine exposure in TPEN treated promastigotes. We also observed that TPEN-induced Zn depletion resulted into collapse of mitochondrial membrane potential which is associated with increase in cytosolic calcium and cytochrome-c. DNA fragmentation analysis showed increased DNA fragments in Zn-depleted cells. In summary, intracellular Zn depletion in the L. donovani promastigotes led to ROS-mediated caspase-independent mitochondrial dysfunction resulting into apoptosis-like cell death

  4. Structure and Biological Activity of Pathogen-like Synthetic Nanomedicines

    Science.gov (United States)

    Lőrincz, Orsolya; Tőke, Enikő R.; Somogyi, Eszter; Horkay, Ferenc; Chandran, Preethi; Douglas, Jack F.; Szebeni, János; Lisziewicz, Julianna

    2011-01-01

    Here we characterize the structure, stability and intracellular mode-of-action of DermaVir nanomedicine that is under clinical development for the treatment of HIV/AIDS. This nanomedicine is comprised of pathogen-like pDNA/PEIm nanoparticles (NPs) having the structure and function resembling spherical viruses that naturally evolved to deliver nucleic acids to the cells. Atomic force microscopy demonstrated spherical 100–200nm NPs with a smooth polymer surface protecting the pDNA in the core. Optical-absorption determined both the NP structural stability and biological activity relevant to their ability to escape from the endosome and release the pDNA at the nucleus. Salt, pH and temperature influence the nanomedicine shelf-life and intracellular stability. This approach facilitates the development of diverse polyplex nanomedicines where the delivered pDNA-expressed antigens induce immune responses to kill infected cells. PMID:21839051

  5. New insights into valve-related intramural and intracellular bacterial diversity in infective endocarditis.

    Science.gov (United States)

    Oberbach, Andreas; Schlichting, Nadine; Feder, Stefan; Lehmann, Stefanie; Kullnick, Yvonne; Buschmann, Tilo; Blumert, Conny; Horn, Friedemann; Neuhaus, Jochen; Neujahr, Ralph; Bagaev, Erik; Hagl, Christian; Pichlmaier, Maximilian; Rodloff, Arne Christian; Gräber, Sandra; Kirsch, Katharina; Sandri, Marcus; Kumbhari, Vivek; Behzadi, Armirhossein; Behzadi, Amirali; Correia, Joao Carlos; Mohr, Friedrich Wilhelm; Friedrich, Maik

    2017-01-01

    In infective endocarditis (IE), a severe inflammatory disease of the endocardium with an unchanged incidence and mortality rate over the past decades, only 1% of the cases have been described as polymicrobial infections based on microbiological approaches. The aim of this study was to identify potential biodiversity of bacterial species from infected native and prosthetic valves. Furthermore, we compared the ultrastructural micro-environments to detect the localization and distribution patterns of pathogens in IE. Using next-generation sequencing (NGS) of 16S rDNA, which allows analysis of the entire bacterial community within a single sample, we investigated the biodiversity of infectious bacterial species from resected native and prosthetic valves in a clinical cohort of 8 IE patients. Furthermore, we investigated the ultrastructural infected valve micro-environment by focused ion beam scanning electron microscopy (FIB-SEM). Biodiversity was detected in 7 of 8 resected heart valves. This comprised 13 bacterial genera and 16 species. In addition to 11 pathogens already described as being IE related, 5 bacterial species were identified as having a novel association. In contrast, valve and blood culture-based diagnosis revealed only 4 species from 3 bacterial genera and did not show any relevant antibiotic resistance. The antibiotics chosen on this basis for treatment, however, did not cover the bacterial spectra identified by our amplicon sequencing analysis in 4 of 8 cases. In addition to intramural distribution patterns of infective bacteria, intracellular localization with evidence of bacterial immune escape mechanisms was identified. The high frequency of polymicrobial infections, pathogen diversity, and intracellular persistence of common IE-causing bacteria may provide clues to help explain the persistent and devastating mortality rate observed for IE. Improved bacterial diagnosis by 16S rDNA NGS that increases the ability to tailor antibiotic therapy may

  6. Law and Behaviours in Social Dilemmas : Testing the Effect of Obligations on Cooperation

    NARCIS (Netherlands)

    Galbiati, R.; Vertova, P.

    2005-01-01

    Laws consist of two components: the 'obligations' they express and the 'incentives' designed to enforce them.In this paper we run a public good experiment to test whether or not obligations have any independent effect on cooperation in social dilemmas.The results show that, for given marginal

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

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Obligated service and breach of contract. 163.42 Section... breach of contract. (a) Obligated service. (1) Individuals completing forestry education programs with an... request for waiver. (b) Breach of contract. Any individual who has participated in and accepted financial...

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

    Science.gov (United States)

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

    2008-01-01

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

  9. Relation between Teachers' Demographic and Professional Profile and Their Attitude towards Ethical Obligations of Teaching Profession

    Science.gov (United States)

    Goswami, I; Ranjith, L.

    2010-01-01

    Teachers in higher education are not contrastingly different from the primary and secondary school teachers in terms of their ethical obligations to their stakeholders. However in higher education teachers' professionalism and their attitude towards ethical obligations are believed to be more important for ensuring quality education services. The…

  10. 18 CFR 37.5 - Obligations of Transmission Providers and Responsible Parties.

    Science.gov (United States)

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Obligations of Transmission Providers and Responsible Parties. 37.5 Section 37.5 Conservation of Power and Water Resources... ACCESS SAME-TIME INFORMATION SYSTEMS § 37.5 Obligations of Transmission Providers and Responsible Parties...

  11. 28 CFR 43.2 - Obligations of persons receiving care and treatment.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Obligations of persons receiving care and treatment. 43.2 Section 43.2 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) RECOVERY OF COST OF HOSPITAL AND MEDICAL CARE AND TREATMENT FURNISHED BY THE UNITED STATES § 43.2 Obligations of persons...

  12. The logic of actual obligation. An alternative approach to deontic logic

    NARCIS (Netherlands)

    Voorbraak, F.

    In this paper we develop a system of deontic logic (LAO, the logic of actual obligation) with a rather limited scope: we are, only interested in obligations as far as they: are relevant for deciding what actions actually ought to be done in a particular situation, given some normative system N.

  13. 29 CFR 4.177 - Discharging fringe benefit obligations by equivalent means.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Discharging fringe benefit obligations by equivalent means... CONTRACTS Compensation Standards Compliance with Compensation Standards § 4.177 Discharging fringe benefit obligations by equivalent means. (a) In general. (1) Section 2(a)(2) of the Act, which provides for fringe...

  14. 45 CFR 660.11 - What are the Director's obligations in interstate situations?

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false What are the Director's obligations in interstate... SCIENCE FOUNDATION INTERGOVERNMENTAL REVIEW OF THE NATIONAL SCIENCE FOUNDATION PROGRAMS AND ACTIVITIES § 660.11 What are the Director's obligations in interstate situations? (a) The Director is responsible...

  15. 45 CFR 660.5 - What is the Director's obligation with respect to Federal interagency coordination?

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false What is the Director's obligation with respect to... Welfare (Continued) NATIONAL SCIENCE FOUNDATION INTERGOVERNMENTAL REVIEW OF THE NATIONAL SCIENCE FOUNDATION PROGRAMS AND ACTIVITIES § 660.5 What is the Director's obligation with respect to Federal...

  16. Modeling and analysis of renewable energy obligations and technology bandings in the UK electricity market

    NARCIS (Netherlands)

    Gurkan, G.; Langestraat, R.

    In the UK electricity market, generators are obliged to produce part of their electricity with renewable energy resources in accordance with the Renewable Obligation Order. Since 2009 technology banding has been added, meaning that different technologies are rewarded with a different number of

  17. 29 CFR 500.60 - Farm labor contractors' recruitment, contractual and general obligations.

    Science.gov (United States)

    2010-07-01

    ... labor contractors' recruitment, contractual and general obligations. The Act imposes certain specific recruitment, contractual and general obligations on farm labor contractors and farm labor contractor employees... 29 Labor 3 2010-07-01 2010-07-01 false Farm labor contractors' recruitment, contractual and...

  18. 24 CFR 236.755 - Housing owner's obligation under contract to report tenant income increase.

    Science.gov (United States)

    2010-04-01

    ... FOR RENTAL PROJECTS Rental Assistance Payments § 236.755 Housing owner's obligation under contract to... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Housing owner's obligation under contract to report tenant income increase. 236.755 Section 236.755 Housing and Urban Development...

  19. Obligate brood parasites show more functionally effective innate immune responses: an eco-immunological hypothesis

    Science.gov (United States)

    Hahn, D. Caldwell; Summers, Scott G.; Genovese, Kenneth J.; He, Haiqi; Kogut, Michael H.

    2013-01-01

    Immune adaptations of obligate brood parasites attracted interest when three New World cowbird species (Passeriformes, Icteridae, genus Molothrus) proved unusually resistant to West Nile virus. We have used cowbirds as models to investigate the eco-immunological hypothesis that species in parasite-rich environments characteristically have enhanced immunity as a life history adaptation. As part of an ongoing program to understand the cowbird immune system, in this study we measured degranulation and oxidative burst, two fundamental responses of the innate immune system. Innate immunity provides non-specific, fast-acting defenses against a variety of invading pathogens, and we hypothesized that innate immunity experiences particularly strong selection in cowbirds, because their life history strategy exposes them to diverse novel and unpredictable parasites. We compared the relative effectiveness of degranulation and oxidative burst responses in two cowbird species and one related, non-parasitic species. Both innate immune defenses were significantly more functionally efficient in the two parasitic cowbird species than in the non-parasitic red-winged blackbird (Icteridae, Agelaius phoeniceus). Additionally, both immune defenses were more functionally efficient in the brown-headed cowbird (M. ater), an extreme host-generalist brood parasite, than in the bronzed cowbird (M. aeneus), a moderate host-specialist with lower exposure to other species and their parasites. Thus the relative effectiveness of these two innate immune responses corresponds to the diversity of parasites in the niche of each species and to their relative resistance to WNV. This study is the first use of these two specialized assays in a comparative immunology study of wild avian species.

  20. THEORETICAL ASPECTS REGARDING THE OBLIGATION AS PROVIDED BY THE ROMANIAN LEGISLATION AND THE DOCTRINE

    Directory of Open Access Journals (Sweden)

    Bogdan NAZAT

    2015-07-01

    Full Text Available Taking into consideration the latest amendments of the Romanian civil legislation performed through the Civil code of 2009, as further amended, I consider useful to provide the lecturers with a theoretical overview over one of the most important institution in our legal environment, i.e. the obligation. The analyse will start with an introduction comprising the definition of the obligation as provided by the Civil code aand the doctrina, will continue with the structure of the obligation and, further, will offer an overview of its sources, identifying, inter alia, the articles in the Civil code where such sources are regulated (e.g. contract, law. In the end, the paper will provide a doctrinaire classification of the obligation, outlining the main categories of the obligations.

  1. Observer perceptions of moral obligations in groups with a history of victimization.

    Science.gov (United States)

    Warner, Ruth H; Branscombe, Nyla R

    2012-07-01

    The authors investigated when observers assign contemporary group members moral obligations based on their group's victimization history. In Experiment 1, Americans perceived Israelis as obligated to help Sudanese genocide victims and as guiltworthy for not helping if reminded of the Holocaust and its descendants were linked to this history. In Experiment 2, participants perceived Israelis as more obligated to help and guiltworthy for not helping when the Holocaust was presented as a unique victimization event compared with when genocide was presented as pervasive. Experiments 3 and 4 replicated the effects of Experiment 1 with Cambodians as the victimized group. Experiment 5 demonstrated that participants perceived Cambodians as having more obligations under high just world threat compared with low just world threat. Perceiving victimized groups as incurring obligations is one just world restoration method of providing meaning to collective injustice.

  2. Mothers', fathers' and children's perceptions of parents' expectations about children's family obligations in nine countries.

    Science.gov (United States)

    Lansford, Jennifer E; Godwin, Jennifer; Alampay, Liane Peña; Uribe Tirado, Liliana Maria; Zelli, Arnaldo; Al-Hassan, Suha M; Bacchini, Dario; Bombi, Anna Silvia; Bornstein, Marc H; Chang, Lei; Deater-Deckard, Kirby; Di Giunta, Laura; Dodge, Kenneth A; Malone, Patrick S; Oburu, Paul; Pastorelli, Concetta; Skinner, Ann T; Sorbring, Emma; Tapanya, Sombat

    2016-10-01

    Children's family obligations involve assistance and respect that children are expected to provide to immediate and extended family members and reflect beliefs related to family life that may differ across cultural groups. Mothers, fathers and children (N = 1432 families) in 13 cultural groups in 9 countries (China, Colombia, Italy, Jordan, Kenya, Philippines, Sweden, Thailand and United States) reported on their expectations regarding children's family obligations and parenting attitudes and behaviours. Within families, mothers and fathers had more concordant expectations regarding children's family obligations than did parents and children. Parenting behaviours that were warmer, less neglectful and more controlling as well as parenting attitudes that were more authoritarian were related to higher expectations regarding children's family obligations between families within cultures as well as between cultures. These international findings advance understanding of children's family obligations by contextualising them both within families and across a number of diverse cultural groups in 9 countries. © 2015 International Union of Psychological Science.

  3. [The right to self-determination versus the obligation to protect one's health].

    Science.gov (United States)

    Höfling, Wolfram

    2009-01-01

    "Individual responsibility" and the abidance by any "health-related obligations" are key words of the present political and legal German healthcare debate. In the process of adjusting the German welfare state by focussing the ideal allocation of common health resources patients who do not meet their "health-related obligations" are thus expected to accept cutbacks in medical care services. However, from the perspective of constitutional law there is no "health-related obligation" deriving from the German constitution - the right to self-determination guaranteed in Art. 2 Sect. 2 Sent. 1 of the German constitution has not been amended to impose a corresponding duty. Hence, health-related obligations may only refer to indirect ways of exercising individual responsibility, no more and no less. The present article highlights the few possibilities which the German constitution provides for the implementation of "health-related obligations" and reminds us of the conceptual aspects which have to be considered by the legislator.

  4. Evolution of microbial pathogens.

    OpenAIRE

    Morschhäuser, J; Köhler, G; Ziebuhr, W; Blum-Oehler, G; Dobrindt, U; Hacker, J

    2000-01-01

    Various genetic mechanisms including point mutations, genetic rearrangements and lateral gene transfer processes contribute to the evolution of microbes. Long-term processes leading to the development of new species or subspecies are termed macroevolution, and short-term developments, which occur during days or weeks, are considered as microevolution. Both processes, macro- and microevolution need horizontal gene transfer, which is particularly important for the development of pathogenic micr...

  5. LIPID SYNTHESIS, INTRACELLULAR TRANSPORT, AND SECRETION

    Science.gov (United States)

    Stein, Olga; Stein, Yechezkiel

    1967-01-01

    In the mammary glands of lactating albino mice injected intravenously with 9, 10-oleic acid-3H or 9, 10-palmitic acid-3H, it has been shown that the labeled fatty acids are incorporated into mammary gland glycerides. The labeled lipid in the mammary gland 1 min after injection was in esterified form (> 95%), and the radioautographic reaction was seen over the rough endoplasmic reticulum and over lipid droplets, both intracellular and intraluminal. At 10–60 min after injection, the silver grains were concentrated predominantly over lipid droplets. There was no concentration of radioactivity over the granules in the Golgi apparatus, at any time interval studied. These findings were interpreted to indicate that after esterification of the fatty acid into glycerides in the rough endoplasmic reticulum an in situ aggregation of lipid occurs, with acquisition of droplet form. The release of the lipid into the lumen proceeds directly and not through the Golgi apparatus, in contradistinction to the mode of secretion of casein in the mammary gland or of lipoprotein in the liver. The presence of strands of endoplasmic reticulum attached to intraluminal lipid droplets provides a structural counterpart to the milk microsomes described in ruminant milk. PMID:6033535

  6. Endothelial remodelling and intracellular calcium machinery.

    Science.gov (United States)

    Moccia, F; Tanzi, F; Munaron, L

    2014-05-01

    Rather being an inert barrier between vessel lumen and surrounding tissues, vascular endothelium plays a key role in the maintenance of cardiovascular homeostasis. The de-endothelialization of blood vessels is regarded as the early event that results in the onset of severe vascular disorders, including atherosclerosis, acute myocardial infarction, brain stroke, and aortic aneurysm. Restoration of the endothelial lining may be accomplished by the activation of neighbouring endothelial cells (ECs) freed by contact inhibition and by circulating endothelial progenitor cells (EPCs). Intracellular Ca(2+) signalling is essential to promote wound healing: however, the molecular underpinnings of the Ca(2+) response to injury are yet to be fully elucidated. Similarly, the components of the Ca(2+) toolkit that drive EPC incorporation into denuded vessels are far from being fully elucidated. The present review will survey the current knowledge on the role of Ca(2+) signalling in endothelial repair and in EPC activation. We propose that endothelial regeneration might be boosted by intraluminal release of specific Ca(2+) channel agonists or by gene transfer strategies aiming to enhance the expression of the most suitable Ca(2+) channels at the wound site. In this view, connexin (Cx) channels/hemichannels and store-operated Ca(2+) entry (SOCE) stand amid the most proper routes to therapeutically induce the regrowth of denuded vessels. Cx stimulation might trigger the proliferative and migratory behaviour of ECs facing the lesion site, whereas activation of SOCE is likely to favour EPC homing to the wounded vessel.

  7. Intracellular events regulating cross-presentation

    Directory of Open Access Journals (Sweden)

    Peter eCresswell

    2012-06-01

    Full Text Available Cross-presentation plays a fundamental role in the induction of CD8-T cell immunity. However, although more than three decades have passed since its discovery, surprisingly little is known about the exact mechanisms involved. Here we give an overview of the components involved at different stages of this process. First, antigens must be internalized into the cross-presenting cell. The involvement of different receptors, method of antigen uptake, and nature of the antigen can influence intracellular trafficking and access to the cross-presentation pathway. Once antigens access the endocytic system, different requirements for endosomal/phagosomal processing arise, such as proteolysis and reduction of disulfide bonds. The majority of cross-presented peptides are generated by proteasomal degradation. Therefore, antigens must cross a membrane barrier in a manner analogous to the fate of misfolded proteins in the endoplasmic reticulum (ER that are retrotranslocated into the cytosol for degradation. Indeed, some components of the ER-associated degradation (ERAD machinery have been implicated in cross-presentation. Further complicating the matter, endosomal and phagosomal compartments have been suggested as alternative sites to the ER for loading of peptides on MHC class I molecules. Finally, the antigen presenting cells involved, particularly dendritic cell subsets and their state of maturation, influence the efficiency of cross-presentation.

  8. Intracellular recording from a spider vibration receptor.

    Science.gov (United States)

    Gingl, Ewald; Burger, Anna-M; Barth, Friedrich G

    2006-05-01

    The present study introduces a new preparation of a spider vibration receptor that allows intracellular recording of responses to natural mechanical or electrical stimulation of the associated mechanoreceptor cells. The spider vibration receptor is a lyriform slit sense organ made up of 21 cuticular slits located on the distal end of the metatarsus of each walking leg. The organ is stimulated when the tarsus receives substrate vibrations, which it transmits to the organ's cuticular structures, reducing the displacement to about one tenth due to geometrical reasons. Current clamp recording was used to record action potentials generated by electrical or mechanical stimuli. Square pulse stimulation identified two groups of sensory cells, the first being single-spike cells which generated only one or two action potentials and the second being multi-spike cells which produced bursts of action potentials. When the more natural mechanical sinusoidal stimulation was applied, differences in adaptation rate between the two cell types remained. In agreement with prior extracellular recordings, both cell types showed a decrease in the threshold tarsus deflection with increasing stimulus frequency. Off-responses to mechanical stimuli have also been seen in the metatarsal organ for the first time.

  9. On the Computing Potential of Intracellular Vesicles.

    Science.gov (United States)

    Mayne, Richard; Adamatzky, Andrew

    2015-01-01

    Collision-based computing (CBC) is a form of unconventional computing in which travelling localisations represent data and conditional routing of signals determines the output state; collisions between localisations represent logical operations. We investigated patterns of Ca2+-containing vesicle distribution within a live organism, slime mould Physarum polycephalum, with confocal microscopy and observed them colliding regularly. Vesicles travel down cytoskeletal 'circuitry' and their collisions may result in reflection, fusion or annihilation. We demonstrate through experimental observations that naturally-occurring vesicle dynamics may be characterised as a computationally-universal set of Boolean logical operations and present a 'vesicle modification' of the archetypal CBC 'billiard ball model' of computation. We proceed to discuss the viability of intracellular vesicles as an unconventional computing substrate in which we delineate practical considerations for reliable vesicle 'programming' in both in vivo and in vitro vesicle computing architectures and present optimised designs for both single logical gates and combinatorial logic circuits based on cytoskeletal network conformations. The results presented here demonstrate the first characterisation of intracelluar phenomena as collision-based computing and hence the viability of biological substrates for computing.

  10. Modeling HIV-1 intracellular replication: two simulation approaches

    NARCIS (Netherlands)

    Zarrabi, N.; Mancini, E.; Tay, J.; Shahand, S.; Sloot, P.M.A.

    2010-01-01

    Many mathematical and computational models have been developed to investigate the complexity of HIV dynamics, immune response and drug therapy. However, there are not many models which consider the dynamics of virus intracellular replication at a single level. We propose a model of HIV intracellular

  11. Intracellular Drug Bioavailability: Effect of Neutral Lipids and Phospholipids.

    Science.gov (United States)

    Treyer, Andrea; Mateus, André; Wiśniewski, Jacek R; Boriss, Hinnerk; Matsson, Pär; Artursson, Per

    2018-06-04

    Intracellular unbound drug concentrations are the pharmacologically relevant concentrations for targets inside cells. Intracellular drug concentrations are determined by multiple processes, including the extent of drug binding to intracellular structures. The aim of this study was to evaluate the effect of neutral lipid (NL) and phospholipid (PL) levels on intracellular drug disposition. The NL and/or PL content of 3T3-L1 cells were enhanced, resulting in phenotypes (in terms of morphology and proteome) reminiscent of adipocytes (high NL and PL) or mild phospholipidosis (only high PL). Intracellular bioavailability ( F ic ) was then determined for 23 drugs in these cellular models and in untreated wild-type cells. A higher PL content led to higher intracellular drug binding and a lower F ic . The induction of NL did not further increase drug binding but led to altered F ic due to increased lysosomal pH. Further, there was a good correlation between binding to beads coated with pure PL and intracellular drug binding. In conclusion, our results suggest that PL content is a major determinant of drug binding in cells and that PL beads may constitute a simple alternative to estimating this parameter. Further, the presence of massive amounts of intracellular NLs did not influence drug binding significantly.

  12. Analysis of Intracellular Metabolites from Microorganisms: Quenching and Extraction Protocols.

    Science.gov (United States)

    Pinu, Farhana R; Villas-Boas, Silas G; Aggio, Raphael

    2017-10-23

    Sample preparation is one of the most important steps in metabolome analysis. The challenges of determining microbial metabolome have been well discussed within the research community and many improvements have already been achieved in last decade. The analysis of intracellular metabolites is particularly challenging. Environmental perturbations may considerably affect microbial metabolism, which results in intracellular metabolites being rapidly degraded or metabolized by enzymatic reactions. Therefore, quenching or the complete stop of cell metabolism is a pre-requisite for accurate intracellular metabolite analysis. After quenching, metabolites need to be extracted from the intracellular compartment. The choice of the most suitable metabolite extraction method/s is another crucial step. The literature indicates that specific classes of metabolites are better extracted by different extraction protocols. In this review, we discuss the technical aspects and advancements of quenching and extraction of intracellular metabolite analysis from microbial cells.

  13. Analysis of Intracellular Metabolites from Microorganisms: Quenching and Extraction Protocols

    Directory of Open Access Journals (Sweden)

    Farhana R. Pinu

    2017-10-01

    Full Text Available Sample preparation is one of the most important steps in metabolome analysis. The challenges of determining microbial metabolome have been well discussed within the research community and many improvements have already been achieved in last decade. The analysis of intracellular metabolites is particularly challenging. Environmental perturbations may considerably affect microbial metabolism, which results in intracellular metabolites being rapidly degraded or metabolized by enzymatic reactions. Therefore, quenching or the complete stop of cell metabolism is a pre-requisite for accurate intracellular metabolite analysis. After quenching, metabolites need to be extracted from the intracellular compartment. The choice of the most suitable metabolite extraction method/s is another crucial step. The literature indicates that specific classes of metabolites are better extracted by different extraction protocols. In this review, we discuss the technical aspects and advancements of quenching and extraction of intracellular metabolite analysis from microbial cells.

  14. Systematic Identification of Intracellular-Translocated Candidate Effectors in Edwardsiella piscicida

    Directory of Open Access Journals (Sweden)

    Lingzhi Zhang

    2018-02-01

    Full Text Available Many bacterial pathogens inject effectors directly into host cells to target a variety of host cellular processes and promote bacterial dissemination and survival. Identifying the bacterial effectors and elucidating their functions are central to understanding the molecular pathogenesis of these pathogens. Edwardsiella piscicida is a pathogen with a wide host range, and very few of its effectors have been identified to date. Here, based on the genes significantly regulated by macrophage infection, we identified 25 intracellular translocation-positive candidate effectors, including all five previously reported effectors, namely EseG, EseJ, EseH, EseK, and EvpP. A subsequent secretion analysis revealed diverse secretion patterns for the 25 effector candidates, suggesting that multiple transport pathways were involved in the internalization of these candidate effectors. Further, we identified two novel type VI secretion system (T6SS putative effectors and three outer membrane vesicles (OMV-dependent putative effectors among the candidate effectors described above, and further analyzed their contribution to bacterial virulence in a zebrafish model. This work demonstrates an effective approach for screening bacterial effectors and expands the effectors repertoire in E. piscicida.

  15. Abalone farm discharges the withering syndrome pathogen into the wild

    Directory of Open Access Journals (Sweden)

    Kevin eLafferty

    2013-12-01

    Full Text Available An intracellular bacterium Candidatus Xenohaliotis californiensis, also called Withering-Syndrome Rickettsia-Like Organism (WS-RLO, is the cause of mass mortalities that are the chief reason for endangerment of black abalone (Haliotis cracherodii. Using a real-time PCR assay, we found that a shore-based abalone farm in Santa Barbara, California, discharged WS-RLO DNA into the ocean. Several other shore-based abalone farms discharge effluent into critical habitat for black abalone in California and this might affect the recovery of wild black abalone. Existing regulatory frameworks exist that could help protect wild species from pathogens released from shore-based aquaculture.

  16. Abalone farm discharges the withering syndrome pathogen into the wild.

    Science.gov (United States)

    Lafferty, Kevin D; Ben-Horin, Tal

    2013-01-01

    An intracellular bacterium Candidatus Xenohaliotis californiensis, also called Withering-Syndrome Rickettsia-Like Organism (WS-RLO), is the cause of mass mortalities that are the chief reason for endangerment of black abalone (Haliotis cracherodii). Using a real-time PCR assay, we found that a shore-based abalone farm (AF) in Santa Barbara, CA, USA discharged WS-RLO DNA into the ocean. Several other shore-based AFs discharge effluent into critical habitat for black abalone in California and this might affect the recovery of wild black abalone. Existing regulatory frameworks exist that could help protect wild species from pathogens released from shore-based aquaculture.

  17. Genomic and Phenomic Study of Mammary Pathogenic Escherichia coli

    Science.gov (United States)

    Blum, Shlomo E.; Heller, Elimelech D.; Sela, Shlomo; Elad, Daniel; Edery, Nir; Leitner, Gabriel

    2015-01-01

    Escherichia coli is a major etiological agent of intra-mammary infections (IMI) in cows, leading to acute mastitis and causing great economic losses in dairy production worldwide. Particular strains cause persistent IMI, leading to recurrent mastitis. Virulence factors of mammary pathogenic E. coli (MPEC) involved pathogenesis of mastitis as well as those differentiating strains causing acute or persistent mastitis are largely unknown. This study aimed to identify virulence markers in MPEC through whole genome and phenome comparative analysis. MPEC strains causing acute (VL2874 and P4) or persistent (VL2732) mastitis were compared to an environmental strain (K71) and to the genomes of strains representing different E. coli pathotypes. Intra-mammary challenge in mice confirmed experimentally that the strains studied here have different pathogenic potential, and that the environmental strain K71 is non-pathogenic in the mammary gland. Analysis of whole genome sequences and predicted proteomes revealed high similarity among MPEC, whereas MPEC significantly differed from the non-mammary pathogenic strain K71, and from E. coli genomes from other pathotypes. Functional features identified in MPEC genomes and lacking in the non-mammary pathogenic strain were associated with synthesis of lipopolysaccharide and other membrane antigens, ferric-dicitrate iron acquisition and sugars metabolism. Features associated with cytotoxicity or intra-cellular survival were found specifically in the genomes of strains from severe and acute (VL2874) or persistent (VL2732) mastitis, respectively. MPEC genomes were relatively similar to strain K-12, which was subsequently shown here to be possibly pathogenic in the mammary gland. Phenome analysis showed that the persistent MPEC was the most versatile in terms of nutrients metabolized and acute MPEC the least. Among phenotypes unique to MPEC compared to the non-mammary pathogenic strain were uric acid and D-serine metabolism. This study

  18. Medium pH in submerged cultivation modulates differences in the intracellular protein profile of Fusarium oxysporum.

    Science.gov (United States)

    da Rosa-Garzon, Nathália Gonsales; Laure, Hélen Julie; Souza-Motta, Cristina Maria de; Rosa, José César; Cabral, Hamilton

    2017-08-09

    Fusarium oxysporum is a filamentous fungus that damages a wide range of plants and thus causes severe crop losses. In fungal pathogens, the genes and proteins involved in virulence are known to be controlled by environmental pH. Here, we report the influence of culture-medium pH (5, 6, 7, and 8) on the production of degradative enzymes involved in the pathogenesis of F. oxysporum URM 7401 and on the 2D-electrophoresis profile of intracellular proteins in this fungus. F. oxysporum URM 7401 was grown in acidic, neutral, and alkaline culture media in a submerged bioprocess. After 96 hr, the crude extract was processed to enzyme activity assays, while the intracellular proteins were obtained from mycelium and analyzed using 2D electrophoresis and mass spectrometry. We note that the diversity of secreted enzymes was changed quantitatively in different culture-medium pH. Also, the highest accumulated biomass and the intracellular protein profile of F. oxysporum URM 7401 indicate an increase in metabolism in neutral-alkaline conditions. The differential profiles of secreted enzymes and intracellular proteins under the evaluated conditions indicate that the global protein content in F. oxysporum URM 7401 is modulated by extracellular pH.

  19. Intergenotypic replacement of lyssavirus matrix proteins demonstrates the role of lyssavirus M proteins in intracellular virus accumulation.

    Science.gov (United States)

    Finke, Stefan; Granzow, Harald; Hurst, Jose; Pollin, Reiko; Mettenleiter, Thomas C

    2010-02-01

    Lyssavirus assembly depends on the matrix protein (M). We compared lyssavirus M proteins from different genotypes for their ability to support assembly and egress of genotype 1 rabies virus (RABV). Transcomplementation of M-deficient RABV with M from European bat lyssavirus (EBLV) types 1 and 2 reduced the release of infectious virus. Stable introduction of the heterogenotypic M proteins into RABV led to chimeric viruses with reduced virus release and intracellular accumulation of virus genomes. Although the chimeras indicated genotype-specific evolution of M, rapid selection of a compensatory mutant suggested conserved mechanisms of lyssavirus assembly and the requirement for only few adaptive mutations to fit the heterogenotypic M to a RABV backbone. Whereas the compensatory mutant replicated to similar infectious titers as RABV M-expressing virus, ultrastructural analysis revealed that both nonadapted EBLV M chimeras and the compensatory mutant differed from RABV M expressing viruses in the lack of intracellular viruslike structures that are enveloped and accumulate in cisterna of the degranulated and dilated rough endoplasmic reticulum compartment. Moreover, all viruses were able to bud at the plasma membrane. Since the lack of the intracellular viruslike structures correlated with the type of M protein but not with the efficiency of virus release, we hypothesize that the M proteins of EBLV-1 and RABV differ in their target membranes for virus assembly. Although the biological function of intracellular assembly and accumulation of viruslike structures in the endoplasmic reticulum remain unclear, the observed differences could contribute to diverse host tropism or pathogenicity.

  20. Enoyl-Acyl Carrier Protein Reductase I (FabI) Is Essential for the Intracellular Growth of Listeria monocytogenes

    Science.gov (United States)

    Ericson, Megan E.; Frank, Matthew W.

    2016-01-01

    Enoyl-acyl carrier protein reductase catalyzes the last step in each elongation cycle of type II bacterial fatty acid synthesis and is a key regulatory protein in bacterial fatty acid synthesis. Genes of the facultative intracellular pathogen Listeria monocytogenes encode two functional enoyl-acyl carrier protein isoforms based on their ability to complement the temperature-sensitive growth phenotype of Escherichia coli strain JP1111 [fabI(Ts)]. The FabI isoform was inactivated by the FabI selective inhibitor AFN-1252, but the FabK isoform was not affected by the drug, as expected. Inhibition of FabI by AFN-1252 decreased endogenous fatty acid synthesis by 80% and lowered the growth rate of L. monocytogenes in laboratory medium. Robust exogenous fatty acid incorporation was not detected in L. monocytogenes unless the pathway was partially inactivated by AFN-1252 treatment. However, supplementation with exogenous fatty acids did not restore normal growth in the presence of AFN-1252. FabI inactivation prevented the intracellular growth of L. monocytogenes, showing that neither FabK nor the incorporation of host cellular fatty acids was sufficient to support the intracellular growth of L. monocytogenes. Our results show that FabI is the primary enoyl-acyl carrier protein reductase of type II bacterial fatty acid synthesis and is essential for the intracellular growth of L. monocytogenes. PMID:27736774

  1. TetR-dependent gene regulation in intracellular Listeria monocytogenes demonstrates the spatiotemporal surface distribution of ActA.

    Science.gov (United States)

    Schmitter, Sibylle; Fieseler, Lars; Klumpp, Jochen; Bertram, Ralph; Loessner, Martin J

    2017-08-01

    To enable specific and tightly controlled gene expression both in vitro and during the intracellular lifecycle of the pathogen Listeria monocytogenes, a TetR-dependent genetic induction system was developed. Highest concentration of cytoplasmic TetR and best repression of tetO-controlled genes was obtained by tetR expression from the synthetic promoter Pt 17 . Anhydrotetracycline (ATc) as inducer permitted concentration-dependent, fine-tuned expression of genes under control of the tetO operator and a suitable promoter. The actin-polymerizing ActA protein represents a major virulence factor of L. monocytogenes, required for actin-based motility and cell-to-cell spread in infected host cells. To be able to observe its spatial and temporal distribution on intracellular L. monocytogenes cells, conditional mutants featuring actA placed under TetR control were used to infect PtK2 epithelial cells. Following induction at different time intervals, the subsequent recruitment of actin by L. monocytogenes could be monitored. We found that cells displayed functional ActA after approximately 15 min, while formation of polarized actin tail was complete after 90-120 min. At this point, intracellular motility of the induced mutants was indistinguishable from wild-type bacteria. Interestingly, de novo ActA synthesis in intracellular Listeria also demonstrated the temporal, asymmetric redistribution of the membrane-anchored proteins from the lateral walls toward the cell poles. © 2017 John Wiley & Sons Ltd.

  2. THE PRE-CONTRACT OBLIGATIONS REGARDING THE FRANCHISING AGREEMENT

    Directory of Open Access Journals (Sweden)

    DAN-ALEXANDRU SITARU

    2013-05-01

    Full Text Available The current paper puts into context the Government Ordinance no. 52/1997 regarding franchising with the new concepts of the Civil Code. Thus, under the old Civil Code there were no specific regulations that could be applied to a pre-contractual obligation of the parties. During any negotiation, because the parties sent each other a series of offers, counter offers, and in the end decided whether to agree or not, some parts of a professional secret, know-how, or any other important information for one or both might be revealed to the other. Under international laws, such as the one in France, or by using internationally established unwritten law, such as the Franchising Model Contract by the International Chamber of Commerce and Arbitration in Paris, such a disclosure of important or secret information is protected from future unauthorized usage by any party or affiliate if the contract is not signed. In the view of the new Civil Code, this stage in the development of an agreement, not yet binding, is now regulated and protected.

  3. Facultative and obligate methanotrophs how to identify and differentiate them.

    Science.gov (United States)

    Dedysh, Svetlana N; Dunfield, Peter F

    2011-01-01

    Aerobic methanotrophs are metabolically unique bacteria that are able to utilize methane and some other C1-compounds as sole sources of carbon and energy. A defining characteristic of these organisms is the use of methane monooxygenase (MMO) enzymes to catalyze the oxidation of methane to methanol. For a long time, all methanotrophs were considered to be obligately methylotrophic, that is, unable to grow on compounds containing C-C bonds. This notion has recently been revised. Some members of the genera Methylocella, Methylocystis, and Methylocapsa are now known to be facultative methanotrophs, that is, capable of growing on methane as well as on some multicarbon substrates. The diagnosis of facultative methanotrophy in new isolates requires a great degree of caution since methanotrophic cultures are frequently contaminated by heterotrophic bacteria that survive on metabolic by-products of methanotrophs. The presence of only a few satellite cells in a culture may lead to false conclusions regarding substrate utilization, and several early reports of facultative methanotrophy are likely attributable to impure cultures. Another recurring mistake is the misidentification of nonmethanotrophic facultative methylotrophs as facultative methanotrophs. This chapter was prepared as an aid to avoid both kinds of confusion when examining methanotrophic isolates. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Qualité et obligations de résultats

    CERN Document Server

    Guthapfel, C

    1998-01-01

    Un contrat de maintenance peut appartenir à deux grands types ; ceux où la prestation est définie par son contenu ou par son résultat. Dans l'exemple retenu, le résultat est exprimé principalement en terme d'état de référence à maintenir ; ce qui nécessite de définir préalablement l'état requis par rapport aux besoins exprimés ou implicites et l'écart toléré d'où une meilleure définition du besoin. Cette approche qualité responsabilise de manière plus complète le contractant par une facilité accrue de mesurer la conformité au besoin et la preuve de manquements aux obligations contractuelles est plus aisée à établir. Il faut toutefois noter un décalage entre les besoins exprimés et ressentis et la difficulté d'apprécier objectivement les résultats, d'où la nécessité d'améliorer et de formaliser les relations client/fournisseur. C'est uniquement sur ces bases que le partenariat, condition indispensable de l'efficience, peut se développer et les besoins être satisfaits au m...

  5. A unique, highly conserved secretory invertase is differentially expressed by promastigote developmental forms of all species of the human pathogen, Leishmania

    Science.gov (United States)

    Lyda, Todd A.; Joshi, Manju B.; Andersen, John F.; Kelada, Andrew Y.; Owings, Joshua P.; Bates, Paul A.; Dwyer, Dennis M.

    2015-01-01

    Leishmania are protozoan pathogens of humans that exist as extracellular promastigotes in the gut of their sand fly vectors and as obligate intracellular amastigotes within phagolysosomes of infected macrophages. Between infectious blood meal feeds, sand flies take plant juice meals that contain sucrose and store these sugars in their crop. Such sugars are regurgitated into the sand fly anterior midgut where they impact the developing promastigote parasite population. In this report we showed that promastigotes of all Leishmania species secreted an invertase/sucrase enzyme during their growth in vitro. In contrast, neither L. donovani nor L. mexicana amastigotes possessed any detectable invertase activity. Importantly, no released/secreted invertase activity was detected in culture supernatants from either Trypanosoma brucei or Trypanosoma cruzi. Using HPLC, the L. donovani secretory invertase was isolated and subjected to amino acid sequencing. Subsequently, we used a molecular approach to identify the LdINV and LmexINV genes encoding the ~72 kDa invertases produced by these organisms. Interestingly, we identified high fidelity LdINV-like homologs in the genomes of all Leishmania sp. but none were present in either T. brucei or T. cruzi. Northern blot and RT-PCR analyses showed that these genes were developmentally/differentially expressed in promastigotes but not amastigotes of these parasites. Homologous transfection studies demonstrated that these genes in fact encoded the functional secretory invertases produced by these parasites. Cumulatively, our results suggest that these secretory enzymes play critical roles in the survival/growth/development and transmission of all Leishmania parasites within their sand fly vector hosts. PMID:25763714

  6. Imaging and controlling intracellular reactions: Lysosome transport as a function of diameter and the intracellular synthesis of conducting polymers

    Science.gov (United States)

    Payne, Christine

    2014-03-01

    Eukaryotic cells are the ultimate complex environment with intracellular chemical reactions regulated by the local cellular environment. For example, reactants are sequestered into specific organelles to control local concentration and pH, motor proteins transport reactants within the cell, and intracellular vesicles undergo fusion to bring reactants together. Current research in the Payne Lab in the School of Chemistry and Biochemistry at Georgia Tech is aimed at understanding and utilizing this complex environment to control intracellular chemical reactions. This will be illustrated using two examples, intracellular transport as a function of organelle diameter and the intracellular synthesis of conducting polymers. Using single particle tracking fluorescence microscopy, we measured the intracellular transport of lysosomes, membrane-bound organelles, as a function of diameter as they underwent transport in living cells. Both ATP-dependent active transport and diffusion were examined. As expected, diffusion scales with the diameter of the lysosome. However, active transport is unaffected suggesting that motor proteins are insensitive to cytosolic drag. In a second example, we utilize intracellular complexity, specifically the distinct micro-environments of different organelles, to carry out chemical reactions. We show that catalase, found in the peroxisomes of cells, can be used to catalyze the polymerization of the conducting polymer PEDOT:PSS. More importantly, we have found that a range of iron-containing biomolecules are suitable catalysts with different iron-containing biomolecules leading to different polymer properties. These experiments illustrate the advantage of intracellular complexity for the synthesis of novel materials.

  7. Functional and Expression Analyses of the Pneumocystis MAT Genes Suggest Obligate Sexuality through Primary Homothallism within Host Lungs

    Directory of Open Access Journals (Sweden)

    S. Richard

    2018-02-01

    Full Text Available Fungi of the genus Pneumocystis are obligate parasites that colonize mammals’ lungs and are host species specific. Pneumocystis jirovecii and Pneumocystis carinii infect, respectively, humans and rats. They can turn into opportunistic pathogens in immunosuppressed hosts, causing severe pneumonia. Their cell cycle is poorly known, mainly because of the absence of an established method of culture in vitro. It is thought to include both asexual and sexual phases. Comparative genomic analysis suggested that their mode of sexual reproduction is primary homothallism involving a single mating type (MAT locus encompassing plus and minus genes (matMc, matMi, and matPi; Almeida et al., mBio 6:e02250-14, 2015. Thus, each strain would be capable of sexual reproduction alone (self-fertility. However, this is a working hypothesis derived from computational analyses that is, in addition, based on the genome sequences of single isolates. Here, we tested this hypothesis in the wet laboratory. The function of the P. jirovecii and P. carinii matMc genes was ascertained by restoration of sporulation in the corresponding mutant of fission yeast. Using PCR, we found the same single MAT locus in all P. jirovecii isolates and showed that all three MAT genes are often concomitantly expressed during pneumonia. Extensive homology searches did not identify other types of MAT transcription factors in the genomes or cis-acting motifs flanking the MAT locus that could have been involved in MAT switching or silencing. Our observations suggest that Pneumocystis sexuality through primary homothallism is obligate within host lungs to complete the cell cycle, i.e., produce asci necessary for airborne transmission to new hosts.

  8. Intracellular Localization of Arabidopsis Sulfurtransferases1

    Science.gov (United States)

    Bauer, Michael; Dietrich, Christof; Nowak, Katharina; Sierralta, Walter D.; Papenbrock, Jutta

    2004-01-01

    Sulfurtransferases (Str) comprise a group of enzymes widely distributed in archaea, eubacteria, and eukaryota which catalyze the transfer of a sulfur atom from suitable sulfur donors to nucleophilic sulfur acceptors. In all organisms analyzed to date, small gene families encoding Str proteins have been identified. The gene products were localized to different compartments of the cells. Our interest concerns the localization of Str proteins encoded in the nuclear genome of Arabidopsis. Computer-based prediction methods revealed localization in different compartments of the cell for six putative AtStrs. Several methods were used to determine the localization of the AtStr proteins experimentally. For AtStr1, a mitochondrial localization was demonstrated by immunodetection in the proteome of isolated mitochondria resolved by one- and two-dimensional gel electrophoresis and subsequent blotting. The respective mature AtStr1 protein was identified by mass spectrometry sequencing. The same result was obtained by transient expression of fusion constructs with the green fluorescent protein in Arabidopsis protoplasts, whereas AtStr2 was exclusively localized to the cytoplasm by this method. Three members of the single-domain AtStr were localized in the chloroplasts as demonstrated by transient expression of green fluorescent protein fusions in protoplasts and stomata, whereas the single-domain AtStr18 was shown to be cytoplasmic. The remarkable subcellular distribution of AtStr15 was additionally analyzed by transmission electron immunomicroscopy using a monospecific antibody against green fluorescent protein, indicating an attachment to the thylakoid membrane. The knowledge of the intracellular localization of the members of this multiprotein family will help elucidate their specific functions in the organism. PMID:15181206

  9. Intracellular signaling by diffusion: can waves of hydrogen peroxide transmit intracellular information in plant cells?

    DEFF Research Database (Denmark)

    Vestergaard, Christian L.; Flyvbjerg, Henrik; Møller, Ian Max

    2012-01-01

    of the physical and biochemical conditions in plant cells. As model system, we use a H(2)O(2) signal originating at the plasma membrane (PM) and spreading through the cytosol. We consider two maximally simple types of signals, isolated pulses and harmonic oscillations. First we consider the basic limits......Amplitude- and frequency-modulated waves of Ca(2+) ions transmit information inside cells. Reactive Oxygen Species (ROS), specifically hydrogen peroxide, have been proposed to have a similar role in plant cells. We consider the feasibility of such an intracellular communication system in view...

  10. Duplications and losses in gene families of rust pathogens highlight putative effectors

    Directory of Open Access Journals (Sweden)

    Amanda L. Pendleton

    2014-06-01

    Full Text Available Rust fungi are a group of fungal pathogens that cause some of the world’s most destructive diseases of trees and crops. A shared characteristic among rust fungi is obligate biotrophy, the inability to complete a lifecycle without a host. This dependence on a host species likely affects patterns of gene expansion, contraction, and innovation within rust pathogen genomes. The establishment of disease by biotrophic pathogens is reliant upon effector proteins that are encoded in the fungal genome and secreted from the pathogen into the host’s cell apoplast or within the cells. This study uses a comparative genomic approach to elucidate putative effectors and determine their evolutionary histories. We used OrthoMCL to identify nearly 20,000 gene families in proteomes of sixteen diverse fungal species, which include fifteen basidiomycetes and one ascomycete. We inferred patterns of duplication and loss for each gene family and identified families with distinctive patterns of expansion/contraction associated with the evolution of rust fungal genomes. To recognize potential contributors for the unique features of rust pathogens, we identified families harboring secreted proteins that: i arose or expanded in rust pathogens relative to other fungi, or ii contracted or were lost in rust fungal genomes. While the origin of rust fungi appears to be associated with considerable gene loss, there are many gene duplications associated with each sampled rust fungal genome. We also highlight two putative effector gene families that have expanded in Cqf that we hypothesize have roles in pathogenicity.

  11. Duplications and losses in gene families of rust pathogens highlight putative effectors.

    Science.gov (United States)

    Pendleton, Amanda L; Smith, Katherine E; Feau, Nicolas; Martin, Francis M; Grigoriev, Igor V; Hamelin, Richard; Nelson, C Dana; Burleigh, J Gordon; Davis, John M

    2014-01-01

    Rust fungi are a group of fungal pathogens that cause some of the world's most destructive diseases of trees and crops. A shared characteristic among rust fungi is obligate biotrophy, the inability to complete a lifecycle without a host. This dependence on a host species likely affects patterns of gene expansion, contraction, and innovation within rust pathogen genomes. The establishment of disease by biotrophic pathogens is reliant upon effector proteins that are encoded in the fungal genome and secreted from the pathogen into the host's cell apoplast or within the cells. This study uses a comparative genomic approach to elucidate putative effectors and determine their evolutionary histories. We used OrthoMCL to identify nearly 20,000 gene families in proteomes of 16 diverse fungal species, which include 15 basidiomycetes and one ascomycete. We inferred patterns of duplication and loss for each gene family and identified families with distinctive patterns of expansion/contraction associated with the evolution of rust fungal genomes. To recognize potential contributors for the unique features of rust pathogens, we identified families harboring secreted proteins that: (i) arose or expanded in rust pathogens relative to other fungi, or (ii) contracted or were lost in rust fungal genomes. While the origin of rust fungi appears to be associated with considerable gene loss, there are many gene duplications associated with each sampled rust fungal genome. We also highlight two putative effector gene families that have expanded in Cqf that we hypothesize have roles in pathogenicity.

  12. Modeling and analysis of renewable energy obligations and technology bandings in the UK electricity market

    International Nuclear Information System (INIS)

    Gürkan, Gül; Langestraat, Romeo

    2014-01-01

    In the UK electricity market, generators are obliged to produce part of their electricity with renewable energy resources in accordance with the Renewable Obligation Order. Since 2009 technology banding has been added, meaning that different technologies are rewarded with a different number of certificates. We analyze these two different renewable obligation policies in a mathematical representation of an electricity market with random availabilities of renewable generation outputs and random electricity demand. We also present another, alternative, banding policy. We provide revenue adequate pricing schemes for the three obligation policies. We carry out a simulation study via sampling. A key finding is that the UK banding policy cannot guarantee that the original obligation target is met, hence potentially resulting in more pollution. Our alternative provides a way to make sure that the target is met while supporting less established technologies, but it comes with a significantly higher consumer price. Furthermore, as an undesirable side effect, we observe that a cost reduction in a technology with a high banding (namely offshore wind) leads to more CO 2 emissions under the UK banding policy and to higher consumer prices under the alternative banding policy. - Highlights: • We model and analyze three renewable obligation policies in a mathematical framework. • We provide revenue adequate pricing schemes for the three policies. • We carry out a simulation study via sampling. • The UK policy cannot guarantee that the original obligation target is met. • Cost reductions can lead to more pollution or higher prices under banding policies

  13. Energy supplier obligations and white certificate schemes: Comparative analysis of experiences in the European Union

    International Nuclear Information System (INIS)

    Bertoldi, Paolo; Rezessy, Silvia; Lees, Eoin; Baudry, Paul; Jeandel, Alexandre; Labanca, Nicola

    2010-01-01

    A number of Member States of the European Union (EU) have introduced market-based policy portfolios based on quantified energy savings obligations on energy distributors or suppliers, possibly coupled with certification of project-based energy savings (via white certificates), and the option to trade the certificates or obligations. The paper provides an up-to-date review and analysis of results to date of white certificate schemes in the EU. In the EU supplier obligations and white certificate schemes have delivered larger savings than originally expected with obliged companies exceeding targets and, in some cases, at cost below what policy makers have anticipated. Supplier obligations foster the uptake of standardised energy efficiency actions often targeting smaller energy users (residential sector), lowering the transaction costs and contributing to market transformation. The role of certificate trading is more ambiguous. Trading can bring benefits where the target is set sufficiently high with respect to the energy-saving potential in the sectors covered. Theoretically trading may be better suited for broader systems with comprehensive coverage, but even in smaller schemes trading may reduce the transaction costs of compliance for obliged actors without sufficient expertise on end-use energy efficiency. Yet, trading increases the administrative cost ratio of energy-saving obligations.

  14. The moral obligation to be vaccinated: utilitarianism, contractualism, and collective easy rescue.

    Science.gov (United States)

    Giubilini, Alberto; Douglas, Thomas; Savulescu, Julian

    2018-02-10

    We argue that individuals who have access to vaccines and for whom vaccination is not medically contraindicated have a moral obligation to contribute to the realisation of herd immunity by being vaccinated. Contrary to what some have claimed, we argue that this individual moral obligation exists in spite of the fact that each individual vaccination does not significantly affect vaccination coverage rates and therefore does not significantly contribute to herd immunity. Establishing the existence of a moral obligation to be vaccinated (both for adults and for children) despite the negligible contribution each vaccination can make to the realisation of herd immunity is important because such moral obligation would strengthen the justification for coercive vaccination policies. We show that two types of arguments-namely a utilitarian argument based on Parfit's Principle of Group Beneficence and a contractualist argument-can ground an individual moral obligation to be vaccinated, in spite of the imperceptible contribution that any single vaccination makes to vaccine coverage rates. We add a further argument for a moral obligation to be vaccinated that does not require embracing problematic comprehensive moral theories such as utilitarianism or contractualism. The argument is based on a "duty of easy rescue" applied to collectives, which grounds a collective moral obligation to realise herd immunity, and on a principle of fairness in the distribution of the burdens that must be borne to realise herd immunity.

  15. Energy supplier obligations and white certificate schemes: Comparative analysis of experiences in the European Union

    Energy Technology Data Exchange (ETDEWEB)

    Bertoldi, Paolo, E-mail: paolo.bertoldi@ec.europa.e [European Commission, Joint Research Centre, Institute for Energy, Via E. Fermi 1, TP 450, 21027 Ispra (Vatican City State, Holy See) (Italy); Rezessy, Silvia, E-mail: silvia.rezessy@ec.europa.e [European Commission, Joint Research Centre, Institute for Energy, Via E. Fermi 1, TP 450, 21027 Ispra (Vatican City State, Holy See) (Italy); Lees, Eoin, E-mail: eoin@eoinleesenergy.co [Eoin Lees Energy, 4 Silver Lane, West Challow, Wantage, Oxon OX12 9TX (United Kingdom); Baudry, Paul, E-mail: paul.baudry@edf.f [EDF R and D, Centre des Renardieres, 77818 Moret sur Loing (France); Jeandel, Alexandre, E-mail: alexandre.jeandel@gdfsuez.co [GDF SUEZ, 16, rue Ville L' Eveque, 75008 Paris (France); Labanca, Nicola, E-mail: nicola.labanca@polimi.i [eERG, Politecnico di Milano, Via Lambruschini n. 4, 20156 Milano (Italy)

    2010-03-15

    A number of Member States of the European Union (EU) have introduced market-based policy portfolios based on quantified energy savings obligations on energy distributors or suppliers, possibly coupled with certification of project-based energy savings (via white certificates), and the option to trade the certificates or obligations. The paper provides an up-to-date review and analysis of results to date of white certificate schemes in the EU. In the EU supplier obligations and white certificate schemes have delivered larger savings than originally expected with obliged companies exceeding targets and, in some cases, at cost below what policy makers have anticipated. Supplier obligations foster the uptake of standardised energy efficiency actions often targeting smaller energy users (residential sector), lowering the transaction costs and contributing to market transformation. The role of certificate trading is more ambiguous. Trading can bring benefits where the target is set sufficiently high with respect to the energy-saving potential in the sectors covered. Theoretically trading may be better suited for broader systems with comprehensive coverage, but even in smaller schemes trading may reduce the transaction costs of compliance for obliged actors without sufficient expertise on end-use energy efficiency. Yet, trading increases the administrative cost ratio of energy-saving obligations.

  16. The levels of disclosure relating to mine closure obligations by platinum mining companies

    Directory of Open Access Journals (Sweden)

    Joline Sturdy

    2017-06-01

    Aim: The aim of this study is to establish the extent to which platinum mines listed on the Johannesburg Stock Exchange (JSE comply with a recommended disclosure framework. Setting: South Africa is the largest producer of platinum in the world. The study covers all platinum mines listed on the JSE. Methods: Using a framework, a census of the annual financial statements, integrated annual reports and sustainability reports or websites was conducted to determine the level of compliance of disclosure relating to mine closure obligations to the recommended disclosure framework. Results: The results show disclosure relating to mine closure obligations of platinum mines listed on the JSE is inconsistent and not sufficient for stakeholders to understand the scope, key assumptions, parameters or reliability of the assessment and calculation of mine closure obligations. Conclusion: The assumptions used to determine mine closure obligations are specialised and multi-disciplinary. The accuracy and reliability of mine closure obligations will improve dramatically through greater transparency and access to information. It is recommended that the JSE listings for mining companies should require a competent person’s report to provide disclosure on assumptions, key values and processes applied to determine the mine closure obligations. Furthermore, it is recommended that the Department of Mineral Resources implements a mechanism of independent assessment of mine closure obligations by experts on an ongoing basis.

  17. Transience after disturbance: Obligate species recovery dynamics depend on disturbance duration.

    Science.gov (United States)

    Singer, Alexander; Johst, Karin

    2017-06-01

    After a disturbance event, population recovery becomes an important species response that drives ecosystem dynamics. Yet, it is unclear how interspecific interactions impact species recovery from a disturbance and which role the disturbance duration (pulse or press) plays. Here, we analytically derive conditions that govern the transient recovery dynamics from disturbance of a host and its obligately dependent partner in a two-species metapopulation model. We find that, after disturbance, species recovery dynamics depend on the species' role (i.e. host or obligately dependent species) as well as the duration of disturbance. Host recovery starts immediately after the disturbance. In contrast, for obligate species, recovery depends on disturbance duration. After press disturbance, which allows dynamics to equilibrate during disturbance, obligate species immediately start to recover. Yet, after pulse disturbance, obligate species continue declining although their hosts have already begun to increase. Effectively, obligate species recovery is delayed until a necessary host threshold occupancy is reached. Obligates' delayed recovery arises solely from interspecific interactions independent of dispersal limitations, which contests previous explanations. Delayed recovery exerts a two-fold negative effect, because populations continue declining to even smaller population sizes and the phase of increased risk from demographic stochastic extinction in small populations is prolonged. We argue that delayed recovery and its determinants -species interactions and disturbance duration - have to be considered in biodiversity management. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Misleading by Omission: Rethinking the Obligation to Inform Research Subjects about Funding Sources.

    Science.gov (United States)

    Manson, Neil C

    2017-11-15

    Informed consent requirements for medical research have expanded over the past half-century. The Declaration of Helsinki now includes an explicit positive obligation to inform subjects about funding sources. This is problematic in a number of ways and seems to oblige researchers to disclose information irrelevant to most consent decisions. It is argued here that such a problematic obligation involves an "informational fallacy." The aim in the second part of the paper is to provide a better approach to making sense of how a failure to inform about funding sources wrongs subjects: by making appeals to obligations to refrain from misleading by omission. This alternative approach-grounded in a general obligation to refrain from misleading, an obligation that is independent of informed consent-provides a basis for a norm that protects subjects' interests, without the informational fallacy. The approach developed here avoids the problems identified with the currently specified general obligation to inform about funding sources. © The Author 2017. Published by Oxford University Press, on behalf of the Journal of Medicine and Philosophy Inc. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. Filial anxiety and sense of obligation among offspring of Holocaust survivors.

    Science.gov (United States)

    Shrira, Amit; Menashe, Ravit; Bensimon, Moshe

    2018-03-13

    Much is known about adult children caring for their aging parents, yet the potentially unique experience of offspring caring for traumatized parents is underexplored. Therefore, the current studies assessed filial anxiety and sense of obligation among offspring of Holocaust survivors (OHS) in caring for their parents. In Study 1, we interviewed 10 OHS (mean age = 61.0) in order to extract themes of filial anxiety. Based on Study 1's data, a newly constructed scale of filial anxiety was administered in Study 2 to 59 adult offspring (mean age = 56.4): 28 OHS and 31 comparisons. Study 3 included 143 dyads of parents and offspring (mean age = 55.4 and 81.7, respectively): 86 Holocaust dyads and 57 comparison dyads. Parents reported posttraumatic stress disorder (PTSD) symptoms and offspring reported filial anxiety and sense of obligation. In Study 1, interviewees referred to concerns about parent experiencing decline alongside caregiving difficulties. In Study 2, OHS reported higher filial anxiety and sense of obligation relative to comparisons. This group difference was mediated by sense of obligation. In Study 3, OHS with parental PTSD reported higher filial anxiety and sense of obligation relative to comparisons. Once more, filial sense of obligation served as a mediator. In Studies 2-3, results remained significant after adjusting for offspring symptoms. Parental exposure to the Holocaust, and especially parental PTSD, related to higher filial obligation, which in turn was related to higher filial anxiety. These findings bear important implications for practitioners working with survivors' families.

  20. The 'special obligations' of the modern Hippocratic Oath for 21st century medicine.

    Science.gov (United States)

    Holmboe, Eric; Bernabeo, Elizabeth

    2014-01-01

    Profound advances and discoveries in medicine have markedly improved the lives of many over the 50 years since the modern Hippocratic Oath was written. Regrettably, these advances were and continue to be implemented suboptimally and inequitably across the globe. 'Special obligations to all my fellow humans' is an important theme of the modern Oath. From this perspective, we reflect on the special obligations of the medical profession, and examine how these obligations have changed over the past 50 years. We draw from perspectives of the social contract, professionalism, quality improvement, patient safety and a group of 31 international colleagues involved in medical education as we examine these obligations for individual doctors, health care institutions and medical education systems. The perspectives of the 31 clinician-educators helped us to situate the meaning of the theme of 'special obligations' in the context of challenges facing medical education and health care in the 21st century. Improving the quality of care and patient safety, and reducing health care disparities are now paramount as 'special obligations' for doctors, health care systems and medical education organisations, and require us to work collectively and collaboratively in an increasingly interconnected world. In our view, traditions such as the Hippocratic Oath will be worthy of public support only when the medical profession demonstrates in meaningful and transparent ways that it is meeting its social and civic obligations to make the world, not just health care, a better place. © 2013 John Wiley & Sons Ltd.

  1. Intracellular invasion of Orientia tsutsugamushi activates inflammasome in asc-dependent manner.

    Directory of Open Access Journals (Sweden)

    Jung-Eun Koo

    Full Text Available 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-1β (IL-1β, 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-1β 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-1β and activation of caspase-1 are ASC- and caspase-1- dependent since IL-1β 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-1β production, which is a critical innate immune response for effective host defense.

  2. Hamiltonella defensa, genome evolution of protective bacterial endosymbiont from pathogenic ancestors.

    Science.gov (United States)

    Degnan, Patrick H; Yu, Yeisoo; Sisneros, Nicholas; Wing, Rod A; Moran, Nancy A

    2009-06-02

    Eukaryotes engage in a multitude of beneficial and deleterious interactions with bacteria. Hamiltonella defensa, an endosymbiont of aphids and other sap-feeding insects, protects its aphid host from attack by parasitoid wasps. Thus H. defensa is only conditionally beneficial to hosts, unlike ancient nutritional symbionts, such as Buchnera, that are obligate. Similar to pathogenic bacteria, H. defensa is able to invade naive hosts and circumvent host immune responses. We have sequenced the genome of H. defensa to identify possible mechanisms that underlie its persistence in healthy aphids and protection from parasitoids. The 2.1-Mb genome has undergone significant reduction in size relative to its closest free-living relatives, which include Yersinia and Serratia species (4.6-5.4 Mb). Auxotrophic for 8 of the 10 essential amino acids, H. defensa is reliant upon the essential amino acids produced by Buchnera. Despite these losses, the H. defensa genome retains more genes and pathways for a variety of cell structures and processes than do obligate symbionts, such as Buchnera. Furthermore, putative pathogenicity loci, encoding type-3 secretion systems, and toxin homologs, which are absent in obligate symbionts, are abundant in the H. defensa genome, as are regulatory genes that likely control the timing of their expression. The genome is also littered with mobile DNA, including phage-derived genes, plasmids, and insertion-sequence elements, highlighting its dynamic nature and the continued role horizontal gene transfer plays in shaping it.

  3. 34 CFR 611.44 - Under what circumstances may the Secretary defer a scholarship recipient's service obligation?

    Science.gov (United States)

    2010-07-01

    ... a scholarship recipient's service obligation? (a) Upon written request, the Secretary may defer a service obligation for a scholarship recipient who— (1) Has not begun teaching in a high-need school of a... scholarship recipient's service obligation? 611.44 Section 611.44 Education Regulations of the Offices of the...

  4. 41 CFR 102-75.950 - Who has the responsibility for paying property-related obligations pending transfer or disposal...

    Science.gov (United States)

    2010-07-01

    ... responsibility for paying property-related obligations pending transfer or disposal of the property? 102-75.950... property-related obligations pending transfer or disposal of the property? Except as otherwise provided in... or other property-related obligations pending transfer or disposal of the property. Decontamination ...

  5. Insect symbiotic bacteria harbour viral pathogens for transovarial transmission.

    Science.gov (United States)

    Jia, Dongsheng; Mao, Qianzhuo; Chen, Yong; Liu, Yuyan; Chen, Qian; Wu, Wei; Zhang, Xiaofeng; Chen, Hongyan; Li, Yi; Wei, Taiyun

    2017-03-06

    Many insects, including mosquitoes, planthoppers, aphids and leafhoppers, are the hosts of bacterial symbionts and the vectors for transmitting viral pathogens 1-3 . In general, symbiotic bacteria can indirectly affect viral transmission by enhancing immunity and resistance to viruses in insects 3-5 . Whether symbiotic bacteria can directly interact with the virus and mediate its transmission has been unknown. Here, we show that an insect symbiotic bacterium directly harbours a viral pathogen and mediates its transovarial transmission to offspring. We observe rice dwarf virus (a plant reovirus) binding to the envelopes of the bacterium Sulcia, a common obligate symbiont of leafhoppers 6-8 , allowing the virus to exploit the ancient oocyte entry path of Sulcia in rice leafhopper vectors. Such virus-bacterium binding is mediated by the specific interaction of the viral capsid protein and the Sulcia outer membrane protein. Treatment with antibiotics or antibodies against Sulcia outer membrane protein interferes with this interaction and strongly prevents viral transmission to insect offspring. This newly discovered virus-bacterium interaction represents the first evidence that a viral pathogen can directly exploit a symbiotic bacterium for its transmission. We believe that such a model of virus-bacterium communication is a common phenomenon in nature.

  6. Amixicile, a novel strategy for targeting oral anaerobic pathogens.

    Science.gov (United States)

    Hutcherson, Justin A; Sinclair, Kathryn M; Belvin, Benjamin R; Gui, Qin; Hoffman, Paul S; Lewis, Janina P

    2017-09-05

    The oral microflora is composed of both health-promoting as well as disease-initiating bacteria. Many of the disease-initiating bacteria are anaerobic and include organisms such as Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Tannerella forsythia. Here we investigated a novel therapeutic, amixicile, that targets pyruvate:ferredoxin oxidoreductase (PFOR), a major metabolic enzyme involved in energy generation through oxidative decarboxylation of pyruvate. PFOR is present in these anaerobic pathogenic bacteria and thus we hypothesized that amixicile would effectively inhibit their growth. In general, PFOR is present in all obligate anaerobic bacteria, while oral commensal aerobes, including aerotolerant ones, such as Streptococcus gordonii, use pyruvate dehydrogenase to decarboxylate pyruvate. Accordingly, we observed that growth of the PFOR-containing anaerobic periodontal pathogens, grown in both monospecies as well as multispecies broth cultures was inhibited in a dose-dependent manner while that of S. gordonii was unaffected. Furthermore, we also show that amixicile is effective against these pathogens grown as monospecies and multispecies biofilms. Finally, amixicile is the first selective therapeutic agent active against bacteria internalized by host cells. Together, the results show that amixicile is an effective inhibitor of oral anaerobic bacteria and as such, is a good candidate for treatment of periodontal diseases.

  7. Genomic Analysis of Pathogenicity Determinants in Mycobacterium kansasii Type I

    KAUST Repository

    Guan, Qingtian

    2016-05-01

    Mycobacteria, a genus within Actinobacteria Phylum, are well known for two pathogens that cause human diseases: leprosy and tuberculosis. Other than the obligate human mycobacteria, there is a group of bacteria that are present in the environment and occasionally cause diseases in immunocompromised persons: the non-tuberculosis mycobacteria (NTM). Mycobacterium kansasii, which was first discovered in the Kansas state, is the main etiologic agent responsible for lung infections caused by NTM and raises attention because of its co-infection with human immunodeficiency virus (HIV). Five subspecies of M. kansasii (Type I-V) were described and only M. kansasii Type I is pathogenic to humans. M. kansasii is a Gram-positive bacteria that has a unique cell wall and secretion system, which is essential for its pathogenicity. We undertook a comparative genomics and transcriptomic approach to identify components of M. kansasii Type I pathogenicity. Our previous study showed that espA (ESX-1 essential protein) operon, a major component of the secretion system, is exclusively present in M. kansasii Type I. The purpose of this study was to test the functional role of the espA operon in pathogenicity and identify other components that may also be involved in pathogenicity. This study provides a new molecular diagnostic method for M. kansasii Type I infection using PCR (Polymerase Chain Reaction) technique to target the espAoperon. With detailed manual curation of the comparative genomics datasets, we found several genes exclusively present in M. kansasii Type I including ppsA/ppsC and whiB6, that we believe are involved, or have an effect on ESX-mediated secretion system. We have also highlighted, in our study, the differences in genetic components coding for the cell membrane composition between the five subspecies of M. kansasii. These results shed light on genetic components that are responsible for pathogenicity determinants in Type I M. kansasii and may help to design better

  8. New perspective in the assessment of total intracellular magnesium

    Directory of Open Access Journals (Sweden)

    Azzurra Sargenti

    2014-01-01

    Full Text Available Magnesium (Mg is essential for biological processes, but its cellular homeostasis has not been thoroughly elucidated, mainly because of the inadequacy of the available techniques to map intracellular Mg distribution. Recently, particular interest has been raised by a new family of fluorescent probes, diaza-18-crown-hydroxyquinoline (DCHQ, that shows remarkably high affinity and specificity for Mg, thus permitting the detection of the total intracellular Mg. The data obtained by fluori- metric and cytofluorimetric assays performed with DCHQ5 are in good agreement with atomic absorption spectroscopy, confirming that DCHQ5 probe allows both qualitative and quantitative determination of total intracellular Mg.

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

    International Nuclear Information System (INIS)

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

    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) has recently been described in T.gondii, which could potentially protect extracellular tachyzoites against salt and other ionic stresses. Here, we report the molecular characterization of the vacuolar type Na + /H + exchanger in T. gondii, TgNHE3, and its co-localization with the PLV/VAC proton-pyrophosphatase (TgVP1). We have created a TgNHE3 knockout strain, which is more sensitive to hyperosmotic shock and toxic levels of sodium, possesses a higher intracellular Ca 2+ concentration [Ca 2+ ] i , and exhibits a reduced host invasion efficiency. The defect in invasion correlates with a measurable reduction in the secretion of the adhesin TgMIC2. Overall, our results suggest that the PLV/VAC has functions analogous to those of the vacuolar compartments of plants and yeasts, providing the parasite with a mechanism to resist ionic fluctuations and, potentially, regulate protein trafficking.

  10. INTRACELLULAR Leishmania amazonensis KILLING INDUCED BY THE GUANINE NUCLEOSIDE 8-BROMOGUANOSINE

    Directory of Open Access Journals (Sweden)

    GIORGIO Selma

    1998-01-01

    Full Text Available In this study we investigated the effect of 8-Bromoguanosine, an immunostimulatory compound, on the cytotoxicity of macrophages against Leishmania amazonensis in an in vitro system. The results showed that macrophages treated with 8-Bromoguanosine before or after infection are capable to reduce parasite load, as monitored by the number of amastigotes per macrophage and the percentage of infected cells (i.e. phagocytic index. Since 8-Bromoguanosine was not directly toxic to the promastigotes, it was concluded that the ribonucleoside induced macrophage activation. Presumably, 8-Bromoguanosine primed macrophages by inducing interferon alpha and beta which ultimately led to L. amazonensis amastigote killing. The results suggest that guanine ribonucleosides may be useful to treat infections with intracellular pathogens.

  11. Resistance to cereal rusts at the plant cell wall - what can we learn from other host-pathogen systems?

    NARCIS (Netherlands)

    Collins, N.C.; Niks, R.E.; Schulze-Lefert, P.

    2007-01-01

    The ability of plant cells to resist invasion by pathogenic fungi at the cell periphery (pre-invasion resistance) differs from other types of resistance that are generally triggered after parasite entry and during differentiation of specialised intracellular feeding structures. Genetic sources of

  12. Biatriosporin D displays anti-virulence activity through decreasing the intracellular cAMP levels

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ming; Chang, Wenqiang; Shi, Hongzhuo; Zhou, Yanhui; Zheng, Sha; Li, Ying; Li, Lin; Lou, Hongxiang, E-mail: louhongxiang@sdu.edu.cn

    2017-05-01

    Candidiasis has long been a serious human health problem, and novel antifungal approaches are greatly needed. During both superficial and systemic infection, C. albicans relies on a battery of virulence factors, such as adherence, filamentation, and biofilm formation. In this study, we found that a small phenolic compound, Biatriosporin D (BD), isolated from an endolichenic fungus, Biatriospora sp., displayed anti-virulence activity by inhibiting adhesion, hyphal morphogenesis and biofilm formation of C. albicans. Of note is the high efficacy of BD in preventing filamentation with a much lower dose than its MIC value. Furthermore, BD prolonged the survival of worms infected by C. albicans in vivo. Quantitative real-time PCR analysis, exogenous cAMP rescue experiments and intracellular cAMP measurements revealed that BD regulates the Ras1-cAMP-Efg1 pathway by reducing cAMP levels to inhibit the hyphal formation. Further investigation showed that BD could upregulate Dpp3 to synthesize much more farnesol, which could inhibit the activity of Cdc35 and reduce the generation of cAMP. Taken together, these findings indicate that BD stimulates the expression of Dpp3 to synthesize more farnesol that directly inhibits the Cdc35 activity, reducing intracellular cAMP and thereby disrupting the morphologic transition and attenuating the virulence of C. albicans. Our study uncovers the underlying mechanism of BD as a prodrug in fighting against pathogenic C. albicans and provides a potential application of BD in fighting clinically relevant fungal infections by targeting fungal virulence. - Highlights: • BD inhibits the filamentation of C. albicans in multiple hypha-inducing conditions. • BD can prolong the survival of nematodes infected by C. albicans. • BD stimulates the expression of Dpp3 to synthesize more farnesol. • BD reduces intracellular cAMP and regulates Ras1-cAMP-PKA pathway.

  13. Biatriosporin D displays anti-virulence activity through decreasing the intracellular cAMP levels

    International Nuclear Information System (INIS)

    Zhang, Ming; Chang, Wenqiang; Shi, Hongzhuo; Zhou, Yanhui; Zheng, Sha; Li, Ying; Li, Lin; Lou, Hongxiang

    2017-01-01

    Candidiasis has long been a serious human health problem, and novel antifungal approaches are greatly needed. During both superficial and systemic infection, C. albicans relies on a battery of virulence factors, such as adherence, filamentation, and biofilm formation. In this study, we found that a small phenolic compound, Biatriosporin D (BD), isolated from an endolichenic fungus, Biatriospora sp., displayed anti-virulence activity by inhibiting adhesion, hyphal morphogenesis and biofilm formation of C. albicans. Of note is the high efficacy of BD in preventing filamentation with a much lower dose than its MIC value. Furthermore, BD prolonged the survival of worms infected by C. albicans in vivo. Quantitative real-time PCR analysis, exogenous cAMP rescue experiments and intracellular cAMP measurements revealed that BD regulates the Ras1-cAMP-Efg1 pathway by reducing cAMP levels to inhibit the hyphal formation. Further investigation showed that BD could upregulate Dpp3 to synthesize much more farnesol, which could inhibit the activity of Cdc35 and reduce the generation of cAMP. Taken together, these findings indicate that BD stimulates the expression of Dpp3 to synthesize more farnesol that directly inhibits the Cdc35 activity, reducing intracellular cAMP and thereby disrupting the morphologic transition and attenuating the virulence of C. albicans. Our study uncovers the underlying mechanism of BD as a prodrug in fighting against pathogenic C. albicans and provides a potential application of BD in fighting clinically relevant fungal infections by targeting fungal virulence. - Highlights: • BD inhibits the filamentation of C. albicans in multiple hypha-inducing conditions. • BD can prolong the survival of nematodes infected by C. albicans. • BD stimulates the expression of Dpp3 to synthesize more farnesol. • BD reduces intracellular cAMP and regulates Ras1-cAMP-PKA pathway.

  14. MTOR-Driven Metabolic Reprogramming Regulates Legionella pneumophila Intracellular Niche Homeostasis

    Science.gov (United States)

    Abshire, Camille F.; Roy, Craig R.

    2016-01-01

    Vacuolar bacterial pathogens are sheltered within unique membrane-bound organelles that expand over time to support bacterial replication. These compartments sequester bacterial molecules away from host cytosolic immunosurveillance pathways that induce antimicrobial responses. The mechanisms by which the human pulmonary pathogen Legionella pneumophila maintains niche homeostasis are poorly understood. We uncovered that the Legionella-containing vacuole (LCV) required a sustained supply of host lipids during expansion. Lipids shortage resulted in LCV rupture and initiation of a host cell death response, whereas excess of host lipids increased LCVs size and housing capacity. We found that lipids uptake from serum and de novo lipogenesis are distinct redundant supply mechanisms for membrane biogenesis in Legionella-infected macrophages. During infection, the metabolic checkpoint kinase Mechanistic Target of Rapamycin (MTOR) controlled lipogenesis through the Serum Response Element Binding Protein 1 and 2 (SREBP1/2) transcription factors. In Legionella-infected macrophages a host-driven response that required the Toll-like receptors (TLRs) adaptor protein Myeloid differentiation primary response gene 88 (Myd88) dampened MTOR signaling which in turn destabilized LCVs under serum starvation. Inactivation of the host MTOR-suppression pathway revealed that L. pneumophila sustained MTOR signaling throughout its intracellular infection cycle by a process that required the upstream regulator Phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) and one or more Dot/Icm effector proteins. Legionella-sustained MTOR signaling facilitated LCV expansion and inhibition of the PI3K-MTOR-SREPB1/2 axis through pharmacological or genetic interference or by activation of the host MTOR-suppression response destabilized expanding LCVs, which in turn triggered cell death of infected macrophages. Our work identified a host metabolic requirement for LCV homeostasis and demonstrated that L

  15. Global War on Terrorism: Reported Obligations for the Department of Defense

    National Research Council Canada - National Science Library

    Pickup, Sharon

    2008-01-01

    ... based on DOD's monthly Supplemental and Cost of War Execution Reports. This report, which responds to this requirement, contains our analysis of DOD's reported obligations for military operations in support of GWOT through September 2008...

  16. The National Guard Meeting Its Obligation to Provide Capable Forces for Homeland Security

    National Research Council Canada - National Science Library

    Sellars, Thomas J

    2006-01-01

    ... (warfighting versus domestic support/homeland security) be harmonized to best posture the Guard to meet both its state obligations and at the same time continue to play a pivotal role in joint warfighting and stability operations...

  17. 31 CFR 203.6 - Obligations of TT&L depositaries.

    Science.gov (United States)

    2010-07-01

    ... TREASURY TAX AND LOAN PROGRAM General Information § 203.6 Obligations of TT&L depositaries. A TT&L depositary must: (a) Administer a TIP main account balance, SDI account balance, or TIO account balance, as...

  18. 28 CFR 811.6 - Duration of the obligation to register.

    Science.gov (United States)

    2010-07-01

    ... section. (c) Reversal, vacation, or pardon. A person's obligation to register terminates if the person's conviction, finding of not guilty by reason of insanity, or finding that the person is a sexual psychopath is...

  19. Unliquidated Obligations for Air Force-Funded Projects Administered by The Naval Facilities Engineering Command

    National Research Council Canada - National Science Library

    2001-01-01

    ... consolidated financial statements. The Air Force Audit Agency requested us to assist in its review of the Statement of Budgetary Resources for the Air Force General Fund by reviewing unliquidated obligations for Air Force-funded...

  20. Obligations to power supply and Antitrust Law of the European Community; Strombezugsverpflichtungen und EG-Kartellverbot

    Energy Technology Data Exchange (ETDEWEB)

    Lerch, Dirk

    2008-07-01

    In the European electricity supply industry, a change to competition-oriented national markets under development of a common European electricity market is observed for some years. Under this aspect, the author of the contribution under consideration reports on obligations to the current power supply and on the trust prohibition in the European Community. The contribution under consideration consists of the following three chapters: (a) Discussion of fundamental questions regarding to cartel legal evaluation of obligations to power supply; (b) Conditions of the art. 81 sect. 1 EEC and application to obligations for power supply; (c) Exemption from the obligation to power supply according to art. 1 sect. 3 EEC. In particular, the regulation of the group exemption for vertical agreements of 22nd December, 1999, is considered.

  1. 12 CFR 611.1270 - Repayment of obligations-terminating bank.

    Science.gov (United States)

    2010-01-01

    ...-wide obligations in a method that we deem acceptable. Before we make a final decision on your proposal... respect to financing and disclosure. (2) If you and the other Farm Credit banks are unable to reach...

  2. The Law Applicable to Contractual Obligations: The Rome I Regulation in Comparative Perspective

    OpenAIRE

    De Miguel Asensio, Pedro Alberto

    2014-01-01

    The Law Applicable to Contractual Obligations: The Rome I Regulation in Comparative Perspective I. Introduction II. Party Autonomy III. Applicable Law in the Absence of Choice IV. Protection of Weaker Parties V. Overriding Mandatory Rules and Public Policy

  3. Controls Over Unliquidated Obligations in the Iraq Relief and Reconstruction Fund

    National Research Council Canada - National Science Library

    Bowen, Stuart W

    2007-01-01

    ...) are the major recipients of IRRF funds. Obligations are recorded when an authorized agent of the federal government enters into a legally binding agreement to purchase specific goods or services...

  4. BRIEF CONSIDERATIONS REGARDING THE PROPERTY TRANSFERRING OR ENGENDERING OF OBLIGATIONS CHARACTER OF THE SALES CONTRACT

    Directory of Open Access Journals (Sweden)

    Vlad-Victor OCHEA

    2016-05-01

    Full Text Available I herein want to emphasize the main aspects regarding the property/real estate transferring or engendering of obligations character of the sales contract governed by the Romanian Civil Code of 2009.

  5. Inclusive governance: the role of knowledge in fulfilling the obligations of citizens

    CSIR Research Space (South Africa)

    Karar, E

    2016-08-01

    Full Text Available Inclusive governance and citizen engagement in governing water is important in enhancing service delivery. Good citizens endorse their obligations alongside their respective rights. To date, much focus has been on the rights approach to fulfil basic...

  6. The β-hemolysin and intracellular survival of Streptococcus agalactiae in human macrophages.

    Science.gov (United States)

    Sagar, Anubha; Klemm, Carolin; Hartjes, Lara; Mauerer, Stefanie; van Zandbergen, Ger; Spellerberg, Barbara

    2013-01-01

    S. agalactiae (group B streptococci, GBS) is a major microbial pathogen in human neonates and causes invasive infections in pregnant women and immunocompromised individuals. The S. agalactiae β-hemolysin is regarded as an important virulence factor for the development of invasive disease. To examine the role of β-hemolysin in the interaction with professional phagocytes, the THP-1 monocytic cell line and human granulocytes were infected with a serotype Ia S. agalactiae wild type strain and its isogenic nonhemolytic mutant. We could show that the nonhemolytic mutants were able to survive in significantly higher numbers than the hemolytic wild type strain, in THP-1 macrophage-like cells and in assays with human granulocytes. Intracellular bacterial multiplication, however, could not be observed. The hemolytic wild type strain stimulated a significantly higher release of Tumor Necrosis Factor-α than the nonhemolytic mutant in THP-1 cells, while similar levels of the chemokine Interleukin-8 were induced. In order to investigate bacterial mediators of IL-8 release in this setting, purified cell wall preparations from both strains were tested and found to exert a potent proinflammatory stimulus on THP-1 cells. In conclusion, our results indicate that the β-hemolysin has a strong influence on the intracellular survival of S. agalactiae and that a tightly controlled regulation of β-hemolysin expression is required for the successful establishment of S. agalactiae in different host niches.

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

    Science.gov (United States)

    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. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  8. The β-Hemolysin and Intracellular Survival of Streptococcus agalactiae in Human Macrophages

    Science.gov (United States)

    Sagar, Anubha; Klemm, Carolin; Hartjes, Lara; Mauerer, Stefanie; van Zandbergen, Ger; Spellerberg, Barbara

    2013-01-01

    S. agalactiae (group B streptococci, GBS) is a major microbial pathogen in human neonates and causes invasive infections in pregnant women and immunocompromised individuals. The S. agalactiae β-hemolysin is regarded as an important virulence factor for the development of invasive disease. To examine the role of β-hemolysin in the interaction with professional phagocytes, the THP-1 monocytic cell line and human granulocytes were infected with a serotype Ia S. agalactiae wild type strain and its isogenic nonhemolytic mutant. We could show that the nonhemolytic mutants were able to survive in significantly higher numbers than the hemolytic wild type strain, in THP-1 macrophage-like cells and in assays with human granulocytes. Intracellular bacterial multiplication, however, could not be observed. The hemolytic wild type strain stimulated a significantly higher release of Tumor Necrosis Factor-α than the nonhemolytic mutant in THP-1 cells, while similar levels of the chemokine Interleukin-8 were induced. In order to investigate bacterial mediators of IL-8 release in this setting, purified cell wall preparations from both strains were tested and found to exert a potent proinflammatory stimulus on THP-1 cells. In conclusion, our results indicate that the β-hemolysin has a strong influence on the intracellular survival of S. agalactiae and that a tightly controlled regulation of β-hemolysin expression is required for the successful establishment of S. agalactiae in different host niches. PMID:23593170

  9. The β-hemolysin and intracellular survival of Streptococcus agalactiae in human macrophages.

    Directory of Open Access Journals (Sweden)

    Anubha Sagar

    Full Text Available S. agalactiae (group B streptococci, GBS is a major microbial pathogen in human neonates and causes invasive infections in pregnant women and immunocompromised individuals. The S. agalactiae β-hemolysin is regarded as an important virulence factor for the development of invasive disease. To examine the role of β-hemolysin in the interaction with professional phagocytes, the THP-1 monocytic cell line and human granulocytes were infected with a serotype Ia S. agalactiae wild type strain and its isogenic nonhemolytic mutant. We could show that the nonhemolytic mutants were able to survive in significantly higher numbers than the hemolytic wild type strain, in THP-1 macrophage-like cells and in assays with human granulocytes. Intracellular bacterial multiplication, however, could not be observed. The hemolytic wild type strain stimulated a significantly higher release of Tumor Necrosis Factor-α than the nonhemolytic mutant in THP-1 cells, while similar levels of the chemokine Interleukin-8 were induced. In order to investigate bacterial mediators of IL-8 release in this setting, purified cell wall preparations from both strains were tested and found to exert a potent proinflammatory stimulus on THP-1 cells. In conclusion, our results indicate that the β-hemolysin has a strong influence on the intracellular survival of S. agalactiae and that a tightly controlled regulation of β-hemolysin expression is required for the successful establishment of S. agalactiae in different host niches.

  10. Transcriptional regulation by Ferric Uptake Regulator (Fur) in pathogenic bacteria.

    Science.gov (United States)

    Troxell, Bryan; Hassan, Hosni M

    2013-01-01

    In the ancient anaerobic environment, ferrous iron (Fe(2+)) was one of the first metal cofactors. Oxygenation of the ancient world challenged bacteria to acquire the insoluble ferric iron (Fe(3+)) and later to defend against reactive oxygen species (ROS) generated by the Fenton chemistry. To acquire Fe(3+), bacteria produce low-molecular weight compounds, known as siderophores, which have extremely high affinity for Fe(3+). However, during infection the host restricts iron from pathogens by producing iron- and siderophore-chelating proteins, by exporting iron from intracellular pathogen-containing compartments, and by limiting absorption of dietary iron. Ferric Uptake Regulator (Fur) is a transcription factor which utilizes Fe(2+) as a corepressor and represses siderophore synthesis in pathogens. Fur, directly or indirectly, controls expression of enzymes that protect against ROS damage. Thus, the challenges of iron homeostasis and defense against ROS are addressed via Fur. Although the role of Fur as a repressor is well-documented, emerging evidence demonstrates that Fur can function as an activator. Fur activation can occur through three distinct mechanisms (1) indirectly via small RNAs, (2) binding at cis regulatory elements that enhance recruitment of the RNA polymerase holoenzyme (RNAP), and (3) functioning as an antirepressor by removing or blocking DNA binding of a repressor of transcription. In addition, Fur homologs control defense against peroxide stress (PerR) and control uptake of other metals such as zinc (Zur) and manganese (Mur) in pathogenic bacteria. Fur family members are important for virulence within bacterial pathogens since mutants of fur, perR, or zur exhibit reduced virulence within numerous animal and plant models of infection. This review focuses on the breadth of Fur regulation in pathogenic bacteria.

  11. Intracellular trafficking of new anticancer therapeutics: antibody–drug conjugates

    Science.gov (United States)

    Kalim, Muhammad; Chen, Jie; Wang, Shenghao; Lin, Caiyao; Ullah, Saif; Liang, Keying; Ding, Qian; Chen, Shuqing; Zhan, Jinbiao

    2017-01-01

    Antibody–drug conjugate (ADC) is a milestone in targeted cancer therapy that comprises of monoclonal antibodies chemically linked to cytotoxic drugs. Internalization of ADC takes place via clathrin-mediated endocytosis, caveolae-mediated endocytosis, and pinocytosis. Conjugation strategies, endocytosis and intracellular trafficking optimization, linkers, and drugs chemistry present a great challenge for researchers to eradicate tumor cells successfully. This inventiveness of endocytosis and intracellular trafficking has given considerable momentum recently to develop specific antibodies and ADCs to treat cancer cells. It is significantly advantageous to emphasize the endocytosis and intracellular trafficking pathways efficiently and to design potent engineered conjugates and biological entities to boost efficient therapies enormously for cancer treatment. Current studies illustrate endocytosis and intracellular trafficking of ADC, protein, and linker strategies in unloading and also concisely evaluate practically applicable ADCs. PMID:28814834

  12. Intracellular trafficking of new anticancer therapeutics: antibody-drug conjugates.

    Science.gov (United States)

    Kalim, Muhammad; Chen, Jie; Wang, Shenghao; Lin, Caiyao; Ullah, Saif; Liang, Keying; Ding, Qian; Chen, Shuqing; Zhan, Jinbiao

    2017-01-01

    Antibody-drug conjugate (ADC) is a milestone in targeted cancer therapy that comprises of monoclonal antibodies chemically linked to cytotoxic drugs. Internalization of ADC takes place via clathrin-mediated endocytosis, caveolae-mediated endocytosis, and pinocytosis. Conjugation strategies, endocytosis and intracellular trafficking optimization, linkers, and drugs chemistry present a great challenge for researchers to eradicate tumor cells successfully. This inventiveness of endocytosis and intracellular trafficking has given considerable momentum recently to develop specific antibodies and ADCs to treat cancer cells. It is significantly advantageous to emphasize the endocytosis and intracellular trafficking pathways efficiently and to design potent engineered conjugates and biological entities to boost efficient therapies enormously for cancer treatment. Current studies illustrate endocytosis and intracellular trafficking of ADC, protein, and linker strategies in unloading and also concisely evaluate practically applicable ADCs.

  13. Data for automated, high-throughput microscopy analysis of intracellular bacterial colonies using spot detection

    DEFF Research Database (Denmark)

    Ernstsen, Christina Lundgaard; Login, Frédéric H.; Jensen, Helene Halkjær

    2017-01-01

    Quantification of intracellular bacterial colonies is useful in strategies directed against bacterial attachment, subsequent cellular invasion and intracellular proliferation. An automated, high-throughput microscopy-method was established to quantify the number and size of intracellular bacteria...

  14. Brucella abortus: pathogenicity and gene regulation of virulence

    Directory of Open Access Journals (Sweden)

    Olga Rivas-Solano

    2015-06-01

    Full Text Available Brucella abortus is a zoonotic intracellular facultative pathogen belonging to the subdivision α2 of class Proteobacteria. It causes a worldwide distributed zoonotic disease called brucellosis. The main symptoms are abortion and sterility in cattle, as well as an undulant febrile condition in humans. In endemic regions like Central America, brucellosis has a high socioeconomic impact. A basic research project was recently conducted at the ITCR with the purpose of studying gene regulation of virulence, structure and immunogenicity in B. abortus. The present review was written as part of this project. B. abortus virulence seems to be determined by its ability to invade, survive and replicate inside professional and non-professional phagocytes. It reaches its intracellular replicative niche without the activation of host antimicrobial mechanisms of innate immunity. It also has gene regulation mechanisms for a rapid adaptation to an intracellular environment such as the two-component signal transduction system BvrR/BvrS and the quorum sensing regulator called Vjbr, as well as other transcription factors. All of them integrate a complex gene regulation network.

  15. Rhodococcus equi: the many facets of a pathogenic actinomycete.

    Science.gov (United States)

    Vázquez-Boland, José A; Giguère, Steeve; Hapeshi, Alexia; MacArthur, Iain; Anastasi, Elisa; Valero-Rello, Ana

    2013-11-29

    Rhodococcus equi is a soil-dwelling pathogenic actinomycete that causes pulmonary and extrapulmonary pyogranulomatous infections in a variety of animal species and people. Young foals are particularly susceptible and develop a life-threatening pneumonic disease that is endemic at many horse-breeding farms worldwide. R. equi is a facultative intracellular parasite of macrophages that replicates within a modified phagocytic vacuole. Its pathogenicity depends on a virulence plasmid that promotes intracellular survival by preventing phagosome-lysosome fusion. Species-specific tropism of R. equi for horses, pigs and cattle appears to be determined by host-adapted virulence plasmid types. Molecular epidemiological studies of these plasmids suggest that human R. equi infection is zoonotic. Analysis of the recently determined R. equi genome sequence has identified additional virulence determinants on the bacterial chromosome. This review summarizes our current understanding of the clinical aspects, biology, pathogenesis and immunity of this fascinating microbe with plasmid-governed infectivity. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Plasma Membrane-Located Purine Nucleotide Transport Proteins Are Key Components for Host Exploitation by Microsporidian Intracellular Parasites

    Science.gov (United States)

    Heinz, Eva; Hacker, Christian; Dean, Paul; Mifsud, John; Goldberg, Alina V.; Williams, Tom A.; Nakjang, Sirintra; Gregory, Alison; Hirt, Robert P.; Lucocq, John M.; Kunji, Edmund R. S.; Embley, T. Martin

    2014-01-01

    Microsporidia are obligate intracellular parasites of most animal groups including humans, but despite their significant economic and medical importance there are major gaps in our understanding of how they exploit infected host cells. We have investigated the evolution, cellular locations and substrate specificities of a family of nucleotide transport (NTT) proteins from Trachipleistophora hominis, a microsporidian isolated from an HIV/AIDS patient. Transport proteins are critical to microsporidian success because they compensate for the dramatic loss of metabolic pathways that is a hallmark of the group. Our data demonstrate that the use of plasma membrane-located nucleotide transport proteins (NTT) is a key strategy adopted by microsporidians to exploit host cells. Acquisition of an ancestral transporter gene at the base of the microsporidian radiation was followed by lineage-specific events of gene duplication, which in the case of T. hominis has generated four paralogous NTT transporters. All four T. hominis NTT proteins are located predominantly to the plasma membrane of replicating intracellular cells where they can mediate transport at the host-parasite interface. In contrast to published data for Encephalitozoon cuniculi, we found no evidence for the location for any of the T. hominis NTT transporters to its minimal mitochondria (mitosomes), consistent with lineage-specific differences in transporter and mitosome evolution. All of the T. hominis NTTs transported radiolabelled purine nucleotides (ATP, ADP, GTP and GDP) when expressed in Escherichia coli, but did not transport radiolabelled pyrimidine nucleotides. Genome analysis suggests that imported purine nucleotides could be used by T. hominis to make all of the critical purine-based building-blocks for DNA and RNA biosynthesis during parasite intracellular replication, as well as providing essential energy for parasite cellular metabolism and protein synthesis. PMID:25474405

  17. Plasma membrane-located purine nucleotide transport proteins are key components for host exploitation by microsporidian intracellular parasites.

    Directory of Open Access Journals (Sweden)

    Eva Heinz

    2014-12-01

    Full Text Available Microsporidia are obligate intracellular parasites of most animal groups including humans, but despite their significant economic and medical importance there are major gaps in our understanding of how they exploit infected host cells. We have investigated the evolution, cellular locations and substrate specificities of a family of nucleotide transport (NTT proteins from Trachipleistophora hominis, a microsporidian isolated from an HIV/AIDS patient. Transport proteins are critical to microsporidian success because they compensate for the dramatic loss of metabolic pathways that is a hallmark of the group. Our data demonstrate that the use of plasma membrane-located nucleotide transport proteins (NTT is a key strategy adopted by microsporidians to exploit host cells. Acquisition of an ancestral transporter gene at the base of the microsporidian radiation was followed by lineage-specific events of gene duplication, which in the case of T. hominis has generated four paralogous NTT transporters. All four T. hominis NTT proteins are located predominantly to the plasma membrane of replicating intracellular cells where they can mediate transport at the host-parasite interface. In contrast to published data for Encephalitozoon cuniculi, we found no evidence for the location for any of the T. hominis NTT transporters to its minimal mitochondria (mitosomes, consistent with lineage-specific differences in transporter and mitosome evolution. All of the T. hominis NTTs transported radiolabelled purine nucleotides (ATP, ADP, GTP and GDP when expressed in Escherichia coli, but did not transport radiolabelled pyrimidine nucleotides. Genome analysis suggests that imported purine nucleotides could be used by T. hominis to make all of the critical purine-based building-blocks for DNA and RNA biosynthesis during parasite intracellular replication, as well as providing essential energy for parasite cellular metabolism and protein synthesis.

  18. Pathogenic mycoflora on carrot seeds

    Directory of Open Access Journals (Sweden)

    Bogdan Nowicki

    2013-12-01

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

  19. Arcobacter halophilus sp nov., the first obligate halophile in the genus Arcobacter

    DEFF Research Database (Denmark)

    Donachie, S.P.; Bowman, J.P.; On, Stephen L.W.

    2005-01-01

    . Most notably, LA31B(T) was found to be an obligate halophile, a hitherto undescribed feature among recognized Arcobacter species. These data indicate that LA31B(T) should be considered to represent a novel species in the genus Arcobacter, for which the name Arcobacter halophilus sp. nov. is proposed....... This is the first obligately halophilic member of the genus. The type strain is LA31B(T) (= ATCC BAA- 102 2 T=CIP 108450(T))....

  20. Post-trial obligations in the Declaration of Helsinki 2013: classification, reconstruction and interpretation.

    Science.gov (United States)

    Mastroleo, Ignacio

    2016-08-01

    The general aim of this article is to give a critical interpretation of post-trial obligations towards individual research participants in the Declaration of Helsinki 2013. Transitioning research participants to the appropriate health care when a research study ends is a global problem. The publication of a new version of the Declaration of Helsinki is a great opportunity to discuss it. In my view, the Declaration of Helsinki 2013 identifies at least two clearly different types of post-trial obligations, specifically, access to care after research and access to information after research. The agents entitled to receive post-trial access are the individual participants in research studies. The Declaration identifies the sponsors, researchers and host country governments as the main agents responsible for complying with the post-trial obligations mentioned above. To justify this interpretation of post-trial obligations, I first introduce a classification of post-trial obligations and illustrate its application with examples from post-trial ethics literature. I then make a brief reconstruction of the formulations of post-trial obligations of the Declaration of Helsinki from 2000 to 2008 to correlate the changes with some of the most salient ethical arguments. Finally I advance a critical interpretation of the latest formulation of post-trial obligations. I defend the view that paragraph 34 of 'Post-trial provisions' is an improved formulation by comparison with earlier versions, especially for identifying responsible agents and abandoning ambiguous 'fair benefit' language. However, I criticize the disappearance of 'access to other appropriate care' present in the Declaration since 2004 and the narrow scope given to obligations of access to information after research. © 2015 John Wiley & Sons Ltd.