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1

Genome degeneration affects both extracellular and intracellular bacterial endosymbionts  

PubMed Central

The obligate intracellular bacterial endosymbionts of insects are a paradigm for reductive genome evolution. A study published recently in BMC Biology demonstrates that similar evolutionary forces shaping genome structure may also apply to extracellular endosymbionts. PMID:19435469

Feldhaar, Heike; Gross, Roy

2009-01-01

2

Molecular pathogenesis of the obligate intracellular bacterium Coxiella burnetii  

PubMed Central

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

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

2014-01-01

3

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

PubMed Central

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

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

2010-01-01

4

Rickettsia Phylogenomics: Unwinding the Intricacies of Obligate Intracellular Life  

PubMed Central

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

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

2008-01-01

5

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

E-print Network

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

Bordenstein, Seth

6

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

Microsoft Academic Search

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)

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

2008-01-01

7

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

PubMed Central

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

2013-01-01

8

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

PubMed Central

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

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

2012-01-01

9

Bacterial Pathogens Commandeer Rab GTPases to Establish Intracellular Niches  

PubMed Central

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

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

2012-01-01

10

Exploring Anti-Bacterial Compounds against Intracellular Legionella  

PubMed Central

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 ?-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

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

11

Exploring anti-bacterial compounds against intracellular Legionella.  

PubMed

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 ?-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

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

12

Autophagic clearance of bacterial pathogens: molecular recognition of intracellular microorganisms  

PubMed Central

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

Mansilla Pareja, Maria Eugenia; Colombo, Maria I.

2013-01-01

13

Innovative approach for transcriptomic analysis of obligate intracellular pathogen: selective capture of transcribed sequences of Ehrlichia ruminantium  

Microsoft Academic Search

BACKGROUND: Whole genome transcriptomic analysis is a powerful approach to elucidate the molecular mechanisms controlling the pathogenesis of obligate intracellular bacteria. However, the major hurdle resides in the low quantity of prokaryotic mRNAs extracted from host cells. Our model Ehrlichia ruminantium (ER), the causative agent of heartwater, is transmitted by tick Amblyomma variegatum. This bacterium affects wild and domestic ruminants

Loïc Emboulé; France Daigle; Damien F Meyer; Bernard Mari; Valérie Pinarello; Christian Sheikboudou; Virginie Magnone; Roger Frutos; Alain Viari; Pascal Barbry; Dominique Martinez; Thierry Lefrançois; Nathalie Vachiéry

2009-01-01

14

Current Biology 16, 16461651, August 22, 2006 2006 Elsevier Ltd All rights reserved DOI 10.1016/j.cub.2006.06.060 The Obligate Intracellular Pathogen  

E-print Network

, and signaling [1]. We report that infection with the obligate intracellular pathogen Chlamydia trachomatis.cub.2006.06.060 Report The Obligate Intracellular Pathogen Chlamydia trachomatis Targets Host Lipid of neutral-lipid-rich struc- tures with features of LDs at the cytoplasmic surface of the bacteria

Valdivia, Raphael

15

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

PubMed Central

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

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

2012-01-01

16

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

SciTech Connect

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).

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

17

Analysis of Fluorescent Protein Expression in Transformants of Rickettsia monacensis, an Obligate Intracellular Tick Symbiont  

PubMed Central

We developed and applied transposon-based transformation vectors for molecular manipulation and analysis of spotted fever group rickettsiae, which are obligate intracellular bacteria that infect ticks and, in some cases, mammals. Using the Epicentre EZ::TN transposon system, we designed transposons for simultaneous expression of a reporter gene and a chloramphenicol acetyltransferase (CAT) resistance marker. Transposomes (transposon-transposase complexes) were electroporated into Rickettsia monacensis, a rickettsial symbiont isolated from the tick Ixodes ricinus. Each transposon contained an expression cassette consisting of the rickettsial ompA promoter and a green fluorescent protein (GFP) reporter gene (GFPuv) or the ompB promoter and a red fluorescent protein reporter gene (DsRed2), followed by the ompA transcription terminator and a second ompA promoter CAT gene cassette. Selection with chloramphenicol gave rise to rickettsial populations with chromosomally integrated single-copy transposons as determined by PCR, Southern blotting, and sequence analysis. Reverse transcription-PCR and Northern blots demonstrated transcription of all three genes. GFPuv transformant rickettsiae exhibited strong fluorescence in individual cells, but DsRed2 transformants did not. Western blots confirmed expression of GFPuv in R. monacensis and in Escherichia coli, but DsRed2 was expressed only in E. coli. The DsRed2 gene, but not the GFPuv gene, contains many GC-rich amino acid codons that are rare in the preferred codon suite of rickettsiae, possibly explaining the failure to express DsRed2 protein in R. monacensis. We demonstrated that our vectors provide a means to study rickettsia-host cell interactions by visualizing GFPuv-fluorescent R. monacensis associated with actin tails in tick host cells. PMID:15812043

Baldridge, Gerald D.; Burkhardt, Nicole; Herron, Michael J.; Kurtti, Timothy J.; Munderloh, Ulrike G.

2005-01-01

18

A MyD88-Dependent Early IL-17 Production Protects Mice against Airway Infection with the Obligate Intracellular Pathogen Chlamydia muridarum1  

PubMed Central

We found that IL-17, a signature cytokine of Th17, was produced early in the innate immunity phase after an intranasal infection with the obligate intracellular pathogen Chlamydia muridarum. The airway IL-17, which peaked at 48 h after infection, was dependent on live chlamydial organism replication and MyD88-mediated signaling pathways. Treatment with antibiotics or knockout of the MyD88 gene, but not Toll/IL receptor domain-containing adapter-inducing IFN-?, can block the early IL-17 production. Treatment of mice with an anti-IL-17-neutralizing mAb enhanced growth of chlamydial organisms in the lung, dissemination to other organs, and decreased mouse survival, whereas treatment with an isotype-matched control IgG had no effect. Although IL-17 did not directly affect chlamydial growth in cell culture, it enhanced the production of other inflammatory cytokines and chemokines by Chlamydia-infected cells and promoted neutrophil infiltration in mouse airways during chlamydial infection, which may contribute to the antichlamydial effect of IL-17. These observations suggest that an early IL-17 response as an innate immunity component plays an important role in initiating host defense against infection with intracellular bacterial pathogens in the airway. PMID:19542374

Zhang, Xiaoyun; Gao, Lifen; Lei, Lei; Zhong, Youmin; Dube, Peter; Berton, Michael T.; Arulanandam, Bernard; Zhang, Jinshun; Zhong, Guangming

2009-01-01

19

Metabolic host responses to infection by intracellular bacterial pathogens  

PubMed Central

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

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

2013-01-01

20

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

PubMed Central

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. PMID:16549792

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

2006-01-01

21

Infection of zebrafish embryos with intracellular bacterial pathogens.  

PubMed

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

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

2012-01-01

22

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

PubMed Central

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

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

2014-01-01

23

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

PubMed

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

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

2014-06-01

24

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

PubMed

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

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

2015-02-01

25

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

PubMed Central

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

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

2011-01-01

26

Infected Dendritic Cells Facilitate Systemic Dissemination and Transplacental Passage of the Obligate Intracellular Parasite Neospora caninum in Mice  

PubMed Central

The obligate intracellular parasite Neospora caninum disseminates across the placenta and the blood-brain barrier, to reach sites where it causes severe pathology or establishes chronic persistent infections. The mechanisms used by N. caninum to breach restrictive biological barriers remain elusive. To examine the cellular basis of these processes, migration of different N. caninum isolates (Nc-1, Nc-Liverpool, Nc-SweB1 and the Spanish isolates: Nc-Spain 3H, Nc-Spain 4H, Nc-Spain 6, Nc-Spain 7 and Nc-Spain 9) was studied in an in vitro model based on a placental trophoblast-derived BeWo cell line. Here, we describe that infection of dendritic cells (DC) by N. caninum tachyzoites potentiated translocation of parasites across polarized cellular monolayers. In addition, powered by the parasite's own gliding motility, extracellular N. caninum tachyzoites were able to transmigrate across cellular monolayers. Altogether, the presented data provides evidence of two putative complementary pathways utilized by N. caninum, in an isolate-specific fashion, for passage of restrictive cellular barriers. Interestingly, adoptive transfer of tachyzoite-infected DC in mice resulted in increased parasitic loads in various organs, e.g. the central nervous system, compared to infections with free parasites. Inoculation of pregnant mice with infected DC resulted in an accentuated vertical transmission to the offspring with increased parasitic loads and neonatal mortality. These findings reveal that N. caninum exploits the natural cell trafficking pathways in the host to cross cellular barriers and disseminate to deep tissues. The findings are indicative of conserved dissemination strategies among coccidian apicomplexan parasites. PMID:22403627

Collantes-Fernandez, Esther; Arrighi, Romanico B. G.; Álvarez-García, Gema; Weidner, Jessica M.; Regidor-Cerrillo, Javier; Boothroyd, John C.; Ortega-Mora, Luis M.; Barragan, Antonio

2012-01-01

27

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

PubMed Central

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

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

2014-01-01

28

Genomic signatures of obligate host dependence in the luminous bacterial symbiont of a vertebrate.  

PubMed

The majority of bacteria engaged in bioluminescent symbiosis are environmentally acquired and facultatively symbiotic. A few enigmatic bioluminescent symbionts have not been successfully cultured, which has led to speculation that they may be obligately dependent on their hosts. Here, we report the draft genome of the uncultured luminous symbiont of an anomalopid flashlight fish, 'Candidatus?Photodesmus katoptron'. The genome of the anomalopid symbiont is reduced by 80% compared with close relatives and lacks almost all genes necessary for amino acid synthesis and for metabolism of energy sources other than glucose, supporting obligate dependence on the host for growth. 'Candidatus?Photodesmus katoptron' is the first described obligate mutualistic symbiont of a vertebrate. Unlike most other obligate mutualists, the anomalopid symbiont genome has retained complete pathways for chemotaxis and motility as well as most genes involved in cell wall production, consistent with the hypothesis that these bacteria may be transmitted environmentally during an extra-host phase. PMID:24118864

Hendry, Tory A; de Wet, Jeffrey R; Dunlap, Paul V

2014-08-01

29

A bacterial-two-hybrid selection system for one-step isolation of intracellularly functional Nanobodies.  

PubMed

Camel single-domain antibody fragments or Nanobodies, are practical in a wide range of applications. Their unique biochemical and biophysical properties permit an intracellular expression and antigen targeting. The availability of an efficient intracellular selection step would immediately identify the best intracellularly performing functional antibody fragments. Therefore, we assessed a bacterial-two-hybrid system to retrieve such Nanobodies. With GFP as an antigen we demonstrate that antigen-specific Nanobodies of sub-micromolar affinity and stability above 30 kJ/mol, at a titer of 10(-4) can be retrieved in a single-step selection. This was further proven practically by the successful recovery from an 'immune' library of multiple stable, antigen-specific Nanobodies of good affinity for HIV-1 integrase or nucleoside hydrolase. The sequence diversity, intrinsic domain stability, antigen-specificity and affinity of these binders compare favorably to those that were retrieved in parallel by phage display pannings. PMID:22583807

Pellis, Mireille; Pardon, Els; Zolghadr, Kourosh; Rothbauer, Ulrich; Vincke, Cécile; Kinne, Joerg; Dierynck, Inge; Hertogs, Kurt; Leonhardt, Heinrich; Messens, Joris; Muyldermans, Serge; Conrath, Katja

2012-10-15

30

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

PubMed Central

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

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

31

ORIGINAL ARTICLE Detection of a novel intracellular microbiome hosted  

E-print Network

ORIGINAL ARTICLE Detection of a novel intracellular microbiome hosted in arbuscular mycorrhizal) are important members of the plant microbiome. They are obligate biotrophs that colonize the roots of most land time that fungi support an intracellular bacterial microbiome, in which distinct types of endobacteria

Bruns, Tom

32

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

PubMed

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

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

2014-08-01

33

Multi-species bacterial biofilm and intracellular infection in otitis media  

PubMed Central

Background Bacteria which are metabolically active yet unable to be cultured and eradicated by antibiotic treatment are present in the middle ear effusion of children with chronic otitis media with effusion (COME) and recurrent acute otitis media (rAOM). These observations are suggestive of biofilm presence or intracellular sequestration of bacteria and may play a role in OM pathogenesis. The aim of this project is to provide evidence for the presence of otopathogenic bacteria intracellularly or within biofilm in the middle ear mucosa of children with COME or rAOM. Methods Middle ear mucosal biopsies from 20 children with COME or rAOM were examined for otopathogenic bacteria (either in biofilm or located intracellularly) using transmission electron microscopy (TEM) or species specific fluorescent in situ hybridisation (FISH) and confocal laser scanning microscopy (CLSM). One healthy control biopsy from a child undergoing cochlear implant surgery was also examined. Results No bacteria were observed in the healthy control sample. In 2 of the 3 biopsies imaged using TEM, bacteria were observed in mucus containing vacuoles within epithelial cells. Bacterial species within these could not be identified and biofilm was not observed. Using FISH with CLSM, bacteria were seen in 15 of the 17 otitis media mucosal specimens. In this group, 11 (65%) of the 17 middle ear mucosal biopsies showed evidence of bacterial biofilm and 12 demonstrated intracellular bacteria. 52% of biopsies were positive for both biofilm and intracellular bacteria. At least one otopathogen was identified in 13 of the 15 samples where bacteria were present. No differences were observed between biopsies from children with COME and those with rAOM. Conclusion Using FISH and CLSM, bacterial biofilm and intracellular infection with known otopathogens are demonstrated on/in the middle ear mucosa of children with COME and/or rAOM. While their role in disease pathogenesis remains to be determined, this previously undescribed infection pattern may help explain the ineffectiveness of current treatment strategies at preventing or resolving COME or rAOM. PMID:22018357

2011-01-01

34

The "domino theory" of gene death: gradual and mass gene extinction events in three lineages of obligate symbiotic bacterial pathogens.  

PubMed

During the adaptation of an organism to a parasitic lifestyle, various gene functions may be rendered superfluous due to the fact that the host may supply these needs. As a consequence, obligate symbiotic bacterial pathogens tend to undergo reductive genomic evolution through gene death (nonfunctionalization or pseudogenization) and deletion. Here, we examine the evolutionary sequence of gene-death events during the process of genome miniaturization in three bacterial species that have experienced extensive genome reduction: Mycobacterium leprae, Shigella flexneri, and Salmonella typhi. We infer that in all three lineages, the distribution of functional categories is similar in pseudogenes and genes but different from that of absent genes. Based on an analysis of evolutionary distances, we propose a two-step "domino effect" model for reductive genome evolution. The process starts with a gradual gene-by-gene-death sequence of events. Eventually, a crucial gene within a complex pathway or network is rendered nonfunctional triggering a "mass gene extinction" of the dependent genes. In contrast to published reports according to which genes belonging to certain functional categories are prone to nonfunctionalization more frequently and earlier than genes belonging to other functional categories, we could discern no characteristic regularity in the temporal order of function loss. PMID:16237210

Dagan, Tal; Blekhman, Ran; Graur, Dan

2006-02-01

35

RIG-I Detects mRNA of Intracellular Salmonella enterica Serovar Typhimurium during Bacterial Infection  

PubMed Central

ABSTRACT The cytoplasmic helicase RIG-I is an established sensor for viral 5?-triphosphorylated RNA species. Recently, RIG-I was also implicated in the detection of intracellular bacteria. However, little is known about the host cell specificity of this process and the bacterial pathogen-associated molecular pattern (PAMP) that activates RIG-I. Here we show that RNA of Salmonella enterica serovar Typhimurium activates production of beta interferon in a RIG-I-dependent fashion only in nonphagocytic cells. In phagocytic cells, RIG-I is obsolete for detection of Salmonella infection. We further demonstrate that Salmonella mRNA reaches the cytoplasm during infection and is thus accessible for RIG-I. The results from next-generation sequencing analysis of RIG-I-associated RNA suggest that coding bacterial mRNAs represent the activating PAMP. PMID:24692634

Schmolke, Mirco; Patel, Jenish R.; de Castro, Elisa; Sánchez-Aparicio, Maria T.; Uccellini, Melissa B.; Miller, Jennifer C.; Manicassamy, Balaji; Satoh, Takashi; Kawai, Taro; Akira, Shizuo; Merad, Miriam; García-Sastre, Adolfo

2014-01-01

36

Nods, Nalps and Naip: intracellular regulators of bacterial-induced inflammation.  

PubMed

The innate immune system is the most ancestral and ubiquitous system of defence against microbial infection. The microbial sensing proteins involved in innate immunity recognize conserved and often structural components of microorganisms. One class of these pattern-recognition molecules, the Toll-like receptors (TLRs), are involved in detection of microbes in the extracellular compartment whereas a newly discovered family of proteins, the NBS-LRR proteins (for nucleotide-binding site and leucine-rich repeat), are involved in intracellular recognition of microbes and their products. NBS-LRR proteins are characterized by three structural domains: a C-terminal leucine-rich repeat (LRR) domain able to sense a microbial motif, an intermediary nucleotide binding site (NBS) essential for the oligomerization of the molecule that is necessary for the signal transduction induced by different N-terminal effector motifs, such as a pyrin domain (PYD), a caspase-activating and recruitment domain (CARD) or a baculovirus inhibitor of apoptosis protein repeat (BIR) domain. Two of these family members, Nod1 and Nod2, play a role in the regulation of pro-inflammatory pathways through NF-kappaB induced by bacterial ligands. Recently, it was shown that Nod2 recognizes a specific peptidoglycan motif from bacteria, muramyl dipeptide (MDP). A surprising number of human genetic disorders have been linked to NBS-LRR proteins. For example, mutations in Nod2, which render the molecule insensitive to MDP and unable to induce NF-kappaB activation when stimulated, are associated with susceptibility to a chronic intestinal inflammatory disorder, Crohn's disease. Conversely, mutations in the NBS region of Nod2 induce a constitutive activation of NF-kappaB and are responsible for Blau syndrome, another auto-inflammatory disease. Nalp3, which is an NBS-LRR protein with an N-terminal Pyrin domain, is also implicated in rare auto-inflammatory disorders. In conclusion, NBS-LRR molecules appear as a new family of intracellular receptors of innate immunity able to detect specific bacterial compounds and induce inflammatory response; the dysregulation of these processes due to mutations in the genes encoding these proteins is involved in numerous auto-inflammatory disorders. PMID:12925128

Chamaillard, Mathias; Girardin, Stephen E; Viala, Jérôme; Philpott, Dana J

2003-09-01

37

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

PubMed Central

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

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

2014-01-01

38

Genome sequence of Blochmannia pennsylvanicus indicates parallel evolutionary trends among bacterial mutualists of insects  

Microsoft Academic Search

The distinct lifestyle of obligately intracellular bacteria can alter fundamental forces that drive and constrain genome change. In this study, sequencing the 792-kb genome of Blochmannia pennsylvanicus, an obligate endosymbiont of Camponotus pennsylvanicus, enabled us to trace evolutionary changes that occurred in the context of a bacterial-ant association. Comparison to the genome of Blochmannia floridanus reveals differential loss of genes

Patrick H. Degnan; Adam B. Lazarus; Jennifer J. Wernegreen

2005-01-01

39

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

Microsoft Academic Search

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

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

2011-01-01

40

A Rickettsia genome overrun by mobile genetic elements provides insight into the acquisition of genes characteristic of an obligate intracellular lifestyle.  

PubMed

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

Gillespie, Joseph J; 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

41

Label-free imaging and spectroscopic analysis of intracellular bacterial infections.  

PubMed

Staphylococcus aureus is one of the most frequent human pathogens that can also act as a facultative intracellular pathogen causing infections that are extremely difficult to treat. Only little is known about the pathogen's intracellular adaptation strategies to escape the host's response. Here, we present an advanced Raman-based imaging approach providing high quality false-color images to specifically identify intracellular S. aureus and to localize them exactly in three dimensions within endothelial cells. At the same time unprecedented insights into the metabolic characteristics of the pathogen are provided in a label-free and nondestructive manner. The spectral information reveals that the intracellular bacteria are in the exponential growth phase with a reduced replication rate and biochemically different from extracellular bacteria proving their adaptation to the host's conditions. This powerful biophotonic analysis tool paves the way for further mechanistic studies of difficult-to-investigate infection processes. PMID:25582952

Große, Christina; Bergner, Norbert; Dellith, Jan; Heller, Regine; Bauer, Michael; Mellmann, Alexander; Popp, Jürgen; Neugebauer, Ute

2015-02-17

42

Polysaccharide Capsule and Sialic Acid-Mediated Regulation Promote Biofilm-Like Intracellular Bacterial Communities during Cystitis ?  

PubMed Central

Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs). A murine UTI model has revealed an infection cascade whereby UPEC undergoes cycles of invasion of the bladder epithelium, intracellular proliferation in polysaccharide-containing biofilm-like masses called intracellular bacterial communities (IBC), and then dispersal into the bladder lumen to initiate further rounds of epithelial colonization and invasion. We predicted that the UPEC K1 polysaccharide capsule is a key constituent of the IBC matrix. Compared to prototypic E. coli K1 strain UTI89, a capsule assembly mutant had a fitness defect in functionally TLR4+ and TLR4? mice, suggesting a protective role of capsule in inflamed and noninflamed hosts. K1 capsule assembly and synthesis mutants had dramatically reduced IBC formation, demonstrating the common requirement for K1 polysaccharide in IBC development. The capsule assembly mutant appeared dispersed in the cytoplasm of the bladder epithelial cells and failed to undergo high-density intracellular replication during later stages of infection, when the wild-type strain continued to form serial generations of IBC. Deletion of the sialic acid regulator gene nanR partially restored IBC formation in the capsule assembly mutant. These data suggest that capsule is necessary for efficient IBC formation and that aberrant sialic acid accumulation, resulting from disruption of K1 capsule assembly, produces a NanR-mediated defect in intracellular proliferation and IBC development. Together, these data demonstrate the complex but important roles of UPEC polysaccharide encapsulation and sialic acid signaling in multiple stages of UTI pathogenesis. PMID:20086090

Anderson, Gregory G.; Goller, Carlos C.; Justice, Sheryl; Hultgren, Scott J.; Seed, Patrick C.

2010-01-01

43

Mechanism of tachyplesin I injury to bacterial membranes and intracellular enzymes, determined by laser confocal scanning microscopy and flow cytometry.  

PubMed

Tachyplesin I is a 17 amino acid, cationic, antimicrobial peptide with a typical cyclic antiparallel ?-sheet structure. Interactions of tachyplesin I with living bacteria are not well understood, although models have been used to elucidate how tachyplesin I permeabilizes membranes. There are several questions to be answered, such as (i) how does tachyplesin I kill bacteria after it penetrates the membrane and (ii) does bacterial death result from the inactivation of intracellular esterases as well as cell injury? In this study, the dynamic antibacterial processes of tachyplesin I and its interactions with Escherichia coli and Staphylococcus aureus were investigated using laser confocal scanning microscopy in combination with electron microscopy. The effects of tachyplesin I on E. coli cell membrane integrity, intracellular enzyme activity, and cell injury and death were investigated by flow cytometric analysis of cells following single- or double-staining with carboxyfluorescein diacetate or propidium iodide. The results of microscopy indicated that tachyplesin I kills bacteria by acting on the cell membrane and intracellular contents, with the cell membrane representing the primary target. Microscopy results also revealed that tachyplesin I uses different modes of action against E. coli and S. aureus. The results of flow cytometry showed that tachyplesin I caused E. coli cell death mainly by compromising cell membrane integrity and causing the inactivation of intracellular esterases. Flow cytometry also revealed dynamic changes in the different subpopulations of cells with increase in tachyplesin I concentrations. Bacteria exposed to 5?g/mL of tachyplesin I did not die instantaneously; instead, they died gradually via a sublethal injury. However, upon exposure to 10-40?g/mL of tachyplesin I, the bacteria died almost immediately. These results contribute to our understanding of the antibacterial mechanism employed by tachyplesin I. PMID:25267486

Hong, Jun; Guan, Wutai; Jin, Gang; Zhao, Hongya; Jiang, Xiaohua; Dai, Jianguo

2015-01-01

44

Bacterial Community Morphogenesis Is Intimately Linked to the Intracellular Redox State  

PubMed Central

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

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

2013-01-01

45

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

Microsoft Academic Search

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

John M. Dow; Yvonne Fouhy

46

Escherichia coli from urine of female patients with urinary tract infections is competent for intracellular bacterial community formation.  

PubMed

Nearly 50% of women experience at least one urinary tract infection (UTI) in their lifetime. Studies with mice have revealed that uropathogenic Escherichia coli (UPEC) isolates invade superficial umbrella cells that line the bladder, allowing them to find a safe haven and subvert clearance by innate host responses. Rapid intracellular replication results in the formation of distinctive intracellular bacterial communities (IBCs). In this study, we evaluated whether UPEC strains cultured from the urine of women and classified as causing acute cystitis, recurrent cystitis, asymptomatic bacteriuria, or pyelonephritis could progress through the IBC cascade in a well-characterized mouse model of cystitis. Of 18 UPEC isolates collected from women, 15 formed IBCs. Variations in the size, number, and kinetics of IBC formation were observed with strains isolated from women with different clinical syndromes. Two of the three isolates that did not form IBCs when inoculated alone were able to do so when coinoculated with an isolate that was capable of generating IBCs. The mixed infections dramatically altered the behavior of the coinfecting bacteria relative to their behavior in a single infection. The study also showed that mice with five different genetic backgrounds can support IBC formation. Although UPEC isolates differ genetically in their virulence factors, the majority of UPEC isolates from different types of UTI proceed through the IBC pathway, confirming the generality of IBCs in UTI pathogenesis in mice. PMID:17074856

Garofalo, Corinne K; Hooton, Thomas M; Martin, Steven M; Stamm, Walter E; Palermo, Joseph J; Gordon, Jeffrey I; Hultgren, Scott J

2007-01-01

47

Escherichia coli from Urine of Female Patients with Urinary Tract Infections Is Competent for Intracellular Bacterial Community Formation?  

PubMed Central

Nearly 50% of women experience at least one urinary tract infection (UTI) in their lifetime. Studies with mice have revealed that uropathogenic Escherichia coli (UPEC) isolates invade superficial umbrella cells that line the bladder, allowing them to find a safe haven and subvert clearance by innate host responses. Rapid intracellular replication results in the formation of distinctive intracellular bacterial communities (IBCs). In this study, we evaluated whether UPEC strains cultured from the urine of women and classified as causing acute cystitis, recurrent cystitis, asymptomatic bacteriuria, or pyelonephritis could progress through the IBC cascade in a well-characterized mouse model of cystitis. Of 18 UPEC isolates collected from women, 15 formed IBCs. Variations in the size, number, and kinetics of IBC formation were observed with strains isolated from women with different clinical syndromes. Two of the three isolates that did not form IBCs when inoculated alone were able to do so when coinoculated with an isolate that was capable of generating IBCs. The mixed infections dramatically altered the behavior of the coinfecting bacteria relative to their behavior in a single infection. The study also showed that mice with five different genetic backgrounds can support IBC formation. Although UPEC isolates differ genetically in their virulence factors, the majority of UPEC isolates from different types of UTI proceed through the IBC pathway, confirming the generality of IBCs in UTI pathogenesis in mice. PMID:17074856

Garofalo, Corinne K.; Hooton, Thomas M.; Martin, Steven M.; Stamm, Walter E.; Palermo, Joseph J.; Gordon, Jeffrey I.; Hultgren, Scott J.

2007-01-01

48

Differential effects of type I and II interferons on myeloid cells and resistance to intracellular bacterial infections  

PubMed Central

The type I and II interferons (IFNs) play important roles in regulating immune responses during viral and bacterial infections and in the context of autoimmune and neoplastic diseases. These two IFN types bind to distinct cell surface receptors that are expressed by nearly all cells to trigger signal transduction events and elicit diverse cellular responses. In some cases, type I and II IFNs trigger similar cellular responses while in other cases the IFNs have unique or antagonistic effects on host cells. Negative regulators of IFN signaling also modulate cellular responses to the IFNs and play important roles in maintaining immunological homeostasis. In this review article, we provide an overview of how IFNs stimulate cellular responses. We discuss the disparate effects of type I and II IFNs on host resistance to certain intracellular bacterial infections and provide an overview of models that have been proposed to account for these disparate effects. Mechanisms of antagonistic cross talk between type I and II IFNs are also introduced. PMID:22983898

Kearney, Staci; Delgado, Christine; Lenz, Laurel L.

2014-01-01

49

The Role of Non-Cognate T Cell Stimulation during Intracellular Bacterial Infection  

PubMed Central

Intra-macrophage bacterial infections cause significant morbidity and mortality in both the developed and developing world. Protective host immune responses to these infections initially requires the activation and expansion of pathogen-specific CD4 Th1 cells within lymphoid tissues and subsequent relocation of these effector cells to sites of infection. After entering infected tissues, the elicitation of Th1 bactericidal activity can be triggered by cognate or non-cognate signals that are delivered by locally infected antigen-presenting cells and innate cells. However, the contribution of non-cognate stimulation to the resolution of bacterial infection remains poorly understood, especially in the context of a Th1 response. Here, we review the current data on Th1 cell activation and expansion in mouse models of Salmonella and Chlamydia infection and discuss the potential role of non-cognate Th1 cell stimulation in these disease models. Greater understanding of this pathway of T cell activation may lead to the design of therapeutics or vaccines to combat intra-macrophage pathogens. PMID:25071779

McSorley, Stephen J.

2014-01-01

50

Invasion of the Central Nervous System by Intracellular Bacteria  

PubMed Central

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

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

2004-01-01

51

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

PubMed Central

The existence of a symbiotic relationship between Trichomonas vaginalis and Mycoplasma hominis, which is the first reported example of symbiosis between two obligate human pathogens, has been recently reported by our research group. In this work, we examined the cellular location of M. hominis in respect to T. vaginalis. By using gentamicin protection assays, double immunofluorescence, and confocal microscopy, we obtained strong evidence that M. hominis is located within protozoan cells. 5-Bromodeoxyuridine incorporation assays showed that intracellularly located mycoplasmas actively synthesize DNA. Our results demonstrate that M. hominis has the capability of entering trichomonad cells and of replicating inside the protozoon. These findings suggest that symbiosis might provide the bacteria, during human infection, with the capability to resist to environmental stresses, such as host defense mechanisms and pharmacological therapies. PMID:15664961

Dessì, Daniele; Delogu, Giuseppe; Emonte, Eleonora; Catania, Maria Rosaria; Fiori, Pier Luigi; Rappelli, Paola

2005-01-01

52

Mechanism of Asp24 Upregulation in Brucella abortus Rough Mutant with a Disrupted O-Antigen Export System and Effect of Asp24 in Bacterial Intracellular Survival  

PubMed Central

We previously showed that Brucella abortus rough mutant strain 2308 ?ATP (called the ?rfbE mutant in this study) exhibits reduced intracellular survival in RAW264.7 cells and attenuated persistence in BALB/c mice. In this study, we performed microarray analysis to detect genes with differential expression between the ?rfbE mutant and wild-type strain S2308. Interestingly, acid shock protein 24 gene (asp24) expression was significantly upregulated in the ?rfbE mutant compared to S2308, as confirmed by quantitative reverse transcription-PCR (qRT-PCR) and Western blotting. Further studies using additional strains indicated that the upregulation of asp24 occurred only in rough mutants with disrupted O-antigen export system components, including the ATP-binding protein gene rfbE (bab1_0542) and the permease gene rfbD (bab1_0543), while the ?wboA rough mutant (which lacks an O-antigen synthesis-related glycosyltransferase) and the RB51 strain (a vaccine strain with the rough phenotype) showed no significant changes in asp24 expression compared to S2308. In addition, abolishing the intracellular O-antigen synthesis of the ?rfbE mutant by deleting the wboA gene (thereby creating the ?rfbE ?wboA double-knockout strain) recovered asp24 expression. These results indicated that asp24 upregulation is associated with intracellular O-antigen synthesis and accumulation but not with the bacterial rough phenotype. Further studies indicated that asp24 upregulation in the ?rfbE mutant was associated neither with bacterial adherence and invasion nor with cellular necrosis on RAW264.7 macrophages. However, proper expression of the asp24 gene favors intracellular survival of Brucella in RAW264.7 cells and HeLa cells during an infection. This study reveals a novel mechanism for asp24 upregulation in B. abortus mutants. PMID:24752516

Tian, Mingxing; Qu, Jing; Han, Xiangan; Ding, Chan; Wang, Shaohui; Peng, Daxin

2014-01-01

53

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

Microsoft Academic Search

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

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

2007-01-01

54

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

E-print Network

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

Bell, John Alexander

2014-06-28

55

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

Microsoft Academic Search

BACKGROUND: Analysis of complete microbial genomes showed that intracellular parasites and other microorganisms that inhabit stable ecological niches encode relatively primitive signaling systems, whereas environmental microorganisms typically have sophisticated systems of environmental sensing and signal transduction. RESULTS: This paper presents results of a comprehensive census of signal transduction proteins--histidine kinases, methyl-accepting chemotaxis receptors, Ser\\/Thr\\/Tyr protein kinases, adenylate and diguanylate cyclases

M. Y. Galperin

2005-01-01

56

Role of CheW Protein in Coupling Membrane Receptors to the Intracellular Signaling System of Bacterial Chemotaxis  

NASA Astrophysics Data System (ADS)

Chemotactic behavior in Escherichia coli is mediated by membrane-associated chemoreceptors that transmit sensory signals to the flagellar motors through an intracellular signaling system, which appears to involve a protein phosphorylation cascade. This study concerns the role of CheW, a cytoplasmic protein, in coupling methyl-accepting chemotaxis proteins (MCPs), the major class of membrane receptors, to the intracellular signaling system. Steady-state flagellar rotation behavior was examined in a series of strains with different combinations and relative amounts of CheW, MCPs, and other signaling components. At normal expression levels, CheW stimulated clockwise rotation, and receptors appeared to enhance this stimulatory effect. At high expression levels, MCPs inhibited clockwise rotation, and CheW appeared to augment this inhibitory effect. Since overexpression of CheW or MCP molecules had the same behavioral effect as their absence, chemoreceptors probably use CheW to modulate two distinct signals, one that stimulates and one that inhibits the intracellular phosphorylation cascade.

Liu, Jingdong; Parkinson, John S.

1989-11-01

57

The Francisella pathogenicity island protein IglA localizes to the bacterial cytoplasm and is needed for intracellular growth  

PubMed Central

Background Francisella tularensis is a gram negative, facultative intracellular bacterium that is the etiological agent of tularemia. F. novicida is closely related to F. tularensis but has low virulence for humans while being highly virulent in mice. IglA is a 21 kDa protein encoded by a gene that is part of an iglABCD operon located on the Francisella pathogenicity island (FPI). Results Bioinformatics analysis of the FPI suggests that IglA and IglB are components of a newly described type VI secretion system. In this study, we showed that IglA regulation is controlled by the global regulators MglA and MglB. During intracellular growth IglA production reaches a maximum at about 10 hours post infection. Biochemical fractionation showed that IglA is a soluble cytoplasmic protein and immunoprecipitation experiments demonstrate that it interacts with the downstream-encoded IglB. When the iglB gene was disrupted IglA could not be detected in cell extracts of F. novicida, although IglC could be detected. We further demonstrated that IglA is needed for intracellular growth of F. novicida. A non-polar iglA deletion mutant was defective for growth in mouse macrophage-like cells, and in cis complementation largely restored the wild type macrophage growth phenotype. Conclusion The results of this study demonstrate that IglA and IglB are interacting cytoplasmic proteins that are required for intramacrophage growth. The significance of the interaction may be to secrete effector molecules that affect host cell processes. PMID:17233889

de Bruin, Olle M; Ludu, Jagjit S; Nano, Francis E

2007-01-01

58

Measuring Intergenerational Obligations  

ERIC Educational Resources Information Center

Researchers have defined intergenerational obligations in diverse ways, and they have used many labels and ways of measuring intergenerational obligations. Using vignettes, we compared responses to questions about what family members should do when another family member needed assistance ("normative obligations") with responses to questions about…

Ganong, Lawrence; Coleman, Marilyn

2005-01-01

59

Identification of New Single Nucleotide Polymorphism-Based Markers for Inter- and Intraspecies Discrimination of Obligate Bacterial Parasites (Pasteuria spp.) of Invertebrates ? †  

PubMed Central

Protein-encoding and 16S rRNA genes of Pasteuria penetrans populations from a wide range of geographic locations were examined. Most interpopulation single nucleotide polymorphisms (SNPs) were detected in the 16S rRNA gene. However, in order to fully resolve all populations, these were supplemented with SNPs from protein-encoding genes in a multilocus SNP typing approach. Examination of individual 16S rRNA gene sequences revealed the occurrence of “cryptic” SNPs which were not present in the consensus sequences of any P. penetrans population. Additionally, hierarchical cluster analysis separated P. penetrans 16S rRNA gene clones into four groups, and one of which contained sequences from the most highly passaged population, demonstrating that it is possible to manipulate the population structure of this fastidious bacterium. The other groups were made from representatives of the other populations in various proportions. Comparison of sequences among three Pasteuria species, namely, P. penetrans, P. hartismeri, and P. ramosa, showed that the protein-encoding genes provided greater discrimination than the 16S rRNA gene. From these findings, we have developed a toolbox for the discrimination of Pasteuria at both the inter- and intraspecies levels. We also provide a model to monitor genetic variation in other obligate hyperparasites and difficult-to-culture microorganisms. PMID:21803895

Mauchline, Tim H.; Knox, Rachel; Mohan, Sharad; Powers, Stephen J.; Kerry, Brian R.; Davies, Keith G.; Hirsch, Penny R.

2011-01-01

60

Identification of new single nucleotide polymorphism-based markers for inter- and intraspecies discrimination of obligate bacterial parasites (Pasteuria spp.) of invertebrates.  

PubMed

Protein-encoding and 16S rRNA genes of Pasteuria penetrans populations from a wide range of geographic locations were examined. Most interpopulation single nucleotide polymorphisms (SNPs) were detected in the 16S rRNA gene. However, in order to fully resolve all populations, these were supplemented with SNPs from protein-encoding genes in a multilocus SNP typing approach. Examination of individual 16S rRNA gene sequences revealed the occurrence of "cryptic" SNPs which were not present in the consensus sequences of any P. penetrans population. Additionally, hierarchical cluster analysis separated P. penetrans 16S rRNA gene clones into four groups, and one of which contained sequences from the most highly passaged population, demonstrating that it is possible to manipulate the population structure of this fastidious bacterium. The other groups were made from representatives of the other populations in various proportions. Comparison of sequences among three Pasteuria species, namely, P. penetrans, P. hartismeri, and P. ramosa, showed that the protein-encoding genes provided greater discrimination than the 16S rRNA gene. From these findings, we have developed a toolbox for the discrimination of Pasteuria at both the inter- and intraspecies levels. We also provide a model to monitor genetic variation in other obligate hyperparasites and difficult-to-culture microorganisms. PMID:21803895

Mauchline, Tim H; Knox, Rachel; Mohan, Sharad; Powers, Stephen J; Kerry, Brian R; Davies, Keith G; Hirsch, Penny R

2011-09-01

61

GRANDPARENTS' ENTITLEMENTS AND OBLIGATIONS  

PubMed Central

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

Draper, Heather

2013-01-01

62

Transposon Mutagenesis of the Obligate Intracellular Pathogen Rickettsia prowazekii  

Microsoft Academic Search

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

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

2004-01-01

63

Obligately barophilic bacterium from the Mariana trench.  

PubMed Central

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

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

1981-01-01

64

Susceptibility of intracellular Coxiella burnetii to antimicrobial peptides in mouse fibroblast cells.  

PubMed

Q fever is a zoonotic disease caused by Coxiella burnetii, an obligate intracellular bacterium that resides inside a phagolysosome-like niche. Chronic Q fever is typified by endocarditis, and is treated with multiple antibiotics for at least 18 months. The discovery of clinical C. burnetii isolates resistant to the first-line antibiotic doxycycline, and the problematic nature of chronic Q fever treatment have demonstrated the need for improved treatment regimes. To search for alternative antimicrobial agents, we assessed the effect of 26 antimicrobial peptides (AMPs) on the intracellular growth of C. burnetii in L929 cells at a concentration of 25 µM or their maximal non-cytotoxic concentration. Among the peptides tested, A3-APO, Cath-BF, ?-Hemolysin, Octa-1, P5 and Pleurocidin were able to significantly reduce both the total bacterial cell number and the host cell bacterial burden (average bacterial number per host cell). Combining selected AMPs with Chariot, a non-covalent carrier peptide, did not increase treatment potency when non-cytotoxic concentrations were used, with the exception of P5, which remained active at a concentration of 1.6 µM (1.8 µg/mL). Combining AMPs with each other did not further improve AMP potency, with some treatment combinations increasing the growth rate of C. burnetii by >3-fold. This is the first description of AMP cellular penetration to exhibit inhibitory affect on intracellular C. burnetii growth. These results are the first step in the development of a non-traditional antibiotic treatment for Q fever. PMID:24364858

Unsworth, Nathan B; Dawson, Raymond M; Wade, John D; Liu, Chun-Qiang

2014-01-01

65

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

SciTech Connect

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.

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

2006-07-21

66

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

PubMed Central

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

2012-01-01

67

Visualization of pseudogenes in intracellular bacteria reveals the different tracks to gene destruction  

Microsoft Academic Search

BACKGROUND: Pseudogenes reveal ancestral gene functions. Some obligate intracellular bacteria, such as Mycobacterium leprae and Rickettsia spp., carry substantial fractions of pseudogenes. Until recently, horizontal gene transfers were considered to be rare events in obligate host-associated bacteria. RESULTS: We present a visualization tool that displays the relationships and positions of degraded and partially overlapping gene sequences in multiple genomes. With

Hans-Henrik Fuxelius; Alistair C Darby; Nam-Huyk Cho; Siv GE Andersson

2008-01-01

68

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

PubMed Central

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. PMID:21525983

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

2011-01-01

69

Studies of polyamine metabolism in obligately alkalophilic Bacillus alcalophilus that grow at pH 11  

SciTech Connect

Bacillus alcalophilus, an obligately alkalophilic bacterium, grow at pH 11 with an intracellular pH greater than 9.5. Polyamines are positively charged at physiological pH, but less than 50% of polyamines will be charged at pH 9.5 and above. In view of the importance of polycationic nature of polyamines in their physiological functions, it is of interest to study the polyamine metabolism in B. alcalophilus, an unusual organism that grow at very high pH. Spermidine is the major polyamine in this organism, accounts for more than 90% of total polyamine. The level of spermidine fluctuates between 10 to 30 nmol per mg protein during growth. In contrast, putrescine and spermine levels stay constant during entire period of growth. No ornithine decarboxylase (DC) activity can be detected in B. alcalophilus under all conditions examined. When (/sup 3/H)arginine was added to the bacterial culture, the distribution of radioactivity in polyamine pool was 3% for putrescine, 94% for spermidine, and 3% for spermine, suggesting the presence of arginine pathway for polyamine biosynthesis. B. alcalophilus appears to possess a polyamine transport system that is Na/sup +/-dependent. Putrescine uptake in B. alcalophilus is sensitive to the inhibition of gramicidine S (10 ..mu..M) and valinomycin (2..mu..M).

Cheng, S.; Chen, K.Y.

1987-05-01

70

Population dynamics of obligate cooperators  

PubMed Central

Obligate cooperative breeding species demonstrate a high rate of group extinction, which may be due to the existence of a critical number of helpers below which the group cannot subsist. Through a simple model, we study the population dynamics of obligate cooperative breeding species, taking into account the existence of a lower threshold below which the instantaneous growth rate becomes negative. The model successively incorporates (i) a distinction between species that need helpers for reproduction, survival or both, (ii) the existence of a migration rate accounting for dispersal, and (iii) stochastic mortality to simulate the effects of random catastrophic events. Our results suggest that the need for a minimum number of helpers increases the risk of extinction for obligate cooperative breeding species. The constraint imposed by this threshold is higher when helpers are needed for reproduction only or for both reproduction and survival. By driving them below this lower threshold, stochastic mortality of lower amplitude and/or lower frequency than for non-cooperative breeders may be sufficient to cause the extinction of obligate cooperative breeding groups. Migration may have a buffering effect only for groups where immigration is higher than emigration; otherwise (when immigrants from nearby groups are not available) it lowers the difference between actual group size and critical threshold, thereby constituting a higher constraint.

Courchamp, F.; Grenfell, B.; Clutton-Brock, T.

1999-01-01

71

38 CFR 17.607 - Obligated service.  

Code of Federal Regulations, 2010 CFR

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

2010-07-01

72

38 CFR 17.607 - Obligated service.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

73

38 CFR 17.607 - Obligated service.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

74

38 CFR 17.607 - Obligated service.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

75

17 CFR 200.54 - Constitutional obligations.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Constitutional obligations. 200.54 Section... Canons of Ethics § 200.54 Constitutional obligations. The members...guard against any infringement of the constitutional rights, privileges, or...

2010-04-01

76

5 CFR 724.302 - Reporting obligations.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Reporting obligations. 724... OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL...Report § 724.302 Reporting obligations. ...by April 25, 2007. Future reports must include...Office of Personnel...

2010-01-01

77

Federal Academic Science and Engineering Obligations Decreased  

NSF Publications Database

Federal Academic Science and Engineering Obligations Decreased Slightly in FY 1996 (April 27, 1998 ... findings on academic S&E obligations for Fiscal Year 1996. A full set of Detailed Statistical Tables ...

78

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

PubMed Central

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

Chong, Audrey; Celli, Jean

2010-01-01

79

Azithromycin effectiveness against intracellular infections of Francisella  

Microsoft Academic Search

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

Saira Ahmad; Lyman Hunter; Aiping Qin; Barbara J Mann; Monique L van Hoek

2010-01-01

80

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

PubMed

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

Fan, Yongliang; Wernegreen, Jennifer J

2013-10-01

81

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

PubMed Central

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

Fan, Yongliang; Wernegreen, Jennifer J.

2014-01-01

82

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

PubMed Central

Determining the transient chemical properties of the intracellular environment can elucidate the paths through which a biological system adapts to changes in its environment, for example, the mechanisms that enable some obligate anaerobic bacteria to survive a sudden exposure to oxygen. Here we used high-resolution Fourier transform infrared (FTIR) spectromicroscopy to continuously follow cellular chemistry within living obligate anaerobes by monitoring hydrogen bond structures in their cellular water. We observed a sequence of well orchestrated molecular events that correspond to changes in cellular processes in those cells that survive, but only accumulation of radicals in those that do not. We thereby can interpret the adaptive response in terms of transient intracellular chemistry and link it to oxygen stress and survival. This ability to monitor chemical changes at the molecular level can yield important insights into a wide range of adaptive responses. PMID:19541631

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

2009-01-01

83

Collectivizing rescue obligations in bioethics.  

PubMed

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

Garrett, Jeremy R

2015-02-01

84

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

E-print Network

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

Xing, Bengang

85

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

PubMed Central

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

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

2013-01-01

86

38 CFR 17.607 - Obligated service.  

Code of Federal Regulations, 2014 CFR

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

2014-07-01

87

31 CFR 225.5 - Pledge of definitive Government obligations.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

88

31 CFR 225.5 - Pledge of definitive Government obligations.  

Code of Federal Regulations, 2014 CFR

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

2014-07-01

89

31 CFR 225.5 - Pledge of definitive Government obligations.  

Code of Federal Regulations, 2010 CFR

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

2010-07-01

90

31 CFR 225.5 - Pledge of definitive Government obligations.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

91

31 CFR 225.5 - Pledge of definitive Government obligations.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

92

49 CFR 22.17 - Compliance with child support obligations.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Compliance with child support obligations. 22.17 Section... § 22.17 Compliance with child support obligations. Any holder...delinquent on any obligation to pay child support arising under: (a) An...

2010-10-01

93

28 CFR 811.3 - Notice of obligation to register.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Notice of obligation to register. 811.3 Section 811.3 Judicial...811.3 Notice of obligation to register. (a) Sex offenders may be notified of their obligation to register under various provisions...

2010-07-01

94

18 CFR 292.311 - Reinstatement of obligation to purchase.  

Code of Federal Regulations, 2010 CFR

...Reinstatement of obligation to purchase. 292.311 Section 292...Reinstatement of obligation to purchase. At any time after the Commission makes a...utility of its obligation to purchase electric energy, a...

2010-04-01

95

18 CFR 292.311 - Reinstatement of obligation to purchase.  

Code of Federal Regulations, 2013 CFR

...Reinstatement of obligation to purchase. 292.311 Section 292...Reinstatement of obligation to purchase. At any time after the Commission makes a...utility of its obligation to purchase electric energy, a...

2013-04-01

96

18 CFR 292.311 - Reinstatement of obligation to purchase.  

Code of Federal Regulations, 2012 CFR

...Reinstatement of obligation to purchase. 292.311 Section 292...Reinstatement of obligation to purchase. At any time after the Commission makes a...utility of its obligation to purchase electric energy, a...

2012-04-01

97

18 CFR 292.311 - Reinstatement of obligation to purchase.  

Code of Federal Regulations, 2011 CFR

...Reinstatement of obligation to purchase. 292.311 Section 292...Reinstatement of obligation to purchase. At any time after the Commission makes a...utility of its obligation to purchase electric energy, a...

2011-04-01

98

18 CFR 292.311 - Reinstatement of obligation to purchase.  

Code of Federal Regulations, 2014 CFR

...Reinstatement of obligation to purchase. 292.311 Section 292...Reinstatement of obligation to purchase. At any time after the Commission makes a...utility of its obligation to purchase electric energy, a...

2014-04-01

99

Strategies for Intracellular Survival of Burkholderia pseudomallei  

PubMed Central

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

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

2011-01-01

100

45 CFR 2400.65 - Teaching obligation.  

Code of Federal Regulations, 2011 CFR

...Teaching obligation. Upon receiving a Master's degree, each Fellow must teach American history, American government, social studies, or political science on a full-time basis to students in secondary school for a period of not less than one...

2011-10-01

101

45 CFR 2400.65 - Teaching obligation.  

Code of Federal Regulations, 2010 CFR

...Teaching obligation. Upon receiving a Master's degree, each Fellow must teach American history, American government, social studies, or political science on a full-time basis to students in secondary school for a period of not less than one...

2010-10-01

102

19 CFR 10.412 - Importer obligations.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

103

19 CFR 10.412 - Importer obligations.  

Code of Federal Regulations, 2011 CFR

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

2011-04-01

104

19 CFR 10.412 - Importer obligations.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

105

19 CFR 10.412 - Importer obligations.  

Code of Federal Regulations, 2012 CFR

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

2012-04-01

106

19 CFR 10.412 - Importer obligations.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

107

19 CFR 10.865 - Importer obligations.  

Code of Federal Regulations, 2013 CFR

...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Oman Free Trade Agreement Import Requirements § 10.865 Importer obligations. (a) General. An importer who makes...

2013-04-01

108

19 CFR 10.865 - Importer obligations.  

Code of Federal Regulations, 2011 CFR

...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Oman Free Trade Agreement Import Requirements § 10.865 Importer obligations. (a) General. An importer who makes...

2011-04-01

109

19 CFR 10.865 - Importer obligations.  

Code of Federal Regulations, 2012 CFR

...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Oman Free Trade Agreement Import Requirements § 10.865 Importer obligations. (a) General. An importer who makes...

2012-04-01

110

19 CFR 10.865 - Importer obligations.  

Code of Federal Regulations, 2014 CFR

...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Oman Free Trade Agreement Import Requirements § 10.865 Importer obligations. (a) General. An importer who makes...

2014-04-01

111

38 CFR 17.632 - Obligated service.  

Code of Federal Regulations, 2014 CFR

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

2014-07-01

112

Naval Engineering A National Naval Obligation  

E-print Network

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

Chryssostomidis, Chryssostomos

2000-05-16

113

46 CFR Sec. 11 - Guarantee obligations.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

114

46 CFR Sec. 11 - Guarantee obligations.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

115

46 CFR Sec. 11 - Guarantee obligations.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

116

46 CFR Sec. 11 - Guarantee obligations.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

117

46 CFR Sec. 11 - Guarantee obligations.  

Code of Federal Regulations, 2014 CFR

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

2014-10-01

118

19 CFR 10.705 - Importer obligations.  

Code of Federal Regulations, 2010 CFR

...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Jordan Free Trade Agreement Import Requirements § 10.705 Importer obligations. (a) General. An importer who...

2010-04-01

119

19 CFR 10.705 - Importer obligations.  

Code of Federal Regulations, 2013 CFR

...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Jordan Free Trade Agreement Import Requirements § 10.705 Importer obligations. (a) General. An importer who...

2013-04-01

120

19 CFR 10.705 - Importer obligations.  

Code of Federal Regulations, 2011 CFR

...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Jordan Free Trade Agreement Import Requirements § 10.705 Importer obligations. (a) General. An importer who...

2011-04-01

121

19 CFR 10.705 - Importer obligations.  

Code of Federal Regulations, 2014 CFR

...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Jordan Free Trade Agreement Import Requirements § 10.705 Importer obligations. (a) General. An importer who...

2014-04-01

122

19 CFR 10.705 - Importer obligations.  

Code of Federal Regulations, 2012 CFR

...HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Jordan Free Trade Agreement Import Requirements § 10.705 Importer obligations. (a) General. An importer who...

2012-04-01

123

The intracellular bacteria Chlamydia hijack peroxisomes and utilize their enzymatic capacity to produce bacteria-specific phospholipids.  

PubMed

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

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

2014-01-01

124

Advanced Review Theoretical insights into bacterial  

E-print Network

1 | A schematic comparison of the intracellular signaling pathways and related components (receptor:247­259. doi: 10.1002/wsbm.1168 BASICS OF BACTERIAL CHEMOTAXIS Chemotactic bacteria are usually small rod intracellular response systems as they are too small to sense changes in their biochemical environment along

Maini, Philip K.

125

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

PubMed Central

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

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

2012-01-01

126

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

PubMed

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

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

2014-02-01

127

Toward Intracellular Targeted Delivery of Cancer Therapeutics  

PubMed Central

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

Pandya, Hetal; Debinski, Waldemar

2013-01-01

128

Patients' ethical obligation for their health.  

PubMed Central

In contemporary medical ethics health is rarely acknowledged to be an ethical obligation. This oversight is due to the preoccupation of most bioethicists with a rationalist, contract model for ethics in which moral obligation is limited to truth-telling and promise-keeping. Such an ethics is poorly suited to medicine because it fails to appreciate that medicine's basis as a moral enterprise is oriented towards health values. A naturalistic model for medical ethics is proposed which builds upon biological and medical values. This perspective clarifies ethical obligations to ourselves and to others for life and health. It provides a normative framework for the doctor-patient relationship within which to formulate medical advice and by which to evaluate patient choice. PMID:6502640

Sider, R C; Clements, C D

1984-01-01

129

Neutrophils Mediate Immunopathology and Negatively Regulate Protective Immune Responses during Fatal Bacterial Infection-Induced Toxic Shock  

PubMed Central

Ehrlichia chaffeensis is an obligate intracellular bacterium that infects primarily monocytes and macrophages and causes potentially fatal human monocytic ehrlichiosis (HME) that mimics toxic-shock-like syndrome in immunocompetent hosts. Early recruitment of neutrophils to the sites of infection is critical for the control of bacterial infection and inflammatory responses. We recently observed rapid and sustained neutrophil recruitment at a primary site of infection (peritoneum) following lethal murine ehrlichial infection compared to innocuous ehrlichial infection. We examined here the contribution of neutrophils to protective immunity or immunopathology during infection with monocytic Ehrlichia. Unexpectedly, depletion of neutrophils from lethally infected mice enhanced bacterial elimination, decreased immune-mediated pathology, and prolonged survival. Furthermore, compared to lethally infected sham controls, neutrophil depletion in infected mice resulted in amelioration of pathogenic responses, as evidenced by a decreased number of tumor necrosis factor alpha (TNF-?)-producing CD8+ T cells, which is known to mediate immunopathology and toxic shock in a murine model of fatal ehrlichiosis. Although neutrophil depletion did not influence the number of CD4+ Th1 cells and NKT cells producing gamma interferon (IFN-?), it increased the ratio of IFN-?- to IL-10-producing NKT cells as well as the ratio of IFN-? to interleukin 10 (IL-10) transcripts in the liver. This may ameliorate the net suppressive effect of IL-10 on IFN-?-mediated activation of infected macrophages and thus may account for the enhanced bacterial elimination. Finally, transcriptional analysis of gene expression in the liver indicated that neutrophils contribute to overproduction of cytokines and chemokines during fatal ehrlichiosis. In conclusion, these results revealed an unexpected role of neutrophils in supporting bacterial replication indirectly and promoting immunopathology during severe infection with an intracellular bacterium. PMID:23478316

Yang, Qin; Ghose, Purnima

2013-01-01

130

Bacterial thermotaxis by speed modulation  

NASA Astrophysics Data System (ADS)

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

Demir, Mahmut

131

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

PubMed Central

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

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

2014-01-01

132

Professional obligations, employment responsibilities and collective bargaining  

Microsoft Academic Search

Labour relations scholars have been discussing the proper relationship between professional obligations and collective bargaining at least since Shirley Goldenberg's study for the 1968 Task Force on Industrial Relations. The positions taken have ranged from rabid assertions that professionalism can flower only in a rarefied atmosphere graced with a pupil\\/teacher ratio lower than 12:1 to a recent solemn declaration by

Kenneth P. Swan

1978-01-01

133

The author’s opportunity and obligation  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

134

Classroom Curriculum: Balancing Autonomy and Obligation.  

ERIC Educational Resources Information Center

This study investigated the influences shaping the curriculum decision-making process of four English teachers in two middle schools in order to identify sources of professional autonomy and obligation in classroom curriculum. These teachers made decisions daily by selecting content, texts and materials, modes of presentation, learning activities,…

Hawthorne, Rebecca Killen

135

Chloride Channels of Intracellular Membranes  

PubMed Central

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

Edwards, John C.; Kahl, Christina R.

2010-01-01

136

47 CFR 80.105 - General obligations of coast stations.  

Code of Federal Regulations, 2010 CFR

... false General obligations of coast stations. 80.105 Section 80.105 Telecommunication... SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Operating...Procedures Operating Procedures-Land Stations § 80.105 General obligations...

2010-10-01

137

7 CFR 4274.355 - Loan approval and obligating funds.  

Code of Federal Regulations, 2010 CFR

...false Loan approval and obligating funds. 4274.355 Section 4274.355 Agriculture Regulations of the Department of Agriculture... Intermediary Relending Program (IRP) § 4274.355 Loan approval and obligating funds. The...

2010-01-01

138

47 CFR 24.247 - Triggering a reimbursement obligation.  

Code of Federal Regulations, 2010 CFR

...false Triggering a reimbursement obligation. 24.247 Section 24.247 Telecommunication FEDERAL COMMUNICATIONS COMMISSION...Microwave Relocation from the 1850-1990 Mhz Band § 24.247 Triggering a reimbursement obligation. (a)...

2010-10-01

139

23 CFR 450.332 - Annual listing of obligated projects.  

Code of Federal Regulations, 2010 CFR

...listing of obligated projects. 450.332 ...TRANSPORTATION PLANNING AND RESEARCH PLANNING...Metropolitan Transportation Planning and Programming...listing of obligated projects. (a) In metropolitan planning areas, on...

2010-04-01

140

23 CFR 450.332 - Annual listing of obligated projects.  

Code of Federal Regulations, 2011 CFR

...listing of obligated projects. 450.332 ...TRANSPORTATION PLANNING AND RESEARCH PLANNING...Metropolitan Transportation Planning and Programming...listing of obligated projects. (a) In metropolitan planning areas, on...

2011-04-01

141

47 CFR 90.673 - Obligation to abate unacceptable interference.  

Code of Federal Regulations, 2011 CFR

... Obligation to abate unacceptable interference. 90.673 Section 90.673 Telecommunication...Procedures and Process-Unacceptable Interference § 90.673 Obligation to abate unacceptable interference. (a) Strict...

2011-10-01

142

47 CFR 22.971 - Obligation to abate unacceptable interference.  

Code of Federal Regulations, 2014 CFR

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

2014-10-01

143

47 CFR 22.971 - Obligation to abate unacceptable interference.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

144

47 CFR 22.971 - Obligation to abate unacceptable interference.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

145

47 CFR 22.878 - Obligation to abate unacceptable interference.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

146

47 CFR 90.673 - Obligation to abate unacceptable interference.  

Code of Federal Regulations, 2013 CFR

... Obligation to abate unacceptable interference. 90.673 Section 90.673 Telecommunication...Procedures and Process-Unacceptable Interference § 90.673 Obligation to abate unacceptable interference. (a) Strict...

2013-10-01

147

47 CFR 22.878 - Obligation to abate unacceptable interference.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

148

47 CFR 22.878 - Obligation to abate unacceptable interference.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

149

47 CFR 22.878 - Obligation to abate unacceptable interference.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

150

47 CFR 90.673 - Obligation to abate unacceptable interference.  

Code of Federal Regulations, 2010 CFR

... Obligation to abate unacceptable interference. 90.673 Section 90.673 Telecommunication...Procedures and Process-Unacceptable Interference § 90.673 Obligation to abate unacceptable interference. (a) Strict...

2010-10-01

151

47 CFR 22.878 - Obligation to abate unacceptable interference.  

Code of Federal Regulations, 2014 CFR

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

2014-10-01

152

47 CFR 90.673 - Obligation to abate unacceptable interference.  

Code of Federal Regulations, 2012 CFR

... Obligation to abate unacceptable interference. 90.673 Section 90.673 Telecommunication...Procedures and Process-Unacceptable Interference § 90.673 Obligation to abate unacceptable interference. (a) Strict...

2012-10-01

153

47 CFR 22.971 - Obligation to abate unacceptable interference.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

154

47 CFR 22.971 - Obligation to abate unacceptable interference.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

155

22 CFR 221.15 - Fiscal Agent obligations.  

Code of Federal Regulations, 2011 CFR

... AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEE STANDARD TERMS...Agent obligations. Failure of the Fiscal Agent to perform any of its obligations pursuant...Guarantee, but may be the subject of action for damages...

2011-04-01

156

22 CFR 221.15 - Fiscal Agent obligations.  

Code of Federal Regulations, 2013 CFR

... AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEE STANDARD TERMS...Agent obligations. Failure of the Fiscal Agent to perform any of its obligations pursuant...Guarantee, but may be the subject of action for damages...

2013-04-01

157

22 CFR 230.07 - Fiscal Agent obligations.  

Code of Federal Regulations, 2014 CFR

... AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEES ISSUED UNDER...SUPPLEMENTAL APPROPRIATIONS ACT OF 2003, PUB. L. 108-11-STANDARD...Agent obligations. Failure of the Fiscal Agent to perform any of its obligations...

2014-04-01

158

22 CFR 221.15 - Fiscal Agent obligations.  

Code of Federal Regulations, 2010 CFR

... AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEE STANDARD TERMS...Agent obligations. Failure of the Fiscal Agent to perform any of its obligations pursuant...Guarantee, but may be the subject of action for damages...

2010-04-01

159

22 CFR 230.07 - Fiscal Agent obligations.  

Code of Federal Regulations, 2010 CFR

... AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEES ISSUED UNDER...SUPPLEMENTAL APPROPRIATIONS ACT OF 2003, PUB. L. 108-11-STANDARD...Agent obligations. Failure of the Fiscal Agent to perform any of its obligations...

2010-04-01

160

22 CFR 221.15 - Fiscal Agent obligations.  

Code of Federal Regulations, 2014 CFR

... AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEE STANDARD TERMS...Agent obligations. Failure of the Fiscal Agent to perform any of its obligations pursuant...Guarantee, but may be the subject of action for damages...

2014-04-01

161

22 CFR 230.07 - Fiscal Agent obligations.  

Code of Federal Regulations, 2013 CFR

... AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEES ISSUED UNDER...SUPPLEMENTAL APPROPRIATIONS ACT OF 2003, PUB. L. 108-11-STANDARD...Agent obligations. Failure of the Fiscal Agent to perform any of its obligations...

2013-04-01

162

22 CFR 230.07 - Fiscal Agent obligations.  

Code of Federal Regulations, 2011 CFR

... AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEES ISSUED UNDER...SUPPLEMENTAL APPROPRIATIONS ACT OF 2003, PUB. L. 108-11-STANDARD...Agent obligations. Failure of the Fiscal Agent to perform any of its obligations...

2011-04-01

163

22 CFR 221.15 - Fiscal Agent obligations.  

Code of Federal Regulations, 2012 CFR

... AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEE STANDARD TERMS...Agent obligations. Failure of the Fiscal Agent to perform any of its obligations pursuant...Guarantee, but may be the subject of action for damages...

2012-04-01

164

22 CFR 230.07 - Fiscal Agent obligations.  

Code of Federal Regulations, 2012 CFR

... AGENCY FOR INTERNATIONAL DEVELOPMENT ISRAEL LOAN GUARANTEES ISSUED UNDER...SUPPLEMENTAL APPROPRIATIONS ACT OF 2003, PUB. L. 108-11-STANDARD...Agent obligations. Failure of the Fiscal Agent to perform any of its obligations...

2012-04-01

165

Intracellular mechanisms of aminoglycoside-induced cytotoxicity  

PubMed Central

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

Karasawa, Takatoshi; Steyger, Peter S.

2013-01-01

166

Prostatitis - bacterial  

MedlinePLUS

Prostatitis is most often caused by a bacterial infection of the prostate gland. Any bacteria that can cause a urinary tract infection can cause acute bacterial prostatitis. Some sexually transmitted diseases (STDs) ...

167

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

168

Unveiling the Intracellular Survival Gene Kit of Trypanosomatid Parasites  

PubMed Central

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

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

2014-01-01

169

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

Code of Federal Regulations, 2014 CFR

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

2014-07-01

170

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

171

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

172

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

173

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

174

Bacterial Sialidase  

NASA Technical Reports Server (NTRS)

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

2004-01-01

175

Informed consent: Enforcing pharmaceutical companies' obligations abroad.  

PubMed

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

Lee, Stacey B

2010-01-01

176

Ecophysiological Characteristics of Obligate Methanotrophic Bacteria and Methane Oxidation In Situ  

NASA Technical Reports Server (NTRS)

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

King, Gary M.

1993-01-01

177

A New Role of the Complement System: C3 Provides Protection in a Mouse Model of Lung Infection with Intracellular Chlamydia psittaci  

PubMed Central

The complement system modulates the intensity of innate and specific immunity. While it protects against infections by extracellular bacteria its role in infection with obligate intracellular bacteria, such as the avian and human pathogen Chlamydia (C.) psittaci, is still unknown. In the present study, knockout mice lacking C3 and thus all main complement effector functions were intranasally infected with C. psittaci strain DC15. Clinical parameters, lung histology, and cytokine levels were determined. A subset of infections was additionally performed with mice lacking C5 or C5a receptors. Complement activation occurred before symptoms of pneumonia appeared. Mice lacking C3 were ?100 times more susceptible to the intracellular bacteria compared to wild-type mice, with all C3?/? mice succumbing to infection after day 9. At a low infective dose, C3?/? mice became severely ill after an even longer delay, the kinetics suggesting a so far unknown link of complement to the adaptive, protective immune response against chlamydiae. The lethal phenotype of C3?/? mice is not based on differences in the anti-chlamydial IgG response (which is slightly delayed) as demonstrated by serum transfer experiments. In addition, during the first week of infection, the absence of C3 was associated with partial protection characterized by reduced weight loss, better clinical score and lower bacterial burden, which might be explained by a different mechanism. Lack of complement functions downstream of C5 had little effect. This study demonstrates for the first time a strong and complex influence of complement effector functions, downstream of C3 and upstream of C5, on the outcome of an infection with intracellular bacteria, such as C. psittaci. PMID:23189195

Bode, Jenny; Dutow, Pavel; Sommer, Kirsten; Janik, Katrin; Glage, Silke; Tümmler, Burkhard; Munder, Antje; Laudeley, Robert; Sachse, Konrad W.; Klos, Andreas

2012-01-01

178

A new role of the complement system: C3 provides protection in a mouse model of lung infection with intracellular Chlamydia psittaci.  

PubMed

The complement system modulates the intensity of innate and specific immunity. While it protects against infections by extracellular bacteria its role in infection with obligate intracellular bacteria, such as the avian and human pathogen Chlamydia (C.) psittaci, is still unknown. In the present study, knockout mice lacking C3 and thus all main complement effector functions were intranasally infected with C. psittaci strain DC15. Clinical parameters, lung histology, and cytokine levels were determined. A subset of infections was additionally performed with mice lacking C5 or C5a receptors. Complement activation occurred before symptoms of pneumonia appeared. Mice lacking C3 were ?100 times more susceptible to the intracellular bacteria compared to wild-type mice, with all C3(-/-) mice succumbing to infection after day 9. At a low infective dose, C3(-/-) mice became severely ill after an even longer delay, the kinetics suggesting a so far unknown link of complement to the adaptive, protective immune response against chlamydiae. The lethal phenotype of C3(-/-) mice is not based on differences in the anti-chlamydial IgG response (which is slightly delayed) as demonstrated by serum transfer experiments. In addition, during the first week of infection, the absence of C3 was associated with partial protection characterized by reduced weight loss, better clinical score and lower bacterial burden, which might be explained by a different mechanism. Lack of complement functions downstream of C5 had little effect. This study demonstrates for the first time a strong and complex influence of complement effector functions, downstream of C3 and upstream of C5, on the outcome of an infection with intracellular bacteria, such as C. psittaci. PMID:23189195

Bode, Jenny; Dutow, Pavel; Sommer, Kirsten; Janik, Katrin; Glage, Silke; Tümmler, Burkhard; Munder, Antje; Laudeley, Robert; Sachse, Konrad W; Klos, Andreas

2012-01-01

179

Phenotypic signatures arising from unbalanced bacterial growth.  

PubMed

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

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

2014-08-01

180

Phenotypic Signatures Arising from Unbalanced Bacterial Growth  

PubMed Central

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

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

2014-01-01

181

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

PubMed Central

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

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

2012-01-01

182

Experimental evolution of nodule intracellular infection in legume symbionts.  

PubMed

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

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

2013-07-01

183

Verifying nonproliferation treaties: Obligation, process, and sovereignty  

SciTech Connect

The foregoing chapters examine what verification is and why states would bother with so difficult and politically sensitive an issue when negotiating agreements on arms control and disarmament issues. Now it is necessary to confront the question of whether there are any meaningful conclusions to be drawn from this exercise. Are the patterns discerned in the history of these treaties meaningful for understanding how other treaties have evolved or will evolve. Are there lessons here which might benefit future negotiators. This final chapter seeks to provide some answers, albeit partial ones, to these questions. There are in fact several interesting and potentially important conclusions to be drawn. Verification of multilateral treaty obligations contains its own intrinsic structure and logic, independent of the obligations undertaken by the parties and the political context in which those undertakings are negotiated and made. The many significant similarities in the verification processes for the CFE Treaty, the NPT, and the CWC demonstrate the degree to which there is such an underlying structure regardless of whether the behavior or activity is strictly military or has essentially civilian dimensions, whether all relevant states participate or only some of the most important states agree from the beginning to participate, and whether the agreement is global or regional in scope.

Kessler, J.C.

1995-10-01

184

23 CFR 230.205 - Supportive services funds obligation.  

Code of Federal Regulations, 2010 CFR

... FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS EXTERNAL PROGRAMS Supportive Services for Minority, Disadvantaged, and Women Business Enterprises § 230.205 Supportive services funds obligation. Supportive...

2010-04-01

185

[Using of antibodies against Microsporia Hsp70 family proteins for analysis of secretome of intracellular parasites].  

PubMed

Microsporidia is a large group of fungi-related unicellular parasites with obligate intracellular lifestyle. Unlike other protozoan intracellular parasites (Kinetoplastida and Apicomplexa), most microsporidian species develop in direct contact with the host cell cytoplasm. This fact, acquisition of unique transporters to exploit host metabolic system (alongside the strong minimization of own machinery) and predicted repertoire of microsporidia secretome altogether suggest an active role of parasite proteins in the control of infected cell. Lack of information about secretome of microsporidia intracellular stages is largely due to the methodological difficulties of working with the obligate intracellular parasites. An important problem of such study is the contamination of preparations of host cell cytoplasm by inner (nonsecreted) parasite proteins. Even the homogenization of infected tissue in mild conditions and removal of parasite cells by low-speed centrifugation may result in their partial disruption. We expressed the fragments of three Hsp70 family chaperones from the microsporidium Paranosema (Antonospora) locustae in bacteria Escherichia coli. Immunoblotting with proteins of microsporidia intracellular stages and infected host tissue (locust fat bodies) demonstrated that antibodies against recombinant polypeptides may be used to monitor the integrity of parasite cells during homogenization of infected host tissue and subsequent removal of parasites by centrifugation. PMID:23458023

Dolgikh, V V; Senderski?, I V; Pavlova, O A; Timofeev, S A; Naumov, A M

2012-01-01

186

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

PubMed Central

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

Sloan, Daniel B.; Moran, Nancy A.

2012-01-01

187

Pharmacological Inhibition of the ClpXP Protease Increases Bacterial Susceptibility to Host Cathelicidin Antimicrobial Peptides and Cell  

E-print Network

bacterial virulence factors rather than directly target growth or survival in the manner of traditionalPharmacological Inhibition of the ClpXP Protease Increases Bacterial Susceptibility to Host is a critical bacterial intracellular protease that regulates protein turnover in many bacterial species. Here

Nizet, Victor

188

Quantitative Proteomics of Intracellular Campylobacter jejuni Reveals Metabolic Reprogramming  

PubMed Central

Campylobacter jejuni is the major cause of bacterial food-borne illness in the USA and Europe. An important virulence attribute of this bacterial pathogen is its ability to enter and survive within host cells. Here we show through a quantitative proteomic analysis that upon entry into host cells, C. jejuni undergoes a significant metabolic downshift. Furthermore, our results indicate that intracellular C. jejuni reprograms its respiration, favoring the respiration of fumarate. These results explain the poor ability of C. jejuni obtained from infected cells to grow under standard laboratory conditions and provide the bases for the development of novel anti microbial strategies that would target relevant metabolic pathways. PMID:22412372

Liu, Xiaoyun; Gao, Beile; Novik, Veronica; Galán, Jorge E.

2012-01-01

189

Metabolic Complementarity and Genomics of the Dual Bacterial Symbiosis of Sharpshooters  

PubMed Central

Mutualistic intracellular symbiosis between bacteria and insects is a widespread phenomenon that has contributed to the global success of insects. The symbionts, by provisioning nutrients lacking from diets, allow various insects to occupy or dominate ecological niches that might otherwise be unavailable. One such insect is the glassy-winged sharpshooter (Homalodisca coagulata), which feeds on xylem fluid, a diet exceptionally poor in organic nutrients. Phylogenetic studies based on rRNA have shown two types of bacterial symbionts to be coevolving with sharpshooters: the gamma-proteobacterium Baumannia cicadellinicola and the Bacteroidetes species Sulcia muelleri. We report here the sequencing and analysis of the 686,192–base pair genome of B. cicadellinicola and approximately 150 kilobase pairs of the small genome of S. muelleri, both isolated from H. coagulata. Our study, which to our knowledge is the first genomic analysis of an obligate symbiosis involving multiple partners, suggests striking complementarity in the biosynthetic capabilities of the two symbionts: B. cicadellinicola devotes a substantial portion of its genome to the biosynthesis of vitamins and cofactors required by animals and lacks most amino acid biosynthetic pathways, whereas S. muelleri apparently produces most or all of the essential amino acids needed by its host. This finding, along with other results of our genome analysis, suggests the existence of metabolic codependency among the two unrelated endosymbionts and their insect host. This dual symbiosis provides a model case for studying correlated genome evolution and genome reduction involving multiple organisms in an intimate, obligate mutualistic relationship. In addition, our analysis provides insight for the first time into the differences in symbionts between insects (e.g., aphids) that feed on phloem versus those like H. coagulata that feed on xylem. Finally, the genomes of these two symbionts provide potential targets for controlling plant pathogens such as Xylella fastidiosa, a major agroeconomic problem, for which H. coagulata and other sharpshooters serve as vectors of transmission. PMID:16729848

Wu, Dongying; Daugherty, Sean C; Van Aken, Susan E; Pai, Grace H; Watkins, Kisha L; Khouri, Hoda; Tallon, Luke J; Zaborsky, Jennifer M; Dunbar, Helen E; Tran, Phat L; Moran, Nancy A

2006-01-01

190

An Ultrasensitive Bacterial Motor Revealed by Monitoring  

E-print Network

of the intracellular concentration of the chemotactic signaling protein. The concentration of this molecule, fusedAn Ultrasensitive Bacterial Motor Revealed by Monitoring Signaling Proteins in Single Cells different bacteria exhibited an identical steep input-output relation, sug- gesting that they actively

Cluzel, Philippe

191

Design Principles of a Bacterial Signalling Network  

E-print Network

Design Principles of a Bacterial Signalling Network Why is chemotaxis more complicated than needed of intracellularunderstanding of intracellular signalingsignaling who? who? identification identification how? how ­ The Phenomenon · Bacteria sense nutrient gradients over four orders of magnidute of absolute concentration

Timmer, Jens

192

Design Principles of a Bacterial Signalling Network  

E-print Network

Design Principles of a Bacterial Signalling Network Why is chemotaxis more complicated than needed to answer for theQuestion to answer for the understanding of intracellularunderstanding of intracellular · Bacteria sense nutrient gradients over four orders of magnidute of absolute concentration · Detect relative

Timmer, Jens

193

Genetic ignorance, moral obligations and social duties.  

PubMed

In a contribution to The Journal of Medicine and Philosophy, Professor Rosamond Rhodes argues that individuals sometimes have an obligation to know about their genetic disorders, because this is required by their status as autonomous persons. Her analysis, which is based on Kant's concept of autonomy and Aristotle's notion of friendship, is extended here to consequentialist concerns. These are of paramount importance if, as we believe and Professor Rhodes herself implies, the Kantian and Aristotelian doctrines can be helpful only in the sphere of private morality, not in the public realm. Better tools for assessing the right to genetic ignorance as an issue of public policy can, we contend, be found in Mill's ideas concerning liberty and the prevention of harm. Our own conclusion, based on the Millian way of thinking, is that individuals probably do have the right to remain in ignorance in the cases Professor Rhodes presents as examples of a duty to know. PMID:10732878

Takala, T; Häyry, M

2000-02-01

194

Intracellular starch formation in corynebacteria.  

PubMed

Carrier, E. Bernard (Louisiana State University, Baton Rouge, La.) and C. S. McCleskey. Intracellular starch formation in cor-yne bacteria. J. Bacteriol. 83:1029-1036. 1962.-Cor-ynebacterium tritici, C. striatum, C. renale, and C. pseudodiphtheriticum produce an intracellular starch-like material when grown on native starches; glucose-1-phosphate, mono-, di-, and trisaccharides do not serve as substrates for intracellular starch formation. C. pseudotuberculosis and C. kutscheri produce intracellular starch from starch substrates and glucose-1-phosphate. C. diphtheriae produces starch from glucose-1-phosphate only. PMID:13876866

CARRIER, E B; McCLESKEY, C S

1962-05-01

195

INTRACELLULAR STARCH FORMATION IN CORYNEBACTERIA  

PubMed Central

Carrier, E. Bernard (Louisiana State University, Baton Rouge, La.) and C. S. McCleskey. Intracellular starch formation in cor-yne bacteria. J. Bacteriol. 83:1029–1036. 1962.—Cor-ynebacterium tritici, C. striatum, C. renale, and C. pseudodiphtheriticum produce an intracellular starch-like material when grown on native starches; glucose-1-phosphate, mono-, di-, and trisaccharides do not serve as substrates for intracellular starch formation. C. pseudotuberculosis and C. kutscheri produce intracellular starch from starch substrates and glucose-1-phosphate. C. diphtheriae produces starch from glucose-1-phosphate only. Images PMID:13876866

Carrier, E. Bernard; McCleskey, C. S.

1962-01-01

196

Eosinophil intracellular signalling: apoptosis.  

PubMed

Eosinophil apoptosis is considered critical for the resolution of eosinophilic inflammation in the airways of asthmatics. Apoptosis can be mediated by an extrinsic receptor-activated pathway or alternatively by an intrinsic pathway via distortion of mitochondrial function. Both of these pathways lead to activation of the caspase cascade resulting in degradation of cellular components. We describe here two methods to explore intracellular mechanisms mediating eosinophil apoptosis. Eosinophil staining by fluorescent probe JC-1 followed by flow cytometric analysis is a reliable method for determination of the state of mitochondrial membrane potential (??m). Lost ??m indicates distorted mitochondrial function and apoptosis. We also describe a method to explore the activation of effector caspase-6 by assessing degradation of its substrate lamin A/C by immunoblotting. PMID:24986608

Ilmarinen, Pinja; Moilanen, Eeva; Kankaanranta, Hannu

2014-01-01

197

12 CFR 997.5 - Termination of the obligation.  

Code of Federal Regulations, 2010 CFR

...Treasury if the term of that obligation extends beyond April 15, 2030, will terminate when the aggregate actual quarterly payments...first obligation of the REFCORP was issued and ends on April 15, 2030. (b) Date of the final payment. The aggregate...

2010-01-01

198

7 CFR 1488.12 - Coverage of bank obligations.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

199

7 CFR 1488.12 - Coverage of bank obligations.  

Code of Federal Regulations, 2014 CFR

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

2014-01-01

200

7 CFR 1488.12 - Coverage of bank obligations.  

Code of Federal Regulations, 2012 CFR

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

2012-01-01

201

The Hidden Effect of Rules: Behavioural consequences of Obligations  

Microsoft Academic Search

How formal institutions (e.g. laws and public policies) affect human behaviour represents a crucial issue in economic analysis. Formal rules are defined as obligations backed by incentives. The economic literature has largely studied the role of material incentives in shaping individual behaviour. Yet, the role of obligations, i.e. what formal rules ask people to do or not to do, remains

Roberto Galbiati; Pietro Vertova

2006-01-01

202

Child Support Obligations and Low-Income Fathers  

ERIC Educational Resources Information Center

Using the 1994-1998 waves of the Current Population Survey--Child Support Supplement (N = 5,387), the aims of this study are to document child support obligation rates of nonresident fathers, to examine the effect of the obligation rate on child support compliance, and to calculate the trade-off between fathers' financial responsibility and…

Huang, Chien-Chung; Mincy, Ronald B.; Garfinkel, Irwin

2005-01-01

203

The Evolutionary Pathway to Obligate Scavenging in Gyps Vultures  

Microsoft Academic Search

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

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

2011-01-01

204

Schooling properties of an obligate and a facultative fish species  

E-print Network

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

Paris-Sud XI, Université de

205

The Role Obligations of Students and Lecturers in Higher Education  

ERIC Educational Resources Information Center

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

Regan, Julie-Anne

2012-01-01

206

Opportunism and competition in the non-fossil fuel obligation  

E-print Network

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

Watson, Andrew

207

Glutathione activates virulence gene expression of an intracellular pathogen.  

PubMed

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

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

2015-01-01

208

A common heritable factor influences prosocial obligations across multiple domains  

PubMed Central

Although it has been shown that prosocial behaviour is heritable, it has not yet been established whether narrower aspects of prosociality are heritable, nor whether a common mechanism influences prosociality across its multiple domains. Here, we examine civic duty, work-place commitment and concern for the welfare of others with a study of prosocial obligations in 958 adult twin-pairs. Multivariate modelling indicated the existence of genetic factors underlying general prosocial obligations in females, with familial effects (genetic and shared-environment effects were indistinguishable) influencing this general mechanism in males. At the domain-specific level, modest genetic effects were observed in females for civic and work obligations, with shared-environment effects influencing welfare obligations. In males, genetic influences were observed for welfare obligation, with unique environments affecting work and civic duty. PMID:21307044

Lewis, Gary J.; Bates, Timothy C.

2011-01-01

209

Comparative Genomics of Wolbachia and the Bacterial Species Concept  

PubMed Central

The importance of host-specialization to speciation processes in obligate host-associated bacteria is well known, as is also the ability of recombination to generate cohesion in bacterial populations. However, whether divergent strains of highly recombining intracellular bacteria, such as Wolbachia, can maintain their genetic distinctness when infecting the same host is not known. We first developed a protocol for the genome sequencing of uncultivable endosymbionts. Using this method, we have sequenced the complete genomes of the Wolbachia strains wHa and wNo, which occur as natural double infections in Drosophila simulans populations on the Seychelles and in New Caledonia. Taxonomically, wHa belong to supergroup A and wNo to supergroup B. A comparative genomics study including additional strains supported the supergroup classification scheme and revealed 24 and 33 group-specific genes, putatively involved in host-adaptation processes. Recombination frequencies were high for strains of the same supergroup despite different host-preference patterns, leading to genomic cohesion. The inferred recombination fragments for strains of different supergroups were of short sizes, and the genomes of the co-infecting Wolbachia strains wHa and wNo were not more similar to each other and did not share more genes than other A- and B-group strains that infect different hosts. We conclude that Wolbachia strains of supergroup A and B represent genetically distinct clades, and that strains of different supergroups can co-exist in the same arthropod host without converging into the same species. This suggests that the supergroups are irreversibly separated and that barriers other than host-specialization are able to maintain distinct clades in recombining endosymbiont populations. Acquiring a good knowledge of the barriers to genetic exchange in Wolbachia will advance our understanding of how endosymbiont communities are constructed from vertically and horizontally transmitted genes. PMID:23593012

Näslund, Kristina; Bourtzis, Kostas; Andersson, Siv G. E.

2013-01-01

210

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

Code of Federal Regulations, 2013 CFR

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

2013-10-01

211

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

Code of Federal Regulations, 2012 CFR

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

2012-10-01

212

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

Code of Federal Regulations, 2011 CFR

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

2011-10-01

213

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

Code of Federal Regulations, 2014 CFR

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

2014-10-01

214

31 CFR 225.9 - Return of Government obligations to obligor.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

215

31 CFR 225.9 - Return of Government obligations to obligor.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

216

31 CFR 225.9 - Return of Government obligations to obligor.  

Code of Federal Regulations, 2014 CFR

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

2014-07-01

217

31 CFR 225.9 - Return of Government obligations to obligor.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

218

31 CFR 225.9 - Return of Government obligations to obligor.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Return of Government obligations to obligor. 225... ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.9 Return of Government obligations to obligor....

2010-07-01

219

20 CFR 243.2 - Legal process for the enforcement of child support and alimony obligations.  

Code of Federal Regulations, 2010 CFR

...process for the enforcement of child support and alimony obligations. 243...process for the enforcement of child support and alimony obligations. ...of legal obligations to provide child support or to make alimony payments,...

2010-04-01

220

28 CFR 811.5 - Commencement of the obligation to register.  

Code of Federal Regulations, 2010 CFR

...false Commencement of the obligation to register. 811.5 Section 811.5 Judicial...5 Commencement of the obligation to register. (a) A sex offender's obligation to register starts when the sex offender is...

2010-07-01

221

47 CFR 1.21004 - Winning bidder's obligation to apply for support  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Winning bidder's obligation to apply for support ...Service Support § 1.21004 Winning bidder's obligation to apply for support ...and Sufficient Application. A winning bidder has a binding obligation to apply...

2013-10-01

222

47 CFR 1.21004 - Winning bidder's obligation to apply for support  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Winning bidder's obligation to apply for support ...Service Support § 1.21004 Winning bidder's obligation to apply for support ...and Sufficient Application. A winning bidder has a binding obligation to apply...

2012-10-01

223

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

PubMed Central

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

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

2014-01-01

224

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

PubMed

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

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

2014-05-01

225

Bacterial conjunctivitis  

PubMed Central

Introduction Most cases of conjunctivitis in adults are probably due to viral infection, but children are more likely to develop bacterial conjunctivitis than they are viral forms. The main bacterial pathogens are Haemophilus influenzae and Streptococcus pneumoniae in adults and children, and Moraxella catarrhalis in children. Contact lens wearers may be more likely to develop gram-negative infections. Bacterial keratitis occurs in up to 30 per 100,000 contact lens wearers. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of empirical treatment in adults and children with suspected bacterial conjunctivitis? What are the effects of treatment in adults and children with bacteriologically confirmed bacterial conjunctivitis? What are the effects of treatment in adults and children with clinically confirmed gonococcal conjunctivitis? We searched: Medline, Embase, The Cochrane Library, and other important databases up to July 2009 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 40 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: ocular decongestants; oral antibiotics; parenteral antibiotics; saline; topical antibiotics; and warm compresses. PMID:21718563

2010-01-01

226

Bacterial conjunctivitis  

PubMed Central

Introduction Most cases of conjunctivitis in adults are probably due to viral infection, but children are more likely to develop bacterial conjunctivitis than they are viral forms. The main bacterial pathogens are Haemophilus influenzae and Streptococcus pneumoniae in adults and children, and Moraxella catarrhalis in children. Contact lens wearers may be more likely to develop gram-negative infections. Bacterial keratitis occurs in up to 30 per 100,000 contact lens wearers. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of empirical treatment in adults and children with suspected bacterial conjunctivitis? What are the effects of treatment in adults and children with bacteriologically confirmed bacterial conjunctivitis? What are the effects of treatment in adults and children with clinically confirmed gonococcal conjunctivitis? We searched: Medline, Embase, The Cochrane Library, and other important databases up to July 2011 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 44 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: ocular decongestants, oral antibiotics, parenteral antibiotics, saline, topical antibiotics, and warm compresses. PMID:22348418

2012-01-01

227

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

PubMed

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

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

2011-04-01

228

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

Code of Federal Regulations, 2012 CFR

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

2012-01-01

229

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

Code of Federal Regulations, 2010 CFR

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

2010-01-01

230

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

Code of Federal Regulations, 2011 CFR

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

2011-01-01

231

Rickettsia as obligate and mycetomic bacteria.  

PubMed

Rickettsiae are well known as intracellular pathogens of animals, humans, and plants and facultative and unorganized symbionts of invertebrates. No close relative of mitochondria has yet been associated with nutritional or developmental dependency of its host cell or organism. We have found a mycetomic Rickettsia that is a strict obligatory symbiont of the parthenogenetic booklouse Liposcelis bostrychophila (Psocoptera). These rickettsiae show an evolutionary transition from a solitary to a primary mycetomic bacterium adapted to the development of its host. These intracellular and intranuclear bacteria reside in specialized cells in several tissues. Their distribution changes markedly with the development of their host. The most advanced phenotype is a paired mycetome in the abdomen, described for the first time for Rickettsia and this host order. The mycetomic rickettsiae of two parthenogenetic book lice species are in the spotted fever group and in the basal limoniae group. While mycetomic bacteria are well known for their metabolic or light-emitting functions, these rickettsiae have an essential role in the early development of the oocyte. Removal of the Rickettsia stops egg production and reproduction in the book louse. In two phylogenetically distant psocopteran species, Rickettsia are shown to be associated with four transitional stages from free bacteria, infected cells, through single mycetocytes to organ-forming mycetomes. PMID:17012243

Perotti, M Alejandra; Clarke, Heather K; Turner, Bryan D; Braig, Henk R

2006-11-01

232

Neurofilaments are obligate heteropolymers in vivo  

PubMed Central

Neurofilaments (NFs), composed of three distinct subunits NF-L, NF-M, and NF-H, are neuron-specific intermediate filaments present in most mature neurons. Using DNA transfection and mice expressing NF transgenes, we find that despite the ability of NF-L alone to assemble into short filaments in vitro NF-L cannot form filament arrays in vivo after expression either in cultured cells or in transgenic oligodendrocytes that otherwise do not contain a cytoplasmic intermediate filament (IF) array. Instead, NF-L aggregates into punctate or sheet like structures. Similar nonfilamentous structures are also formed when NF-M or NF-H is expressed alone. The competence of NF-L to assemble into filaments is fully restored by coexpression of NF- M or NF-H to a level approximately 10% of that of NF-L. Deletion of the head or tail domain of NF-M or substitution of the NF-H tail onto an NF- L subunit reveals that restoration of in vivo NF-L assembly competence requires an interaction provided by the NF-M or NF-H head domains. We conclude that, contrary to the expectation drawn from earlier in vitro assembly studies, NF-L is not sufficient to assemble an extended filament network in an in vivo context and that neurofilaments are obligate heteropolymers requiring NF-L and NF-M or NF-H. PMID:8376466

1993-01-01

233

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

PubMed Central

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

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

2013-01-01

234

26 CFR 1.163-4 - Deduction for original issue discount on certain obligations issued after May 27, 1969.  

Code of Federal Regulations, 2010 CFR

...certain obligations issued after May 27, 1969. 1.163-4 Section 1.163-4...certain obligations issued after May 27, 1969. (a) In general. ...respect of obligations issued after May 27, 1969, other than— (1) Obligations...

2010-04-01

235

Bacterial pathogenomics  

Microsoft Academic Search

Genomes from all of the crucial bacterial pathogens of humans, plants and animals have now been sequenced, as have genomes from many of the important commensal, symbiotic and environmental microorganisms. Analysis of these sequences has revealed the forces that shape pathogen evolution and has brought to light unexpected aspects of pathogen biology. The finding that horizontal gene transfer and genome

Mark J. Pallen; Brendan W. Wren

2007-01-01

236

Bacterial Biofertilizers  

Microsoft Academic Search

Many bacteria and fungi can enhance plant growth. The present review is limited to plant growth promoting rhizobacteria (PGPR). However, it includes endophytic bacteria that show plant growth enhancing activity as well. Also the best studied bacterial mechanisms of plant growth promotion are discussed, with a special emphasis on biological nitrogen fixation and synthesis of phytohormones, including less understood mechanisms

LUIS E. FUENTES-RAMIREZ; Jesus Caballero-Mellado

237

Bacterial concrete  

Microsoft Academic Search

Cracks in concrete are inevitable and are one of the inherent weaknesses of concrete. Water and other salts seep through these cracks, corrosion initiates, and thus reduces the life of concrete. So there was a need to develop an inherent biomaterial, a self-repairing material which can remediate the cracks and fissures in concrete. Bacterial concrete is a material, which can

Venkataswamy Ramakrishnan; K. P. Ramesh; S. S. Bang

2001-01-01

238

23 CFR 450.332 - Annual listing of obligated projects.  

Code of Federal Regulations, 2012 CFR

...OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.332 Annual listing of obligated projects. (a) In metropolitan planning areas, on an annual...

2012-04-01

239

23 CFR 450.332 - Annual listing of obligated projects.  

Code of Federal Regulations, 2014 CFR

...OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.332 Annual listing of obligated projects. (a) In metropolitan planning areas, on an annual...

2014-04-01

240

23 CFR 450.332 - Annual listing of obligated projects.  

Code of Federal Regulations, 2013 CFR

...OF TRANSPORTATION PLANNING AND RESEARCH PLANNING ASSISTANCE AND STANDARDS Metropolitan Transportation Planning and Programming § 450.332 Annual listing of obligated projects. (a) In metropolitan planning areas, on an annual...

2013-04-01

241

45 CFR 1226.13 - Obligations of sponsors.  

Code of Federal Regulations, 2010 CFR

... Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE PROHIBITIONS ON ELECTORAL AND LOBBYING ACTIVITIES Sponsor Employee Activities § 1226.13 Obligations of sponsors. (a) It shall be the...

2010-10-01

242

45 CFR 1226.13 - Obligations of sponsors.  

Code of Federal Regulations, 2011 CFR

... Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE PROHIBITIONS ON ELECTORAL AND LOBBYING ACTIVITIES Sponsor Employee Activities § 1226.13 Obligations of sponsors. (a) It shall be the...

2011-10-01

243

34 CFR 686.43 - Obligation to repay the grant.  

Code of Federal Regulations, 2014 CFR

...of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION (CONTINUED) TEACHER EDUCATION ASSISTANCE FOR COLLEGE AND HIGHER EDUCATION (TEACH) GRANT PROGRAM Service and Repayment Obligations § 686.43...

2014-07-01

244

34 CFR 686.40 - Documenting the service obligation.  

Code of Federal Regulations, 2014 CFR

...of Education (Continued) OFFICE OF POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION (CONTINUED) TEACHER EDUCATION ASSISTANCE FOR COLLEGE AND HIGHER EDUCATION (TEACH) GRANT PROGRAM Service and Repayment Obligations § 686.40...

2014-07-01

245

Obligation Policies: An Enforcement Platform Pedro Gama, Paulo Ferreira  

E-print Network

Obligation Policies: An Enforcement Platform Pedro Gama, Paulo Ferreira INESC-ID/IST Distributed Systems Group Rua Alves Redol, no 9, 1000-029 Lisboa [pedro.gama, paulo.ferreira]@gsd.inesc-id.pt Abstract

Ferreira, Paulo

246

29 CFR 500.100 - Vehicle safety obligations.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Vehicle safety obligations. 500.100 Section...AGRICULTURAL WORKER PROTECTION Motor Vehicle Safety and Insurance for Transportation...and Health for Migrant Workers Motor Vehicle Safety § 500.100 Vehicle...

2010-07-01

247

45 CFR 303.6 - Enforcement of support obligations.  

Code of Federal Regulations, 2010 CFR

...obligations. 303.6 Section 303.6 Public Welfare Regulations Relating to Public Welfare OFFICE OF CHILD SUPPORT ENFORCEMENT (CHILD SUPPORT ENFORCEMENT PROGRAM), ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN...

2010-10-01

248

47 CFR 25.701 - Public interest obligations.  

Code of Federal Regulations, 2013 CFR

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Public Interest Obligations...Entities licensed to operate satellites in the 12.2 to 12.7 GHz...

2013-10-01

249

47 CFR 25.701 - Public interest obligations.  

Code of Federal Regulations, 2011 CFR

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Public Interest Obligations...Entities licensed to operate satellites in the 12.2 to 12.7 GHz...

2011-10-01

250

47 CFR 25.701 - Public interest obligations.  

Code of Federal Regulations, 2012 CFR

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Public Interest Obligations...Entities licensed to operate satellites in the 12.2 to 12.7 GHz...

2012-10-01

251

7 CFR 760.507 - Obligations of a participant.  

Code of Federal Regulations, 2011 CFR

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

2011-01-01

252

7 CFR 760.507 - Obligations of a participant.  

Code of Federal Regulations, 2014 CFR

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

2014-01-01

253

7 CFR 1416.705 - Obligations of a participant.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

254

7 CFR 760.507 - Obligations of a participant.  

Code of Federal Regulations, 2012 CFR

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

2012-01-01

255

7 CFR 760.507 - Obligations of a participant.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

256

7 CFR 783.7 - Obligations of a participant.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

257

38 CFR 17.633 - Deferment of obligated service.  

Code of Federal Regulations, 2014 CFR

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

2014-07-01

258

29 CFR 5.31 - Meeting wage determination obligations.  

Code of Federal Regulations, 2014 CFR

...Interpretation of the Fringe Benefits Provisions of the Davis-Bacon Act § 5.31 Meeting wage determination obligations. ...contractor or subcontractor performing work subject to a Davis-Bacon wage determination may discharge his minimum wage...

2014-07-01

259

29 CFR 5.31 - Meeting wage determination obligations.  

Code of Federal Regulations, 2012 CFR

...Interpretation of the Fringe Benefits Provisions of the Davis-Bacon Act § 5.31 Meeting wage determination obligations. ...contractor or subcontractor performing work subject to a Davis-Bacon wage determination may discharge his minimum wage...

2012-07-01

260

29 CFR 5.31 - Meeting wage determination obligations.  

Code of Federal Regulations, 2011 CFR

...Interpretation of the Fringe Benefits Provisions of the Davis-Bacon Act § 5.31 Meeting wage determination obligations. ...contractor or subcontractor performing work subject to a Davis-Bacon wage determination may discharge his minimum wage...

2011-07-01

261

29 CFR 5.31 - Meeting wage determination obligations.  

Code of Federal Regulations, 2013 CFR

...Interpretation of the Fringe Benefits Provisions of the Davis-Bacon Act § 5.31 Meeting wage determination obligations. ...contractor or subcontractor performing work subject to a Davis-Bacon wage determination may discharge his minimum wage...

2013-07-01

262

29 CFR 5.31 - Meeting wage determination obligations.  

Code of Federal Regulations, 2010 CFR

...Interpretation of the Fringe Benefits Provisions of the Davis-Bacon Act § 5.31 Meeting wage determination obligations. ...contractor or subcontractor performing work subject to a Davis-Bacon wage determination may discharge his minimum wage...

2010-07-01

263

78 FR 49994 - Federal Management Regulation (FMR); Obligating Authority  

Federal Register 2010, 2011, 2012, 2013, 2014

...RIN 3090-AJ35 Federal Management Regulation (FMR); Obligating...proposing to amend the Federal Management Regulation (FMR) to recommend...Lee Gregory, Office of Asset and Transportation Management (MA), Office of...

2013-08-16

264

10 CFR 600.29 - Fixed obligation awards.  

Code of Federal Regulations, 2014 CFR

...subject to the following requirements: (1) Each fixed obligation award may neither exceed $250,000 nor exceed one year in length. (2) Programs which require mandatory cost sharing are not eligible. (3) Proposed costs must be...

2014-01-01

265

18 CFR 37.8 - Obligations of OASIS users.  

Code of Federal Regulations, 2010 CFR

...REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE FEDERAL POWER ACT OPEN ACCESS SAME-TIME INFORMATION SYSTEMS § 37.8 Obligations of OASIS users. Each OASIS user must notify the Responsible Party one month...

2010-04-01

266

7 CFR 984.54 - Establishment of obligation.  

Code of Federal Regulations, 2010 CFR

...Nuts), DEPARTMENT OF AGRICULTURE WALNUTS GROWN IN CALIFORNIA Order Regulating Handling Reserve Walnuts § 984.54 Establishment of obligation...kernelweight of certified merchantable walnuts equal to a quantity derived by the...

2010-01-01

267

47 CFR 25.701 - Public interest obligations.  

Code of Federal Regulations, 2014 CFR

... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Public Interest Obligations...Entities licensed to operate satellites in the 12.2 to 12.7 GHz...

2014-10-01

268

32 CFR 220.9 - Rights and obligations of beneficiaries.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

269

32 CFR 220.9 - Rights and obligations of beneficiaries.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

270

32 CFR 220.9 - Rights and obligations of beneficiaries.  

Code of Federal Regulations, 2014 CFR

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

2014-07-01

271

32 CFR 220.9 - Rights and obligations of beneficiaries.  

Code of Federal Regulations, 2010 CFR

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

2010-07-01

272

32 CFR 220.9 - Rights and obligations of beneficiaries.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

273

47 CFR 211.7 - Obligation of carriers.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Obligation of carriers. 211.7 Section 211.7 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EMERGENCY RESTORATION PRIORITY PROCEDURES FOR TELECOMMUNICATIONS SERVICES §...

2010-10-01

274

22 CFR 233.07 - Fiscal Agent obligations.  

Code of Federal Regulations, 2014 CFR

...obligations. 233.07 Section 233.07 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT HASHEMITE KINGDOM OF JORDAN LOAN GUARANTEES ISSUED UNDER THE FURTHER CONTINUING APPROPRIATIONS ACT, 2013, DIV. F, PUB. L. 113-6-STANDARD...

2014-04-01

275

INTRACELLULAR SIGNALING AND DEVELOPMENTAL NEUROTOXICITY.  

EPA Science Inventory

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

276

Autophagy and bacterial infectious diseases  

PubMed Central

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

Yuk, Jae-Min; Yoshimori, Tamotsu

2012-01-01

277

Intense Transpositional Activity of Insertion Sequences in an Ancient Obligate Endosymbiont  

PubMed Central

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

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

2008-01-01

278

Experimental selection of long-term intracellular mycobacteria  

PubMed Central

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

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

2014-01-01

279

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

Microsoft Academic Search

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

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

1995-01-01

280

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

Microsoft Academic Search

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

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

2009-01-01

281

Metallochaperones Regulate Intracellular Copper Levels  

PubMed Central

Copper (Cu) is an important enzyme co-factor that is also extremely toxic at high intracellular concentrations, making active efflux mechanisms essential for preventing Cu accumulation. Here, we have investigated the mechanistic role of metallochaperones in regulating Cu efflux. We have constructed a computational model of Cu trafficking and efflux based on systems analysis of the Cu stress response of Halobacterium salinarum. We have validated several model predictions via assays of transcriptional dynamics and intracellular Cu levels, discovering a completely novel function for metallochaperones. We demonstrate that in addition to trafficking Cu ions, metallochaperones also function as buffers to modulate the transcriptional responsiveness and efficacy of Cu efflux. This buffering function of metallochaperones ultimately sets the upper limit for intracellular Cu levels and provides a mechanistic explanation for previously observed Cu metallochaperone mutation phenotypes. PMID:23349626

Pang, W. Lee; Kaur, Amardeep; Ratushny, Alexander V.; Cvetkovic, Aleksandar; Kumar, Sunil; Pan, Min; Arkin, Adam P.; Aitchison, John D.; Adams, Michael W. W.; Baliga, Nitin S.

2013-01-01

282

Importance of branched-chain amino Acid utilization in francisella intracellular adaptation.  

PubMed

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

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

2015-01-01

283

Interleukin-10 and Immunity against Prokaryotic and Eukaryotic Intracellular Pathogens ?  

PubMed Central

The generation of an effective immune response against an infection while also limiting tissue damage requires a delicate balance between pro- and anti-inflammatory responses. Interleukin-10 (IL-10) has potent immunosuppressive effects and is essential for regulation of immune responses. However, the immunosuppressive properties of IL-10 can also be exploited by pathogens to facilitate their own survival. In this minireview, we discuss the role of IL-10 in modulating intracellular bacterial, fungal, and parasitic infections. Using information from several different infection models, we bring together and highlight some common pathways for IL-10 regulation and function that cannot be fully appreciated by studies of a single pathogen. PMID:21576331

Cyktor, Joshua C.; Turner, Joanne

2011-01-01

284

Intracellular Helicobacter pylori in gastric epithelial progenitors  

PubMed Central

Helicobacter pylori is generally viewed as an extracellular pathogen. We have analyzed the tropism of H. pylori clinical isolates in a gnotobiotic transgenic mouse model of human chronic atrophic gastritis, a preneoplastic condition. These mice lack acid-producing parietal cells and have an amplified population of dividing gastric epithelial progenitors (GEPs) that express NeuAc?2,3Gal?1,4-glycans recognized by H. pylori adhesins. Scanning confocal and transmission electron microscopic studies of stomachs that had been colonized for 1 month or 1 year revealed intracellular bacterial collections (IBCs) in a small subset of multi- and oligopotential epithelial progenitors. Transmission electron microscopic and multilabel immunohistochemical analyses disclosed bacteria with several morphotypes, including spiral-shaped, in the cytoplasm and endosomes. Several stages in IBC evolution were documented, from a few solitary bacteria to consolidated populations in dividing and nondividing GEPs, to microorganisms traversing breaches in the GEP plasma cell membrane. IBC formation was not a unique feature of H. pylori strains isolated from patients with chronic atrophic gastritis. The notion that adult mammalian epithelial progenitors can function as a repository for H. pylori broadens the view of host habitats available to this and perhaps other pathogens. PMID:15795379

Oh, Jung D.; Karam, Sherif M.; Gordon, Jeffrey I.

2005-01-01

285

Microsporidia Are Natural Intracellular Parasites of the Nematode Caenorhabditis elegans  

PubMed Central

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

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

2008-01-01

286

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

PubMed

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

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

2014-12-20

287

Cytochemical Differences in Bacterial Glycocalyx  

NASA Astrophysics Data System (ADS)

To examine new cytochemical aspects of the bacterial adhesion, a strain 41452/01 of the oral commensal Streptococcus sanguis and a wild strain of Staphylococcus aureus were grown with and without sucrose supplementation for 6 days. Osmiumtetraoxyde (OsO4), uranyl acetate (UA), ruthenium red (RR), cupromeronic blue (CB) staining with critical electrolytic concentrations (CECs), and the tannic acid-metal salt technique (TAMST) were applied for electron microscopy. Cytochemically, only RR-positive fimbriae in S. sanguis were visualized. By contrast, some types of fimbriae staining were observed in S. aureus glycocalyx: RR-positive, OsO4-positive, tannophilic and CB-positive with ceasing point at 0.3 M MgCl2. The CB staining with CEC, used for the first time for visualization of glycoproteins of bacterial glycocalyx, also reveals intacellular CB-positive substances-probably the monomeric molecules, that is, subunits forming the fimbriae via extracellular assembly. Thus, glycosylated components of the biofilm matrix can be reliably related to single cells. The visualization of intracellular components by CB with CEC enables clear distinction between S. aureus and other bacteria, which do not produce CB-positive substances. The small quantities of tannophilic substances found in S. aureus makes the use of TAMST for the same purpose difficult. The present work protocol enables, for the first time, a partial cytochemical differentiation of the bacterial glycocalyx.

Krautgartner, Wolf Dietrich; Vitkov, Ljubomir; Hannig, Matthias; Pelz, Klaus; Stoiber, Walter

2005-02-01

288

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

E-print Network

A microfluidic device for physical trapping and electrical lysis of bacterial cells Ning Bao that integrates the capture of bacterial cells using a microscale bead array and the rapid electrical lysis for release of intracellular materials. We study the retention of Escherichia coli cells with different

Lu, Chang

289

European air transport public service obligations: a periodic review  

Microsoft Academic Search

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

Aisling Reynolds-Feighan

1995-01-01

290

A test for obligate apomixis in grain sorghum R473  

Microsoft Academic Search

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

D. R. Marshall; R. W. Downes

1977-01-01

291

Changing Families, Changing Responsibilities: Family Obligations Following Divorce and Remarriage.  

ERIC Educational Resources Information Center

The high incidence of divorce and remarriage means that the structure of American families is changing. Drawing on 13 studies that explore intergenerational obligations, this book discusses the responsibilities of family members to one another after divorce and remarriage. Chapter 1, "Who Is Responsible for Dependent Family Members?," presents an…

Ganong, Lawrence H.; Coleman, Marilyn

292

7 CFR 930.163 - Deferment of restricted obligation.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

293

7 CFR 930.163 - Deferment of restricted obligation.  

Code of Federal Regulations, 2012 CFR

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

2012-01-01

294

7 CFR 930.163 - Deferment of restricted obligation.  

Code of Federal Regulations, 2011 CFR

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

2011-01-01

295

7 CFR 930.163 - Deferment of restricted obligation.  

Code of Federal Regulations, 2014 CFR

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

2014-01-01

296

7 CFR 930.163 - Deferment of restricted obligation.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

297

Mechanisms of Obligatory Intracellular Infection with Anaplasma phagocytophilum  

PubMed Central

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

Rikihisa, Yasuko

2011-01-01

298

INTRACELLULAR HEMOLYSIN OF PSEUDOMONAS AERUGINOSA  

PubMed Central

Berk, Richard S. (Wayne State University, Detroit, Mich.). Intracellular hemolysin of Pseudomonas aeruginosa. J. Bacteriol. 85:522–526. 1963.—Disruption of cells (2 to 6 days old) of Pseudomonas aeruginosa grown in Tryptose Broth devoid of blood yielded an intracellular hemolysin active on sheep and human erythrocytes. The intracellular agent was not usually detectable in cells grown under highly aerobic conditions. However, activity was observed after 48 hr of growth and appeared to reach a peak at 96 hr when grown under static conditions. Centrifugation of hemolytic extracts at 20,000 × g for 30 min resulted in a fractionation of activity into particulate and soluble components. Similar fractionation of activity occurred after adjustment of the pH of crude extracts to 1.40. In addition, hemolytic preparations were not inactivated by boiling for 90 min, by treatment with ethylenediaminetetraacetate, or by heating in equal volumes of 20% KOH. Activity over a wide pH range was noted, with a maximum occurring at approximately 6.0. However, some preparations occasionally exhibited a second peak on the alkaline side. PMID:14042927

Berk, Richard S.

1963-01-01

299

Bacterial Communities of Two Parthenogenetic Aphid Species Cocolonizing Two Host Plants across the Hawaiian Islands ?  

PubMed Central

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

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

2011-01-01

300

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

PubMed

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

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

2011-12-01

301

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

PubMed Central

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

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

2006-01-01

302

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

PubMed

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

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

2013-07-17

303

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

304

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

305

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

306

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

Code of Federal Regulations, 2014 CFR

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

2014-07-01

307

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

308

48 CFR 13.202 - Unenforceability of unauthorized obligations in micro-purchases.  

Code of Federal Regulations, 2013 CFR

...Unenforceability of unauthorized obligations in micro-purchases. 13.202 Section 13...ACQUISITION PROCEDURES Actions at or Below the Micro-Purchase Threshold 13.202 Unenforceability of unauthorized obligations in micro-purchases. Many...

2013-10-01

309

48 CFR 13.202 - Unenforceability of unauthorized obligations in micro-purchases.  

Code of Federal Regulations, 2014 CFR

...Unenforceability of unauthorized obligations in micro-purchases. 13.202 Section 13...ACQUISITION PROCEDURES Actions at or Below the Micro-Purchase Threshold 13.202 Unenforceability of unauthorized obligations in micro-purchases. Many...

2014-10-01

310

24 CFR 905.120 - Penalties for slow obligation or expenditure of Capital Fund program assistance.  

Code of Federal Regulations, 2011 CFR

...Penalties for slow obligation or expenditure of Capital Fund program assistance. 905.120 Section 905.120...AND URBAN DEVELOPMENT THE PUBLIC HOUSING CAPITAL FUND PROGRAM Capital Fund § 905.120 Penalties for slow obligation or...

2011-04-01

311

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

Code of Federal Regulations, 2010 CFR

28 Judicial Administration...to promote compliance with crime victims' rights obligations...to promote compliance with crime victims' rights obligations...protection of the rights of crime victims. See 18 U.S.C....

2010-07-01

312

45 CFR 402.26 - Time period for obligation and expenditure of grant funds.  

Code of Federal Regulations, 2014 CFR

...true Time period for obligation and expenditure of grant funds. 402.26 Section...CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES STATE LEGALIZATION...26 Time period for obligation and expenditure of grant funds. (a) Any...

2014-10-01

313

45 CFR 402.26 - Time period for obligation and expenditure of grant funds.  

Code of Federal Regulations, 2010 CFR

...false Time period for obligation and expenditure of grant funds. 402.26 Section...CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES STATE LEGALIZATION...26 Time period for obligation and expenditure of grant funds. (a) Any...

2010-10-01

314

45 CFR 402.26 - Time period for obligation and expenditure of grant funds.  

Code of Federal Regulations, 2012 CFR

...false Time period for obligation and expenditure of grant funds. 402.26 Section...CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES STATE LEGALIZATION...26 Time period for obligation and expenditure of grant funds. (a) Any...

2012-10-01

315

45 CFR 402.26 - Time period for obligation and expenditure of grant funds.  

Code of Federal Regulations, 2013 CFR

...true Time period for obligation and expenditure of grant funds. 402.26 Section...CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES STATE LEGALIZATION...26 Time period for obligation and expenditure of grant funds. (a) Any...

2013-10-01

316

45 CFR 402.26 - Time period for obligation and expenditure of grant funds.  

Code of Federal Regulations, 2011 CFR

...false Time period for obligation and expenditure of grant funds. 402.26 Section...CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES STATE LEGALIZATION...26 Time period for obligation and expenditure of grant funds. (a) Any...

2011-10-01

317

14 CFR 323.18 - Carriers' obligations when terminating, suspending, or reducing air service.  

Code of Federal Regulations, 2010 CFR

... Carriers' obligations when terminating, suspending, or reducing air service. 323.18 Section 323.18 Aeronautics and... Carriers' obligations when terminating, suspending, or reducing air service. Any air carrier that terminates,...

2010-01-01

318

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

Code of Federal Regulations, 2013 CFR

...the obligations may be transmitted by gift, bequest, or inheritance. (vi) A declaration that the election is made under...the obligation may be transmitted by gift, bequest, or inheritance. Therefore, all payments received to which the...

2013-04-01

319

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

Code of Federal Regulations, 2014 CFR

...the obligations may be transmitted by gift, bequest, or inheritance. (vi) A declaration that the election is made under...the obligation may be transmitted by gift, bequest, or inheritance. Therefore, all payments received to which the...

2014-04-01

320

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

Code of Federal Regulations, 2011 CFR

...the obligations may be transmitted by gift, bequest, or inheritance. (vi) A declaration that the election is made under...the obligation may be transmitted by gift, bequest, or inheritance. Therefore, all payments received to which the...

2011-04-01

321

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

Code of Federal Regulations, 2012 CFR

...the obligations may be transmitted by gift, bequest, or inheritance. (vi) A declaration that the election is made under...the obligation may be transmitted by gift, bequest, or inheritance. Therefore, all payments received to which the...

2012-04-01

322

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

Code of Federal Regulations, 2010 CFR

...the obligations may be transmitted by gift, bequest, or inheritance. (vi) A declaration that the election is made under...the obligation may be transmitted by gift, bequest, or inheritance. Therefore, all payments received to which the...

2010-04-01

323

40 CFR 80.1407 - How are the Renewable Volume Obligations calculated?  

Code of Federal Regulations, 2013 CFR

...following formulas: (1) Cellulosic biofuel. RVOCB,i = (RFStdCB,i ...Renewable Volume Obligation for cellulosic biofuel for an obligated party for calendar year...RFStdCB,i = The standard for cellulosic biofuel for calendar year i, determined by...

2013-07-01

324

40 CFR 80.1407 - How are the Renewable Volume Obligations calculated?  

Code of Federal Regulations, 2012 CFR

...following formulas: (1) Cellulosic biofuel. RVOCB,i = (RFStdCB,i ...Renewable Volume Obligation for cellulosic biofuel for an obligated party for calendar year...RFStdCB,i = The standard for cellulosic biofuel for calendar year i, determined by...

2012-07-01

325

40 CFR 80.1407 - How are the Renewable Volume Obligations calculated?  

Code of Federal Regulations, 2011 CFR

...following formulas: (1) Cellulosic biofuel. RVOCB,i = (RFStdCB,i ...Renewable Volume Obligation for cellulosic biofuel for an obligated party for calendar year...RFStdCB,i = The standard for cellulosic biofuel for calendar year i, determined by...

2011-07-01

326

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

Code of Federal Regulations, 2012 CFR

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

2012-10-01

327

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

Code of Federal Regulations, 2012 CFR

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

2012-10-01

328

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

Code of Federal Regulations, 2011 CFR

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

2011-10-01

329

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

Code of Federal Regulations, 2014 CFR

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

2014-10-01

330

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

Code of Federal Regulations, 2011 CFR

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

2011-10-01

331

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

Code of Federal Regulations, 2013 CFR

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

2013-10-01

332

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

Code of Federal Regulations, 2013 CFR

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

2013-10-01

333

78 FR 40953 - Loan Participations; Purchase, Sale and Pledge of Eligible Obligations; Purchase of Assets and...  

Federal Register 2010, 2011, 2012, 2013, 2014

...of Eligible Obligations; Purchase of Assets and Assumption...titled Loan Participations; Purchase, Sale and Pledge of Eligible Obligations; Purchase of Assets and Assumption...credit unions with additional time to prepare to comply...

2013-07-09

334

47 CFR 54.309 - Connect America Fund Phase II Public Interest Obligations.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 false Connect America Fund Phase II Public Interest Obligations. 54... § 54.309 Connect America Fund Phase II Public Interest Obligations. (a) A price cap carrier electing Phase II model-based support is...

2014-10-01

335

18 CFR 35.1 - Application; obligation to file rate schedules, tariffs and certain service agreements.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Application; obligation to file rate schedules, tariffs and certain service... § 35.1 Application; obligation to file rate schedules, tariffs and certain service... (a) Every public utility shall file with the Commission and...

2010-04-01

336

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

337

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

338

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

339

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

340

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

Code of Federal Regulations, 2014 CFR

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

2014-07-01

341

Reward Management Conference 2011 The role of perceived employer obligations in the interpretation of -and  

E-print Network

obligations. This leads to the consideration that employees systematically assess their total reward package. Keywords: psychological contract, total reward, affective commitment, meaning, expatriate hal-006751603rd Reward Management Conference 2011 1 The role of perceived employer obligations

Boyer, Edmond

342

40 CFR 152.97 - Rights and obligations of data submitters.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Rights and obligations of data submitters. 152.97 Section 152...PROCEDURES Procedures To Ensure Protection of Data Submitters' Rights § 152.97 Rights and obligations of data submitters. (a) Right to be...

2010-07-01

343

40 CFR 152.97 - Rights and obligations of data submitters.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Rights and obligations of data submitters. 152.97 Section 152...PROCEDURES Procedures To Ensure Protection of Data Submitters' Rights § 152.97 Rights and obligations of data submitters. (a) Right to be...

2012-07-01

344

40 CFR 152.97 - Rights and obligations of data submitters.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Rights and obligations of data submitters. 152.97 Section 152...PROCEDURES Procedures To Ensure Protection of Data Submitters' Rights § 152.97 Rights and obligations of data submitters. (a) Right to be...

2011-07-01

345

40 CFR 152.97 - Rights and obligations of data submitters.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Rights and obligations of data submitters. 152.97 Section 152...PROCEDURES Procedures To Ensure Protection of Data Submitters' Rights § 152.97 Rights and obligations of data submitters. (a) Right to be...

2013-07-01

346

42 CFR 64a.105 - What are the conditions of obligated service?  

Code of Federal Regulations, 2012 CFR

...105 Section 64a.105 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING OBLIGATED SERVICE FOR MENTAL HEALTH TRAINEESHIPS § 64a.105 What are the conditions of obligated...

2012-10-01

347

47 CFR 14.61 - Obligations with respect to internet browsers built into mobile phones.  

Code of Federal Regulations, 2013 CFR

... false Obligations with respect to internet browsers built into mobile phones...EQUIPMENT BY PEOPLE WITH DISABILITIES Internet Browsers Built Into Telephones Used With...14.61 Obligations with respect to internet browsers built into mobile phones....

2013-10-01

348

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

Code of Federal Regulations, 2010 CFR

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

2010-01-01

349

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

350

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

Code of Federal Regulations, 2014 CFR

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

2014-07-01

351

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

352

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

353

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

354

45 CFR 2553.83 - What financial obligation does the Corporation incur for non-Corporation funded projects?  

Code of Federal Regulations, 2010 CFR

... false What financial obligation does...non-Corporation funded projects? 2553.83...Non-Corporation Funded Projects § 2553.83 What financial obligation does...non-Corporation funded project does not create a financial obligation...

2010-10-01

355

45 CFR 2551.113 - What financial obligation does the Corporation incur for non-Corporation funded projects?  

Code of Federal Regulations, 2010 CFR

... false What financial obligation does...non-Corporation funded projects? 2551.113...Non-Corporation Funded SCP Projects § 2551.113 What financial obligation does...non-Corporation funded project, does not create a financial obligation...

2010-10-01

356

45 CFR 2552.113 - What financial obligation does the Corporation incur for non-Corporation funded projects?  

Code of Federal Regulations, 2010 CFR

... false What financial obligation does...non-Corporation funded projects? 2552.113...Grandparent Program Projects § 2552.113 What financial obligation does...non-Corporation funded project, does not create a financial obligation...

2010-10-01

357

26 CFR 1.163-5 - Denial of interest deduction on certain obligations issued after December 31, 1982, unless issued...  

Code of Federal Regulations, 2010 CFR

...foreign currency denominated obligation will not be treated as linked...dollar solely because the obligation is the subject of a swap transaction. (4 ) Distributor...person that offers or sells the obligation during the restricted...

2010-04-01

358

Invasive Extravillous Trophoblasts Restrict Intracellular Growth and Spread of Listeria monocytogenes  

PubMed Central

Listeria monocytogenes is a facultative intracellular bacterial pathogen that can infect the placenta, a chimeric organ made of maternal and fetal cells. Extravillous trophoblasts (EVT) are specialized fetal cells that invade the uterine implantation site, where they come into direct contact with maternal cells. We have shown previously that EVT are the preferred site of initial placental infection. In this report, we infected primary human EVT with L. monocytogenes. EVT eliminated ?80% of intracellular bacteria over 24-hours. Bacteria were unable to escape into the cytoplasm and remained confined to vacuolar compartments that became acidified and co-localized with LAMP1, consistent with bacterial degradation in lysosomes. In human placental organ cultures bacterial vacuolar escape rates differed between specific trophoblast subpopulations. The most invasive EVT—those that would be in direct contact with maternal cells in vivo—had lower escape rates than trophoblasts that were surrounded by fetal cells and tissues. Our results suggest that EVT present a bottleneck in the spread of L. monocytogenes from mother to fetus by inhibiting vacuolar escape, and thus intracellular bacterial growth. However, if L. monocytogenes is able to spread beyond EVT it can find a more hospitable environment. Our results elucidate a novel aspect of the maternal-fetal barrier. PMID:21408203

Zeldovich, Varvara B.; Robbins, Jennifer R.; Kapidzic, Mirhan; Lauer, Peter; Bakardjiev, Anna I.

2011-01-01

359

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

Code of Federal Regulations, 2014 CFR

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

2014-07-01

360

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

361

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

362

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

363

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

364

31 CFR 225.4 - Pledge of book-entry Government obligations.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Pledge of book-entry Government obligations. 225.4 Section 225...SERVICE ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.4 Pledge of book-entry Government obligations. (a)...

2012-07-01

365

31 CFR 225.4 - Pledge of book-entry Government obligations.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 false Pledge of book-entry Government obligations. 225.4 Section 225...SERVICE ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.4 Pledge of book-entry Government obligations. (a)...

2014-07-01

366

31 CFR 225.4 - Pledge of book-entry Government obligations.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Pledge of book-entry Government obligations. 225.4 Section 225...SERVICE ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.4 Pledge of book-entry Government obligations. (a)...

2011-07-01

367

31 CFR 225.4 - Pledge of book-entry Government obligations.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Pledge of book-entry Government obligations. 225.4 Section 225...SERVICE ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.4 Pledge of book-entry Government obligations. (a)...

2010-07-01

368

31 CFR 225.4 - Pledge of book-entry Government obligations.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Pledge of book-entry Government obligations. 225.4 Section 225...SERVICE ACCEPTANCE OF BONDS SECURED BY GOVERNMENT OBLIGATIONS IN LIEU OF BONDS WITH SURETIES § 225.4 Pledge of book-entry Government obligations. (a)...

2013-07-01

369

Bacterial concrete  

NASA Astrophysics Data System (ADS)

Cracks in concrete are inevitable and are one of the inherent weaknesses of concrete. Water and other salts seep through these cracks, corrosion initiates, and thus reduces the life of concrete. So there was a need to develop an inherent biomaterial, a self-repairing material which can remediate the cracks and fissures in concrete. Bacterial concrete is a material, which can successfully remediate cracks in concrete. This technique is highly desirable because the mineral precipitation induced as a result of microbial activities is pollution free and natural. As the cell wall of bacteria is anionic, metal accumulation (calcite) on the surface of the wall is substantial, thus the entire cell becomes crystalline and they eventually plug the pores and cracks in concrete. This paper discusses the plugging of artificially cracked cement mortar using Bacillus Pasteurii and Sporosarcina bacteria combined with sand as a filling material in artificially made cuts in cement mortar which was cured in urea and CaCl2 medium. The effect on the compressive strength and stiffness of the cement mortar cubes due to the mixing of bacteria is also discussed in this paper. It was found that use of bacteria improves the stiffness and compressive strength of concrete. Scanning electron microscope (SEM) is used to document the role of bacteria in microbiologically induced mineral precipitation. Rod like impressions were found on the face of calcite crystals indicating the presence of bacteria in those places. Energy- dispersive X-ray (EDX) spectra of the microbial precipitation on the surface of the crack indicated the abundance of calcium and the precipitation was inferred to be calcite (CaCO3).

Ramakrishnan, Venkataswamy; Ramesh, K. P.; Bang, S. S.

2001-04-01

370

INsPECT, an open-source and versatile software for automated quantification of (Leishmania) intracellular parasites.  

PubMed

Intracellular protozoan parasites are causative agents of infectious diseases that constitute major health problems for developing countries. Leishmania sp., Trypanosoma cruzi or Toxoplasma gondii are all obligate intracellular protozoan parasites that reside and multiply within the host cells of mammals, including humans. Following up intracellular parasite proliferation is therefore an essential and a quotidian task for many laboratories working on primary screening of new natural and synthetic drugs, analyzing drug susceptibility or comparing virulence properties of natural and genetically modified strains. Nevertheless, laborious manual microscopic counting of intracellular parasites is still the most commonly used approach. Here, we present INsPECT (Intracellular ParasitE CounTer), an open-source and platform independent software dedicated to automate infection level measurement based on fluorescent DNA staining. It offers the possibility to choose between different types of analyses (fluorescent DNA acquisitions only or in combination with phase contrast image set to further separate intra- from extracellular parasites), and software running modes (automatic or custom). A proof-of-concept study with intracellular Leishmania infantum parasites stained with DAPI (4',6-diamidino-2-phenylindole) confirms a good correspondence between digital results and the "gold standard" microscopic counting method with Giemsa. Interestingly, this software is versatile enough to accurately detect intracellular T. gondii parasites on images acquired with High Content Screening (HCS) systems. In conclusion, INsPECT software is proposed as a new fast and simple alternative to the classical intracellular Leishmania quantification methods and can be adapted for mid to large-scale drug screening against different intracellular parasites. PMID:24831235

Yazdanparast, Ehsan; Dos Anjos, Antonio; Garcia, Deborah; Loeuillet, Corinne; Shahbazkia, Hamid Reza; Vergnes, Baptiste

2014-05-01

371

INsPECT, an Open-Source and Versatile Software for Automated Quantification of (Leishmania) Intracellular Parasites  

PubMed Central

Intracellular protozoan parasites are causative agents of infectious diseases that constitute major health problems for developing countries. Leishmania sp., Trypanosoma cruzi or Toxoplasma gondii are all obligate intracellular protozoan parasites that reside and multiply within the host cells of mammals, including humans. Following up intracellular parasite proliferation is therefore an essential and a quotidian task for many laboratories working on primary screening of new natural and synthetic drugs, analyzing drug susceptibility or comparing virulence properties of natural and genetically modified strains. Nevertheless, laborious manual microscopic counting of intracellular parasites is still the most commonly used approach. Here, we present INsPECT (Intracellular ParasitE CounTer), an open-source and platform independent software dedicated to automate infection level measurement based on fluorescent DNA staining. It offers the possibility to choose between different types of analyses (fluorescent DNA acquisitions only or in combination with phase contrast image set to further separate intra- from extracellular parasites), and software running modes (automatic or custom). A proof-of-concept study with intracellular Leishmania infantum parasites stained with DAPI (4?,6-diamidino-2-phenylindole) confirms a good correspondence between digital results and the “gold standard” microscopic counting method with Giemsa. Interestingly, this software is versatile enough to accurately detect intracellular T. gondii parasites on images acquired with High Content Screening (HCS) systems. In conclusion, INsPECT software is proposed as a new fast and simple alternative to the classical intracellular Leishmania quantification methods and can be adapted for mid to large-scale drug screening against different intracellular parasites. PMID:24831235

Yazdanparast, Ehsan; Dos Anjos, Antonio; Garcia, Deborah; Loeuillet, Corinne; Shahbazkia, Hamid Reza; Vergnes, Baptiste

2014-01-01

372

Federal Academic Science and Engineering Obligations Increased More Than 12 Percent Between FY 1998 and FY 1999  

NSF Publications Database

Federal Academic Science and Engineering Obligations Increased More Than 12 Percent Between FY 1998 ... focuses on academic science and engineering obligations. Hypertext Format Portable Document Format ...

373

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

PubMed Central

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

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

2011-01-01

374

Antimycobacterial Efficacy of Andrographis paniculata Leaf Extracts Under Intracellular and Hypoxic Conditions.  

PubMed

The inhibition of the growth of Mycobacterium tuberculosis by the extracts of Andrographis paniculata has been studied using intracellular and axenic hypoxic conditions. The inhibition (confirmed using the gold standard colony forming unit assay) was found to increase with "double stimuli" or higher concentration of the extract. Organic solvent extracts were found to inhibit bacterial growth more than the aqueous extracts under microaerophilic conditions mimicked through axenic and intracellular assays. This could be further explored to evaluate the potential of the plant to be used against nonreplicating/dormant bacilli. PMID:25348959

Bhatter, Purva; Gupta, Pooja; Daswani, Poonam; Tetali, Pundarikakshudu; Birdi, Tannaz

2015-01-01

375

Intracellular ion channels and cancer  

PubMed Central

Several types of channels play a role in the maintenance of ion homeostasis in subcellular organelles including endoplasmatic reticulum, nucleus, lysosome, endosome, and mitochondria. Here we give a brief overview of the contribution of various mitochondrial and other organellar channels to cancer cell proliferation or death. Much attention is focused on channels involved in intracellular calcium signaling and on ion fluxes in the ATP-producing organelle mitochondria. Mitochondrial K+ channels (Ca2+-dependent BKCa and IKCa, ATP-dependent KATP, Kv1.3, two-pore TWIK-related Acid-Sensitive K+ channel-3 (TASK-3)), Ca2+ uniporter MCU, Mg2+-permeable Mrs2, anion channels (voltage-dependent chloride channel VDAC, intracellular chloride channel CLIC) and the Permeability Transition Pore (MPTP) contribute importantly to the regulation of function in this organelle. Since mitochondria play a central role in apoptosis, modulation of their ion channels by pharmacological means may lead to death of cancer cells. The nuclear potassium channel Kv10.1 and the nuclear chloride channel CLIC4 as well as the endoplasmatic reticulum (ER)-located inositol 1,4,5-trisphosphate (IP3) receptor, the ER-located Ca2+ depletion sensor STIM1 (stromal interaction molecule 1), a component of the store-operated Ca2+ channel and the ER-resident TRPM8 are also mentioned. Furthermore, pharmacological tools affecting organellar channels and modulating cancer cell survival are discussed. The channels described in this review are summarized on Figure 1. Overall, the view is emerging that intracellular ion channels may represent a promising target for cancer treatment. PMID:24027528

Leanza, Luigi; Biasutto, Lucia; Managò, Antonella; Gulbins, Erich; Zoratti, Mario; Szabò, Ildikò

2013-01-01

376

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

PubMed

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

Kaur, Sandeep; Harjai, Kusum; Chhibber, Sanjay

2014-05-01

377

Barcoding Hedgehog for Intracellular Transport  

NSDL National Science Digital Library

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

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

2011-11-22

378

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

PubMed Central

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

Manzano-Marín, Alejandro; Latorre, Amparo

2014-01-01

379

Floral scents repel facultative flower visitors, but attract obligate ones  

PubMed Central

Background and Aims Biological mutualisms rely on communication between partners, but also require protective measures against exploitation. Animal-pollinated flowers need to attract pollinators but also to avoid conflicts with antagonistic consumers. The view of flower visitors as mutualistic and antagonistic agents considers primarily the plants' interest. A classification emphasizing the consumer's point of view, however, may be more useful when considering animal's adaptations to flower visits which may include a tolerance against defensive floral scent compounds. Methods In a meta-analysis covering 18 studies on the responses of animals to floral scents, the animals were assigned to the categories of obligate and facultative flower visitors which considers their dependency on floral resources. Their responses on floral scents were compared. Key Results On average, obligate flower visitors, often corresponding to pollinators, were attracted to floral scent compounds. In contrast, facultative and mainly antagonistic visitors were strongly repelled by floral scents. The findings confirm that floral scents have a dual function both as attractive and defensive cues. Conclusions Whether an animal depends on floral resources determines its response to these signals, suggesting that obligate flower visitors evolved a tolerance against primarily defensive compounds. Therefore, floral scent bouquets in conjunction with nutritious rewards may solve the conflicting tasks of attracting mutualists while repelling antagonists. PMID:20228087

Junker, Robert R.; Blüthgen, Nico

2010-01-01

380

Spectra of intracellular Fura-2.  

PubMed

In the theory of measurement of calcium ion activity by determination of Fura-2 fluorescence at two excitation wavelengths, the accuracy of the result depends upon the accuracy both of the sample measurements and of the calibration measurements which are made on calcium-bound and free dye. Two factors underlie adequate calibration and accuracy. The first is the elimination of systematic error due to spectral shifts arising from the intracellular environment felt by the dye. To this end, detailed comparisons between complete spectra of both calcium-bound and calcium-free Fura-2 can be used to help separate spectral effects due to light absorption by cellular constituents versus polarity and viscosity of the intracellular milieu. The second major factor which determines accuracy is the experimental uncertainty (in both sample and calibration measurements). For samples in which the ratio of bound to free dye is large, the uncertainty in the ratio is also large, even when it is expressed as a percentage of the ratio itself. The errors in calibration measurements impact on the accuracy of the method primarily through the measurements made at wavelengths which are off the spectral peaks of the bound or free dye, since these are the least accurate. In order to obtain a guide to the choice of wavelengths and estimation of the reliability of results, a mathematical expression is derived for the dependence of the accuracy of the method on the accuracy of both sample and calibration measurements. PMID:1715814

Owen, C S

1991-06-01

381

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

PubMed Central

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

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

2012-01-01

382

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

PubMed Central

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

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

2013-01-01

383

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

PubMed Central

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

Muyzer, G.

2010-01-01

384

Carbon metabolism of intracellular bacteria.  

PubMed

Bacterial metabolism has been studied intensively since the first observations of these 'animalcules' by Leeuwenhoek and their isolation in pure cultures by Pasteur. Metabolic studies have traditionally focused on a small number of model organisms, primarily the Gram negative bacillus Escherichia coli, adapted to artificial culture conditions in the laboratory. Comparatively little is known about the physiology and metabolism of wild microorganisms living in their natural habitats. For approximately 500-1000 species of commensals and symbionts, and a smaller number of pathogenic bacteria, that habitat is the human body. Emerging evidence suggests that the metabolism of bacteria grown in vivo differs profoundly from their metabolism in axenic cultures. PMID:16367862

Muñoz-Elías, Ernesto J; McKinney, John D

2006-01-01

385

Bacterial Skin Infections  

MedlinePLUS

... Disorders Pigment Disorders Blistering Diseases Parasitic Skin Infections Bacterial Skin Infections Fungal Skin Infections Viral Skin Infections Sunlight and Skin Damage Noncancerous Skin Growths Skin Cancers Nail Disorders Topics in Bacterial Skin ...

386

Bacterial Gene Transfer  

NSDL National Science Digital Library

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

Roberta Ellington (Northwestern University; )

1991-01-01

387

The Iron Efflux Protein Ferroportin Regulates the Intracellular Growth of Salmonella enterica  

Microsoft Academic Search

Received 7 December 2005\\/Returned for modification 31 January 2006\\/Accepted 15 February 2006 We investigated the influence of the macrophage iron exporter ferroportin and its ligand hepcidin on intracellular Salmonella growth. Elevated ferroportin expression inhibited bacterial multiplication; hepcidin- induced ferroportin down-regulation enhanced it. Expression analysis of iron-responsive Salmonella genes indicated ferroportin-mediated iron deprivation. These results demonstrate a role for ferroportin in

Sabine Chlosta; Douglas S. Fishman; Lynne Harrington; Erin E. Johnson; Mitchell D. Knutson; Marianne Wessling-Resnick; Bobby J. Cherayil

2006-01-01

388

Maintenance of Vacuole Integrity by Bacterial Pathogens  

PubMed Central

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

Creasey, Elizabeth A.; Isberg, Ralph R.

2014-01-01

389

Intracellular sensing of complement C3 activates cell autonomous immunity.  

PubMed

Pathogens traverse multiple barriers during infection, including cell membranes. We found that during this transition, pathogens carried covalently attached complement C3 into the cell, triggering immediate signaling and effector responses. Sensing of C3 in the cytosol activated mitochondrial antiviral signaling (MAVS)-dependent signaling cascades and induced proinflammatory cytokine secretion. C3 also flagged viruses for rapid proteasomal degradation, preventing their replication. This system could detect both viral and bacterial pathogens but was antagonized by enteroviruses, such as rhinovirus and poliovirus, which cleave C3 using their 3C protease. The antiviral rupintrivir inhibited 3C protease and prevented C3 cleavage, rendering enteroviruses susceptible to intracellular complement sensing. Thus, complement C3 allows cells to detect and disable pathogens that have invaded the cytosol. PMID:25190799

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

2014-09-01

390

Bacterial moonlighting proteins and bacterial virulence.  

PubMed

Implicit in the central dogma is the hypothesis that each protein gene product has but one function. However, over the past decade, it has become clear that many proteins have one or more unique functions, over-and-above the principal biological action of the specific protein. This phenomenon is now known as protein moonlighting and many well-known proteins such as metabolic enzymes and molecular chaperones are now recognised as moonlighting proteins. A growing number of bacterial species are being found to have moonlighting proteins and the moonlighting activities of such proteins can contribute to bacterial virulence behaviour. The glycolytic enzymes, glyceraldehyde-3-phosphate dehydrogenase (GAPD) and enolase, and the cell stress proteins: chaperonin 60, Hsp70 and peptidyl prolyl isomerase, are among the most common of the bacterial moonlighting proteins which play a role in bacterial virulence. Moonlighting activities include adhesion and modulation of cell signalling processes. It is likely that only the tip of the bacterial moonlighting iceberg has been sighted and the next decade will bring with it many new discoveries of bacterial moonlighting proteins with a role in bacterial virulence. PMID:22143554

Henderson, Brian; Martin, Andrew

2013-01-01

391

Invasion and Intracellular Survival of Burkholderia cepacia  

PubMed Central

Burkholderia cepacia has emerged as an important pulmonary pathogen in immunocompromised patients and in patients with cystic fibrosis (CF). Little is known about the virulence factors and pathogenesis of B. cepacia, although the persistent and sometimes invasive infections caused by B. cepacia suggest that the organism possesses mechanisms for both cellular invasion and evasion of the host immune response. In this study, cultured human cells were used to analyze the invasion and intracellular survival of B. cepacia J2315, a highly transmissible clinical isolate responsible for morbidity and mortality in CF patients. Quantitative invasion and intracellular growth assays demonstrated that B. cepacia J2315 was able to enter, survive, and replicate intracellularly in U937-derived macrophages and A549 pulmonary epithelial cells. Transmission electron microscopy of infected macrophages confirmed the presence of intracellular B. cepacia and showed that intracellular bacteria were contained within membrane-bound vacuoles. An environmental isolate of B. cepacia, strain J2540, was also examined for its ability to invade and survive intracellularly in cultured human cells. J2540 entered cultured macrophages with an invasion frequency similar to that of the clinical strain, but it was less invasive than the clinical strain in epithelial cells. In marked contrast to the clinical strain, the environmental isolate was unable to survive or replicate intracellularly in either cultured macrophages or epithelial cells. Invasion and intracellular survival may play important roles in the ability of virulent strains of B. cepacia to evade the host immune response and cause persistent infections in CF patients. PMID:10603364

Martin, Daniel W.; Mohr, Christian D.

2000-01-01

392

Flavobacteria as Intracellular Symbionts in Cockroaches  

Microsoft Academic Search

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

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

1994-01-01

393

Intracellular Signaling by the Unfolded Protein  

E-print Network

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

Mullins, Dyche

394

[Pulmonary mycobacterium intracellulare infection complicated with pneumothorax and chronic empyema].  

PubMed

A 75-year-old woman who had been treated for pulmonary Mycobacterium intracellulare infection was admitted to a nearby hospital because of hemoptysis, right pneumothorax, and empyema. She had been treated by thoracic drainage and pleural lavage, but was reffered to our hospital because of refractory empyema. Her chest radiograph and chest computed tomography( CT) showed right chronic empyema of which pleural aspirate was smear positive for acid-fast bacilli and positive for the polymerase chain reaction method(PCR)-Mycobacterium intracellulare. Serum levels of white blood cell and C-reactive protein(CRP) were found to be slightly elevated. She was treated with combined use of ethambutol, rifampicin, clarithromycin, and kanamycin and with pleural curettage by thoracoscopic surgery. After surgery additional treatment was done using urokinase which was administered into the thoracic cavity via an thoracic tube. Chronic empyema gradually improved with the treatment and the pleural effusion became bacterial free, enabling the patient to discharge from hospital without thoracic drainage. PMID:23917230

Yamamoto, Jun; Shimanouchi, Masaoki; Ueda, Yoshiaki; Hashizume, Toshinori; Suito, Tetsushi

2013-08-01

395

Calcium efflux is essential for bacterial survival in the eukaryotic host  

PubMed Central

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

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

2008-01-01

396

Diagnostic Accuracy of Intracellular Mycobacterium tuberculosis Detection for Tuberculous Meningitis  

PubMed Central

Rationale: Early diagnosis and treatment of tuberculous meningitis saves lives, but current laboratory diagnostic tests lack sensitivity. Objectives: We investigated whether the detection of intracellular bacteria by a modified Ziehl-Neelsen stain and early secretory antigen target (ESAT)-6 in cerebrospinal fluid leukocytes improves tuberculous meningitis diagnosis. Methods: Cerebrospinal fluid specimens from patients with suspected tuberculous meningitis were stained by conventional Ziehl-Neelsen stain, a modified Ziehl-Neelsen stain involving cytospin slides with Triton processing, and an ESAT-6 immunocytochemical stain. Acid-fast bacteria and ESAT-6–expressing leukocytes were detected by microscopy. All tests were performed prospectively in a central laboratory by experienced technicians masked to the patients’ final diagnosis. Measurements and Main Results: Two hundred and eighty patients with suspected tuberculous meningitis were enrolled. Thirty-seven had Mycobacterium tuberculosis cultured from cerebrospinal fluid; 40 had a microbiologically confirmed alternative diagnosis; the rest had probable or possible tuberculous meningitis according to published criteria. Against a clinical diagnostic gold standard the sensitivity of conventional Ziehl-Neelsen stain was 3.3% (95% confidence interval, 1.6–6.7%), compared with 82.9% (95% confidence interval, 77.4–87.3%) for modified Ziehl-Neelsen stain and 75.1% (95% confidence interval, 68.8–80.6%) for ESAT-6 immunostain. Intracellular bacteria were seen in 87.8% of the slides positive by the modified Ziehl-Neelsen stain. The specificity of modified Ziehl-Neelsen and ESAT-6 stain was 85.0% (95% confidence interval, 69.4–93.8%) and 90.0% (95% confidence interval, 75.4–96.7%), respectively. Conclusions: Enhanced bacterial detection by simple modification of the Ziehl-Neelsen stain and an ESAT-6 intracellular stain improve the laboratory diagnosis of tuberculous meningitis. PMID:24450377

Feng, Guo-dong; Shi, Ming; Ma, Lei; Chen, Ping; Wang, Bing-ju; Zhang, Min; Chang, Xiao-lin; Su, Xiu-chu; Yang, Yi-ning; Fan, Xin-hong; Dai, Wen; Liu, Ting-ting; He, Ying; Bian, Ting; Duan, Li-xin; Li, Jin-ge; Hao, Xiao-ke; Liu, Jia-yun; Xue, Xin; Song, Yun-zhang; Wu, Hai-qin; Niu, Guo-qiang; Zhang, Li; Han, Cui-juan; Lin, Hong; Lin, Zhi-hui; Liu, Jian-jun; Jian, Qian; Zhang, Jin-she; Tian, Ye; Zhou, Bai-yu; Wang, Jing; Xue, Chang-hu; Han, Xiao-fang; Wang, Jian-feng; Wang, Shou-lian

2014-01-01

397

Cell Extract-Containing Medium for Culture of Intracellular Fastidious Bacteria  

PubMed Central

The culture of fastidious microorganisms is a critical step in infectious disease studies. As a proof-of-concept experiment, we evaluated an empirical medium containing eukaryotic cell extracts for its ability to support the growth of Coxiella burnetii. Here, we demonstrate the exponential growth of several bacterial strains, including the C. burnetii Nine Mile phase I and phase II strains, and C. burnetii isolates from humans and animals. Low-oxygen-tension conditions and the presence of small hydrophilic molecules and short peptides were critical for facilitating growth. Moreover, bacterial antigenicity was conserved, revealing the potential for this culture medium to be used in diagnostic tests and in the elaboration of vaccines against C. burnetii. We were also able to grow the majority of previously tested intracellular and fastidious bacterial species, including Tropheryma whipplei, Mycobacterium bovis, Leptospira spp., Borrelia spp., and most putative bioterrorism agents. However, we were unable to culture Rickettsia africae and Legionella spp. in this medium. The versatility of this medium should encourage its use as a replacement for the cell-based culture systems currently used for growing several facultative and putative intracellular bacterial species. PMID:23740722

Singh, Sudhir; Kowalczewska, Malgorzata; Edouard, Sophie; Eldin, Carole; Perreal, Céline; Weber, Pascal; Azza, Said

2013-01-01

398

Oscillations in intracellular signaling cascades  

NASA Astrophysics Data System (ADS)

In this paper, we study the oscillatory dynamics of intracellular signaling cascades. We derive a reaction-diffusion model of the mitogen-activated protein kinase cascade, and use it to show how oscillations of the protein kinase concentrations can occur as a function of the depth of the cascade. We find that only cascades with depths of three or more layers undergo oscillatory instabilities. In addition, the oscillatory instability is spatially uniform. Thus, the oscillations synchronize the protein kinase concentrations and result in them being uniformly distributed in the cytosol, despite the presence of protein kinase diffusion. Finally, we show how the oscillations are perturbed when parallel cascades “crosstalk.” We find that the protein kinases in the downstream layers of the cascade are less perturbed than those in the upstream layers. In particular, cascades of three layers are able to maintain the total power of the protein kinase activities at approximately the unperturbed level. Taken together, our results suggest that only cascades of at least three layers can synchronize the oscillations of protein kinases in the cytosol and operate in parallel in the presence of crosstalk without loss of signaling fidelity.

Chiam, K.-H.; Rajagopal, Gunaretnam

2007-06-01

399

The Evolutionary Pathway to Obligate Scavenging in Gyps Vultures  

PubMed Central

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

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

2011-01-01

400

47 CFR 54.802 - Obligations of local exchange carriers and the Administrator.  

Code of Federal Regulations, 2010 CFR

...COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Interstate Access Universal Service Support Mechanism § 54.802 Obligations of local exchange carriers and the Administrator. (a) Each Eligible...

2010-10-01

401

25 CFR 163.42 - Obligated service and breach of contract.  

Code of Federal Regulations, 2014 CFR

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

2014-04-01

402

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

PubMed Central

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

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

2013-01-01

403

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

PubMed

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

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

2015-02-15

404

Manganese (Mn) oxidation increases intracellular Mn in Pseudomonas putida GB-1.  

PubMed

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

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

2013-01-01

405

Stochastic resonance in an intracellular genetic perceptron.  

PubMed

Intracellular genetic networks are more intelligent than was first assumed due to their ability to learn. One of the manifestations of this intelligence is the ability to learn associations of two stimuli within gene-regulating circuitry: Hebbian-type learning within the cellular life. However, gene expression is an intrinsically noisy process; hence, we investigate the effect of intrinsic and extrinsic noise on this kind of intracellular intelligence. We report a stochastic resonance in an intracellular associative genetic perceptron, a noise-induced phenomenon, which manifests itself in noise-induced increase of response in efficiency after the learning event under the conditions of optimal stochasticity. PMID:24730883

Bates, Russell; Blyuss, Oleg; Zaikin, Alexey

2014-03-01

406

Association of ActA to Peptidoglycan Revealed by Cell Wall Proteomics of Intracellular Listeria monocytogenes*  

PubMed Central

Listeria monocytogenes is a Gram-positive intracellular bacterial pathogen that colonizes the cytosol of eukaryotic cells. Recent transcriptomic studies have revealed that intracellular L. monocytogenes alter expression of genes encoding envelope components. However, no comparative global analysis of this cell wall remodeling process is yet known at the protein level. Here, we used high resolution mass spectrometry to define the cell wall proteome of L. monocytogenes growing inside epithelial cells. When compared with extracellular bacteria growing in a nutrient-rich medium, a major difference found in the proteome was the presence of the actin assembly-inducing protein ActA in peptidoglycan purified from intracellular bacteria. ActA was also identified in the peptidoglycan of extracellular bacteria growing in a chemically defined minimal medium. In this condition, ActA maintains its membrane anchoring domain and promotes efficient bacterial entry into nonphagocytic host cells. Unexpectedly, Internalin-A, which mediates entry of extracellular L. monocytogenes into eukaryotic cells, was identified at late infection times (6 h) as an abundant protein in the cell wall of intracellular bacteria. Other surface proteins covalently bound to the peptidoglycan, as Lmo0514 and Lmo2085, were detected exclusively in intracellular and extracellular bacteria, respectively. Altogether, these data provide the first insights into the changes occurring at the protein level in the L. monocytogenes cell wall as the pathogen transits from the extracellular environment to an intracytosolic lifestyle inside eukaryotic cells. Some of these changes include alterations in the relative amount and the mode of association of certain surface proteins. PMID:21846725

García-del Portillo, Francisco; Calvo, Enrique; D'Orazio, Valentina; Pucciarelli, M. Graciela

2011-01-01

407

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

PubMed

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

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

2014-12-01

408

Nanoparticles for intracellular-targeted drug delivery  

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

409

Comparative Phylogeography in a Specific and Obligate Pollination Antagonism  

PubMed Central

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

Espíndola, Anahí; Alvarez, Nadir

2011-01-01

410

INTRACELLULAR OXIDATION-REDUCTION STUDIES  

PubMed Central

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

Cohen, Barnett; Chambers, Robert; Reznikoff, Paul

1928-01-01

411

Molecular Mechanisms Controlling GLUT4 Intracellular Retention  

Microsoft Academic Search

ABSTRACT In basal adipocytes GLUT4 is sequestered intracellularly by an insulin-reversible retention mechanism. Here we analyze the roles of three GLUT4 trafficking motifs (FQQI, TELEY and LL), providing molecular links between insulin signaling, cellular trafficking machinery and the motifs in the specialized trafficking of GLUT4. Our resultssupport a GLUT4 retention model that involves two linked intracellular cycles: one between endosomes

Vincent Blot; Timothy E. McGraw

2008-01-01

412

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

Microsoft Academic Search

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

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

2008-01-01

413

Hospital/Health Facilities and the Hill-Burton Obligations: A Secret from the Black Community.  

ERIC Educational Resources Information Center

Uncompensated/free care and community service obligations under the Hill-Burton Act can assist substantially in providing needed health care services to the Black community. Blacks, however, must become knowledgeable about these obligations, develop monitoring projects, and be prepared to take legal steps to bring Hill-Burton facilities into…

Rice, Mitchell F.

1986-01-01

414

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

ERIC Educational Resources Information Center

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

Coutrier, Karen A.

2011-01-01

415

45 CFR 96.14 - Time period for obligation and expenditure of grant funds.  

Code of Federal Regulations, 2014 CFR

...period for obligation and expenditure of grant funds. 96...Welfare Department of Health and Human Services...period for obligation and expenditure of grant funds. ...exist on the time for expenditure of block grant funds...maternal and child health services, and...

2014-10-01

416

45 CFR 96.14 - Time period for obligation and expenditure of grant funds.  

Code of Federal Regulations, 2011 CFR

...period for obligation and expenditure of grant funds. 96...Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES...period for obligation and expenditure of grant funds. ...exist on the time for expenditure of block grant funds...maternal and child health services, and...

2011-10-01

417

45 CFR 96.14 - Time period for obligation and expenditure of grant funds.  

Code of Federal Regulations, 2010 CFR

...period for obligation and expenditure of grant funds. 96...Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES...period for obligation and expenditure of grant funds. ...exist on the time for expenditure of block grant funds...maternal and child health services, and...

2010-10-01

418

45 CFR 96.14 - Time period for obligation and expenditure of grant funds.  

Code of Federal Regulations, 2012 CFR

...period for obligation and expenditure of grant funds. 96...Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES...period for obligation and expenditure of grant funds. ...exist on the time for expenditure of block grant funds...maternal and child health services, and...

2012-10-01

419

45 CFR 96.14 - Time period for obligation and expenditure of grant funds.  

Code of Federal Regulations, 2013 CFR

...period for obligation and expenditure of grant funds. 96...Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES...period for obligation and expenditure of grant funds. ...exist on the time for expenditure of block grant funds...maternal and child health services, and...

2013-10-01

420

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

Code of Federal Regulations, 2014 CFR

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

2014-04-01

421

28 CFR 811.6 - Duration of the obligation to register.  

Code of Federal Regulations, 2010 CFR

...false Duration of the obligation to register. 811.6 Section 811.6 Judicial...811.6 Duration of the obligation to register. (a) Lifetime registration. ...for a sex offender who is required to register for life shall end upon the sex...

2010-07-01

422

Contractual obligations and the sharing of confidential health information in sport  

Microsoft Academic Search

As an employee, a sports doctor has obligations to their employer, but also professional and widely accepted obligations of a doctor to the patient (in this case the individual team member). The conflict is evident when sports doctors are asked by an athlete to keep personal health information confidential from the coach and team management, and yet both doctor and

L Anderson

2008-01-01

423

17 CFR 290.3 - Reports with respect to proposed distribution of obligations.  

Code of Federal Regulations, 2010 CFR

The EBRD shall file with the Commission, on or prior to the date on which it sells any of its primary obligations in connection with a distribution of such obligations in the United States, a report containing the information and documents specified in Schedule A of this...

2010-04-01

424

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

ERIC Educational Resources Information Center

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

Edwards, Jan

2006-01-01

425

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

426

John Locke on Obligation: Sensation, Reflection, and the Natural Duty to Consent  

Microsoft Academic Search

DISSERTATION ABSTRACT: John Locke on Obligation: Sensation, Reflection, and the Natural Duty to Consent By Emily Marie Crookston Doctor of Philosophy in Philosophy Washington University in St. Louis, 2009 Professor Larry May, Chairperson Locke's theories of moral and political obligation are instructive both in their successes and in their failures. Writing during a time in which previous assumptions were being

Emily Crookston

2009-01-01

427

Parabacteroides chartae sp. nov., an obligately anaerobic species from wastewater of a paper mill.  

PubMed

A bacterial strain, designated NS31-3(T), was isolated from the wastewater of a paper mill. Cells of the isolate were obligately anaerobic, non-pigmented, non-motile, Gram-negative, short rods (0.7-1.0 × 1.4-2.5 µm). The isolate was able to grow on media containing 20% bile salts. API 20A tests showed that acid was produced from glucose, lactose, sucrose, maltose, D-xylose, L-arabinose, cellobiose, D-mannose, D-melezitose, D-raffinose, D-trehalose, D-mannitol, salicin and D-sorbitol. The main fermentation products from PYG broth were lactic acid, propionic acid, formic acid and acetic acid. Chemotaxonomic analysis showed that the major fatty acids were anteiso-C(15:0), C(15:0) and iso-C(17:0) 3-OH and the predominant respiratory quinones were MK-9 and MK-10. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain NS31-3(T) was related to members of genus Parabacteroides (91.2-93.2% sequence similarity); the isolate had the closest affinity with Parabacteroides merdae JCM 9497(T). The G+C content of the genomic DNA was 37.2 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic analysis, strain NS31-3(T) represents a novel species of the genus Parabacteroides, for which the name Parabacteroides chartae sp. nov. is proposed. The type strain is NS31-3(T) (=JCM 17797(T) =DSM 24967(T)). PMID:22199215

Tan, Hai-Qin; Li, Tian-Tian; Zhu, Chu; Zhang, Xin-Qi; Wu, Min; Zhu, Xu-Fen

2012-11-01

428

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

PubMed

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

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

2014-09-26

429

Bacterial Community Affects Toxin Production by Gymnodinium catenatum  

PubMed Central

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

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

2014-01-01

430

An Extended Role-Based Access Control Model for Delegating Obligations  

NASA Astrophysics Data System (ADS)

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

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

431

Observer perceptions of moral obligations in groups with a history of victimization.  

PubMed

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. PMID:22427385

Warner, Ruth H; Branscombe, Nyla R

2012-07-01

432

7, 787822, 2010 Increased bacterial  

E-print Network

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

Poggiale, Jean-Christophe

433

34 CFR 611.45 - Under what circumstances does the Secretary discharge a scholarship recipient's obligation to...  

Code of Federal Regulations, 2013 CFR

...does the Secretary discharge a scholarship recipient's obligation to repay...QUALITY ENHANCEMENT GRANTS PROGRAM Scholarships § 611.45 Under what circumstances...does the Secretary discharge a scholarship recipient's obligation to...

2013-07-01

434

34 CFR 611.45 - Under what circumstances does the Secretary discharge a scholarship recipient's obligation to...  

Code of Federal Regulations, 2011 CFR

...does the Secretary discharge a scholarship recipient's obligation to repay...QUALITY ENHANCEMENT GRANTS PROGRAM Scholarships § 611.45 Under what circumstances...does the Secretary discharge a scholarship recipient's obligation to...

2011-07-01

435

34 CFR 611.45 - Under what circumstances does the Secretary discharge a scholarship recipient's obligation to...  

Code of Federal Regulations, 2010 CFR

...does the Secretary discharge a scholarship recipient's obligation to repay...QUALITY ENHANCEMENT GRANTS PROGRAM Scholarships § 611.45 Under what circumstances...does the Secretary discharge a scholarship recipient's obligation to...

2010-07-01

436

34 CFR 611.45 - Under what circumstances does the Secretary discharge a scholarship recipient's obligation to...  

Code of Federal Regulations, 2014 CFR

...does the Secretary discharge a scholarship recipient's obligation to repay...QUALITY ENHANCEMENT GRANTS PROGRAM Scholarships § 611.45 Under what circumstances...does the Secretary discharge a scholarship recipient's obligation to...

2014-07-01

437

34 CFR 611.45 - Under what circumstances does the Secretary discharge a scholarship recipient's obligation to...  

Code of Federal Regulations, 2012 CFR

...does the Secretary discharge a scholarship recipient's obligation to repay...QUALITY ENHANCEMENT GRANTS PROGRAM Scholarships § 611.45 Under what circumstances...does the Secretary discharge a scholarship recipient's obligation to...

2012-07-01

438

17 CFR 255.16 - Ownership of interests in and sponsorship of issuers of certain collateralized debt obligations...  

Code of Federal Regulations, 2014 CFR

...debt obligations backed by trust-preferred securities. 255.16 Section...debt obligations backed by trust-preferred securities. (a) The prohibition...Collateral shall mean any trust preferred security or subordinated...

2014-04-01

439

17 CFR 75.16 - Ownership of interests in and sponsorship of issuers of certain collateralized debt obligations...  

Code of Federal Regulations, 2014 CFR

...debt obligations backed by trust-preferred securities. 75.16 Section 75...debt obligations backed by trust-preferred securities. (a) The prohibition...Collateral shall mean any trust preferred security or subordinated...

2014-04-01

440

5 CFR 2422.34 - What are the parties' rights and obligations when a representation proceeding is pending?  

Code of Federal Regulations, 2013 CFR

...parties' rights and obligations when a representation proceeding is pending? 2422.34...FEDERAL LABOR RELATIONS AUTHORITY REPRESENTATION PROCEEDINGS § 2422.34 What...parties' rights and obligations when a representation proceeding is pending? (a)...

2013-01-01

441

5 CFR 2422.34 - What are the parties' rights and obligations when a representation proceeding is pending?  

Code of Federal Regulations, 2014 CFR

...parties' rights and obligations when a representation proceeding is pending? 2422.34...FEDERAL LABOR RELATIONS AUTHORITY REPRESENTATION PROCEEDINGS § 2422.34 What...parties' rights and obligations when a representation proceeding is pending? (a)...

2014-01-01

442

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

Code of Federal Regulations, 2011 CFR

... What obligation does the retroceding Self-Governance Tribe have with respect...DEPARTMENT OF HEALTH AND HUMAN SERVICES TRIBAL SELF-GOVERNANCE Retrocession § 137.251. What obligation does the retroceding Self-Governance Tribe have with...

2011-10-01

443

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

Code of Federal Regulations, 2014 CFR

... What obligation does the retroceding Self-Governance Tribe have with respect...DEPARTMENT OF HEALTH AND HUMAN SERVICES TRIBAL SELF-GOVERNANCE Retrocession § 137.251. What obligation does the retroceding Self-Governance Tribe have with...

2014-10-01

444

33 CFR 96.490 - What further obligations exist for an organization if the Coast Guard terminates its authorization?  

Code of Federal Regulations, 2012 CFR

...obligations exist for an organization if the Coast Guard terminates its authorization...obligations exist for an organization if the Coast Guard terminates its authorization...organization receives authorization from the Coast Guard places it under certain...

2012-07-01

445

33 CFR 96.490 - What further obligations exist for an organization if the Coast Guard terminates its authorization?  

Code of Federal Regulations, 2010 CFR

...obligations exist for an organization if the Coast Guard terminates its authorization...obligations exist for an organization if the Coast Guard terminates its authorization...organization receives authorization from the Coast Guard places it under certain...

2010-07-01

446

33 CFR 96.490 - What further obligations exist for an organization if the Coast Guard terminates its authorization?  

Code of Federal Regulations, 2013 CFR

...obligations exist for an organization if the Coast Guard terminates its authorization...obligations exist for an organization if the Coast Guard terminates its authorization...organization receives authorization from the Coast Guard places it under certain...

2013-07-01

447

33 CFR 96.490 - What further obligations exist for an organization if the Coast Guard terminates its authorization?  

Code of Federal Regulations, 2014 CFR

...obligations exist for an organization if the Coast Guard terminates its authorization...obligations exist for an organization if the Coast Guard terminates its authorization...organization receives authorization from the Coast Guard places it under certain...

2014-07-01

448

33 CFR 96.490 - What further obligations exist for an organization if the Coast Guard terminates its authorization?  

Code of Federal Regulations, 2011 CFR

...obligations exist for an organization if the Coast Guard terminates its authorization...obligations exist for an organization if the Coast Guard terminates its authorization...organization receives authorization from the Coast Guard places it under certain...

2011-07-01

449

Autophagy Enhances Bacterial Clearance during P. aeruginosa Lung Infection  

PubMed Central

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

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

2013-01-01

450

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

PubMed Central

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

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

2012-01-01

451

Recognition of bacterial plant pathogens: local, systemic and transgenerational immunity.  

PubMed

Bacterial pathogens can cause multiple plant diseases and plants rely on their innate immune system to recognize and actively respond to these microbes. The plant innate immune system comprises extracellular pattern recognition receptors that recognize conserved microbial patterns and intracellular nucleotide binding leucine-rich repeat (NLR) proteins that recognize specific bacterial effectors delivered into host cells. Plants lack the adaptive immune branch present in animals, but still afford flexibility to pathogen attack through systemic and transgenerational resistance. Here, we focus on current research in plant immune responses against bacterial pathogens. Recent studies shed light onto the activation and inactivation of pattern recognition receptors and systemic acquired resistance. New research has also uncovered additional layers of complexity surrounding NLR immune receptor activation, cooperation and sub-cellular localizations. Taken together, these recent advances bring us closer to understanding the web of molecular interactions responsible for coordinating defense responses and ultimately resistance. PMID:23909802

Henry, Elizabeth; Yadeta, Koste A; Coaker, Gitta

2013-09-01

452

Recognition of bacterial plant pathogens: local, systemic and transgenerational immunity  

PubMed Central

Summary Bacterial pathogens can cause multiple plant diseases and plants rely on their innate immune system to recognize and actively respond to these microbes. The plant innate immune system is comprised of extracellular pattern recognition receptors that recognize conserved microbial patterns and intracellular nucleotide binding leucine-rich repeat (NLR) proteins that recognize specific bacterial effectors delivered into host cells. Plants lack the adaptive immune branch present in animals, but still afford flexibility to pathogen attack through systemic and transgenerational resistance. Here, we focus on current research in plant immune responses against bacterial pathogens. Recent studies shed light onto the activation and inactivation of pattern recognition receptors and systemic acquired resistance. New research has also uncovered additional layers of complexity surrounding NLR immune receptor activation, cooperation, and sub-cellular localizations. Taken together, these recent advances bring us closer to understanding the web of inter-molecular interactions responsible for coordinating defense responses and ultimately resistance. PMID:23909802

Henry, Elizabeth; Yadeta, Koste A.; Coaker, Gitta

2013-01-01

453

ABC transporters: bacterial exporters.  

PubMed Central

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

Fath, M J; Kolter, R

1993-01-01

454

The Unappreciated Intracellular Lifestyle of Blastomyces dermatitidis.  

PubMed

Blastomyces dermatitidis, a dimorphic fungus and the causative agent of blastomycosis, is widely considered an extracellular pathogen, with little evidence for a facultative intracellular lifestyle. We infected mice with spores, that is, the infectious particle, via the pulmonary route and studied intracellular residence, transition to pathogenic yeast, and replication inside lung cells. Nearly 80% of spores were inside cells at 24 h postinfection with 10(4) spores. Most spores were located inside of alveolar macrophages, with smaller numbers in neutrophils and dendritic cells. Real-time imaging showed rapid uptake of spores into alveolar macrophages, conversion to yeast, and intracellular multiplication during in vitro coculture. The finding of multiple yeast in a macrophage was chiefly due to intracellular replication rather than multiple phagocytic events or fusion of macrophages. Depletion of alveolar macrophages curtailed infection in mice infected with spores and led to a 26-fold reduction in lung CFU by 6 d postinfection versus nondepleted mice. Phase transition of the spores to yeast was delayed in these depleted mice over a time frame that correlated with reduced lung CFU. Spores cultured in vitro converted to yeast faster in the presence of macrophages than in medium alone. Thus, although advanced B. dermatitidis infection may exhibit extracellular residence in tissue, early lung infection with infectious spores reveals its unappreciated facultative intracellular lifestyle. PMID:25589071

Sterkel, Alana K; Mettelman, Robert; Wüthrich, Marcel; Klein, Bruce S

2015-02-15

455

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

456

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

457

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

Code of Federal Regulations, 2010 CFR

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

2010-07-01

458

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

459

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

Code of Federal Regulations, 2014 CFR

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

2014-07-01

460

Targeted Delivery of Antibiotics to Intracellular Chlamydial Infections using PLGA Nanoparticles  

PubMed Central

Chlamydia trachomatis and C pneumoniae are intracellular bacterial pathogens that have been shown to cause, or are strongly associated with, diverse chronic diseases. Persistent infections by both organisms are refractory to antibiotic therapy. The lack of therapeutic efficacy results from the attenuated metabolic rate of persistently infecting chlamydiae in combination with the modest intracellular drug concentrations achievable by normal delivery of antibiotics to the inclusions within which chlamydiae reside in the host cell cytoplasm. In this research, we evaluated whether nanoparticles formulated using the biodegradable poly(d-L-lactide-co-glycolide) (PLGA) polymer can enhance the delivery of antibiotics to the chlamydial inclusion complexes. We initially studied the trafficking of PLGA nanoparticles in Chlamydia-infected cells. We then evaluated nanoparticles for the delivery of antibiotics to the inclusions. Intracellular trafficking studies show that PLGA nanoparticles efficiently concentrate in inclusions in both acutely and persistently infected cells. Further, encapsulation of rifampin and azithromycin antibiotics in PLGA nanoparticles enhanced the effectiveness of the antibiotics in reducing microbial burden. Combination of rifampin and azithromycin was more effective than the individual drugs. Overall, our studies show that PLGA nanoparticles can be effective carriers for targeted delivery of antibiotics to intracellular chlamydial infections. PMID:21652065

Toti, Udaya S.; Guru, Bharath R.; Hali, Mirabela; McPharlin, Christopher; Wykes, Susan M.; Panyam, Jayanth; Whittum-Hudson, Judith A.

2011-01-01

461

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

PubMed Central

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

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

2012-01-01

462

Effect of ethyl alcohol on growth and intracellular alanine racemase of psychrotrophs.  

PubMed

The psychrotrophic alanine racemase from Pseudomonas fluorescens, a typical psychrotroph, is less resistant to organic solvents than the enzymes from thermophilic and mesophilic bacteria (Okubo et al., J. Home Econ. Jpn., 46: 1135-1140, 1995). To further elucidate this difference, we examined the effect of ethyl alcohol on the growth and intracellular alanine racemase activity of three typical psychrotrophs-P. fluorescens, Bacillus psychrosaccharolyticus and B. psychrophilus-in comparison with two mesophiles, Escherichia coli and B. subtilis. Although all the bacteria grew to the early stationary phase when cultivated at 22 degrees C for 36 h in the absence of ethyl alcohol, the growth of the psychrotrophs was more effectively suppressed by the addition of 3 and 5% ethyl alcohol to the medium than that of the mesophiles. The intracellular alanine racemase activity of the psychrotrophs was also more markedly reduced in the presence of ethyl alcohol than that of the mesophiles. When bacterial cells of each strain grown at 22 degrees C for 36 h in the absence of alcohol were suspended in 0-5 % ethyl alcohol solution and incubated at 30 degrees C for 1 h, both the survival ratio and intracellular alanine racemase activity of the psychrotrophs were lower than those of the mesophiles. Thus, ethyl alcohol effectively reduced both the growth of the psychrotrophs and their intracellular alanine racemase activity. Low concentrations of various other alcohols also repressed the growth of the psychrotrophs at 10 degrees C. PMID:16232459

Okubo, Y; Yokoigawa, K; Kawai, H

1999-01-01

463

Bacterial Toxin Effector-Membrane Targeting: Outside in, then Back Again  

PubMed Central

Pathogenic bacteria utilize multiple approaches to establish infection and mediate their toxicity to eukaryotic cells. Dedicated protein machines deposit toxic effectors directly inside the host, whereas secreted toxins must enter cells independently of other bacterial components. Regardless of how they reach the cytosol, these bacterial proteins must accurately identify their intracellular target before they can manipulate the host cell to benefit their associated bacteria. Within eukaryotic cells, post-translational modifications and individual targeting motifs spatially regulate endogenous host proteins. This review focuses on the strategies employed by bacterial effectors to associate with a frequently targeted location within eukaryotic cells, the plasma membrane. PMID:22919666

Geissler, Brett

2012-01-01

464

Bacterial Abundance Measure bacterial numbers and mass per unit volume.  

E-print Network

.37 1021 l oceans-1 Crude estimate of element fluxes (x: bacterial biomass) · Growth rate: G = xBacterial Abundance Objective · Measure bacterial numbers and mass per unit volume. · Note, we). · Plate (or viable) count (Today). · Direct count. (Thursday). #12;Why do we want to measure bacterial

Vallino, Joseph J.

465

Bacterial Abundance Measure bacterial numbers and mass per unit volume.  

E-print Network

.37 � 1021 l oceans-1 Crude estimate of element fluxes (x: bacterial biomass) · Growth rate: G = µx; µBacterial Abundance Objective · Measure bacterial numbers and mass per unit volume. · Note, we). · Plate (or viable) count (Today). · Direct count. (Thursday). #12;Why do we want to measure bacterial

Vallino, Joseph J.

466

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

Microsoft Academic Search

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

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

2000-01-01

467

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

EPA Science Inventory

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

468

Obligate symbiont involved in pest status of host insect.  

PubMed

The origin of specific insect genotypes that enable efficient use of agricultural plants is an important subject not only in applied fields like pest control and management but also in basic disciplines like evolutionary biology. Conventionally, it has been presupposed that such pest-related ecological traits are attributed to genes encoded in the insect genomes. Here, however, we report that pest status of an insect is principally determined by symbiont genotype rather than by insect genotype. A pest stinkbug species, Megacopta punctatissima, performed well on crop legumes, while a closely related non-pest species, Megacopta cribraria, suffered low egg hatch rate on the plants. When their obligate gut symbiotic bacteria were experimentally exchanged between the species, their performance on the crop legumes was, strikingly, completely reversed: the pest species suffered low egg hatch rate, whereas the non-pest species restored normal egg hatch rate and showed good performance. The low egg hatch rates were attributed to nymphal mortality before or upon hatching, which were associated with the symbiont from the non-pest stinkbug irrespective of the host insect species. Our finding sheds new light on the evolutionary origin of insect pests, potentially leading to novel approaches to pest control and management. PMID:17567556

Hosokawa, Takahiro; Kikuchi, Yoshitomo; Shimada, Masakazu; Fukatsu, Takema

2007-08-22

469

Deciphering the bacterial glycocode: recent advances in bacterial glycoproteomics  

PubMed Central

Bacterial glycoproteins represent an attractive target for new antibacterial treatments, as they are frequently linked to pathogenesis and contain distinctive glycans that are absent in humans. Despite their potential therapeutic importance, many bacterial glycoproteins remain uncharacterized. This review focuses on recent advances in deciphering the bacterial glycocode, including metabolic glycan labeling to discover and characterize bacterial glycoproteins, lectin-based microarrays to monitor bacterial glycoprotein dynamics, crosslinking sugars to assess the roles of bacterial glycoproteins, and harnessing bacterial glycosylation systems for the efficient production of industrially important glycoproteins. PMID:23276734

Longwell, Scott A.; Dube, Danielle H.

2012-01-01

470

A theoretical model of intracellular devitrification.  

PubMed

Devitrification of the intracellular solution can cause significant damage during warming of cells cryopreserved by freezing or vitrification. Whereas previous theoretical investigations of devitrification have not considered the effect of cell dehydration on intracellular ice formation, a new model which couples membrane-limited water transport equations, classical nucleation theory, and diffusion-limited crystal growth theory is presented. The model was used to explore the role of cell dehydration in devitrification of human keratinocytes frozen in the presence of glycerol. Numerical simulations demonstrated that water transport during cooling affects subsequent intracellular ice formation during warming, correctly predicting observations that critical warming rate increases with increasing cooling rate. However, for cells with a membrane transport activation energy less than approximately 50 kJ/mol, devitrification was also affected by cell dehydration during warming, leading to a reversal of the relationship between cooling rate and critical warming rate. Thus, for low warming rates (less than 10 degrees C/min for keratinocytes), the size and total volume fraction of intracellular ice crystals forming during warming decreased with decreasing warming rate, and the critical warming rate decreased with increasing cooling rate. The effects of water transport on the kinetics of intracellular nucleation and crystal growth were elucidated by comparison of simulations of cell warming with simulations of devitrification in H(2)O-NaCl-glycerol droplets of constant size and composition. These studies showed that the rate of intracellular nucleation was less sensitive to cell dehydration than was the crystal growth rate. The theoretical methods presented may be of use for the design and optimization of freeze-thaw protocols. PMID:11578115

Karlsson, J O

2001-05-01

471

cDNA-RNA subtractive hybridization reveals increased expression of mycocerosic acid synthase in intracellular Mycobacterium bovis BCG  

Microsoft Academic Search

Identifying genes that are differentially expressed by Mycobacterium bovis BCG after phagocytosis by macrophages will facilitate the understanding of the molecular mechanisms of host cell-intracellular pathogen interactions. To identify such genes a cDNA-total RNA subtractive hybridization strategy has been used that circumvents the problems both of limited availability of bacterial RNA from models of infection and the high rRNA backgrounds

Ming-Shi Li; Irene M. Monahan; Simon J. Waddell; Joseph A. Mangan; Steve L. Martin; Martin J. Everett; Philip D. Butcher

472

A Type IV Translocated Legionella Cysteine Phytase Counteracts Intracellular Growth Restriction by Phytate.  

PubMed

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

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

2014-12-01

473

Coxiella burnetii Effector Proteins That Localize to the Parasitophorous Vacuole Membrane Promote Intracellular Replication.  

PubMed

The intracellular bacterial pathogen Coxiella burnetii directs biogenesis of a parasitophorous vacuole (PV) that acquires host endolysosomal components. Formation of a PV that supports C. burnetii replication requires a Dot/Icm type 4B secretion system (T4BSS) that delivers bacterial effector proteins into the host cell cytosol. Thus, a subset of T4BSS effectors are presumed to direct PV biogenesis. Recently, the PV-localized effector protein CvpA was found to promote C. burnetii intracellular growth and PV expansion. We predict additional C. burnetii effectors localize to the PV membrane and regulate eukaryotic vesicle trafficking events that promote pathogen growth. To identify these vacuolar effector proteins, a list of predicted C. burnetii T4BSS substrates was compiled using bioinformatic criteria, such as the presence of eukaryote-like coiled-coil domains. Adenylate cyclase translocation assays revealed 13 proteins were secreted in a Dot/Icm-dependent fashion by C. burnetii during infection of human THP-1 macrophages. Four of the Dot/Icm substrates, termed Coxiella vacuolar protein B (CvpB), CvpC, CvpD, and CvpE, labeled the PV membrane and LAMP1-positive vesicles when ectopically expressed as fluorescently tagged fusion proteins. C. burnetii ?cvpB, ?cvpC, ?cvpD, and ?cvpE mutants exhibited significant defects in intracellular replication and PV formation. Genetic complementation of the ?cvpD and ?cvpE mutants rescued intracellular growth and PV generation, whereas the growth of C. burnetii ?cvpB and ?cvpC was rescued upon cohabitation with wild-type bacteria in a common PV. Collectively, these data indicate C. burnetii encodes multiple effector proteins that target the PV membrane and benefit pathogen replication in human macrophages. PMID:25422265

Larson, Charles L; Beare, Paul A; Voth, Daniel E; Howe, Dale; Cockrell, Diane C; Bastidas, Robert J; Valdivia, Raphael H; Heinzen, Robert A

2015-02-01

474

Growth of Bacterial Colonies  

NASA Astrophysics Data System (ADS)

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

Warren, Mya; Hwa, Terence

2013-03-01

475

Microfluidics for bacterial chemotaxis  

E-print Network

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

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

2011-01-01

476

Small bowel bacterial overgrowth  

MedlinePLUS

Overgrowth - intestinal bacteria; Bacterial overgrowth - intestine ... Unlike the large intestine, the small intestine does not have a high number of bacteria. When there are too many bacteria in the ...

477

Subcellular localization of marine bacterial alkaline phosphatases.  

PubMed

Bacterial alkaline phosphatases (APases) are important enzymes in organophosphate utilization in the ocean. The subcellular localization of APases has significant ecological implications for marine biota but is largely unknown. The extensive metagenomic sequence databases from the Global Ocean Sampling Expedition provide an opportunity to address this question. A bioinformatics pipeline was developed to identify marine bacterial APases from the metagenomic databases, and a consensus classification algorithm was designed to predict their subcellular localizations. We identified 3,733 bacterial APase sequences (including PhoA, PhoD, and PhoX) and found that cytoplasmic (41%) and extracellular (30%) APases exceed their periplasmic (17%), outer membrane (12%), and inner membrane (0.9%) counterparts. The unexpectedly high abundance of cytoplasmic APases suggests that the transport and intracellular hydrolysis of small organophosphate molecules is an important mechanism for bacterial acquisition of phosphorus (P) in the surface ocean. On average, each marine bacterium possessed at least one suite of uptake of glycerol phosphate (ugp) genes (e.g., ugpA, ugpB, ugpC, ugpE) for dissolved organic phosphorus (DOP) transport, but only half of them had ugpQ, which hydrolyzes transported DOP, indicating that cytoplasmic APases play a role in hydrolyzing transported DOP. The most abundant heterotrophic marine bacteria, alpha- and gamma-Proteobacteria, might hydrolyze DOP outside the cytoplasmic membrane, but the former could also transport and hydrolyze DOP in the cytoplasm. The abundant extracellular APases could provide bioavailable P for organisms that cannot directly access organophosphates, and thereby increase marine biological productivity and diversity. PMID:19926862

Luo, Haiwei; Benner, Ronald; Long, Richard A; Hu, Jianjun

2009-12-15

478

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

Microsoft Academic Search

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

Driss El Kebir; Levente József; János G. Filep

2008-01-01

479

An experimental test of preferences for nest contents in an obligate brood parasite,  

E-print Network

An experimental test of preferences for nest contents in an obligate brood parasite, Molothrus ater to examine the stimuli to which female brown-headed cowbirds (Molothrus ater) attend when selecting a nest

White, David J.

480

38 CFR 17.612 - Cancellation, waiver, or suspension of obligation.  

Code of Federal Regulations, 2014 CFR

...AFFAIRS MEDICAL Va Health Professional Scholarship Program § 17.612 Cancellation...of the obligation either to repay any scholarship funds that have already been paid...granted, then the waived amount of scholarship funds may be considered taxable...

2014-07-01

481

42 CFR 62.11 - When can a scholarship program payment obligation be discharged in bankruptcy?  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false When can a scholarship program payment obligation be discharged...TRAINING NATIONAL HEALTH SERVICE CORPS SCHOLARSHIP AND LOAN REPAYMENT PROGRAMS National Health Service Corps Scholarship Program § 62.11 When...

2011-10-01

482

48 CFR 719.273-9 - Obligations under the Mentor-Protégé Program.  

Code of Federal Regulations, 2010 CFR

...DEVELOPMENT SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS The U.S. Agency for International Development (USAID) Mentor-Protégé Program 719.273-9 Obligations...their Protégé(s) as suppliers to the Federal...

2010-10-01

483

43 CFR 3287.2 - When may BLM grant a suspension of unit obligations?  

Code of Federal Regulations, 2013 CFR

...suspension of initial drilling obligations due to a unit operator's inability to obtain an electrical sales contract, or when poor economics affect the electrical generation market, limiting the opportunity to obtain a viable sales contract. BLM may grant a...

2013-10-01

484

43 CFR 3287.2 - When may BLM grant a suspension of unit obligations?  

Code of Federal Regulations, 2012 CFR

...suspension of initial drilling obligations due to a unit operator's inability to obtain an electrical sales contract, or when poor economics affect the electrical generation market, limiting the opportunity to obtain a viable sales contract. BLM may grant a...

2012-10-01

485

47 CFR 14.61 - Obligations with respect to internet browsers built into mobile phones.  

Code of Federal Regulations, 2014 CFR

...respect to internet browsers built into mobile phones. 14.61 Section 14.61...Built Into Telephones Used With Public Mobile Services. § 14.61 Obligations with respect to internet browsers built into mobile phones. (a) Accessibility....

2014-10-01

486

49 CFR 199.239 - Operator obligation to promulgate a policy on the misuse of alcohol.  

Code of Federal Regulations, 2010 CFR

...obligation to promulgate a policy on the misuse of alcohol. 199.239 Section 199.239 Transportation...TRANSPORTATION (CONTINUED) PIPELINE SAFETY DRUG AND ALCOHOL TESTING Alcohol Misuse Prevention Program § 199.239...

2010-10-01

487

30 CFR 251.6 - Obligations and rights under a permit or a Notice.  

Code of Federal Regulations, 2010 CFR

... 251.6 Section 251.6 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE INTERIOR OFFSHORE GEOLOGICAL AND GEOPHYSICAL (G&G) EXPLORATIONS OF THE OUTER CONTINENTAL SHELF § 251.6 Obligations and rights under a...

2010-07-01

488

38 CFR 17.609 - Pay during period of obligated service.  

Code of Federal Regulations, 2014 CFR

...17.609 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS MEDICAL Va Health Professional Scholarship Program § 17.609 Pay during period of obligated service. The initial appointment of physicians for...

2014-07-01

489

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

Code of Federal Regulations, 2014 CFR

...5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION INTERGOVERNMENTAL REVIEW OF THE NATIONAL SCIENCE FOUNDATION PROGRAMS AND ACTIVITIES § 660.5 What is the Director's obligation...

2014-10-01

490

78 FR 63276 - Interim Policy, FAA Review of Solar Energy System Projects on Federally Obligated Airports  

Federal Register 2010, 2011, 2012, 2013, 2014

...obligated airports to construct solar energy systems on airport property. FAA is adopting...ocular impact of proposed solar energy systems which are effective upon publication...henceforth referred to as solar energy systems) are designed to absorb...

2013-10-23

491

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

Code of Federal Regulations, 2010 CFR

... Assurances and obligations of H-2A Labor Contractors. 655...Employment in the United States (H-2A Workers) § 655.1306...S.C. 1841 and 29 CFR part 500, subpart D, except where workers...as described in §...

2010-04-01

492

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

Code of Federal Regulations, 2012 CFR

... Assurances and obligations of H-2A Labor Contractors. 655...Employment in the United States (H-2A Workers) § 655.1306...S.C. 1841 and 29 CFR part 500, subpart D, except where workers...as described in §...

2012-04-01

493

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

Code of Federal Regulations, 2011 CFR

... Assurances and obligations of H-2A Labor Contractors. 655...Employment in the United States (H-2A Workers) § 655.1306...S.C. 1841 and 29 CFR part 500, subpart D, except where workers...as described in §...

2011-04-01

494

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

Code of Federal Regulations, 2013 CFR

... Assurances and obligations of H-2A Labor Contractors. 655...Employment in the United States (H-2A Workers) § 655.1306...S.C. 1841 and 29 CFR part 500, subpart D, except where workers...as described in §...

2013-04-01

495

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

Code of Federal Regulations, 2014 CFR

... Assurances and obligations of H-2A Labor Contractors. 655...Employment in the United States (H-2A Workers) § 655.1306...S.C. 1841 and 29 CFR part 500, subpart D, except where workers...as described in §...

2014-04-01

496

26 CFR 25.2516-2 - Transfers in settlement of support obligations.  

Code of Federal Regulations, 2010 CFR

...settlement of support obligations. Transfers to provide a reasonable allowance for the support of children (including legally adopted children) of a marriage during minority are not subject to the gift tax if made pursuant to an agreement which...

2010-04-01

497

25 CFR 163.42 - Obligated service and breach of contract.  

Code of Federal Regulations, 2011 CFR

...obligated service to pursue postgraduate or postdoctoral studies. In such cases, the Secretary shall issue a decision within 30 days...postgraduation recruitment program. (5) Postgraduate studies program —Amount plus interest equal to the...

2011-04-01

498

25 CFR 163.42 - Obligated service and breach of contract.  

Code of Federal Regulations, 2013 CFR

...obligated service to pursue postgraduate or postdoctoral studies. In such cases, the Secretary shall issue a decision within 30 days...postgraduation recruitment program. (5) Postgraduate studies program —Amount plus interest equal to the...

2013-04-01

499

25 CFR 163.42 - Obligated service and breach of contract.  

Code of Federal Regulations, 2012 CFR

...obligated service to pursue postgraduate or postdoctoral studies. In such cases, the Secretary shall issue a decision within 30 days...postgraduation recruitment program. (5) Postgraduate studies program —Amount plus interest equal to the...

2012-04-01

500

25 CFR 163.42 - Obligated service and breach of contract.  

Code of Federal Regulations, 2010 CFR

...obligated service to pursue postgraduate or postdoctoral studies. In such cases, the Secretary shall issue a decision within 30 days...postgraduation recruitment program. (5) Postgraduate studies program —Amount plus interest equal to the...

2010-04-01