Modulation of Gene Expression in Actinobacillus pleuropneumoniae Exposed to Bronchoalveolar Fluid

PubMed Central

Lone, Abdul G.; Deslandes, Vincent; Nash, John H. E.; Jacques, Mario; MacInnes, Janet I.

2009-01-01

Background Actinobacillus pleuropneumoniae, the causative agent of porcine contagious pleuropneumonia, is an important pathogen of swine throughout the world. It must rapidly overcome the innate pulmonary immune defenses of the pig to cause disease. To better understand this process, the objective of this study was to identify genes that are differentially expressed in a medium that mimics the lung environment early in the infection process. Methods and Principal Findings Since bronchoalveolar lavage fluid (BALF) contains innate immune and other components found in the lungs, we examined gene expression of a virulent serovar 1 strain of A. pleuropneumoniae after a 30 min exposure to BALF, using DNA microarrays and real-time PCR. The functional classes of genes found to be up-regulated most often in BALF were those encoding proteins involved in energy metabolism, especially anaerobic metabolism, and in cell envelope, DNA, and protein biosynthesis. Transcription of a number of known virulence genes including apxIVA and the gene for SapF, a protein which is involved in resistance to antimicrobial peptides, was also up-regulated in BALF. Seventy-nine percent of the genes that were up-regulated in BALF encoded a known protein product, and of these, 44% had been reported to be either expressed in vivo and/or involved in virulence. Conclusions The results of this study suggest that in early stages of infection, A. pleuropneumoniae may modulate expression of genes involved in anaerobic energy generation and in the synthesis of proteins involved in cell wall biogenesis, as well as established virulence factors. Given that many of these genes are thought to be expressed in vivo or involved in virulence, incubation in BALF appears, at least partially, to simulate in vivo conditions and may provide a useful medium for the discovery of novel vaccine or therapeutic targets. PMID:19578537

Actinobacillus pleuropneumoniae grows as aggregates in the lung of pigs: is it time to refine our in vitro biofilm assays?

PubMed

Tremblay, Yannick D N; Labrie, Josée; Chénier, Sonia; Jacques, Mario

2017-07-01

Actinobacillus pleuropneumoniae causes porcine pleuropneumonia and forms biofilms in vitro on abiotic surfaces; however, presence of biofilms during infections has not been documented. The aim of this study was to use a species-specific fluorescent oligonucleotide probe and confocal microscopy to localize A. pleuropneumoniae in the lungs of two naturally infected pigs. Actinobacillus pleuropneumoniae was detected by fluorescence in situ hybridization and observed to grow as aggregates (~30-45 μm) during a natural infection. As the A. pleuropneumoniae aggregates observed in porcine lungs differed from the biofilms grown on a solid surface obtained in vitro, we designed a new biofilm assay using agarose, a porous substrate, favouring the formation of aggregates. In this study, we described for the first time the mode of growth of A. pleuropneumoniae during a natural infection in pigs. We also propose an in vitro biofilm assay for A. pleuropneumoniae using a porous substrate which allows the formation of aggregates. This assay might be more representative of the in vivo situation, at least in terms of the size of the bacterial aggregates and the presence of a porous matrix, and could potentially be used to test the susceptibility of A. pleuropneumoniae aggregates to antibiotics and disinfectants. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Serotyping of Actinobacillus pleuropneumoniae serotype 5 strains using a monoclonal-based polystyrene agglutination test.

PubMed Central

Dubreuil, J D; Letellier, A; Stenbaek, E; Gottschalk, M

1996-01-01

A polystyrene agglutination test has been developed for serotyping Actinobacillus pleuropneumoniae serotype 5a and 5b strains. Protein A-coated polystyrene microparticles were sensitized with a murine monoclonal antibody recognizing an epitope on serotype 5 LPS-O chain as shown by SDS-PAGE and Western blotting. A total of 205 A. pleuropneumoniae, strains including all 12 serotype reference strains and 13 strains representing 8 common bacterial species associated with swine or related to A. pleuropneumoniae, were tested by mixing 25 microL of polystyrene reagent with the same volume of a dense suspension of bacterial cells grown for 18 h. All A. pleuropneumoniae strains had been previously serotyped using standard procedures. The polystyrene agglutination test was rapid (less than 3 min) and easy to perform. Overall a very good correlation (97.3%) with the standard techniques was found. The sensitized polystyrene particles were stable for at least 6 mo. Images Figure 1. PMID:8825998

Specific Humoral Immune Response Induced by Propionibacterium acnes Can Prevent Actinobacillus pleuropneumoniae Infection in Mice

PubMed Central

Yang, Feng; Ma, Qiuyue; Huang, Jing; Ji, Qun; Zhai, Ruidong; Wang, Lei; Wang, Yu; Li, Linxi; Sun, Changjiang; Feng, Xin; Han, Wenyu

2014-01-01

Porcine contagious pleuropneumonia, caused by Actinobacillus pleuropneumoniae, has a major impact on economics, ecology, and animal welfare in the pig-rearing industry. Propionibacterium acnes, a facultative anaerobic Gram-positive corynebacterium, exists widely in normal healthy adult animals. We have shown previously that P. acnes can prevent A. pleuropneumoniae infections in mice and pigs. To elucidate the mechanism of this effect and to identify novel A. pleuropneumoniae vaccines, the role of anti-P. acnes antibodies in preventing infection was analyzed by indirect immunofluorescence and opsonophagocytosis assays in vitro. The role of the specific humoral immune response induced by P. acnes was confirmed in a B cell depletion mouse model. The survival rates of mice challenged with A. pleuropneumoniae exhibited a highly significant positive rank correlation with the levels of anti-P. acnes antibodies. The specific antibodies induced by P. acnes had the ability to combine with A. pleuropneumoniae and increase opsonization of A. pleuropneumoniae for phagocytosis. Furthermore, analysis in the murine B cell depletion model confirmed that the humoral immune response induced by P. acnes played an important role in resistance to A. pleuropneumoniae infection. In this study, we further elucidated the reasons that P. acnes can prevent A. pleuropneumoniae infection, which provides useful evidence for the development of heterologous vaccines for the control of porcine contagious pleuropneumonia. PMID:24429068

Multiplex analysis of pro-inflammatory cytokines in serum of Actinobacillus pleuropneumoniae-infected pigs.

PubMed

Wyns, H; Croubels, S; Vandekerckhove, M; Demeyere, K; De Backer, P; Goddeeris, B M; Meyer, E

2015-10-01

Porcine pleuropneumonia is a severe respiratory disease caused by Actinobacillus (A.) pleuropneumoniae. The aim of the present study was to analyze serum samples of A. pleuropneumoniae-infected pigs for TNF-α, IL-1β and IL-6 using a cytometric bead array (CBA) 3-plex assay and additionally for IL-6 using ELISA. The CBA 3-plex assay was successfully validated for use in serum. The limits of detection varied between 0.012 and 0.333 ng/mL, and the inter- and inter-assay coefficients of variation were <5% and <10%, respectively. Increased levels were observed for all 3 cytokines following experimental infection with A. pleuropneumoniae. Mean peak concentrations of TNF-α and IL-6 were recorded at 12h and at 10h p.i., respectively. For IL-6, similar concentration-time profiles were observed with CBA and ELISA. It is proposed that this immuno-assay can be applied for the screening of immunomodulatory properties of drugs and vaccine adjuvants in infection, inflammation and vaccination. Copyright © 2015 Elsevier Ltd. All rights reserved.

Plasmid mediated antimicrobial resistance in Ontario isolates of Actinobacillus (Haemophilus) pleuropneumoniae.

PubMed Central

Gilbride, K A; Rosendal, S; Brunton, J L

1989-01-01

The genetic basis of antimicrobial resistance in Ontario isolates of Actinobacillus (Haemophilus) pleuropneumoniae was studied. Two Ontario isolates of A. pleuropneumoniae were found to be resistant to sulfonamides (Su), streptomycin (Sm) and ampicillin (Amp). Resistance to Su and Sm was specified by a 2.3 megadalton (Mdal) plasmid which appeared to be identical to pVM104, which has been described in isolates of A. pleuropneumoniae from South Dakota. Southern hybridization showed that the 2.3 Mdal Su Sm plasmid was highly related to those Hinc II fragments of RSF1010 known to carry the Su Sm genes, but was unrelated to the remainder of this Salmonella resistance plasmid. Resistance to Su and Amp was specified by a 3.5 Mdal plasmid and appeared identical to pVM105 previously reported. The beta-lactamase enzyme had an isoelectric point of approximately 9.0. Southern hybridization showed no relationship to the TEM beta-lactamase. A third isolate of A. pleuropneumoniae was found to be resistant to chloramphenicol (Cm), Su and Sm by virtue of a 3.0 Mdal plasmid which specified a chloramphenicol acetyl transferase. We conclude that resistance to Su, Sm, Amp and Cm is mediated by small plasmids in A. pleuropneumoniae. Although the Su and Sm resistance determinants are highly related to those found in Enterobacteriaceae, the plasmids themselves and the beta-lactamase determinant are different. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. PMID:2914226

Poly-N-acetylglucosamine mediates biofilm formation and antibiotic resistance in Actinobacillus pleuropneumoniae

PubMed Central

Izano, Era A.; Sadovskaya, Irina; Vinogradov, Evgeny; Mulks, Martha H.; Velliyagounder, Kabilan; Ragunath, Chandran; Kher, William B.; Ramasubbu, Narayanan; Jabbouri, Saïd; Perry, Malcolm B.; Kaplan, Jeffrey B.

2007-01-01

Most field isolates of the swine pathogen Actinobacillus pleuropneumoniae form tenacious biofilms on abiotic surfaces in vitro. We purified matrix polysaccharides from biofilms produced by A. pleuropneumoniae field isolates IA1 and IA5 (serotypes 1 and 5, respectively), and determined their chemical structures by using NMR spectroscopy. Both strains produced matrix polysaccharides consisting of linear chains of N-acetyl-D-glucosamine (GlcNAc) residues in β(1,6) linkage (poly-β-1,6-GlcNAc or PGA). A small percentage of the GlcNAc residues in each polysaccharide were N-deacetylated. These structures were nearly identical to those of biofilm matrix polysaccharides produced by Escherichia coli, Staphylococcus aureus and S. epidermidis. PCR analyses indicated that a gene encoding the PGA-specific glycoside transferase enzyme PgaC was present on the chromosome of 15 out of 15 A. pleuropneumoniae reference strains (serotypes 1-12) and 76 out of 77 A. pleuropneumoniae field isolates (serotypes 1, 5 and 7). A pgaC mutant of strain IA5 failed to form biofilms in vitro, as did wild-type strains IA1 and IA5 when grown in broth supplemented with the PGA-hydrolyzing enzyme dispersin B. Treatment of IA5 biofilms with dispersin B rendered them more sensitive to killing by ampicillin. Our findings suggest that PGA functions as a major biofilm adhesin in A. pleuropneumoniae. Biofilm formation may have relevance to the colonization and pathogenesis of A. pleuropneumoniae in pigs. PMID:17412552

Antimicrobial susceptibility of Actinobacillus pleuropneumoniae isolates from clinical outbreaks of porcine respiratory diseases.

PubMed

Kucerova, Z; Hradecka, H; Nechvatalova, K; Nedbalcova, K

2011-05-12

Limited data regarding the susceptibility of Actinobacillus pleuropneumoniae to antimicrobials has been published during recent years. Accordingly, the aim of the present study was to investigate the distribution of MICs for the isolates of A. pleuropneumoniae from diseased pigs in the Czech Republic between 2007 and 2009. A total of 242 isolates were tested for susceptibility to 16 antimicrobial agents by a broth microdilution method. A low degree of resistance was observed for florfenicol (0.8%), amoxicillin and clavulanic acid (0.8%), tilmicosin (1.2%), tiamulin (1.7%) and ampicillin (3.3%), whereas resistance to tetracycline was detected more frequently, 23.9% of isolates. Interestingly, resistance to florfenicol has not yet been reported in any study investigating antimicrobial resistance of A. pleuropneumoniae. By PCR the presence of the floR gene was confirmed in all florfenicol resistant isolates. Copyright © 2011 Elsevier B.V. All rights reserved.

Efficacy of tilmicosin in the control of experimentally induced Actinobacillus pleuropneumoniae infection in swine.

PubMed

Paradis, Marie-Anne; Vessie, Gordon H; Merrill, John K; Dick, C Paul; Moore, Camille; Charbonneau, George; Gottschalk, M; MacInnes, Janet I; Higgins, Robert; Mittal, K R; Girard, C; Aramini, Jeffery J; Wilson, Jeffrey B

2004-01-01

The efficacy of tilmicosin administered in the feed to control Actinobacillus pleuropneumoniae infections in pigs was evaluated through a multisite, multitrial study. For each of 6 trials, 48 pigs (stratified by weight and sex) were randomly assigned to 6 to 8 pens. Medicated feed containing tilmicosin (200 g/t) and unmedicated feed were randomly assigned at the pen level and were provided ad libitum from day -7 to trial termination (day 14). Seeder pigs (inoculated intranasally with A. pleuropneumoniae serotype 1 and showing signs of clinical disease) were introduced to each pen on day 0. Rates of death, gross lesions, and culture of A. pleuropneumoniae at necropsy, clinical scores, average daily gain in weight, and average body temperature were compared between the medicated and unmedicated pigs. Compared with the unmedicated pigs, significantly fewer (P < 0.05) pigs given tilmicosin had lesions typical of A. pleuropneumoniae or had A. pleuropneumoniae isolated from their tissues at necropsy. Together with a significant reduction (P < 0.05) in the average percentage of pneumonic lung involvement (both visually and by weight), there were reductions in the numbers of pigs with moderate and severe pneumonic lung lesions and with A. pleuropneumoniae associated mortality. With tilmicosin treatment, the average daily weight gain, daily temperature, abdominal appearance, attitude, and respiration were also significantly better (P < 0.05). The results of this study demonstrate the in vivo effectiveness of tilmicosin (200 g/t) in controlling pleuropneumonia among swine experimentally infected with A. pleuropneumoniae.

[Cu,Zn]-Superoxide Dismutase Mutants of the Swine Pathogen Actinobacillus pleuropneumoniae Are Unattenuated in Infections of the Natural Host

PubMed Central

Sheehan, Brian J.; Langford, Paul R.; Rycroft, Andrew N.; Kroll, J. Simon

2000-01-01

Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, contains a periplasmic Cu- and Zn-cofactored superoxide dismutase ([Cu,Zn]-SOD, or SodC) which has the potential, realized in other pathogens, to promote bacterial survival during infection by dismutating host-defense-derived superoxide. Here we describe the construction of a site-specific, [Cu,Zn]-SOD-deficient A. pleuropneumoniae serotype 1 mutant and show that although the mutant is highly sensitive to the microbicidal action of superoxide in vitro, it remains fully virulent in experimental pulmonary infection in pigs. PMID:10899887

The challenge of detecting herds sub-clinically infected with Actinobacillus pleuropneumoniae.

PubMed

Gottschalk, Marcelo

2015-10-01

The introduction into a naïve herd of animals sub-clinically infected with Actinobacillus pleuropneumoniae (App) is frequently the cause of clinical pleuropneumonia and the identification of such infected herds is a priority in the control of disease. Different serological tests for App have been developed and a number of these are routinely used. Some are species-specific whereas others identify more specifically the serotype/serogroup involved which requires updated information about important serotypes recovered from diseased pigs in a given area/country. Serotyping methods based on molecular techniques have been developed lately and are ready to be used by most diagnostic laboratories. When non-conclusive serological results are obtained, direct detection of App from tonsils is sometimes attempted. This review addresses different techniques and approaches used to monitor herds sub-clinically infected by this important pathogen. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of diagnostic assays for the serological detection of Actinobacillus pleuropneumoniae on samples of known or unknown exposure.

PubMed

Opriessnig, Tanja; Hemann, Michelle; Johnson, John K; Heinen, Sheila; Giménez-Lirola, Luis G; O'Neill, Kevin C; Hoang, Hai; Yoon, Kyoung-Jin; Gottschalk, Marcelo; Halbur, Patrick G

2013-01-01

Accurate diagnosis of exposure to Actinobacillus pleuropneumoniae is important for maintaining negative farms. In the present study, the ability of a dual-plate complement fixation (CF) assay and 3 commercially available enzyme-linked immunosorbent assays (ELISAs; quad-plate ELISA-1, single-plate ELISA-2, and single-plate ELISA-3) in detecting serological evidence of A. pleuropneumoniae exposure was compared using serum samples of experimentally infected or vaccinated pigs, or field samples from the United States. Forty-two pigs were divided into groups of 2 pigs and were inoculated with 1 of 15 A. pleuropneumoniae strains representing all known serovars of A. pleuropneumoniae, or with Actinobacillus suis, or were vaccinated with a bacterin containing A. pleuropneumoniae serovar 1, 3, 5, or 7. Serum samples collected at the day of inoculation or vaccination and 7, 14, 21, and 28 days later were used to compare the assays. On samples from experimentally infected pigs, the dual-plate CF assay, quad-plate ELISA-1, single-plate ELISA-2, and single-plate ELISA-3 had sensitivities of 0.46, 0.74, 0.13, and 0.13 and specificities of 0.90, 1.0, 1.0, and 1.0, respectively. Vaccinated pigs were identified only by the dual-plate CF assay and the quad-plate ELISA-1. In addition, 90 serum samples with unknown A. pleuropneumoniae exposure collected under field conditions were tested with all assays. The agreement of the 4 assays on field samples was slight to fair. While several assays are available for demonstration of A. pleuropneumoniae exposure, differences in assay targets complicate test choices. Decisions on which assay or combination of assays to use depend on the specific reasons for running the assays.

Efficacy of tilmicosin in the control of experimentally induced Actinobacillus pleuropneumoniae infection in swine

PubMed Central

2004-01-01

Abstract The efficacy of tilmicosin administered in the feed to control Actinobacillus pleuropneumoniae infections in pigs was evaluated through a multisite, multitrial study. For each of 6 trials, 48 pigs (stratified by weight and sex) were randomly assigned to 6 to 8 pens. Medicated feed containing tilmicosin (200 g/t) and unmedicated feed were randomly assigned at the pen level and were provided ad libitum from day −7 to trial termination (day 14). Seeder pigs (inoculated intranasally with A. pleuropneumoniae serotype 1 and showing signs of clinical disease) were introduced to each pen on day 0. Rates of death, gross lesions, and culture of A. pleuropneumoniae at necropsy, clinical scores, average daily gain in weight, and average body temperature were compared between the medicated and unmedicated pigs. Compared with the unmedicated pigs, significantly fewer (P < 0.05) pigs given tilmicosin had lesions typical of A. pleuropneumoniae or had A. pleuropneumoniae isolated from their tissues at necropsy. Together with a significant reduction (P < 0.05) in the average percentage of pneumonic lung involvement (both visually and by weight), there were reductions in the numbers of pigs with moderate and severe pneumonic lung lesions and with A. pleuropneumoniae associated mortality. With tilmicosin treatment, the average daily weight gain, daily temperature, abdominal appearance, attitude, and respiration were also significantly better (P < 0.05). The results of this study demonstrate the in vivo effectiveness of tilmicosin (200 g/t) in controlling pleuropneumonia among swine experimentally infected with A. pleuropneumoniae. PMID:14979429

Actinobacillus pleuropneumoniae Iron Transport and Urease Activity: Effects on Bacterial Virulence and Host Immune Response

PubMed Central

Baltes, Nina; Tonpitak, Walaiporn; Gerlach, Gerald-F.; Hennig-Pauka, Isabel; Hoffmann-Moujahid, Astrid; Ganter, Martin; Rothkötter, Hermann-J.

2001-01-01

Actinobacillus pleuropneumoniae, a porcine respiratory tract pathogen, has been shown to express transferrin-binding proteins and urease during infection. Both activities have been associated with virulence; however, their functional role for infection has not yet been elucidated. We used two isogenic A. pleuropneumoniae single mutants (ΔexbB and ΔureC) and a newly constructed A. pleuropneumoniae double (ΔureC ΔexbB) mutant in aerosol infection experiments. Neither the A. pleuropneumoniae ΔexbB mutant nor the double ΔureC ΔexbB mutant was able to colonize sufficiently long to initiate a detectable humoral immune response. These results imply that the ability to utilize transferrin-bound iron is required for multiplication and persistence of A. pleuropneumoniae in the porcine respiratory tract. The A. pleuropneumoniae ΔureC mutant and the parent strain both caused infections that were indistinguishable from one another in the acute phase of disease; however, 3 weeks postinfection the A. pleuropneumoniae ΔureC mutant, in contrast to the parent strain, could not be isolated from healthy lung tissue. In addition, the local immune response—as assessed by fluorescence-activated cell sorter and enzyme-linked immunosorbent spot analyses—revealed a significantly higher number of A. pleuropneumoniae-specific B cells in the bronchoalveolar lavage fluid (BALF) of pigs infected with the A. pleuropneumoniae ΔureC mutant than in the BALF of those infected with the parent strain. These results imply that A. pleuropneumoniae urease activity may cause sufficient impairment of the local immune response to slightly improve the persistence of the urease-positive A. pleuropneumoniae parent strain. PMID:11119539

Simultaneous detection of antibodies to five Actinobacillus pleuropneumoniae serovars using bead-based multiplex analysis.

PubMed

Berger, Sanne Schou; Lauritsen, Klara Tølbøll; Boas, Ulrik; Lind, Peter; Andresen, Lars Ole

2017-11-01

We developed and made a preliminary validation of a bead-based multiplexed immunoassay for simultaneous detection of porcine serum antibodies to Actinobacillus pleuropneumoniae serovars 1, 2, 6, 7, and 12. Magnetic fluorescent beads were coupled with A. pleuropneumoniae antigens and tested with a panel of serum samples from experimentally infected pigs and with serum samples from uninfected and naturally infected pigs. The multiplex assay was compared to in-house ELISAs and complement fixation (CF) tests, which have been used for decades as tools for herd classification in the Danish Specific Pathogen Free system. Assay specificities and sensitivities as well as the corresponding cutoff values were determined using receiver operating characteristic (ROC) curve analysis, and the A. pleuropneumoniae multiplex assay showed good correlation with the in-house ELISAs and CF tests with areas under ROC curves ≥ 0.988. Benefits of multiplexed assays compared to ELISAs and CF tests include reduced serum sample volumes needed for analysis, less labor, and shorter assay time.

Pathway deregulation and expression QTLs in response to Actinobacillus pleuropneumoniae infection in swine.

PubMed

Reiner, Gerald; Dreher, Felix; Drungowski, Mario; Hoeltig, Doris; Bertsch, Natalie; Selke, Martin; Willems, Hermann; Gerlach, Gerald Friedrich; Probst, Inga; Tuemmler, Burkhardt; Waldmann, Karl-Heinz; Herwig, Ralf

2014-12-01

Actinobacillus (A.) pleuropneumoniae is among the most important pathogens in pig. The agent causes severe economic losses due to decreased performance, the occurrence of acute or chronic pleuropneumonia, and an increase in death incidence. Since therapeutics cannot be used in a sustainable manner, and vaccination is not always available, new prophylactic measures are urgently needed. Recent research has provided evidence for a genetic predisposition in susceptibility to A. pleuropneumoniae in a Hampshire × German Landrace F2 family with 170 animals. The aim of the present study is to characterize the expression response in this family in order to unravel resistance and susceptibility mechanisms and to prioritize candidate genes for future fine mapping approaches. F2 pigs differed distinctly in clinical, pathological, and microbiological parameters after challenge with A. pleuropneumoniae. We monitored genome-wide gene expression from the 50 most and 50 least susceptible F2 pigs and identified 171 genes differentially expressed between these extreme phenotypes. We combined expression QTL analyses with network analyses and functional characterization using gene set enrichment analysis and identified a functional hotspot on SSC13, including 55 eQTL. The integration of the different results provides a resource for candidate prioritization for fine mapping strategies, such as TF, TFRC, RUNX1, TCN1, HP, CD14, among others.

Antimicrobial susceptibility and serotypes of Actinobacillus (Haemophilus) pleuropneumoniae recovered from Missouri swine.

PubMed

Fales, W H; Morehouse, L G; Mittal, K R; Bean-Knudsen, C; Nelson, S L; Kintner, L D; Turk, J R; Turk, M A; Brown, T P; Shaw, D P

1989-01-01

The antimicrobial susceptibility of 73 Actinobacillus (Haemophilus) pleuropneumoniae isolates from swine in Missouri was determined with a microdilution minimal inhibitory concentration test system. Serotyping was accomplished by means of co-agglutination. Serotype 1 (39/73) and serotype 5 (30/73) were commonly found, whereas serotype 7 (4/73) was infrequently encountered. Most isolates (MIC90) were found susceptible to ampicillin (amoxicillin), cephalothin, penicillin, erythromycin, gentamicin, and kanamycin. Marked resistance was found with oxytetracycline, tylosin, and sulfadimethoxine. The data indicate that use of ampicillin (amoxicillin) or penicillin may correlate well with the favorable outcome of treatment.

Differential cellular immune response of Galleria mellonella to Actinobacillus pleuropneumoniae.

PubMed

Arteaga Blanco, Luis Andrés; Crispim, Josicelli Souza; Fernandes, Kenner Morais; de Oliveira, Leandro Licursi; Pereira, Monalessa Fábia; Bazzolli, Denise Mara Soares; Martins, Gustavo Ferreira

2017-10-01

In the present work, we have investigate the cellular immune response of Galleria mellonella larvae against three strains of the gram-negative bacterium Actinobacillus pleuropneumoniae: low-virulence (780), high-virulence (1022) and the serotype 8 reference strain (R8). Prohemocytes, plasmatocytes, granulocytes, oenocytoids and spherulocytes were distinguished according to their size and morphology, their molecular markers and dye-staining properties and their role in the immune response. Total hemocyte count, differential hemocyte count, lysosome activity, autophagic response, cell viability and caspase-3 activation were determined in circulating hemocytes of naive and infected larvae. The presence of the autophagosome protein LC3 A/B within the circulating hemocytes of G. mellonella was dependent on and related to the infecting A. pleuropneumoniae strain and duration of infection. Hemocytes treated with the high-virulence strain expressed higher levels of LC3 A/B, whereas treatment with the low-virulence strain induced lower expression levels of this protein in the cells. Moreover, our results showed that apoptosis in circulating hemocytes of G. mellonella larvae after exposure to virulent bacterial strains occurred simultaneously with excessive cell death response induced by stress and subsequent caspase-3 activation.

Production and immunogenicity of Actinobacillus pleuropneumoniae ApxIIA protein in transgenic rice callus.

PubMed

Kim, Mi-Young; Kim, Tae-Geum; Yang, Moon-Sik

2017-04-01

Actinobacillus pleuropneumoniae is a major etiological agent that is responsible for swine pleuropneumonia, a highly contagious respiratory infection that causes severe economic losses in the swine production industry. ApxIIA is one of the virulence factors in A. pleuropneumoniae and has been considered as a candidate for developing a vaccine against the bacterial infection. A gene encoding an ApxIIA fragment (amino acids 439-801) was modified based on a plant-optimized codon and constructed into a plant expression vector under the control of a promoter and the 3' UTR of the rice amylase 3D gene. The plant expression vector was introduced into rice embryogenic callus (Oryza sativa L. cv. Dongjin) via particle bombardment-mediated transformation. The integration and transcription of the ApxIIA 439-801 gene were confirmed by using genomic DNA PCR amplification and Northern blot analysis, respectively. The synthesis of ApxIIA 439-801 antigen protein in transgenic rice callus was confirmed by western blot analysis. The concentration of antigen protein in lyophilized samples of transgenic rice callus was 250 μg/g. Immunizing mice with protein extracts from transgenic plants intranasally elicited secretory IgA. These results demonstrate the feasibility of using a transgenic plant to elicit immune responses against A. pleuropneumoniae. Copyright © 2017 Elsevier Inc. All rights reserved.

Quantum dot-based western blot for sensitive detection of pig serum antibody to actinobacillus pleuropneumoniae

NASA Astrophysics Data System (ADS)

Cişmileanu, Ana; Sima, Cornelia; Grigoriu, Constantin

2007-08-01

A quantum dot - immunoglobulin conjugate specific for pig IgG, was obtained by carbodiimide chemistry. We used a Western blot technique for detecting specific antibodies against Actinobacillus pleuropneumoniae (A. pp), which cause porcine pleuropneumonia. The antigen used in this technique was Apx haemolysin which is an important virulence factor of A. pp and it induces protective immunity in vaccined pigs. The detection on Western blot membrane was possible at 1/50 dilution of quantum dot conjugate at a dilution of pig serum till 1/6400. The results for pig serum demonstrated a higher sensitivity of QD-based Western blot technique for the presence of antibodies specific for Apx haemolysin in comparison with similar classical techniques (with coloured substrate for enzyme present in secondary antibody conjugate).

Outer membrane lipoprotein VacJ is required for the membrane integrity, serum resistance and biofilm formation of Actinobacillus pleuropneumoniae.

PubMed

Xie, Fang; Li, Gang; Zhang, Wanjiang; Zhang, Yanhe; Zhou, Long; Liu, Shuanghong; Liu, Siguo; Wang, Chunlai

2016-02-01

The outer membrane proteins of Actinobacillus pleuropneumoniae are mediators of infection, acting as targets for the host's defense system. The outer membrane lipoprotein VacJ is involved in serum resistance and intercellular spreading in several pathogenic bacteria. To investigate the role of VacJ in the pathogenicity of Actinobacillus pleuropneumoniae, the vacJ gene-deletion mutant MD12 ΔvacJ was constructed. The increased susceptibility to KCl, SDS plus EDTA, and several antibiotics in the MD12ΔvacJ mutant suggested that the stability of the outer membrane was impaired as a result of the mutation in the vacJ gene. The increased NPN fluorescence and significant cellular morphological variation in the MD12ΔvacJ mutant further demonstrated the crucial role of the VacJ lipoprotein in maintaining the outer membrane integrity of A. pleuropneumoniae. In addition, the MD12ΔvacJ mutant exhibited decreased survival from the serum and complement killing compared to the wild-type strain. Interestingly, the MD12ΔvacJ mutant showed reduced biofilm formation compared to the wild-type strain. To our knowledge, this is the first description of the VacJ lipoprotein contributing to bacterial biofilm formation. The data presented in this study illustrate the important role of the VacJ lipoprotein in the maintenance of cellular integrity, serum resistance, and biofilm formation in A. pleuropneumoniae. Copyright © 2015 Elsevier B.V. All rights reserved.

Host-pathogen interplay at primary infection sites in pigs challenged with Actinobacillus pleuropneumoniae.

PubMed

Sassu, Elena L; Frömbling, Janna; Duvigneau, J Catharina; Miller, Ingrid; Müllebner, Andrea; Gutiérrez, Ana M; Grunert, Tom; Patzl, Martina; Saalmüller, Armin; von Altrock, Alexandra; Menzel, Anne; Ganter, Martin; Spergser, Joachim; Hewicker-Trautwein, Marion; Verspohl, Jutta; Ehling-Schulz, Monika; Hennig-Pauka, Isabel

2017-02-28

Actinobacillus (A.) pleuropneumoniae is the causative agent of porcine pleuropneumonia and causes significant losses in the pig industry worldwide. Early host immune response is crucial for further progression of the disease. A. pleuropneumoniae is either rapidly eliminated by the immune system or switches to a long-term persistent form. To gain insight into the host-pathogen interaction during the early stages of infection, pigs were inoculated intratracheally with A. pleuropneumoniae serotype 2 and humanely euthanized eight hours after infection. Gene expression studies of inflammatory cytokines and the acute phase proteins haptoglobin, serum amyloid A and C-reactive protein were carried out by RT-qPCR from the lung, liver, tonsils and salivary gland. In addition, the concentration of cytokines and acute phase proteins were measured by quantitative immunoassays in bronchoalveolar lavage fluid, serum and saliva. In parallel to the analyses of host response, the impact of the host on the bacterial pathogen was assessed on a metabolic level. For the latter, Fourier-Transform Infrared (FTIR-) spectroscopy was employed. Significant cytokine and acute phase protein gene expression was detected in the lung and the salivary gland however this was not observed in the tonsils. In parallel to the analyses of host response, the impact of the host on the bacterial pathogen was assessed on a metabolic level. For the latter investigations, Fourier-Transform Infrared (FTIR-) spectroscopy was employed. The bacteria isolated from the upper and lower respiratory tract showed distinct IR spectral patterns reflecting the organ-specific acute phase response of the host. In summary, this study implies a metabolic adaptation of A. pleuropneumoniae to the porcine upper respiratory tract already during early infection, which might indicate a first step towards the persistence of A. pleuropneumoniae. Not only in lung, but also in the salivary gland an increased inflammatory gene expression

Experimental Identification of Actinobacillus pleuropneumoniae Strains L20 and JL03 Heptosyltransferases, Evidence for a New Heptosyltransferase Signature Sequence

PubMed Central

Merino, Susana; Knirel, Yuriy A.; Regué, Miguel; Tomás, Juan M.

2013-01-01

We experimentally identified the activities of six predicted heptosyltransferases in Actinobacillus pleuropneumoniae genome serotype 5b strain L20 and serotype 3 strain JL03. The initial identification was based on a bioinformatic analysis of the amino acid similarity between these putative heptosyltrasferases with others of known function from enteric bacteria and Aeromonas. The putative functions of all the Actinobacillus pleuropneumoniae heptosyltrasferases were determined by using surrogate LPS acceptor molecules from well-defined A. hydrophyla AH-3 and A. salmonicida A450 mutants. Our results show that heptosyltransferases APL_0981 and APJL_1001 are responsible for the transfer of the terminal outer core D-glycero-D-manno-heptose (D,D-Hep) residue although they are not currently included in the CAZY glycosyltransferase 9 family. The WahF heptosyltransferase group signature sequence [S(T/S)(GA)XXH] differs from the heptosyltransferases consensus signature sequence [D(TS)(GA)XXH], because of the substitution of D261 for S261, being unique. PMID:23383222

Development of two real-time polymerase chain reaction assays to detect Actinobacillus pleuropneumoniae serovars 1-9-11 and serovar 2.

PubMed

Marois-Créhan, Corinne; Lacouture, Sonia; Jacques, Mario; Fittipaldi, Nahuel; Kobisch, Marylène; Gottschalk, Marcelo

2014-01-01

Two real-time, or quantitative, polymerase chain reaction (qPCR) assays were developed to detect Actinobacillus pleuropneumoniae serovars 1-9-11 (highly related serovars with similar virulence potential) and serovar 2, respectively. The specificity of these assays was verified on a collection of 294 strains, which included all 16 reference A. pleuropneumoniae strains (including serovars 5a and 5b), 263 A. pleuropneumoniae field strains isolated between 1992 and 2009 in different countries, and 15 bacterial strains other than A. pleuropneumoniae. The detection levels of both qPCR tests were evaluated using 10-fold dilutions of chromosomal DNA from reference strains of A. pleuropneumoniae serovars 1 and 2, and the detection limit for both assays was 50 fg per assay. The analytical sensitivities of the qPCR tests were also estimated by using pure cultures and tonsils experimentally spiked with A. pleuropneumoniae. The detection threshold was 2.5 × 10(4) colony forming units (CFU)/ml and 2.9 × 10(5) CFU/0.1 g of tonsil, respectively, for both assays. These specific and sensitive tests can be used for the serotyping of A. pleuropneumoniae in diagnostic laboratories to control porcine pleuropneumonia.

Generation of transgenic corn-derived Actinobacillus pleuropneumoniae ApxIIA fused with the cholera toxin B subunit as a vaccine candidate

PubMed Central

Shin, Min-Kyoung; Jung, Myung Hwan; Lee, Won-Jung; Choi, Pil Son; Jang, Yong-Suk

2011-01-01

Corn, one of the most important forage crops worldwide, has proven to be a useful expression vehicle due to the availability of established transformation procedures for this well-studied plant. The exotoxin Apx, a major virulence factor, is recognized as a common antigen of Actinobacillus (A.) pleuropneumoniae, the causative agent of porcine pleuropneumonia. In this study, a cholera toxin B (CTB)-ApxIIA#5 fusion protein and full-size ApxIIA expressed in corn seed, as a subunit vaccine candidate, were observed to induce Apx-specific immune responses in mice. These results suggest that transgenic corn-derived ApxIIA and CTB-ApxIIA#5 proteins are potential vaccine candidates against A. pleuropneumoniae infection. PMID:22122907

A Unique Capsule Locus in the Newly Designated Actinobacillus pleuropneumoniae Serovar 16 and Development of a Diagnostic PCR Assay.

PubMed

Bossé, Janine T; Li, Yanwen; Sárközi, Rita; Gottschalk, Marcelo; Angen, Øystein; Nedbalcova, Katerina; Rycroft, Andrew N; Fodor, László; Langford, Paul R

2017-03-01

Actinobacillus pleuropneumoniae causes pleuropneumonia, an economically significant lung disease of pigs. Recently, isolates of A. pleuropneumoniae that were serologically distinct from the previously characterized 15 serovars were described, and a proposal was put forward that they comprised a new serovar, serovar 16. Here we used whole-genome sequencing of the proposed serovar 16 reference strain A-85/14 to confirm the presence of a unique capsular polysaccharide biosynthetic locus. For molecular diagnostics, primers were designed from the capsule locus of strain A-85/14, and a PCR was formulated that differentiated serovar 16 isolates from all 15 known serovars and other common respiratory pathogenic/commensal bacteria of pigs. Analysis of the capsule locus of strain A-85/14 combined with the previous serological data show the existence of a sixteenth serovar-designated serovar 16-of A. pleuropneumoniae . Copyright © 2017 Bossé et al.

Actinobacillus pleuropneumoniae genes expression in biofilms cultured under static conditions and in a drip-flow apparatus

PubMed Central

2013-01-01

Background Actinobacillus pleuropneumoniae is the Gram-negative bacterium responsible for porcine pleuropneumonia. This respiratory infection is highly contagious and characterized by high morbidity and mortality. The objectives of our study were to study the transcriptome of A. pleuropneumoniae biofilms at different stages and to develop a protocol to grow an A. pleuropneumoniae biofilm in a drip-flow apparatus. This biofilm reactor is a system with an air-liquid interface modeling lung-like environment. Bacteria attached to a surface (biofilm) and free floating bacteria (plankton) were harvested for RNA isolation. Labelled cDNA was hybridized to a microarray to compare the expression profiles of planktonic cells and biofilm cells. Results It was observed that 47 genes were differentially expressed (22 up, 25 down) in a 4 h-static growing/maturing biofilm and 117 genes were differentially expressed (49 up, 68 down) in a 6h-static dispersing biofilm. The transcriptomes of a 4 h biofilm and a 6 h biofilm were also compared and 456 genes (235 up, 221 down) were identified as differently expressed. Among the genes identified in the 4 h vs 6h biofilm experiment, several regulators of stress response were down-regulated and energy metabolism associated genes were up-regulated. Biofilm bacteria cultured using the drip-flow apparatus differentially expressed 161 genes (68 up, 93 down) compared to the effluent bacteria. Cross-referencing of differentially transcribed genes in the different assays revealed that drip-flow biofilms shared few differentially expressed genes with static biofilms (4 h or 6 h) but shared several differentially expressed genes with natural or experimental infections in pigs. Conclusion The formation of a static biofilm by A. pleuropneumoniae strain S4074 is a rapid process and transcriptional analysis indicated that dispersal observed at 6 h is driven by nutritional stresses. Furthermore, A. pleuropneumoniae can form a biofilm under low

Assessment of the efficacy of tilmicosin phosphate to eliminate Actinobacillus pleuropneumoniae from carrier pigs

PubMed Central

2005-01-01

Abstract The aim of this study was to evaluate the efficacy of in-feed medication with tilmicosin phosphate in order to eliminate or reduce the carriage of Actinobacillus pleuropneumoniae in the tonsils of carrier pigs. Two groups of 6 carrier animals received either a non-medicated feed (control group) or feed medicated with 400 ppm of tilmicosin phosphate (treated group) for 30 d. Three sentinel pigs were then introduced in each group and left for 29 d. The presence of A. pleuropneumoniae in tonsils was monitored using several techniques, including polymerase chain reaction (PCR). At the end of the treatment all of the control animals, but only 1 treated pig, were positive by PCR from tonsillar surface material. However, at necropsy, all control and most treated animals, as well as 1 sentinel animal, in both groups were positive by PCR from whole tonsils. In conclusion, under the experimental conditions, in-feed treatment with 400 ppm of tilmicosin phosphate significantly reduced the presence of A. pleuropneumoniae on the surface of tonsils but was unable to completely eliminate the organism from deeper tonsillar tissues and to prevent bacterial shedding by carrier animals. PMID:15971680

Assessment of the efficacy of tilmicosin phosphate to eliminate Actinobacillus pleuropneumoniae from carrier pigs.

PubMed

Fittipaldi, N; Klopfenstein, C; Gottschalk, M; Broes, A; Paradis, M A; Dick, C P

2005-04-01

The aim of this study was to evaluate the efficacy of in-feed medication with tilmicosin phosphate in order to eliminate or reduce the carriage of Actinobacillus pleuropneumoniae in the tonsils of carrier pigs. Two groups of 6 carrier animals received either a non-medicated feed (control group) or feed medicated with 400 ppm of tilmicosin phosphate (treated group) for 30 d. Three sentinel pigs were then introduced in each group and left for 29 d. The presence of A. pleuropneumoniae in tonsils was monitored using several techniques, including polymerase chain reaction (PCR). At the end of the treatment all of the control animals, but only 1 treated pig, were positive by PCR from tonsillar surface material. However, at necropsy, all control and most treated animals, as well as 1 sentinel animal, in both groups were positive by PCR from whole tonsils. In conclusion, under the experimental conditions, in-feed treatment with 400 ppm of tilmicosin phosphate significantly reduced the presence of A. pleuropneumoniae on the surface of tonsils but was unable to completely eliminate the organism from deeper tonsillar tissues and to prevent bacterial shedding by carrier animals.

Pyridoxal phosphate synthases PdxS/PdxT are required for Actinobacillus pleuropneumoniae viability, stress tolerance and virulence.

PubMed

Xie, Fang; Li, Gang; Wang, Yalei; Zhang, Yanhe; Zhou, Long; Wang, Chengcheng; Liu, Shuanghong; Liu, Siguo; Wang, Chunlai

2017-01-01

Pyridoxal 5'-phosphate (PLP) is an essential cofactor for numerous enzymes involved in a diversity of cellular processes in living organisms. Previous analysis of the Actinobacillus pleuropneumoniae S-8 genome sequence revealed the presence of pdxS and pdxT genes, which are implicated in deoxyxylulose 5-phosphate (DXP)-independent pathway of PLP biosynthesis; however, little is known about their roles in A. pleuropneumoniae pathogenicity. Our data demonstrated that A. pleuropneumoniae could synthesize PLP by PdxS and PdxT enzymes. Disruption of the pdxS and pdxT genes rendered the pathogen auxotrophic for PLP, and the defective growth as a result of these mutants was chemically compensated by the addition of PLP, suggesting the importance of PLP production for A. pleuropneumoniae growth and viability. Additionally, the pdxS and pdxT deletion mutants displayed morphological defects as indicated by irregular and aberrant shapes in the absence of PLP. The reduced growth of the pdxS and pdxT deletion mutants under osmotic and oxidative stress conditions suggests that the PLP synthases PdxS/PdxT are associated with the stress tolerance of A. pleuropneumoniae. Furthermore, disruption of the PLP biosynthesis pathway led to reduced colonization and attenuated virulence of A. pleuropneumoniae in the BALB/c mouse model. The data presented in this study reveal the critical role of PLP synthases PdxS/PdxT in viability, stress tolerance, and virulence of A. pleuropneumoniae.

Macrophages largely contribute to heterologous anti-Propionibacterium acnes antibody-mediated protection from Actinobacillus pleuropneumoniae infection in mice.

PubMed

Ma, Qiuyue; Sun, Changjiang; Yang, Feng; Wang, Lei; Qin, Wanhai; Xia, Xiaojing; Feng, Xin; Du, Chongtao; Gu, Jingmin; Han, Wenyu; Lei, Liancheng

2015-03-01

Actinobacillus pleuropneumoniae is the causative agent of acute and chronic pleuropneumonia. Propionibacterium acnes is a facultative anaerobic gram-positive corynebacterium. We have previously found that anti-P. acnes antibodies can prevent A. pleuropneumoniae infections in mice. To investigate the role of macrophages in this process, affinity-purified anti-P. acnes IgG and anti-A. pleuropneumoniae IgG were used in opsonophagocytosis assays. Additionally, the efficacy of passive immunization with P. acnes serum against A. pleuropneumoniae was tested in macrophage-depleted mice. It was found that anti-P. acnes IgG had an effect similar to that of anti-A. pleuropneumoniae IgG (P > 0.05), which significantly promotes phagocytosis of A. pleuropneumoniae by macrophages (P < 0.01). It was also demonstrated that, after passive immunization with anti-P. acnes serum, macrophage-replete mice had the highest survival rate (90%), whereas the survival rate of macrophage-depleted mice was only 40% (P < 0.05). However, macrophage-depleted mice that had been passively immunized with naïve serum had the lowest survival rate (20%), this rate being lower than that of macrophage-replete mice that had been passively immunized with naïve serum. Overall, anti-P. acnes antibodies did not prevent A. pleuropneumoniae infection under conditions of macrophage depletion (P > 0.05). Furthermore, in mice that had been passively immunized with anti-P. acnes serum, macrophage depletion resulted in a greater A. pleuropneumoniae burden and more severe pathological features of pneumonia in lung tissues than occurred in macrophage-replete mice. It was concluded that macrophages are essential for the process by which anti-P. acnes antibody prevents A. pleuropneumoniae infection in mice. © 2015 The Societies and Wiley Publishing Asia Pty Ltd.

Thymol kills bacteria, reduces biofilm formation, and protects mice against a fatal infection of Actinobacillus pleuropneumoniae strain L20.

PubMed

Wang, Lei; Zhao, Xueqin; Zhu, Chunling; Xia, Xiaojing; Qin, Wanhai; Li, Mei; Wang, Tongzhao; Chen, Shijun; Xu, Yanzhao; Hang, Bolin; Sun, Yawei; Jiang, Jinqing; Richard, Langford Paul; Lei, Liancheng; Zhang, Gaiping; Hu, Jianhe

2017-05-01

Actinobacillus pleuropneumoniae is the causative agent of the highly contagious and deadly respiratory infection porcine pleuropneumonia, resulting in serious losses to the pig industry worldwide. Alternative to antibiotics are urgently needed due to the serious increase in antimicrobial resistance. Thymol is a monoterpene phenol and efficiently kills a variety of bacteria. This study found that thymol has strong bactericidal effects on the A. pleuropneumoniae 5b serotype strain, an epidemic strain in China. Sterilization occurred rapidly, and the minimum inhibitory concentration (MIC) is 31.25μg/mL; the A. pleuropneumoniae density was reduced 1000 times within 10min following treatment with 1 MIC. Transmission electron microscopy (TEM) analysis revealed that thymol could rapidly disrupt the cell walls and cell membranes of A. pleuropneumoniae, causing leakage of cell contents and cell death. In addition, treatment with thymol at 0.5 MIC significantly reduced the biofilm formation of A. pleuropneumoniae. Quantitative RT-PCR results indicated that thymol treatment significantly increased the expression of the virulence genes purC, tbpB1 and clpP and down-regulated ApxI, ApxII and Apa1 expression in A. pleuropneumoniae. Therapeutic analysis of a murine model showed that thymol (20mg/kg) protected mice from a lethal dose of A. pleuropneumoniae, attenuated lung pathological lesions. This study is the first to report the use of thymol to treat A. pleuropneumoniae infection, establishing a foundation for the development of new antimicrobials. Copyright © 2017 Elsevier B.V. All rights reserved.

A Transcriptome Map of Actinobacillus pleuropneumoniae at Single-Nucleotide Resolution Using Deep RNA-Seq

PubMed Central

Su, Zhipeng; Zhu, Jiawen; Xu, Zhuofei; Xiao, Ran; Zhou, Rui; Li, Lu; Chen, Huanchun

2016-01-01

Actinobacillus pleuropneumoniae is the pathogen of porcine contagious pleuropneumoniae, a highly contagious respiratory disease of swine. Although the genome of A. pleuropneumoniae was sequenced several years ago, limited information is available on the genome-wide transcriptional analysis to accurately annotate the gene structures and regulatory elements. High-throughput RNA sequencing (RNA-seq) has been applied to study the transcriptional landscape of bacteria, which can efficiently and accurately identify gene expression regions and unknown transcriptional units, especially small non-coding RNAs (sRNAs), UTRs and regulatory regions. The aim of this study is to comprehensively analyze the transcriptome of A. pleuropneumoniae by RNA-seq in order to improve the existing genome annotation and promote our understanding of A. pleuropneumoniae gene structures and RNA-based regulation. In this study, we utilized RNA-seq to construct a single nucleotide resolution transcriptome map of A. pleuropneumoniae. More than 3.8 million high-quality reads (average length ~90 bp) from a cDNA library were generated and aligned to the reference genome. We identified 32 open reading frames encoding novel proteins that were mis-annotated in the previous genome annotations. The start sites for 35 genes based on the current genome annotation were corrected. Furthermore, 51 sRNAs in the A. pleuropneumoniae genome were discovered, of which 40 sRNAs were never reported in previous studies. The transcriptome map also enabled visualization of 5'- and 3'-UTR regions, in which contained 11 sRNAs. In addition, 351 operons covering 1230 genes throughout the whole genome were identified. The RNA-Seq based transcriptome map validated annotated genes and corrected annotations of open reading frames in the genome, and led to the identification of many functional elements (e.g. regions encoding novel proteins, non-coding sRNAs and operon structures). The transcriptional units described in this study

Identification of proteins of Propionibacterium acnes for use as vaccine candidates to prevent infection by the pig pathogen Actinobacillus pleuropneumoniae.

PubMed

Li, Linxi; Sun, Changjiang; Yang, Feng; Yang, Shuxin; Feng, Xin; Gu, Jingmin; Han, Wenyu; Langford, Paul R; Lei, Liancheng

2013-10-25

Actinobacillus pleuropneumoniae is the causative agent of acute and chronic pleuroneumonia that is responsible for substantial morbidity and mortality in the pig industry. New improved vaccines that can protect against all serotypes and prevent colonization are required. In a previous study we showed that whole cells of Propionibacterium acnes protected pigs from A. pleuropneumoniae serotype 1 and 5 and, therefore, the basis for a promising heterologous vaccine. The aim of this study was to identify those protein antigens of P. acnes responsible for protection against A. pleuropneumoniae infection. Six P. acnes protein antigens that were recognized by sera raised against A. pleuropneumoniae were identified by 2-DE and immunoblotting. Recombinant versions of all P. acnes proteins gave partial protection (10-80%) against A. pleuropneumoniae serotype 1 and/or 5 infection in a mouse challenge model. The best protection (80% serotype 1; 60% serotype 5) was obtained using recombinant P. acnes single-stranded DNA-binding protein. In part, protection against A. pleuropneumoniae infection may be mediated by small peptide sequences present in P. acnes single-stranded DNA-binding protein that are cross-reactive with those present in the A. pleuropneumoniae-specific RTX toxin ApxIV and the zinc-binding protein ZnuA. The results suggest that P. acnes may be a useful vaccine to protect against different serotypes of A. pleuropneumoniae. Copyright © 2013 Elsevier Ltd. All rights reserved.

Surface Polysaccharide Mutants Reveal that Absence of O Antigen Reduces Biofilm Formation of Actinobacillus pleuropneumoniae

PubMed Central

Hathroubi, S.; Hancock, M. A.; Langford, P. R.; Tremblay, Y. D. N.; Labrie, J.

2015-01-01

Actinobacillus pleuropneumoniae is a Gram-negative bacterium belonging to the Pasteurellaceae family and the causative agent of porcine pleuropneumonia, a highly contagious lung disease causing important economic losses. Surface polysaccharides, including lipopolysaccharides (LPS) and capsular polysaccharides (CPS), are implicated in the adhesion and virulence of A. pleuropneumoniae, but their role in biofilm formation is still unclear. In this study, we investigated the requirement for these surface polysaccharides in biofilm formation by A. pleuropneumoniae serotype 1. Well-characterized mutants were used: an O-antigen LPS mutant, a truncated core LPS mutant with an intact O antigen, a capsule mutant, and a poly-N-acetylglucosamine (PGA) mutant. We compared the amount of biofilm produced by the parental strain and the isogenic mutants using static and dynamic systems. Compared to the findings for the biofilm of the parental or other strains, the biofilm of the O antigen and the PGA mutants was dramatically reduced, and it had less cell-associated PGA. Real-time PCR analyses revealed a significant reduction in the level of pgaA, cpxR, and cpxA mRNA in the biofilm cells of the O-antigen mutant compared to that in the biofilm cells of the parental strain. Specific binding between PGA and LPS was consistently detected by surface plasmon resonance, but the lack of O antigen did not abolish these interactions. In conclusion, the absence of the O antigen reduces the ability of A. pleuropneumoniae to form a biofilm, and this is associated with the reduced expression and production of PGA. PMID:26483403

Antimicrobial resistance genes in Actinobacillus pleuropneumoniae, Haemophilus parasuis and Pasteurella multocida isolated from Australian pigs.

PubMed

Dayao, Dae; Gibson, J S; Blackall, P J; Turni, C

2016-07-01

To identify genes associated with the observed antimicrobial resistance in Actinobacillus pleuropneumoniae, Haemophilus parasuis and Pasteurella multocida isolated from Australian pigs. Isolates with known phenotypic resistance to β-lactams, macrolides and tetracycline were screened for the presence of antimicrobial resistance genes. A total of 68 A. pleuropneumoniae, 62 H. parasuis and 20 P. multocida isolates exhibiting phenotypic antimicrobial resistance (A. pleuropneumoniae and P. multocida) or elevated minimal inhibitory concentrations (MICs) (H. parasuis) to any of the following antimicrobial agents - ampicillin, erythromycin, penicillin, tetracycline, tilmicosin and tulathromycin - were screened for a total of 19 associated antimicrobial resistance genes (ARGs) by PCR. The gene bla ROB-1 was found in all ampicillin- and penicillin-resistant isolates, but none harboured the bla TEM-1 gene. The tetB gene was found in 76% (74/97) of tetracycline-resistant isolates, 49/53 A. pleuropneumoniae, 17/30 H. parasuis and 8/14 P. multocida. One A. pleuropneumoniae isolate harboured the tetH gene, but none of the 97 isolates had tetA, tetC, tetD, tetE, tetL, tetM or tetO. A total of 92 isolates were screened for the presence of macrolide resistance genes. None was found to have ermA, ermB, ermC, erm42, mphE, mefA, msrA or msrE. The current study has provided a genetic explanation for the resistance or elevated MIC of the majority of isolates of Australian porcine respiratory pathogens to ampicillin, penicillin and tetracycline. However, the macrolide resistance observed by phenotypic testing remains genetically unexplained and further studies are required. © 2016 Australian Veterinary Association.

Serotyping reanalysis of unserotypable Actinobacillus pleuropneumoniae isolates by agar gel diffusion test.

PubMed

Morioka, Ayako; Shimazaki, Yoko; Uchiyama, Mariko; Suzuki, Shoko

2016-05-03

We observed increasing unserotypable (UT) Actinobacillus pleuropneumoniae isolates using agar gel diffusion (AGD) test. To reanalyze their serovar, we performed rapid slide agglutination (RSA) test and multiplex PCR for 47 UT isolates. Of these, 25 were serovar 1 (UT-serovar 1), 20 were serovar 2 (UT-serovar 2) and 2 were serovar 15 (UT-serovar 15). We examined serotyping antigen extraction temperature to determine heat influence. UT-serovar 1 and 15 were influenced by heat, because their precipitation lines were observed in the case of low antigen extraction temperature. To investigate the relationship between antigenicity and genotype, we performed pulsed-field gel electrophoresis (PFGE) analysis using UT-serovar 2 and 15. The predominant PFGE pattern of UT-serovar 2 was identical to that of serovar 2.

Identification of the Actinobacillus pleuropneumoniae Leucine-Responsive Regulatory Protein and Its Involvement in the Regulation of In Vivo-Induced Genes▿

PubMed Central

Wagner, Trevor K.; Mulks, Martha H.

2007-01-01

Actinobacillus pleuropneumoniae is a gram-negative bacterial pathogen that causes a severe hemorrhagic pneumonia in swine. We have previously shown that the limitation of branched-chain amino acids (BCAAs) is a cue that induces the expression of a subset of A. pleuropneumoniae genes identified as specifically induced during infection of the natural host animal by using an in vivo expression technology screen. Leucine-responsive regulatory protein (Lrp) is a global regulator and has been shown in Escherichia coli to regulate many genes, including genes involved in BCAA biosynthesis. We hypothesized that A. pleuropneumoniae contains a regulator similar to Lrp and that this protein is involved in the regulation of a subset of genes important during infection and recently shown to have increased expression in the absence of BCAAs. We report the identification of an A. pleuropneumoniae serotype 1 gene encoding a protein with similarity to amino acid sequence and functional domains of other reported Lrp proteins. We further show that purified A. pleuropneumoniae His6-Lrp binds in vitro to the A. pleuropneumoniae promoter regions for ilvI, antisense cps1AB, lrp, and nqr. A genetically defined A. pleuropneumoniae lrp mutant was constructed using an allelic replacement and sucrose counterselection method. Analysis of expression from the ilvI and antisense cps1AB promoters in wild-type, lrp mutant, and complemented lrp mutant strains indicated that Lrp is required for induction of expression of ilvI under BCAA limitation. PMID:17060463

Evaluation of a multiplex PCR to identify and serotype Actinobacillus pleuropneumoniae serovars 1, 5, 7, 12 and 15.

PubMed

Turni, C; Singh, R; Schembri, M A; Blackall, P J

2014-10-01

The aim of this study was to validate a multiplex PCR for the species identification and serotyping of Actinobacillus pleuropneumoniae serovars 1, 5, 7, 12 and 15. All 15 reference strains and 411 field isolates (394 from Australia, 11 from Indonesia, five from Mexico and one from New Zealand) of A. pleuropneumoniae were tested with the multiplex PCR. The specificity of this multiplex PCR was validated on 26 non-A. pleuropneumoniae species. The multiplex PCR gave the expected results with all 15 serovar reference strains and agreed with conventional serotyping for all field isolates from serovars 1 (n = 46), 5 (n = 81), 7 (n = 80), 12 (n = 16) and serovar 15 (n = 117). In addition, a species-specific product was amplified in the multiplex PCR with all 411 A. pleuropneumoniae field isolates. Of 25 nontypeable field isolates only two did not yield a serovar-specific band in the multiplex PCR. This multiplex PCR for serovars 1, 5, 7, 12 and 15 is species specific and capable of serotyping isolates from diverse locations. Significance and impact of the study: A multiplex PCR that can recognize serovars 1, 5, 7, 12 and 15 of A. pleuropneumoniae was developed and validated. This novel diagnostic tool will enable frontline laboratories to provide key information (the serovar) to guide targeted prevention and control programmes for porcine pleuropneumonia, a serious economic disease of pigs. The previous technology, traditional serotyping, is typically provided by specialized reference laboratories, limiting the capacity to respond to this key disease. © 2014 The Society for Applied Microbiology.

Identification of dfrA14 in two distinct plasmids conferring trimethoprim resistance in Actinobacillus pleuropneumoniae

PubMed Central

Bossé, Janine T.; Li, Yanwen; Walker, Stephanie; Atherton, Tom; Fernandez Crespo, Roberto; Williamson, Susanna M.; Rogers, Jon; Chaudhuri, Roy R.; Weinert, Lucy A.; Oshota, Olusegun; Holden, Matt T. G.; Maskell, Duncan J.; Tucker, Alexander W.; Wren, Brendan W.; Rycroft, Andrew N.; Langford, Paul R.

2015-01-01

Objectives The objective of this study was to determine the distribution and genetic basis of trimethoprim resistance in Actinobacillus pleuropneumoniae isolates from pigs in England. Methods Clinical isolates collected between 1998 and 2011 were tested for resistance to trimethoprim and sulphonamide. The genetic basis of trimethoprim resistance was determined by shotgun WGS analysis and the subsequent isolation and sequencing of plasmids. Results A total of 16 (out of 106) A. pleuropneumoniae isolates were resistant to both trimethoprim (MIC >32 mg/L) and sulfisoxazole (MIC ≥256 mg/L), and a further 32 were resistant only to sulfisoxazole (MIC ≥256 mg/L). Genome sequence data for the trimethoprim-resistant isolates revealed the presence of the dfrA14 dihydrofolate reductase gene. The distribution of plasmid sequences in multiple contigs suggested the presence of two distinct dfrA14-containing plasmids in different isolates, which was confirmed by plasmid isolation and sequencing. Both plasmids encoded mobilization genes, the sulphonamide resistance gene sul2, as well as dfrA14 inserted into strA, a streptomycin-resistance-associated gene, although the gene order differed between the two plasmids. One of the plasmids further encoded the strB streptomycin-resistance-associated gene. Conclusions This is the first description of mobilizable plasmids conferring trimethoprim resistance in A. pleuropneumoniae and, to our knowledge, the first report of dfrA14 in any member of the Pasteurellaceae. The identification of dfrA14 conferring trimethoprim resistance in A. pleuropneumoniae isolates will facilitate PCR screens for resistance to this important antimicrobial. PMID:25957382

Apa is a trimeric autotransporter adhesin of Actinobacillus pleuropneumoniae responsible for autoagglutination and host cell adherence.

PubMed

Xiao, Longwen; Zhou, Liang; Sun, Changjiang; Feng, Xin; Du, ChongTao; Gao, Yu; Ji, Qun; Yang, Shuxin; Wang, Yu; Han, Wenyu; Langford, P R; Lei, Liancheng

2012-10-01

Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia, and adherence to host cells is a key step in the pathogenic process. Although trimeric autotransporter adhesins (TAAs) were identified in many pathogenic bacteria in recent years, none in A. pleuropneumoniae have been characterized. In this study, we identified a TAA from A. pleuropneumoniae, Apa, and characterized the contribution of its amino acid residues to the adhesion process. Sequence analysis of the C-terminal amino acid residues of Apa revealed the presence of a putative translocator domain and six conserved HsfBD1-like or HsfBD2-like binding domains. Western blot analysis revealed that the 126 C-terminal amino acids of Apa could form trimeric molecules. By confocal laser scanning microscopy, one of these six domains (ApaBD3) was determined to mediate adherence to epithelial cells. Adherence assays and adherence inhibition assays using a recombinant E. coli- ApaBD3 strain which expressed ApaBD3 on the surface of E. coli confirmed that this domain was responsible for the adhesion activity. Moreover, cellular enzyme-linked immunosorbent assays demonstrated that ApaBD3 mediated high-level adherence to epithelial cell lines. Intriguingly, autoagglutination was observed with the E. coli- ApaBD3 strain, and this phenomenon was dependent upon the association of the expressed ApaBD3 with the C-terminal translocator domain. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Potency of marbofloxacin for pig pneumonia pathogens Actinobacillus pleuropneumoniae and Pasteurella multocida: Comparison of growth media.

PubMed

Dorey, L; Hobson, S; Lees, P

2017-04-01

Pharmacodynamic properties of marbofloxacin were established for six isolates each of the pig respiratory tract pathogens, Actinobacillus pleuropneumoniae and Pasteurella multocida. Three in vitro indices of potency were determined; Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Mutant Prevention Concentration (MPC). For MIC determination Clinical Laboratory Standards Institute guidelines were modified in three respects: (1) comparison was made between two growth media, an artificial broth and pig serum; (2) a high inoculum count was used to simulate heavy clinical bacteriological loads; and (3) five overlapping sets of two-fold dilutions were used to improve accuracy of determinations. Similar methods were used for MBC and MPC estimations. MIC and MPC serum:broth ratios for A. pleuropneumoniae were 0.79:1 and 0.99:1, respectively, and corresponding values for P. multocida were 1.12:1 and 1.32:1. Serum protein binding of marbofloxacin was 49%, so that fraction unbound (fu) serum MIC values were significantly lower than those predicted by correction for protein binding; fu serum:broth MIC ratios were 0.40:1 (A. pleuropneumoniae) and 0.50:1 (P. multocida). For broth, MPC:MIC ratios were 13.7:1 (A. pleuropneumoniae) and 14.2:1 (P. multocida). Corresponding ratios for serum were similar, 17.2:1 and 18.8:1, respectively. It is suggested that, for dose prediction purposes, serum data might be preferable to potency indices measured in broths. Copyright © 2016 Elsevier Ltd. All rights reserved.

B cell cross-epitope of Propionibacterium acnes and Actinobacillus pleuropneumonia selected by phage display library can efficiently protect from Actinobacillus pleuropneumonia infection.

PubMed

Liu, Jianfang; Ma, Qiuyue; Yang, Feng; Zhu, Rining; Gu, Jingmin; Sun, Changjiang; Feng, Xin; Du, Chongtao; Langford, Paul R; Han, Wenyu; Yang, Junling; Lei, Liancheng

2017-06-01

Contagious porcine pleuropneumonia (CPP), caused by Actinobacillus pleuropneumoniae (APP), is a highly transmissible and fatal respiratory illness that causes tremendous economic losses for the pig breeding industry worldwide. Propionibacterium acnes (PA) has a strong cross-reaction with anti-APP1 and anti-APP5 serum and can efficiently prevent APP infection, which was fortuitously found in researching the differential gene between the different APP serotypes. There seems to be some natural cross-protection between PA and APP. To identify the common epitope, the phage display library of a PA whole genome was constructed, whose size is 10 5 . The DNA sequence of the positive clone was determined after three rounds of biopanning, and ten common protein types were identified and the epitope was predicted by computer software. Six peptide epitopes were selected and synthesized for further analysis. Among these epitopes, Ba1, Bb5 and C1 could bind to anti-PA serum and anti-APP1 serum and vice versa. Furthermore, the IgG and IL-4 levels and CD4 + /CD8 + T cell ratios in the Ba1, Bb5 and C1 groups were significantly higher than that in the control group, indicating that the epitopes could trigger an immune response, which was mainly humoral immunity. Moreover, Ba1 and Bb5 equally protected 80% of mice from a fatal dose of APP1 infection compared with the control group. Mice could resist APP1 and APP5 challenge after being treated with the combination of Ba1 and Bb5, with survival rates of 80% and 90%, respectively. These findings suggest that the PA epitope confers antigenicity and can heterologously resist to the APP infection. This finding provides a novel strategy for preventing APP infection. Copyright © 2017 Elsevier B.V. All rights reserved.

Serotyping reanalysis of unserotypable Actinobacillus pleuropneumoniae isolates by agar gel diffusion test

PubMed Central

MORIOKA, Ayako; SHIMAZAKI, Yoko; UCHIYAMA, Mariko; SUZUKI, Shoko

2016-01-01

We observed increasing unserotypable (UT) Actinobacillus pleuropneumoniae isolates using agar gel diffusion (AGD) test. To reanalyze their serovar, we performed rapid slide agglutination (RSA) test and multiplex PCR for 47 UT isolates. Of these, 25 were serovar 1 (UT-serovar 1), 20 were serovar 2 (UT-serovar 2) and 2 were serovar 15 (UT-serovar 15). We examined serotyping antigen extraction temperature to determine heat influence. UT-serovar 1 and 15 were influenced by heat, because their precipitation lines were observed in the case of low antigen extraction temperature. To investigate the relationship between antigenicity and genotype, we performed pulsed-field gel electrophoresis (PFGE) analysis using UT-serovar 2 and 15. The predominant PFGE pattern of UT-serovar 2 was identical to that of serovar 2. PMID:26726101

Characterization of bifunctional L-glutathione synthetases from Actinobacillus pleuropneumoniae and Actinobacillus succinogenes for efficient glutathione biosynthesis.

PubMed

Yang, Jianhua; Li, Wei; Wang, Dezheng; Wu, Hui; Li, Zhimin; Ye, Qin

2016-07-01

Glutathione (GSH), an important bioactive substance, is widely applied in pharmaceutical and food industries. In this work, two bifunctional L-glutathione synthetases (GshF) from Actinobacillus pleuropneumoniae (GshFAp) and Actinobacillus succinogenes (GshFAs) were successfully expressed in Escherichia coli BL-21(DE3). Similar to the GshF from Streptococcus thermophilus (GshFSt), GshFAp and GshFAs can be applied for high titer GSH production because they are less sensitive to end-product inhibition (Ki values 33 and 43 mM, respectively). The active catalytic forms of GshFAs and GshFAp are dimers, consistent with those of GshFPm (GshF from Pasteurella multocida) and GshFSa (GshF from Streptococcus agalactiae), but are different from GshFSt (GshF from S. thermophilus) which is an active monomer. The analysis of the protein sequences and three dimensional structures of GshFs suggested that the binding sites of GshFs for substrates, L-cysteine, L-glutamate, γ-glutamylcysteine, adenosine-triphosphate, and glycine are highly conserved with only very few differences. With sufficient supply of the precursors, the recombinant strains BL-21(DE3)/pET28a-gshFas and BL-21(DE3)/pET28a-gshFap were able to produce 36.6 and 34.1 mM GSH, with the molar yield of 0.92 and 0.85 mol/mol, respectively, based on the added L-cysteine. The results showed that GshFAp and GshFAs are potentially good candidates for industrial GSH production.

Differential gene expression profiling of Actinobacillus pleuropneumoniae during induction of primary alveolar macrophage apoptosis in piglets.

PubMed

Wang, Lei; Qin, Wanhai; Ruidong, Zhai; Liu, Shiting; Zhang, Hu; Sun, Changjiang; Feng, Xin; Gu, Jingmin; Du, Chongtao; Han, Wenyu; Langford, P R; Lei, Liancheng

2015-01-01

Actinobacillus pleuropneumoniae (A. pleuropneumoniae) is the causative agent of porcine pleuropneumonia, a disease that causes serious problems for the swine industry. Successful infection by this bacterium requires breaking the first line of defence in the lungs, the primary alveolar macrophages (PAMs). Therefore, exploring A. pleuropneumoniae-PAM interactions will provide vital groundwork for the scientific control of this infectious disease, which has been little studied up to now. In this work, PAMs were isolated from piglets and co-incubated with A. pleuropneumoniae serovar 5b strain L20 in vitro, and their interaction, PAM cell death, and differential gene expression of A. pleuropneumoniae in response to PAM cell death were observed and analysed using confocal microscopy, electron microscopy, RT-PCR, Western blot, flow cytometry and the use of a gene expression profile chip. A. pleuropneumoniae quickly adhered to and invaded PAMs, inducing apoptosis, which was confirmed using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The highest percentage of apoptosis in cells was confirmed using flow cytometry when the cells were infected at a multiplicity of infection (MOI) of 10 and incubated for 5 h, with higher expression of activated caspase-3 as measured by Western blot. Using microarray gene chips with 2868 probes containing nearly all of the genomic sequence of A. pleuropneumoniae serotype 5b strain L20, a total of 185 bacterial genes were found to be differentially expressed (including 92 up-regulated and 93 down-regulated genes) and involved in the process of apoptosis, as compared with the expression of control bacteria cultured without PAMs in BHI medium (mean expression ratios >1.5-fold, p < 0.05). The up-regulated genes are involved in energy metabolism, gene transcription and translation, virulence related gene such as LPS, Trimeric Autotransporter Adhesin, RTX and similar genes. The down-regulated genes are

Attenuated Actinobacillus pleuropneumoniae double-deletion mutant S-8∆clpP/apxIIC confers protection against homologous or heterologous strain challenge.

PubMed

Xie, Fang; Li, Gang; Zhou, Long; Zhang, Yanhe; Cui, Ning; Liu, Siguo; Wang, Chunlai

2017-01-06

Actinobacillus pleuropneumoniae is the etiological agent of porcine pleuropneumonia, which leads to large economic losses to the swine industry worldwide. In this study, S-8△clpP△apxIIC, a double-deletion mutant of A. pleuropneumoniae was constructed, and its safety and protective efficacy were evaluated in pigs. The S-8△clpP△apxIIC mutant exhibited attenuated virulence in a murine (BALB/c) model, and caused no detrimental effects on pigs even at a dose of up to 1.0 × 10 9  CFU. Furthermore, the S-8△clpP△apxIIC mutant was able to induce a strong immune response in pigs, which included high levels of IgG1 and IgG2, stimulated gamma interferon (IFN-γ), interleukin 12 (IL-12), and interleukin 4 (IL-4) production, and conferred effective protection against the lethal challenge with A. pleuropneumoniae serovars 7 or 5a. The pigs in the S-8△clpP△apxIIC immunized groups have no lesions and reduced bacterial loads in the lung tissue after challenge. The data obtained in this study suggest that the S-8△clpP△apxIIC mutant can serve as a highly immunogenic and potential live attenuated vaccine candidate against A. pleuropneumoniae infection.

Identification of dfrA14 in two distinct plasmids conferring trimethoprim resistance in Actinobacillus pleuropneumoniae.

PubMed

Bossé, Janine T; Li, Yanwen; Walker, Stephanie; Atherton, Tom; Fernandez Crespo, Roberto; Williamson, Susanna M; Rogers, Jon; Chaudhuri, Roy R; Weinert, Lucy A; Oshota, Olusegun; Holden, Matt T G; Maskell, Duncan J; Tucker, Alexander W; Wren, Brendan W; Rycroft, Andrew N; Langford, Paul R

2015-08-01

The objective of this study was to determine the distribution and genetic basis of trimethoprim resistance in Actinobacillus pleuropneumoniae isolates from pigs in England. Clinical isolates collected between 1998 and 2011 were tested for resistance to trimethoprim and sulphonamide. The genetic basis of trimethoprim resistance was determined by shotgun WGS analysis and the subsequent isolation and sequencing of plasmids. A total of 16 (out of 106) A. pleuropneumoniae isolates were resistant to both trimethoprim (MIC >32 mg/L) and sulfisoxazole (MIC ≥256 mg/L), and a further 32 were resistant only to sulfisoxazole (MIC ≥256 mg/L). Genome sequence data for the trimethoprim-resistant isolates revealed the presence of the dfrA14 dihydrofolate reductase gene. The distribution of plasmid sequences in multiple contigs suggested the presence of two distinct dfrA14-containing plasmids in different isolates, which was confirmed by plasmid isolation and sequencing. Both plasmids encoded mobilization genes, the sulphonamide resistance gene sul2, as well as dfrA14 inserted into strA, a streptomycin-resistance-associated gene, although the gene order differed between the two plasmids. One of the plasmids further encoded the strB streptomycin-resistance-associated gene. This is the first description of mobilizable plasmids conferring trimethoprim resistance in A. pleuropneumoniae and, to our knowledge, the first report of dfrA14 in any member of the Pasteurellaceae. The identification of dfrA14 conferring trimethoprim resistance in A. pleuropneumoniae isolates will facilitate PCR screens for resistance to this important antimicrobial. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.

Simulation study of the mechanisms underlying outbreaks of clinical disease caused by Actinobacillus pleuropneumoniae in finishing pigs.

PubMed

Klinkenberg, D; Tobias, T J; Bouma, A; van Leengoed, L A M G; Stegeman, J A

2014-10-01

Actinobacillus pleuropneumoniae is a major cause of respiratory disease in pigs. Many farms are endemically infected without apparent disease, but occasionally severe outbreaks of pleuropneumonia occur. To prevent and control these outbreaks without antibiotics, the underlying mechanisms of these outbreaks need to be understood. Outbreaks are probably initiated by a trigger (common risk factor) changing the host-pathogen interaction, but it is unclear whether this trigger causes all cases directly (trigger mechanism), or whether the first case starts a transmission chain inducing disease in the infected contacts (transmission mechanism). The aim of this study was to identify conditions under which these mechanisms could cause A. pleuropneumoniae outbreaks, and to assess means for prevention and control. Outbreaks were first characterised by data from a literature review, defining an average outbreak at 12 weeks of age, affecting 50% of animals within 4 days. Simple mathematical models describing the two mechanisms can reproduce average outbreaks, with two observations supporting the trigger mechanism: (1) disease should be transmitted 50 times faster than supported by literature if there is a transmission chain; and (2) the trigger mechanism is consistent with the absence of reported outbreaks in young pigs as they have not yet been colonised by the bacterium. In conclusion, outbreaks of A. pleuropneumoniae on endemic farms are most likely caused by a trigger inducing pneumonia in already infected pigs, but more evidence is needed to identify optimum preventive interventions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Infection dynamics and acute phase response of an Actinobacillus pleuropneumoniae field isolate of moderate virulence in pigs.

PubMed

Gómez-Laguna, Jaime; Islas, Armando; Muñoz, Dennis; Ruiz, Alvaro; Villamil, Aura; Carrasco, Librado; Quezada, Manuel

2014-10-10

Actinobacillus pleuropneumoniae, the causative agent of porcine contagious pleuropneumonia (PCP), causes significant economic losses associated mainly with growth stunting of animals. Although serotypes can be distinguished according to their virulence, most of the studies are focused in A. pleuropneumoniae infections with virulent serotypes. There is little information regarding the role of acute phase proteins (APPs) and proinflammatory cytokines in infections with isolates of mild or moderate virulence. Thus, the present study aims to evaluate the kinetics of infection with an A. pleuropneumoniae serotype 6 (Ap6) field isolate of moderate virulence and the changes in the serum concentration of specific antibodies and different APPs and proinflammatory cytokines. Control animals showed no clinical signs or lesions throughout the study. Infected animals showed increased rectal temperature, respiratory distress and depression from 24hpi, and typical gross and microscopic lesions of PCP from 6hpi onwards. Ap6 was isolated from nasal swabs of four out of five inoculated animals at 24hpi, and from nasal swabs, tonsil and lung samples from all inoculated animals at 72hpi. Specific antibodies against Ap6 or changes in the serum concentration of IL-1β, IL-10 and TNF-α were not detected throughout the study. The serum concentration of IL-6 increased from 6hpi as well as serum A amyloid, C-reactive protein and haptoglobin from 24hpi onwards. Our results highlight the onset of the acute phase response after the infection with a field isolate of A. pleuropneumoniae of moderate virulence from 24hpi onwards which may be of interest in the study of the pathogenesis of this disease. Copyright © 2014 Elsevier B.V. All rights reserved.

Characterization of antigenic determinants in ApxIIA exotoxin capable of inducing protective immunity to Actinobacillus pleuropneumoniae challenge.

PubMed

Seo, Ki-Weon; Kim, Dong-Heon; Kim, Ah Hyun; Yoo, Han-Sang; Lee, Kyung-Yeol; Jang, Yong-Suk

2011-01-01

Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia. Among the virulence factors of the pathogen, ApxIIA, a bacterial exotoxin, is expressed by many serotypes and presents a plausible target for vaccine development. We characterized the region within ApxIIA that induces a protective immune response against bacterial infection using mouse challenge model. Recombinant proteins spanning the length of ApxIIA were produced and antiserum to the full-length ApxIIA was induced in mice. This antiserum recognized fragments #2, #3 and #5 with high binding specificity, but showed poor recognition for fragments #1 and #4. Of the antisera induced in mice by injection of each fragments, only the antiserum to fragment #4 failed to efficiently recognize the full-length antigen, although the individual antisera recognized their cognate antigens with almost equal efficiency. The protective potency of the immunogenic proteins against a challenge injection of bacteria in vivo correlated well with the antibody titer. Fragment #5 induced the highest level of protective activity, comparable to that by the full-length protein. These results support the use of fragment #5 to produce a vaccine against A. pleuropneumoniae challenge, since the small antigen peptide is easier to handle than is the full-length protein and can be expressed efficiently in heterologous expression systems.

Isolation and genetic characterization of an Actinobacillus pleuropneumoniae serovar K12:O3 strain.

PubMed

Ito, Hiroya; Matsumoto, Atsuko

2015-01-01

An atypical Actinobacillus pleuropneumoniae serovar 12 strain, termed QAS106, was isolated from a clinical case of porcine pleuropneumonia in Japan. An immunodiffusion (ID) test identified the strain as serovar 12. However, the ID test also demonstrated that strain QAS106 shared antigenic determinants with both the serovar 3 and 15 reference strains. Strain QAS106 was positive in the capsular serovar 12-specific polymerase chain reaction (PCR) assay, while the PCR toxin gene profiling and omlA PCR typing assays indicated that strain QAS106 was similar to serovar 3. The nucleotide sequence of the 16S ribosomal DNA (rDNA) of strain QAS106 was identical with that of serovars 3 and 12, but it showed 99.7% identity with that of serovar 15. Nucleotide sequence analysis revealed that genes involved in biosynthesis of the capsular polysaccharide (CPS) of strain QAS106 were identical to those of serovar 12 at the amino acid level. On the other hand, strain QAS106 would express putative proteins involved in the biosynthesis of lipopolysaccharide (LPS) O-polysaccharide (O-PS), the amino acid sequences of which were identical or nearly identical to those of serovars 3 and 15. In conclusion, strain QAS106 should be recognized as K12:O3, even though typical serovar 12 strains are K12:O12. The emergence of an atypical A. pleuropneumoniae serovar 12 strain expressing a rare combination of CPS and O-PS antigens would hamper precise serodiagnosis by the use of either CPS- or LPS-based serodiagnostic methodology alone. © 2014 The Author(s).

Experimental Actinobacillus pleuropneumoniae challenge in swine: Comparison of computed tomographic and radiographic findings during disease

PubMed Central

2012-01-01

Background In pigs, diseases of the respiratory tract like pleuropneumonia due to Actinobacillus pleuropneumoniae (App) infection have led to high economic losses for decades. Further research on disease pathogenesis, pathogen-host-interactions and new prophylactic and therapeutic approaches are needed. In most studies, a large number of experimental animals are required to assess lung alterations at different stages of the disease. In order to reduce the required number of animals but nevertheless gather information on the nature and extent of lung alterations in living pigs, a computed tomographic scoring system for quantifying gross pathological findings was developed. In this study, five healthy pigs served as control animals while 24 pigs were infected with App, the causative agent of pleuropneumonia in pigs, in an established model for respiratory tract disease. Results Computed tomographic (CT) findings during the course of App challenge were verified by radiological imaging, clinical, serological, gross pathology and histological examinations. Findings from clinical examinations and both CT and radiological imaging, were recorded on day 7 and day 21 after challenge. Clinical signs after experimental App challenge were indicative of acute to chronic disease. Lung CT findings of infected pigs comprised ground-glass opacities and consolidation. On day 7 and 21 the clinical scores significantly correlated with the scores of both imaging techniques. At day 21, significant correlations were found between clinical scores, CT scores and lung lesion scores. In 19 out of 22 challenged pigs the determined disease grades (not affected, slightly affected, moderately affected, severely affected) from CT and gross pathological examination were in accordance. Disease classification by radiography and gross pathology agreed in 11 out of 24 pigs. Conclusions High-resolution, high-contrast CT examination with no overlapping of organs is superior to radiography in the

Sub-inhibitory concentrations of penicillin G induce biofilm formation by field isolates of Actinobacillus pleuropneumoniae.

PubMed

Hathroubi, S; Fontaine-Gosselin, S-È; Tremblay, Y D N; Labrie, J; Jacques, M

2015-09-30

Actinobacillus pleuropneumoniae is a Gram-negative bacterium and causative agent of porcine pleuropneumonia. This is a highly contagious disease that causes important economic losses to the swine industry worldwide. Penicillins are extensively used in swine production and these antibiotics are associated with high systemic clearance and low oral bioavailability. This may expose A. pleuropneumoniae to sub-inhibitory concentrations of penicillin G when the antibiotic is administered orally. Our goal was to evaluate the effect of sub-minimum inhibitory concentration (MIC) of penicillin G on the biofilm formation of A. pleuropneumoniae. Biofilm production of 13 field isolates from serotypes 1, 5a, 7 and 15 was tested in the presence of sub-MIC of penicillin G using a polystyrene microtiter plate assay. Using microscopy techniques and enzymatic digestion, biofilm architecture and composition were also characterized after exposure to sub-MIC of penicillin G. Sub-MIC of penicillin G significantly induced biofilm formation of nine isolates. The penicillin G-induced biofilms contained more poly-N-acetyl-D-glucosamine (PGA), extracellular DNA and proteins when compared to control biofilms grown without penicillin G. Additionally, penicillin G-induced biofilms were sensitive to DNase which was not observed with the untreated controls. Furthermore, sub-MIC of penicillin G up-regulated the expression of pgaA, which encodes a protein involved in PGA synthesis, and the genes encoding the envelope-stress sensing two-component regulatory system CpxRA. In conclusion, sub-MICs of penicillin G significantly induce biofilm formation and this is likely the result of a cell envelope stress sensed by the CpxRA system resulting in an increased production of PGA and other matrix components. Copyright © 2015 Elsevier B.V. All rights reserved.

Nucleotide sequence analysis of a DNA region involved in capsular polysaccharide biosynthesis reveals the molecular basis of the nontypeability of two Actinobacillus pleuropneumoniae isolates.

PubMed

Ito, Hiroya; Ogawa, Torata; Fukamizu, Dai; Morinaga, Yuiko; Kusumoto, Masahiro

2016-11-01

The aim of our study was to reveal the molecular basis of the serologic nontypeability of 2 Actinobacillus pleuropneumoniae field isolates. Nine field strains of A. pleuropneumoniae, the causative agent of porcine pleuropneumonia, were isolated from pigs raised on the same farm and sent to our diagnostic laboratory for serotyping. Seven of the 9 strains were identified as serovar 15 strains by immunodiffusion tests. However, 2 strains, designated FH24-2 and FH24-5, could not be serotyped with antiserum prepared against serovars 1-15. Strain FH24-5 showed positive results in 2 serovar 15-specific PCR tests, whereas strain FH24-2 was only positive in 1 of the 2 PCR tests. The nucleotide sequence analysis of gene clusters involved in capsular polysaccharide biosynthesis of the 2 nontypeable strains revealed that both had been rendered nontypeable by the action of ISApl1, a transposable element of A. pleuropneumoniae belonging to the IS30 family. The results showed that ISApl1 of A. pleuropneumoniae can interfere with both the serologic and molecular typing methods, and that nucleotide sequence analysis across the capsular gene clusters is the best means of determining the cause of serologic nontypeability in A. pleuropneumoniae. © 2016 The Author(s).

Effects of oral administration of tilmicosin on pulmonary inflammation in piglets experimentally infected with Actinobacillus pleuropneumoniae.

PubMed

Nerland, Erin M; LeBlanc, Justin M; Fedwick, Jason P; Morck, Douglas W; Merrill, John K; Dick, Paul; Paradis, Marie-Anne; Buret, Andre G

2005-01-01

To determine the effects of oral administration of tilmicosin in piglets experimentally infected with Actinobacillus pleuropneumoniae. Forty 3-week-old specific-pathogen free piglets. Piglets were assigned to 1 of 4 groups as follows: 1) uninfected sham-treated control piglets; 2) infected untreated piglets that were intratracheally inoculated with 10(7) CFUs of A pleuropneumoniae; 3) infected treated piglets that were intratracheally inoculated with A pleuropneumoniae and received tilmicosin in feed (400 ppm [microg/g]) for 7 days prior to inoculation; or 4) infected treated piglets that were intratracheally inoculated with A pleuropneumoniae and received chlortetracycline (CTC) in feed (1100 ppm [microg/gl) for 7 days prior to inoculation. Bronchoalveolar lavage (BAL) fluid and lung tissue specimens of piglets for each group were evaluated at 3 or 24 hours after inoculation. For each time point, 4 to 6 piglets/group were studied. Feeding of CTC and tilmicosin decreased bacterial load in lungs of infected piglets. Tilmicosin delivered in feed, but not CTC, enhanced apoptosis in porcine BAL fluid leukocytes. This was associated with a decrease in LTB4 concentrations in BAL fluid of tilmicosin-treated piglets, compared with untreated and CTC-treated piglets, and also with a significant decrease in the number of pulmonary lesions. Tilmicosin inhibited infection-induced increases in rectal temperatures, as measured in untreated and CTC-treated piglets. Pulmonary neutrophil infiltration and prostaglandin E2 concentrations in the BAL fluid were not significantly different among groups at any time. Oral administration of tilmicosin to infected piglets induces apoptosis in BAL fluid leukocytes and decreases BAL fluid LTB4 concentrations and inflammatory lung lesions.

Pharmacokinetic/pharmacodynamic integration and modelling of oxytetracycline for the porcine pneumonia pathogens Actinobacillus pleuropneumoniae and Pasteurella multocida.

PubMed

Dorey, L; Pelligand, L; Cheng, Z; Lees, P

2017-10-01

Pharmacokinetic-pharmacodynamic (PK/PD) integration and modelling were used to predict dosage schedules of oxytetracycline for two pig pneumonia pathogens, Actinobacillus pleuropneumoniae and Pasteurella multocida. Minimum inhibitory concentration (MIC) and mutant prevention concentration (MPC) were determined in broth and porcine serum. PK/PD integration established ratios of average concentration over 48 h (C av0-48 h )/MIC of 5.87 and 0.27 μg/mL (P. multocida) and 0.70 and 0.85 μg/mL (A. pleuropneumoniae) for broth and serum MICs, respectively. PK/PD modelling of in vitro time-kill curves established broth and serum breakpoint values for area under curve (AUC 0-24 h )/MIC for three levels of inhibition of growth, bacteriostasis and 3 and 4 log 10 reductions in bacterial count. Doses were then predicted for each pathogen, based on Monte Carlo simulations, for: (i) bacteriostatic and bactericidal levels of kill; (ii) 50% and 90% target attainment rates (TAR); and (iii) single dosing and daily dosing at steady-state. For 90% TAR, predicted daily doses at steady-state for bactericidal actions were 1123 mg/kg (P. multocida) and 43 mg/kg (A. pleuropneumoniae) based on serum MICs. Lower TARs were predicted from broth MIC data; corresponding dose estimates were 95 mg/kg (P. multocida) and 34 mg/kg (A. pleuropneumoniae). © 2017 The Authors. Journal of Veterinary Pharmacology and Therapeutics Published by John Wiley & Sons Ltd.

What is the true in vitro potency of oxytetracycline for the pig pneumonia pathogens Actinobacillus pleuropneumoniae and Pasteurella multocida?

PubMed

Dorey, L; Hobson, S; Lees, P

2017-10-01

The pharmacodynamics of oxytetracycline was determined for pig respiratory tract pathogens, Actinobacillus pleuropneumoniae and Pasteurella multocida. Indices of potency were determined for the following: (i) two matrices, broth and pig serum; (ii) five overlapping sets of twofold dilutions; and (iii) a high strength starting culture. For A. pleuropneumoniae, minimum inhibitory concentration (MIC) was similar for the two matrices, but for P. multocida, differences were marked and significantly different. MIC and minimum bactericidal concentration (MBC) serum: broth ratios for A. pleuropneumoniae were 0.83:1 and 1.22:1, respectively, and corresponding values for P. multocida were 22.0:1 and 7.34:1. For mutant prevention concentration (MPC) serum: broth ratios were 0.79:1 (A. pleuropneumoniae) and 20.9:1 (P. multocida). These ratios were corrected for serum protein binding to yield fraction unbound (fu) serum: broth MIC ratios of 0.24:1 (A. pleuropneumoniae) and 6.30:1 (P. multocida). Corresponding fu serum: broth ratios for MPC were almost identical, 0.23:1 and 6.08:1. These corrections for protein binding did not account for potency differences between serum and broth for either species; based on fu serum MICs, potency in serum was approximately fourfold greater than predicted for A. pleuropneumoniae and sixfold smaller than predicted for P. multocida. For both broth and serum and both bacterial species, MICs were also dependent on initial inoculum strength. The killing action of oxytetracycline had the characteristics of codependency for both A. pleuropneumoniae and P. multocida in both growth media. The in vitro potency of oxytetracycline in pig serum is likely to be closer to the in vivo plasma/serum concentration required for efficacy than potency estimated in broths. © 2017 The Authors. Journal of Veterinary Pharmacology and Therapeutics Published by John Wiley & Sons Ltd.

Induction of protective immune responses against challenge of Actinobacillus pleuropneumoniae by oral administration with Saccharomyces cerevisiae expressing Apx toxins in pigs.

PubMed

Shin, Min-Kyoung; Kang, Mi Lan; Jung, Myung Hwan; Cha, Seung-Bin; Lee, Won-Jung; Kim, Jung-Mi; Kim, Dae-Hyuk; Yoo, Han Sang

2013-01-15

Actinobacillus pleuropneumoniae is a causative agent of porcine pleuropneumonia, a highly contagious endemic disease of pigs worldwide, inducing significant economic losses worldwide. Apx toxins, which are correlated with the virulence of A. pleuropneumoniae, were expressed in Saccharomyces cerevisiae and its possible use as an oral vaccine has been confirmed in our previous studies using a murine model. The present study was undertaken to test the hypothesis that oral immunization using S. cerevisiae expressing either ApxI or ApxII could protect pigs against A. pleuropneumoniae as an effective way of inducing both mucosal and systemic immune responses. The surface-displayed ApxIIA#5 expressing S. cerevisiae was selected as an oral vaccine candidate by finding on induction of higher immune responses in mice after oral vaccination. The surface-displayed ApxIIA#5 expressing S. cerevisiae and the ApxIA expressing S. cerevisiae were developed to serve as an oral vaccine in pigs. The vaccinated pigs showed higher specific IgG- and IgA-related antibody activities than the non-treated control and vector control pigs. Additionally, the induced immune responses were found to protect pigs infected with A. pleuropneumoniae according to the analysis of clinical signs and the gross and microscopic pulmonary lesions. These results suggested that the surface-displayed ApxIIA#5 and ApxIA in S. cerevisiae might be a potential oral vaccine to protect pigs against porcine pleuropneumonia. Thus the present study is expected to contribute to the development of a live oral vaccine against porcine pleuropneumonia as an alternative to current conventional vaccines. Copyright © 2012 Elsevier B.V. All rights reserved.

Simultaneous Detection of Antibodies against Apx Toxins ApxI, ApxII, ApxIII, and ApxIV in Pigs with Known and Unknown Actinobacillus pleuropneumoniae Exposure Using a Multiplexing Liquid Array Platform

PubMed Central

Giménez-Lirola, Luis G.; Jiang, Yong-Hou; Sun, Dong; Hoang, Hai; Yoon, Kyoung-Jin; Halbur, Patrick G.

2014-01-01

Surveillance for the presence of Actinobacillus pleuropneumoniae infection in a population plays a central role in controlling the disease. In this study, a 4-plex fluorescent microbead-based immunoassay (FMIA), developed for the simultaneous detection of IgG antibodies to repeat-in-toxin (RTX) toxins (ApxI, ApxII, ApxIII, and ApxIV) of A. pleuropneumoniae, was evaluated using (i) blood serum samples from pigs experimentally infected with each of the 15 known A. pleuropneumoniae serovars or with Actinobacillus suis, (ii) blood serum samples from pigs vaccinated with a bacterin containing A. pleuropneumoniae serovar 1, 3, 5, or 7, and (iii) blood serum samples from pigs with an unknown A. pleuropneumoniae exposure status. The results were compared to those obtained in a previous study where a dual-plate complement fixation test (CFT) and three commercially available enzyme-linked immunosorbent assays (ELISAs) were conducted on the same sample set. On samples from experimentally infected pigs, the 4-plex Apx FMIA detected specific seroconversion to Apx toxins as early as 7 days postinfection in a total of 29 pigs inoculated with 14 of the 15 A. pleuropneumoniae serovars. Seroconversion to ApxII and ApxIII was detected by FMIA in pigs inoculated with A. suis. The vaccinated pigs showed poor humoral responses against ApxI, ApxII, ApxIII, and ApxIV. In the field samples, the humoral response to ApxIV and the A. pleuropneumoniae seroprevalence increased with age. This novel FMIA (with a sensitivity of 82.7% and a specificity of 100% for the anti-ApxIV antibody) was found to be more sensitive and accurate than current tests (sensitivities, 9.5 to 56%; specificity, 100%) and is potentially an improved tool for the surveillance of disease and for monitoring vaccination compliance. PMID:24226091

Transmission of Actinobacillus pleuropneumoniae among weaned piglets on endemically infected farms.

PubMed

Tobias, T J; Bouma, A; van den Broek, J; van Nes, A; Daemen, A J J M; Wagenaar, J A; Stegeman, J A; Klinkenberg, D

2014-11-01

Clinical outbreaks due to Actinobacillus pleuropneumoniae occur recurrently, despite the wide-scale use of antimicrobials or vaccination. Therefore, new approaches for the prevention and control of these outbreaks are necessary. For the development of alternative measures, more insight into the transmission of the bacterium on farms is necessary. The aim of this cohort study was to quantify transmission of A. pleuropneumoniae amongst weaned piglets on farms. We investigated three possible transmission routes: (i) indirect transmission by infected piglets within the same compartment, (ii) transmission by infected pigs in adjacent pens and (iii) transmission by direct contact within pens. Additionally, we evaluated the effect of independent litter characteristics on the probability of infection. Two farms participated in our study. Serum and tonsil brush samples were collected from sows pre-farrowing. Serum was analysed for antibodies against Apx toxins and Omp. Subsequently, tonsil brush samples were collected from all piglets from these dams (N=542) in three cohorts, 3 days before weaning and 6 weeks later. Tonsil samples were analysed by qPCR for the presence of the apxIVA gene of A. pleuropneumoniae. Before weaning, 25% of the piglets tested positive; 6 weeks later 47% tested positive. Regression and stochastic transmission models were used to assess the contribution of each of the three transmission routes and to estimate transmission rates. Transmission between piglets in adjacent pens did not differ significantly from that between non-adjacent pens. The transmission rate across pens was estimated to be 0.0058 day(-1) (95% CI: 0.0030-0.010), whereas the transmission rate within pens was ten times higher 0.059 day(-1) (95% CI: 0.048-0.072). Subsequently, the effects of parity and serological response of the dam and litter age at weaning on the probability of infection of pigs were evaluated by including these into the regression model. A higher dam Apx

The Lon protease homologue LonA, not LonC, contributes to the stress tolerance and biofilm formation of Actinobacillus pleuropneumoniae.

PubMed

Xie, Fang; Li, Gang; Zhang, Yanhe; Zhou, Long; Liu, Shuanghong; Liu, Siguo; Wang, Chunlai

2016-04-01

Lon proteases are a family of ATP-dependent proteases that are involved in the degradation of abnormal proteins in bacteria exposed to adverse environmental stress. An analysis of the genome sequence of Actinobacillus pleuropneumoniae revealed the unusual presence of two putative ATP-dependent Lon homologues, LonA and LonC. Sequence comparisons indicated that LonA has the classical domain organization of the LonA subfamily, which includes the N-terminal domain, central ATPase (AAA) domain, and C-terminal proteolytic (P) domain. LonC belongs to the recently classified LonC subfamily, which includes Lon proteases that contain neither the N-terminal domain of LonA nor the transmembrane region that is present only in LonB subfamily members. To investigate the roles of LonA and LonC in A. pleuropneumoniae, mutants with deletions in the lonA and lonC genes were constructed. The impaired growth of the △lonA mutant exposed to low and high temperatures and osmotic and oxidative stress conditions indicates that the LonA protease is required for the stress tolerance of A. pleuropneumoniae. Furthermore, the △lonA mutant exhibited significantly reduced biofilm formation compared to the wild-type strain. However, no significant differences in stress responses or biofilm formation were observed between the △lonC mutant and the wild-type strain. The △lonA mutant exhibited reduced colonization ability and attenuated virulence of A. pleuropneumoniae in the BALB/c mouse model compared to the wild-type strain. Disruption of lonC gene did not significantly influence the colonization and virulence of A. pleuropneumoniae. The data presented in this study illustrate that the LonA protease, but not the LonC protease, is required for the stress tolerance, biofilm formation and pathogenicity of A. pleuropneumoniae. Copyright © 2016 Elsevier Ltd. All rights reserved.

Host Cell Contact-Induced Transcription of the Type IV Fimbria Gene Cluster of Actinobacillus pleuropneumoniae

PubMed Central

Boekema, Bouke K. H. L.; Van Putten, Jos P. M.; Stockhofe-Zurwieden, Norbert; Smith, Hilde E.

2004-01-01

Type IV pili (Tfp) of gram-negative species share many characteristics, including a common architecture and conserved biogenesis pathway. Much less is known about the regulation of Tfp expression in response to changing environmental conditions. We investigated the diversity of Tfp regulatory systems by searching for the molecular basis of the reported variable expression of the Tfp gene cluster of the pathogen Actinobacillus pleuropneumoniae. Despite the presence of an intact Tfp gene cluster consisting of four genes, apfABCD, no Tfp were formed under standard growth conditions. Sequence analysis of the predicted major subunit protein ApfA showed an atypical alanine residue at position −1 from the prepilin peptidase cleavage site in 42 strains. This alanine deviates from the consensus glycine at this position in Tfp from other species. Yet, cloning of the apfABCD genes under a constitutive promoter in A. pleuropneumoniae resulted in pilin and Tfp assembly. Tfp promoter-luxAB reporter gene fusions demonstrated that the Tfp promoter was intact but tightly regulated. Promoter activity varied with bacterial growth phase and was detected only when bacteria were grown in chemically defined medium. Infection experiments with cultured epithelial cells demonstrated that Tfp promoter activity was upregulated upon adherence of the pathogen to primary cultures of lung epithelial cells. Nonadherent bacteria in the culture supernatant exhibited virtually no promoter activity. A similar upregulation of Tfp promoter activity was observed in vivo during experimental infection of pigs. The host cell contact-induced and in vivo-upregulated Tfp promoter activity in A. pleuropneumoniae adds a new dimension to the diversity of Tfp regulation. PMID:14742510

Immunological study of an attenuated Salmonella Typhimurium expressing ApxIA, ApxIIA, ApxIIIA and OmpA of Actinobacillus pleuropneumoniae in a mouse model.

PubMed

Hur, Jin; Eo, Seong Kug; Park, Sang-Youel; Choi, Yoonyoung; Lee, John Hwa

2016-01-01

Salmonella Typhimurium strain expressing the Actinobacillus pleuropneumoniae antigens, ApxIA, ApxIIA, ApxIIIA and OmpA, was previously constructed as a vaccine candidate for porcine pleuropneumonia. This strain was a live attenuated (∆lon∆cpxR∆asd)Salmonella as a delivery host and contained a vector containing asd. An immunological study of lymphocyte proliferation, T-lymphocyte subsets and cytokines in the splenocytes of a mouse model was carried out after stimulation with the candidate Salmonella Typhimurium by intranasal inoculation. The splenic lymphocyte proliferation and the levels of IL-4, IL-6 and IL-12 of the inoculated mice were significantly increased, and the T- and B-cell populations were also elevated. Collectively, the candidate may efficiently induce the Th1- and Th2-type immune responses.

Concurrent host-pathogen gene expression in the lungs of pigs challenged with Actinobacillus pleuropneumoniae.

PubMed

Brogaard, Louise; Klitgaard, Kirstine; Heegaard, Peter M H; Hansen, Mette Sif; Jensen, Tim Kåre; Skovgaard, Kerstin

2015-05-28

Actinobacillus pleuropneumoniae causes pleuropneumonia in pigs, a disease which is associated with high morbidity and mortality, as well as impaired animal welfare. To obtain in-depth understanding of this infection, the interplay between virulence factors of the pathogen and defense mechanisms of the porcine host needs to be elucidated. However, research has traditionally focused on either bacteriology or immunology; an unbiased picture of the transcriptional responses can be obtained by investigating both organisms in the same biological sample. Host and pathogen responses in pigs experimentally infected with A. pleuropneumoniae were analyzed by high-throughput RT-qPCR. This approach allowed concurrent analysis of selected genes encoding proteins known or hypothesized to be important in the acute phase of this infection. The expression of 17 bacterial and 31 porcine genes was quantified in lung samples obtained within the first 48 hours of infection. This provided novel insight into the early time course of bacterial genes involved in synthesis of pathogen-associated molecular patterns (lipopolysaccharide, peptidoglycan, lipoprotein) and genes involved in pattern recognition (TLR4, CD14, MD2, LBP, MYD88) in response to A. pleuropneumoniae. Significant up-regulation of proinflammatory cytokines such as IL1B, IL6, and IL8 was observed, correlating with protein levels, infection status and histopathological findings. Host genes encoding proteins involved in iron metabolism, as well as bacterial genes encoding exotoxins, proteins involved in adhesion, and iron acquisition were found to be differentially expressed according to disease progression. By applying laser capture microdissection, porcine expression of selected genes could be confirmed in the immediate surroundings of the invading pathogen. Microbial pathogenesis is the product of interactions between host and pathogen. Our results demonstrate the applicability of high-throughput RT-qPCR for the elucidation

Molecular serotyping and antimicrobial resistance profiles of Actinobacillus pleuropneumoniae isolated from pigs in South Korea.

PubMed

Kim, Boram; Hur, Jin; Lee, Ji Yeong; Choi, Yoonyoung; Lee, John Hwa

2016-09-01

Actinobacillus pleuropneumoniae (APP) causes porcine pleuropneumonia (PP). Serotypes and antimicrobial resistance patterns in APP isolates from pigs in Korea were examined. Sixty-five APP isolates were genetically serotyped using standard and multiplex PCR (polymerase chain reaction). Antimicrobial susceptibilities were tested using the standardized disk-agar method. PCR was used to detect β-lactam, gentamicin and tetracycline-resistance genes. The random amplified polymorphic DNA (RAPD) patterns were determined by PCR. Korean pigs predominantly carried APP serotypes 1 and 5. Among 65 isolates, one isolate was sensitive to all 12 antimicrobials tested in this study. Sixty-two isolates was resistant to tetracycline and 53 isolates carried one or five genes including tet(B), tet(A), tet(H), tet(M)/tet(O), tet(C), tet(G) and/or tet(L)-1 markers. Among 64 strains, 9% and 26.6% were resistance to 10 and three or more antimicrobials, respectively. Thirteen different antimicrobial resistance patterns were observed and RAPD analysis revealed a separation of the isolates into two clusters: cluster II (6 strains resistant to 10 antimicrobials) and cluster I (the other 59 strains). Results show that APP serotypes 1 and 5 are the most common in Korea, and multi-drug resistant strains are prevalent. RAPD analysis demonstrated that six isolates resistant to 10 antimicrobials belonged to the same cluster.

Factors influencing the potency of marbofloxacin for pig pneumonia pathogens Actinobacillus pleuropneumoniae and Pasteurella multocida.

PubMed

Dorey, L; Hobson, S; Lees, P

2017-04-01

For the pig respiratory tract pathogens, Actinobacillus pleuropneumoniae and Pasteurella multocida, Minimum Inhibitory Concentration (MIC) of marbofloxacin was determined in recommended broths and pig serum at three inoculum strengths. MICs in both growth matrices increased progressively from low, through medium to high starting inoculum counts, 10 4 , 10 6 and 10 8 CFU/mL, respectively. P. multocida MIC ratios for high:low inocula were 14:4:1 for broth and 28.2:1 for serum. Corresponding MIC ratios for A. pleuropneumoniae were lower, 4.1:1 (broth) and 9.2:1 (serum). MIC high:low ratios were therefore both growth matrix and bacterial species dependent. The effect of alterations to the chemical composition of broths and serum on MIC were also investigated. Neither adjusting broth or serum pH in six increments over the range 7.0 to 8.0 nor increasing calcium and magnesium concentrations of broth in seven incremental steps significantly affected MICs for either organism. In time-kill studies, the killing action of marbofloxacin had the characteristics of concentration dependency against both organisms in both growth matrices. It is concluded that MIC and time-kill data for marbofloxacin, generated in serum, might be preferable to broth data, for predicting dosages of marbofloxacin for clinical use. Copyright © 2016 Elsevier Ltd. All rights reserved.

Treatment of pigs experimentally infected with Mycoplasma hyopneumoniae, Pasteurella multocida, and Actinobacillus pleuropneumoniae with various antibiotics.

PubMed Central

Stipkovits, L; Miller, D; Glavits, R; Fodor, L; Burch, D

2001-01-01

The authors have performed a comparative study of the efficacy of various in-feed medications for the treatment of 5- to 6-week-old specific pathogen-free (SPF) piglets experimentally infected on day 1 with Mycoplasma hyopneumoniae, on day 8 with Pasteurella multocida (serotype A), and on day 15 with Actinobacillus pleuropneumoniae (serotype 2). The treatment started on day 9 and continued for 12 consecutive days, then the piglets were euthanized for examination of macroscopic, histologic, and pathologic lesions and for the presence of mycoplasmas and bacteria in the lungs. Based on the results of clinical observations (respiratory signs, rectal temperature, body weight gain, and feed conversion efficiency), macroscopic and histologic lesions of the lungs, and microbiologic findings, the best results were obtained by treatment of pigs with Econor + chlortetracycline, followed by Tetramutin, Pulmotil, Cyfac, and lincomycin + chlortetracycline. PMID:11768127

Trimeric autotransporter adhesins contribute to Actinobacillus pleuropneumoniae pathogenicity in mice and regulate bacterial gene expression during interactions between bacteria and porcine primary alveolar macrophages.

PubMed

Qin, Wanhai; Wang, Lei; Zhai, Ruidong; Ma, Qiuyue; Liu, Jianfang; Bao, Chuntong; Zhang, Hu; Sun, Changjiang; Feng, Xin; Gu, Jingmin; Du, Chongtao; Han, Wenyu; Langford, P R; Lei, Liancheng

2016-01-01

Actinobacillus pleuropneumoniae is an important pathogen that causes respiratory disease in pigs. Trimeric autotransporter adhesin (TAA) is a recently discovered bacterial virulence factor that mediates bacterial adhesion and colonization. Two TAA coding genes have been found in the genome of A. pleuropneumoniae strain 5b L20, but whether they contribute to bacterial pathogenicity is unclear. In this study, we used homologous recombination to construct a double-gene deletion mutant, ΔTAA, in which both TAA coding genes were deleted and used it in in vivo and in vitro studies to confirm that TAAs participate in bacterial auto-aggregation, biofilm formation, cell adhesion and virulence in mice. A microarray analysis was used to determine whether TAAs can regulate other A. pleuropneumoniae genes during interactions with porcine primary alveolar macrophages. The results showed that deletion of both TAA coding genes up-regulated 36 genes, including ene1514, hofB and tbpB2, and simultaneously down-regulated 36 genes, including lgt, murF and ftsY. These data illustrate that TAAs help to maintain full bacterial virulence both directly, through their bioactivity, and indirectly by regulating the bacterial type II and IV secretion systems and regulating the synthesis or secretion of virulence factors. This study not only enhances our understanding of the role of TAAs but also has significance for those studying A. pleuropneumoniae pathogenesis.

Pharmacokinetic and Pharmacodynamic Evaluation of Marbofloxacin in Pig against Korean Local Isolates of Actinobacillus pleuropneumoniae.

PubMed

Hossain, Md Akil; Park, Hae-Chul; Jeong, Kyunghun; Jang, Yang Ho; Kim, Dae Gyun; Kang, JeongWoo; Lee, Kwang-Jick

2017-01-01

The pharmacokinetics of marbofloxacin in pigs after intravenous (i.v.), intramuscular (i.m.), and peroral (p.o.) administration and pharmacokinetic/pharmacodynamic indices of this drug against Korean local isolates of Actinobacillus pleuropneumoniae were determined in this study. Marbofloxacin (2.50 mg/kg of body weight) was administered, and blood samples were collected with designated time intervals. Plasma-extracted marbofloxacin was injected into the LC-MS/MS system. The in vitro and ex vivo antibacterial activities of marbofloxacin were evaluated against 20 isolates of A. pleuropneumoniae . The mean peak plasma concentrations ( C max ) after i.v., i.m., and p.o administration were 2.60 ± 0.10, 2.59 ± 0.12, and 2.34 ± 0.12  µ g/mL at 0.25 ± 0.00, 0.44 ± 0.10, and 1.58 ± 0.40 h, respectively. The area under the plasma concentration-time curves (AUC 0-24 ) and elimination half-lives were 24.80 ± 0.90, 25.80 ± 1.40, and 23.40 ± 5.00 h· μ g/mL and 8.60 ± 0.30, 12.80 ± 1.10, and 8.60 ± 0.00 h, for i.v., i.m., and p.o. administration, correspondingly. The AUC 0-24 /MICs of marbofloxacin after i.v., i.m., and p.o. administration were 253.86 ± 179.91, 264.1 ± 187.16, and 239.53 ± 169.75 h, respectively. The C max /MIC values were 26.58 ± 18.84, 26.48 ± 18.77, and 23.94 ± 16.97, and T>MICs were 42.80 ± 1.01, 36.40 ± 1.24, and 38.60 ± 1.18 h, after i.v., i.m., and p.o. administration, respectively. Thus, marbofloxacin dosage of 2.50 mg/kg of body weight by i.v., i.m., and p.o. administration with 24 h dosing interval will provide effective treatment for the infection of pig by A. pleuropneumonia .

Impact of Actinobacillus pleuropneumoniae biofilm mode of growth on the lipid A structures and stimulation of immune cells.

PubMed

Hathroubi, Skander; Beaudry, Francis; Provost, Chantale; Martelet, Léa; Segura, Mariela; Gagnon, Carl A; Jacques, Mario

2016-07-01

Actinobacillus pleuropneumoniae (APP), the etiologic agent of porcine pleuropneumonia, forms biofilms on biotic and abiotic surfaces. APP biofilms confers resistance to antibiotics. To our knowledge, no studies have examined the role of APP biofilm in immune evasion and infection persistence. This study was undertaken to (i) investigate biofilm-associated LPS modifications occurring during the switch to biofilm mode of growth; and (ii) characterize pro-inflammatory cytokines expression in porcine pulmonary alveolar macrophages (PAMs) and proliferation in porcine PBMCs challenged with planktonic or biofilm APP cells. Extracted lipid A samples from biofilm and planktonic cultures were analyzed by HPLC high-resolution, accurate mass spectrometry. Biofilm cells displayed significant changes in lipid A profiles when compared with their planktonic counterparts. Furthermore, in vitro experiments were conducted to examine the inflammatory response of PAMs exposed to UV-inactivated APP grown in biofilm or in suspension. Relative mRNA expression of pro-inflammatory genes IL1, IL6, IL8 and MCP1 decreased in PAMs when exposed to biofilm cells compared to planktonic cells. Additionally, the biofilm state reduced PBMCs proliferation. Taken together, APP biofilm cells show a weaker ability to stimulate innate immune cells, which could be due, in part, to lipid A structure modifications. © The Author(s) 2016.

Mechanisms underlying Actinobacillus pleuropneumoniae exotoxin ApxI induced expression of IL-1β, IL-8 and TNF-α in porcine alveolar macrophages

PubMed Central

2011-01-01

Actinobacillus pleuropneumoniae (A. pleuropneumoniae) causes fibrino-hemorrhagic necrotizing pleuropneumonia in pigs. Production of proinflammatory mediators in the lungs is an important feature of A. pleuropneumoniae infection. However, bacterial components other than lipopolysaccharide involved in this process remain unidentified. The goals of this study were to determine the role of A. pleuropneumoniae exotoxin ApxI in cytokine induction and to delineate the underlying mechanisms. Using real-time quantitative PCR analysis, we found native ApxI stimulated porcine alveolar macrophages (PAMs) to transcribe mRNAs of IL-1β, IL-8 and TNF-α in a concentration- and time-dependent manner. Heat-inactivation or pre-incubation of ApxI with a neutralizing antiserum attenuated ApxI bioactivity to induce cytokine gene expression. The secretion of IL-1β, IL-8 and TNF-α protein from PAMs stimulated with ApxI was also confirmed by quantitative ELISA. In delineating the underlying signaling pathways contributing to cytokine expression, we observed mitogen-activated protein kinases (MAPKs) p38 and cJun NH2-terminal kinase (JNK) were activated upon ApxI stimulation. Administration of an inhibitor specific to p38 or JNK resulted in varying degrees of attenuation on ApxI-induced cytokine expression, suggesting the differential regulatory roles of p38 and JNK in IL-1β, IL-8 and TNF-α production. Further, pre-incubation of PAMs with a CD18-blocking antibody prior to ApxI stimulation significantly reduced the activation of p38 and JNK, and subsequent expression of IL-1β, IL-8 or TNF-α gene, indicating a pivotal role of β2 integrins in the ApxI-mediated effect. Collectively, this study demonstrated ApxI induces gene expression of IL-1β, IL-8 and TNF-α in PAMs that involves β2 integrins and downstream MAPKs. PMID:21314908

Effect of bovine apo-lactoferrin on the growth and virulence of Actinobacillus pleuropneumoniae.

PubMed

Luna-Castro, Sarahí; Aguilar-Romero, Francisco; Samaniego-Barrón, Luisa; Godínez-Vargas, Delfino; de la Garza, Mireya

2014-10-01

Actinobacillus pleuropneumoniae (App) is a Gram-negative bacterium that causes porcine pleuropneumonia, leading to economic losses in the swine industry. Due to bacterial resistance to antibiotics, new treatments for this disease are currently being sought. Lactoferrin (Lf) is an innate immune system glycoprotein of mammals that is microbiostatic and microbicidal and affects several bacterial virulence factors. The aim of this study was to investigate whether bovine iron-free Lf (BapoLf) has an effect on the growth and virulence of App. Two serotype 1 strains (reference strain S4074 and the isolate BC52) and a serotype 7 reference strain (WF83) were analyzed. First, the ability of App to grow in iron-charged BLf was discarded because in vivo, BapoLf sequesters iron and could be a potential source of this element favoring the infection. The minimum inhibitory concentration of BapoLf was 14.62, 11.78 and 10.56 µM for the strain BC52, S4074 and WF83, respectively. A subinhibitory concentration (0.8 µM) was tested by assessing App adhesion to porcine buccal epithelial cells, biofilm production, and the secretion and function of toxins and proteases. Decrease in adhesion (24-42 %) was found in the serotype 1 strains. Biofilm production decreased (27 %) for only the strain 4074 of serotype 1. Interestingly, biofilm was decreased (60-70 %) in the three strains by BholoLf. Hemolysis of erythrocytes and toxicity towards HeLa cells were not affected by BapoLf. In contrast, proteolytic activity in all strains was suppressed in the presence of BapoLf. Finally, oxytetracycline produced synergistic effect with BapoLf against App. Our results suggest that BapoLf affects the growth and several of the virulence factors in App.

Nasal immunization with M cell-targeting ligand-conjugated ApxIIA toxin fragment induces protective immunity against Actinobacillus pleuropneumoniae infection in a murine model.

PubMed

Park, Jisang; Seo, Ki-Weon; Kim, Sae-Hae; Lee, Ha-Yan; Kim, Bumseok; Lim, Chae Woong; Kim, Jin-Hee; Yoo, Han Sang; Jang, Yong-Suk

2015-05-15

Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia and severe economic loss in the swine industry has been caused by the infection. Therefore, the development of an effective vaccine against the bacteria is necessary. ApxII toxin, among several virulence factors expressed by the bacteria, is considered to be a promising vaccine candidate because ApxII toxin not only accompanies cytotoxic and hemolytic activities, but is also expressed in all 15 serotypes of bacteria except serotypes 10 and 14. In this study, we identified the peptide ligand capable of targeting the ligand-conjugated ApxIIA #5 fragment antigen to nasopharynx-associated lymphoid tissue. It was found that nasal immunization with ligand-conjugated ApxIIA #5 induced efficient mucosal and systemic immune responses measured at the levels of antigen-specific antibodies, cytokine-secreting cells after antigen exposure, and antigen-specific lymphocyte proliferation. More importantly, the nasal immunization induced protective immunity against nasal challenge infection of the bacteria, which was confirmed by histopathological studies and bacterial clearance after challenge infection. Collectively, we confirmed that the ligand capable of targeting the ligand-conjugated antigen to nasopharynx-associated lymphoid tissue can be used as an effective nasal vaccine adjuvant to induce protective immunity against A. pleuropneumoniae infection. Copyright © 2015 Elsevier B.V. All rights reserved.

Deletion of the znuA virulence factor attenuates Actinobacillus pleuropneumoniae and confers protection against homologous or heterologous strain challenge.

PubMed

Yuan, Fangyan; Liao, Yonghong; You, Wujin; Liu, Zewen; Tan, Yongqiang; Zheng, Chengkun; BinWang; Zhou, Danna; Tian, Yongxiang; Bei, Weicheng

2014-12-05

The znuA gene is known to be important for growth and survival in Escherichia coli, Haemophilus spp., Neisseria gonorrhoeae, and Pasteurella multocida under low Zn(2+) conditions. This gene is also present in Actinobacillus pleuropneumoniae serotype 1; therefore, the aim of this study was to investigate the existence of a similar role for the znuA gene in the growth and virulence of this organism. A precisely defined ΔznuA deletion mutant of A. pleuropneumoniae was constructed based on the sequence of the wild-type SLW01 using transconjugation and counterselection. This mutation was found to be lethal in low-Zn(2+) medium. Furthermore, the ΔznuA mutant strain exhibited attenuated virulence (≥22-fold) as well as reduced mortality and morbidity in a murine (Balb/C) model of infection. The majority of the bacteria were cleared from the lungs within 2 weeks. The ΔznuA mutant strain caused no adverse effects in pigs at doses of up to 1.0×10(9) CFU/mL. The ΔznuA mutant strain induced a significant immune response and conferred 80% and 100% protection on immunised pigs against challenge with A. pleuropneumoniae strains belonging to homologous or heterologous serovars, respectively, compared to the blank controls. The data obtained in this study indicate the potential of the mutant ΔznuA strain for development as a live vaccine capable of inducing reliable cross-serovar protection following intratracheal immunisation. Copyright © 2014 Elsevier B.V. All rights reserved.

Genetic and antigenic characteristics of ApxIIA and ApxIIIA from Actinobacillus pleuropneumoniae serovars 2, 3, 4, 6, 8 and 15.

PubMed

To, Ho; Nagai, Shinya; Iwata, Akira; Koyama, Tomohiro; Oshima, Atsushi; Tsutsumi, Nobuyuki

2016-07-01

Apx toxins produced by Actinobacillus pleuropneumoniae are essential components of new generation vaccines. In this study, apxIIA and apxIIIA genes of serovars 2, 3, 4, 6, 8 and 15 were cloned and sequenced. Amino acid sequences of ApxIIA proteins of serovars 2, 3, 4, 6, 8 and 15 were almost identical to those of serovars 1, 5, 7, 9 and 11-13. Immunoblot analysis showed that rApxIIA from serovars 2 and 15 reacts strongly with sera from animals infected with various serovars. Sequence analysis revealed that ApxIIIA proteins has two variants, one in strains of serovar 2 and the other in strains of serovars 3, 4, 6, 8 and 15. A mouse cross-protection study showed that mice actively immunized with rApxIIIA/2 or rApxIIIA/15 are protected against challenge with A. pleuropneumoniae strains of serovars 3, 4, 6, 8, 15, and 2 expressing ApxIII/15 and ApxIII/2, respectively. Similarly, mice passively immunized with rabbit anti-rApxIIIA/2 or anti-rApxIIIA/15 sera were found to be protected against challenge with strains of serovars 2 and 15. Our study revealed antigenic and sequence similarities within ApxIIA and ApxIIIA proteins, which may help in the development of effective vaccines against disease caused by A. pleuropneumoniae. © 2016 The Societies and John Wiley & Sons Australia, Ltd.

The live attenuated Actinobacillus pleuropneumoniae triple-deletion mutant ΔapxIC ΔapxIIC ΔapxIV-ORF1 strain, SLW05, Immunizes pigs against lethal challenge with Haemophilus parasuis.

PubMed

Fu, Shulin; Ou, Jiwen; Zhang, Minmin; Xu, Juan; Liu, Huazhen; Liu, Jinlin; Yuan, Fangyan; Chen, Huanchun; Bei, Weicheng

2013-02-01

Haemophilus parasuis and Actinobacillus pleuropneumoniae both belong to the family Pasteurellaceae and are major respiratory pathogens that cause large economic losses in the pig industry worldwide. We previously constructed an attenuated A. pleuropneumoniae serovar 1 live vaccine prototype, SLW05 (ΔapxIC ΔapxIIC ΔapxIV-ORF1), which is able to produce nontoxic but immunogenic ApxIA, ApxIIA, and ApxIVA. This triple-deletion mutant strain was shown to elicit protective immunity against virulent A. pleuropneumoniae. In the present study, we investigated whether immunization with SLW05 could also protect against lethal challenge with virulent H. parasuis SH0165 (serovar 5) or MD0322 (serovar 4). The SLW05 strain was found to elicit a strong humoral antibody response in pigs and to confer significant protection against challenge with a lethal dose of H. parasuis SH0165 or MD0322. IgG subtype analysis revealed that SLW05 induces a bias toward a Th1-type immune response and stimulates interleukin 2 (IL-2) and gamma interferon (IFN-γ) production. Moreover, antisera from SLW05-vaccinated pigs efficiently inhibited both A. pleuropneumoniae and H. parasuis growth in a whole-blood assay. This is the first report that a live attenuated A. pleuropneumoniae vaccine with SLW05 can protect against lethal H. parasuis infection, which provides a novel approach for developing an attenuated H. parasuis vaccine.

The Live Attenuated Actinobacillus pleuropneumoniae Triple-Deletion Mutant ΔapxIC ΔapxIIC ΔapxIV-ORF1 Strain, SLW05, Immunizes Pigs against Lethal Challenge with Haemophilus parasuis

PubMed Central

Fu, Shulin; Ou, Jiwen; Zhang, Minmin; Xu, Juan; Liu, Huazhen; Liu, Jinlin; Yuan, Fangyan; Chen, Huanchun

2013-01-01

Haemophilus parasuis and Actinobacillus pleuropneumoniae both belong to the family Pasteurellaceae and are major respiratory pathogens that cause large economic losses in the pig industry worldwide. We previously constructed an attenuated A. pleuropneumoniae serovar 1 live vaccine prototype, SLW05 (ΔapxIC ΔapxIIC ΔapxIV-ORF1), which is able to produce nontoxic but immunogenic ApxIA, ApxIIA, and ApxIVA. This triple-deletion mutant strain was shown to elicit protective immunity against virulent A. pleuropneumoniae. In the present study, we investigated whether immunization with SLW05 could also protect against lethal challenge with virulent H. parasuis SH0165 (serovar 5) or MD0322 (serovar 4). The SLW05 strain was found to elicit a strong humoral antibody response in pigs and to confer significant protection against challenge with a lethal dose of H. parasuis SH0165 or MD0322. IgG subtype analysis revealed that SLW05 induces a bias toward a Th1-type immune response and stimulates interleukin 2 (IL-2) and gamma interferon (IFN-γ) production. Moreover, antisera from SLW05-vaccinated pigs efficiently inhibited both A. pleuropneumoniae and H. parasuis growth in a whole-blood assay. This is the first report that a live attenuated A. pleuropneumoniae vaccine with SLW05 can protect against lethal H. parasuis infection, which provides a novel approach for developing an attenuated H. parasuis vaccine. PMID:23220998

Apa2H1, the first head domain of Apa2 trimeric autotransporter adhesin, activates mouse bone marrow-derived dendritic cells and immunization with Apa2H1 protects against Actinobacillus pleuropneumoniae infection.

PubMed

Qin, Wanhai; Wang, Lei; Zhai, Ruidong; Ma, Qiuyue; Liu, Jianfang; Bao, Chuntong; Sun, Diangang; Zhang, Hu; Sun, Changjiang; Feng, Xin; Gu, Jingmin; Du, Chongtao; Han, Wenyu; Langford, P R; Lei, Liancheng

2017-01-01

Actinobacillus pleuropneumoniae is the causative pathogen of porcine pleuropneumonia, which results in large economic losses in the pig industry worldwide. There are, however, no effective subunit vaccines are available in the market owing to the various serotypes and the absence of cross-protection against this pathogen. Therefore, the selection of protective components is of great significance for vaccine development. We previously showed that trimeric autotransporter adhesins are important virulence factors of A. pleuropneumoniae. To determine the potential role in vaccine development of the functional head domain (Apa2H1) of Apa2, a trimeric autotransporter adhesin found in A. pleuropneumoniae, we obtained nature-like trimeric Apa2H1 using a prokaryotic expression system and co-culture of Apa2H1 with bone marrow derived dendritic cells (BMDCs) in vitro resulted in maturation of BMDCs, characterised by the up-regulation of CD83, MHC-II, CCR7, ICAM-I and the increased expression of factors related to B lymphoid cells stimulation, such as proliferation-inducing ligand (APRIL), B lymphocyte stimulator (BLyS) and B cell activating factor (BAFF). The in vivo results showed that vaccination with Apa2H1 resulted in the robust production of antigen-specific antibodies, modestly induced mixed Th1 and Th2 immunity, impaired bacterial colonization and dissemination, and improved mouse survival rates. This study is the first to show that Apa2H1 is antigenic and can be used as a component of a subunit vaccine against A. pleuropneumoniae infection, providing valuable reference material for the development of an effective vaccine against A. pleuropneumoniae. Copyright © 2016 Elsevier Ltd. All rights reserved.

Frequency of Th17 cells correlates with the presence of lung lesions in pigs chronically infected with Actinobacillus pleuropneumoniae.

PubMed

Sassu, Elena L; Ladinig, Andrea; Talker, Stephanie C; Stadler, Maria; Knecht, Christian; Stein, Heiko; Frömbling, Janna; Richter, Barbara; Spergser, Joachim; Ehling-Schulz, Monika; Graage, Robert; Hennig-Pauka, Isabel; Gerner, Wilhelm

2017-02-06

Porcine contagious pleuropneumonia caused by Actinobacillus pleuropneumoniae (APP) remains one of the major causes of poor growth performance and respiratory disease in pig herds. While the role of antibodies against APP has been intensely studied, the porcine T cell response remains poorly characterized. To address this, pigs were intranasally infected with APP serotype 2 and euthanized during the acute phase [6-10 days post-infection (dpi)] or the chronic phase of APP infection (27-31 dpi). Lymphocytes isolated from blood, tonsils, lung tissue and tracheobronchial lymph nodes were analyzed by intracellular cytokine staining (ICS) for IL-17A, IL-10 and TNF-α production after in vitro stimulation with crude capsular extract (CCE) of the APP inoculation strain. This was combined with cell surface staining for the expression of CD4, CD8α and TCR-γδ. Clinical records, microbiological investigations and pathological findings confirmed the induction of a subclinical APP infection. ICS-assays revealed the presence of APP-CCE specific CD4 + CD8α dim IL-17A-producing T cells in blood and lung tissue in most infected animals during the acute and chronic phase of infection and a minor fraction of these cells co-produced TNF-α. APP-CCE specific IL-17A-producing γδ T cells could not be found and APP-CCE specific IL-10-producing CD4 + T cells were present in various organs but only in a few infected animals. The frequency of identified putative Th17 cells (CD4 + CD8α dim IL-17A + ) in lung and blood correlated positively with lung lesion scores and APP-specific antibody titers during the chronic phase. These results suggest a potential role of Th17 cells in the immune pathogenesis of APP infection.

The influence of Actinobacillus pleuropneumoniae infection on tulathromycin pharmacokinetics and lung tissue disposition in pigs.

PubMed

Gajda, A; Bladek, T; Jablonski, A; Posyniak, A

2016-04-01

A tulathromycin concentration and pharmacokinetic parameters in plasma and lung tissue from healthy pigs and Actinobacillus pleuropneumoniae (App)-infected pigs were compared. Tulathromycin was administered intramuscularly (i.m.) to all pigs at a single dose of 2.5 mg/kg. Blood and lung tissue samples were collected during 33 days postdrug application. Tulathromycin concentration in plasma and lung was determined by high-performance liquid chromatography with tandem mass spectrometry (LC-MS/MS) method. The mean maximum plasma concentration (Cmax ) in healthy pigs was 586 ± 71 ng/mL, reached by 0.5 h, while the mean value for Cmax of tulathromycin in infected pigs was 386 ± 97 ng/mL after 0.5 h. The mean maximum tulathromycin concentration in lung of healthy group was calculated as 3412 ± 748 ng/g, detected at 12 h, while in pigs with App, the highest concentration in lung was 3337 ± 937 ng/g, determined at 48 h postdosing. The higher plasma and lung concentrations in pigs with no pulmonary inflammation were observed at the first time points sampling after tulathromycin administration, but slower elimination with elimination half-life t1/2el  = 126 h in plasma and t1/2el  = 165 h in lung, as well as longer drug persistent in infected pigs, was found. © 2015 John Wiley & Sons Ltd.

Minimum inhibitory concentration breakpoints and disk diffusion inhibitory zone interpretive criteria for tilmicosin susceptibility testing against Pasteurella multocida and Actinobacillus pleuropneumoniae associated with porcine respiratory disease.

PubMed

Shryock, Thomas R; Staples, J Mitchell; DeRosa, David C

2002-09-01

Tilmicosin is a novel macrolide antibiotic developed for exclusive use in veterinary medicine. Tilmicosin has been approved as a feed premix to control porcine respiratory disease associated with Pasteurella multocida and Actinobacillus pleuropneumoniae. The development of antimicrobial susceptibility testing guidelines for tilmicosin was predicated on the relationship of clinical efficacy studies that demonstrated a favorable therapeutic outcome, on pharmacokinetic data, and on in vitro test data, as recommended by the National Committee for Clinical Laboratory Standards (NCCLS). The approved breakpoints for the minimum inhibitory concentration dilution testing for both species are resistant, > or = 32 microg/ml, and susceptible, < or = 16 microg/ml. The zone of inhibition interpretive criteria for disk diffusion testing with a 15-microg tilmicosin disk are resistant, < or = 10 mm, and susceptible, > or = 11 mm.

Efficacy of tilmicosin phosphate (Pulmotil premix) in feed for the treatment of a clinical outbreak of Actinobacillus pleuropneumoniae infection in growing-finishing pigs.

PubMed

Hoflack, G; Maes, D; Mateusen, B; Verdonck, M; de Kruif, A

2001-11-01

A double-blind randomized clinical trial was carried out to investigate the efficacy of tilmicosin (Pulmotil premix) for the treatment of a clinical outbreak of Actinobacillus pleuropneumoniae infection in growing-finishing pigs. The effects of tilmicosin administration in the feed at 400 mg/kg and an injection therapy of clinically diseased pigs with long-acting oxytetracycline (Terramycine LA) at 20 mg/kg bodyweight were compared. Both groups, totalling 147 pigs, were compared during a medication period of 15 days and a post-medication period of 11 days by means of different clinical and performance parameters. During the medication period, the tilmicosin group showed a significant advantage with respect to the number of new disease cases (P < 0.01), and a non-significant advantage regarding the number of removed pigs (P = 0.16), the number of sick pigs that recovered (P = 0.27) and the time to recovery (P = 0.42). During the post-medication period, the pigs of the tilmicosin group showed numerical non-significant benefits (P > 0.05) with respect to the clinical parameters. During the overall study period (26 days), the average daily gain and the feed conversion ratio were both significantly (P < 0.01) better in pigs from the tilmicosin group compared with pigs from the oxytetracycline group. This study demonstrated that in-feed medication of tilmicosin at a dosage of 400 mg/kg is efficacious for the treatment of a clinical respiratory disease outbreak of A. pleuropneumoniae infection in growing-finishing pigs. Compared with oxytetracycline injection of clinically diseased pigs, the tilmicosin treatment is particularly beneficial in the prevention of new disease cases while increasing or maintaining the performance of the pigs.

Kinetics of single and dual infection of pigs with swine influenza virus and Actinobacillus pleuropneumoniae.

PubMed

Pomorska-Mól, Małgorzata; Dors, Arkadiusz; Kwit, Krzysztof; Kowalczyk, Andrzej; Stasiak, Ewelina; Pejsak, Zygmunt

2017-03-01

Porcine respiratory disease complex (PRDC) is a common problem in modern pork production worldwide. Pathogens that are amongst other pathogens frequently involved in PRDC etiology are swine influenza virus (SIV) and A. pleuropneumoniae. The effect of dual infection with mentioned pathogens has not been investigated to date. The aim of the present study was to evaluate the kinetics of single and dual infection of pigs with SIV and A. pleuropneumoniae with regard to clinical course, pathogens shedding, lung lesions and early immune response. The most severe symptoms were observed in co-inoculated piglets. The AUC value for SIV shedding was lower in pigs single inoculated with SIV as compared to co-inoculated animals. In contrast, no significant differences were found between A. pleuropneumoniae shedding in single or dual inoculated pigs. Three out of 5 co-inoculated piglets euthanized at 10 dpi were positive against serotype 2 A. pleuropneumonie. All piglets inoculated with SIV developed specific HI antibodies at 10 dpi. In pigs dual inoculated the specific humoral response against SIV was observed earlier, at 7 dpi. The SIV-like lung lesions were more severe in co-inoculated pigs. In the groups inoculated with A. pleuropneumoniae (single or dual) the acute phase protein response was generally stronger than in SIV-single infected group. Co-infection with SIV and A. pleuropneumoniae potentiated the severity of lung lesions caused by SIV and enhanced virus replication in the lung and nasal SIV shedding. Enhanced SIV replication contributed to a more severe clinical course of the disease as well as earlier and higher magnitude immune response (acute phase proteins, HI antibodies) compared to single inoculated pigs. Copyright © 2017 Elsevier B.V. All rights reserved.

Auxotrophic Actinobacillus pleurpneumoniae grows in multispecies biofilms without the need for nicotinamide-adenine dinucleotide (NAD) supplementation.

PubMed

Loera-Muro, Abraham; Jacques, Mario; Avelar-González, Francisco J; Labrie, Josée; Tremblay, Yannick D N; Oropeza-Navarro, Ricardo; Guerrero-Barrera, Alma L

2016-06-27

Actinobacillus pleuropneumoniae is the etiologic agent of porcine contagious pleuropneumonia, which causes important worldwide economic losses in the swine industry. Several respiratory tract infections are associated with biofilm formation, and A. pleuropneumoniae has the ability to form biofilms in vitro. Biofilms are structured communities of bacterial cells enclosed in a self-produced polymer matrix that are attached to an abiotic or biotic surface. Virtually all bacteria can grow as a biofilm, and multi-species biofilms are the most common form of microbial growth in nature. The goal of this study was to determine the ability of A. pleuropneumoniae to form multi-species biofilms with other bacteria frequently founded in pig farms, in the absence of pyridine compounds (nicotinamide mononucleotide [NMN], nicotinamide riboside [NR] or nicotinamide adenine dinucleotide [NAD]) that are essential for the growth of A. pleuropneumoniae. For the biofilm assay, strain 719, a field isolate of A. pleuropneumoniae serovar 1, was mixed with swine isolates of Streptococcus suis, Bordetella bronchiseptica, Pasteurella multocida, Staphylococcus aureus or Escherichia coli, and deposited in 96-well microtiter plates. Based on the CFU results, A. pleuropneumoniae was able to grow with every species tested in the absence of pyridine compounds in the culture media. Interestingly, A. pleuropneumoniae was also able to form strong biofilms when mixed with S. suis, B. bronchiseptica or S. aureus. In the presence of E. coli, A. pleuropneumoniae only formed a weak biofilm. The live and dead populations, and the matrix composition of multi-species biofilms were also characterized using fluorescent markers and enzyme treatments. The results indicated that poly-N-acetyl-glucosamine remains the primary component responsible for the biofilm structure. In conclusion, A. pleuropneumoniae apparently is able to satisfy the requirement of pyridine compounds through of other swine pathogens by

[TLR-4 involvement in pyroptosis of mice with pulmonary inflammation infected by Actinobacillus pleuropneumoniae].

PubMed

Hu, Peipei; Huang, Fushen; Niu, Junchao; Tang, Zhaoshan

2015-05-04

Pyroptosis is a caspase-1 dependent programmed cell death and involves pathogenesis of infectious diseases by releasing many pro-inflammatory cytokines to induced inflammation. TLR-4 plays an important role in mediating pathogenesis of some infectious diseases. In this study, we detected the expression of TLR-4 and some molecules (e. g caspase-1, TNF-α, IL-1β, IL-6, IL-18 ) related with pyroptosis to determine its involvement and mechanisms of pulmonary inflammation in mice infected by A. pleuropneumoniae. Mice were intranasally infected by A. pleuropneumoniae and killed 48 hours post infection. Pulmonary gross lesion and histological pathology by H-E were observed. Expression levels of caspase-1 , caspase-3, TNF-α, IL-1β, IL-6, IL-18, and TLR-4 in lung of mice were detected by RT-PCR and qPCR. Serious pulmonary hemorrhage and inflammation in infected mice were observed. Expression levels of caspase-1, caspase-3, TNF-α, IL-1β, IL-6, IL-18 and TLR-4 increased, and expression levels of caspase-3 were not changed in lung of infected mice. TLR-4 might be involved in pulmonary inflammation of mice infected by A. pleuropneumoniae. After induced by activated TLR-4 some cells in this lesion expressed pro-inflammatory cytokines. These cytokines would induce pulmonary inflammation. This lesion might involve pyroptosis with caspase-1 expression.

Acute and subacute response of iron, zinc, copper and selenium in pigs experimentally infected with Actinobacillus pleuropneumoniae.

PubMed

Humann-Ziehank, Esther; Menzel, Anne; Roehrig, Petra; Schwert, Barbara; Ganter, Martin; Hennig-Pauka, Isabel

2014-10-01

This study was performed to characterise the response of iron (Fe), zinc (Zn), copper (Cu) and selenium (Se) in bacterial-induced porcine acute phase reaction (APR). Twenty piglets were challenged by aerosolic infection with Actinobacillus pleuropneumoniae (A.pp.) serotype 2, ten piglets serving as controls. Blood sampling was done initially and at day 4 and 21 after infection, collection of liver tissue was done at day 21 (autopsy). A.pp.-infection caused fever and respiratory symptoms. APR at day 4 after infection was marked by an increase in total white blood cells, granulocytes and monocytes in whole blood samples and an increase in globulin/albumin ratio (G/A), α2-globulins, C-reactive protein, haptoglobin, ceruloplasmin (Cp), Cu and Se in serum. Concurrently, there was a decrease in haemoglobin (Hb) and packed cell volume (PCV) in whole blood as well as a decrease in albumin, transferrin, total iron binding capacity and Fe in serum and Zn in plasma. The subacute stage at day 21 was characterised by progressively increased concentrations of G/A, β-globulins and γ-globulins reflecting the specific immune reaction. Hb and PCV showed further decreases, all other parameters returned to the initial concentrations. Glutathione peroxidase activity in plasma and liver tissue remained unaffected by A.pp.-infection. The liver concentration (day 21) of Zn was found to be higher, that of Se was lower in the A.pp.-group, whereas hepatic concentrations of Cu and Fe were not affected by A.pp.-infection. In summary, the acute and subacute stages of A.pp.-infection were accurately characterised by the APR-related parameters. Se was only marginally affected by the A.pp.-infection. The elevated plasma Cu concentration may be a side effect of the transient hepatic induction of Cp synthesis. Zn responded, being distinctly reduced in plasma and probably having been sequestered in the liver tissue. Reduction in serum Fe can be regarded as an unspecific defence mechanism in A

Enriched Housing Reduces Disease Susceptibility to Co-Infection with Porcine Reproductive and Respiratory Virus (PRRSV) and Actinobacillus pleuropneumoniae (A. pleuropneumoniae) in Young Pigs

PubMed Central

van Dixhoorn, Ingrid D. E.; Reimert, Inonge; Middelkoop, Jenny; Bolhuis, J. Elizabeth; Wisselink, Henk J.; Groot Koerkamp, Peter W. G.; Kemp, Bas; Stockhofe-Zurwieden, Norbert

2016-01-01

Until today, anti-microbial drugs have been the therapy of choice to combat bacterial diseases. Resistance against antibiotics is of growing concern in man and animals. Stress, caused by demanding environmental conditions, can reduce immune protection in the host, influencing the onset and outcome of infectious diseases. Therefore psychoneuro-immunological intervention may prove to be a successful approach to diminish the impact of diseases and antibiotics use. This study was designed to investigate the effect of social and environmental enrichment on the impact of disease, referred to as “disease susceptibility”, in pigs using a co-infection model of PRRSV and A. pleuropneumoniae. Twenty-eight pigs were raised in four pens under barren conditions and twenty-eight other pigs were raised in four pens under enriched conditions. In the enriched pens a combination of established social and environmental enrichment factors were introduced. Two pens of the barren (BH) and two pens of the enriched housed (EH) pigs were infected with PRRSV followed by A. pleuropneumoniae, the other two pens in each housing treatment served as control groups. We tested if differences in disease susceptibility in terms of pathological and clinical outcome were related to the different housing regimes and if this was reflected in differences in behavioural and immunological states of the animals. Enriched housed pigs showed a faster clearance of viral PRRSV RNA in blood serum (p = 0.014) and histologically 2.8 fold less interstitial pneumonia signs in the lungs (p = 0.014). More barren housed than enriched housed pigs developed lesions in the lungs (OR = 19.2, p = 0.048) and the lesions in the barren housed pigs showed a higher total pathologic tissue damage score (p<0.001) than those in enriched housed pigs. EH pigs showed less stress-related behaviour and differed immunologically and clinically from BH pigs. We conclude that enriched housing management reduces disease susceptibility to

Enriched Housing Reduces Disease Susceptibility to Co-Infection with Porcine Reproductive and Respiratory Virus (PRRSV) and Actinobacillus pleuropneumoniae (A. pleuropneumoniae) in Young Pigs.

PubMed

van Dixhoorn, Ingrid D E; Reimert, Inonge; Middelkoop, Jenny; Bolhuis, J Elizabeth; Wisselink, Henk J; Groot Koerkamp, Peter W G; Kemp, Bas; Stockhofe-Zurwieden, Norbert

2016-01-01

Until today, anti-microbial drugs have been the therapy of choice to combat bacterial diseases. Resistance against antibiotics is of growing concern in man and animals. Stress, caused by demanding environmental conditions, can reduce immune protection in the host, influencing the onset and outcome of infectious diseases. Therefore psychoneuro-immunological intervention may prove to be a successful approach to diminish the impact of diseases and antibiotics use. This study was designed to investigate the effect of social and environmental enrichment on the impact of disease, referred to as "disease susceptibility", in pigs using a co-infection model of PRRSV and A. pleuropneumoniae. Twenty-eight pigs were raised in four pens under barren conditions and twenty-eight other pigs were raised in four pens under enriched conditions. In the enriched pens a combination of established social and environmental enrichment factors were introduced. Two pens of the barren (BH) and two pens of the enriched housed (EH) pigs were infected with PRRSV followed by A. pleuropneumoniae, the other two pens in each housing treatment served as control groups. We tested if differences in disease susceptibility in terms of pathological and clinical outcome were related to the different housing regimes and if this was reflected in differences in behavioural and immunological states of the animals. Enriched housed pigs showed a faster clearance of viral PRRSV RNA in blood serum (p = 0.014) and histologically 2.8 fold less interstitial pneumonia signs in the lungs (p = 0.014). More barren housed than enriched housed pigs developed lesions in the lungs (OR = 19.2, p = 0.048) and the lesions in the barren housed pigs showed a higher total pathologic tissue damage score (p<0.001) than those in enriched housed pigs. EH pigs showed less stress-related behaviour and differed immunologically and clinically from BH pigs. We conclude that enriched housing management reduces disease susceptibility to co

Isolation of Actinobacillus lignieresii and Actinobacillus equuli from laboratory rodents.

PubMed Central

Lentsch, R H; Wagner, J E

1980-01-01

Actinobacillus lignieresii and Actinobacillus equuli were cultured from a total of 36 guinea pigs, rats, and mice. The organisms were isolated from the oropharynx, the conjunctiva, and middle ear. Isolates were initially screened by eight biochemical tests to determine whether they were of the genus Actinobacillus. Actinobacillus spp. were then differentiated by fermentation reactions of nine carbohydrates. In the past, actinobacilli may have been mistakenly identified as Pasteurella spp., especially Pasteurella pneumotropica. The importance of realizing that Actinobacillus spp. are frequently isolated from laboratory rodents was stressed. PMID:7217333

Transcript profiling of the immunological interactions between Actinobacillus pleuropneumoniae serotype 7 and the host by dual RNA-seq.

PubMed

Li, Ping; Xu, Zhiwen; Sun, Xiangang; Yin, Yue; Fan, Yi; Zhao, Jun; Mao, Xiyu; Huang, Jianbo; Yang, Fan; Zhu, Ling

2017-09-12

The complexity of the pathogenic mechanism underlying the host immune response to Actinobacillus pleuropneumonia (App) makes the use of preventive measures difficult, and a more global view of the host-pathogen interactions and new insights into this process are urgently needed to reveal the pathogenic and immune mechanisms underlying App infection. Here, we infected specific pathogen-free Mus musculus with App serotype 7 by intranasal inoculation to construct an acute hemorrhagic pneumonia infection model and isolated the infected lungs for analysis of the interactions by dual RNA-seq. Four cDNA libraries were constructed, and 2428 differentially expressed genes (DEGs) of the host and 333 DEGs of App were detected. The host DEGs were mainly enriched in inflammatory signaling pathways, such as the TLR, NLR, RLR, BCR and TCR signaling pathways, resulting in large-scale cytokine up-regulation and thereby yielding a cytokine cascade for anti-infection and lung damage. The majority of the up-regulated cytokines are involved in the IL-23/IL-17 cytokine-regulated network, which is crucial for host defense against bacterial infection. The DEGs of App were mainly related to the transport and metabolism of energy and materials. Most of these genes are metabolic genes involved in anaerobic metabolism and important for challenging the host and adapting to the anaerobic stress conditions observed in acute hemorrhagic pneumonia. Some of these genes, such as adhE, dmsA, and aspA, might be potential virulence genes. In addition, the up-regulation of genes associated with peptidoglycan and urease synthesis and the restriction of major virulence genes might be immune evasion strategies of App. The regulation of metabolic genes and major virulence genes indicate that the dominant antigens might differ during the infection process and that vaccines based on these antigens might allow establishment of a precise and targeted immune response during the early phase of infection. Through

Detection of PR-39, a porcine host defence peptide, in different cell sub-linages in pigs infected with Actinobacillus pleuropneumoniae.

PubMed

Gabner, S; Egerbacher, M; Gasse, H; Hewicker-Trautwein, M; Höltig, D; Waldmann, K-H; Blecha, F; Saalmüller, A; Hennig-Pauka, I

2017-10-01

Innate immunity is critically important for the outcome of infection in many diseases. It was previously shown that cathelicidin PR-39, an important porcine multifunctional host defence peptide, is elevated in bronchoalveolar lavage fluid and respiratory tract tissue after experimental infection with Actinobacillus pleuropneumoniae (A.pp.). To date, neutrophil polymorphonuclear leukocytes (PMNs) are thought to be the only source of PR-39. The aim of this study was to further characterize PR-39⁺ cells and selected immune cell populations in lung tissue during the peracute (7-10 hours), acute (2 days), reconvalescent (7 days) and chronic (21 days) stages of experimental infection with A.pp. serotype 2. In total, six mock-infected control pigs and 12 infected pigs were examined. Using immunofluorescence double-labeling, antibodies against PR-39 were combined with antibodies against CD3 (T-cells), CD79 (B-cells), Iba1 (activated macrophages), TTF-1 (lung epithelial cells expressing surfactant proteins), macrophage/L1 protein and myeloperoxidase (MPO, cells of the myeloid linage). In the peracute and acute phases of infection, total PR-39⁺ cells and myeloid linage cells increased, whereas CD3⁺ cells and TTF-1⁺ cells decreased. Double labeling revealed that most Macrophage/L1 protein+ cells and to a lesser extent MPO⁺ cells co-expressed PR-39. In addition, few bronchial epithelial cells and type 2 alveolar epithelial cells (both identified with TTF-1) produced PR-39. Occasionally, CD3⁺ T cells expressing PR-39 were seen in infected animals. Taken together, this study identifies cell types, other than PMNs, in lungs of A.pp.-infected pigs that are capable of producing PR-39. In addition, these findings provide further insights into the dynamics of different immune cell populations during A.pp.-infection.

Antibody response of swine to outer membrane components of Haemophilus pleuropneumoniae during infection.

PubMed Central

Rapp, V J; Ross, R F

1986-01-01

Sera from pigs infected with Haemophilus (Actinobacillus) pleuropneumoniae were tested for antibodies to outer membrane proteins (OMPs) of the organism by immunoblotting. Convalescent sera were produced in naturally born, colostrum-fed pigs and in cesarean-derived, colostrum-deprived pigs given H. pleuropneumoniae serotype 5 intranasally twice at 5-week intervals. Sera, collected at weekly intervals, were reacted with Sarkosyl-insoluble, OMP-enriched preparations of H. pleuropneumoniae which had been separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electrophoretically transferred to nitrocellulose. Antibodies were detected to OMPs with an apparent molecular weight of 16,500 (16.5K OMP); to 29K, 38.5K, 43.5K, 45K, 49.5K, and 66.5K OMPs; and to several high-molecular-weight (greater than or equal to 94,000) OMPs, but not to the major 42K OMP. Antibodies to the heat-modifiable OMP (29K/43.5K) and the 38.5K OMP were detected in sera from noninfected pigs. Antibodies were also detected to two broad 54,000- and 95,000-molecular-weight bands which did not stain with Coomassie blue, stained with silver nitrate, resisted proteinase K digestion, and were eliminated by oxidation with sodium metaperiodate. This indicates that the 54,000- and 95,000-molecular-weight bands represent polysaccharide, possibly capsular or lipopolysaccharide immunogens. Adsorption of sera with cells from the homologous serotype 5 strain removed antibodies to the 45K, 49.5K, 66.5K, and greater than or equal to 94K OMPs and to the two polysaccharide bands, indicating that these antibodies were directed primarily to surface-exposed epitopes. When tested with OMP preparations from other serotype 5 strains, heterogeneity was apparent, both in the reactions with OMPs and with the polysaccharide bands. Silver staining of proteinase K-treated, whole-cell lysates from serotype 5 strains also indicated variable expression of the polysaccharide bands. Sera also reacted with OMPs from

Actinobacillus pleuropneumoniae culture supernatant antiviral effect against porcine reproductive and respiratory syndrome virus occurs prior to the viral genome replication and transcription through actin depolymerization.

PubMed

Hernandez Reyes, Yenney; Provost, Chantale; Traesel, Carolina Kist; Jacques, Mario; Gagnon, Carl A

2018-02-01

Recently, the strong antiviral activity of an Actinobacillus pleuropneumoniae (App) culture supernatant against porcine reproductive and respiratory syndrome virus (PRRSV) was discovered. Following this finding, the objective of the present study was to understand how the App culture supernatant inhibits PRRSV replication in its natural targeted host cells, i.e. porcine alveolar macrophages (PAMs). Several assays were conducted with App culture supernatant-treated PRRSV-infected cell lines, such as PAM, St-Jude porcine lung and MARC-145 cells. RT-qPCR assays were used to determine the expression levels of type I and II IFN mRNAs, viral genomic (gRNA) and sub-genomic RNAs (sgRNAs). Proteomic, Western blot and immunofluorescence assays were conducted to determine the involvement of actin filaments in the App culture supernatant antiviral effect.Results/Key findings. Type I and II IFN mRNA expressions were not upregulated by the App culture supernatant. Time courses of gRNA and sgRNA expression levels demonstrated that the App culture supernatant inhibits PRRSV infection before the first viral transcription cycle. Western blot experiments confirmed an increase in the expression of cofilin (actin cytoskeleton dynamics regulator) and immunofluorescence also demonstrated a significant decrease of actin filaments in App culture supernatant-treated PRRSV-infected PAM cells. App culture supernatant antiviral activity was also demonstrated against other PRRSV strains of genotypes I and II. App culture supernatant antiviral effect against PRRSV takes place early during PRRSV infection. Results suggest that App culture supernatant antiviral effect may take place via the activation of cofilin, which induces actin depolymerization and subsequently, probably affects PRRSV endocytosis. Other experiments are needed to fully validate this latest hypothesis.

Galactose-1-phosphate uridyltransferase (GalT), an in vivo-induced antigen of Actinobacillus pleuropneumoniae serovar 5b strain L20, provided immunoprotection against serovar 1 strain MS71.

PubMed

Zhang, Fei; Zhao, Qin; Quan, Keji; Zhu, Zhuang; Yang, Yusheng; Wen, Xintian; Chang, Yung-Fu; Huang, Xiaobo; Wu, Rui; Wen, Yiping; Yan, Qigui; Huang, Yong; Ma, Xiaoping; Han, Xinfeng; Cao, Sanjie

2018-01-01

GALT is an important antigen of Actinobacillus pleuropneumoniae (APP), which was shown to provide partial protection against APP infection in a previous study in our lab. The main purpose of the present study is to investigate GALT induced cross-protection between different APP serotypes and elucidate key mechanisms of the immune response to GALT antigenic stimulation. Bioinformatic analysis demonstrated that galT is a highly conserved gene in APP, widely distributed across multiple pathogenic strains. Homologies between any two strains ranges from 78.9% to 100% regarding the galT locus. Indirect enzyme-linked immunosorbent assay (ELISA) confirmed that GALT specific antibodies could not be induced by inactivated APP L20 or MS71 whole cell bacterin preparations. A recombinant fusion GALT protein derived from APP L20, however has proven to be an effective cross-protective antigen against APP sevorar 1 MS71 (50%, 4/8) and APP sevorar 5b L20 (75%, 6/8). Histopathological examinations have confirmed that recombinant GALT vaccinated animals showed less severe pathological signs in lung tissues than negative controls after APP challenge. Immunohistochemical (IHC) analysis indicated that the infiltration of neutrophils in the negative group is significantly increased compared with that in the normal control (P<0.001) and that in surviving animals is decreased compared to the negative group. Anti-GALT antibodies were shown to mediate phagocytosis of neutrophils. After interaction with anti-GALT antibodies, survival rate of APP challenged vaccinated animals was significantly reduced (P<0.001). This study demonstrated that GALT is an effective cross-protective antigen, which could be used as a potential vaccine candidate against multiple APP serotypes.

Identification of putative adhesins of Actinobacillus suis and their homologues in other members of the family Pasteurellaceae.

PubMed

Bujold, Adina R; MacInnes, Janet I

2015-11-14

Actinobacillus suis disease has been reported in a wide range of vertebrate species, but is most commonly found in swine. A. suis is a commensal of the tonsils of the soft palate of swine, but in the presence of unknown stimuli it can invade the bloodstream, causing septicaemia and sequelae such as meningitis, arthritis, and death. It is genotypically and phenotypically similar to A. pleuropneumoniae, the causative agent of pleuropneumonia, and to other members of the family Pasteurellaceae that colonise tonsils. At present, very little is known about the genes involved in attachment, colonisation, and invasion by A. suis (or related members of the tonsil microbiota). Bioinformatic analyses of the A. suis H91-0380 genome were done using BASys and blastx in GenBank. Forty-seven putative adhesin-associated genes predicted to encode 24 putative adhesins were discovered. Among these are 6 autotransporters, 25 fimbriae-associated genes (encoding 3 adhesins), 12 outer membrane proteins, and 4 additional genes (encoding 3 adhesins). With the exception of 2 autotransporter-encoding genes (aidA and ycgV), both with described roles in virulence in other species, all of the putative adhesin-associated genes had homologues in A. pleuropneumoniae. However, the majority of the closest homologues of the A. suis adhesins are found in A. ureae and A. capsulatus--species not known to infect swine, but both of which can cause systemic infections. A. suis and A. pleuropneumoniae share many of the same putative adhesins, suggesting that the different diseases, tissue tropism, and host range of these pathogens are due to subtle genetic differences, or perhaps differential expression of virulence factors during infection. However, many of the putative adhesins of A. suis share even greater homology with those of other pathogens within the family Pasteurellaceae. Similar to A. suis, these pathogens (A. capsulatus and A. ureae) cause systemic infections and it is tempting to speculate that

21 CFR 522.313b - Ceftiofur hydrochloride.

Code of Federal Regulations, 2014 CFR

2014-04-01

... bacterial pneumonia) associated with Actinobacillus pleuropneumoniae, Pasteurella multocida, Salmonella... treatment of bovine respiratory disease (BRD, shipping fever, pneumonia) associated with Mannheimia...

Differences in Purinergic Amplification of Osmotic Cell Lysis by the Pore-Forming RTX Toxins Bordetella pertussis CyaA and Actinobacillus pleuropneumoniae ApxIA: the Role of Pore Size

PubMed Central

Fiser, Radovan; Linhartova, Irena; Osicka, Radim; Bumba, Ladislav; Hewlett, Erik L.; Benz, Roland; Sebo, Peter

2013-01-01

A large subgroup of the repeat in toxin (RTX) family of leukotoxins of Gram-negative pathogens consists of pore-forming hemolysins. These can permeabilize mammalian erythrocytes (RBCs) and provoke their colloid osmotic lysis (hemolytic activity). Recently, ATP leakage through pannexin channels and P2X receptor-mediated opening of cellular calcium and potassium channels were implicated in cell permeabilization by pore-forming toxins. In the study described here, we examined the role played by purinergic signaling in the cytolytic action of two RTX toxins that form pores of different sizes. The cytolytic potency of ApxIA hemolysin of Actinobacillus pleuropneumoniae, which forms pores about 2.4 nm wide, was clearly reduced in the presence of P2X7 receptor antagonists or an ATP scavenger, such as pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid (PPADS), Brilliant Blue G, ATP oxidized sodium salt, or hexokinase. In contrast, antagonists of purinergic signaling had no impact on the hemolytic potency of the adenylate cyclase toxin-hemolysin (CyaA) of Bordetella pertussis, which forms pores of 0.6 to 0.8 nm in diameter. Moreover, the conductance of pores formed by ApxIA increased with the toxin concentration, while the conductance of the CyaA single pore units was constant at various toxin concentrations. However, the P2X7 receptor antagonist PPADS inhibited in a concentration-dependent manner the exacerbated hemolytic activity of a CyaA-ΔN489 construct (lacking 489 N-terminal residues of CyaA), which exhibited a strongly enhanced pore-forming propensity (>20-fold) and also formed severalfold larger conductance units in planar lipid bilayers than intact CyaA. These results point to a pore size threshold of purinergic amplification involvement in cell permeabilization by pore-forming RTX toxins. PMID:24082076

21 CFR 522.313b - Ceftiofur hydrochloride.

Code of Federal Regulations, 2010 CFR

2010-04-01

... bacterial respiratory disease (swine bacterial pneumonia) associated with Actinobacillus pleuropneumoniae... treatment of bovine respiratory disease (BRD, shipping fever, pneumonia) associated with Mannheimia...

21 CFR 558.261 - Florfenicol.

Code of Federal Regulations, 2013 CFR

2013-04-01

... disease (SRD) associated with Actinobacillus pleuropneumoniae, Pasteurella multocida, Streptococcus suis... streptococcal septicemia associated with Streptococcus iniae Feed as a sole ration for 10 consecutive days to...

21 CFR 558.261 - Florfenicol.

Code of Federal Regulations, 2014 CFR

2014-04-01

... disease (SRD) associated with Actinobacillus pleuropneumoniae, Pasteurella multocida, Streptococcus suis... septicemia associated with Streptococcus iniae Feed as a sole ration for 10 consecutive days to deliver 15 mg...

Recurrent Actinobacillus peritonitis in an otherwise healthy thoroughbred horse.

PubMed

Watts, A E; Johnson, A L; Felippe, M J; Divers, T J

2011-04-01

A Thoroughbred gelding in North America was evaluated for Actinobacillus peritonitis on three different occasions over a 4-year period. At each presentation, peritoneal fluid had an elevated nucleated cell count (220,000-550,000 cells/µL) characterised by non-degenerate neutrophils, no visible bacteria, an elevated total protein (4.6-5.5 g/dL) and bacterial culture yielding Actinobacillus spp. Actinobacillus peritonitis appears to be a regional disease occurring in Australia and less commonly in New Zealand and North America. Recurrence, other than incomplete resolution, has not been previously reported. This case highlights the classical presentation, response to therapy and excellent prognosis despite the alarmingly abnormal peritoneal fluid characteristic of Actinobacillus peritonitis and questions the role of parasite migration in the pathogenesis. Finally, this case is remarkable because Actinobacillus peritonitis was recurrent over several years in an otherwise normal horse. © 2011 The Authors. Australian Veterinary Journal © 2011 Australian Veterinary Association.

Actinobacillus equuli Septicemia: an Unusual Zoonotic Infection

PubMed Central

Ashhurst-Smith, Christopher; Norton, Robert; Thoreau, Wendy; Peel, Margaret M.

1998-01-01

We describe the isolation of Actinobacillus equuli from the blood of a 53-year-old butcher with septicemia. This species of the genus Actinobacillus is primarily associated with animals and animal diseases, especially septicemia in foals. This is the first report of the isolation of A. equuli from a human with septicemia. PMID:9705442

Classification of avian haemolytic Actinobacillus-like organisms (Bisgaard taxon 26) associated with anseriforme birds as Actinobacillus anseriformium sp. nov.

PubMed

Bisgaard, M; Christensen, H

2012-02-01

Avian haemolytic Actinobacillus-like organisms have tentatively been named Bisgaard taxon 26. Phenotypic information has been published on 65 strains of this taxon. In the current study, 31 isolates were selected for genotypic characterization. Thirty strains had the same rpoB sequence and only one strain diverged in 1 nt. The highest rpoB similarity to members of other taxa was 89.7 % to the type strain of Actinobacillus equuli subsp. haemolyticus and the similarity to the type strain of the type species, Actinobacillus lignieresii, was 88.2 %. The lowest 16S rRNA gene sequence similarity between strains of the group was determined in previous investigations to be 99.6 % and the highest similarities of 96.4 and 96.2 % outside the group were obtained to the reference strain of Actinobacillus genomospecies 2 and to the type strain of A. equuli subsp. equuli, respectively; 95.8-95.3 % similarity was obtained with the type strain of A. lignieresii. recN gene sequence similarities within the group were from 99.5 % (strains F66(T) and F64) to 99.8 % (strains F66(T) and F67) corresponding to genome similarities of 93.9-94.6 %, which are near the upper limit for species compared with other members of the Pasteurellaceae. The highest recN similarity outside the group (83.4 %) was observed to the type strain of Actinobacillus capsulatus, whereas the similarity to the type strain of A. lignieresii was 80.9 %, corresponding to genome similarities of 57.7 and 52.0 %, respectively. All isolates meet the phenotypic characters outlined for Actinobacillus (urease-, phosphatase- and porphyrin-positive, indole-negative, acid production from fructose, sucrose, maltose and dextrin). β-Haemolysis of bovine blood is observed and isolates may demonstrate in vitro satellitic growth, referred to as V-factor or NAD requirement. Isolates have been obtained from the upper respiratory tract of web-footed birds in which they may cause sinusitis, conjunctivitis and

Clinical Significance and Taxonomy of Actinobacillus hominis

PubMed Central

Friis-Møller, Alice; Christensen, Jens Jørgen; Fussing, Vivian; Hesselbjerg, Annemarie; Christiansen, Jytte; Bruun, Brita

2001-01-01

Clinical findings in 36 immunosuppressed patients with lower respiratory tract infection or bacteremia with Actinobacillus hominis are described. Animal contact was only recorded for three patients; nine patients died despite appropriate antimicrobial treatment. Although infections with this microorganism seem to be rare, the fact that 37 of 46 strains characterized in this study have been found in Copenhagen indicates that under-reporting may occur. A. hominis is phenotypically relatively homogeneous but can be difficult to differentiate from other Actinobacillus species unless extensive biochemical testing is performed. Mannose-positive strains of A. hominis are especially difficult to differentiate from A. equuli. Attempts to identify A. hominis by automatic identification systems may lead to misidentifications. Ribotyping and DNA-DNA hybridization data show that A. hominis is a homogeneous species clearly separated from other species within the genus Actinobacillus. PMID:11230406

COMPARISON OF SELECTED ACTINOBACILLUS SPECIES WITH A HEMOLYTIC VARIETY OF ACTINOBACILLUS FROM IRRADIATED SWINE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wetmore, P.W.; Thiel, J.F.; Herman, Y.F.

1963-11-01

In studies on the effects of irradiation in swine, microorganisms with colonial characteristics of the genus Actinobacillus were isolated from the blood and/or synovial fluid of inflamed hocks of four adult pigs and one piglet. These cultures were hemolytic, and otherwise varied little physiologically from available strains of Actinobacillus lignle resii and A. equuli. Therefore, attempts were made to further characterize these organisms isolnted from swine blood and synovial fluid, and to examine their biological similarities to strains of A. equuli, A. lignieresii, and A. mallei. Four of the isolates were from the blood of adult swine killed by anmore » atomic explosion and the fifth was from a lethally irradiated young pig. These isolates were serologically related to strains of A. equuli and A. lignieresii; the latter species comprised a serologically heterogeneous group with irtergrading antigenic properties. Although A. equuli and A. lignieresii are classified in the literature as separate species on the basis of the ability of the former but not the latter to produce nitrite from nitrate, this separate speciation could not be confirmed, and it is proposed that the taxonomic designation equuli be discortinued. Also, A. Mallei strains were very different from other Actinobacillus strains, and it is suggested that the species A. mallei be designated as Pseudomonas mallei. In virulence studies, the actinobacflli isolated from irradiated swine did not produce evident disease when 1 billion cells were injected intraperitoneally in guinea pigs, but 500 million cells injected irto mice caused 35% mortality in 24 hr. (BBB)« less

Rhodococcus equi pleuropneumonia in an adult horse

PubMed Central

Vengust, Modest; Stæmpfli, Henry; Prescott, John F.

2002-01-01

A 10-year-old warmblood gelding was evaluated for intermittent pyrexia, dullness, weight loss, and progressive respiratory disease. Multifocal necrotic pneumonia and pleuritis due to Rhodococcus equi infection was diagnosed. Case management is discussed, as well as factors that may have led to this rare cause of pleuropneumonia in an adult horse. PMID:12240529

Application of Enrofloxacin and Orbifloxacin Disks Approved in Japan for Susceptibility Testing of Representative Veterinary Respiratory Pathogens

PubMed Central

HARADA, Kazuki; USUI, Masaru; ASAI, Tetsuo

2014-01-01

ABSTRACT In this study, susceptibilities of Pasteurella multocida, Mannheimia haemolytica and Actinobacillus pleuropneumoniae to enrofloxacin and orbifloxacin were tested using an agar diffusion method with the commercial disks and a broth microdilution method. Good correlation between the 2 methods for enrofloxacin and orbifloxacin was observed for P. multocida (r = −0.743 and −0.818, respectively), M. haemolytica (r = −0.739 and −0.800, respectively) and A. pleuropneumoniae (r = −0.785 and −0.809, respectively). Based on the Clinical and Laboratory Standards Institute interpretive criteria for enrofloxacin, high-level categorical agreement between the 2 methods was found for P. multocida (97.9%), M. haemolytica (93.8%) and A. pleuropneumoniae (92.0%). Our findings indicate that the tested commercial disks can be applied for susceptibility testing of veterinary respiratory pathogens. PMID:25008965

A novel taxon within the genus Actinobacillus isolated from alpaca (Vicugna pacos) in the United Kingdom.

PubMed

Hunt, Brian; Bidewell, Cornelia; Koylass, Mark S; Whatmore, Adrian M

2013-05-03

Members of the genus Actinobacillus comprise a diverse group of bacteria associated with mammals and birds including both pathogens and commensals. Here we describe the isolation of a previously undescribed Actinobacillus-like organism from seven epidemiologically unrelated infections of alpaca. The isolates are phenotypically and genotypically distinct from any previously described Actinobacillus species but 16S rRNA analysis unequivocally places the isolates as a novel lineage within the Actinobacillus sensu stricto. The clinical relevance of the organism requires further study however isolation in pure culture from organs of some cases suggests it may be associated with septicaemia in juvenile alpaca. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Acquisition of haemoglobin-bound iron by strains of the Actinobacillus minor/"porcitonsillarum" complex.

PubMed

Arya, Gitanjali; Niven, Donald F

2011-03-24

Members of the Actinobacillus minor/"porcitonsillarum" complex are common inhabitants of the swine respiratory tract. Although avirulent or of low virulence for pigs, these organisms, like pathogens, do grow in vivo and must, therefore, be able to acquire iron within the host. Here, we investigated the abilities of six members of the A. minor/"porcitonsillarum" complex to acquire iron from transferrin and various haemoglobins. Using growth assays, all six strains were shown to acquire iron from porcine, bovine and human haemoglobins but not from porcine transferrin. Analyses of whole genome sequences revealed that A. minor strains NM305(T) and 202, unlike the swine-pathogenic actinobacilli, A. pleuropneumoniae and A. suis, lack not only the transferrin-binding protein genes, tbpA and tbpB, but also the haemoglobin-binding protein gene, hgbA. Strains NM305(T) and 202, however, were found to possess other putative haemin/haemoglobin-binding protein genes that were predicted to encode mature proteins of ∼ 72 and ∼ 75 kDa, respectively. An affinity procedure based on haemin-agarose allowed the isolation of ∼ 65 and ∼ 67 kDa iron-repressible outer membrane polypeptides from membranes derived from strains NM305(T) and 202, respectively, and mass spectrometry revealed that these polypeptides were the products of the putative haemin/haemoglobin-binding protein genes. PCR approaches allowed the amplification and sequencing of homologues of both haemin/haemoglobin-binding protein genes from each of the other four strains, strains 33PN and 7ATS of the A. minor/"porcitonsillarum" complex and "A. porcitonsillarum" strains 9953L55 and 0347, suggesting that such proteins are involved in the utilization of haemoglobin-bound iron, presumably as surface receptors, by all six strains investigated. Copyright © 2010 Elsevier B.V. All rights reserved.

Isolation of Actinobacillus suis from a cat's lung.

PubMed Central

Daignault, D; Chouinard, L; Møller, K; Ahrens, P; Messier, S; Higgins, R

1999-01-01

Actinobacillus suis has been isolated from the lungs of 9-month-old cat. The bacterium was characterized biochemically as well as genetically, and its sensitivity profile to different antimicrobial agents was established. The role of this isolate in the cat's condition is discussed. PMID:9919368

Phylogenomic and Molecular Demarcation of the Core Members of the Polyphyletic Pasteurellaceae Genera Actinobacillus, Haemophilus, and Pasteurella

PubMed Central

Naushad, Sohail; Adeolu, Mobolaji; Goel, Nisha; Khadka, Bijendra; Al-Dahwi, Aqeel; Gupta, Radhey S.

2015-01-01

The genera Actinobacillus, Haemophilus, and Pasteurella exhibit extensive polyphyletic branching in phylogenetic trees and do not represent coherent clusters of species. In this study, we have utilized molecular signatures identified through comparative genomic analyses in conjunction with genome based and multilocus sequence based phylogenetic analyses to clarify the phylogenetic and taxonomic boundary of these genera. We have identified large clusters of Actinobacillus, Haemophilus, and Pasteurella species which represent the “sensu stricto” members of these genera. We have identified 3, 7, and 6 conserved signature indels (CSIs), which are specifically shared by sensu stricto members of Actinobacillus, Haemophilus, and Pasteurella, respectively. We have also identified two different sets of CSIs that are unique characteristics of the pathogen containing genera Aggregatibacter and Mannheimia, respectively. It is now possible to demarcate the genera Actinobacillus sensu stricto, Haemophilus sensu stricto, and Pasteurella sensu stricto on the basis of discrete molecular signatures. The other members of the genera Actinobacillus, Haemophilus, and Pasteurella that do not fall within the “sensu stricto” clades and do not contain these molecular signatures should be reclassified as other genera. The CSIs identified here also provide useful diagnostic targets for the identification of current and novel members of the indicated genera. PMID:25821780

First Human Case of Meningitis and Sepsis in a Child Caused by Actinobacillus suis or Actinobacillus equuli.

PubMed

Montagnani, Carlotta; Pecile, Patrizia; Moriondo, Maria; Petricci, Patrizia; Becciani, Sabrina; Chiappini, Elena; Indolfi, Giuseppe; Rossolini, Gian Maria; Azzari, Chiara; de Martino, Maurizio; Galli, Luisa

2015-06-01

We report the first human case of meningitis and sepsis caused in a child by Actinobacillus suis or A. equuli, a common opportunistic pathogen of swine or horses, respectively. Identification was performed by matrix-assisted laser desorption ionization-time of flight mass spectrometry and real-time PCR assay. A previous visit to a farm was suspected as the source of infection. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Cerebral hemorrhage in infective endocarditis caused by Actinobacillus actinomycetemcomitans.

PubMed

Lin, Gen-Min; Chu, Kai-Min; Juan, Chun-Jung; Chang, Feng-Yee

2007-11-01

Cerebral hemorrhage occurs rarely in endocarditis caused by Actinobacillus actinomycetemcomitans. A 51-year-old man with a prosthetic mitral valve, who had been prophylactically treated (7 years) with warfarin, presented with intermittent fever. On admission, a Levine grade II/VI systolic cardiac murmur was detected. A transthoracic echocardiogram was negative for valve vegetation. Cefepime (1 g every 8 hours) was administered intravenously. On day 4, culturing of Gram-negative bacilli from blood and a transesophageal echocardiogram revealed a small oscillating filament attached to lateral mitral prosthetic ring on the atrial side. Ceftriaxone (2 g once daily) was started. Gait instability and left-side weakness developed abruptly 2 weeks later; brain magnetic resonance imaging revealed a hematoma over the right parietal-occipital lobe. Ceftriaxone was adjusted to 2 g every 12 hours. Actinobacillus actinomycetemcomitans was identified 3 weeks later. Recovery was achieved, with significant interval improvement and resolution of the cerebral lesions evident on CT.

Species-specific multiplex PCR for the diagnosis of Brucella ovis, Actinobacillus seminis, and Histophilus somni infection in rams

PubMed Central

2013-01-01

Background Infectious ovine epididymitis results in substantial economic losses worldwide due to reproductive failure and culling of breeders. The most common causative agents of these infections are Brucella ovis, Actinobacillus seminis, and Histophilus somni. The aim of this study was to develop a multiplex PCR assay for simultaneous detection of Brucella ovis, Actinobacillus seminis, and Histophilus somni with species-specific primers applied to biological samples for molecular diagnosis of these infections. Results The multiplex assay was capable of detecting B. ovis, A. seminis, and H. somni DNA simultaneously from genomic bacterial DNA samples and pool of semen samples from experimentally infected rams. The method was highly specific since it did not amplify DNA from other bacterial species that can potentially cause epididymitis in rams as well as species phylogenetically related to B. ovis. All negative control samples were negative in PCR multiplex assay. Urine can be used as an alternative to semen samples. Conclusions The species-specific multiplex PCR assay developed in this study can be successfully used for the detection of three of the most common bacterial causes of ovine epididymitis. PMID:23514236

Specific Immune Response of Mares and their Newborn Foals to Actinobacillus spp. Present in the Oral Cavity

PubMed Central

Sternberg, S

2001-01-01

Oral swab samples, serum and colostrum was taken from 15 mares and 14 of their foals, within 24 h of birth. The presence of antibody against Actinobacillus spp. isolated from the oral cavity was investigated using agar gel immunodiffusion. Antibodies against 48 out of the 77 Actinobacillus isolates from all horses in the study were present in the respective sera of 13 mares and 9 foals. In 11 mother-foal pairs, the antibody content of the foal serum was similar to that of the mare, and in 9 cases this was reflected in the antibody content of colostrum from the mare. The results indicate that an immune response to Actinobacillus spp. colonising the oral cavity is present in many adult horses and that this immune response can be transferred from mother to foal via colostrum. PMID:11503368

First isolation of Actinobacillus genomospecies 2 in Japan.

PubMed

Murakami, Miyuki; Shimonishi, Yoshimasa; Hobo, Seiji; Niwa, Hidekazu; Ito, Hiroya

2016-05-03

We describe here the first isolation of Actinobacillus genomospecies 2 in Japan. The isolate was found in a septicemic foal and characterized by phenotypic and genetic analyses, with the latter consisting of 16S rDNA nucleotide sequence analysis plus multilocus sequence analysis using three housekeeping genes, recN, rpoA and thdF, that have been proposed for use as a genomic tool in place of DNA-DNA hybridization.

First isolation of Actinobacillus genomospecies 2 in Japan

PubMed Central

MURAKAMI, Miyuki; SHIMONISHI, Yoshimasa; HOBO, Seiji; NIWA, Hidekazu; ITO, Hiroya

2015-01-01

We describe here the first isolation of Actinobacillus genomospecies 2 in Japan. The isolate was found in a septicemic foal and characterized by phenotypic and genetic analyses, with the latter consisting of 16S rDNA nucleotide sequence analysis plus multilocus sequence analysis using three housekeeping genes, recN, rpoA and thdF, that have been proposed for use as a genomic tool in place of DNA-DNA hybridization. PMID:26668165

Randomised controlled field study to evaluate the efficacy and clinical safety of a single 8 mg/kg injectable dose of marbofloxacin compared with one or two doses of 7.5 mg/kg injectable enrofloxacin for the treatment of Actinobacillus pleuropneumoniae infections in growing-fattening pigs in Europe.

PubMed

Grandemange, Erik; Perrin, Pierre-Alexandre; Cvejic, Dejean; Haas, Miriam; Rowan, Tim; Hellmann, Klaus

2017-01-01

Acute outbreaks of Actinobacillus pleuropneumoniae (APP) require rapid, effective, parenteral antimicrobial treatment. The efficacy and safety of a single, short-acting, high dose of marbofloxacin (Forcyl® swine 160 mg/mL) compared with 1 or 2 doses of 7.5 mg/kg enrofloxacin in APP outbreaks in European farms was studied. A controlled, randomised block, blinded, multicentre, field study was conducted on four farms with acute respiratory disease associated with APP. Animals with clinical signs of respiratory disease were allocated similarly to intramuscular treatments of either a single dose 8 mg/kg marbofloxacin on day 0 or, 7.5 mg/kg enrofloxacin (Baytril 1nject®) on day 0 and again on day 2, if clinical signs had not improved. The results were similar for intention to treat (242 pigs) and per protocol populations (239 pigs). On day 0, all pigs had pyrexia (means, 40.6 °C), moderate to severe clinical signs (depression, cough, dyspnoea). Following treatment, animals improved rapidly and on day 7, clinical signs were absent or mild in all pigs and mean temperatures for each treatment were <39.5 °C ( P  > 0.05). The primary efficacy criterion, animals cured, for marbofloxacin and enrofloxacin was 81.8 and 81.4% on day 7, and 84.2 and 82.2% on day 21, respectively. Results for cure, respiratory disease removals and mortalities, and relapses were compared using confidence intervals and confirmed that marbofloxacin was non-inferior to enrofloxacin ( P  > 0.05). There were no significant treatment differences in live weight gains, adverse events and injection site reactions (<2.5% animals) ( P  > 0.05). Significantly more animals developed concurrent disorders in the enrofloxacin (7.5%) than marbofloxacin (0.0%) group ( P  < 0.01). On day 0, the MIC 90 values of APP for marbofloxacin and enrofloxacin were 0.06 μg/mL for APP, less than the clinical breakpoints. Marbofloxacin (single dose of 8 mg/kg) and enrofloxacin (1 or 2 doses of 7.5�

Mesenteric lymphangitis and sepsis due to RTX toxin-producing Actinobacillus spp in 2 foals with hypothyroidism-dysmaturity syndrome.

PubMed

Löhr, C V; Polster, U; Kuhnert, P; Karger, A; Rurangirwa, F R; Teifke, J P

2012-07-01

Actinobacillus suis-like organisms (ASLOs) have been isolated from the genital, respiratory, and digestive tracts of healthy adult horses, horses with respiratory disease, and septic foals. Two foals with congenital hypothyroidism-dysmaturity syndrome from separate farms developed ASLO infection. At necropsy, both had contracted carpal flexor tendons, thyroid hyperplasia, and thrombotic and necrotizing mesenteric lymphangitis and lymphadenitis; one foal also had mandibular prognathism. Numerous ASLOs were isolated from tissues from both foals, including intestine. Biochemical testing and mass spectrometric analysis of the two Actinobacillus isolates did not allow unequivocal identification. Comparative genetic analysis was done on these and similar isolates, including phylogeny based on 16S rRNA, rpoB and recN genes, as well as RTX (repeat in toxin) toxin typing of apxIA-apxIVA and aqxA genes. One isolate was identified as Actinobacillus suis sensu stricto, based on the presence of apxIA and apxIIA but not aqxA, whereas the other isolate had aqxA but neither apxIA nor apxIIA, consistent with A equuli ssp haemolyticus. Based on genotypic analysis of the isolates included for comparison, 3 of 3 equine ASLOs and 2 of 5 A equuli isolates were reclassified as A equuli subsp haemolyticus, emphasizing the importance of toxin genotyping in accurate classification of actinobacilli.

Crystallization and preliminary X-ray crystallographic analysis of MacA from Actinobacillus actinomycetemcomitans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piao, Shunfu; Xu, Yongbin; Ha, Nam-Chul, E-mail: hnc@pusan.ac.kr

2008-05-01

A periplasmic membrane-fusion protein MacA from Actinobacillus actinomycetemcomitans, an essential component of the multidrug efflux pump in Gram-negative bacteria, was crystallized. Periplasmic membrane-fusion proteins (MFPs) are an essential component of the multidrug efflux pump in Gram-negative bacteria. They play a crucial role in bridging the outer membrane porin TolC and two distinct types of inner membrane transporters. The MFP MacA bridges the inner membrane ABC-type multidrug transporter MacB and the outer membrane porin TolC. MacA from the pathogenic bacterium Actinobacillus actinomycetemcomitans was expressed in Escherichia coli B834 (DE3) and the recombinant protein was purified using Ni–NTA affinity, Q anion-exchange andmore » gel-filtration chromatography. The purified MacA protein was crystallized using the vapour-diffusion method. A MAD diffraction data set was collected to a resolution of 3.0 Å at 100 K. The crystal belongs to space group P622, with unit-cell parameters a = b = 109.2, c = 255.4 Å, α = β = 90, γ = 120°, and contains one molecule in the asymmetric unit.« less

PCR Methods for Rapid Identification and Characterization of Actinobacillus seminis Strains

PubMed Central

Appuhamy, S.; Coote, J. G.; Low, J. C.; Parton, R.

1998-01-01

Twenty-four isolates of Actinobacillus seminis were typed by PCR ribotyping, repetitive extragenic palindromic element (REP)-based PCR, and enterobacterial repetitive intergenic consensus (ERIC)-based PCR. Five types were distinguished by REP-PCR, and nine types were distinguished by ERIC-PCR. PCR ribotyping produced the simplest pattern and could be useful for identification of A. seminis and for its differentiation from related species. REP- and ERIC-PCR could be used for strain differentiation in epidemiological studies of A. seminis. PMID:9508320

Actinobacillus endocarditis associated with hypertrophic cardiomyopathy

PubMed Central

Jorge, Vanda Cristina; Araújo, Ana Carolina; Grilo, Ana; Noronha, Carla; Panarra, António; Riso, Nuno; Vaz Riscado, Manuel

2012-01-01

Infective endocarditis can be associated with complex clinical presentations, sometimes with a difficult multi-disciplinary management. Actinobacillus actinomycetemcomitans belongs to the Haemophilus species, Actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens and Kingella species group, responsible for 5% to 10% of infective endocarditis in native heart valves. These organisms have slow fastidious growth pattern, often associated with negative cultures, and cause systemic embolism with abscess formation. The authors present the case of a 59-year-old man, admitted due to fever of unknown origin, with a personal history of obstructive hypertrophic cardiomyopathy and recent dental manipulation. The diagnosis of mitral valve’s endocarditis was established after a transoesophageal ecocardiography, with a late isolation of A actinomycetemcomitans in blood culture. Despite the institution of antibiotic therapy, the patient suffered from multiple episodes of septic embolism: skin, mucosae, cerebral abscesses, spondylodiscitis and uveitis. He was submitted to heart surgery with miectomy and replacement of the native mitral valve by a mechanical prosthesis, while on antibiotics. PMID:22891010

Production of succinic acid from oil palm empty fruit bunch cellulose using Actinobacillus succinogenes

NASA Astrophysics Data System (ADS)

Pasma, Satriani Aga; Daik, Rusli; Maskat, Mohamad Yusof

2013-11-01

Succinic acid is a common metabolite in plants, animals and microorganisms. It has been used widely in agricultural, food and pharmaceutical industries. Enzymatic hydrolysate glucose from oil palm empty fruit bunch (OPEFB) cellulose was used as a substrate for succinic acid production using Actinobacillus succinogenes. Using cellulose extraction from OPEFB can enhance the production of glucose as a main substrate for succinic acid production. The highest concentration of glucose produced from enzymatic hydrolysis is 167 mg/mL and the sugar recovery is 0.73 g/g of OPEFB. By optimizing the culture medium for succinic acid fermentation with enzymatic hydrolysate of OPEFB cellulose, the nitrogen sources could be reduced to just only 2.5 g yeast extract and 2.5 g corn step liquor. Batch fermentation was carried out using enzymatic hydrolysate of OPEFB cellulose with yeast extract, corn steep liquor and the salts mixture, 23.5 g/L succinic acid was obtained with consumption of 72 g/L glucose in enzymatic hydrolysate of OPEFB cellulose at 38 hours and 37°C. This study suggests that enzymatic hydrolysate of OPEFB cellulose maybe an alternative substrate for the efficient production of succinic acid by Actinobacillus succinogenes.

Swine Influenza Virus and Association with the Porcine Respiratory Disease Complex in Pig Farms in Southern Brazil.

PubMed

Schmidt, C; Cibulski, S P; Andrade, C P; Teixeira, T F; Varela, A P M; Scheffer, C M; Franco, A C; de Almeida, L L; Roehe, P M

2016-05-01

Despite the putative endemic status of swine influenza A virus (swIAV) infections, data on the occurrence of swine influenza outbreaks are scarce in Brazil. The aim of this study was to detect and subtype swIAVs from six outbreaks of porcine respiratory disease complex (PRDC) in southern Brazil. Nasal swabs were collected from 66 piglets with signs of respiratory disease in six herds. Lung tissue samples were collected from six necropsied animals. Virus detection was performed by PCR screening and confirmed by virus isolation and hemagglutination (HA). Influenza A subtyping was performed by a real-time reverse transcriptase PCR (rRT-PCR) to detect the A(H1N1)pdm09; other swIAV subtypes were determined by multiplex RT-PCR. In lung tissues, the major bacterial and viral pathogens associated with PRDC (Pasteurella multocida, Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, Haemophilus parasuis and PCV2) were investigated. In some affected pigs, clinico-pathological evaluations were conducted. Influenza A was detected by screening PCR in 46 of 66 swab samples and from five of six lungs. Virus was recovered from pigs of all six herds. Subtype A(H1N1)pdm09 was detected in four of six herds and H1N2 in the other two herds. In lung tissues, further agents involved in PRDC were detected in all cases; Pasteurella multocida was identified in five of six samples and Mycoplasma hyopneumoniae in three of six. Actinobacillus pleuropneumoniae (1/6), Haemophilus parasuis (1/6) and PCV2 (1/6) were also detected. These findings indicate that subtypes A(H1N1)pdm09 and H1N2 were present in pigs in southern Brazil and were associated with PRDC outbreaks. © 2015 Blackwell Verlag GmbH.

Significance of CO2 donor on the production of succinic acid by Actinobacillus succinogenes ATCC 55618

PubMed Central

2011-01-01

Background Succinic acid is a building-block chemical which could be used as the precursor of many industrial products. The dissolved CO2 concentration in the fermentation broth could strongly regulate the metabolic flux of carbon and the activity of phosphoenolpyruvate (PEP) carboxykinase, which are the important committed steps for the biosynthesis of succinic acid by Actinobacillus succinogenes. Previous reports showed that succinic acid production could be promoted by regulating the supply of CO2 donor in the fermentation broth. Therefore, the effects of dissolved CO2 concentration and MgCO3 on the fermentation process should be investigated. In this article, we studied the impacts of gaseous CO2 partial pressure, dissolved CO2 concentration, and the addition amount of MgCO3 on succinic acid production by Actinobacillus succinogenes ATCC 55618. We also demonstrated that gaseous CO2 could be removed when MgCO3 was fully supplied. Results An effective CO2 quantitative mathematical model was developed to calculate the dissolved CO2 concentration in the fermentation broth. The highest succinic acid production of 61.92 g/L was obtained at 159.22 mM dissolved CO2 concentration, which was supplied by 40 g/L MgCO3 at the CO2 partial pressure of 101.33 kPa. When MgCO3 was used as the only CO2 donor, a maximal succinic acid production of 56.1 g/L was obtained, which was just decreased by 7.03% compared with that obtained under the supply of gaseous CO2 and MgCO3. Conclusions Besides the high dissolved CO2 concentration, the excessive addition of MgCO3 was beneficial to promote the succinic acid synthesis. This was the first report investigating the replaceable of gaseous CO2 in the fermentation of succinic acid. The results obtained in this study may be useful for reducing the cost of succinic acid fermentation process. PMID:22040346

INCIDENCE AND DETECTION OF PLEUROPNEUMONIA-LIKE ORGANISMS IN CELL CULTURES BY FLUORESCENT ANTIBODY AND CULTURAL PROCEDURES1

PubMed Central

Barile, Michael F.; Malizia, Walter F.; Riggs, Donald B.

1962-01-01

Barile, Michael F. (National Institutes of Health, Bethesda, Md.), Walter F. Malizia, and Donald B. Riggs. Incidence and detection of pleuropneumonia-like organisms in cell cultures by fluorescent antibody and cultural procedures. J. Bacteriol. 84:130–136. 1962—A total of 102 tissue-cell cultures from 17 separate laboratories was examined for pleuropneumonia-like organisms (PPLO) by the fluorescent antibody and cultural procedures. PPLO were isolated from 48 of the 49 tissue-cell cultures found positive for PPLO by the fluorescent antibody procedure, and results of the two procedures agreed in 101 of the 102 (99%) cases. PPLO were isolated from none of 10 primary-cell cultures prepared from six animal species and from 48 of 92 (52%) continuous-cell cultures prepared from eight animal species. Cells grown in media containing antibiotics were more frequently contaminated with PPLO (72%) than cells grown in antibiotic-free media (7%). Cultures (91%) from tissue-culture-producing laboratories and cultures (76%) used for propagation of microorganisms were contaminated with PPLO, although none used for tissue-culture metabolic studies was contaminated. In addition, our findings support the view that PPLO contamination of cell cultures is probably owing to bacterial contaminants which revert to L forms in the presence of antibiotics. Images PMID:13865001

In vitro activity and rodent efficacy of clinafloxacin for bovine and swine respiratory disease.

PubMed

Sweeney, Michael T; Quesnell, Rebecca; Tiwari, Raksha; Lemay, Mary; Watts, Jeffrey L

2013-01-01

Clinafloxacin is a broad-spectrum fluoroquinolone that was originally developed and subsequently abandoned in the late 1990s as a human health antibiotic for respiratory diseases. The purpose of this study was to investigate the activity of clinafloxacin as a possible treatment for respiratory disease in cattle and pigs. Minimum inhibitory concentration (MIC) values were determined using Clinical and Laboratory Standards Institute recommended procedures with recent strains from the Zoetis culture collection. Rodent efficacy was determined in CD-1 mice infected systemically or intranasally with bovine Mannheimia haemolytica or Pasteurella multocida, or swine Actinobacillus pleuropneumoniae, and administered clinafloxacin for determination of ED50 (efficacious dose-50%) values. The MIC90 values for clinafloxacin against bovine P. multocida, M. haemolytica, Histophilus somni, and M. bovis were 0.125, 0.5, 0.125, and 1 μg/ml, respectively, and the MIC90 values against swine P. multocida, A. pleuropneumoniae, S. suis, and M. hyopneumoniae were í0.03, í0.03, 0.125, and í0.008 μg/ml, respectively. Efficacy in mouse models showed average ED50 values of 0.019 mg/kg/dose in the bovine M. haemolytica systemic infection model, 0.55 mg/kg in the bovine P. multocida intranasal lung challenge model, 0.08 mg/kg/dose in the bovine P. multocida systemic infection model, and 0.7 mg/kg/dose in the swine A. pleuropneumoniae systemic infection model. Clinafloxacin shows good in vitro activity and efficacy in mouse models and may be a novel treatment alternative for the treatment of respiratory disease in cattle and pigs.

Effects of Enrofloxacin on Porcine Phagocytic Function

PubMed Central

Schoevers, E. J.; van Leengoed, L. A. M. G.; Verheijden, J. H. M.; Niewold, T. A.

1999-01-01

The interaction between enrofloxacin and porcine phagocytes was studied with clinically relevant concentrations of enrofloxacin. Enrofloxacin accumulated in phagocytes, with cellular concentration/extracellular concentration ratios of 9 for polymorphonuclear leukocytes (PMNs) and 5 for alveolar macrophages (AMs). Cells with accumulated enrofloxacin brought into enrofloxacin-free medium released approximately 80% (AMs) to 90% (PMNs) of their enrofloxacin within the first 10 min, after which no further release was seen. Enrofloxacin affected neither the viability of PMNs and AMs nor the chemotaxis of PMNs at concentrations ranging from 0 to 10 μg/ml. Enrofloxacin (0.5 μg/ml) did not alter the capability of PMNs and AMs to phagocytize fluorescent microparticles or Actinobacillus pleuropneumoniae, Pasteurella multocida, and Staphylococcus aureus. Significant differences in intracellular killing were seen with enrofloxacin at 5× the MIC compared with that for controls not treated with enrofloxacin. PMNs killed all S. aureus isolates in 3 h with or without enrofloxacin. Intracellular S. aureus isolates in AMs were less susceptible than extracellular S. aureus isolates to the bactericidal effect of enrofloxacin. P. multocida was not phagocytosed by PMNs. AMs did not kill P. multocida, and similar intra- and extracellular reductions of P. multocida isolates by enrofloxacin were found. Intraphagocytic killing of A. pleuropneumoniae was significantly enhanced by enrofloxacin at 5× the MIC in both PMNs and AMs. AMs are very susceptible to the A. pleuropneumoniae cytotoxin. This suggests that in serologically naive pigs the enhancing effect of enrofloxacin on the bactericidal action of PMNs may have clinical relevance. PMID:10471554

Assessing the In Vitro Effectiveness of Antimicrobials against Mycoplasma mycoides subsp. mycoides Small-Colony Type To Reduce Contagious Bovine Pleuropneumonia Infection

PubMed Central

Ayling, R. D.; Bisgaard-Frantzen, S.; March, J. B.; Godinho, K.; Nicholas, R. A. J.

2005-01-01

In vitro minimum inhibitory concentrations were determined for 21 antimicrobials against 41 isolates of Mycoplasma mycoides subsp. mycoides small-colony type, the cause of contagious bovine pleuropneumonia. Of the antimicrobials used most widely in Africa, oxytetracycline and tilmicosin were effective, while the isolates were resistant to tylosin. These results provide a baseline for monitoring antimicrobial resistance. PMID:16304194

Genome Sequence of Actinobacillus seminis Strain ATCC 15768, a Reference Strain of Ovine Pathogens That Causes Infections in Reproductive Organs

PubMed Central

Negrete-Abascal, Erasmo; Montes-Garcia, Fernando; Vaca-Pacheco, Sergio; Leyto-Gil, Abraham M.; Fragoso-Garcia, Edgar; Carvente-Garcia, Roberto; Perez-Agueros, Sandra; Castelan-Sanchez, Hugo G.; Garcia-Molina, Alejandra; Villamar, Tomas E.; Sánchez-Alonso, Patricia

2018-01-01

ABSTRACT The draft genome sequence of Actinobacillus seminis strain ATCC 15768 is reported here. The genome comprises 22 contigs corresponding to 2.36 Mb with 40.7% G+C content and contains several genes related to virulence, including a putative RTX protein. PMID:29326222

Species-specific multiplex PCR for the diagnosis of Brucella ovis, Actinobacillus seminis, and Histophilus somni infection in rams.

PubMed

Moustacas, Valéria S; Silva, Teane M A; Costa, Luciana F; Xavier, Mariana N; Carvalho, Custódio A; Costa, Érica A; Paixão, Tatiane A; Santos, Renato L

2013-03-21

Infectious ovine epididymitis results in substantial economic losses worldwide due to reproductive failure and culling of breeders. The most common causative agents of these infections are Brucella ovis, Actinobacillus seminis, and Histophilus somni. The aim of this study was to develop a multiplex PCR assay for simultaneous detection of Brucella ovis, Actinobacillus seminis, and Histophilus somni with species-specific primers applied to biological samples for molecular diagnosis of these infections. The multiplex assay was capable of detecting B. ovis, A. seminis, and H. somni DNA simultaneously from genomic bacterial DNA samples and pool of semen samples from experimentally infected rams. The method was highly specific since it did not amplify DNA from other bacterial species that can potentially cause epididymitis in rams as well as species phylogenetically related to B. ovis. All negative control samples were negative in PCR multiplex assay. Urine can be used as an alternative to semen samples. The species-specific multiplex PCR assay developed in this study can be successfully used for the detection of three of the most common bacterial causes of ovine epididymitis.

Succinic acid production from cellobiose by Actinobacillus succinogenes.

PubMed

Jiang, Min; Xu, Rong; Xi, Yong-Lan; Zhang, Jiu-Hua; Dai, Wen-Yu; Wan, Yue-Jia; Chen, Ke-Quan; Wei, Ping

2013-05-01

In this study, cellobiose, a reducing disaccharide was used to produce succinic acid by Actinobacillus succinogenes NJ113. A final succinic acid concentration of 30.3g/l with a yield of 67.8% was achieved from an initial cellobiose concentration of 50 g/l via batch fermentation in anaerobic bottles. The cellobiose uptake mechanism was investigated and the results of enzyme assays revealed that the phosphoenolpyruvate phosphotransferase system (PEP-PTS) played an important role in the cellobiose uptake process. In batch fermentation with 18 g/l of cellobiose and 17 g/l of other sugars from sugarcane bagasse cellulose hydrolysates, a succinic acid concentration of 20.0 g/l was obtained, with a corresponding yield of 64.7%. This study found that cellobiose from incomplete hydrolysis of cellulose could be a potential carbon source for economical and efficient succinic acid production by A. succinogenes. Copyright © 2012 Elsevier Ltd. All rights reserved.

Intra-oral colonization of macaque monkeys by Actinobacillus actinomycetemcomitans

PubMed Central

Beighton, David; Taichman, Norton S.; Simpson, David L.; Dirienzo, Joseph M.; Johnson, Newell W.

2012-01-01

Actinobacillus actinomycetemcomitans was acquired by captive Macaca fascicularis 3 to 6 months after birth, and all monkeys aged over 6 months harbored detectable levels. This microorganism was most frequently isolated from the gingival plaque of the incisor (and other) teeth compared with other oral sites. Strains were leukotoxic by bioassay and Western blot analysis. Antibodies in macaque serum contained neutralized the leukotoxin of a human A. actinomycetemcomitans strain. High titres of maternal neutralizing anti-leukotoxin antibodies were detected in neonates; the titre then fell rapidly so that by 6 months the antibody titer was zero. Antileukotoxin antibody production was detected after 6 months of age, rapidly reaching a high level within 2 years after birth. The presence of leukotoxic strains of A. actinomycetemcomitans in the gingival region did not appear to be correlated with an increase in susceptibility to periodontal disease. PMID:2628866

Metabolic Engineering of Actinobacillus succinogenes Provides Insights into Succinic Acid Biosynthesis

PubMed Central

Guarnieri, Michael T.; Chou, Yat-Chen; Salvachúa, Davinia; Mohagheghi, Ali; St. John, Peter C.; Peterson, Darren J.; Bomble, Yannick J.

2017-01-01

ABSTRACT Actinobacillus succinogenes, a Gram-negative facultative anaerobe, exhibits the native capacity to convert pentose and hexose sugars to succinic acid (SA) with high yield as a tricarboxylic acid (TCA) cycle intermediate. In addition, A. succinogenes is capnophilic, incorporating CO2 into SA, making this organism an ideal candidate host for conversion of lignocellulosic sugars and CO2 to an emerging commodity bioproduct sourced from renewable feedstocks. In this work, we report the development of facile metabolic engineering capabilities in A. succinogenes, enabling examination of SA flux determinants via knockout of the primary competing pathways—namely, acetate and formate production—and overexpression of the key enzymes in the reductive branch of the TCA cycle leading to SA. Batch fermentation experiments with the wild-type and engineered strains using pentose-rich sugar streams demonstrate that the overexpression of the SA biosynthetic machinery (in particular, the enzyme malate dehydrogenase) enhances flux to SA. Additionally, removal of competitive carbon pathways leads to higher-purity SA but also triggers the generation of by-products not previously described from this organism (e.g., lactic acid). The resultant engineered strains also lend insight into energetic and redox balance and elucidate mechanisms governing organic acid biosynthesis in this important natural SA-producing microbe. IMPORTANCE Succinic acid production from lignocellulosic residues is a potential route for enhancing the economic feasibility of modern biorefineries. Here, we employ facile genetic tools to systematically manipulate competing acid production pathways and overexpress the succinic acid-producing machinery in Actinobacillus succinogenes. Furthermore, the resulting strains are evaluated via fermentation on relevant pentose-rich sugar streams representative of those from corn stover. Overall, this work demonstrates genetic modifications that can lead to succinic

Production of haemolysins by strains of the Actinobacillus minor/"porcitonsillarum" complex.

PubMed

Arya, Gitanjali; Niven, Donald F

2010-03-24

Actinobacillus minor and "Actinobacillus porcitonsillarum" are distinguished by their haemolytic activities, the latter organism being haemolytic and the former, non-haemolytic. Analysis of a whole genome shotgun sequence, however, revealed that A. minor strain 202, like "A. porcitonsillarum", possesses a haemolysin-encoding apxII operon. The purpose of this study was therefore to investigate haemolysin production by this organism and also by three additional members of the A. minor/"porcitonsillarum" complex, strains 33PN and 7ATS and A. minor strain NM305(T). Primers based on sequences within the apxII genes of strain 202 allowed the amplification of appropriately sized fragments from DNA from strain 33PN suggesting that this organism also possesses an apxII operon. Analysis of a whole genome shotgun sequence failed to reveal any trace of an apxII operon in strain NM305(T) and attempts to amplify apxII genes from DNA from strain 7ATS also failed. Strains 202 and 33PN, and surprisingly, the type strain of A. minor and strain 7ATS, were all found to be haemolysin-positive as growth media from cultures of these organisms could promote the lysis of erythrocytes in suspension. The erythrocyte specificities of the haemolysins produced by strains 202 and 33PN indicated that the haemolytic activities exhibited by these organisms were due to ApxII. In keeping with the apparent lack of apxII genes in strains NM305(T) and 7ATS, the haemolysins produced by these organisms were not erythrocyte-specific and with both organisms, haemolytic activity appeared to be due to a combination of heat-stable and heat-labile components. The identities of these components, however, remain unknown. Copyright 2009 Elsevier B.V. All rights reserved.

Metabolic Engineering of Actinobacillus succinogenes Provides Insights into Succinic Acid Biosynthesis.

PubMed

Guarnieri, Michael T; Chou, Yat-Chen; Salvachúa, Davinia; Mohagheghi, Ali; St John, Peter C; Peterson, Darren J; Bomble, Yannick J; Beckham, Gregg T

2017-09-01

Actinobacillus succinogenes , a Gram-negative facultative anaerobe, exhibits the native capacity to convert pentose and hexose sugars to succinic acid (SA) with high yield as a tricarboxylic acid (TCA) cycle intermediate. In addition, A. succinogenes is capnophilic, incorporating CO 2 into SA, making this organism an ideal candidate host for conversion of lignocellulosic sugars and CO 2 to an emerging commodity bioproduct sourced from renewable feedstocks. In this work, we report the development of facile metabolic engineering capabilities in A. succinogenes , enabling examination of SA flux determinants via knockout of the primary competing pathways-namely, acetate and formate production-and overexpression of the key enzymes in the reductive branch of the TCA cycle leading to SA. Batch fermentation experiments with the wild-type and engineered strains using pentose-rich sugar streams demonstrate that the overexpression of the SA biosynthetic machinery (in particular, the enzyme malate dehydrogenase) enhances flux to SA. Additionally, removal of competitive carbon pathways leads to higher-purity SA but also triggers the generation of by-products not previously described from this organism (e.g., lactic acid). The resultant engineered strains also lend insight into energetic and redox balance and elucidate mechanisms governing organic acid biosynthesis in this important natural SA-producing microbe. IMPORTANCE Succinic acid production from lignocellulosic residues is a potential route for enhancing the economic feasibility of modern biorefineries. Here, we employ facile genetic tools to systematically manipulate competing acid production pathways and overexpress the succinic acid-producing machinery in Actinobacillus succinogenes Furthermore, the resulting strains are evaluated via fermentation on relevant pentose-rich sugar streams representative of those from corn stover. Overall, this work demonstrates genetic modifications that can lead to succinic acid

Metabolic Engineering of Actinobacillus succinogenes Provides Insights into Succinic Acid Biosynthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guarnieri, Michael T.; Chou, Yat -Chen; Salvachua, Davinia Rodriquez

Actinobacillus succinogenes, a Gram-negative facultative anaerobe, exhibits the native capacity to convert pentose and hexose sugars to succinic acid (SA) with high yield as a tricarboxylic acid (TCA) cycle intermediate. In addition, A. succinogenes is capnophilic, incorporating CO 2 into SA, making this organism an ideal candidate host for conversion of lignocellulosic sugars and CO 2 to an emerging commodity bioproduct sourced from renewable feedstocks. In this work, we report the development of facile metabolic engineering capabilities in A. succinogenes, enabling examination of SA flux determinants via knockout of the primary competing pathways—namely, acetate and formate production—and overexpression of themore » key enzymes in the reductive branch of the TCA cycle leading to SA. Batch fermentation experiments with the wild-type and engineered strains using pentose-rich sugar streams demonstrate that the overexpression of the SA biosynthetic machinery (in particular, the enzyme malate dehydrogenase) enhances flux to SA. Additionally, removal of competitive carbon pathways leads to higher-purity SA but also triggers the generation of by-products not previously described from this organism (e.g., lactic acid). The resultant engineered strains also lend insight into energetic and redox balance and elucidate mechanisms governing organic acid biosynthesis in this important natural SA-producing microbe. IMPORTANCE Succinic acid production from lignocellulosic residues is a potential route for enhancing the economic feasibility of modern biorefineries. Here, we employ facile genetic tools to systematically manipulate competing acid production pathways and overexpress the succinic acid-producing machinery in Actinobacillus succinogenes. Furthermore, the resulting strains are evaluated via fermentation on relevant pentose-rich sugar streams representative of those from corn stover. Altogether, this work demonstrates genetic modifications that can lead to succinic

Metabolic Engineering of Actinobacillus succinogenes Provides Insights into Succinic Acid Biosynthesis

DOE PAGES

Guarnieri, Michael T.; Chou, Yat -Chen; Salvachua, Davinia Rodriquez; ...

2017-06-16

Actinobacillus succinogenes, a Gram-negative facultative anaerobe, exhibits the native capacity to convert pentose and hexose sugars to succinic acid (SA) with high yield as a tricarboxylic acid (TCA) cycle intermediate. In addition, A. succinogenes is capnophilic, incorporating CO 2 into SA, making this organism an ideal candidate host for conversion of lignocellulosic sugars and CO 2 to an emerging commodity bioproduct sourced from renewable feedstocks. In this work, we report the development of facile metabolic engineering capabilities in A. succinogenes, enabling examination of SA flux determinants via knockout of the primary competing pathways—namely, acetate and formate production—and overexpression of themore » key enzymes in the reductive branch of the TCA cycle leading to SA. Batch fermentation experiments with the wild-type and engineered strains using pentose-rich sugar streams demonstrate that the overexpression of the SA biosynthetic machinery (in particular, the enzyme malate dehydrogenase) enhances flux to SA. Additionally, removal of competitive carbon pathways leads to higher-purity SA but also triggers the generation of by-products not previously described from this organism (e.g., lactic acid). The resultant engineered strains also lend insight into energetic and redox balance and elucidate mechanisms governing organic acid biosynthesis in this important natural SA-producing microbe. IMPORTANCE Succinic acid production from lignocellulosic residues is a potential route for enhancing the economic feasibility of modern biorefineries. Here, we employ facile genetic tools to systematically manipulate competing acid production pathways and overexpress the succinic acid-producing machinery in Actinobacillus succinogenes. Furthermore, the resulting strains are evaluated via fermentation on relevant pentose-rich sugar streams representative of those from corn stover. Altogether, this work demonstrates genetic modifications that can lead to succinic

Genome Sequence of Actinobacillus seminis Strain ATCC 15768, a Reference Strain of Ovine Pathogens That Causes Infections in Reproductive Organs.

PubMed

Negrete-Abascal, Erasmo; Montes-Garcia, Fernando; Vaca-Pacheco, Sergio; Leyto-Gil, Abraham M; Fragoso-Garcia, Edgar; Carvente-Garcia, Roberto; Perez-Agueros, Sandra; Castelan-Sanchez, Hugo G; Garcia-Molina, Alejandra; Villamar, Tomas E; Sánchez-Alonso, Patricia; Vazquez-Cruz, Candelario

2018-01-11

The draft genome sequence of Actinobacillus seminis strain ATCC 15768 is reported here. The genome comprises 22 contigs corresponding to 2.36 Mb with 40.7% G+C content and contains several genes related to virulence, including a putative RTX protein. Copyright © 2018 Negrete-Abascal et al.

Whole Genome Sequence Analysis of Pig Respiratory Bacterial Pathogens with Elevated Minimum Inhibitory Concentrations for Macrolides.

PubMed

Dayao, Denise Ann Estarez; Seddon, Jennifer M; Gibson, Justine S; Blackall, Patrick J; Turni, Conny

2016-10-01

Macrolides are often used to treat and control bacterial pathogens causing respiratory disease in pigs. This study analyzed the whole genome sequences of one clinical isolate of Actinobacillus pleuropneumoniae, Haemophilus parasuis, Pasteurella multocida, and Bordetella bronchiseptica, all isolated from Australian pigs to identify the mechanism underlying the elevated minimum inhibitory concentrations (MICs) for erythromycin, tilmicosin, or tulathromycin. The H. parasuis assembled genome had a nucleotide transition at position 2059 (A to G) in the six copies of the 23S rRNA gene. This mutation has previously been associated with macrolide resistance but this is the first reported mechanism associated with elevated macrolide MICs in H. parasuis. There was no known macrolide resistance mechanism identified in the other three bacterial genomes. However, strA and sul2, aminoglycoside and sulfonamide resistance genes, respectively, were detected in one contiguous sequence (contig 1) of A. pleuropneumoniae assembled genome. This contig was identical to plasmids previously identified in Pasteurellaceae. This study has provided one possible explanation of elevated MICs to macrolides in H. parasuis. Further studies are necessary to clarify the mechanism causing the unexplained macrolide resistance in other Australian pig respiratory pathogens including the role of efflux systems, which were detected in all analyzed genomes.

[Cloning and sequence analysis of recombinant fusion gene of Escherichia coli heat-liable enterotoxin B subunit and Actinobacillus actinomycetemcomitans fimbria associative protein].

PubMed

Li, Yi; Sun, Hong-chen; Guo, Xue-jun; Feng, Shu-zhang

2005-02-01

To clone the recombinant fusion gene of Escherichia coli heat-liable enterotoxin B subunit (Ltb) and Actinobacillus actinomycetemcomitans fimbria associative protein (Fap). Two couples of primers were designed for PCR according to the known sequence of ltb and fap. The ltb and fap gene were obtained by amplification PCR technique from plasmid EWD299 of Escherichia coli and Actinobacillus actinomycetemcomitans 310 DNA respectively, and fused them by PCR. The fusion gene ltb-fap were cloning into plasmid pET28a(+). The recombined plasmid pET28a ltb-fap was transformed into Escherichia coli DH5alpha. The recombinant was screened and identified by restriction enzyme and PCR. The cloned gene was sequenced. The ltb-fap about 531bp in size was obtained successfully, and identified by PCR, restrictive enzyme and sequence analysis. The vector of pET28a ltb-fap was obtained.

Multifocal suppurative granuloma caused by Actinobacillus lignieresii in the peritoneum of a beef steer

PubMed Central

KASUYA, Kazufumi; MANCHANAYAKE, Tilusha; UENOYAMA, Kei; KAWA, Sayaka; TAKAYAMA, Kou; IMAI, Naoto; SHIBAHARA, Tomoyuki

2016-01-01

An imported crossbred Angus beef steer aged eight to twelve months died suddenly on the eighth day of a quarantine period in Japan. Gross examination showed the peritoneum and mesentery consisted of numerous nodules of various sizes. Histological examination revealed chronic suppurative granulomatous peritonitis with eosinophilic rosettes surrounding colonies of Gram-negative bacilli. The bacteria isolated from the nodules were confirmed to be Actinobacillus lignieresii based on the results of 16S rRNA gene sequencing and immunohistochemistry. Antibiotic sensitivity testing showed that the isolate was resistant to penicillin. Thus, a diagnosis of atypical actinobacillosis caused by A. lignieresii was made. PMID:27773882

Multifocal suppurative granuloma caused by Actinobacillus lignieresii in the peritoneum of a beef steer.

PubMed

Kasuya, Kazufumi; Manchanayake, Tilusha; Uenoyama, Kei; Kawa, Sayaka; Takayama, Kou; Imai, Naoto; Shibahara, Tomoyuki

2017-01-20

An imported crossbred Angus beef steer aged eight to twelve months died suddenly on the eighth day of a quarantine period in Japan. Gross examination showed the peritoneum and mesentery consisted of numerous nodules of various sizes. Histological examination revealed chronic suppurative granulomatous peritonitis with eosinophilic rosettes surrounding colonies of Gram-negative bacilli. The bacteria isolated from the nodules were confirmed to be Actinobacillus lignieresii based on the results of 16S rRNA gene sequencing and immunohistochemistry. Antibiotic sensitivity testing showed that the isolate was resistant to penicillin. Thus, a diagnosis of atypical actinobacillosis caused by A. lignieresii was made.

Qualitative and quantitative determination of enterobacterial common antigen (ECA) with monoclonal antibodies: expression of ECA by two Actinobacillus species.

PubMed Central

Böttger, E C; Jürs, M; Barrett, T; Wachsmuth, K; Metzger, S; Bitter-Suermann, D

1987-01-01

The presence and quantity of the enterobacterial common antigen (ECA) in several species belonging to the family Enterobacteriaceae as well as to other gram-negative families were determined by a solid-phase enzyme-linked immunosorbent assay system and Western blotting by using mouse monoclonal antibodies specific for ECA. Except for Erwinia chrysanthemi, previously known to be an exception, all species known or presumed to belong to Enterobacteriaceae produced ECA (89 of 90 species). Most species not belonging to Enterobacteriaceae did not produce ECA (25 of 28 species), with one already known (Plesiomonas shigelloides) and two hitherto unknown (Actinobacillus equuli and Actinobacillus suis) exceptions. Interestingly, all strains of P. shigelloides produced ECA, regardless of the presence of the Shigella sonnei cross-reacting O antigen. Quantitation of the amount of ECA in members of the family Enterobacteriaceae revealed a remarkable heterogeneity among genera and species as well as within one species. We conclude that the rapid, sensitive, and reliable determination of ECA is a useful aid in taxonomic classification and may help to characterize the relatedness of the family Enterobacteriaceae to other families. However, a quantitative analysis of ECA appears to be without value for these purposes. Images PMID:3818929

Use of 16S rRNA Sequencing for Identification of Actinobacillus ureae Isolated from a Cerebrospinal Fluid Sample

PubMed Central

Whitelaw, A. C.; Shankland, I. M.; Elisha, B. G.

2002-01-01

Actinobacillus ureae, previously Pasteurella ureae, has on rare occasions been described as a cause of human infection. Owing to its rarity, it may not be easily identified in clinical microbiology laboratories by standard tests. This report describes a patient with acute bacterial meningitis due to A. ureae. The identity of the isolate was determined by means of DNA sequence analysis of a portion of the 16S rRNA gene. PMID:11825992

Isolation of Actinobacillus seminis from a goat with clinical epididymo-orchitis in Brazil.

PubMed

dos Santos, Fabrine Alexandre; de Azevedo, Edísio Oliveira; de Azevedo, Sérgio Santos; Garino Júnior, Felício; Mota, Rinaldo Aparecido; de Cássia Peixoto Kim, Pomy; Gomes, Ana Lisa Vale; Alves, Clebert José

2014-01-01

The present study reports the first isolation of Actinobacillus seminis from a goat in Brazil. A four-year-old Moxotó breeding goat in a flock of 70 goats and 65 sheep reared together in the county of Patos, semiarid region of Northeastern Brazil, showed clinical signs of unilateral orchitis and epididymitis. Diagnosis of A. seminis infection was confirmed by association of clinical findings, bacterial isolation and 16S rRNA gene sequencing. This result suggests that A. seminis may be an additional cause of infertility in goats, and that sheep may be the source of infection because the mixed farming system allows the contact between sheep and goats in the semiarid region of Northeastern Brazil.

Isolation of Actinobacillus seminis from a goat with clinical epididymo-orchitis in Brazil

PubMed Central

dos Santos, Fabrine Alexandre; de Azevedo, Edísio Oliveira; de Azevedo, Sérgio Santos; Júnior, Felício Garino; Mota, Rinaldo Aparecido; de Cássia Peixoto Kim, Pomy; Gomes, Ana Lisa Vale; Alves, Clebert José

2014-01-01

The present study reports the first isolation of Actinobacillus seminis from a goat in Brazil. A four-year-old Moxotó breeding goat in a flock of 70 goats and 65 sheep reared together in the county of Patos, semiarid region of Northeastern Brazil, showed clinical signs of unilateral orchitis and epididymitis. Diagnosis of A. seminis infection was confirmed by association of clinical findings, bacterial isolation and 16S rRNA gene sequencing. This result suggests that A. seminis may be an additional cause of infertility in goats, and that sheep may be the source of infection because the mixed farming system allows the contact between sheep and goats in the semiarid region of Northeastern Brazil. PMID:24948932

Continuous succinic acid production from xylose by Actinobacillus succinogenes.

PubMed

Bradfield, Michael F A; Nicol, Willie

2016-02-01

Continuous, anaerobic fermentations of D-xylose were performed by Actinobacillus succinogenes 130Z in a custom, biofilm reactor at dilution rates of 0.05, 0.10 and 0.30 h(-1). Succinic acid yields on xylose (0.55-0.68 g g(-1)), titres (10.9-29.4 g L(-1)) and productivities (1.5-3.4 g L(-1) h(-1)) were lower than those of a previous study on glucose, but product ratios (succinic acid/acetic acid = 3.0-5.0 g g(-1)) and carbohydrate consumption rates were similar. Also, mass balance closures on xylose were up to 18.2 % lower than those on glucose. A modified HPLC method revealed pyruvic acid excretion at appreciable concentrations (1.2-1.9 g L(-1)) which improved the mass balance closure by up to 16.8 %. Furthermore, redox balances based on the accounted xylose consumed and the excreted metabolites, indicated an overproduction of reducing power. The oxidative pentose phosphate pathway was shown to be a plausible source of the additional reducing power.

Succinic acid production from sucrose by Actinobacillus succinogenes NJ113.

PubMed

Jiang, Min; Dai, Wenyu; Xi, Yonglan; Wu, Mingke; Kong, Xiangping; Ma, Jiangfeng; Zhang, Min; Chen, Kequan; Wei, Ping

2014-02-01

In this study, sucrose, a reproducible disaccharide extracted from plants, was used as the carbon source for the production of succinic acid by Actinobacillus succinogenes NJ113. During serum bottle fermentation, the succinic acid concentration reached 57.1g/L with a yield of 71.5%. Further analysis of the sucrose utilization pathways revealed that sucrose was transported and utilized via a sucrose phosphotransferase system, sucrose-6-phosphate hydrolase, and a fructose PTS. Compared to glucose utilization in single pathway, more pathways of A. succinogenes NJ113 are dependent on sucrose utilization. By changing the control strategy in a fed-batch culture to alleviate sucrose inhibition, 60.5g/L of succinic acid was accumulated with a yield of 82.9%, and the productivity increased by 35.2%, reaching 2.16g/L/h. Thus utilization of sucrose has considerable potential economics and environmental meaning. Copyright © 2014 Elsevier Ltd. All rights reserved.

Antimicrobial susceptibility monitoring of respiratory tract pathogens isolated from diseased cattle and pigs across Europe: the VetPath study.

PubMed

de Jong, Anno; Thomas, Valérie; Simjee, Shabbir; Moyaert, Hilde; El Garch, Farid; Maher, Kirsty; Morrissey, Ian; Butty, Pascal; Klein, Ulrich; Marion, Hervé; Rigaut, Delphine; Vallé, Michel

2014-08-06

VetPath is an ongoing pan-European antibiotic susceptibility monitoring programme collecting pathogens from diseased antimicrobial non-treated cattle, pigs and poultry. In the current study, 1001 isolates from cattle and pig respiratory tract infections were tested for their antimicrobial susceptibilities. Non-replicate lung samples or nasopharyngeal/nasal swabs were collected from animals with acute clinical signs in 11 countries during 2002-2006. Pasteurella multocida and Mannheimia haemolytica from cattle and P. multocida, Actinobacillus pleuropneumoniae and Streptococcus suis from pigs were isolated by standard methods. S. suis was also isolated from meningitis cases. MICs of 16 antibiotics were assessed centrally by broth microdilution following CLSI recommendations. Results were interpreted using CLSI breakpoints where available. P. multocida (231) and M. haemolytica (138) isolates were all susceptible to amoxicillin/clavulanic acid, ceftiofur, enrofloxacin and trimethoprim/sulfamethoxazole. Resistance to florfenicol and spectinomycin was 0.4% and 3.5% in P. multocida, respectively, and absent in M. haemolytica isolates. Tetracycline resistance was 5.7% and 14.6% for P. multocida and M. haemolytica. In pigs, 230 P. multocida, 220 A. pleuropneumoniae and 182 S. suis isolates were recovered. Resistance to amoxicillin/clavulanic acid, ceftiofur, enrofloxacin, florfenicol, tiamulin and tilmicosin was absent or <1%. Trimethoprim/sulfamethoxazole resistance was 3-6% and tetracycline resistance varied from 14.7% in A. pleuropneumoniae to 81.8% in S. suis. In conclusion, low resistance to antibiotics with defined clinical breakpoints, except for tetracycline, was observed among the major respiratory tract pathogens recovered from cattle and pigs. Since for approximately half of the antibiotics in this panel no CLSI-defined breakpoints were available, setting of the missing veterinary breakpoints is important. Copyright © 2014 Elsevier B.V. All rights reserved.

Minimum inhibitory concentrations of tulathromycin against respiratory bacterial pathogens isolated from clinical cases in European cattle and swine and variability arising from changes in in vitro methodology.

PubMed

Godinho, Kevin S; Keane, Sue G; Nanjiani, Ian A; Benchaoui, Hafid A; Sunderland, Simon J; Jones, M Anne; Weatherley, Andrew J; Gootz, Thomas D; Rowan, Tim G

2005-01-01

The in vitro activity of tulathromycin was evaluated against common bovine and porcine respiratory pathogens collected from outbreaks of clinical disease across eight European countries from 1998 to 2001. Minimum inhibitory concentrations (MICs) for one isolate of each bacterial species from each outbreak were determined using a broth microdilution technique. The lowest concentrations inhibiting the growth of 90% of isolates (MIC90) for tulathromycin were 2 microg/ml for Mannheimia (Pasteurella) haemolytica, 1 microg/ml for Pasteurella multocida (bovine), and 2 microg/ml for Pasteurella multocida (porcine) and ranged from 0.5 to 4 microg/ml for Histophilus somni (Haemophilus somnus) and from 4 to 16 microg/ml for Actinobacillus pleuropneumoniae. Isolates were retested in the presence of serum. The activity of tulathromycin against fastidious organisms was affected by culture conditions, and MICs were reduced in the presence of serum.

Haemophilus parasuis serovars isolated from pathological samples in Northern Italy.

PubMed

Luppi, A; Bonilauri, P; Dottori, M; Iodice, G; Gherpelli, Y; Merialdi, G; Maioli, G; Martelli, P

2013-04-01

From January 2007 to December 2011, a total of 106 Haemophilus parasuis strains isolated from pigs were serotyped by agar gel diffusion test (DG). Serovar 4 was the most prevalent (24.5%), followed by serovar 13 (19.8%) and serovar 5 (11.3%). Twenty-nine strains were non-typeable (27.3%). The strains were divided into two groups, depending on whether they were isolated from specific pathological lesions of systemic disease such as polyserositis, arthritis or meningitis (73 cases of 106) or from the lower respiratory tract of pigs suffering from bronchopneumonia (33 cases of 106). Serovars 4 and 13 had a higher prevalence in systemic infection (polyserositis) than in respiratory disease only. Pasteurella multocida (14/106), Streptococcus suis (7/106), Actinobacillus pleuropneumoniae (4/106), Bordetella bronchiseptica (3/106) and Arcanobacterium pyogenes (3/106) were isolated in association with H. parasuis. © 2012 Blackwell Verlag GmbH.

Phylogeny of 54 representative strains of species in the family Pasteurellaceae as determined by comparison of 16S rRNA sequences.

PubMed Central

Dewhirst, F E; Paster, B J; Olsen, I; Fraser, G J

1992-01-01

Virtually complete 16S rRNA sequences were determined for 54 representative strains of species in the family Pasteurellaceae. Of these strains, 15 were Pasteurella, 16 were Actinobacillus, and 23 were Haemophilus. A phylogenetic tree was constructed based on sequence similarity, using the Neighbor-Joining method. Fifty-three of the strains fell within four large clusters. The first cluster included the type strains of Haemophilus influenzae, H. aegyptius, H. aphrophilus, H. haemolyticus, H. paraphrophilus, H. segnis, and Actinobacillus actinomycetemcomitans. This cluster also contained A. actinomycetemcomitans FDC Y4, ATCC 29522, ATCC 29523, and ATCC 29524 and H. aphrophilus NCTC 7901. The second cluster included the type strains of A. seminis and Pasteurella aerogenes and H. somnus OVCG 43826. The third cluster was composed of the type strains of Pasteurella multocida, P. anatis, P. avium, P. canis, P. dagmatis, P. gallinarum, P. langaa, P. stomatis, P. volantium, H. haemoglobinophilus, H. parasuis, H. paracuniculus, H. paragallinarum, and A. capsulatus. This cluster also contained Pasteurella species A CCUG 18782, Pasteurella species B CCUG 19974, Haemophilus taxon C CAPM 5111, H. parasuis type 5 Nagasaki, P. volantium (H. parainfluenzae) NCTC 4101, and P. trehalosi NCTC 10624. The fourth cluster included the type strains of Actinobacillus lignieresii, A. equuli, A. pleuropneumoniae, A. suis, A. ureae, H. parahaemolyticus, H. parainfluenzae, H. paraphrohaemolyticus, H. ducreyi, and P. haemolytica. This cluster also contained Actinobacillus species strain CCUG 19799 (Bisgaard taxon 11), A. suis ATCC 15557, H. ducreyi ATCC 27722 and HD 35000, Haemophilus minor group strain 202, and H. parainfluenzae ATCC 29242. The type strain of P. pneumotropica branched alone to form a fifth group. The branching of the Pasteurellaceae family tree was quite complex. The four major clusters contained multiple subclusters. The clusters contained both rapidly and slowly evolving

A serosurvey for selected pathogens in Greek European wild boar

PubMed Central

Touloudi, A.; Valiakos, G.; Athanasiou, L. V.; Birtsas, P.; Giannakopoulos, A.; Papaspyropoulos, K.; Kalaitzis, C.; Sokos, C.; Tsokana, C. N.; Spyrou, V.; Petrovska, L.; Billinis, C.

2015-01-01

Objectives Serum samples, collected from 94 European wild boar (Sus scrofa) during the hunting seasons 2006 -2010 from different regions of Greece, were examined in order to estimate the role of these wildlife species as reservoir of pathogens important for livestock and/or public health. Materials and Methods The assays used for this purpose were commercial indirect ELISA for the detection of antibodies against porcine circovirus type 2 (PCV-2), porcine reproductive and respiratory syndrome (virus) (PRRSV), Aujeszky's disease virus (ADV), influenza A (IA) virus, Actinobacillus pleuropneumoniae, Mycoplasma hyopneumoniae, Salmonella species, Trichinella species and indirect immunofluorescence antibody test for the detection of antibodies against Toxoplasma gondii and Neospora caninum. Results Antibodies against PCV-2, PRRSV, ADV, IA virus,A. pleuropneumoniae, M. hyopneumoniae,Salmonella species, Trichinella species, T. gondii and N. caninum were detected in 19.1 per cent, 12.8 per cent, 35.1 per cent, 1.1 per cent, 57.4 per cent, 0 per cent, 4.3 per cent, 6.4 per cent, 5.2 per cent and 1.1 per cent of the samples, respectively. Cluster analysis revealed a hot spot of seropositivity near Bulgarian border; seropositivity to ADV was more common among female animals. Conclusions These results indicate exposure of wild boar to most of the above-mentioned pathogens, raising concern about the possibility that these species may pose a significant health risk for livestock and/or humans. PMID:26392908

[Optimization of succinic acid fermentation with Actinobacillus succinogenes by response surface methodology].

PubMed

Shen, Naikun; Qin, Yan; Wang, Qingyan; Xie, Nengzhong; Mi, Huizhi; Zhu, Qixia; Liao, Siming; Huang, Ribo

2013-10-01

Succinic acid is an important C4 platform chemical in the synthesis of many commodity and special chemicals. In the present work, different compounds were evaluated for succinic acid production by Actinobacillus succinogenes GXAS 137. Important parameters were screened by the single factor experiment and Plackeet-Burman design. Subsequently, the highest production of succinic acid was approached by the path of steepest ascent. Then, the optimum values of the parameters were obtained by Box-Behnken design. The results show that the important parameters were glucose, yeast extract and MgCO3 concentrations. The optimum condition was as follows (g/L): glucose 70.00, yeast extract 9.20 and MgCO3 58.10. Succinic acid yield reached 47.64 g/L at the optimal condition. Succinic acid increased by 29.14% than that before the optimization (36.89 g/L). Response surface methodology was proven to be a powerful tool to optimize succinic acid production.

Succinic acid production from acid hydrolysate of corn fiber by Actinobacillus succinogenes.

PubMed

Chen, Kequan; Jiang, Min; Wei, Ping; Yao, Jiaming; Wu, Hao

2010-01-01

Dilute acid hydrolysate of corn fiber was used as carbon source for the production of succinic acid by Actinobacillus succinogenes NJ113. The optimized hydrolysis conditions were obtained by orthogonal experiments. When corn fiber particles were of 20 mesh in size and treated with 1.0% sulfuric acid at 121 degrees C for 2 h, the total sugar yield could reach 63.3%. It was found that CaCO(3) neutralization combined with activated carbon adsorption was an effective method to remove fermentation inhibitors especially furfural that presented in the acid hydrolysate of corn fiber. Only 5.2% of the total sugar was lost, while 91.9% of furfural was removed. The yield of succinic acid was higher than 72.0% with the detoxified corn fiber hydrolysate as the carbon source in anaerobic bottles or 7.5 L fermentor cultures. It was proved that the corn fiber hydrolysate could be an alternative to glucose for the production of succinic acid by A. succinogenes NJ113.

Pyogranulomatous pleuropneumonia and mediastinitis in ferrets (Mustela putorius furo) associated with Pseudomonas luteola Infection.

PubMed

Martínez, J; Martorell, J; Abarca, M L; Olvera, A; Ramis, A; Woods, L; Cheville, N; Juan-Sallés, C; Moya, A; Riera, A; Soto, S

2012-01-01

Between 2008 and 2009, three pet ferrets from different sources presented with acute episode of dyspnoea. Cytological examination of pleural exudates revealed severe purulent inflammation with abundant clusters of rod-shaped microorganisms with a clear surrounding halo. Treatment was ineffective and the ferrets died 2-5 days later. Two ferrets were subjected to necropsy examination, which revealed pyothorax, mediastinal lymphadenopathy and multiple white nodules (1-2mm) in the lungs. Microscopical examination showed multifocal necrotizing-pyogranulomatous pleuropneumonia and lymphadenitis with aggregates of encapsulated microorganisms, some of which were positively stained by periodic acid-Schiff and alcian blue. In-situ hybridization for Pneumocystis spp., Ziehl-Neelsen staining and immunohistochemistry for distemper, coronavirus and influenza antigen were negative in all cases. Electron microscopically, the bacteria were 2-3 μm long with a thick electron-lucent capsule. Microbiology from one ferret yielded a pure culture of gram-negative bacteria identified phenotypically as Pseudomonas luteola. This speciation was later confirmed by 16S RNA gene amplification. Copyright © 2011. Published by Elsevier Ltd.

Optimization of succinic acid fermentation with Actinobacillus succinogenes by response surface methodology (RSM)*

PubMed Central

Zhang, Yun-jian; Li, Qiang; Zhang, Yu-xiu; Wang, Dan; Xing, Jian-min

2012-01-01

Succinic acid is considered as an important platform chemical. Succinic acid fermentation with Actinobacillus succinogenes strain BE-1 was optimized by central composite design (CCD) using a response surface methodology (RSM). The optimized production of succinic acid was predicted and the interactive effects between glucose, yeast extract, and magnesium carbonate were investigated. As a result, a model for predicting the concentration of succinic acid production was developed. The accuracy of the model was confirmed by the analysis of variance (ANOVA), and the validity was further proved by verification experiments showing that percentage errors between actual and predicted values varied from 3.02% to 6.38%. In addition, it was observed that the interactive effect between yeast extract and magnesium carbonate was statistically significant. In conclusion, RSM is an effective and useful method for optimizing the medium components and investigating the interactive effects, and can provide valuable information for succinic acid scale-up fermentation using A. succinogenes strain BE-1. PMID:22302423

CO2 Biofixation of Actinobacillus succinogenes Through Novel Amine-Functionalized Polystyrene Microsphere Materials.

PubMed

Zhu, Wenhao; Li, Qiang; Dai, Ning

2017-02-01

CO 2 -derived succinate production was enhanced by Actinobacillus succinogenes through polystyrene (PSt) microsphere materials for CO 2 adsorption in bioreactor, and the adhesion forces between A. succinogenes bacteria and PSt materials were characterized. Synthesized uniformly sized and highly cross-linked PSt microspheres had high specific surface areas. After modification with amine functional groups, the novel amine-functionalized PSt microspheres exhibited a high adsorption capacity of 25.3 mg CO 2 /g materials. After addition with the functionalized microspheres into the culture broth, CO 2 supply to the cells increased. Succinate production by A. succinogenes can be enhanced from 29.6 to 48.1 g L -1 . Moreover, the characterization of interaction forces between A. succinogenes cells and the microspheres indicated that the maximal adhesive force was about 250 pN. The amine-functionalized PSt microspheres can adsorb a large amount of CO 2 and be employed for A. succinogenes anaerobic cultivation in bioreactor for high-efficiency production of CO 2 -derived succinate.

Challenges of controlling contagious bovine pleuropneumonia in sub-Saharan Africa: a Zambian perspective.

PubMed

Muuka, Geoffrey; Songolo, Nadi; Kabilika, Swithine; Hang'ombe, Bernard M; Nalubamba, King S; Muma, John B

2013-01-01

Contagious bovine pleuropneumonia (CBPP) is a disease of economic importance that is widely distributed in sub-Saharan African and contributes significantly to cattle morbidity and mortality. Control of CBPP offers a number of challenges as a result many developing countries in Africa are still struggling with this disease. In this study, we look at the challenges encountered in CBPP control in sub-Saharan Africa from the Zambian perspective. In conducting this study, we reviewed scientific literature and reports from the Ministry of Agriculture and Livestock and related animal institutions, and also made interviews with experts and key government officials involved in CBPP control in Zambia. Among the challenges identified for the successful control of CBPP were as follows: failure in the delivery of veterinary services, lack of a cattle identification system, natural phenomenon, livestock husbandry systems in the traditional sector, human movements, traditional practices among cattle farmers and cattle marketing systems. It was seen that the epidemiology of CBPP in Zambia is influenced by both ecological and anthological factors. Therefore, design and implementation of any control or eradication programme should be area/regional-dependent taking into account the different factors influencing disease transmission and maintenance.

Evidence for apoptosis of murine macrophages by Actinobacillus actinomycetemcomitans infection.

PubMed

Kato, S; Muro, M; Akifusa, S; Hanada, N; Semba, I; Fujii, T; Kowashi, Y; Nishihara, T

1995-10-01

The gram-negative bacterium Actinobacillus actinomycetemcomitans is considered an important etiological agent in periodontal diseases. In this study, we show that A. actinomycetemcomitans strains are cytotoxic for the murine macrophage cell line J774.1. On the other hand, Porphyromonas gingivalis strains, other gram-negative oral species implicated in adult periodontitis, showed weak cytotoxic effects. For this to occur, A. actinomycetemcomitans had to gain entry into the macrophages, since cytotoxicity was prevented by cytochalasin D. We demonstrate that cell death induced by A. actinomycetemcomitans Y4 occurs through apoptosis, as shown by changes in nuclear morphology, an increase in the proportion of fragmented DNA, and the typical ladder pattern of DNA fragmentation indicative of apoptosis. We further sought to determine whether the cytotoxicity induced by A. actinomycetemcomitans Y4 could be modulated by the protein kinase inhibitors H7 and HA1004. Apoptotic cell death induced by A. actinomycetemcomitans Y4 was suppressed by H7 but was relatively unaffected by HA1004. These findings suggest that the signals of protein kinases may regulate apoptosis induced by A. actinomycetemcomitans Y4. The ability of A. actinomycetemcomitans to promote the apoptosis of macrophages may be important for the initiation of infection and the development of periodontal diseases.

Evidence for apoptosis of murine macrophages by Actinobacillus actinomycetemcomitans infection.

PubMed Central

Kato, S; Muro, M; Akifusa, S; Hanada, N; Semba, I; Fujii, T; Kowashi, Y; Nishihara, T

1995-01-01

The gram-negative bacterium Actinobacillus actinomycetemcomitans is considered an important etiological agent in periodontal diseases. In this study, we show that A. actinomycetemcomitans strains are cytotoxic for the murine macrophage cell line J774.1. On the other hand, Porphyromonas gingivalis strains, other gram-negative oral species implicated in adult periodontitis, showed weak cytotoxic effects. For this to occur, A. actinomycetemcomitans had to gain entry into the macrophages, since cytotoxicity was prevented by cytochalasin D. We demonstrate that cell death induced by A. actinomycetemcomitans Y4 occurs through apoptosis, as shown by changes in nuclear morphology, an increase in the proportion of fragmented DNA, and the typical ladder pattern of DNA fragmentation indicative of apoptosis. We further sought to determine whether the cytotoxicity induced by A. actinomycetemcomitans Y4 could be modulated by the protein kinase inhibitors H7 and HA1004. Apoptotic cell death induced by A. actinomycetemcomitans Y4 was suppressed by H7 but was relatively unaffected by HA1004. These findings suggest that the signals of protein kinases may regulate apoptosis induced by A. actinomycetemcomitans Y4. The ability of A. actinomycetemcomitans to promote the apoptosis of macrophages may be important for the initiation of infection and the development of periodontal diseases. PMID:7558299

Improving succinic acid production by Actinobacillus succinogenes from raw industrial carob pods.

PubMed

Carvalho, Margarida; Roca, Christophe; Reis, Maria A M

2016-10-01

Carob pods are an inexpensive by-product of locust bean gum industry that can be used as renewable feedstock for bio-based succinic acid. Here, for the first time, unprocessed raw carob pods were used to extract a highly enriched sugar solution, afterwards used as substrate to produce succinic acid using Actinobacillus succinogenes. Batch fermentations containing 30g/L sugars resulted in a production rate of 1.67gSA/L.h and a yield of 0.39gSA/g sugars. Taking advantage of A. succinogenes' metabolism, uncoupling cell growth from succinic acid production, a fed-batch mode was implemented to increase succinic acid yield and reduce by-products formation. This strategy resulted in a succinic acid yield of 0.94gSA/g sugars, the highest yield reported in the literature for fed-batch and continuous experiments, while maintaining by-products at residual values. Results demonstrate that raw carob pods are a highly efficient feedstock for bio-based succinic acid production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Succinic Acid Production from Cheese Whey using Actinobacillus succinogenes 130 Z

NASA Astrophysics Data System (ADS)

Wan, Caixia; Li, Yebo; Shahbazi, Abolghasem; Xiu, Shuangning

Actinobacillus succinogenes 130 Z was used to produce succinic acid from cheese whey in this study. At the presence of external CO2 supply, the effects of initial cheese whey concentration, pH, and inoculum size on the succinic acid production were studied. The by-product formation during the fermentation process was also analyzed. The highest succinic acid yield of 0.57 was obtained at initial cheese whey concentration of 50 g/L, while the highest succinic acid productivity of 0.58 g h-1 L-1 was obtained at initial cheese whey concentration of 100 g/L. Increase in pH and inoculum size caused higher succinic acid yield and productivity. At the preferred fermentation condition of pH 6.8, inoculum size of 5% and initial cheese whey concentration of 50 g/L, succinic acid yield of 0.57, and productivity of 0.44 g h-1 L-1 were obtained. Acetic acid and formic acid were the main by-products throughout the fermentation run of 48 h. It is feasible to produce succinic acid using lactose from cheese whey as carbon resource by A. succinogenes 130 Z.

Inhibition of Actinobacillus actinomycetemcomitans leukotoxicity by bacteria from the subgingival flora.

PubMed

Johansson, A; Hänström, L; Kalfas, S

2000-08-01

Actinobacillus actinomycetemcomitans produces a pore-forming leukotoxin that lyses human polymorphonuclear leukocytes and monocytes. Certain proteolytic bacteria may coexist with A. actinomycetemcomitans in periodontal pockets. We aimed therefore to examine whether oral bacteria can modify the leukotoxicity of A. actinomycetemcomitans. A total of 55 strains representing 45 bacterial species of the subgingival flora were tested. Each strain was incubated with the highly toxic strain of A. actinomycetemcomitans HK 1519 and the leukotoxic activity of the suspension against human polymorphonuclear leukocytes was determined from the activity of the lactate dehydrogenase released upon lysis of the leukocytes. Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Prevotella melaninogenica and Prevotella loeschii inhibited the leukotoxicity of A. actinomycetemcomitans cells as well as the activity of leukotoxin purified from the same strain. The bacterial strains without the ability to block leukotoxic activity also failed to destroy pure leukotoxin even after 5 h of incubation. The proteolytic degradation of leukotoxin by P. gingivalis was mainly dependent on the activity of the enzymes R- and K-gingipains. P. intermedia and P. nigrescens also degraded the leukotoxin by enzymes. The results imply a role of the periodontal microflora in modifying the virulence of A. actinomycetemcomitans by destroying its leukotoxin.

Effect of tilmicosin on chemotactic, phagocytic, and bactericidal activities of bovine and porcine alveolar macrophages.

PubMed

Brumbaugh, Gordon W; Herman, James D; Clancy, Julianne S; Burden, Kyland I; Barry, Tracie; Simpson, R B; López, Hector Sumano

2002-01-01

To evaluate chemotactic, phagocytic, and bactericidal activities of bovine and porcine alveolar macrophages (AM) exposed to tilmicosin. 12 healthy calves and 12 healthy pigs. Lungs were obtained immediately after euthanasia; AM were collected by means of bronchoalveolar lavage and density gradient centrifugation. Chemotactic activity was evaluated by exposing AM to lipopolysaccharide or macrophage inhibitory peptide during incubation with tilmicosin. Phagocytic activity was evaluated by incubating AM with tilmicosin for 24 hours and then with tilmicosin-resistant Salmonella serotype Typhimurium. Bactericidal activity was evaluated by incubating AM with tilmicosin (0, 10, or 20 microg/ml for bovine AM; 0 or 10 microg/ml or 10 microg/ml but washed free of tilmicosin for porcine AM) and then with Mannheimia haemolytica (bovine AM) or with Actinobacillus pleuropneumoniae or Pasteurella multocida (porcine AM). Tilmicosin had no significant effects on chemotactic or phagocytic activities of bovine or porcine AM. The time-course of bactericidal activity was best described by polynomial equations. Time to cessation of bacterial growth and area under the time versus bacterial number curve were significantly affected by incubation of AM with tilmicosin. Results show that bactericidal activity of bovine and porcine AM was enhanced by tilmicosin, but not in proportion to the reported ability of AM to concentrate tilmicosin intracellularly. With or without exposure to tilmicosin, the time-course of bactericidal activity of bovine AM against M haemolytica and of porcine AM against A pleuropneumoniae or P multocida was too complex to be reduced to a simple linear equation.

Development of a markerless knockout method for Actinobacillus succinogenes.

PubMed

Joshi, Rajasi V; Schindler, Bryan D; McPherson, Nikolas R; Tiwari, Kanupriya; Vieille, Claire

2014-05-01

Actinobacillus succinogenes is one of the best natural succinate-producing organisms, but it still needs engineering to further increase succinate yield and productivity. In this study, we developed a markerless knockout method for A. succinogenes using natural transformation or electroporation. The Escherichia coli isocitrate dehydrogenase gene with flanking flippase recognition target sites was used as the positive selection marker, making use of A. succinogenes's auxotrophy for glutamate to select for growth on isocitrate. The Saccharomyces cerevisiae flippase recombinase (Flp) was used to remove the selection marker, allowing its reuse. Finally, the plasmid expressing flp was cured using acridine orange. We demonstrate that at least two consecutive deletions can be introduced into the same strain using this approach, that no more than a total of 1 kb of DNA is needed on each side of the selection cassette to protect from exonuclease activity during transformation, and that no more than 200 bp of homologous DNA is needed on each side for efficient recombination. We also demonstrate that electroporation can be used as an alternative transformation method to obtain knockout mutants and that an enriched defined medium can be used for direct selection of knockout mutants on agar plates with high efficiency. Single-knockout mutants of the fumarate reductase and of the pyruvate formate lyase-encoding genes were obtained using this knockout strategy. Double-knockout mutants were also obtained by deleting the citrate lyase-, β-galactosidase-, and aconitase-encoding genes in the pyruvate formate lyase knockout mutant strain.

In vivo induced antigenic determinants of Actinobacillus actinomycetemcomitans.

PubMed

Cao, Sam Linsen; Progulske-Fox, Ann; Hillman, Jeffrey D; Handfield, Martin

2004-08-01

Actinobacillus actinomycetemcomitans is a Gram-negative capnophilic rod and the etiological agent of localized aggressive periodontitis. The genome-wide survey of A. actinomycetemcomitans using in vivo induced antigen technology (IVIAT) has previously resulted in the discovery of antigenic determinants expressed specifically in diseased patients. The present study evaluated the potential of these antigens as putative disease markers, and investigating their contribution to the pathogenesis of the microorganism. Sera from patients had a significantly greater antibody titer than sera from healthy controls against six antigens, which supports the in vivo expression of these antigens, and suggests their usefulness as disease markers. A. actinomycetemcomitans invasion of epithelium-derived HeLa cells resulted in the induction of all three genes tested, as evidenced by real-time PCR. Isogenic mutants of these three genes were constructed and the adhesion and intracellular survival of the mutants was assayed in a competition assay with the wild-type strain. A significant defect in the intracellular survival of two of these mutant strains (orf1402 and orf859) was found. This defect could not be attributed to an adhesion defect. In contrast, a mutation in vapA, a homologue of a novel putative transcriptional regulator, out-competed the wild-type strain in the same assay. The virulent phenotype was restored for a mutant strain in orf859 upon complementation. This data provided new insight into the pathogenic personality of A. actinomycetemcomitans in vivo and supported the use of HeLa cells as a valid in vitro host-pathogen interactions model for that microorganism. IVIAT is applicable to most pathogens and will undoubtedly lead to the discovery of novel therapies, antibiotics and diagnostic tools.

A genomic perspective on the potential of Actinobacillus succinogenes for industrial succinate production

PubMed Central

2010-01-01

Background Succinate is produced petrochemically from maleic anhydride to satisfy a small specialty chemical market. If succinate could be produced fermentatively at a price competitive with that of maleic anhydride, though, it could replace maleic anhydride as the precursor of many bulk chemicals, transforming a multi-billion dollar petrochemical market into one based on renewable resources. Actinobacillus succinogenes naturally converts sugars and CO2 into high concentrations of succinic acid as part of a mixed-acid fermentation. Efforts are ongoing to maximize carbon flux to succinate to achieve an industrial process. Results Described here is the 2.3 Mb A. succinogenes genome sequence with emphasis on A. succinogenes's potential for genetic engineering, its metabolic attributes and capabilities, and its lack of pathogenicity. The genome sequence contains 1,690 DNA uptake signal sequence repeats and a nearly complete set of natural competence proteins, suggesting that A. succinogenes is capable of natural transformation. A. succinogenes lacks a complete tricarboxylic acid cycle as well as a glyoxylate pathway, and it appears to be able to transport and degrade about twenty different carbohydrates. The genomes of A. succinogenes and its closest known relative, Mannheimia succiniciproducens, were compared for the presence of known Pasteurellaceae virulence factors. Both species appear to lack the virulence traits of toxin production, sialic acid and choline incorporation into lipopolysaccharide, and utilization of hemoglobin and transferrin as iron sources. Perspectives are also given on the conservation of A. succinogenes genomic features in other sequenced Pasteurellaceae. Conclusions Both A. succinogenes and M. succiniciproducens genome sequences lack many of the virulence genes used by their pathogenic Pasteurellaceae relatives. The lack of pathogenicity of these two succinogens is an exciting prospect, because comparisons with pathogenic Pasteurellaceae could

Opsonic antibody activity against Actinobacillus actinomycetemcomitans in patients with rapidly progressive periodontitis.

PubMed Central

Sjöström, K; Darveau, R; Page, R; Whitney, C; Engel, D

1992-01-01

Actinobacillus actinomycetemcomitans has been closely associated with early-onset, severe periodontitis, and such patients often have serum immunoglobulin G (IgG) antibodies reactive with antigens of this gram-negative pathogen. We examined the functionality and potential importance of these antibodies. The opsonic activity against A. actinomycetemcomitans of sera from 30 patients with rapidly progressive periodontitis (RPP) and from 28 periodontally normal subjects was tested by using polymorphonuclear leukocyte (PMN) chemiluminescence and bactericidal assays. Peak chemiluminescence values correlated strongly with killing observed in the PMN-dependent bactericidal assay (r = 0.88; P < 0.001). Neither the mean IgG titer nor the mean peak chemiluminescence differed significantly between the two groups. However, when the relationship between chemiluminescence and titer was examined, regression analysis showed that antibodies present in low-titer normal sera were significantly more effective at opsonizing A. actinomycetemcomitans than antibodies present in low-titer RPP patient sera (P = 0.04). Thus, periodontally normal individuals may be better able than RPP patients to clear A. actinomycetemcomitans in early stages of colonization, and anti-A. actinomycetemcomitans antibodies in RPP patients may be relatively ineffective in preventing infection by this organism. PMID:1398993

Succinic acid production by Actinobacillus succinogenes NJ113 using corn steep liquor powder as nitrogen source.

PubMed

Xi, Yong-lan; Chen, Ke-quan; Dai, Wen-yu; Ma, Jiang-feng; Zhang, Min; Jiang, Min; Wei, Ping; Ouyang, Ping-Kai

2013-05-01

In this study, corn steep liquor powder (CSL) was used as nitrogen source to replace the relatively costly yeast extract typically used for the production of succinic acid with Actinobacillus succinogenes NJ113. Moreover, when heme was added to the fermentation medium and the culture was agitated at a low speed, a maximum succinic acid concentration of 37.9 g/l was obtained from a glucose concentration of 50 g/l, and a productivity of 0.75 g/l/h was achieved. These yields are almost as high as for fermentation with glucose and yeast extract. These results suggest that heme-supplemented CSL may be a suitable alternative nitrogen source for a cost-effective method of producing succinic acid with A. succinogenes NJ113 while consuming less energy than previous methods. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development of a Markerless Knockout Method for Actinobacillus succinogenes

PubMed Central

Joshi, Rajasi V.; Schindler, Bryan D.; McPherson, Nikolas R.; Tiwari, Kanupriya

2014-01-01

Actinobacillus succinogenes is one of the best natural succinate-producing organisms, but it still needs engineering to further increase succinate yield and productivity. In this study, we developed a markerless knockout method for A. succinogenes using natural transformation or electroporation. The Escherichia coli isocitrate dehydrogenase gene with flanking flippase recognition target sites was used as the positive selection marker, making use of A. succinogenes's auxotrophy for glutamate to select for growth on isocitrate. The Saccharomyces cerevisiae flippase recombinase (Flp) was used to remove the selection marker, allowing its reuse. Finally, the plasmid expressing flp was cured using acridine orange. We demonstrate that at least two consecutive deletions can be introduced into the same strain using this approach, that no more than a total of 1 kb of DNA is needed on each side of the selection cassette to protect from exonuclease activity during transformation, and that no more than 200 bp of homologous DNA is needed on each side for efficient recombination. We also demonstrate that electroporation can be used as an alternative transformation method to obtain knockout mutants and that an enriched defined medium can be used for direct selection of knockout mutants on agar plates with high efficiency. Single-knockout mutants of the fumarate reductase and of the pyruvate formate lyase-encoding genes were obtained using this knockout strategy. Double-knockout mutants were also obtained by deleting the citrate lyase-, β-galactosidase-, and aconitase-encoding genes in the pyruvate formate lyase knockout mutant strain. PMID:24610845

Utilization of Electrically Reduced Neutral Red by Actinobacillus succinogenes: Physiological Function of Neutral Red in Membrane-Driven Fumarate Reduction and Energy Conservation

PubMed Central

Park, D. H.; Zeikus, J. G.

1999-01-01

Neutral red (NR) functioned as an electronophore or electron channel enabling either cells or membranes purified from Actinobacillus succinogenes to drive electron transfer and proton translocation by coupling fumarate reduction to succinate production. Electrically reduced NR, unlike methyl or benzyl viologen, bound to cell membranes, was not toxic, and chemically reduced NAD. The cell membrane of A. succinogenes contained high levels of benzyl viologen-linked hydrogenase (12.2 U), fumarate reductase (13.1 U), and diaphorase (109.7 U) activities. Fumarate reductase (24.5 U) displayed the highest activity with NR as the electron carrier, whereas hydrogenase (1.1 U) and diaphorase (0.8 U) did not. Proton translocation by whole cells was dependent on either electrically reduced NR or H2 as the electron donor and on the fumarate concentration. During the growth of Actinobacillus on glucose plus electrically reduced NR in an electrochemical bioreactor system versus on glucose alone, electrically reduced NR enhanced glucose consumption, growth, and succinate production by about 20% while it decreased acetate production by about 50%. The rate of fumarate reduction to succinate by purified membranes was twofold higher with electrically reduced NR than with hydrogen as the electron donor. The addition of 2-(n-heptyl)-4-hydroxyquinoline N-oxide to whole cells or purified membranes inhibited succinate production from H2 plus fumarate but not from electrically reduced NR plus fumarate. Thus, NR appears to replace the function of menaquinone in the fumarate reductase complex, and it enables A. succinogenes to utilize electricity as a significant source of metabolic reducing power. PMID:10198002

Occurrence of antimicrobial resistance among bacterial pathogens and indicator bacteria in pigs in different European countries from year 2002 – 2004: the ARBAO-II study

PubMed Central

Hendriksen, Rene S; Mevius, Dik J; Schroeter, Andreas; Teale, Christopher; Jouy, Eric; Butaye, Patrick; Franco, Alessia; Utinane, Andra; Amado, Alice; Moreno, Miguel; Greko, Christina; Stärk, Katharina DC; Berghold, Christian; Myllyniemi, Anna-Liisa; Hoszowski, Andrzej; Sunde, Marianne; Aarestrup, Frank M

2008-01-01

Background The project "Antibiotic resistance in bacteria of animal origin – II" (ARBAO-II) was funded by the European Union (FAIR5-QLK2-2002-01146) for the period 2003–05. The aim of this project was to establish a program for the continuous monitoring of antimicrobial susceptibility of pathogenic and indicator bacteria from food animals using validated and harmonised methodologies. In this report the first data on the occurrence of antimicrobial resistance among bacteria causing infections in pigs are reported. Methods Susceptibility data from 17,642 isolates of pathogens and indicator bacteria including Actinobacillus pleuropneumoniae, Streptococcus suis and Escherichia coli isolated from pigs were collected from fifteen European countries in 2002–2004. Results Data for A. pleuropneumoniae from infected pigs were submitted from five countries. Most of the isolates from Denmark were susceptible to all drugs tested with the exceptions of a low frequency of resistance to tetracycline and trimethoprim – sulphonamide. Data for S. suis were obtained from six countries. In general, a high level of resistance to tetracycline (48.0 – 92.0%) and erythromycin (29.1 – 75.0%) was observed in all countries whereas the level of resistance to ciprofloxacin and penicillin differed between the reporting countries. Isolates from England (and Wales), France and The Netherlands were all susceptible to penicillin. In contrast the proportion of strains resistant to ciprofloxacin ranged from 12.6 to 79.0% (2004) and to penicillin from 8.1 – 13.0% (2004) in Poland and Portugal. Data for E. coli from infected and healthy pigs were obtained from eleven countries. The data reveal a high level of resistance to tetracyclines, streptomycin and ampicillin among infected pigs whereas in healthy pigs the frequency of resistance was lower. Conclusion Bacterial resistance to some antimicrobials was frequent with different levels of resistance being observed to several antimicrobial

Carob pod water extracts as feedstock for succinic acid production by Actinobacillus succinogenes 130Z.

PubMed

Carvalho, Margarida; Roca, Christophe; Reis, Maria A M

2014-10-01

Carob pods are a by-product of locust bean gum industry containing more than 50% (w/w) sucrose, glucose and fructose. In this work, carob pod water extracts were used, for the first time, for succinic acid production by Actinobacillus succinogenes 130Z. Kinetic studies of glucose, fructose and sucrose consumption as individual carbon sources till 30g/L showed no inhibition on cell growth, sugar consumption and SA production rates. Sugar extraction from carob pods was optimized varying solid/liquid ratio and extraction time, maximizing sugar recovery while minimizing the extraction of polyphenols. Batch fermentations containing 10-15g/L total sugars resulted in a maximum specific SA production rate of 0.61Cmol/Cmol X.h, with a yield of 0.55Cmol SA/Cmol sugar and a volumetric productivity of 1.61g SA/L.h. Results demonstrate that carob pods can be a promising low cost feedstock for bio-based SA production. Copyright © 2014 Elsevier Ltd. All rights reserved.

Genomic Characterization of Haemophilus parasuis SH0165, a Highly Virulent Strain of Serovar 5 Prevalent in China

PubMed Central

Zhou, Rui; Jin, Qi; Fan, Yang; Bei, Weicheng; Chen, Huanchun

2011-01-01

Haemophilus parasuis can be either a commensal bacterium of the porcine respiratory tract or an opportunistic pathogen causing Glässer's disease, a severe systemic disease that has led to significant economical losses in the pig industry worldwide. We determined the complete genomic sequence of H. parasuis SH0165, a highly virulent strain of serovar 5, which was isolated from a hog pen in North China. The single circular chromosome was 2,269,156 base pairs in length and contained 2,031 protein-coding genes. Together with the full spectrum of genes detected by the analysis of metabolic pathways, we confirmed that H. parasuis generates ATP via both fermentation and respiration, and possesses an intact TCA cycle for anabolism. In addition to possessing the complete pathway essential for the biosynthesis of heme, this pathogen was also found to be well-equipped with different iron acquisition systems, such as the TonB system and ABC-type transport complexes, to overcome iron limitation during infection and persistence. We identified a number of genes encoding potential virulence factors, such as type IV fimbriae and surface polysaccharides. Analysis of the genome confirmed that H. parasuis is naturally competent, as genes related to DNA uptake are present. A nine-mer DNA uptake signal sequence (ACAAGCGGT), identical to that found in Actinobacillus pleuropneumoniae and Mannheimia haemolytica, followed by similar downstream motifs, was identified in the SH0165 genome. Genomic and phylogenetic comparisons with other Pasteurellaceae species further indicated that H. parasuis was closely related to another swine pathogenic bacteria A. pleuropneumoniae. The comprehensive genetic analysis presented here provides a foundation for future research on the metabolism, natural competence and virulence of H. parasuis. PMID:21611187

Succinic acid production from duckweed (Landoltia punctata) hydrolysate by batch fermentation of Actinobacillus succinogenes GXAS137.

PubMed

Shen, Naikun; Wang, Qingyan; Zhu, Jing; Qin, Yan; Liao, Siming; Li, Yi; Zhu, Qixia; Jin, Yanling; Du, Liqin; Huang, Ribo

2016-07-01

Duckweed is potentially an ideal succinic acid (SA) feedstock due to its high proportion of starch and low lignin content. Pretreatment methods, substrate content and nitrogen source were investigated to enhance the bioconversion of duckweed to SA and to reduce the costs of production. Results showed that acid hydrolysis was an effective pretreatment method because of its high SA yield. The optimum substrate concentration was 140g/L. The optimum substrate concentration was 140g/L. Corn steep liquor powder could be considered a feasible and inexpensive alternative to yeast extract as a nitrogen source. Approximately 57.85g/L of SA was produced when batch fermentation was conducted in a 1.3L stirred bioreactor. Therefore, inexpensive duckweed can be a promising feedstock for the economical and efficient production of SA through fermentation by Actinobacillus succinogenes GXAS137. Copyright © 2016. Published by Elsevier Ltd.

Immobilization of Actinobacillus succinogenes by adhesion or entrapment for the production of succinic acid.

PubMed

Corona-González, Rosa Isela; Miramontes-Murillo, Ricardo; Arriola-Guevara, Enrique; Guatemala-Morales, Guadalupe; Toriz, Guillermo; Pelayo-Ortiz, Carlos

2014-07-01

The production of succinic acid was studied with entrapped and adsorbed Actinobacillus succinogenes. The adsorption of fermentation products (organic acids in the concentration range of 1-20 g/L) on different supports was evaluated. It was found that succinic acid was adsorbed in small quantities on diatomite and zeolite (12.6 mg/g support). The highest production of succinic acid was achieved with A. succinogenes entrapped in agar beads. Batch fermentations with immobilized cells were carried out with glucose concentrations ranging from 20 to 80 g/L. Succinic acid (43.4 g/L) was obtained from 78.3g/L glucose, and a high productivity (2.83 g/Lh) was obtained with a glucose concentration of 37.6g/L. For repeated batch fermentations (5 cycles in 72 h) with immobilized cells in agar, the total glucose consumed was 147.55 g/L, while the production of succinic acid was 107 g/L. Immobilized cells reduced significantly the fermentation time, yield, productivity and final concentration of succinic acid. Copyright © 2014 Elsevier Ltd. All rights reserved.

Prediction of reaction knockouts to maximize succinate production by Actinobacillus succinogenes

PubMed Central

Nag, Ambarish; St. John, Peter C.; Crowley, Michael F.

2018-01-01

Succinate is a precursor of multiple commodity chemicals and bio-based succinate production is an active area of industrial bioengineering research. One of the most important microbial strains for bio-based production of succinate is the capnophilic gram-negative bacterium Actinobacillus succinogenes, which naturally produces succinate by a mixed-acid fermentative pathway. To engineer A. succinogenes to improve succinate yields during mixed acid fermentation, it is important to have a detailed understanding of the metabolic flux distribution in A. succinogenes when grown in suitable media. To this end, we have developed a detailed stoichiometric model of the A. succinogenes central metabolism that includes the biosynthetic pathways for the main components of biomass—namely glycogen, amino acids, DNA, RNA, lipids and UDP-N-Acetyl-α-D-glucosamine. We have validated our model by comparing model predictions generated via flux balance analysis with experimental results on mixed acid fermentation. Moreover, we have used the model to predict single and double reaction knockouts to maximize succinate production while maintaining growth viability. According to our model, succinate production can be maximized by knocking out either of the reactions catalyzed by the PTA (phosphate acetyltransferase) and ACK (acetyl kinase) enzymes, whereas the double knockouts of PEPCK (phosphoenolpyruvate carboxykinase) and PTA or PEPCK and ACK enzymes are the most effective in increasing succinate production. PMID:29381705

Prediction of reaction knockouts to maximize succinate production by Actinobacillus succinogenes.

PubMed

Nag, Ambarish; St John, Peter C; Crowley, Michael F; Bomble, Yannick J

2018-01-01

Succinate is a precursor of multiple commodity chemicals and bio-based succinate production is an active area of industrial bioengineering research. One of the most important microbial strains for bio-based production of succinate is the capnophilic gram-negative bacterium Actinobacillus succinogenes, which naturally produces succinate by a mixed-acid fermentative pathway. To engineer A. succinogenes to improve succinate yields during mixed acid fermentation, it is important to have a detailed understanding of the metabolic flux distribution in A. succinogenes when grown in suitable media. To this end, we have developed a detailed stoichiometric model of the A. succinogenes central metabolism that includes the biosynthetic pathways for the main components of biomass-namely glycogen, amino acids, DNA, RNA, lipids and UDP-N-Acetyl-α-D-glucosamine. We have validated our model by comparing model predictions generated via flux balance analysis with experimental results on mixed acid fermentation. Moreover, we have used the model to predict single and double reaction knockouts to maximize succinate production while maintaining growth viability. According to our model, succinate production can be maximized by knocking out either of the reactions catalyzed by the PTA (phosphate acetyltransferase) and ACK (acetyl kinase) enzymes, whereas the double knockouts of PEPCK (phosphoenolpyruvate carboxykinase) and PTA or PEPCK and ACK enzymes are the most effective in increasing succinate production.

Prediction of reaction knockouts to maximize succinate production by Actinobacillus succinogenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nag, Ambarish; St. John, Peter C.; Crowley, Michael F.

Succinate is a precursor of multiple commodity chemicals and bio-based succinate production is an active area of industrial bioengineering research. One of the most important microbial strains for bio-based production of succinate is the capnophilic gram-negative bacterium Actinobacillus succinogenes, which naturally produces succinate by a mixed-acid fermentative pathway. To engineer A. succinogenes to improve succinate yields during mixed acid fermentation, it is important to have a detailed understanding of the metabolic flux distribution in A. succinogenes when grown in suitable media. To this end, we have developed a detailed stoichiometric model of the A. succinogenes central metabolism that includes themore » biosynthetic pathways for the main components of biomass - namely glycogen, amino acids, DNA, RNA, lipids and UDP-N-Acetyl-a-D-glucosamine. We have validated our model by comparing model predictions generated via flux balance analysis with experimental results on mixed acid fermentation. Moreover, we have used the model to predict single and double reaction knockouts to maximize succinate production while maintaining growth viability. According to our model, succinate production can be maximized by knocking out either of the reactions catalyzed by the PTA (phosphate acetyltransferase) and ACK (acetyl kinase) enzymes, whereas the double knockouts of PEPCK (phosphoenolpyruvate carboxykinase) and PTA or PEPCK and ACK enzymes are the most effective in increasing succinate production.« less

Prediction of reaction knockouts to maximize succinate production by Actinobacillus succinogenes

DOE PAGES

Nag, Ambarish; St. John, Peter C.; Crowley, Michael F.; ...

2018-01-30

Succinate is a precursor of multiple commodity chemicals and bio-based succinate production is an active area of industrial bioengineering research. One of the most important microbial strains for bio-based production of succinate is the capnophilic gram-negative bacterium Actinobacillus succinogenes, which naturally produces succinate by a mixed-acid fermentative pathway. To engineer A. succinogenes to improve succinate yields during mixed acid fermentation, it is important to have a detailed understanding of the metabolic flux distribution in A. succinogenes when grown in suitable media. To this end, we have developed a detailed stoichiometric model of the A. succinogenes central metabolism that includes themore » biosynthetic pathways for the main components of biomass - namely glycogen, amino acids, DNA, RNA, lipids and UDP-N-Acetyl-a-D-glucosamine. We have validated our model by comparing model predictions generated via flux balance analysis with experimental results on mixed acid fermentation. Moreover, we have used the model to predict single and double reaction knockouts to maximize succinate production while maintaining growth viability. According to our model, succinate production can be maximized by knocking out either of the reactions catalyzed by the PTA (phosphate acetyltransferase) and ACK (acetyl kinase) enzymes, whereas the double knockouts of PEPCK (phosphoenolpyruvate carboxykinase) and PTA or PEPCK and ACK enzymes are the most effective in increasing succinate production.« less

[Effects of different neutralizing agents on succinate production by Actinobacillus succinogenes NJ113].

PubMed

Yang, Zhuona; Jiang, Min; Li, Jian; Fang, Xiaojiang; Ye, Guizi; Bai, Xuefei; Zheng, Xiaoyu; Wei, Ping

2010-11-01

Different neutralizing agents were used as pH controller to investigate their effects on the growth and succinic acid production of Actinobacillus succinogenes NJ113. The fermentation results showed that Ca(OH)2, CaCO3 and NH4OH were not suitable for succinic acid production by A. succinogenes NJ113 because of their negative effects on cell growth. When Na-base was used, cells would flocculate and lump, and due to the sodium ion concentration reaching to a high level, OD660 dropped sharply after 12 h of fermentation. Mg-base was better because there was no significant inhibition by magnesium ion. Two combined neutralizing agents were used to maintain pH level, one with NaOH and Mg(OH)2 while the other with Na2CO3 and Mg(OH)2. The optimum ratios of the combined neutralizing agents were both 1:1 (g:g) when using 100 g/L glucose. When NaOH and Mg(OH)2 were chosen with the ratio of 1:1(g:g), 69.8 g/L of the succinic acid and 74.5% of the yield was obtained.

First report on the molecular prevalence of Mycoplasma capricolum subspecies capripneumoniae (Mccp) in goats the cause of contagious caprine pleuropneumonia (CCPP) in Balochistan province of Pakistan.

PubMed

Awan, Mohammad Arif; Abbas, Ferhat; Yasinzai, Masoom; Nicholas, Robin A J; Babar, Shakeel; Ayling, Roger D; Attique, Mohammad Adnan; Ahmed, Zafar; Wadood, Abdul; Khan, Faisal Ameer

2010-10-01

Contagious caprine pleuropneumonia (CCPP) caused by Mycoplasma capricolum subspecies capripneumoniae (Mccp) is a disease of goats which causes high morbidity and mortality and is reported in many countries of the world. There are probably no reports on the molecular prevalence of Mccp, Mycoplasma capricolum subsp. capricolum (Mcc) and Mycoplasma putrefaciens (Mp) in Balochistan and any other part of Pakistan. Thirty goats (n = 30) with marked respiratory symptoms were selected and procured from forty goat flocks in Pishin district of Balochistan in 2008. The genomic deoxyribonucleic acid (DNA) from the lung samples (n = 30) of the slaughtered goats was purified and subjected to polymerase chain reaction (PCR) assays for the presence of Mycoplasma mycoides cluster members and Mp. The PCR-RFLP (restriction fragment length polymorphism) was also used to further confirm the Mccp. Of the thirty lung samples 17 (56.67%) were positive for the molecular prevalence of Mcc, Mccp and Mp. In total the molecular prevalence was observed as 17.65% for Mccp (n = 3), 70.59% for Mcc (n = 12) and 11.76% for Mp (n = 2). The RFLP profile has also validated the PCR results of Mccp by yielding two bands of 190 and 126 bp. The results of PCR-RFLP coupled with the presence of fibrinous pleuropneumonia and pleurisy during postmortem of goats (n = 3) strongly indicated the prevalence of CCPP in this part of world. Moreover the prevalence of Mcc and Mp is also alarming in the study area. We report for the very first time the molecular prevalence of Mcc, Mccp, and Mp in the lung tissues of goats in the Pishin district of Balochistan, Pakistan.

Sampling with poling-based flux balance analysis: optimal versus sub-optimal flux space analysis of Actinobacillus succinogenes.

PubMed

Binns, Michael; de Atauri, Pedro; Vlysidis, Anestis; Cascante, Marta; Theodoropoulos, Constantinos

2015-02-18

Flux balance analysis is traditionally implemented to identify the maximum theoretical flux for some specified reaction and a single distribution of flux values for all the reactions present which achieve this maximum value. However it is well known that the uncertainty in reaction networks due to branches, cycles and experimental errors results in a large number of combinations of internal reaction fluxes which can achieve the same optimal flux value. In this work, we have modified the applied linear objective of flux balance analysis to include a poling penalty function, which pushes each new set of reaction fluxes away from previous solutions generated. Repeated poling-based flux balance analysis generates a sample of different solutions (a characteristic set), which represents all the possible functionality of the reaction network. Compared to existing sampling methods, for the purpose of generating a relatively "small" characteristic set, our new method is shown to obtain a higher coverage than competing methods under most conditions. The influence of the linear objective function on the sampling (the linear bias) constrains optimisation results to a subspace of optimal solutions all producing the same maximal fluxes. Visualisation of reaction fluxes plotted against each other in 2 dimensions with and without the linear bias indicates the existence of correlations between fluxes. This method of sampling is applied to the organism Actinobacillus succinogenes for the production of succinic acid from glycerol. A new method of sampling for the generation of different flux distributions (sets of individual fluxes satisfying constraints on the steady-state mass balances of intermediates) has been developed using a relatively simple modification of flux balance analysis to include a poling penalty function inside the resulting optimisation objective function. This new methodology can achieve a high coverage of the possible flux space and can be used with and without

Actinobacillus actinomycetemcomitans in Human Periodontal Disease: a Cross-Sectional Microbiological Investigation

PubMed Central

Slots, Jørgen; Reynolds, Homer S.; Genco, Robert J.

1980-01-01

Actinobacillus actinomycetemcomitans is a facultative gram-negative bacterium which has been associated with severe oral and nonoral infections. This study examined its occurrence in the oral cavities of 10 normal juveniles, 11 normal adults, 10 juvenile periodontitis patients, and 12 adult periodontitis patients. Four deep periodontal pockets and two normal periodontal sites were sampled in the diseased patients, and six normal periodontal sites were sampled in the healthy individuals. In all subjects samples were obtained from the cheek, tongue, and saliva. Samples from a total of 172 normal periodontal sites, 83 deep periodontal pockets, 42 cheek mucosae, 42 tongue dorsa, and 42 salivas were examined. Isolation was performed by using a medium for selective isolation of A. actinomycetemcomitans (Trypticase soy agar [BBL Microbiology Systems] supplemented with 10% serum and 75 μg of bacitracin per ml). The carrier rates were 20% for normal juveniles, 36% for normal adults, 50% for adult periodontitis patients, and 90% for juvenile periodontitis patients. A. actinomycetemcomitans was on average recovered in about fivefold-higher numbers from infected deep periodontal pockets than from infected normal subgingival areas. Samples of periodontal pockets generally contained 100-fold-more cells of A. actinomycetemcomitans than did samples of the cheek, tongue, and saliva. A. actinomycetemcomitans is commonly isolated from patients with juvenile periodontitis, often isolated from patients with adult periodontitis, and occasionally isolated from normal juveniles and adults. Its primary oral ecological niche appears to be dental plaque and periodontal pockets. PMID:6968718

Respiratory glycerol metabolism of Actinobacillus succinogenes 130Z for succinate production.

PubMed

Schindler, Bryan D; Joshi, Rajasi V; Vieille, Claire

2014-09-01

Actinobacillus succinogenes 130Z naturally produces among the highest levels of succinate from a variety of inexpensive carbon substrates. A few studies have demonstrated that A. succinogenes can anaerobically metabolize glycerol, a waste product of biodiesel manufacture and an inexpensive feedstock, to produce high yields of succinate. However, all these studies were performed in the presence of yeast extract, which largely removes the redox constraints associated with fermenting glycerol, a highly reduced molecule. We demonstrated that A. succinogenes cannot ferment glycerol in minimal medium, but that it can metabolize glycerol by aerobic or anaerobic respiration. These results were expected based on the A. succinogenes genome, which encodes respiratory enzymes, but no pathway for 1,3-propanediol production. We investigated A. succinogenes's glycerol metabolism in minimal medium in a variety of respiratory conditions by comparing growth, metabolite production, and in vitro activity of terminal oxidoreductases. Nitrate inhibited succinate production by inhibiting fumarate reductase expression. In contrast, growth in the presence of dimethylsulfoxide and in microaerobic conditions allowed high succinate yields. The highest succinate yield was 0.75 mol/mol glycerol (75 % of the maximum theoretical yield) in continuous microaerobic cultures. A. succinogenes could also grow and produce succinate on partially refined glycerols obtained directly from biodiesel manufacture. Finally, by expressing a heterologous 1,3-propanediol synthesis pathway in A. succinogenes, we provide the first proof of concept that A. succinogenes can be engineered to grow fermentatively on glycerol.

Continuous succinic acid fermentation by Actinobacillus succinogenes in a packed-bed biofilm reactor.

PubMed

Ferone, Mariateresa; Raganati, Francesca; Ercole, Alessia; Olivieri, Giuseppe; Salatino, Piero; Marzocchella, Antonio

2018-01-01

Succinic acid is one of the most interesting platform chemicals that can be produced in a biorefinery approach. In this study, continuous succinic acid production by Actinobacillus succinogenes fermentation in a packed-bed biofilm reactor (PBBR) was investigated. The effects of the operating conditions tested, dilution rate (D), and medium composition (mixture of glucose, xylose, and arabinose-that simulate the composition of a lignocellulosic hydrolysate)-on the PBBR performances were investigated. The maximum succinic acid productivity of 35.0 g L -1  h -1 and the maximum SA concentration were achieved at a D  = 1.9 h -1 . The effect of HMF and furfural on succinic acid production was also investigated. HMF resulted to reduce succinic acid production by 22.6%, while furfural caused a reduction of 16% in SA production at the same dilution rate. Succinic acid production by A. succinogenes fermentation in a packed-bed reactor (PBBR) was successfully carried out for more than 5 months. The optimal results were obtained at the dilution rate 0.5 h -1 : 43.0 g L -1 of succinic acid were produced, glucose conversion was 88%; and the volumetric productivity was 22 g L -1  h -1 .

Succinic acid production from glycerol by Actinobacillus succinogenes using dimethylsulfoxide as electron acceptor.

PubMed

Carvalho, Margarida; Matos, Mariana; Roca, Christophe; Reis, Maria A M

2014-01-25

Glycerol, a highly abundant byproduct of the biodiesel industry, constitutes today a cheap feedstock for biobased succinic acid (SA) production. Actinobacillus succinogenes is one of the best SA producers. However, glycerol consumption by this biocatalyst is limited because of a redox imbalance during cell growth. The use of an external electron acceptor may improve the metabolism of SA synthesis by A. succinogenes in glycerol. In this study, the effect of dimethylsulfoxide (DMSO), an electron acceptor, on glycerol consumption and SA production by A. succinogenes under controlled fermentation conditions was investigated. Concentrations of DMSO between 1 and 4% (v/v) greatly promoted glycerol consumption and SA production by A. succinogenes. During fed-batch cultivation, SA concentration reached 49.62 g/L, with a product yield of 0.87 gSA/gGLR and a maximum production rate of 2.31 gSA/Lh, the highest values so far reported in the literature for A. succinogenes using glycerol as carbon source. These results show that using DMSO as external electron acceptor significantly promotes glycerol consumption and succinic acid production by A. succinogenes and may be used as a co-substrate, opening new perspectives for the use of glycerol by this biocatalyst. Copyright © 2013 Elsevier B.V. All rights reserved.

The pentose phosphate pathway leads to enhanced succinic acid flux in biofilms of wild-type Actinobacillus succinogenes.

PubMed

Bradfield, Michael F A; Nicol, Willie

2016-11-01

Increased pentose phosphate pathway flux, relative to total substrate uptake flux, is shown to enhance succinic acid (SA) yields under continuous, non-growth conditions of Actinobacillus succinogenes biofilms. Separate fermentations of glucose and xylose were conducted in a custom, continuous biofilm reactor at four different dilution rates. Glucose-6-phosphate dehydrogenase assays were performed on cell extracts derived from in situ removal of biofilm at each steady state. The results of the assays were coupled to a kinetic model that revealed an increase in oxidative pentose phosphate pathway (OPPP) flux relative to total substrate flux with increasing SA titre, for both substrates. Furthermore, applying metabolite concentration data to metabolic flux models that include the OPPP revealed similar flux relationships to those observed in the experimental kinetic analysis. A relative increase in OPPP flux produces additional reduction power that enables increased flux through the reductive branch of the TCA cycle, leading to increased SA yields, reduced by-product formation and complete closure of the overall redox balance.

Analysis of immune responses to recombinant proteins from strains of Mycoplasma mycoides subsp. mycoides, the causative agent of contagious bovine pleuropneumonia.

PubMed

Perez-Casal, Jose; Prysliak, Tracy; Maina, Teresa; Wang, Yejun; Townsend, Hugh; Berverov, Emil; Nkando, Isabel; Wesonga, Hezron; Liljander, Anne; Jores, Joerg; Naessens, Jan; Gerdts, Volker; Potter, Andrew

2015-11-15

Current contagious bovine pleuropneumonia (CBPP) vaccines are based on live-attenuated strains of Mycoplasma mycoides subsp. mycoides (Mmm). These vaccines have shortcomings in terms of efficacy, duration of immunity and in some cases show severe side effects at the inoculation site; hence the need to develop new vaccines to combat the disease. Reverse vaccinology approaches were used and identified 66 candidate Mycoplasma proteins using available Mmm genome data. These proteins were ranked by their ability to be recognized by serum from CBPP-positive cattle and thereafter used to inoculate naïve cattle. We report here the inoculation of cattle with recombinant proteins and the subsequent humoral and T-cell-mediated immune responses to these proteins and conclude that a subset of these proteins are candidate molecules for recombinant protein-based subunit vaccines for CBPP control. Copyright © 2015 Elsevier B.V. All rights reserved.

Coinfection by Ureaplasma spp., Photobacterium damselae and an Actinomyces-like microorganism in a bottlenose dolphin (Tursiops truncatus) with pleuropneumonia stranded along the Adriatic coast of Italy.

PubMed

Di Francesco, Gabriella; Cammà, Cesare; Curini, Valentina; Mazzariol, Sandro; Proietto, Umberto; Di Francesco, Cristina Esmeralda; Ferri, Nicola; Di Provvido, Andrea; Di Guardo, Giovanni

2016-04-01

A case of pleuropneumonia is reported in an adult male bottlenose dolphin (Tursiops truncatus) found stranded in 2014 along the Central Adriatic coast of Italy. A severe pyogranulomatous pneumonia and thoracic lymphadenopathy were present at necropsy. Numerous Splendore-Hoeppli bodies were found microscopically scattered throughout the lung. Histochemical evidence of Actinomyces-like organisms was obtained from the pulmonary parenchyma, with a strain of Photobacterium damselae subsp. piscicida and Ureaplasma spp. being also isolated from the same tissue. For the latter, a genome fragment of approximately 1400 bp from the 16s rDNA was amplified and sequenced. BLAST analysis revealed 100% identity with an uncultured Ureaplasma spp. (JQ193826.1). Copyright © 2016 Elsevier Ltd. All rights reserved.

An international collaborative study to determine the prevalence of contagious caprine pleuropneumonia by monoclonal antibody-based cELISA

PubMed Central

2014-01-01

Background Few serological tests are available for detecting antibodies against Mycoplasma capricolum subsp. capripneumoniae, the causal agent of contagious caprine pleuropneumonia (CCPP). The complement fixation test, the test prescribed for international trade purposes, uses a crude antigen that cross-reacts with all the other mycoplasma species of the “mycoides cluster” frequently infecting goat herds. The lack of a more specific test has been a real obstacle to the evaluation of the prevalence and economic impact of CCPP worldwide. A new competitive ELISA kit for CCPP, based on a previous blocking ELISA, was formatted at CIRAD and used to evaluate the prevalence of CCPP in some regions of Kenya, Ethiopia, Mauritius, Tajikistan and Pakistan in an international collaborative study. Results The strict specificity of the test was confirmed in CCPP-free goat herds exposed to other mycoplasma species of the “mycoides cluster”. Prevalence studies were performed across the enzootic range of the disease in Africa and Asia. Seroprevalence was estimated at 14.6% in the Afar region of Ethiopia, whereas all the herds presented for CCPP vaccination in Kenya tested positive (individual seroprevalence varied from 6 to 90% within each herd). In Mauritius, where CCPP emerged in 2009, nine of 62 herds tested positive. In Central Asia, where the disease was confirmed only recently, no positive animals were detected in the Wakhan District of Afghanistan or across the border in neighboring areas of Tajikistan, whereas seroprevalence varied between 2.7% and 44.2% in the other districts investigated and in northern Pakistan. The test was also used to monitor seroconversion in vaccinated animals. Conclusions This newly formatted CCPP cELISA kit has retained the high specificity of the original kit. It can therefore be used to evaluate the prevalence of CCPP in countries or regions without vaccination programs. It could also be used to monitor the efficacy of vaccination

Succinic acid-producing biofilms of Actinobacillus succinogenes: reproducibility, stability and productivity.

PubMed

Maharaj, K; Bradfield, M F A; Nicol, W

2014-09-01

Continuous anaerobic fermentations were performed in a biofilm reactor packed with Poraver® beads. Dilution rates (D) varied between 0.054 and 0.72 h(-1), and D-glucose and CO2 gas were used as carbon substrates. Steady-state conditions were shown to be repeatable and independent of the operational history. Production stability was achieved over periods exceeding 80 h at values of D below 0.32 h(-1). In these situations, steady-state variation (expressed as fluctuations in NaOH neutralisation flow rates) exhibited a standard deviation of less than 5 % while no indication of biofilm deactivation was detected. The total biomass amount was found to be independent of the dilution rate with an average dry concentration of 23.8 ± 2.9 g L(-1) obtained for all runs. This suggests that the attachment area controls the extent of biofilm accumulation. Specific succinic acid (SA) productivities, based on the total biomass amount, exhibited a substantial decrease with decreasing D. An SA volumetric productivity of 10.8 g L(-1) h(-1) was obtained at D = 0.7 h(-1)-the highest value reported to date in Actinobacillus succinogenes fermentations. SA yields on glucose increased with decreasing D, with a yield of 0.90 ± 0.01 g g(-1) obtained at a D of 0.054 h(-1). Production of formic acid approached zero with decreasing D, while the succinic to acetic acid ratio increased with decreasing D, resulting in an increasing SA yield on glucose.

Racial tropism of a highly toxic clone of Actinobacillus actinomycetemcomitans associated with juvenile periodontitis.

PubMed Central

Haubek, D; Dirienzo, J M; Tinoco, E M; Westergaard, J; López, N J; Chung, C P; Poulsen, K; Kilian, M

1997-01-01

Actinobacillus actinomycetemcomitans strains with enhanced levels of production of leukotoxin are characterized by a 530-bp deletion from the promoter region of the leukotoxin gene operon. Previous isolates with this deletion constituted a single clone belonging to serotype b, although they displayed minor differences among each other. We have analyzed the geographic dissemination of this clone by examining 326 A. actinomycetemcomitans isolates from healthy and periodontally diseased individuals as well as from patients with different types of extraoral infections originating from countries worldwide. A total of 38 isolates, all belonging to the same clone, showed the 530-bp deletion. Comparison of a 440-bp sequence from the promoter region of the leukotoxin gene operon from 10 of these strains revealed complete identity, which indicates that the deletion originates from a single mutational event. This particular clone was exclusively associated with localized juvenile periodontitis (LJP). In at least 12 of 28 families from which the clone was isolated, more than one family member had LJP. Notably, all the subjects carrying this clone had a genetic affiliation with the African population. These observations suggest that juvenile periodontitis in some adolescents with an African origin is associated with a disseminating clone of A. actinomycetemcomitans. PMID:9399490

Identification of an immunogenic protein of Actinobacillus seminis that is present in microvesicles

PubMed Central

2006-01-01

Abstract Actinobacillus seminis is a gram-negative bacterium of the Pasteurellaceae family that is involved in ovine epididymitis. Looking for a protein specific to this species, we determined the protein profile of subcellular fractions of A. seminis (American Type Culture Collection number 15768): proteins from the outer membrane (OMPs), inner membrane (IMPs), and cytoplasm (CPs). These profiles provide the first data, to our knowledge, regarding subcellular fractions of A. seminis. In the OMP fraction, we identified a protein with a molecular mass of 75 kDa that proved to be immunogenic and apparently specific for A. seminis. This conclusion was based on the reaction of hyperimmune serum of rabbits inoculated with whole cells of A. seminis that was tested against sonicated complete cells of reference strains and field isolates of Brucella ovis, Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni. No protein of these bacteria cross-reacted with the 75-kDa protein of A. seminis. Furthermore, when each type of hyperimmune serum was tested against the sonicated cells and each of the subcellular fractions of A. seminis, it did not recognize the A. seminis 75-kDa protein. We also isolated and identified this protein in microvesicles released to the culture supernatant. The results suggest that the 75-kDa protein could be used to establish a diagnostic test specific for ovine epididymitis caused by A. seminis. PMID:16548331

Contagious bovine pleuropneumonia vaccines and control strategies: recent data.

PubMed

Thiaucourt, F; Aboubakar, Y; Wesonga, H; Manso-Silvan, L; Blanchard, A

2004-01-01

Contagious bovine pleuropneumonia is one of the most threatening transboundary cattle disease in Africa. However, with the exception of Botswana, very few African countries were able to implement eradication strategies for this disease, after it had recently re-infected a number of countries. Previous experimental studies have shown that emergency vaccination campaigns, based on a single injection, were not inducing a sufficient protection level to prevent further spread of the disease. In addition, post-vaccinal reactions were sometimes reported in the field when using vaccine strain T1/44, leading cattle owners to refuse the vaccination. On the contrary, antibiotics are used quite often in the field but there are insufficient data to assess their efficacy properly. Therefore experimental studies were implemented: (i) to check if higher dosages of the vaccine would be able to induce higher protection rates and (ii) to elucidate the origin of the post-vaccinal reactions observed with T1/44 and (iii) to gain preliminary results on the efficacy of long-acting tetracycline. The first experiment included the use of three doses of vaccine strains T1/44 and T1sr: 10(7), 10(8) and 10(9) mycoplasmas per dose. T1/44 seemed to induce a higher protection (70%) than T1sr (60%). However, there was no observable dose effect for these vaccine strains. The second experiment was performed by injecting various MmmSC strains subcutaneously into susceptible cattle. One of these strains was an isolate obtained from a "Willems" reaction following a vaccination with T1/44. This isolate, called T1B, induced typical invading oedema at the injection site in a similar way to the pathogenic strain, whereas the original T1/44 vaccine strain did not. These findings indicate that the strain has reverted to virulence. Finally the antibiotic trials showed that long-acting tetracycline was able to reduce the losses due to the disease but could not prevent the persistence of viable MmmSC in treated

Actinobacillus equuli ssp. haemolyticus in a semi-occlusively treated horse bite wound in a 2-year-old girl.

PubMed

Schröttner, Percy; Schultz, Jurek; Rudolph, Wolfram; Gunzer, Florian; Thürmer, Alexander; Fitze, Guido; Jacobs, Enno

2013-01-01

We report on the isolation of Actinobacillus equuli ssp. haemolyticus from wound smears of a 2-year-old girl who was admitted to the hospital due to partial amputation of the distal phalanx of her right middle finger caused by a horse bite. A. equuli typically causes diseases in horses and only very few reports describing human infections (mostly associated with wounds) are available in the literature. Interestingly, although the bacteria could be found in consecutive samples taken at different points in time, there were no signs of advancing infection or inflammation. Moreover, the fingertip regenerated after 74 days under semi-occlusive dressings with very pleasant results. For strain identification two automated systems were employed producing discrepant results: VITEK 2 described the pathogens as Pasteurella pneumotropica while MALDI-TOF MS analysis revealed A. equuli. Sequence analysis of 16S rDNA gene finally confirmed A. equuli ssp. haemolyticus as the isolated strain. The antimicrobial susceptibility testing was performed according to the CLSI criteria for Pasteurella spp. Additionally we conducted a test according to the EUCAST criteria.

Reclassification of Actinobacillus muris as Muribacter muris gen. nov., comb. nov.

PubMed

Nicklas, Werner; Bisgaard, Magne; Aalbæk, Bent; Kuhnert, Peter; Christensen, Henrik

2015-10-01

To reinvestigate the taxonomy of [Actinobacillus] muris, 474 strains, mainly from mice and rats, were characterized by phenotype and 130 strains selected for genotypic characterization by 16S rRNA and partial rpoB gene sequencing. The type strain was further investigated by whole-genome sequencing. Phylogenetic analysis of the DNA sequences showed one monophyletic group with intragroup similarities of 96.7 and 97.2 % for the 16S rRNA and rpoB genes, respectively. The highest 16S rRNA gene sequence similarity to a taxon with a validly published name outside the group was 95.9 %, to the type strain of [Pasteurella] pneumotropica. The closest related taxon based on rpoB sequence comparison was 'Haemophilus influenzae-murium', with 88.4 % similarity. A new genus and a new combination, Muribacter muris gen. nov., comb. nov., are proposed based on a distinct phylogenetic position based on 16S rRNA and rpoB gene sequence comparisons, with major divergence from the existing genera of the family Pasteurellaceae. The new genus has the characteristics of [A.] muris with the emendation that acid formation from ( - )-d-mannitol and hydrolysis of aesculin are variable, while the α-glucosidase test is positive. There is no requirement for exogenously supplied NAD (V factor) for the majority of strains investigated; however, one strain was found to require NAD. The major fatty acids of the type strain of Muribacter muris were C14 : 0, C14 : 0 3-OH/iso-C16 : 1 I, C16 : 1ω7c and C16 : 0, which is in line with most genera of the Pasteurellaceae. The type strain of Muribacter muris is CCUG 16938T ( = NCTC 12432T = ATCC 49577T).

Use of corn steep liquor as an economical nitrogen source for biosuccinic acid production by Actinobacillus succinogenes

NASA Astrophysics Data System (ADS)

Tan, J. P.; Jahim, J. M.; Wu, T. Y.; Harun, S.; Mumtaz, T.

2016-06-01

Expensive raw materials are the driving force that leads to the shifting of the petroleum-based succinic acid production into bio-based succinic acid production by microorganisms. Cost of fermentation medium is among the main factors contributing to the total production cost of bio-succinic acid. After carbon source, nitrogen source is the second largest component of the fermentation medium, the cost of which has been overlooked for the past years. The current study aimed at replacing yeast extract- a costly nitrogen source with corn steep liquor for economical production of bio-succinic acid by Actinobacillus succinogenes 130Z. In this study, a final succinic acid concentration of 20.6 g/L was obtained from the use of corn steep liquor as the nitrogen source, which was comparable with the use of yeast extract as the nitrogen source that had a final succinate concentration of 21.4 g/l. In terms of economical wise, corn steep liquor was priced at 200 /ton, which was one fifth of the cost of yeast extract at 1000 /ton. Therefore, corn steep liquor can be considered as a potential nitrogen source in biochemical industries instead of the costly yeast extract.

Biosuccinic Acid from Lignocellulosic-Based Hexoses and Pentoses by Actinobacillus succinogenes: Characterization of the Conversion Process.

PubMed

Ferone, Mariateresa; Raganati, Francesca; Olivieri, Giuseppe; Salatino, Piero; Marzocchella, Antonio

2017-12-01

Succinic acid (SA) is a well-established chemical building block. Actinobacillus succinogenes fermentation is by far the most investigated route due to very promising high SA yield and titer on several sugars. This study contributes to include the SA production within the concept of biorefinery of lignocellulose biomass. The study was focused on the SA production by A. succinogenes DSM 22257 using sugars representative from lignocellulose hydrolysis-glucose, mannose, arabinose, and xylose-as carbon source. Single sugar batch fermentation tests and mixture sugar fermentation tests were carried out. All the sugars investigated were converted in succinic acid by A. succinogenes. The best fermentation performances were measured in tests with glucose as carbon source. The bacterial growth kinetics was characterized by glucose inhibition. No inhibition phenomena were observed with the other sugar investigated. The sugar mixture fermentation tests highlighted the synergic effects of the co-presence of the four sugars. Under the operating conditions tested, the final concentration of succinic acid in the sugar mixture test was larger (27 g/L) than that expected (25.5 g/L) by combining the fermentation of the single sugar. Moreover, the concentration of acetic and formic acid was lower, consequently obtaining an increment in the succinic acid specificity.

Succinic acid production by Actinobacillus succinogenes using hydrolysates of spent yeast cells and corn fiber.

PubMed

Chen, Ke-Quan; Li, Jian; Ma, Jiang-Feng; Jiang, Min; Wei, Ping; Liu, Zhong-Min; Ying, Han-Jie

2011-01-01

The enzymatic hydrolysate of spent yeast cells was evaluated as a nitrogen source for succinic acid production by Actinobacillus succinogenes NJ113, using corn fiber hydrolysate as a carbon source. When spent yeast cell hydrolysate was used directly as a nitrogen source, a maximum succinic acid concentration of 35.5 g/l was obtained from a glucose concentration of 50 g/l, with a glucose utilization of 95.2%. Supplementation with individual vitamins showed that biotin was the most likely factor to be limiting for succinic acid production with spent yeast cell hydrolysate. After supplementing spent yeast cell hydrolysate and 90 g/l of glucose with 150 μg/l of biotin, cell growth increased 32.5%, glucose utilization increased 37.6%, and succinic acid concentration was enhanced 49.0%. As a result, when biotin-supplemented spent yeast cell hydrolysate was used with corn fiber hydrolysate, a succinic acid yield of 67.7% was obtained from 70.3 g/l of total sugar concentration, with a productivity of 0.63 g/(l h). Our results suggest that biotin-supplemented spent yeast cell hydrolysate may be an alternative nitrogen source for the efficient production of succinic acid by A. succinogenes NJ113, using renewable resources. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

Fermentation and crystallization of succinic acid from Actinobacillus succinogenes ATCC55618 using fresh cassava root as the main substrate.

PubMed

Thuy, Nguyen Thi Huong; Kongkaew, Artit; Flood, Adrian; Boontawan, Apichat

2017-06-01

The fermentation of succinic acid from fresh cassava root using Actinobacillus succinogenes ATCC55618, and the recovery of the product using crystallization were investigated. Fresh cassava root is an ideal succinic acid feedstock due to its low price and high starch content. Saccharification was carried out using commercially available enzymes and diammonium phosphate was used as an inexpensive nitrogen source. Different fermentation modes were compared in terms of product yield and productivity. Results for fed-batch fermentations showed that a succinic acid titer of 151.44g/L, with yield and productivity of 1.51g SA /g glucose and 3.22g/L/h could be obtained. Seeded batch cooling crystallization was investigated after pre-treatment using nanofiltration. A succinic acid crystal purity of 99.35% with a relative crystallinity of 96.77% was obtained from high seeding experiments. These results indicated that fresh cassava roots could be an economically alternative feedstock for a high quality succinic acid production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ultrasonographic findings in goats with contagious caprine pleuropneumonia caused by Mycoplasma capricolum subsp. capripneumoniae.

PubMed

Tharwat, Mohamed; Al-Sobayil, Fahd

2017-08-22

In goats, contagious caprine pleuropneumonia (CCPP) is a cause of major economic losses in Africa, Asia and in the Middle East. There is no information emphasising the importance of diagnostic ultrasound in goats with CCPP caused by Mycoplasma capricolum subsp. capripneumoniae (Mccp). This study was designed to describe the ultrasonographic findings in goats with CCPP caused by Mccp and to correlate ultrasonographic with post-mortem findings. To this end, 55 goats with CCPP were examined. Twenty-five healthy adult goats were used as a control group. Major clinical findings included harried, painful respiration, dyspnoea and mouth breathing. On ultrasonography, a liver-like echotexture was imaged in 13 goats. Upon post-mortem examination, all 13 goats exhibited unilateral pulmonary consolidation. Seven goats had a unilateral hypoechoic pleural effusion. At necropsy, the related lung was consolidated and the pleural fluid appeared turbid and greenish. Pleural abscessiation detected in five goats was confirmed post-mortem. Twenty-eight goats had a bright, fibrinous matrix extending over the chest wall containing numerous anechoic fluid pockets with medial displacement and compression of lung tissue. Echogenic tags imaged floating in the fluid were found upon post-mortem examination to be fibrin. In two goats, a consolidated right parenchyma was imaged together with hypoechoic pericardial effusions with echogenic tags covering the epicardium. At necropsy, the right lung was consolidated in three goats and fibrin threads were found covering the epicardium and pericardium. In goats with CCPP, the extension and the severity of the pulmonary changes could not be verified with clinical certainty in most cases, whereas this was possible most of the time with sonography, thus making the prognosis easier. Ultrasonographic examination of the pleurae and the lungs helped in the detection of various lesions.

The respiratory immune system of pigs.

PubMed

Pabst, R

1996-11-01

Respiratory tract infections with bacteria like Actinobacillus pleuropneumoniae are extremely common in pigs and are of major veterinary relevance. The respiratory tract can be divided into the upper part, consisting of the nose, pharynx, larynx and trachea, and the lower part, consisting of the different parts of the lung. After bronchoscopy and bronchoalveolar lavage (BAL) had been established for pigs, interest grew in the unspecific parts of the immune system of the respiratory tract (such as macrophages, mast cells, the mucociliary function) and the specific immune system, consisting of the different lymphocyte subsets. In contrast to the rodent and human lung, the lung of the pig contains large numbers of intravascular macrophages with a high clearance capacity. The main focus of this paper is the localization, subset composition and quantification of lymphocytes in the pig lung: the intravascular and interstitial pool and the lymphocytes in the bronchial epithelium and lamina propria including bronchus-associated lymphoid tissue form the major compartments. In the BAL only a small proportion of nucleated cells are lymphocytes. The effects of age, antigen exposition, immunization and infection on the lymphocyte distribution in the pig lung are presented. In addition to veterinary aspects, the lung of pigs can also serve as a model for diseases in humans.

The Genome Sequence of Mannheimia haemolytica A1: Insights into Virulence, Natural Competence, and Pasteurellaceae Phylogeny†

PubMed Central

Gioia, Jason; Qin, Xiang; Jiang, Huaiyang; Clinkenbeard, Kenneth; Lo, Reggie; Liu, Yamei; Fox, George E.; Yerrapragada, Shailaja; McLeod, Michael P.; McNeill, Thomas Z.; Hemphill, Lisa; Sodergren, Erica; Wang, Qiaoyan; Muzny, Donna M.; Homsi, Farah J.; Weinstock, George M.; Highlander, Sarah K.

2006-01-01

The draft genome sequence of Mannheimia haemolytica A1, the causative agent of bovine respiratory disease complex (BRDC), is presented. Strain ATCC BAA-410, isolated from the lung of a calf with BRDC, was the DNA source. The annotated genome includes 2,839 coding sequences, 1,966 of which were assigned a function and 436 of which are unique to M. haemolytica. Through genome annotation many features of interest were identified, including bacteriophages and genes related to virulence, natural competence, and transcriptional regulation. In addition to previously described virulence factors, M. haemolytica encodes adhesins, including the filamentous hemagglutinin FhaB and two trimeric autotransporter adhesins. Two dual-function immunoglobulin-protease/adhesins are also present, as is a third immunoglobulin protease. Genes related to iron acquisition and drug resistance were identified and are likely important for survival in the host and virulence. Analysis of the genome indicates that M. haemolytica is naturally competent, as genes for natural competence and DNA uptake signal sequences (USS) are present. Comparison of competence loci and USS in other species in the family Pasteurellaceae indicates that M. haemolytica, Actinobacillus pleuropneumoniae, and Haemophilus ducreyi form a lineage distinct from other Pasteurellaceae. This observation was supported by a phylogenetic analysis using sequences of predicted housekeeping genes. PMID:17015664

GENETIC APPROACH TO THE STUDY OF EPIDEMIOLOGY AND PATHOGENESIS OF ACTINOBACILLUS ACTINOMYCETEMCOA4ITANS IN LOCALIZED JUVENILE PERIODONTITIS

PubMed Central

DiRienzo, J.M.; Slots, J.

2012-01-01

Summary Actinobacillus acrinomycetemcomirans isolates from periodontal pockets were examined for restriction fragment-length polymorphism using a characterized 4.7-kb DNA probe. A total of 6 patterns of RFLP was found in 133 isolates originating from 12 subjects. No relatedness was found between RFLP types and serotypes. Different periodontal sites within the same subject and different individuals within the same family sometimes showed only one type of A. actinomycetemcomitans RFLP. When members among the same family showed 2 RFLP types, children were always infected with the A. acfinomycefemcomitans strains found in at least one of the parents. These findings support the concept of familial spread of A. actinomycetemcomitans. A. actinomycetemcomitans RFLP type B, corresponding to reference strain JP2, seems to be particularly virulent, as indicated from the presence of RFLP type B in 3 subjects who converted from a healthy periodontal state to localized juvenile periodontitis. RFLP type B was not detected in any of the 21 A. acrinomycetemcomitans-infected patients with adult periodontitis. The RFLP method seems to be useful in determining the epidemiology and possibly the potential virulence of periodontal strains of A. actinomycetemcomitans. PMID:1982406

Succinic acid production by Actinobacillus succinogenes from batch fermentation of mixed sugars.

PubMed

Almqvist, Henrik; Pateraki, Chrysanthi; Alexandri, Maria; Koutinas, Apostolis; Lidén, Gunnar

2016-08-01

Succinic acid production from the monosaccharides xylose, arabinose, glucose, mannose and galactose was studied using the bacterium Actinobacillus succinogenes. In Duran bottle cultures, containing 10 g/L of each of sugar, succinic acid was produced from all sugars except for galactose. The highest succinate yield, 0.56 g/g, was obtained with glucose, whereas the succinate yield was 0.42, 0.38 and 0.44 g/g for xylose, mannose and arabinose, respectively. The specific succinate productivity was 0.7 g/g h for glucose, but below 0.2 g/g h for the other sugars. Batch bioreactor fermentations were carried out using a sugar mixture of the five sugars giving a total concentration of 50 g/L, mimicking the distribution of sugars in spent sulfite liquor (SSL) from Eucalyptus which is rich in xylose. In this mixture, an almost complete conversion of all sugars (except galactose) was achieved resulting in a final succinate concentration of 21.8-26.8 g/L and a total yield of 0.59-0.68 g/g. There was evidence of co-consumption of glucose and xylose, whereas mannose was consumed after glucose. The main by-products were acetate 0.14-0.20 g/g and formate 0.08-0.13 g/g. NADH balance calculations suggested that NADH required for succinate production was not met solely from formate and acetate production, but other means of NADH production was necessary. Results from mixed sugar fermentations were verified using SSL as substrate resulting in a succinate yield of 0.60 g/g. In addition, it was found that CO2 sparging could replace carbonate supply in the form of MgCO3 without affecting the succinate yield.

Nonspecific Adherence by Actinobacillus actinomycetemcomitans Requires Genes Widespread in Bacteria and Archaea

PubMed Central

Kachlany, Scott C.; Planet, Paul J.; Bhattacharjee, Mrinal K.; Kollia, Evyenia; DeSalle, Rob; Fine, Daniel H.; Figurski, David H.

2000-01-01

The gram-negative coccobacillus, Actinobacillus actinomycetemcomitans, is the putative agent for localized juvenile periodontitis, a particularly destructive form of periodontal disease in adolescents. This bacterium has also been isolated from a variety of other infections, notably endocarditis. Fresh clinical isolates of A. actinomycetemcomitans form tenacious biofilms, a property likely to be critical for colonization of teeth and other surfaces. Here we report the identification of a locus of seven genes required for nonspecific adherence of A. actinomycetemcomitans to surfaces. The recently developed transposon IS903φkan was used to isolate mutants of the rough clinical isolate CU1000 that are defective in tight adherence to surfaces (Tad−). Unlike wild-type cells, Tad− mutant cells adhere poorly to surfaces, fail to form large autoaggregates, and lack long, bundled fibrils. Nucleotide sequencing and genetic complementation analysis revealed a 6.7-kb region of the genome with seven adjacent genes (tadABCDEFG) required for tight adherence. The predicted TadA polypeptide is similar to VirB11, an ATPase involved in macromolecular transport. The predicted amino acid sequences of the other Tad polypeptides indicate membrane localization but no obvious functions. We suggest that the tad genes are involved in secretion of factors required for tight adherence of A. actinomycetemcomitans. Remarkably, complete and highly conserved tad gene clusters are present in the genomes of the bubonic plague bacillus Yersinia pestis and the human and animal pathogen Pasteurella multocida. Partial tad loci also occur in strikingly diverse Bacteria and Archaea. Our results show that the tad genes are required for tight adherence of A. actinomycetemcomitans to surfaces and are therefore likely to be essential for colonization and pathogenesis. The occurrence of similar genes in a wide array of microorganisms indicates that they have important functions. We propose that tad

Actinobacillus succinogenes ATCC 55618 Fermentation Medium Optimization for the Production of Succinic Acid by Response Surface Methodology

PubMed Central

Zhu, Li-Wen; Wang, Cheng-Cheng; Liu, Rui-Sang; Li, Hong-Mei; Wan, Duan-Ji; Tang, Ya-Jie

2012-01-01

As a potential intermediary feedstock, succinic acid takes an important place in bulk chemical productions. For the first time, a method combining Plackett-Burman design (PBD), steepest ascent method (SA), and Box-Behnken design (BBD) was developed to optimize Actinobacillus succinogenes ATCC 55618 fermentation medium. First, glucose, yeast extract, and MgCO3 were identified to be key medium components by PBD. Second, preliminary optimization was run by SA method to access the optimal region of the key medium components. Finally, the responses, that is, the production of succinic acid, were optimized simultaneously by using BBD, and the optimal concentration was located to be 84.6 g L−1 of glucose, 14.5 g L−1 of yeast extract, and 64.7 g L−1 of MgCO3. Verification experiment indicated that the maximal succinic acid production of 52.7 ± 0.8 g L−1 was obtained under the identified optimal conditions. The result agreed with the predicted value well. Compared with that of the basic medium, the production of succinic acid and yield of succinic acid against glucose were enhanced by 67.3% and 111.1%, respectively. The results obtained in this study may be useful for the industrial commercial production of succinic acid. PMID:23093852

Bagasse hydrolyzates from Agave tequilana as substrates for succinic acid production by Actinobacillus succinogenes in batch and repeated batch reactor.

PubMed

Corona-González, Rosa Isela; Varela-Almanza, Karla María; Arriola-Guevara, Enrique; Martínez-Gómez, Álvaro de Jesús; Pelayo-Ortiz, Carlos; Toriz, Guillermo

2016-04-01

The aim of this work was to obtain fermentable sugars by enzymatic or acid hydrolyses of Agave tequilana Weber bagasse in order to produce succinic acid with Actinobacillus succinogenes. Hydrolyses were carried out with mineral acids (sulfuric and hydrochloric acids) or a commercial cellulolytic enzyme, and were optimized statistically by a response surface methodology, having as factors the concentration of acid/enzyme and time of hydrolysis. The concentration of sugars obtained at optimal conditions for each hydrolysis were 21.7, 22.4y 19.8g/L for H2SO4, HCl and the enzymatic preparation respectively. Concerning succinic acid production, the enzymatic hydrolyzates resulted in the highest yield (0.446g/g) and productivity (0.57g/Lh) using A. succinogenes in a batch reactor system. Repeated batch fermentation with immobilized A. succinogenes in agar and with the enzymatic hydrolyzates resulted in a maximum concentration of succinic acid of 33.6g/L from 87.2g/L monosaccharides after 5 cycles in 40h, obtaining a productivity of 1.32g/Lh. Copyright © 2016. Published by Elsevier Ltd.

Simultaneous saccharification and fermentation of acid-pretreated rapeseed meal for succinic acid production using Actinobacillus succinogenes.

PubMed

Chen, Kequan; Zhang, Han; Miao, Yelian; Wei, Ping; Chen, Jieyu

2011-04-07

Rapeseed meal was evaluated for succinic acid production by simultaneous saccharification and fermentation using Actinobacillus succinogenes ATCC 55618. Diluted sulfuric acid pretreatment and subsequent hydrolysis with pectinase was used to release sugars from rapeseed meal. The effects of culture pH, pectinase loading and yeast extract concentration on succinic acid production were investigated. When simultaneous saccharification and fermentation of diluted acid pretreated rapeseed meal with a dry matter content of 12.5% (w/v) was performed at pH 6.4 and a pectinase loading of 2% (w/w, on dry matter) without supplementation of yeast extract, a succinic acid concentration of 15.5 g/L was obtained at a yield of 12.4 g/100g dry matter. Fed-batch simultaneous saccharification and fermentation was carried out with supplementation of concentrated pretreated rapeseed meal and pectinase at 18 and 28 h to yield a final dry matter content of 20.5% and pectinase loading of 2%, with the succinic acid concentration enhanced to 23.4 g/L at a yield of 11.5 g/100g dry matter and a productivity of 0.33 g/(Lh). This study suggests that rapeseed meal may be an alternative substrate for the efficient production of succinic acid by A. succinogenes without requiring nitrogen source supplementation. Copyright © 2011 Elsevier Inc. All rights reserved.

Structure of a bacterial toxin-activating acyltransferase.

PubMed

Greene, Nicholas P; Crow, Allister; Hughes, Colin; Koronakis, Vassilis

2015-06-09

Secreted pore-forming toxins of pathogenic Gram-negative bacteria such as Escherichia coli hemolysin (HlyA) insert into host-cell membranes to subvert signal transduction and induce apoptosis and cell lysis. Unusually, these toxins are synthesized in an inactive form that requires posttranslational activation in the bacterial cytosol. We have previously shown that the activation mechanism is an acylation event directed by a specialized acyl-transferase that uses acyl carrier protein (ACP) to covalently link fatty acids, via an amide bond, to specific internal lysine residues of the protoxin. We now reveal the 2.15-Å resolution X-ray structure of the 172-aa ApxC, a toxin-activating acyl-transferase (TAAT) from pathogenic Actinobacillus pleuropneumoniae. This determination shows that bacterial TAATs are a structurally homologous family that, despite indiscernible sequence similarity, form a distinct branch of the Gcn5-like N-acetyl transferase (GNAT) superfamily of enzymes that typically use acyl-CoA to modify diverse bacterial, archaeal, and eukaryotic substrates. A combination of structural analysis, small angle X-ray scattering, mutagenesis, and cross-linking defined the solution state of TAATs, with intermonomer interactions mediated by an N-terminal α-helix. Superposition of ApxC with substrate-bound GNATs, and assay of toxin activation and binding of acyl-ACP and protoxin peptide substrates by mutated ApxC variants, indicates the enzyme active site to be a deep surface groove.

High Sensitivity Crosslink Detection Coupled With Integrative Structure Modeling in the Mass Spec Studio *

PubMed Central

Sarpe, Vladimir; Rafiei, Atefeh; Hepburn, Morgan; Ostan, Nicholas; Schryvers, Anthony B.; Schriemer, David C.

2016-01-01

The Mass Spec Studio package was designed to support the extraction of hydrogen-deuterium exchange and covalent labeling data for a range of mass spectrometry (MS)-based workflows, to integrate with restraint-driven protein modeling activities. In this report, we present an extension of the underlying Studio framework and provide a plug-in for crosslink (XL) detection. To accommodate flexibility in XL methods and applications, while maintaining efficient data processing, the plug-in employs a peptide library reduction strategy via a presearch of the tandem-MS data. We demonstrate that prescoring linear unmodified peptide tags using a probabilistic approach substantially reduces search space by requiring both crosslinked peptides to generate sparse data attributable to their linear forms. The method demonstrates highly sensitive crosslink peptide identification with a low false positive rate. Integration with a Haddock plug-in provides a resource that can combine multiple sources of data for protein modeling activities. We generated a structural model of porcine transferrin bound to TbpB, a membrane-bound receptor essential for iron acquisition in Actinobacillus pleuropneumoniae. Using mutational data and crosslinking restraints, we confirm the mechanism by which TbpB recognizes the iron-loaded form of transferrin, and note the requirement for disparate sources of restraint data for accurate model construction. The software plugin is freely available at www.msstudio.ca. PMID:27412762

Variation in seropositivity for some respiratory disease agents in finishing pigs: epidemiological studies on some health parameters and farm and management conditions in the herds.

PubMed

Elbers, A R; Tielen, M J; Cromwijk, W A; Hunneman, W A

1992-01-01

The relationship between the extent of seropositivity for Aujeszky's disease virus (ADV), Actinobacillus pleuropneumoniae (App.) serotype 2 and porcine influenza (PI) viruses serotype H1N1 and H3N2 in pigs on the one hand and the health status of the pigs and some farm and management conditions in the herds on the other hand was studied in 45 pig finishing herds, all members of one integration group. The health status was assessed by the extent of clinical signs, the use of veterinary drugs and the prevalence of pathological lesions in pigs at slaughter. There was no relationship between the extent of seropositivity on the one hand and clinical signs and use of veterinary drugs on the other hand. However, there was a positive relationship between the extent of seropositivity and the percentage of pigs with lesions of the respiratory tract at slaughter. Furthermore, the study indicates that the variation in seropositivity between pigs herds is associated with management related factors that particularly influence the possibility of the spreading of viruses. A sero-epidemiological investigation in 14 pig herds with recurrent pneumonia problems revealed a high percentage of seropositive pigs per herd. Furthermore, in a large number of herds, pigs were simultaneously seropositive for ADV and App. serotype 2, for ADV and PI serotype H1N1 or for ADV and PI serotype H3N2.

High Sensitivity Crosslink Detection Coupled With Integrative Structure Modeling in the Mass Spec Studio.

PubMed

Sarpe, Vladimir; Rafiei, Atefeh; Hepburn, Morgan; Ostan, Nicholas; Schryvers, Anthony B; Schriemer, David C

2016-09-01

The Mass Spec Studio package was designed to support the extraction of hydrogen-deuterium exchange and covalent labeling data for a range of mass spectrometry (MS)-based workflows, to integrate with restraint-driven protein modeling activities. In this report, we present an extension of the underlying Studio framework and provide a plug-in for crosslink (XL) detection. To accommodate flexibility in XL methods and applications, while maintaining efficient data processing, the plug-in employs a peptide library reduction strategy via a presearch of the tandem-MS data. We demonstrate that prescoring linear unmodified peptide tags using a probabilistic approach substantially reduces search space by requiring both crosslinked peptides to generate sparse data attributable to their linear forms. The method demonstrates highly sensitive crosslink peptide identification with a low false positive rate. Integration with a Haddock plug-in provides a resource that can combine multiple sources of data for protein modeling activities. We generated a structural model of porcine transferrin bound to TbpB, a membrane-bound receptor essential for iron acquisition in Actinobacillus pleuropneumoniae Using mutational data and crosslinking restraints, we confirm the mechanism by which TbpB recognizes the iron-loaded form of transferrin, and note the requirement for disparate sources of restraint data for accurate model construction. The software plugin is freely available at www.msstudio.ca. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Poly-N-acetylglucosamine matrix polysaccharide impedes fluid convection and transport of the cationic surfactant cetylpyridinium chloride through bacterial biofilms.

PubMed

Ganeshnarayan, Krishnaraj; Shah, Suhagi M; Libera, Matthew R; Santostefano, Anthony; Kaplan, Jeffrey B

2009-03-01

Biofilms are composed of bacterial cells encased in a self-synthesized, extracellular polymeric matrix. Poly-beta(1,6)-N-acetyl-d-glucosamine (PNAG) is a major biofilm matrix component in phylogenetically diverse bacteria. In this study we investigated the physical and chemical properties of the PNAG matrix in biofilms produced in vitro by the gram-negative porcine respiratory pathogen Actinobacillus pleuropneumoniae and the gram-positive device-associated pathogen Staphylococcus epidermidis. The effect of PNAG on bulk fluid flow was determined by measuring the rate of fluid convection through biofilms cultured in centrifugal filter devices. The rate of fluid convection was significantly higher in biofilms cultured in the presence of the PNAG-degrading enzyme dispersin B than in biofilms cultured without the enzyme, indicating that PNAG decreases bulk fluid flow. PNAG also blocked transport of the quaternary ammonium compound cetylpyridinium chloride (CPC) through the biofilms. Binding of CPC to biofilms further impeded fluid convection and blocked transport of the azo dye Allura red. Bioactive CPC was efficiently eluted from biofilms by treatment with 1 M sodium chloride. Taken together, these findings suggest that CPC reacts directly with the PNAG matrix and alters its physical and chemical properties. Our results indicate that PNAG plays an important role in controlling the physiological state of biofilms and may contribute to additional biofilm-associated processes such as biocide resistance.

Utilization of CO2 fixating bacterium Actinobacillus succinogenes 130Z for simultaneous biogas upgrading and biosuccinic acid production.

PubMed

Gunnarsson, Ingólfur B; Alvarado-Morales, Merlin; Angelidaki, Irini

2014-10-21

Biogas is an attractive renewable energy carrier. However, it contains CO2 which limits its use for certain applications. Here we report a novel approach for removing CO2 from biogas and capturing it as a biochemical through a biological process. This approach entails converting CO2 into biosuccinic acid using the bacterial strain Actinobacillus succinogenes 130 Z, and simultaneously producing high-purity CH4 (> 95%). Results showed that when pressure during fermentation was increased from 101.325 to 140 kPa, higher CO2 solubility was achieved, thereby positively affecting final succinic acid yield and titer, CO2 consumption rate, and CH4 purity. When using biogas as the only CO2 source at 140 kPa, the CO2 consumption rate corresponded to 2.59 L CO2 L(-1) d(-1) with a final succinic acid titer of 14.4 g L(-1). Under this pressure condition, the highest succinic acid yield and biogas quality reached corresponded to 0.635 g g(-1) and 95.4% (v v(-1)) CH4 content, respectively, after 24 h fermentation. This work represents the first successful attempt to develop a system capable of upgrading biogas to vehicle fuel/gas grid quality and simultaneously produce biosuccinic acid, a valuable building block with large market potential in the near term.

Streptococcus equi subsp zooepidemicus pleuropneumonia and peritonitis in a dromedary camel (Camelus dromedarius) calf in North America.

PubMed

Stoughton, William B; Gold, Jenifer

2015-08-01

A 12-week-old female dromedary camel (Camelus dromedarius) calf was evaluated because of acute (< 24 hours) inappetence and lethargy. The calf was being bottle-fed because of maternal rejection. Physical examination revealed decreased bronchovesicular sounds and absent borborygmi. The rectal temperature was 38.9°C (102.0°F). A CBC indicated leukopenia with a degenerative left shift suggestive of a systemic infection. Results of abdominal and thoracic ultrasonography showed severe bicavitary effusion, peripheral lung consolidation, and intestinal hypomotility. Pleural and peritoneal fluid analysis confirmed a diagnosis of septic pleuritis and peritonitis. Results of aerobic bacterial culture of venous blood, peritoneal fluid, and pleural fluid samples indicated Streptococcus equi subsp zooepidemicus septicemia as the etiology for the polyserositis (ie, alpaca fever). Treatment with IV broad-spectrum antimicrobials, an NSAID, and pleural drainage was initiated. Clinical signs of pleuropneumonia, peritonitis, and systemic infection improved rapidly 24 hours after initiation of medical treatment. The calf was discharged from the hospital after 11 days, and antimicrobial treatment continued for 2 weeks after discharge. At follow-up approximately 4 weeks after hospital discharge (6 weeks after the initial examination), there were no clinical signs suggestive of relapse or any reported complications. S equi subsp zooepidemicus may cause polyserositis in Old World camelids (eg, dromedary camels) with signs similar to those seen in New World camelids (eg, alpaca and llama). The rapid response to medical treatment for the patient described suggested that S equi subsp zooepidemicus-induced polyserositis (alpaca fever) in dromedary camels may respond favorably to appropriate treatment. Reducing stress, reducing overcrowding, and separate housing of equids and camelids are suggested. Further studies are needed to better assess the epidemiology of alpaca fever in dromedary

Structural and Genetic Analyses of O Polysaccharide from Actinobacillus actinomycetemcomitans Serotype f

PubMed Central

Kaplan, Jeffrey B.; Perry, Malcolm B.; MacLean, Leann L.; Furgang, David; Wilson, Mark E.; Fine, Daniel H.

2001-01-01

The oral bacterium Actinobacillus actinomycetemcomitans is implicated as a causative agent of localized juvenile periodontitis (LJP). A. actinomycetemcomitans is classified into five serotypes (a to e) corresponding to five structurally and antigenically distinct O polysaccharide (O-PS) components of their respective lipopolysaccharide molecules. Serotype b has been reported to be the dominant serotype isolated from LJP patients. We determined the lipopolysaccharide O-PS structure from A. actinomycetemcomitans CU1000, a strain isolated from a 13-year-old African-American female with LJP which had previously been classified as serotype b. The O-PS of strain CU1000 consisted of a trisaccharide repeating unit composed of l-rhamnose and 2-acetamido-2-deoxy-d-galactose (molar ratio, 2:1) with the structure →2)-α-l-Rhap-(1–3)-2-O-(β-d-GalpNAc)-α-l-Rhap-(1→. O-PS from strain CU1000 was structurally and antigenically distinct from the O-PS molecules of the five known A. actinomycetemcomitans serotypes. Strain CU1000 was mutagenized with transposon IS903φkan, and three mutants that were deficient in O-PS synthesis were isolated. All three transposon insertions mapped to a single 1-kb region on the chromosome. The DNA sequence of a 13.1-kb region surrounding these transposon insertions contained a cluster of 14 open reading frames that was homologous to gene clusters responsible for the synthesis of A. actinomycetemcomitans serotype b, c, and e O-PS antigens. The CU1000 gene cluster contained two genes that were not present in serotype-specific O-PS antigen clusters of the other five known A. actinomycetemcomitans serotypes. These data indicate that strain CU1000 should be assigned to a new A. actinomycetemcomitans serotype, designated serotype f. A PCR assay using serotype-specific PCR primers showed that 3 out of 20 LJP patients surveyed (15%) harbored A. actinomycetemcomitans strains carrying the serotype f gene cluster. The finding of an A

Quantitative risk assessment of entry of contagious bovine pleuropneumonia through live cattle imported from northwestern Ethiopia.

PubMed

Woube, Yilkal Asfaw; Dibaba, Asseged Bogale; Tameru, Berhanu; Fite, Richard; Nganwa, David; Robnett, Vinaida; Demisse, Amsalu; Habtemariam, Tsegaye

2015-11-01

Contagious bovine pleuropneumonia (CBPP) is a highly contagious bacterial disease of cattle caused by Mycoplasma mycoides subspecies mycoides small colony (SC) bovine biotype (MmmSC). It has been eradicated from many countries; however, the disease persists in many parts of Africa and Asia. CBPP is one of the major trade-restricting diseases of cattle in Ethiopia. In this quantitative risk assessment the OIE concept of zoning was adopted to assess the entry of CBPP into an importing country when up to 280,000 live cattle are exported every year from the northwestern proposed disease free zone (DFZ) of Ethiopia. To estimate the level of risk, a six-tiered risk pathway (scenario tree) was developed, evidences collected and equations generated. The probability of occurrence of the hazard at each node was modelled as a probability distribution using Monte Carlo simulation (@RISK software) at 10,000 iterations to account for uncertainty and variability. The uncertainty and variability of data points surrounding the risk estimate were further quantified by sensitivity analysis. In this study a single animal destined for export from the northwestern DFZ of Ethiopia has a CBPP infection probability of 4.76×10(-6) (95% CI=7.25×10(-8) 1.92×10(-5)). The probability that at least one infected animal enters an importing country in one year is 0.53 (90% CI=0.042-0.97). The expected number of CBPP infected animals exported any given year is 1.28 (95% CI=0.021-5.42). According to the risk estimate, an average of 2.73×10(6) animals (90% CI=10,674-5.9×10(6)) must be exported to get the first infected case. By this account it would, on average, take 10.15 years (90% CI=0.24-23.18) for the first infected animal to be included in the consignment. Sensitivity analysis revealed that prevalence and vaccination had the highest impact on the uncertainty and variability of the overall risk. Copyright © 2015 Elsevier B.V. All rights reserved.

Risk factors associated with contagious caprine pleuro-pneumonia in goats in pastoral areas in the Rift Valley region of Kenya.

PubMed

Kipronoh, K A; Ombui, J N; Binepal, Y S; Wesonga, H O; Gitonga, E K; Thuranira, E; Kiara, H K

2016-09-15

A cross-sectional study to determine risk factors associated with sero-prevalence of contagious caprine pleuro-pneumonia (CCPP) in goats was carried out between the months of March, 2014 and March, 2015 in Pokot East, Turkana West and Kajiado Central Sub-counties. A semi-structured questionnaire focusing on risk factors for CCPP was completed for each flock whose serum samples were collected. A logistic regression model was developed to assess the association between the risk factors and CCPP sero-positivity. Of the 54 flocks, 49 (90.7%) presented at least one sero-positive animal. Two hundred and four of the 432 goats tested sero-positive at monoclonal antibody based competitive Enzyme-linked immuno-sorbent assay (c-ELISA), hence a sero-prevalence of 47.2% (95% CI=42.5- 51.9). Previous exposure of flocks to CCPP (p<0.001, OR=52.8; CI=6.45, 432), distant sources of veterinary drugs (p<0.001, OR=6.17; CI=3.41, 11.1), movement of goats to dry season feeding areas (p<0.001, OR=4.31; CI=2.39, 7.75) and markets as a source of new introductions to the flock (p=0.033, OR=1.86; CI=1.05, 3.27) were identified as risk factors significantly associated with CCPP sero-prevalence. The findings provide further evidence supporting the high prevalence and endemic state of the disease in pastoral flocks and hence there is need for adequate measures to be put in place to control the disease effectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Cu,Zn superoxide dismutase structure from a microbial pathogen establishes a class with a conserved dimer interface.

PubMed

Forest, K T; Langford, P R; Kroll, J S; Getzoff, E D

2000-02-11

Macrophages and neutrophils protect animals from microbial infection in part by issuing a burst of toxic superoxide radicals when challenged. To counteract this onslaught, many Gram-negative bacterial pathogens possess periplasmic Cu,Zn superoxide dismutases (SODs), which act on superoxide to yield molecular oxygen and hydrogen peroxide. We have solved the X-ray crystal structure of the Cu,Zn SOD from Actinobacillus pleuropneumoniae, a major porcine pathogen, by molecular replacement at 1.9 A resolution. The structure reveals that the dimeric bacterial enzymes form a structurally homologous class defined by a water-mediated dimer interface, and share with all Cu,Zn SODs the Greek-key beta-barrel subunit fold with copper and zinc ions located at the base of a deep loop-enclosed active-site channel. Our structure-based sequence alignment of the bacterial enzymes explains the monomeric nature of at least two of these, and suggests that there may be at least one additional structural class for the bacterial SODs. Two metal-mediated crystal contacts yielded our C222(1) crystals, and the geometry of these sites could be engineered into proteins recalcitrant to crystallization in their native form. This work highlights structural differences between eukaryotic and prokaryotic Cu,Zn SODs, as well as similarities and differences among prokaryotic SODs, and lays the groundwork for development of antimicrobial drugs that specifically target periplasmic Cu,Zn SODs of bacterial pathogens. Copyright 12000 Academic Press.

Applying definitions for multidrug resistance, extensive drug resistance and pandrug resistance to clinically significant livestock and companion animal bacterial pathogens.

PubMed

Sweeney, Michael T; Lubbers, Brian V; Schwarz, Stefan; Watts, Jeffrey L

2018-06-01

Standardized definitions for MDR are currently not available in veterinary medicine despite numerous reports indicating that antimicrobial resistance may be increasing among clinically significant bacteria in livestock and companion animals. As such, assessments of MDR presented in veterinary scientific reports are inconsistent. Herein, we apply previously standardized definitions for MDR, XDR and pandrug resistance (PDR) used in human medicine to animal pathogens and veterinary antimicrobial agents in which MDR is defined as an isolate that is not susceptible to at least one agent in at least three antimicrobial classes, XDR is defined as an isolate that is not susceptible to at least one agent in all but one or two available classes and PDR is defined as an isolate that is not susceptible to all agents in all available classes. These definitions may be applied to antimicrobial agents used to treat bovine respiratory disease (BRD) caused by Mannheimia haemolytica, Pasteurella multocida and Histophilus somni and swine respiratory disease (SRD) caused by Actinobacillus pleuropneumoniae, P. multocida and Streptococcus suis, as well as antimicrobial agents used to treat canine skin and soft tissue infections (SSTIs) caused by Staphylococcus and Streptococcus species. Application of these definitions in veterinary medicine should be considered static, whereas the classification of a particular resistance phenotype as MDR, XDR or PDR could change over time as more veterinary-specific clinical breakpoints or antimicrobial classes and/or agents become available in the future.

Serum antibodies in mares and foals to Actinobacillus equuli whole cells, outer membrane proteins, and Aqx toxin.

PubMed

Holyoak, G R; Smith, C M; Boyette, R; Montelongo, M; Wray, J H; Ayalew, S; Duggan, V E; Confer, A W

2007-08-15

Actinobacillus equuli is carried in the alimentary tract of mares and can cause severe septicemia of neonatal foals. A hemolytic subspecies, A. equuli subsp. haemolyticus, and a non-hemolytic subspecies, A. equuli subsp. equuli, have been identified. Hemolytic strains produce the RTX toxin Aqx. The purpose of this study was to demonstrate sequentially in two sets of mare-foal pairs antibodies to A. equuli whole bacterial cells, outer membrane proteins, and recombinant Aqx and to compare the transfer of antibodies to these antigens between mares and their foals. Two mare/foal sets of sera were evaluated. Cohort A consisted of 18 mare-foal pairs obtained in the spring of 2005. Cohort B consisted of 10 mare-foal pairs obtained in the spring of 2006. For both sets, mare and foal sera were obtained immediately after foaling and prior to nursing (time 0) as well as at 12 and 24h and daily thereafter for 7 days. For Cohort B, sera were also obtained 30 days after birth. At parturition all mares had detectable antibodies to A. equuli whole cells and outer membranes; however, of those mares, two in Cohort A had undetectable antibodies to Aqx and their foals likewise had undetectable anti-Aqx antibodies. Antibodies against whole cells, outer membrane proteins, and Aqx were readily transferred from mares to foals. In most cases, there were significant correlations (p<0.05) between antibodies against whole cells, outer membrane proteins, and Aqx in mares' sera at the time of parturition and foal sera 24 after birth. Antibodies against the three antigen preparations had declined insignificantly (p>0.05) by day 30.

Succinic acid production with Actinobacillus succinogenes: rate and yield analysis of chemostat and biofilm cultures.

PubMed

Brink, Hendrik Gideon; Nicol, Willie

2014-08-19

Succinic acid is well established as bio-based platform chemical with production quantities expecting to increase exponentially within the next decade. Actinobacillus succinogenes is by far the most studied wild organism for producing succinic acid and is known for high yield and titre during production on various sugars in batch culture. At low shear conditions continuous fermentation with A. succinogenes results in biofilm formation. In this study, a novel shear controlled fermenter was developed that enabled: 1) chemostat operation where self-immobilisation was opposed by high shear rates and, 2) in-situ removal of biofilm by increasing shear rates and subsequent analysis thereof. The volumetric productivity of the biofilm fermentations were an order of magnitude more than the chemostat runs. In addition the biofilm runs obtained substantially higher yields. Succinic acid to acetic acid ratios for chemostat runs were 1.28±0.2 g.g(-1), while the ratios for biofilm runs started at 2.4 g.g(-1) and increased up to 3.3 g.g(-1) as glucose consumption increased. This corresponded to an overall yield on glucose of 0.48±0.05 g.g(-1) for chemostat runs, while the yields varied between 0.63 g.g(-1) and 0.74 g.g(-1) for biofilm runs. Specific growth rates (μ) were shown to be severely inhibited by the formation of organic acids, with μ only 12% of μ(max) at a succinic acid titre of 7 g.L(-1). Maintenance production of succinic acid was shown to be dominant for the biofilm runs with cell based production rates (extracellular polymeric substance removed) decreasing as SA titre increases. The novel fermenter allowed for an in-depth bioreaction analysis of A. succinogenes. Biofilm cells achieve higher SA yields than suspended cells and allow for operation at higher succinic acid titre. Both growth and maintenance rates were shown to drastically decrease with succinic acid titre. The A. succinogenes biofilm process has vast potential, where self-induced high cell densities

Specific detection and identification of [Actinobacillus] muris by PCR using primers targeting the 16S-23S rRNA internal transcribed spacer regions.

PubMed

Benga, Laurentiu; Benten, W Peter M; Engelhardt, Eva; Gougoula, Christina; Sager, Martin

2013-08-01

[Actinobacillus] muris represents along with [Pasteurella] pneumotropica the most prevalent Pasteurellaceae species isolated from the laboratory mouse. Despite the biological and economic importance of Pasteurellaceae in relation to experimental animals, no molecular based methods for the identification of [A.] muris are available. The aim of the present investigation was to develop a PCR method allowing detection and identification of [A.] muris. In this assay, a Pasteurellaceae common forward primer based on a conserved region of the 16S rRNA gene was used in conjunction with two different reverse primers specific for [A.] muris, targeting the 16S-23S internal transcribed spacer sequences. The specificity of the assay was tested against 78 reference and clinical isolates of Pasteurellaceae, including 37 strains of [A.] muris. In addition, eight other mice associated bacterial species which could pose a diagnostic problem were included. The assay showed 100% sensitivity and 97.95% specificity. Identification of the clinical isolates was validated by ITS profiling and when necessary by 16S rRNA sequencing. This multiplex PCR represents the first molecular tool able to detect [A.] muris and may become a reliable alternative to the present diagnostic methods. Copyright © 2013 Elsevier B.V. All rights reserved.

An international collaborative study to determine the prevalence of contagious caprine pleuropneumonia by monoclonal antibody-based cELISA.

PubMed

Peyraud, Armelle; Poumarat, François; Tardy, Florence; Manso-Silván, Lucía; Hamroev, Karomatullo; Tilloev, Tillo; Amirbekov, Mullojon; Tounkara, Karim; Bodjo, Charles; Wesonga, Hezron; Nkando, Isabel Gacheri; Jenberie, Shiferaw; Yami, Martha; Cardinale, Eric; Meenowa, Deodass; Jaumally, Mahmad Reshad; Yaqub, Tahir; Shabbir, Muhammad Zubair; Mukhtar, Nadia; Halimi, Mohibullah; Ziay, Ghulam Mohammad; Schauwers, Willy; Noori, Hafizullah; Rajabi, Ali Madad; Ostrowski, Stéphane; Thiaucourt, François

2014-02-24

Few serological tests are available for detecting antibodies against Mycoplasma capricolum subsp. capripneumoniae, the causal agent of contagious caprine pleuropneumonia (CCPP). The complement fixation test, the test prescribed for international trade purposes, uses a crude antigen that cross-reacts with all the other mycoplasma species of the "mycoides cluster" frequently infecting goat herds. The lack of a more specific test has been a real obstacle to the evaluation of the prevalence and economic impact of CCPP worldwide. A new competitive ELISA kit for CCPP, based on a previous blocking ELISA, was formatted at CIRAD and used to evaluate the prevalence of CCPP in some regions of Kenya, Ethiopia, Mauritius, Tajikistan and Pakistan in an international collaborative study. The strict specificity of the test was confirmed in CCPP-free goat herds exposed to other mycoplasma species of the "mycoides cluster". Prevalence studies were performed across the enzootic range of the disease in Africa and Asia. Seroprevalence was estimated at 14.6% in the Afar region of Ethiopia, whereas all the herds presented for CCPP vaccination in Kenya tested positive (individual seroprevalence varied from 6 to 90% within each herd). In Mauritius, where CCPP emerged in 2009, nine of 62 herds tested positive. In Central Asia, where the disease was confirmed only recently, no positive animals were detected in the Wakhan District of Afghanistan or across the border in neighboring areas of Tajikistan, whereas seroprevalence varied between 2.7% and 44.2% in the other districts investigated and in northern Pakistan. The test was also used to monitor seroconversion in vaccinated animals. This newly formatted CCPP cELISA kit has retained the high specificity of the original kit. It can therefore be used to evaluate the prevalence of CCPP in countries or regions without vaccination programs. It could also be used to monitor the efficacy of vaccination campaigns as high-quality vaccines induce high

Identification of Actinobacillus actinomycetemcomitans, Treponema denticola and Porphyromonas gingivalis within human dental calculus: a pilot investigation.

PubMed

Calabrese, Nicolino; Galgut, Peter; Mordan, Nicola

2007-10-01

Dental calculus is considered to be simply a "plaque-retentive factor", and therefore only a secondary aetiological factor in the pathogenesis of periodontitis. Recent studies have suggested a more active role for calculus. Our objective was to demonstrate the presence of periodontal pathogens in the non-mineralised areas of supra- and subgingival dental calculus. Subjects for the study were derived from patients with substantial amounts of supragingival calculus in the lower anterior region who had moderate periodontal disease, having been referred to the periodontal department at the Eastman Dental Hospital for periodontal care. Calculus was removed in as large pieces as possible by the use of a sickle or a push scaler placed underneath the apical or facial border of the calculus and fracturing it from the tooth surface in a single stroke. The orientation and absence of dental plaque was confirmed using light microscopy for each sample prior to inclusion in this study. Samples were prepared for transmission electron microscopic (TEM) observation after immunogold staining with polyclonal antibodies for the presence of Actinobacillus actinomycetemcomitans (A. a.), Porphyromonas gingivalis (P. g.) and Treponema denticola (T. d.). Most of the samples contained at least one of the bacterial species examined, either in the lacunae or in the covering dental plaque. T. d. was the most frequently identified species and was found in nearly all of the subgingival samples, whilstA. a. was rarely observed. In this limited study, supra- and subgingival dental calculus appears to be capable of maintaining periodontal pathogens within the deep recesses of its structural lacunae and channels. Therefore, calculus could possibly play a relevant role in the aetiology and pathogenesis of periodontitis. The presence of T. d. in the majority of specimens requires further investigation as its pathogenic potential may be underestimated in current published microbiological research, and

A Na+-coupled C4-dicarboxylate transporter (Asuc_0304) and aerobic growth of Actinobacillus succinogenes on C4-dicarboxylates.

PubMed

Rhie, Mi Na; Yoon, Hyo Eun; Oh, Hye Yun; Zedler, Sandra; Unden, Gottfried; Kim, Ok Bin

2014-07-01

Actinobacillus succinogenes, which is known to produce large amounts of succinate during fermentation of hexoses, was able to grow on C4-dicarboxylates such as fumarate under aerobic and anaerobic conditions. Anaerobic growth on fumarate was stimulated by glycerol and the major product was succinate, indicating the involvement of fumarate respiration similar to succinate production from glucose. The aerobic growth on C4-dicarboxylates and the transport proteins involved were studied. Fumarate was oxidized to acetate. The genome of A. succinogenes encodes six proteins with similarity to secondary C4-dicarboxylate transporters, including transporters of the Dcu (C4-dicarboxylate uptake), DcuC (C4-dicarboxylate uptake C), DASS (divalent anion : sodium symporter) and TDT (tellurite resistance dicarboxylate transporter) family. From the cloned genes, Asuc_0304 of the DASS family protein was able to restore aerobic growth on C4-dicarboxylates in a C4-dicarboxylate-transport-negative Escherichia coli strain. The strain regained succinate or fumarate uptake, which was dependent on the electrochemical proton potential and the presence of Na(+). The transport had an optimum pH ~7, indicating transport of the dianionic C4-dicarboxylates. Transport competition experiments suggested substrate specificity for fumarate and succinate. The transport characteristics for C4-dicarboxylate uptake by cells of aerobically grown A. succinogenes were similar to those of Asuc_0304 expressed in E. coli, suggesting that Asuc_0304 has an important role in aerobic fumarate uptake in A. succinogenes. Asuc_0304 has sequence similarity to bacterial Na(+)-dicarboxylate cotransporters and contains the carboxylate-binding signature. Asuc_0304 was named SdcA (sodium-coupled C4-dicarboxylate transporter from A. succinogenes). © 2014 The Authors.

Optimal combinations of acute phase proteins for detecting infectious disease in pigs.

PubMed

Heegaard, Peter M H; Stockmarr, Anders; Piñeiro, Matilde; Carpintero, Rakel; Lampreave, Fermin; Campbell, Fiona M; Eckersall, P David; Toussaint, Mathilda J M; Gruys, Erik; Sorensen, Nanna Skall

2011-03-17

The acute phase protein (APP) response is an early systemic sign of disease, detected as substantial changes in APP serum concentrations and most disease states involving inflammatory reactions give rise to APP responses. To obtain a detailed picture of the general utility of porcine APPs to detect any disease with an inflammatory component seven porcine APPs were analysed in serum sampled at regular intervals in six different experimental challenge groups of pigs, including three bacterial (Actinobacillus pleuropneumoniae, Streptococcus suis, Mycoplasma hyosynoviae), one parasitic (Toxoplasma gondii) and one viral (porcine respiratory and reproductive syndrome virus) infection and one aseptic inflammation. Immunochemical analyses of seven APPs, four positive (C-reactive protein (CRP), haptoglobin (Hp), pig major acute phase protein (pigMAP) and serum amyloid A (SAA)) and three negative (albumin, transthyretin, and apolipoprotein A1 (apoA1)) were performed in the more than 400 serum samples constituting the serum panel. This was followed by advanced statistical treatment of the data using a multi-step procedure which included defining cut-off values and calculating detection probabilities for single APPs and for APP combinations. Combinations of APPs allowed the detection of disease more sensitively than any individual APP and the best three-protein combinations were CRP, apoA1, pigMAP and CRP, apoA1, Hp, respectively, closely followed by the two-protein combinations CRP, pigMAP and apoA1, pigMAP, respectively. For the practical use of such combinations, methodology is described for establishing individual APP threshold values, above which, for any APP in the combination, ongoing infection/inflammation is indicated.

Plasma concentrations resulting from florfenicol preparations given to pigs in their drinking water.

PubMed

Gutiérrez, L; Vargas, D; Ocampo, L; Sumano, H; Martinez, R; Tapia, G

2011-09-01

Florfenicol administered through the drinking water has been recommended as a metaphylactic antibacterial drug to control outbreaks of respiratory diseases in pigs caused by strains of Actinobacillus pleuropneumoniae and Pasteurella multocida, yet it is difficult to pinpoint in practice when the drug is given metaphylactically or therapeutically. Further, pigs are likely to reject florfenicol-medicated water, and plasma concentrations of the drug are likely to be marginal for diseases caused by Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus. The reported minimal inhibitory concentration (MIC) values for these organisms show a breakpoint of 2 to 3 μg/mL. An experiment was conducted during September and October 2009. One hundred twenty healthy crossbred pigs (Landrace-Yorkshire), weighing 23 ± 6.2 kg, were used in this trial. They were randomly assigned to 5 groups, with 3 replicates of 8 animals/group. Two commercial preparations of florfenicol were administered through the drinking water at 2 concentrations (0.01 and 0.015%). Water intake was measured before and after medication, and plasma concentrations of florfenicol were determined by HPLC. Considerable rejection of florfenicol-medicated water was observed. However, plasma florfenicol concentrations were of a range sufficient for a methaphylaxis approach to preventing disease by bacteria, with MIC breakpoints of ≤ 0.25 μg/mL. Decreased efficacy as a metaphylactic medication should be expected for bacteria with MIC >0.25 μg/mL, considering the reported existence of bacteria resistant to florfenicol and the natural resistance of Streptococcus suis or E. coli to this drug.

Tilmicosin- and florfenicol-loaded hydrogenated castor oil-solid lipid nanoparticles to pigs: Combined antibacterial activities and pharmacokinetics.

PubMed

Ling, Z; Yonghong, L; Junfeng, L; Li, Z; Xianqiang, L

2018-04-01

The combined antibacterial effects of tilmicosin (TIL) and florfenicol (FF) against Actinobacillus pleuropneumoniae (APP) (n = 2), Streptococcus suis (S. suis) (n = 2), and Haemophilus parasuis (HPS) (n = 2) were evaluated by chekerboard test and time-kill assays. The pharmacokinetics (PKs) of TIL- and FF-loaded hydrogenated castor oil (HCO)-solid lipid nanoparticles (SLN) were performed in healthy pigs. The results indicated that TIL and FF showed synergistic or additive antibacterial activities against APP, S. suis and HPS with the fractional inhibitory concentration (FIC) ranging from 0.375 to 0.75. The time-kill assays showed that 1/2 minimum inhibitory concentration (MIC) TIL combined with 1/2 MIC FF had a stronger ability to inhibit the growth of APP, S. suis, and HPS than 1 MIC TIL or 1 MIC FF, respectively. After oral administration, plasma TIL and FF concentrations could maintain about 0.1 μg/ml for 192 and 176 hr. The SLN prolonged the last time point with detectable concentrations (T last ), area under the concentration-time curve (AUC 0-t ), elimination half-life (T ½ke ), and mean residence time (MRT) by 3.1, 5.6, 12.7, 3.4-fold of the active pharmaceutical ingredient (API) of TIL and 11.8, 16.5, 18.1, 12.1-fold of the API of FF, respectively. This study suggests that the TIL-FF-SLN could be a useful oral formulation for the treatment of APP, S. suis, and HPS infection in pigs. © 2017 John Wiley & Sons Ltd.

Willingness to pay for contagious bovine pleuropneumonia vaccination in Narok South District of Kenya.

PubMed

Kairu-Wanyoike, Salome W; Kaitibie, Simeon; Heffernan, Claire; Taylor, Nick M; Gitau, George K; Kiara, Henry; McKeever, Declan

2014-08-01

Contagious bovine pleuropneumonia (CBPP) is an economically important trans-boundary cattle disease which affects food security and livelihoods. A conjoint analysis-contingent valuation was carried out on 190 households in Narok South District of Kenya to measure willingness to pay (WTP) and demand for CBPP vaccine and vaccination as well as factors affecting WTP. The mean WTP was calculated at Kenya Shillings (KSh) 212.48 (USD 3.03) for vaccination using a vaccine with the characteristics that were preferred by the farmers (preferred vaccine and vaccination) and KSh -71.45 (USD -1.02) for the currently used vaccine and vaccination. The proportion of farmers willing to pay an amount greater than zero was 66.7% and 34.4% for the preferred and current vaccine and vaccination respectively. About one third (33.3%) of farmers would need to be compensated an average amount of KSh 1162.62 (USD 13.68) per animal to allow their cattle to be vaccinated against CBPP using the preferred vaccine and vaccination. About two-thirds (65.6%) of farmers would need to be compensated an average amount of KSh 853.72 (USD 12.20) per animal to allow their cattle to be vaccinated against CBPP using the current vaccine and vaccination. The total amount of compensation would be KSh 61.39 million (USD 0.88 million) for the preferred vaccine and vaccination and KSh 90.15 million (USD 1.29 million) for the current vaccine and vaccination. Demand curves drawn from individual WTP demonstrated that only 59% and 27% of cattle owners with a WTP greater than zero were willing to pay a benchmark cost of KSh 34.60 for the preferred and current vaccine respectively. WTP was negatively influenced by the attitude about household economic situation (p=0.0078), presence of cross breeds in the herd (p<0.0001) and years since CBPP had been experienced in the herd (p=0.0375). It was positively influenced by education (p=0.0251) and the practice of treating against CBPP (p=0.0432). The benefit cost ratio (BCR

Willingness to pay for contagious bovine pleuropneumonia vaccination in Narok South District of Kenya

PubMed Central

Kairu-Wanyoike, Salome W.; Kaitibie, Simeon; Heffernan, Claire; Taylor, Nick M.; Gitau, George K.; Kiara, Henry; McKeever, Declan

2014-01-01

Contagious bovine pleuropneumonia (CBPP) is an economically important trans-boundary cattle disease which affects food security and livelihoods. A conjoint analysis–contingent valuation was carried out on 190 households in Narok South District of Kenya to measure willingness to pay (WTP) and demand for CBPP vaccine and vaccination as well as factors affecting WTP. The mean WTP was calculated at Kenya Shillings (KSh) 212.48 (USD 3.03) for vaccination using a vaccine with the characteristics that were preferred by the farmers (preferred vaccine and vaccination) and KSh −71.45 (USD −1.02) for the currently used vaccine and vaccination. The proportion of farmers willing to pay an amount greater than zero was 66.7% and 34.4% for the preferred and current vaccine and vaccination respectively. About one third (33.3%) of farmers would need to be compensated an average amount of KSh 1162.62 (USD 13.68) per animal to allow their cattle to be vaccinated against CBPP using the preferred vaccine and vaccination. About two-thirds (65.6%) of farmers would need to be compensated an average amount of KSh 853.72 (USD 12.20) per animal to allow their cattle to be vaccinated against CBPP using the current vaccine and vaccination. The total amount of compensation would be KSh 61.39 million (USD 0.88 million) for the preferred vaccine and vaccination and KSh 90.15 million (USD 1.29 million) for the current vaccine and vaccination. Demand curves drawn from individual WTP demonstrated that only 59% and 27% of cattle owners with a WTP greater than zero were willing to pay a benchmark cost of KSh 34.60 for the preferred and current vaccine respectively. WTP was negatively influenced by the attitude about household economic situation (p = 0.0078), presence of cross breeds in the herd (p < 0.0001) and years since CBPP had been experienced in the herd (p = 0.0375). It was positively influenced by education (p = 0.0251) and the practice of treating against CBPP (p = 0.0432). The

Prevalence of O1/K1- and O2/K3-Reactive Actinobacillus suis in Healthy and Diseased Swine

PubMed Central

Slavić, ĐurĐa; Toffner, Tania L.; Monteiro, Mario A.; Perry, Malcolm B.; MacInnes, Janet I.

2000-01-01

A cell surface antigen-typing system was devised for the swine pathogen Actinobacillus suis and used to examine the prevalence of different lipopolysaccharide (O) types in healthy and diseased pigs. The strains examined in this study were isolated from a variety of locations in Canada and from Kansas. Lipopolysaccharide preparations of 151 isolates of A. suis were characterized by immunoblotting using polyclonal antisera generated to strains SO4 (O1/K1), H89-1173 (O2/K3), and VSB 3714, a rough strain. Approximately 54% (62 of 114) of A. suis isolates from diseased pigs, all (11 of 11) isolates from healthy pigs, and all (4 of 4) reference strains reacted with O1/K1 antiserum. More than 80% (18 of 22) of A. suis strains used for bacterin production and approximately 41% (47 of 114) of isolates from diseased pigs bound O2/K3 antiserum. One isolate appeared to be rough, and five were untypeable. O1/K1- and O2/K3-reactive strains were equally prevalent in Kansas, whereas O2/K3-reactive strains were more common in Québec and western Canada and O1/K1 strains were most common in Ontario. The fact that virtually all of the strains submitted for bacterin production were O2/K3-reactive strains is consistent with the notion that these strains may be more virulent than O1/K1 strains; alternatively, this may reflect geographic or other biases. In addition, we observed cross-reactivity between A. suis cell surface antigens and swine antisera to several other important pathogens. This finding may explain why previous attempts to develop a simple serodiagnostic test for A. suis have been unsuccessful. PMID:11015398

In vitro activity of five tetracyclines and some other antimicrobial agents against four porcine respiratory tract pathogens.

PubMed

Pijpers, A; Van Klingeren, B; Schoevers, E J; Verheijden, J H; Van Miert, A S

1989-09-01

The minimal inhibitory concentrations (MIC) of five tetracyclines and ten other antimicrobial agents were determined for four porcine bacterial respiratory tract pathogens by the agar dilution method. For the following oxytetracycline-susceptible strains, the MIC50 ranges of the tetracyclines were: P. multocida (n = 17) 0.25-0.5 micrograms/ml; B. bronchiseptica (n = 20) 0.25-1.0 micrograms/ml; H. pleuropneumoniae (n = 20) 0.25-0.5 micrograms/ml; S. suis Type 2 (n = 20) 0.06-0.25 micrograms/ml. For 19 oxytetracycline-resistant P. multocida strains the MIC50 of the tetracyclines varied from 64 micrograms/ml for oxytetracycline to 0.5 micrograms/ml for minocycline. Strikingly, minocycline showed no cross-resistance with oxytetracycline, tetracycline, chlortetracycline and doxycycline in P. multocida and in H. pleuropneumoniae. Moreover, in susceptible strains minocycline showed the highest in vitro activity followed by doxycycline. Low MIC50 values were observed for chloramphenicol, ampicillin, flumequine, ofloxacin and ciprofloxacin against P. multocida and H. pleuropneumoniae. B. bronchiseptica was moderately susceptible or resistant to these compounds. As expected tiamulin, lincomycin, tylosin and spiramycin were not active against H. pleuropneumoniae. Except for flumequine, the MIC50 values of nine antimicrobial agents were low for S. suis Type 2. Six strains of this species showed resistance to the macrolides and lincomycin.

Genetic evolution of Mycoplasma capricolum subsp. capripneumoniae strains and molecular epidemiology of contagious caprine pleuropneumonia by sequencing of locus H2.

PubMed

Lorenzon, S; Wesonga, H; Ygesu, Laikemariam; Tekleghiorgis, Tesfaalem; Maikano, Y; Angaya, M; Hendrikx, P; Thiaucourt, F

2002-03-01

Contagious caprine pleuropneumonia (CCPP) is a major threat to goat farming in developing countries. Its exact distribution is not well known, despite the fact that new diagnostic tools such as PCR and competitive ELISA are now available. The authors developed a study of the molecular epidemiology of the disease, based on the amplification of a 2400 bp long fragment containing two duplicated gene coding for a putative membrane protein. The sequence of this fragment, obtained on 19 Mycoplasma capricolum subsp. capripneumoniae (Mccp) strains from various geographical locations, gave 11 polymorphic positions. The three mutations found on gene H2prim were silent and did not appear to induce any amino acid modifications in the putative translated protein. The second gene may be a pseudogene not translated in vivo, as it bore a deletion of the ATG codon found in the other members of the "Mycoplasma mycoides cluster" and as the six mutations evidenced in the Mccp strains would induce modifications in the translated amino acids. In addition, an Mccp strain isolated in the United Arab Emirates showed a deletion of the whole pseudogene, a further indication that this gene is not compulsory for mycoplasma growth. Four lineages were defined, based on the nucleotide sequence. These correlated relatively well with the geographical origin of the strains: North, Central or East Africa. The strain of Turkish origin had a sequence similar to that found in North African strains, while strains isolated in Oman had sequences similar to those of North or East African strains. The latter is possibly due to the regular import of goats of various origins. Similar molecular epidemiology tools have been developed by sequencing the two operons of the 16S rRNA gene or by AFLP. All these various techniques give complementary results. One (16S rRNA) offers the likelihood of a finer identification of strains circulating in a region, another (H2) of determining the geographical origin of the

Biofilm formation by virulent and non-virulent strains of Haemophilus parasuis.

PubMed

Bello-Ortí, Bernardo; Deslandes, Vincent; Tremblay, Yannick D N; Labrie, Josée; Howell, Kate J; Tucker, Alexander W; Maskell, Duncan J; Aragon, Virginia; Jacques, Mario

2014-11-27

Haemophilus parasuis is a commensal bacterium of the upper respiratory tract of healthy pigs. It is also the etiological agent of Glässer's disease, a systemic disease characterized by polyarthritis, fibrinous polyserositis and meningitis, which causes high morbidity and mortality in piglets. The aim of this study was to evaluate biofilm formation by well-characterized virulent and non-virulent strains of H. parasuis. We observed that non-virulent strains isolated from the nasal cavities of healthy pigs formed significantly (p < 0.05) more biofilms than virulent strains isolated from lesions of pigs with Glässer's disease. These differences were observed when biofilms were formed in microtiter plates under static conditions or formed in the presence of shear force in a drip-flow apparatus or a microfluidic system. Confocal laser scanning microscopy using different fluorescent probes on a representative subset of strains indicated that the biofilm matrix contains poly-N-acetylglucosamine, proteins and eDNA. The biofilm matrix was highly sensitive to degradation by proteinase K. Comparison of transcriptional profiles of biofilm and planktonic cells of the non-virulent H. parasuis F9 strain revealed a significant number of up-regulated membrane-related genes in biofilms, and genes previously identified in Actinobacillus pleuropneumoniae biofilms. Our data indicate that non-virulent strains of H. parasuis have the ability to form robust biofilms in contrast to virulent, systemic strains. Biofilm formation might therefore allow the non-virulent strains to colonize and persist in the upper respiratory tract of pigs. Conversely, the planktonic state of the virulent strains might allow them to disseminate within the host.

Efficiency of different air filter types for pig facilities at laboratory scale.

PubMed

Wenke, Cindy; Pospiech, Janina; Reutter, Tobias; Truyen, Uwe; Speck, Stephanie

2017-01-01

Air filtration has been shown to be efficient in reducing pathogen burden in circulating air. We determined at laboratory scale the retention efficiency of different air filter types either composed of a prefilter (EU class G4) and a secondary fiberglass filter (EU class F9) or consisting of a filter mat (EU class M6 and F8-9). Four filter prototypes were tested for their capability to remove aerosol containing equine arteritis virus (EAV), porcine reproductive and respiratory syndrome virus (PRRSV), bovine enterovirus 1 (BEV), Actinobacillus pleuropneumoniae (APP), and Staphylococcus (S.) aureus from air. Depending on the filter prototype and utilisation, the airflow was set at 1,800 m3/h (combination of upstream prefilter and fiberglass filter) or 80 m3/h (filter mat). The pathogens were aerosolized and their concentration was determined in front of and behind the filter by culture or quantitative real-time RT-PCR. Furthermore, survival of the pathogens over time in the filter material was determined. Bacteria were most efficiently filtered with a reduction rate of up to 99.9% depending on the filter used. An approximately 98% reduction was achieved for the viruses tested. Viability or infectivity of APP or PRRSV in the filter material decreased below the detection limit after 4 h and 24 h, respectively, whereas S. aureus was still culturable after 4 weeks. Our results demonstrate that pathogens can efficiently be reduced by air filtration. Consequently, air filtration combined with other strict biosecurity measures markedly reduces the risk of introducing airborne transmitted pathogens to animal facilities. In addition, air filtration might be useful in reducing bioaerosols within a pig barn, hence improving respiratory health of pigs.

Association of swine influenza H1N1 pandemic virus (SIV-H1N1p) with porcine respiratory disease complex in sows from commercial pig farms in Colombia.

PubMed

Jiménez, Luisa Fernanda Mancipe; Ramírez Nieto, Gloria; Alfonso, Victor Vera; Correa, Jairo Jaime

2014-08-01

Porcine respiratory disease complex (PRDC) is a serious health problem that mainly affects growing and finishing pigs. PRDC is caused by a combination of viral and bacterial agents, such as porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza virus (SIV), Mycoplasma hyopneumoniae (Myh), Actinobacillus pleuropneumoniae (APP), Pasteurella multocida and Porcine circovirus 2 (PCV2). To characterize the specific role of swine influenza virus in PRDC presentation in Colombia, 11 farms from three major production regions in Colombia were examined in this study. Nasal swabs, bronchial lavage and lung tissue samples were obtained from animals displaying symptoms compatible with SIV. Isolation of SIV was performed in 9-day embryonated chicken eggs or Madin-Darby Canine Kidney (MDCK) cells. Positive isolates, identified via the hemagglutination inhibition test, were further analyzed using PCR. Overall, 7 of the 11 farms were positive for SIV. Notably, sequencing of the gene encoding the hemagglutinin (HA) protein led to grouping of strains into circulating viruses identified during the human outbreak of 2009, classified as pandemic H1N1-2009. Serum samples from 198 gilts and multiparous sows between 2008 and 2009 were obtained to determine antibody presence of APP, Myh, PCV2 and PRRSV in both SIV-H1N1p-negative and -positive farms, but higher levels were recorded for SIV-H1N1p-positive farms. Odds ratio (OR) and P values revealed statistically significant differences (p<0.05) in PRDC presentation in gilts and multiparous sows of farms positive for SIV-H1N1p. Our findings indicate that positive farms have increased risk of PRDC presentation, in particular, PCV2, APP and Myh.

Survey for selected pathogens in wild pigs (Sus scrofa) from Guam, Marianna Islands, USA.

PubMed

Cleveland, Christopher A; DeNicola, Anthony; Dubey, J P; Hill, Dolores E; Berghaus, Roy D; Yabsley, Michael J

2017-06-01

Pigs (Sus scrofa) were introduced to Guam in the 1600's and are now present in high densities throughout the island. Wild pigs are reservoirs for pathogens of concern to domestic animals and humans. Exposure to porcine parvovirus, transmissible gastroenteritis, and Leptospira interrogans has been documented in domestic swine but data from wild pigs are lacking. The close proximity of humans, domestic animals, and wild pigs, combined with the liberal hunting of wild pigs, results in frequent opportunities for pathogen transmission. From February-March 2015, blood, tissue and ectoparasite samples were collected from 47 wild pigs. Serologic testing found exposure to Brucella spp. (2%), Toxoplasma gondii (11%), porcine reproductive and respiratory syndrome (PRRS) virus (13%), porcine circovirus type 2 (36%), pseudorabies virus (64%), Actinobacillus pleuropneumoniae (93%), Lawsonia intracellularis (93%), and porcine parvovirus (94%). Eleven (24%) samples had low titers (1:100) to Leptospira interrogans serovars Bratislava (n=6), Icterohaemorrhagiae (n=6), Pomona (n=2), and Hardjo (n=1). Kidney samples from nine pigs with Leptospira antibodies were negative for Leptospira antigens. Numerous pigs had Metastrongylus lungworms and three had Stephanurus dentatus. Lice (Hematopinus suis) and ticks (Amblyomma breviscutatum) were also detected. No antibodies to Influenza A viruses were detected. In contrast to the previous domestic swine survey, we found evidence of numerous pathogens in wild pigs including new reports of pseudorabies virus, PRRS virus, Brucella, and Leptospira in pigs on Guam. These findings highlight that domestic swine-wild pig interactions should be prevented and precautions are needed when handling wild pigs to minimize the risk of pathogen transmission. Copyright © 2017 Elsevier B.V. All rights reserved.

Impact of different supply air and recirculating air filtration systems on stable climate, animal health, and performance of fattening pigs in a commercial pig farm

PubMed Central

Wenke, Cindy; Pospiech, Janina; Reutter, Tobias; Altmann, Bettina; Truyen, Uwe

2018-01-01

Biosecurity is defined as the implementation of measures that reduce the risk of disease agents being introduced and/or spread. For pig production, several of these measures are routinely implemented (e.g. cleaning, disinfection, segregation). However, air as a potential vector of pathogens has long been disregarded. Filters for incoming and recirculating air were installed into an already existing ventilation plant at a fattening piggery (3,840 pigs at maximum) in Saxony, Germany. Over a period of three consecutive fattening periods, we evaluated various parameters including air quality indices, environmental and operating parameters, and pig performance. Animal data regarding respiratory diseases, presence of antibodies against influenza A viruses, PRRSV, and Actinobacillus pleuropneumoniae and lung health score at slaughter were recorded, additionally. There were no significant differences (p = 0.824) in total bacterial counts between barns with and without air filtration. Recirculating air filtration resulted in the lowest total dust concentration (0.12 mg/m3) and lung health was best in animals from the barn equipped with recirculating air filtration modules. However, there was no difference in animal performance. Antibodies against all above mentioned pathogens were detected but mostly animals were already antibody-positive at re-stocking. We demonstrated that supply air filtration as well as recirculating air filtration technique can easily be implemented in an already existing ventilation system and that recirculating air filtration resulted in enhanced lung health compared to supply air-filtered and non-filtered barns. A more prominent effect might have been obtained in a breeding facility because of the longer life span of sows and a higher biosecurity level with air filtration as an add-on measure. PMID:29558482

Attachment of Actinobacillus suis H91-0380 and Its Isogenic Adhesin Mutants to Extracellular Matrix Components of the Tonsils of the Soft Palate of Swine

PubMed Central

Bujold, Adina R.

2016-01-01

Tonsils conduct immune surveillance of antigens entering the upper respiratory tract. Despite their immunological function, they are also sites of persistence and invasion of bacterial pathogens. Actinobacillus suis is a common resident of the tonsils of the soft palate in pigs, but under certain circumstances it can invade, causing septicemia and related sequelae. Twenty-four putative adhesins are predicted in the A. suis genome, but to date, little is known about how they might participate in colonization or invasion. To better understand these processes, swine tonsil lysates were characterized by mass spectrometry. Fifty-nine extracellular matrix (ECM) proteins were identified, including small leucine-rich proteoglycans, integrins, and other cell surface receptors. Additionally, attachment of the wild type and 3 adhesin mutants to 5 ECM components was evaluated. Exponential cultures of wild-type A. suis adhered significantly more than stationary cultures to all ECM components studied except collagen I. During exponential growth, the A. suis Δflp1 mutant attached less to collagen IV while the ΔompA mutant attached less to all ECMs. The ΔcomE1 strain attached less to collagen IV, fibronectin, and vitronectin during exponential growth and exhibited differential attachment to collagen I over short adherence time points. These results suggest that Flp1, OmpA, and ComE1 are important during early stages of attachment to ECM components found in tonsils, which supports the notion that other adhesins have compensatory effects during later stages of attachment. PMID:27481253

Effect of treatment on titer, function, and antigen recognition of serum antibodies to Actinobacillus actinomycetemcomitans in patients with rapidly progressive periodontitis.

PubMed Central

Sjöström, K; Ou, J; Whitney, C; Johnson, B; Darveau, R; Engel, D; Page, R C

1994-01-01

Although periodontal treatment by scaling and root planing (SCRP) is known to induce bacteremia, the effect of this procedure on the host immune response is not known. We have determined pre- and post-SCRP immunoglobulin G antibody titers to antigens of Actinobacillus actinomycetemcomitans in the sera of 22 patients with rapidly progressive periodontitis. We also assessed the ability of these sera to enhance phagocytosis and killing of A. actinomycetemcomitans by human polymorphonuclear leukocytes by using a polymorphonuclear leukocyte chemiluminescence (CL) assay. Specific anti-A. actinomycetemcomitans antibody titers were significantly increased at 6 and 12 months after beginning treatment, and CL values were significantly increased at 12 months, whereas mean interproximal pocket depths were significantly decreased at 12 months after beginning treatment. When patients were classified as either seropositive (twice the median titer of control subjects; n = 10) or seronegative (n = 12), both median titers and CL values were significantly increased for the seronegative group at 6 and 12 months after treatment. In the seropositive group, only the median titer was significantly increased at 12 months. Western blot (immunoblot) patterns for six seronegative and six seropositive patients differed remarkably at the baseline. Before treatment, all of the seropositive patients recognized high-molecular-mass lipopolysaccharide (LPS) and a large number of protein components. Patterns were virtually unaffected by therapy. Before treatment, only one of the seronegative patients recognized the LPS smear and none reacted strongly with protein components. Following treatment, slight LPS staining was observed for five of six seronegative patients and detection of protein bands was enhanced in all cases. We conclude that treatment by SCRP induces a humoral immune response, especially in seronegative patients, and that response may play a role in the observed beneficial effects of

Actinobacillus actinomycetemcomitans Y4 capsular polysaccharide induces IL-1β mRNA expression through the JNK pathway in differentiated THP-1 cells

PubMed Central

Iwata, T; Mitani, A; Ishihara, Y; Tanaka, S; Yamamoto, G; Kikuchi, T; Naganawa, T; Matsumura, Y; Suga, T; Koide, M; Sobue, T; Suzuki, T; Noguchi, T

2005-01-01

Capsular polysaccharide from Actinobacillus actinomycetemcomitans Y4 (Y4 CP) induces bone resorption in a mouse organ culture system and osteoclast formation in mouse bone marrow cultures, as reported in previous studies. We also found that Y4 CP inhibits the release of interleukin (IL)-6 and IL-8 from human gingival fibroblast (HGF). Thus Y4 CP induces various responses in localized tissue and leads to the secretion of several cytokines. However, the effects of Y4 CP on human monocytes/macrophages are still unclear. In this study, THP-1 cells, which are a human monocytic cell line, were stimulated with Y4 CP, and we measured gene expression in inflammatory cytokine and signal transduction pathways. IL-1β and tumour necrosis factor (TNF)-α mRNA were induced from Y4 CP-treated THP-1 cells. IL-1β mRNA expression was increased according to the dose of Y4 CP, and in a time-dependent manner. IL-1β mRNA expression induced by Y4 CP (100 µg/ml) was approximately 7- to 10-fold greater than that in the control by real-time PCR analysis. Furthermore, neither PD98059, a specific inhibitor of extracellular signal-regulated kinase nor SB203580, a specific inhibitor of p38 kinase prevented the IL-1β expression induced by Y4 CP. However, JNK Inhibitor II, a specific inhibitor of c-Jun N-terminal kinase (JNK) prevented the IL-1β mRNA expression induced by Y4 CP in a concentration-dependent manner. These results indicate that Y4 CP-mediated JNK pathways play an important role in the regulation of IL-1β mRNA. Therefore, Y4 CP-transduced signals for IL-1β induction in the antibacterial action of macrophages may provide a therapeutic strategy for periodontitis. PMID:15996190

Efficiency of different air filter types for pig facilities at laboratory scale

PubMed Central

Wenke, Cindy; Pospiech, Janina; Reutter, Tobias; Truyen, Uwe

2017-01-01

Air filtration has been shown to be efficient in reducing pathogen burden in circulating air. We determined at laboratory scale the retention efficiency of different air filter types either composed of a prefilter (EU class G4) and a secondary fiberglass filter (EU class F9) or consisting of a filter mat (EU class M6 and F8-9). Four filter prototypes were tested for their capability to remove aerosol containing equine arteritis virus (EAV), porcine reproductive and respiratory syndrome virus (PRRSV), bovine enterovirus 1 (BEV), Actinobacillus pleuropneumoniae (APP), and Staphylococcus (S.) aureus from air. Depending on the filter prototype and utilisation, the airflow was set at 1,800 m3/h (combination of upstream prefilter and fiberglass filter) or 80 m3/h (filter mat). The pathogens were aerosolized and their concentration was determined in front of and behind the filter by culture or quantitative real-time RT-PCR. Furthermore, survival of the pathogens over time in the filter material was determined. Bacteria were most efficiently filtered with a reduction rate of up to 99.9% depending on the filter used. An approximately 98% reduction was achieved for the viruses tested. Viability or infectivity of APP or PRRSV in the filter material decreased below the detection limit after 4 h and 24 h, respectively, whereas S. aureus was still culturable after 4 weeks. Our results demonstrate that pathogens can efficiently be reduced by air filtration. Consequently, air filtration combined with other strict biosecurity measures markedly reduces the risk of introducing airborne transmitted pathogens to animal facilities. In addition, air filtration might be useful in reducing bioaerosols within a pig barn, hence improving respiratory health of pigs. PMID:29028843

Improvement of technical results following use of Ingelvac CircoFLEX in a Dutch organic breeding and fattening farm: a case report.

PubMed

Schlepers, M; Gelauf, J; Wertenbroek, N; Nielen, M

2013-07-01

Porcine Circovirus type 2 (PCV2) is a ubiquitous infection and major cause of production loss for the pig industry. The aim of this study was to evaluate the effect of vaccination against PCV2 on technical results of pigs on an organic breeding and fattening farm, focussing on growth and mortality of weaned piglets and fattening pigs. The study was based on retrospective data between January 2009 and May 2011. During the study period, three subsequent vaccination strategies were used: 1. Stellamune One, 2. Stellamune One+CircoFLEX, 3. MycoFLEX+CircoFLEX. From these three periods, the corresponding management- and slaughterhouse data were analysed by an ANOVA-test. Due to few data in period 2 and an outbreak of Actinobacillus pleuropneumoniae during periods 2 and 3, these two periods were combined in one period and analysed by a two-sample t-test. Mortality of weaned piglets decreased with 3.6% (0.6 - 6.6%) (P0.023) in comparison to period 1 and average daily weight gain improved by 21 gram (7 - 34 gram) (P0.004) in periods 2 and 3. Mortality of fattening pigs was 2.3% (1.2 - 3.5%) (P0.001) less than in period 1 and corrected energy conversion rate improved 0.27 (0.05 - 0.49) (P0.017). There was no significant effect on slaughterhouse parameters. In conclusion, vaccination against PCV2 improved technical results of weaned and fattening pigs on this farm. The advantage of vaccination with MycoFLEX+CircoFLEX instead of Stellamune One+CircoFLEX is that the two FLEX-vaccines can be mixed and administered as a one shot vaccine, reducing work load and animal stressors.

Monitoring of antimicrobial susceptibility of respiratory tract pathogens isolated from diseased cattle and pigs across Europe, 2009-2012: VetPath results.

PubMed

El Garch, Farid; de Jong, Anno; Simjee, Shabbir; Moyaert, Hilde; Klein, Ulrich; Ludwig, Carolin; Marion, Hervé; Haag-Diergarten, Silke; Richard-Mazet, Alexandra; Thomas, Valérie; Siegwart, Ed

2016-10-15

VetPath is an ongoing pan-European antibiotic susceptibility monitoring programme that collects pathogens from diseased cattle, pigs and poultry. In the current study, 996 isolates from cattle and pig respiratory tract infections were tested for their antimicrobial susceptibilities. Non-replicate lung samples or nasopharyngeal/nasal swabs were collected from animals with acute clinical signs in 10 countries during 2009-2012. Pasteurella multocida, Mannheimia haemolytica and Histophilus somni from cattle and P. multocida, Actinobacillus pleuropneumoniae, Haemophilus parasuis, Bordetella bronchiseptica and Streptococcus suis from pigs were isolated by standard methods. S. suis was also isolated from meningitis cases. MIC values of 16 or 17 antibiotics were assessed centrally by broth microdilution following CLSI standards. Results were interpreted using CLSI breakpoints where available. Cattle isolates were generally highly susceptible to most antibiotics, except to tetracycline (3.0-12.0% resistance). Low levels of resistance (0-4.0%) were observed for the macrolide antibiotics. Resistance to spectinomycin varied from 0 to 6.0%. In pig isolates similar observations were made. Resistance to amoxicillin/clavulanic acid, ceftiofur, enrofloxacin, florfenicol, tulathromycin, tiamulin and tilmicosin was absent or <2%. Trimethoprim/sulfamethoxazole resistance varied from 1.9 to 5.3%, but tetracycline resistance varied from 20.4% in P. multocida to 88.1% in S. suis. For most antibiotics and pathogens the percentage resistance remained unchanged or only increased numerically as compared to that of the period 2002-2006. In conclusion, absence or low resistance to antibiotics with defined clinical breakpoints, except for tetracycline, was observed among the major respiratory tract pathogens recovered from livestock. Comparison of all antibiotics and organisms was hampered since for almost half of the antibiotics no CLSI-defined breakpoints were available. Copyright © 2016

Severity of Bovine Tuberculosis Is Associated with Co-Infection with Common Pathogens in Wild Boar

PubMed Central

Risco, David; Serrano, Emmanuel; Fernández-Llario, Pedro; Cuesta, Jesús M.; Gonçalves, Pilar; García-Jiménez, Waldo L.; Martínez, Remigio; Cerrato, Rosario; Velarde, Roser; Gómez, Luis; Segalés, Joaquím; Hermoso de Mendoza, Javier

2014-01-01

Co-infections with parasites or viruses drive tuberculosis dynamics in humans, but little is known about their effects in other non-human hosts. This work aims to investigate the relationship between Mycobacterium bovis infection and other pathogens in wild boar (Sus scrofa), a recognized reservoir of bovine tuberculosis (bTB) in Mediterranean ecosystems. For this purpose, it has been assessed whether contacts with common concomitant pathogens are associated with the development of severe bTB lesions in 165 wild boar from mid-western Spain. The presence of bTB lesions affecting only one anatomic location (cervical lymph nodes), or more severe patterns affecting more than one location (mainly cervical lymph nodes and lungs), was assessed in infected animals. In addition, the existence of contacts with other pathogens such as porcine circovirus type 2 (PCV2), Aujeszky's disease virus (ADV), swine influenza virus, porcine reproductive and respiratory syndrome virus, Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, Haemophilus parasuis and Metastrongylus spp, was evaluated by means of serological, microbiological and parasitological techniques. The existence of contacts with a structured community of pathogens in wild boar infected by M. bovis was statistically investigated by null models. Association between this community of pathogens and bTB severity was examined using a Partial Least Squares regression approach. Results showed that adult wild boar infected by M. bovis had contacted with some specific, non-random pathogen combinations. Contact with PCV2, ADV and infection by Metastrongylus spp, was positively correlated to tuberculosis severity. Therefore, measures against these concomitant pathogens such as vaccination or deworming, might be useful in tuberculosis control programmes in the wild boar. However, given the unexpected consequences of altering any community of organisms, further research should evaluate the impact of such measures under

Background characterization of an ultra-low background liquid scintillation counter

DOE PAGES

Erchinger, J. L.; Orrell, John L.; Aalseth, C. E.; ...

2017-01-26

The Ultra-Low Background Liquid Scintillation Counter developed by Pacific Northwest National Laboratory will expand the application of liquid scintillation counting by enabling lower detection limits and smaller sample volumes. By reducing the overall count rate of the background environment approximately 2 orders of magnitude below that of commercially available systems, backgrounds on the order of tens of counts per day over an energy range of ~3–3600 keV can be realized. Finally, initial test results of the ULB LSC show promising results for ultra-low background detection with liquid scintillation counting.

Optimal design and experimental validation of a simulated moving bed chromatography for continuous recovery of formic acid in a model mixture of three organic acids from Actinobacillus bacteria fermentation.

PubMed

Park, Chanhun; Nam, Hee-Geun; Lee, Ki Bong; Mun, Sungyong

2014-10-24

The economically-efficient separation of formic acid from acetic acid and succinic acid has been a key issue in the production of formic acid with the Actinobacillus bacteria fermentation. To address this issue, an optimal three-zone simulated moving bed (SMB) chromatography for continuous separation of formic acid from acetic acid and succinic acid was developed in this study. As a first step for this task, the adsorption isotherm and mass-transfer parameters of each organic acid on the qualified adsorbent (Amberchrom-CG300C) were determined through a series of multiple frontal experiments. The determined parameters were then used in optimizing the SMB process for the considered separation. During such optimization, the additional investigation for selecting a proper SMB port configuration, which could be more advantageous for attaining better process performances, was carried out between two possible configurations. It was found that if the properly selected port configuration was adopted in the SMB of interest, the throughout and the formic-acid product concentration could be increased by 82% and 181% respectively. Finally, the optimized SMB process based on the properly selected port configuration was tested experimentally using a self-assembled SMB unit with three zones. The SMB experimental results and the relevant computer simulation verified that the developed process in this study was successful in continuous recovery of formic acid from a ternary organic-acid mixture of interest with high throughput, high purity, high yield, and high product concentration. Copyright © 2014 Elsevier B.V. All rights reserved.

Optimal background matching camouflage.

PubMed

Michalis, Constantine; Scott-Samuel, Nicholas E; Gibson, David P; Cuthill, Innes C

2017-07-12

Background matching is the most familiar and widespread camouflage strategy: avoiding detection by having a similar colour and pattern to the background. Optimizing background matching is straightforward in a homogeneous environment, or when the habitat has very distinct sub-types and there is divergent selection leading to polymorphism. However, most backgrounds have continuous variation in colour and texture, so what is the best solution? Not all samples of the background are likely to be equally inconspicuous, and laboratory experiments on birds and humans support this view. Theory suggests that the most probable background sample (in the statistical sense), at the size of the prey, would, on average, be the most cryptic. We present an analysis, based on realistic assumptions about low-level vision, that estimates the distribution of background colours and visual textures, and predicts the best camouflage. We present data from a field experiment that tests and supports our predictions, using artificial moth-like targets under bird predation. Additionally, we present analogous data for humans, under tightly controlled viewing conditions, searching for targets on a computer screen. These data show that, in the absence of predator learning, the best single camouflage pattern for heterogeneous backgrounds is the most probable sample. © 2017 The Authors.

9 CFR 71.3 - Interstate movement of diseased animals and poultry generally prohibited.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., contagious bovine pleuropneumonia, highly pathogenic avian influenza, dourine, contagious equine metritis..., swine influenza, arthritis (simple lesions only), and shipping fever. (2) Cattle with slight unopened...

Background sources at PEP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lynch, H.; Schwitters, R.F.; Toner, W.T.

Important sources of background for PEP experiments are studied. Background particles originate from high-energy electrons and positrons which have been lost from stable orbits, ..gamma..-rays emitted by the primary beams through bremsstrahlung in the residual gas, and synchrotron radiation x-rays. The effect of these processes on the beam lifetime are calculated and estimates of background rates at the interaction region are given. Recommendations for the PEP design, aimed at minimizing background are presented. 7 figs., 4 tabs.

Backgrounds in Language.

ERIC Educational Resources Information Center

Maxwell, John C.; Long, Barbara K.

"Backgrounds in Language," a field-tested inservice course designed for use by groups of 15 or 25 language arts teachers, provides the subject matter background teachers need to make informed decisions about what curriculum materials to use in what way, at what time, and with which students. The course is comprised of eight 2-hour sessions,…

Simultaneous measurement of the viability, aggregation, and live and dead adherence of Streptococcus crista, Streptococcus mutans and Actinobacillus actinomycetemcomitans in human saliva in relation to indices of caries, dental plaque and periodontal disease.

PubMed

Rudney, J D; Staikov, R K

2002-05-01

Salivary proteins have multiple functions and many share similar functions, which may be why it has been difficult to relate variations in their concentrations to oral health and ecology. An alternative is to focus on variations in the major functions of saliva. An hydroxyapatite-coated microplate model has been developed that simultaneously measures saliva-promoted bacterial viability, bacterial aggregation, and live and dead bacterial adherence, while simulating oral temperature and shearing forces from swallowing. That model was applied to resting whole and stimulated parotid saliva from 149 individuals, using representative strains of Streptococcus crista, S. mutans, and Actinobacillus actinomycetemcomitans. Two major factors were defined by multivariate analysis (this was successful only for whole-saliva). One factor was correlated with aggregation, live adherence and dead adherence for all three strains; the other was correlated with total viability of all three strains. Participants were grouped <25th percentile and >75th percentile for each factor. Those groups were compared for clinical indices of oral health. Caries scores were significantly lower in those with high scores for aggregation-adherence, regardless of whether total viability scores were low or high. Live bacteria always predominated on surfaces when live and dead adherence scores were expressed as ratios. However, participants with high scores for aggregation-adherence showed significantly more dead adherent bacteria than those with low scores (these ratios were uncorrelated with total viability). This finding may indicate that extreme differences in the ability to kill bacteria on surfaces can influence caries risk.

Production of succinic acid from sugarcane molasses supplemented with a mixture of corn steep liquor powder and peanut meal as nitrogen sources by Actinobacillus succinogenes.

PubMed

Shen, N; Qin, Y; Wang, Q; Liao, S; Zhu, J; Zhu, Q; Mi, H; Adhikari, B; Wei, Y; Huang, R

2015-06-01

The potential of using corn steep liquor powder (CSLP), peanut meal (PM), soybean meal (SM), cotton meal (CM) and urea as the substitute of yeast extract (YE) as the nitrogen source was investigated for producing succinic acid (SA). Actinobacillus succinogenes GXAS137 was used as the fermenting bacterium and sugarcane molasses was used as the main substrate. None of these materials were able to produce SA as high as YE did. The CSLP could still be considered as a feasible and inexpensive alternate for YE as the yield of SA produced using CSLP was second only to the yield of SA obtained by YE. The use of CSLP-PM mixed formulation (CSLP to PM ratio = 2·6) as nitrogen source produced SA up to 59·2 g l(-1) with a productivity of 1·2 g l(-1) h(-1). A batch fermentation using a stirred bioreactor produced up to 60·7 g l(-1) of SA at the same formulation. Fed-batch fermentation that minimized the substrate inhibition produced 64·7 g l(-1) SA. These results suggest that sugarcane molasses supplemented with a mixture of CSLP and PM as the nitrogen source could be used to produce SA more economically using A. succinogenes. Significance and impact of the study: Succinic acid (SA) is commonly used as a platform chemical to produce a number of high value derivatives. Yeast extract (YE) is used as a nitrogen source to produce SA. The high cost of YE is currently the limiting factor for industrial production of SA. This study reports the use of a mixture of corn steep liquor powder (CSLP) and peanut meal (PM) as an inexpensive nitrogen source to substitute YE. The results showed that this CSLP-PM mixed formulation can be used as an effective and economic nitrogen source for the production of SA. © 2015 The Society for Applied Microbiology.

Visual signal detection in structured backgrounds. II. Effects of contrast gain control, background variations, and white noise

NASA Technical Reports Server (NTRS)

Eckstein, M. P.; Ahumada, A. J. Jr; Watson, A. B.

1997-01-01

Studies of visual detection of a signal superimposed on one of two identical backgrounds show performance degradation when the background has high contrast and is similar in spatial frequency and/or orientation to the signal. To account for this finding, models include a contrast gain control mechanism that pools activity across spatial frequency, orientation and space to inhibit (divisively) the response of the receptor sensitive to the signal. In tasks in which the observer has to detect a known signal added to one of M different backgrounds grounds due to added visual noise, the main sources of degradation are the stochastic noise in the image and the suboptimal visual processing. We investigate how these two sources of degradation (contrast gain control and variations in the background) interact in a task in which the signal is embedded in one of M locations in a complex spatially varying background (structured background). We use backgrounds extracted from patient digital medical images. To isolate effects of the fixed deterministic background (the contrast gain control) from the effects of the background variations, we conduct detection experiments with three different background conditions: (1) uniform background, (2) a repeated sample of structured background, and (3) different samples of structured background. Results show that human visual detection degrades from the uniform background condition to the repeated background condition and degrades even further in the different backgrounds condition. These results suggest that both the contrast gain control mechanism and the background random variations degrade human performance in detection of a signal in a complex, spatially varying background. A filter model and added white noise are used to generate estimates of sampling efficiencies, an equivalent internal noise, an equivalent contrast-gain-control-induced noise, and an equivalent noise due to the variations in the structured background.

Illuminating the Background: Topics in Cosmic Microwave Background Polarization Research

NASA Astrophysics Data System (ADS)

Miller, Nathan J.

The cosmic microwave background provides a wealth of information about the origin and history of the universe. The statistics of the anisotropy and the polarization of the cosmic microwave background, among other things, can tell us about the distribution of matter, the redshift of reionization, and the nature of the primordial uctuations. From the lensing of cosmic microwave background due to intervening matter, we can extract information about neutrinos and the equation of state of dark energy. A measurement of the large angular scale B-mode polarization has been called the "smoking gun" of in ation, a theory that describes a possible early rapid expansion of the universe. The focus of current experiments is to measure this B-mode polarization, while several experiments, such as POLARBEAR, are also looking to measure the lensing of the cosmic microwave background. This dissertation will discuss several different topics in cosmic microwave background polarization research. I will make predictions for future experiments and I will also show analysis for two current experiments, POLARBEAR and BICEP. I will show how beam systematics affect the measurement of cosmological parameters and how well we must limit these systematics in order to get unbiased constraints on cosmological parameters for future experiments. I will discuss a novel way of using the temperature-polarization cross correlation to constrain the amount of inflationary gravitational waves. Through Markov Chain Monte Carlo methods, I will determine how well future experiments will be able to constrain the neutrino masses and their degeneracy parameters. I will show results from current data analysis and calibration being done on the Cedar Flat deployment for the POLARBEAR experiment which is currently being constructed in the Atacama desert in Chile. Finally, I will analyze the claim of detection of cosmological birefringence in the BICEP data and show that there is reason to believe it is due to

Background Underground at WIPP

NASA Astrophysics Data System (ADS)

Esch, Ernst-Ingo; Hime, A.; Bowles, T. J.

2001-04-01

Recent interest to establish a dedicated underground laboratory in the United States prompted an experimental program at to quantify the enviromental backgrounds underground at the Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico. An outline of this program is provided along with recent experimental data on the cosmic ray muon flux at the 650 meter level of WIPP. The implications of the cosmic ray muon and fast neutron background at WIPP will be discussed in the context of new generation, low background experiments envisioned in the future.

A New Family of Capsule Polymerases Generates Teichoic Acid-Like Capsule Polymers in Gram-Negative Pathogens.

PubMed

Litschko, Christa; Oldrini, Davide; Budde, Insa; Berger, Monika; Meens, Jochen; Gerardy-Schahn, Rita; Berti, Francesco; Schubert, Mario; Fiebig, Timm

2018-05-29

Group 2 capsule polymers represent crucial virulence factors of Gram-negative pathogenic bacteria. They are synthesized by enzymes called capsule polymerases. In this report, we describe a new family of polymerases that combine glycosyltransferase and hexose- and polyol-phosphate transferase activity to generate complex poly(oligosaccharide phosphate) and poly(glycosylpolyol phosphate) polymers, the latter of which display similarity to wall teichoic acid (WTA), a cell wall component of Gram-positive bacteria. Using modeling and multiple-sequence alignment, we showed homology between the predicted polymerase domains and WTA type I biosynthesis enzymes, creating a link between Gram-negative and Gram-positive cell wall biosynthesis processes. The polymerases of the new family are highly abundant and found in a variety of capsule-expressing pathogens such as Neisseria meningitidis , Actinobacillus pleuropneumoniae , Haemophilus influenzae , Bibersteinia trehalosi , and Escherichia coli with both human and animal hosts. Five representative candidates were purified, their activities were confirmed using nuclear magnetic resonance (NMR) spectroscopy, and their predicted folds were validated by site-directed mutagenesis. IMPORTANCE Bacterial capsules play an important role in the interaction between a pathogen and the immune system of its host. During the last decade, capsule polymerases have become attractive tools for the production of capsule polymers applied as antigens in glycoconjugate vaccine formulations. Conventional production of glycoconjugate vaccines requires the cultivation of the pathogen and thus the highest biosafety standards, leading to tremendous costs. With regard to animal husbandry, where vaccines could avoid the extensive use of antibiotics, conventional production is not sufficiently cost-effective. In contrast, enzymatic synthesis of capsule polymers is pathogen-free and fast, offers high stereo- and regioselectivity, and works with high efficacy

Dilatonic parallelizable NS-NS backgrounds

NASA Astrophysics Data System (ADS)

Kawano, Teruhiko; Yamaguchi, Satoshi

2003-08-01

We complete the classification of parallelizable NS-NS backgrounds in type II supergravity by adding the dilatonic case to the result of Figueroa-O'Farrill on the non-dilatonic case. We also study the supersymmetry of these parallelizable backgrounds. It is shown that all the dilatonic parallelizable backgrounds have sixteen supersymmetries.

Unsupervised background-constrained tank segmentation of infrared images in complex background based on the Otsu method.

PubMed

Zhou, Yulong; Gao, Min; Fang, Dan; Zhang, Baoquan

2016-01-01

In an effort to implement fast and effective tank segmentation from infrared images in complex background, the threshold of the maximum between-class variance method (i.e., the Otsu method) is analyzed and the working mechanism of the Otsu method is discussed. Subsequently, a fast and effective method for tank segmentation from infrared images in complex background is proposed based on the Otsu method via constraining the complex background of the image. Considering the complexity of background, the original image is firstly divided into three classes of target region, middle background and lower background via maximizing the sum of their between-class variances. Then, the unsupervised background constraint is implemented based on the within-class variance of target region and hence the original image can be simplified. Finally, the Otsu method is applied to simplified image for threshold selection. Experimental results on a variety of tank infrared images (880 × 480 pixels) in complex background demonstrate that the proposed method enjoys better segmentation performance and even could be comparative with the manual segmentation in segmented results. In addition, its average running time is only 9.22 ms, implying the new method with good performance in real time processing.

Qualitative and quantitative impacts assessment of contagious bovine pleuropneumonia in Fulani pastoral herds of North-central Nigeria: The associated socio-cultural factors.

PubMed

Alhaji, N B; Babalobi, O O

2016-06-01

Contagious bovine pleuropneumonia is one of the most important trans-boundary disease affecting Fulani cattle herds of Nigeria and whose control is urgently needed. A Participatory Epidemiology approach and cross-sectional study were concurrently conducted to investigate qualitative and quantitative impacts of CBPP, respectively and associated socio-cultural factors that influenced exposure of Fulani nomadic pastoral communities to its risk in Niger State, North-central Nigeria between January and December 2013. A total of nine pastoral communities were purposively selected for qualitative impact assessment using Participatory Rural Appraisal tools, while 765 cattle randomly sampled from 125 purposively selected nomadic herds were analyzed using c-ELISA. Data on socio-cultural characteristics were collected using structured questionnaires administered on nomadic herd owners of the 125 selected herds. Kendall's Coefficient of Concordance W statistics and OpenEpi 2.3 were used for statistical analyses. Pastoralists' dependent factors associated with their socio-cultural activities were tested using Chisquare tests and likelihood backward logistic regressions. The mean proportional piles (relative qualitative impact) of CBPP was 12.6%, and nomads agreement on this impact was strong (W=0.6855) and statistically significant (P<0.001). This was validated by 16.2% (95% CI: 13.7, 19.0) sero-positive (quantitative impact). Highest sero-prevalence of 25.3% was observed in Northern agro-ecological zone, while lowest of 6.2% was in Eastern zone. Pastoralists in the age groups 51-60 and 61-70 years were more likely (OR 13.07; 95% CI: 3.21, 53.12 and OR 7.10; 95% CI: 1.77, 28.33, respectively) to have satisfactory information/awareness on CBPP and lowland transhumance pastoralists were more likely (OR 5.21; 95% CI: 2.01, 13.54) to have satisfactory information. Socio-cultural activities of extensive husbandry system was six times more likely (OR 5.79; 95% CI: 2.55, 13.13) to be

Low Background Counting at LBNL

DOE PAGES

Smith, A. R.; Thomas, K. J.; Norman, E. B.; ...

2015-03-24

The Low Background Facility (LBF) at Lawrence Berkeley National Laboratory in Berkeley, California provides low background gamma spectroscopy services to a wide array of experiments and projects. The analysis of samples takes place within two unique facilities; locally within a carefully-constructed, low background cave and remotely at an underground location that historically has operated underground in Oroville, CA, but has recently been relocated to the Sanford Underground Research Facility (SURF) in Lead, SD. These facilities provide a variety of gamma spectroscopy services to low background experiments primarily in the form of passive material screening for primordial radioisotopes (U, Th, K)more » or common cosmogenic/anthropogenic products, as well as active screening via Neutron Activation Analysis for specific applications. The LBF also provides hosting services for general R&D testing in low background environments on the surface or underground for background testing of detector systems or similar prototyping. A general overview of the facilities, services, and sensitivities is presented. Recent activities and upgrades will also be presented, such as the completion of a 3π anticoincidence shield at the surface station and environmental monitoring of Fukushima fallout. The LBF is open to any users for counting services or collaboration on a wide variety of experiments and projects.« less

Genetic background effects in Neuroligin-3 mutant mice: Minimal behavioral abnormalities on C57 background.

PubMed

Jaramillo, Thomas C; Escamilla, Christine Ochoa; Liu, Shunan; Peca, Lauren; Birnbaum, Shari G; Powell, Craig M

2018-02-01

Neuroligin-3 (NLGN3) is a postsynaptic cell adhesion protein that interacts with presynaptic ligands including neurexin-1 (NRXN1) [Ichtchenko et al., Journal of Biological Chemistry, 271, 2676-2682, 1996]. Mice harboring a mutation in the NLGN3 gene (NL3R451C) mimicking a mutation found in two brothers with autism spectrum disorder (ASD) were previously generated and behaviorally phenotyped for autism-related behaviors. In these NL3R451C mice generated and tested on a hybrid C57BL6J/129S2/SvPasCrl background, we observed enhanced spatial memory and reduced social interaction [Tabuchi et al., Science, 318, 71-76, 2007]. Curiously, an independently generated second line of mice harboring the same mutation on a C57BL6J background exhibited minimal aberrant behavior, thereby providing apparently discrepant results. To investigate the origin of the discrepancy, we previously replicated the original findings of Tabuchi et al. by studying the same NL3R451C mutation on a pure 129S2/SvPasCrl genetic background. Here we complete the behavioral characterization of the NL3R451C mutation on a pure C57BL6J genetic background to determine if background genetics play a role in the discrepant behavioral outcomes involving NL3R451C mice. NL3R451C mutant mice on a pure C57BL6J background did not display spatial memory enhancements or social interaction deficits. We only observed a decreased startle response and mildly increased locomotor activity in these mice suggesting that background genetics influences behavioral outcomes involving the NL3R451C mutation. Autism Res 2018, 11: 234-244. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. Behavioral symptoms of autism can be highly variable, even in cases that involve identical genetic mutations. Previous studies in mice with a mutation of the Neuroligin-3 gene showed enhanced learning and social deficits. We replicated these findings on the same and different genetic backgrounds. In this study, however, the

Background Light Bluer Than Expected

NASA Image and Video Library

2014-11-06

This plot shows data from the Cosmic Infrared Background Experiment, or CIBER, rockets launched in 2010 and 2012. The experiment measures a diffuse glow of infrared light in the sky, known as the cosmic infrared background.

The background in the $$0\

DOE PAGES

Agostini, M.; Allardt, M.; Andreotti, E.; ...

2014-04-04

The GERmanium Detector Array (Gerda) experiment at the Gran Sasso underground laboratory (LNGS) of INFN is searching for neutrinoless double beta (0νββ) decay of 76 Ge. The signature of the signal is a monoenergetic peak at 2039 keV, the Q ββ value of the decay. To avoid bias in the signal search, the present analysis does not consider all those events, that fall in a 40 keV wide region centered around Q ββ. The main parameters needed for the 0νββ analysis are described. A background model was developed to describe the observed energy spectrum. The model contains severalmore » contributions, that are expected on the basis of material screening or that are established by the observation of characteristic structures in the energy spectrum. The model predicts a flat energy spectrum for the blinding window around Qββ with a background index ranging from 17.6 to 23.8 × 10 -3 cts/(keV kg yr). A part of the data not considered before has been used to test if the predictions of the background model are consistent. The observed number of events in this energy region is consistent with the background model. The background at Q ββ is dominated by close sources, mainly due to 42 K, 214 Bi, 228 60 Co and α emitting isotopes from the 226 Ra decay chain. The individual fractions depend on the assumed locations of the contaminants. It is shown, that after removal of the known γ peaks, the energy spectrum can be fitted in an energy range of 200 keV around Q ββ with a constant background. This gives a background index consistent with the full model and uncertainties of the same size.« less

A Flexible Cosmic Ultraviolet Background Model

NASA Astrophysics Data System (ADS)

McQuinn, Matthew

2016-10-01

HST studies of the IGM, of the CGM, and of reionization-era galaxies are all aided by ionizing background models, which are a critical input in modeling the ionization state of diffuse, 10^4 K gas. The ionization state in turn enables the determination of densities and sizes of absorbing clouds and, when applied to the Ly-a forest, the global ionizing emissivity of sources. Unfortunately, studies that use these background models have no way of gauging the amount of uncertainty in the adopted model other than to recompute their results using previous background models with outdated observational inputs. As of yet there has been no systematic study of uncertainties in the background model and there unfortunately is no publicly available ultraviolet background code. A public code would enable users to update the calculation with the latest observational constraints, and it would allow users to experiment with varying the background model's assumptions regarding emissions and absorptions. We propose to develop a publicly available ionizing background code and, as an initial application, quantify the level of uncertainty in the ionizing background spectrum across cosmic time. As the background model improves, so does our understanding of (1) the sources that dominate ionizing emissions across cosmic time and (2) the properties of diffuse gas in the circumgalactic medium, the WHIM, and the Ly-a forest. HST is the primary telescope for studying both the highest redshift galaxies and low-redshift diffuse gas. The proposed program would benefit HST studies of the Universe at z 0 all the way up to z = 10, including of high-z galaxies observed in the HST Frontier Fields.

47 CFR 215.1 - Background.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

47 CFR 215.1 - Background.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Background. 215.1 Section 215.1 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL FEDERAL GOVERNMENT FOCAL POINT FOR ELECTROMAGNETIC PULSE (EMP) INFORMATION § 215.1 Background. (a) The nuclear electromagnetic...

40 CFR 11.2 - Background.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Background. 11.2 Section 11.2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL SECURITY CLASSIFICATION REGULATIONS PURSUANT TO EXECUTIVE ORDER 11652 § 11.2 Background. While the Environmental Protection Agency does not...

Extragalactic background light measurements and applications.

PubMed

Cooray, Asantha

2016-03-01

This review covers the measurements related to the extragalactic background light intensity from γ-rays to radio in the electromagnetic spectrum over 20 decades in wavelength. The cosmic microwave background (CMB) remains the best measured spectrum with an accuracy better than 1%. The measurements related to the cosmic optical background (COB), centred at 1 μm, are impacted by the large zodiacal light associated with interplanetary dust in the inner Solar System. The best measurements of COB come from an indirect technique involving γ-ray spectra of bright blazars with an absorption feature resulting from pair-production off of COB photons. The cosmic infrared background (CIB) peaking at around 100 μm established an energetically important background with an intensity comparable to the optical background. This discovery paved the way for large aperture far-infrared and sub-millimetre observations resulting in the discovery of dusty, starbursting galaxies. Their role in galaxy formation and evolution remains an active area of research in modern-day astrophysics. The extreme UV (EUV) background remains mostly unexplored and will be a challenge to measure due to the high Galactic background and absorption of extragalactic photons by the intergalactic medium at these EUV/soft X-ray energies. We also summarize our understanding of the spatial anisotropies and angular power spectra of intensity fluctuations. We motivate a precise direct measurement of the COB between 0.1 and 5 μm using a small aperture telescope observing either from the outer Solar System, at distances of 5 AU or more, or out of the ecliptic plane. Other future applications include improving our understanding of the background at TeV energies and spectral distortions of CMB and CIB.

Extragalactic background light measurements and applications

PubMed Central

Cooray, Asantha

2016-01-01

This review covers the measurements related to the extragalactic background light intensity from γ-rays to radio in the electromagnetic spectrum over 20 decades in wavelength. The cosmic microwave background (CMB) remains the best measured spectrum with an accuracy better than 1%. The measurements related to the cosmic optical background (COB), centred at 1 μm, are impacted by the large zodiacal light associated with interplanetary dust in the inner Solar System. The best measurements of COB come from an indirect technique involving γ-ray spectra of bright blazars with an absorption feature resulting from pair-production off of COB photons. The cosmic infrared background (CIB) peaking at around 100 μm established an energetically important background with an intensity comparable to the optical background. This discovery paved the way for large aperture far-infrared and sub-millimetre observations resulting in the discovery of dusty, starbursting galaxies. Their role in galaxy formation and evolution remains an active area of research in modern-day astrophysics. The extreme UV (EUV) background remains mostly unexplored and will be a challenge to measure due to the high Galactic background and absorption of extragalactic photons by the intergalactic medium at these EUV/soft X-ray energies. We also summarize our understanding of the spatial anisotropies and angular power spectra of intensity fluctuations. We motivate a precise direct measurement of the COB between 0.1 and 5 μm using a small aperture telescope observing either from the outer Solar System, at distances of 5 AU or more, or out of the ecliptic plane. Other future applications include improving our understanding of the background at TeV energies and spectral distortions of CMB and CIB. PMID:27069645

Association of Radon Background and Total Background Ionizing Radiation with Alzheimer's Disease Deaths in U.S. States.

PubMed

Lehrer, Steven; Rheinstein, Peter H; Rosenzweig, Kenneth E

2017-01-01

Exposure of the brain to ionizing radiation might promote the development of Alzheimer's disease (AD). Analysis of AD death rates versus radon background radiation and total background radiation in U.S. states. Total background, radon background, cosmic and terrestrial background radiation measurements are from Assessment of Variations in Radiation Exposure in the United States and Report No. 160 - Ionizing Radiation Exposure of the Population of the United States. 2013 AD death rates by U.S. state are from the Alzheimer's Association. Radon background ionizing radiation was significantly correlated with AD death rate in 50 states and the District of Columbia (r = 0.467, p = 0.001). Total background ionizing radiation was also significantly correlated with AD death rate in 50 states and the District of Columbia (r = 0.452, p = 0.001). Multivariate linear regression weighted by state population demonstrated that AD death rate was significantly correlated with radon background (β= 0.169, p < 0.001), age (β= 0.231, p < 0.001), hypertension (β= 0.155, p < 0.001), and diabetes (β= 0.353, p < 0.001). Our findings, like other studies, suggest that ionizing radiation is a risk factor for AD. Intranasal inhalation of radon gas could subject the rhinencephalon and hippocampus to damaging radiation that initiates AD. The damage would accumulate over time, causing age to be a powerful risk factor.

47 CFR 201.0 - Background.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 5 2013-10-01 2013-10-01 false Background. 201.0 Section 201.0 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EXECUTIVE POLICY § 201.0 Background. National policy with respect to the conservation, allocation and use of the Nation's...

47 CFR 201.0 - Background.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Background. 201.0 Section 201.0 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EXECUTIVE POLICY § 201.0 Background. National policy with respect to the conservation, allocation and use of the Nation's...

47 CFR 201.0 - Background.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Background. 201.0 Section 201.0 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EXECUTIVE POLICY § 201.0 Background. National policy with respect to the conservation, allocation and use of the Nation's...

47 CFR 201.0 - Background.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 5 2014-10-01 2014-10-01 false Background. 201.0 Section 201.0 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EXECUTIVE POLICY § 201.0 Background. National policy with respect to the conservation, allocation and use of the Nation's...

47 CFR 201.0 - Background.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Background. 201.0 Section 201.0 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL EXECUTIVE POLICY § 201.0 Background. National policy with respect to the conservation, allocation and use of the Nation's...

28 CFR 23.2 - Background.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 28 Judicial Administration 1 2011-07-01 2011-07-01 false Background. 23.2 Section 23.2 Judicial Administration DEPARTMENT OF JUSTICE CRIMINAL INTELLIGENCE SYSTEMS OPERATING POLICIES § 23.2 Background. It is... of intelligence data necessary to support control of serious criminal activity may represent...

28 CFR 23.2 - Background.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 28 Judicial Administration 1 2014-07-01 2014-07-01 false Background. 23.2 Section 23.2 Judicial Administration DEPARTMENT OF JUSTICE CRIMINAL INTELLIGENCE SYSTEMS OPERATING POLICIES § 23.2 Background. It is... of intelligence data necessary to support control of serious criminal activity may represent...

28 CFR 23.2 - Background.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 28 Judicial Administration 1 2013-07-01 2013-07-01 false Background. 23.2 Section 23.2 Judicial Administration DEPARTMENT OF JUSTICE CRIMINAL INTELLIGENCE SYSTEMS OPERATING POLICIES § 23.2 Background. It is... of intelligence data necessary to support control of serious criminal activity may represent...

28 CFR 23.2 - Background.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Background. 23.2 Section 23.2 Judicial Administration DEPARTMENT OF JUSTICE CRIMINAL INTELLIGENCE SYSTEMS OPERATING POLICIES § 23.2 Background. It is... of intelligence data necessary to support control of serious criminal activity may represent...

28 CFR 23.2 - Background.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 28 Judicial Administration 1 2012-07-01 2012-07-01 false Background. 23.2 Section 23.2 Judicial Administration DEPARTMENT OF JUSTICE CRIMINAL INTELLIGENCE SYSTEMS OPERATING POLICIES § 23.2 Background. It is... of intelligence data necessary to support control of serious criminal activity may represent...

47 CFR 32.1 - Background.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 2 2014-10-01 2014-10-01 false Background. 32.1 Section 32.1 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Preface § 32.1 Background. The revised Uniform System of Accounts (USOA) is a historical...

47 CFR 32.1 - Background.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 2 2013-10-01 2013-10-01 false Background. 32.1 Section 32.1 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Preface § 32.1 Background. The revised Uniform System of Accounts (USOA) is a historical...

47 CFR 32.1 - Background.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 2 2011-10-01 2011-10-01 false Background. 32.1 Section 32.1 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Preface § 32.1 Background. The revised Uniform System of Accounts (USOA) is a historical...

Spectral characterization of natural backgrounds

NASA Astrophysics Data System (ADS)

Winkelmann, Max

2017-10-01

As the distribution and use of hyperspectral sensors is constantly increasing, the exploitation of spectral features is a threat for camouflaged objects. To improve camouflage materials at first the spectral behavior of backgrounds has to be known to adjust and optimize the spectral reflectance of camouflage materials. In an international effort, the NATO CSO working group SCI-295 "Development of Methods for Measurements and Evaluation of Natural Background EO Signatures" is developing a method how this characterization of backgrounds has to be done. It is obvious that the spectral characterization of a background will be quite an effort. To compare and exchange data internationally the measurements will have to be done in a similar way. To test and further improve this method an international field trial has been performed in Storkow, Germany. In the following we present first impressions and lessons learned from this field campaign and describe the data that has been measured.

9 CFR 53.2 - Determination of existence of disease; agreements with States.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Determination of existence of disease... SERVICE, DEPARTMENT OF AGRICULTURE COOPERATIVE CONTROL AND ERADICATION OF LIVESTOCK OR POULTRY DISEASES FOOT-AND-MOUTH DISEASE, PLEUROPNEUMONIA, RINDERPEST, AND CERTAIN OTHER COMMUNICABLE DISEASES OF...

9 CFR 53.2 - Determination of existence of disease; agreements with States.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Determination of existence of disease... SERVICE, DEPARTMENT OF AGRICULTURE COOPERATIVE CONTROL AND ERADICATION OF LIVESTOCK OR POULTRY DISEASES FOOT-AND-MOUTH DISEASE, PLEUROPNEUMONIA, RINDERPEST, AND CERTAIN OTHER COMMUNICABLE DISEASES OF...

9 CFR 53.2 - Determination of existence of disease; agreements with States.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Determination of existence of disease... SERVICE, DEPARTMENT OF AGRICULTURE COOPERATIVE CONTROL AND ERADICATION OF LIVESTOCK OR POULTRY DISEASES FOOT-AND-MOUTH DISEASE, PLEUROPNEUMONIA, RINDERPEST, AND CERTAIN OTHER COMMUNICABLE DISEASES OF...

9 CFR 53.2 - Determination of existence of disease; agreements with States.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Determination of existence of disease... SERVICE, DEPARTMENT OF AGRICULTURE COOPERATIVE CONTROL AND ERADICATION OF LIVESTOCK OR POULTRY DISEASES FOOT-AND-MOUTH DISEASE, PLEUROPNEUMONIA, RINDERPEST, AND CERTAIN OTHER COMMUNICABLE DISEASES OF...

9 CFR 53.2 - Determination of existence of disease; agreements with States.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Determination of existence of disease... SERVICE, DEPARTMENT OF AGRICULTURE COOPERATIVE CONTROL AND ERADICATION OF LIVESTOCK OR POULTRY DISEASES FOOT-AND-MOUTH DISEASE, PLEUROPNEUMONIA, RINDERPEST, AND CERTAIN OTHER COMMUNICABLE DISEASES OF...

Mannheimia haemolytica A1-induced fibrinosuppurative meningoencephalitis in a naturally-infected Holstein-Friesian calf

USDA-ARS?s Scientific Manuscript database

Mannheimia haemolytica is an opportunistic bacterium that is widely recognized among the bovine respiratory disease complex as the predominant pathogen associated with pleuropneumonia in cattle. Among the characterized M. haemolytica serotypes, A1 is the major cause of severe pulmonary lesions in ca...

The National Bio- and Agro-Defense Facility: Issues for Congress

DTIC Science & Technology

2008-05-19

classical swine fever , African swine fever , Rift Valley fever , Nipah virus, Hendra virus, contagious bovine pleuropneumonia, and Japanese...Preparedness, by Jim Monke. 2 Examples include influenza, plague, West Nile Virus, and Rift Valley Fever . 3 These diseases are sometimes referred to as foreign

32 CFR 1292.3 - Background.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 6 2010-07-01 2010-07-01 false Background. 1292.3 Section 1292.3 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS SECURITY OF DLA ACTIVITIES AND RESOURCES § 1292.3 Background. Section 21 of the Internal Security Act of 1950...

14 CFR 1214.302 - Background.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Background. 1214.302 Section 1214.302 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT Payload Specialists for Space Transportation System (STS) Missions § 1214.302 Background. (a) The Space Transportation System (STS) has been...

14 CFR 1214.302 - Background.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Background. 1214.302 Section 1214.302 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT Payload Specialists for Space Transportation System (STS) Missions § 1214.302 Background. (a) The Space Transportation System (STS) has been...

14 CFR 1214.302 - Background.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Background. 1214.302 Section 1214.302 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT Payload Specialists for Space Transportation System (STS) Missions § 1214.302 Background. (a) The Space Transportation System (STS) has been...

14 CFR 1214.302 - Background.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Background. 1214.302 Section 1214.302 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT Payload Specialists for Space Transportation System (STS) Missions § 1214.302 Background. (a) The Space Transportation System (STS) has been...

32 CFR 1292.3 - Background.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 32 National Defense 6 2012-07-01 2012-07-01 false Background. 1292.3 Section 1292.3 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS SECURITY OF DLA ACTIVITIES AND RESOURCES § 1292.3 Background. Section 21 of the Internal Security Act of 1950...

32 CFR 1292.3 - Background.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 6 2011-07-01 2011-07-01 false Background. 1292.3 Section 1292.3 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS SECURITY OF DLA ACTIVITIES AND RESOURCES § 1292.3 Background. Section 21 of the Internal Security Act of 1950...

32 CFR 1292.3 - Background.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 6 2013-07-01 2013-07-01 false Background. 1292.3 Section 1292.3 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS SECURITY OF DLA ACTIVITIES AND RESOURCES § 1292.3 Background. Section 21 of the Internal Security Act of 1950...

32 CFR 1292.3 - Background.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 32 National Defense 6 2014-07-01 2014-07-01 false Background. 1292.3 Section 1292.3 National Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS SECURITY OF DLA ACTIVITIES AND RESOURCES § 1292.3 Background. Section 21 of the Internal Security Act of 1950...

32 CFR 3.2 - Background.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 1 2010-07-01 2010-07-01 false Background. 3.2 Section 3.2 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE ACQUISITION TRANSACTIONS OTHER THAN CONTRACTS, GRANTS, OR COOPERATIVE AGREEMENTS FOR PROTOTYPE PROJECTS § 3.2 Background. “Other transactions” is the...

32 CFR 763.3 - Background.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 5 2010-07-01 2010-07-01 false Background. 763.3 Section 763.3 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY ISLANDS UNDER NAVY JURISDICTION RULES GOVERNING PUBLIC ACCESS Entry Regulations for Kaho'olawe Island, Hawaii § 763.3 Background. (a) Kaho'olawe Island...

32 CFR 735.2 - Background.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 5 2011-07-01 2011-07-01 false Background. 735.2 Section 735.2 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL REPORTING BIRTHS AND DEATHS IN COOPERATION WITH OTHER AGENCIES § 735.2 Background. For Armed Forces members and their dependents on duty overseas...

32 CFR 735.2 - Background.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 5 2010-07-01 2010-07-01 false Background. 735.2 Section 735.2 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL REPORTING BIRTHS AND DEATHS IN COOPERATION WITH OTHER AGENCIES § 735.2 Background. For Armed Forces members and their dependents on duty overseas...

Aircraft and background noise annoyance effects

NASA Technical Reports Server (NTRS)

Willshire, K. F.

1984-01-01

To investigate annoyance of multiple noise sources, two experiments were conducted. The first experiment, which used 48 subjects, was designed to establish annoyance-noise level functions for three community noise sources presented individually: jet aircraft flyovers, air conditioner, and traffic. The second experiment, which used 216 subjects, investigated the effects of background noise on aircraft annoyance as a function of noise level and spectrum shape; and the differences between overall, aircraft, and background noise annoyance. In both experiments, rated annoyance was the dependent measure. Results indicate that the slope of the linear relationship between annoyance and noise level for traffic is significantly different from that of flyover and air conditioner noise and that further research was justified to determine the influence of the two background noises on overall, aircraft, and background noise annoyance (e.g., experiment two). In experiment two, total noise exposure, signal-to-noise ratio, and background source type were found to have effects on all three types of annoyance. Thus, both signal-to-noise ratio, and the background source must be considered when trying to determine community response to combined noise sources.

Characterization of phytase enzymes as feed additive for poultry and feed

NASA Astrophysics Data System (ADS)

Lamid, M.; Al-Arif, A.; Asmarani, O.; Warsito, S. H.

2018-04-01

One of the obstacles to utilizing rice bran as feed is the presence of antinutrition in the form of phytic acid which binds in minerals to form complex compounds with P, Mg, Mn, Fe, Zn, Ca. Phytic acid and its salts are the main forms of P, Mg, Mn, Fe, Zn, Ca deposits contained in cereals, legume and grains, about 60-90% of total minerals P, Mg, Mn, Fe, Zn, Ca in the form of phytic acid or phytate salts. Phytate is one of the enzymes belonging to the phosphatase group capable of hydrolyzing phytate compounds of myo-inositol (1,2,3,4,5,6) hexsa phosphatase into myo-inositol and organic phosphat. The aim of this study was to obtain characterization of phytase enzymes from isolate Actinobacillus sp., Bacillus pumilus, Bacillus vallimortis and IBR-1. Determination of phytase activity and the absorbance was measured using a UV-Vis spectrophotometer at a wavelength of 392 nm. The result of Actinobacillus sp, Bacillus pumilus, Bacillus vallimortis, IBR-1 each having optimum temperature were 50°C, 40°C, 45°C, 45°C, and optimum pH were 4, 4, 5.5. Bacteria especially Actinobacillus sp, Bacillus pumilus, Bacillus vallimortis, IBR-1 are proven capable of producing the high enough phytase enzymes required for mineral availability for livestock and fish.

32 CFR 732.1 - Background.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 5 2010-07-01 2010-07-01 false Background. 732.1 Section 732.1 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL NONNAVAL MEDICAL AND DENTAL CARE General § 732.1 Background. When a U.S. Navy or Marine Corps member or a Canadian Navy or Marine Corps member...

32 CFR 732.1 - Background.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 5 2013-07-01 2013-07-01 false Background. 732.1 Section 732.1 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL NONNAVAL MEDICAL AND DENTAL CARE General § 732.1 Background. When a U.S. Navy or Marine Corps member or a Canadian Navy or Marine Corps member...

32 CFR 732.1 - Background.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 32 National Defense 5 2014-07-01 2014-07-01 false Background. 732.1 Section 732.1 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL NONNAVAL MEDICAL AND DENTAL CARE General § 732.1 Background. When a U.S. Navy or Marine Corps member or a Canadian Navy or Marine Corps member...

32 CFR 732.1 - Background.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 5 2011-07-01 2011-07-01 false Background. 732.1 Section 732.1 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL NONNAVAL MEDICAL AND DENTAL CARE General § 732.1 Background. When a U.S. Navy or Marine Corps member or a Canadian Navy or Marine Corps member...

32 CFR 732.1 - Background.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 32 National Defense 5 2012-07-01 2012-07-01 false Background. 732.1 Section 732.1 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL NONNAVAL MEDICAL AND DENTAL CARE General § 732.1 Background. When a U.S. Navy or Marine Corps member or a Canadian Navy or Marine Corps member...

12 CFR 408.1 - Background.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Background. 408.1 Section 408.1 Banks and Banking EXPORT-IMPORT BANK OF THE UNITED STATES PROCEDURES FOR COMPLIANCE WITH THE NATIONAL ENVIRONMENTAL POLICY ACT General § 408.1 Background. (a) The National Environmental Policy Act (NEPA) of 1969 (42 U.S.C...

Background of SAM atom-fraction profiles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ernst, Frank

Atom-fraction profiles acquired by SAM (scanning Auger microprobe) have important applications, e.g. in the context of alloy surface engineering by infusion of carbon or nitrogen through the alloy surface. However, such profiles often exhibit an artifact in form of a background with a level that anti-correlates with the local atom fraction. This article presents a theory explaining this phenomenon as a consequence of the way in which random noise in the spectrum propagates into the discretized differentiated spectrum that is used for quantification. The resulting model of “energy channel statistics” leads to a useful semi-quantitative background reduction procedure, which ismore » validated by applying it to simulated data. Subsequently, the procedure is applied to an example of experimental SAM data. The analysis leads to conclusions regarding optimum experimental acquisition conditions. The proposed method of background reduction is based on general principles and should be useful for a broad variety of applications. - Highlights: • Atom-fraction–depth profiles of carbon measured by scanning Auger microprobe • Strong background, varies with local carbon concentration. • Needs correction e.g. for quantitative comparison with simulations • Quantitative theory explains background. • Provides background removal strategy and practical advice for acquisition.« less

The National Bio- and Agro-Defense Facility: Issues for Congress

DTIC Science & Technology

2007-09-04

example, research on Nipah virus must be performed in a BSL-4 laboratory. diagnostic capabilities for foreign animal and zoonotic diseases.”4 The...fever, African swine fever, Rift Valley fever, Nipah virus, Hendra virus, contagious bovine pleuropneumonia, and Japanese encephalitis.9 The DHS plans

The National Bio- and Agro-Defense Facility: Issues for Congress

DTIC Science & Technology

2007-11-15

and mouth disease (FMD), classical swine fever , African swine fever , Rift Valley fever , Nipah virus, Hendra virus, contagious bovine pleuropneumonia...Preparedness, by Jim Monke. 2 Examples include influenza, plague, West Nile Virus, and Rift Valley Fever . 3 These diseases are sometimes referred to as

Anti-microbial Activity of Tulsi {Ocimum Sanctum (Linn.)} Extract on a Periodontal Pathogen in Human Dental Plaque: An Invitro Study

PubMed Central

Devaraj, C.G.; Agarwal, Payal

2016-01-01

Introduction Tulsi is a popular healing herb in Ayurvedic medicine. It is widely used in the treatment of several systemic diseases because of its anti-microbial property. However, studies documenting the effect of Tulsi on oral disease causing organisms are rare. Hence, an attempt was made to determine the effect of Tulsi on a periodontal microorganism in human dental plaque. Aim To determine if Ocimum sanctum (Linn.) has an anti-microbial activity (Minimum Inhibitory Concentration and zone of inhibition) against Actinobacillus actinomycetemcomitans in human dental plaque and to compare the antimicrobial activity of Ocimum sanctum(Linn.) extract with 0.2% chlorhexidine as the positive control and dimethyl sulfoxide as the negative control. Materials and Methods A lab based invitro experimental study design was adopted. Ethanolic extract of Ocimum sanctum (Linn.) was prepared by the cold extraction method. The extract was diluted with an inert solvent, dimethyl sulfoxide, to obtain ten different concentrations (1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%) of extract. Plaque sample was collected from 05 subjects diagnosed with periodontal disease. Isolation of Actinobacillus actinomycetemcomitans from plaque samples was done using Tryptic Soy Serum Bacitracin Vancomycin agar (TSBV) medium. Identification of Actinobacillus actinomycetemcomitans was done based on cultural, microscopic, biochemical characterization and multiple drug resistance patterns. Anti-microbial activity of Ocimum sanctum (Linn.) extract was tested by agar well-diffusion method against 0.2% chlorhexidine as a positive control and dimethyl sulfoxide as a negative control. The zone of inhibition was measured in millimeters using Vernier callipers. Results At the 6% w/v concentration of Ocimum sanctum (Linn.) extract, a zone of inhibition of 22 mm was obtained. This was the widest zone of inhibition observed among all the 10 different concentrations tested. The zone of inhibition for positive control

Anti-microbial Activity of Tulsi {Ocimum Sanctum (Linn.)} Extract on a Periodontal Pathogen in Human Dental Plaque: An Invitro Study.

PubMed

Eswar, Pranati; Devaraj, C G; Agarwal, Payal

2016-03-01

Tulsi is a popular healing herb in Ayurvedic medicine. It is widely used in the treatment of several systemic diseases because of its anti-microbial property. However, studies documenting the effect of Tulsi on oral disease causing organisms are rare. Hence, an attempt was made to determine the effect of Tulsi on a periodontal microorganism in human dental plaque. To determine if Ocimum sanctum (Linn.) has an anti-microbial activity (Minimum Inhibitory Concentration and zone of inhibition) against Actinobacillus actinomycetemcomitans in human dental plaque and to compare the antimicrobial activity of Ocimum sanctum(Linn.) extract with 0.2% chlorhexidine as the positive control and dimethyl sulfoxide as the negative control. A lab based invitro experimental study design was adopted. Ethanolic extract of Ocimum sanctum (Linn.) was prepared by the cold extraction method. The extract was diluted with an inert solvent, dimethyl sulfoxide, to obtain ten different concentrations (1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%) of extract. Plaque sample was collected from 05 subjects diagnosed with periodontal disease. Isolation of Actinobacillus actinomycetemcomitans from plaque samples was done using Tryptic Soy Serum Bacitracin Vancomycin agar (TSBV) medium. Identification of Actinobacillus actinomycetemcomitans was done based on cultural, microscopic, biochemical characterization and multiple drug resistance patterns. Anti-microbial activity of Ocimum sanctum (Linn.) extract was tested by agar well-diffusion method against 0.2% chlorhexidine as a positive control and dimethyl sulfoxide as a negative control. The zone of inhibition was measured in millimeters using Vernier callipers. At the 6% w/v concentration of Ocimum sanctum (Linn.) extract, a zone of inhibition of 22 mm was obtained. This was the widest zone of inhibition observed among all the 10 different concentrations tested. The zone of inhibition for positive control was 25mm and no zone of inhibition was observed

The background in the experiment Gerda

NASA Astrophysics Data System (ADS)

Agostini, M.; Allardt, M.; Andreotti, E.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Barnabé Heider, M.; Barros, N.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Brudanin, V.; Brugnera, R.; Budjáš, D.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; Cossavella, F.; Demidova, E. V.; Domula, A.; Egorov, V.; Falkenstein, R.; Ferella, A.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gotti, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Guthikonda, K. K.; Hampel, W.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Ioannucci, L.; Csáthy, J. Janicskó; Jochum, J.; Junker, M.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Klimenko, A.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Liu, X.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Machado, A. A.; Majorovits, B.; Maneschg, W.; Nemchenok, I.; Nisi, S.; O'Shaughnessy, C.; Palioselitis, D.; Pandola, L.; Pelczar, K.; Pessina, G.; Pullia, A.; Riboldi, S.; Sada, C.; Salathe, M.; Schmitt, C.; Schreiner, J.; Schulz, O.; Schwingenheuer, B.; Schönert, S.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Strecker, H.; Tarka, M.; Ur, C. A.; Vasenko, A. A.; Volynets, O.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wojcik, M.; Yanovich, E.; Zavarise, P.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

2014-04-01

The GERmanium Detector Array ( Gerda) experiment at the Gran Sasso underground laboratory (LNGS) of INFN is searching for neutrinoless double beta () decay of Ge. The signature of the signal is a monoenergetic peak at 2039 keV, the value of the decay. To avoid bias in the signal search, the present analysis does not consider all those events, that fall in a 40 keV wide region centered around . The main parameters needed for the analysis are described. A background model was developed to describe the observed energy spectrum. The model contains several contributions, that are expected on the basis of material screening or that are established by the observation of characteristic structures in the energy spectrum. The model predicts a flat energy spectrum for the blinding window around with a background index ranging from 17.6 to 23.8 cts/(keV kg yr). A part of the data not considered before has been used to test if the predictions of the background model are consistent. The observed number of events in this energy region is consistent with the background model. The background at is dominated by close sources, mainly due to K, Bi, Th, Co and emitting isotopes from the Ra decay chain. The individual fractions depend on the assumed locations of the contaminants. It is shown, that after removal of the known peaks, the energy spectrum can be fitted in an energy range of 200 keV around with a constant background. This gives a background index consistent with the full model and uncertainties of the same size.

The cosmic microwave background

NASA Technical Reports Server (NTRS)

Silk, Joseph

1991-01-01

Recent limits on spectral distortions and angular anisotropies in the cosmic microwave background are reviewed. The various backgrounds are described, and the theoretical implications are assessed. Constraints on inflationary cosmology dominated by cold dark matter (CDM) and on open cosmological models dominated by baryonic dark matter (BDM), with, respectively, primordial random phase scale-invariant curvature fluctuations or non-gaussian isocurvature fluctuations are described. More exotic theories are addressed, and I conclude with the 'bottom line': what theorists expect experimentalists to be measuring within the next two to three years without having to abandon their most cherished theories.

Characterizing the Background Corona with SDO/AIA

NASA Technical Reports Server (NTRS)

Napier, Kate; Alexander, Caroline; Winebarger, Amy

2014-01-01

Characterizing the nature of the solar coronal background would enable scientists to more accurately determine plasma parameters, and may lead to a better understanding of the coronal heating problem. Because scientists study the 3D structure of the Sun in 2D, any line-of-sight includes both foreground and background material, and thus, the issue of background subtraction arises. By investigating the intensity values in and around an active region, using multiple wavelengths collected from the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) over an eight-hour period, this project aims to characterize the background as smooth or structured. Different methods were employed to measure the true coronal background and create minimum intensity images. These were then investigated for the presence of structure. The background images created were found to contain long-lived structures, including coronal loops, that were still present in all of the wavelengths, 131, 171, 193, 211, and 335 A. The intensity profiles across the active region indicate that the background is much more structured than previously thought.

Cosmic Background Explorer (COBE) press kit

NASA Technical Reports Server (NTRS)

1989-01-01

COBE, the Cosmic Background Explorer spacecraft, and its mission are described. COBE was designed to study the origin and dynamics of the universe including the theory that the universe began with a cataclysmic explosion referred to as the Big Bang. To this end, earth's cosmic background - the infrared radiation that bombards earth from every direction - will be measured by three sophisticated instruments: the Differential Microwave Radiometer (DMR), the Far Infrared Absolute Spectrophotometer (FIRAS), and the Diffuse Infrared Background Experiment (DIRBE).

Characterization and Prediction of the SPI Background

NASA Technical Reports Server (NTRS)

Teegarden, B. J.; Jean, P.; Knodlseder, J.; Skinner, G. K.; Weidenspointer, G.

2003-01-01

The INTEGRAL Spectrometer, like most gamma-ray instruments, is background dominated. Signal-to-background ratios of a few percent are typical. The background is primarily due to interactions of cosmic rays in the instrument and spacecraft. It characteristically varies by +/- 5% on time scales of days. This variation is caused mainly by fluctuations in the interplanetary magnetic field that modulates the cosmic ray intensity. To achieve the maximum performance from SPI it is essential to have a high quality model of this background that can predict its value to a fraction of a percent. In this poster we characterize the background and its variability, explore various models, and evaluate the accuracy of their predictions.

Expected background in the LZ experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kudryavtsev, Vitaly A.

2015-08-17

The LZ experiment, featuring a 7-tonne active liquid xenon target, is aimed at achieving unprecedented sensitivity to WIMPs with the background expected to be dominated by astrophysical neutrinos. To reach this goal, extensive simulations are carried out to accurately calculate the electron recoil and nuclear recoil rates in the detector. Both internal (from target material) and external (from detector components and surrounding environment) backgrounds are considered. A very efficient suppression of background rate is achieved with an outer liquid scintillator veto, liquid xenon skin and fiducialisation. Based on the current measurements of radioactivity of different materials, it is shown thatmore » LZ can achieve the reduction of a total background for a WIMP search down to about 2 events in 1000 live days for 5.6 tonne fiducial mass.« less

Expected background in the LZ experiment

NASA Astrophysics Data System (ADS)

Kudryavtsev, Vitaly A.

2015-08-01

The LZ experiment, featuring a 7-tonne active liquid xenon target, is aimed at achieving unprecedented sensitivity to WIMPs with the background expected to be dominated by astrophysical neutrinos. To reach this goal, extensive simulations are carried out to accurately calculate the electron recoil and nuclear recoil rates in the detector. Both internal (from target material) and external (from detector components and surrounding environment) backgrounds are considered. A very efficient suppression of background rate is achieved with an outer liquid scintillator veto, liquid xenon skin and fiducialisation. Based on the current measurements of radioactivity of different materials, it is shown that LZ can achieve the reduction of a total background for a WIMP search down to about 2 events in 1000 live days for 5.6 tonne fiducial mass.

Genome-wide association of porcine lung lesions using DNA pooling

USDA-ARS?s Scientific Manuscript database

Respiratory disease in swine is a primary health concern for producers. Pleuropneumonia and enzootic pneumonia occur at a high incidence on most farms and have a negative effect on feed efficiency, growth, and animal welfare. Mycoplasma pneumonia is one of the most important because it increases sus...

9 CFR 53.8 - Presentation of claims.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AGRICULTURE COOPERATIVE CONTROL AND ERADICATION OF LIVESTOCK OR POULTRY DISEASES FOOT-AND-MOUTH DISEASE, PLEUROPNEUMONIA, RINDERPEST, AND CERTAIN OTHER COMMUNICABLE DISEASES OF LIVESTOCK OR POULTRY § 53.8 Presentation..., on a form approved by the Administrator: (1) Compensation for the value of animals; (2) The cost of...

9 CFR 53.8 - Presentation of claims.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AGRICULTURE COOPERATIVE CONTROL AND ERADICATION OF LIVESTOCK OR POULTRY DISEASES FOOT-AND-MOUTH DISEASE, PLEUROPNEUMONIA, RINDERPEST, AND CERTAIN OTHER COMMUNICABLE DISEASES OF LIVESTOCK OR POULTRY § 53.8 Presentation..., on a form approved by the Administrator: (1) Compensation for the value of animals; (2) The cost of...

9 CFR 53.8 - Presentation of claims.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AGRICULTURE COOPERATIVE CONTROL AND ERADICATION OF LIVESTOCK OR POULTRY DISEASES FOOT-AND-MOUTH DISEASE, PLEUROPNEUMONIA, RINDERPEST, AND CERTAIN OTHER COMMUNICABLE DISEASES OF LIVESTOCK OR POULTRY § 53.8 Presentation..., on a form approved by the Administrator: (1) Compensation for the value of animals; (2) The cost of...

9 CFR 53.8 - Presentation of claims.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AGRICULTURE COOPERATIVE CONTROL AND ERADICATION OF LIVESTOCK OR POULTRY DISEASES FOOT-AND-MOUTH DISEASE, PLEUROPNEUMONIA, RINDERPEST, AND CERTAIN OTHER COMMUNICABLE DISEASES OF LIVESTOCK OR POULTRY § 53.8 Presentation..., on a form approved by the Administrator: (1) Compensation for the value of animals; (2) The cost of...

9 CFR 53.8 - Presentation of claims.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AGRICULTURE COOPERATIVE CONTROL AND ERADICATION OF LIVESTOCK OR POULTRY DISEASES FOOT-AND-MOUTH DISEASE, PLEUROPNEUMONIA, RINDERPEST, AND CERTAIN OTHER COMMUNICABLE DISEASES OF LIVESTOCK OR POULTRY § 53.8 Presentation..., on a form approved by the Administrator: (1) Compensation for the value of animals; (2) The cost of...

21 CFR 522.2630 - Tulathromycin.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS...) Limitations. Cattle intended for human consumption must not be slaughtered within 18 days from the last... control of SRD associated with A. pleuropneumoniae, P. multocida, and M. hyopneumoniae in groups of pigs...

21 CFR 522.2630 - Tulathromycin.

Code of Federal Regulations, 2012 CFR

2012-04-01

... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS...) Limitations. Cattle intended for human consumption must not be slaughtered within 18 days from the last... control of SRD associated with A. pleuropneumoniae, P. multocida, and M. hyopneumoniae in groups of pigs...

21 CFR 522.2630 - Tulathromycin.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS...) Limitations. Cattle intended for human consumption must not be slaughtered within 18 days from the last... control of SRD associated with A. pleuropneumoniae, P. multocida, and M. hyopneumoniae in groups of pigs...

21 CFR 522.2630 - Tulathromycin.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS...) Limitations. Cattle intended for human consumption must not be slaughtered within 18 days from the last... control of SRD associated with A. pleuropneumoniae, P. multocida, and M. hyopneumoniae in groups of pigs...

The Cosmic Background Explorer

NASA Technical Reports Server (NTRS)

Gulkis, Samuel; Lubin, Philip M.; Meyer, Stephan S.; Silverberg, Robert F.

1990-01-01

The Cosmic Background Explorer (CBE), NASA's cosmological satellite which will observe a radiative relic of the big bang, is discussed. The major questions connected to the big bang theory which may be clarified using the CBE are reviewed. The satellite instruments and experiments are described, including the Differential Microwave Radiometer, which measures the difference between microwave radiation emitted from two points on the sky, the Far-Infrared Absolute Spectrophotometer, which compares the spectrum of radiation from the sky at wavelengths from 100 microns to one cm with that from an internal blackbody, and the Diffuse Infrared Background Experiment, which searches for the radiation from the earliest generation of stars.

A review on natural background radiation

PubMed Central

Shahbazi-Gahrouei, Daryoush; Gholami, Mehrdad; Setayandeh, Samaneh

2013-01-01

The world is naturally radioactive and approximately 82% of human-absorbed radiation doses, which are out of control, arise from natural sources such as cosmic, terrestrial, and exposure from inhalation or intake radiation sources. In recent years, several international studies have been carried out, which have reported different values regarding the effect of background radiation on human health. Gamma radiation emitted from natural sources (background radiation) is largely due to primordial radionuclides, mainly 232Th and 238U series, and their decay products, as well as 40K, which exist at trace levels in the earth's crust. Their concentrations in soil, sands, and rocks depend on the local geology of each region in the world. Naturally occurring radioactive materials generally contain terrestrial-origin radionuclides, left over since the creation of the earth. In addition, the existence of some springs and quarries increases the dose rate of background radiation in some regions that are known as high level background radiation regions. The type of building materials used in houses can also affect the dose rate of background radiations. The present review article was carried out to consider all of the natural radiations, including cosmic, terrestrial, and food radiation. PMID:24223380

Compressive Sensing for Background Subtraction

DTIC Science & Technology

2009-12-20

i) reconstructing an image using only a single optical pho- todiode (infrared, hyperspectral, etc.) along with a digital micromirror device (DMD... curves , we use the full images, run the background subtraction algorithm proposed in [19], and obtain baseline background subtracted images. We then...the images to generate the ROC curve . 5.5 Silhouettes vs. Difference Images We have used a multi camera set up for a 3D voxel reconstruction using the

Demonstration of Cosmic Microwave Background Delensing Using the Cosmic Infrared Background.

PubMed

Larsen, Patricia; Challinor, Anthony; Sherwin, Blake D; Mak, Daisy

2016-10-07

Delensing is an increasingly important technique to reverse the gravitational lensing of the cosmic microwave background (CMB) and thus reveal primordial signals the lensing may obscure. We present a first demonstration of delensing on Planck temperature maps using the cosmic infrared background (CIB). Reversing the lensing deflections in Planck CMB temperature maps using a linear combination of the 545 and 857 GHz maps as a lensing tracer, we find that the lensing effects in the temperature power spectrum are reduced in a manner consistent with theoretical expectations. In particular, the characteristic sharpening of the acoustic peaks of the temperature power spectrum resulting from successful delensing is detected at a significance of 16σ, with an amplitude of A_{delens}=1.12±0.07 relative to the expected value of unity. This first demonstration on data of CIB delensing, and of delensing techniques in general, is significant because lensing removal will soon be essential for achieving high-precision constraints on inflationary B-mode polarization.

Gamma-Ray Background Variability in Mobile Detectors

NASA Astrophysics Data System (ADS)

Aucott, Timothy John

Gamma-ray background radiation significantly reduces detection sensitivity when searching for radioactive sources in the field, such as in wide-area searches for homeland security applications. Mobile detector systems in particular must contend with a variable background that is not necessarily known or even measurable a priori. This work will present measurements of the spatial and temporal variability of the background, with the goal of merging gamma-ray detection, spectroscopy, and imaging with contextual information--a "nuclear street view" of the ubiquitous background radiation. The gamma-ray background originates from a variety of sources, both natural and anthropogenic. The dominant sources in the field are the primordial isotopes potassium-40, uranium-238, and thorium-232, as well as their decay daughters. In addition to the natural background, many artificially-created isotopes are used for industrial or medical purposes, and contamination from fission products can be found in many environments. Regardless of origin, these backgrounds will reduce detection sensitivity by adding both statistical as well as systematic uncertainty. In particular, large detector arrays will be limited by the systematic uncertainty in the background and will suffer from a high rate of false alarms. The goal of this work is to provide a comprehensive characterization of the gamma-ray background and its variability in order to improve detection sensitivity and evaluate the performance of mobile detectors in the field. Large quantities of data are measured in order to study their performance at very low false alarm rates. Two different approaches, spectroscopy and imaging, are compared in a controlled study in the presence of this measured background. Furthermore, there is additional information that can be gained by correlating the gamma-ray data with contextual data streams (such as cameras and global positioning systems) in order to reduce the variability in the background

21 CFR 522.1662a - Oxytetracycline hydrochloride injection.

Code of Federal Regulations, 2011 CFR

2011-04-01

... (scours) (E. coli), foot-rot (Spherophorus necrophorus), diphtheria (Spherophorus necrophorus), wooden...) caused by Escherichia coli, wooden tongue caused by Actinobacillus lignieresi, leptospirosis caused by...) caused by Escherichia coli, pneumonia caused by Pasteurella multocida, and leptospirosis caused by...

21 CFR 522.1662a - Oxytetracycline hydrochloride injection.

Code of Federal Regulations, 2010 CFR

2010-04-01

... (scours) (E. coli), foot-rot (Spherophorus necrophorus), diphtheria (Spherophorus necrophorus), wooden...) caused by Escherichia coli, wooden tongue caused by Actinobacillus lignieresi, leptospirosis caused by...) caused by Escherichia coli, pneumonia caused by Pasteurella multocida, and leptospirosis caused by...

The National Bio- and Agro-Defense Facility: Issues for Congress

DTIC Science & Technology

2007-09-10

bmbl5toc.htm]. 7 For example, research on Nipah virus must be performed in a BSL-4 laboratory. 8 71 Federal Register 3107-3109. agent characterization...African swine fever, Rift Valley fever, Nipah virus, Hendra virus, contagious bovine pleuropneumonia, and Japanese encephalitis.9 The DHS plans to

Studying extragalactic background fluctuations with the Cosmic Infrared Background ExpeRiment 2 (CIBER-2)

NASA Astrophysics Data System (ADS)

Lanz, Alicia; Arai, Toshiaki; Battle, John; Bock, James; Cooray, Asantha; Hristov, Viktor; Korngut, Phillip; Lee, Dae Hee; Mason, Peter; Matsumoto, Toshio; Matsuura, Shuji; Morford, Tracy; Onishi, Yosuke; Shirahata, Mai; Tsumura, Kohji; Wada, Takehiko; Zemcov, Michael

2014-08-01

Fluctuations in the extragalactic background light trace emission from the history of galaxy formation, including the emission from the earliest sources from the epoch of reionization. A number of recent near-infrared measure- ments show excess spatial power at large angular scales inconsistent with models of z < 5 emission from galaxies. These measurements have been interpreted as arising from either redshifted stellar and quasar emission from the epoch of reionization, or the combined intra-halo light from stars thrown out of galaxies during merging activity at lower redshifts. Though astrophysically distinct, both interpretations arise from faint, low surface brightness source populations that are difficult to detect except by statistical approaches using careful observations with suitable instruments. The key to determining the source of these background anisotropies will be wide-field imaging measurements spanning multiple bands from the optical to the near-infrared. The Cosmic Infrared Background ExpeRiment 2 (CIBER-2) will measure spatial anisotropies in the extra- galactic infrared background caused by cosmological structure using six broad spectral bands. The experiment uses three 2048 x 2048 Hawaii-2RG near-infrared arrays in three cameras coupled to a single 28.5 cm telescope housed in a reusable sounding rocket-borne payload. A small portion of each array will also be combined with a linear-variable filter to make absolute measurements of the spectrum of the extragalactic background with high spatial resolution for deep subtraction of Galactic starlight. The large field of view and multiple spectral bands make CIBER-2 unique in its sensitivity to fluctuations predicted by models of lower limits on the luminosity of the first stars and galaxies and in its ability to distinguish between primordial and foreground anisotropies. In this paper the scientific motivation for CIBER-2 and details of its first flight instrumentation will be discussed, including

The Cosmic Background Explorer.

ERIC Educational Resources Information Center

Gulkis, Samuel; And Others

1990-01-01

Outlines the Cosmic Background Explorer (COBE) mission to measure celestial radiation. Describes the instruments used and experiments involving differential microwave radiometers, and a far infrared absolute spectrophotometer. (YP)

Non-perturbative background field calculations

NASA Astrophysics Data System (ADS)

Stephens, C. R.

1988-01-01

New methods are developed for calculating one loop functional determinants in quantum field theory. Instead of relying on a calculation of all the eigenvalues of the small fluctuation equation, these techniques exploit the ability of the proper time formalism to reformulate an infinite dimensional field theoretic problem into a finite dimensional covariant quantum mechanical analog, thereby allowing powerful tools such as the method of Jacobi fields to be used advantageously in a field theory setting. More generally the methods developed herein should be extremely valuable when calculating quantum processes in non-constant background fields, offering a utilitarian alternative to the two standard methods of calculation—perturbation theory in the background field or taking the background field into account exactly. The formalism developed also allows for the approximate calculation of covariances of partial differential equations from a knowledge of the solutions of a homogeneous ordinary differential equation.

Gifted Students from Low-Education Backgrounds

ERIC Educational Resources Information Center

Gibbons, Melinda M.; Pelchar, Taylor K.; Cochran, Jeff L.

2012-01-01

Gifted children from low-education backgrounds often experience barriers to educational and career success. This article reviews the growing body of literature regarding gifted students from low-education backgrounds and the related literature on the challenges and characteristics of first-generation college students. A mother and daughter…

Status of the Simbol-X Background Simulation Activities

NASA Astrophysics Data System (ADS)

Tenzer, C.; Briel, U.; Bulgarelli, A.; Chipaux, R.; Claret, A.; Cusumano, G.; Dell'Orto, E.; Fioretti, V.; Foschini, L.; Hauf, S.; Kendziorra, E.; Kuster, M.; Laurent, P.; Tiengo, A.

2009-05-01

The Simbol-X background simulation group is working towards a simulation based background and mass model which can be used before and during the mission. Using the Geant4 toolkit, a Monte-Carlo code to simulate the detector background of the Simbol-X focal plane instrument has been developed with the aim to optimize the design of the instrument. Achieving an overall low instrument background has direct impact on the sensitivity of Simbol-X and thus will be crucial for the success of the mission. We present results of recent simulation studies concerning the shielding of the detectors with respect to the diffuse cosmic hard X-ray background and to the cosmic-ray proton induced background. Besides estimates of the level and spectral shape of the remaining background expected in the low and high energy detector, also anti-coincidence rates and resulting detector dead time predictions are discussed.

45 CFR 650.16 - Background rights.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 45 Public Welfare 3 2012-10-01 2012-10-01 false Background rights. 650.16 Section 650.16 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION PATENTS § 650.16 Background rights. The Foundation will acquire rights to a research performer's pre-existing technology only...

Clinical Efficacy and Residue Depletion of 10% Enrofloxacin Enteric-Coated Granules in Pigs.

PubMed

Lei, Zhixin; Liu, Qianying; Yang, Bing; Xiong, Jincheng; Li, Kun; Ahmed, Saeed; Hong, Liping; Chen, Pin; He, Qigai; Cao, Jiyue

2017-01-01

A new, more palatable formulation of 10% enrofloxacin enteric-coated granules was investigated to evaluate the pharmacokinetic effect in plasma, the residue elimination in tissues and the clinical efficacy against Actinobacillus pleuropneumonia (APP) and Mycoplasam suis (MS) in pigs. In this study, the enrofloxacin concentrations in plasma and tissues were detected using high-performance liquid chromatography with phosphate buffer (pH = 3) and acetonitrile. The pharmacokinetics and elimination of enrofloxacin enteric-coated granules were performed after oral administration at a single dose of 10 mg/kg body weight (bw) and 5 mg/kg twice per day for 5 consecutive days, respectively. The in vivo antibacterial efficacy and clinical effectiveness of enrofloxacin enteric-coated granules against APP and MS were assayed at 2.5, 5, 10 mg/kg, compared with tiamulin (8 mg/kg) based on establishment of APP and MS infection models. 56 APP strains were selected and tested for in vitro antibacterial activity of enrofloxacin enteric-coated granules. The main parameters of elimination half-life (t 1/2β ), T max , and area under the curve (AUC) were 14.99 ± 4.19, 3.99 ± 0.10, and 38.93 ± 1.52 μg h/ml, respectively, revealing that the enrofloxacin concentration remained high and with a sustainable distribution in plasma. Moreover, the analysis on the evaluation of enrofloxacin and ciprofloxacin in muscle, fat, liver and kidney showed that the recovery were more than 84% recovery in accordance with the veterinary drug residue guidelines of United States pharmacopeia, and the withdrawal periods were 4.28, 3.81, 4.84, and 3.51 days, respectively, suggesting that the withdrawal period was 5 d after oral administration of 5 mg/kg twice per day. The optimal dosage of enrofloxacin enteric-coated granules against APP and MS was 5 mg/kg, with over 90% efficacy, which was significantly different ( p < 0.05) to the 2.5 mg/kg group, but not to the 10 mg/kg group or the positive control

Multi-talker background and semantic priming effect

PubMed Central

Dekerle, Marie; Boulenger, Véronique; Hoen, Michel; Meunier, Fanny

2014-01-01

The reported studies have aimed to investigate whether informational masking in a multi-talker background relies on semantic interference between the background and target using an adapted semantic priming paradigm. In 3 experiments, participants were required to perform a lexical decision task on a target item embedded in backgrounds composed of 1–4 voices. These voices were Semantically Consistent (SC) voices (i.e., pronouncing words sharing semantic features with the target) or Semantically Inconsistent (SI) voices (i.e., pronouncing words semantically unrelated to each other and to the target). In the first experiment, backgrounds consisted of 1 or 2 SC voices. One and 2 SI voices were added in Experiments 2 and 3, respectively. The results showed a semantic priming effect only in the conditions where the number of SC voices was greater than the number of SI voices, suggesting that semantic priming depended on prime intelligibility and strategic processes. However, even if backgrounds were composed of 3 or 4 voices, reducing intelligibility, participants were able to recognize words from these backgrounds, although no semantic priming effect on the targets was observed. Overall this finding suggests that informational masking can occur at a semantic level if intelligibility is sufficient. Based on the Effortfulness Hypothesis, we also suggest that when there is an increased difficulty in extracting target signals (caused by a relatively high number of voices in the background), more cognitive resources were allocated to formal processes (i.e., acoustic and phonological), leading to a decrease in available resources for deeper semantic processing of background words, therefore preventing semantic priming from occurring. PMID:25400572

Foregrounding the Background.

ERIC Educational Resources Information Center

Robbins, Bruce

1998-01-01

Argues that when introductory activities to the classics begin with background information, it can upstage or confine the life of the story, and shows little faith in the students as readers or in the literature itself. Suggests sometimes letting the literature begin, and then helping students make sense of it. Discusses examples from "To Kill a…

Effects of background stimulation upon eye-movement information.

PubMed

Nakamura, S

1996-04-01

To investigate the effects of background stimulation upon eye-movement information (EMI), the perceived deceleration of the target motion during pursuit eye movement (Aubert-Fleishl paradox) was analyzed. In the experiment, a striped pattern was used as a background stimulus with various brightness contrasts and spatial frequencies for serially manipulating the attributions of the background stimulus. Analysis showed that the retinal-image motion of the background stimulus (optic flow) affected eye-movement information and that the effects of optic flow became stronger when high contrast and low spatial frequency stripes were presented as the background stimulus. In conclusion, optic flow is one source of eye-movement information in determining real object motion, and the effectiveness of optic flow depends on the attributes of the background stimulus.

Background Error Correlation Modeling with Diffusion Operators

DTIC Science & Technology

2013-01-01

RESPONSIBLE PERSON 19b. TELEPHONE NUMBER (Include area code) 07-10-2013 Book Chapter Background Error Correlation Modeling with Diffusion Operators...normalization Unclassified Unclassified Unclassified UU 27 Max Yaremchuk (228) 688-5259 Reset Chapter 8 Background error correlation modeling with diffusion ...field, then a structure like this simulates enhanced diffusive transport of model errors in the regions of strong cur- rents on the background of

Social Background, Composition and Educational Growth.

ERIC Educational Resources Information Center

Mare, Robert D.

1979-01-01

Studies the impact of changes in family background on grade-level attainment for White males between 1907-1951. Findings show that the effects of social background on grade attainment decrease with increasing levels of attainment. Reprint available from Institute for Research on Poverty, University of Wisconsin-Madison, Madison WI 53706. (AM)

The Radio Background below 100 MHz

NASA Astrophysics Data System (ADS)

Dowell, Jayce; Taylor, Greg B.

2018-05-01

The recent detection of the “cosmic dawn” redshifted 21 cm signal at 78 MHz by the Experiment to Detect the Global EoR Signatures (EDGES) differs significantly from theoretical predictions. In particular, the absorption trough is roughly a factor of two stronger than the most optimistic theoretical models. The early interpretations of the origin of this discrepancy fall into two categories. The first is that there is increased cooling of the gas due to interactions with dark matter, while the second is that the background radiation field includes a contribution from a component in addition to the cosmic microwave background (CMB). In this Letter we examine the feasibility of the second idea using new data from the first station of the Long Wavelength Array. The data span 40–80 MHz and provide important constraints on the present-day background in a frequency range where there are few surveys with absolute temperature calibration suitable for measuring the strength of the radio monopole. We find support for a strong, diffuse radio background that was suggested by the ARCARDE 2 results in the 3–10 GHz range. We find that this background is well modeled by a power law with a spectral index of ‑2.58 ± 0.05 and a temperature at the rest frame 21 cm frequency of {603}-92+102 mK.

21 CFR 522.313a - Ceftiofur crystalline free acid.

Code of Federal Regulations, 2014 CFR

2014-04-01

... control of SRD associated with A. pleuropneumoniae, P. multocida, H. parasuis, and S. suis in groups of... lactating dairy cattle. For the control of respiratory disease in beef and non-lactating dairy cattle which... crystalline free acid. (1) Each milliliter (mL) contains 100 milligrams (mg) ceftiofur equivalents. (2) Each m...

21 CFR 522.313a - Ceftiofur crystalline free acid.

Code of Federal Regulations, 2013 CFR

2013-04-01

... control of SRD associated with A. pleuropneumoniae, P. multocida, H. parasuis, and S. suis in groups of... lactating dairy cattle. For the control of respiratory disease in beef and non-lactating dairy cattle which... crystalline free acid. (1) Each milliliter (mL) contains 100 milligrams (mg) ceftiofur equivalents. (2) Each m...

9 CFR 93.405 - Health certificate for ruminants.

Code of Federal Regulations, 2010 CFR

2010-01-01

... diseases; and provided further, that for sheep and goats, with respect to contagious pleuropneumonia, the... bovines, sheep, or goats from regions listed as BSE minimal-risk regions in § 94.18(a)(3) of this subchapter, the certificate must also include the name and address of the importer; the species, breed...

14 CFR § 1214.302 - Background.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Background. § 1214.302 Section § 1214.302 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT Payload Specialists for Space Transportation System (STS) Missions § 1214.302 Background. (a) The Space Transportation System (STS) has been...

45 CFR 650.16 - Background rights.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 45 Public Welfare 3 2014-10-01 2014-10-01 false Background rights. 650.16 Section 650.16 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION PATENTS § 650.16 Background rights. The Foundation will acquire rights to a research performer's pre-existing technology only in exceptional circumstances where, du...

45 CFR 650.16 - Background rights.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 45 Public Welfare 3 2010-10-01 2010-10-01 false Background rights. 650.16 Section 650.16 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION PATENTS § 650.16 Background rights. The Foundation will acquire rights to a research performer's pre-existing technology only in exceptional circumstances where, du...

45 CFR 650.16 - Background rights.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 45 Public Welfare 3 2013-10-01 2013-10-01 false Background rights. 650.16 Section 650.16 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION PATENTS § 650.16 Background rights. The Foundation will acquire rights to a research performer's pre-existing technology only in exceptional circumstances where, du...

45 CFR 650.16 - Background rights.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 45 Public Welfare 3 2011-10-01 2011-10-01 false Background rights. 650.16 Section 650.16 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION PATENTS § 650.16 Background rights. The Foundation will acquire rights to a research performer's pre-existing technology only in exceptional circumstances where, du...

Social Background and School Continuation Decisions.

ERIC Educational Resources Information Center

Mare, Robert D.

1980-01-01

Presents a model of the relationship between social background and school continuation decisions among White males born between 1900 and 1950. The model predicts a decline in the effects of social background by the last school transition. Reprint available from Institute for Research on Poverty, University of Wisconsin, Madison, WI 53706. (AM)

Notification: Background Investigation Services

EPA Pesticide Factsheets

Project #OA-FY15-0029, February 26, 2015. The Office of Inspector General (OIG) for the U.S. Environmental Protection Agency (EPA) plans to begin field work for our audit of background investigation services.

Physiologic correlates to background noise acceptance

NASA Astrophysics Data System (ADS)

Tampas, Joanna; Harkrider, Ashley; Nabelek, Anna

2004-05-01

Acceptance of background noise can be evaluated by having listeners indicate the highest background noise level (BNL) they are willing to accept while following the words of a story presented at their most comfortable listening level (MCL). The difference between the selected MCL and BNL is termed the acceptable noise level (ANL). One of the consistent findings in previous studies of ANL is large intersubject variability in acceptance of background noise. This variability is not related to age, gender, hearing sensitivity, personality, type of background noise, or speech perception in noise performance. The purpose of the current experiment was to determine if individual differences in physiological activity measured from the peripheral and central auditory systems of young female adults with normal hearing can account for the variability observed in ANL. Correlations between ANL and various physiological responses, including spontaneous, click-evoked, and distortion-product otoacoustic emissions, auditory brainstem and middle latency evoked potentials, and electroencephalography will be presented. Results may increase understanding of the regions of the auditory system that contribute to individual noise acceptance.

The cosmic microwave background radiation

NASA Technical Reports Server (NTRS)

Silk, Joseph

1992-01-01

A review the implications of the spectrum and anisotropy of the cosmic microwave background for cosmology. Thermalization and processes generating spectral distortions are discussed. Anisotropy predictions are described and compared with observational constraints. If the evidence for large-scale power in the galaxy distribution in excess of that predicted by the cold dark matter model is vindicated, and the observed structure originated via gravitational instabilities of primordial density fluctuations, the predicted amplitude of microwave background anisotropies on angular scales of a degree and larger must be at least several parts in 10 exp 6.

Urban Background Study Webinar

EPA Pesticide Factsheets

This webinar presented the methodology developed for collecting a city-wide or urban area background data set, general results of southeastern cities data collected to date, and a case study that used this sampling method.

Characterizing the True Background Corona with SDO/AIA

NASA Technical Reports Server (NTRS)

Napier, Kate; Winebarger, Amy; Alexander, Caroline

2014-01-01

Characterizing the nature of the solar coronal background would enable scientists to more accurately determine plasma parameters, and may lead to a better understanding of the coronal heating problem. Because scientists study the 3D structure of the Sun in 2D, any line of sight includes both foreground and background material, and thus, the issue of background subtraction arises. By investigating the intensity values in and around an active region, using multiple wavelengths collected from the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) over an eight-hour period, this project aims to characterize the background as smooth or structured. Different methods were employed to measure the true coronal background and create minimum intensity images. These were then investigated for the presence of structure. The background images created were found to contain long-lived structures, including coronal loops, that were still present in all of the wavelengths, 193 Angstroms,171 Angstroms,131 Angstroms, and 211 Angstroms. The intensity profiles across the active region indicate that the background is much more structured than previously thought.

Background derivation and image flattening: getimages

NASA Astrophysics Data System (ADS)

Men'shchikov, A.

2017-11-01

Modern high-resolution images obtained with space observatories display extremely strong intensity variations across images on all spatial scales. Source extraction in such images with methods based on global thresholding may bring unacceptably large numbers of spurious sources in bright areas while failing to detect sources in low-background or low-noise areas. It would be highly beneficial to subtract background and equalize the levels of small-scale fluctuations in the images before extracting sources or filaments. This paper describes getimages, a new method of background derivation and image flattening. It is based on median filtering with sliding windows that correspond to a range of spatial scales from the observational beam size up to a maximum structure width Xλ. The latter is a single free parameter of getimages that can be evaluated manually from the observed image ℐλ. The median filtering algorithm provides a background image \\tilde{Bλ} for structures of all widths below Xλ. The same median filtering procedure applied to an image of standard deviations 𝓓λ derived from a background-subtracted image \\tilde{Sλ} results in a flattening image \\tilde{Fλ}. Finally, a flattened detection image I{λD} = \\tilde{Sλ}/\\tilde{Fλ} is computed, whose standard deviations are uniform outside sources and filaments. Detecting sources in such greatly simplified images results in much cleaner extractions that are more complete and reliable. As a bonus, getimages reduces various observational and map-making artifacts and equalizes noise levels between independent tiles of mosaicked images.

Modeled summer background concentration nutrients and ...

EPA Pesticide Factsheets

We used regression models to predict background concentration of four water quality indictors: total nitrogen (N), total phosphorus (P), chloride, and total suspended solids (TSS), in the mid-continent (USA) great rivers, the Upper Mississippi, the Lower Missouri, and the Ohio. From best-model linear regressions of water quality indicators with land use and other stressor variables, we determined the concentration of the indicators when the land use and stressor variables were all set to zero the y-intercept. Except for total P on the Upper Mississippi River and chloride on the Ohio River, we were able to predict background concentration from significant regression models. In every model with more than one predictor variable, the model included at least one variable representing agricultural land use and one variable representing development. Predicted background concentration of total N was the same on the Upper Mississippi and Lower Missouri rivers (350 ug l-1), which was much lower than a published eutrophication threshold and percentile-based thresholds (25th percentile of concentration at all sites in the population) but was similar to a threshold derived from the response of sestonic chlorophyll a to great river total N concentration. Background concentration of total P on the Lower Missouri (53 ug l-1) was also lower than published and percentile-based thresholds. Background TSS concentration was higher on the Lower Missouri (30 mg l-1) than the other ri

The isotropic radio background revisited

NASA Astrophysics Data System (ADS)

Fornengo, Nicolao; Lineros, Roberto A.; Regis, Marco; Taoso, Marco

2014-04-01

We present an extensive analysis on the determination of the isotropic radio background. We consider six different radio maps, ranging from 22 MHz to 2.3 GHz and covering a large fraction of the sky. The large scale emission is modeled as a linear combination of an isotropic component plus the Galactic synchrotron radiation and thermal bremsstrahlung. Point-like and extended sources are either masked or accounted for by means of a template. We find a robust estimate of the isotropic radio background, with limited scatter among different Galactic models. The level of the isotropic background lies significantly above the contribution obtained by integrating the number counts of observed extragalactic sources. Since the isotropic component dominates at high latitudes, thus making the profile of the total emission flat, a Galactic origin for such excess appears unlikely. We conclude that, unless a systematic offset is present in the maps, and provided that our current understanding of the Galactic synchrotron emission is reasonable, extragalactic sources well below the current experimental threshold seem to account for the majority of the brightness of the extragalactic radio sky.

The EPIC-MOS Particle-Induced Background Spectra

NASA Technical Reports Server (NTRS)

Kuntz, K. D.; Sowden, S. L.

2007-01-01

In order to analyse diffuse emission that fills the field of view, one must accurately characterize the instrumental backgrounds. For the XMM-Newton EPIC instrument these backgrounds include a temporally variable "quiescent" component. as well as the strongly variable soft proton contamination. We have characterized the spectral and spatial response of the EPIC detectors to these background components and have developed tools to remove these backgrounds from observations. The "quiescent" component was characterized using a combination of the filter-wheel-closed data and a database of unexposed-region data. The soft proton contamination was characterized by differencing images and spectra taken during flared and flare-free intervals. After application of our modeled backgrounds, the differences between independent observations of the same region of "blank sky" are consistent with the statistical uncertainties except when there is clear spectral evidence of solar wind charge exchange emission. Using a large sample of blank sky data, we show that strong magnetospheric SWCX emission requires elevated solar wind fluxes; observations through the densest part of the magnetosheath are not necessarily strongly contaminated with SWCX emission.

21 CFR 522.313a - Ceftiofur crystalline free acid.

Code of Federal Regulations, 2012 CFR

2012-04-01

... control of SRD associated with A. pleuropneumoniae, P. multocida, H. parasuis, and S. suis in groups of... cattle. For the control of respiratory disease in beef and non-lactating dairy cattle which are at high... crystalline free acid. (1) Each milliliter (mL) contains 100 milligrams (mg) ceftiofur equivalents. (2) Each m...

21 CFR 522.313a - Ceftiofur crystalline free acid.

Code of Federal Regulations, 2011 CFR

2011-04-01

... control of SRD associated with A. pleuropneumoniae, P. multocida, H. parasuis, and S. suis in groups of... cattle. For the control of respiratory disease in beef and non-lactating dairy cattle which are at high... crystalline free acid. (1) Each milliliter (mL) contains 100 milligrams (mg) ceftiofur equivalents. (2) Each m...

9 CFR 53.1 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., contagious pleuropneumonia, exotic Newcastle disease, highly pathogenic avian influenza, infectious salmon... influenza. (1) Any influenza virus that kills at least 75 percent of eight 4- to 6-week-old susceptible... pathogenic avian influenza viruses; or (3) Any influenza virus that is not an H5 or H7 subtype and that kills...

9 CFR 53.1 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., contagious pleuropneumonia, exotic Newcastle disease, highly pathogenic avian influenza, infectious salmon... influenza. (1) Any influenza virus that kills at least 75 percent of eight 4- to 6-week-old susceptible... pathogenic avian influenza viruses; or (3) Any influenza virus that is not an H5 or H7 subtype and that kills...

9 CFR 53.1 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., contagious pleuropneumonia, exotic Newcastle disease, highly pathogenic avian influenza, infectious salmon... influenza. (1) Any influenza virus that kills at least 75 percent of eight 4- to 6-week-old susceptible... pathogenic avian influenza viruses; or (3) Any influenza virus that is not an H5 or H7 subtype and that kills...

The EPIC-MOS Particle-Induced Background Spectrum

NASA Technical Reports Server (NTRS)

Kuntz, K. D.; Snowden, S. L.

2006-01-01

We have developed a method for constructing a spectrum of the particle-induced instrumental background of the XMM-Newton EPIC MOS detectors that can be used for observations of the diffuse background and extended sources that fill a significant fraction of the instrument field of view. The strength and spectrum of the particle-induced background, that is, the background due to the interaction of particles with the detector and the detector surroundings, is temporally variable as well as spatially variable over individual chips. Our method uses a combination of the filter-wheel-closed data and a database of unexposed-region data to construct a spectrum of the "quiescent" background. We show that, using this method of background subtraction, the differences between independent observations of the same region of "blank sky" are consistent with the statistical uncertainties except when there is clear evidence of solar wind charge exchange emission. We use the blank sky observations to show that contamination by SWCX emission is a strong function of the solar wind proton flux, and that observations through the flanks of the magnetosheath appear to be contaminated only at much higher solar wind fluxes. We have also developed a spectral model of the residual soft proton flares, which allows their effects to be removed to a substantial degree during spectral fitting.

Equivalent background speed in recovery from motion adaptation.

PubMed

Simpson, W A; Newman, A; Aasland, W

1997-01-01

We measured, in the same observers, (1) the detectability, d, of a small rotational jump following adaptation to rotational motion and (2) the detectability of the same jump when superimposed on one of several background rotation speeds. Following 90 s of motion adaptation the detectability of the jump was impaired, and sensitivity slowly recovered over the course of 60 s. The detectability of the jump was also impaired by the background speed in a way consistent with a quadratic form of Weber's law. We propose that motion adaptation impairs the detectability of the small jump because it is as if an equivalent background speed has been superimposed on the display. We measured the equivalent background by finding the real background speed that produced the same d' at each instant in the recovery from motion adaptation. The equivalent background started at approximately one to two thirds the speed of the adapting motion, declined rapidly, rose to a small peak at 30 s, then disappeared by 60 s. Since the equivalent background speed corresponds to the speed of the motion aftereffect, we have measured the time course of the motion aftereffect with objective psychophysics.

Generative electronic background music system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mazurowski, Lukasz

In this short paper-extended abstract the new approach to generation of electronic background music has been presented. The Generative Electronic Background Music System (GEBMS) has been located between other related approaches within the musical algorithm positioning framework proposed by Woller et al. The music composition process is performed by a number of mini-models parameterized by further described properties. The mini-models generate fragments of musical patterns used in output composition. Musical pattern and output generation are controlled by container for the mini-models - a host-model. General mechanism has been presented including the example of the synthesized output compositions.

Background in X-ray astronomy proportional counters

NASA Technical Reports Server (NTRS)

Bower, C. R.; Dietz, K. L.; Ramsey, B. D.; Weisskopf, M. C.

1991-01-01

The authors report the results of an investigation into the nature of background events in proportional counters sensitive to X-ray photons having energy of less than 150 keV. Even with the use of thick shields composed of high-atomic-number material, a significant flux background in the detector's energy region can result from multiple Compton scattering in the mass surrounding the active region of the detector. The importance of the selection of detector components in the reduction of the background by more than an order of magnitude is emphasized. Experimental results are shown to agree qualitatively with Monte Carlo simulations. It is concluded that escape gating is a powerful means of determining the nature of background in flight detectors: the single/pair ratios reveal whether the detected events are charged particles or photons.

CUORE and Background Reduction Case Studies for CUPID

NASA Astrophysics Data System (ADS)

Sakai, Michinari; Gozlukluoglu, Nihal; Huang, Huan; Cuore Collaboration

2017-09-01

CUORE (Cryogenic Underground Observatory for Rare Events) is a bolometric experiment at cryogenic temperatures currently in operation to search for neutrinoless double beta decay. Successful detection of this extremely rare process requires stringent control of radioactive backgrounds of the experiment as well as the detector itself. Great care was taken in CUORE to select the materials and various parts that comprise the current detector. However next-generation neutrinoless double beta decay experiments face a challenge to further reduce backgrounds in order to probe more deeply into the effective Majorana neutrino mass phase space. In this presentation we will review the sensitivity and background budget for the currently running experiment CUORE, as well as the target sensitivity and background goals for the next generation experiment CUPID that will cover the inverted neutrino mass hierarchy. We will explore simulation based R&D case studies for background reduction and lay out achievable background reduction levels using possible materials and feasible geometries in the context of CUPID. National Science Foundation.

Effects of background motion on eye-movement information.

PubMed

Nakamura, S

1997-02-01

The effect of background stimulus on eye-movement information was investigated by analyzing the underestimation of the target velocity during pursuit eye movement (Aubert-Fleishl paradox). In the experiment, a striped pattern with various brightness contrasts and spatial frequencies was used as a background stimulus, which was moved at various velocities. Analysis showed that the perceived velocity of the pursuit target, which indicated the magnitudes of eye-movement information, decreased when the background stripes moved in the same direction as eye movement at higher velocities and increased when the background moved in the opposite direction. The results suggest that the eye-movement information varied as a linear function of the velocity of the motion of the background retinal image (optic flow). In addition, the effectiveness of optic flow on eye-movement information was determined by the attributes of the background stimulus such as the brightness contrast or the spatial frequency of the striped pattern.

Modeling background radiation in Southern Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haber, Daniel A.; Burnley, Pamela C.; Adcock, Christopher T.

Aerial gamma ray surveys are an important tool for national security, scientific, and industrial interests in determining locations of both anthropogenic and natural sources of radioactivity. There is a relationship between radioactivity and geology and in the past this relationship has been used to predict geology from an aerial survey. The purpose of this project is to develop a method to predict the radiologic exposure rate of the geologic materials by creating a high resolution background model. The intention is for this method to be used in an emergency response scenario where the background radiation envi-ronment is unknown. Two studymore » areas in Southern Nevada have been modeled using geologic data, images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), geochemical data, and pre-existing low resolution aerial surveys from the National Uranium Resource Evaluation (NURE) Survey. Using these data, geospatial areas that are homogenous in terms of K, U, and Th, referred to as background radiation units, are defined and the gamma ray exposure rate is predicted. The prediction is compared to data collected via detailed aerial survey by the Department of Energy's Remote Sensing Lab - Nellis, allowing for the refinement of the technique. By using geologic units to define radiation background units of exposed bedrock and ASTER visualizations to subdivide and define radiation background units within alluvium, successful models have been produced for Government Wash, north of Lake Mead, and for the western shore of Lake Mohave, east of Searchlight, NV.« less

Modeling background radiation in Southern Nevada

DOE PAGES

Haber, Daniel A.; Burnley, Pamela C.; Adcock, Christopher T.; ...

2017-02-06

Aerial gamma ray surveys are an important tool for national security, scientific, and industrial interests in determining locations of both anthropogenic and natural sources of radioactivity. There is a relationship between radioactivity and geology and in the past this relationship has been used to predict geology from an aerial survey. The purpose of this project is to develop a method to predict the radiologic exposure rate of the geologic materials by creating a high resolution background model. The intention is for this method to be used in an emergency response scenario where the background radiation envi-ronment is unknown. Two studymore » areas in Southern Nevada have been modeled using geologic data, images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), geochemical data, and pre-existing low resolution aerial surveys from the National Uranium Resource Evaluation (NURE) Survey. Using these data, geospatial areas that are homogenous in terms of K, U, and Th, referred to as background radiation units, are defined and the gamma ray exposure rate is predicted. The prediction is compared to data collected via detailed aerial survey by the Department of Energy's Remote Sensing Lab - Nellis, allowing for the refinement of the technique. By using geologic units to define radiation background units of exposed bedrock and ASTER visualizations to subdivide and define radiation background units within alluvium, successful models have been produced for Government Wash, north of Lake Mead, and for the western shore of Lake Mohave, east of Searchlight, NV.« less

Background modeling for the GERDA experiment

NASA Astrophysics Data System (ADS)

Becerici-Schmidt, N.; Gerda Collaboration

2013-08-01

The neutrinoless double beta (0νββ) decay experiment GERDA at the LNGS of INFN has started physics data taking in November 2011. This paper presents an analysis aimed at understanding and modeling the observed background energy spectrum, which plays an essential role in searches for a rare signal like 0νββ decay. A very promising preliminary model has been obtained, with the systematic uncertainties still under study. Important information can be deduced from the model such as the expected background and its decomposition in the signal region. According to the model the main background contributions around Qββ come from 214Bi, 228Th, 42K, 60Co and α emitting isotopes in the 226Ra decay chain, with a fraction depending on the assumed source positions.

Low background screening capability in the UK

NASA Astrophysics Data System (ADS)

Ghag, Chamkaur

2015-08-01

Low background rare event searches in underground laboratories seeking observation of direct dark matter interactions or neutrino-less double beta decay have the potential to profoundly advance our understanding of the physical universe. Successful results from these experiments depend critically on construction from extremely radiologically clean materials and accurate knowledge of subsequent low levels of expected background. The experiments must conduct comprehensive screening campaigns to reduce radioactivity from detector components, and these measurements also inform detailed characterisation and quantification of background sources and their impact, necessary to assign statistical significance to any potential discovery. To provide requisite sensitivity for material screening and characterisation in the UK to support our rare event search activities, we have re-developed our infrastructure to add ultra-low background capability across a range of complementary techniques that collectively allow complete radioactivity measurements. Ultra-low background HPGe and BEGe detectors have been installed at the Boulby Underground Laboratory, itself undergoing substantial facility re-furbishment, to provide high sensitivity gamma spectroscopy in particular for measuring the uranium and thorium decay series products. Dedicated low-activity mass spectrometry instrumentation has been developed at UCL for part per trillion level contaminant identification to complement underground screening with direct U and Th measurements, and meet throughput demands. Finally, radon emanation screening at UCL measures radon background inaccessible to gamma or mass spectrometry techniques. With this new capability the UK is delivering half of the radioactivity screening for the LZ dark matter search experiment.

Optimal Background Estimators in Single-Molecule FRET Microscopy.

PubMed

Preus, Søren; Hildebrandt, Lasse L; Birkedal, Victoria

2016-09-20

Single-molecule total internal reflection fluorescence (TIRF) microscopy constitutes an umbrella of powerful tools that facilitate direct observation of the biophysical properties, population heterogeneities, and interactions of single biomolecules without the need for ensemble synchronization. Due to the low signal/noise ratio in single-molecule TIRF microscopy experiments, it is important to determine the local background intensity, especially when the fluorescence intensity of the molecule is used quantitatively. Here we compare and evaluate the performance of different aperture-based background estimators used particularly in single-molecule Förster resonance energy transfer. We introduce the general concept of multiaperture signatures and use this technique to demonstrate how the choice of background can affect the measured fluorescence signal considerably. A new, to our knowledge, and simple background estimator is proposed, called the local statistical percentile (LSP). We show that the LSP background estimator performs as well as current background estimators at low molecular densities and significantly better in regions of high molecular densities. The LSP background estimator is thus suited for single-particle TIRF microscopy of dense biological samples in which the intensity itself is an observable of the technique. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Perfluorocarbon background concentrations in Europe

NASA Astrophysics Data System (ADS)

Straume, Anne Grete; Dietz, Russel N.; Koffı̀, Ernest N.'dri; Nodop, Katrin

Five studies of the background level of several perfluorocarbon compounds in Europe are here presented together with measurements from the European Tracer Experiment (ETEX). The tracers used during the two ETEX tracer releases were the perfluorocarbons (PFCs); perfluoromethylcyclohexane (C 7F 14, PMCH) and perfluoromethylcyclopentane (C 6F 12, PMCP). Their background concentrations were detected by using both passive and active sampling techniques, to define the spatial and temporal variation of the PFCs over Europe. Also the background variations of four isomers of the PFC compound perfluorodimethylcyclohexane (C 8F 16, PDCH) were studied. The results were compared to other PFC tracer studies in the U.S.A. and Europe. The mean and median values of the measured PFCs were found to vary slightly and randomly in space and time. They were found to be higher and to have a larger standard deviation than the measurements from the American studies. The background concentrations were still found to be low and stable enough for PFCs to be highly suitable for use in tracer studies. The following concentrations were found: PMCP; 4.6±0.3 fl ℓ -1, PMCH: 4.6±0.8 fl ℓ -1, ocPDCH: 0.96±0.33 fl ℓ -1, mtPDCH: 9.3±0.8 fl ℓ -1, mcPDCH: 8.8±0.8 fl ℓ -1, ptPDCH: 6.1±0.8 fl ℓ -1. A study of the correlation between the measured PFC compounds showed a significant correlation between most of the compounds, which indicate that there are no major PFC sources in Europe.

Background radiation measurements at high power research reactors

NASA Astrophysics Data System (ADS)

Ashenfelter, J.; Balantekin, B.; Baldenegro, C. X.; Band, H. R.; Barclay, G.; Bass, C. D.; Berish, D.; Bowden, N. S.; Bryan, C. D.; Cherwinka, J. J.; Chu, R.; Classen, T.; Davee, D.; Dean, D.; Deichert, G.; Dolinski, M. J.; Dolph, J.; Dwyer, D. A.; Fan, S.; Gaison, J. K.; Galindo-Uribarri, A.; Gilje, K.; Glenn, A.; Green, M.; Han, K.; Hans, S.; Heeger, K. M.; Heffron, B.; Jaffe, D. E.; Kettell, S.; Langford, T. J.; Littlejohn, B. R.; Martinez, D.; McKeown, R. D.; Morrell, S.; Mueller, P. E.; Mumm, H. P.; Napolitano, J.; Norcini, D.; Pushin, D.; Romero, E.; Rosero, R.; Saldana, L.; Seilhan, B. S.; Sharma, R.; Stemen, N. T.; Surukuchi, P. T.; Thompson, S. J.; Varner, R. L.; Wang, W.; Watson, S. M.; White, B.; White, C.; Wilhelmi, J.; Williams, C.; Wise, T.; Yao, H.; Yeh, M.; Yen, Y.-R.; Zhang, C.; Zhang, X.; Prospect Collaboration

2016-01-01

Research reactors host a wide range of activities that make use of the intense neutron fluxes generated at these facilities. Recent interest in performing measurements with relatively low event rates, e.g. reactor antineutrino detection, at these facilities necessitates a detailed understanding of background radiation fields. Both reactor-correlated and naturally occurring background sources are potentially important, even at levels well below those of importance for typical activities. Here we describe a comprehensive series of background assessments at three high-power research reactors, including γ-ray, neutron, and muon measurements. For each facility we describe the characteristics and identify the sources of the background fields encountered. The general understanding gained of background production mechanisms and their relationship to facility features will prove valuable for the planning of any sensitive measurement conducted therein.

76 FR 79565 - Management Contracts-Background Investigations

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-22

... Management Contracts--Background Investigations AGENCY: National Indian Gaming Commission. ACTION: Notice of... investigation process required for management contracts. The proposed revision may reduce duplication of efforts... to clarify that a management contractor should be required to submit background information when the...

Agricultural Bioterrorism: A Federal Strategy to Meet the Threat

DTIC Science & Technology

2002-01-01

sickness* Anthrax Avian influenza* Foot and mouth disease* Bluetongue* Hog cholera/classical swine fever* Bovine spongiform encephalopathy* Ornithosis...Psittacocis Contagious bovine pleuropneumonia* Rinderpest* Lumpy skin disease* Trypanosomiasis Newcastle disease* Poxvirus Paratuberculosis/Johne’s...including the animal diseases Bovine Spongi- form Encephalopathy, as well as Hendrah and Nipah viruses.154 An ex- panded research initiative should

Thermal background noise limitations

NASA Technical Reports Server (NTRS)

Gulkis, S.

1982-01-01

Modern detection systems are increasingly limited in sensitivity by the background thermal photons which enter the receiving system. Expressions for the fluctuations of detected thermal radiation are derived. Incoherent and heterodyne detection processes are considered. References to the subject of photon detection statistics are given.

Stacked Multilayer Self-Organizing Map for Background Modeling.

PubMed

Zhao, Zhenjie; Zhang, Xuebo; Fang, Yongchun

2015-09-01

In this paper, a new background modeling method called stacked multilayer self-organizing map background model (SMSOM-BM) is proposed, which presents several merits such as strong representative ability for complex scenarios, easy to use, and so on. In order to enhance the representative ability of the background model and make the parameters learned automatically, the recently developed idea of representative learning (or deep learning) is elegantly employed to extend the existing single-layer self-organizing map background model to a multilayer one (namely, the proposed SMSOM-BM). As a consequence, the SMSOM-BM gains several merits including strong representative ability to learn background model of challenging scenarios, and automatic determination for most network parameters. More specifically, every pixel is modeled by a SMSOM, and spatial consistency is considered at each layer. By introducing a novel over-layer filtering process, we can train the background model layer by layer in an efficient manner. Furthermore, for real-time performance consideration, we have implemented the proposed method using NVIDIA CUDA platform. Comparative experimental results show superior performance of the proposed approach.

Background-Modeling-Based Adaptive Prediction for Surveillance Video Coding.

PubMed

Zhang, Xianguo; Huang, Tiejun; Tian, Yonghong; Gao, Wen

2014-02-01

The exponential growth of surveillance videos presents an unprecedented challenge for high-efficiency surveillance video coding technology. Compared with the existing coding standards that were basically developed for generic videos, surveillance video coding should be designed to make the best use of the special characteristics of surveillance videos (e.g., relative static background). To do so, this paper first conducts two analyses on how to improve the background and foreground prediction efficiencies in surveillance video coding. Following the analysis results, we propose a background-modeling-based adaptive prediction (BMAP) method. In this method, all blocks to be encoded are firstly classified into three categories. Then, according to the category of each block, two novel inter predictions are selectively utilized, namely, the background reference prediction (BRP) that uses the background modeled from the original input frames as the long-term reference and the background difference prediction (BDP) that predicts the current data in the background difference domain. For background blocks, the BRP can effectively improve the prediction efficiency using the higher quality background as the reference; whereas for foreground-background-hybrid blocks, the BDP can provide a better reference after subtracting its background pixels. Experimental results show that the BMAP can achieve at least twice the compression ratio on surveillance videos as AVC (MPEG-4 Advanced Video Coding) high profile, yet with a slightly additional encoding complexity. Moreover, for the foreground coding performance, which is crucial to the subjective quality of moving objects in surveillance videos, BMAP also obtains remarkable gains over several state-of-the-art methods.

[Invasive infections caused by Haemophilus influenzae type b after the institution of the conjugated vaccine on the expanded programm on immunization in Chile].

PubMed

Cruces R, Pablo; Donoso F, Alejandro; Camacho A, Jorge; Llorente H, Marcela

2006-03-01

After almost a decade since the introduction of Haemophilus influenzae type b (Hib) conjugate vaccines in Chile (in a 2-4-6 month schedule), Hib invasive infections have dramatically decreased, albeit they remain to occasionally produce disease in pediatric patients. We report our experience with children whom developed Hib invasive disease in children since 2000 to 2004. Medical records of children with Hib were reviewed in order to describe the epidemiology, main clinical and laboratory findings, management and complications. Twenty three patients (17 male), between 1 and 71 months (median 30 months) were identified: pneumonia (7), meningitis (4), pleuropneumonia (2), empyema (2), sepsis (2), cellulitis (2), meningitis and pleuropneumonia (1), purpura fulminans (1), miositis (1) and epiglottitis (1). No deaths were observed and four patients presented severe sequelae at hospital discharge. Twenty patients were considered vaccine failures. Hib remains as a sporadic cause of severe disease in Chile and thus for physicians should still keep it in mind. Case analysis and active surveillance are necessary to monitor the current immunization regimen.

X-Ray Background Survey Spectrometer (XBSS)

NASA Technical Reports Server (NTRS)

Sanders, W. T. (Principal Investigator); Paulos, R. J.

1996-01-01

The objective of this investigation was to perform a spectral survey of the low energy diffuse X-ray background using the X-ray Background Survey Spectrometer (XBSS) on board the Space Station Freedom (SSF). XBSS obtains spectra of the X-ray diffuse background in the 11-24 A and 44-84 A wavelength intervals over the entire sky with 15 deg spatial resolution. These X-rays are almost certainly from a very hot (10(exp 6) K) component of the interstellar medium that is contained in regions occupying a large fraction of the interstellar volume near the Sun. Astrophysical plasmas near 10(exp 6) K are rich in emission lines, and the relative strengths of these lines, besides providing information about the physical conditions of the emitting gas, also provide information about its history and heating mechanisms.

Taiwan: Background Notes Series.

ERIC Educational Resources Information Center

Reams, Joanne Reppert

Concise background information on Taiwan is provided. The publication begins with a profile of Taiwan, discussing the people, geography, political establishment, and economy. A map of the country is provided. The bulk of the publication then provides more detailed information on Taiwan's people, geography, history, administration, political…

Scientific results from the Cosmic Background Explorer (COBE)

PubMed Central

Bennett, C. L.; Boggess, N. W.; Cheng, E. S.; Hauser, M. G.; Kelsall, T.; Mather, J. C.; Moseley, S. H.; Murdock, T. L.; Shafer, R. A.; Silverberg, R. F.; Smoot, G. F.; Weiss, R.; Wright, E. L.

1993-01-01

The National Aeronautics and Space Administration (NASA) has flown the COBE satellite to observe the Big Bang and the subsequent formation of galaxies and large-scale structure. Data from the Far-Infrared Absolute Spectrophotometer (FIRAS) show that the spectrum of the cosmic microwave background is that of a black body of temperature T = 2.73 ± 0.06 K, with no deviation from a black-body spectrum greater than 0.25% of the peak brightness. The data from the Differential Microwave Radiometers (DMR) show statistically significant cosmic microwave background anisotropy, consistent with a scale-invariant primordial density fluctuation spectrum. Measurements from the Diffuse Infrared Background Experiment (DIRBE) provide new conservative upper limits to the cosmic infrared background. Extensive modeling of solar system and galactic infrared foregrounds is required for further improvement in the cosmic infrared background limits. PMID:11607383

X-Ray Background from Early Binaries

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-11-01

What impact did X-rays from the first binary star systems have on the universe around them? A new study suggests this radiation may have played an important role during the reionization of our universe.Ionizing the UniverseDuring the period of reionization, the universe reverted from being neutral (as it was during recombination, the previous period)to once again being ionized plasma a state it has remained in since then. This transition, which occurred between 150 million and one billion years after the Big Bang (redshift of 6 z 20), was caused by the formation of the first objects energetic enough to reionize the universes neutral hydrogen.ROSAT image of the soft X-ray background throughout the universe. The different colors represent different energy bands: 0.25 keV (red), 0.75 keV (green), 1.5 keV (blue). [NASA/ROSAT Project]Understanding this time period in particular, determining what sources caused the reionization, and what the properties were of the gas strewn throughout the universe during this time is necessary for us to be able to correctly interpret cosmological observations.Conveniently, the universe has provided us with an interesting clue: the large-scale, diffuse X-ray background we observe all around us. What produced these X-rays, and what impact did this radiation have on the intergalactic medium long ago?The First BinariesA team of scientists led by Hao Xu (UC San Diego) has suggested that the very first generation of stars might be an important contributor to these X-rays.This hypothetical first generation, Population III stars, are thought to have formed before and during reionization from large clouds of gas containing virtually no metals. Studies suggest that a large fraction of Pop III stars formed in binaries and when those stars ended their lives as black holes, ensuing accretion from their companions could produceX-ray radiation.The evolution with redshift of the mean X-ray background intensities. Each curve represents a different

China: Background Notes Series.

ERIC Educational Resources Information Center

Reams, Joanne Reppert

Concise background information on the People's Republic of China is provided. The publication begins with a profile of the country, outlining the people, geography, economy, and membership in international organizations. The bulk of the document then discusses in more detail China's people, geography, history, government, education, economy, and…

7 CFR 3407.1 - Background and purpose.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 15 2011-01-01 2011-01-01 false Background and purpose. 3407.1 Section 3407.1 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND AGRICULTURE IMPLEMENTATION OF NATIONAL ENVIRONMENTAL POLICY ACT § 3407.1 Background and purpose. (a) The...

7 CFR 3407.1 - Background and purpose.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 15 2014-01-01 2014-01-01 false Background and purpose. 3407.1 Section 3407.1 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND AGRICULTURE IMPLEMENTATION OF NATIONAL ENVIRONMENTAL POLICY ACT § 3407.1 Background and purpose. (a) The...

7 CFR 3407.1 - Background and purpose.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 15 2013-01-01 2013-01-01 false Background and purpose. 3407.1 Section 3407.1 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND AGRICULTURE IMPLEMENTATION OF NATIONAL ENVIRONMENTAL POLICY ACT § 3407.1 Background and purpose. (a) The...

7 CFR 3407.1 - Background and purpose.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 15 2012-01-01 2012-01-01 false Background and purpose. 3407.1 Section 3407.1 Agriculture Regulations of the Department of Agriculture (Continued) NATIONAL INSTITUTE OF FOOD AND AGRICULTURE IMPLEMENTATION OF NATIONAL ENVIRONMENTAL POLICY ACT § 3407.1 Background and purpose. (a) The...

44 CFR 10.1 - Background and purpose.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Background and purpose. 10.1 Section 10.1 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY GENERAL ENVIRONMENTAL CONSIDERATIONS General § 10.1 Background and purpose. (a) This part...

Environmental context effects of background color in free recall.

PubMed

Isarida, Taeo; Isarin, Tosmko K

2007-10-01

In four experiments, we investigated background-color context effects in free recall. A total of 194 undergraduates studied words presented one by one against a background color, and oral free recall was tested after a 30-sec filled retention interval. A signal for recall was presented against a background color throughout the test. Recalled items were classified as same- and different-context items according to whether the background colors at study and test were the same or different. Significant context effects were found in Experiments I and 2, in which two background colors were randomly alternated word by word. No context effects were found in Experiments 3 and 4, in which a common background color was presented for all items (Experiment 3) or for a number of successive items (Experiment 4). The results indicate that a change in background colors is necessary and sufficient to produce context effects. Implications of the present findings are discussed.

Background Model for the Majorana Demonstrator

NASA Astrophysics Data System (ADS)

Cuesta, C.; Abgrall, N.; Aguayo, E.; Avignone, F. T.; Barabash, A. S.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Byram, D.; Caldwell, A. S.; Chan, Y.-D.; Christofferson, C. D.; Combs, D. C.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu.; Egorov, V.; Ejiri, H.; Elliott, S. R.; Fast, J. E.; Finnerty, P.; Fraenkle, F. M.; Galindo-Uribarri, A.; Giovanetti, G. K.; Goett, J.; Green, M. P.; Gruszko, J.; Guiseppe, V. E.; Gusev, K.; Hallin, A. L.; Hazama, R.; Hegai, A.; Henning, R.; Hoppe, E. W.; Howard, S.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; Leon, J.; Leviner, L. E.; Loach, J. C.; MacMullin, J.; MacMullin, S.; Martin, R. D.; Meijer, S.; Mertens, S.; Nomachi, M.; Orrell, J. L.; O'Shaughnessy, C.; Overman, N. R.; Phillips, D. G.; Poon, A. W. P.; Pushkin, K.; Radford, D. C.; Rager, J.; Rielage, K.; Robertson, R. G. H.; Romero-Romero, E.; Ronquest, M. C.; Schubert, A. G.; Shanks, B.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Snyder, N.; Suriano, A. M.; Thompson, J.; Timkin, V.; Tornow, W.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Young, A. R.; Yu, C.-H.; Yumatov, V.

The Majorana Collaboration is constructing a system containing 40 kg of HPGe detectors to demonstrate the feasibility and potential of a future tonne-scale experiment capable of probing the neutrino mass scale in the inverted-hierarchy region. To realize this, a major goal of the Majorana Demonstrator is to demonstrate a path forward to achieving a background rate at or below 1 cnt/(ROI-t-y) in the 4 keV region of interest around the Q-value at 2039 keV. This goal is pursued through a combination of a significant reduction of radioactive impurities in construction materials with analytical methods for background rejection, for example using powerful pulse shape analysis techniques profiting from the p-type point contact HPGe detectors technology. The effectiveness of these methods is assessed using simulations of the different background components whose purity levels are constrained from radioassay measurements.

Background model for the Majorana Demonstrator

DOE PAGES

Cuesta, C.; Abgrall, N.; Aguayo, E.; ...

2015-01-01

The Majorana Collaboration is constructing a system containing 40 kg of HPGe detectors to demonstrate the feasibility and potential of a future tonne-scale experiment capable of probing the neutrino mass scale in the inverted-hierarchy region. To realize this, a major goal of the Majorana Demonstrator is to demonstrate a path forward to achieving a background rate at or below 1 cnt/(ROI-t-y) in the 4 keV region of interest around the Q-value at 2039 keV. This goal is pursued through a combination of a significant reduction of radioactive impurities in construction materials with analytical methods for background rejection, for example usingmore » powerful pulse shape analysis techniques profiting from the p-type point contact HPGe detectors technology. The effectiveness of these methods is assessed using simulations of the different background components whose purity levels are constrained from radioassay measurements.« less

Background Lamb waves in the Earth's atmosphere

NASA Astrophysics Data System (ADS)

Nishida, K.; Kobayashi, N.; Fukao, Y.

2013-12-01

Lamb waves of the Earth's atmosphere in the millihertz band have been considered as transient phenomena excited only by large events [e.g. the major volcanic eruption of Krakatoa in 1833, the impact of Siberian meteorite in 1908, the testing of large nuclear tests and the huge earthquakes, Garrett1969]. In a case of the solid Earth, observation of background free oscillations in the millihertz band-now known as Earth's background free oscillations or seismic hum, has been firmly established. Above 5 mHz, their dominant excitation sources are oceanic infragravity waves. At 3.7 and 4.4 mHz an elasto-acoustic resonance between the solid Earth and the atmosphere was observed [Nishida et al., 2000]. These seismic observations show that the contribution of atmospheric disturbances to the seismic hum is dominant below 5 mHz. Such contribution implies background excitations of acoustic-gravity waves in this frequency range. For direct detection of the background acoustic-gravity waves, our group conducted observations using an array of barometers [Nishida et al. 2005]. However, the spatial scale of the array of about 10 km was too small to detect acoustic modes below 10 mHz. Since then, no direct observations of these waves have been reported. In 2011, 337 high-resolution microbarometers were installed on a continental scale at USArray Transportable Array. The large and dense array enables us to detect the background atmospheric waves. Here, we show the first evidence of background Lamb waves in the Earth's atmosphere from 0.2 to 10 mHz, based on the array analysis of microbarometer data from the USArray in 2012. The observations suggest that the excitation sources are atmospheric disturbances in the troposphere. Theoretically, their energy in the troposphere tunnels into the thermosphere at a resonant frequency via thermospheric gravity wave, where the observed amplitudes indeed take a local minimum. The energy leak through the frequency window could partly contribute to

Background Knowledge in Learning-Based Relation Extraction

ERIC Educational Resources Information Center

Do, Quang Xuan

2012-01-01

In this thesis, we study the importance of background knowledge in relation extraction systems. We not only demonstrate the benefits of leveraging background knowledge to improve the systems' performance but also propose a principled framework that allows one to effectively incorporate knowledge into statistical machine learning models for…

Judgments of aircraft noise in a traffic noise background

NASA Technical Reports Server (NTRS)

Powell, C. A.; Rice, C. G.

1975-01-01

An investigation was conducted to determine subjective response to aircraft noise in different road traffic backgrounds. In addition, two laboratory techniques for presenting the aircraft noise with the background noise were evaluated. For one technique, the background noise was continuous over an entire test session; for the other, the background noise level was changed with each aircraft noise during a session. Subjective response to aircraft noise was found to decrease with increasing background noise level, for a range of typical indoor noise levels. Subjective response was found to be highly correlated with the Noise Pollution Level (NPL) measurement scale.

Spatiotemporal models for the simulation of infrared backgrounds

NASA Astrophysics Data System (ADS)

Wilkes, Don M.; Cadzow, James A.; Peters, R. Alan, II; Li, Xingkang

1992-09-01

It is highly desirable for designers of automatic target recognizers (ATRs) to be able to test their algorithms on targets superimposed on a wide variety of background imagery. Background imagery in the infrared spectrum is expensive to gather from real sources, consequently, there is a need for accurate models for producing synthetic IR background imagery. We have developed a model for such imagery that will do the following: Given a real, infrared background image, generate another image, distinctly different from the one given, that has the same general visual characteristics as well as the first and second-order statistics of the original image. The proposed model consists of a finite impulse response (FIR) kernel convolved with an excitation function, and histogram modification applied to the final solution. A procedure for deriving the FIR kernel using a signal enhancement algorithm has been developed, and the histogram modification step is a simple memoryless nonlinear mapping that imposes the first order statistics of the original image onto the synthetic one, thus the overall model is a linear system cascaded with a memoryless nonlinearity. It has been found that the excitation function relates to the placement of features in the image, the FIR kernel controls the sharpness of the edges and the global spectrum of the image, and the histogram controls the basic coloration of the image. A drawback to this method of simulating IR backgrounds is that a database of actual background images must be collected in order to produce accurate FIR and histogram models. If this database must include images of all types of backgrounds obtained at all times of the day and all times of the year, the size of the database would be prohibitive. In this paper we propose improvements to the model described above that enable time-dependent modeling of the IR background. This approach can greatly reduce the number of actual IR backgrounds that are required to produce a

32 CFR 770.54 - Background.

Code of Federal Regulations, 2013 CFR

2013-07-01

... ACCESS TO PARTICULAR INSTALLATIONS Entry Regulations for Portsmouth Naval Shipyard, Portsmouth, New Hampshire § 770.54 Background. (a) Portsmouth Naval Shipyard maintains and operates facilities “to provide...

32 CFR 770.54 - Background.

Code of Federal Regulations, 2014 CFR

2014-07-01

... ACCESS TO PARTICULAR INSTALLATIONS Entry Regulations for Portsmouth Naval Shipyard, Portsmouth, New Hampshire § 770.54 Background. (a) Portsmouth Naval Shipyard maintains and operates facilities “to provide...

32 CFR 770.54 - Background.

Code of Federal Regulations, 2011 CFR

2011-07-01

... ACCESS TO PARTICULAR INSTALLATIONS Entry Regulations for Portsmouth Naval Shipyard, Portsmouth, New Hampshire § 770.54 Background. (a) Portsmouth Naval Shipyard maintains and operates facilities “to provide...

32 CFR 770.54 - Background.

Code of Federal Regulations, 2012 CFR

2012-07-01

... ACCESS TO PARTICULAR INSTALLATIONS Entry Regulations for Portsmouth Naval Shipyard, Portsmouth, New Hampshire § 770.54 Background. (a) Portsmouth Naval Shipyard maintains and operates facilities “to provide...

36 CFR 401.3 - Background.

Code of Federal Regulations, 2010 CFR

2010-07-01

... § 401.3 Background. Following World War I many American individuals, organizations and governmental... many issues including host nation approvals, design adequacy, and funding for perpetual maintenance. As...

Child Care: State Requirements for Background Checks.

ERIC Educational Resources Information Center

Fagnoni, Cynthia

Background checks involve gathering information from state and federal databases to determine if child care providers have a history of child abuse or other criminal convictions that would make them unacceptable for working with children. Background checks include state criminal history checks, state child abuse registry checks, and Federal Bureau…

The diffuse infrared background - COBE and other observations

NASA Technical Reports Server (NTRS)

Hauser, M. G.; Kelsall, T.; Moseley, S. H., Jr.; Silverberg, R. F.; Murdock, T.; Toller, G.; Spiesman, W.; Weiland, J.

1991-01-01

The Diffuse Infrared Background Experiment (DIRBE) on the Cosmic Background Explorer (COBE) satellite is designed to conduct a sensitive search for an isotropic cosmic infrared background radiation over the spectral range from 1 to 300 micrometers. The cumulative emissions of pregalactic, protogalactic, and evolving galactic systems are expected to be recorded in this background. The DIRBE instrument, a 10 spectral band absolute photometer with an 0.7 deg field of view, maps the full sky with high redundancy at solar elongation angles ranging from 64 to 124 degrees to facilitate separation of interplanetary, Galactic, and extragalactic sources of emission. Initial sky maps show the expected character of the foreground emissions, with relative minima at wavelengths of 3.4 micrometers and longward of 100 micrometers. Extensive modelling of the foregrounds, just beginning, will be required to isolate the extragalactic component. In this paper, we summarize the status of diffuse infrared background observations from the DIRBE, and compare preliminary results with those of recent rocket and satellite instruments.

Staffing Preschools: Background Information.

ERIC Educational Resources Information Center

Katz, Lilian G.; Weir, Mary K.

This report explores background variables related to preschool teaching, and emphasizes that statistics fluctuate in early childhood education. The increase for preprimary enrollment of 3- and 4-year-olds was 26 percent from 1966 to 1967. Accurate figures on preschool teaching personnel are not available, but a large proportion of Head Start…

Background Independence and Duality Invariance in String Theory.

PubMed

Hohm, Olaf

2017-03-31

Closed string theory exhibits an O(D,D) duality symmetry on tori, which in double field theory is manifest before compactification. I prove that to first order in α^{'} there is no manifestly background independent and duality invariant formulation of bosonic string theory in terms of a metric, b field, and dilaton. To this end I use O(D,D) invariant second order perturbation theory around flat space to show that the unique background independent candidate expression for the gauge algebra at order α^{'} is inconsistent with the Jacobi identity. A background independent formulation exists instead for frame variables subject to α^{'}-deformed frame transformations (generalized Green-Schwarz transformations). Potential applications for curved backgrounds, as in cosmology, are discussed.

An EPIC Tale of the Quiescent Particle Background

NASA Technical Reports Server (NTRS)

Snowden, S.L.; Kuntz, K.D.

2017-01-01

Extended Source Analysis Software Use Based Empirical Investigation: (1) Builds quiescent particle background (QPB) spectra and images for observations of extended sources that fill (or mostly fill) the FOV i.e., annular background subtraction won't work. (2) Uses a combination of Filter Wheel Closed (FWC) and corner data to capture the spectral, spatial, and temporal variation of the quiescent particle background. New Work: (1) Improved understanding of the QPB (aided by adding a whole lot of data since 2008). (2) Significantly improved statistics (did I mention a LOT more data?). (3) Better characterization and identification of anomalous states. (4) Builds backgrounds for some anomalous state. (5) New efficient method for non-anomalous states.

Cosmological origin of anomalous radio background

NASA Astrophysics Data System (ADS)

Cline, James M.; Vincent, Aaron C.

2013-02-01

The ARCADE 2 collaboration has reported a significant excess in the isotropic radio background, whose homogeneity cannot be reconciled with clustered sources. This suggests a cosmological origin prior to structure formation. We investigate several potential mechanisms and show that injection of relativistic electrons through late decays of a metastable particle can give rise to the observed excess radio spectrum through synchrotron emission. However, constraints from the cosmic microwave background (CMB) anisotropy, on injection of charged particles and on the primordial magnetic field, present a challenge. The simplest scenario is with a gtrsim9 GeV particle decaying into e+e- at a redshift of z ~ 5, in a magnetic field of ~ 5μG, which exceeds the CMB B-field constraints, unless the field was generated after decoupling. Decays into exotic millicharged particles can alleviate this tension, if they emit synchroton radiation in conjunction with a sufficiently large background magnetic field of a dark U(1)' gauge field.

Advanced Background Subtraction Applied to Aeroacoustic Wind Tunnel Testing

NASA Technical Reports Server (NTRS)

Bahr, Christopher J.; Horne, William C.

2015-01-01

An advanced form of background subtraction is presented and applied to aeroacoustic wind tunnel data. A variant of this method has seen use in other fields such as climatology and medical imaging. The technique, based on an eigenvalue decomposition of the background noise cross-spectral matrix, is robust against situations where isolated background auto-spectral levels are measured to be higher than levels of combined source and background signals. It also provides an alternate estimate of the cross-spectrum, which previously might have poor definition for low signal-to-noise ratio measurements. Simulated results indicate similar performance to conventional background subtraction when the subtracted spectra are weaker than the true contaminating background levels. Superior performance is observed when the subtracted spectra are stronger than the true contaminating background levels. Experimental results show limited success in recovering signal behavior for data where conventional background subtraction fails. They also demonstrate the new subtraction technique's ability to maintain a proper coherence relationship in the modified cross-spectral matrix. Beam-forming and de-convolution results indicate the method can successfully separate sources. Results also show a reduced need for the use of diagonal removal in phased array processing, at least for the limited data sets considered.

The Cosmic Infrared Background Experiment (CIBER): A Sounding Rocket Payload to Study the near Infrared Extragalactic Background Light

NASA Astrophysics Data System (ADS)

Zemcov, M.; Arai, T.; Battle, J.; Bock, J.; Cooray, A.; Hristov, V.; Keating, B.; Kim, M. G.; Lee, D. H.; Levenson, L. R.; Mason, P.; Matsumoto, T.; Matsuura, S.; Nam, U. W.; Renbarger, T.; Sullivan, I.; Suzuki, K.; Tsumura, K.; Wada, T.

2013-08-01

The Cosmic Infrared Background Experiment (CIBER) is a suite of four instruments designed to study the near infrared (IR) background light from above the Earth's atmosphere. The instrument package comprises two imaging telescopes designed to characterize spatial anisotropy in the extragalactic IR background caused by cosmological structure during the epoch of reionization, a low resolution spectrometer to measure the absolute spectrum of the extragalactic IR background, and a narrow band spectrometer optimized to measure the absolute brightness of the zodiacal light foreground. In this paper we describe the design and characterization of the CIBER payload. The detailed mechanical, cryogenic, and electrical design of the system are presented, including all system components common to the four instruments. We present the methods and equipment used to characterize the instruments before and after flight, and give a detailed description of CIBER's flight profile and configurations. CIBER is designed to be recoverable and has flown four times, with modifications to the payload having been informed by analysis of the first flight data. All four instruments performed to specifications during the subsequent flights, and the scientific data from these flights are currently being analyzed.

THE COSMIC INFRARED BACKGROUND EXPERIMENT (CIBER): A SOUNDING ROCKET PAYLOAD TO STUDY THE NEAR INFRARED EXTRAGALACTIC BACKGROUND LIGHT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zemcov, M.; Bock, J.; Hristov, V.

2013-08-15

The Cosmic Infrared Background Experiment (CIBER) is a suite of four instruments designed to study the near infrared (IR) background light from above the Earth's atmosphere. The instrument package comprises two imaging telescopes designed to characterize spatial anisotropy in the extragalactic IR background caused by cosmological structure during the epoch of reionization, a low resolution spectrometer to measure the absolute spectrum of the extragalactic IR background, and a narrow band spectrometer optimized to measure the absolute brightness of the zodiacal light foreground. In this paper we describe the design and characterization of the CIBER payload. The detailed mechanical, cryogenic, andmore » electrical design of the system are presented, including all system components common to the four instruments. We present the methods and equipment used to characterize the instruments before and after flight, and give a detailed description of CIBER's flight profile and configurations. CIBER is designed to be recoverable and has flown four times, with modifications to the payload having been informed by analysis of the first flight data. All four instruments performed to specifications during the subsequent flights, and the scientific data from these flights are currently being analyzed.« less

Personal Background Knowledge Influences Cross-Cultural Understanding

ERIC Educational Resources Information Center

Lin, Xiaodong; Bransford, John D.

2010-01-01

Purpose of the Study: The purpose of the study was to investigate how two types of videos, personal background knowledge (PBK) and general background knowledge (GBK), affect people's interpretation of a classroom problem case that involved a disconnection between a foreign college professor and her students. The PBK video described the professor's…

Cosmic Microwave Background Timeline

Science.gov Websites

about 2.3 K 1948: George Gamow, Ralph Alpher, and Robert Herman predict that a Big Bang universe perfect blackbody spectrum and thereby strongly supporting the hot big bang model, the thermal history of anisotropy in the cosmic microwave background, this strongly supports the big bang model with gravitational

Bacteriological study of juvenile periodontitis in China.

PubMed

Han, N M; Xiao, X R; Zhang, L S; Ri, X Q; Zhang, J Z; Tong, Y H; Yang, M R; Xiao, Z R

1991-09-01

The predominant cultivable bacteria associated with juvenile periodontitis (JP) in China were studied for the first time. Subgingival plaque samples were taken on paper points from 23 diseased sites in 15 JP patients and from 7 healthy sites in 7 control subjects. Serially diluted plaque samples were plated on nonselective blood agar and on MGB agar, a selective medium for the isolation of Actinobacillus actinomycetemcomitans. Fifteen or more isolated colonies from each sample (in sequence without selection) were purified for identification. The results indicated that the microflora in healthy sulci of the 7 control subjects was significantly different from that in diseased sites of JP patients. The predominant species in healthy sulci were Streptococcus spp. and Capnocytophaga gingivalis. In JP patients, Eubacterium sp. was found in significantly higher frequency and proportion. Actinobacillus actinomycetemcomitans was not detected in any samples. It appears that this species is not associated with juvenile periodontitis in China.

getimages: Background derivation and image flattening method

NASA Astrophysics Data System (ADS)

Men'shchikov, Alexander

2017-05-01

getimages performs background derivation and image flattening for high-resolution images obtained with space observatories. It is based on median filtering with sliding windows corresponding to a range of spatial scales from the observational beam size up to a maximum structure width X. The latter is a single free parameter of getimages that can be evaluated manually from the observed image. The median filtering algorithm provides a background image for structures of all widths below X. The same median filtering procedure applied to an image of standard deviations derived from a background-subtracted image results in a flattening image. Finally, a flattened image is computed by dividing the background-subtracted by the flattening image. Standard deviations in the flattened image are now uniform outside sources and filaments. Detecting structures in such radically simplified images results in much cleaner extractions that are more complete and reliable. getimages also reduces various observational and map-making artifacts and equalizes noise levels between independent tiles of mosaicked images. The code (a Bash script) uses FORTRAN utilities from getsources (ascl:1507.014), which must be installed.

The Anisotropy of the Microwave Background to l = 3500: Deep Field Observations with the Cosmic Background Imager

NASA Technical Reports Server (NTRS)

Mason, B. S.; Pearson, T. J.; Readhead, A. C. S.; Shepherd, M. C.; Sievers, J.; Udomprasert, P. S.; Cartwright, J. K.; Farmer, A. J.; Padin, S.; Myers, S. T.;

32 CFR 770.37 - Background.

Code of Federal Regulations, 2010 CFR

2010-07-01

... ACCESS TO PARTICULAR INSTALLATIONS Entry Regulations for Naval Installations and Property in Puerto Rico § 770.37 Background. In accordance with 32 CFR 765.4, Naval installations and properties in Puerto Rico...

32 CFR 770.37 - Background.

Code of Federal Regulations, 2011 CFR

2011-07-01

... ACCESS TO PARTICULAR INSTALLATIONS Entry Regulations for Naval Installations and Property in Puerto Rico § 770.37 Background. In accordance with 32 CFR 765.4, Naval installations and properties in Puerto Rico...

Background feature descriptor for offline handwritten numeral recognition

NASA Astrophysics Data System (ADS)

Ming, Delie; Wang, Hao; Tian, Tian; Jie, Feiran; Lei, Bo

2011-11-01

This paper puts forward an offline handwritten numeral recognition method based on background structural descriptor (sixteen-value numerical background expression). Through encoding the background pixels in the image according to a certain rule, 16 different eigenvalues were generated, which reflected the background condition of every digit, then reflected the structural features of the digits. Through pattern language description of images by these features, automatic segmentation of overlapping digits and numeral recognition can be realized. This method is characterized by great deformation resistant ability, high recognition speed and easy realization. Finally, the experimental results and conclusions are presented. The experimental results of recognizing datasets from various practical application fields reflect that with this method, a good recognition effect can be achieved.

Background rejection in NEXT using deep neural networks

DOE PAGES

Renner, J.; Farbin, A.; Vidal, J. Muñoz; ...

2017-01-16

Here, we investigate the potential of using deep learning techniques to reject background events in searches for neutrinoless double beta decay with high pressure xenon time projection chambers capable of detailed track reconstruction. The differences in the topological signatures of background and signal events can be learned by deep neural networks via training over many thousands of events. These networks can then be used to classify further events as signal or background, providing an additional background rejection factor at an acceptable loss of efficiency. The networks trained in this study performed better than previous methods developed based on the usemore » of the same topological signatures by a factor of 1.2 to 1.6, and there is potential for further improvement.« less

Study of Background Rejection Systems for the IXO Mission.

NASA Astrophysics Data System (ADS)

Laurent, Philippe; Limousin, O.; Tatischeff, V.

2009-01-01

The scientific performances of the IXO mission will necessitate a very low detector background level. This will imply thorough background simulations, and efficient background rejection systems. It necessitates also a very good knowledge of the detectors to be shielded. In APC, Paris, and CEA, Saclay, we got experience on these activities by conceiving and optimising in parallel the high energy detector and the active and passive background rejection system of the Simbol-X mission. Considering that this work may be naturally extended to other X-ray missions, we have initiated with CNES a R&D project on the study of background rejection systems mainly in view the IXO project. We will detail this activity in the poster.

COBE - Cosmic Background Explorer

Science.gov Websites

with that from a precise blackbody. Data from the full four years of COBE observations continue to be stages in the COBE project. DIRBE (Diffuse Infrared Background Experiment) DIRBE has mapped the absolute sky brightness in 10 wavelength bands ranging from 1.25 microns to 240 microns. These data contain the

40 CFR 1065.667 - Dilution air background emission correction.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.667 Dilution air background emission correction. (a) To determine the mass of background emissions to subtract... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Dilution air background emission...

40 CFR 1065.667 - Dilution air background emission correction.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.667 Dilution air background emission correction. (a) To determine the mass of background emissions to subtract... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Dilution air background emission...

40 CFR 1065.667 - Dilution air background emission correction.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.667 Dilution air background emission correction. (a) To determine the mass of background emissions to subtract... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Dilution air background emission...

40 CFR 1065.667 - Dilution air background emission correction.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.667 Dilution air background emission correction. (a) To determine the mass of background emissions to subtract... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Dilution air background emission...

40 CFR 1065.667 - Dilution air background emission correction.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.667 Dilution air background emission correction. (a) To determine the mass of background emissions to subtract... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Dilution air background emission...

32 CFR 770.49 - Background.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., Washington § 770.49 Background. (a) Puget Sound Naval Shipyard is a major naval ship repair facility, with... interruption. Additionally, most of Puget Sound Naval Shipyard is dedicated to heavy industrial activity where...

Activity patterns in networks stabilized by background oscillations.

PubMed

Hoppensteadt, Frank

2009-07-01

The brain operates in a highly oscillatory environment. We investigate here how such an oscillating background can create stable organized behavior in an array of neuro-oscillators that is not observable in the absence of oscillation, much like oscillating the support point of an inverted pendulum can stabilize its up position, which is unstable without the oscillation. We test this idea in an array of electronic circuits coming from neuroengineering: we show how the frequencies of the background oscillation create a partition of the state space into distinct basins of attraction. Thus, background signals can stabilize persistent activity that is otherwise not observable. This suggests that an image, represented as a stable firing pattern which is triggered by a voltage pulse and is sustained in synchrony or resonance with the background oscillation, can persist as a stable behavior long after the initial stimulus is removed. The background oscillations provide energy for organized behavior in the array, and these behaviors are categorized by the basins of attraction determined by the oscillation frequencies.

Radon-related Backgrounds in the LUX Dark Matter Search

NASA Astrophysics Data System (ADS)

Bradley, A.; Akerib, D. S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Bernard, E.; Bernstein, A.; Byram, D.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chapman, J. J.; Chiller, A. A.; Chiller, C.; Coffey, T.; Currie, A.; de Viveiros, L.; Dobi, A.; Dobson, J.; Druszkiewicz, E.; Edwards, B.; Faham, C. H.; Fiorucci, S.; Flores, C.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G. D.; Hall, C.; Hertel, S. A.; Horn, M.; Huang, D. Q.; Ihm, M.; Jacobsen, R. G.; Kazkaz, K.; Knoche, R.; Larsen, N. A.; Lee, C.; Lindote, A.; Lopes, M. I.; Malling, D. C.; Mannino, R.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H.; Neves, F.; Ott, R. A.; Pangilinan, M.; Parker, P. D.; Pease, E. K.; Pech, K.; Phelps, P.; Reichhart, L.; Shutt, T.; Silva, C.; Solovov, V. N.; Sorensen, P.; O'Sullivan, K.; Sumner, T. J.; Szydagis, M.; Taylor, D.; Tennyson, B.; Tiedt, D. R.; Tripathi, M.; Uvarov, S.; Verbus, J. R.; Walsh, N.; Webb, R.; White, J. T.; Witherell, M. S.; Wolfs, F. L. H.; Woods, M.; Zhang, C.

The LUX detector is currently in operation at the Davis Campus at the 4850' level of the Sanford Underground Research Facility (SURF) in Lead, SD to directly search for WIMP dark matter. Knowing the type and rate of backgrounds is critical in a rare, low energy event search, and LUX was designed, constructed, and deployed to mitigate backgrounds, both internal and external. An important internal background are decays of radon and its daughters. These consist of alpha decays, which are easily tagged and are a tracer of certain backgrounds, and beta decays, some of which are not as readily tagged and present a background for the WIMP search. We report on studies of alpha decay and discuss implications for the WIMP search.

Study of the GERDA Phase II background spectrum

NASA Astrophysics Data System (ADS)

Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; Di Marco, N.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Salathe, M.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schulz, O.; Schütz, A.-K.; Schwingenheuer, B.; Selivanenko, O.; Shevzik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

2017-09-01

The Gerda experiment, located at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN in Italy, searches for the neutrinoless double beta (0νββ) decay of 76Ge. Gerda Phase II is aiming to reach a sensitivity for the 0νββ half life of 1026 yr in ˜ 3 years of physics data taking with 100 kg·yr of exposure and a background index of ˜ 10-3 cts/(keV·kg·yr). After 6 months of acquisition a first data release with 10.8 kg·yr of exposure is performed, showing that the design background is achieved. In this work a study of the Phase II background spectrum, the main spectral structures and the background sources will be presented and discussed.

Simulation of PEP-II Accelerator Backgrounds Using TURTLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barlow, R.J.; Fieguth, T.; /SLAC

2006-02-15

We present studies of accelerator-induced backgrounds in the BaBar detector at the SLAC B-Factory, carried out using LPTURTLE, a modified version of the DECAY TURTLE simulation package. Lost-particle backgrounds in PEP-II are dominated by a combination of beam-gas bremstrahlung, beam-gas Coulomb scattering, radiative-Bhabha events and beam-beam blow-up. The radiation damage and detector occupancy caused by the associated electromagnetic shower debris can limit the usable luminosity. In order to understand and mitigate such backgrounds, we have performed a full program of beam-gas and luminosity-background simulations, that include the effects of the detector solenoidal field, detailed modeling of limiting apertures in bothmore » collider rings, and optimization of the betatron collimation scheme in the presence of large transverse tails.« less

Olfactory cortical adaptation facilitates detection of odors against background.

PubMed

Kadohisa, Mikiko; Wilson, Donald A

2006-03-01

Detection and discrimination of odors generally, if not always, occurs against an odorous background. On any given inhalation, olfactory receptor neurons will be activated by features of both the target odorant and features of background stimuli. To identify a target odorant against a background therefore, the olfactory system must be capable of grouping a subset of features into an odor object distinct from the background. Our previous work has suggested that rapid homosynaptic depression of afferents to the anterior piriform cortex (aPCX) contributes to both cortical odor adaptation to prolonged stimulation and habituation of simple odor-evoked behaviors. We hypothesize here that this process may also contribute to figure-ground separation of a target odorant from background stimulation. Single-unit recordings were made from both mitral/tufted cells and aPCX neurons in urethan-anesthetized rats and mice. Single-unit responses to odorant stimuli and their binary mixtures were determined. One of the odorants was randomly selected as the background and presented for 50 s. Forty seconds after the onset of the background stimulus, the second target odorant was presented, producing a binary mixture. The results suggest that mitral/tufted cells continue to respond to the background odorant and, when the target odorant is presented, had response magnitudes similar to that evoked by the binary mixture. In contrast, aPCX neurons filter out the background stimulus while maintaining responses to the target stimulus. Thus the aPCX acts as a filter driven most strongly by changing stimuli, providing a potential mechanism for olfactory figure-ground separation and selective reading of olfactory bulb output.

Background levels in the Borexino detector

NASA Astrophysics Data System (ADS)

D'Angelo, Davide; Wurm, Michael; Borexino Collaboration

2008-11-01

The Borexino detector, designed and constructed for sub-MeV solar neutrino spectroscopy, is taking data at the Gran Sasso Laboratory, Italy; since May 2007. The main physics objective of Borexino, based on elastic scattering of neutrinos in organic liquid scintillator, is the real time flux measurement of the 862keV mono-energetic neutrinos from 7Be, which set extremely severe radio-purity requirements in the detector's design and handling. The first year of continous data taking provide now evidence of the extremely low background levels achieved in the construction of the detector and in the purification of the target mass. Several pieces of analysis sense the presence of radioisotopes of the 238U and 232Th chains, of 85Kr and of 210Po out of equilibrium from other Radon daughters. Particular emphasis is given to the detection of the cosmic muon background whose angular distributions have been obtained with the outer detector tracking algorithm and to the possibility of tagging the muon-induced neutron background in the scintillator with the recently enhanced electronics setup.

Background Model for the Majorana Demonstrator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cuesta, C.; Abgrall, N.; Aguayo, Estanislao

2015-06-01

The Majorana Collaboration is constructing a prototype system containing 40 kg of HPGe detectors to demonstrate the feasibility and potential of a future tonne-scale experiment to search for neutrinoless double-beta (0v BB) decay in 76Ge. In view of the requirement that the next generation of tonne-scale Ge-based 0vBB-decay experiment be capable of probing the neutrino mass scale in the inverted-hierarchy region, a major goal of theMajorana Demonstrator is to demonstrate a path forward to achieving a background rate at or below 1 cnt/(ROI-t-y) in the 4 keV region of interest around the Q-value at 2039 keV. This goal is pursuedmore » through a combination of a significant reduction of radioactive impurities in construction materials with analytical methods for background rejection, for example using powerful pulse shape analysis techniques profiting from the p-type point contact HPGe detectors technology. The effectiveness of these methods is assessed using Geant4 simulations of the different background components whose purity levels are constrained from radioassay measurements.« less

Cultural background shapes spatial reference frame proclivity

PubMed Central

Goeke, Caspar; Kornpetpanee, Suchada; Köster, Moritz; Fernández-Revelles, Andrés B.; Gramann, Klaus; König, Peter

2015-01-01

Spatial navigation is an essential human skill that is influenced by several factors. The present study investigates how gender, age, and cultural background account for differences in reference frame proclivity and performance in a virtual navigation task. Using an online navigation study, we recorded reaction times, error rates (confusion of turning axis), and reference frame proclivity (egocentric vs. allocentric reference frame) of 1823 participants. Reaction times significantly varied with gender and age, but were only marginally influenced by the cultural background of participants. Error rates were in line with these results and exhibited a significant influence of gender and culture, but not age. Participants’ cultural background significantly influenced reference frame selection; the majority of North-Americans preferred an allocentric strategy, while Latin-Americans preferred an egocentric navigation strategy. European and Asian groups were in between these two extremes. Neither the factor of age nor the factor of gender had a direct impact on participants’ navigation strategies. The strong effects of cultural background on navigation strategies without the influence of gender or age underlines the importance of socialized spatial cognitive processes and argues for socio-economic analysis in studies investigating human navigation. PMID:26073656

Chandra ACIS-I particle background: an analytical model

NASA Astrophysics Data System (ADS)

Bartalucci, I.; Mazzotta, P.; Bourdin, H.; Vikhlinin, A.

2014-06-01

Aims: Imaging and spectroscopy of X-ray extended sources require a proper characterisation of a spatially unresolved background signal. This background includes sky and instrumental components, each of which are characterised by its proper spatial and spectral behaviour. While the X-ray sky background has been extensively studied in previous work, here we analyse and model the instrumental background of the ACIS-I detector on board the Chandra X-ray observatory in very faint mode. Methods: Caused by interaction of highly energetic particles with the detector, the ACIS-I instrumental background is spectrally characterised by the superimposition of several fluorescence emission lines onto a continuum. To isolate its flux from any sky component, we fitted an analytical model of the continuum to observations performed in very faint mode with the detector in the stowed position shielded from the sky, and gathered over the eight-year period starting in 2001. The remaining emission lines were fitted to blank-sky observations of the same period. We found 11 emission lines. Analysing the spatial variation of the amplitude, energy and width of these lines has further allowed us to infer that three lines of these are presumably due to an energy correction artefact produced in the frame store. Results: We provide an analytical model that predicts the instrumental background with a precision of 2% in the continuum and 5% in the lines. We use this model to measure the flux of the unresolved cosmic X-ray background in the Chandra deep field south. We obtain a flux of 10.2+0.5-0.4 × 10-13 erg cm-2 deg-2 s-1 for the [1-2] keV band and (3.8 ± 0.2) × 10-12 erg cm-2 deg-2 s-1 for the [2-8] keV band.

Radon-related backgrounds in the LUX dark matter search

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bradley, A.; Akerib, D. S.; Araújo, H. M.

The LUX detector is currently in operation at the Davis Campus at the 4850’ level of the Sanford Underground Research Facility (SURF) in Lead, SD to directly search for WIMP dark matter. Knowing the type and rate of backgrounds is critical in a rare, low energy event search, and LUX was designed, constructed, and deployed to mitigate backgrounds, both internal and external. An important internal background are decays of radon and its daughters. These consist of alpha decays, which are easily tagged and are a tracer of certain backgrounds, and beta decays, some of which are not as readily taggedmore » and present a background for the WIMP search. We report on studies of alpha decay and discuss implications for the WIMP search.« less

Radon-related backgrounds in the LUX dark matter search

DOE PAGES

Bradley, A.; Akerib, D. S.; Araújo, H. M.; ...

2015-01-01

The LUX detector is currently in operation at the Davis Campus at the 4850’ level of the Sanford Underground Research Facility (SURF) in Lead, SD to directly search for WIMP dark matter. Knowing the type and rate of backgrounds is critical in a rare, low energy event search, and LUX was designed, constructed, and deployed to mitigate backgrounds, both internal and external. An important internal background are decays of radon and its daughters. These consist of alpha decays, which are easily tagged and are a tracer of certain backgrounds, and beta decays, some of which are not as readily taggedmore » and present a background for the WIMP search. We report on studies of alpha decay and discuss implications for the WIMP search.« less

Why background colour matters to bees and flowers.

PubMed

Bukovac, Zoë; Shrestha, Mani; Garcia, Jair E; Burd, Martin; Dorin, Alan; Dyer, Adrian G

2017-05-01

Flowers are often viewed by bee pollinators against a variety of different backgrounds. On the Australian continent, backgrounds are very diverse and include surface examples of all major geological stages of the Earth's history, which have been present during the entire evolutionary period of Angiosperms. Flower signals in Australia are also representative of typical worldwide evolutionary spectral adaptations that enable successful pollination. We measured the spectral properties of 581 natural surfaces, including rocks, sand, green leaves, and dry plant materials, sampled from tropical Cairns through to the southern tip of mainland Australia. We modelled in a hexagon colour space, how interactions between background spectra and flower-like colour stimuli affect reliable discrimination and detection in bee pollinators. We calculated the extent to which a given locus would be conflated with the loci of a different flower-colour stimulus using empirically determined colour discrimination regions for bee vision. Our results reveal that whilst colour signals are robust in homogeneous background viewing conditions, there could be significant pressure on plant flowers to evolve saliently-different colours to overcome background spectral noise. We thus show that perceptual noise has a large influence on how colour information can be used in natural conditions.

Low-background Gamma Spectroscopy at Sanford Underground Laboratory

NASA Astrophysics Data System (ADS)

Chiller, Christopher; Alanson, Angela; Mei, Dongming

2014-03-01

Rare-event physics experiments require the use of material with unprecedented radio-purity. Low background counting assay capabilities and detectors are critical for determining the sensitivity of the planned ultra-low background experiments. A low-background counting, LBC, facility has been built at the 4850-Level Davis Campus of the Sanford Underground Research Facility to perform screening of material and detector parts. Like many rare event physics experiments, our LBC uses lead shielding to mitigate background radiation. Corrosion of lead brick shielding in subterranean installations creates radon plate-out potential as well as human risks of ingestible or respirable lead compounds. Our LBC facilities employ an exposed lead shield requiring clean smooth surfaces. A cleaning process of low-activity silica sand blasting and borated paraffin hot coating preservation was employed to guard against corrosion due to chemical and biological exposures. The resulting lead shield maintains low background contribution integrity while fully encapsulating the lead surface. We report the performance of the current LBC and a plan to develop a large germanium well detector for PMT screening. Support provided by Sd governors research center-CUBED, NSF PHY-0758120 and Sanford Lab.

Backgrounds and characteristics of arsonists.

PubMed

Labree, Wim; Nijman, Henk; van Marle, Hjalmar; Rassin, Eric

2010-01-01

The aim of this study was to gain more insight in the backgrounds and characteristics of arsonists. For this, the psychiatric, psychological, personal, and criminal backgrounds of all arsonists (n=25), sentenced to forced treatment in the maximum security forensic hospital "De Kijvelanden", were compared to the characteristics of a control group of patients (n=50), incarcerated at the same institution for other severe crimes. Apart from DSM-IV Axis I and Axis II disorders, family backgrounds, level of education, treatment history, intelligence (WAIS scores), and PCL-R scores were included in the comparisons. Furthermore, the apparent motives for the arson offences were explored. It was found that arsonists had more often received psychiatric treatment, prior to committing their index offence, and had a history of severe alcohol abuse more often in comparison to the controls. The arsonists turned out to be less likely to suffer from a major psychotic disorder. Both groups did not differ significantly on the other variables, among which the PCL-R total scores and factor scores. Exploratory analyses however, did suggest that arsonists may differentiate from non-arsonists on three items of the PCL-R, namely impulsivity (higher scores), superficial charm (lower scores), and juvenile delinquency (lower scores). Although the number of arsonists with a major psychotic disorder was relatively low (28%), delusional thinking of some form was judged to play a role in causing arson crimes in about half of the cases (52%).

Background radiation measurements at high power research reactors

DOE PAGES

Ashenfelter, J.; Yeh, M.; Balantekin, B.; ...

2015-10-23

Research reactors host a wide range of activities that make use of the intense neutron fluxes generated at these facilities. Recent interest in performing measurements with relatively low event rates, e.g. reactor antineutrino detection, at these facilities necessitates a detailed understanding of background radiation fields. Both reactor-correlated and naturally occurring background sources are potentially important, even at levels well below those of importance for typical activities. Here we describe a comprehensive series of background assessments at three high-power research reactors, including γ-ray, neutron, and muon measurements. For each facility we describe the characteristics and identify the sources of the backgroundmore » fields encountered. Furthermore, the general understanding gained of background production mechanisms and their relationship to facility features will prove valuable for the planning of any sensitive measurement conducted therein.« less

Modeling surface backgrounds from radon progeny plate-out

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perumpilly, G.; Guiseppe, V. E.; Snyder, N.

2013-08-08

The next generation low-background detectors operating deep underground aim for unprecedented low levels of radioactive backgrounds. The surface deposition and subsequent implantation of radon progeny in detector materials will be a source of energetic background events. We investigate Monte Carlo and model-based simulations to understand the surface implantation profile of radon progeny. Depending on the material and region of interest of a rare event search, these partial energy depositions can be problematic. Motivated by the use of Ge crystals for the detection of neutrinoless double-beta decay, we wish to understand the detector response of surface backgrounds from radon progeny. Wemore » look at the simulation of surface decays using a validated implantation distribution based on nuclear recoils and a realistic surface texture. Results of the simulations and measured α spectra are presented.« less

Enhancements to the MCNP6 background source

DOE PAGES

McMath, Garrett E.; McKinney, Gregg W.

2015-10-19

The particle transport code MCNP has been used to produce a background radiation data file on a worldwide grid that can easily be sampled as a source in the code. Location-dependent cosmic showers were modeled by Monte Carlo methods to produce the resulting neutron and photon background flux at 2054 locations around Earth. An improved galactic-cosmic-ray feature was used to model the source term as well as data from multiple sources to model the transport environment through atmosphere, soil, and seawater. A new elevation scaling feature was also added to the code to increase the accuracy of the cosmic neutronmore » background for user locations with off-grid elevations. Furthermore, benchmarking has shown the neutron integral flux values to be within experimental error.« less

Background compensation for a radiation level monitor

DOEpatents

Keefe, D.J.

1975-12-01

Background compensation in a device such as a hand and foot monitor is provided by digital means using a scaler. With no radiation level test initiated, a scaler is down-counted from zero according to the background measured. With a radiation level test initiated, the scaler is up-counted from the previous down-count position according to the radiation emitted from the monitored object and an alarm is generated if, with the scaler having crossed zero in the positive going direction, a particular number is exceeded in a specific time period after initiation of the test. If the test is initiated while the scale is down-counting, the background count from the previous down- count stored in a memory is used as the initial starting point for the up-count.

40 CFR 761.360 - Background.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Background. 761.360 Section 761.360 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT POLYCHLORINATED BIPHENYLS (PCBs) MANUFACTURING, PROCESSING, DISTRIBUTION IN COMMERCE, AND USE PROHIBITIONS Double...

Standard Model Background of the Cosmological Collider.

PubMed

Chen, Xingang; Wang, Yi; Xianyu, Zhong-Zhi

2017-06-30

The inflationary universe can be viewed as a "cosmological collider" with an energy of the Hubble scale, producing very massive particles and recording their characteristic signals in primordial non-Gaussianities. To utilize this collider to explore any new physics at very high scales, it is a prerequisite to understand the background signals from the particle physics standard model. In this Letter we describe the standard model background of the cosmological collider.

Reducing DRIFT backgrounds with a submicron aluminized-mylar cathode

NASA Astrophysics Data System (ADS)

Battat, J. B. R.; Daw, E.; Dorofeev, A.; Ezeribe, A. C.; Fox, J. R.; Gauvreau, J.-L.; Gold, M.; Harmon, L.; Harton, J.; Lafler, R.; Landers, J.; Lauer, R. J.; Lee, E. R.; Loomba, D.; Lumnah, A.; Matthews, J.; Miller, E. H.; Mouton, F.; Murphy, A. St. J.; Paling, S. M.; Phan, N.; Sadler, S. W.; Scarff, A.; Schuckman, F. G.; Snowden-Ifft, D.; Spooner, N. J. C.; Walker, D.

2015-09-01

Background events in the DRIFT-IId dark matter detector, mimicking potential WIMP signals, are predominantly caused by alpha decays on the central cathode in which the alpha particle is completely or partially absorbed by the cathode material. We installed a 0.9 μm thick aluminized-mylar cathode as a way to reduce the probability of producing these backgrounds. We study three generations of cathode (wire, thin-film, and radiologically clean thin-film) with a focus on the ratio of background events to alpha decays. Two independent methods of measuring the absolute alpha decay rate are used to ensure an accurate result, and agree to within 10%. Using alpha range spectroscopy, we measure the radiologically cleanest cathode version to have a contamination of 3.3±0.1 ppt 234U and 73±2 ppb 238U. This cathode reduces the probability of producing an RPR from an alpha decay by a factor of 70±20 compared to the original stainless steel wire cathode. First results are presented from a texturized version of the cathode, intended to be even more transparent to alpha particles. These efforts, along with other background reduction measures, have resulted in a drop in the observed background rate from 500/day to 1/day. With the recent implementation of full-volume fiducialization, these remaining background events are identified, allowing for background-free operation.

Removing Background Noise with Phased Array Signal Processing

NASA Technical Reports Server (NTRS)

Podboy, Gary; Stephens, David

2015-01-01

Preliminary results are presented from a test conducted to determine how well microphone phased array processing software could pull an acoustic signal out of background noise. The array consisted of 24 microphones in an aerodynamic fairing designed to be mounted in-flow. The processing was conducted using Functional Beam forming software developed by Optinav combined with cross spectral matrix subtraction. The test was conducted in the free-jet of the Nozzle Acoustic Test Rig at NASA GRC. The background noise was produced by the interaction of the free-jet flow with the solid surfaces in the flow. The acoustic signals were produced by acoustic drivers. The results show that the phased array processing was able to pull the acoustic signal out of the background noise provided the signal was no more than 20 dB below the background noise level measured using a conventional single microphone equipped with an aerodynamic forebody.

Raman background photobleaching as a possible method of cancer diagnostics

NASA Astrophysics Data System (ADS)

Brandt, Nikolai N.; Brandt, Nikolai B.; Chikishev, Andrey Y.; Gangardt, Mihail G.; Karyakina, Nina F.

2001-06-01

Kinetics of photobleaching of background in Raman spectra of aqueous solutions of plant toxins ricin and ricin agglutinin, ricin binding subunit, and normal and malignant human blood serum were measured. For the excitation of the spectra cw and pulsed laser radiation were used. The spectra of Raman background change upon laser irradiation. Background intensity is lower for the samples with small molecular weight. The cyclization of amino acid residues in the toxin molecules as well as in human blood serum can be a reason of the Raman background. The model of the background photobleaching is proposed. The differences in photobleaching kinetics in the cases of cw and pulsed laser radiation are discussed. It is shown that Raman background photobleaching can be very informative for cancer diagnostics.

The projected background for the CUORE experiment

DOE PAGES

Alduino, C.; Alfonso, K.; Artusa, D. R.; ...

2017-08-14

The Cryogenic Underground Observatory for Rare Events (CUORE) is designed to search for neutrinoless double beta decay of 130Te with an array of 988 TeO 2 bolometers operating at temperatures around 10 mK. The experiment is currently being commissioned in Hall A of Laboratori Nazionali del Gran Sasso, Italy. The goal of CUORE is to reach a 90% C.L. exclusion sensitivity on the 130Te decay half-life of 9 × 10 25 years after 5 years of data taking. The main issue to be addressed to accomplish this aim is the rate of background events in the region of interest, whichmore » must not be higher than 10 –2 counts/keV/kg/year. We developed a detailed Monte Carlo simulation, based on results from a campaign of material screening, radioassays, and bolometric measurements, to evaluate the expected background. This was used over the years to guide the construction strategies of the experiment and we use it here to project a background model for CUORE. In this paper we report the results of our study and our expectations for the background rate in the energy region where the peak signature of neutrinoless double beta decay of 130Te is expected.« less

The projected background for the CUORE experiment

NASA Astrophysics Data System (ADS)

Alduino, C.; Alfonso, K.; Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Banks, T. I.; Bari, G.; Beeman, J. W.; Bellini, F.; Benato, G.; Bersani, A.; Biassoni, M.; Branca, A.; Brofferio, C.; Bucci, C.; Camacho, A.; Caminata, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Cappelli, L.; Carbone, L.; Cardani, L.; Carniti, P.; Casali, N.; Cassina, L.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Cushman, J. S.; D'Addabbo, A.; Dafinei, I.; Davis, C. J.; Dell'Oro, S.; Deninno, M. M.; Di Domizio, S.; Di Vacri, M. L.; Drobizhev, A.; Fang, D. Q.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Gladstone, L.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Hansen, E.; Heeger, K. M.; Hennings-Yeomans, R.; Hickerson, K. P.; Huang, H. Z.; Kadel, R.; Keppel, G.; Kolomensky, Yu. G.; Leder, A.; Ligi, C.; Lim, K. E.; Ma, Y. G.; Maino, M.; Marini, L.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Mosteiro, P. J.; Napolitano, T.; Nastasi, M.; Nones, C.; Norman, E. B.; Novati, V.; Nucciotti, A.; O'Donnell, T.; Ouellet, J. L.; Pagliarone, C. E.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pira, C.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sakai, M.; Sangiorgio, S.; Santone, D.; Schmidt, B.; Schmidt, J.; Scielzo, N. D.; Singh, V.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tomei, C.; Trentalange, S.; Vignati, M.; Wagaarachchi, S. L.; Wang, B. S.; Wang, H. W.; Welliver, B.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zhang, G. Q.; Zhu, B. X.; Zimmermann, S.; Zucchelli, S.; Laubenstein, M.

2017-08-01

The Cryogenic Underground Observatory for Rare Events (CUORE) is designed to search for neutrinoless double beta decay of ^{130}Te with an array of 988 TeO_2 bolometers operating at temperatures around 10 mK. The experiment is currently being commissioned in Hall A of Laboratori Nazionali del Gran Sasso, Italy. The goal of CUORE is to reach a 90% C.L. exclusion sensitivity on the ^{130}Te decay half-life of 9 × 10^{25} years after 5 years of data taking. The main issue to be addressed to accomplish this aim is the rate of background events in the region of interest, which must not be higher than 10^{-2} counts/keV/kg/year. We developed a detailed Monte Carlo simulation, based on results from a campaign of material screening, radioassays, and bolometric measurements, to evaluate the expected background. This was used over the years to guide the construction strategies of the experiment and we use it here to project a background model for CUORE. In this paper we report the results of our study and our expectations for the background rate in the energy region where the peak signature of neutrinoless double beta decay of ^{130}Te is expected.