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Sample records for lethal phage pinhole

  1. Lethal effects of 32P decay on transfecting activity of Bacillus subtillis phage phie DNA

    International Nuclear Information System (INIS)

    Loveday, K.S.

    1979-01-01

    Disintegration of 32 P present in the DNA of Bacillus subtilis phage phie (a phage containing double-strand DNA) results in the loss of viability of intact phage as well as transfecting activity of isolated DNA. Only 1/12 of the 32 P disintegrations per phage DNA equivalent inactivities the intact phage while nearly every disintegration inactivates the transfecting DNA. This result provides evidence for a single-strand intermediate in the transfection of B. subtilis by phie DNA

  2. The role of the HCR system in the repair of lethal lesions of Bacillus subtilis phages and their transfecting DNA damaged by radiation and alkylating agents

    International Nuclear Information System (INIS)

    Vizdalova, M.; Janovska, E.; Zhestyanikov, V.D.

    1980-01-01

    The role of the HCR system in the repair of prelethal lesions induced by UV light, γ radiation and alkylating agents was studied in the Bacillus subtilis SPP1 phage, its heat sensitive mutants (N3, N73 nad ts 1 ) and corresponding infectious DNA. The survival of phages and their transfecting DNA after treatment with UV light is substantially higher in hcr + cells than in hcr cells, the differences being more striking in intact phages than in their transfecting DNA's. Repair inhibitors reduce survival in hcr + cells: caffeine lowers the survival of UV-irradiated phage SPP1 in exponentially growing hcr + cells but has no effect on its survival in competent hcr + cells; acriflavin and ethidium bromide decrease the survival of the UV-irradiated SPP1 phage in both exponentially growing and competent hcr + cells to the level of survival observed in hcr cells; moreover, ethidium bromide lowers the number of infective centres in hcr + cells of the UV-irradiated DNA of the SPP1 phage. Repair inhibitors do not lower the survival of the UV-irradiated phages or their DNA in hcr cells. The repair mechanism under study also effectively repairs lesions induced by polyfunctional alkylating agents in the transfecting DNA's of B. subtilis phages but is not functional with lesions induced by these agents in free phages and lesions caused in the phages and their DNA by ethyl methanesulphonate or γ radiation. (author)

  3. Graphic design of pinhole cameras

    Science.gov (United States)

    Edwards, H. B.; Chu, W. P.

    1979-01-01

    The paper describes a graphic technique for the analysis and optimization of pinhole size and focal length. The technique is based on the use of the transfer function of optical elements described by Scott (1959) to construct the transfer function of a circular pinhole camera. This transfer function is the response of a component or system to a pattern of lines having a sinusoidally varying radiance at varying spatial frequencies. Some specific examples of graphic design are presented.

  4. Virtual pinhole confocal microscope

    Energy Technology Data Exchange (ETDEWEB)

    George, J.S.; Rector, D.M.; Ranken, D.M. [Los Alamos National Lab., NM (United States). Biophysics Group; Peterson, B. [SciLearn Inc. (United States); Kesteron, J. [VayTech Inc. (United States)

    1999-06-01

    Scanned confocal microscopes enhance imaging capabilities, providing improved contrast and image resolution in 3-D, but existing systems have significant technical shortcomings and are expensive. Researchers at Los Alamos National Laboratory have developed a novel approach--virtual pinhole confocal microscopy--that uses state of the art illumination, detection, and data processing technologies to produce an imager with a number of advantages: reduced cost, faster imaging, improved efficiency and sensitivity, improved reliability and much greater flexibility. Work at Los Alamos demonstrated proof of principle; prototype hardware and software have been used to demonstrate technical feasibility of several implementation strategies. The system uses high performance illumination, patterned in time and space. The authors have built functional confocal imagers using video display technologies (LCD or DLP) and novel scanner based on a micro-lens array. They have developed a prototype system for high performance data acquisition and processing, designed to support realtime confocal imaging. They have developed algorithms to reconstruct confocal images from a time series of spatially sub-sampled images; software development remains an area of active development. These advances allow the collection of high quality confocal images (in fluorescence, reflectance and transmission modes) with equipment that can inexpensively retrofit to existing microscopes. Planned future extensions to these technologies will significantly enhance capabilities for microscopic imaging in a variety of applications, including confocal endoscopy, and confocal spectral imaging.

  5. From Pinholes to Black Holes

    Energy Technology Data Exchange (ETDEWEB)

    Fenimore, Edward E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-10-06

    Pinhole photography has made major contributions to astrophysics through the use of “coded apertures”. Coded apertures were instrumental in locating gamma-ray bursts and proving that they originate in faraway galaxies, some from the birth of black holes from the first stars that formed just after the big bang.

  6. Effect of pinhole shape on projection resolution

    International Nuclear Information System (INIS)

    Johnson, L C; Metzler, S D; Moore, S C

    2016-01-01

    We are designing a dual-resolution pre-clinical SPECT system based on square-pinhole apertures for use in applications with a small field-of-view (FOV), such as cardiac imaging of mice. Square pinholes allow for increased sensitivity due to more efficient projection tiling on the detector compared to circular pinholes. Aperture fabrication techniques cannot produce a perfect square, giving the square pinholes some amount of roundedness at the corners. This work investigates how this roundedness affects the physical properties of projection images in terms of spatial resolution. Different pinhole full-acceptance angles and roundedness values were simulated. To facilitate a fair comparison, properties of the non-square pinholes were manipulated to yield pinholes with approximately the same sensitivity (to within 0.1%) and FOV (to within 0.5%) as those of the square pinholes, subsequently referred to as matched apertures. The aperture size (flat-to-flat edge length) of each non-square aperture was increased until its sensitivity was approximately equal to that of the square pinhole. Next, the full acceptance angle was increased until the FOV of each non-square aperture was approximately equivalent to that of the square pinhole. Sensitivity was calculated to include both the geometric and penetrative sensitivity of a point source, as well as the packing faction of the multi-pinhole collimator. Using the sensitivity-matched and FOV-matched apertures, spatial resolution was estimated. For the 0.3 mm, 0.5 mm, and 1 mm edge-length square apertures studied, the full-width at half-maximum widened as pinhole shape changed from square to circle, while full-width tenth-maximum showed little change. These results indicate that a perfect square pinhole shape is more desirable than a rounded-square pinhole with regard to spatial resolution when sensitivity and FOV-matched pinholes are compared. (paper)

  7. Stereo Pinhole Camera: Assembly and experimental activities

    Directory of Open Access Journals (Sweden)

    Gilmário Barbosa Santos

    2015-05-01

    Full Text Available This work describes the assembling of a stereo pinhole camera for capturing stereo-pairs of images and proposes experimental activities with it. A pinhole camera can be as sophisticated as you want, or so simple that it could be handcrafted with practically recyclable materials. This paper describes the practical use of the pinhole camera throughout history and currently. Aspects of optics and geometry involved in the building of the stereo pinhole camera are presented with illustrations. Furthermore, experiments are proposed by using the images obtained by the camera for 3D visualization through a pair of anaglyph glasses, and the estimation of relative depth by triangulation is discussed.

  8. Phages of life - the path to pharma.

    Science.gov (United States)

    Forde, Amanda; Hill, Colin

    2018-02-01

    Bacteriophage (phage) therapy has encountered both enthusiasm and scepticism in the past century. New antimicrobial strategies against lethal pathogens are now a top priority for the World Health Organization, and although compassionate use of phages recently met with significant success, regulated clinical interventions seem unlikely in the near future. The hundredth anniversary of their discovery seems an appropriate time for a revival of phage therapy, particularly as the dilemma of antibiotic resistance grows. Phages are ubiquitous in the environment, on our food and in and on our bodies. Their influence on human health is currently being evaluated, and in this mini-review, we examine data from recent metagenomic studies that propose a role for phages in the structure of the microbiome and in health and disease. We assess evidence for phages as vehicles for gene transfer in the context of antibiotic resistance and discuss challenges and opportunities along the critical path from phage discovery to a patient-focused pharmaceutical intervention. © 2017 The British Pharmacological Society.

  9. Basic Phage Mathematics.

    Science.gov (United States)

    Abedon, Stephen T; Katsaounis, Tena I

    2018-01-01

    Basic mathematical descriptions are useful in phage ecology, applied phage ecology such as in the course of phage therapy, and also toward keeping track of expected phage-bacterial interactions as seen during laboratory manipulation of phages. The most basic mathematical descriptor of phages is their titer, that is, their concentration within stocks, experimental vessels, or other environments. Various phenomena can serve to modify phage titers, and indeed phage titers can vary as a function of how they are measured. An important aspect of how changes in titers can occur results from phage interactions with bacteria. These changes tend to vary in degree as a function of bacterial densities within environments, and particularly densities of those bacteria that are susceptible to or at least adsorbable by a given phage type. Using simple mathematical models one can describe phage-bacterial interactions that give rise particularly to phage adsorption events. With elaboration one can consider changes in both phage and bacterial densities as a function of both time and these interactions. In addition, phages along with their impact on bacteria can be considered as spatially constrained processes. In this chapter we consider the simpler of these concepts, providing in particular detailed verbal explanations toward facile mathematical insight. The primary goal is to stimulate a more informed use and manipulation of phages and phage populations within the laboratory as well as toward more effective phage application outside of the laboratory, such as during phage therapy. More generally, numerous issues and approaches to the quantification of phages are considered along with the quantification of individual, ecological, and applied properties of phages.

  10. Variability in DMSA reporting following urinary tract infection in children: pinhole, planar, and pinhole with planar

    International Nuclear Information System (INIS)

    Rossleigh, M.A.; Christian, C.L.; Craig, J.C.; Howman-Giles, R.B.; Grunewald, S.

    2004-01-01

    Purpose: To determine whether the provision of DMSA images obtained by pinhole collimation reduces inter-observer variability of reporting compared with planar DMSA images alone. Methods: One hundred consecutive DMSA images were independently interpreted three times (pinhole alone, planar alone, pinhole and planar) by four participating nuclear medicine specialists from different departments and in random order. The presence or absence of renal parenchymal abnormality was classified using the modified four level grading system of Goldraich with mean values for the 6 comparisons reported. Results: The proportion of DMSA images interpreted as abnormal was 31% for planar, 34% for pinhole and 33% for planar with pinhole. Agreement was 89% for planar alone, 89% for pinhole alone and 90% for planar with pinhole, with kappa values 0.74, 0.75 and 0.80 respectively for the normal-abnormal scan classification of individual children. These results did not vary appreciably whether interpretation of patients, kidneys or kidney zones was compared. Reasons for disagreement in reporting included different interpretations of 'abnormalities' as normal anatomical variations (splenic impression, fetal lobulation, duplex collecting systems, column of Bertin) or true parenchymal abnormalities, different adjustments in thresholds for reporting abnormality when images were technically suboptimal, different weighting given to pinhole and planar images when both were provided, and error. Conclusion: Four experienced nuclear medicine physicians showed substantial agreement in the interpretation of planar alone, pinhole alone and planar with pinhole DMSA images, but the provision of both sets of images, planar and pinhole, did not reduce variability. (authors)

  11. Engineered phages for electronics.

    Science.gov (United States)

    Cui, Yue

    2016-11-15

    Phages are traditionally widely studied in biology and chemistry. In recent years, engineered phages have attracted significant attentions for functionalization or construction of electronic devices, due to their specific binding, catalytic, nucleating or electronic properties. To apply the engineered phages in electronics, these are a number of interesting questions: how to engineer phages for electronics? How are the engineered phages characterized? How to assemble materials with engineered phages? How are the engineered phages micro or nanopatterned? What are the strategies to construct electronics devices with engineered phages? This review will highlight the early attempts to address these questions and explore the fundamental and practical aspects of engineered phages in electronics, including the approaches for selection or expression of specific peptides on phage coat proteins, characterization of engineered phages in electronics, assembly of electronic materials, patterning of engineered phages, and construction of electronic devices. It provides the methodologies and opens up ex-cit-ing op-por-tu-ni-ties for the development of a variety of new electronic materials and devices based on engineered phages for future applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Bacteria, phages and septicemia.

    Directory of Open Access Journals (Sweden)

    Ausra Gaidelyte

    Full Text Available The use of phages is an attractive option to battle antibiotic resistant bacteria in certain bacterial infections, but the role of phage ecology in bacterial infections is obscure. Here we surveyed the phage ecology in septicemia, the most severe type of bacterial infection. We observed that the majority of the bacterial isolates from septicemia patients spontaneously secreted phages active against other isolates of the same bacterial strain, but not to the strain causing the disease. Such phages were also detected in the initial blood cultures, indicating that phages are circulating in the blood at the onset of sepsis. The fact that most of the septicemic bacterial isolates carry functional prophages suggests an active role of phages in bacterial infections. Apparently, prophages present in sepsis-causing bacterial clones play a role in clonal selection during bacterial invasion.

  13. An investigation of inconsistent projections and artefacts in multi-pinhole SPECT with axially aligned pinholes

    International Nuclear Information System (INIS)

    Kench, P L; Meikle, S R; Lin, J; Gregoire, M C

    2011-01-01

    Multiple pinholes are advantageous for maximizing the use of the available field of view (FOV) of compact small animal single photon emission computed tomography (SPECT) detectors. However, when the pinholes are aligned axially to optimize imaging of extended objects, such as rodents, multiplexing of the pinhole projections can give rise to inconsistent data which leads to 'ghost point' artefacts in the reconstructed volume. A novel four pinhole collimator with a baffle was designed and implemented to eliminate these inconsistent projections. Simulation and physical phantom studies were performed to investigate artefacts from axially aligned pinholes and the efficacy of the baffle in removing inconsistent data and, thus, reducing reconstruction artefacts. SPECT was performed using a Defrise phantom to investigate the impact of collimator design on FOV utilization and axial blurring effects. Multiple pinhole SPECT acquired with a baffle had fewer artefacts and improved quantitative accuracy when compared to SPECT acquired without a baffle. The use of four pinholes positioned in a square maximized the available FOV, increased acquisition sensitivity and reduced axial blurring effects. These findings support the use of a baffle to eliminate inconsistent projection data arising from axially aligned pinholes and improve small animal SPECT reconstructions.

  14. Implementation and Evaluation of Pinhole SPECT

    International Nuclear Information System (INIS)

    MacArtain Anne Marie

    2002-08-01

    The aim of this work was to implement Pinhole SPECT into a working Nuclear Medicine department. It has been reported that pinhole SPECT has been successfully performed to visualise pathology in ankle bones using gamma camera and the images were constructed using a standard filtered back-projection algorithm (Bahk YW, 1998). The objective of this study was to produce and evaluate this technique with the equipment available in the nuclear medicine department. The system performance was assessed using both the low-energy high resolution and the pinhole collimators. Phantoms constructed using capillary tubes, filled with technetium 99m (pertechnetate) were imaged in different arrays to identify possible limitations in the reconstruction software. A thyroid phantom with hot and cold inserts was also imaged. Data was acquired in ''tep-and-shoot'' mode as the camera was rotated 180 degrees or 360 degrees around the phantom. Images were reconstructed using standard parallel back-projection algorithm and a weighted backprojection algorithm (Nowak). An attempt was made to process images of the phantom in Matlab using the Iradon function modified by application of a cone-beam type algorithm (Feldkamp L, 1984). Visual comparison of static images between the pinhole and the LEHR collimators showed the expected improved spatial resolution of the pinhole images. Pinhole SPECT images should be reconstructed using the appropriate cone beam algorithm. However, it was established that reconstructing pinhole SPECT images using a standard parallel backprojection algorithm yielded results which were deemed to be clinically useful. The Nowak algorithm results were a distinct improvement on those achieved with the parallel backprojection algorithm. Likewise the results from the cone beam algorithm were better than the former but not as good as those obtained from the Nowak algorithm. This was due to the fact that the cone beam algorithm did not include a weighting factor. Implementation

  15. Numerical simulation for neutron pinhole imaging in ICF

    International Nuclear Information System (INIS)

    Chen Faxin; Yang Jianlun; Wen Shuhuai

    2005-01-01

    Pinhole imaging of the neutron production in laser-driven inertial confinement fusion experiments can provide important information about performance of various capsule designs. In order to get good results in experiments, it is needed to judge performance of various pinhole designs qualitatively or quantitatively before experiment. Calculation of imaging can be simply separated into pinhole imaging and image spectral analysis. In this paper, pinhole imaging is discussed, codes for neutron pinhole imaging and image showing is programed. The codes can be used to provide theoretical foundation for pinhole designing and simulating data for image analysing. (authors)

  16. Absolute quantitative total-body small-animal SPECT with focusing pinholes

    NARCIS (Netherlands)

    Wu, C.; Van der Have, F.; Vastenhouw, B.; Dierckx, R.A.J.O.; Paans, A.M.J.; Beekman, F.J.

    2010-01-01

    Purpose: In pinhole SPECT, attenuation of the photon flux on trajectories between source and pinholes affects quantitative accuracy of reconstructed images. Previously we introduced iterative methods that compensate for image degrading effects of detector and pinhole blurring, pinhole sensitivity

  17. Lysis-deficient phages as novel therapeutic agents for controlling bacterial infection

    Directory of Open Access Journals (Sweden)

    Kempashanaiah Nanjundappa

    2011-08-01

    Full Text Available Abstract Background Interest in phage therapy has grown over the past decade due to the rapid emergence of antibiotic resistance in bacterial pathogens. However, the use of bacteriophages for therapeutic purposes has raised concerns over the potential for immune response, rapid toxin release by the lytic action of phages, and difficulty in dose determination in clinical situations. A phage that kills the target cell but is incapable of host cell lysis would alleviate these concerns without compromising efficacy. Results We developed a recombinant lysis-deficient Staphylococcus aureus phage P954, in which the endolysin gene was rendered nonfunctional by insertional inactivation. P954, a temperate phage, was lysogenized in S. aureus strain RN4220. The native endolysin gene on the prophage was replaced with an endolysin gene disrupted by the chloramphenicol acetyl transferase (cat gene through homologous recombination using a plasmid construct. Lysogens carrying the recombinant phage were detected by growth in presence of chloramphenicol. Induction of the recombinant prophage did not result in host cell lysis, and the phage progeny were released by cell lysis with glass beads. The recombinant phage retained the endolysin-deficient genotype and formed plaques only when endolysin was supplemented. The host range of the recombinant phage was the same as that of the parent phage. To test the in vivo efficacy of the recombinant endolysin-deficient phage, immunocompromised mice were challenged with pathogenic S. aureus at a dose that results in 80% mortality (LD80. Treatment with the endolysin-deficient phage rescued mice from the fatal S. aureus infection. Conclusions A recombinant endolysin-deficient staphylococcal phage has been developed that is lethal to methicillin-resistant S. aureus without causing bacterial cell lysis. The phage was able to multiply in lytic mode utilizing a heterologous endolysin expressed from a plasmid in the propagation host

  18. Ultraviolet inactivation and photoreactivation of the cholera phage 'Kappa'

    International Nuclear Information System (INIS)

    Samad, S.A.; Bhattacharyya, S.C.; Chatterjee, S.N.

    1987-01-01

    The lysogenic cholera phage, 'Kappa' is some ten to twenty folds more resistant to UV (254 nm) than are most of the T. phages of E. coli, or the cholera phage PL 163/10, or the host V. cholerae strain H218 Sm r , the 37% (D 37 ) and 10% (D 10 ) survival doses being 255.8 J/m 2 and 633.6 J/m 2 respectively. The UV-irradiated 'Kappa' phages could be photoreactivated in the host V. cholerae strain H218 Sm r to a maximum extent of 40%. The removal of the number of lethal hits per phage by the survival-enhancement treatment (photoreactivation) with time followed an exponential relation, the constant probability of removal of lethal hit per unit time being 2.8x10 -2 min -1 . The UV-irradiated phages could also be Weigle reactivated in the host strain of H218 Sm r by a small degree, the maximum reactivation factor (ratio of survivals in UV-irradiated and non-irradiated hosts) being 1.50. (orig.)

  19. Improved quantification in single-pinhole and multiple-pinhole SPECT using micro-CT information

    International Nuclear Information System (INIS)

    Vanhove, Christian; Bossuyt, Axel; Defrise, Michel; Lahoutte, Tony

    2009-01-01

    The purpose of this study was to demonstrate the feasibility of accurate quantification in pinhole SPECT using micro-CT information. Pinhole SPECT scans were performed using a clinical dual-head gamma camera. Each pinhole SPECT scan was followed by a micro-CT acquisition. Functional and anatomical images were coregistered using six point sources visible with both modalities. Pinhole SPECT images were reconstructed iteratively. Attenuation correction was based on micro-CT information. Scatter correction was based on dual and triple-energy window methods. Phantom and animal experiments were performed. A phantom containing nine vials was filled with different concentrations of 99m Tc. Three vials were also filled with CT contrast agent to increase attenuation. Activity concentrations measured on the pinhole SPECT images were compared with activity concentrations measured by the dose calibrator. In addition, 11 mice were injected with 99m Tc-labelled Nanobodies. After acquiring functional and anatomical images, the animals were killed and the liver activity was measured using a gamma-counter. Activity concentrations measured on the reconstructed images were compared with activity concentrations measured with the gamma counter. The phantom experiments demonstrated an average error of -27.3 ± 15.9% between the activity concentrations measured on the uncorrected pinhole SPECT images and in the dose calibrator. This error decreased significantly to -0.1 ± 7.3% when corrections were applied for nonuniform attenuation and scatter. The animal experiment revealed an average error of -18.4 ± 11.9% between the activity concentrations measured on the uncorrected pinhole SPECT images and measured with the gamma counter. This error decreased to -7.9 ± 10.4% when attenuation and scatter correction was applied. Attenuation correction obtained from micro-CT data in combination with scatter correction allows accurate quantification in pinhole SPECT. (orig.)

  20. Phage transposon mutagenesis.

    Science.gov (United States)

    Siegrist, M Sloan; Rubin, Eric J

    2009-01-01

    Phage transduction is an attractive method of genetic manipulation in mycobacteria. PhiMycoMarT7 is well suited for transposon mutagenesis as it is temperature sensitive for replication and contains T7 promoters that promote transcription, a highly active transposase gene, and an Escherichia coli oriR6 K origin of replication. Mycobacterial transposon mutant libraries produced by PhiMycoMarT7 transduction are amenable to both forward and reverse genetic studies. In this protocol, we detail the preparation of PhiMycoMarT7, including a description of the phage, reconstitution of the phage, purification of plaques, preparation of phage stock, and titering of phage stock. We then describe the transduction procedure and finally outline the isolation of individual transposon mutants.

  1. Optimizing renal DMSA-scintigraphy with 7-pinhole collimator

    International Nuclear Information System (INIS)

    Botsch, H.; Pottmeyer, A.; Savaser, A.; Lochner, B.; Felix, R.

    1982-01-01

    Multiple pinhole emission tomographic imaging techniques are currently being applied to imaging of organs of a limited size. The purpose of this study was to evaluate the feasibility of this technique in kidney imaging with Tcsup(99m)-DMSA. A 7-pinhole collimator having 4.5 mm. pinhole apertures was used in conjunction with a widefield camera. Left and right kidney were imaged separately. Twelve small renal cysts with a diameter of 1 to 3.5 cm. verified by US or CAT were investigated by 7-pinhole and planar scintigraphy. Eight of 12 renal cysts were identified by 7-pinhole scintigraphy whereas only one cyst was seen by planar scintigraphy. The borderline of cysts detection was 1.5 cm. in 7-pinhole tomography. Basing on these comparative studies and experiences on many patient investigations it seems reasonable to perform renal scintigraphy with 7-pinhole tomography in a routine manner. (orig.)

  2. Lethal Epistaxis.

    Science.gov (United States)

    Byard, Roger W

    2016-09-01

    Epistaxis or nosebleed refers to bleeding from the nostrils, nasal cavity, or nasopharynx. Occasional cases may present with torrential lethal hemorrhage. Three cases are reported to demonstrate particular features: Case 1: A 51-year-old woman with lethal epistaxis with no obvious bleeding source; Case 2: A 77-year-old man with treated nasopharyngeal carcinoma who died from epistaxis arising from a markedly neovascularized tumor bed; Case 3: A 2-year-old boy with hemophilia B who died from epistaxis with airway obstruction in addition to gastrointestinal bleeding. Epistaxis may be associated with trauma, tumors, vascular malformations, bleeding diatheses, infections, pregnancy, endometriosis, and a variety of different drugs. Careful dissection of the nasal cavity is required to locate the site of hemorrhage and to identify any predisposing conditions. This may be guided by postmortem computerized tomographic angiography (PCTA). Despite careful dissection, however, a source of bleeding may never be identified. © 2016 American Academy of Forensic Sciences.

  3. DNA damage and mutagenesis of lambda phage induced by gamma-rays

    International Nuclear Information System (INIS)

    Bertram, Heidi

    1988-01-01

    Lambda phage DNA was gamma irradiated in aqueous solution and strand breakage determined. Twice as much minor structural damage per lethal hit was found in this DNA compared with DNA from irradiated phage suspensions. The in vitro irradiated DNA was repackaged into infectious particles. Induction of mutations in the cI or cII cistron was scored using SOS-induced host cells. In vitro prepared particles were found to have second-order kinetics for mutagenesis induced by gamma rays indicating two pre-mutational events were necessary to produce a mutation, but bacteria-free phage suspensions ('lys-phage') showed single hit kinetics for mutagenesis after irradiation. Increase in the mutation rate in the phage particles was mainly due to minor lesions, i.e. ssb, als and unidentified base damage. In lys-phage, mutagenesis might be enhanced by clustered DNA damage - configuration not existing in pack-phage. Loss of infectivity was analysed in comparison with structural damage. All lesions contributed to biological inactivation. Minor lesions were tolerated by lambda phage to a limited extent. Major lesions (e.g. dsb) contributed most to infectivity loss and were considered lethal events. (U.K.)

  4. Closure phenomena in pinholes irradiated by Nd laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Auerbach, J.M.; Holmes, N.C.; Hunt, J.T.; Linford, G.J.

    1979-07-15

    An experimental investigation has been made on plasma closure in pinholes irradiated by Nd glass laser pulses; 300--500-..mu..m diam pinholes of various materials and thicknesses have been irradiated by 20--100-J 300-psec FWHM pulses on the Janus laser system. Calorimetry measurements have yielded data on pinhole energy transmission and intensity loading on the periphery of the pinhole. Ultrafast streak photography measurements indicate effective closure velocities of 2--5 x 10/sup 7/ cm/sec. Scattered light measurements have shown the transmission loss through a typical spatial filter configuration to be primarily refractive in nature.

  5. Stumbling across the same phage

    DEFF Research Database (Denmark)

    Kalatzis, Panagiotis; Rørbo, Nanna Iben; Castillo Bermúdez, Daniel Elías

    2017-01-01

    46,006 and 54,201 bp. All 19 phages showed high genetic similarity, and 13 phages were genetically identical. Apart from sporadically distributed single nucleotide polymorphisms (SNPs), genetic diversifications were located in three variable regions (VR1, VR2 and VR3) in six of the phage genomes...... was lysogenized by the temperate phages and a genomic analysis of a collection of 31 virulent V. anguillarum showed that the isolated phages were present as prophages in >50% of the strains covering large geographical distances. Further, phage sequences were widely distributed among CRISPR-Cas arrays of publicly...... available sequenced Vibrios. The observed distribution of these specific temperate Vibriophages across large geographical scales may be explained by efficient dispersal of phages and bacteria in the marine environment combined with a mutualistic interaction between temperate phages and their hosts which...

  6. Phage inactivation by triplet acetone

    International Nuclear Information System (INIS)

    Gomes, R.A.

    1985-01-01

    The exposure of lambda phage to triplet acetone is studied. The triplet acetone is obtained from aerobic oxidation of isobutanal catalysed by peroxidase. A decrease of lambda phage ability to infect Escherichia coli is reported, perhaps, partially due to the possible production of lesions in the phage genome. (M.A.C.) [pt

  7. Optimizing multi-pinhole SPECT geometries using an analytical model

    International Nuclear Information System (INIS)

    Rentmeester, M C M; Have, F van der; Beekman, F J

    2007-01-01

    State-of-the-art multi-pinhole SPECT devices allow for sub-mm resolution imaging of radio-molecule distributions in small laboratory animals. The optimization of multi-pinhole and detector geometries using simulations based on ray-tracing or Monte Carlo algorithms is time-consuming, particularly because many system parameters need to be varied. As an efficient alternative we develop a continuous analytical model of a pinhole SPECT system with a stationary detector set-up, which we apply to focused imaging of a mouse. The model assumes that the multi-pinhole collimator and the detector both have the shape of a spherical layer, and uses analytical expressions for effective pinhole diameters, sensitivity and spatial resolution. For fixed fields-of-view, a pinhole-diameter adapting feedback loop allows for the comparison of the system resolution of different systems at equal system sensitivity, and vice versa. The model predicts that (i) for optimal resolution or sensitivity the collimator layer with pinholes should be placed as closely as possible around the animal given a fixed detector layer, (ii) with high-resolution detectors a resolution improvement up to 31% can be achieved compared to optimized systems, (iii) high-resolution detectors can be placed close to the collimator without significant resolution losses, (iv) interestingly, systems with a physical pinhole diameter of 0 mm can have an excellent resolution when high-resolution detectors are used

  8. Estimate of energy density on CYCLOPS spatial filter pinhole structure

    International Nuclear Information System (INIS)

    Guch, S. Jr.

    1974-01-01

    The inclusion of a spatial filter between the B and C stages in CYCLOPS to reduce the effects of small-scale beam self-focusing is discussed. An estimate is made of the energy density to which the pinhole will be subjected, and the survivability of various pinhole materials and designs is discussed

  9. Proton pinhole imaging on the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Zylstra, A. B., E-mail: zylstra@lanl.gov [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Park, H.-S.; Ross, J. S.; Higginson, D. P.; Huntington, C.; Pollock, B.; Remington, B.; Rinderknecht, H. G.; Ryutov, D.; Turnbull, D.; Wilks, S. C. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Fiuza, F. [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Frenje, J. A.; Li, C. K.; Petrasso, R. D.; Séguin, F. H. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2016-11-15

    Pinhole imaging of large (mm scale) carbon-deuterium (CD) plasmas by proton self-emission has been used for the first time to study the microphysics of shock formation, which is of astrophysical relevance. The 3 MeV deuterium-deuterium (DD) fusion proton self-emission from these plasmas is imaged using a novel pinhole imaging system, with up to five different 1 mm diameter pinholes positioned 25 cm from target-chamber center. CR39 is used as the detector medium, positioned at 100 cm distance from the pinhole for a magnification of 4 ×. A Wiener deconvolution algorithm is numerically demonstrated and used to interpret the images. When the spatial morphology is known, this algorithm accurately reproduces the size of features larger than about half the pinhole diameter. For these astrophysical plasma experiments on the National Ignition Facility, this provides a strong constraint on simulation modeling of the experiment.

  10. Nongenetic individuality in the host-phage interaction.

    Directory of Open Access Journals (Sweden)

    Sivan Pearl

    2008-05-01

    Full Text Available Isogenic bacteria can exhibit a range of phenotypes, even in homogeneous environmental conditions. Such nongenetic individuality has been observed in a wide range of biological processes, including differentiation and stress response. A striking example is the heterogeneous response of bacteria to antibiotics, whereby a small fraction of drug-sensitive bacteria can persist under extensive antibiotic treatments. We have previously shown that persistent bacteria enter a phenotypic state, identified by slow growth or dormancy, which protects them from the lethal action of antibiotics. Here, we studied the effect of persistence on the interaction between Escherichia coli and phage lambda. We used long-term time-lapse microscopy to follow the expression of green fluorescent protein (GFP under the phage lytic promoter, as well as cellular fate, in single infected bacteria. Intriguingly, we found that, whereas persistent bacteria are protected from prophage induction, they are not protected from lytic infection. Quantitative analysis of gene expression reveals that the expression of lytic genes is suppressed in persistent bacteria. However, when persistent bacteria switch to normal growth, the infecting phage resumes the process of gene expression, ultimately causing cell lysis. Using mathematical models for these two host-phage interactions, we found that the bacteria's nongenetic individuality can significantly affect the population dynamics, and might be relevant for understanding the coevolution of bacterial hosts and phages.

  11. Synergy as a rationale for phage therapy using phage cocktails.

    Science.gov (United States)

    Schmerer, Matthew; Molineux, Ian J; Bull, James J

    2014-01-01

    Where phages are used to treat bacterial contaminations and infections, multiple phages are typically applied at once as a cocktail. When two or more phages in the cocktail attack the same bacterium, the combination may produce better killing than any single phage (synergy) or the combination may be worse than the best single phage (interference). Synergy is of obvious utility, especially if it can be predicted a priori, but it remains poorly documented with few examples known. This study addresses synergy in which one phage improves adsorption by a second phage. It first presents evidence of synergy from an experimental system of two phages and a mucoid E. coli host. The synergy likely stems from a tailspike enzyme produced by one of the phages. We then offer mathematical models and simulations to understand the dynamics of synergy and the enhanced magnitude of bacterial control possible. The models and observations complement each other and suggest that synergy may be of widespread utility and may be predictable from easily observed phenotypes.

  12. Nano-displacement measurement based on virtual pinhole confocal method

    International Nuclear Information System (INIS)

    Li, Long; Kuang, Cuifang; Xue, Yi; Liu, Xu

    2013-01-01

    A virtual pinhole confocal system based on charge-coupled device (CCD) detection and image processing techniques is built to measure axial displacement with 10 nm resolution, preeminent flexibility and excellent robustness when facing spot drifting. Axial displacement of the sample surface is determined by capturing the confocal laser spot using a CCD detector and quantifying the energy collected by programmable virtual pinholes. Experiments indicate an applicable measuring range of 1000 nm (Gaussian fitting r = 0.9902) with a highly linear range of 500 nm (linear fitting r = 0.9993). A concentric subtraction algorithm is introduced to further enhance resolution. Factors affecting measuring precision, sensitivity and signal-to-noise ratio are discussed using theoretical deductions and diffraction simulations. The virtual pinhole technique has promising applications in surface profiling and confocal imaging applications which require easily-customizable pinhole configurations. (paper)

  13. Research On The Measure Method Of Oblique Pinhole Parameters

    Directory of Open Access Journals (Sweden)

    Ma Yu-Zhen

    2016-01-01

    Full Text Available There are many special advantages in measuring the diameter of blind and deep holes with a capacitive probe, there are still some challenges for the measurement of a oblique pinhole parameters because the measuring device is inconvenient to stretch into the oblique pinhole exactly. A five-dimensional measurement system was adopted in the paper which included a capacitive sensor probe and a three-coordinate measuring machine to accomplish the measurement for oblique pinholes. With the help of the three-dimensional coordinates measured from the pinhole axis, we put forward a comprehensive method of combining the projection method and the least squares method together for fitting spatial straight line to obtain the optimal equation of the spacial axis. Finally, a reliable and entire measurement system was set up.

  14. Diffraction phase microscopy realized with an automatic digital pinhole

    Science.gov (United States)

    Zheng, Cheng; Zhou, Renjie; Kuang, Cuifang; Zhao, Guangyuan; Zhang, Zhimin; Liu, Xu

    2017-12-01

    We report a novel approach to diffraction phase microscopy (DPM) with automatic pinhole alignment. The pinhole, which serves as a spatial low-pass filter to generate a uniform reference beam, is made out of a liquid crystal display (LCD) device that allows for electrical control. We have made DPM more accessible to users, while maintaining high phase measurement sensitivity and accuracy, through exploring low cost optical components and replacing the tedious pinhole alignment process with an automatic pinhole optical alignment procedure. Due to its flexibility in modifying the size and shape, this LCD device serves as a universal filter, requiring no future replacement. Moreover, a graphic user interface for real-time phase imaging has been also developed by using a USB CMOS camera. Experimental results of height maps of beads sample and live red blood cells (RBCs) dynamics are also presented, making this system ready for broad adaption to biological imaging and material metrology.

  15. Expert Opinion on Three Phage Therapy Related Topics: Bacterial Phage Resistance, Phage Training and Prophages in Bacterial Production Strains

    Directory of Open Access Journals (Sweden)

    Christine Rohde

    2018-04-01

    Full Text Available Phage therapy is increasingly put forward as a “new” potential tool in the fight against antibiotic resistant infections. During the “Centennial Celebration of Bacteriophage Research” conference in Tbilisi, Georgia on 26–29 June 2017, an international group of phage researchers committed to elaborate an expert opinion on three contentious phage therapy related issues that are hampering clinical progress in the field of phage therapy. This paper explores and discusses bacterial phage resistance, phage training and the presence of prophages in bacterial production strains while reviewing relevant research findings and experiences. Our purpose is to inform phage therapy stakeholders such as policy makers, officials of the competent authorities for medicines, phage researchers and phage producers, and members of the pharmaceutical industry. This brief also points out potential avenues for future phage therapy research and development as it specifically addresses those overarching questions that currently call for attention whenever phages go into purification processes for application.

  16. Fast and accurate focusing analysis of large photon sieve using pinhole ring diffraction model.

    Science.gov (United States)

    Liu, Tao; Zhang, Xin; Wang, Lingjie; Wu, Yanxiong; Zhang, Jizhen; Qu, Hemeng

    2015-06-10

    In this paper, we developed a pinhole ring diffraction model for the focusing analysis of a large photon sieve. Instead of analyzing individual pinholes, we discuss the focusing of all of the pinholes in a single ring. An explicit equation for the diffracted field of individual pinhole ring has been proposed. We investigated the validity range of this generalized model and analytically describe the sufficient conditions for the validity of this pinhole ring diffraction model. A practical example and investigation reveals the high accuracy of the pinhole ring diffraction model. This simulation method could be used for fast and accurate focusing analysis of a large photon sieve.

  17. Modeling of Pixelated Detector in SPECT Pinhole Reconstruction.

    Science.gov (United States)

    Feng, Bing; Zeng, Gengsheng L

    2014-04-10

    A challenge for the pixelated detector is that the detector response of a gamma-ray photon varies with the incident angle and the incident location within a crystal. The normalization map obtained by measuring the flood of a point-source at a large distance can lead to artifacts in reconstructed images. In this work, we investigated a method of generating normalization maps by ray-tracing through the pixelated detector based on the imaging geometry and the photo-peak energy for the specific isotope. The normalization is defined for each pinhole as the normalized detector response for a point-source placed at the focal point of the pinhole. Ray-tracing is used to generate the ideal flood image for a point-source. Each crystal pitch area on the back of the detector is divided into 60 × 60 sub-pixels. Lines are obtained by connecting between a point-source and the centers of sub-pixels inside each crystal pitch area. For each line ray-tracing starts from the entrance point at the detector face and ends at the center of a sub-pixel on the back of the detector. Only the attenuation by NaI(Tl) crystals along each ray is assumed to contribute directly to the flood image. The attenuation by the silica (SiO 2 ) reflector is also included in the ray-tracing. To calculate the normalization for a pinhole, we need to calculate the ideal flood for a point-source at 360 mm distance (where the point-source was placed for the regular flood measurement) and the ideal flood image for the point-source at the pinhole focal point, together with the flood measurement at 360 mm distance. The normalizations are incorporated in the iterative OSEM reconstruction as a component of the projection matrix. Applications to single-pinhole and multi-pinhole imaging showed that this method greatly reduced the reconstruction artifacts.

  18. Targeting mammalian organelles with internalizing phage (iPhage) libraries

    Science.gov (United States)

    Rangel, Roberto; Dobroff, Andrey S.; Guzman-Rojas, Liliana; Salmeron, Carolina C.; Gelovani, Juri G.; Sidman, Richard L.; Pasqualini, Renata; Arap, Wadih

    2015-01-01

    Techniques largely used for protein interaction studies and discovery of intracellular receptors, such as affinity capture complex purification and yeast two-hybrid, may produce inaccurate datasets due to protein insolubility, transient or weak protein interactions, or irrelevant intracellular context. A versatile tool to overcome these limitations as well as to potentially create vaccines and engineer peptides and antibodies as targeted diagnostic and therapeutic agents, is the phage display technique. We have recently developed a new technology for screening internalizing phage (iPhage) vectors and libraries utilizing a ligand/receptor-independent mechanism to penetrate eukaryotic cells. iPhage particles provide a unique discovery platform for combinatorial intracellular targeting of organelle ligands along with their corresponding receptors and to fingerprint functional protein domains in living cells. Here we explain the design, cloning, construction, and production of iPhage-based vectors and libraries, along with basic ligand-receptor identification and validation methodologies for organelle receptors. An iPhage library screening can be performed in ~8 weeks. PMID:24030441

  19. Phages in the Human Body.

    Science.gov (United States)

    Navarro, Ferran; Muniesa, Maite

    2017-01-01

    Bacteriophages, viruses that infect bacteria, have re-emerged as powerful regulators of bacterial populations in natural ecosystems. Phages invade the human body, just as they do other natural environments, to such an extent that they are the most numerous group in the human virome. This was only revealed in recent metagenomic studies, despite the fact that the presence of phages in the human body was reported decades ago. The influence of the presence of phages in humans has yet to be evaluated; but as in marine environments, a clear role in the regulation of bacterial populations could be envisaged, that might have an impact on human health. Moreover, phages are excellent vehicles of genetic transfer, and they contribute to the evolution of bacterial cells in the human body by spreading and acquiring DNA horizontally. The abundance of phages in the human body does not pass unnoticed and the immune system reacts to them, although it is not clear to what extent. Finally, the presence of phages in human samples, which most of the time is not considered, can influence and bias microbiological and molecular results; and, in view of the evidences, some studies suggest that more attention needs to be paid to their interference.

  20. Current insights into phage biodiversity and biogeography.

    Science.gov (United States)

    Thurber, Rebecca Vega

    2009-10-01

    Phages exert tremendous ecological and evolutionary forces directly on their bacterial hosts. Phage induced cell lysis also indirectly contributes to organic and inorganic nutrient recycling. Phage abundance, diversity, and distribution are therefore important parameters in ecosystem function. The assumption that phage consortia are ubiquitous and homogenous across habitats (everything is everywhere) is currently being re-evaluated. New studies on phage biogeography have found that some phages are globally distributed while others are unique and perhaps endemic to specific environments. Furthermore, advances in technology have allowed scientists to conduct experiments aimed at analyzing phage consortia over temporal scales, and surprisingly have found reoccurring patterns. This review discusses currents in the field of phage ecology with particular focus on efforts to characterize phage diversity and biogeography across various spatial and temporal scales.

  1. An Evaluation of Pinhole Castration as an Alternative Technique for ...

    African Journals Online (AJOL)

    We evaluated pinhole castration as an alternative technique for dog population control in resource poor rural communities of Gulu, Northern Uganda. Through a campaign dubbed 'Big Fix Gulu', households in selected communities were mobilized using radio announcements, posters and school visits, to present dogs for ...

  2. COPPER PITTING CORROSION AND PINHOLE LEAKS: A CASE STUDY

    Science.gov (United States)

    Localized corrosion, or "pitting", of copper drinking water pipe continues is a problem for many water utilities and their customers. Extreme attack leads to pinhole leaks that can potentially lead to water damage, mold growth, and costly repairs for the homeowners, as well as th...

  3. Synthetic Phage for Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    So Young Yoo

    2014-01-01

    Full Text Available Controlling structural organization and signaling motif display is of great importance to design the functional tissue regenerating materials. Synthetic phage, genetically engineered M13 bacteriophage has been recently introduced as novel tissue regeneration materials to display a high density of cell-signaling peptides on their major coat proteins for tissue regeneration purposes. Structural advantages of their long-rod shape and monodispersity can be taken together to construct nanofibrous scaffolds which support cell proliferation and differentiation as well as direct orientation of their growth in two or three dimensions. This review demonstrated how functional synthetic phage is designed and subsequently utilized for tissue regeneration that offers potential cell therapy.

  4. Linear micromechanical stepping drive for pinhole array positioning

    International Nuclear Information System (INIS)

    Endrödy, Csaba; Mehner, Hannes; Hoffmann, Martin; Grewe, Adrian

    2015-01-01

    A compact linear micromechanical stepping drive for positioning a 7 × 5.5 mm 2 optical pinhole array is presented. The system features a step size of 13.2 µm and a full displacement range of 200 µm. The electrostatic inch-worm stepping mechanism shows a compact design capable of positioning a payload 50% of its own weight. The stepping drive movement, step sizes and position accuracy are characterized. The actuated pinhole array is integrated in a confocal chromatic hyperspectral imaging system, where coverage of the object plane, and therefore the useful picture data, can be multiplied by 14 in contrast to a non-actuated array. (paper)

  5. Oxidative Attack of Carbon/Carbon Substrates through Coating Pinholes

    Science.gov (United States)

    Jacobson, Nathan S.; Leonhardt, Todd; Curry, Donald; Rapp, Robert A.

    1998-01-01

    A critical issue with oxidation protected carbon/carbon composites used for spacecraft thermal protection is the formation of coating pinholes. In laboratory experiments, artificial pinholes were drilled through SiC-coatings on a carbon/carbon material and the material was oxidized at 600, 1000, and 1400 C at reduced pressures of air. The attack of the carbon/carbon was quantified by both weight loss and a novel cross-sectioning technique. A two-zone, one dimensional diffusion control model was adapted to analyze this problem. Agreement of the model with experiment was reasonable at 1000 and 1400 C; however results at lower temperatures show clear deviations from the theory suggesting that surface reaction control plays a role.

  6. Radiation inactivation of T7 phage

    International Nuclear Information System (INIS)

    Becker, D.; Redpath, J.L.; Grossweiner, L.I.

    1978-01-01

    The radiation inactivation of T7 phage by 25-MeV electron pulses has been measured in various media containing a wide concentration range of radical scavenging solutes and in the presence of protective and sensitizing agents. The dependence of sensitivity on pulse dose, from 1 mrad to 3.6 krad, is attributed to radical depletion via bimolecular processes. The survival data are analyzed by extending target theory to include diffusive reactions of primary and secondary radicals generated in the medium. It is concluded that OH radicals are the principal primary inactivating species and that secondary radicals from Br - , CNS - , uracil, glucose, ribose, sucrose, tyrosine, and histidine are lethal to some extent. In nutrient broth or 100 mM histidine, psoralen derivatives, Actinomycin D, and Mitomycin C are anoxic sensitizers. It is proposed that the psoralens promote the formation of non-strand break lesions as the sensitization mechanism. The target theory based on diffusional kinetics is applicable to other systems including single cells

  7. A new reconstruction strategy for image improvement in pinhole SPECT

    International Nuclear Information System (INIS)

    Zeniya, Tsutomu; Watabe, Hiroshi; Kim, Kyeong Min; Teramoto, Noboru; Hayashi, Takuya; Iida, Hidehiro; Aoi, Toshiyuki; Sohlberg, Antti; Kudo, Hiroyuki

    2004-01-01

    Pinhole single-photon emission computed tomography (SPECT) is able to provide information on the biodistribution of several radioligands in small laboratory animals, but has limitations associated with non-uniform spatial resolution or axial blurring. We have hypothesised that this blurring is due to incompleteness of the projection data acquired by a single circular pinhole orbit, and have evaluated a new strategy for accurate image reconstruction with better spatial resolution uniformity. A pinhole SPECT system using two circular orbits and a dedicated three-dimensional ordered subsets expectation maximisation (3D-OSEM) reconstruction method were developed. In this system, not the camera but the object rotates, and the two orbits are at 90 and 45 relative to the object's axis. This system satisfies Tuy's condition, and is thus able to provide complete data for 3D pinhole SPECT reconstruction within the whole field of view (FOV). To evaluate this system, a series of experiments was carried out using a multiple-disk phantom filled with 99m Tc solution. The feasibility of the proposed method for small animal imaging was tested with a mouse bone study using 99m Tc-hydroxymethylene diphosphonate. Feldkamp's filtered back-projection (FBP) method and the 3D-OSEM method were applied to these data sets, and the visual and statistical properties were examined. Axial blurring, which was still visible at the edge of the FOV even after applying the conventional 3D-OSEM instead of FBP for single-orbit data, was not visible after application of 3D-OSEM using two-orbit data. 3D-OSEM using two-orbit data dramatically reduced the resolution non-uniformity and statistical noise, and also demonstrated considerably better image quality in the mouse scan. This system may be of use in quantitative assessment of bio-physiological functions in small animals. (orig.)

  8. Use of Gamma Correction Pinhole Bone Scans in Trauma

    International Nuclear Information System (INIS)

    Bahk, Youg Whee; Chung, Youg An; Park, Jung Mee

    2012-01-01

    99 mTc hydroxydiphosphonate (HDP) bone scanning is a classic metabolic nuclear imaging method and the most frequently performed examination. Clinically, it has long been cherished as an indispensable diagnostic screening tool and for monitoring of patients with bone, joint, and soft tissue diseases. The HDP bone scan, the pinhole scan in particular, is known for its ability to detect increased, decreased, or defective tracer uptake along with magnified anatomy. Unfortunately, however, the findings of such uptake changes are not specific in many traumatic bone disorders, especially when lesions are minute and complex. This study discusses the recently introduced gamma correction pinhole bone scan (GCPBS), emphasizing its usefulness in the diagnosis of traumatic bone diseases including occult fractures; and fish vertebra. Indeed, GCPBS can remarkably enhance the diagnostic feasibility of HDP pinhole bone scans by refining the topography, pathologic anatomy, and altered chemical profile of the traumatic diseases in question. The fine and precise depiction of anatomic and metabolic changes in these diseases has been shown to be unique to GCPBS, and they are not appreciated on conventional radiographs, multiple detector CT, or ultrasonographs. It is true that MR imaging can portray proton change, but understandably, it is a manifestation that is common to any bone disease

  9. Phage typing of Staphylococcus saprophyticus.

    Science.gov (United States)

    Torres Pereira, A.; Melo Cristino, J. A.

    1991-01-01

    This study included 502 staphylococcus strains; Staphylococcus saprophyticus (297 strains) S. cohnii (47), S. xylosus (10), S. epidermidis (67) and S. aureus (81). Mitomycin C induction was performed on 100 isolates of S. saprophyticus and all induced strains were reacted with each other. Twenty-six strains proved to be lysogenic. Phages were propagated and titrated. With 12 of the phages there were three frequent associations, named lytic groups A, B and C, which included 75% of all typable strains. Typability of the system was 45% and reproducibility was between 94.2% and 100%. Phages did not lyse S. aureus and S. epidermidis strains, but they lysed S. saprophyticus and only rare strains of other novobiocin resistant species. Effective S. saprophyticus typing serves ecological purposes and tracing the origin of urinary strains from the skin or mucous membranes. Phage typing in association with plasmid profiling previously described, are anticipated as complementary methods with strong discriminatory power for differentiating among S. saprophyticus strains. PMID:1752305

  10. Phage lytic enzymes: a history.

    Science.gov (United States)

    Trudil, David

    2015-02-01

    There are many recent studies regarding the efficacy of bacteriophage-related lytic enzymes: the enzymes of 'bacteria-eaters' or viruses that infect bacteria. By degrading the cell wall of the targeted bacteria, these lytic enzymes have been shown to efficiently lyse Gram-positive bacteria without affecting normal flora and non-related bacteria. Recent studies have suggested approaches for lysing Gram-negative bacteria as well (Briersa Y, et al., 2014). These enzymes include: phage-lysozyme, endolysin, lysozyme, lysin, phage lysin, phage lytic enzymes, phageassociated enzymes, enzybiotics, muralysin, muramidase, virolysin and designations such as Ply, PAE and others. Bacteriophages are viruses that kill bacteria, do not contribute to antimicrobial resistance, are easy to develop, inexpensive to manufacture and safe for humans, animals and the environment. The current focus on lytic enzymes has been on their use as anti-infectives in humans and more recently in agricultural research models. The initial translational application of lytic enzymes, however, was not associated with treating or preventing a specific disease but rather as an extraction method to be incorporated in a rapid bacterial detection assay (Bernstein D, 1997).The current review traces the translational history of phage lytic enzymes-from their initial discovery in 1986 for the rapid detection of group A streptococcus in clinical specimens to evolving applications in the detection and prevention of disease in humans and in agriculture.

  11. Investigation of the hard x-ray background in backlit pinhole imagers

    Energy Technology Data Exchange (ETDEWEB)

    Fein, J. R., E-mail: jrfein@umich.edu; Holloway, J. P. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109-2143 (United States); Peebles, J. L. [Center for Energy Research, University of California, San Diego, La Jolla, California 92093 (United States); Keiter, P. A.; Klein, S. R.; Kuranz, C. C.; Manuel, M. J.-E.; Drake, R. P. [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109-2143 (United States)

    2014-11-15

    Hard x-rays from laser-produced hot electrons (>10 keV) in backlit pinhole imagers can give rise to a background signal that decreases signal dynamic range in radiographs. Consequently, significant uncertainties are introduced to the measured optical depth of imaged plasmas. Past experiments have demonstrated that hard x-rays are produced when hot electrons interact with the high-Z pinhole substrate used to collimate the softer He-α x-ray source. Results are presented from recent experiments performed on the OMEGA-60 laser to further study the production of hard x-rays in the pinhole substrate and how these x-rays contribute to the background signal in radiographs. Radiographic image plates measured hard x-rays from pinhole imagers with Mo, Sn, and Ta pinhole substrates. The variation in background signal between pinhole substrates provides evidence that much of this background comes from x-rays produced in the pinhole substrate itself. A Monte Carlo electron transport code was used to model x-ray production from hot electrons interacting in the pinhole substrate, as well as to model measurements of x-rays from the irradiated side of the targets, recorded by a bremsstrahlung x-ray spectrometer. Inconsistencies in inferred hot electron distributions between the different pinhole substrate materials demonstrate that additional sources of hot electrons beyond those modeled may produce hard x-rays in the pinhole substrate.

  12. The habits of highly effective phages: population dynamics as a framework for identifying therapeutic phages

    Directory of Open Access Journals (Sweden)

    James J Bull

    2014-11-01

    Full Text Available The use of bacteriophages as antibacterial agents is being actively researched on a global scale. Typically, the phages used are isolated from the wild by plating on the bacteria of interest, and a far larger set of candidate phages is often available than can be used in any application. When an excess of phages is available, how should the best phages be identified? Here we consider phage-bacterial population dynamics as a basis for evaluating and predicting phage success. A central question is whether the innate dynamical properties of phages are the determinants of success, or instead, whether extrinsic, indirect effects can be responsible. We address the dynamical perspective, motivated in part by the absence of dynamics in previously suggested principles of phage therapy. Current mathematical models of bacterial-phage dynamics do not capture the realities of in vivo dynamics, nor is this likely to change, but they do give insight to qualitative properties that may be generalizable. In particular, phage adsorption rate may be critical to treatment success, so understanding the effects of the in vivo environment on host availability may allow prediction of useful phages prior to in vivo experimentation. Principles for predicting efficacy may be derived by developing a greater understanding of the in vivo system, or such principles could be determined empirically by comparing phages with known differences in their dynamic properties. The comparative approach promises to be a powerful method of discovering the key to phage success. We offer five recommendations for future study: (i compare phages differing in treatment efficacy to identify the phage properties associated with success, (ii assay dynamics in vivo, (iii understand mechanisms of bacterial escape from phages, (iv test phages in model infections that are relevant to the intended clinical applications, and (v develop new classes of models for phage growth in spatially heterogeneous

  13. Recombinant phage probes for Listeria monocytogenes

    Energy Technology Data Exchange (ETDEWEB)

    Carnazza, S; Gioffre, G; Felici, F; Guglielmino, S [Department of Microbiological, Genetic and Molecular Sciences, University of Messina, Messina (Italy)

    2007-10-03

    Monitoring of food and environmental samples for biological threats, such as Listeria monocytogenes, requires probes that specifically bind biological agents and ensure their immediate and efficient detection. There is a need for robust and inexpensive affinity probes as an alternative to antibodies. These probes may be recruited from random peptide libraries displayed on filamentous phage. In this study, we selected from two phage peptide libraries phage clones displaying peptides capable of specific and strong binding to the L. monocytogenes cell surface. The ability of isolated phage clones to interact specifically with L. monocytogenes was demonstrated using enzyme-linked immunosorbent assay (ELISA) and confirmed by co-precipitation assay. We also assessed the sensitivity of phage-bacteria binding by PCR on phage-captured Listeria cells, which could be detected at a concentration of 10{sup 4} cells ml{sup -1}. In addition, as proof-of-concept, we tested the possibility of immobilizing the affinity-selected phages to a putative biosensor surface. The quality of phage deposition was monitored by ELISA and fluorescent microscopy. Phage-bacterial binding was confirmed by high power optical phase contrast microscopy. Overall, the results of this work validate the concept of affinity-selected recombinant filamentous phages as probes for detecting and monitoring bacterial agents under any conditions that warrant their recognition, including in food products.

  14. Recombinant phage probes for Listeria monocytogenes

    Science.gov (United States)

    Carnazza, S.; Gioffrè, G.; Felici, F.; Guglielmino, S.

    2007-10-01

    Monitoring of food and environmental samples for biological threats, such as Listeria monocytogenes, requires probes that specifically bind biological agents and ensure their immediate and efficient detection. There is a need for robust and inexpensive affinity probes as an alternative to antibodies. These probes may be recruited from random peptide libraries displayed on filamentous phage. In this study, we selected from two phage peptide libraries phage clones displaying peptides capable of specific and strong binding to the L. monocytogenes cell surface. The ability of isolated phage clones to interact specifically with L. monocytogenes was demonstrated using enzyme-linked immunosorbent assay (ELISA) and confirmed by co-precipitation assay. We also assessed the sensitivity of phage-bacteria binding by PCR on phage-captured Listeria cells, which could be detected at a concentration of 104 cells ml-1. In addition, as proof-of-concept, we tested the possibility of immobilizing the affinity-selected phages to a putative biosensor surface. The quality of phage deposition was monitored by ELISA and fluorescent microscopy. Phage-bacterial binding was confirmed by high power optical phase contrast microscopy. Overall, the results of this work validate the concept of affinity-selected recombinant filamentous phages as probes for detecting and monitoring bacterial agents under any conditions that warrant their recognition, including in food products.

  15. Phage Therapy: Eco-Physiological Pharmacology

    Directory of Open Access Journals (Sweden)

    Stephen T. Abedon

    2014-01-01

    Full Text Available Bacterial virus use as antibacterial agents, in the guise of what is commonly known as phage therapy, is an inherently physiological, ecological, and also pharmacological process. Physiologically we can consider metabolic properties of phage infections of bacteria and variation in those properties as a function of preexisting bacterial states. In addition, there are patient responses to pathogenesis, patient responses to phage infections of pathogens, and also patient responses to phage virions alone. Ecologically, we can consider phage propagation, densities, distribution (within bodies, impact on body-associated microbiota (as ecological communities, and modification of the functioning of body “ecosystems” more generally. These ecological and physiological components in many ways represent different perspectives on otherwise equivalent phenomena. Comparable to drugs, one also can view phages during phage therapy in pharmacological terms. The relatively unique status of phages within the context of phage therapy as essentially replicating antimicrobials can therefore result in a confluence of perspectives, many of which can be useful towards gaining a better mechanistic appreciation of phage therapy, as I consider here. Pharmacology more generally may be viewed as a discipline that lies at an interface between organism-associated phenomena, as considered by physiology, and environmental interactions as considered by ecology.

  16. High-Damage-Threshold Pinhole for Glass Fusion Laser Applications

    International Nuclear Information System (INIS)

    Kumit, N.A.; Letzring, S.A.; Johnson, R.P.

    1998-01-01

    We are investigating methods to fabricate high-damage-threshold spatial-filter pinholes that might not be susceptible to plasma closure for relatively high energies and long pulses. These are based on the observation that grazing-incidence reflection from glass can withstand in excess of 5 kJ/cm 2 (normal to the beam) without plasma formation. The high damage threshold results from both the cos q spreading of the energy across the surface and the reflection of a large fraction of the energy from the surface, thereby greatly reducing the field strength within the medium

  17. Basics of Antibody Phage Display Technology.

    Science.gov (United States)

    Ledsgaard, Line; Kilstrup, Mogens; Karatt-Vellatt, Aneesh; McCafferty, John; Laustsen, Andreas H

    2018-06-09

    Antibody discovery has become increasingly important in almost all areas of modern medicine. Different antibody discovery approaches exist, but one that has gained increasing interest in the field of toxinology and antivenom research is phage display technology. In this review, the lifecycle of the M13 phage and the basics of phage display technology are presented together with important factors influencing the success rates of phage display experiments. Moreover, the pros and cons of different antigen display methods and the use of naïve versus immunized phage display antibody libraries is discussed, and selected examples from the field of antivenom research are highlighted. This review thus provides in-depth knowledge on the principles and use of phage display technology with a special focus on discovery of antibodies that target animal toxins.

  18. Control of Pierce's Disease by Phage.

    Directory of Open Access Journals (Sweden)

    Mayukh Das

    Full Text Available Pierce's Disease (PD of grapevines, caused by Xylella fastidiosa subsp. fastidiosa (Xf, is a limiting factor in the cultivation of grapevines in the US. There are presently no effective control methods to prevent or treat PD. The therapeutic and prophylactic efficacy of a phage cocktail composed of four virulent (lytic phages was evaluated for control of PD. Xf levels in grapevines were significantly reduced in therapeutically or prophylactically treated grapevines. PD symptoms ceased to progress one week post-therapeutic treatment and symptoms were not observed in prophylactically treated grapevines. Cocktail phage levels increased in grapevines in the presence of the host. No in planta phage-resistant Xf isolates were obtained. Moreover, Xf mutants selected for phage resistance in vitro did not cause PD symptoms. Our results indicate that phages have great potential for biocontrol of PD and other economically important diseases caused by Xylella.

  19. [Peptide phage display in biotechnology and biomedicine].

    Science.gov (United States)

    Kuzmicheva, G A; Belyavskaya, V A

    2016-07-01

    To date peptide phage display is one of the most common combinatorial methods used for identifying specific peptide ligands. Phage display peptide libraries containing billions different clones successfully used for selection of ligands with high affinity and selectivity toward wide range of targets including individual proteins, bacteria, viruses, spores, different kind of cancer cells and variety of nonorganic targets (metals, alloys, semiconductors etc.) Success of using filamentous phage in phage display technologies relays on the robustness of phage particles and a possibility to genetically modify its DNA to construct new phage variants with novel properties. In this review we are discussing characteristics of the most known non-commercial peptide phage display libraries of different formats (landscape libraries in particular) and their successful applications in several fields of biotechnology and biomedicine: discovery of peptides with diagnostic values against different pathogens, discovery and using of peptides recognizing cancer cells, trends in using of phage display technologies in human interactome studies, application of phage display technologies in construction of novel nano materials.

  20. Image reconstruction methods for the PBX-M pinhole camera

    International Nuclear Information System (INIS)

    Holland, A.; Powell, E.T.; Fonck, R.J.

    1990-03-01

    This paper describes two methods which have been used to reconstruct the soft x-ray emission profile of the PBX-M tokamak from the projected images recorded by the PBX-M pinhole camera. Both methods must accurately represent the shape of the reconstructed profile while also providing a degree of immunity to noise in the data. The first method is a simple least squares fit to the data. This has the advantage of being fast and small, and thus easily implemented on the PDP-11 computer used to control the video digitizer for the pinhole camera. The second method involves the application of a maximum entropy algorithm to an overdetermined system. This has the advantage of allowing the use of a default profile. This profile contains additional knowledge about the plasma shape which can be obtained from equilibrium fits to the external magnetic measurements. Additionally the reconstruction is guaranteed positive, and the fit to the data can be relaxed by specifying both the amount and distribution of noise in the image. The algorithm described has the advantage of being considerably faster, for an overdetermined system, than the usual Lagrange multiplier approach to finding the maximum entropy solution. 13 refs., 24 figs

  1. Pinhole SPECT: high resolution imaging of brain tumours in small laboratory animals

    International Nuclear Information System (INIS)

    Franceschim, M.; Bokulic, T.; Kusic, Z.; Strand, S.E.; Erlandsson, K.

    1994-01-01

    The performance properties of pinhole SPECT and the application of this technology to evaluate radionuclide uptake in brain in small laboratory animals were investigated. System sensitivity and spatial resolution measurements of a rotating scintillation camera system were made for a low energy pinhole collimator equipped with 2.0 mm aperture pinhole insert. Projection data were acquired at 4 degree increments over 360 degrees in the step and shoot mode using a 4.5 cm radius of rotation. Pinhole planar and SPECT imaging were obtained to evaluate regional uptake of Tl-201, Tc-99m-MIBI, Tc-99m-HMPAO and Tc-99m-DTPA in tumor and control regions of the brain in a primary brain tumor model in Fisher 344 rats. Pinhole SPECT images were reconstructed using a modified cone- beam algorithm developed from a two dimensional fan-beam filtered backprojection algorithm. The reconstructed transaxial resolution of 2.8 FWHM and system sensitivity of 0.086 c/s/kBq with the 2.0 mm pinhole collimator aperture were measured. Tumor to non-tumor uptake ratios at 19-28 days post tumor cell inoculation varied by a factor > 20:1 on SPECT images. Pinhole SPECT provides an important new approach for performing high resolution imaging: the resolution properties of pinhole SPECT are superior to those which have been achieved with conventional SPECT or PET imaging technologies. (author)

  2. Feasibility study on X-ray source with pinhole imaging method

    International Nuclear Information System (INIS)

    Qiu Rui; Li Junli

    2007-01-01

    In order to verify the feasibility of study on X-ray source with pinhole imaging method, and optimize the design of X-ray pinhole imaging system, an X-ray pinhole imaging equipment was set up. The change of image due to the change of the position and intensity of X-ray source was estimated with mathematical method and validated with experiment. The results show that the change of the spot position and gray of the spot is linearly related with the change of the position and intensity of X-ray source, so it is feasible to study X-ray source with pinhole imaging method in this application. The results provide some references for the design of X-ray pinhole imaging system. (authors)

  3. Emulation and design of terahertz reflection-mode confocal scanning microscopy based on virtual pinhole

    Science.gov (United States)

    Yang, Yong-fa; Li, Qi

    2014-12-01

    In the practical application of terahertz reflection-mode confocal scanning microscopy, the size of detector pinhole is an important factor that determines the performance of spatial resolution characteristic of the microscopic system. However, the use of physical pinhole brings some inconvenience to the experiment and the adjustment error has a great influence on the experiment result. Through reasonably selecting the parameter of matrix detector virtual pinhole (VPH), it can efficiently approximate the physical pinhole. By using this approach, the difficulty of experimental calibration is reduced significantly. In this article, an imaging scheme of terahertz reflection-mode confocal scanning microscopy that is based on the matrix detector VPH is put forward. The influence of detector pinhole size on the axial resolution of confocal scanning microscopy is emulated and analyzed. Then, the parameter of VPH is emulated when the best axial imaging performance is reached.

  4. MVP: a microbe-phage interaction database.

    Science.gov (United States)

    Gao, Na L; Zhang, Chengwei; Zhang, Zhanbing; Hu, Songnian; Lercher, Martin J; Zhao, Xing-Ming; Bork, Peer; Liu, Zhi; Chen, Wei-Hua

    2018-01-04

    Phages invade microbes, accomplish host lysis and are of vital importance in shaping the community structure of environmental microbiota. More importantly, most phages have very specific hosts; they are thus ideal tools to manipulate environmental microbiota at species-resolution. The main purpose of MVP (Microbe Versus Phage) is to provide a comprehensive catalog of phage-microbe interactions and assist users to select phage(s) that can target (and potentially to manipulate) specific microbes of interest. We first collected 50 782 viral sequences from various sources and clustered them into 33 097 unique viral clusters based on sequence similarity. We then identified 26 572 interactions between 18 608 viral clusters and 9245 prokaryotes (i.e. bacteria and archaea); we established these interactions based on 30 321 evidence entries that we collected from published datasets, public databases and re-analysis of genomic and metagenomic sequences. Based on these interactions, we calculated the host range for each of the phage clusters and accordingly grouped them into subgroups such as 'species-', 'genus-' and 'family-' specific phage clusters. MVP is equipped with a modern, responsive and intuitive interface, and is freely available at: http://mvp.medgenius.info. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  5. Characterizing Phage Genomes for Therapeutic Applications

    Directory of Open Access Journals (Sweden)

    Casandra W. Philipson

    2018-04-01

    Full Text Available Multi-drug resistance is increasing at alarming rates. The efficacy of phage therapy, treating bacterial infections with bacteriophages alone or in combination with traditional antibiotics, has been demonstrated in emergency cases in the United States and in other countries, however remains to be approved for wide-spread use in the US. One limiting factor is a lack of guidelines for assessing the genomic safety of phage candidates. We present the phage characterization workflow used by our team to generate data for submitting phages to the Federal Drug Administration (FDA for authorized use. Essential analysis checkpoints and warnings are detailed for obtaining high-quality genomes, excluding undesirable candidates, rigorously assessing a phage genome for safety and evaluating sequencing contamination. This workflow has been developed in accordance with community standards for high-throughput sequencing of viral genomes as well as principles for ideal phages used for therapy. The feasibility and utility of the pipeline is demonstrated on two new phage genomes that meet all safety criteria. We propose these guidelines as a minimum standard for phages being submitted to the FDA for review as investigational new drug candidates.

  6. Characterizing Phage Genomes for Therapeutic Applications.

    Science.gov (United States)

    Philipson, Casandra W; Voegtly, Logan J; Lueder, Matthew R; Long, Kyle A; Rice, Gregory K; Frey, Kenneth G; Biswas, Biswajit; Cer, Regina Z; Hamilton, Theron; Bishop-Lilly, Kimberly A

    2018-04-10

    Multi-drug resistance is increasing at alarming rates. The efficacy of phage therapy, treating bacterial infections with bacteriophages alone or in combination with traditional antibiotics, has been demonstrated in emergency cases in the United States and in other countries, however remains to be approved for wide-spread use in the US. One limiting factor is a lack of guidelines for assessing the genomic safety of phage candidates. We present the phage characterization workflow used by our team to generate data for submitting phages to the Federal Drug Administration (FDA) for authorized use. Essential analysis checkpoints and warnings are detailed for obtaining high-quality genomes, excluding undesirable candidates, rigorously assessing a phage genome for safety and evaluating sequencing contamination. This workflow has been developed in accordance with community standards for high-throughput sequencing of viral genomes as well as principles for ideal phages used for therapy. The feasibility and utility of the pipeline is demonstrated on two new phage genomes that meet all safety criteria. We propose these guidelines as a minimum standard for phages being submitted to the FDA for review as investigational new drug candidates.

  7. Possible application of nonredundant pinhole arrays to fuel pin imaging

    International Nuclear Information System (INIS)

    Berzins, G.J.; Han, K.S.

    1975-11-01

    LMFBR Safety Test Facility imaging experiments rely on emission of radiation by the fuel pins and thus appear to strongly complement radiographic techniques in that they are most employable during peak excursion--a time of least favorable radiographic signal--to--noise ratio. Radiography, on the other hand, can provide information long before or after the excursion--times of below threshold signal for direct imaging techniques. An underlying premise of any imaging experiment is that, in addition to sufficient brightness, sufficient contrast exists in the scene. A further restriction is imposed by intervening materials, such as the wall of a containment vessel, that not only absorb but also scatter the radiation. These questions are approached by examining the properties of potential recording instrumentation, of pinhole apertures, and of the necessary radiation sources

  8. Fresnel's phase observation by means of the pinhole Young's experiment

    International Nuclear Information System (INIS)

    Medina, F.F.; Matteucci, G.

    2000-04-01

    Using the conventional Young's experiment with two pinholes, we observe the shift effect of the Fresnel's phase on the interference patterns, by measuring its intensity on the optical axis. It allows us to propose a criterion for distinguishing between Fraunhofer and Fresnel diffraction. Indeed, in the Fraunhofer domain the Young's patterns will be centered on the optical axis. As a consequence, only constructive interference will occur at this point. But in the Fresnel domain, the Young's patterns will be laterally shifted in such a way that constructive and destructive interference will occur alternatively on the optical axis, and the intensity of the diffraction pattern at this point will oscillate. Extended diffracting apertures can be analyzed as ensembles of Young's pairs of wavelet sources. From this point of view, the intensity distribution they produce on the detector plane results from the superposition of all their interference patterns. (author)

  9. Pinhole imaging in Legg--Perthes disease: further observations

    International Nuclear Information System (INIS)

    Danigelis, J.A.

    1976-01-01

    Fifty-nine patients with Legg--Perthes disease and 12 others were studied using /sup 99m/Tc-polyphosphate and the pinhole collimator imaging technique. Radiographs of both hips were correlated with images in each patient. In the Legg--Perthes patients, a radionuclide uptake deficiency of variable size was observed in the proximal femoral epiphysis (EOC), which we believe is related to varying degrees of impaired blood supply. During later disease stages, adjacent zones of increased radio-nuclide activity or revascularization were observed that would replace the uptake defect eventually. Unless radiographic evidence of new bone formation was observed in the EOC, it was impossible to predict either the presence or extent of revascularization until bone imaging was done. Those patients with revascularization activity in the EOC exhibited a relatively short time interval (average, 3.2 months) before evidence of new bone formation radiographically. Others with increased radionuclide concentration limited to the growth plate and/or metaphysis averaged a much longer 7.8 months. In two patients there was a reversal of the initially increased activity in the growth plate, suggesting another vascular insult. There were no false-negative bone-image findings in the 12 cases that clinically and/or radiologically simulated Legg-Perthes disease. Our image studies correlate well with published histopathologic investigations, indicating to us that assessment of extent of pathologic involvement and of the disease course is facilitated by this technique. Subsequently, this could influence treatment selection and provide a more objective baseline from which to judge treatment results. Continued experience suggests pinhole bone imaging has useful clinical application in Legg--Perthes disease and other childhood hip disorders

  10. Pinhole imaging in Legg-Perthes disease: further observations.

    Science.gov (United States)

    Danigelis, J A

    1976-01-01

    Fifty-nine patients with Legg-Perthes disease and 12 others were studied using 99mTc-polyphosphate and the pinhole collimator imaging technique. Radiographs of both hips were correlated with images in each patient. In the Legg-Perthes patients, a radionuclide uptake deficiency of variable size was observed in the proximal femoral epiphysis (EOC), which we believe is related to varying degrees of impaired blood supply. During later disease stages, adjacent zones of increased radionuclide activity of revascularization were observed that would replace the uptake defect eventually. Unless radiographic evidence of new bone formation was observed in the EOC, it was impossible to predict either the presence or extent of revascularization until bone imaging was done. Those patients with revascularization activity in the EOC exhibited a relatively short time interval (average, 3.2 months) before evidence of new bone formation radiographically. Others with increased radionuclide concentration limited to the growth plate and/or metaphysis averaged a much longer 7.8 months. In two patients there was a reversal of the initially increased activity in the growth plate, suggesting another vascular insult. There were no false-negative bone-image findings in the 12 cases that clinically and/or radiologically simulated Legg-Perthes disease. Our image studies correlate well with published histopathologic investigations, indicating to us that assessment of extent of pathologic involvement and of the disease course is facilitated by this technique. Subsequently, this could influence treatment selection and provide a more objective baseline from which to judge treatment results. Continued experience suggests pinhole bone imaging has useful clinical application in Legg-Perthes disease and other childhood hip disorders.

  11. Antibody production in response to staphylococcal MS-1 phage cocktail in patients undergoing phage therapy

    Directory of Open Access Journals (Sweden)

    Maciej Żaczek

    2016-10-01

    Full Text Available In this study, we investigated the humoral immune response (through the release of IgG, IgA, and IgM antiphage antibodies to a staphylococcal phage cocktail in patients undergoing experimental phage therapy at the Phage Therapy Unit, Medical Center of the Ludwik Hirszfeld Institute of Immunology and Experimental Therapy in Wrocław, Poland. We also evaluated whether occurring antiphage antibodies had neutralizing properties towards applied phages (K rate. Among 20 examined patients receiving the MS-1 phage cocktail orally and/or locally, the majority did not show a noticeably higher level of antiphage antibodies in their sera during phage administration. Even in those individual cases with an increased immune response, mostly by induction of IgG and IgM, the presence of antiphage antibodies did not translate into unsatisfactory clinical results of phage therapy. On the other hand, a negative outcome of the treatment occurred in some patients who showed relatively weak production of antiphage antibodies before and during treatment. This may imply that possible induction of antiphage antibodies is not an obstacle to the implementation of phage therapy and support our assumption that the outcome of the phage treatment does not primarily depend on the appearance of antiphage antibodies in sera of patients during therapy. These conclusions are in line with our previous findings. The confirmation of this thesis is of great interest as regards the efficacy of phage therapy in humans.

  12. Antibody Production in Response to Staphylococcal MS-1 Phage Cocktail in Patients Undergoing Phage Therapy.

    Science.gov (United States)

    Żaczek, Maciej; Łusiak-Szelachowska, Marzanna; Jończyk-Matysiak, Ewa; Weber-Dąbrowska, Beata; Międzybrodzki, Ryszard; Owczarek, Barbara; Kopciuch, Agnieszka; Fortuna, Wojciech; Rogóż, Paweł; Górski, Andrzej

    2016-01-01

    In this study, we investigated the humoral immune response (through the release of IgG, IgA, and IgM antiphage antibodies) to a staphylococcal phage cocktail in patients undergoing experimental phage therapy at the Phage Therapy Unit, Medical Center of the Ludwik Hirszfeld Institute of Immunology and Experimental Therapy in Wrocław, Poland. We also evaluated whether occurring antiphage antibodies had neutralizing properties toward applied phages (K rate). Among 20 examined patients receiving the MS-1 phage cocktail orally and/or locally, the majority did not show a noticeably higher level of antiphage antibodies in their sera during phage administration. Even in those individual cases with an increased immune response, mostly by induction of IgG and IgM, the presence of antiphage antibodies did not translate into unsatisfactory clinical results of phage therapy. On the other hand, a negative outcome of the treatment occurred in some patients who showed relatively weak production of antiphage antibodies before and during treatment. This may imply that possible induction of antiphage antibodies is not an obstacle to the implementation of phage therapy and support our assumption that the outcome of the phage treatment does not primarily depend on the appearance of antiphage antibodies in sera of patients during therapy. These conclusions are in line with our previous findings. The confirmation of this thesis is of great interest as regards the efficacy of phage therapy in humans.

  13. Therapeutic use of chimeric bacteriophage (phage) lysins in staphylococcal endophthalmitis

    Science.gov (United States)

    Purpose: Phage endolysins are peptidoglycan hydrolases that are produced at the end of the phage lytic cycle to digest the host bacterial cell wall, facilitating the release of mature phage progeny. The aim of this study is to determine the antimicrobial activity of chimeric phage lysins against cli...

  14. Phage Therapy -- Everything Old Is New again

    Directory of Open Access Journals (Sweden)

    Andrew M Kropinski

    2006-01-01

    Full Text Available The study of bacterial viruses (bacteriophages or phages proved pivotal in the nascence of the disciplines of molecular biology and microbial genetics, providing important information on the central processes of the bacterial cell (DNA replication, transcription and translation and on how DNA can be transferred from one cell to another. As a result of the pioneering genetics studies and modern genomics, it is now known that phages have contributed to the evolution of the microbial cell and to its pathogenic potential. Because of their ability to transmit genes, phages have been exploited to develop cloning vector systems. They also provide a plethora of enzymes for the modern molecular biologist. Until the introduction of antibiotics, phages were used to treat bacterial infections (with variable success. Western science is now having to re-evaluate the application of phage therapy -- a therapeutic modality that never went out of vogue in Eastern Europe -- because of the emergence of an alarming number of antibiotic-resistant bacteria. The present article introduces the reader to phage biology, and the benefits and pitfalls of phage therapy in humans and animals.

  15. Development of a phage typing system for Staphylococcus hyicus

    DEFF Research Database (Denmark)

    Wegener, Henrik Caspar

    1993-01-01

    Bacteriophages were released by 98% of 100 Staphylococcus hyicus strains studied after treatment with mitomycin C. Twenty-three phages with different lytic spectra were included in a phage typing system and used f or typing S. hyicus. On a test-set of 100 epidemiologically unrelated S. hyicus...... strains isolated from Danish pig herds, the phages were able to type 92% of the strains, producing 16 different phage types. Reproducibility of the phage typing system after subculture of the strains and using fresh phage stock was 96%. Typability ranged from 52 to 80% when typing porcine strains...... originating from other countries. Although phages were isolated from porcine skin strains exclusively, the system produced phage types in S. hyicus strains of bovine origin. Ten strains of S. aureus and S. chromogenes were not typable by these phages. Strains belonging to one phage type (A/B/C/W) were...

  16. Complete genome sequence of Vibrio anguillarum phage CHOED successfully used for phage therapy in aquaculture

    DEFF Research Database (Denmark)

    Romero, Jaime; Higuera, Gastón; Gajardo, Felipe

    2014-01-01

    Vibrio anguillarum phage CHOED was isolated from Chilean mussels. It is a virulent phage showing effective inhibition of V. anguillarum. CHOED has potential in phage therapy, because it can protect fish from vibriosis in fish farms. Here, we announce the completely sequenced genome of V....... anguillarum phage CHOED....

  17. Imaging of fast-neutron sources using solid-state track-recorder pinhole radiography

    International Nuclear Information System (INIS)

    Ruddy, F.H.; Gold, R.; Roberts, J.H.; Kaiser, B.J.; Preston, C.C.

    1983-08-01

    Pinhole imaging methods are being developed and tested for potential future use in imaging the intense neutron source of the Fusion Materials Irradiation Test (FMIT) Facility. Previously reported, extensive calibration measurements of the proton, neutron, and alpha particle response characteristics of CR-39 polymer solid state track recorders (SSTRs) are being used to interpret the results of imaging experiments using both charged particle and neutron pinhole collimators. High resolution, neutron pinhole images of a 252 Cf source have been obtained in the form of neutron induced proton recoil tracks in CR-39 polymer SSTR. These imaging experiments are described as well as their potential future applications to FMIT

  18. Heat tolerance of dairy lactococcal c2 phages

    DEFF Research Database (Denmark)

    Nielsen, Cecilie Lykke Marvig; Basheer, Aideh; Neve, H.

    2011-01-01

    -order kinetics with correlation coefficients of 0.96–0.99. D70-values of 12 s and 16.6 min were calculated for the most sensitive and resistant phage, respectively. Release of phage DNA from capsids, and disintegration of phage heads and tails were among the first morphological changes observed for moderately...... thermal inactivated lysates (15% phage inactivation) of the heat tolerant phage P635....

  19. [Isolation and characterization of siphovirus phages infecting bovine Streptococcus agalactiae].

    Science.gov (United States)

    Bai, Qinqin; Yang, Yongchun; Lu, Chengping

    2016-02-04

    To isolate and identify Streptococcus agalactiae phages and screen candidate phages to control infection caused by bovine S. agalactiae. We used two methods for isolation of S. agalactiae phages, namely (1) isolation of phages from milk and environmental samples, and (2) isolation of phages via induction of lysogens with Mitomycin C. Double-layer agar culture method was used to purify phages. Then the newly obtained phages, with S. agalactiae phage JX01 isolated from mastitis milk, were comparatively analyzed in the following aspects: morphology of phages by transmission electron microscopy, host range of phages to 55 S. agalactiae strains and other Streptococcus strains, phages DNA using EcoR I, Xba I, Pst I and Sal I, the optical multiplicity of infection, absorption curve and one step growth curve, and the stability of phages at different storage conditions. The comparative analysis of the 3 novel phages LYGO9, HZ04 and pA11 (induced from S. agalctiae bovine clinical isolate HAJL2011070601) with JX01 showed that the 4 phages were classified as the member of Siphovirdae family. EcoR I, Sal I, Xba I and Pst I separately digested the 4 phages DNA provided 4, 3, 3 and 2 profiles, respectively. This suggested that they were different strains. All the 4 phages specifically infected bovine S. agalactiae isolates. LYGO9, pA11, JX01 and HZ04 could lyse 12, 13, 20 and 23 of 42 tested bovine S. agalctiae isolates, respectively. This clearly indicated that these 4 phages are closely related. The 3 new phages which specifically lyse bovine S. agalactiae isolates are siphovirus phages. Phage LYGO9 was shown having a short latent period and a larger burst size.

  20. Pyrimidine dimers are not the principal pre-mutagenic lesions induced in lambda phage DNA by ultraviolet light

    International Nuclear Information System (INIS)

    Wood, R.D.

    1985-01-01

    Experiments were performed to examine the role of cyclobutyl pyrimidine dimers in the process of mutagenesis by ultraviolet light. Lambda phage DNA was irradiated with u.v. and then incubated with an Escherichia coli photoreactivating enzyme, which monomerizes cyclobutyl pyrimidine dimers upon exposure to visible light. The photoreactivated DNA was packaged into lambda phage particles, which were used to infect E. coli uvr - host cells that had been induced for SOS functions by ultraviolet irradiation. Photoreactivation removed most toxic lesions from irradiated phage, but did not change the frequency of induction of mutations to the clear-plaque phenotype. This implies that cyclobutyl pyrimidine dimers can be lethal, but usually do not serve as sites of mutations in the phage. The DNA sequences of mutants, derived from photoreactivated DNA showed that almost two-thirds (16/28) were transitions, the same fraction found for u.v. mutagenesis without photoreactivation. Thus the lesion inducing transitions is not the cyclobutyl pyrimidine dimer. Photoreactivation of SOS-induced host cells before infection with u.v.-irradiated phage reduced mutagenesis substantially. In this case, photoreversal of cyclobutyl dimers serves to reduce expression of the SOS functions that are required in targeted u.v. mutagenesis. (author)

  1. Three New Escherichia coli Phages from the Human Gut Show Promising Potential for Phage Therapy.

    Directory of Open Access Journals (Sweden)

    Marion Dalmasso

    Full Text Available With the emergence of multi-drug resistant bacteria the use of bacteriophages (phages is gaining renewed interest as promising anti-microbial agents. The aim of this study was to isolate and characterize phages from human fecal samples. Three new coliphages, ɸAPCEc01, ɸAPCEc02 and ɸAPCEc03, were isolated. Their phenotypic and genomic characteristics, and lytic activity against biofilm, and in combination with ciprofloxacin, were investigated. All three phages reduced the growth of E. coli strain DPC6051 at multiplicity of infection (MOI between 10-3 and 105. A cocktail of all three phages completely inhibited the growth of E. coli. The phage cocktail also reduced biofilm formation and prevented the emergence of phage-resistant mutants which occurred with single phage. When combined with ciprofloxacin, phage alone or in cocktail inhibited the growth of E. coli and prevented the emergence of resistant mutants. These three new phages are promising biocontrol agents for E. coli infections.

  2. Lethal modifications of DNA via the transmutation of 32P and 33P incorporated in the genome of the S13 bacteriophage

    International Nuclear Information System (INIS)

    Cols, P.; Apelgot, S.; Guille, E.

    1988-01-01

    When circular single-standard DNA of phage S13 is labelled with 32 P or 33 P, the transmutations very efficiently bring about a loss of phage infectiousness (efficiency = 1 for 32 P and 0.73 for 33 P). For both radionuclides, the lethal efficiencies as well as the lethal events are different. In the case of 32 P, the lethal event is the loss of the circular integrity of the DNA molecule, occurring as a consequence of a systematic single strand-break caused by each 32 P decay (100%). Conversely, in the case of 33 P, the lethal events are either a single strand-break (40%) or a local stereochemical modification (33%). The same primary event, the substitution at each 33 P decay of a phosphate by a sulfate molecule, leads to one of these lethal events in relation to the decay site. Moreover, neither the phage adsorption nor its genome injection into bacteria depends on the physical state of the genome, and thus lethality is revealed at only the genetic level. (orig.)

  3. A study of the decoding of multiple pinhole coded aperture RI tomographic images

    International Nuclear Information System (INIS)

    Hasegawa, Takeo; Kobayashi, Akitoshi; Nishiyama, Yutaka

    1980-01-01

    The authors constructed a Multiple Pinhole Coded Aperture (MPCA) and developed related decoding software. When simple coordinate transformation was performed, omission of points and shifting of counts occurred. By selecting various tomographic planes and collecting count for each tomographic depth from the shadowgram, a solution to these problems was found. The counts from the central portion of the tomographic image from the MPCA were incorrectly high, this was rectified by a correction function to improve the uniformity correction program of the γ-camera. Depth resolution of the tomographic image improved in proportion to the area encompassed by the pinhole configuration. An MPCA with a uniform arrangement of pinholes (e, g, pinholes in an arrangement parallel to the X-axis or the Y-axis) yielded decoded tomographic images of inferior quality. Optimum results were obtained with a ring-shaped arrangement yielding clinically applicable tomographic images even for large objects. (author)

  4. Time resolved x-ray pinhole photography of compressed laser fusion targets

    International Nuclear Information System (INIS)

    Attwood, D.T.

    1976-01-01

    Use of the Livermore x-ray streak camera to temporally record x-ray pinhole images of laser compressed targets is described. Use is made of specially fabricated composite x-ray pinholes which are near diffraction limited for 6 A x-rays, but easily aligned with a He--Ne laser of 6328 A wavelength. With a 6 μm x-ray pinhole, the overall system can be aligned to 5 μm accuracy and provides implosion characteristics with space--time resolutions of approximately 6 μm and 15 psec. Acceptable criteria for pinhole alignment, requisite x-ray flux, and filter characteristics are discussed. Implosion characteristics are presented from our present experiments with 68 μm diameter glass microshell targets and 0.45 terawatt, 70 psec Nd laser pulses. Final implosion velocities in excess of 3 x 10 7 cm/sec are evident

  5. Pinhole Breaches in Spent Fuel Containers: Improvements to Conservative Models of Aerosol Release and Plugging

    International Nuclear Information System (INIS)

    Casella, Andrew M.; Loyalka, Sudarsham K.; Hanson, Brady D.

    2007-01-01

    By taking the differential forms of transport and equations of state, the equations describing aerosol transport in pinhole breaches can be solved directly using continuous models. The results are compared with discrete models.

  6. Plugging Effects on Depressurization Time in Dry Storage Containers with Pinhole Breaches

    International Nuclear Information System (INIS)

    Casella, Andrew M.; LOYALKA, SUDARSHAN K.; Hanson, Brady D.

    2006-01-01

    As continuation on previous work, we now examine the effect that aerosol deposition may have on plugging pinhole breaches in spent fuel containers. A model is developed considering only diffusive settling

  7. Studies of closure phenomena in pinholes irradiated by Nd laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Auerbach, J.M.; Holmes, N.C.; Hunt, J.T.; Linford, G.J.

    1978-08-21

    The plasma closure of spatial filter pinholes is a critical parameter in the performance of high energy glass laser systems. Using 50 to 100 J, 300 psec FWHM laser pulses on the Janus laser, an investigation has been made on closure effects in 300 ..mu..m to 500 ..mu..m diameter pinholes of various materials and thicknesses. Calorimetry measurements have yielded data on pinhole transmission and intensity loading on the periphery of the pinhole. Ultrafast streak photography measurements indicate effective closure velocities of 2 x 10/sup 7/ cm/sec to 5 x 10/sup 7/ cm/sec. Scattered light measurements have shown the transmission loss through a typical spatial filter configuration to be primarily refractive in nature.

  8. Studies of closure phenomena in pinholes irradiated by Nd laser pulses

    International Nuclear Information System (INIS)

    Auerbach, J.M.; Holmes, N.C.; Hunt, J.T.; Linford, G.J.

    1978-01-01

    The plasma closure of spatial filter pinholes is a critical parameter in the performance of high energy glass laser systems. Using 50 to 100 J, 300 psec FWHM laser pulses on the Janus laser, an investigation has been made on closure effects in 300 μm to 500 μm diameter pinholes of various materials and thicknesses. Calorimetry measurements have yielded data on pinhole transmission and intensity loading on the periphery of the pinhole. Ultrafast streak photography measurements indicate effective closure velocities of 2 x 10 7 cm/sec to 5 x 10 7 cm/sec. Scattered light measurements have shown the transmission loss through a typical spatial filter configuration to be primarily refractive in nature

  9. Phage Lambda P Protein: Trans-Activation, Inhibition Phenotypes and their Suppression

    Science.gov (United States)

    Hayes, Sidney; Erker, Craig; Horbay, Monique A.; Marciniuk, Kristen; Wang, Wen; Hayes, Connie

    2013-01-01

    The initiation of bacteriophage λ replication depends upon interactions between the oriλ DNA site, phage proteins O and P, and E. coli host replication proteins. P exhibits a high affinity for DnaB, the major replicative helicase for unwinding double stranded DNA. The concept of P-lethality relates to the hypothesis that P can sequester DnaB and in turn prevent cellular replication initiation from oriC. Alternatively, it was suggested that P-lethality does not involve an interaction between P and DnaB, but is targeted to DnaA. P-lethality is assessed by examining host cells for transformation by ColE1-type plasmids that can express P, and the absence of transformants is attributed to a lethal effect of P expression. The plasmid we employed enabled conditional expression of P, where under permissive conditions, cells were efficiently transformed. We observed that ColE1 replication and plasmid establishment upon transformation is extremely sensitive to P, and distinguish this effect from P-lethality directed to cells. We show that alleles of dnaB protect the variant cells from P expression. P-dependent cellular filamentation arose in ΔrecA or lexA[Ind-] cells, defective for SOS induction. Replication propagation and restart could represent additional targets for P interference of E. coli replication, beyond the oriC-dependent initiation step. PMID:23389467

  10. Supersize me: Cronobacter sakazakii phage GAP32

    Energy Technology Data Exchange (ETDEWEB)

    Abbasifar, Reza; Griffiths, Mansel W. [Canadian Research Institute for Food Safety, University of Guelph, Guelph, ON, Canada N1G 2W1 (Canada); Sabour, Parviz M. [Agriculture and Agri-Food Canada, Guelph Food Research Centre, Guelph, ON, Canada N1G 5C9 (Canada); Ackermann, Hans-Wolfgang [Department of Microbiology-Infectiology and Immunology, Faculty of Medicine, Université Laval, Quebec, QC (Canada); Vandersteegen, Katrien; Lavigne, Rob [Laboratory of Gene Technology, Katholieke Universiteit Leuven, Leuven (Belgium); Noben, Jean-Paul [Biomedical Research Institute and Transnational University Limburg, School of Life Sciences, Hasselt University, Diepenbeek (Belgium); Alanis Villa, Argentina; Abbasifar, Arash [Canadian Research Institute for Food Safety, University of Guelph, Guelph, ON, Canada N1G 2W1 (Canada); Nash, John H.E. [Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, Guelph, ON, Canada N1G 3W4 (Canada); Kropinski, Andrew M., E-mail: akropins@uoguelph.ca [Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, Guelph, ON, Canada N1G 3W4 (Canada); Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada N1G 2W1 (Canada)

    2014-07-15

    Cronobacter sakazakii is a Gram-negative pathogen found in milk-based formulae that causes infant meningitis. Bacteriophages have been proposed to control bacterial pathogens; however, comprehensive knowledge about a phage is required to ensure its safety before clinical application. We have characterized C. sakazakii phage vB{sub C}saM{sub G}AP32 (GAP32), which possesses the second largest sequenced phage genome (358,663 bp). A total of 571 genes including 545 protein coding sequences and 26 tRNAs were identified, thus more genes than in the smallest bacterium, Mycoplasma genitalium G37. BLASTP and HHpred searches, together with proteomic analyses reveal that only 23.9% of the putative proteins have defined functions. Some of the unique features of this phage include: a chromosome condensation protein, two copies of the large subunit terminase, a predicted signal-arrest-release lysin; and an RpoD-like protein, which is possibly involved in the switch from immediate early to delayed early transcription. Its closest relatives are all extremely large myoviruses, namely coliphage PBECO4 and Klebsiella phage vB{sub K}leM-RaK2, with whom it shares approximately 44% homologous proteins. Since the homologs are not evenly distributed, we propose that these three phages belong to a new subfamily. - Highlights: • Cronobacter sakazakii phage vB{sub C}saM{sub G}AP32 has a genome of 358,663 bp. • It encodes 545 proteins which is more than Mycoplasma genitalium G37. • It is a member of the Myoviridae. • It is peripherally related to coliphage PBECO4 and Klebsiella phage vB{sub K}leM-RaK2. • GAP32 encodes a chromosome condensation protein.

  11. Complete Genome Sequences of 44 Arthrobacter Phages.

    Science.gov (United States)

    Klyczek, Karen K; Jacobs-Sera, Deborah; Adair, Tamarah L; Adams, Sandra D; Ball, Sarah L; Benjamin, Robert C; Bonilla, J Alfred; Breitenberger, Caroline A; Daniels, Charles J; Gaffney, Bobby L; Harrison, Melinda; Hughes, Lee E; King, Rodney A; Krukonis, Gregory P; Lopez, A Javier; Monsen-Collar, Kirsten; Pizzorno, Marie C; Rinehart, Claire A; Staples, Amanda K; Stowe, Emily L; Garlena, Rebecca A; Russell, Daniel A; Cresawn, Steven G; Pope, Welkin H; Hatfull, Graham F

    2018-02-01

    We report here the complete genome sequences of 44 phages infecting Arthrobacter sp. strain ATCC 21022. These phages have double-stranded DNA genomes with sizes ranging from 15,680 to 70,707 bp and G+C contents from 45.1% to 68.5%. All three tail types (belonging to the families Siphoviridae , Myoviridae , and Podoviridae ) are represented. Copyright © 2018 Klyczek et al.

  12. Patient restraining device for the pinhole collimator and gamma scintillation camera

    International Nuclear Information System (INIS)

    Kay, T.D.

    1977-01-01

    A patient restraining device for use with the pinhole collimator of a conventional Gamma Scintillation Camera, the restraining device being made of an adapter ring and a patient holder. The adapter ring is secured directly to the pinhole collimator while the holder is adjustably mounted on the adapter. The adapter ring is so designed to accommodate a variety of holders so as to enable the scanning of many different areas of a patient's anatomy by the scintillation camera

  13. Depth-of-Interaction Compensation Using a Focused-Cut Scintillator for a Pinhole Gamma Camera

    OpenAIRE

    Alhassen, Fares; Kudrolli, Haris; Singh, Bipin; Kim, Sangtaek; Seo, Youngho; Gould, Robert G.; Nagarkar, Vivek V.

    2011-01-01

    Preclinical SPECT offers a powerful means to understand the molecular pathways of drug interactions in animal models by discovering and testing new pharmaceuticals and therapies for potential clinical applications. A combination of high spatial resolution and sensitivity are required in order to map radiotracer uptake within small animals. Pinhole collimators have been investigated, as they offer high resolution by means of image magnification. One of the limitations of pinhole geometries is ...

  14. High-speed photography of light beams transmitted through pinhole targets

    International Nuclear Information System (INIS)

    Yaonan, D.; Haien, He.; Lian, C.; Huifang, Z.; Zhijian, Z.

    1988-01-01

    A method of high speed photography is presented. It was designed and performed in order to study temporal behaviors of plasma closure effects of pinhole targets in laser plasma experiments. A series of high speed photographs were taken for the laser beam transmitted through the pinhole targets. Spatially resolved and integrated temporal histories of closure effects were observed, respectively. Some physical information about closure effect and closure speed have been studied

  15. The Staphylococci Phages Family: An Overview

    Directory of Open Access Journals (Sweden)

    Laurence Van Melderen

    2012-11-01

    Full Text Available Due to their crucial role in pathogenesis and virulence, phages of Staphylococcus aureus have been extensively studied. Most of them encode and disseminate potent staphylococcal virulence factors. In addition, their movements contribute to the extraordinary versatility and adaptability of this prominent pathogen by improving genome plasticity. In addition to S. aureus, phages from coagulase-negative Staphylococci (CoNS are gaining increasing interest. Some of these species, such as S. epidermidis, cause nosocomial infections and are therefore problematic for public health. This review provides an overview of the staphylococcal phages family extended to CoNS phages. At the morphological level, all these phages characterized so far belong to the Caudovirales order and are mainly temperate Siphoviridae. At the molecular level, comparative genomics revealed an extensive mosaicism, with genes organized into functional modules that are frequently exchanged between phages. Evolutionary relationships within this family, as well as with other families, have been highlighted. All these aspects are of crucial importance for our understanding of evolution and emergence of pathogens among bacterial species such as Staphylococci.

  16. Comparison of fan beam, slit-slat and multi-pinhole collimators for molecular breast tomosynthesis.

    Science.gov (United States)

    van Roosmalen, Jarno; Beekman, Freek J; Goorden, Marlies C

    2018-05-16

    Recently, we proposed and optimized dedicated multi-pinhole molecular breast tomosynthesis (MBT) that images a lightly compressed breast. As MBT may also be performed with other types of collimators, the aim of this paper is to optimize MBT with fan beam and slit-slat collimators and to compare its performance to that of multi-pinhole MBT to arrive at a truly optimized design. Using analytical expressions, we first optimized fan beam and slit-slat collimator parameters to reach maximum sensitivity at a series of given system resolutions. Additionally, we performed full system simulations of a breast phantom containing several tumours for the optimized designs. We found that at equal system resolution the maximum achievable sensitivity increases from pinhole to slit-slat to fan beam collimation with fan beam and slit-slat MBT having on average a 48% and 20% higher sensitivity than multi-pinhole MBT. Furthermore, by inspecting simulated images and applying a tumour-to-background contrast-to-noise (TB-CNR) analysis, we found that slit-slat collimators underperform with respect to the other collimator types. The fan beam collimators obtained a similar TB-CNR as the pinhole collimators, but the optimum was reached at different system resolutions. For fan beam collimators, a 6-8 mm system resolution was optimal in terms of TB-CNR, while with pinhole collimation highest TB-CNR was reached in the 7-10 mm range.

  17. Histopathological effects of lethal and sub-lethal concentrations of ...

    African Journals Online (AJOL)

    The histopathological effects of lethal and sub-lethal concentrations of glyphosate on African catfish Clarias gariepinus were investigated. C. gariepinus juveniles were assessed in a static renewal bioassay for 96 hours (acute toxicity) and 28 days (chronic toxicity) using varying concentrations (0.0 mg/l 20.0 mg/l, 30.0 mg/l, ...

  18. Colonisation of a phage susceptible Campylobacter jejuni population in two phage positive broiler flocks.

    Directory of Open Access Journals (Sweden)

    Sophie Kittler

    Full Text Available The pathogens Campylobacter jejuni and Campylobacter coli are commensals in the poultry intestine and campylobacteriosis is one of the most frequent foodborne diseases in developed and developing countries. Phages were identified to be effective in reducing intestinal Campylobacter load and this was evaluated, in the first field trials which were recently carried out. The aim of this study was to further investigate Campylobacter population dynamics during phage application on a commercial broiler farm. This study determines the superiority in colonisation of a Campylobacter type found in a field trial that was susceptible to phages in in vitro tests. The colonisation factors, i.e. motility and gamma glutamyl transferase activity, were increased in this type. The clustering in phylogenetic comparisons of MALDI-TOF spectra did not match the ST, biochemical phenotype and phage susceptibility. Occurrence of Campylobacter jejuni strains and phage susceptibility types with different colonisation potential seem to play a very important role in the success of phage therapy in commercial broiler houses. Thus, mechanisms of both, phage susceptibility and Campylobacter colonisation should be further investigated and considered when composing phage cocktails.

  19. Toward Understanding Phage:Host Interactions in the Rumen; Complete Genome Sequences of Lytic Phages Infecting Rumen Bacteria

    Directory of Open Access Journals (Sweden)

    Rosalind A. Gilbert

    2017-12-01

    Full Text Available The rumen is known to harbor dense populations of bacteriophages (phages predicted to be capable of infecting a diverse range of rumen bacteria. While bacterial genome sequencing projects are revealing the presence of phages which can integrate their DNA into the genome of their host to form stable, lysogenic associations, little is known of the genetics of phages which utilize lytic replication. These phages infect and replicate within the host, culminating in host lysis, and the release of progeny phage particles. While lytic phages for rumen bacteria have been previously isolated, their genomes have remained largely uncharacterized. Here we report the first complete genome sequences of lytic phage isolates specifically infecting three genera of rumen bacteria: Bacteroides, Ruminococcus, and Streptococcus. All phages were classified within the viral order Caudovirales and include two phage morphotypes, representative of the Siphoviridae and Podoviridae families. The phage genomes displayed modular organization and conserved viral genes were identified which enabled further classification and determination of closest phage relatives. Co-examination of bacterial host genomes led to the identification of several genes responsible for modulating phage:host interactions, including CRISPR/Cas elements and restriction-modification phage defense systems. These findings provide new genetic information and insights into how lytic phages may interact with bacteria of the rumen microbiome.

  20. Suicide Lethality: A Concept Analysis.

    Science.gov (United States)

    DeBastiani, Summer; De Santis, Joseph P

    2018-02-01

    Suicide is a significant health problem internationally. Those who complete suicide may have different behaviors and risk factors than those who attempt a non-fatal suicide. The purpose of this article is to analyze the concept of suicide lethality and propose a clear definition of the concept through the identification of antecedents, attributes, and consequences. A literature search for articles published in the English language between 1970 and 2016 was conducted using MEDLINE, the Cochrane Library, Pubmed, Psychlit, Ovid, PsycINFO, and Proquest. The bibliographies of all included studies were also reviewed to identify additional relevant citations. A concept analysis was conducted on the literature findings using six stages of Walker and Avant's method. The concept analysis differentiated between suicide, lethality, suicidal behavior, and suicide lethality. Presence of a suicide plan or a written suicide note was not found to be associated with the majority of completed suicides included in the definition of suicide lethality. There are a few scales that measure the lethality of a suicide attempt, but none that attempt to measure the concept of suicide lethality as described in this analysis. Clarifying the concept of suicide lethality encourages awareness of the possibility of different suicidal behaviors associated with different suicide outcomes and will inform the development of future nursing interventions. A clearer definition of the concept of suicide lethality will guide clinical practice, research, and policy development aimed at suicide prevention.

  1. Investigation of imaging properties for submillimeter rectangular pinholes

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Dan, E-mail: dxia@uchicago.edu [The Department of Radiology, The University of Chicago, Chicago, Illinois 60637 (United States); Moore, Stephen C., E-mail: scmoore@bwh.harvard.edu, E-mail: miaepark@bwh.harvard.edu, E-mail: mcervo@bwh.harvard.edu; Park, Mi-Ae, E-mail: scmoore@bwh.harvard.edu, E-mail: miaepark@bwh.harvard.edu, E-mail: mcervo@bwh.harvard.edu; Cervo, Morgan, E-mail: scmoore@bwh.harvard.edu, E-mail: miaepark@bwh.harvard.edu, E-mail: mcervo@bwh.harvard.edu [Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts 02115 (United States); Metzler, Scott D., E-mail: metzler@upenn.edu [The Department of Radiology, The University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

    2015-12-15

    Purpose: Recently, a multipinhole collimator with inserts that have both rectangular apertures and rectangular fields of view (FOVs) has been proposed for SPECT imaging since it can tile the projection onto the detector efficiently and the FOVs in transverse and axial directions become separable. The purpose of this study is to investigate the image properties of rectangular-aperture pinholes with submillimeter apertures sizes. Methods: In this work, the authors have conducted sensitivity and FOV experiments for 18 replicates of a prototype insert fabricated in platinum/iridium (Pt/Ir) alloy with submillimeter square-apertures. A sin{sup q}θ fit to the experimental sensitivity has been performed for these inserts. For the FOV measurement, the authors have proposed a new formula to calculate the projection intensity of a flood image on the detector, taking into account the penumbra effect. By fitting this formula to the measured projection data, the authors obtained the acceptance angles. Results: The mean (standard deviation) of fitted sensitivity exponents q and effective edge lengths w{sub e} were, respectively, 10.8 (1.8) and 0.38 mm (0.02 mm), which were close to the values, 7.84 and 0.396 mm, obtained from Monte Carlo calculations using the parameters of the designed inserts. For the FOV measurement, the mean (standard deviation) of the transverse and axial acceptances were 35.0° (1.2°) and 30.5° (1.6°), which are in good agreement with the designed values (34.3° and 29.9°). Conclusions: These results showed that the physical properties of the fabricated inserts with submillimeter aperture size matched our design well.

  2. Characterization of Two Virulent Phages of Lactobacillus plantarum

    Science.gov (United States)

    Briggiler Marcó, Mariángeles; Garneau, Josiane E.; Tremblay, Denise; Quiberoni, Andrea

    2012-01-01

    We characterized two Lactobacillus plantarum virulent siphophages, ATCC 8014-B1 (B1) and ATCC 8014-B2 (B2), previously isolated from corn silage and anaerobic sewage sludge, respectively. Phage B2 infected two of the eight L. plantarum strains tested, while phage B1 infected three. Phage adsorption was highly variable depending on the strain used. Phage defense systems were found in at least two L. plantarum strains, LMG9211 and WCSF1. The linear double-stranded DNA genome of the pac-type phage B1 had 38,002 bp, a G+C content of 47.6%, and 60 open reading frames (ORFs). Surprisingly, the phage B1 genome has 97% identity with that of Pediococcus damnosus phage clP1 and 77% identity with that of L. plantarum phage JL-1; these phages were isolated from sewage and cucumber fermentation, respectively. The double-stranded DNA (dsDNA) genome of the cos-type phage B2 had 80,618 bp, a G+C content of 36.9%, and 127 ORFs with similarities to those of Bacillus and Lactobacillus strains as well as phages. Some phage B2 genes were similar to ORFs from L. plantarum phage LP65 of the Myoviridae family. Additionally, 6 tRNAs were found in the phage B2 genome. Protein analysis revealed 13 (phage B1) and 9 (phage B2) structural proteins. To our knowledge, this is the first report describing such high identity between phage genomes infecting different genera of lactic acid bacteria. PMID:23042172

  3. Diversity and Geographical Distribution of Flavobacterium psychrophilum Isolates and Their Phages: Patterns of Susceptibility to Phage Infection and Phage Host Range

    DEFF Research Database (Denmark)

    Castillo, Daniel; Christiansen, Rói Hammershaimb; Espejo, Romilio

    2014-01-01

    in disease control requires detailed knowledge about the diversity and dynamics of host susceptibility to phage infection. For this reason, we examined the genetic diversity of 49 F. psychrophilum strains isolated in three different areas (Chile, Denmark, and USA) through direct genome restriction enzyme...... analysis (DGREA) and their susceptibility to 33 bacteriophages isolated in Chile and Denmark, thus covering large geographical (>12,000 km) and temporal (>60 years) scales of isolation. An additional 40 phage-resistant isolates obtained from culture experiments after exposure to specific phages were...... examined for changes in phage susceptibility against the 33 phages. The F. psychrophilum and phage populations isolated from Chile and Denmark clustered into geographically distinct groups with respect to DGREA profile and host range, respectively. However, cross infection between Chilean phage isolates...

  4. Morphological evidence for phages in Xylella fastidiosa

    Directory of Open Access Journals (Sweden)

    Civerolo Edwin L

    2008-06-01

    Full Text Available Abstract Presumptive phage particles associated with Xylella fastidiosa strain Temecula-1 grown in PW broth were observed by transmission electron microscopy (TEM in ultrathin sections of bacterial cell-containing low speed centrifugation pellets and in partially purified preparations from CsCl equilibrium centrifugation density gradients. Ultrathin-sectioned cell pellets contained icosahedral particles of about 45 nm in diameter. Samples collected from CsCl density gradients revealed mostly non-tailed icosahedral but also tailed particles. The icosahedral particles could be divided into two types: a large type (about 45 nm and a small type (about 30 nm. Filamentous phage-like particles (17 × 120 to 6,300 nm were also observed. The presence of different types of phage-like particles resembling to those in several bacteriophage families provides new physical evidence, in addition to X. fastidiosa genomic information, that X. fastidiosa possesses active phages. This is the first report of phage particles released in X. fastidiosa cultures.

  5. In Vivo Imaging of Molecularly Targeted Phage

    Directory of Open Access Journals (Sweden)

    Kimberly A. Kelly

    2006-12-01

    Full Text Available Rapid identification of in vivo affinity ligands would have far-reaching applications for imaging specific molecular targets, in vivo systems imaging, and medical use. We have developed a high-throughput method for identifying and optimizing ligands to map and image biologic targets of interest in vivo. We directly labeled viable phage clones with far-red fluorochromes and comparatively imaged them in vivo by multichannel fluorescence ratio imaging. Using Secreted Protein Acidic and Rich in Cysteine (osteonectin and vascular cell adhesion molecule-1 as model targets, we show that: 1 fluorescently labeled phage retains target specificity on labeling; 2 in vivo distribution can be quantitated (detection thresholds of ~ 300 phage/mm3 tissue throughout the entire depth of the tumor using fluorescent tomographic imaging; and 3 fluorescently labeled phage itself can serve as a replenishable molecular imaging agent. The described method should find widespread application in the rapid in vivo discovery and validation of affinity ligands and, importantly, in the use of fluorochrome-labeled phage clones as in vivo imaging agents.

  6. Phages of Listeria offer novel tools for diagnostics and biocontrol

    Directory of Open Access Journals (Sweden)

    Martin J Loessner

    2014-04-01

    Full Text Available Historically, bacteriophages infecting their hosts have perhaps been best known and even notorious for being a nuisance in dairy-fermentation processes. However, with the rapid progress in molecular microbiology and microbial ecology, a new dawn has risen for phages. This review will provide an overview on possible uses and applications of Listeria phages, including phage-typing, reporter phage for bacterial diagnostics, and use of phage as biocontrol agents for food safety. The use of phage-encoded enzymes such as endolysins for the detection and as antimicrobial will also be addressed. Desirable properties of candidate phages for biocontrol will be discussed. While emphasizing the enormous future potential for applications, we will also consider some of the intrinsic limitations dictated by both phage and bacterial ecology.

  7. Current taxonomy of phages infecting lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Jennifer eMahony

    2014-01-01

    Full Text Available Phages infecting lactic acid bacteria have been the focus of significant research attention over the past three decades. Through the isolation and characterization of hundreds of phage isolates, it has been possible to classify phages of the dairy starter and adjunct bacteria Lactococus lactis, Streptococcus thermophilus, Leuconostoc spp. and Lactobacillus spp. Among these, phages of L. lactis have been most thoroughly scrutinized and serve as an excellent model system to address issues that arise when attempting taxonomic classification of phages infecting other LAB species. Here, we present an overview of the current taxonomy of phages infecting LAB genera of industrial significance, the methods employed in these taxonomic efforts and how these may be employed for the taxonomy of phages of currently underrepresented and emerging phage species.

  8. Evaluation of penetration and scattering components in conventional pinhole SPECT: phantom studies using Monte Carlo simulation

    International Nuclear Information System (INIS)

    Deloar, Hossain M; Watabe, Hiroshi; Aoi, Toshiyuki; Iida, Hidehiro

    2003-01-01

    In quantitative pinhole SPECT, photon penetration through the collimator edges (penetration), and photon scattering by the object (object scatter) and collimator (collimator scatter) have not been investigated rigorously. Monte Carlo simulation was used to evaluate these three physical processes for different tungsten knife-edge pinhole collimators using uniform, hotspot and donut phantoms filled with 201 Tl, 99m Tc, 123 I and 131 I solutions. For the hotspot phantom, the penetration levels with respect to total counts for a 1 mm pinhole aperture were 78%, 28% and 23% for 131 I, 123 I and 99m Tc, respectively. For a 2 mm aperture, these values were 65% for 131 I, 16% for 123 I and 12% for 99m Tc. For all pinholes, 201 Tl penetration was less than 4%. The evaluated scatter (from object and collimator) with a hotspot phantom for the 1 mm pinhole was 24%, 16%, 18% and 13% for 201 Tl, 99m Tc, 123 I and 131 I, respectively. Summation of the object and collimator scatter for the uniform phantom was approximately 20% higher than that for the hotspot phantom. Significant counts due to penetration and object and collimator scatter in the reconstructed image were observed inside the core of the donut phantom. The collimator scatter can be neglected for all isotopes used in this study except for 131 I. Object scatter correction for all radionuclides used in this study is necessary and correction for the penetration contribution is necessary for all radionuclides but 201 Tl

  9. Applications of multi-pinhole gamma camera collimation to tomography and image enhancement

    International Nuclear Information System (INIS)

    Simpson, D.R.

    1981-01-01

    Recently, multi-pinhole gamma camera collimation has been introduced in the field of emission tomography. This collimation process simultaneously produces several images covering a limited angular range, which may then be recombined to obtain tomographic slices of the object imaged. This study has investigated a possible method for improving the images obtained by this technique by two multi-pinhole views taken 90 0 apart. During the course of this work, multi-pinhole collimation was also applied to in vivo imaging of the disintegration of tablets. Collimmators were designed and built both for tomography and imaging tablet disintegration, and computer programs were written to reconstruct the images by simple backprojection and by filtered backprojection. The use of multi-pinhole collimators to image the disintegration of tablets in vivo was clearly demonstrated. Phantom tests done in vitro were capable of imaging defects as small as 5 mm 2 , while images made with real tablets both in vitro and in vivo readily showed the onset and progress of the tablet disintegration. Further experiments are planned using this technique to measure gastric emptying times disintegration times of various tablet formulations. Limitations of multi-pinhole technique included problems such as limited ranges of viewing and artifacts introduced due to incomplete sampling

  10. Pinhole diffraction holography for fabrication of high-resolution Fresnel zone plates.

    Science.gov (United States)

    Sarkar, Sankha S; Solak, Harun H; David, Christian; van der Veen, J Friso

    2014-01-27

    Fresnel zone plates (FZPs) play an essential role in high spatial resolution x-ray imaging and analysis of materials in many fields. These diffractive lenses are commonly made by serial writing techniques such as electron beam or focused ion beam lithography. Here we show that pinhole diffraction holography has potential to generate FZP patterns that are free from aberrations and imperfections that may be present in alternative fabrication techniques. In this presented method, FZPs are fabricated by recording interference pattern of a spherical wave generated by diffraction through a pinhole, illuminated with coherent plane wave at extreme ultraviolet (EUV) wavelength. Fundamental and practical issues involved in formation and recording of the interference pattern are considered. It is found that resolution of the produced FZP is directly related to the diameter of the pinhole used and the pinhole size cannot be made arbitrarily small as the transmission of EUV or x-ray light through small pinholes diminishes due to poor refractive index contrast found between materials in these spectral ranges. We also find that the practical restrictions on exposure time due to the light intensity available from current sources directly imposes a limit on the number of zones that can be printed with this method. Therefore a trade-off between the resolution and the FZP diameter exists. Overall, we find that this method can be used to fabricate aberration free FZPs down to a resolution of about 10 nm.

  11. Recovery of phage lambda from ultraviolet damage

    International Nuclear Information System (INIS)

    Devoret, R.; Blanco, M.; George, J.; Radman, M.

    1975-01-01

    Recovery of phage lambda from ultraviolet damage can occur, in the dark, through three types of repair processes as defined by microbiological tests: host-cell reactivation, prophage reactivation, and uv reactivation. This paper reviews the properties of the three repair processes, analyzes their dependence on the functioning of bacterial and phage genes, and discusses their relationship. Progress in the understanding of the molecular mechanisms underlying the three repair processes has been relatively slow, particularly for uv reactivation. It has been shown that host-cell reactivation is due to pyrimidine dimer excision and that prophage reactivation is due to genetic recombination (prereplicative). We provide evidence showing that neither of these mechanisms accounts for uv reactivation of phage lambda. Furthermore, uv reactivation differs from the other repair processes in that it is inducible and error-prone. Whether uv-damaged bacterial DNA is subject to a similar repair process is still an open question

  12. Phage therapy in the food industry.

    Science.gov (United States)

    Endersen, Lorraine; O'Mahony, Jim; Hill, Colin; Ross, R Paul; McAuliffe, Olivia; Coffey, Aidan

    2014-01-01

    Despite advances in modern technologies, the food industry is continuously challenged with the threat of microbial contamination. The overuse of antibiotics has further escalated this problem, resulting in the increasing emergence of antibiotic-resistant foodborne pathogens. Efforts to develop new methods for controlling microbial contamination in food and the food processing environment are extremely important. Accordingly, bacteriophages (phages) and their derivatives have emerged as novel, viable, and safe options for the prevention, treatment, and/or eradication of these contaminants in a range of foods and food processing environments. Whole phages, modified phages, and their derivatives are discussed in terms of current uses and future potential as antimicrobials in the traditional farm-to-fork context, encompassing areas such as primary production, postharvest processing, biosanitation, and biodetection. The review also presents some safety concerns to ensure safe and effective exploitation of bacteriophages in the future.

  13. Genomics of phages with therapeutic potential

    DEFF Research Database (Denmark)

    Zschach, Henrike

    Bacteriophages, viruses that prey on bacteria, have been applied since the 1920’s to treat and prevent bacterial infection. After the discovery of antibiotics, this route was however largely abandoned. Now, with antimicrobial resistance in human-pathogenic bacteria on the rise and a dire need...... for alternatives, phage therapy once again takes center stage. Phage therapy holds the promise of substantial benefits both from the economic as well as the public health perspective but also holds distinct challenges. The aim of this PhD was to address how bioinformatics tools, specifically genomics...... and mathematical modelling, can be applied to move the field towards a future of actual phage therapy in humans. It is composed of three related research projects. The first part of this thesis is an introduction to various topics and methods relevant to the research projects that jointedly make up this Ph...

  14. Phage-Host Interactions in Flavobacterium psychrophilum and the Potential for Phage Therapy in Aquaculture

    DEFF Research Database (Denmark)

    Christiansen, Rói Hammershaimb

    , the increasing problem with antibiotic resistance has led to increased attention to the use of phages for controlling F. psychrophilum infections in aquaculture. In a synopsis and four scientific papers, this PhD project studies the potential and optimizes the use of phage therapy for treatment and prevention......, studies of the genetic diversity and susceptibility patterns of F. psychrophilum strains and phages isolated in three geographically distinct areas (Chile, Denmark, and USA) showed that the strains and phages clustered into geographically distinct groups. However, cross-infectivity between Chilean phage......-phage. In the third paper, a detailed analysis of the resistance mechanisms in F. psychrophilum and six phage resistant mutants was done. The results revealed unique changes in the genomes in all the phage resistant strains and that some of these changes were related to cell surface properties which were suggested...

  15. An improved plating assay for determination of phage titer

    African Journals Online (AJOL)

    RACHEL

    antibiotics to control bacterial infections in swine (Thacker,. 2014). Phage therapy is re-valued by researchers to combat the growing menace of antibiotic-resistant infections (Torres-Barceló and Hochberg, 2016). Determination of phage titer in a sample is a key step in the study of the phage involved. It is very important to.

  16. HostPhinder: A Phage Host Prediction Tool

    Directory of Open Access Journals (Sweden)

    Julia Villarroel

    2016-05-01

    Full Text Available The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within reach. Here, we present HostPhinder, a tool aimed at predicting the bacterial host of phages by examining the phage genome sequence. Using a reference database of 2196 phages with known hosts, HostPhinder predicts the host species of a query phage as the host of the most genomically similar reference phages. As a measure of genomic similarity the number of co-occurring k-mers (DNA sequences of length k is used. Using an independent evaluation set, HostPhinder was able to correctly predict host genus and species for 81% and 74% of the phages respectively, giving predictions for more phages than BLAST and significantly outperforming BLAST on phages for which both had predictions. HostPhinder predictions on phage draft genomes from the INTESTI phage cocktail corresponded well with the advertised targets of the cocktail. Our study indicates that for most phages genomic similarity correlates well with related bacterial hosts. HostPhinder is available as an interactive web service [1] and as a stand alone download from the Docker registry [2].

  17. Phage therapy reduces Campylobacter jejuni colonization in broilers

    NARCIS (Netherlands)

    Wagenaar, J.A.; Bergen, van M.A.P.; Mueller, M.A.; Wassenaar, T.M.; Carlton, R.M.

    2005-01-01

    The effect of phage therapy in the control of Campylobacter jejuni colonization in young broilers, either as a preventive or a therapeutic measure, was tested. A prevention group was infected with C. jejuni at day 4 of a 10-day phage treatment. A therapeutic group was phage treated for 6 days,

  18. The Caulobacter crescentus phage phiCbK: genomics of a canonical phage

    Directory of Open Access Journals (Sweden)

    Gill Jason J

    2012-10-01

    Full Text Available Abstract Background The bacterium Caulobacter crescentus is a popular model for the study of cell cycle regulation and senescence. The large prolate siphophage phiCbK has been an important tool in C. crescentus biology, and has been studied in its own right as a model for viral morphogenesis. Although a system of some interest, to date little genomic information is available on phiCbK or its relatives. Results Five novel phiCbK-like C. crescentus bacteriophages, CcrMagneto, CcrSwift, CcrKarma, CcrRogue and CcrColossus, were isolated from the environment. The genomes of phage phiCbK and these five environmental phage isolates were obtained by 454 pyrosequencing. The phiCbK-like phage genomes range in size from 205 kb encoding 318 proteins (phiCbK to 280 kb encoding 448 proteins (CcrColossus, and were found to contain nonpermuted terminal redundancies of 10 to 17 kb. A novel method of terminal ligation was developed to map genomic termini, which confirmed termini predicted by coverage analysis. This suggests that sequence coverage discontinuities may be useable as predictors of genomic termini in phage genomes. Genomic modules encoding virion morphogenesis, lysis and DNA replication proteins were identified. The phiCbK-like phages were also found to encode a number of intriguing proteins; all contain a clearly T7-like DNA polymerase, and five of the six encode a possible homolog of the C. crescentus cell cycle regulator GcrA, which may allow the phage to alter the host cell’s replicative state. The structural proteome of phage phiCbK was determined, identifying the portal, major and minor capsid proteins, the tail tape measure and possible tail fiber proteins. All six phage genomes are clearly related; phiCbK, CcrMagneto, CcrSwift, CcrKarma and CcrRogue form a group related at the DNA level, while CcrColossus is more diverged but retains significant similarity at the protein level. Conclusions Due to their lack of any apparent relationship to

  19. Measuring Beam Sizes and Ultra-Small Electron Emittances Using an X-ray Pinhole Camera.

    Science.gov (United States)

    Elleaume, P; Fortgang, C; Penel, C; Tarazona, E

    1995-09-01

    A very simple pinhole camera set-up has been built to diagnose the electron beam emittance of the ESRF. The pinhole is placed in the air next to an Al window. An image is obtained with a CCD camera imaging a fluorescent screen. The emittance is deduced from the size of the image. The relationship between the measured beam size and the electron beam emittance depends upon the lattice functions alpha, beta and eta, the screen resolution, pinhole size and photon beam divergence. The set-up is capable of measuring emittances as low as 5 pm rad and is presently routinely used as both an electron beam imaging device and an emittance diagnostic.

  20. Collimated proton acceleration in light sail regime with a tailored pinhole target

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H. Y.; Zepf, M. [Helmholtz Institute Jena, Fröbelstieg 3, 07743 Jena (Germany); Yan, X. Q. [State Key Laboratory of Nuclear Physics and Technology and Key Lab of High Energy Density Physics Simulation, CAPT, Peking University, Beijing 100871 (China)

    2014-06-15

    A scheme for producing collimated protons from laser interactions with a diamond-like-carbon + pinhole target is proposed. The process is based on radiation pressure acceleration in the multi-species light-sail regime [B. Qiao et al., Phys. Rev. Lett. 105, 155002 (2010); T. P. Yu et al., Phys. Rev. Lett. 105, 065002 (2010)]. Particle-in-cell simulations demonstrate that transverse quasistatic electric field at TV/m level can be generated in the pinhole. The transverse electric field suppresses the transverse expansion of protons effectively, resulting in a higher density and more collimated proton beam compared with a single foil target. The dependence of the proton beam divergence on the parameters of the pinhole is also investigated.

  1. Collimated proton acceleration in light sail regime with a tailored pinhole target

    International Nuclear Information System (INIS)

    Wang, H. Y.; Zepf, M.; Yan, X. Q.

    2014-01-01

    A scheme for producing collimated protons from laser interactions with a diamond-like-carbon + pinhole target is proposed. The process is based on radiation pressure acceleration in the multi-species light-sail regime [B. Qiao et al., Phys. Rev. Lett. 105, 155002 (2010); T. P. Yu et al., Phys. Rev. Lett. 105, 065002 (2010)]. Particle-in-cell simulations demonstrate that transverse quasistatic electric field at TV/m level can be generated in the pinhole. The transverse electric field suppresses the transverse expansion of protons effectively, resulting in a higher density and more collimated proton beam compared with a single foil target. The dependence of the proton beam divergence on the parameters of the pinhole is also investigated

  2. An analytical simulation technique for cone-beam CT and pinhole SPECT

    International Nuclear Information System (INIS)

    Zhang Xuezhu; Qi Yujin

    2011-01-01

    This study was aimed at developing an efficient simulation technique with an ordinary PC. The work involved derivation of mathematical operators, analytic phantom generations, and effective analytical projectors developing for cone-beam CT and pinhole SPECT imaging. The computer simulations based on the analytical projectors were developed by ray-tracing method for cone-beam CT and voxel-driven method for pinhole SPECT of degrading blurring. The 3D Shepp-Logan, Jaszczak and Defrise phantoms were used for simulation evaluations and image reconstructions. The reconstructed phantom images were of good accuracy with the phantoms. The results showed that the analytical simulation technique is an efficient tool for studying cone-beam CT and pinhole SPECT imaging. (authors)

  3. Optimising performance of a confocal fluorescence microscope with a differential pinhole

    International Nuclear Information System (INIS)

    Kakade, Rohan; Walker, John G; Phillips, Andrew J

    2016-01-01

    The signal-to-noise ratio (SNR)-resolution trade-off is of great importance to bio-imaging applications where the aim is to image the sample using as little light as possible without significantly sacrificing image quality. In this paper the inherent SNR-resolution tradeoff in Confocal Fluorescence Microscopy (CFM) systems is presented by means of an effective tradeoff curve. A CFM system that employs a differential pinhole detection scheme has recently been shown to offer increased resolution, but at the expense of SNR. An optimum profile for the differential pinhole is identified in this paper that offers improved performance over a conventional (circular pinhole) system. The performance enhancement is illustrated through computer simulation. (paper)

  4. Applications of multi-pinhole gamma camera collimation to tomography and image enhancement

    Science.gov (United States)

    Simpson, D. R.

    1981-06-01

    Multi-pinhole gamma camera collimation was introduced in the field of emission tomography. This collimation process simultaneously produces several images covering a limited angular range, which may then be recombined to obtain tomographic slices of the object imaged. A possible method for improving the images obtained by this technique by combining two multi-pinhole views taken 90 deg apart was investigated. Collimators were designed and built both for tomography and imaging tablet disintegration, and computer programs were written to reconstruct the images by simple backprojection and by filtered backprojection. The use of multi-pinhole collimators to image the disintegration of tablets in vivo was clearly demonstrated. Phantom tests done in vitro were capable of imaging defects as small as 5 sq mm, while images made with real tablets both in vitro and in vivo readily showed the onset and progress of the tablet disintegration.

  5. High-resolution tomography of positron emitters with clustered pinhole SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Goorden, Marlies C; Beekman, Freek J [Section of Radiation Detection and Medical Imaging, Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)], E-mail: m.c.goorden@tudelft.nl

    2010-03-07

    State-of-the-art small-animal single photon emission computed tomography (SPECT) enables sub-half-mm resolution imaging of radio-labelled molecules. Due to severe photon penetration through pinhole edges, current multi-pinhole SPECT is not suitable for high-resolution imaging of photons with high energies, such as the annihilation photons emitted by positron emitting tracers (511 keV). To deal with this edge penetration, we introduce here clustered multi-pinhole SPECT (CMP): each pinhole in a cluster has a narrow opening angle to reduce photon penetration. Using simulations, CMP is compared with (i) a collimator with traditional pinholes that is currently used for sub-half-mm imaging of SPECT isotopes (U-SPECT-II), and (ii), like (i) but with collimator thickness adapted to image high-energy photons (traditional multi-pinhole SPECT, TMP). At 511 keV, U-SPECT-II is able to resolve the 0.9 mm rods of an iteratively reconstructed Jaszczak-like capillary hot rod phantom, and while TMP only leads to small improvements, CMP can resolve rods as small as 0.7 mm. Using a digital tumour phantom, we show that CMP resolves many details not assessable with standard USPECT-II and TMP collimators. Furthermore, CMP makes it possible to visualize uptake of positron emitting tracers in sub-compartments of a digital mouse striatal brain phantom. This may open up unique possibilities for analysing processes such as those underlying the function of neurotransmitter systems. Additional potential of CMP may include (i) the imaging of other high-energy single-photon emitters (e.g. I-131) and (ii) localized imaging of positron emitting tracers simultaneously with single photon emitters, with an even better resolution than coincidence PET.

  6. Absolute quantitative total-body small-animal SPECT with focusing pinholes

    International Nuclear Information System (INIS)

    Wu, Chao; Have, Frans van der; Vastenhouw, Brendan; Beekman, Freek J.; Dierckx, Rudi A.J.O.; Paans, Anne M.J.

    2010-01-01

    In pinhole SPECT, attenuation of the photon flux on trajectories between source and pinholes affects quantitative accuracy of reconstructed images. Previously we introduced iterative methods that compensate for image degrading effects of detector and pinhole blurring, pinhole sensitivity and scatter for multi-pinhole SPECT. The aim of this paper is (1) to investigate the accuracy of the Chang algorithm in rodents and (2) to present a practical Chang-based method using body outline contours obtained with optical cameras. Here we develop and experimentally validate a practical method for attenuation correction based on a Chang first-order method. This approach has the advantage that it is employed after, and therefore independently from, iterative reconstruction. Therefore, no new system matrix has to be calculated for each specific animal. Experiments with phantoms and animals were performed with a high-resolution focusing multi-pinhole SPECT system (U-SPECT-II, MILabs, The Netherlands). This SPECT system provides three additional optical camera images of the animal for each SPECT scan from which the animal contour can be estimated. Phantom experiments demonstrated that an average quantification error of -18.7% was reduced to -1.7% when both window-based scatter correction and Chang correction based on the body outline from optical images were applied. Without scatter and attenuation correction, quantification errors in a sacrificed rat containing sources with known activity ranged from -23.6 to -9.3%. These errors were reduced to values between -6.3 and +4.3% (with an average magnitude of 2.1%) after applying scatter and Chang attenuation correction. We conclude that the modified Chang correction based on body contour combined with window-based scatter correction is a practical method for obtaining small-animal SPECT images with high quantitative accuracy. (orig.)

  7. Maximum likelihood reconstruction for pinhole SPECT with a displaced center-of-rotation

    International Nuclear Information System (INIS)

    Li, J.; Jaszczak, R.J.; Coleman, R.E.

    1995-01-01

    In this paper, the authors describe the implementation of a maximum likelihood (ML), algorithm using expectation maximization (EM) for pin-hole SPECT with a displaced center-of-rotation. A ray-tracing technique is used in implementing the ML-EM algorithm. The proposed ML-EM algorithm is able to correct the center of rotation displacement which can be characterized by two orthogonal components. The algorithm is tested using experimentally acquired data, and the results demonstrate that the pinhole ML-EM algorithm is able to correct artifacts associated with the center-of-rotation displacement

  8. How to Name and Classify Your Phage: An Informal Guide

    Directory of Open Access Journals (Sweden)

    Evelien Adriaenssens

    2017-04-01

    Full Text Available With this informal guide, we try to assist both new and experienced phage researchers through two important stages that follow phage discovery; that is, naming and classification. Providing an appropriate name for a bacteriophage is not as trivial as it sounds, and the effects might be long-lasting in databases and in official taxon names. Phage classification is the responsibility of the Bacterial and Archaeal Viruses Subcommittee (BAVS of the International Committee on the Taxonomy of Viruses (ICTV. While the BAVS aims at providing a holistic approach to phage taxonomy, for individual researchers who have isolated and sequenced a new phage, this can be a little overwhelming. We are now providing these researchers with an informal guide to phage naming and classification, taking a “bottom-up” approach from the phage isolate level.

  9. Twelve previously unknown phage genera are ubiquitous in global oceans.

    Science.gov (United States)

    Holmfeldt, Karin; Solonenko, Natalie; Shah, Manesh; Corrier, Kristen; Riemann, Lasse; Verberkmoes, Nathan C; Sullivan, Matthew B

    2013-07-30

    Viruses are fundamental to ecosystems ranging from oceans to humans, yet our ability to study them is bottlenecked by the lack of ecologically relevant isolates, resulting in "unknowns" dominating culture-independent surveys. Here we present genomes from 31 phages infecting multiple strains of the aquatic bacterium Cellulophaga baltica (Bacteroidetes) to provide data for an underrepresented and environmentally abundant bacterial lineage. Comparative genomics delineated 12 phage groups that (i) each represent a new genus, and (ii) represent one novel and four well-known viral families. This diversity contrasts the few well-studied marine phage systems, but parallels the diversity of phages infecting human-associated bacteria. Although all 12 Cellulophaga phages represent new genera, the podoviruses and icosahedral, nontailed ssDNA phages were exceptional, with genomes up to twice as large as those previously observed for each phage type. Structural novelty was also substantial, requiring experimental phage proteomics to identify 83% of the structural proteins. The presence of uncommon nucleotide metabolism genes in four genera likely underscores the importance of scavenging nutrient-rich molecules as previously seen for phages in marine environments. Metagenomic recruitment analyses suggest that these particular Cellulophaga phages are rare and may represent a first glimpse into the phage side of the rare biosphere. However, these analyses also revealed that these phage genera are widespread, occurring in 94% of 137 investigated metagenomes. Together, this diverse and novel collection of phages identifies a small but ubiquitous fraction of unknown marine viral diversity and provides numerous environmentally relevant phage-host systems for experimental hypothesis testing.

  10. Theories of Lethal Mutagenesis: From Error Catastrophe to Lethal Defection.

    Science.gov (United States)

    Tejero, Héctor; Montero, Francisco; Nuño, Juan Carlos

    2016-01-01

    RNA viruses get extinct in a process called lethal mutagenesis when subjected to an increase in their mutation rate, for instance, by the action of mutagenic drugs. Several approaches have been proposed to understand this phenomenon. The extinction of RNA viruses by increased mutational pressure was inspired by the concept of the error threshold. The now classic quasispecies model predicts the existence of a limit to the mutation rate beyond which the genetic information of the wild type could not be efficiently transmitted to the next generation. This limit was called the error threshold, and for mutation rates larger than this threshold, the quasispecies was said to enter into error catastrophe. This transition has been assumed to foster the extinction of the whole population. Alternative explanations of lethal mutagenesis have been proposed recently. In the first place, a distinction is made between the error threshold and the extinction threshold, the mutation rate beyond which a population gets extinct. Extinction is explained from the effect the mutation rate has, throughout the mutational load, on the reproductive ability of the whole population. Secondly, lethal defection takes also into account the effect of interactions within mutant spectra, which have been shown to be determinant for the understanding the extinction of RNA virus due to an augmented mutational pressure. Nonetheless, some relevant issues concerning lethal mutagenesis are not completely understood yet, as so survival of the flattest, i.e. the development of resistance to lethal mutagenesis by evolving towards mutationally more robust regions of sequence space, or sublethal mutagenesis, i.e., the increase of the mutation rate below the extinction threshold which may boost the adaptability of RNA virus, increasing their ability to develop resistance to drugs (including mutagens). A better design of antiviral therapies will still require an improvement of our knowledge about lethal

  11. Multi-pinhole collimator design for small-object imaging with SiliSPECT: a high-resolution SPECT

    International Nuclear Information System (INIS)

    Shokouhi, S; Peterson, T E; Metzler, S D; Wilson, D W

    2009-01-01

    We have designed a multi-pinhole collimator for a dual-headed, stationary SPECT system that incorporates high-resolution silicon double-sided strip detectors. The compact camera design of our system enables imaging at source-collimator distances between 20 and 30 mm. Our analytical calculations show that using knife-edge pinholes with small-opening angles or cylindrically shaped pinholes in a focused, multi-pinhole configuration in combination with this camera geometry can generate narrow sensitivity profiles across the field of view that can be useful for imaging small objects at high sensitivity and resolution. The current prototype system uses two collimators each containing 127 cylindrically shaped pinholes that are focused toward a target volume. Our goal is imaging objects such as a mouse brain, which could find potential applications in molecular imaging.

  12. Formulation, stabilisation and encapsulation of bacteriophage for phage therapy.

    Science.gov (United States)

    Malik, Danish J; Sokolov, Ilya J; Vinner, Gurinder K; Mancuso, Francesco; Cinquerrui, Salvatore; Vladisavljevic, Goran T; Clokie, Martha R J; Garton, Natalie J; Stapley, Andrew G F; Kirpichnikova, Anna

    2017-11-01

    Against a backdrop of global antibiotic resistance and increasing awareness of the importance of the human microbiota, there has been resurgent interest in the potential use of bacteriophages for therapeutic purposes, known as phage therapy. A number of phage therapy phase I and II clinical trials have concluded, and shown phages don't present significant adverse safety concerns. These clinical trials used simple phage suspensions without any formulation and phage stability was of secondary concern. Phages have a limited stability in solution, and undergo a significant drop in phage titre during processing and storage which is unacceptable if phages are to become regulated pharmaceuticals, where stable dosage and well defined pharmacokinetics and pharmacodynamics are de rigueur. Animal studies have shown that the efficacy of phage therapy outcomes depend on the phage concentration (i.e. the dose) delivered at the site of infection, and their ability to target and kill bacteria, arresting bacterial growth and clearing the infection. In addition, in vitro and animal studies have shown the importance of using phage cocktails rather than single phage preparations to achieve better therapy outcomes. The in vivo reduction of phage concentration due to interactions with host antibodies or other clearance mechanisms may necessitate repeated dosing of phages, or sustained release approaches. Modelling of phage-bacterium population dynamics reinforces these points. Surprisingly little attention has been devoted to the effect of formulation on phage therapy outcomes, given the need for phage cocktails, where each phage within a cocktail may require significantly different formulation to retain a high enough infective dose. This review firstly looks at the clinical needs and challenges (informed through a review of key animal studies evaluating phage therapy) associated with treatment of acute and chronic infections and the drivers for phage encapsulation. An important driver

  13. Pinhole single-photon emission tomography reconstruction based on median root prior

    International Nuclear Information System (INIS)

    Sohlberg, Antti; Kuikka, Jyrki T.; Ruotsalainen, Ulla

    2003-01-01

    The maximum likelihood expectation maximisation (ML-EM) algorithm can be used to reduce reconstruction artefacts produced by filtered backprojection (FBP) methods in pinhole single-photon emission tomography (SPET). However, ML-EM suffers from noise propagation along iterations, which leads to quantitatively unpleasant reconstruction results. To avoid this increase in noise, the median root prior (MRP) algorithm for pinhole SPET was implemented. Projection data of a line source and Picker's thyroid phantom were collected using a single-head gamma camera with a pinhole collimator. MRP was added to existing pinhole ML-EM reconstruction algorithm and the phantom studies were reconstructed using MRP, ML-EM and FBP for comparison. Coefficients of variation, contrasts and full-widths at half-maximum were calculated and showed a clear reduction in noise without significant loss of resolution or decrease in contrast when MRP was applied. MRP also produced visually pleasing images even with high iteration numbers, free of the checkerboard-type noise patterns which are typical of ML-EM images. (orig.)

  14. Multi-pinhole SPECT calibration. Influence of data noise and systematic orbit deviations

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Lin; Vunckx, Kathleen; Nuyts, Johan [Katholieke Univ. Leuven (Belgium). Dept. of Nuclear Medicine

    2011-07-01

    Previously it has been proved that the geometry of a multi-pinhole SPECT system with circular orbit can be uniquely determined from a measurement of two point sources, without the knowledge of the distance between them. In this paper, we report that this conclusion only holds if the motion of the camera is perfectly circular. In reality, the detector heads systematically slightly deviate from the circular orbit, which may introduce nonnegligible bias in the calibrated parameters. An analytical linear model was extended to estimate the influence of both data noise and systematic deviations on the accuracy of the calibration and the image quality of the reconstruction. It turns out that applying the knowledge of the distances greatly reduces the reconstruction error, especially in the presence of systematic deviations. In addition, we propose that instead of using the information about the distances between the point sources, it is more straightforward to use the knowledge about the distances between the pinhole apertures during multi-pinhole calibration. The two distance fixing approaches yield similar calibration accuracy, but fixing the inter-pinhole distances is more preferable since it facilitates simultaneous animal-calibration data acquisition. Our theoretical results are supported by reconstruction images of a Jaszczak-type phantom. (orig.)

  15. PINEX-2: pinhole-TV imaging of fuel ejection from an internally vented capsule

    International Nuclear Information System (INIS)

    Berzins, G.J.; Lumpkin, A.H.

    1979-01-01

    The LASL pinhole-intensified TV system was used at the TREAT reactor to image an internally vented, fuel-ejection capsule designed and built by HEDL. Several improvements in the imaging system over PINEX-1 were incorporated. A sequence of 16-ms TV frames shows axial expansion, expulsion of fuel from the pin, and retention of clad integrity during the time of coverage

  16. Stability Measurements for Alignment of the NIF Neutron Imaging System Pinhole Array

    International Nuclear Information System (INIS)

    Fittinghoff, D.N.; Bower, D.E.; Drury, O.B.; Dzenitis, J.M.; Frank, M.; Buckles, R.A.; Munson, C.; Wilde, C.H.

    2011-01-01

    The alignment system for the National Ignition Facility's neutron imaging system has been commissioned and measurements of the relative stability of the 90-315 DIM, the front and the back of the neutron imaging pinhole array and an exploding pusher target have been made using the 90-135 and the 90-258 opposite port alignment systems. Additionally, a laser beam shot from the neutron-imaging Annex and reflected from a mirror at the back of the pinhole array was used to monitor the pointing of the pinhole. Over a twelve hour period, the relative stability of these parts was found to be within ∼ ±18 (micro)m rms even when using manual methods for tracking the position of the objects. For highly visible features, use of basic particle tracking techniques found that the front of the pinhole array was stable relative to the 90-135 opposite port alignment camera to within ±3.4 (micro)m rms. Reregistration, however, of the opposite port alignment systems themselves using the target alignment sensor was found to change the expected position of target chamber center by up to 194 (micro)m.

  17. Reflections on Using Pinhole Photography as a Pedagogical and Methodological Tool with Adolescents in Wild Nature

    Science.gov (United States)

    Socha, Teresa; Potter, Tom; Potter, Stephanie; Jickling, Bob

    2016-01-01

    This paper shares our experiences using pinhole photography with adolescents as both a pedagogical tool to support and deepen adolescent experiences in wild nature, and as a visual methodological tool to elucidate their experiences. Reflecting on a journey that explored the nature-based experiences of two adolescents on a family canoe trip in…

  18. Assembling filamentous phage occlude pIV channels.

    Science.gov (United States)

    Marciano, D K; Russel, M; Simon, S M

    2001-07-31

    Filamentous phage f1 is exported from its Escherichia coli host without killing the bacterial cell. Phage-encoded protein pIV, which is required for phage assembly and secretion, forms large highly conductive channels in the outer membrane of E. coli. It has been proposed that the phage are extruded across the bacterial outer membrane through pIV channels. To test this prediction, we developed an in vivo assay by using a mutant pIV that functions in phage export but whose channel opens in the absence of phage extrusion. In E. coli lacking its native maltooligosacharride transporter LamB, this pIV variant allowed oligosaccharide transport across the outer membrane. This entry of oligosaccharide was decreased by phage production and still further decreased by production of phage that cannot be released from the cell surface. Thus, exiting phage block the pIV-dependent entry of oligosaccharide, suggesting that phage occupy the lumen of pIV channels. This study provides the first evidence, to our knowledge, for viral exit through a large aqueous channel.

  19. Non-Lethal Weapons Program

    Science.gov (United States)

    Sheets Frequently Asked Questions Non-Lethal Weapons FAQs Active Denial System FAQs Human Electro -Muscular Incapacitation FAQs Related Links Business Opportunities Contact JNLWD Congressional Engagement , Wednesday, Sept 20, 2017. The Active Denial System, blunt-impact munitions, dazzling lasers, LRAD 100X

  20. A century of the phage: past, present and future.

    Science.gov (United States)

    Salmond, George P C; Fineran, Peter C

    2015-12-01

    Viruses that infect bacteria (bacteriophages; also known as phages) were discovered 100 years ago. Since then, phage research has transformed fundamental and translational biosciences. For example, phages were crucial in establishing the central dogma of molecular biology - information is sequentially passed from DNA to RNA to proteins - and they have been shown to have major roles in ecosystems, and help drive bacterial evolution and virulence. Furthermore, phage research has provided many techniques and reagents that underpin modern biology - from sequencing and genome engineering to the recent discovery and exploitation of CRISPR-Cas phage resistance systems. In this Timeline, we discuss a century of phage research and its impact on basic and applied biology.

  1. Pseudomonas predators: understanding and exploiting phage-host interactions.

    Science.gov (United States)

    De Smet, Jeroen; Hendrix, Hanne; Blasdel, Bob G; Danis-Wlodarczyk, Katarzyna; Lavigne, Rob

    2017-09-01

    Species in the genus Pseudomonas thrive in a diverse set of ecological niches and include crucial pathogens, such as the human pathogen Pseudomonas aeruginosa and the plant pathogen Pseudomonas syringae. The bacteriophages that infect Pseudomonas spp. mirror the widespread and diverse nature of their hosts. Therefore, Pseudomonas spp. and their phages are an ideal system to study the molecular mechanisms that govern virus-host interactions. Furthermore, phages are principal catalysts of host evolution and diversity, which directly affects the ecological roles of environmental and pathogenic Pseudomonas spp. Understanding these interactions not only provides novel insights into phage biology but also advances the development of phage therapy, phage-derived antimicrobial strategies and innovative biotechnological tools that may be derived from phage-bacteria interactions.

  2. Molecular Characterization of Three Lactobacillus delbrueckii subsp. bulgaricus Phages

    Science.gov (United States)

    Casey, Eoghan; Mahony, Jennifer; O'Connell-Motherway, Mary; Bottacini, Francesca; Cornelissen, Anneleen; Neve, Horst; Heller, Knut J.; Noben, Jean-Paul; Dal Bello, Fabio

    2014-01-01

    In this study, three phages infecting Lactobacillus delbrueckii subsp. bulgaricus, named Ld3, Ld17, and Ld25A, were isolated from whey samples obtained from various industrial fermentations. These phages were further characterized in a multifaceted approach: (i) biological and physical characterization through host range analysis and electron microscopy; (ii) genetic assessment through genome analysis; (iii) mass spectrometry analysis of the structural components of the phages; and (iv), for one phage, transcriptional analysis by Northern hybridization, reverse transcription-PCR, and primer extension. The three obtained phage genomes display high levels of sequence identity to each other and to genomes of the so-called group b L. delbrueckii phages c5, LL-Ku, and phiLdb, where some of the observed differences are believed to be responsible for host range variations. PMID:25002431

  3. Molecular characterization of three Lactobacillus delbrueckii subsp. bulgaricus phages.

    Science.gov (United States)

    Casey, Eoghan; Mahony, Jennifer; O'Connell-Motherway, Mary; Bottacini, Francesca; Cornelissen, Anneleen; Neve, Horst; Heller, Knut J; Noben, Jean-Paul; Dal Bello, Fabio; van Sinderen, Douwe

    2014-09-01

    In this study, three phages infecting Lactobacillus delbrueckii subsp. bulgaricus, named Ld3, Ld17, and Ld25A, were isolated from whey samples obtained from various industrial fermentations. These phages were further characterized in a multifaceted approach: (i) biological and physical characterization through host range analysis and electron microscopy; (ii) genetic assessment through genome analysis; (iii) mass spectrometry analysis of the structural components of the phages; and (iv), for one phage, transcriptional analysis by Northern hybridization, reverse transcription-PCR, and primer extension. The three obtained phage genomes display high levels of sequence identity to each other and to genomes of the so-called group b L. delbrueckii phages c5, LL-Ku, and phiLdb, where some of the observed differences are believed to be responsible for host range variations. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  4. Complete Genome Sequence of Pseudomonas aeruginosa Phage AAT-1.

    Science.gov (United States)

    Andrade-Domínguez, Andrés; Kolter, Roberto

    2016-08-25

    Aspects of the interaction between phages and animals are of interest and importance for medical applications. Here, we report the genome sequence of the lytic Pseudomonas phage AAT-1, isolated from mammalian serum. AAT-1 is a double-stranded DNA phage, with a genome of 57,599 bp, containing 76 predicted open reading frames. Copyright © 2016 Andrade-Domínguez and Kolter.

  5. Molecular Characterization of Three Lactobacillus delbrueckii subsp. bulgaricus Phages

    OpenAIRE

    Casey, Eoghan; Mahony, Jennifer; O'Connell-Motherway, Mary; Bottacini, Francesca; Cornelissen, Anneleen; Neve, Horst; Heller, Knut J.; Noben, Jean-Paul; Dal Bello, Fabio; van Sinderen, Douwe

    2014-01-01

    In this study, three phages infecting Lactobacillus delbrueckii subsp. bulgaricus, named Ld3, Ld17, and Ld25A, were isolated from whey samples obtained from various industrial fermentations. These phages were further characterized in a multifaceted approach: (i) biological and physical characterization through host range analysis and electron microscopy; (ii) genetic assessment through genome analysis; (iii) mass spectrometry analysis of the structural components of the phages; and (iv), for ...

  6. Isolation and Characterization of Phages Infecting Bacillus subtilis

    Directory of Open Access Journals (Sweden)

    Anna Krasowska

    2015-01-01

    Full Text Available Bacteriophages have been suggested as an alternative approach to reduce the amount of pathogens in various applications. Bacteriophages of various specificity and virulence were isolated as a means of controlling food-borne pathogens. We studied the interaction of bacteriophages with Bacillus species, which are very often persistent in industrial applications such as food production due to their antibiotic resistance and spore formation. A comparative study using electron microscopy, PFGE, and SDS-PAGE as well as determination of host range, pH and temperature resistance, adsorption rate, latent time, and phage burst size was performed on three phages of the Myoviridae family and one phage of the Siphoviridae family which infected Bacillus subtilis strains. The phages are morphologically different and characterized by icosahedral heads and contractile (SIOΦ, SUBω, and SPOσ phages or noncontractile (ARπ phage tails. The genomes of SIOΦ and SUBω are composed of 154 kb. The capsid of SIOΦ is composed of four proteins. Bacteriophages SPOσ and ARπ have genome sizes of 25 kbp and 40 kbp, respectively. Both phages as well as SUBω phage have 14 proteins in their capsids. Phages SIOΦ and SPOσ are resistant to high temperatures and to the acid (4.0 and alkaline (9.0 and 10.0 pH.

  7. The genomes and comparative genomics of Lactobacillus delbrueckii phages.

    Science.gov (United States)

    Riipinen, Katja-Anneli; Forsman, Päivi; Alatossava, Tapani

    2011-07-01

    Lactobacillus delbrueckii phages are a great source of genetic diversity. Here, the genome sequences of Lb. delbrueckii phages LL-Ku, c5 and JCL1032 were analyzed in detail, and the genetic diversity of Lb. delbrueckii phages belonging to different taxonomic groups was explored. The lytic isometric group b phages LL-Ku (31,080 bp) and c5 (31,841 bp) showed a minimum nucleotide sequence identity of 90% over about three-fourths of their genomes. The genomic locations of their lysis modules were unique, and the genomes featured several putative overlapping transcription units of genes. LL-Ku and c5 virions displayed peptidoglycan hydrolytic activity associated with a ~36-kDa protein similar in size to the endolysin. Unexpectedly, the 49,433-bp genome of the prolate phage JCL1032 (temperate, group c) revealed a conserved gene order within its structural genes. Lb. delbrueckii phages representing groups a (a phage LL-H), b and c possessed only limited protein sequence homology. Genomic comparison of LL-Ku and c5 suggested that diversification of Lb. delbrueckii phages is mainly due to insertions, deletions and recombination. For the first time, the complete genome sequences of group b and c Lb. delbrueckii phages are reported.

  8. Evolution of phage display technology: from discovery to application.

    Science.gov (United States)

    Rahbarnia, Leila; Farajnia, Safar; Babaei, Hossein; Majidi, Jafar; Veisi, Kamal; Ahmadzadeh, Vahideh; Akbari, Bahman

    2017-03-01

    Phage display technology as a selection-based system is an attractive method for evolution of new biological drugs. Unique ability of phage libraries for displaying proteins on bacteriophage surfaces enable them to make a major contribution in diverse fields of researches related to the diagnosis and therapy of diseases. One of the great challenges facing researchers is the modification of phage display technology and the development of new applications. This article reviews the molecular basis of phage display library, and summarizes the novel and specific applications of this technique in the field of biological drugs development including therapeutic antibodies, peptides, vaccines, and catalytic antibodies.

  9. Ligand-directed profiling of organelles with internalizing phage libraries

    Science.gov (United States)

    Dobroff, Andrey S.; Rangel, Roberto; Guzman-Roja, Liliana; Salmeron, Carolina C.; Gelovani, Juri G.; Sidman, Richard L.; Bologa, Cristian G.; Oprea, Tudor I.; Brinker, C. Jeffrey; Pasqualini, Renata; Arap, Wadih

    2015-01-01

    Phage display is a resourceful tool to, in an unbiased manner, discover and characterize functional protein-protein interactions, to create vaccines, and to engineer peptides, antibodies, and other proteins as targeted diagnostic and/or therapeutic agents. Recently, our group has developed a new class of internalizing phage (iPhage) for ligand-directed targeting of organelles and/or to identify molecular pathways within live cells. This unique technology is suitable for applications ranging from fundamental cell biology to drug development. Here we describe the method for generating and screening the iPhage display system, and explain how to select and validate candidate internalizing homing peptide. PMID:25640897

  10. Oxygen-dependent radiosensitivity of Escherichia coli and mitigation in lethality by superoxide dismutase

    International Nuclear Information System (INIS)

    Niwa, Taeko; Yamaguchi, Hikoyuki; Yano, Keiji

    1978-01-01

    Oxygen-dependent radiosensitivity of Escherichia coli W3623 his - was confirmed. Regarding cellular superoxide dismutase (SOD), cells grown oxically gained higher activity than those anoxically, however, the reinforced enzyme level could not compensate the oxygen effect, i.e., the enhanced lethal effect of oxic γ-irradiation. Rather, the enhancement of oxygen effect was found in cells grown oxically compared with those anoxically. Oxygen enhanced lethality was mitigated to the extent by the amount of added SOD into the cell suspension to be irradiated. The results supported a proposal that superoxide anion, O 2 - , is involved in the oxygen effect, with the most likely site of the damage in the outer structure of cell but not in the cell matrix. Reverse oxygen effect could be found with lambda phage DNA in transfecting ability. Added SOD protected phage DNA somewhat in oxic irradiation. While considerable protections were found in anoxic one with the added SOD even autoclaved but their function was still unknown. (auth.)

  11. Lethal mechanisms in gastric volvulus.

    Science.gov (United States)

    Omond, Kimberley J; Byard, Roger W

    2017-01-01

    A 55-year-old wheelchair-bound woman with severe cerebral palsy was found at autopsy to have marked distention of the stomach due to a volvulus. The stomach was viable, and filled with air and fluid and had pushed the left dome of the diaphragm upwards causing marked compression of the left lung with a mediastinal shift to the right (including the heart). There was no evidence of gastric perforation, ischaemic necrosis or peritonitis. Removal of the organ block revealed marked kyphoscoliosis. Histology confirmed the viability of the stomach and biochemistry showed no dehydration. Death in cases of acute gastric volvulus usually occurs because of compromise of the gastric blood supply resulting in ischaemic necrosis with distention from swallowed air and fluid resulting in perforation with lethal peritonitis. Hypovolaemic shock may also occur. However, the current case demonstrates an alternative lethal mechanism, that of respiratory compromise due to marked thoracic organ compression.

  12. Optimization of a pinhole collimator in a SPECT scintillating fiber detector system: a Monte Carlo analysis

    International Nuclear Information System (INIS)

    Hademenos, G.J.

    1994-01-01

    Monte Carlo simulations were used to optimize the dimensions of a lead pinhole collimator in a photon emission computed tomography (SPECT) system consisting of a line of equally spaced Tc-99m point sources and a plastic scintillating fiber detector. The optimization was performed by evaluating the spatial resolution and scanner sensitivity for each source distribution location and collimator parameter variation. An optimal spatial resolution of 0.43 cm FWHM was observed for a source distribution positioned 2.0 cm from the collimated scintillating fiber detection system with a pinhole radius of 1.0 mm and a collimator thickness of 3.0 cm for a 10,000 emission photon simulation. The optimal sensitivity occurred for a source distance of 2.0 cm, a radius of 3.0 mm and a thickness of 3.0 cm. (author)

  13. Accelerated 3D-OSEM image reconstruction using a Beowulf PC cluster for pinhole SPECT

    International Nuclear Information System (INIS)

    Zeniya, Tsutomu; Watabe, Hiroshi; Sohlberg, Antti; Iida, Hidehiro

    2007-01-01

    A conventional pinhole single-photon emission computed tomography (SPECT) with a single circular orbit has limitations associated with non-uniform spatial resolution or axial blurring. Recently, we demonstrated that three-dimensional (3D) images with uniform spatial resolution and no blurring can be obtained by complete data acquired using two-circular orbit, combined with the 3D ordered subsets expectation maximization (OSEM) reconstruction method. However, a long computation time is required to obtain the reconstruction image, because of the fact that 3D-OSEM is an iterative method and two-orbit acquisition doubles the size of the projection data. To reduce the long reconstruction time, we parallelized the two-orbit pinhole 3D-OSEM reconstruction process by using a Beowulf personal computer (PC) cluster. The Beowulf PC cluster consists of seven PCs connected to Gbit Ethernet switches. Message passing interface protocol was utilized for parallelizing the reconstruction process. The projection data in a subset are distributed to each PC. The partial image forward-and back-projected in each PC is transferred to all PCs. The current image estimate on each PC is updated after summing the partial images. The performance of parallelization on the PC cluster was evaluated using two independent projection data sets acquired by a pinhole SPECT system with two different circular orbits. Parallelization using the PC cluster improved the reconstruction time with increasing number of PCs. The reconstruction time of 54 min by the single PC was decreased to 10 min when six or seven PCs were used. The speed-up factor was 5.4. The reconstruction image by the PC cluster was virtually identical with that by the single PC. Parallelization of 3D-OSEM reconstruction for pinhole SPECT using the PC cluster can significantly reduce the computation time, whereas its implementation is simple and inexpensive. (author)

  14. "Planaltina in the Hole of Aluminum": production and consumption of pinhole photographs

    Directory of Open Access Journals (Sweden)

    Juliana Soares Mendes

    2015-08-01

    Full Text Available This article analyzes a photographic exhibition consisting of 15 images created by pinhole technique, which stimulates a critical thinking about photojournalism practice and consumption. The exhibition in the internet (www.fosfoto.com and at the Artistic and Historic Museum of Planaltina (Brazilian Federal District happened in May 2009. Participants were asked to interpret the photographs and rewrite temporary captions. The 1.860 proposed captions indicates the public’s interest to participate, discuss and interpret the pictures.

  15. A clinical gamma camera-based pinhole collimated system for high resolution small animal SPECT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Mejia, J.; Galvis-Alonso, O.Y., E-mail: mejia_famerp@yahoo.com.b [Faculdade de Medicina de Sao Jose do Rio Preto (FAMERP), SP (Brazil). Dept. de Biologia Molecular; Castro, A.A. de; Simoes, M.V. [Faculdade de Medicina de Sao Jose do Rio Preto (FAMERP), SP (Brazil). Dept. de Clinica Medica; Leite, J.P. [Universidade de Sao Paulo (FMRP/USP), Ribeirao Preto, SP (Brazil). Fac. de Medicina. Dept. de Neurociencias e Ciencias do Comportamento; Braga, J. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Div. de Astrofisica

    2010-11-15

    The main objective of the present study was to upgrade a clinical gamma camera to obtain high resolution tomographic images of small animal organs. The system is based on a clinical gamma camera to which we have adapted a special-purpose pinhole collimator and a device for positioning and rotating the target based on a computer-controlled step motor. We developed a software tool to reconstruct the target's three-dimensional distribution of emission from a set of planar projections, based on the maximum likelihood algorithm. We present details on the hardware and software implementation. We imaged phantoms and heart and kidneys of rats. When using pinhole collimators, the spatial resolution and sensitivity of the imaging system depend on parameters such as the detector-to-collimator and detector-to-target distances and pinhole diameter. In this study, we reached an object voxel size of 0.6 mm and spatial resolution better than 2.4 and 1.7 mm full width at half maximum when 1.5- and 1.0-mm diameter pinholes were used, respectively. Appropriate sensitivity to study the target of interest was attained in both cases. Additionally, we show that as few as 12 projections are sufficient to attain good quality reconstructions, a result that implies a significant reduction of acquisition time and opens the possibility for radiotracer dynamic studies. In conclusion, a high resolution single photon emission computed tomography (SPECT) system was developed using a commercial clinical gamma camera, allowing the acquisition of detailed volumetric images of small animal organs. This type of system has important implications for research areas such as Cardiology, Neurology or Oncology. (author)

  16. Depth-of-Interaction Compensation Using a Focused-Cut Scintillator for a Pinhole Gamma Camera

    Science.gov (United States)

    Alhassen, Fares; Kudrolli, Haris; Singh, Bipin; Kim, Sangtaek; Seo, Youngho; Gould, Robert G.; Nagarkar, Vivek V.

    2011-06-01

    Preclinical SPECT offers a powerful means to understand the molecular pathways of drug interactions in animal models by discovering and testing new pharmaceuticals and therapies for potential clinical applications. A combination of high spatial resolution and sensitivity are required in order to map radiotracer uptake within small animals. Pinhole collimators have been investigated, as they offer high resolution by means of image magnification. One of the limitations of pinhole geometries is that increased magnification causes some rays to travel through the detection scintillator at steep angles, introducing parallax errors due to variable depth-of-interaction in scintillator material, especially towards the edges of the detector field of view. These parallax errors ultimately limit the resolution of pinhole preclinical SPECT systems, especially for higher energy isotopes that can easily penetrate through millimeters of scintillator material. A pixellated, focused-cut (FC) scintillator, with its pixels laser-cut so that they are collinear with incoming rays, can potentially compensate for these parallax errors and thus improve the system resolution. We performed the first experimental evaluation of a newly developed focused-cut scintillator. We scanned a Tc-99 m source across the field of view of pinhole gamma camera with a continuous scintillator, a conventional “straight-cut” (SC) pixellated scintillator, and a focused-cut scintillator, each coupled to an electron-multiplying charge coupled device (EMCCD) detector by a fiber-optic taper, and compared the measured full-width half-maximum (FWHM) values. We show that the FWHMs of the focused-cut scintillator projections are comparable to the FWHMs of the thinner SC scintillator, indicating the effectiveness of the focused-cut scintillator in compensating parallax errors.

  17. Depth-of-Interaction Compensation Using a Focused-Cut Scintillator for a Pinhole Gamma Camera.

    Science.gov (United States)

    Alhassen, Fares; Kudrolli, Haris; Singh, Bipin; Kim, Sangtaek; Seo, Youngho; Gould, Robert G; Nagarkar, Vivek V

    2011-06-01

    Preclinical SPECT offers a powerful means to understand the molecular pathways of drug interactions in animal models by discovering and testing new pharmaceuticals and therapies for potential clinical applications. A combination of high spatial resolution and sensitivity are required in order to map radiotracer uptake within small animals. Pinhole collimators have been investigated, as they offer high resolution by means of image magnification. One of the limitations of pinhole geometries is that increased magnification causes some rays to travel through the detection scintillator at steep angles, introducing parallax errors due to variable depth-of-interaction in scintillator material, especially towards the edges of the detector field of view. These parallax errors ultimately limit the resolution of pinhole preclinical SPECT systems, especially for higher energy isotopes that can easily penetrate through millimeters of scintillator material. A pixellated, focused-cut (FC) scintillator, with its pixels laser-cut so that they are collinear with incoming rays, can potentially compensate for these parallax errors and thus improve the system resolution. We performed the first experimental evaluation of a newly developed focused-cut scintillator. We scanned a Tc-99m source across the field of view of pinhole gamma camera with a continuous scintillator, a conventional "straight-cut" (SC) pixellated scintillator, and a focused-cut scintillator, each coupled to an electron-multiplying charge coupled device (EMCCD) detector by a fiber-optic taper, and compared the measured full-width half-maximum (FWHM) values. We show that the FWHMs of the focused-cut scintillator projections are comparable to the FWHMs of the thinner SC scintillator, indicating the effectiveness of the focused-cut scintillator in compensating parallax errors.

  18. Real-time monitoring and verification of in vivo high dose rate brachytherapy using a pinhole camera

    International Nuclear Information System (INIS)

    Duan, Jun; Macey, Daniel J.; Pareek, Prem N.; Brezovich, Ivan A.

    2001-01-01

    We investigated a pinhole imaging system for independent in vivo monitoring and verification of high dose rate (HDR) brachytherapy treatment. The system consists of a high-resolution pinhole collimator, an x-ray fluoroscope, and a standard radiographic screen-film combination. Autofluoroscopy provides real-time images of the in vivo Ir-192 HDR source for monitoring the source location and movement, whereas autoradiography generates a permanent record of source positions on film. Dual-pinhole autoradiographs render stereo-shifted source images that can be used to reconstruct the source dwell positions in three dimensions. The dynamic range and spatial resolution of the system were studied with a polystyrene phantom using a range of source strengths and dwell times. For the range of source activity used in HDR brachytherapy, a 0.5 mm diameter pinhole produced sharp fluoroscopic images of the source within the dynamic range of the fluoroscope. With a source-to-film distance of 35 cm and a 400 speed screen-film combination, the same pinhole yielded well recognizable images of a 281.2 GBq (7.60 Ci) Ir-192 source for dwell times in the typical clinical range of 2 to 400 s. This 0.5 mm diameter pinhole could clearly resolve source positions separated by lateral displacements as small as 1 mm. Using a simple reconstruction algorithm, dwell positions in a phantom were derived from stereo-shifted dual-pinhole images and compared to the known positions. The agreement was better than 1 mm. A preliminary study of a patient undergoing HDR treatment for cervical cancer suggests that the imaging method is clinically feasible. Based on these studies we believe that the pinhole imaging method is capable of providing independent and reliable real-time monitoring and verification for HDR brachytherapy

  19. 3D dual-virtual-pinhole assisted single particle tracking microscopy

    International Nuclear Information System (INIS)

    Ma, Ye; Wang, Yifan; Zhou, Xin; Kuang, Cuifang; Liu, Xu

    2014-01-01

    We propose a novel approach for high-speed, three-dimensional single particle tracking (SPT), which we refer to as dual-virtual-pinhole assisted single particle tracking microscopy (DVPaSPTM). DVPaSPTM system can obtain axial information of the sample without optical or mechanical depth scanning, so as to offer numbers of advantages including faster imaging, improved efficiency and a great reduction of photobleaching and phototoxicity. In addition, by the use of the dual-virtual-pinhole, the effect that the quantum yield exerts to the fluorescent signal can be eliminated, which makes the measurement independent of the surroundings and increases the accuracy of the result. DVPaSPTM system measures the intensity within different virtual pinholes of which the radii are given by the host computer. Axial information of fluorophores can be measured by the axial response curve through the ratio of intensity signals. We demonstrated the feasibility of the proposed method by a series of experiments. Results showed that the standard deviation of the axial measurement was 19.2 nm over a 2.5 μm range with 30 ms temporal resolution. (papers)

  20. System geometry optimization for molecular breast tomosynthesis with focusing multi-pinhole collimators

    Science.gov (United States)

    van Roosmalen, Jarno; Beekman, Freek J.; Goorden, Marlies C.

    2018-01-01

    Imaging of 99mTc-labelled tracers is gaining popularity for detecting breast tumours. Recently, we proposed a novel design for molecular breast tomosynthesis (MBT) based on two sliding focusing multi-pinhole collimators that scan a modestly compressed breast. Simulation studies indicate that MBT has the potential to improve the tumour-to-background contrast-to-noise ratio significantly over state-of-the-art planar molecular breast imaging. The aim of the present paper is to optimize the collimator-detector geometry of MBT. Using analytical models, we first optimized sensitivity at different fixed system resolutions (ranging from 5 to 12 mm) by tuning the pinhole diameters and the distance between breast and detector for a whole series of automatically generated multi-pinhole designs. We evaluated both MBT with a conventional continuous crystal detector with 3.2 mm intrinsic resolution and with a pixelated detector with 1.6 mm pixels. Subsequently, full system simulations of a breast phantom containing several lesions were performed for the optimized geometry at each system resolution for both types of detector. From these simulations, we found that tumour-to-background contrast-to-noise ratio was highest for systems in the 7 mm-10 mm system resolution range over which it hardly varied. No significant differences between the two detector types were found.

  1. X-ray pinhole camera setups used in the Atomki ECR Laboratory for plasma diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Rácz, R., E-mail: rracz@atomki.hu; Biri, S.; Pálinkás, J. [Institute for Nuclear Research (Atomki), Hungarian Academy of Sciences, Bem tér 18/C, H-4026 Debrecen (Hungary); Mascali, D.; Castro, G.; Caliri, C.; Gammino, S. [Instituto Nazionale di Fisica Nucleare—Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Romano, F. P. [Instituto Nazionale di Fisica Nucleare—Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); CNR, Istituto per i Beni Archeologici e Monumentali, Via Biblioteca 4, 95124 Catania (Italy)

    2016-02-15

    Imaging of the electron cyclotron resonance (ECR) plasmas by using CCD camera in combination with a pinhole is a non-destructive diagnostics method to record the strongly inhomogeneous spatial density distribution of the X-ray emitted by the plasma and by the chamber walls. This method can provide information on the location of the collisions between warm electrons and multiple charged ions/atoms, opening the possibility to investigate the direct effect of the ion source tuning parameters to the plasma structure. The first successful experiment with a pinhole X-ray camera was carried out in the Atomki ECR Laboratory more than 10 years ago. The goal of that experiment was to make the first ECR X-ray photos and to carry out simple studies on the effect of some setting parameters (magnetic field, extraction, disc voltage, gas mixing, etc.). Recently, intensive efforts were taken to investigate now the effect of different RF resonant modes to the plasma structure. Comparing to the 2002 experiment, this campaign used wider instrumental stock: CCD camera with a lead pinhole was placed at the injection side allowing X-ray imaging and beam extraction simultaneously. Additionally, Silicon Drift Detector (SDD) and High Purity Germanium (HPGe) detectors were installed to characterize the volumetric X-ray emission rate caused by the warm and hot electron domains. In this paper, detailed comparison study on the two X-ray camera and detector setups and also on the technical and scientific goals of the experiments is presented.

  2. Monte Carlo evaluation of scattering correction methods in 131I studies using pinhole collimator

    International Nuclear Information System (INIS)

    López Díaz, Adlin; San Pedro, Aley Palau; Martín Escuela, Juan Miguel; Rodríguez Pérez, Sunay; Díaz García, Angelina

    2017-01-01

    Scattering is quite important for image activity quantification. In order to study the scattering factors and the efficacy of 3 multiple window energy scatter correction methods during 131 I thyroid studies with a pinhole collimator (5 mm hole) a Monte Carlo simulation (MC) was developed. The GAMOS MC code was used to model the gamma camera and the thyroid source geometry. First, to validate the MC gamma camera pinhole-source model, sensibility in air and water of the simulated and measured thyroid phantom geometries were compared. Next, simulations to investigate scattering and the result of triple energy (TEW), Double energy (DW) and Reduced double (RDW) energy windows correction methods were performed for different thyroid sizes and depth thicknesses. The relative discrepancies to MC real event were evaluated. Results: The accuracy of the GAMOS MC model was verified and validated. The image’s scattering contribution was significant, between 27-40 %. The discrepancies between 3 multiple window energy correction method results were significant (between 9-86 %). The Reduce Double Window methods (15%) provide discrepancies of 9-16 %. Conclusions: For the simulated thyroid geometry with pinhole, the RDW (15 %) was the most effective. (author)

  3. Development of a high sensitivity pinhole type gamma camera using semiconductors for low dose rate fields

    Science.gov (United States)

    Ueno, Yuichiro; Takahashi, Isao; Ishitsu, Takafumi; Tadokoro, Takahiro; Okada, Koichi; Nagumo, Yasushi; Fujishima, Yasutake; Yoshida, Akira; Umegaki, Kikuo

    2018-06-01

    We developed a pinhole type gamma camera, using a compact detector module of a pixelated CdTe semiconductor, which has suitable sensitivity and quantitative accuracy for low dose rate fields. In order to improve the sensitivity of the pinhole type semiconductor gamma camera, we adopted three methods: a signal processing method to set the discriminating level lower, a high sensitivity pinhole collimator and a smoothing image filter that improves the efficiency of the source identification. We tested basic performances of the developed gamma camera and carefully examined effects of the three methods. From the sensitivity test, we found that the effective sensitivity was about 21 times higher than that of the gamma camera for high dose rate fields which we had previously developed. We confirmed that the gamma camera had sufficient sensitivity and high quantitative accuracy; for example, a weak hot spot (0.9 μSv/h) around a tree root could be detected within 45 min in a low dose rate field test, and errors of measured dose rates with point sources were less than 7% in a dose rate accuracy test.

  4. X-ray pinhole camera setups used in the Atomki ECR Laboratory for plasma diagnostics.

    Science.gov (United States)

    Rácz, R; Biri, S; Pálinkás, J; Mascali, D; Castro, G; Caliri, C; Romano, F P; Gammino, S

    2016-02-01

    Imaging of the electron cyclotron resonance (ECR) plasmas by using CCD camera in combination with a pinhole is a non-destructive diagnostics method to record the strongly inhomogeneous spatial density distribution of the X-ray emitted by the plasma and by the chamber walls. This method can provide information on the location of the collisions between warm electrons and multiple charged ions/atoms, opening the possibility to investigate the direct effect of the ion source tuning parameters to the plasma structure. The first successful experiment with a pinhole X-ray camera was carried out in the Atomki ECR Laboratory more than 10 years ago. The goal of that experiment was to make the first ECR X-ray photos and to carry out simple studies on the effect of some setting parameters (magnetic field, extraction, disc voltage, gas mixing, etc.). Recently, intensive efforts were taken to investigate now the effect of different RF resonant modes to the plasma structure. Comparing to the 2002 experiment, this campaign used wider instrumental stock: CCD camera with a lead pinhole was placed at the injection side allowing X-ray imaging and beam extraction simultaneously. Additionally, Silicon Drift Detector (SDD) and High Purity Germanium (HPGe) detectors were installed to characterize the volumetric X-ray emission rate caused by the warm and hot electron domains. In this paper, detailed comparison study on the two X-ray camera and detector setups and also on the technical and scientific goals of the experiments is presented.

  5. Production of a phage-displayed single chain variable fragment ...

    African Journals Online (AJOL)

    Purpose: To develop specific single chain variable fragments (scFv) against infectious bursal disease virus (IBDV) via phage display technology. Methods: Purified viruses were initially applied for iterative panning rounds of scFv phage display libraries. The binding ability of the selected scFv antibody fragments against the ...

  6. An improved plating assay for determination of phage titer | Yang ...

    African Journals Online (AJOL)

    In this study, an improved plating assay was developed for detection of the number of recombinant phage Cap-T7 present in a test solution at a certain dilution point by counting the plaque forming units. The data demonstrated that the improved plating assay is fast, useful, and convenient for the determination of the phage ...

  7. Popping the cork: mechanisms of phage genome ejection

    NARCIS (Netherlands)

    Molineux, I.J.; Panja, D.

    2013-01-01

    Sixty years after Hershey and Chase showed that nucleic acid is the major component of phage particles that is ejected into cells, we still do not fully understand how the process occurs. Advances in electron microscopy have revealed the structure of the condensed DNA confined in a phage capsid, and

  8. Chemical Strategies for the Covalent Modification of Filamentous Phage

    Directory of Open Access Journals (Sweden)

    Matthew B Francis

    2014-12-01

    Full Text Available Historically filamentous bacteriophage have been known to be the workhorse of phage display due to their ability to link genotype to phenotype. More recently, the filamentous phage scaffold has proved to be powerful outside the realms of phage display technology in fields such as molecular imaging, cancer research and materials and vaccine development. The ability of the virion to serve as a platform for a variety of applications heavily relies on the functionalization of the phage coat proteins with a wide variety of functionalities. Genetic modification of the coat proteins has been the most widely used strategy for functionalizing the virion; however complementary chemical modification strategies can help to diversify the range of materials that can be developed. This review emphasizes the recent advances that have been made in the chemical modification of filamentous phage as well as some of the challenges that are involved functionalizing the virion.

  9. Staphylococcus aureus phage types and their correlation to antibiotic resistance

    Directory of Open Access Journals (Sweden)

    Mehndiratta P

    2010-10-01

    Full Text Available Context: Staphylococcus aureus is one of the most devastating human pathogen. The organism has a differential ability to spread and cause outbreak of infections. Characterization of these strains is important to control the spread of infection in the hospitals as well as in the community. Aim: To identify the currently existing phage groups of Staphylococcus aureus, their prevalence and resistance to antibiotics. Materials and Methods: Study was undertaken on 252 Staphylococcus aureus strains isolated from clinical samples. Strains were phage typed and their resistance to antibiotics was determined following standard microbiological procedures. Statistical Analysis: Chi square test was used to compare the antibiotic susceptibility between methicillin resistant Staph. aureus (MRSA and methicillin sensitive S. aureus (MSSA strains. Results: Prevalence of MRSA and MSSA strains was found to be 29.36% and 70.65% respectively. Of these 17.56% of MRSA and 40.44% of MSSA strains were community acquired. All the MSSA strains belonging to phage type 81 from the community were sensitive to all the antibiotics tested including clindamycin and were resistant to penicillin. Forty five percent strains of phage group III and 39% of non-typable MRSA strains from the hospital were resistant to multiple antibiotics. Conclusion: The study revealed that predominant phage group amongst MRSA strains was phage group III and amongst MSSA from the community was phage group NA (phage type 81. MSSA strains isolated from the community differed significantly from hospital strains in their phage type and antibiotic susceptibility. A good correlation was observed between community acquired strains of phage type 81 and sensitivity to gentamycin and clindamycin.

  10. Protein Expression Modifications in Phage-Resistant Mutants of Aeromonas salmonicida after AS-A Phage Treatment

    Directory of Open Access Journals (Sweden)

    Catarina Moreirinha

    2018-03-01

    Full Text Available The occurrence of infections by pathogenic bacteria is one of the main sources of financial loss for the aquaculture industry. This problem often cannot be solved with antibiotic treatment or vaccination. Phage therapy seems to be an alternative environmentally-friendly strategy to control infections. Recognizing the cellular modifications that bacteriophage therapy may cause to the host is essential in order to confirm microbial inactivation, while understanding the mechanisms that drive the development of phage-resistant strains. The aim of this work was to detect cellular modifications that occur after phage AS-A treatment in A. salmonicida, an important fish pathogen. Phage-resistant and susceptible cells were subjected to five successive streak-plating steps and analysed with infrared spectroscopy, a fast and powerful tool for cell study. The spectral differences of both populations were investigated and compared with a phage sensitivity profile, obtained through the spot test and efficiency of plating. Changes in protein associated peaks were found, and these results were corroborated by 1-D electrophoresis of intracellular proteins analysis and by phage sensitivity profiles. Phage AS-A treatment before the first streaking-plate step clearly affected the intracellular proteins expression levels of phage-resistant clones, altering the expression of distinct proteins during the subsequent five successive streak-plating steps, making these clones recover and be phenotypically more similar to the sensitive cells.

  11. Phase variable expression of a single phage receptor in Campylobacter jejuni NCTC12662 influences sensitivity toward several diverse CPS-dependent phages

    DEFF Research Database (Denmark)

    Gencay, Yilmaz Emre; Sørensen, Martine C.H.; Wenzel, Cory Q.

    2018-01-01

    Campylobacter jejuni NCTC12662 is sensitive to infection by many Campylobacter bacteriophages. Here we used this strain to investigate the molecular mechanism behind phage resistance development when exposed to a single phage and demonstrate how phase variable expression of one surface component...... influences phage sensitivity against many diverse C. jejuni phages. When C. jejuni NCTC12662 was exposed to phage F207 overnight, 25% of the bacterial cells were able to grow on a lawn of phage F207, suggesting that resistance develops at a high frequency. One resistant variant, 12662R, was further...... characterized and shown to be an adsorption mutant. Plaque assays using our large phage collection showed that seven out of 36 diverse capsular polysaccharide (CPS)-dependent phages could not infect 12662R, whereas the remaining phages formed plaques on 12662R with reduced efficiencies. Analysis of the CPS...

  12. The XXIIIrd Phage/Virus Assembly Meeting.

    Science.gov (United States)

    Serwer, Philip

    2014-01-01

    The XXIIIrd Phage/Virus Assembly (PVA) meeting returned to its birthplace in Lake Arrowhead, CA on September 8-13, 2013 (Fig. 1). The original meeting occurred in 1968, organized by Bob Edgar (Caltech, Pasadena, CA USA), Fred Eiserling (University of California, Los Angeles, Los Angeles, CA USA) and Bill Wood (Caltech, Pasadena, CA USA). The organizers of the 2013 meeting were Bill Gelbart (University of California, Los Angeles, Los Angeles, CA USA) and Jack Johnson (Scripps Research Institute, La Jolla, CA USA). This meeting specializes in an egalitarian format. Students are distinguished from senior faculty primarily by the signs of age. With the exception of historically based introductory talks, all talks were allotted the same time and freedom. This tradition began when the meeting was phage-only and has been continued now that all viruses are included. Many were the animated conversations about basic questions. New and international participants were present, a sign that the field has significant attraction, as it should, based on details below. The meeting was also characterized by a sense of humor and generally good times, a chance to both enjoy the science and forget the funding malaise to which many participants are exposed. I will present some of the meeting content, without attempting to be comprehensive.

  13. Exploration of Phage-Host Interactions in Fish Pathogen Vibrio anguillarum and Anti-Phage Defense Strategies

    DEFF Research Database (Denmark)

    Tan, Demeng

    The disease vibriosis is caused by the bacterial pathogen Vibrio anguillarum and results in large losses in aquaculture both in Denmark and around the world. Antibiotics have been widely used in antimicrobial prophylaxis and treatment of vibriosis. Recently, numerous multidrug-resistant strains...... of V. anguillarum have been isolated, indicating that antibiotic use has to be restricted and alternatives have to be developed. Lytic phages have been demonstrated to play an essential role in preventing bacterial infection. However, phages are also known to play a critical role in the evolution...... of bacterial pathogenicity development. Therefore, successful application of phage therapy in the treatment of vibriosis requires a detailed understanding of phage-host interactions, especially with regards to anti-phage defense mechanisms in the host. Part I. As a first approach, 24 V. anguillarum and 13...

  14. Vibrio vulnificus phage PV94 is closely related to temperate phages of V. cholerae and other Vibrio species.

    Directory of Open Access Journals (Sweden)

    Mark Pryshliak

    Full Text Available BACKGROUND: Vibrio vulnificus is an important pathogen which can cause serious infections in humans. Yet, there is limited knowledge on its virulence factors and the question whether temperate phages might be involved in pathogenicity, as is the case with V. cholerae. Thus far, only two phages (SSP002 and VvAW1 infecting V. vulnificus have been genetically characterized. These phages were isolated from the environment and are not related to Vibrio cholerae phages. The lack of information on temperate V. vulnificus phages prompted us to isolate those phages from lysogenic strains and to compare them with phages of other Vibrio species. RESULTS: In this study the temperate phage PV94 was isolated from a V. vulnificus biotype 1 strain by mitomycin C induction. PV94 is a myovirus whose genome is a linear double-stranded DNA of 33,828 bp with 5'-protruding ends. Sequence analysis of PV94 revealed a modular organization of the genome. The left half of the genome comprising the immunity region and genes for the integrase, terminase and replication proteins shows similarites to V. cholerae kappa phages whereas the right half containing genes for structural proteins is closely related to a prophage residing in V. furnissii NCTC 11218. CONCLUSION: We present the first genomic sequence of a temperate phage isolated from a human V. vulnificus isolate. The sequence analysis of the PV94 genome demonstrates the wide distribution of closely related prophages in various Vibrio species. Moreover, the mosaicism of the PV94 genome indicates a high degree of horizontal genetic exchange within the genus Vibrio, by which V. vulnificus might acquire virulence-associated genes from other species.

  15. Electroshock weapons can be lethal!

    Science.gov (United States)

    Lundquist, Marjorie

    2008-03-01

    Electroshock weapons (EWs)-stun guns, tasers, riot shields-are electroconductive devices designed to safely incapacitate healthy men neuromuscularly, so they are called nonlethal or less-lethal. EW firms seeking large nonmilitary markets targeted law enforcement and corrections personnel, who began using EWs in prisons/jails and on public patrol in 1980 in the USA. This shifted the EW-shocked population from healthy soldiers to a heterogeneous mix of both sexes, ages 6-92, in a wide variety of health conditions! An EW operates by disrupting normal physiological processes, producing transient effects in healthy people. But if a person's health is sufficiently compromised, the margin of safety can be lost, resulting in death or permanent health problems. 325 people have died after EW shock since 1980. Did the EW cause these deaths? Evidence indicates that EWs do play a causal role in most such deaths. EWs can be lethal for people in diabetic shock^1 (hypoglycemia), which may be why Robert Dziekanski-a Polish immigrant to Canada-died so quickly after he was tasered at Vancouver Airport: not having eaten for over 10 hours, he likely was severely hypoglycemic. The EW death rate in North America is 30 times higher than need be, because EW users have not been properly trained to use EWs on a heterogeneous population safely! ^1J. Clinical Engineering 30(3):111(2005).

  16. Wholebody and pinhole bone scan manifestations of reiter's syndorme: distribution pattern and specific and early signs

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. H.; Chung, S. K.; Park, Y. H.; Lee, S. Y.; Sohn, H. S.; Han, B. H.; Bahk, Y. W. [College of Medicine, Catholic Univ., Seoul (Korea, Republic of)

    1998-07-01

    We wish to describe the characteristics panoramic wholebody bone distribution, and specific and preradiographic pinhole bone scan signs of Reiter's syndrome(RS) featured by pauciarthritis and enthesopathies in and about weight-bearing joints of the lower extremities and axial bones. We analyzed 55 sets of wholebody and pinhole bone scintigraphs of 55 patients with RS. The population was 44 men and 11 women with age ranging from 15 to 52 yr (mean=29.3). The scintigraphy was performed 2-2.5 hr pi of Tc-99m-HDP using a single-head gamma camera with a LEHR collimator and a 4-mm pinhole collimator for the wholebody and pinhole scintigraphy, respectively. We found 223 lesions with increased tracer uptake in total. Wholebody scans showed asymmetric pauciarticular distribution in weight bearing joints and periarticular entheses in the lower extremities in 63.2% (calcaneus=24.2%, ankle=8.1%, tibia=8.1% and others). The sternum, sacroiliac joint and spine were involved in 8.5%, 5.8% and 4.5%, respectively. Pinhole scan portrayed many specific signs including the 'tear-drop' sign of paravertebral ossification. 'whiskers' sign of femoral osteophytes and 'knuckle bone' sign of sausage digit. Twenty-four lesions (10.8%) showed preradiogrpahic signs in symptomatic ehthesopathies mostly in the calcaneus and proximal tibia. Nine cases with calcaneal enthesopathies and four cases with proximal tibial enthesopathy without radiographic bone change showed intense tracer uptake. Wholebody and pinhole magnification scans were useful in studying RS. The asymmetric pauciarticular distribution in the weight-bearing bones with enthesopathies was characteristic. Pinhole scan portrayed many specific signs and was sensitive permitting accurate preradiographic diagnosis in many cases.

  17. Whole-body and pinhole bone scintigraphic manifestations of Reiter`s syndrome: distribution patterns and early and characteristic signs

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung-Hoon; Chung, Soo-Kyo; Park, Young-Ha; Lee, Sung-Yong; Sohn, Hyung-Sun [Department of Nuclear Medicine, Catholic University Hospitals, Seoul (Korea, Republic of); Bahk, Yong-Whee [Department of Radiology, Samsung Cheil Hospital, Sungkyunkwan University College of Medicine, Seoul (Korea, Republic of)

    1999-02-01

    The characteristic whole-body and pinhole scintigraphic manifestations of osteo-enthesopathy and arthropathy in Reiter`s syndrome (RS) are described, with an emphasis on early diagnosis. We analysed 59 sets of whole-body and pinhole bone scintigrams of 59 patients with RS. The population comprised 47 men and 12 women with an age range from 15 to 53 years (mean=29.4). Bone scintigraphy was carried out 2-2.5 h after intravenous injection of technetium-99m hydroxydiphosphonate using a single-head gamma camera (Siemens Orbiter Model 6601) with a low-energy high-resolution and a 4-mm pinhole collimator for whole-body and pinhole scintigraphy, respectively. In total 262 lesions of osteo-enthesopathy and arthritis were detected on 59 whole-body scintigrams, an incidence of 4.4 lesions per patient. As anticipated, the lesional distribution was asymmetrical: 68% were in the lower limb skeleton and 32% in the axial and upper limb skeleton. Pinhole bone scintigraphy, applied selectively to one region of interest in each case, enabled us to accurately diagnose arthritis and osteo-enthesopathy. It was noteworthy that osteo-enthesopathy, alone or in combination with arthritis, occurred in 78.9%, and had a strong predilection for the foot bones, especially the calcaneus (25.6%). Pinhole scintigraphy detected enthesopathy in the absence of radiographic alteration in 14.1% of cases and portrayed characteristic signs of RS in 6.9%. Whole-body bone scintigraphy augmented with pinhole scintigraphy was found to be useful in order to panoramically display the systemic involvement pattern, to assess the characteristic bone and articular alterations and to detect early signs of RS. (orig.) With 10 figs., 3 tabs., 19 refs.

  18. Coevolution of CRISPR bacteria and phage in 2 dimensions

    Science.gov (United States)

    Han, Pu; Deem, Michael

    2014-03-01

    CRISPR (cluster regularly interspaced short palindromic repeats) is a newly discovered adaptive, heritable immune system of prokaryotes. It can prevent infection of prokaryotes by phage. Most bacteria and almost all archae have CRISPR. The CRISPR system incorporates short nucleotide sequences from viruses. These incorporated sequences provide a historical record of the host and predator coevolution. We simulate the coevolution of bacteria and phage in 2 dimensions. Each phage has multiple proto-spacers that the bacteria can incorporate. Each bacterium can store multiple spacers in its CRISPR. Phages can escape recognition by the CRISPR system via point mutation or recombination. We will discuss the different evolutionary consequences of point mutation or recombination on the coevolution of bacteria and phage. We will also discuss an intriguing ``dynamic phase transition'' in the number of phage as a function of time and mutation rate. We will show that due to the arm race between phages and bacteria, the frequency of spacers and proto-spacers in a population can oscillate quite rapidly.

  19. Identifying Bacterial Immune Evasion Proteins Using Phage Display.

    Science.gov (United States)

    Fevre, Cindy; Scheepmaker, Lisette; Haas, Pieter-Jan

    2017-01-01

    Methods aimed at identification of immune evasion proteins are mainly rely on in silico prediction of sequence, structural homology to known evasion proteins or use a proteomics driven approach. Although proven successful these methods are limited by a low efficiency and or lack of functional identification. Here we describe a high-throughput genomic strategy to functionally identify bacterial immune evasion proteins using phage display technology. Genomic bacterial DNA is randomly fragmented and ligated into a phage display vector that is used to create a phage display library expressing bacterial secreted and membrane bound proteins. This library is used to select displayed bacterial secretome proteins that interact with host immune components.

  20. Pinhole aperture point backlighter development experiments on Trident, 9-13, 2001

    International Nuclear Information System (INIS)

    Lanier, N.E.; Murphy, Thomas J.

    2001-01-01

    Pinhole aperture point backlighter (PAPBL) imaging has been used on experiments on Omega, but results have been compromised by large backgrounds. This technique has advantages over traditional area backlighting/pinhole imaging, and the Omega experiments could benefit from this capability, but Omega time is expensive and not the place for developing diagnostic techniques if they can be developed on Trident instead. PAPBL, shot from Direct Drive Cylinder Mix experiments on Omega (DDCYLMIX 00-1, January 18 and 19, 2000). (See LA-UR-00-4187, Post-Shot Report, Direct Drive Cylinder Mix). In this campaign, they used Trident to obtain clean PAPBL images. Having accomplished that, they attempted to replicate the noise environment of Omega by producing hot electrons and having them impinge on material to produce high-energy x-rays similar to those that might be produced by hot electrons impinging on diagnostics or target positioner components on Omega. Backlighter target design was based, to some degree, on that shown by Bullock et al. at the 42nd Annual APS-DPP Meeting in Quebec City, Quebec, Canada, October 23-27, 2000. (A.B. Bullock et al., Bull. Am. Phys. Soc. 45,(7) 359 (2000); A.B. Bullock et al., Rev. Sci. Instrum. 72, 690 (2001).) We accomplished this to some degree and then attempted, with some success, to obtain a good PAPBL image in the presence of this noise. Results of this work suggest methods that might reduce the background noise in Omega PAPBL images. The goals are to obtain a pinhole aperture point backlighter (PAPBL) image on Trident and develop a method to simulate the high-energy background contribution to PAPBL imnages seen on Omega experients in order to allow future experiments to optimize signal-to-noise in PAPBL imaging.

  1. Robust Pinhole-free Li3N Solid Electrolyte Grown from Molten Lithium

    Directory of Open Access Journals (Sweden)

    Yanbin Li

    2017-12-01

    Full Text Available Lithium metal is the ultimate anode choice for high energy density rechargeable lithium batteries. However, it suffers from inferior electrochemical performance and safety issues due to its high reactivity and the growth of lithium dendrites. It has long been desired to develop a materials coating on Li metal, which is pinhole-free, mechanically robust without fracture during Li metal deposition and stripping, and chemically stable against Li metal and liquid electrolytes, all while maintaining adequate ionic conductivity. However, such an ideal material coating has yet to be found. Here we report a novel synthesis method by reacting clean molten lithium foil directly with pure nitrogen gas to generate instantaneously a pinhole-free and ionically conductive α-Li3N film directly bonded onto Li metal foil. The film consists of highly textured large Li3N grains (tens of μm with (001 crystalline planes parallel to the Li metal surface. The bonding between textured grains is strong, resulting in a mechanically robust film which does not crack even when bent to a 0.8 cm curvature radius and is found to maintain pinhole-free coverage during Li metal deposition and stripping. The measured ionic conductivity is up to 5.2 × 10–4 S cm–1, sufficient for maintaining regular current densities for controllable film thicknesses ranging from 2 to 30 μm. This Li3N coating is chemically stable, isolating the reactive metallic lithium from liquid electrolyte, prevents continuous electrolyte consumption during battery cycling, and promotes dendrite-free uniform lithium plating/stripping underneath. We demonstrated Li|Li4Ti5O12 cells with stable and flat potential profiles for 500 cycles without capacity decay or an increase in potential hysteresis.

  2. Imaging of dopamine transporters in rats using high-resolution pinhole single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Booij, Jan; Bruin, Kora de; Habraken, Jan B.A. [Department of Nuclear Medicine, F2N, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam (Netherlands); Voorn, Pieter [Department of Anatomy, Vrije Universiteit Medical Center, Amsterdam (Netherlands)

    2002-09-01

    To date, the vast majority of investigations on the dopaminergic system in small animals have been in vitro studies. In comparison with in vitro studies, single-photon emission tomography (SPET) or positron emission tomography (PET) imaging of the dopaminergic system in small animals has the advantage of permitting repeated studies within the same group of animals. Dopamine transporter imaging is a valuable non-invasive tool with which to investigate the integrity of dopaminergic neurons. The purpose of this study was to investigate the feasibility of assessing dopamine transporter density semi-quantitatively in rats using a recently developed high-resolution pinhole SPET system. This system was built exclusively for imaging of small animals. In this unique single-pinhole system, the animal rotates instead of the collimated detector. The system has proven to have a high spatial resolution. We performed SPET imaging with [{sup 123}I]FP-CIT to quantify striatal dopamine transporters in rat brain. In all seven studied control rats, symmetrical striatal binding to dopamine transporters was seen 2 h after injection of the radiotracer, with striatal-to-cerebellar binding ratios of approximately 3.5. In addition, test/retest variability of the striatal-to-cerebellar binding ratios was studied and found to be 14.5%. Finally, in unilaterally 6-hydroxydopamine-lesioned rats, striatal binding was only visible on the non-lesioned side. Quantitative analysis revealed that striatal-to-cerebellar SPET ratios were significantly lower on the lesioned (mean binding ratio 2.2{+-}0.2) than on the non-lesioned (mean ratio 3.1{+-}0.4) side. The preliminary results of this study indicate that semi-quantitative assessment of striatal dopamine transporter density using our recently developed high-resolution single-pinhole SPET system is feasible in living rat brain. (orig.)

  3. Phage-Bacterial Dynamics with Spatial Structure: Self Organization around Phage Sinks Can Promote Increased Cell Densities.

    Science.gov (United States)

    Bull, James J; Christensen, Kelly A; Scott, Carly; Jack, Benjamin R; Crandall, Cameron J; Krone, Stephen M

    2018-01-29

    Bacteria growing on surfaces appear to be profoundly more resistant to control by lytic bacteriophages than do the same cells grown in liquid. Here, we use simulation models to investigate whether spatial structure per se can account for this increased cell density in the presence of phages. A measure is derived for comparing cell densities between growth in spatially structured environments versus well mixed environments (known as mass action). Maintenance of sensitive cells requires some form of phage death; we invoke death mechanisms that are spatially fixed, as if produced by cells. Spatially structured phage death provides cells with a means of protection that can boost cell densities an order of magnitude above that attained under mass action, although the effect is sometimes in the opposite direction. Phage and bacteria self organize into separate refuges, and spatial structure operates so that the phage progeny from a single burst do not have independent fates (as they do with mass action). Phage incur a high loss when invading protected areas that have high cell densities, resulting in greater protection for the cells. By the same metric, mass action dynamics either show no sustained bacterial elevation or oscillate between states of low and high cell densities and an elevated average. The elevated cell densities observed in models with spatial structure do not approach the empirically observed increased density of cells in structured environments with phages (which can be many orders of magnitude), so the empirical phenomenon likely requires additional mechanisms than those analyzed here.

  4. Microlens Array/Pinhole Mask to Suppress Starlight for Direct Exoplanet Detection

    Science.gov (United States)

    Zimmerman, Neil

    Direct imaging of habitable exoplanets is a key priority of NASA’s Astrophysics roadmap, “Enduring Quests, Daring Visions.” A coronagraphic starlight suppression system situated on a large space telescope offers a viable path to achieving this goal. This type of instrument is central to both the LUVOIR and HabEx mission concepts currently under study for the 2020 Decadal Survey. To directly image an Earth-like exoplanet, an instrument must be sensitive to objects ten billion times dimmer than their parent star. Advanced coronagraphs are designed to modify the shape of the star’s image so that it does not overwhelm the planet's light. Coronagraphs are complex to design and fabricate, tend to sacrifice a significant portion of the exoplanet light entering the telescope, and are highly sensitive to errors in the telescope. The proposed work reduces the demands on the coronagraph and its sensitivity to errors in the telescope, by changing how we implement optics in the spectrograph following the coronagraph. Through optical analysis and modeling, we have found that a microlens array with a specially arranged pattern of pinholes can suppress residual starlight in the scientific image after the coronagraph by more than two orders of magnitude. This added layer of starlight rejection could be used to relax the extreme observatory stability requirements for exo-Earth imaging applications, for example shifting the wavefront stability requirement from a few picometers to a few nanometers. Ultimately this translates to the instrument detecting and spectrally characterizing more exoplanets than a conventional coronagraph system. This microlens/pinhole concept is also compatible with starshadebased starlight suppression systems. The proposed microlens/pinhole device is entirely passive and augments the performance of existing coronagraph designs, while potentially reducing their cost and risk for mission implementation. Our APRA proposal would support a testbed

  5. Reconstruction of multiple-pinhole micro-SPECT data using origin ensembles.

    Science.gov (United States)

    Lyon, Morgan C; Sitek, Arkadiusz; Metzler, Scott D; Moore, Stephen C

    2016-10-01

    The authors are currently developing a dual-resolution multiple-pinhole microSPECT imaging system based on three large NaI(Tl) gamma cameras. Two multiple-pinhole tungsten collimator tubes will be used sequentially for whole-body "scout" imaging of a mouse, followed by high-resolution (hi-res) imaging of an organ of interest, such as the heart or brain. Ideally, the whole-body image will be reconstructed in real time such that data need only be acquired until the area of interest can be visualized well-enough to determine positioning for the hi-res scan. The authors investigated the utility of the origin ensemble (OE) algorithm for online and offline reconstructions of the scout data. This algorithm operates directly in image space, and can provide estimates of image uncertainty, along with reconstructed images. Techniques for accelerating the OE reconstruction were also introduced and evaluated. System matrices were calculated for our 39-pinhole scout collimator design. SPECT projections were simulated for a range of count levels using the MOBY digital mouse phantom. Simulated data were used for a comparison of OE and maximum-likelihood expectation maximization (MLEM) reconstructions. The OE algorithm convergence was evaluated by calculating the total-image entropy and by measuring the counts in a volume-of-interest (VOI) containing the heart. Total-image entropy was also calculated for simulated MOBY data reconstructed using OE with various levels of parallelization. For VOI measurements in the heart, liver, bladder, and soft-tissue, MLEM and OE reconstructed images agreed within 6%. Image entropy converged after ∼2000 iterations of OE, while the counts in the heart converged earlier at ∼200 iterations of OE. An accelerated version of OE completed 1000 iterations in <9 min for a 6.8M count data set, with some loss of image entropy performance, whereas the same dataset required ∼79 min to complete 1000 iterations of conventional OE. A combination of the two

  6. Differential diagnosis of trampoline fracture from osteomyelitis by bone scan with pinhole collimator.

    Science.gov (United States)

    Gauthé, Mathieu; Mestas, Danielle; Canavese, Federico; Samba, Antoine; Cachin, Florent

    2014-02-01

    A 2-year-old girl with recent history of trampoline fall presented to the A&E Department for complete functional impairment of the left lower extremity and fever. Blood examination revealed an inflammatory syndrome, while plain radiographs were normal. As magnetic resonance imaging was unavailable, a bone scintigraphy was performed. While standard acquisition found an intense uptake focused on the left proximal tibial metaphysis whose appearance was suggestive of acute hematogenous osteomyelitis, complementary acquisition with the pinhole collimator demonstrated that this abnormal uptake was clearly distinct from the cartilage growth plate. One month follow-up radiographs showed a fracture that confirmed the diagnosis of trampoline fracture.

  7. Effect of lethal and sub-lethal concentrations of tobacco (Nicotiana ...

    African Journals Online (AJOL)

    Lethal and sub-lethal bioassays on Clarias gariepinus were conducted to evaluate the toxicity of tobacco (Nicotiana tobaccum) leaf dust on weight gain and haematological indices of Clarias gariepinus (mean weight 10.5±0.70g) in glass aquaria with aeration system. The concentrations used during the lethal exposure are: ...

  8. Plasmids and packaging cell lines for use in phage display

    Science.gov (United States)

    Bradbury, Andrew M.

    2012-07-24

    The invention relates to a novel phagemid display system for packaging phagemid DNA into phagemid particles which completely avoids the use of helper phage. The system of the invention incorporates the use of bacterial packaging cell lines which have been transformed with helper plasmids containing all required phage proteins but not the packaging signals. The absence of packaging signals in these helper plasmids prevents their DNA from being packaged in the bacterial cell, which provides a number of significant advantages over the use of both standard and modified helper phage. Packaged phagemids expressing a protein or peptide of interest, in fusion with a phage coat protein such as g3p, are generated simply by transfecting phagemid into the packaging cell line.

  9. Metagenomic recovery of phage genomes of uncultured freshwater actinobacteria.

    Science.gov (United States)

    Ghai, Rohit; Mehrshad, Maliheh; Mizuno, Carolina Megumi; Rodriguez-Valera, Francisco

    2017-01-01

    Low-GC Actinobacteria are among the most abundant and widespread microbes in freshwaters and have largely resisted all cultivation efforts. Consequently, their phages have remained totally unknown. In this work, we have used deep metagenomic sequencing to assemble eight complete genomes of the first tailed phages that infect freshwater Actinobacteria. Their genomes encode the actinobacterial-specific transcription factor whiB, frequently found in mycobacteriophages and also in phages infecting marine pelagic Actinobacteria. Its presence suggests a common and widespread strategy of modulation of host transcriptional machinery upon infection via this transcriptional switch. We present evidence that some whiB-carrying phages infect the acI lineage of Actinobacteria. At least one of them encodes the ADP-ribosylating component of the widespread bacterial AB toxins family (for example, clostridial toxin). We posit that the presence of this toxin reflects a 'trojan horse' strategy, providing protection at the population level to the abundant host microbes against eukaryotic predators.

  10. Primary isolation strain determines both phage type and receptors recognised by Campylobacter jejuni bacteriophages.

    Directory of Open Access Journals (Sweden)

    Martine C Holst Sørensen

    Full Text Available In this study we isolated novel bacteriophages, infecting the zoonotic bacterium Campylobacter jejuni. These phages may be used in phage therapy of C. jejuni colonized poultry to prevent spreading of the bacteria to meat products causing disease in humans. Many C. jejuni phages have been isolated using NCTC12662 as the indicator strain, which may have biased the selection of phages. A large group of C. jejuni phages rely on the highly diverse capsular polysaccharide (CPS for infection and recent work identified the O-methyl phosphoramidate modification (MeOPN of CPS as a phage receptor. We therefore chose seven C. jejuni strains each expressing different CPS structures as indicator strains in a large screening for phages in samples collected from free-range poultry farms. Forty-three phages were isolated using C. jejuni NCTC12658, NCTC12662 and RM1221 as host strains and 20 distinct phages were identified based on host range analysis and genome restriction profiles. Most phages were isolated using C. jejuni strains NCTC12662 and RM1221 and interestingly phage genome size (140 kb vs. 190 kb, host range and morphological appearance correlated with the isolation strain. Thus, according to C. jejuni phage grouping, NCTC12662 and NCTC12658 selected for CP81-type phages, while RM1221 selected for CP220-type phages. Furthermore, using acapsular ∆kpsM mutants we demonstrated that phages isolated on NCTC12658 and NCTC12662 were dependent on the capsule for infection. In contrast, CP220-type phages isolated on RM1221 were unable to infect non-motile ∆motA mutants, hence requiring motility for successful infection. Hence, the primary phage isolation strain determines both phage type (CP81 or CP220 as well as receptors (CPS or flagella recognised by the isolated phages.

  11. Degradation sources of CdTe thin film PV: CdCl{sub 2} residue and shunting pinholes

    Energy Technology Data Exchange (ETDEWEB)

    Gorji, Nima E. [University of Bologna, Department of Electrical, Electronics and Information Engineering, Bologna (Italy)

    2014-09-15

    The present work considers two observable phenomena through the experimental fabrication and electrical characterization of the rf-sputtered CdS/CdTe thin film solar cells that extremely reduce the overall conversion efficiency of the device: CdCl{sub 2} residue on the surface of the semiconductor and shunting pinholes. The former happens through nonuniform treatment of the As-deposited solar cells before annealing at high temperature and the latter occurs by shunting pinholes when the cell surface is shunted by defects, wire-like pathways or scratches on the metallic back contact caused from the external contacts. Such physical problems may be quite common in the experimental activities and reduce the performance down to 4-5 % which leads to dismantle the device despite its precise fabrication. We present our electrical characterization on the samples that received wet CdCl{sub 2} surface treatment (uniform or nonuniform) and are damaged by the pinholes. (orig.)

  12. Phage display as a promising approach for vaccine development

    OpenAIRE

    Aghebati-Maleki, Leili; Bakhshinejad, Babak; Baradaran, Behzad; Motallebnezhad, Morteza; Aghebati-Maleki, Ali; Nickho, Hamid; Yousefi, Mehdi; Majidi, Jafar

    2016-01-01

    Bacteriophages are specific antagonists to bacterial hosts. These viral entities have attracted growing interest as optimal vaccine delivery vehicles. Phages are well-matched for vaccine design due to being highly stable under harsh environmental conditions, simple and inexpensive large scale production, and potent adjuvant capacities. Phage vaccines have efficient immunostimulatory effects and present a high safety profile because these viruses have made a constant relationship with the mamm...

  13. Killing cancer cells by targeted drug-carrying phage nanomedicines

    Directory of Open Access Journals (Sweden)

    Yacoby Iftach

    2008-04-01

    Full Text Available Abstract Background Systemic administration of chemotherapeutic agents, in addition to its anti-tumor benefits, results in indiscriminate drug distribution and severe toxicity. This shortcoming may be overcome by targeted drug-carrying platforms that ferry the drug to the tumor site while limiting exposure to non-target tissues and organs. Results We present a new form of targeted anti-cancer therapy in the form of targeted drug-carrying phage nanoparticles. Our approach is based on genetically-modified and chemically manipulated filamentous bacteriophages. The genetic manipulation endows the phages with the ability to display a host-specificity-conferring ligand. The phages are loaded with a large payload of a cytotoxic drug by chemical conjugation. In the presented examples we used anti ErbB2 and anti ERGR antibodies as targeting moieties, the drug hygromycin conjugated to the phages by a covalent amide bond, or the drug doxorubicin conjugated to genetically-engineered cathepsin-B sites on the phage coat. We show that targeting of phage nanomedicines via specific antibodies to receptors on cancer cell membranes results in endocytosis, intracellular degradation, and drug release, resulting in growth inhibition of the target cells in vitro with a potentiation factor of >1000 over the corresponding free drugs. Conclusion The results of the proof-of concept study presented here reveal important features regarding the potential of filamentous phages to serve as drug-delivery platform, on the affect of drug solubility or hydrophobicity on the target specificity of the platform and on the effect of drug release mechanism on the potency of the platform. These results define targeted drug-carrying filamentous phage nanoparticles as a unique type of antibody-drug conjugates.

  14. Killing cancer cells by targeted drug-carrying phage nanomedicines

    Science.gov (United States)

    Bar, Hagit; Yacoby, Iftach; Benhar, Itai

    2008-01-01

    Background Systemic administration of chemotherapeutic agents, in addition to its anti-tumor benefits, results in indiscriminate drug distribution and severe toxicity. This shortcoming may be overcome by targeted drug-carrying platforms that ferry the drug to the tumor site while limiting exposure to non-target tissues and organs. Results We present a new form of targeted anti-cancer therapy in the form of targeted drug-carrying phage nanoparticles. Our approach is based on genetically-modified and chemically manipulated filamentous bacteriophages. The genetic manipulation endows the phages with the ability to display a host-specificity-conferring ligand. The phages are loaded with a large payload of a cytotoxic drug by chemical conjugation. In the presented examples we used anti ErbB2 and anti ERGR antibodies as targeting moieties, the drug hygromycin conjugated to the phages by a covalent amide bond, or the drug doxorubicin conjugated to genetically-engineered cathepsin-B sites on the phage coat. We show that targeting of phage nanomedicines via specific antibodies to receptors on cancer cell membranes results in endocytosis, intracellular degradation, and drug release, resulting in growth inhibition of the target cells in vitro with a potentiation factor of >1000 over the corresponding free drugs. Conclusion The results of the proof-of concept study presented here reveal important features regarding the potential of filamentous phages to serve as drug-delivery platform, on the affect of drug solubility or hydrophobicity on the target specificity of the platform and on the effect of drug release mechanism on the potency of the platform. These results define targeted drug-carrying filamentous phage nanoparticles as a unique type of antibody-drug conjugates. PMID:18387177

  15. “French Phage Network”—Second Meeting Report

    Science.gov (United States)

    Torres-Barceló, Clara; Kaltz, Oliver; Froissart, Rémy; Gandon, Sylvain; Ginet, Nicolas; Ansaldi, Mireille

    2017-01-01

    The study of bacteriophages (viruses of bacteria) includes a variety of approaches, such as structural biology, genetics, ecology, and evolution, with increasingly important implications for therapeutic and industrial uses. Researchers working with phages in France have recently established a network to facilitate the exchange on complementary approaches, but also to engage new collaborations. Here, we provide a summary of the topics presented during the second meeting of the French Phage Network that took place in Marseille in November 2016. PMID:28430166

  16. A study of the decoding of multiple pinhole coded aperture RI tomographic images

    International Nuclear Information System (INIS)

    Hasegawa, Takeo; Kobayashi, Akitoshi; Nishiyama, Yutaka; Akagi, Kiyoshi; Uehata, Hiroshi

    1981-01-01

    In order to obtain a radioisotope (RI) tomographic image, there are various, methods, including the RCT method, Time Modulate method, and Multiple Pinhole Coded Aperture (MPCA) method and others. The MPCA method has several advantages. Using the MPCA method, there is no need to move either the detector or the patient, Furthermore, the generally used γ-camera may be used without any alterations. Due to certain problems in reconstructing the tomographic image, the use of the MPCA method in clinical practice is limited to representation of small organs (e.g. heart) using the 7-Pinhole collimator. This research presents an experimental approach to overcome the problems in reconstruction of tomographic images of large organs (organs other than the heart, such as the brain, liver, lung etc.) by introducing a reconstruction algorithm and correction software into the MPCA method. There are 2 main problems in MPCA image reconstruction: (1) Due to the rounding-off procedure, there is both point omission and shifting of point coordinates. (2) The central portion is characterized by high-counts. Both of these problems were solved by incorporating a reconstruction algorithm and a correction function. The resultant corrected tomographic image was processed using a filter derived from subjecting a PSF to a Fourier transform. Thus, it has become possible to obtain a high-quality tomographic image of large organs for clinical use. (author)

  17. Air-supplied pinhole discharge in aqueous solution for the inactivation of Escherichia coli

    Science.gov (United States)

    Suganuma, Ryota; Yasuoka, Koichi

    2018-04-01

    An air-supplied pinhole discharge in aqueous solution has been developed to provide a short-lived and odorless bactericide to replace current conventional disinfectants such as O3, ClO-, HClO, and ClO2. The pinhole discharge that was initiated inside a water bubble generated hydrogen peroxide (H2O2) and nitrous acid (HNO2) simultaneously. The concentrations of H2O2, HNO2, and HNO3 were 16.3, 13.9, and 17.4 mg/L, respectively when flow rates of NaCl solution and air were 72 and 12.5 mL/min, respectively. The pH value of the solution was 3.87, and HO2 radicals were generated from the reaction of H2O2 with HNO2. The efficacy of sterilization of discharge-treated water was evaluated by changing the acetic solutions. A 4-orders-of-magnitude decrease in Escherichia coli survival rate was observed after treatment with a sodium citrate solution of pH 3.2 for 60 s.

  18. Evaluation of commercial nickel-phosphorus coating for ultracold neutron guides using a pinhole bottling method

    Science.gov (United States)

    Pattie, R. W.; Adamek, E. R.; Brenner, T.; Brandt, A.; Broussard, L. J.; Callahan, N. B.; Clayton, S. M.; Cude-Woods, C.; Currie, S. A.; Geltenbort, P.; Ito, T. M.; Lauer, T.; Liu, C. Y.; Majewski, J.; Makela, M.; Masuda, Y.; Morris, C. L.; Ramsey, J. C.; Salvat, D. J.; Saunders, A.; Schroffenegger, J.; Tang, Z.; Wei, W.; Wang, Z.; Watkins, E.; Young, A. R.; Zeck, B. A.

    2017-11-01

    We report on the evaluation of commercial electroless nickel phosphorus (NiP) coatings for ultracold neutron (UCN) transport and storage. The material potential of 50 μm thick NiP coatings on stainless steel and aluminum substrates was measured to be VF = 213(5 . 2) neV using the time-of-flight spectrometer ASTERIX at the Lujan Center. The loss per bounce probability was measured in pinhole bottling experiments carried out at ultracold neutron sources at Los Alamos Neutron Science Center and the Institut Laue-Langevin. For these tests a new guide coupling design was used to minimize gaps between the guide sections. The observed UCN loss in the bottle was interpreted in terms of an energy independent effective loss per bounce, which is the appropriate model when gaps in the system and upscattering are the dominate loss mechanisms, yielding a loss per bounce of 1 . 3(1) × 10-4. We also present a detailed discussion of the pinhole bottling methodology and an energy dependent analysis of the experimental results.

  19. Accelerated median root prior reconstruction for pinhole single-photon emission tomography (SPET)

    Energy Technology Data Exchange (ETDEWEB)

    Sohlberg, Antti [Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, PO Box 1777 FIN-70211, Kuopio (Finland); Ruotsalainen, Ulla [Institute of Signal Processing, DMI, Tampere University of Technology, PO Box 553 FIN-33101, Tampere (Finland); Watabe, Hiroshi [National Cardiovascular Center Research Institute, 5-7-1 Fujisihro-dai, Suita City, Osaka 565-8565 (Japan); Iida, Hidehiro [National Cardiovascular Center Research Institute, 5-7-1 Fujisihro-dai, Suita City, Osaka 565-8565 (Japan); Kuikka, Jyrki T [Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, PO Box 1777 FIN-70211, Kuopio (Finland)

    2003-07-07

    Pinhole collimation can be used to improve spatial resolution in SPET. However, the resolution improvement is achieved at the cost of reduced sensitivity, which leads to projection images with poor statistics. Images reconstructed from these projections using the maximum likelihood expectation maximization (ML-EM) algorithms, which have been used to reduce the artefacts generated by the filtered backprojection (FBP) based reconstruction, suffer from noise/bias trade-off: noise contaminates the images at high iteration numbers, whereas early abortion of the algorithm produces images that are excessively smooth and biased towards the initial estimate of the algorithm. To limit the noise accumulation we propose the use of the pinhole median root prior (PH-MRP) reconstruction algorithm. MRP is a Bayesian reconstruction method that has already been used in PET imaging and shown to possess good noise reduction and edge preservation properties. In this study the PH-MRP algorithm was accelerated with the ordered subsets (OS) procedure and compared to the FBP, OS-EM and conventional Bayesian reconstruction methods in terms of noise reduction, quantitative accuracy, edge preservation and visual quality. The results showed that the accelerated PH-MRP algorithm was very robust. It provided visually pleasing images with lower noise level than the FBP or OS-EM and with smaller bias and sharper edges than the conventional Bayesian methods.

  20. Pinhole bone scan mapping of metabolic profiles in osteoarthritis of the knee: a radiographic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. H.; Kim, H. H.; Chung, Y. A.; Chung, S. K.; Bahk, Y. W. [College of Medicine, The Catholic Univ. of Korea, Seoul (Korea, Republic of)

    1999-07-01

    Osteoarthritis (OA) is mixture of damage to a joint and reaction induced therefrom. Heterogeneity, slow change and no proper means of assessing pathology make it a difficult disease to study. Diagnosis can be made by radiography when OA is established. But subtle metabolic change without radiographic alteration can only be detected by bone scan. Present study was performed to assess metabolic profiles of OA of the knee with various radiographic and preradiographic changes using pinhole bone scan (PBS). PBS and radiography were taken at the same time or a few days apart. We used single-head gamma camera and a 4-mm pinhole collimator. Patients were 9 men and 19 women (30-74 yr with mean being 55). PBS was correlated with radiography in each case. Increased tracer uptake was seen in 111 lesions in 28 knees. Intensity was arbitrarily graded into Grade 0-2. The results were divided into group with radiographic change (n=85; Table) and group without (n=26). Generally, tracer uptake was much intense in the sclerotic and cystic form. In radiographically normal group pathological uptake occurred mostly in subchondral bone (n=17) and some in the femoral condyle (n=9) denoting that subchondral bone is the most vulnerable. PBS is sensitive indicator of metabolic alternations in various disease processes of OA in both radiographically normal and abnormal cases.

  1. Limited angle tomographic breast imaging: A comparison of parallel beam and pinhole collimation

    International Nuclear Information System (INIS)

    Wessell, D.E.; Kadrmas, D.J.; Frey, E.C.

    1996-01-01

    Results from clinical trials have suggested no improvement in lesion detection with parallel hole SPECT scintimammography (SM) with Tc-99m over parallel hole planar SM. In this initial investigation, we have elucidated some of the unique requirements of SPECT SM. With these requirements in mind, we have begun to develop practical data acquisition and reconstruction strategies that can reduce image artifacts and improve image quality. In this paper we investigate limited angle orbits for both parallel hole and pinhole SPECT SM. Singular Value Decomposition (SVD) is used to analyze the artifacts associated with the limited angle orbits. Maximum likelihood expectation maximization (MLEM) reconstructions are then used to examine the effects of attenuation compensation on the quality of the reconstructed image. All simulations are performed using the 3D-MCAT breast phantom. The results of these simulation studies demonstrate that limited angle SPECT SM is feasible, that attenuation correction is needed for accurate reconstructions, and that pinhole SPECT SM may have an advantage over parallel hole SPECT SM in terms of improved image quality and reduced image artifacts

  2. Hybrid Nanomaterial Complexes for Advanced Phage-guided Gene Delivery

    Directory of Open Access Journals (Sweden)

    Teerapong Yata

    2014-01-01

    Full Text Available Developing nanomaterials that are effective, safe, and selective for gene transfer applications is challenging. Bacteriophages (phage, viruses that infect bacteria only, have shown promise for targeted gene transfer applications. Unfortunately, limited progress has been achieved in improving their potential to overcome mammalian cellular barriers. We hypothesized that chemical modification of the bacteriophage capsid could be applied to improve targeted gene delivery by phage vectors into mammalian cells. Here, we introduce a novel hybrid system consisting of two classes of nanomaterial systems, cationic polymers and M13 bacteriophage virus particles genetically engineered to display a tumor-targeting ligand and carry a transgene cassette. We demonstrate that the phage complex with cationic polymers generates positively charged phage and large aggregates that show enhanced cell surface attachment, buffering capacity, and improved transgene expression while retaining cell type specificity. Moreover, phage/polymer complexes carrying a therapeutic gene achieve greater cancer cell killing than phage alone. This new class of hybrid nanomaterial platform can advance targeted gene delivery applications by bacteriophage.

  3. Phage therapy against Enterococcus faecalis in dental root canals

    Directory of Open Access Journals (Sweden)

    Leron Khalifa

    2016-09-01

    Full Text Available Antibiotic resistance is an ever-growing problem faced by all major sectors of health care, including dentistry. Recurrent infections related to multidrug-resistant bacteria such as methicillin-resistant Staphylococcus aureus, carbapenem-resistant Enterobacteriaceae, and vancomycin-resistant enterococci (VRE in hospitals are untreatable and question the effectiveness of notable drugs. Two major reasons for these recurrent infections are acquired antibiotic resistance genes and biofilm formation. None of the traditionally known effective techniques have been able to efficiently resolve these issues. Hence, development of a highly effective antibacterial practice has become inevitable. One example of a hard-to-eradicate pathogen in dentistry is Enterococcus faecalis, which is one of the most common threats observed in recurrent root canal treatment failures, of which the most problematic to treat are its biofilm-forming VRE strains. An effective response against such infections could be the use of bacteriophages (phages. Phage therapy was found to be highly effective against biofilm and multidrug-resistant bacteria and has other advantages like ease of isolation and possibilities for genetic manipulations. The potential of phage therapy in dentistry, in particular against E. faecalis biofilms in root canals, is almost unexplored. Here we review the efforts to develop phage therapy against biofilms. We also focus on the phages isolated against E. faecalis and discuss the possibility of using phages against E. faecalis biofilm in root canals.

  4. How risky are pinholes in gloves? A rational appeal for the integrity of gloves for isolators.

    Science.gov (United States)

    Gessler, Angela; Stärk, Alexandra; Sigwarth, Volker; Moirandat, Claude

    2011-01-01

    Isolators provide a high degree of protection for the product and/or the environment and operators in pharmaceutical production, as well as for analytical and sterility testing. Gloves allow for performing testing and for easy access to the process. Due to their nature-thin plastic, highly flexible-and their risk of puncture or rupture, they are regarded as one of the main potential sources of contamination. Glove integrity testing is therefore a main issue and has been addressed by many regulations such as those imposed by the USP, U.S. Food and Drug Administration, and Pharmaceutical Inspection Convention. This paper presents a short overview of different glove integrity test procedures and their ability to detect leaking gloves. Additionally, extensive microbiological tests have been performed to give more evidence and cross-correlation to physical testing. Most of the physical tests have limitations either in detecting pinholes and/or they are difficult to implement for routine testing. Microbiological tests are only applicable for evaluation and validation purposes, but not for routine testing, because they are time-consuming and do not allow immediate action. Routine visual verification of gloves by trained personnel turns out to be a very reliable technique. Additional microbiological tests supported by microbiological environmental monitoring helped to develop a new concept presented here on how to handle gloves with pinholes. It is proposed not to automatically consider a pinhole in a glove as a breach in isolator integrity, but to consider any action in view of controlling and monitoring the effective bioload on the outside of the gloves. With the combination of semi-automatic physical testing with independent protocol, visual inspection, and control of bioload through microbiological environmental monitoring potential contamination, risks can be minimized and maximum safety maintained. Isolators are enclosure designs to protect critical handling and

  5. Design and evaluation of two multi-pinhole collimators for brain SPECT.

    Science.gov (United States)

    Chen, Ling; Tsui, Benjamin M W; Mok, Greta S P

    2017-10-01

    SPECT is a powerful tool for diagnosing or staging brain diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD) but is limited by its inferior resolution and sensitivity. At the same time, pinhole SPECT provides superior resolution and detection efficiency trade-off as compared to the conventional parallel-hole collimator for imaging small field-of-view (FOV), which fits for the case of brain imaging. In this study, we propose to develop and evaluate two multi-pinhole (MPH) collimator designs to improve the imaging of cerebral blood flow and striatum. We set the target resolutions to be 12 and 8 mm, respectively, and the FOV at 200 mm which is large enough to cover the whole brain. The constraints for system optimization include maximum and minimum detector-to-center-of-FOV (CFOV) distances of 344 and 294 mm, respectively, and minimal radius-of-rotation (ROR) of 135 mm to accommodate patients' shoulder. According to the targeted FOV, resolutions, and constraints, we determined the pinhole number, ROR, focal length, aperture acceptance angle, and aperture diameter which maximized the system sensitivity. We then assessed the imaging performance of the proposed MPH and standard low-energy high-resolution (LEHR) collimators using analytical simulations of a digital NCAT brain phantom with 99m Tc-HMPAO/ 99m Tc-TRODAT-1 distributions; Monte Carlo simulations of a hot-rod phantom; and a Defrise phantom using GATE v6.1. Projections were generated over 360° and reconstructed using the 3D MPH/LEHR OS-EM methods with up to 720 updates. The normalized mean square error (NMSE) was calculated over the cerebral and striatal regions extracted from the reconstructed images for 99m Tc-HMPAO and 99m Tc-TRODAT-1 simulations, respectively, and average normalized standard deviation (NSD) based on 20 noise realizations was assessed on selected uniform 3D regions as the noise index. Visual assessment and image profiles were applied to the results of Monte Carlo

  6. Characterisation of a novel enterobacteria phage, CAjan, isolated from rat faeces.

    Science.gov (United States)

    Carstens, Alexander B; Kot, Witold; Lametsch, Rene; Neve, Horst; Hansen, Lars H

    2016-08-01

    In this study, we describe the isolation and characterisation of the novel enterobacteria phage CAjan. This phage belongs to the order Caudovirales and the family Siphoviridae. The phage possesses a linear, double-stranded DNA genome consisting of 59,670 bp with a G+C content of 44.7 % and 91 predicted open reading frames (ORFs). Putative functions were assigned to 39 of the ORFs (37.4 %). The phage structural genes were furthermore functionally characterised by LC MS/MS. CAjan, together with Escherichia phage Seurat and Escherichia phage slur01, represent a novel and genetically distinct clade of Siphoviridae phages that could be considered to constitute a new phage genus. Despite limited sequence similarity, the phages in this group share a number of other common features, including genome structure and the presence of queuosine biosynthesis genes.

  7. Formation of nano-sized pinholes array in thin Ni film on MgO(100) substrate

    Energy Technology Data Exchange (ETDEWEB)

    Lin Chuan; Naramoto, Hiroshi; Xu Yonghua; Kitazawa, Sin-iti; Narumi, Kazumasa; Sakai, Seiji

    2003-10-22

    We have grown thin Ni films with various thicknesses on polished MgO(100) single crystal substrates in an e-gun evaporation system. The morphology of the as-deposited films was characterized with atomic force microscopy. Pinholes with average diameter of 5-10 nm are found in the film with thickness from 1 to 15 nm, and pinholes array was observed in the film 10 nm thick. The origin of such structure formation is discussed in terms of the elastic strain energy.

  8. Note: Diagnosing femtosecond laser-solid interactions with monochromatic Kα imager and x-ray pinhole camera

    International Nuclear Information System (INIS)

    Lin, X. X.; Li, Y. T.; Liu, F.; Du, F.; Wang, S. J.; Chen, L. M.; Zhang, L.; Zheng, Y.; Liu, X.; Liu, X. L.; Wang, Z. H.; Ma, J. L.; Wei, Z. Y.; Liu, B. C.; Zhang, J.

    2011-01-01

    An x-ray pinhole camera and a monochromatic K α imager are used to measure the interactions of intense femtosecond laser pulses with Cu foil targets. The two diagnostics give different features in the spot size and the laser energy scaling, which are resulted from different physical processes. Under our experimental conditons, the K α emission is mainly excited by the fast electrons transporting inside the cold bulk target. In contrast, the x-ray pinhole signals are dominated by the broadband thermal x-ray emission from the hot plasma at the front target surface.

  9. Phage Therapy Approaches to Reducing Pathogen Persistence and Transmission in Animal Production Environments: Opportunities and Challenges.

    Science.gov (United States)

    Colavecchio, Anna; Goodridge, Lawrence D

    2017-06-01

    The era of genomics has allowed for characterization of phages for use as antimicrobials to treat animal infections with a level of precision never before realized. As more research in phage therapy has been conducted, several advantages of phage therapy have been realized, including the ubiquitous nature, specificity, prevalence in the biosphere, and low inherent toxicity of phages, which makes them a safe and sustainable technology for control of animal diseases. These unique qualities of phages have led to several opportunities with respect to emerging trends in infectious disease treatment. However, the opportunities are tempered by several challenges to the successful implementation of phage therapy, such as the fact that an individual phage can only infect one or a few bacterial strains, meaning that large numbers of different phages will likely be needed to treat infections caused by multiple species of bacteria. In addition, phages are only effective if enough of them can reach the site of bacterial colonization, but clearance by the immune system upon introduction to the animal is a reality that must be overcome. Finally, bacterial resistance to the phages may develop, resulting in treatment failure. Even a successful phage infection and lysis of its host has consequences, because large amounts of endotoxin are released upon lysis of Gram-negative bacteria, which can lead to local and systemic complications. Overcoming these challenges will require careful design and development of phage cocktails, including comprehensive characterization of phage host range and assessment of immunological risks associated with phage treatment.

  10. Electric Field Reconstruction in the Image Plane of a High-Contrast Coronagraph Using a Set of Pinholes Around the Lyot Plane

    Science.gov (United States)

    Giveon, Amir; Kern, Brian; Shaklan, Stuart; Wallace, Kent; Noecker, Charley

    2012-01-01

    The pair-wise estimation has been used now on various testbeds with different coronagraphs with the best contrast results to date. Pinholes estimate has been implemented and ready to be tested in closed loop correction. Pinholes estimate offers an independent method. We hope to improve the calibration process to gain better estimates.

  11. Comparative Omics and Trait Analyses of Marine Pseudoalteromonas Phages Advance the Phage OTU Concept

    Directory of Open Access Journals (Sweden)

    Melissa B. Duhaime

    2017-07-01

    Full Text Available Viruses influence the ecology and evolutionary trajectory of microbial communities. Yet our understanding of their roles in ecosystems is limited by the paucity of model systems available for hypothesis generation and testing. Further, virology is limited by the lack of a broadly accepted conceptual framework to classify viral diversity into evolutionary and ecologically cohesive units. Here, we introduce genomes, structural proteomes, and quantitative host range data for eight Pseudoalteromonas phages isolated from Helgoland (North Sea, Germany and use these data to advance a genome-based viral operational taxonomic unit (OTU definition. These viruses represent five new genera and inform 498 unaffiliated or unannotated protein clusters (PCs from global virus metagenomes. In a comparison of previously sequenced Pseudoalteromonas phage isolates (n = 7 and predicted prophages (n = 31, the eight phages are unique. They share a genus with only one other isolate, Pseudoalteromonas podophage RIO-1 (East Sea, South Korea and two Pseudoalteromonas prophages. Mass-spectrometry of purified viral particles identified 12–20 structural proteins per phage. When combined with 3-D structural predictions, these data led to the functional characterization of five previously unidentified major capsid proteins. Protein functional predictions revealed mechanisms for hijacking host metabolism and resources. Further, they uncovered a hybrid sipho-myovirus that encodes genes for Mu-like infection rarely described in ocean systems. Finally, we used these data to evaluate a recently introduced definition for virus populations that requires members of the same population to have >95% average nucleotide identity across at least 80% of their genes. Using physiological traits and genomics, we proposed a conceptual model for a viral OTU definition that captures evolutionarily cohesive and ecologically distinct units. In this trait-based framework, sensitive hosts are

  12. Evaluation of parathyroid imaging methods with 99mTc-MIBI. The comparison of planar images obtained using a pinhole collimator and a parallel-hole collimator

    International Nuclear Information System (INIS)

    Fujii, Hirofumi; Iwasaki, Ryuichiro; Hashimoto, Jun; Nakamura, Kayoko; Kunieda, Etsuo; Sanmiya, Toshikazu; Kubo, Atsushi; Ogawa, Koichi; Inagaki, Kazutoshi

    1999-01-01

    Parathyroid scintigraphy with 99m Tc-MIBI was performed using two kinds of collimators, namely, a pinhole one and a parallel-hole one, to evaluate which one was more suitable for the detection of hyperfunctioning parathyroid lesions. In the studies using 99m Tc source, the pinhole collimator showed better efficiency and spatial resolution in the distance where the parathyroid scan are actually performed. In the phantom study, the nodular activities modeling parathyroid lesions were visualized better on the images obtained using the pinhole collimator. In clinical studies for 30 patients suspicious of hyperparathyroidism, hyperfunctioning parathyroid nodules were better detected when the pinhole collimator was used. In conclusion, the pinhole collimator was thought to be more suitable for parathyroid scintigraphy with 99m Tc-MIBI than the parallel-hole collimator. (author)

  13. Evaluation of parathyroid imaging methods with {sup 99m}Tc-MIBI. The comparison of planar images obtained using a pinhole collimator and a parallel-hole collimator

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Hirofumi; Iwasaki, Ryuichiro; Hashimoto, Jun; Nakamura, Kayoko; Kunieda, Etsuo; Sanmiya, Toshikazu; Kubo, Atsushi [Keio Univ., Tokyo (Japan). School of Medicine; Ogawa, Koichi; Inagaki, Kazutoshi

    1999-07-01

    Parathyroid scintigraphy with {sup 99m}Tc-MIBI was performed using two kinds of collimators, namely, a pinhole one and a parallel-hole one, to evaluate which one was more suitable for the detection of hyperfunctioning parathyroid lesions. In the studies using {sup 99m}Tc source, the pinhole collimator showed better efficiency and spatial resolution in the distance where the parathyroid scan are actually performed. In the phantom study, the nodular activities modeling parathyroid lesions were visualized better on the images obtained using the pinhole collimator. In clinical studies for 30 patients suspicious of hyperparathyroidism, hyperfunctioning parathyroid nodules were better detected when the pinhole collimator was used. In conclusion, the pinhole collimator was thought to be more suitable for parathyroid scintigraphy with {sup 99m}Tc-MIBI than the parallel-hole collimator. (author)

  14. Factors influencing circadian rhythms in acetaminophen lethality.

    Science.gov (United States)

    Schnell, R C; Bozigian, H P; Davies, M H; Merrick, B A; Park, K S; McMillan, D A

    1984-01-01

    Experiments were conducted to examine the effects of changes in lighting schedules and food consumption on circadian rhythms in acetaminophen lethality and hepatic glutathione levels in male mice. Under a normal lighting schedule (light: 06.00-18.00 h), male mice exhibited a circadian rhythm in acetaminophen lethality (peak: 18.00 h; nadir: 06.00, 10.00 h) and an inverse rhythm in hepatic glutathione concentrations (peak: 06.00, 10.00 h; nadir: 18.00 h). Under a reversed lighting schedule (light: 18.00-06.00 h) the glutathione rhythm was reversed and the rhythm in acetaminophen lethality was altered showing greater sensitivity to the drug. Under continuous light, there was a shift in the acetaminophen lethality and the hepatic glutathione rhythms. Under continuous dark, both rhythms were abolished. Under a normal lighting regimen, hepatic glutathione levels were closely correlated with food consumption; i.e., both were increased during the dark phase and decreased during the light phase. Fasting the mice for 12 h abolished the rhythms in acetaminophen lethality and hepatic glutathione levels; moreover, the lethality was increased and the hepatic glutathione levels were decreased. These experiments show that both lighting schedules and feeding can alter the circadian rhythms in acetaminophen lethality and hepatic glutathione levels in male mice.

  15. [Lethal effect after transmutation of 33P incorporated into bacteriophage S 13 and mechanisms of DNA double helix rupture].

    Science.gov (United States)

    Apelgot, S

    1980-04-01

    The experiments show the lethal effect of the beta decay of 33P incorporated in DNA of bacteriophage S 13. The lethal efficiency is high, 0.72 at 0 degrees C and 0.55 at--197 degrees C. The presence of a radical scavenger like AET has no influence. It was found previously that for such phages with single-stranded DNA, the lethal efficiency of 32P decay is unity, and that the lethal event is a DNA single-strand break, owing to the high energy of the nucleogenic 32S atom. As the recoil energy of the 33S atom is too low to account for such a break, it is suggested that the reorganization of the phosphate molecule into sulphate is able to bring about a DNA single-strand break with an efficiency as high as 0.7, at 0 degrees C. A model for the DNA double-strand-break produced by a transmutation processes is suggested.

  16. Analytical, experimental, and Monte Carlo system response matrix for pinhole SPECT reconstruction

    International Nuclear Information System (INIS)

    Aguiar, Pablo; Pino, Francisco; Silva-Rodríguez, Jesús; Pavía, Javier; Ros, Doménec; Ruibal, Álvaro

    2014-01-01

    Purpose: To assess the performance of two approaches to the system response matrix (SRM) calculation in pinhole single photon emission computed tomography (SPECT) reconstruction. Methods: Evaluation was performed using experimental data from a low magnification pinhole SPECT system that consisted of a rotating flat detector with a monolithic scintillator crystal. The SRM was computed following two approaches, which were based on Monte Carlo simulations (MC-SRM) and analytical techniques in combination with an experimental characterization (AE-SRM). The spatial response of the system, obtained by using the two approaches, was compared with experimental data. The effect of the MC-SRM and AE-SRM approaches on the reconstructed image was assessed in terms of image contrast, signal-to-noise ratio, image quality, and spatial resolution. To this end, acquisitions were carried out using a hot cylinder phantom (consisting of five fillable rods with diameters of 5, 4, 3, 2, and 1 mm and a uniform cylindrical chamber) and a custom-made Derenzo phantom, with center-to-center distances between adjacent rods of 1.5, 2.0, and 3.0 mm. Results: Good agreement was found for the spatial response of the system between measured data and results derived from MC-SRM and AE-SRM. Only minor differences for point sources at distances smaller than the radius of rotation and large incidence angles were found. Assessment of the effect on the reconstructed image showed a similar contrast for both approaches, with values higher than 0.9 for rod diameters greater than 1 mm and higher than 0.8 for rod diameter of 1 mm. The comparison in terms of image quality showed that all rods in the different sections of a custom-made Derenzo phantom could be distinguished. The spatial resolution (FWHM) was 0.7 mm at iteration 100 using both approaches. The SNR was lower for reconstructed images using MC-SRM than for those reconstructed using AE-SRM, indicating that AE-SRM deals better with the

  17. Mechanistic study on black and grey spot growth in OLEDs performed on laser-ablated pinholes in the cathode

    NARCIS (Netherlands)

    Weijer, P. van de; Bouten, P.C.P.; Fledderus, H.; Janssen, R.R.; Winter, S.H.P.M. de; Akkerman, H.B.

    2017-01-01

    Local laser ablation of the cathode of OLEDs has been applied to create a population of pinholes of the same size. This enables the direct comparison at different conditions of black spots and grey spots in the emission of OLEDs as a result of water ingress into the device. We confirmed earlier

  18. Adrenal imaging with 131I-Adosterol (NCL-6-131I) by diverging and pinhole methods, 2

    International Nuclear Information System (INIS)

    Nakajo, Masayuki

    1982-01-01

    The analysis of the adrenal diverging and pinhole images with 131 I-Adosterol was made to establish adrenal imaging patterns, in 43 patients with various adrenal disorders, 4 with adrenal adjacent tumors and one with arrhenoblastoma of the ovary whose images were also included. From this analysis and review of literature, three principles (1. Accumulation in cortical tumors, 2. Relation to endogenous ACTH and 3. Nonaccumulation in noncortical tumors) and several additional factors to make various adrenal imaging patterns with 131 I-iodocholesterols could be induced. The accuracy of locating the adrenal tumor-bearing glands was 97% (28/29) with pinhole images and 70% (21/30) with diverging images in baseline conditions. Various adrenal high/low ratios could not be used as confidential indicators to locate the tumorbearing glands, especially in primary aldosteronism, although the left higher ratios on both views showed high discrepancy between normal and abnormal subjects. The ''Pinhole method'' is recommended as a simple technique of adrenal imaging, because it provides a high-resolution adrenal image which results in a high diagnostic value. A pinhole collimator is available in any institute which has a gamma camera. (author)

  19. Another look at volume self-calibration: calibration and self-calibration within a pinhole model of Scheimpflug cameras

    International Nuclear Information System (INIS)

    Cornic, Philippe; Le Besnerais, Guy; Champagnat, Frédéric; Illoul, Cédric; Cheminet, Adam; Le Sant, Yves; Leclaire, Benjamin

    2016-01-01

    We address calibration and self-calibration of tomographic PIV experiments within a pinhole model of cameras. A complete and explicit pinhole model of a camera equipped with a 2-tilt angles Scheimpflug adapter is presented. It is then used in a calibration procedure based on a freely moving calibration plate. While the resulting calibrations are accurate enough for Tomo-PIV, we confirm, through a simple experiment, that they are not stable in time, and illustrate how the pinhole framework can be used to provide a quantitative evaluation of geometrical drifts in the setup. We propose an original self-calibration method based on global optimization of the extrinsic parameters of the pinhole model. These methods are successfully applied to the tomographic PIV of an air jet experiment. An unexpected by-product of our work is to show that volume self-calibration induces a change in the world frame coordinates. Provided the calibration drift is small, as generally observed in PIV, the bias on the estimated velocity field is negligible but the absolute location cannot be accurately recovered using standard calibration data. (paper)

  20. Multi-dimensional diagnostics of high power ion beams by Arrayed Pinhole Camera System

    International Nuclear Information System (INIS)

    Yasuike, K.; Miyamoto, S.; Shirai, N.; Akiba, T.; Nakai, S.; Imasaki, K.; Yamanaka, C.

    1993-01-01

    The authors developed multi-dimensional beam diagnostics system (with spatially and time resolution). They used newly developed Arrayed Pinhole Camera (APC) for this diagnosis. The APC can get spatial distribution of divergence and flux density. They use two types of particle detectors in this study. The one is CR-39 can get time integrated images. The other one is gated Micro-Channel-Plate (MCP) with CCD camera. It enables time resolving diagnostics. The diagnostics systems have resolution better than 10mrad divergence, 0.5mm spatial resolution on the objects respectively. The time resolving system has 10ns time resolution. The experiments are performed on Reiden-IV and Reiden-SHVS induction linac. The authors get time integrated divergence distributions on Reiden-IV proton beam. They also get time resolved image on Reiden-SHVS

  1. Lasers and laser applications. Imaging implosion dynamics: The x-ray pinhole/streak camera

    International Nuclear Information System (INIS)

    Attwood, D.T.

    1976-01-01

    A Livermore-developed x-ray-sensitive streak camera was combined with a unique x-ray pinhole camera to make dynamic photographs of laser-irradiated fusion target implosions. These photographs show x radiation emitted from the imploding shell during its 100-ps implosion; they are the first continuous observations of an imploding laser-driven fusion capsule. The diagnostic system has a time resolution of 15 ps and a spatial resolution of about 6 μm. Results agree very well with those predicted by our LASNEX calculations, confirming that the essential physics are correctly described in the code and providing further confidence in the soundness of this approach to inertial confinement fusion

  2. Fabricating Pinhole-Free YSZ Sub-Microthin Films by Magnetron Sputtering for Micro-SOFCs

    Directory of Open Access Journals (Sweden)

    T. Hill

    2011-01-01

    Full Text Available Submicron thin yttria stabilized zirconia (YSZ films were prepared on a variety of substrates with different surface morphologies by magnetron sputtering followed by thermal oxidation. Pinholes were observed in the films deposited on nanoporous alumina substrates. Initial dense Y/Zr films developed nanocracks after thermal oxidation on smooth Si wafer substrates. At optimal sputtering and oxidation conditions, smooth and crack/pore-free films were achieved on Si wafer substrates. The thin YSZ films exhibited fully ionic conduction with ionic conductivities, and activation energy corroborated well with the values from commercial YSZ plates. The thin YSZ films can be utilized in Solid Oxide Fuel Cells (SOFCs for intermediate temperature operations.

  3. Transporting Patients with Lethal Contagious Infections

    National Research Council Canada - National Science Library

    Swartz, Colleen

    2002-01-01

    .... The AIT is a unique military medical team capable of worldwide air evacuation and management of a limited number of patients who are potentially exposed to known and unknown lethal communicable...

  4. Advanced Analysis to Distinguish between Physical Decrease and Inactivation of Viable Phages in Aerosol by Quantitating Phage-Specific Particles.

    Science.gov (United States)

    Shimasaki, Noriko; Nojima, Yasuhiro; Sakakibara, Masaya; Kikuno, Ritsuko; Iizuka, Chiori; Okaue, Akira; Okuda, Shunji; Shinohara, Katsuaki

    2018-01-01

     Recent studies have investigated the efficacy of air-cleaning products against pathogens in the air. A standard method to evaluate the reduction in airborne viruses caused by an air cleaner has been established using a safe bacteriophage instead of pathogenic viruses; the reduction in airborne viruses is determined by counting the number of viable airborne phages by culture, after operating the air cleaner. The reduction in the number of viable airborne phages could be because of "physical decrease" or "inactivation". Therefore, to understand the mechanism of reduction correctly, an analysis is required to distinguish between physical decrease and inactivation. The purpose of this study was to design an analysis to distinguish between the physical decrease and inactivation of viable phi-X174 phages in aerosols. We established a suitable polymerase chain reaction (PCR) system by selecting an appropriate primer-probe set for PCR and validating the sensitivity, linearity, and specificity of the primer-probe set to robustly quantify phi-X174-specific airborne particles. Using this quantitative PCR system and culture assay, we performed a behavior analysis of the phage aerosol in a small chamber (1 m 3 ) at different levels of humidity, as humidity is known to affect the number of viable airborne phages. The results revealed that the reduction in the number of viable airborne phages was caused not only by physical decrease but also by inactivation under particular levels of humidity. Our study could provide an advanced analysis to differentiate between the physical decrease and inactivation of viable airborne phages.

  5. Abortive phage-infection and UV-protection markers on ColI plasmids from epidemic strains of Salmonella

    International Nuclear Information System (INIS)

    Barker, R.M.

    1988-01-01

    Cultures of Escherichia coli carrying ColI plasmids received in conjugation from strains of Salmonella typhimurium and S. agona were examined for abortive infection (Abi) of phage BF23 and for enhanced resistance to the lethal action of UV-irradiation (Uvr). The Abi character of stored cultures of E. coli was also compared with the reaction of the same stock culture tested 5 years before. Seven of the eight potential types differentiated by three characters were represented among 160 ColI plasmids: ColIa Abi + Uvr + (3 plasmids), ColIa Abi - Uvr + (1), ColIa Abi - Uvr-> (2), ColIb Abi + Uvr + (85), ColIb Abi + Uvr - (5), ColIb Abi - Uvr + (4), ColIb Abi-? Uvr - (60). Recognition that different plasmid types could be carried by strains of a clone proved useful in the interpretation of the epidemic spread of strains of S. typhimurium of phage type/biotype 141/9f in Scotland and in tracing the ancestry of a recently emerged rhamnose non-fermenting mutant strain of S. agona. (author)

  6. Imaging of intestinal lymphocyte homing by means of pinhole SPECT in a TNBS colitis mouse model

    International Nuclear Information System (INIS)

    Bennink, Roelof J.; Montfrans, Catherine van; Jonge, Wouter J. de; Bruin, Kora de; Deventer, Sander J. van; Velde, Anje A. te

    2004-01-01

    Background and aims: The increasing knowledge of the molecular basis of leukocyte trafficking results in the development of novel anti-inflammatory strategies for inflammatory bowel disease (IBD). For optimal evaluation of therapy efficacy, information about inflammatory activity in bowel segments or lymphocyte recirculation and kinetics in the follow-up of experimental treatment for IBD is needed. The aim of this study was to evaluate a non-invasive scintigraphic technique, able to assess lymphocyte trafficking in a trinitrobenzene sulfonic acid (TNBS) induced mouse colitis model of IBD. Methods: TNBS sensitized and non-sensitized murine total splenocytes were labeled in vitro with 111 In-oxine and injected into either control or TNBS colitis BALB/c mice. Biodistribution and specific radioactive uptake, representing transferred cells, were determined by serial dedicated animal planar scintigraphy and pinhole SPECT of the abdomen 4, 24 and 48h post injection of labeled cells. In addition, the severity of inflammation was. Results: Migration of 111 In labeled splenocytes to the colon increased in time and was maximal at 48h after administration. The highest specific radioactive uptake ratio in the colon after 48h was observed in mice with TNBS colitis that received TNBS sensitized lymphocytes. Histological scoring confirmed the presence of colitis in the TNBS treated groups. Conclusion: Homing of TNBS-sensitized lymphocytes can be assessed in vivo by means of dedicated animal pinhole SPECT. Generally, this technique enables serial measurement of specific cell trafficking with potential of in vivo evaluation of novel anti-inflammatory strategies in inflammatory bowel disease

  7. Phage Therapy in the Era of Synthetic Biology.

    Science.gov (United States)

    Barbu, E Magda; Cady, Kyle C; Hubby, Bolyn

    2016-10-03

    For more than a century, bacteriophage (or phage) research has enabled some of the most important discoveries in biological sciences and has equipped scientists with many of the molecular biology tools that have advanced our understanding of replication, maintenance, and expression of genetic material. Phages have also been recognized and exploited as natural antimicrobial agents and nanovectors for gene therapy, but their potential as therapeutics has not been fully exploited in Western medicine because of challenges such as narrow host range, bacterial resistance, and unique pharmacokinetics. However, increasing concern related to the emergence of bacteria resistant to multiple antibiotics has heightened interest in phage therapy and the development of strategies to overcome hurdles associated with bacteriophage therapeutics. Recent progress in sequencing technologies, DNA manipulation, and synthetic biology allowed scientists to refactor the entire bacterial genome of Mycoplasma mycoides, thereby creating the first synthetic cell. These new strategies for engineering genomes may have the potential to accelerate the construction of designer phage genomes with superior therapeutic potential. Here, we discuss the use of phage as therapeutics, as well as how synthetic biology can create bacteriophage with desirable attributes. Copyright © 2016 Cold Spring Harbor Laboratory Press; all rights reserved.

  8. Exploring the mycobacteriophage metaproteome: phage genomics as an educational platform.

    Directory of Open Access Journals (Sweden)

    Graham F Hatfull

    2006-06-01

    Full Text Available Bacteriophages are the most abundant forms of life in the biosphere and carry genomes characterized by high genetic diversity and mosaic architectures. The complete sequences of 30 mycobacteriophage genomes show them collectively to encode 101 tRNAs, three tmRNAs, and 3,357 proteins belonging to 1,536 "phamilies" of related sequences, and a statistical analysis predicts that these represent approximately 50% of the total number of phamilies in the mycobacteriophage population. These phamilies contain 2.19 proteins on average; more than half (774 of them contain just a single protein sequence. Only six phamilies have representatives in more than half of the 30 genomes, and only three-encoding tape-measure proteins, lysins, and minor tail proteins-are present in all 30 phages, although these phamilies are themselves highly modular, such that no single amino acid sequence element is present in all 30 mycobacteriophage genomes. Of the 1,536 phamilies, only 230 (15% have amino acid sequence similarity to previously reported proteins, reflecting the enormous genetic diversity of the entire phage population. The abundance and diversity of phages, the simplicity of phage isolation, and the relatively small size of phage genomes support bacteriophage isolation and comparative genomic analysis as a highly suitable platform for discovery-based education.

  9. Experiences in therapy for lethal midline granuloma

    International Nuclear Information System (INIS)

    Tosaka, Kaoru; Ishikawa, Takeru

    1982-01-01

    Four cases of the lethal midline granuloma or malignant granuloma of the nose were treated by irradiation and chemotherapy, which are generally prescribed for malignant lymphomas. Clinical, histological and laboratory examination indicated that they were the lethal midline granuloma and clearly differentiated from Wegener's granulomatosis or malignant lymphoma. All of the cases exhibited primary remission. The four cases were observed up to 38, 22, 14, and 10 months since the beginning of the therapy, showing no local or general recurrence. (author)

  10. Identification of the host determinant of two prolate-headed phages infecting lactococcus lactis

    International Nuclear Information System (INIS)

    Stuer-Lauridsen, Birgitte; Janzen, Thomas; Schnabl, Jannie; Johansen, Eric

    2003-01-01

    A gene responsible for host determination was identified in two prolate-headed bacteriophages of the c2 species infecting strains of Lactococcus lactis. The identification of the host determinant gene was based on low DNA sequence homology in a specific open reading frame (ORF) between prolate-headed phages with different host ranges. When a host carrying this ORF from one phage on a plasmid was infected with another phage, we obtained phages with an altered host range at a frequency of 10 -6 to 10 -7 . Sequencing of phage DNA originating from 10 independent single plaques confirmed that a genetic recombination had taken place at different positions between the ORF on the plasmid and the infecting phage. The adsorption of the recombinant phages to their bacterial hosts had also changed to match the phage origin of the ORF. Consequently, it is concluded that this ORF codes for the host range determinant

  11. Understanding the enormous diversity of bacteriophages: the tailed phages that infect the bacterial family Enterobacteriaceae

    Science.gov (United States)

    Grose, Julianne H.; Casjens, Sherwood R.

    2014-01-01

    Bacteriophages are the predominant biological entity on the planet. The recent explosion of sequence information has made estimates of their diversity possible. We describe the genomic comparison of 337 fully sequenced tailed phages isolated on 18 genera and 31 species of bacteria in the Enterobacteriaceae. These phages were largely unambiguously grouped into 56 diverse clusters (32 lytic and 24 temperate) that have syntenic similarity over >50% of the genomes within each cluster, but substantially less sequence similarity between clusters. Most clusters naturally break into sets of more closely related subclusters, 78% of which are correlated with their host genera. The largest groups of related phages are superclusters united by genome synteny to lambda (81 phages) and T7 (51 phages). This study forms a robust framework for understanding diversity and evolutionary relationships of existing tailed phages, for relating newly discovered phages and for determining host/phage relationships. PMID:25240328

  12. Primary Isolation Strain Determines Both Phage Type and Receptors Recognised by Campylobacter jejuni Bacteriophages

    DEFF Research Database (Denmark)

    Sørensen, Martine C. Holst; Gencay, Yilmaz Emre; Birk, Tina

    2015-01-01

    were identified based on host range analysis and genome restriction profiles. Most phages were isolated using C. jejuni strains NCTC12662 and RM1221 and interestingly phage genome size (140 kb vs. 190 kb), host range and morphological appearance correlated with the isolation strain. Thus, according......In this study we isolated novel bacteriophages, infecting the zoonotic bacterium Campylobacter jejuni. These phages may be used in phage therapy of C. jejuni colonized poultry to prevent spreading of the bacteria to meat products causing disease in humans. Many C. jejuni phages have been isolated...... therefore chose seven C. jejuni strains each expressing different CPS structures as indicator strains in a large screening for phages in samples collected from free-range poultry farms. Forty-three phages were isolated using C. jejuni NCTC12658, NCTC12662 and RM1221 as host strains and 20 distinct phages...

  13. Significance of phage-host interactions for biocontrol of Campylobacter jejuni in food

    DEFF Research Database (Denmark)

    Athina, Zampara; Sørensen, Martine Camilla Holst; Elsser-Gravesen, Anne

    2017-01-01

    Poultry meat is the main source of Campylobacter jejuni foodborne disease. Currently, no effective control measures prevent C. jejuni from contaminating poultry meat. However, post-harvest phage treatment is a promising biocontrol strategy that has not yet been explored. Here we identified phages....... A thorough understanding of phage-host interactions is prerequisite to further advance phage application as a post-harvest biocontrol strategy against C. jejuni....

  14. Novel Variants of Streptococcus thermophilus Bacteriophages Are Indicative of Genetic Recombination among Phages from Different Bacterial Species

    DEFF Research Database (Denmark)

    Szymczak, Paula; Janzen, Thomas; Neves, Ana Rute

    2017-01-01

    lactis P335 phages. Phage CHPC1151 was closely related to the atypical S. thermophilus phage 5093, homologous with a nondairy streptococcal prophage. By testing adsorption of the related streptococcal and lactococcal phages to the surface of S. thermophilus and L. lactis strains, we revealed....... thermophilus phages from the Chr. Hansen A/S collection, using PCR specific for the cos- or pac-type phages, as well as for the V2 antireceptor region. Three phages did not produce positive results with the assays. Analysis of phage morphologies indicated that two of these phages, CHPC577 and CHPC926, had...... the possibility of cross-interactions. Our data indicated that the use of S. thermophilus together with L. lactis, extensively applied for dairy fermentations, triggered the recombination between phages infecting different bacterial species. A notable diversity among S. thermophilus phage populations requires...

  15. Influence of environmental factors on phage-bacteria interaction and on the efficacy and infectivity of phage P100

    Directory of Open Access Journals (Sweden)

    Susanne Fister

    2016-07-01

    Full Text Available When using bacteriophages to control food-borne bacteria in food production plants and processed food, it is crucial to consider that environmental conditions influence their stability. These conditions can also affect the physiological state of bacteria and consequently host-virus interaction and the effectiveness of the phage ability to reduce bacteria numbers. In this study we investigated the stability, binding and replication capability of phage P100 and its efficacy to control L. monocytogenes under conditions typically encountered in dairy plants. The influences of SDS, Lutensol AO 7, salt, smear water and different temperatures were investigated. Results indicate that phage P100 is stable and able to bind to the host under most conditions tested. Replication was dependent upon the growth of L. monocytogenes and efficacy was higher when bacterial growth was reduced by certain environmental conditions. In long-term experiments at different temperatures phages were initially able to reduce bacteria up to seven log10 units after two weeks at 4 °C. However, thereafter re-growth and development of phage-resistant L. monocytogenes isolates were encountered.

  16. Changes of the Specific Infectivity of Tracer Phages during Transport in Porous Media.

    Science.gov (United States)

    Ghanem, Nawras; Trost, Manuel; Sánchez Fontanet, Laura; Harms, Hauke; Chatzinotas, Antonis; Wick, Lukas Y

    2018-03-20

    Phages (i.e., viruses infecting bacteria) are considered to be good indicators and tracers for fecal pollution, hydraulic flow, or colloidal transport in the subsurface. They are typically quantified as total virus particles (VLP) or plaque forming units (PFU) of infectious phages. As transport may lead to phage deactivation, VLP quantification can overestimate the number of infectious phages. In contrast, PFU counts may underestimate the transport of total virus particles. Using PFU and tunable resistive pulse sensing-based counting for active and total phages, respectively, we quantified the effect of transport through laboratory percolation columns on the specific infectivity (SI). The SI is defined by the ratio of total VLP to PFU and is a measure for the minimum particle numbers needed to create a single infection. Transport of three marine tracer phages and the coli-phage (T4) was described by colloidal filtration theory. We found that apparent collision efficiencies of active and total phages differed. Depending on the phage properties (e.g., morphology or hydrophobicity), passage through a porous medium led to either an increasing or decreasing SI of effluent phages. Our data suggest that both phage mass recovery and the SI should be considered in quantitative phage tracer experiments.

  17. A fast method for large-scale isolation of phages from hospital ...

    African Journals Online (AJOL)

    This plaque-forming method could be adopted to isolate E. coli phage easily, rapidly and in large quantities. Among the 18 isolated E. coli phages, 10 of them had a broad host range in E. coli and warrant further study. Key words: Escherichia coli phages, large-scale isolation, drug resistance, biological properties.

  18. Genome Sequences of Gordonia Phages BaxterFox, Kita, Nymphadora, and Yeezy

    OpenAIRE

    Pope, Welkin H.; Bandla, Sharanya; Colbert, Alexandra K.; Eichinger, Fiona G.; Gamburg, Michelle B.; Horiates, Stavroula G.; Jamison, Jerrica M.; Julian, Dana R.; Moore, Whitney A.; Murthy, Pranav; Powell, Meghan C.; Smith, Sydney V.; Mezghani, Nadia; Milliken, Katherine A.; Thompson, Paige K.

    2016-01-01

    Gordonia phages BaxterFox, Kita, Nymphadora, and Yeezy are newly characterized phages of Gordonia terrae, isolated from soil samples in Pittsburgh, Pennsylvania. These phages have genome lengths between 50,346 and 53,717?bp, and encode on average 84 predicted proteins. All have G+C content of 66.6%.

  19. Genome Sequences of Gordonia Phages BaxterFox, Kita, Nymphadora, and Yeezy.

    Science.gov (United States)

    Pope, Welkin H; Bandla, Sharanya; Colbert, Alexandra K; Eichinger, Fiona G; Gamburg, Michelle B; Horiates, Stavroula G; Jamison, Jerrica M; Julian, Dana R; Moore, Whitney A; Murthy, Pranav; Powell, Meghan C; Smith, Sydney V; Mezghani, Nadia; Milliken, Katherine A; Thompson, Paige K; Toner, Chelsea L; Ulbrich, Megan C; Furbee, Emily C; Grubb, Sarah R; Warner, Marcie H; Montgomery, Matthew T; Garlena, Rebecca A; Russell, Daniel A; Jacobs-Sera, Deborah; Hatfull, Graham F

    2016-08-11

    Gordonia phages BaxterFox, Kita, Nymphadora, and Yeezy are newly characterized phages of Gordonia terrae, isolated from soil samples in Pittsburgh, Pennsylvania. These phages have genome lengths between 50,346 and 53,717 bp, and encode on average 84 predicted proteins. All have G+C content of 66.6%. Copyright © 2016 Pope et al.

  20. Effect of Bacteriophages on the Growth of Flavobacterium psychrophilum and Development of Phage-Resistant Strains

    DEFF Research Database (Denmark)

    Christiansen, Rói Hammershaimb; Madsen, Lone; Dalsgaard, Inger

    2016-01-01

    The controlling effect of single and multiple phages on the density of Flavobacterium psychrophilum at different initial multiplicity of infection (MOI) was assessed in batch cultures to explore the potential for phage-based treatment of this important fish pathogen. A high initial phage concentr......The controlling effect of single and multiple phages on the density of Flavobacterium psychrophilum at different initial multiplicity of infection (MOI) was assessed in batch cultures to explore the potential for phage-based treatment of this important fish pathogen. A high initial phage...... concentration (MOI = 0.3–4) was crucial for efficient viral lysis, resulting in a 104–105-fold reduction of phage-sensitive cells (both single phages and phage cocktails), which was maintained throughout the incubation (>10 days). Following cell lysis, regrowth of phage-resistant strains was examined...... and resistant strains were isolated for further characterization. The application of a mathematical model allowed simulation of phage-host interactions and resistance development, confirming indications from strain isolations that phage-sensitive strains dominated the regrowing population (>99.8 %) at low MOI...

  1. Restoring logic and data to phage-cures for infectious disease

    Directory of Open Access Journals (Sweden)

    Philip Serwer

    2017-08-01

    Full Text Available Antibiotic therapy for infectious disease is being compromised by emergence of multi-drug-resistant bacterial strains, often called superbugs. A response is to use a cocktail of several bacteria-infecting viruses (bacteriophages or phages to supplement antibiotic therapy. Use of such cocktails is called phage therapy, which has the advantage of response to bacterial resistance that is rapid and not exhaustible. A procedure of well-established success is to make cocktails from stockpiles of stored environmental phages. New phages are added to stockpiles when phage therapy becomes thwarted. The scientific subtext includes optimizing the following aspects: (1 procedure for rapidly detecting, purifying, storing and characterizing phages for optimization of phage cocktails, (2 use of directed evolution in the presence of bacteriostatic compounds to obtain phages that can be most efficiently used for therapy in the presence of these compounds, (3 phage genome sequencing technology and informatics to improve the characterization of phages, and (4 database technology to make optimal use of all relevant information and to rapidly retrieve phages for cocktails that will vary with the infection(s involved. The use of phage stockpiles has an established record, including a recent major human-therapy success by the US Navy. However, I conclude that most research is not along this track and, therefore, is not likely to lead to real world success. I find that a strong case exists for action to rectify this situation.

  2. Complete genome sequences of three Campylobacter jejuni phage-propagating strains

    Science.gov (United States)

    Bacteriophage therapy has the potential to reduce Campylobacter jejuni numbers in livestock, but requires a detailed understanding of phage-host interactions. Some C. jejuni strains are readily infected by certain phages, and are thus designated as phage-propagating strains. Here we report the compl...

  3. Construction and Selection of Affilin® Phage Display Libraries.

    Science.gov (United States)

    Settele, Florian; Zwarg, Madlen; Fiedler, Sebastian; Koscheinz, Daniel; Bosse-Doenecke, Eva

    2018-01-01

    Affilin ® molecules represent a new class of so-called scaffold proteins. The concept of scaffold proteins is to use stable and versatile protein structures which can be endowed with de novo binding properties and specificities by introducing mutations in surface exposed amino acid residues. Complex variations and combinations are generated by genetic methods of randomization resulting in large cDNA libraries. The selection for candidates binding to a desired target can be executed by display methods, especially the very robust and flexible phage display. Here, we describe the construction of ubiquitin based Affilin ® phage display libraries and their use in biopanning experiments for the identification of novel protein ligands.

  4. Is phage therapy acceptable in the immunocompromised host?

    Science.gov (United States)

    Borysowski, Jan; Górski, Andrzej

    2008-09-01

    Over the last decade, bacteriophages (bacterial viruses) have emerged as the major alternative to antibiotics in the treatment of antibiotic-resistant infections. While a considerable body of evidence has accumulated for the efficacy and safety of phage therapy in immunocompetent patients, data remain relatively scarce regarding its use in the immunocompromised host. To our knowledge, the present article is the first to summarize all findings, of both experimental and clinical studies, that may be relevant to the employment of phage therapy in immunocompromised patients. The available data suggest that bacteriophages could also be an efficacious and safe therapeutic modality in such patients.

  5. Radionuclide mass transfer rates from a pinhole in a waste container for an inventory-limited and a constant concentration source

    International Nuclear Information System (INIS)

    LeNeveu, D.M.

    1996-03-01

    Analytical solutions for transient and steady state diffusive mass transfer rates from a pinhole in a waste container are developed for constant concentration and inventory-limited source conditions. Mass transport in three media are considered, inside the pinhole (medium 2), outside the container (medium 3) and inside the container (medium 1). Simple equations are developed for radionuclide mass transfer rates from a pinhole. It is shown that the medium with the largest mass transfer resistance need only be considered to provide a conservative estimate of mass transfer rates. (author) 11 refs., 3 figs

  6. Modeling erosion of unsaturated compacted bentonite by groundwater flow; pinhole erosion test case

    International Nuclear Information System (INIS)

    Laurila, T.; Sane, P.; Olin, M.; Koskinen, K.

    2012-01-01

    Document available in extended abstract form only. Erosion of compacted clay material by water flow is a critical factor affecting the performance of radioactive waste confinement. Our emphasis in this work is the buffer of KBS-3V concept, proposed to be compacted MX-80 bentonite. Unsaturated erosion occurs during the saturation phase of the EBS, and the main quantity of interest is the total buffer mass carried away by a groundwater flow that induces erosion by forming piping channels near the buffer/rock interface. The purpose of this work is to provide modeling tools to support erosion experiments. Role of modeling is first to interpret experimental observations in terms of processes, and to estimate robustness of experimental results. Secondly, we seek to scale up results from the laboratory scale, particularly to time scales longer than those experimentally accessible. We have performed modeling and data analysis pertaining to tests of unsaturated clay erosion. Pinhole experiments were used to study this erosion case. The main differences to well-understood pinhole erosion tests are that the material is strongly swelling and that the water flow is not determined by the pressure head but by the total flux. Groundwater flow in the buffer is determined by the flux because pressure losses occur overwhelmingly in the surrounding rock, not in the piping channel. We formulate a simple model that links an effective solid diffusivity -based swelling model to erosion by flow on the solid/liquid interface. The swelling model is similar in concept to that developed at KTH, but simpler. Erosion in the model is caused by laminar flow in the pinhole, and happens in a narrow region at the solid/liquid interface where velocity and solid volume fraction overlap. The erosion model can be mapped to erosion by wall shear, and can thus be considered as extension of that classic erosion model. The main quantity defining the behavior of clay erosion in the model is the ratio of

  7. Marine phages as excellent tracers for reactive colloidal transport in porous media

    Science.gov (United States)

    Ghanem, Nawras; Chatzinotas, Antonis; Harms, Hauke; Wick, Lukas Y.

    2016-04-01

    Question: Here we evaluate marine phages as specific markers of hydrological flow and reactive transport of colloidal particles in the Earth's critical zone (CZ). Marine phages and their bacterial hosts are naturally absent in the CZ, and can be detected with extremely high sensitivity. In the framework of the DFG Collaborative Research Center AquaDiva, we asked the following questions: (1) Are marine phages useful specific markers of hydrological flow and reactive transport in porous media? and (2) Which phage properties are relevant drivers for the transport of marine phages in porous media? Methods: Seven marine phages from different families (as well two commonly used terrestrial phages) were selected based on their morphology, size and physico-chemical surface properties (surface charge and hydrophobicity). Phage properties were assessed by electron microscopy, dynamic light scattering and water contact angle analysis (CA). Sand-filled laboratory percolation columns were used to study transport. The breakthrough curves of the phages were analyzed using the clean bed filtration theory and the XDLVO theory of colloid stability, respectively. Phages were quantified by a modified high- throughput plaque assay and a culture-independent particle counting method approach. Results: Our data show that most marine tested phages exhibited highly variable transport rates and deposition efficiency, yet generally high colloidal stability and viability. We find that size, morphology and hydrophobicity are key factors shaping the transport efficiency of phages. Differing deposition efficiencies of the phages were also supported by calculated XDLVO interaction energy profile. Conclusion: Marine phages have a high potential for the use as sensitive tracers in terrestrial habitats with their surface properties playing a crucial role for their transport. Marine phages however, exhibit differences in their deposition efficiency depending on their morphology, hydrophobicity and

  8. Lethality Index 2008-2014: Less shootings, same lethality, more opacity

    Directory of Open Access Journals (Sweden)

    Carlos Silva Forné

    2017-11-01

    Full Text Available This article evaluates the use of lethal force by Mexican federal security forces during shootings with presumed members of organized crime from 2008-2014. The authors use official data and press reports on deaths and wounded in shootings to construct indicators such as the number of dead civilians over the number of dead officials from the federal security forces and the number of dead civilians over the number of wounded civilians. In a context where certain factors that contribute to an excessive use of force become more common, the results of the study show a growing use of lethal force. This raises questions over the possible excessive use of lethal force as a normal or systematic practice. The study also shows a growing context of opacity in the information available to evaluate the use of lethal force and the general lack of a legal framework to regulate the use of lethal force in Mexico.

  9. Analytical, experimental, and Monte Carlo system response matrix for pinhole SPECT reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Pablo, E-mail: pablo.aguiar.fernandez@sergas.es [Fundación Ramón Domínguez, Medicina Nuclear, CHUS, Spain and Grupo de Imaxe Molecular, IDIS, Santiago de Compostela 15706 (Spain); Pino, Francisco [Unitat de Biofísica, Facultat de Medicina, Universitat de Barcelona, Spain and Servei de Física Médica i Protecció Radiológica, Institut Catalá d' Oncologia, Barcelona 08036 (Spain); Silva-Rodríguez, Jesús [Fundación Ramón Domínguez, Medicina Nuclear, CHUS, Santiago de Compostela 15706 (Spain); Pavía, Javier [Servei de Medicina Nuclear, Hospital Clínic, Barcelona (Spain); Institut d' Investigacions Biomèdiques August Pí i Sunyer (IDIBAPS) (Spain); CIBER en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona 08036 (Spain); Ros, Doménec [Unitat de Biofísica, Facultat de Medicina, Casanova 143 (Spain); Institut d' Investigacions Biomèdiques August Pí i Sunyer (IDIBAPS) (Spain); CIBER en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona 08036 (Spain); Ruibal, Álvaro [Servicio Medicina Nuclear, CHUS (Spain); Grupo de Imaxe Molecular, Facultade de Medicina (USC), IDIS, Santiago de Compostela 15706 (Spain); Fundación Tejerina, Madrid (Spain); and others

    2014-03-15

    Purpose: To assess the performance of two approaches to the system response matrix (SRM) calculation in pinhole single photon emission computed tomography (SPECT) reconstruction. Methods: Evaluation was performed using experimental data from a low magnification pinhole SPECT system that consisted of a rotating flat detector with a monolithic scintillator crystal. The SRM was computed following two approaches, which were based on Monte Carlo simulations (MC-SRM) and analytical techniques in combination with an experimental characterization (AE-SRM). The spatial response of the system, obtained by using the two approaches, was compared with experimental data. The effect of the MC-SRM and AE-SRM approaches on the reconstructed image was assessed in terms of image contrast, signal-to-noise ratio, image quality, and spatial resolution. To this end, acquisitions were carried out using a hot cylinder phantom (consisting of five fillable rods with diameters of 5, 4, 3, 2, and 1 mm and a uniform cylindrical chamber) and a custom-made Derenzo phantom, with center-to-center distances between adjacent rods of 1.5, 2.0, and 3.0 mm. Results: Good agreement was found for the spatial response of the system between measured data and results derived from MC-SRM and AE-SRM. Only minor differences for point sources at distances smaller than the radius of rotation and large incidence angles were found. Assessment of the effect on the reconstructed image showed a similar contrast for both approaches, with values higher than 0.9 for rod diameters greater than 1 mm and higher than 0.8 for rod diameter of 1 mm. The comparison in terms of image quality showed that all rods in the different sections of a custom-made Derenzo phantom could be distinguished. The spatial resolution (FWHM) was 0.7 mm at iteration 100 using both approaches. The SNR was lower for reconstructed images using MC-SRM than for those reconstructed using AE-SRM, indicating that AE-SRM deals better with the

  10. TfR Binding Peptide Screened by Phage Display Technology ...

    African Journals Online (AJOL)

    Purpose: To screen an hTfR affinity peptide and investigate its activity in vitro. Methods: hTfR ... Keywords: Peptide, hTfR, Transferrin receptor, Phage display technology, Enhanced green ..... mediated uptake of peptides that bind the human.

  11. Lambda phage genetic switch as a system with critical behaviour

    Czech Academy of Sciences Publication Activity Database

    Vohradský, Jiří

    2017-01-01

    Roč. 431, OCT 27 2017 (2017), s. 32-38 ISSN 0022-5193 R&D Projects: GA MŠk(CZ) LM2015055 Institutional support: RVO:61388971 Keywords : Critical behaviour * Phage lambda * Genetic networks Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 2.113, year: 2016

  12. Clear Plaque Mutants of Lactococcal Phage TP901-1

    DEFF Research Database (Denmark)

    Kot, Witold; Kilstrup, Mogens; Vogensen, Finn K.

    2016-01-01

    We report a method for obtaining turbid plaques of the lactococcal bacteriophage TP901-1 and its derivative TP901-BC1034. We have further used the method to isolate clear plaque mutants of this phage. Analysis of 8 such mutants that were unable to lysogenize the host included whole genome...

  13. Genome Sequence of Gordonia Phage BetterKatz

    Science.gov (United States)

    Berryman, Emily N.; Forrest, Kaitlyn M.; McHale, Lilliana; Wertz, Anthony T.; Zhuang, Zenas; Kasturiarachi, Naomi S.; Pressimone, Catherine A.; Schiebel, Johnathon G.; Furbee, Emily C.; Grubb, Sarah R.; Warner, Marcie H.; Montgomery, Matthew T.; Garlena, Rebecca A.; Russell, Daniel A.; Jacobs-Sera, Deborah; Hatfull, Graham F.

    2016-01-01

    BetterKatz is a bacteriophage isolated from a soil sample collected in Pittsburgh, Pennsylvania using the host Gordonia terrae 3612. BetterKatz’s genome is 50,636 bp long and contains 75 predicted protein-coding genes, 35 of which have been assigned putative functions. BetterKatz is not closely related to other sequenced Gordonia phages. PMID:27516497

  14. Phage Genetic Engineering Using CRISPR–Cas Systems

    Directory of Open Access Journals (Sweden)

    Asma Hatoum-Aslan

    2018-06-01

    Full Text Available Since their discovery over a decade ago, the class of prokaryotic immune systems known as CRISPR–Cas have afforded a suite of genetic tools that have revolutionized research in model organisms spanning all domains of life. CRISPR-mediated tools have also emerged for the natural targets of CRISPR–Cas immunity, the viruses that specifically infect bacteria, or phages. Despite their status as the most abundant biological entities on the planet, the majority of phage genes have unassigned functions. This reality underscores the need for robust genetic tools to study them. Recent reports have demonstrated that CRISPR–Cas systems, specifically the three major types (I, II, and III, can be harnessed to genetically engineer phages that infect diverse hosts. Here, the mechanisms of each of these systems, specific strategies used, and phage editing efficacies will be reviewed. Due to the relatively wide distribution of CRISPR–Cas systems across bacteria and archaea, it is anticipated that these immune systems will provide generally applicable tools that will advance the mechanistic understanding of prokaryotic viruses and accelerate the development of novel technologies based on these ubiquitous organisms.

  15. Strain diversity and phage resistance in complex dairy starter cultures

    NARCIS (Netherlands)

    Spus, M.; Alexeeva, S.V.; Wolkers-Rooijackers, J.C.M.; Zwietering, M.H.; Abee, T.; Smid, E.J.

    2015-01-01

    The compositional stability of the complex Gouda cheese starter culture Ur is thought to be influenced by diversity in phage resistance of highly related strains that co-exist together with bacteriophages. To analyze the role of bacteriophages in maintaining culture diversity at the level of genetic

  16. HostPhinder: A Phage Host Prediction Tool

    DEFF Research Database (Denmark)

    Villarroel, Julia; Kleinheinz, Kortine Annina; Jurtz, Vanessa Isabell

    2016-01-01

    The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within...... bacterial hosts. HostPhinder is available as an interactive web service [1] and as a stand alone download from the Docker registry [2]....

  17. A highly specific phage defense system is a conserved feature of the Vibrio cholerae mobilome.

    Directory of Open Access Journals (Sweden)

    Brendan J O'Hara

    2017-06-01

    Full Text Available Vibrio cholerae-specific bacteriophages are common features of the microbial community during cholera infection in humans. Phages impose strong selective pressure that favors the expansion of phage-resistant strains over their vulnerable counterparts. The mechanisms allowing virulent V. cholerae strains to defend against the ubiquitous threat of predatory phages have not been established. Here, we show that V. cholerae PLEs (phage-inducible chromosomal island-like elements are widespread genomic islands dedicated to phage defense. Analysis of V. cholerae isolates spanning a 60-year collection period identified five unique PLEs. Remarkably, we found that all PLEs (regardless of geographic or temporal origin respond to infection by a myovirus called ICP1, the most prominent V. cholerae phage found in cholera patient stool samples from Bangladesh. We found that PLE activity reduces phage genome replication and accelerates cell lysis following ICP1 infection, killing infected host cells and preventing the production of progeny phage. PLEs are mobilized by ICP1 infection and can spread to neighboring cells such that protection from phage predation can be horizontally acquired. Our results reveal that PLEs are a persistent feature of the V. cholerae mobilome that are adapted to providing protection from a single predatory phage and advance our understanding of how phages influence pathogen evolution.

  18. A highly specific phage defense system is a conserved feature of the Vibrio cholerae mobilome.

    Science.gov (United States)

    O'Hara, Brendan J; Barth, Zachary K; McKitterick, Amelia C; Seed, Kimberley D

    2017-06-01

    Vibrio cholerae-specific bacteriophages are common features of the microbial community during cholera infection in humans. Phages impose strong selective pressure that favors the expansion of phage-resistant strains over their vulnerable counterparts. The mechanisms allowing virulent V. cholerae strains to defend against the ubiquitous threat of predatory phages have not been established. Here, we show that V. cholerae PLEs (phage-inducible chromosomal island-like elements) are widespread genomic islands dedicated to phage defense. Analysis of V. cholerae isolates spanning a 60-year collection period identified five unique PLEs. Remarkably, we found that all PLEs (regardless of geographic or temporal origin) respond to infection by a myovirus called ICP1, the most prominent V. cholerae phage found in cholera patient stool samples from Bangladesh. We found that PLE activity reduces phage genome replication and accelerates cell lysis following ICP1 infection, killing infected host cells and preventing the production of progeny phage. PLEs are mobilized by ICP1 infection and can spread to neighboring cells such that protection from phage predation can be horizontally acquired. Our results reveal that PLEs are a persistent feature of the V. cholerae mobilome that are adapted to providing protection from a single predatory phage and advance our understanding of how phages influence pathogen evolution.

  19. Diversity of phage infection types and associated terminology: the problem with 'Lytic or lysogenic'.

    Science.gov (United States)

    Hobbs, Zack; Abedon, Stephen T

    2016-04-01

    Bacteriophages, or phages, are viruses of members of domain Bacteria. These viruses play numerous roles in shaping the diversity of microbial communities, with impact differing depending on what infection strategies specific phages employ. From an applied perspective, these especially are communities containing undesired or pathogenic bacteria that can be modified through phage-mediated bacterial biocontrol, that is, through phage therapy. Here we seek to categorize phages in terms of their infection strategies as well as review or suggest more descriptive, accurate or distinguishing terminology. Categories can be differentiated in terms of (1) whether or not virion release occurs (productive infections versus lysogeny, pseudolysogeny and/or the phage carrier state), (2) the means of virion release (lytic versus chronic release) and (3) the degree to which phages are genetically equipped to display lysogenic cycles (temperate versus non-temperate phages). We address in particular the use or overuse of what can be a somewhat equivocal phrase, 'Lytic or lysogenic', especially when employed as a means of distinguishing among phages types. We suggest that the implied dichotomy is inconsistent with both modern as well as historical understanding of phage biology. We consider, therefore, less ambiguous terminology for distinguishing between 'Lytic' versus 'Lysogenic' phage types. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Reconstruction of quasimonochromatic images for multispectral x-ray imaging with a pinhole array and a flat Bragg mirror

    International Nuclear Information System (INIS)

    Izumi, N.; Barbee, T. W.; Koch, J. A.; Mancini, R. C.; Welser, L. A.

    2006-01-01

    We have developed a software package for reconstruction of quasimonochromatic images from a multiple monochromatic x-ray imager for inertial confinement fusion implosions. The instrument consists of a pinhole array, a multilayer Bragg mirror, and an image detector. The pinhole array projects hundreds of images onto the detector after reflection off the multilayer Bragg mirror, which introduces spectral dispersion along the reflection axis. The quasimonochromatic images of line emissions and continuum emissions can be used for measurement of temperature and density maps of implosion plasmas. In this article, we describe a computer-aided processing technique for systematic reconstruction of quasimonochromatic images from raw data. This technique provides flexible spectral bandwidth selection and allows systematic subtraction of continuum emission from line emission images

  1. Tomographic and analog 3-D simulations using NORA. [Non-Overlapping Redundant Image Array formed by multiple pinholes

    Science.gov (United States)

    Yin, L. I.; Trombka, J. I.; Bielefeld, M. J.; Seltzer, S. M.

    1984-01-01

    The results of two computer simulations demonstrate the feasibility of using the nonoverlapping redundant array (NORA) to form three-dimensional images of objects with X-rays. Pinholes admit the X-rays to nonoverlapping points on a detector. The object is reconstructed in the analog mode by optical correlation and in the digital mode by tomographic computations. Trials were run with a stick-figure pyramid and extended objects with out-of-focus backgrounds. Substitution of spherical optical lenses for the pinholes increased the light transmission sufficiently that objects could be easily viewed in a dark room. Out-of-focus aberrations in tomographic reconstruction could be eliminated using Chang's (1976) algorithm.

  2. Single order soft X-ray diffraction with quasi-random radius pinhole array spectroscopic photon sieves

    International Nuclear Information System (INIS)

    Zhang Qiang-Qiang; Wei Lai; Yang Zu-Hua; Qian Feng; Fan Quan-Ping; Zhang Bo; Gu Yu-Qiu; Cao Lei-Feng

    2014-01-01

    A novel single order diffraction grating in the soft X-ray region, called quasi-random radius pinhole array spectroscopic photon sieves (QRSPS), is proposed in this paper. This new grating is composed of pinholes on a substrate, whose radii are quasi-random, while their centers are regular. Analysis proves that its transmittance function across the grating bar is similar to that of sinusoidal transmission gratings. Simulation results show that the QRSPS can suppress higher-order diffraction effectively. And the QRSPS would still retain its characteristic of single order diffraction when we take the effect of X-ray penetration into account. These properties indicate that the QRSPS can be used in the soft X-ray spectra measurement. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  3. Morphobiochemical diagnosis of acute trabecular microfractures using gamma correction Tc-99m HDP pinhole bone scan with histopathological verification.

    Science.gov (United States)

    Bahk, Yong-Whee; Hwang, Seok-Ha; Lee, U-Young; Chung, Yong-An; Jung, Joo-Young; Jeong, Hyeonseok S

    2017-11-01

    We prospectively performed gamma correction pinhole bone scan (GCPBS) and histopathologic verification study to make simultaneous morphobiochemical diagnosis of trabecular microfractures (TMF) occurred in the femoral head as a part of femoral neck fracture.Materials consisted of surgical specimens of the femoral head in 6 consecutive patients. The specimens were imaged using Tc-99m hydroxymethylene diphosphonate (HDP) pinhole scan and processed by the gamma correction. After cleansing with 10% formalin solution, injured specimen surface was observed using a surgical microscope to record TMF. Morphological findings shown in the photograph, naive pinhole bone scan, GCPBS, and hematoxylin-eosin (H&E) stain of the specimen were reciprocally correlated for histological verification and the usefulness of suppression and enhancement of Tc-99m HDP uptake was biochemically investigated in TMF and edema and hemorrhage using gamma correction.On the one hand, GCPBS was able to depict the calcifying calluses in TMF with enhanced Tc-99m HDP uptake. They were pinpointed, speckled, round, ovoid, rod-like, geographic, and crushed in shape. The smallest callus measured was 0.23 mm in this series. On the other hand, GCPBS biochemically was able to discern the calluses with enhanced high Tc-99m HDP uptake from the normal and edema dipped and hemorrhage irritated trabeculae with washed out uptake.Morphobiochemically, GCPBS can clearly depict microfractures in the femoral head produced by femoral neck fracture. It discerns the microcalluses with enhanced Tc-99m HDP uptake from the intact and edema dipped and hemorrhage irritated trabeculae with suppressed washed out Tc-99m HDP uptake. Both conventional pinhole bone scan and gamma correction are useful imaging means to specifically diagnose the microcalluses naturally formed in TMF.

  4. The feasibility study on 3-dimensional fluorescent x-ray computed tomography using the pinhole effect for biomedical applications.

    Science.gov (United States)

    Sunaguchi, Naoki; Yuasa, Tetsuya; Hyodo, Kazuyuki; Zeniya, Tsutomu

    2013-01-01

    We propose a 3-dimensional fluorescent x-ray computed tomography (CT) pinhole collimator, aimed at providing molecular imaging with quantifiable measures and sub-millimeter spatial resolution. In this study, we demonstrate the feasibility of this concept and investigate imaging properties such as spatial resolution, contrast resolution and quantifiable measures, by imaging physical phantoms using a preliminary imaging system developed with monochromatic synchrotron x rays constructed at the BLNE-7A experimental line at KEK, Japan.

  5. Characterizing RecA-independent induction of Shiga toxin2-encoding phages by EDTA treatment.

    Directory of Open Access Journals (Sweden)

    Lejla Imamovic

    Full Text Available BACKGROUND: The bacteriophage life cycle has an important role in Shiga toxin (Stx expression. The induction of Shiga toxin-encoding phages (Stx phages increases toxin production as a result of replication of the phage genome, and phage lysis of the host cell also provides a means of Stx toxin to exit the cell. Previous studies suggested that prophage induction might also occur in the absence of SOS response, independently of RecA. METHODOLOGY/PRINCIPAL FINDINGS: The influence of EDTA on RecA-independent Stx2 phage induction was assessed, in laboratory lysogens and in EHEC strains carrying Stx2 phages in their genome, by Real-Time PCR. RecA-independent mechanisms described for phage λ induction (RcsA and DsrA were not involved in Stx2 phage induction. In addition, mutations in the pathway for the stress response of the bacterial envelope to EDTA did not contribute to Stx2 phage induction. The effect of EDTA on Stx phage induction is due to its chelating properties, which was also confirmed by the use of citrate, another chelating agent. Our results indicate that EDTA affects Stx2 phage induction by disruption of the bacterial outer membrane due to chelation of Mg(2+. In all the conditions evaluated, the pH value had a decisive role in Stx2 phage induction. CONCLUSIONS/SIGNIFICANCE: Chelating agents, such as EDTA and citrate, induce Stx phages, which raises concerns due to their frequent use in food and pharmaceutical products. This study contributes to our understanding of the phenomenon of induction and release of Stx phages as an important factor in the pathogenicity of Shiga toxin-producing Escherichia coli (STEC and in the emergence of new pathogenic strains.

  6. Obtaining absolute spatial flux measurements with a time-resolved pinhole camera

    International Nuclear Information System (INIS)

    Baker, K.L.; Porter, J.L.; Ruggles, L.E.; Fehl, D.L.; Chandler, G.A.; Vargas, M.; Mix, L.P.; Simpson, W.W.; Deeney, C.; Chrien, R.E.; Idzorek, G.C.

    1999-01-01

    A technique is described to determine the spatial x-ray flux emitted from a hohlraum wall and subsequently transmitted through a diagnostic hole. This technique uses x-ray diodes, bolometers, and a time-resolved pinhole camera to determine the spatial flux of x rays emitted through a hohlraum close-quote s diagnostic hole. The primary motivation for this analysis was the relatively long duration, nearly 100 ns, of the x-ray drive present in z-pinch driven hohlraums. This radiation causes plasma to ablate from the hohlraum walls surrounding the diagnostic hole and results in a partial obscuration that reduces the effective area over which diagnostics view the radiation. The effective change in area leads to an underestimation of the wall temperature when nonimaging diagnostics such as x-ray diodes and bolometers are used to determine power and later to infer a wall temperature. An analysis similar to the one described below is then necessary to understand the radiation environment present in x-ray driven hohlraums when these diagnostics are used and hole closure is important. copyright 1999 American Institute of Physics

  7. GATE simulation of a new design of pinhole SPECT system for small animal brain imaging

    International Nuclear Information System (INIS)

    Ozsahin, D. Uzun; Bläckberg, L.; Fakhri, G. El; Sabet, H.

    2017-01-01

    Small animal SPECT imaging has gained an increased interest over the past decade since it is an excellent tool for developing new drugs and tracers. Therefore, there is a huge effort on the development of cost-effective SPECT detectors with high capabilities. The aim of this study is to simulate the performance characteristics of new designs for a cost effective, stationary SPECT system dedicated to small animal imaging with a focus on mice brain. The conceptual design of this SPECT system platform, Stationary Small Animal SSA-SPECT, is to use many pixelated CsI:TI detector modules with 0.4 mm × 0.4 mm pixels in order to achieve excellent intrinsic detector resolution where each module is backed by a single pinhole collimator with 0.3 mm hole diameter. In this work, we present the simulation results of four variations of the SSA-SPECT platform where the number of detector modules and FOV size is varied while keeping the detector size and collimator hole size constant. Using the NEMA NU-4 protocol, we performed spatial resolution, sensitivity, image quality simulations followed by a Derenzo-like phantom evaluation. The results suggest that all four SSA-SPECT systems can provide better than 0.063% system sensitivity and < 1.5 mm FWHM spatial resolution without resolution recovery or other correction techniques. Specifically, SSA-SPECT-1 showed a system sensitivity of 0.09% in combination with 1.1 mm FWHM spatial resolution.

  8. Wireless Synchronization of a Multi-Pinhole Small Animal SPECT Collimation Device With a Clinical Scanner

    Science.gov (United States)

    DiFilippo, Frank P.; Patel, Sagar

    2009-06-01

    A multi-pinhole collimation device for small animal single photon emission computed tomography (SPECT) uses the gamma camera detectors of a standard clinical SPECT scanner. The collimator and animal bed move independently of the detectors, and therefore their motions must be synchronized. One approach is manual triggering of the SPECT acquisition simultaneously with a programmed motion sequence for the device. However, some data blurring and loss of image quality result, and true electronic synchronization is preferred. An off-the-shelf digital gyroscope with integrated Bluetooth interface provides a wireless solution to device synchronization. The sensor attaches to the SPECT gantry and reports its rotational speed to a notebook computer controlling the device. Software processes the rotation data in real-time, averaging the signal and issuing triggers while compensating for baseline drift. Motion commands are sent to the collimation device with minimal delay, within approximately 0.5 second of the start of SPECT gantry rotation. Test scans of a point source demonstrate an increase in true counts and a reduction in background counts compared to manual synchronization. The wireless rotation sensor provides robust synchronization of the collimation device with the clinical SPECT scanner and enhances image quality.

  9. Modeling and characterization of a SPECT system with pinhole collimation for the imaging of small animals

    International Nuclear Information System (INIS)

    Auer, Benjamin

    2017-01-01

    My thesis work focuses on the development of several quantitative reconstruction methods dedicated to small animal Single Photon Emission Computed Tomography (SPECT). The latter is based on modeling the acquisition process of the 4-heads pinhole SPECT system available at Institut Pluridisciplinaire Hubert Curien (IPHC) and fully integrated to the AMISSA platform using Monte Carlo simulations. The system matrix approach, combined with the OS-EM iterative reconstruction algorithm, enabled to characterize the system performances and to compare it to the state of the art. Sensitivity of about 0,027% in the center of the field of view associated to a tomographic spatial resolution of 0, 875 ± 0, 025 mm were obtained. The major drawbacks of Monte Carlo methods led us to develop an efficient and simplified modeling of the physical effects occurring in the subject. My approach based on a system matrix decomposition, associated to a scatter pre-calculated database method, demonstrated an acceptable time for a daily imaging subject follow-up (∼ 1 h), leading to a personalized imaging reconstruction (article accepted). The inherent approximations of the scatter pre-calculated approach (first order scattering modeling and segmented emission) have a moderate impact on the recovery coefficients results, nevertheless a correction of about 10% was achieved. (author) [fr

  10. Estimation of signal intensity for online measurement X-ray pinhole camera

    International Nuclear Information System (INIS)

    Dong Jianjun; Liu Shenye; Yang Guohong; Yu Yanning

    2009-01-01

    The signal intensity was estimated for on-line measurement X-ray pinhole camera with CCD as measurement equipment. The X-ray signal intensity counts after the attenuation of thickness-varied Be filters and different material flat mirrors respectively were estimated using the energy spectrum of certain laser prototype and the quantum efficiency curve of PI-SX1300 CCD camera. The calculated results indicate that Be filters no thicker than 200 μm can only reduce signal intensity by one order of magnitude, and so can Au flat mirror with 3 degree incident angle, Ni, C and Si flat mirrors with 5 degree incident angle,but the signal intensity counts for both attenuation methods are beyond the saturation counts of the CCD camera. We also calculated the attenuation of signal intensity for different thickness Be filters combined with flat mirrors, indicates that the combination of Be filters with the thickness between 20 and 40 μm and Au flat mirror with 3 degree incident angle or Ni flat mirror with 5 degree incident angle is a good choice for the attenuation of signal intensity. (authors)

  11. The performance of a hybrid analytical-Monte Carlo system response matrix in pinhole SPECT reconstruction

    International Nuclear Information System (INIS)

    El Bitar, Z; Pino, F; Candela, C; Ros, D; Pavía, J; Rannou, F R; Ruibal, A; Aguiar, P

    2014-01-01

    It is well-known that in pinhole SPECT (single-photon-emission computed tomography), iterative reconstruction methods including accurate estimations of the system response matrix can lead to submillimeter spatial resolution. There are two different methods for obtaining the system response matrix: those that model the system analytically using an approach including an experimental characterization of the detector response, and those that make use of Monte Carlo simulations. Methods based on analytical approaches are faster and handle the statistical noise better than those based on Monte Carlo simulations, but they require tedious experimental measurements of the detector response. One suggested approach for avoiding an experimental characterization, circumventing the problem of statistical noise introduced by Monte Carlo simulations, is to perform an analytical computation of the system response matrix combined with a Monte Carlo characterization of the detector response. Our findings showed that this approach can achieve high spatial resolution similar to that obtained when the system response matrix computation includes an experimental characterization. Furthermore, we have shown that using simulated detector responses has the advantage of yielding a precise estimate of the shift between the point of entry of the photon beam into the detector and the point of interaction inside the detector. Considering this, it was possible to slightly improve the spatial resolution in the edge of the field of view. (paper)

  12. Novel energy resolving x-ray pinhole camera on Alcator C-Moda)

    Science.gov (United States)

    Pablant, N. A.; Delgado-Aparicio, L.; Bitter, M.; Brandstetter, S.; Eikenberry, E.; Ellis, R.; Hill, K. W.; Hofer, P.; Schneebeli, M.

    2012-10-01

    A new energy resolving x-ray pinhole camera has been recently installed on Alcator C-Mod. This diagnostic is capable of 1D or 2D imaging with a spatial resolution of ≈1 cm, an energy resolution of ≈1 keV in the range of 3.5-15 keV and a maximum time resolution of 5 ms. A novel use of a Pilatus 2 hybrid-pixel x-ray detector [P. Kraft et al., J. Synchrotron Rad. 16, 368 (2009), 10.1107/S0909049509009911] is employed in which the lower energy threshold of individual pixels is adjusted, allowing regions of a single detector to be sensitive to different x-ray energy ranges. Development of this new detector calibration technique was done as a collaboration between PPPL and Dectris Ltd. The calibration procedure is described, and the energy resolution of the detector is characterized. Initial data from this installation on Alcator C-Mod is presented. This diagnostic provides line-integrated measurements of impurity emission which can be used to determine impurity concentrations as well as the electron energy distribution.

  13. Experimental task-based optimization of a four-camera variable-pinhole small-animal SPECT system

    Science.gov (United States)

    Hesterman, Jacob Y.; Kupinski, Matthew A.; Furenlid, Lars R.; Wilson, Donald W.

    2005-04-01

    We have previously utilized lumpy object models and simulated imaging systems in conjunction with the ideal observer to compute figures of merit for hardware optimization. In this paper, we describe the development of methods and phantoms necessary to validate or experimentally carry out these optimizations. Our study was conducted on a four-camera small-animal SPECT system that employs interchangeable pinhole plates to operate under a variety of pinhole configurations and magnifications (representing optimizable system parameters). We developed a small-animal phantom capable of producing random backgrounds for each image sequence. The task chosen for the study was the detection of a 2mm diameter sphere within the phantom-generated random background. A total of 138 projection images were used, half of which included the signal. As our observer, we employed the channelized Hotelling observer (CHO) with Laguerre-Gauss channels. The signal-to-noise (SNR) of this observer was used to compare different system configurations. Results indicate agreement between experimental and simulated data with higher detectability rates found for multiple-camera, multiple-pinhole, and high-magnification systems, although it was found that mixtures of magnifications often outperform systems employing a single magnification. This work will serve as a basis for future studies pertaining to system hardware optimization.

  14. An accurate and efficient system model of iterative image reconstruction in high-resolution pinhole SPECT for small animal research

    Energy Technology Data Exchange (ETDEWEB)

    Huang, P-C; Hsu, C-H [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan (China); Hsiao, I-T [Department Medical Imaging and Radiological Sciences, Chang Gung University, Tao-Yuan, Taiwan (China); Lin, K M [Medical Engineering Research Division, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan (China)], E-mail: cghsu@mx.nthu.edu.tw

    2009-06-15

    Accurate modeling of the photon acquisition process in pinhole SPECT is essential for optimizing resolution. In this work, the authors develop an accurate system model in which pinhole finite aperture and depth-dependent geometric sensitivity are explicitly included. To achieve high-resolution pinhole SPECT, the voxel size is usually set in the range of sub-millimeter so that the total number of image voxels increase accordingly. It is inevitably that a system matrix that models a variety of favorable physical factors will become extremely sophisticated. An efficient implementation for such an accurate system model is proposed in this research. We first use the geometric symmetries to reduce redundant entries in the matrix. Due to the sparseness of the matrix, only non-zero terms are stored. A novel center-to-radius recording rule is also developed to effectively describe the relation between a voxel and its related detectors at every projection angle. The proposed system matrix is also suitable for multi-threaded computing. Finally, the accuracy and effectiveness of the proposed system model is evaluated in a workstation equipped with two Quad-Core Intel X eon processors.

  15. Preliminary study on X-ray fluorescence computed tomography imaging of gold nanoparticles: Acceleration of data acquisition by multiple pinholes scheme

    Science.gov (United States)

    Sasaya, Tenta; Sunaguchi, Naoki; Seo, Seung-Jum; Hyodo, Kazuyuki; Zeniya, Tsutomu; Kim, Jong-Ki; Yuasa, Tetsuya

    2018-04-01

    Gold nanoparticles (GNPs) have recently attracted attention in nanomedicine as novel contrast agents for cancer imaging. A decisive tomographic imaging technique has not yet been established to depict the 3-D distribution of GNPs in an object. An imaging technique known as pinhole-based X-ray fluorescence computed tomography (XFCT) is a promising method that can be used to reconstruct the distribution of GNPs from the X-ray fluorescence emitted by GNPs. We address the acceleration of data acquisition in pinhole-based XFCT for preclinical use using a multiple pinhole scheme. In this scheme, multiple projections are simultaneously acquired through a multi-pinhole collimator with a 2-D detector and full-field volumetric beam to enhance the signal-to-noise ratio of the projections; this enables fast data acquisition. To demonstrate the efficacy of this method, we performed an imaging experiment using a physical phantom with an actual multi-pinhole XFCT system that was constructed using the beamline AR-NE7A at KEK. The preliminary study showed that the multi-pinhole XFCT achieved a data acquisition time of 20 min at a theoretical detection limit of approximately 0.1 Au mg/ml and at a spatial resolution of 0.4 mm.

  16. Genetics Home Reference: Amish lethal microcephaly

    Science.gov (United States)

    ... 1 in 500 newborns in the Old Order Amish population of Pennsylvania. It has not been found outside this population. Related Information What information about a genetic condition can statistics provide? Why are some genetic ... gene cause Amish lethal microcephaly . The SLC25A19 gene provides instructions for ...

  17. The evolution of lethal intergroup violence

    OpenAIRE

    Kelly, Raymond C.

    2005-01-01

    Recent findings and analyses in evolutionary biology, archaeology, and ethnology provide a favorable conjuncture for examining the evolution of lethal intergroup violence among hominids during the 2.9-million-year Paleolithic time span. Here, I seek to identify and investigate the main turning points in this evolutionary trajectory and to delineate the periodization that follows from this inquiry.

  18. The evolution of lethal intergroup violence.

    Science.gov (United States)

    Kelly, Raymond C

    2005-10-25

    Recent findings and analyses in evolutionary biology, archaeology, and ethnology provide a favorable conjuncture for examining the evolution of lethal intergroup violence among hominids during the 2.9-million-year Paleolithic time span. Here, I seek to identify and investigate the main turning points in this evolutionary trajectory and to delineate the periodization that follows from this inquiry.

  19. A new lethal sclerosing bone dysplasia

    International Nuclear Information System (INIS)

    Kingston, H.M.; Freeman, J.S.; Hall, C.M.

    1991-01-01

    A neonate is described with a lethal sclerosing bone dysplasia associated with prenatal fractures and craniofacial abnormalities including microcephaly, exophthalmos, hypoplastic nose and mid-face, small jaw and nodular hyperplasia of the gums. Parental consanguinity suggests that an autosomal recessive mutation is the likely aetiology. (orig.)

  20. Effect of the diameter and depth of pinholes on surface characteristics in the DC pulse plasma nitriding process

    International Nuclear Information System (INIS)

    Calahonra, M.C.G; Egidi, D.A; Svoboda, H; Corengia, P

    2006-01-01

    The ion nitriding treatment is a process widely used in steel alloys to improve the material's properties; such as surface hardness, resistance to wear, fatigue life and resistance to corrosion. But geometric changes in the components can produce during the nitriding process different effects on the behavior of the plasma, such as local variations in the electric field, an empty cathode effect, etc. These in turn can affect among other factors the local temperature and therefore the kinetics of the process, generating variations in the compound layer thicknesses and zone of diffusion, and micro-hardness profile. These heterogeneities limit the effectiveness of the plasma nitriding process, where control and duplication of the surface modification are most important. This work aims to study the effect of the geometry of the pieces treated with ionic nitriding, especially the effect of the orifices. An understanding of the operating mechanisms is sought in order to predict the development of the compound layer and zone of diffusion inside the pinholes. A series of orifices with different diameters and depths were machine made in AISI 4140 quenched and tempered cylindrical steel test pieces. The diameters analyzed were 2, 4, 6, 10 and 12 mm, while the depths studied were 3, 8 and 15 mm, resulting in 15 different configurations. The samples were nitrided by DC-pulse plasma in an industrial reactor, using a mixture of 75% H 2 - 25% N 2 , during 15 hours at a temperature of 500 o C. The nitrided test pieces were characterized with transverse sections using optic and scanning electron microscopy and Vickers micro-hardness profiles, measuring the thicknesses of white layer and zone of diffusion on the wall and base of the orifices. The results show that the sizes of the pinholes made in AISI 4140 steel greatly influence the uniformity and continuity of the compound layers and zones of diffusion. 'Critical diameters' for pinholes were also defined, underneath which the

  1. Synergistic Interaction Between Phage Therapy and Antibiotics Clears Pseudomonas Aeruginosa Infection in Endocarditis and Reduces Virulence.

    Science.gov (United States)

    Oechslin, Frank; Piccardi, Philippe; Mancini, Stefano; Gabard, Jérôme; Moreillon, Philippe; Entenza, José M; Resch, Gregory; Que, Yok-Ai

    2017-03-01

    Increasing antibiotic resistance warrants therapeutic alternatives. Here we investigated the efficacy of bacteriophage-therapy (phage) alone or combined with antibiotics against experimental endocarditis (EE) due to Pseudomonas aeruginosa, an archetype of difficult-to-treat infection. In vitro fibrin clots and rats with aortic EE were treated with an antipseudomonas phage cocktail alone or combined with ciprofloxacin. Phage pharmacology, therapeutic efficacy, and resistance were determined. In vitro, single-dose phage therapy killed 7 log colony-forming units (CFUs)/g of fibrin clots in 6 hours. Phage-resistant mutants regrew after 24 hours but were prevented by combination with ciprofloxacin (2.5 × minimum inhibitory concentration). In vivo, single-dose phage therapy killed 2.5 log CFUs/g of vegetations in 6 hours (P 6 log CFUs/g of vegetations in 6 hours and successfully treating 64% (n = 7/11) of rats. Phage-resistant mutants emerged in vitro but not in vivo, most likely because resistant mutations affected bacterial surface determinants important for infectivity (eg, the pilT and galU genes involved in pilus motility and LPS formation). Single-dose phage therapy was active against P. aeruginosa EE and highly synergistic with ciprofloxacin. Phage-resistant mutants had impaired infectivity. Phage-therapy alone or combined with antibiotics merits further clinical consideration. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.

  2. The Human Gut Phage Community and Its Implications for Health and Disease.

    Science.gov (United States)

    Manrique, Pilar; Dills, Michael; Young, Mark J

    2017-06-08

    In this review, we assess our current understanding of the role of bacteriophages infecting the human gut bacterial community in health and disease. In general, bacteriophages contribute to the structure of their microbial communities by driving host and viral diversification, bacterial evolution, and by expanding the functional diversity of ecosystems. Gut bacteriophages are an ensemble of unique and shared phages in individuals, which encompass temperate phages found predominately as prophage in gut bacteria (prophage reservoir) and lytic phages. In healthy individuals, only a small fraction of the prophage reservoir is activated and found as extracellular phages. Phage community dysbiosis is characterized by a shift in the activated prophage community or an increase of lytic phages, and has been correlated with disease, suggesting that a proper balance between lysis and lysogeny is needed to maintain health. Consequently, the concept of microbial dysbiosis might be extended to the phage component of the microbiome as well. Understanding the dynamics and mechanisms to restore balance after dysbiosis is an active area of research. The use of phage transplants to re-establish health suggests that phages can be used as disease treatment. Such advances represent milestones in our understanding of gut phages in human health and should fuel research on their role in health and disease.

  3. Ciprofloxacin and Trimethoprim Cause Phage Induction and Virulence Modulation in Staphylococcus aureus

    Science.gov (United States)

    Goerke, Christiane; Köller, Johanna; Wolz, Christiane

    2006-01-01

    In Staphylococcus aureus strains of human origin, phages which integrate into the chromosomal gene coding for β-hemolysin (hlb) are widely distributed. Most of them encode accessory virulence determinants such as staphylokinase (sak) or enterotoxins. Here, we analyzed the effects of ciprofloxacin and trimethoprim on phage induction and expression of phage-encoded virulence factors by using isolates from patients with cystic fibrosis for which the induction of hlb-converting phages was demonstrated in vivo (C. Goerke, S. Matias y Papenberg, S. Dasbach, K. Dietz, R. Ziebach, B. C. Kahl, and C. Wolz, J. Infect. Dis. 189:724-734, 2004) as well as a φ13 lysogen of phage-cured strain 8325-4. Treatment of lysogens with subinhibitory concentrations of either antibiotic resulted in (i) delysogenization of strains resembling the isolates picked up after chronic lung infection and (ii) replication of phages in the bacterial host in a dose-dependent manner. Ciprofloxacin treatment resulted in enhanced recA transcription, indicating involvement of the SOS response in phage mobilization. Induction of φ13 was linked to elevated expression of the phage-encoded virulence gene sak, chiefly due to the activation of latent phage promoters. In summary, we could show the induction of hlb-converting phages and a subsequent virulence modulation of the host bacterium by ciprofloxacin and trimethoprim. PMID:16377683

  4. Stochasticity in the Expression of LamB and its Affect on λ phage Infection

    Science.gov (United States)

    Chapman, Emily; Wu, Xiao-Lun

    2006-03-01

    λ phage binds to E. Coli's lamB protein and injects its DNA into the cell. The phage quickly replicates and after a latent period the bacteria bursts, emitting mature phages. We developed a mathematical model based on the known physical events that occur when a λ phage infects an E.Coli cell. The results of these models predict that the bacteria and phage populations become extinct unless the parameters of the model are very finely tuned, which is untrue in the nature. The lamB protein is part of the maltose regulon and can be repressed to minimal levels when grown in the absence of inducer. Therefore, a cell that is not expressing any lamB protein at that moment is resistant against phage infection. We studied the dynamic relationship between λ phage and E. Coli when the concentration of phage greatly outnumbers the concentration of bacteria. We study how the stochasticity of the expression of lamB affects the percentage of cells that the λ phage infects. We show that even in the case when the maltose regulon is fully induced a percentage of cells continue to persist against phage infection.

  5. Analysis of whole genome sequencing for the Escherichia coli O157:H7 typing phages.

    Science.gov (United States)

    Cowley, Lauren A; Beckett, Stephen J; Chase-Topping, Margo; Perry, Neil; Dallman, Tim J; Gally, David L; Jenkins, Claire

    2015-04-08

    Shiga toxin producing Escherichia coli O157 can cause severe bloody diarrhea and haemolytic uraemic syndrome. Phage typing of E. coli O157 facilitates public health surveillance and outbreak investigations, certain phage types are more likely to occupy specific niches and are associated with specific age groups and disease severity. The aim of this study was to analyse the genome sequences of 16 (fourteen T4 and two T7) E. coli O157 typing phages and to determine the genes responsible for the subtle differences in phage type profiles. The typing phages were sequenced using paired-end Illumina sequencing at The Genome Analysis Centre and the Animal Health and Veterinary Laboratories Agency and bioinformatics programs including Velvet, Brig and Easyfig were used to analyse them. A two-way Euclidian cluster analysis highlighted the associations between groups of phage types and typing phages. The analysis showed that the T7 typing phages (9 and 10) differed by only three genes and that the T4 typing phages formed three distinct groups of similar genomic sequences: Group 1 (1, 8, 11, 12 and 15, 16), Group 2 (3, 6, 7 and 13) and Group 3 (2, 4, 5 and 14). The E. coli O157 phage typing scheme exhibited a significantly modular network linked to the genetic similarity of each group showing that these groups are specialised to infect a subset of phage types. Sequencing the typing phage has enabled us to identify the variable genes within each group and to determine how this corresponds to changes in phage type.

  6. Mutagenesis of lambda phage by tif-expression or host-irradiation functions is largely independent of damage in the phage DNA

    International Nuclear Information System (INIS)

    Von Wright, A.; Bridges, B.A.

    1980-01-01

    The survival and mutagenesis of UV-irradiated phage lambda, as well as bacterial mutagenesis, are enhanced in tif mutants of Escherichia coli when these strains are grown at 43 0 C (Castellazzi et al., 1972). This was interpreted on the basis of a hypothesis (the SOS hypothesis) according to which the UV-inducible phenomena connected with reactivation and mutagenesis of UV-irradiated bacteriophages (Weigle, 1953; Radman, 1975) are constitutively expressed in tif-bacteria at high temperature (Witkin, 1974). In unpublished experiments with phage T3 we found that the survival of UV-irradiated phage is also better at 43 0 C than at 32 0 C in tif + cells and this made us reexamine the significance and nature of tif expression and examine its effects on both unirradiated and UV-irradiated phage lambda. Our results indicate that tif-induced mutagenesis and possibly reactivation of UV-irradiated phage lambda should be reinterpreted. (orig./AJ)

  7. Assessment of grass root effects on soil piping in sandy soils using the pinhole test

    Science.gov (United States)

    Bernatek-Jakiel, Anita; Vannoppen, Wouter; Poesen, Jean

    2017-10-01

    Soil piping is an important land degradation process that occurs in a wide range of environments. Despite an increasing number of studies on this type of subsurface erosion, the impact of vegetation on piping erosion is still unclear. It can be hypothesized that vegetation, and in particular plant roots, may reduce piping susceptibility of soils because roots of vegetation also control concentrated flow erosion rates or shallow mass movements. Therefore, this paper aims to assess the impact of grass roots on piping erosion susceptibility of a sandy soil. The pinhole test was used as it provides quantitative data on pipeflow discharge, sediment concentration and sediment discharge. Tests were conducted at different hydraulic heads (i.e., 50 mm, 180 mm, 380 mm and 1020 mm). Results showed that the hydraulic head was positively correlated with pipeflow discharge, sediment concentration and sediment discharge, while the presence of grass roots (expressed as root density) was negatively correlated with these pipeflow characteristics. Smaller sediment concentrations and sediment discharges were observed in root-permeated samples compared to root-free samples. When root density exceeds 0.5 kg m- 3, piping erosion rates decreased by 50% compared to root-free soil samples. Moreover, if grass roots are present, the positive correlation between hydraulic head and both sediment discharge and sediment concentration is less pronounced, demonstrating that grass roots become more effective in reducing piping erosion rates at larger hydraulic heads. Overall, this study demonstrates that grass roots are quite efficient in reducing piping erosion rates in sandy soils, even at high hydraulic head (> 1 m). As such, grass roots may therefore be used to efficiently control piping erosion rates in topsoils.

  8. Novel phage group infecting Lactobacillus delbrueckii subsp. lactis, as revealed by genomic and proteomic analysis of bacteriophage Ldl1.

    Science.gov (United States)

    Casey, Eoghan; Mahony, Jennifer; Neve, Horst; Noben, Jean-Paul; Dal Bello, Fabio; van Sinderen, Douwe

    2015-02-01

    Ldl1 is a virulent phage infecting the dairy starter Lactobacillus delbrueckii subsp. lactis LdlS. Electron microscopy analysis revealed that this phage exhibits a large head and a long tail and bears little resemblance to other characterized phages infecting Lactobacillus delbrueckii. In vitro propagation of this phage revealed a latent period of 30 to 40 min and a burst size of 59.9 +/- 1.9 phage particles. Comparative genomic and proteomic analyses showed remarkable similarity between the genome of Ldl1 and that of Lactobacillus plantarum phage ATCC 8014-B2. The genomic and proteomic characteristics of Ldl1 demonstrate that this phage does not belong to any of the four previously recognized L. delbrueckii phage groups, necessitating the creation of a new group, called group e, thus adding to the knowledge on the diversity of phages targeting strains of this industrially important lactic acid bacterial species.

  9. Characterization of Lipoteichoic Acids as Lactobacillus delbrueckii Phage Receptor Components

    OpenAIRE

    Räisänen, Liisa; Schubert, Karin; Jaakonsaari, Tiina; Alatossava, Tapani

    2004-01-01

    Lipoteichoic acids (LTAs) were purified from Lactobacillus delbrueckii subsp. lactis ATCC 15808 and its LL-H adsorption-resistant mutant, Ads-5, by hydrophobic interaction chromatography. L. delbrueckii phages (LL-H, the LL-H host range mutant, and JCL1032) were inactivated by these poly(glycerophosphate) type of LTAs in vitro in accordance to their adsorption to intact ATCC 15808 and Ads-5 cells.

  10. Characterization of Lipoteichoic Acids as Lactobacillus delbrueckii Phage Receptor Components

    Science.gov (United States)

    Räisänen, Liisa; Schubert, Karin; Jaakonsaari, Tiina; Alatossava, Tapani

    2004-01-01

    Lipoteichoic acids (LTAs) were purified from Lactobacillus delbrueckii subsp. lactis ATCC 15808 and its LL-H adsorption-resistant mutant, Ads-5, by hydrophobic interaction chromatography. L. delbrueckii phages (LL-H, the LL-H host range mutant, and JCL1032) were inactivated by these poly(glycerophosphate) type of LTAs in vitro in accordance to their adsorption to intact ATCC 15808 and Ads-5 cells. PMID:15292157

  11. Characterization of Campylobacter phages including analysis of host range by selected Campylobacter Penner serotypes

    DEFF Research Database (Denmark)

    Hansen, Vinni; Rosenquist, Hanne; Baggesen, Dorte Lau

    2007-01-01

    range often displayed by phages. To identify the potential of phages as a Campylobacter reducing agent we needed to determine their infectivity on a panel of isolates representing the Campylobacter strains found in broilers as well as humans. Results: In this study, Campylobacter phages were isolated...... from the intestines of broilers and ducks and from abattoir sewage. Twelve phages were investigated to determine their ability to infect the Campylobacter Penner serotypes commonly present in Danish poultry and patients with campylobacteriosis. A total of 89% of the Campylobacter jejuni strains and 14...... range of 12 Danish Campylobacter phages. Due to their ability to infect the majority of the common serotypes in Denmark we suggest the phages can become an effective agent in the effort to reduce the incidence of campylobacteriosis in Denmark. This study provides the basis for future experiments...

  12. Filamentous phages of Ralstonia solanacearum: double-edged swords for pathogenic bacteria.

    Science.gov (United States)

    Yamada, Takashi

    2013-01-01

    Some phages from genus Inovirus use host or bacteriophage-encoded site-specific integrases or recombinases establish a prophage state. During integration or excision, a superinfective form can be produced. The three states (free, prophage, and superinfective) of such phages exert different effects on host bacterial phenotypes. In Ralstonia solanacearum, the causative agent of bacterial wilt disease of crops, the bacterial virulence can be positively or negatively affected by filamentous phages, depending on their state. The presence or absence of a repressor gene in the phage genome may be responsible for the host phenotypic differences (virulent or avirulent) caused by phage infection. This strategy of virulence control may be widespread among filamentous phages that infect pathogenic bacteria of plants.

  13. The phage-host arms race: Shaping the evolution of microbes

    Energy Technology Data Exchange (ETDEWEB)

    Stern, Adi [Weizmann Inst. of Science, Rehovot (Israel). Dept. of Molecular Genetics; Sorek, Rotem [Weizmann Inst. of Science, Rehovot (Israel). Dept. of Molecular Genetics

    2010-10-26

    Bacteria, the most abundant organisms on the planet, are outnumbered by a factor of 10 to 1 by phages that infect them. Faced with the rapid evolution and turnover of phage particles, bacteria have evolved various mechanisms to evade phage infection and killing, leading to an evolutionary arms race. The extensive co-evolution of both phage and host has resulted in considerable diversity on the part of both bacterial and phage defensive and offensive strategies. In this paper, we discuss the unique and common features of phage resistance mechanisms and their role in global biodiversity. Finally, the commonalities between defense mechanisms suggest avenues for the discovery of novel forms of these mechanisms based on their evolutionary traits.

  14. Genomic analysis of WCP30 Phage of Weissella cibaria for Dairy Fermented Foods.

    Science.gov (United States)

    Lee, Young-Duck; Park, Jong-Hyun

    2017-01-01

    In this study, we report the morphogenetic analysis and genome sequence of a new WCP30 phage of Weissella cibaria , isolated from a fermented food. Based on its morphology, as observed by transmission electron microscopy, WCP30 phage belongs to the family Siphoviridae . Genomic analysis of WCP30 phage showed that it had a 33,697-bp double-stranded DNA genome with 41.2% G+C content. Bioinformatics analysis of the genome revealed 35 open reading frames. A BLASTN search showed that WCP30 phage had low sequence similarity compared to other phages infecting lactic acid bacteria. This is the first report of the morphological features and complete genome sequence of WCP30 phage, which may be useful for controlling the fermentation of dairy foods.

  15. Lethal neonatal short-limbed dwarfism

    International Nuclear Information System (INIS)

    Kim, Ok Hwa; Yim, Chung Ik; Bahk, Yong Whee

    1986-01-01

    We have detailed our experiences on 6 cases of neonatal lethal short-limbed dwarfism and reviewed the articles. They include, achondrogenesis, thanatophoric dysplasia, asphyxiating thoracic dysplasia, osteogenesis imperfect a congenita, and hypophosphatasia lethals. Five babies were born alive but died soon after birth and one was a stillbirth. The main cause of failure to thrive was respiratory insufficiency. Each case was having quite characteristic radiologic findings, even if the general appearances were similar to the achondroplasts clinically. Precise diagnosis is very important for genetic counselling of the parents and alarm to them the possibility of bone dysplasias to the next offsprings. For this purpose, the radiologists play major role for the correct diagnosis. We stress that when the baby is born with short-limbed dwarfism, whole body radiogram should be taken including lateral view and postmortem radiogram is also very precious.

  16. Lethal neonatal short-limbed dwarfism

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ok Hwa; Yim, Chung Ik; Bahk, Yong Whee [Catholic Medical College, Seoul (Korea, Republic of)

    1986-02-15

    We have detailed our experiences on 6 cases of neonatal lethal short-limbed dwarfism and reviewed the articles. They include, achondrogenesis, thanatophoric dysplasia, asphyxiating thoracic dysplasia, osteogenesis imperfect a congenita, and hypophosphatasia lethals. Five babies were born alive but died soon after birth and one was a stillbirth. The main cause of failure to thrive was respiratory insufficiency. Each case was having quite characteristic radiologic findings, even if the general appearances were similar to the achondroplasts clinically. Precise diagnosis is very important for genetic counselling of the parents and alarm to them the possibility of bone dysplasias to the next offsprings. For this purpose, the radiologists play major role for the correct diagnosis. We stress that when the baby is born with short-limbed dwarfism, whole body radiogram should be taken including lateral view and postmortem radiogram is also very precious.

  17. Mining of lethal recessive genetic variation in Danish cattle

    DEFF Research Database (Denmark)

    Das, Ashutosh

    2015-01-01

    in fertility. The primary objective of this PhD projekt was to identify recessive lethal gentic variants in the main Danish dairy cattle breed. Holstein-Friesian utilzing next generation sequencing (NGS) data. This study shows a potential for the use of the NGS-based reverse genetic approach in identifying...... lethal or semi-lethal recessive gentic variation...

  18. Phage “delay” towards enhancing bacterial escape from biofilms: a more comprehensive way of viewing resistance to bacteriophages

    Directory of Open Access Journals (Sweden)

    Stephen T. Abedon

    2017-03-01

    Full Text Available In exploring bacterial resistance to bacteriophages, emphasis typically is placed on those mechanisms which completely prevent phage replication. Such resistance can be detected as extensive reductions in phage ability to form plaques, that is, reduced efficiency of plating. Mechanisms include restriction-modification systems, CRISPR/Cas systems, and abortive infection systems. Alternatively, phages may be reduced in their “vigor” when infecting certain bacterial hosts, that is, with phages displaying smaller burst sizes or extended latent periods rather than being outright inactivated. It is well known, as well, that most phages poorly infect bacteria that are less metabolically active. Extracellular polymers such as biofilm matrix material also may at least slow phage penetration to bacterial surfaces. Here I suggest that such “less-robust” mechanisms of resistance to bacteriophages could serve bacteria by slowing phage propagation within bacterial biofilms, that is, delaying phage impact on multiple bacteria rather than necessarily outright preventing such impact. Related bacteria, ones that are relatively near to infected bacteria, e.g., roughly 10+ µm away, consequently may be able to escape from biofilms with greater likelihood via standard dissemination-initiating mechanisms including erosion from biofilm surfaces or seeding dispersal/central hollowing. That is, given localized areas of phage infection, so long as phage spread can be reduced in rate from initial points of contact with susceptible bacteria, then bacterial survival may be enhanced due to bacteria metaphorically “running away” to more phage-free locations. Delay mechanisms—to the extent that they are less specific in terms of what phages are targeted—collectively could represent broader bacterial strategies of phage resistance versus outright phage killing, the latter especially as require specific, evolved molecular recognition of phage presence. The

  19. Advances in phage display technology for drug discovery.

    Science.gov (United States)

    Omidfar, Kobra; Daneshpour, Maryam

    2015-06-01

    Over the past decade, several library-based methods have been developed to discover ligands with strong binding affinities for their targets. These methods mimic the natural evolution for screening and identifying ligand-target interactions with specific functional properties. Phage display technology is a well-established method that has been applied to many technological challenges including novel drug discovery. This review describes the recent advances in the use of phage display technology for discovering novel bioactive compounds. Furthermore, it discusses the application of this technology to produce proteins and peptides as well as minimize the use of antibodies, such as antigen-binding fragment, single-chain fragment variable or single-domain antibody fragments like VHHs. Advances in screening, manufacturing and humanization technologies demonstrate that phage display derived products can play a significant role in the diagnosis and treatment of disease. The effects of this technology are inevitable in the development pipeline for bringing therapeutics into the market, and this number is expected to rise significantly in the future as new advances continue to take place in display methods. Furthermore, a widespread application of this methodology is predicted in different medical technological areas, including biosensing, monitoring, molecular imaging, gene therapy, vaccine development and nanotechnology.

  20. Phage display peptide libraries: deviations from randomness and correctives

    Science.gov (United States)

    Ryvkin, Arie; Ashkenazy, Haim; Weiss-Ottolenghi, Yael; Piller, Chen; Pupko, Tal; Gershoni, Jonathan M

    2018-01-01

    Abstract Peptide-expressing phage display libraries are widely used for the interrogation of antibodies. Affinity selected peptides are then analyzed to discover epitope mimetics, or are subjected to computational algorithms for epitope prediction. A critical assumption for these applications is the random representation of amino acids in the initial naïve peptide library. In a previous study, we implemented next generation sequencing to evaluate a naïve library and discovered severe deviations from randomness in UAG codon over-representation as well as in high G phosphoramidite abundance causing amino acid distribution biases. In this study, we demonstrate that the UAG over-representation can be attributed to the burden imposed on the phage upon the assembly of the recombinant Protein 8 subunits. This was corrected by constructing the libraries using supE44-containing bacteria which suppress the UAG driven abortive termination. We also demonstrate that the overabundance of G stems from variant synthesis-efficiency and can be corrected using compensating oligonucleotide-mixtures calibrated by mass spectroscopy. Construction of libraries implementing these correctives results in markedly improved libraries that display random distribution of amino acids, thus ensuring that enriched peptides obtained in biopanning represent a genuine selection event, a fundamental assumption for phage display applications. PMID:29420788

  1. Probing ADAMTS13 Substrate Specificity using Phage Display

    Science.gov (United States)

    Desch, Karl C.; Kretz, Colin; Yee, Andrew; Gildersleeve, Robert; Metzger, Kristin; Agrawal, Nidhi; Cheng, Jane; Ginsburg, David

    2015-01-01

    Von Willebrand factor (VWF) is a large, multimeric protein that regulates hemostasis by tethering platelets to the subendothelial matrix at sites of vascular damage. The procoagulant activity of plasma VWF correlates with the length of VWF multimers, which is proteolytically controlled by the metalloprotease ADAMTS13. To probe ADAMTS13 substrate specificity, we created phage display libraries containing randomly mutated residues of a minimal ADAMTS13 substrate fragment of VWF, termed VWF73. The libraries were screened for phage particles displaying VWF73 mutant peptides that were resistant to proteolysis by ADAMTS13. These peptides exhibited the greatest mutation frequency near the ADAMTS13 scissile residues. Kinetic assays using mutant and wild-type substrates demonstrated excellent agreement between rates of cleavage for mutant phage particles and the corresponding mutant peptides. Cleavage resistance of selected mutations was tested in vivo using hydrodynamic injection of corresponding full-length expression plasmids into VWF-deficient mice. These studies confirmed the resistance to cleavage resulting from select amino acid substitutions and uncovered evidence of alternate cleavage sites and recognition by other proteases in the circulation of ADAMTS13 deficient mice. Taken together, these studies demonstrate the key role of specific amino acids residues including P3-P2’ and P11’, for substrate specificity and emphasize the importance in flowing blood of other ADAMTS13–VWF exosite interactions outside of VWF73. PMID:25849793

  2. Probing ADAMTS13 substrate specificity using phage display.

    Directory of Open Access Journals (Sweden)

    Karl C Desch

    Full Text Available Von Willebrand factor (VWF is a large, multimeric protein that regulates hemostasis by tethering platelets to the subendothelial matrix at sites of vascular damage. The procoagulant activity of plasma VWF correlates with the length of VWF multimers, which is proteolytically controlled by the metalloprotease ADAMTS13. To probe ADAMTS13 substrate specificity, we created phage display libraries containing randomly mutated residues of a minimal ADAMTS13 substrate fragment of VWF, termed VWF73. The libraries were screened for phage particles displaying VWF73 mutant peptides that were resistant to proteolysis by ADAMTS13. These peptides exhibited the greatest mutation frequency near the ADAMTS13 scissile residues. Kinetic assays using mutant and wild-type substrates demonstrated excellent agreement between rates of cleavage for mutant phage particles and the corresponding mutant peptides. Cleavage resistance of selected mutations was tested in vivo using hydrodynamic injection of corresponding full-length expression plasmids into VWF-deficient mice. These studies confirmed the resistance to cleavage resulting from select amino acid substitutions and uncovered evidence of alternate cleavage sites and recognition by other proteases in the circulation of ADAMTS13 deficient mice. Taken together, these studies demonstrate the key role of specific amino acids residues including P3-P2' and P11', for substrate specificity and emphasize the importance in flowing blood of other ADAMTS13-VWF exosite interactions outside of VWF73.

  3. Aptamer-Phage Reporters for Ultrasensitive Lateral Flow Assays.

    Science.gov (United States)

    Adhikari, Meena; Strych, Ulrich; Kim, Jinsu; Goux, Heather; Dhamane, Sagar; Poongavanam, Mohan-Vivekanandan; Hagström, Anna E V; Kourentzi, Katerina; Conrad, Jacinta C; Willson, Richard C

    2015-12-01

    We introduce the modification of bacteriophage particles with aptamers for use as bioanalytical reporters, and demonstrate the use of these particles in ultrasensitive lateral flow assays. M13 phage displaying an in vivo biotinylatable peptide (AviTag) genetically fused to the phage tail protein pIII were used as reporter particle scaffolds, with biotinylated aptamers attached via avidin-biotin linkages, and horseradish peroxidase (HRP) reporter enzymes covalently attached to the pVIII coat protein. These modified viral nanoparticles were used in immunochromatographic sandwich assays for the direct detection of IgE and of the penicillin-binding protein from Staphylococcus aureus (PBP2a). We also developed an additional lateral flow assay for IgE, in which the analyte is sandwiched between immobilized anti-IgE antibodies and aptamer-bearing reporter phage modified with HRP. The limit of detection of this LFA was 0.13 ng/mL IgE, ∼100 times lower than those of previously reported IgE assays.

  4. Lethal midline granuloma syndrome: a diagnostic dilemma

    International Nuclear Information System (INIS)

    Ribeiro, Bruno Niemeyer de Freitas; Bahia, Paulo Roberto Valle; Oliveira, Ana Luiza Vianna Sobral de Magalhaes; Marchon Junior, Joao Luiz

    2012-01-01

    The rare lethal midline granuloma syndrome is difficult to diagnose because of the wide array of related diseases and lack of knowledge by the majority of physicians. In the present report, the authors describe the case of a patient with this disease, caused by squamous cell carcinoma, drawing attention to differential diagnoses and to clinical and radiological findings that may be useful to define the diagnosis. (author)

  5. Lethal Interpersonal Violence in the Middle Pleistocene

    OpenAIRE

    Sala, Nohemi; Arsuaga, Juan Luis; Pantoja-P?rez, Ana; Pablos, Adri?n; Mart?nez, Ignacio; Quam, Rolf M.; G?mez-Olivencia, Asier; Berm?dez de Castro, Jos? Mar?a; Carbonell, Eudald

    2015-01-01

    Evidence of interpersonal violence has been documented previously in Pleistocene members of the genus Homo, but only very rarely has this been posited as the possible manner of death. Here we report the earliest evidence of lethal interpersonal violence in the hominin fossil record. Cranium 17 recovered from the Sima de los Huesos Middle Pleistocene site shows two clear perimortem depression fractures on the frontal bone, interpreted as being produced by two episodes of localized blunt force ...

  6. Lethal midline granuloma syndrome: a diagnostic dilemma

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Bruno Niemeyer de Freitas; Bahia, Paulo Roberto Valle [Radiology, Hospital Universitario Clementino Fraga Filho - Universidade Federal do Rio de Janeiro (HUCFF-UFRJ), Rio de Janeiro, RJ (Brazil); Oliveira, Ana Luiza Vianna Sobral de Magalhaes [Resident of Medical Practice, Hospital Federal da Lagoa, Rio de Janeiro, RJ (Brazil); Marchon Junior, Joao Luiz [Unit of Computed Tomography, Hospital Federal da Lagoa, Rio de Janeiro, RJ (Brazil)

    2012-11-15

    The rare lethal midline granuloma syndrome is difficult to diagnose because of the wide array of related diseases and lack of knowledge by the majority of physicians. In the present report, the authors describe the case of a patient with this disease, caused by squamous cell carcinoma, drawing attention to differential diagnoses and to clinical and radiological findings that may be useful to define the diagnosis. (author)

  7. Lethal interpersonal violence in the Middle Pleistocene.

    Directory of Open Access Journals (Sweden)

    Nohemi Sala

    Full Text Available Evidence of interpersonal violence has been documented previously in Pleistocene members of the genus Homo, but only very rarely has this been posited as the possible manner of death. Here we report the earliest evidence of lethal interpersonal violence in the hominin fossil record. Cranium 17 recovered from the Sima de los Huesos Middle Pleistocene site shows two clear perimortem depression fractures on the frontal bone, interpreted as being produced by two episodes of localized blunt force trauma. The type of injuries, their location, the strong similarity of the fractures in shape and size, and the different orientations and implied trajectories of the two fractures suggest they were produced with the same object in face-to-face interpersonal conflict. Given that either of the two traumatic events was likely lethal, the presence of multiple blows implies an intention to kill. This finding shows that the lethal interpersonal violence is an ancient human behavior and has important implications for the accumulation of bodies at the site, supporting an anthropic origin.

  8. Lethal interpersonal violence in the Middle Pleistocene.

    Science.gov (United States)

    Sala, Nohemi; Arsuaga, Juan Luis; Pantoja-Pérez, Ana; Pablos, Adrián; Martínez, Ignacio; Quam, Rolf M; Gómez-Olivencia, Asier; Bermúdez de Castro, José María; Carbonell, Eudald

    2015-01-01

    Evidence of interpersonal violence has been documented previously in Pleistocene members of the genus Homo, but only very rarely has this been posited as the possible manner of death. Here we report the earliest evidence of lethal interpersonal violence in the hominin fossil record. Cranium 17 recovered from the Sima de los Huesos Middle Pleistocene site shows two clear perimortem depression fractures on the frontal bone, interpreted as being produced by two episodes of localized blunt force trauma. The type of injuries, their location, the strong similarity of the fractures in shape and size, and the different orientations and implied trajectories of the two fractures suggest they were produced with the same object in face-to-face interpersonal conflict. Given that either of the two traumatic events was likely lethal, the presence of multiple blows implies an intention to kill. This finding shows that the lethal interpersonal violence is an ancient human behavior and has important implications for the accumulation of bodies at the site, supporting an anthropic origin.

  9. An efficient method for isolating antibody fragments against small peptides by antibody phage display

    DEFF Research Database (Denmark)

    Duan, Zhi; Siegumfeldt, Henrik

    2010-01-01

    We generated monoclonal scFv (single chain variable fragment) antibodies from an antibody phage display library towards three small synthetic peptides derived from the sequence of s1-casein. Key difficulties for selection of scFv-phages against small peptides were addressed. Small peptides do....... The scFvs were sequenced and characterized, and specificity was characterized by ELISA. The methods developed in this study are universally applicable for antibody phage display to efficiently produce antibody fragments against small peptides....

  10. Impedance Measurements Could Accelerate Phage-Based Identification of Bacillus anthracis and Other Bacteria

    Science.gov (United States)

    2016-09-01

    Impedance Measurements Could Accelerate Phage-Based Identification of Bacillus anthracis And Other Bacteria Thomas Brown, Salwa Shan, Teresa...infection can be detected as early as one hour after exposing as few as 105 CFU bacteria to the stressor. We predicted that similar responses could be used... bacteria to form confluent growth and for phage-induced plaques to appear. Techniques that permit faster detection of species-specific bacteria /phage

  11. Analysis of Lactobacillus Products for Phages and Bacteriocins That Inhibit Vaginal Lactobacilli

    Directory of Open Access Journals (Sweden)

    Lin Tao

    1997-01-01

    Full Text Available Objective: Bacterial vaginosis is associated with an unexplained loss of vaginal lactobacilli. Previously, we have identified certain vaginal lactobacilli-released phages that can inhibit in vitro other vaginal lactobacilli. However, there is no apparent route for phages to be transmitted among women. The purpose of this study was to identify whether certain Lactobacillus products commonly used by women release phages or bacteriocins that can inhibit vaginal lactobacilli.

  12. Viruses in the marine environment: community dynamics, phage-host interactions and genomic structure

    OpenAIRE

    Lara de la Casa, Elena

    2014-01-01

    There are an estimated 1030 viruses in the world oceans, the majority of which are phages (viruses that infect bacteria). Extensive research has demonstrated the significant influence of marine phages on microbial abundance, community structure, genetic exchange and global biogeochemical cycles. In this thesis, we contribute to increase the knowledge about the ecological role of viruses in marine systems, but also we aimed to provide a better understanding about the interactions between phage...

  13. Directed synthesis of bio-inorganic vanadium oxide composites using genetically modified filamentous phage

    International Nuclear Information System (INIS)

    Mueller, Michael; Baik, Seungyun; Jeon, Hojeong; Kim, Yuchan; Kim, Jungtae; Kim, Young Jun

    2015-01-01

    Highlights: • Phage is an excellent seeding for bio-templates for environmentally benign vanadium oxide nanocomposite synthesis. • The synthesized bio-inorganic vanadium oxide showed photodegradation activities. • The fabricated wt phage/vanadium oxide composite exhibited bundle-like structure. • The fabricated RSTB-phage/vanadium oxide composite exhibited a ball with a fiber-like nanostructure. • The virus/vanadium oxide composite could be applied in photocatalysts, sensors and nanoelectronic applications. - Abstract: The growth of crystalline vanadium oxide using a filamentous bacteriophage template was investigated using sequential incubation in a V 2 O 5 precursor. Using the genetic modification of the bacteriophage, we displayed two cysteines that constrained the RSTB-1 peptide on the major coat protein P8, resulting in vanadium oxide crystallization. The phage-driven vanadium oxide crystals with different topologies, microstructures, photodegradation and vanadium oxide composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), quartz microbalance and dissipation (QCM-D) and X-ray photoelectron spectroscopy (XPS). Non-specific electrostatic attraction between a wild-type phage (wt-phage) and vanadium cations in the V 2 O 5 precursor caused phage agglomeration and fiber formation along the length of the viral scaffold. As a result, the addition of recombinant phage (re-phage) in V 2 O 5 precursors formed heterogeneous structures, which led to efficient condensation of vanadium oxide crystal formation in lines, shown by QCM-D analysis. Furthermore, re-phage/V x O x composites showed significantly enhanced photodegradation activities compared with the synthesized wt-phage-V 2 O 5 composite under illumination. This study demonstrates that peptide-mediated vanadium oxide mineralization is governed by a complicated interplay of peptide sequence, local structure, kinetics and the presence of a mineralizing

  14. Tales of diversity: Genomic and morphological characteristics of forty-six Arthrobacter phages.

    Directory of Open Access Journals (Sweden)

    Karen K Klyczek

    Full Text Available The vast bacteriophage population harbors an immense reservoir of genetic information. Almost 2000 phage genomes have been sequenced from phages infecting hosts in the phylum Actinobacteria, and analysis of these genomes reveals substantial diversity, pervasive mosaicism, and novel mechanisms for phage replication and lysogeny. Here, we describe the isolation and genomic characterization of 46 phages from environmental samples at various geographic locations in the U.S. infecting a single Arthrobacter sp. strain. These phages include representatives of all three virion morphologies, and Jasmine is the first sequenced podovirus of an actinobacterial host. The phages also span considerable sequence diversity, and can be grouped into 10 clusters according to their nucleotide diversity, and two singletons each with no close relatives. However, the clusters/singletons appear to be genomically well separated from each other, and relatively few genes are shared between clusters. Genome size varies from among the smallest of siphoviral phages (15,319 bp to over 70 kbp, and G+C contents range from 45-68%, compared to 63.4% for the host genome. Although temperate phages are common among other actinobacterial hosts, these Arthrobacter phages are primarily lytic, and only the singleton Galaxy is likely temperate.

  15. Efficient identification of phosphatidylserine-binding proteins by ORF phage display

    International Nuclear Information System (INIS)

    Caberoy, Nora B.; Zhou, Yixiong; Alvarado, Gabriela; Fan, Xianqun; Li, Wei

    2009-01-01

    To efficiently elucidate the biological roles of phosphatidylserine (PS), we developed open-reading-frame (ORF) phage display to identify PS-binding proteins. The procedure of phage panning was optimized with a phage clone expressing MFG-E8, a well-known PS-binding protein. Three rounds of phage panning with ORF phage display cDNA library resulted in ∼300-fold enrichment in PS-binding activity. A total of 17 PS-binding phage clones were identified. Unlike phage display with conventional cDNA libraries, all 17 PS-binding clones were ORFs encoding 13 real proteins. Sequence analysis revealed that all identified PS-specific phage clones had dimeric basic amino acid residues. GST fusion proteins were expressed for 3 PS-binding proteins and verified for their binding activity to PS liposomes, but not phosphatidylcholine liposomes. These results elucidated previously unknown PS-binding proteins and demonstrated that ORF phage display is a versatile technology capable of efficiently identifying binding proteins for non-protein molecules like PS.

  16. Inhaled phage therapy: a promising and challenging approach to treat bacterial respiratory infections.

    Science.gov (United States)

    Bodier-Montagutelli, Elsa; Morello, Eric; L'Hostis, Guillaume; Guillon, Antoine; Dalloneau, Emilie; Respaud, Renaud; Pallaoro, Nikita; Blois, Hélène; Vecellio, Laurent; Gabard, Jérôme; Heuzé-Vourc'h, Nathalie

    2017-08-01

    Bacterial respiratory tract infections (RTIs) are increasingly difficult to treat due to evolving antibiotic resistance. In this context, bacteriophages (or phages) are part of the foreseen alternatives or combination therapies. Delivering phages through the airways seems more relevant to accumulate these natural antibacterial viruses in proximity to their bacterial host, within the infectious site. Areas covered: This review addresses the potential of phage therapy to treat RTIs and discusses preclinical and clinical results of phages administration in this context. Recent phage formulation and aerosolization attempts are also reviewed, raising technical challenges to achieve efficient pulmonary deposition via inhalation. Expert opinion: Overall, the inhalation of phages as antibacterial treatment seems both clinically relevant and technically feasible. Several crucial points still need to be investigated, such as phage product pharmacokinetics and immunogenicity. Furthermore, given phage-specific features, appropriate regulatory and manufacturing guidelines will need to be defined. Finally, randomized controlled clinical trials should be carried out to establish phage therapy's clinical positioning in the antimicrobial arsenal against RTIs.

  17. Phage morphology recapitulates phylogeny: the comparative genomics of a new group of myoviruses.

    Directory of Open Access Journals (Sweden)

    André M Comeau

    Full Text Available Among dsDNA tailed bacteriophages (Caudovirales, members of the Myoviridae family have the most sophisticated virion design that includes a complex contractile tail structure. The Myoviridae generally have larger genomes than the other phage families. Relatively few "dwarf" myoviruses, those with a genome size of less than 50 kb such as those of the Mu group, have been analyzed in extenso. Here we report on the genome sequencing and morphological characterization of a new group of such phages that infect a diverse range of Proteobacteria, namely Aeromonas salmonicida phage 56, Vibrio cholerae phages 138 and CP-T1, Bdellovibrio phage φ1422, and Pectobacterium carotovorum phage ZF40. This group of dwarf myoviruses shares an identical virion morphology, characterized by usually short contractile tails, and have genome sizes of approximately 45 kb. Although their genome sequences are variable in their lysogeny, replication, and host adaption modules, presumably reflecting differing lifestyles and hosts, their structural and morphogenesis modules have been evolutionarily constrained by their virion morphology. Comparative genomic analysis reveals that these phages, along with related prophage genomes, form a new coherent group within the Myoviridae. The results presented in this communication support the hypothesis that the diversity of phages may be more structured than generally believed and that the innumerable phages in the biosphere all belong to discrete lineages or families.

  18. Tales of diversity: Genomic and morphological characteristics of forty-six Arthrobacter phages.

    Science.gov (United States)

    Klyczek, Karen K; Bonilla, J Alfred; Jacobs-Sera, Deborah; Adair, Tamarah L; Afram, Patricia; Allen, Katherine G; Archambault, Megan L; Aziz, Rahat M; Bagnasco, Filippa G; Ball, Sarah L; Barrett, Natalie A; Benjamin, Robert C; Blasi, Christopher J; Borst, Katherine; Braun, Mary A; Broomell, Haley; Brown, Conner B; Brynell, Zachary S; Bue, Ashley B; Burke, Sydney O; Casazza, William; Cautela, Julia A; Chen, Kevin; Chimalakonda, Nitish S; Chudoff, Dylan; Connor, Jade A; Cross, Trevor S; Curtis, Kyra N; Dahlke, Jessica A; Deaton, Bethany M; Degroote, Sarah J; DeNigris, Danielle M; DeRuff, Katherine C; Dolan, Milan; Dunbar, David; Egan, Marisa S; Evans, Daniel R; Fahnestock, Abby K; Farooq, Amal; Finn, Garrett; Fratus, Christopher R; Gaffney, Bobby L; Garlena, Rebecca A; Garrigan, Kelly E; Gibbon, Bryan C; Goedde, Michael A; Guerrero Bustamante, Carlos A; Harrison, Melinda; Hartwell, Megan C; Heckman, Emily L; Huang, Jennifer; Hughes, Lee E; Hyduchak, Kathryn M; Jacob, Aswathi E; Kaku, Machika; Karstens, Allen W; Kenna, Margaret A; Khetarpal, Susheel; King, Rodney A; Kobokovich, Amanda L; Kolev, Hannah; Konde, Sai A; Kriese, Elizabeth; Lamey, Morgan E; Lantz, Carter N; Lapin, Jonathan S; Lawson, Temiloluwa O; Lee, In Young; Lee, Scott M; Lee-Soety, Julia Y; Lehmann, Emily M; London, Shawn C; Lopez, A Javier; Lynch, Kelly C; Mageeney, Catherine M; Martynyuk, Tetyana; Mathew, Kevin J; Mavrich, Travis N; McDaniel, Christopher M; McDonald, Hannah; McManus, C Joel; Medrano, Jessica E; Mele, Francis E; Menninger, Jennifer E; Miller, Sierra N; Minick, Josephine E; Nabua, Courtney T; Napoli, Caroline K; Nkangabwa, Martha; Oates, Elizabeth A; Ott, Cassandra T; Pellerino, Sarah K; Pinamont, William J; Pirnie, Ross T; Pizzorno, Marie C; Plautz, Emilee J; Pope, Welkin H; Pruett, Katelyn M; Rickstrew, Gabbi; Rimple, Patrick A; Rinehart, Claire A; Robinson, Kayla M; Rose, Victoria A; Russell, Daniel A; Schick, Amelia M; Schlossman, Julia; Schneider, Victoria M; Sells, Chloe A; Sieker, Jeremy W; Silva, Morgan P; Silvi, Marissa M; Simon, Stephanie E; Staples, Amanda K; Steed, Isabelle L; Stowe, Emily L; Stueven, Noah A; Swartz, Porter T; Sweet, Emma A; Sweetman, Abigail T; Tender, Corrina; Terry, Katrina; Thomas, Chrystal; Thomas, Daniel S; Thompson, Allison R; Vanderveen, Lorianna; Varma, Rohan; Vaught, Hannah L; Vo, Quynh D; Vonberg, Zachary T; Ware, Vassie C; Warrad, Yasmene M; Wathen, Kaitlyn E; Weinstein, Jonathan L; Wyper, Jacqueline F; Yankauskas, Jakob R; Zhang, Christine; Hatfull, Graham F

    2017-01-01

    The vast bacteriophage population harbors an immense reservoir of genetic information. Almost 2000 phage genomes have been sequenced from phages infecting hosts in the phylum Actinobacteria, and analysis of these genomes reveals substantial diversity, pervasive mosaicism, and novel mechanisms for phage replication and lysogeny. Here, we describe the isolation and genomic characterization of 46 phages from environmental samples at various geographic locations in the U.S. infecting a single Arthrobacter sp. strain. These phages include representatives of all three virion morphologies, and Jasmine is the first sequenced podovirus of an actinobacterial host. The phages also span considerable sequence diversity, and can be grouped into 10 clusters according to their nucleotide diversity, and two singletons each with no close relatives. However, the clusters/singletons appear to be genomically well separated from each other, and relatively few genes are shared between clusters. Genome size varies from among the smallest of siphoviral phages (15,319 bp) to over 70 kbp, and G+C contents range from 45-68%, compared to 63.4% for the host genome. Although temperate phages are common among other actinobacterial hosts, these Arthrobacter phages are primarily lytic, and only the singleton Galaxy is likely temperate.

  19. Phage Therapy Is Effective in a Mouse Model of Bacterial Equine Keratitis.

    Science.gov (United States)

    Furusawa, Takaaki; Iwano, Hidetomo; Hiyashimizu, Yutaro; Matsubara, Kazuki; Higuchi, Hidetoshi; Nagahata, Hajime; Niwa, Hidekazu; Katayama, Yoshinari; Kinoshita, Yuta; Hagiwara, Katsuro; Iwasaki, Tomohito; Tanji, Yasunori; Yokota, Hiroshi; Tamura, Yutaka

    2016-09-01

    Bacterial keratitis of the horse is mainly caused by staphylococci, streptococci, and pseudomonads. Of these bacteria, Pseudomonas aeruginosa sometimes causes rapid corneal corruption and, in some cases, blindness. Antimicrobial resistance can make treatment very difficult. Therefore, new strategies to control bacterial infection are required. A bacteriophage (phage) is a virus that specifically infects and kills bacteria. Since phage often can lyse antibiotic-resistant bacteria because the killing mechanism is different, we examined the use of phage to treat horse bacterial keratitis. We isolated Myoviridae or Podoviridae phages, which together have a broad host range. They adsorb efficiently to host bacteria; more than 80% of the ΦR18 phage were adsorbed to host cells after 30 s. In our keratitis mouse model, the administration of phage within 3 h also could kill bacteria and suppress keratitis. A phage multiplicity of infection of 100 times the host bacterial number could kill host bacteria effectively. A cocktail of two phages suppressed bacteria in the keratitis model mouse. These data demonstrated that the phages in this study could completely prevent the keratitis caused by P. aeruginosa in a keratitis mouse model. Furthermore, these results suggest that phage may be a more effective prophylaxis for horse keratitis than the current preventive use of antibiotics. Such treatment may reduce the use of antibiotics and therefore antibiotic resistance. Further studies are required to assess phage therapy as a candidate for treatment of horse keratitis. Antibiotic-resistant bacteria are emerging all over the world. Bacteriophages have great potential for resolution of this problem. A bacteriophage, or phage, is a virus that infects bacteria specifically. As a novel therapeutic strategy against racehorse keratitis caused by Pseudomonas aeruginosa, we propose the application of phages for treatment. Phages isolated in this work had in vitro effectiveness for a broad

  20. Identification of operator sites of the CI repressor of phage TP901-1: evolutionary link to other phages

    International Nuclear Information System (INIS)

    Johansen, Annette H.; Broendsted, Lone; Hammer, Karin

    2003-01-01

    The repressor encoded by the cI gene of the temperate Lactococcus lactis subsp. cremoris bacteriophage TP901-1 has been purified. Gel-retardation and footprinting analyses identified three palindromic operator sites (O R , O L , and O D ). The operator site O R is located between the two divergent early promoters P R and P L , O L overlaps the transcriptional start of the lytic P L promoter, and O D is located downstream of the mor gene, the first gene in the lytic gene cluster. The function of O L was verified by mutational analysis. Binding was found to be specific and cooperative. Multimeric forms of the repressor were observed, thus indicating that the repressor may bind simultaneously to all three operator sites. Inverted repeats with homology to the operator sites of TP901-1 were identified in phage genomes encoding repressors homologous to CI of TP901-1. Interestingly, the locations of these repeats on the phage genomes correspond to those found in TP901-1, indicating that the same system of cooperative repression of early phage promoters has been inherited by modular evolution

  1. Reconstruction of 2D x-ray radiographs at the National Ignition Facility using pinhole tomography (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Field, J. E., E-mail: field9@llnl.gov; Rygg, J. R.; Barrios, M. A.; Benedetti, L. R.; Döppner, T.; Izumi, N.; Jones, O.; Khan, S. F.; Ma, T.; Nagel, S. R.; Pak, A.; Tommasini, R.; Bradley, D. K.; Town, R. P. J. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2014-11-15

    Two-dimensional radiographs of imploding fusion capsules are obtained at the National Ignition Facility by projection through a pinhole array onto a time-gated framing camera. Parallax among images in the image array makes it possible to distinguish contributions from the capsule and from the backlighter, permitting correction of backlighter non-uniformities within the capsule radiograph. Furthermore, precise determination of the imaging system geometry and implosion velocity enables combination of multiple images to reduce signal-to-noise and discover new capsule features.

  2. Computation of 2-D pinhole image-formation process of large-scale furnaces using the discrete ordinates method

    CERN Document Server

    Li Hong; Lu Ji Dong; Zheng Chu Guan

    2003-01-01

    In most of the discrete ordinate schemes (DOS) reported in the literature, the discrete directions are fixed, and unable to be arbitrarily adjusted; therefore, it is difficult to employ these schemes to calculate the radiative energy image-formation of pulverized-coal furnaces. On the basis of a new DOS, named the discrete ordinate scheme with (an) infinitely small weight(s), which was recently proposed by the authors, a novel algorithm for computing the pinhole image-formation process is developed in this work. The performance of this algorithm is tested, and is found to be also suitable for parallel computation.

  3. Computation of 2-D pinhole image-formation process of large-scale furnaces using the discrete ordinates method

    International Nuclear Information System (INIS)

    Li Hongshun; Zhou Huaichun; Lu Jidong; Zheng Chuguang

    2003-01-01

    In most of the discrete ordinate schemes (DOS) reported in the literature, the discrete directions are fixed, and unable to be arbitrarily adjusted; therefore, it is difficult to employ these schemes to calculate the radiative energy image-formation of pulverized-coal furnaces. On the basis of a new DOS, named the discrete ordinate scheme with (an) infinitely small weight(s), which was recently proposed by the authors, a novel algorithm for computing the pinhole image-formation process is developed in this work. The performance of this algorithm is tested, and is found to be also suitable for parallel computation

  4. Dynamic molecular imaging of cardiac innervation using a dual head pinhole SPECT system

    International Nuclear Information System (INIS)

    Hu, Jicun; Boutchko, Rostyslav; Sitek, Arkadiusz; Reutter, BryanW.; Huesman, Ronald H.; Gullberg, Grant T.

    2008-01-01

    Typically 123I-MIBG is used for the study of innervation and function of the sympathetic nervous system in heart failure. The protocol involves two studies: first a planar or SPECT scan is performed to measure initial uptake of the tracer, followed some 3-4 hours later by another study measuring the wash-out of the tracer from the heart. A fast wash-out is indicative of a compromised heart. In this work, a dual head pinhole SPECT system was used for imaging the distribution and kinetics of 123I-MIBG in the myocardium of spontaneous hypertensive rats (SHR) and normotensive Wistar Kyoto (WKY) rats. The system geometry was calibrated based on a nonlinear point projection fitting method using a three-point source phantom. The angle variation effect of the parameters was modeled with a sinusoidal function. A dynamic acquisition was performed by injecting 123I-MIBG into rats immediately after starting the data acquisition. The detectors rotated continuously performing a 360o data acquisition every 90 seconds. We applied the factor analysis (FA)method and region of interest (ROI) sampling method to obtain time activity curves (TACs)in the blood pool and myocardium and then applied two-compartment modeling to estimate the kinetic parameters. Since the initial injection bolus is too fast for obtaining a consistent tomographic data set in the first few minutes of the study, we applied the FA method directly to projections during the first rotation. Then the time active curves for blood and myocardial tissue were obtained from ROI sampling. The method was applied to determine if there were differences in the kinetics between SHR and WKY rats and requires less time by replacing the delayed scan at 3-4 hours after injection with a dynamic acquisition over 90 to 120 minutes. The results of a faster washout and a smaller distribution volume of 123I-MIBG near the end of life in the SHR model of hypertrophic cardiomyopthy may be indicative of a failing heart in late stages of heart

  5. [Screening serum response special antibodies of U251 cell line from surface display phage antibody library].

    Science.gov (United States)

    Yu, Min; Tan, De-Yong; Qian, Wei; Lai, Jian-Hua; Sun, Gui-Lin

    2004-05-01

    U251 cell is a sensitive cell line to serum, which stops at G0 phase of cell cycle in no-serum medium, and recovers growth when the serum is added into no-serum medium. The cell can express corresponding proteins in different phase of cell cycle. Therefore it is very signification for the study of cell cycle regulation mechanism that explores these proteins. In this paper, the mouse antibody phage display library was added into the bottle in which the serum starvation U251 cells had been cultured, and the special antibody phages were absorbed. Then the absorbed antibody phages were amplified by adding E. coli TG1 and helper phage M13K07. Amplified antibody phages were added into bottle in which the serum cultured cell after serum starvation (follow named as serum recovered cells) were incubated, so that the cell absorbed the no-special antibody phages for the serum starvation cell and the special antibody phages were in supernatant. The remaining no-special antibody phages in the supernatant were discarded by repeating above program 3-4 times. The pure special antibody phages were gotten, and amplified by adding the host cell E. coli TG1 and helper phage M13K07. Then the host bacterium infected special antibody phage was spread on the plate medium with ampicillin, and the monoclonal antibody phages were gotten. Using same as above program, the monoclonal antibody phages absorbed specially for serum recovered U251 cells were obtained when the serum recovered cells instead of serum starvation cells and serum starvation cells instead of serum recovered cells. In this study, ninety-six positive monoclonal antibody phages that absorbed specially the serum starvation cells and eighty-two positive monoclonal antibody phages that absorbed specially the serum recovered cells were obtained. By using cell immunochemistry assay, two special signification antibodies were obtained. one (No.11) was the strong response in serum starvation cells, the other (No.2) was the strong

  6. Genetic characterization of ØVC8 lytic phage for Vibrio cholerae O1.

    Science.gov (United States)

    Solís-Sánchez, Alejandro; Hernández-Chiñas, Ulises; Navarro-Ocaña, Armando; De la Mora, Javier; Xicohtencatl-Cortes, Juan; Eslava-Campos, Carlos

    2016-03-22

    Epidemics and pandemics of cholera, a diarrheal disease, are attributed to Vibrio cholera serogroups O1 and O139. In recent years, specific lytic phages of V. cholera have been proposed to be important factors in the cyclic occurrence of cholera in endemic areas. However, the role and potential participation of lytic phages during long interepidemic periods of cholera in non-endemic regions have not yet been described. The purpose of this study was to isolate and characterize specific lytic phages of V. cholera O1 strains. Sixteen phages were isolated from wastewater samples collected at the Endhó Dam in Hidalgo State, Mexico, concentrated with PEG/NaCl, and purified by density gradient. The lytic activity of the purified phages was tested using different V. cholerae O1 and O139 strains. Phage morphology was visualized by transmission electron microscopy (TEM), and phage genome sequencing was performed using the Genome Analyzer IIx System. Genome assembly and bioinformatics analysis were performed using a set of high-throughput programs. Phage structural proteins were analyzed by mass spectrometry. Sixteen phages with lytic and lysogenic activity were isolated; only phage ØVC8 showed specific lytic activity against V. cholerae O1 strains. TEM images of ØVC8 revealed a phage with a short tail and an isometric head. The ØVC8 genome comprises linear double-stranded DNA of 39,422 bp with 50.8 % G + C. Of the 48 annotated ORFs, 16 exhibit homology with sequences of known function and several conserved domains. Bioinformatics analysis showed multiple conserved domains, including an Ig domain, suggesting that ØVC8 might adhere to different mucus substrates such as the human intestinal epithelium. The results suggest that ØVC8 genome utilize the "single-stranded cohesive ends" packaging strategy of the lambda-like group. The two structural proteins sequenced and analyzed are proteins of known function. ØVC8 is a lytic phage with specific activity against V. cholerae

  7. Bacteriophage-resistant mutants in Yersinia pestis: identification of phage receptors and attenuation for mice.

    Directory of Open Access Journals (Sweden)

    Andrey A Filippov

    Full Text Available BACKGROUND: Bacteriophages specific for Yersinia pestis are routinely used for plague diagnostics and could be an alternative to antibiotics in case of drug-resistant plague. A major concern of bacteriophage therapy is the emergence of phage-resistant mutants. The use of phage cocktails can overcome this problem but only if the phages exploit different receptors. Some phage-resistant mutants lose virulence and therefore should not complicate bacteriophage therapy. METHODOLOGY/PRINCIPAL FINDINGS: The purpose of this work was to identify Y. pestis phage receptors using site-directed mutagenesis and trans-complementation and to determine potential attenuation of phage-resistant mutants for mice. Six receptors for eight phages were found in different parts of the lipopolysaccharide (LPS inner and outer core. The receptor for R phage was localized beyond the LPS core. Most spontaneous and defined phage-resistant mutants of Y. pestis were attenuated, showing increase in LD₅₀ and time to death. The loss of different LPS core biosynthesis enzymes resulted in the reduction of Y. pestis virulence and there was a correlation between the degree of core truncation and the impact on virulence. The yrbH and waaA mutants completely lost their virulence. CONCLUSIONS/SIGNIFICANCE: We identified Y. pestis receptors for eight bacteriophages. Nine phages together use at least seven different Y. pestis receptors that makes some of them promising for formulation of plague therapeutic cocktails. Most phage-resistant Y. pestis mutants become attenuated and thus should not pose a serious problem for bacteriophage therapy of plague. LPS is a critical virulence factor of Y. pestis.

  8. The use of phage FCL-2 as an alternative to chemotherapy against columnaris disease in aquaculture

    Directory of Open Access Journals (Sweden)

    Elina eLaanto

    2015-08-01

    Full Text Available Flavobacterium columnare, the causative agent of columnaris disease in fish, causes millions of dollars of losses in the US channel catfish industry alone, not to mention aquaculture industry worldwide. Novel methods are needed for the control and treatment of bacterial diseases in aquaculture to replace traditionally used chemotherapies. A potential solution could be the use of phages, i.e., bacterial viruses, host-specific and self-enriching particles that can be can easily distributed via water flow. We examined the efficacy of phages to combat columnaris disease. A previously isolated phage, FCL-2, infecting F. columnare, was characterized by sequencing. The 47 142 bp genome of the phage had G + C content of 30.2%, and the closest similarities regarding the structural proteins were found in Cellulophaga phage phiSM. Under controlled experimental conditions, two host fish species, rainbow trout (Oncorhynchus mykiss and zebrafish (Danio rerio, were used to study the success of phage therapy to prevent F. columnare infections. The survival of both fish species was significantly higher in the presence of the phage. Hundred percent of the zebrafish and 50 % of the rainbow trout survived in the phage treatment (survival without phage 0 % and 8.3 %, respectively. Most importantly, the rainbow trout population was rescued from infection by a single addition of the phage into the water in a flow-through fish tank system. Thus, F. columnare could be used as a model system to test the benefits and risks of phage therapy on a larger scale.

  9. Longitudinal monitoring of Listeria monocytogenes and Listeria phages in seafood processing environments in Thailand.

    Science.gov (United States)

    Vongkamjan, Kitiya; Benjakul, Soottawat; Kim Vu, Hue Thi; Vuddhakul, Varaporn

    2017-09-01

    Listeria monocytogenes is a foodborne pathogen commonly found in environments of seafood processing, thus presenting a challenge for eradication from seafood processing facilities. Monitoring the prevalence and subtype diversity of L. monocytogenes together with phages that are specific to Listeria spp. ("Listeria phages") will provide knowledge on the bacteria-phage ecology in food processing plants. In this work, a total of 595 samples were collected from raw material, finished seafood products and environmental samples from different sites of a seafood processing plant during 17 sampling visits in 1.5 years of study. L. monocytogenes and Listeria spp. (non-monocytogenes) were found in 22 (3.7%) and 43 (7.2%) samples, respectively, whereas 29 Listeria phages were isolated from 9 (1.5%) phage-positive samples. DNA fingerprint analysis of L. monocytogenes isolates revealed 11 Random Amplified Polymorphic DNA (RAPD) profiles, with two subtypes were frequently observed over time. Our data reveal a presence of Listeria phages within the same seafood processing environments where a diverse set of L. monocytogenes subtypes was also found. Although serotype 4b was observed at lower frequency, data indicate that isolates from this seafood processing plant belonged to both epidemiologically important serotypes 1/2a and 4b, which may suggest a potential public health risk. Phages (all showed a unique genome size of 65 ± 2 kb) were classified into 9 host range groups, representing both broad- and narrow-host range. While most L. monocytogenes isolates from this facility were susceptible to phages, five isolates showed resistance to 12-20 phages. Variations in phage host range among Listeria phages isolated from food processing plant may affect a presence of a diverse set of L. monocytogenes isolates derived from the same processing environment in Thailand. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Analysis of high-throughput sequencing and annotation strategies for phage genomes.

    Directory of Open Access Journals (Sweden)

    Matthew R Henn

    Full Text Available BACKGROUND: Bacterial viruses (phages play a critical role in shaping microbial populations as they influence both host mortality and horizontal gene transfer. As such, they have a significant impact on local and global ecosystem function and human health. Despite their importance, little is known about the genomic diversity harbored in phages, as methods to capture complete phage genomes have been hampered by the lack of knowledge about the target genomes, and difficulties in generating sufficient quantities of genomic DNA for sequencing. Of the approximately 550 phage genomes currently available in the public domain, fewer than 5% are marine phage. METHODOLOGY/PRINCIPAL FINDINGS: To advance the study of phage biology through comparative genomic approaches we used marine cyanophage as a model system. We compared DNA preparation methodologies (DNA extraction directly from either phage lysates or CsCl purified phage particles, and sequencing strategies that utilize either Sanger sequencing of a linker amplification shotgun library (LASL or of a whole genome shotgun library (WGSL, or 454 pyrosequencing methods. We demonstrate that genomic DNA sample preparation directly from a phage lysate, combined with 454 pyrosequencing, is best suited for phage genome sequencing at scale, as this method is capable of capturing complete continuous genomes with high accuracy. In addition, we describe an automated annotation informatics pipeline that delivers high-quality annotation and yields few false positives and negatives in ORF calling. CONCLUSIONS/SIGNIFICANCE: These DNA preparation, sequencing and annotation strategies enable a high-throughput approach to the burgeoning field of phage genomics.

  11. Genomic Characterization of a Novel Phage Found in Black Abalone (Haliotis cracherodii) Infected with Withering Syndrome

    Science.gov (United States)

    Closek, C. J.; Langevin, S.; Burge, C. A.; Crosson, L.; White, S.; Friedman, C. S.

    2016-02-01

    Withering syndrome (WS), caused by the bacterium Candidatus Xenohaliotis californiensis, a Rickettsia-like organism (RLO), infects many species of abalone. Black abalone (Haliotis cracherodii), one of two endangered species of abalone, has experienced high population losses along the California coast due to WS. Recently, we observed reduced pathogenicity and mortality events in RLO-infected abalone when a novel bacteriophage (phage) was also present. To better understand phage-bacterium dynamics and develop more informative diagnostic tools, we sequenced the genome of the novel phage associated with the RLO responsible for WS. Metagenomic sequencing libraries were prepared with extracted genomic DNA from two experimentally infected H. cracherodii and phage sequences were enriched using hydroxyapatite chromatography normalization. Normalized libraries were individually barcoded and sequenced with Illumina MiSeq. Raw sequence reads were processed using VIrominer and de novo assembly produced one single phage-like contig (35.7Kb) from the experimentally infected abalone. This highly divergent genome had closest homology with a virus associated with abalone shriveling syndrome (SS). Of the 34 predicted ORFs, overlapping homology with the SS virus ranged from 20-72%, demonstrating the phage sequenced is genetically distinct from any known phage. The phage-like sequences represented a significant portion of the total reads sequenced ( 2 million of the 12 million paired-end reads; 17%) and we obtained 94,000X coverage across the novel phage genome. Beyond characterization of this novel phage, which appears to reduce pathogenicity of the RLO, the genome enabled us to develop quantitative PCR and in situ hybridization assays as diagnostic tools. These tools allow us to detect and quantify this phage in the endangered H. cracherodii.

  12. Novel chitosan film embedded with liposome-encapsulated phage for biocontrol of Escherichia coli O157:H7 in beef.

    Science.gov (United States)

    Cui, Haiying; Yuan, Lu; Lin, Lin

    2017-12-01

    In recent years, phages used for the reduction of pathogenic bacteria have fostered many attentions, but they are liable to lost bioactivity in food due to the presence of acidic compounds, enzymes and evaporite materials. To improve the stability of phages, a chitosan edible film containing liposome-encapsulated phage was engineered in the present study. The characteristics of liposome-encapsulated phage and the chitosan film containing liposome-encapsulated phage were investigated. The encapsulation efficiency of phages in liposome reached 57.66±0.12%. Besides, the desirable physical properties of chitosan film were obtained. The chitosan film embedded with liposome-encapsulated phage exhibited high antibacterial activity against Escherichia coli O157:H7, without the impact on the sensory properties of beef. Hence, chitosan film containing liposome-encapsulated phage could be a promising antibacterial packaging for beef preservation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Comparative genomics and functional analysis of the 936 group of lactococcal Siphoviridae phages

    NARCIS (Netherlands)

    Murphy, James; Bottacini, Francesca; Mahony, Jennifer; Kelleher, Philip; Neve, Horst; Zomer, Aldert; Nauta, Arjen; van Sinderen, Douwe

    2016-01-01

    Genome sequencing and comparative analysis of bacteriophage collections has greatly enhanced our understanding regarding their prevalence, phage-host interactions as well as the overall biodiversity of their genomes. This knowledge is very relevant to phages infecting Lactococcus lactis, since they

  14. Treatment of in vitro enterohemorrhagic Escherichia coli infection using phage and probiotics.

    Science.gov (United States)

    Dini, C; Bolla, P A; de Urraza, P J

    2016-07-01

    To assay the combination of phage and probiotics against EHEC in vitro on infected Hep-2 cells. Phage and probiotics treatments on EHEC O157:H7-infected Hep-2 cells were assayed individually or combined. The effect of freeze-drying on phage and probiotic antimicrobial activity was also studied. While treatment with phage alone increased cell detachment caused by EHEC infection, the treatments with MM alone or in combination with phage proved to effectively diminish cell damage caused by EHEC infection. Combined treatment showed a decrease in apoptotic cell count of 57·3% and a reduction in EHEC adhesion to cell monolayer of 1·2 log CFU. The simultaneous use of phage and probiotics showed no antagonistic effect, and freeze-drying did not affect their antipathogenic activity. The combination of phage and probiotics has great potential for reducing the number of pathogens adhered to epithelial cells during EHEC O157:H7 infection and attenuating the cytotoxic effect derived from it. Further in vivo assays are needed for assessing the actual effectiveness of the treatment. This study presents a freeze-dried formulation of phage and probiotics capable of controlling EHEC infections and reducing epithelial cell damage in vitro. © 2016 The Society for Applied Microbiology.

  15. Lytic phages obscure the cost of antibiotic resistance in Escherichia coli.

    Science.gov (United States)

    Tazzyman, Samuel J; Hall, Alex R

    2015-03-17

    The long-term persistence of antibiotic-resistant bacteria depends on their fitness relative to other genotypes in the absence of drugs. Outside the laboratory, viruses that parasitize bacteria (phages) are ubiquitous, but costs of antibiotic resistance are typically studied in phage-free experimental conditions. We used a mathematical model and experiments with Escherichia coli to show that lytic phages strongly affect the incidence of antibiotic resistance in drug-free conditions. Under phage parasitism, the likelihood that antibiotic-resistant genetic backgrounds spread depends on their initial frequency, mutation rate and intrinsic growth rate relative to drug-susceptible genotypes, because these parameters determine relative rates of phage-resistance evolution on different genetic backgrounds. Moreover, the average cost of antibiotic resistance in terms of intrinsic growth in the antibiotic-free experimental environment was small relative to the benefits of an increased mutation rate in the presence of phages. This is consistent with our theoretical work indicating that, under phage selection, typical costs of antibiotic resistance can be outweighed by realistic increases in mutability if drug resistance and hypermutability are genetically linked, as is frequently observed in clinical isolates. This suggests the long-term distribution of antibiotic resistance depends on the relative rates at which different lineages adapt to other types of selection, which in the case of phage parasitism is probably extremely common, as well as costs of resistance inferred by classical in vitro methods.

  16. Phage FR38 Treatment on Sprague Dawley Rat Inferred from Blood Parameters and Organ Systems

    Directory of Open Access Journals (Sweden)

    DEWI SARTIKA

    2012-09-01

    Full Text Available The ability of phage FR38 to lysis indigenous Salmonella P38 from feces of diarrheal patient has been studied. However, effects of phage FR38 on organ system were not revealed as yet. This study was conducted to observe the effect of phage FR38 on blood chemistry, kidney functions, and liver functions. Twelve Sprague-Dawley rats were used as a model for this study that were divided into two groups; (i control and (ii treated group with phage FR38. For treated phage group, each rat was administered by 5 ml/kg bw of 1.59•107 pfu/ml of phage intragastric. The blood parameters were analysed on day 16. The results revealed that body and organs weight, erythrocyte, hematocrit, hemoglobin, leukocyte, total protein, creatinine, SGOT, and SGPT of phage treatment rats were not significantly different with the control rats on day 16 (P > 0.05. Therefore, this study showed was no effect of phage FR38 on body weight, blood chemistry, kidney and liver functions of the rat (P > 0.05.

  17. Phage FR38 Treatment on Sprague Dawley Rat Inferred from Blood Parameters and Organ Systems

    Directory of Open Access Journals (Sweden)

    DEWI SARTIKA

    2012-09-01

    Full Text Available The ability of phage FR38 to lysis indigenous Salmonella P38 from feces of diarrheal patient has been studied. However, effects of phage FR38 on organ system were not revealed as yet. This study was conducted to observe the effect of phage FR38 on blood chemistry, kidney functions, and liver functions. Twelve Sprague-Dawley rats were used as a model for this study that were divided into two groups; (i control and (ii treated group with phage FR38. For treated phage group, each rat was administered by 5 ml/kg bw of 1.59-107 pfu/ml of phage intragastric. The blood parameters were analysed on day 16. The results revealed that body and organs weight, erythrocyte, hematocrit, hemoglobin, leukocyte, total protein, creatinine, SGOT, and SGPT of phage treatment rats were not significantly different with the control rats on day 16 (P > 0.05. Therefore, this study showed was no effect of phage FR38 on body weight, blood chemistry, kidney and liver functions of the rat (P > 0.05.

  18. Bioinformatic analysis of phage AB3, a phiKMV-like virus infecting Acinetobacter baumannii.

    Science.gov (United States)

    Zhang, J; Liu, X; Li, X-J

    2015-01-16

    The phages of Acinetobacter baumannii has drawn increasing attention because of the multi-drug resistance of A. baumanni. The aim of this study was to sequence Acinetobacter baumannii phage AB3 and conduct bioinformatic analysis to lay a foundation for genome remodeling and phage therapy. We isolated and sequenced A. baumannii phage AB3 and attempted to annotate and analyze its genome. The results showed that the genome is a double-stranded DNA with a total length of 31,185 base pairs (bp) and 97 open reading frames greater than 100 bp. The genome includes 28 predicted genes, of which 24 are homologous to phage AB1. The entire coding sequence is located on the negative strand, representing 90.8% of the total length. The G+C mol% was 39.18%, without areas of high G+C content over 200 bp in length. No GC island, tRNA gene, or repeated sequence was identified. Gene lengths were 120-3099 bp, with an average of 1011 bp. Six genes were found to be greater than 2000 bp in length. Genomic alignment and phylogenetic analysis of the RNA polymerase gene showed that similar to phage AB1, phage AB3 is a phiKMV-like virus in the T7 phage family.

  19. Detection of sulfur mustard adducts in human callus by phage antibodies

    NARCIS (Netherlands)

    Bikker, F.J.; Mars-Groenendijk, R.H.; Noort, D.; Fidder, A.; Schans, G.P. van der

    2007-01-01

    As part of a research program to develop novel methods for diagnosis of sulfur mustard exposure in the human skin the suitability of phage display was explored. Phage display is a relative new method that enables researchers to quickly evaluate a huge range of potentially useful antibodies, thereby

  20. Survey on the phage resistance mechanisms displayed by a dairy Lactobacillus helveticus strain.

    Science.gov (United States)

    Zago, Miriam; Orrù, Luigi; Rossetti, Lia; Lamontanara, Antonella; Fornasari, Maria Emanuela; Bonvini, Barbara; Meucci, Aurora; Carminati, Domenico; Cattivelli, Luigi; Giraffa, Giorgio

    2017-09-01

    In this study the presence and functionality of phage defence mechanisms in Lactobacillus helveticus ATCC 10386, a strain of dairy origin which is sensitive to ΦLh56, were investigated. After exposure of ATCC 10386 to ΦLh56, the whole-genome sequences of ATCC 10386 and of a phage-resistant derivative (LhM3) were compared. LhM3 showed deletions in the S-layer protein and a higher expression of the genes involved in the restriction/modification (R/M) system. Genetic data were substantiated by measurements of bacteriophage adsorption rates, efficiency of plaquing, cell wall protein size and by gene expression analysis. In LhM3 two phage resistance mechanisms, the inhibition of phage adsorption and the upregulation of Type I R/M genes, take place and explain its resistance to ΦLh56. Although present in both ATCC 10386 and LhM3 genomes, the CRISPR machinery did not seem to play a role in the phage resistance of LhM3. Overall, the natural selection of phage resistant strains resulted successful in detecting variants carrying multiple phage defence mechanisms in L. helveticus. The concurrent presence of multiple phage-resistance systems should provide starter strains with increased fitness and robustness in dairy ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Metagenomic Analysis of Therapeutic PYO Phage Cocktails from 1997 to 2014

    DEFF Research Database (Denmark)

    Villarroel, Julia; Larsen, Mette Voldby; Kilstrup, Mogens

    2017-01-01

    in the two cocktails. One of these showed no similarity to publicly available phage genomes. Representatives of phages targeting E. faecalis, E. faecium, E. coli, Proteus, P. aeruginosa and S. aureus were found in both cocktails. Finally, we estimated larger overlap of the PYO2000 cocktail to PYO97 compared...

  2. Vibrio Phage KVP40 Encodes a Functional NAD+ Salvage Pathway.

    Science.gov (United States)

    Lee, Jae Yun; Li, Zhiqun; Miller, Eric S

    2017-05-01

    + for ADP-ribosylation of proteins involved in transcribing and translating the phage genome. We show here that phage KVP40 encodes a functional pyridine nucleotide scavenging pathway that is expressed during the metabolic period of the infection cycle. The pathway is conserved in other large, dsDNA phages in which the two genes, nadV and natV , share an evolutionary history in their respective phage-host group. Copyright © 2017 American Society for Microbiology.

  3. SNP-PHAGE – High throughput SNP discovery pipeline

    Directory of Open Access Journals (Sweden)

    Cregan Perry B

    2006-10-01

    Full Text Available Abstract Background Single nucleotide polymorphisms (SNPs as defined here are single base sequence changes or short insertion/deletions between or within individuals of a given species. As a result of their abundance and the availability of high throughput analysis technologies SNP markers have begun to replace other traditional markers such as restriction fragment length polymorphisms (RFLPs, amplified fragment length polymorphisms (AFLPs and simple sequence repeats (SSRs or microsatellite markers for fine mapping and association studies in several species. For SNP discovery from chromatogram data, several bioinformatics programs have to be combined to generate an analysis pipeline. Results have to be stored in a relational database to facilitate interrogation through queries or to generate data for further analyses such as determination of linkage disequilibrium and identification of common haplotypes. Although these tasks are routinely performed by several groups, an integrated open source SNP discovery pipeline that can be easily adapted by new groups interested in SNP marker development is currently unavailable. Results We developed SNP-PHAGE (SNP discovery Pipeline with additional features for identification of common haplotypes within a sequence tagged site (Haplotype Analysis and GenBank (-dbSNP submissions. This tool was applied for analyzing sequence traces from diverse soybean genotypes to discover over 10,000 SNPs. This package was developed on UNIX/Linux platform, written in Perl and uses a MySQL database. Scripts to generate a user-friendly web interface are also provided with common queries for preliminary data analysis. A machine learning tool developed by this group for increasing the efficiency of SNP discovery is integrated as a part of this package as an optional feature. The SNP-PHAGE package is being made available open source at http://bfgl.anri.barc.usda.gov/ML/snp-phage/. Conclusion SNP-PHAGE provides a bioinformatics

  4. Lethal congenital contracture syndrome (LCCS) and other lethal arthrogryposes in Finland--an epidemiological study.

    Science.gov (United States)

    Pakkasjärvi, Niklas; Ritvanen, Annukka; Herva, Riitta; Peltonen, Leena; Kestilä, Marjo; Ignatius, Jaakko

    2006-09-01

    Arthrogryposis multiplex congenita is a heterogeneous group of disorders characterized by multiple contractures with an estimated frequency of 1 in 3,000 births. With improving diagnostic methods, increasing numbers of fetuses with arthrogryposis are found. The pathogenetic mechanisms are relatively well known but the epidemiology and genetics of the prenatally lethal forms of arthrogryposis are less well known. In this study we collected all cases of a multiple contractures diagnosed in Finland during 1987-2002 including live born infants, stillbirths, and terminated pregnancies. Ninety-two cases of 214 suffered intrauterine demise (68 selective pregnancy terminations and 24 stillbirths) and 58 died in infancy. In 141 out of these cases the diagnosis could be included within lethal arthrogryposes, with a prevalence of 1 in 6,985 (1.43/10,000) births. Of these, 59 had spinal cord pathology at autopsy and thus were of neurogenic origin. Thirty-nine cases had lethal congenital contracture syndrome (LCCS) clinically characterized by total immobility of the fetus at all ultrasound examinations (12 weeks or later), multiple joint contractures in both upper and lower limbs, hydrops, and fetal death before the 32nd week of pregnancy. LCCS is noted as a unique Finnish disorder with a prevalence of 1 in 25,250 (0.40/10,000) births and is a major cause of lethal arthrogryposis in Finland.

  5. Suicide Intent and Accurate Expectations of Lethality: Predictors of Medical Lethality of Suicide Attempts

    Science.gov (United States)

    Brown, Gregory K.; Henriques, Gregg R.; Sosdjan, Daniella; Beck, Aaron T.

    2004-01-01

    The degree of intent to commit suicide and the severity of self-injury were examined in individuals (N = 180) who had recently attempted suicide. Although a minimal association was found between the degree of suicide intent and the degree of lethality of the attempt, the accuracy of expectations about the likelihood of dying was found to moderate…

  6. Potentially lethal damage and its repair

    International Nuclear Information System (INIS)

    Utsumi, Hiroshi

    1989-01-01

    Two forms termed fast-and slow-potentially lethal lethal damage (PLD) are introduced and discussed. The effect on the survival of x-irradiated Chinese hamster cells (V79) of two different post-treatments is examined in plateau- and in log-phases of growth. The postirradiation treatments used : a) incubation in hypertonic solution, and b) incubation in conditioned medium obtained from plateau-phase. Similar reduction in survival was caused by postirradiation treatment with hypertonic phosphate buffered saline, and similar increased in survival was effected by treatment in conditioned medium in plateau- and in log-phases cells. However, repair of PLD sensitive to hypertonic treatment was faster (half time, 5-10 min)(f-PLD repair) and independent from the repair of PLD (half time, 1-2 hour)(s-PLD repair) observed in conditioned medium. The results indicate the induction of two forms of PLD by radiation. Induction of both PLD was found to decrease with increasing LET of the radiation used. Identification of the molecular processes underlying repair and fixation of PLD is a task of particular interest, since it may allow replacement of a phenomenological definition with a molecular definition. Evidence is reviewed indicating the DNA double strand breaks (directly or indirectly induced) may be the DNA lesions underlying PLD. (author)

  7. Assessment of the Effects of Various UV Sources on Inactivation and Photoproduct Induction in Phage T7 Dosimeter

    NARCIS (Netherlands)

    Fekete, A.; Vink, A.A.; Gaspar, S.; Berces, A.; Modos, K.; Ronto, Gy.; Roza, L.

    1998-01-01

    The correlation between the biologically effective dose (BED) of a phage T7 biological dosimeter and the induction of cyclobutane pyrimidine dimers (CPD) and (6-4) photoproducts ((6-4)PD) in the phage DNA was determined using seven various UV sources. The BED is the inactivation rate of phage T7

  8. Lethal domestic violence in eastern North Carolina.

    Science.gov (United States)

    Gilliland, M G; Spence, P R; Spence, R L

    2000-01-01

    Strategies for preventing domestic violence can be tailored to a particular geographic or socioeconomic area if the patterns of domestic violence in the area are known. National statistics, although widely available, may not be applicable to a specific region. We reviewed homicide deaths in Eastern North Carolina between 1978 and 1999 to identify patterns in this rural area. Approximately 20% of the homicide deaths in eastern North Carolina are caused by intimate partners. Women accounted for 53% of the victims in 1976, similar to national figures but not rising to 72% as seen nationally in 1998. Latinos are an increasing presence in the area, but had only one recorded episode of lethal violence against an intimate partner. Gunshots accounted for most of the deaths (59% in men, 72% in women). Knowledge of such patterns can assist in selecting prevention strategies for this particular area. Over the last 25 years increasing attention has been devoted to domestic violence (DV), initially defined as abuse committed against a spouse, former spouse, fiancée, boy- or girlfriend, or cohabitant. As time has passed, the definition has been broadened to include other family members--elders, children, and siblings. The Centers for Disease Control and Prevention (CDC) now uses the term "intimate partner violence" for intentional emotional or physical abuse inflicted by a spouse, ex-spouse, a present or former boy- or girlfriend, or date. For the purposes of this paper, we consider DV interchangeable with intimate partner violence. There has been a national concern that abusive events are under-reported. The National Crime Victimization Survey, an anonymous household survey, indicated nearly 1 million incidents of non-lethal intimate partner violence per year between 1992 and 1996. The number decreased from 1.1 million in 1993 to 840,000 in 1996. Attempts to validate such data for a given geographic area often require subjects to violate anonymity--this may account for lower

  9. Improved Fab presentation on phage surface with the use of molecular chaperone coplasmid system.

    Science.gov (United States)

    Loh, Qiuting; Leong, Siew Wen; Tye, Gee Jun; Choong, Yee Siew; Lim, Theam Soon

    2015-05-15

    The low presentation efficiency of Fab (fragment antigen binding) fragments during phage display is largely due to the complexity of disulphide bond formation. This can result in the presentation of Fab fragments devoid of a light chain during phage display. Here we propose the use of a coplasmid system encoding several molecular chaperones (DsbA, DsbC, FkpA, and SurA) to improve Fab packaging. A comparison was done using the Fab fragment from IgG and IgD. We found that the use of the coplasmid during phage packaging was able to improve the presentation efficiency of the Fab fragment on phage surfaces. A modified version of panning using the coplasmid system was evaluated and was successful at enriching Fab binders. Therefore, the coplasmid system would be an attractive alternative for improved Fab presentation for phage display. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Phage based green chemistry for gold ion reduction and gold retrieval.

    Science.gov (United States)

    Setyawati, Magdiel I; Xie, Jianping; Leong, David T

    2014-01-22

    The gold mining industry has taken its toll on the environment, triggering the development of more environmentally benign processes to alleviate the waste load release. Here, we demonstrate the use of bacteriophages (phages) for biosorption and bioreduction of gold ions from aqueous solution, which potentially can be applied to remediate gold ions from gold mining waste effluent. Phage has shown a remarkably efficient sorption of gold ions with a maximum gold adsorption capacity of 571 mg gold/g dry weight phage. The product of this phage mediated process is gold nanocrystals with the size of 30-630 nm. Biosorption and bioreduction processes are mediated by the ionic and covalent interaction between gold ions and the reducing groups on the phage protein coat. The strategy offers a simple, ecofriendly and feasible option to recover of gold ions to form readily recoverable products of gold nanoparticles within 24 h.

  11. Association between phage types and antimicrobial resistance among bovine isolates of Staphylococcus aureus in 10 countries

    DEFF Research Database (Denmark)

    Vintov, J.; Aarestrup, Frank Møller; Zinn, C. E.

    2003-01-01

    This study was conducted to investigate the diversity of phage types and associations between penicillin resistance and phage types among 815 Staphylococcus aureus isolates from bovine mastitis in nine European countries and USA. All isolates were examined for susceptibility to antimicrobial agents...... associated with penicillin resistance in contrast to phage group I (P = 0.0023) and phage complex-80 (P = 0.0066). This study confirms that a large number of phage types of S. aureus cause bovine mastitis, but that some types predominate. In addition, these findings could indicate that the use of penicillin...... in the bovine environment has selected for specific types of S. aureus in countries with a high frequency of resistance. (C) 2003 Elsevier B.V. All rights reserved....

  12. Association between phage types and antimicrobial resistance among bovine Staphylococcus aureus from 10 countries

    DEFF Research Database (Denmark)

    Vintov, J.; Aarestrup, Frank Møller; Zinn, C. E.

    2003-01-01

    This study was conducted to investigate the diversity of phage types and associations between penicillin resistance and phage types among 815 Staphylococcus aureus isolates from bovine mastitis in nine European countries and USA. All isolates were examined for susceptibility to antimicrobial agents...... associated with penicillin resistance in contrast to phage group I (P = 0.0023) and phage complex-80 (P = 0.0066). This study confirms that a large number of phage types of S. aureus cause bovine mastitis, but that some types predominate. In addition, these findings could indicate that the use of penicillin...... in the bovine environment has selected for specific types of S. aureus in countries with a high frequency of resistance....

  13. A study of Salmonella typhi isolated in Suez Canal area. Biotyping, phage typing and colicinogenic property.

    Science.gov (United States)

    Shoeb, S; Khalifa, I; el Daly, O; Heiba, A; Farmer, J; Brenner, F; el Batawi, Y

    1989-01-01

    In this work a total of 82 strains of Salmonella typhi were isolated from Egyptian patients diagnosed as quiry enteric fever. These cases were from Ismalia, Suez and port Said Areas. The strains fell in 16 phage types. Phage types N, 40, E1, and degraded Vi were the commonest phage type in Ismailia, while phage types degraded Vi and C1 were the commonest in Port Said. Phage types Di-N, degraded Vi, A and C1 were the commonest in Suez. Chemotyping of Salmonella typhi showed that the majority of the strains belonged to chemotype I (82%), and the rest belonged to chemotype II (18%). Colicin production was negative and all the strains were susceptible to the currently used antibiotics.

  14. Interaction of the phage-xanthomonas campestris (Pammel) Dowson at the eletronic microscopy level, Virazole effect and radioautographic study of the phage action on the host

    International Nuclear Information System (INIS)

    Sittolin, I.M.

    1982-04-01

    A bacteriophage from the cabbage tissue infected with Xanthomonas campestris is described. The infection process is studied through a negative staining technique (PTA) and ultrathin section. The effect of Virazole, an antivirus agent, is tested. Radioautography showed that the phage presented a reasonable domain on the bacterial host genome since the beginning of the treatment. Sorological reactions indicated the induction of specific antibodies for the phage. (M.A.C.) [pt

  15. Characterization of novel virulent broad-host-range phages of Xylella fastidiosa and Xanthomonas.

    Science.gov (United States)

    Ahern, Stephen J; Das, Mayukh; Bhowmick, Tushar Suvra; Young, Ry; Gonzalez, Carlos F

    2014-01-01

    The xylem-limited bacterium Xylella fastidiosa is the causal agent of several plant diseases, most notably Pierce's disease of grape and citrus variegated chlorosis. We report the isolation and characterization of the first virulent phages for X. fastidiosa, siphophages Sano and Salvo and podophages Prado and Paz, with a host range that includes Xanthomonas spp. Phages propagated on homologous hosts had observed adsorption rate constants of ~4 × 10(-12) ml cell(-1) min(-1) for X. fastidiosa strain Temecula 1 and ~5 × 10(-10) to 7 × 10(-10) ml cell(-1) min(-1) for Xanthomonas strain EC-12. Sano and Salvo exhibit >80% nucleotide identity to each other in aligned regions and are syntenic to phage BcepNazgul. We propose that phage BcepNazgul is the founding member of a novel phage type, to which Sano and Salvo belong. The lysis genes of the Nazgul-like phage type include a gene that encodes an outer membrane lipoprotein endolysin and also spanin gene families that provide insight into the evolution of the lysis pathway for phages of Gram-negative hosts. Prado and Paz, although exhibiting no significant DNA homology to each other, are new members of the phiKMV-like phage type, based on the position of the single-subunit RNA polymerase gene. The four phages are type IV pilus dependent for infection of both X. fastidiosa and Xanthomonas. The phages may be useful as agents for an effective and environmentally responsible strategy for the control of diseases caused by X. fastidiosa.

  16. Manipulating or superseding host recombination functions: a dilemma that shapes phage evolvability.

    Directory of Open Access Journals (Sweden)

    Louis-Marie Bobay

    Full Text Available Phages, like many parasites, tend to have small genomes and may encode autonomous functions or manipulate those of their hosts'. Recombination functions are essential for phage replication and diversification. They are also nearly ubiquitous in bacteria. The E. coli genome encodes many copies of an octamer (Chi motif that upon recognition by RecBCD favors repair of double strand breaks by homologous recombination. This might allow self from non-self discrimination because RecBCD degrades DNA lacking Chi. Bacteriophage Lambda, an E. coli parasite, lacks Chi motifs, but escapes degradation by inhibiting RecBCD and encoding its own autonomous recombination machinery. We found that only half of 275 lambdoid genomes encode recombinases, the remaining relying on the host's machinery. Unexpectedly, we found that some lambdoid phages contain extremely high numbers of Chi motifs concentrated between the phage origin of replication and the packaging site. This suggests a tight association between replication, packaging and RecBCD-mediated recombination in these phages. Indeed, phages lacking recombinases strongly over-represent Chi motifs. Conversely, phages encoding recombinases and inhibiting host recombination machinery select for the absence of Chi motifs. Host and phage recombinases use different mechanisms and the latter are more tolerant to sequence divergence. Accordingly, we show that phages encoding their own recombination machinery have more mosaic genomes resulting from recent recombination events and have more diverse gene repertoires, i.e. larger pan genomes. We discuss the costs and benefits of superseding or manipulating host recombination functions and how this decision shapes phage genome structure and evolvability.

  17. Dualities in the analysis of phage DNA packaging motors

    Science.gov (United States)

    Serwer, Philip; Jiang, Wen

    2012-01-01

    The DNA packaging motors of double-stranded DNA phages are models for analysis of all multi-molecular motors and for analysis of several fundamental aspects of biology, including early evolution, relationship of in vivo to in vitro biochemistry and targets for anti-virals. Work on phage DNA packaging motors both has produced and is producing dualities in the interpretation of data obtained by use of both traditional techniques and the more recently developed procedures of single-molecule analysis. The dualities include (1) reductive vs. accretive evolution, (2) rotation vs. stasis of sub-assemblies of the motor, (3) thermal ratcheting vs. power stroking in generating force, (4) complete motor vs. spark plug role for the packaging ATPase, (5) use of previously isolated vs. new intermediates for analysis of the intermediate states of the motor and (6) a motor with one cycle vs. a motor with two cycles. We provide background for these dualities, some of which are under-emphasized in the literature. We suggest directions for future research. PMID:23532204

  18. Criteria for Selecting Suitable Infectious Diseases for Phage Therapy.

    Science.gov (United States)

    Harper, David R

    2018-04-05

    One of the main issues with phage therapy from its earliest days has been the selection of appropriate disease targets. In early work, when the nature of bacteriophages was unknown, many inappropriate targets were selected, including some now known to have no bacterial involvement whatsoever. More recently, with greatly increased understanding of the highly specific nature of bacteriophages and of their mechanisms of action, it has been possible to select indications with an increased chance of a successful therapeutic outcome. The factors to be considered include the characteristics of the infection to be treated, the characteristics of the bacteria involved, and the characteristics of the bacteriophages themselves. At a later stage all of this information then informs trial design and regulatory considerations. Where the work is undertaken towards the development of a commercial product it is also necessary to consider the planned market, protection of intellectual property, and the sourcing of funding to support the work. It is clear that bacteriophages are not a "magic bullet". However, with careful and appropriate selection of a limited set of initial targets, it should be possible to obtain proof of concept for the many elements required for the success of phage therapy. In time, success with these initial targets could then support more widespread use.

  19. Criteria for Selecting Suitable Infectious Diseases for Phage Therapy

    Directory of Open Access Journals (Sweden)

    David R. Harper

    2018-04-01

    Full Text Available One of the main issues with phage therapy from its earliest days has been the selection of appropriate disease targets. In early work, when the nature of bacteriophages was unknown, many inappropriate targets were selected, including some now known to have no bacterial involvement whatsoever. More recently, with greatly increased understanding of the highly specific nature of bacteriophages and of their mechanisms of action, it has been possible to select indications with an increased chance of a successful therapeutic outcome. The factors to be considered include the characteristics of the infection to be treated, the characteristics of the bacteria involved, and the characteristics of the bacteriophages themselves. At a later stage all of this information then informs trial design and regulatory considerations. Where the work is undertaken towards the development of a commercial product it is also necessary to consider the planned market, protection of intellectual property, and the sourcing of funding to support the work. It is clear that bacteriophages are not a “magic bullet”. However, with careful and appropriate selection of a limited set of initial targets, it should be possible to obtain proof of concept for the many elements required for the success of phage therapy. In time, success with these initial targets could then support more widespread use.

  20. In vitro incorporation of the phage Phi29 connector complex

    International Nuclear Information System (INIS)

    Fu Chiyu; Prevelige, Peter E.

    2009-01-01

    The incorporation of the DNA packaging connector complex during lambdoid phage assembly in vivo is strictly controlled-one and only one of the twelve identical icosahedral vertices is differentiated by the inclusion of a portal or connector dodecamer. Proposed control mechanisms include obligate nucleation from a connector containing complex, addition of the connector as the final step during assembly, and a connector-mediated increase in the growth rate. The inability to recapitulate connector incorporation in vitro has made it difficult to obtain direct biochemical evidence in support of one model over another. Here we report the development an in vitro assembly system for the well characterized dsDNA phage Phi29 which results in the co-assembly of connector with capsid and scaffolding proteins to form procapsid-like particles (PLPs). Immuno-electron microscopy demonstrates the specific incorporation of connector vertex in PLPs. The connector protein increases both the yield and the rate of capsid assembly suggesting that the incorporation of the connector in Phi29 likely promotes nucleation of assembly.

  1. Structural Conservation of the Myoviridae Phage Tail Sheath Protein Fold

    Energy Technology Data Exchange (ETDEWEB)

    Aksyuk, Anastasia A.; Kurochkina, Lidia P.; Fokine, Andrei; Forouhar, Farhad; Mesyanzhinov, Vadim V.; Tong, Liang; Rossmann, Michael G. (SOIBC); (Purdue); (Columbia)

    2012-02-21

    Bacteriophage phiKZ is a giant phage that infects Pseudomonas aeruginosa, a human pathogen. The phiKZ virion consists of a 1450 {angstrom} diameter icosahedral head and a 2000 {angstrom}-long contractile tail. The structure of the whole virus was previously reported, showing that its tail organization in the extended state is similar to the well-studied Myovirus bacteriophage T4 tail. The crystal structure of a tail sheath protein fragment of phiKZ was determined to 2.4 {angstrom} resolution. Furthermore, crystal structures of two prophage tail sheath proteins were determined to 1.9 and 3.3 {angstrom} resolution. Despite low sequence identity between these proteins, all of these structures have a similar fold. The crystal structure of the phiKZ tail sheath protein has been fitted into cryo-electron-microscopy reconstructions of the extended tail sheath and of a polysheath. The structural rearrangement of the phiKZ tail sheath contraction was found to be similar to that of phage T4.

  2. Epifluorescence and atomic force microscopy: Two innovative applications for studying phage-host interactions in Lactobacillus helveticus.

    Science.gov (United States)

    Zago, Miriam; Scaltriti, Erika; Fornasari, Maria Emanuela; Rivetti, Claudio; Grolli, Stefano; Giraffa, Giorgio; Ramoni, Roberto; Carminati, Domenico

    2012-01-01

    Bacteriophages attacking lactic acid bacteria (LAB) still represent a crucial problem in industrial dairy fermentations. The consequences of a phage infection against LAB can lead to fermentation delay, alteration of the product quality and, in most severe cases, the product loss. Phage particles enumeration and phage-host interactions are normally evaluated by conventional plaque count assays, but, in many cases, these methods can be unsuccessful. Bacteriophages of Lactobacillus helveticus, a LAB species widely used as dairy starter or probiotic cultures, are often unable to form lysis plaques, thus impairing their enumeration by plate assay. In this study, we used epifluorescence microscopy to enumerate L. helveticus phage particles from phage-infected cultures and Atomic Force Microscopy (AFM) to visualize both phages and bacteria during the different stages of the lytic cycle. Preliminary, we tested the sensitivity of phage counting by epifluorescence microscopy. To this end, phage particles of ΦAQ113, a lytic phage of L. helveticus isolated from a whey starter culture, were stained by SYBR Green I and enumerated by epifluorescence microscopy. Values obtained by the microscopic method were 10 times higher than plate counts, with a lowest sensitivity limit of ≥6log phage/ml. The interaction of phage ΦAQ113 with its host cell L. helveticus Lh1405 was imaged by AFM after 0, 2 and 5h from phage-host adsorption. The lytic cycle was followed by epifluorescence microscopy counting and the concomitant cell wall changes were visualized by AFM imaging. Our results showed that these two methods can be combined for a reliable phage enumeration and for studying phage and host morphology during infection processes, thus giving a complete overview of phage-host interactions in L. helveticus strains involved in dairy productions. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Effect of streptozotocin-induced diabetes on left ventricular function in adult rats: an in vivo Pinhole Gated SPECT study

    Directory of Open Access Journals (Sweden)

    Weytjens Caroline

    2007-10-01

    Full Text Available Abstract Background Recent studies have suggested that diabetes mellitus (DM may cause left ventricular (LV dysfunction directly resulting in increased susceptibility to heart failure. Using pinhole collimators and advances in data processing, gated SPECT was recently adapted to image the rat heart. The present study was aimed to assess this new imaging technique for quantifying LV function and remodeling from the Streptozotocin (STZ rat model compared to controls. Methods Twenty one rats were randomly assigned to control or diabetic group. Six months after the induction of diabetes by STZ, Pinhole 99 m Tc-sestamibi gated SPECT was performed for determining rat LV volumes and function. Post-mortem histopathologic analysis was performed to evaluate the determinant of LV remodeling in this model. Results After six months, the normalized to body weight LV End-systolic volume was significantly different in diabetic rats compared to controls (0.46 ± 0.02 vs 0.33 ± 0.03 μL/g; p = 0.01. The normalized LV End-diastolic volume was also different in both groups (1.51 ± 0.03 vs 0.88 ± 0.05 μL/g; p = 0.001 and the normalized stroke volume was significantly higher in STZ-rats (1.05 ± 0.02 vs 0.54 ± 0.06 μL/g; p = 0.001. The muscular fibers were thinner at histology in the diabetic rats (0.44 ± 0.07 vs 0.32 ± 0.06 AU; p = 0.01. Conclusion Pinhole 99 m Tc-sestamibi gated SPECT can successfully be applied for the evaluation of cardiac function and remodeling in STZ-induced diabetic rats. In this model, LV volumes were significantly changed compared to a control population, leading to a LV dysfunction. These findings were consistent with the histopathological abnormalities. Finally, these data further suggest the presence of diabetes cardiomyopathy.

  4. Improved image quality in pinhole SPECT by accurate modeling of the point spread function in low magnification systems

    International Nuclear Information System (INIS)

    Pino, Francisco; Roé, Nuria; Aguiar, Pablo; Falcon, Carles; Ros, Domènec; Pavía, Javier

    2015-01-01

    Purpose: Single photon emission computed tomography (SPECT) has become an important noninvasive imaging technique in small-animal research. Due to the high resolution required in small-animal SPECT systems, the spatially variant system response needs to be included in the reconstruction algorithm. Accurate modeling of the system response should result in a major improvement in the quality of reconstructed images. The aim of this study was to quantitatively assess the impact that an accurate modeling of spatially variant collimator/detector response has on image-quality parameters, using a low magnification SPECT system equipped with a pinhole collimator and a small gamma camera. Methods: Three methods were used to model the point spread function (PSF). For the first, only the geometrical pinhole aperture was included in the PSF. For the second, the septal penetration through the pinhole collimator was added. In the third method, the measured intrinsic detector response was incorporated. Tomographic spatial resolution was evaluated and contrast, recovery coefficients, contrast-to-noise ratio, and noise were quantified using a custom-built NEMA NU 4–2008 image-quality phantom. Results: A high correlation was found between the experimental data corresponding to intrinsic detector response and the fitted values obtained by means of an asymmetric Gaussian distribution. For all PSF models, resolution improved as the distance from the point source to the center of the field of view increased and when the acquisition radius diminished. An improvement of resolution was observed after a minimum of five iterations when the PSF modeling included more corrections. Contrast, recovery coefficients, and contrast-to-noise ratio were better for the same level of noise in the image when more accurate models were included. Ring-type artifacts were observed when the number of iterations exceeded 12. Conclusions: Accurate modeling of the PSF improves resolution, contrast, and recovery

  5. Improved image quality in pinhole SPECT by accurate modeling of the point spread function in low magnification systems

    Energy Technology Data Exchange (ETDEWEB)

    Pino, Francisco [Unitat de Biofísica, Facultat de Medicina, Universitat de Barcelona, Barcelona 08036, Spain and Servei de Física Mèdica i Protecció Radiològica, Institut Català d’Oncologia, L’Hospitalet de Llobregat 08907 (Spain); Roé, Nuria [Unitat de Biofísica, Facultat de Medicina, Universitat de Barcelona, Barcelona 08036 (Spain); Aguiar, Pablo, E-mail: pablo.aguiar.fernandez@sergas.es [Fundación Ramón Domínguez, Complexo Hospitalario Universitario de Santiago de Compostela 15706, Spain and Grupo de Imagen Molecular, Instituto de Investigacións Sanitarias de Santiago de Compostela (IDIS), Galicia 15782 (Spain); Falcon, Carles; Ros, Domènec [Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona 08036, Spain and CIBER en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona 08036 (Spain); Pavía, Javier [Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona 080836 (Spain); CIBER en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona 08036 (Spain); and Servei de Medicina Nuclear, Hospital Clínic, Barcelona 08036 (Spain)

    2015-02-15

    Purpose: Single photon emission computed tomography (SPECT) has become an important noninvasive imaging technique in small-animal research. Due to the high resolution required in small-animal SPECT systems, the spatially variant system response needs to be included in the reconstruction algorithm. Accurate modeling of the system response should result in a major improvement in the quality of reconstructed images. The aim of this study was to quantitatively assess the impact that an accurate modeling of spatially variant collimator/detector response has on image-quality parameters, using a low magnification SPECT system equipped with a pinhole collimator and a small gamma camera. Methods: Three methods were used to model the point spread function (PSF). For the first, only the geometrical pinhole aperture was included in the PSF. For the second, the septal penetration through the pinhole collimator was added. In the third method, the measured intrinsic detector response was incorporated. Tomographic spatial resolution was evaluated and contrast, recovery coefficients, contrast-to-noise ratio, and noise were quantified using a custom-built NEMA NU 4–2008 image-quality phantom. Results: A high correlation was found between the experimental data corresponding to intrinsic detector response and the fitted values obtained by means of an asymmetric Gaussian distribution. For all PSF models, resolution improved as the distance from the point source to the center of the field of view increased and when the acquisition radius diminished. An improvement of resolution was observed after a minimum of five iterations when the PSF modeling included more corrections. Contrast, recovery coefficients, and contrast-to-noise ratio were better for the same level of noise in the image when more accurate models were included. Ring-type artifacts were observed when the number of iterations exceeded 12. Conclusions: Accurate modeling of the PSF improves resolution, contrast, and recovery

  6. Computed tomography of lethal medline granuloma

    International Nuclear Information System (INIS)

    Lee, Ho Suk; Kim, Tae Ho; Suh, Kyung Jin; Kim, Tae Hun; Kim, Yong Joo; Kang, Duk Sik

    1991-01-01

    In order to clarify the CT findings of lethal midline granuloma (LMG) diagnosed clinically or histopathologically, the authors retrospectively analyzed 12 patients who were seen at Kyungpook National University Hospital from February 1985 to August 1989. CT showed nasal mucosal thickening and / or soft tissue mass (9 case), spreading of the lesions along the facial subcutaneous fat plane (8 cases), invasion into the paranasal sinuses (5 cases), bone destruction (5 cases), nasopharyngeal mass lesion (2 cases), and extension of the lesion into the infratemporal fossa (1 case). In spite of the fact that CT does not make definitive diagnosis of LMG, it permits evaluation of the extent of the lesion, detection of the combined lesion, differential diagnosis, and close monitoring of its evolution under treatment

  7. Gluconeogenesis in lethally X-irradiated rats

    International Nuclear Information System (INIS)

    Paulikova, E.; Ahlers, I.; Praslicka, M.

    1983-01-01

    The in vivo incorporation of U- 14 C-alanine into blood glucose and liver glycogen was measured in rats irradiated with a single whole body lethal dose of X-rays. Changes in gluconeogenic enzyme activities were studied in the liver. Increased incorporation of 14 C-alanine into blood glucose and liver glycogen were found after irradiation. Liver phosphoenolpyruvate carboxykinase and glycogenic activity underwent almost parallel changes and were significantly elevated from the 6th to the 48th hour, with resultant accumulation of glycogen. Glucose-6-phosphatase activity was depressed and there was a negative correlation between it and liver glycogen concentration. Maximum fructose-1,6-diphosphatase activity was found at 48 hours. The results show that glycogen accumulation in the liver and the raised blood glucose level in X-irradiated rats are based on raised gluconeogenesis. (author)

  8. Gluconeogenesis in lethally X-irradiated rats

    Energy Technology Data Exchange (ETDEWEB)

    Paulikova, E.; Ahlers, I.; Praslicka, M. (Univerzita P.J. Safarika, Kosice (Czechoslovakia). Katedra Vseobecnej Biologie)

    1983-02-01

    The in vivo incorporation of U-/sup 14/C-alanine into blood glucose and liver glycogen was measured in rats irradiated with a single whole body lethal dose of X-rays. Changes in gluconeogenic enzyme activities were studied in the liver. Increased incorporation of /sup 14/C-alanine into blood glucose and liver glycogen were found after irradiation. Liver phosphoenolpyruvate carboxykinase and glycogenic activity underwent almost parallel changes and were significantly elevated from the 6th to the 48th hour, with resultant accumulation of glycogen. Glucose-6-phosphatase activity was depressed and there was a negative correlation between it and liver glycogen concentration. Maximum fructose-1,6-diphosphatase activity was found at 48 hours. The results show that glycogen accumulation in the liver and the raised blood glucose level in X-irradiated rats are based on raised gluconeogenesis.

  9. Ants defend aphids against lethal disease

    Science.gov (United States)

    Nielsen, Charlotte; Agrawal, Anurag A.; Hajek, Ann E.

    2010-01-01

    Social insects defend their own colonies and some species also protect their mutualist partners. In mutualisms with aphids, ants typically feed on honeydew produced by aphids and, in turn guard and shelter aphid colonies from insect natural enemies. Here we report that Formica podzolica ants tending milkweed aphids, Aphis asclepiadis, protect aphid colonies from lethal fungal infections caused by an obligate aphid pathogen, Pandora neoaphidis. In field experiments, bodies of fungal-killed aphids were quickly removed from ant-tended aphid colonies. Ant workers were also able to detect infective conidia on the cuticle of living aphids and responded by either removing or grooming these aphids. Our results extend the long-standing view of ants as mutualists and protectors of aphids by demonstrating focused sanitizing and quarantining behaviour that may lead to reduced disease transmission in aphid colonies. PMID:19923138

  10. Lethal photosensitization of biofilm-grown bacteria

    Science.gov (United States)

    Wilson, Michael

    1997-12-01

    Antibacterial agents are increasingly being used for the prophylaxis and treatment of oral diseases. As these agents can be rendered ineffective by resistance development in the target organisms there is a need to develop alternative antimicrobial approaches. Light-activated antimicrobial agents release singlet oxygen and free radicals which can kill adjacent bacteria and a wide range of cariogenic and periodontopathogenic bacteria has been shown to be susceptible to such agents. In the oral cavity these organisms are present as biofilms (dental plaques) which are less susceptible to traditional antimicrobial agents than bacterial suspensions. The results of these studies have shown that biofilm-grown oral bacteria are also susceptible to lethal photosensitization although the light energy doses required are grater than those needed to kill the organisms when they are grown as aqueous suspensions.

  11. Tityus serrulatus venom--A lethal cocktail.

    Science.gov (United States)

    Pucca, Manuela Berto; Cerni, Felipe Augusto; Pinheiro Junior, Ernesto Lopes; Bordon, Karla de Castro Figueiredo; Amorim, Fernanda Gobbi; Cordeiro, Francielle Almeida; Longhim, Heloisa Tavoni; Cremonez, Caroline Marroni; Oliveira, Guilherme Honda; Arantes, Eliane Candiani

    2015-12-15

    Tityus serrulatus (Ts) is the main scorpion species of medical importance in Brazil. Ts venom is composed of several compounds such as mucus, inorganic salts, lipids, amines, nucleotides, enzymes, kallikrein inhibitor, natriuretic peptide, proteins with high molecular mass, peptides, free amino acids and neurotoxins. Neurotoxins are considered the most responsible for the envenoming syndrome due to their pharmacological action on ion channels such as voltage-gated sodium (Nav) and potassium (Kv) channels. The major goal of this review is to present important advances in Ts envenoming research, correlating both the crude Ts venom and isolated toxins with alterations observed in all human systems. The most remarkable event lies in the Ts induced massive releasing of neurotransmitters influencing, directly or indirectly, the entire body. Ts venom proved to extremely affect nervous and muscular systems, to modulate the immune system, to induce cardiac disorders, to cause pulmonary edema, to decrease urinary flow and to alter endocrine, exocrine, reproductive, integumentary, skeletal and digestive functions. Therefore, Ts venom possesses toxins affecting all anatomic systems, making it a lethal cocktail. However, its low lethality may be due to the low venom mass injected, to the different venom compositions, the body characteristics and health conditions of the victim and the local of Ts sting. Furthermore, we also described the different treatments employed during envenoming cases. In particular, throughout the review, an effort will be made to provide information from an extensive documented studies concerning Ts venom in vitro, in animals and in humans (a total of 151 references). Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. The usefulness of postoperative pinhole bone scintigraphy in the assessment of prognosis after multiple drilling or vascularized bone graft in patients with avascular necrosis of femoral head

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Young An; Kim, Sung Hoon; Cheon, Kyung Ah; Park, Young Ha; Jeong, Soo Kyo [College of Medicine, The Catholic Univ., Seoul (Korea, Republic of); Song Moon Kab [Eulji Medical Center, Taejon (Korea, Republic of)

    1999-08-01

    It is important to evaluate the healing process of avascular necrosis (AVN) involving femoral head after treatment. The purpose of this study was to assess the usefulness of pinhole bone scintigraphy in the AVN of femoral head after surgery. We analyzed the changing pattern of pinhole bone scintigram in 21 femoral heads of 16 patients (14 lesions/11 male, 7 lesions/5 female, mean age : 39.4 yrs) before and after multiple drilling or vascularized bone grafting for AVN of the femoral head. In all patients, pre-operative scintigrams were obtained at 1 to 3 months before treatment and the first post-operative scintigrams were obtained at 1 to 3 months after treatment. All patients were followed for 2 to 4 years after operation. The findings of the pinhole scintigrams were divided into three patterns: 1) curvilinear, 2) scattered spotty and 3) underdetermined. The 10 of 11 lesions with curvilinear pattern had good postoperative clinical and radiological follow-up findings. However, all 6 lesions with scattered spotty pattern showed poor postoperative findings, which necessitated total hip joint replacement. Of the 4 lesions with undetermined pattern, 2 required total hip joint replacement. There was significant difference in postoperative prognosis between the curvilinear and scattered spotty patterns (p<0.05). We conclude that the pattern of pinhole bone scintigram obtained within 1 to 3 months after multiple drilling or vascularized bone graft operation is a useful prognostic indicator in the AVN of femoral head.

  13. The usefulness of postoperative pinhole bone scintigraphy in the assessment of prognosis after multiple drilling or vascularized bone graft in patients with avascular necrosis of femoral head

    International Nuclear Information System (INIS)

    Jeong, Young An; Kim, Sung Hoon; Cheon, Kyung Ah; Park, Young Ha; Jeong, Soo Kyo; Song Moon Kab

    1999-01-01

    It is important to evaluate the healing process of avascular necrosis (AVN) involving femoral head after treatment. The purpose of this study was to assess the usefulness of pinhole bone scintigraphy in the AVN of femoral head after surgery. We analyzed the changing pattern of pinhole bone scintigram in 21 femoral heads of 16 patients (14 lesions/11 male, 7 lesions/5 female, mean age : 39.4 yrs) before and after multiple drilling or vascularized bone grafting for AVN of the femoral head. In all patients, pre-operative scintigrams were obtained at 1 to 3 months before treatment and the first post-operative scintigrams were obtained at 1 to 3 months after treatment. All patients were followed for 2 to 4 years after operation. The findings of the pinhole scintigrams were divided into three patterns: 1) curvilinear, 2) scattered spotty and 3) underdetermined. The 10 of 11 lesions with curvilinear pattern had good postoperative clinical and radiological follow-up findings. However, all 6 lesions with scattered spotty pattern showed poor postoperative findings, which necessitated total hip joint replacement. Of the 4 lesions with undetermined pattern, 2 required total hip joint replacement. There was significant difference in postoperative prognosis between the curvilinear and scattered spotty patterns (p<0.05). We conclude that the pattern of pinhole bone scintigram obtained within 1 to 3 months after multiple drilling or vascularized bone graft operation is a useful prognostic indicator in the AVN of femoral head

  14. A new X-ray pinhole camera for energy dispersive X-ray fluorescence imaging with high-energy and high-spatial resolution

    Energy Technology Data Exchange (ETDEWEB)

    Romano, F.P., E-mail: romanop@lns.infn.it [IBAM, CNR, Via Biblioteca 4, 95124 Catania (Italy); INFN-LNS, Via S. Sofia 62, 95123 Catania (Italy); Altana, C. [INFN-LNS, Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania (Italy); Cosentino, L.; Celona, L.; Gammino, S.; Mascali, D. [INFN-LNS, Via S. Sofia 62, 95123 Catania (Italy); Pappalardo, L. [IBAM, CNR, Via Biblioteca 4, 95124 Catania (Italy); INFN-LNS, Via S. Sofia 62, 95123 Catania (Italy); Rizzo, F. [INFN-LNS, Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania (Italy)

    2013-08-01

    A new X-ray pinhole camera for the Energy Dispersive X-ray Fluorescence (ED-XRF) imaging of materials with high-energy and high-spatial resolution, was designed and developed. It consists of a back-illuminated and deep depleted CCD detector (composed of 1024 × 1024 pixels with a lateral size of 13 μm) coupled to a 70 μm laser-drilled pinhole-collimator, positioned between the sample under analysis and the CCD. The X-ray pinhole camera works in a coaxial geometry allowing a wide range of magnification values. The characteristic X-ray fluorescence is induced on the samples by irradiation with an external X-ray tube working at a maximum power of 100 W (50 kV and 2 mA operating conditions). The spectroscopic capabilities of the X-ray pinhole camera were accurately investigated. Energy response and energy calibration of the CCD detector were determined by irradiating pure target-materials emitting characteristic X-rays in the energy working-domain of the system (between 3 keV and 30 keV). Measurements were performed by using a multi-frame acquisition in single-photon counting. The characteristic X-ray spectra were obtained by an automated processing of the acquired images. The energy resolution measured at the Fe–Kα line is 157 eV. The use of the X-ray pinhole camera for the 2D resolved elemental analysis was investigated by using reference-patterns of different materials and geometries. The possibility of the elemental mapping of samples up to an area of 3 × 3 cm{sup 2} was demonstrated. Finally, the spatial resolution of the pinhole camera was measured by analyzing the profile function of a sharp-edge. The spatial resolution determined at the magnification values of 3.2 × and 0.8 × (used as testing values) is about 90 μm and 190 μm respectively. - Highlights: • We developed an X-ray pinhole camera for the 2D X-ray fluorescence imaging. • X-ray spectra are obtained by a multi-frame acquisition in single photon mode. • The energy resolution in the X

  15. A study of the multiple pinhole coded aperture and the application of the minicomputer in image decoding

    International Nuclear Information System (INIS)

    Hasegawa, Takeo; Hashiba, Hiroshi; Akagi, Kiyoshi; Kobayashi, Akitoshi; Matsuda, Magoichi

    1979-01-01

    Research has been done on optically reconstructed imaging employing the Multiple Pinhole Coded Aperture (hereafter abbreviated as MPCA) in radioisotope tomographic imaging. However, problems remain in the optically reconstructed image method. Therefore, we employed a minicomputer (hereafter abbreviated as CPU) and developed the software for decoding and managing the radioisotope tomographic image. Combining the MPCA and the CPU system, we were able to decode and manage the radioisotope tomographic image. 1) In comparison to the optically decoded MPCA image, various input commands are possibly in the CPU method according to the dialogue between the CPU and the on line typewriter. In addition to this, decoded tomographic images of unrestricted depth are readily attainable. 2) In the CPU method noise elimination and other aspects of image management can be easily performed. (author)

  16. Simultaneous usage of pinhole and penumbral apertures for imaging small scale neutron sources from inertial confinement fusion experiments.

    Science.gov (United States)

    Guler, N; Volegov, P; Danly, C R; Grim, G P; Merrill, F E; Wilde, C H

    2012-10-01

    Inertial confinement fusion experiments at the National Ignition Facility are designed to understand the basic principles of creating self-sustaining fusion reactions by laser driven compression of deuterium-tritium (DT) filled cryogenic plastic capsules. The neutron imaging diagnostic provides information on the distribution of the central fusion reaction region and the surrounding DT fuel by observing neutron images in two different energy bands for primary (13-17 MeV) and down-scattered (6-12 MeV) neutrons. From this, the final shape and size of the compressed capsule can be estimated and the symmetry of the compression can be inferred. These experiments provide small sources with high yield neutron flux. An aperture design that includes an array of pinholes and penumbral apertures has provided the opportunity to image the same source with two different techniques. This allows for an evaluation of these different aperture designs and reconstruction algorithms.

  17. Usefulness of pinhole collimator in differential diagnosis of metastatic disease and degenerative joint disease in the vertebrae

    International Nuclear Information System (INIS)

    Kosuda, Shigeru; Kawahara, Syunji; Ishibashi, Akihiko; Tamura, Kohei; Tsukatani, Yasushi; Fujii, Hiroshi; Kubo, Atsushi; Hashimoto, Shozo.

    1989-01-01

    In order to evaluate the diagnostic efficacy of pinhole collimator (PHC) imaging combined with an X-ray for vertebral metastasis, our prospective study has employed receiver operating characteristics (ROC) analysis in 21 patients, 11 with osseous metastasis and 15 with degenerative joint disease in the lumbar vertebrae. PHC imaging provided better anatomic information on the extent of 99m Tc-MDP accumulation. PHC vertebral scintigraphy had a considerable impact on the decision-making process, although with variations and not very satisfactory results among the physicians with little experience. Our study suggests that PHC imaging and X-ray film are useful in differentiating between osseous metastasis and degenerative joint disease in the vertebra. (author)

  18. EXPERIMENTAL AND MONTE CARLO INVESTIGATIONS OF BCF-12 SMALL‑AREA PLASTIC SCINTILLATION DETECTORS FOR NEUTRON PINHOLE CAMERA.

    Science.gov (United States)

    Bielecki, J; Drozdowicz, K; Dworak, D; Igielski, A; Janik, W; Kulinska, A; Marciniak, L; Scholz, M; Turzanski, M; Wiacek, U; Woznicka, U; Wójcik-Gargula, A

    2017-12-11

    Plastic organic scintillators such as the blue-emitting BCF-12 are versatile and inexpensive tools. Recently, BCF-12 scintillators have been foreseen for investigation of the spatial distribution of neutrons emitted from dense magnetized plasma. For this purpose, small-area (5 mm × 5 mm) detectors based on BCF-12 scintillation rods and Hamamatsu photomultiplier tubes were designed and constructed at the Institute of Nuclear Physics. They will be located inside the neutron pinhole camera of the PF-24 plasma focus device. Two different geometrical layouts and approaches to the construction of the scintillation element were tested. The aim of this work was to determine the efficiency of the detectors. For this purpose, the experimental investigations using a neutron generator and a Pu-Be source were combined with Monte Carlo computations using the Geant4 code. © The Author(s) 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Imaging of striatal dopamine transporters in rat brain with single pinhole SPECT and co-aligned MRI is highly reproducible

    International Nuclear Information System (INIS)

    Booij, Jan; Bruin, Kora de; Win, Maartje M.L. de; Lavini, Cristina Mphil; Heeten, Gerard J. den; Habraken, Jan

    2003-01-01

    A recently developed pinhole high-resolution SPECT system was used to measure striatal to non-specific binding ratios in rats (n = 9), after injection of the dopamine transporter ligand 123 I-FP-CIT, and to assess its test/retest reproducibility. For co-alignment purposes, the rat brain was imaged on a 1.5 Tesla clinical MRI scanner using a specially developed surface coil. The SPECT images showed clear striatal uptake. On the MR images, cerebral and extra-cerebral structures could be easily delineated. The mean striatal to non-specific [ 123 I]FP-CIT binding ratios of the test/retest studies were 1.7 ± 0.2 and 1.6 ± 0.2, respectively. The test/retest variability was approximately 9%. We conclude that the assessment of striatal [ 123 I]FP-CIT binding ratios in rats is highly reproducible

  20. Efficacy and Safety of a Bovine-Associated Staphylococcus aureus Phage Cocktail in a Murine Model of Mastitis

    Directory of Open Access Journals (Sweden)

    Koen Breyne

    2017-11-01

    Full Text Available Overuse of antibiotics is a major problem in the treatment of bovine mastitis, and antibiotic treatment is frequently non-curative, thus alternative treatments are necessary. The primary aim of this study was to evaluate the efficacy of a purified phage cocktail for treatment of bovine Staphylococcus aureus mastitis in a well-defined mouse model. Candidate phages were selected based on their in vitro performance and subsequently processed into an optimally composed phage cocktail. The highest scoring phages were further tested for efficacy and resistance suppression in broth and raw milk, with and without supplemental IgG. As these in vitro results displayed significant decreases in CFU, the cocktail was purified for testing in vivo. Lactating mice were intramammarily inoculated with S. aureus N305 (ATCC 29740, a clinical bovine mastitis isolate commonly used for experimental infection of dairy cows. The phage cocktail was applied via the same route 4 h post-inoculation. Treated mammary glands were graded for gross pathological appearance and excised for bacterial and phage load quantification as well as histopathology. Observation of gross macroscopic and histopathological changes and CFU quantification demonstrated that the phage cocktail treatment significantly improved mastitis pathology and decreased bacterial counts. Phage PFU quantification indicated that the tested phage cocktail treatment was able to maintain high intramammary phage titers without spreading systemically. The in vivo results complement the in vitro data and support our concept of phage therapy as an innovative alternative or supplementation therapy to antibiotics for the treatment of bovine mastitis.

  1. Efficacy and Safety of a Bovine-Associated Staphylococcus aureus Phage Cocktail in a Murine Model of Mastitis.

    Science.gov (United States)

    Breyne, Koen; Honaker, Ryan W; Hobbs, Zachary; Richter, Manuela; Żaczek, Maciej; Spangler, Taylor; Steenbrugge, Jonas; Lu, Rebecca; Kinkhabwala, Anika; Marchon, Bruno; Meyer, Evelyne; Mokres, Lucia

    2017-01-01

    Overuse of antibiotics is a major problem in the treatment of bovine mastitis, and antibiotic treatment is frequently non-curative, thus alternative treatments are necessary. The primary aim of this study was to evaluate the efficacy of a purified phage cocktail for treatment of bovine Staphylococcus aureus mastitis in a well-defined mouse model. Candidate phages were selected based on their in vitro performance and subsequently processed into an optimally composed phage cocktail. The highest scoring phages were further tested for efficacy and resistance suppression in broth and raw milk, with and without supplemental IgG. As these in vitro results displayed significant decreases in CFU, the cocktail was purified for testing in vivo . Lactating mice were intramammarily inoculated with S. aureus N305 (ATCC 29740), a clinical bovine mastitis isolate commonly used for experimental infection of dairy cows. The phage cocktail was applied via the same route 4 h post-inoculation. Treated mammary glands were graded for gross pathological appearance and excised for bacterial and phage load quantification as well as histopathology. Observation of gross macroscopic and histopathological changes and CFU quantification demonstrated that the phage cocktail treatment significantly improved mastitis pathology and decreased bacterial counts. Phage PFU quantification indicated that the tested phage cocktail treatment was able to maintain high intramammary phage titers without spreading systemically. The in vivo results complement the in vitro data and support our concept of phage therapy as an innovative alternative or supplementation therapy to antibiotics for the treatment of bovine mastitis.

  2. Safety analysis of a Russian phage cocktail: From MetaGenomic analysis to oral application in healthy human subjects

    Energy Technology Data Exchange (ETDEWEB)

    McCallin, Shawna, E-mail: semccallin@yahoo.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Alam Sarker, Shafiqul, E-mail: sasarker@icddrb.org [International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212 (Bangladesh); Barretto, Caroline, E-mail: Caroline.Barretto@rdls.nestle.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Sultana, Shamima, E-mail: shamima@icddrb.org [International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212 (Bangladesh); Berger, Bernard, E-mail: bernard.berger@rdls.nestle.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Huq, Sayeda, E-mail: sayeeda@mail.icddrb.org [International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212 (Bangladesh); Krause, Lutz, E-mail: ltz.krause@gmail.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Bibiloni, Rodrigo, E-mail: Rodrigo.Bibiloni@agresearch.co.nz [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Schmitt, Bertrand, E-mail: bertrand.schmitt@rdls.nestle.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Reuteler, Gloria, E-mail: gloria.reuteler@rdls.nestle.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Brüssow, Harald, E-mail: harald.bruessow@rdls.nestle.com [Nestlé Research Centre, Nestec Ltd, Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland)

    2013-09-01

    Phage therapy has a long tradition in Eastern Europe, where preparations are comprised of complex phage cocktails whose compositions have not been described. We investigated the composition of a phage cocktail from the Russian pharmaceutical company Microgen targeting Escherichia coli/Proteus infections. Electron microscopy identified six phage types, with numerically T7-like phages dominating over T4-like phages. A metagenomic approach using taxonomical classification, reference mapping and de novo assembly identified 18 distinct phage types, including 7 genera of Podoviridae, 2 established and 2 proposed genera of Myoviridae, and 2 genera of Siphoviridae. De novo assembly yielded 7 contigs greater than 30 kb, including a 147-kb Myovirus genome and a 42-kb genome of a potentially new phage. Bioinformatic analysis did not reveal undesired genes and a small human volunteer trial did not associate adverse effects with oral phage exposure. - Highlights: • We analyzed the composition of a commercial Russian phage cocktail. • The cocktail consists of at least 10 different phage genera. • No undesired genes were detected. • No adverse effects were seen upon oral application in a small human clinical trial.

  3. Safety analysis of a Russian phage cocktail: From MetaGenomic analysis to oral application in healthy human subjects

    International Nuclear Information System (INIS)

    McCallin, Shawna; Alam Sarker, Shafiqul; Barretto, Caroline; Sultana, Shamima; Berger, Bernard; Huq, Sayeda; Krause, Lutz; Bibiloni, Rodrigo; Schmitt, Bertrand; Reuteler, Gloria; Brüssow, Harald

    2013-01-01

    Phage therapy has a long tradition in Eastern Europe, where preparations are comprised of complex phage cocktails whose compositions have not been described. We investigated the composition of a phage cocktail from the Russian pharmaceutical company Microgen targeting Escherichia coli/Proteus infections. Electron microscopy identified six phage types, with numerically T7-like phages dominating over T4-like phages. A metagenomic approach using taxonomical classification, reference mapping and de novo assembly identified 18 distinct phage types, including 7 genera of Podoviridae, 2 established and 2 proposed genera of Myoviridae, and 2 genera of Siphoviridae. De novo assembly yielded 7 contigs greater than 30 kb, including a 147-kb Myovirus genome and a 42-kb genome of a potentially new phage. Bioinformatic analysis did not reveal undesired genes and a small human volunteer trial did not associate adverse effects with oral phage exposure. - Highlights: • We analyzed the composition of a commercial Russian phage cocktail. • The cocktail consists of at least 10 different phage genera. • No undesired genes were detected. • No adverse effects were seen upon oral application in a small human clinical trial

  4. Adrenal imaging with 131I-adosterol (NCL-6-131I) by diverging and pinhole methods, 1

    International Nuclear Information System (INIS)

    Nakajo, Masayuki

    1981-01-01

    The adrenal diverging and pinhole images with 131 I-Adosterol in 80 subjects with no evidence of adrenal diseases were analyzed to establish the normal adrenal imaging patterns. The results obtained from the analysis of the diverging images were as follows: 1) The right gland was located higher than the left in 69% of the subjects and in 30% both adrenals were located at the same height. In only one subject, the left adrenal was slightly higher than the right. 2) On the posterior view, the right higher asymmetrical uptake was observed in most subjects (62.5%), whereas the symmetrical uptake was most frequently (69%) seen on the anterior view. This discrepancy could be explained by differences in depth, photon attenuation and hepatic overlapping radioactivity between both glands. 3) The adrenal high/low ratio on both views, semiquantitative comparison between both adrenal radioactivities, showed a higher deviation in the right higher group (mean; 1.37, range; 1.01 - 3.15) than in the left higher one, however, its deviation was small (mean; 1.14, range; 1.01 - 1.41). The high deviation values were due to the low uptake of the left glands. The results obtained from the analysis of the pinhole images were as follows: 1) Although the scintigraphic morphology differed essentially between both glands, the left glands were basically divided into oval (64%), triangular (25%), and round (11%) types, whereas the right glands were divided into triangular (64%), oval (25%) and round or sickle (11%) types. 2) The inner radioactive distributions of both glands were characteristic respectively. In 74% of the subjects, the left gland showed higher radioactivity in its upper and/or medial portion, and the radioactivity of the right was higher in its midportion and decreased toward its peripheral region in 76%. According to these results, the important points on interpretation of the adrenal images were discussed. (author)

  5. Resolution improvement and noise reduction in human pinhole SPECT using a multi-ray approach and the SHINE method

    International Nuclear Information System (INIS)

    Seret, A.; Vanhove, C.; Defrise, M.

    2009-01-01

    Purpose: This work aimed at quantifying the gains in spatial resolution and noise that could be achieved when using resolution modelling based on a multi-ray approach and additionally the Statistical and Heuristic Noise Extraction (SHINE) method in human pinhole single photon emission tomography (PH-SPECT). Methods: PH-SPECT of two line phantoms and one homogeneous cylinder were recorded using parameters suited for studies of the human neck area. They were reconstructed using pinhole dedicated ordered subsets expectation maximisation algorithm including a resolution recovery technique based on 7 or 21 rays. Optionally, the SPECT data were SHINE pre-processed. Transverse and axial full widths at half-maximum (FWHM) were obtained from the line phantoms. The noise was quantified using the coefficient of variation (COV) derived from the uniform phantom. Two human PH-SPECT studies of the thyroid (a hot nodule and a very low uptake) were processed with the same algorithms. Results: Depending on the number of iterations, FWHM decreased by 30 to 50% when using the multi-ray approach in the reconstruction process. The SHINE method did not affect the resolution but decreased the COV by at least 20% and by 45% when combined with the multi-ray method. The two human studies illustrated the gain in spatial resolution and the decrease in noise afforded both by the multi-ray reconstruction and the SHINE method. Conclusion: Iterative reconstruction with resolution modelling allows to obtain high resolution human PH-SPECT studies with reduced noise content. The SHINE method affords an additional noise reduction without compromising the resolution. (orig.)

  6. Estimation of the Contribution of Primary and Secondary Radiation to a Pinhole Volume from a Water Phantom

    International Nuclear Information System (INIS)

    Gamage, Kelum-A.-A.; Joyce, Malcolm-J.; Taylor, Graeme-C.

    2013-06-01

    The imaging of mixed radiation fields with organic liquid scintillation detectors became feasible as a result of recent advances in digital pulse-shape discrimination methods. The use of a liquid scintillator has significant benefits over other techniques for imaging radiation environments as the acquired data can be analysed to provide separate information about the gamma and neutron emissions from a source (or sources) in a single scan in near real-time. This method has significant potential for the location of radioactive sources in radiation environments in the nuclear industry, nuclear decommissioning and homeland security applications. A further application of the mixed-field imaging system would be to detect, locate and study the secondary radiation produced during proton therapy. Proton therapy uses a particle accelerator to target a tumour within the body with a beam of protons. The presence of materials in the beam path as well as the patient, leads to the production of secondary particles such as neutrons and gamma rays. In this paper the contribution of scattered and secondary radiation from a water phantom to a pinhole volume, as a result of three neutron sources and two gamma sources, is separately estimated using the PTRAC particle tracking option available in MCNP. A spherical tally volume, 2 cm in diameter, was placed equidistantly from a radioactive source and 30*30*15 cm 3 water phantom. Monte Carlo simulations have been carried out to investigate the level of primary and secondary radiation contributing to the pinhole volume from interactions in the phantom. This can be used as a simple method to visualise the results expected from the mixed-field imaging system. The results have shown that the percentage of neutrons reflected from the phantom with energies above 1 MeV goes up with mean energy of the source. (authors)

  7. Oral T4-like phage cocktail application to healthy adult volunteers from Bangladesh

    International Nuclear Information System (INIS)

    Sarker, Shafiqul Alam; McCallin, Shawna; Barretto, Caroline; Berger, Bernard; Pittet, Anne-Cécile; Sultana, Shamima; Krause, Lutz; Huq, Sayeda; Bibiloni, Rodrigo; Bruttin, Anne; Reuteler, Gloria; Brüssow, Harald

    2012-01-01

    The genomic diversity of 99 T4-like coliphages was investigated by sequencing an equimolar mixture with Illumina technology and screening them against different databases for horizontal gene transfer and undesired genes. A 9-phage cocktail was given to 15 healthy adults from Bangladesh at a dose of 3×10 9 and 3×10 7 plaque-forming units and placebo respectively. Phages were detected in 64% of the stool samples when subjects were treated with higher titer phage, compared to 30% and 28% with lower-titer phage and placebo, respectively. No Escherichia coli was present in initial stool samples, and no amplification of phage was observed. One percent of the administered oral phage was recovered from the feces. No adverse events were observed by self-report, clinical examination, or from laboratory tests for liver, kidney, and hematology function. No impact of oral phage was seen on the fecal microbiota composition with respect to bacterial 16S rRNA from stool.

  8. Restriction of phage T4 internal protein I mutants by a strain of Escherichia coli

    International Nuclear Information System (INIS)

    Black, L.W.; Abremski, K.

    1974-01-01

    Phage T4 internal protein I(IPI), a small (ca, 10,000 MW), basic protein injected into the host with the phage DNA, is not required for infection of most hosts, but mutants defective in IPI are restricted by at least one naturally occurring strain of Escherichia coli, CT 596 (CT). Phages lacking IPI (IPI - ) appear to inject their DNA and bind it to the membrane of CT cells as well as wild-type phage T4 does, but shutoff of host protein synthesis, initiation of T4 protein synthesis, and cell killing are abnormal in the IPI - mutant infected CT host. The injection of IPI appears to be important in allowing T4 DNA to carry out early steps involved in takeover of this host. Restriction of IPI - phage growth by CT cells appears to be due, at least in part, to a defective prophage it harbors which renders the host resistant to successful infection by phage T4 which lack IPI or rII functions. Bacteria cured of this prophage can be infected by mutants defective in these functions. The resistance of CT cells to other coliphages, and the question of T-even phage internal protein diversity are discussed. (U.S.)

  9. Non-targeted mutagenesis of unirradiated lambda phage in Escherichia coli

    International Nuclear Information System (INIS)

    Wood, R.D.; Hutchinson, F.

    1984-01-01

    Non-targeted mutagenesis of lambda phage by ultraviolet light is the increase over background mutagenesis when non-irradiated phage are grown in irradiated Escherichia coli host cells. Such mutagenesis is caused by different processes from targeted mutagenesis, in which mutations in irradiated phage are correlated with photoproducts in the phage DNA. Non-irradiated phage grown in heavily irradiated uvr + host cells showed non-targeted mutations, which were 3/4 frameshifts, whereas targeted mutations were 2/3 transitions. For non-targeted mutagenesis in heavily irradiated host cells, there were one or two mutant phage per mutant burst. From the results of a series of experiments with various mutant host cells, a major pathway of non-targeted mutagenesis by ultraviolet light was proposed which acts in addition to ''SOS induction''. This pathway involves binding of the enzyme DNA polymerase I to damaged genomic DNA, and low polymerase activity leads to frameshift mutations during semiconservative DNA replication. The data suggest that this process will play a much smaller role in ultraviolet mutagenesis of the bacterial genome than it does in the mutagenesis of lambda phage. (author)

  10. Phage Conversion for β-Lactam Antibiotic Resistance of Staphylococcus aureus from Foods.

    Science.gov (United States)

    Lee, Young-Duck; Park, Jong-Hyun

    2016-02-01

    Temperate phages have been suggested to carry virulence factors and other lysogenic conversion genes that play important roles in pathogenicity. In this study, phage TEM123 in wild-type Staphylococcus aureus from food sources was analyzed with respect to its morphology, genome sequence, and antibiotic resistance conversion ability. Phage TEM123 from a mitomycin C-induced lysate of S. aureus was isolated from foods. Morphological analysis under a transmission electron microscope revealed that it belonged to the family Siphoviridae. The genome of phage TEM123 consisted of a double-stranded DNA of 43,786 bp with a G+C content of 34.06%. A bioinformatics analysis of the phage genome identified 43 putative open reading frames (ORFs). ORF1 encoded a protein that was nearly identical to the metallo-β-lactamase enzymes that degrade β-lactam antibiotics. After transduction to S. aureus with phage TEM123, the metallo-β-lactamase gene was confirmed in the transductant by PCR and sequencing analyses. In a β-lactam antibiotic susceptibility test, the transductant was more highly resistant to β-lactam antibiotics than S. aureus S133. Phage TEM123 might play a role in the transfer of β-lactam antibiotic resistance determinants in S. aureus. Therefore, we suggest that the prophage of S. aureus with its exotoxin is a risk factor for food safety in the food chain through lateral gene transfer.

  11. ORIGINAL ARTICLE: Multidrug Resistance and Phage Pattern of Staphylococcus aureus in Pyoderma Cases

    Directory of Open Access Journals (Sweden)

    Sanjay M. Wavare

    2012-01-01

    Full Text Available Background: Pyoderma is common in India and other tropical countries. Staphylococcus aureus is the commonest causative agent ofpyoderma. Aims and Objectives: To know the antibiotic susceptibility and bacteriophage pattern of Staphylococcus aureus isolated from pyoderma infection. Materials and Methods: One hundred clinically diagnosed pyoderma cases were investigated bacteriologically. A total of 59 isolates of S. aureus were subjected to antibioticsusceptibility testing by Kirby Bauer’s disk diffusion method and phage typing by routine test dilution X 100 bacteriophages. Results: Most of the strains were resistant to penicillin, ampicillin and were susceptible to gentamicin, streptomycin and erythromycin. Multidrug resistance was also high among these strains. Regarding the phage types, Phage type 52 (15 strains, 96 (8 strains and 71(16strains were predominant among the typed strains (55.95% of S. aureus. The most common group was mixed phage group (17% followed by phage group I (13.55%. Conclusion: Knowledge of antibioticsusceptibility pattern is essential to give proper antibiotic therapy and avoid unnecessary medication with non-effective drugs, which may increase resistance. Gentamicin, streptomycin and erythromycin are the drugs of choice in that order. Association of phage typing and antibiotic sensitivity of S. aureus showed the predominance of phage group III with greater frequency of penicillin resistance.

  12. Selection of phage-displayed peptides for the detection of imidacloprid in water and soil.

    Science.gov (United States)

    Liu, Zhiping; Liu, Jianfeng; Wang, Kai; Li, Wenhui; Shelver, Weilin L; Li, Qing X; Li, Ji; Xu, Ting

    2015-09-15

    Imidacloprid is the most widely used neonicotinoid insecticide in the world and shows widespread environment and human exposures. A phage clone designated L7-1 that selectively binds to imidacloprid was selected from a commercial phage display library containing linear 7-mer randomized amino acid residues. Using the clone L7-1, a competitive enzyme-linked immunosorbent assay (ELISA) for imidacloprid was developed. The half-maximum signal inhibition concentration (IC50) and the limit of detection (LOD) of the phage ELISA for imidacloprid were 96 and 2.3 ng ml(-1), respectively. This phage ELISA showed relatively low cross-reactivity with all of the tested compounds structurally similar to imidacloprid, less than 2% with the exception of 6-chloronicotinic acid, a metabolite of imidacloprid that showed 11.5%. The average recoveries of the phage ELISA for imidacloprid in water and soil samples were in the ranges of 74.6 to 86.3% and 72.5 to 93.6%, respectively. The results of the competitive phage ELISA for imidacloprid in the fortified samples agreed well with those of a high-performance liquid chromatography (HPLC) method. The simple phage-displayed peptide technology has been proven to be a convenient and efficient method for the development of an alternative format of ELISA for small molecules. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Phage typing or CRISPR typing for epidemiological surveillance of Salmonella Typhimurium?

    Science.gov (United States)

    Mohammed, Manal

    2017-11-07

    Salmonella Typhimurium is the most dominant Salmonella serovar around the world. It is associated with foodborne gastroenteritis outbreaks but has recently been associated with invasive illness and deaths. Characterization of S. Typhimurium is therefore very crucial for epidemiological surveillance. Phage typing has been used for decades for subtyping of S. Typhimurium to determine the epidemiological relation among isolates. Recent studies however have suggested that high throughput clustered regular interspaced short palindromic repeats (CRISPR) typing has the potential to replace phage typing. This study aimed to determine the efficacy of high-throughput CRISPR typing over conventional phage typing in epidemiological surveillance and outbreak investigation of S. Typhimurium. In silico analysis of whole genome sequences (WGS) of well-documented phage types of S. Typhimurium reveals the presence of different CRISPR type among strains belong to the same phage type. Furthermore, different phage types of S. Typhimurium share identical CRISPR type. Interestingly, identical spacers were detected among outbreak and non-outbreak associated DT8 strains of S. Typhimurium. Therefore, CRISPR typing is not useful for the epidemiological surveillance and outbreak investigation of S. Typhimurium and phage typing, until it is replaced by WGS, is still the gold standard method for epidemiological surveillance of S. Typhimurium.

  14. Non-targeted mutagenesis of unirradiated lambda phage in Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Wood, R.D.; Hutchinson, F. (Yale Univ., New Haven, CT (USA). Dept. of Molecular Biophysics and Biochemistry)

    1984-03-05

    Non-targeted mutagenesis of lambda phage by ultraviolet light is the increase over background mutagenesis when non-irradiated phage are grown in irradiated Escherichia coli host cells. Such mutagenesis is caused by different processes from targeted mutagenesis, in which mutations in irradiated phage are correlated with photoproducts in the phage DNA. Non-irradiated phage grown in heavily irradiated uvr/sup +/ host cells showed non-targeted mutations, which were 3/4 frameshifts, whereas targeted mutations were 2/3 transitions. For non-targeted mutagenesis in heavily irradiated host cells, there were one or two mutant phage per mutant burst. From the results of a series of experiments with various mutant host cells, a major pathway of non-targeted mutagenesis by ultraviolet light was proposed which acts in addition to ''SOS induction''. This pathway involves binding of the enzyme DNA polymerase I to damaged genomic DNA, and low polymerase activity leads to frameshift mutations during semiconservative DNA replication. The data suggest that this process will play a much smaller role in ultraviolet mutagenesis of the bacterial genome than it does in the mutagenesis of lambda phage.

  15. Oral T4-like phage cocktail application to healthy adult volunteers from Bangladesh

    Energy Technology Data Exchange (ETDEWEB)

    Sarker, Shafiqul Alam, E-mail: sasarker@icddrb.org [International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212 (Bangladesh); McCallin, Shawna; Barretto, Caroline [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Berger, Bernard, E-mail: bernard.berger@rdls.nestle.com [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Pittet, Anne-Cecile [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Sultana, Shamima, E-mail: shamima@icddrb.org [International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212 (Bangladesh); Krause, Lutz, E-mail: ltz.krause@gmail.com [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Huq, Sayeda, E-mail: sayeeda@mail.icddrb.org [International Centre for Diarrhoeal Diseases Research, Bangladesh (icddr,b), 68 Shaheed Tajuddin Ahmed Sharani, Mohakhali, Dhaka 1212 (Bangladesh); Bibiloni, Rodrigo, E-mail: Rodrigo.Bibiloni@agresearch.co.nz [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Bruttin, Anne, E-mail: anne.bruttin@rdls.nestle.com [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Reuteler, Gloria, E-mail: gloria.reuteler@rdls.nestle.com [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland); Bruessow, Harald, E-mail: harald.bruessow@rdls.nestle.com [Nestle Research Centre, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne 26 (Switzerland)

    2012-12-20

    The genomic diversity of 99 T4-like coliphages was investigated by sequencing an equimolar mixture with Illumina technology and screening them against different databases for horizontal gene transfer and undesired genes. A 9-phage cocktail was given to 15 healthy adults from Bangladesh at a dose of 3 Multiplication-Sign 10{sup 9} and 3 Multiplication-Sign 10{sup 7} plaque-forming units and placebo respectively. Phages were detected in 64% of the stool samples when subjects were treated with higher titer phage, compared to 30% and 28% with lower-titer phage and placebo, respectively. No Escherichia coli was present in initial stool samples, and no amplification of phage was observed. One percent of the administered oral phage was recovered from the feces. No adverse events were observed by self-report, clinical examination, or from laboratory tests for liver, kidney, and hematology function. No impact of oral phage was seen on the fecal microbiota composition with respect to bacterial 16S rRNA from stool.

  16. Development of a Phage Cocktail to Control Proteus mirabilis Catheter-associated Urinary Tract Infections

    Science.gov (United States)

    Melo, Luís D. R.; Veiga, Patrícia; Cerca, Nuno; Kropinski, Andrew M.; Almeida, Carina; Azeredo, Joana; Sillankorva, Sanna

    2016-01-01

    Proteus mirabilis is an enterobacterium that causes catheter-associated urinary tract infections (CAUTIs) due to its ability to colonize and form crystalline biofilms on the catheters surface. CAUTIs are very difficult to treat, since biofilm structures are highly tolerant to antibiotics. Phages have been used widely to control a diversity of bacterial species, however, a limited number of phages for P. mirabilis have been isolated and studied. Here we report the isolation of two novel virulent phages, the podovirus vB_PmiP_5460 and the myovirus vB_PmiM_5461, which are able to target, respectively, 16 of the 26 and all the Proteus strains tested in this study. Both phages have been characterized thoroughly and sequencing data revealed no traces of genes associated with lysogeny. To further evaluate the phages’ ability to prevent catheter’s colonization by Proteus, the phages adherence to silicone surfaces was assessed. Further tests in phage-coated catheters using a dynamic biofilm model simulating CAUTIs, have shown a significant reduction of P. mirabilis biofilm formation up to 168 h of catheterization. These results highlight the potential usefulness of the two isolated phages for the prevention of surface colonization by this bacterium. PMID:27446059

  17. Novel use of gamma correction for precise {sup 99m}Tc-HDP pinhole bone scan diagnosis and classification of knee occult fractures

    Energy Technology Data Exchange (ETDEWEB)

    Bahk, Yong-Whee [Sung Ae General Hospital, Department of Nuclear Medicine, Seoul (Korea); Jeon, Ho-Seung [Sung Ae General Hospital, Department of Orthopedic Surgery, Seoul (Korea); Kim, Jang Min [Sung Ae General Hospital, Department of Radiology, Seoul (Korea); Park, Jung Mee; Kim, Sung-Hoon; Chung, Soo-Kyo [The Catholic University of Korea, Department of Radiology, College of Medicine, Seoul (Korea); Chung, Yong-An [The Catholic University of Korea, Department of Radiology, College of Medicine, Seoul (Korea); Incheon St. Mary' s Hospital, Institute of Catholic Integrative Medicine (ICIM), Incheon (Korea); Incheon St. Mary' s Hospital, The Catholic University of Korea, Department of Radiology, Incheon (Korea); Kim, E.E. [University of Texas MD Anderson Cancer Center, Department of Radiology and Nuclear Medicine, Houston, TX (United States)

    2010-08-15

    The aim of this study was to introduce gamma correction pinhole bone scan (GCPBS) to depict specific signs of knee occult fractures (OF) on {sup 99m}Tc-hydroxydiphosphonate (HDP) scan. Thirty-six cases of six different types of knee OF in 27 consecutive patients (male = 20, female = 7, and age = 18-86 years) were enrolled. The diagnosis was made on the basis of a history of acute or subacute knee trauma, local pain, tenderness, cutaneous injury, negative conventional radiography, and positive magnetic resonance imaging (MRI). Because of the impracticability of histological verification of individual OF, MRI was utilized as a gold standard of diagnosis and classification. All patients had {sup 99m}Tc-HDP bone scanning and supplementary GCPBS. GCPBS signs were correlated and compared with those of MRI. The efficacy of gamma correction of ordinary parallel collimator and pinhole collimator scans were collated. Gamma correction pinhole bone scan depicted the signs characteristic of six different types of OF. They were well defined stuffed globular tracer uptake in geographic I fractures (n = 9), block-like uptake in geographic II fractures (n = 7), simple or branching linear uptake in linear cancellous fractures (n = 4), compression in impacted fractures (n = 2), stippled-serpentine uptake in reticular fractures (n = 11), and irregular subcortical uptake in osteochondral fractures (n = 3). All fractures were equally well or more distinctly depicted on GCPBS than on MRI except geographic II fracture, the details of which were not appreciated on GCPBS. Parallel collimator scan also yielded to gamma correction, but the results were inferior to those of the pinhole scan. Gamma correction pinhole bone scan can depict the specific diagnostic signs in six different types of knee occult fractures. The specific diagnostic capability along with the lower cost and wider global availability of bone scanning would make GCPBS an effective alternative. (orig.)

  18. Novel use of gamma correction for precise 99mTc-HDP pinhole bone scan diagnosis and classification of knee occult fractures

    International Nuclear Information System (INIS)

    Bahk, Yong-Whee; Jeon, Ho-Seung; Kim, Jang Min; Park, Jung Mee; Kim, Sung-Hoon; Chung, Soo-Kyo; Chung, Yong-An; Kim, E.E.

    2010-01-01

    The aim of this study was to introduce gamma correction pinhole bone scan (GCPBS) to depict specific signs of knee occult fractures (OF) on 99m Tc-hydroxydiphosphonate (HDP) scan. Thirty-six cases of six different types of knee OF in 27 consecutive patients (male = 20, female = 7, and age = 18-86 years) were enrolled. The diagnosis was made on the basis of a history of acute or subacute knee trauma, local pain, tenderness, cutaneous injury, negative conventional radiography, and positive magnetic resonance imaging (MRI). Because of the impracticability of histological verification of individual OF, MRI was utilized as a gold standard of diagnosis and classification. All patients had 99m Tc-HDP bone scanning and supplementary GCPBS. GCPBS signs were correlated and compared with those of MRI. The efficacy of gamma correction of ordinary parallel collimator and pinhole collimator scans were collated. Gamma correction pinhole bone scan depicted the signs characteristic of six different types of OF. They were well defined stuffed globular tracer uptake in geographic I fractures (n = 9), block-like uptake in geographic II fractures (n = 7), simple or branching linear uptake in linear cancellous fractures (n = 4), compression in impacted fractures (n = 2), stippled-serpentine uptake in reticular fractures (n = 11), and irregular subcortical uptake in osteochondral fractures (n = 3). All fractures were equally well or more distinctly depicted on GCPBS than on MRI except geographic II fracture, the details of which were not appreciated on GCPBS. Parallel collimator scan also yielded to gamma correction, but the results were inferior to those of the pinhole scan. Gamma correction pinhole bone scan can depict the specific diagnostic signs in six different types of knee occult fractures. The specific diagnostic capability along with the lower cost and wider global availability of bone scanning would make GCPBS an effective alternative. (orig.)

  19. Lethal and Mutagenic Effects of Tritium Decay Produced by Tritiated Compounds Incorporated into Bacteria and Bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Person, S. [Pennsylvania State University, University Park, PA (United States)

    1968-06-15

    The work discussed below is predominantly from the author's laboratory. Some effects of tritium decay on bacteria and bacteriophages, using labelled compounds that are incorporated preferentially into DNA, RNA or protein, have been studied. A relatively high killing efficiency, the probability that a single decay produces loss of colony-forming ability in bacteria or loss of plaque-forming ability in bacteriophages, is observed for thymidine- methyl-{sup 3}H decay, but this is thought to be due to S-particle ionization damage. The most definitive experiments involved a comparison of killing efficiencies for decays originating as thymidine-methyl-{sup 3}H in phage DNA and as amino acid-{sup 3}H in phage protein with the calculated {beta}-particle path length through, the DNA in the two cases. Experimental and calculated values are essentially the same. Radiation-dose calculations to many different bacterial sub-volumes were determined for several different distributions of radioactivity. The high killing efficiency for thymidine-methyl- {sup 3}H decay can be explained by {beta}-particle ionizations, providing DNA is the sensitive target molecule and it is organized in a central volume of the cell (see also Ref.[24]). Although both the lethal and mutagenic effect of thymidine-methyl-{sup 3}H and amino acid-{sup 3}H decays can readily be explained on the basis of {beta}-particle ionizations, the observed large mutation frequency produced by uracil-5{sup 3}H decay cannot. The majority of mutations produced by uracil-5{sup 3}H decays are due to a specific chemical rearrangement of the parent molecule, since decays from uracil-6{sup 3}H are 6 to 7-fold less mutagenic. It is clear that the decays leading to mutations for cells labelled with uracil-5{sup 3}H originate as cytosine-5{sup 3}H in bacterial DNA. Recent work shows that the specific chemical rearrangement causes a C --> T(u) genetic coding change. (author)

  20. Chronic exposure of corals to fine sediments: lethal and sub-lethal impacts.

    Directory of Open Access Journals (Sweden)

    Florita Flores

    Full Text Available Understanding the sedimentation and turbidity thresholds for corals is critical in assessing the potential impacts of dredging projects in tropical marine systems. In this study, we exposed two species of coral sampled from offshore locations to six levels of total suspended solids (TSS for 16 weeks in the laboratory, including a 4 week recovery period. Dose-response relationships were developed to quantify the lethal and sub-lethal thresholds of sedimentation and turbidity for the corals. The sediment treatments affected the horizontal foliaceous species (Montipora aequituberculata more than the upright branching species (Acropora millepora. The lowest sediment treatments that caused full colony mortality were 30 mg l(-1 TSS (25 mg cm(-2 day(-1 for M. aequituberculata and 100 mg l(-1 TSS (83 mg cm(-2 day(-1 for A. millepora after 12 weeks. Coral mortality generally took longer than 4 weeks and was closely related to sediment accumulation on the surface of the corals. While measurements of damage to photosystem II in the symbionts and reductions in lipid content and growth indicated sub-lethal responses in surviving corals, the most reliable predictor of coral mortality in this experiment was long-term sediment accumulation on coral tissue.

  1. Chronic Exposure of Corals to Fine Sediments: Lethal and Sub-Lethal Impacts

    Science.gov (United States)

    Flores, Florita; Hoogenboom, Mia O.; Smith, Luke D.; Cooper, Timothy F.; Abrego, David; Negri, Andrew P.

    2012-01-01

    Understanding the sedimentation and turbidity thresholds for corals is critical in assessing the potential impacts of dredging projects in tropical marine systems. In this study, we exposed two species of coral sampled from offshore locations to six levels of total suspended solids (TSS) for 16 weeks in the laboratory, including a 4 week recovery period. Dose-response relationships were developed to quantify the lethal and sub-lethal thresholds of sedimentation and turbidity for the corals. The sediment treatments affected the horizontal foliaceous species (Montipora aequituberculata) more than the upright branching species (Acropora millepora). The lowest sediment treatments that caused full colony mortality were 30 mg l−1 TSS (25 mg cm−2 day−1) for M. aequituberculata and 100 mg l−1 TSS (83 mg cm−2 day−1) for A. millepora after 12 weeks. Coral mortality generally took longer than 4 weeks and was closely related to sediment accumulation on the surface of the corals. While measurements of damage to photosystem II in the symbionts and reductions in lipid content and growth indicated sub-lethal responses in surviving corals, the most reliable predictor of coral mortality in this experiment was long-term sediment accumulation on coral tissue. PMID:22662225

  2. Prevalence, Host Range, and Comparative Genomic Analysis of Temperate Ochrobactrum Phages

    Directory of Open Access Journals (Sweden)

    Claudia Jäckel

    2017-06-01

    Full Text Available Ochrobactrum and Brucella are closely related bacteria that populate different habitats and differ in their pathogenic properties. Only little is known about mobile genetic elements in these genera which might be important for survival and virulence. Previous studies on Brucella lysogeny indicated that active phages are rare in this genus. To gain insight into the presence and nature of prophages in Ochrobactrum, temperate phages were isolated from various species and characterized in detail. In silico analyses disclosed numerous prophages in published Ochrobactrum genomes. Induction experiments showed that Ochrobactrum prophages can be induced by various stress factors and that some strains released phage particles even under non-induced conditions. Sixty percent of lysates prepared from 125 strains revealed lytic activity. The host range and DNA similarities of 19 phages belonging to the families Myoviridae, Siphoviridae, or Podoviridae were determined suggesting that they are highly diverse. Some phages showed relationship to the temperate Brucella inopinata phage BiPB01. The genomic sequences of the myovirus POA1180 (41,655 bp and podovirus POI1126 (60,065 bp were analyzed. Phage POA1180 is very similar to a prophage recently identified in a Brucella strain isolated from an exotic frog. The POA1180 genome contains genes which may confer resistance to chromate and the ability to take up sulfate. Phage POI1126 is related to podoviruses of Sinorhizobium meliloti (PCB5, Erwinia pyrifoliae (Pep14, and Burkholderia cenocepacia (BcepIL02 and almost identical to an unnamed plasmid of the Ochrobactrum intermedium strain LMG 3301. Further experiments revealed that the POI1126 prophage indeed replicates as an extrachromosomal element. The data demonstrate for the first time that active prophages are common in Ochrobactrum and suggest that atypical brucellae also may be a reservoir for temperate phages.

  3. Characterization of a ViI-like Phage Specific to Escherichia coli O157:H7

    Directory of Open Access Journals (Sweden)

    Kropinski Andrew M

    2011-09-01

    Full Text Available Abstract Phage vB_EcoM_CBA120 (CBA120, isolated against Escherichia coli O157:H7 from a cattle feedlot, is morphologically very similar to the classic phage ViI of Salmonella enterica serovar Typhi. Until recently, little was known genetically or physiologically about the ViI-like phages, and none targeting E. coli have been described in the literature. The genome of CBA120 has been fully sequenced and is highly similar to those of both ViI and the Shigella phage AG3. The core set of structural and replication-related proteins of CBA120 are homologous to those from T-even phages, but generally are more closely related to those from T4-like phages of Vibrio, Aeromonas and cyanobacteria than those of the Enterobacteriaceae. The baseplate and method of adhesion to the host are, however, very different from those of either T4 or the cyanophages. None of the outer baseplate proteins are conserved. Instead of T4's long and short tail fibers, CBA120, like ViI, encodes tail spikes related to those normally seen on podoviruses. The 158 kb genome, like that of T4, is circularly permuted and terminally redundant, but unlike T4 CBA120 does not substitute hmdCyt for cytosine in its DNA. However, in contrast to other coliphages, CBA120 and related coliphages we have isolated cannot incorporate 3H-thymidine (3H-dThd into their DNA. Protein sequence comparisons cluster the putative "thymidylate synthase" of CBA120, ViI and AG3 much more closely with those of Delftia phage φW-14, Bacillus subtilis phage SPO1, and Pseudomonas phage YuA, all known to produce and incorporate hydroxymethyluracil (hmdUra.

  4. Selection of gonadotrophin surge attenuating factor phage antibodies by bioassay.

    Science.gov (United States)

    Sorsa-Leslie, Tarja; Mason, Helen D; Harris, William J; Fowler, Paul A

    2005-09-26

    We aimed to combine the generation of "artificial" antibodies with a rat pituitary bioassay as a new strategy to overcome 20 years of difficulties in the purification of gonadotrophin surge-attenuating factor (GnSAF). A synthetic single-chain antibody (Tomlinson J) phage display library was bio-panned with partially purified GnSAF produced by cultured human granulosa/luteal cells. The initial screening with a simple binding immunoassay resulted in 8 clones that were further screened using our in-vitro rat monolayer bioassay for GnSAF. Initially the antibodies were screened as pooled phage forms and subsequently as individual, soluble, single-chain antibody (scAbs) forms. Then, in order to improve the stability of the scAbs for immunopurification purposes, and to widen the range of labelled secondary antibodies available, these were engineered into full-length human immunoglobulins. The immunoglobulin with the highest affinity for GnSAF and a previously described rat anti-GnSAF polyclonal antiserum was then used to immunopurify bioactive GnSAF protein. The two purified preparations were electrophoresed on 1-D gels and on 7 cm 2-D gels (pH 4-7). The candidate GnSAF protein bands and spots were then excised for peptide mass mapping. Three of the scAbs recognised GnSAF bioactivity and subsequently one clone of the purified scAb-derived immunoglobulin demonstrated high affinity for GnSAF bioactivity, also binding the molecule in such as way as to block its bioactivity. When used for repeated immunopurification cycles and then Western blot, this antibody enabled the isolation of a GnSAF-bioactive protein band at around 66 kDa. Similar results were achieved using the rat anti-GnSAF polyclonal antiserum. The main candidate molecules identified from the immunopurified material by excision of 2-D gel protein spots was human serum albumin precursor and variants. This study demonstrates that the combination of bioassay and phage display technologies is a powerful tool in the

  5. Development of phage/antibody immobilized magnetostrictive biosensors

    Science.gov (United States)

    Fu, Liling

    There is an urgent need for biosensors that are able to detect and quantify the presence of a small amount of pathogens in a real-time manner accurately and quickly to guide prevention efforts and assay food and water quality. Acoustic wave (AW) devices, whose performance is defined by mass sensitivity (Sm) and quality factor (Q value), have been extensively studied as high performance biosensor platforms. However, current AW devices still face some challenges such as the difficulty to be employed in liquid and low Q value in practical applications. The objective of this research is to develop magnetostrictive sensors which include milli/microcantilever type (MSMC) and particle type (MSP). Compared to other AW devices, MSMC exhibits the following advantages: (1) wireless/remote driving and sensing; (2) easy to fabricate; (3) works well in liquid; (4) exhibits a high Q value (> 500 in air). The fundamental study of the damping effect on MSMCs from the surrounding media including air and liquids were conducted to improve the Q value of MSMCs. The experiment results show that the Q value is dependent on the properties of surrounding media (e.g. viscosity, density), the geometry of the MSMCs, and the harmonic mode on the resonance behavior of MSMCs, etc. The phage-coated MSMC has high specificity and sensitivity even while used in water with a low concentration of targeted bacteria. Two currently developed phages, JRB7 and E2, respectively respond to Bacillus anthracis spores and Salmonella typhimurium, were employed as bio-recognition elements in this research. The phage-immobilized MSMC biosensors exhibited high performance and detection of limit was 5 x 104 cfu/ml for the MSMC in size of 1.4 x 0.8 x 0.035 mm. The MSMC-based biosensors were indicated as a very potential method for in-situ monitoring of the biological quality in water. The MSP combine antibody was used to detect Staphylococcus aureus in this experiment. The interface between MSPs and antibody was

  6. Radiosensitivity of the induction of early enzymes by. gamma. -irradiated T7-phages

    Energy Technology Data Exchange (ETDEWEB)

    Bopp, E

    1975-01-01

    The radiosensitivity of the ability of the bacteriophage T7 to produce polymerase and lysozyme during its reproduction cycle is investigated. B-cells of Escherichia coli were infected with /sup 60/Co-..gamma..-irradiated T7 phages. From the extracts of the cells opened by ultrasonic waves, the amount of enzymes produced is determined with the aid of special enzyme tests. The fraction of inactivated phages able to produce RNA polymerase is higher than the fraction with intact DNA double strands and higher than the fraction able to inject DNA. The lowest fraction is that of inactivated phages producing lysozyme.

  7. Photoreactivation of cells and phages inactivated by UV of ecological wave-lengths

    International Nuclear Information System (INIS)

    Samojlova, K.A.; Yanovska, Eh.; Vizdalova, M.; Ceskoslovenska Akademie Ved, Brno. Biofysikalni Ustav)

    1979-01-01

    It has been found that the photoreactivity of infusoria Paramecium caudatum and bacteria Escherichia coli is high and practically similar if they are irradiated with short-wave (254 nm) and mean-wave (300-315 nm) UV radiation. The cells damaged with long-wave (315-400 nm) UV rays are not photoactivated. The latter is caused by the appearance of nonphotoreactivated damages since the phages jrradiated with the same UV rays are reactivated extremely weakly in the intact cells of bacteria (phage T7) or are not reactivated at all (phage lambdasub(c1 857))

  8. Phenotypic resistance and the dynamics of bacterial escape from phage control

    DEFF Research Database (Denmark)

    Bull, James J.; Vegge, Christina Skovgaard; Schmerer, Matthew

    2014-01-01

    The canonical view of phage - bacterial interactions in dense, liquid cultures is that the phage will eliminate most of the sensitive cells; genetic resistance will then ascend to restore high bacterial densities. Yet there are various mechanisms by which bacteria may remain sensitive to phages...... mathematical models of these processes and suggest how different types of this 'phenotypic' resistance may be elucidated. We offer preliminary in vitro studies of a previously characterized E. coli model system and Campylobacter jejuni illustrating apparent phenotypic resistance. As phenotypic resistance may...

  9. Bacteriophage T4 Infection of Stationary Phase E. coli: Life after Log from a Phage Perspective

    Directory of Open Access Journals (Sweden)

    Elizabeth Martin Kutter

    2016-09-01

    Full Text Available Virtually all studies of phage infections investigate bacteria growing exponentially in rich media. In nature, however, phages largely encounter non-growing cells. Bacteria entering stationary phase often activate well-studied stress defense mechanisms that drastically alter the cell, facilitating its long-term survival. An understanding of phage-host interactions in such conditions is of major importance from both an ecological and therapeutic standpoint. Here, we show that bacteriophage T4 can efficiently bind to, infect and kill E. coli in stationary phase, both in the presence and absence of a functional stationary-phase sigma factor, and explore the response of T4-infected stationary phase cells to the addition of fresh nutrients 5 or 24 hours after that infection. An unexpected new mode of response has been identified. Hibernation mode is a persistent but reversible dormant state in which the infected cells make at least some phage enzymes, but halt phage development until appropriate nutrients become available before producing phage particles. Our evidence indicates that the block in hibernation mode occurs after the middle-mode stage of phage development; host DNA breakdown and the incorporation of the released nucleotides into phage DNA indicate that the enzymes of the nucleotide synthesizing complex, under middle-mode control, have been made and assembled into a functional state. Once fresh glucose and amino acids become available, the standard lytic infection process rapidly resumes and concentrations of up to 1011 progeny phage (an average of about 40 phage per initially-present cell are produced. All evidence is consistent with the hibernation-mode control point lying between middle mode and late mode T4 gene expression. We have also observed a scavenger response, where the infecting phage takes advantage of whatever few nutrients are available to produce small quantities of progeny within 2 to 5 hours after infection. The scavenger

  10. Directed synthesis of bio-inorganic vanadium oxide composites using genetically modified filamentous phage

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Michael; Baik, Seungyun [Environmental Safety Group, Korea Institute of Science and Technology Europe (KIST-Europe) Forschungsgesellschaft mbH, Campus E 7 1, Saarbruecken (Germany); Jeon, Hojeong; Kim, Yuchan [Center for Biomaterials, Biomedical Research Institute Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Kim, Jungtae [Environmental Safety Group, Korea Institute of Science and Technology Europe (KIST-Europe) Forschungsgesellschaft mbH, Campus E 7 1, Saarbruecken (Germany); Kim, Young Jun, E-mail: youngjunkim@kist-europe.de [Environmental Safety Group, Korea Institute of Science and Technology Europe (KIST-Europe) Forschungsgesellschaft mbH, Campus E 7 1, Saarbruecken (Germany)

    2015-05-15

    Highlights: • Phage is an excellent seeding for bio-templates for environmentally benign vanadium oxide nanocomposite synthesis. • The synthesized bio-inorganic vanadium oxide showed photodegradation activities. • The fabricated wt phage/vanadium oxide composite exhibited bundle-like structure. • The fabricated RSTB-phage/vanadium oxide composite exhibited a ball with a fiber-like nanostructure. • The virus/vanadium oxide composite could be applied in photocatalysts, sensors and nanoelectronic applications. - Abstract: The growth of crystalline vanadium oxide using a filamentous bacteriophage template was investigated using sequential incubation in a V{sub 2}O{sub 5} precursor. Using the genetic modification of the bacteriophage, we displayed two cysteines that constrained the RSTB-1 peptide on the major coat protein P8, resulting in vanadium oxide crystallization. The phage-driven vanadium oxide crystals with different topologies, microstructures, photodegradation and vanadium oxide composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), quartz microbalance and dissipation (QCM-D) and X-ray photoelectron spectroscopy (XPS). Non-specific electrostatic attraction between a wild-type phage (wt-phage) and vanadium cations in the V{sub 2}O{sub 5} precursor caused phage agglomeration and fiber formation along the length of the viral scaffold. As a result, the addition of recombinant phage (re-phage) in V{sub 2}O{sub 5} precursors formed heterogeneous structures, which led to efficient condensation of vanadium oxide crystal formation in lines, shown by QCM-D analysis. Furthermore, re-phage/V{sub x}O{sub x} composites showed significantly enhanced photodegradation activities compared with the synthesized wt-phage-V{sub 2}O{sub 5} composite under illumination. This study demonstrates that peptide-mediated vanadium oxide mineralization is governed by a complicated interplay of peptide sequence, local structure

  11. Use of phages to control Vibrio splendidus infection in the juvenile sea cucumber Apostichopus japonicus.

    Science.gov (United States)

    Li, Zhen; Li, Xiaoyu; Zhang, Jiancheng; Wang, Xitao; Wang, Lili; Cao, Zhenhui; Xu, Yongping

    2016-07-01

    In the present study, we isolated 3 bacteriophages with the ability to control Vibrio splendidus, a bacterium known to cause disease in the juvenile sea cucumber. These bacteriophages were designated as vB_VspS_VS-ABTNL-1 (PVS-1), vB_VspS_VS-ABTNL-2 (PVS-2) and vB_VspS_VS-ABTNL-3 (PVS-3). The ability of the 3 phages to inhibit the growth of V. splendidus VS-ABTNL was tested in vitro using each of the 3 phages individually or in the form of a cocktail of all 3 phages in the proportion of 1:1:1. All treated cultures produced a significant (P sea cucumbers (23 ± 2 g) were randomly assigned to 1 of 6 treatments. Each treatment was housed in 3 PVC tanks (38 cm × 54 cm × 80 cm) with 20 sea cucumbers per tank. Six diets were prepared including an unsupplemented control diet, antibiotic treatment diet, 3 diets containing 1 of the 3 phages individually and a diet containing a cocktail of all 3 phages. After 60 days of feeding, all sea cucumber were challenged with V. splendidus VS-ABTNL by immersion in sea water containing a bacterial concentration of 6 × 10(6) CFU/mL for 2 days. The survival rate of sea cucumbers during the next 10 days was 18% for the unsupplemented diet, 82% for the antibiotic treatment, 82% for the phage cocktail, 65% for phage PVS-1, 58% for phage PVS-2 and 50% for phage PVS-3. There were no significant differences in weight gain, ingestion rate or feed conversion among sea cucumber fed the 4 phage treatments compared with those fed the unsupplemented diet (P > 0.05). The levels of nitric oxide synthase and acid phosphatase of sea cucumbers fed phage-containing diets were significantly (P  0.05) were detected among the 4 phage-fed treatments. An additional study was conducted in which 60 healthy sea cucumbers (23 ± 2 g) were randomly assigned to a control, an untreated group and a test group to investigate the effects of injecting phages by coelomic injection on the survival rate and enzyme activities in the coelomic fluid

  12. Functional alignment of regulatory networks: a study of temperate phages.

    Directory of Open Access Journals (Sweden)

    Ala Trusina

    2005-12-01

    Full Text Available The relationship between the design and functionality of molecular networks is now a key issue in biology. Comparison of regulatory networks performing similar tasks can provide insights into how network architecture is constrained by the functions it directs. Here, we discuss methods of network comparison based on network architecture and signaling logic. Introducing local and global signaling scores for the difference between two networks, we quantify similarities between evolutionarily closely and distantly related bacteriophages. Despite the large evolutionary separation between phage lambda and 186, their networks are found to be similar when difference is measured in terms of global signaling. We finally discuss how network alignment can be used to pinpoint protein similarities viewed from the network perspective.

  13. Lethal and sub-lethal effects of five pesticides used in rice farming on the earthworm Eisenia fetida

    NARCIS (Netherlands)

    Rico, Andreu; Sabater, Consuelo; Castillo, María Ángeles

    2016-01-01

    The toxicity of five pesticides typically used in rice farming (trichlorfon, dimethoate, carbendazim, tebuconazole and prochloraz) was evaluated on different lethal and sub-lethal endpoints of the earthworm Eisenia fetida. The evaluated endpoints included: avoidance behaviour after an exposure

  14. The genome of the Erwinia amylovora phage PhiEaH1 reveals greater diversity and broadens the applicability of phages for the treatment of fire blight.

    Science.gov (United States)

    Meczker, Katalin; Dömötör, Dóra; Vass, János; Rákhely, Gábor; Schneider, György; Kovács, Tamás

    2014-01-01

    The enterobacterium Erwinia amylovora is the causal agent of fire blight. This study presents the analysis of the complete genome of phage PhiEaH1, isolated from the soil surrounding an E. amylovora-infected apple tree in Hungary. Its genome is 218 kb in size, containing 244 ORFs. PhiEaH1 is the second E. amylovora infecting phage from the Siphoviridae family whose complete genome sequence was determined. Beside PhiEaH2, PhiEaH1 is the other active component of Erwiphage, the first bacteriophage-based pesticide on the market against E. amylovora. Comparative genome analysis in this study has revealed that PhiEaH1 not only differs from the 10 formerly sequenced E. amylovora bacteriophages belonging to other phage families, but also from PhiEaH2. Sequencing of more Siphoviridae phage genomes might reveal further diversity, providing opportunities for the development of even more effective biological control agents, phage cocktails against Erwinia fire blight disease of commercial fruit crops.

  15. Antigen-antibody reactions of UV-irradiated phage DNA

    International Nuclear Information System (INIS)

    Fink, A.

    1976-01-01

    The observation of others could be confirmed that UV-irradiated DNA is a better immunogen than unirradiated DNA. The author's immune sera contained a high amount of antibodies with a specific action against photoproducts in the DNA. The thymine dimer was identified as relevant photoproduct and thus as antigenic determinant. In comparison, the amount of unspecific antibodies reacting with denaturated DNA was low and varied between sera. Thymin-dimer antibodies showed a high specificity without cross-reaction with other pyrimidine dimers such as anti CC and anti CT; they belong to the class of IgG molecules. UV-irradiated dinucleotide dTpT is sufficient to induce the formation of antibodies reacting with the cis-syn thymine dimers in UV-irradiated DNA. Antibody binding is proportional to the UV doses applied to the DNA. When using completely denaturated DNA, there is a linear increase changing into a plateau at higher doses. The extent of antigen-antibody binding is strongly dependent on the degree of denaturation of the DNA. With increasing denaturation, the antibody binding of the DNA increases. The antigen-antibody reaction can thus be used to estimate the degree of denaturation of the DNA. There were no signs of an influence of the degree of denaturation of the DNA on the quantum yield of thymine dimers. The different amounts of antibodies is therefore due to the masking of thymine dimers in native DNA. When irradiating intact phage particles, there was no sign of an influence of the phages' protein covers on the antibody binding capacity of DNA compared with DNA irradiated in vitro. (orig.) [de

  16. Lethal endomyocarditis caused by chronic "Krokodil" intoxication.

    Science.gov (United States)

    Sorrentino, Antonella; Trotta, Silvia; Colucci, Anna Pia; Aventaggiato, Lucia; Marzullo, Andrea; Solarino, Biagio

    2018-03-19

    "Krokodil" is a home-made opioid drug obtained by synthesizing desomorphine from codeine and combining it with other low-cost additives. Initially introduced in the former Soviet countries, it was then imported to Western Europe as a heroin substitute. To our knowledge, this is the first report of an Italian case of lethal krokodil abuse, that occurred in a 39-year-old man, who died suddenly after transportation to the Emergency Department (ED) for hyperthermia associated with sweating, dyspnoea and tachycardia. Post-mortem examination revealed extensive necrotic ulcerative lesions on the forearms, and autopsy showed a hypertrophic heart with ample endocardial vegetation on the aortic valve and patency of the foramen ovale. Histopathological examination of the heart showed ulcero-vegetative lesions of the aortic valve with an abscess on the annulus and extension to the periaortic adipose tissue, as well as diffuse myocardial interstitial inflammatory neutrophilic infiltrates. Toxicological analysis demonstrated a desomorphine metabolite in urine. On the basis of all these findings the cause of death was ruled to be congestive heart failure caused by endocarditis and myocarditis, correlated with chronic abuse of krokodil.

  17. Tumor clone dynamics in lethal prostate cancer.

    Science.gov (United States)

    Carreira, Suzanne; Romanel, Alessandro; Goodall, Jane; Grist, Emily; Ferraldeschi, Roberta; Miranda, Susana; Prandi, Davide; Lorente, David; Frenel, Jean-Sebastien; Pezaro, Carmel; Omlin, Aurelius; Rodrigues, Daniel Nava; Flohr, Penelope; Tunariu, Nina; S de Bono, Johann; Demichelis, Francesca; Attard, Gerhardt

    2014-09-17

    It is unclear whether a single clone metastasizes and remains dominant over the course of lethal prostate cancer. We describe the clonal architectural heterogeneity at different stages of disease progression by sequencing serial plasma and tumor samples from 16 ERG-positive patients. By characterizing the clonality of commonly occurring deletions at 21q22, 8p21, and 10q23, we identified multiple independent clones in metastatic disease that are differentially represented in tissue and circulation. To exemplify the clinical utility of our studies, we then showed a temporal association between clinical progression and emergence of androgen receptor (AR) mutations activated by glucocorticoids in about 20% of patients progressing on abiraterone and prednisolone or dexamethasone. Resistant clones showed a complex dynamic with temporal and spatial heterogeneity, suggesting distinct mechanisms of resistance at different sites that emerged and regressed depending on treatment selection pressure. This introduces a management paradigm requiring sequential monitoring of advanced prostate cancer patients with plasma and tumor biopsies to ensure early discontinuation of agents when they become potential disease drivers. Copyright © 2014, American Association for the Advancement of Science.

  18. Human cooperation by lethal group competition.

    Science.gov (United States)

    Egas, Martijn; Kats, Ralph; van der Sar, Xander; Reuben, Ernesto; Sabelis, Maurice W

    2013-01-01

    Why humans are prone to cooperate puzzles biologists, psychologists and economists alike. Between-group conflict has been hypothesized to drive within-group cooperation. However, such conflicts did not have lasting effects in laboratory experiments, because they were about luxury goods, not needed for survival ("looting"). Here, we find within-group cooperation to last when between-group conflict is implemented as "all-out war" (eliminating the weakest groups). Human subjects invested in helping group members to avoid having the lowest collective pay-off, whereas they failed to cooperate in control treatments with random group elimination or with no subdivision in groups. When the game was repeated, experience was found to promote helping. Thus, not within-group interactions alone, not random group elimination, but pay-off-dependent group elimination was found to drive within-group cooperation in our experiment. We suggest that some forms of human cooperation are maintained by multi-level selection: reciprocity within groups and lethal competition among groups acting together.

  19. Genome Sequences of Ilzat and Eleri, Two Phages Isolated Using Microbacterium foliorum NRRL B-24224

    Science.gov (United States)

    Ali, Ilzat; Jones, Acacia Eleri; Mohamed, Aleem

    2018-01-01

    ABSTRACT Bacteriophages Ilzat and Eleri are newly isolated Siphoviridae infecting Microbacterium foliorum NRRL B-24224. The phage genomes are similar in length, G+C content, and architecture and share 62.9% nucleotide sequence identity. PMID:29650566

  20. Phage and bacteria support mutual diversity in a narrowing staircase of coexistence

    DEFF Research Database (Denmark)

    Härter, Jan Olaf Mirko; Mitarai, Namiko; Sneppen, Kim

    2014-01-01

    arms race will typically favor high growth rate, but a phage that infects two bacterial strains differently can occasionally eliminate the fastest growing bacteria. This context-dependent fitness allows abrupt resetting of the 'Red-Queen's race' and constrains the local diversity.......The competitive exclusion principle states that phage diversity M should not exceed bacterial diversity N. By analyzing the steady-state solutions of multistrain equations, we find a new constraint: the diversity N of bacteria living on the same resources is constrained to be M or M+1 in terms...... of the diversity of their phage predators. We quantify how the parameter space of coexistence exponentially decreases with diversity. For diversity to grow, an open or evolving ecosystem needs to climb a narrowing 'diversity staircase' by alternatingly adding new bacteria and phages. The unfolding coevolutionary...

  1. Chloroform-Treated Filamentous Phage as a Bioreceptor for Piezoelectric Sensors

    National Research Council Canada - National Science Library

    Olsen, Eric V; Sykora, Jennifer C; Sorokulova, Iryna B; Petrenko, Valery A; Chen, I-Hsuan; Barbaree, James M; Vodyanoy, Vitaly J

    2005-01-01

    ... and S. typhimurium. ELISA confirmed affinity-selected phage specificity for streptavidin. Spheroid induction was optimized to achieve greatest conversion yields as a function of solvent exposure time and concentration...

  2. Phage-inducible chromosomal islands are ubiquitous within the bacterial universe.

    Science.gov (United States)

    Fillol-Salom, Alfred; Martínez-Rubio, Roser; Abdulrahman, Rezheen F; Chen, John; Davies, Robert; Penadés, José R

    2018-06-06

    Phage-inducible chromosomal islands (PICIs) are a recently discovered family of pathogenicity islands that contribute substantively to horizontal gene transfer, host adaptation and virulence in Gram-positive cocci. Here we report that similar elements also occur widely in Gram-negative bacteria. As with the PICIs from Gram-positive cocci, their uniqueness is defined by a constellation of features: unique and specific attachment sites, exclusive PICI genes, a phage-dependent mechanism of induction, conserved replication origin organization, convergent mechanisms of phage interference, and specific packaging of PICI DNA into phage-like infectious particles, resulting in very high transfer frequencies. We suggest that the PICIs represent two or more distinct lineages, have spread widely throughout the bacterial world, and have diverged much more slowly than their host organisms or their prophage cousins. Overall, these findings represent the discovery of a universal class of mobile genetic elements.

  3. Semi-Solid and Solid Dosage Forms for the Delivery of Phage Therapy to Epithelia

    Science.gov (United States)

    Petrovski, Steve; Chan, Hiu Tat; Angove, Michael J.; Tucci, Joseph

    2018-01-01

    The delivery of phages to epithelial surfaces for therapeutic outcomes is a realistic proposal, and indeed one which is being currently tested in clinical trials. This paper reviews some of the known research on formulation of phages into semi-solid dosage forms such as creams, ointments and pastes, as well as solid dosage forms such as troches (or lozenges and pastilles) and suppositories/pessaries, for delivery to the epithelia. The efficacy and stability of these phage formulations is discussed, with a focus on selection of optimal semi-solid bases for phage delivery. Issues such as the need for standardisation of techniques for formulation as well as for assessment of efficacy are highlighted. These are important when trying to compare results from a range of experiments and across different delivery bases. PMID:29495355

  4. Membrane insertion and assembly of epitope-tagged gp9 at the tip of the M13 phage

    Directory of Open Access Journals (Sweden)

    Kuhn Andreas

    2011-09-01

    Full Text Available Abstract Background Filamentous M13 phage extrude from infected Escherichia coli with a tip structure composed of gp7 and gp9. This tip structure is extended by the assembly of the filament composed of the major coat protein gp8. Finally, gp3 and gp6 terminate the phage structure at the proximal end. Up to now, gp3 has been the primary tool for phage display technology. However, gp7, gp8 and gp9 could also be used for phage display and these phage particles should bind to two different or more surfaces when the modified coat proteins are combined. Therefore, we tested here if the amino-terminal end of gp9 can be modified and whether the modified portion is exposed and detectable on the M13 phage particles. Results The amino-terminal region of gp9 was modified by inserting short sequences that encode antigenic epitopes. We show here that the modified gp9 proteins correctly integrate into the membrane using the membrane insertase YidC exposing the modified epitope into the periplasm. The proteins are then efficiently assembled onto the phage particles. Also extensions up to 36 amino acid residues at the amino-terminal end of gp9 did not interfere with membrane integration and phage assembly. The exposure of the antigenic tags on the phage was visualised with immunogold labelling by electron microscopy and verified by dot blotting with antibodies to the tags. Conclusions Our results suggest that gp9 at the phage tip is suitable for the phage display technology. The modified gp9 can be supplied in trans from a plasmid and fully complements M13 phage with an amber mutation in gene 9. The modified phage tip is very well accessible to antibodies.

  5. Using Rose’s metal alloy as a pinhole collimator material in preclinical small-animal imaging: A Monte Carlo evaluation

    International Nuclear Information System (INIS)

    Peterson, Mikael; Strand, Sven-Erik; Ljungberg, Michael

    2015-01-01

    Purpose: Pinhole collimation is the most common method of high-resolution preclinical single photon emission computed tomography imaging. The collimators are usually constructed from dense materials with high atomic numbers, such as gold and platinum, which are expensive and not always flexible in the fabrication step. In this work, the authors have investigated the properties of a fusible alloy called Rose’s metal and its potential in pinhole preclinical imaging. When compared to current standard pinhole materials such as gold and platinum, Rose’s metal has a lower density and a relatively low effective atomic number. However, it is inexpensive, has a low melting point, and does not contract when solidifying. Once cast, the piece can be machined with high precision. The aim of this study was to evaluate the imaging properties for Rose’s metal and compare them with those of standard materials. Methods: After validating their Monte Carlo code by comparing its results with published data and the results from analytical calculations, they investigated different pinhole geometries by varying the collimator material, acceptance angle, aperture diameter, and photon incident angle. The penetration-to-scatter and penetration-to-total component ratios, sensitivity, and the spatial resolution were determined for gold, tungsten, and Rose’s metal for two radionuclides, 99 Tc m and 125 I. Results: The Rose’s metal pinhole-imaging simulations show higher penetration/total and scatter/total ratios. For example, the penetration/total is 50% for gold and 75% for Rose’s metal when simulating 99 Tc m with a 0.3 mm aperture diameter and a 60° acceptance angle. However, the degradation in spatial resolution remained below 10% relative to the spatial resolution for gold for acceptance angles below 40° and aperture diameters larger than 0.5 mm. Conclusions: Extra penetration and scatter associated with Rose’s metal contribute to degradation in the spatial resolution, but

  6. Complete Genome Sequence of EtG, the First Phage Sequenced from Erwinia tracheiphila.

    Science.gov (United States)

    Andrade-Domínguez, Andrés; Kolter, Roberto; Shapiro, Lori R

    2018-02-22

    Erwinia tracheiphila is the causal agent of bacterial wilt of cucurbits. Here, we report the genome sequence of the temperate phage EtG, which was isolated from an E. tracheiphila -infected cucumber plant. Phage EtG has a linear 30,413-bp double-stranded DNA genome with cohesive ends and 45 predicted open reading frames. Copyright © 2018 Andrade-Domínguez et al.

  7. A human gut phage catalog correlates the gut phageome with type 2 diabetes.

    Science.gov (United States)

    Ma, Yingfei; You, Xiaoyan; Mai, Guoqin; Tokuyasu, Taku; Liu, Chenli

    2018-02-01

    Substantial efforts have been made to link the gut bacterial community to many complex human diseases. Nevertheless, the gut phages are often neglected. In this study, we used multiple bioinformatic methods to catalog gut phages from whole-community metagenomic sequencing data of fecal samples collected from both type II diabetes (T2D) patients (n = 71) and normal Chinese adults (n = 74). The definition of phage operational taxonomic units (pOTUs) and identification of large phage scaffolds (n = 2567, ≥ 10 k) revealed a comprehensive human gut phageome with a substantial number of novel sequences encoding genes that were unrelated to those in known phages. Interestingly, we observed a significant increase in the number of gut phages in the T2D group and, in particular, identified 7 pOTUs specific to T2D. This finding was further validated in an independent dataset of 116 T2D and 109 control samples. Co-occurrence/exclusion analysis of the bacterial genera and pOTUs identified a complex core interaction between bacteria and phages in the human gut ecosystem, suggesting that the significant alterations of the gut phageome cannot be explained simply by co-variation with the altered bacterial hosts. Alterations in the gut bacterial community have been linked to the chronic disease T2D, but the role of gut phages therein is not well understood. This is the first study to identify a T2D-specific gut phageome, indicating the existence of other mechanisms that might govern the gut phageome in T2D patients. These findings suggest the importance of the phageome in T2D risk, which warrants further investigation.

  8. Recombinant lambda-phage nanobioparticles for tumor therapy in mice models.

    Science.gov (United States)

    Ghaemi, Amir; Soleimanjahi, Hoorieh; Gill, Pooria; Hassan, Zuhair; Jahromi, Soodeh Razeghi M; Roohvand, Farzin

    2010-05-12

    Lambda phages have considerable potential as gene delivery vehicles due to their genetic tractability, low cost, safety and physical characteristics in comparison to other nanocarriers and gene porters. Little is known concerning lambda phage-mediated gene transfer and expression in mammalian hosts. We therefore performed experiments to evaluate lambda-ZAP bacteriophage-mediated gene transfer and expression in vitro. For this purpose, we constructed recombinant lambda-phage nanobioparticles containing a mammalian expression cassette encoding enhanced green fluorescent protein (EGFP) and E7 gene of human papillomavirus type 16 (lambda-HPV-16 E7) using Lambda ZAP- CMV XR vector. Four cell lines (COS-7, CHO, TC-1 and HEK-239) were transduced with the nanobioparticles. We also characterized the therapeutic anti-tumor effects of the recombinant lambda-HPV-16 E7 phage in C57BL/6 tumor mice model as a cancer vaccine. Obtained results showed that delivery and expression of these genes in fibroblastic cells (COS-7 and CHO) are more efficient than epithelial cells (TC-1 and HEK-239) using these nanobioparticles. Despite the same phage M.O.I entry, the internalizing titers of COS-7 and CHO cells were more than TC-1 and HEK-293 cells, respectively. Mice vaccinated with lambda-HPV-16 E7 are able to generate potent therapeutic antitumor effects against challenge with E7- expressing tumor cell line, TC-1 compared to group treated with the wild phage. The results demonstrated that the recombinant lambda-phages, due to their capabilities in transducing mammalian cells, can also be considered in design and construction of novel and safe phage-based nanomedicines.

  9. Phage nanofibers induce vascularized osteogenesis in 3D printed bone scaffolds.

    Science.gov (United States)

    Wang, Jianglin; Yang, Mingying; Zhu, Ye; Wang, Lin; Tomsia, Antoni P; Mao, Chuanbin

    2014-08-06

    A virus-activated matrix is developed to overcome the challenge of forming vascularized bone tissue. It is generated by filling a 3D printed bioceramic scaffold with phage nanofibers displaying high-density RGD peptide. After it is seeded with mesenchymal stem cells (MSCs) and implanted into a bone defect, the phage nanofibers induce osteogenesis and angiogenesis by activating endothelialization and osteogenic differentiation of MSCs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Exploring the Effect of Phage Therapy in Preventing Vibrio anguillarum Infections in Cod and Turbot Larvae

    DEFF Research Database (Denmark)

    Rørbo, Nanna; Rønneseth, Anita; Kalatzis, Panos G.

    2018-01-01

    The aquaculture industry is suffering from losses associated with bacterial infections by opportunistic pathogens. Vibrio anguillarum is one of the most important pathogens, causing vibriosis in fish and shellfish cultures leading to high mortalities and economic losses. Bacterial resistance to a...... KVP40, demonstrating that the phage could also reduce mortality imposed by the background population of pathogens. Overall, phage-mediated reduction in mortality of cod and turbot larvae in experimental challenge assays with V. anguillarum pathogens suggested that application of broad...

  11. Phage adsorption and lytic propagation in Lactobacillus plantarum: Could host cell starvation affect them?

    OpenAIRE

    Briggiler Marc?, Mari?ngeles; Reinheimer, Jorge; Quiberoni, Andrea

    2015-01-01

    Background Bacteriophages constitute a great threat to the activity of lactic acid bacteria used in industrial processes. Several factors can influence the infection cycle of bacteriophages. That is the case of the physiological state of host cells, which could produce inhibition or delay of the phage infection process. In the present work, the influence of Lactobacillus plantarum host cell starvation on phage B1 adsorption and propagation was investigated. Result First, cell growth kinetics ...

  12. Transport of Escherichia coli phage through saturated porous media considering managed aquifer recharge.

    Science.gov (United States)

    Zhang, Wenjing; Li, Shuo; Wang, Shuang; Lei, Liancheng; Yu, Xipeng; Ma, Tianyi

    2018-03-01

    Virus is one of the most potentially harmful microorganisms in groundwater. In this paper, the effects of hydrodynamic and hydrogeochemical conditions on the transportation of the colloidal virus considering managed aquifer recharge were systematically investigated. Escherichia coli phage, vB_EcoM-ep3, has a broad host range and was able to lyse pathogenic Escherichia coli. Bacteriophage with low risk to infect human has been found extensively in the groundwater environment, so it is considered as a representative model of groundwater viruses. Laboratory studies were carried out to analyze the transport of the Escherichia coli phage under varying conditions of pH, ionic strength, cation valence, flow rate, porous media, and phosphate buffer concentration. The results indicated that decreasing the pH will increase the adsorption of Escherichia coli phage. Increasing the ionic strength, either Na + or Ca 2+ , will form negative condition for the migration of Escherichia coli phage. A comparison of different cation valence tests indicated that changes in transport and deposition were more pronounced with divalent Ca 2+ than monovalent Na + . As the flow rate increases, the release of Escherichia coli phage increases and the retention of Escherichia coli phage in the aquifer medium reduces. Changes in porous media had a significant effect on Escherichia coli phage migration. With increase of phosphate buffer concentration, the suspension stability and migration ability of Escherichia coli phage are both increased. Based on laboratory-scale column experiments, a one-dimensional transport model was established to quantitatively describe the virus transport in saturated porous medium.

  13. Interaction between the genomes of Lactococcus lactis and phages of the P335 species

    Science.gov (United States)

    Kelly, William J.; Altermann, Eric; Lambie, Suzanne C.; Leahy, Sinead C.

    2013-01-01

    Phages of the P335 species infect Lactococcus lactis and have been particularly studied because of their association with strains of L. lactis subsp. cremoris used as dairy starter cultures. Unlike other lactococcal phages, those of the P335 species may have a temperate or lytic lifestyle, and are believed to originate from the starter cultures themselves. We have sequenced the genome of L. lactis subsp. cremoris KW2 isolated from fermented corn and found that it contains an integrated P335 species prophage. This 41 kb prophage (Φ KW2) has a mosaic structure with functional modules that are highly similar to several other phages of the P335 species associated with dairy starter cultures. Comparison of the genomes of 26 phages of the P335 species, with either a lytic or temperate lifestyle, shows that they can be divided into three groups and that the morphogenesis gene region is the most conserved. Analysis of these phage genomes in conjunction with the genomes of several L. lactis strains shows that prophage insertion is site specific and occurs at seven different chromosomal locations. Exactly how induced or lytic phages of the P335 species interact with carbohydrate cell surface receptors in the host cell envelope remains to be determined. Genes for the biosynthesis of a variable cell surface polysaccharide and for lipoteichoic acids (LTAs) are found in L. lactis and are the main candidates for phage receptors, as the genes for other cell surface carbohydrates have been lost from dairy starter strains. Overall, phages of the P335 species appear to have had only a minor role in the adaptation of L. lactis subsp. cremoris strains to the dairy environment, and instead they appear to be an integral part of the L. lactis chromosome. There remains a great deal to be discovered about their role, and their contribution to the evolution of the bacterial genome. PMID:24009606

  14. Damages induced in lambda phage DNA by enzyme-generated triplet acetone

    International Nuclear Information System (INIS)

    Menck, C.F.; Cabral Neto, J.B.; Gomes, R.A.; Faljoni-Alario, A.

    1985-01-01

    Exposure of lambda phage to triplet acetone, generated during the aerobic oxidation of isobutanal by peroxidase, leads to genome lesions. The majority of these lesions are detected as DNA single-strand breaks only in alkaline conditions, so true breaks were not observed. Also, no sites sensitive to UV-endonuclease from Micrococcus luteus were found in DNA from treated phage. The participation of triplet acetone in the generation of such DNA damage is discussed. (Author) [pt

  15. Novel type of specialized transduction for CTX phi or its satellite phage RS1 mediated by filamentous phage VGJ phi in Vibrio cholerae.

    Science.gov (United States)

    Campos, Javier; Martínez, Eriel; Marrero, Karen; Silva, Yussuan; Rodríguez, Boris L; Suzarte, Edith; Ledón, Talena; Fando, Rafael

    2003-12-01

    The main virulence factor of Vibrio cholerae, the cholera toxin, is encoded by the ctxAB operon, which is contained in the genome of the lysogenic filamentous phage CTX phi. This phage transmits ctxAB genes between V. cholerae bacterial populations that express toxin-coregulated pilus (TCP), the CTX phi receptor. In investigating new forms of ctxAB transmission, we found that V. cholerae filamentous phage VGJ phi, which uses the mannose-sensitive hemagglutinin (MSHA) pilus as a receptor, transmits CTX phi or its satellite phage RS1 by an efficient and highly specific TCP-independent mechanism. This is a novel type of specialized transduction consisting in the site-specific cointegration of VGJ phi and CTX phi (or RS1) replicative forms to produce a single hybrid molecule, which generates a single-stranded DNA hybrid genome that is packaged into hybrid viral particles designated HybP phi (for the VGJ phi/CTX phi hybrid) and HybRS phi (for the VGJ phi/RS1 hybrid). The hybrid phages replicate by using the VGJ phi replicating functions and use the VGJ phi capsid, retaining the ability to infect via MSHA. The hybrid phages infect most tested strains more efficiently than CTX phi, even under in vitro optimal conditions for TCP expression. Infection and lysogenization with HybP phi revert the V. cholerae live attenuated vaccine strain 1333 to virulence. Our results reinforce that TCP is not indispensable for the acquisition of CTX phi. Thus, we discuss an alternative to the current accepted evolutionary model for the emergence of new toxigenic strains of V. cholerae and the importance of our findings for the development of an environmentally safer live attenuated cholera vaccine.

  16. Emergence of new Salmonella Enteritidis phage types in Europe? Surveillance of infections in returning travellers

    Directory of Open Access Journals (Sweden)

    Andersson Yvonne

    2004-09-01

    Full Text Available Abstract Background Among human Salmonella Enteritidis infections, phage type 4 has been the dominant phage type in most countries in Western Europe during the last years. This is reflected in Salmonella infections among Swedish travellers returning from abroad. However, there are differences in phage type distribution between the countries, and this has also changed over time. Methods We used data from the Swedish infectious disease register and the national reference laboratory to describe phage type distribution of Salmonella Enteritidis infections in Swedish travellers from 1997 to 2002, and have compared this with national studies conducted in the countries visited. Results Infections among Swedish travellers correlate well with national studies conducted in the countries visited. In 2001 a change in phage type distribution in S. Enteritidis infections among Swedish travellers returning from some countries in southern Europe was observed, and a previously rare phage type (PT 14b became one of the most commonly diagnosed that year, continuing into 2002 and 2003. Conclusions Surveillance of infections among returning travellers can be helpful in detecting emerging infections and outbreaks in tourist destinations. The information needs to be communicated rapidly to all affected countries in order to expedite the implementation of appropriate investigations and preventive measures.

  17. Differential screening of phage-ab libraries by oligonucleotide microarray technology.

    Directory of Open Access Journals (Sweden)

    Paolo Monaci

    Full Text Available A novel and efficient tagArray technology was developed that allows rapid identification of antibodies which bind to receptors with a specific expression profile, in the absence of biological information. This method is based on the cloning of a specific, short nucleotide sequence (tag in the phagemid coding for each phage-displayed antibody fragment (phage-Ab present in a library. In order to set up and validate the method we identified about 10,000 different phage-Abs binding to receptors expressed in their native form on the cell surface (10 k Membranome collection and tagged each individual phage-Ab. The frequency of each phage-Ab in a given population can at this point be inferred by measuring the frequency of its associated tag sequence through standard DNA hybridization methods. Using tiny amounts of biological samples we identified phage-Abs binding to receptors preferentially expressed on primary tumor cells rather than on cells obtained from matched normal tissues. These antibodies inhibited cell proliferation in vitro and tumor development in vivo, thus representing therapeutic lead candidates.

  18. The True Story and Advantages of RNA Phage Capsids as Nanotools.

    Science.gov (United States)

    Pumpens, Paul; Renhofa, Regina; Dishlers, Andris; Kozlovska, Tatjana; Ose, Velta; Pushko, Peter; Tars, Kaspars; Grens, Elmars; Bachmann, Martin F

    2016-01-01

    RNA phages are often used as prototypes for modern recombinant virus-like particle (VLP) technologies. Icosahedral RNA phage VLPs can be formed from coat proteins (CPs) and are efficiently produced in bacteria and yeast. Both genetic fusion and chemical coupling have been successfully used for the production of numerous chimeras based on RNA phage VLPs. In this review, we describe advances in RNA phage VLP technology along with the history of the Leviviridae family, including its taxonomical organization, genomic structure, and important role in the development of molecular biology. Comparative 3D structures of different RNA phage VLPs are used to explain the level of VLP tolerance to foreign elements displayed on VLP surfaces. We also summarize data that demonstrate the ability of CPs to tolerate different organic (peptides, oligonucleotides, and carbohydrates) and inorganic (metal ions) compounds either chemically coupled or noncovalently added to the outer and/or inner surfaces of VLPs. Finally, we present lists of nanotechnological RNA phage VLP applications, such as experimental vaccines constructed by genetic fusion and chemical coupling methodologies, nanocontainers for targeted drug delivery, and bioimaging tools. © 2016 S. Karger AG, Basel.

  19. [Construction of human phage antibody library and screening for human monoclonal antibodies of amylin].

    Science.gov (United States)

    Gong, Qian; Li, Chang-ying; Chang, Ji-wu; Zhu, Tie-hong

    2012-06-01

    To screen monoclonal antibodies to amylin from a constructed human phage antibody library and identify their antigenic specificity and combining activities. The heavy chain Fd fragment and light chain of human immunoglobulin genes were amplified from peripheral blood lymphocytes of healthy donors using RT-PCR, and then inserted into phagemid pComb3XSS to generate a human phage antibody library. The insertion of light chain or heavy chain Fd genes were identified by PCR after the digestion of Sac I, Xba I, Xho Iand Spe I. One of positive clones was analyzed by DNA sequencing. The specific anti-amylin clones were screened from antibody library against human amylin antigens and then the positive clones were determined by Phage-ELISA analysis. A Fab phage antibody library with 0.8×10(8); members was constructed with the efficacy of about 70%. DNA sequence analysis indicated V(H); gene belonged to V(H);3 gene family and V(λ); gene belonged to the V(λ); gene family. Using human amylin as panning antigen, specific anti-amylin Fab antibodies were enriched by screening the library for three times. Phage-ELISA assay showed the positive clones had very good specificity to amylin antigen. The successful construction of a phage antibody library and the identification of anti-amylin Fab antibodies provide a basis for further study and preparation of human anti-amylin antibodies.

  20. Computational Modelling of Large Scale Phage Production Using a Two-Stage Batch Process

    Directory of Open Access Journals (Sweden)

    Konrad Krysiak-Baltyn

    2018-04-01

    Full Text Available Cost effective and scalable methods for phage production are required to meet an increasing demand for phage, as an alternative to antibiotics. Computational models can assist the optimization of such production processes. A model is developed here that can simulate the dynamics of phage population growth and production in a two-stage, self-cycling process. The model incorporates variable infection parameters as a function of bacterial growth rate and employs ordinary differential equations, allowing application to a setup with multiple reactors. The model provides simple cost estimates as a function of key operational parameters including substrate concentration, feed volume and cycling times. For the phage and bacteria pairing examined, costs and productivity varied by three orders of magnitude, with the lowest cost found to be most sensitive to the influent substrate concentration and low level setting in the first vessel. An example case study of phage production is also presented, showing how parameter values affect the production costs and estimating production times. The approach presented is flexible and can be used to optimize phage production at laboratory or factory scale by minimizing costs or maximizing productivity.

  1. Characterization and lytic activity of methicillin-resistant Staphylococcus aureus(MRSA phages isolated from NICU

    Directory of Open Access Journals (Sweden)

    Golnar Rahimzadeh

    2016-06-01

    Full Text Available Background Methicillin-resistant Staphylococcus aureus (MRSA is a well-known pathogen that causes serious diseases in humans. As part of the efforts to control this pathogen, an isolated bacteriophage, Siphoviridae, which specifically targets Methicillin-resistant Staphylococcus aureus (MRSA, was characterized. Aims The objective of this study was to characterize of a virulent bacteriophage (Siphoviridae isolated from a NICU bathroom sink. Methods The MRSA strain was isolated from patient blood. The isolated strain was confirmed as MRSA using conventional methods. Phages were isolated from a NICU bathroom sink and activity was lytic as determined by spot test. Titer phage lysate was measured by the Double Layer Agar (DLA technique. The morphology was found with electron microscopy. The single-step growth curve was plotted. Results Electron microscopy showed the phage as a member of the family Siphoviridae, serogroup A and F. The isolated phage was capable of lytic activity against methicillin-resistant Staphylococcus aureus (MRSA strain as shown by spot test. By DLA, the titre of the phages was determined to be 10×108PFU/ml. The single-step growth curve showed that the latent period of the isolated bacteriophage was 30 min and the total number of viable progeny per infected host, burst size, was 2600 PFU/infected host. Conclusion In this study, two phages were isolated and characterized from a NICU bathroom sink, from the Siphoviridae family, which specifically targetsmethicillin-resistant Staphylococcus aureus (MRSA.

  2. Genetically Engineered Virulent Phage Banks in the Detection and Control of Emergent Pathogenic Bacteria

    Science.gov (United States)

    Blois, Hélène; Iris, François

    2010-01-01

    Natural outbreaks of multidrug-resistant microorganisms can cause widespread devastation, and several can be used or engineered as agents of bioterrorism. From a biosecurity standpoint, the capacity to detect and then efficiently control, within hours, the spread and the potential pathological effects of an emergent outbreak, for which there may be no effective antibiotics or vaccines, become key challenges that must be met. We turned to phage engineering as a potentially highly flexible and effective means to both detect and eradicate threats originating from emergent (uncharacterized) bacterial strains. To this end, we developed technologies allowing us to (1) concurrently modify multiple regions within the coding sequence of a gene while conserving intact the remainder of the gene, (2) reversibly interrupt the lytic cycle of an obligate virulent phage (T4) within its host, (3) carry out efficient insertion, by homologous recombination, of any number of engineered genes into the deactivated genomes of a T4 wild-type phage population, and (4) reactivate the lytic cycle, leading to the production of engineered infective virulent recombinant progeny. This allows the production of very large, genetically engineered lytic phage banks containing, in an E. coli host, a very wide spectrum of variants for any chosen phage-associated function, including phage host-range. Screening of such a bank should allow the rapid isolation of recombinant T4 particles capable of detecting (ie, diagnosing), infecting, and destroying hosts belonging to gram-negative bacterial species far removed from the original E. coli host. PMID:20569057

  3. Isolation and Expression of the Lysis Genes of Actinomyces naeslundii Phage Av-1

    Science.gov (United States)

    Delisle, Allan L.; Barcak, Gerard J.; Guo, Ming

    2006-01-01

    Like most gram-positive oral bacteria, Actinomyces naeslundii is resistant to salivary lysozyme and to most other lytic enzymes. We are interested in studying the lysins of phages of this important oral bacterium as potential diagnostic and therapeutic agents. To identify the Actinomyces phage genes encoding these species-specific enzymes in Escherichia coli, we constructed a new cloning vector, pAD330, that can be used to enrich for and isolate phage holin genes, which are located adjacent to the lysin genes in most phage genomes. Cloned holin insert sequences were used to design sequencing primers to identify nearby lysin genes by using whole phage DNA as the template. From partial digestions of A. naeslundii phage Av-1 genomic DNA we were able to clone, in independent experiments, inserts that complemented the defective λ holin in pAD330, as evidenced by extensive lysis after thermal induction. The DNA sequence of the inserts in these plasmids revealed that both contained the complete lysis region of Av-1, which is comprised of two holin-like genes, designated holA and holB, and an endolysin gene, designated lysA. We were able to subclone and express these genes and determine some of the functional properties of their gene products. PMID:16461656

  4. A new type of lethal short-limbed dwarfism

    International Nuclear Information System (INIS)

    Nairn, E.R.; Chapman, S.

    1989-01-01

    Details are presented of a most unusual osteo-chondrodysplasia which presents with lethal neonatal short-limbed dwarfism, defective ossification and nodular calcification with cartilage. The features resemble one case previously described in the literature. (orig.)

  5. Back to the future: revisiting HIV-1 lethal mutagenesis

    Science.gov (United States)

    Dapp, Michael J.; Patterson, Steven E.; Mansky, Louis M.

    2012-01-01

    The concept of eliminating HIV-1 infectivity by elevating the viral mutation rate was first proposed over a decade ago, even though the general concept had been conceived earlier for RNA viruses. Lethal mutagenesis was originally viewed as a novel chemotherapeutic approach for treating HIV-1 infection in which use of a viral mutagen would over multiple rounds of replication lead to the lethal accumulation of mutations, rendering the virus population non infectious – known as the slow mutation accumulation model. There have been limitations in obtaining good efficacy data with drug leads, leaving some doubt into clinical translation. More recent studies of the APOBEC3 proteins as well as new progress in the use of nucleoside analogs for inducing lethal mutagenesis have helped to refocus attention on rapid induction of HIV-1 lethal mutagenesis in a single or limited number of replication cycles leading to a rapid mutation accumulation model. PMID:23195922

  6. New type of lethal short-limbed dwarfism

    Energy Technology Data Exchange (ETDEWEB)

    Nairn, E.R.; Chapman, S.

    1989-05-01

    Details are presented of a most unusual osteo-chondrodysplasia which presents with lethal neonatal short-limbed dwarfism, defective ossification and nodular calcification with cartilage. The features resemble one case previously described in the literature.

  7. Perinatal-lethal Gaucher disease presenting as hydrops fetalis.

    Science.gov (United States)

    BenHamida, Emira; Ayadi, Imene; Ouertani, Ines; Chammem, Maroua; Bezzine, Ahlem; BenTmime, Riadh; Attia, Leila; Mrad, Ridha; Marrakchi, Zahra

    2015-01-01

    Perinatal-lethal Gaucher disease is very rare and is considered a variant of type 2 Gaucher disease that occurs in the neonatal period. The most distinct features of perinatal-lethal Gaucher disease are non-immune hydrops fetalis. Less common signs of the disease are hepatosplenomegaly, ichthyosis and arthrogryposis. We report a case of Gaucher's disease (type 2) diagnosed in a newborn who presented with Hydrops Fetalis.

  8. Conflict Without Casualties: Non-Lethal Weapons in Irregular Warfare

    Science.gov (United States)

    2007-09-01

    the body,” and the Geneva Protocol of 1925, bans the use of chemical and biological weapons .11 On 8 April 1975, President Ford issued Executive...E Funding – PE 63851M) (accessed 15 December 2006). The American Journal of Bioethics . “Medical Ethics and Non-Lethal Weapons .” Bioethics.net...CASUALTIES: NON-LETHAL WEAPONS IN IRREGULAR WARFARE by Richard L. Scott September 2007 Thesis Advisor: Robert McNab Second Reader

  9. Non-Lethal Weapons: Opportunities for R&D

    Science.gov (United States)

    2004-12-01

    during the Vietnam War. US; emulsifying agents are used in food processing, drilling fluids, cosmetics , pharmaceuticals, heavy- duty cleaners, textile...conducted in a professional manner, with no threat to public safety or the environment. 11 References [1] Fenton , G., (2001). NLW Technology Taxonomy...W.A., Mason, R.L., Collins, K.R., (2000). Non-Lethal Applicants of Slippery Substances. NDIA Non-Lethal Defense IV. [24] Fenton , G., (2000). Overview

  10. Lethal synergy involving bicyclomycin: an approach for reviving old antibiotics.

    Science.gov (United States)

    Malik, Muhammad; Li, Liping; Zhao, Xilin; Kerns, Robert J; Berger, James M; Drlica, Karl

    2014-12-01

    One way to address the growing problem of antimicrobial resistance is to revive old compounds that may have intrinsic lethal activity that is obscured by protective factors. Bicyclomycin is an old inhibitor of the Rho transcription terminator that by itself shows little rapid lethal activity. However, bicyclomycin participates in bacteriostatic synergy, which raises the possibility that conditions for lethal synergy may exist, perhaps through a suppression of protective factors. Bicyclomycin was combined with bacteriostatic inhibitors of gene expression, and bactericidal activity was measured with several cultured Gram-negative pathogens. When used alone, bicyclomycin failed to rapidly kill growing cultures of Escherichia coli; however, the additional presence of bacteriostatic concentrations of tetracycline, chloramphenicol or rifampicin led to rapid killing. Four other pathogen species, Acinetobacter baumannii, Klebsiella pneumoniae, Salmonella enterica serotype Typhimurium and Shigella dysenteriae, also exhibited enhanced killing when bicyclomycin was combined with tetracycline or rifampicin. This lethal synergy was achieved at low concentrations (slightly above the MIC) for all agents tested in combinations. Follow-up work with E. coli indicated that lethal synergy arose from a blockage of transcription elongation. Moreover, lethal synergy was reduced when bicyclomycin was added 60 min before tetracycline, suggesting that bicyclomycin induces a protective factor. The action of bicyclomycin illustrates the potential present in a largely abandoned antibacterial agent; it exhibits lethal synergy when coadministered with known, bacteriostatic inhibitors of gene expression. The identification of protective factors, which are currently uncharacterized, may reveal new ways to promote the lethal action of some old antibiotics. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved

  11. Sonographic features of lethal multiple pterygium syndrome at 14 weeks.

    Science.gov (United States)

    Chen, Min; Chan, Gavin Shueng Wai; Lee, Chin Peng; Tang, Mary Hoi Yin

    2005-06-01

    Lethal multiple pterygium syndrome is a rare inherited disorder. Previous reports suggest that the diagnosis may be based on prenatal sonographic demonstration of severe limb flexion, absence of fetal motion, and a large cystic hygroma in the second and third trimesters. We present the sonographic features and postmortem features of a fetus with lethal multiple pterygium syndrome at 13 weeks of gestation, which shows that the condition can possibly be diagnosed in the first trimester of pregnancy.

  12. Simultaneous /sup 201/Tl//sup 99m/Tc seven-pinhole tomography in acute myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Krause, T; Schuemichen, C; Fischer, R; Strauss, E; Hoffmann, G

    1986-06-01

    Combined infarction scintigraphy with /sup 201/Tl-chloride and /sup 99m/Tc-pyrophosphate (PPi) by simultaneous seven-pinhole tomography was investigated with a phantom as well as in patients. No artificial defects occurred when the collimator was centered correctly in axial position, but a very high standard of image uniformity and linearity of the gamma camera was required. Artefacts by overlying activity from the skeleton or cardiac blood pool were not observed. All 11 controls showed normal results. Despite a poor depth resolution due to limitations of the system even small areas of partially damaged myocardium could be recognized and correlated three-dimensionally. Of 24 patients with proven myocardial infarction, in 16 both a positive (/sup 99m/Tc-PPi) and a negative (/sup 201/Tl) image was obtained in congruence with the necrosis. 8 patients (33%) showed discordant results providing however additional information on the nature and extent of the necrosis. 4 out of 6 non-transmural infarctions seen by tomography had been suspected clinically.

  13. Varenicline increases in vivo striatal dopamine D2/3 receptor binding: an ultra-high-resolution pinhole [123I]IBZM SPECT study in rats

    International Nuclear Information System (INIS)

    Crunelle, Cleo L.; Wit, Tim C. de; Bruin, Kora de; Ramakers, Ruud M.; Have, Frans van der; Beekman, Freek J.; Brink, Wim van den; Booij, Jan

    2012-01-01

    Introduction: Ex vivo storage phosphor imaging rat studies reported increased brain dopamine D 2/3 receptor (DRD 2/3 ) availability following treatment with varenicline, a nicotinergic drug. However, ex vivo studies can only be performed using cross-sectional designs. Small-animal imaging offers the opportunity to perform serial assessments. We evaluated whether high-resolution pinhole single photon emission computed tomography (SPECT) imaging in rats was able to reproduce previous ex vivo findings. Methods: Rats were imaged for baseline striatal DRD 2/3 availability using ultra-high-resolution pinhole SPECT (U-SPECT-II) and [ 123 I]IBZM as a radiotracer, and randomized to varenicline (n=7; 2 mg/kg) or saline (n=7). Following 2 weeks of treatment, a second scan was acquired. Results: Significantly increased striatal DRD 2/3 availability was found following varenicline treatment compared to saline (time⁎treatment effect): posttreatment difference in binding potential between groups corrected for initial baseline differences was 2.039 (P=.022), indicating a large effect size (d=1.48). Conclusions: Ultra-high-resolution pinhole SPECT can be used to assess varenicline-induced changes in DRD 2/3 availability in small laboratory animals over time. Future small-animal studies should include imaging techniques to enable repeated within-subjects measurements and reduce the amount of animals.

  14. Phage Fab Display Selection In Vitro and In Vivo: Novel Means to Identify New Breast Cancer Avid Compounds

    National Research Council Canada - National Science Library

    Meighan, Mark

    2001-01-01

    .... In this annual report we present preliminary results on the isolation of antibody fragments (Fabs), isolated from phage display libraries, when affinity selected against breast cancer cell lines...

  15. Two Novel Myoviruses from the North of Iraq Reveal Insights into Clostridium difficile Phage Diversity and Biology

    Directory of Open Access Journals (Sweden)

    Srwa J. Rashid

    2016-11-01

    Full Text Available Bacteriophages (phages are increasingly being explored as therapeutic agents to combat bacterial diseases, including Clostridium difficile infections. Therapeutic phages need to be able to efficiently target and kill a wide range of clinically relevant strains. While many phage groups have yet to be investigated in detail, those with new and useful properties can potentially be identified when phages from newly studied geographies are characterised. Here, we report the isolation of C. difficile phages from soil samples from the north of Iraq. Two myoviruses, CDKM15 and CDKM9, were selected for detailed sequence analysis on the basis of their broad and potentially useful host range. CDKM9 infects 25/80 strains from 12/20 C. difficile ribotypes, and CDKM15 infects 20/80 strains from 9/20 ribotypes. Both phages can infect the clinically relevant ribotypes R027 and R001. Phylogenetic analysis based on whole genome sequencing revealed that the phages are genetically distinct from each other but closely related to other long-tailed myoviruses. A comparative genomic analysis revealed key differences in the genes predicted to encode for proteins involved in bacterial infection. Notably, CDKM15 carries a clustered regularly interspaced short palindromic repeat (CRISPR array with spacers that are homologous to sequences in the CDKM9 genome and of phages from diverse localities. The findings presented suggest a possible shared evolutionary past for these phages and provides evidence of their widespread dispersal.

  16. Recent Trends in Salmonella Outbreaks and Emerging Technology for Biocontrol of Salmonella Using Phages in Foods: A Review.

    Science.gov (United States)

    Oh, Jun-Hyun; Park, Mi-Kyung

    2017-12-28

    Salmonella is one of the principal causes of foodborne outbreaks. As traditional control methods have shown less efficacy against emerging Salmonella serotypes or antimicrobialresistant Salmonella , new approaches have been attempted. The use of lytic phages for the biocontrol of Salmonella in the food industry has become an attractive method owing to the many advantages offered by the use of phages as biocontrol agents. Phages are natural alternatives to traditional antimicrobial agents; they have proven effective in the control of bacterial pathogens in the food industry, which has led to the development of different phage products. The treatment with specific phages in the food industry can prevent the decay of products and the spread of bacterial diseases, and ultimately promotes safe environments for animal and plant food production, processing, and handling. After an extensive investigation of the current literature, this review focuses predominantly on the efficacy of phages for the successful control of Salmonella spp. in foods. This review also addresses the current knowledge on the pathogenic characteristics of Salmonella , the prevalence of emerging Salmonella outbreaks, the isolation and characterization of Salmonella -specific phages, the effectiveness of Salmonella -specific phages as biocontrol agents, and the prospective use of Salmonella -specific phages in the food industry.

  17. Potential effect of some environmental factors on the phage removal during wastewater treatment. Study in vitro

    International Nuclear Information System (INIS)

    Benhyahya, M.; Bohatier, J.; Laveran, H.; Ettayebi, M.; Senaud, J.

    2000-01-01

    Great quantities of enteric viruses and bacteriophages are included in wastewaters. They represent a contamination risk of natural water systems. But this viral burden is greatly reduced in the sewage treatment plants by the combined action of numerous environmental factors. To study water quality, some groups of bacteriophages as E. coli phages and Bacteroides fragilis phages have been proposed as model viruses. On an other hand, somatic and, in particular, F-specific coliphages have several morphological, structural and chemical composition ressemblances with the enteric viruses. Two different bacteriophages (øX-174 and MS2) were used as virus models in this in vitro study to evaluate the viral adsorption on suspended clay particles. Distilled sterile water was used as reactional medium to avoid the possible interactions with the considered substrates, the kaolinite (K) and the montmorillonite (M). Phage behaviour in the water and in the recommended diluent for phages, the saline peptone, was first compared. K and M suspensions were used at 300 mg/l for a contact time of 5, 30 and 60 min. In other series K and M suspensions were prepared at 600, 300 and 100 mg/l then used to determine the phage adsorption capacity in a fixed time 30 min. Results show that the phage titers for all samples were constant in the organic diluent. They were lower in the distilled sterile water and decrease with the time. Distilled water favours most likely the grouping of virions and leads aggregates formation. The adsorption of øX-174 and MS2 onto K or M particles was instantaneous and independent of the duration contact. The clay concentration had a slight significant influence on the phage adsorption rate. Using the same phages we have studied, in a second stage, the potential effect of the dissolved matters in a filtered polluted effluent, that of sunlight radiations and that of the protozoan Tetrahymena pyriformis on the phage removal. No soon significant phage inactivation was

  18. A novel Pseudomonas aeruginosa bacteriophage, Ab31, a chimera formed from temperate phage PAJU2 and P. putida lytic phage AF: characteristics and mechanism of bacterial resistance.

    Directory of Open Access Journals (Sweden)

    Libera Latino

    Full Text Available A novel temperate bacteriophage of Pseudomonas aeruginosa, phage vB_PaeP_Tr60_Ab31 (alias Ab31 is described. Its genome is composed of structural genes related to those of lytic P. putida phage AF, and regulatory genes similar to those of temperate phage PAJU2. The virion structure resembles that of phage AF and other lytic Podoviridae (S. enterica Epsilon 15 and E. coli phiv10 with similar tail spikes. Ab31 was able to infect P. aeruginosa strain PA14 and two genetically related strains called Tr60 and Tr162, out of 35 diverse strains from cystic fibrosis patients. Analysis of resistant host variants revealed different phenotypes, including induction of pigment and alginate overproduction. Whole genome sequencing of resistant variants highlighted the existence of a large deletion of 234 kbp in two strains, encompassing a cluster of genes required for the production of CupA fimbriae. Stable lysogens formed by Ab31 in strain Tr60, permitted the identification of the insertion site. During colonization of the lung in cystic fibrosis patients, P. aeruginosa adapts by modifying its genome. We suggest that bacteriophages such as Ab31 may play an important role in this adaptation by selecting for bacterial characteristics that favor persistence of bacteria in the lung.

  19. Phages of lactic acid bacteria: The role of genetics in understanding phage-host interactions and their co-evolutionary processes

    International Nuclear Information System (INIS)

    Mahony, Jennifer; Ainsworth, Stuart; Stockdale, Stephen; Sinderen, Douwe van

    2012-01-01

    Dairy fermentations are among the oldest food processing applications, aimed at preservation and shelf-life extension through the use of lactic acid bacteria (LAB) starter cultures, in particular strains of Lactococcus lactis, Streptococcus thermophilus, Lactobacillus spp. and Leuconostoc spp. Traditionally this was performed by continuous passaging of undefined cultures from a finished fermentation to initiate the next fermentation. More recently, consumer demands on consistent and desired flavours and textures of dairy products have led to a more defined approach to such processes. Dairy (starter) companies have responded to the need to define the nature and complexity of the starter culture mixes, and dairy fermentations are now frequently based on defined starter cultures of low complexity, where each starter component imparts specific technological properties that are desirable to the product. Both mixed and defined starter culture approaches create the perfect environment for the proliferation of (bacterio)phages capable of infecting these LAB. The repeated use of the same starter cultures in a single plant, coupled to the drive towards higher and consistent production levels, increases the risk and negative impact of phage infection. In this review we will discuss recent advances in tracking the adaptation of phages to the dairy industry, the advances in understanding LAB phage-host interactions, including evolutionary and genomic aspects.

  20. Phages of lactic acid bacteria: The role of genetics in understanding phage-host interactions and their co-evolutionary processes

    Energy Technology Data Exchange (ETDEWEB)

    Mahony, Jennifer, E-mail: j.mahony@ucc.ie [Department of Microbiology, University College Cork, Western Road, Cork (Ireland); Ainsworth, Stuart; Stockdale, Stephen [Department of Microbiology, University College Cork, Western Road, Cork (Ireland); Sinderen, Douwe van, E-mail: d.vansinderen@ucc.ie [Department of Microbiology, University College Cork, Western Road, Cork (Ireland); Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Western Road, Cork (Ireland)

    2012-12-20

    Dairy fermentations are among the oldest food processing applications, aimed at preservation and shelf-life extension through the use of lactic acid bacteria (LAB) starter cultures, in particular strains of Lactococcus lactis, Streptococcus thermophilus, Lactobacillus spp. and Leuconostoc spp. Traditionally this was performed by continuous passaging of undefined cultures from a finished fermentation to initiate the next fermentation. More recently, consumer demands on consistent and desired flavours and textures of dairy products have led to a more defined approach to such processes. Dairy (starter) companies have responded to the need to define the nature and complexity of the starter culture mixes, and dairy fermentations are now frequently based on defined starter cultures of low complexity, where each starter component imparts specific technological properties that are desirable to the product. Both mixed and defined starter culture approaches create the perfect environment for the proliferation of (bacterio)phages capable of infecting these LAB. The repeated use of the same starter cultures in a single plant, coupled to the drive towards higher and consistent production levels, increases the risk and negative impact of phage infection. In this review we will discuss recent advances in tracking the adaptation of phages to the dairy industry, the advances in understanding LAB phage-host interactions, including evolutionary and genomic aspects.

  1. Proposed Ancestors of Phage Nucleic Acid Packaging Motors (and Cells

    Directory of Open Access Journals (Sweden)

    Philip Serwer

    2011-07-01

    Full Text Available I present a hypothesis that begins with the proposal that abiotic ancestors of phage RNA and DNA packaging systems (and cells include mobile shells with an internal, molecule-transporting cavity. The foundations of this hypothesis include the conjecture that current nucleic acid packaging systems have imprints from abiotic ancestors. The abiotic shells (1 initially imbibe and later also bind and transport organic molecules, thereby providing a means for producing molecular interactions that are links in the chain of events that produces ancestors to the first molecules that are both information carrying and enzymatically active, and (2 are subsequently scaffolds on which proteins assemble to form ancestors common to both shells of viral capsids and cell membranes. Emergence of cells occurs via aggregation and merger of shells and internal contents. The hypothesis continues by using proposed imprints of abiotic and biotic ancestors to deduce an ancestral thermal ratchet-based DNA packaging motor that subsequently evolves to integrate a DNA packaging ATPase that provides a power stroke.

  2. Antibody phage display applications for nuclear medicine imaging and therapy

    International Nuclear Information System (INIS)

    Winthrop, M.D.; Denardo, G.L.; Denardo, S.J.

    2000-01-01

    Antibody-based constructs genetically engineered from genes of diverse origin provide a remarkable opportunity to develop functional molecular imaging techniques and specific molecular targeted radionuclide therapies. Phage display libraries of antibody fragment genes can be used to select antibody-based constructs that bind any chosen epitope. A large naive human antibody-based library was used to illustrate binding of antibody constructs to a variety of common and unique antigens. Antibody-based libraries from hybridoma cells, lymphocytes from immunized humans or from mice and human antibody repertoires produced in transgenic mice have also been described. Several orders of magnitude of affinity enhancement can be achieved by random or site specific mutations of the selected binding peptide domains of the scFv. Affinities (K d ) as high as 10 - 11 M (10 pM) for affinity-matured scFv have been documented. Such gene libraries thus offer an almost limitless variety of antibody-based molecular binding peptide modules that can be used in creative ways for the construction of new targeting agents for functional or molecular imaging and therapy

  3. Genome of a SAR116 bacteriophage shows the prevalence of this phage type in the oceans.

    Science.gov (United States)

    Kang, Ilnam; Oh, Hyun-Myung; Kang, Dongmin; Cho, Jang-Cheon

    2013-07-23

    The abundance, genetic diversity, and crucial ecological and evolutionary roles of marine phages have prompted a large number of metagenomic studies. However, obtaining a thorough understanding of marine phages has been hampered by the low number of phage isolates infecting major bacterial groups other than cyanophages and pelagiphages. Therefore, there is an urgent requirement for the isolation of phages that infect abundant marine bacterial groups. In this study, we isolated and characterized HMO-2011, a phage infecting a bacterium of the SAR116 clade, one of the most abundant marine bacterial lineages. HMO-2011, which infects "Candidatus Puniceispirillum marinum" strain IMCC1322, has an ~55-kb dsDNA genome that harbors many genes with novel features rarely found in cultured organisms, including genes encoding a DNA polymerase with a partial DnaJ central domain and an atypical methanesulfonate monooxygenase. Furthermore, homologs of nearly all HMO-2011 genes were predominantly found in marine metagenomes rather than cultured organisms, suggesting the novelty of HMO-2011 and the prevalence of this phage type in the oceans. A significant number of the viral metagenome sequences obtained from the ocean surface were best assigned to the HMO-2011 genome. The number of reads assigned to HMO-2011 accounted for 10.3%-25.3% of the total reads assigned to viruses in seven viromes from the Pacific and Indian Oceans, making the HMO-2011 genome the most or second-most frequently assigned viral genome. Given its ability to infect the abundant SAR116 clade and its widespread distribution, Puniceispirillum phage HMO-2011 could be an important resource for marine virus research.

  4. Commensal E. coli Stx2 lysogens produce high levels of phages after spontaneous prophage induction

    Directory of Open Access Journals (Sweden)

    Hildegunn eIversen

    2015-02-01

    Full Text Available Enterohemorrhagic E. coli (EHEC is a food-borne pathogen that causes disease ranging from uncomplicated diarrhea to life-threatening hemolytic uremic syndrome (HUS and nervous system complications. Shiga toxin 2 (Stx2 is the major virulence factor of EHEC and is critical for development of HUS. The genes encoding Stx2 are carried by lambdoid bacteriophages and the toxin production is tightly linked to the production of phages during lytic cycle. It has previously been suggested that commensal E. coli could amplify the production of Stx2-phages and contribute to the severity of disease. In this study we examined the susceptibility of commensal E. coli strains to the Stx2-converting phage ϕ734, isolated from a highly virulent EHEC O103:H25 (NIPH-11060424. Among 38 commensal E. coli strains from healthy children below five years, 15 were lysogenized by the ϕ734 phage, whereas lytic infection was not observed. Three of the commensal E. coli ϕ734 lysogens were tested for stability, and appeared stable and retained the phage for at least 10 cultural passages. When induced to enter lytic cycle by H2O2 treatment, 8 out of 13 commensal lysogens produced more ϕ734 phages than NIPH-11060424. Strikingly, five of them even spontaneously (non-induced produced higher levels of phage than the H2O2 induced NIPH-11060424. An especially high frequency of HUS (60% was seen among children infected by NIPH-11060424 during the outbreak in 2006. Based on our findings, a high Stx2 production by commensal E. coli lysogens cannot be ruled out as a contributor to the high frequency of HUS during this outbreak.

  5. Thermal-Stability and Reconstitution Ability of Listeria Phages P100 and A511

    Directory of Open Access Journals (Sweden)

    Hanie Ahmadi

    2017-12-01

    Full Text Available The study evaluated the thermal-stability of Listeria phages P100 and A511 at temperatures simulating the preparation of ready-to-eat meats. The phage infectivity after heating to 71°C and holding for a minimum of 30 s, before eventually cooling to 4°C were examined. Higher temperatures of 75, 80, and 85°C were also tested to evaluate their effect on phages thermal-stability. This study found that despite minor differences in the amino acid sequences of their structural proteins, the two phages responded differently to high temperatures. P100 activity declined at least 10 log (PFU mL-1 with exposure to 71°C (30 s and falling below the limit of detection (1 log PFU mL-1 while, A511 dropped from 108 to 105 PFU mL-1. Cooling resulted in partial reconstitution of P100 phage particles to 103 PFU mL-1. Exposure to 75°C (30 s abolished A511 activity (8 log PFU mL-1 and both phages showed reconstitution during cooling phase after exposure to 75°C. P100 exhibited reconstitution after treatment at 80°C (30 s, conversely A511 showed no reconstitution activity. Heating P100 to 85°C abolished the reconstitution potential. Substantial differences were found in thermal-stability and reconstitution of the examined phages showing A511 to be more thermo-stable than P100, while P100 exhibited reconstitution during cooling after treatment at 80°C which was absent in A511. The differences in predicted melting temperatures of structural proteins of P100 and A511 were consistent with the observed differences in thermal stability and morphological changes observed with transmission electron microscopy.

  6. Phage annealing proteins promote oligonucleotide-directed mutagenesis in Escherichia coli and mouse ES cells

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    Muyrers Joep PP

    2003-01-01

    Full Text Available Abstract Background The phage protein pairs, RecE/RecT from Rac or Redα/Redβ from λ, initiate efficient double strand break repair (DSBR in Escherichia coli that has proven very useful for DNA engineering. These phage pairs initiate DSBR either by annealing or by another mechanism that is not defined. Results Here we report that these proteins also mediate single strand oligonucleotide repair (ssOR at high efficiencies. The ssOR activity, unlike DSBR, does not require a phage exonuclease (RecE or Redα but only requires a phage annealing protein (RecT or Redβ. Notably, the P22 phage annealing protein Erf, which does not mediate the same DSBR reactions, also delivers ssOR activity. By altering aspects of the oligonucleotides, we document length and design parameters that affect ssOR efficiency to show a simple relationship to homologies either side of the repair site. Notably, ssOR shows strand bias. Oligonucleotides that can prime lagging strand replication deliver more ssOR than their leading complements. This suggests a model in which the annealing proteins hybridize the oligonucleotides to single stranded regions near the replication fork. We also show that ssOR is a highly efficient way to engineer BACs and can be detected in a eukaryotic cell upon expression of a phage annealing protein. Conclusion Phage annealing proteins can initiate the recombination of single stranded oligonucleotides into endogenous targets in Escherichia coli at very high efficiencies. This expands the repertoire of useful DNA engineering strategies, shows promise for applications in eukaryotic cells, and has implications for the unanswered questions regarding DSBR mediated by RecE/RecT and Redα/Redβ.

  7. Temperate Streptococcus thermophilus phages expressing superinfection exclusion proteins of the Ltp type

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    Yahya eAli

    2014-03-01

    Full Text Available Lipoprotein Ltp encoded by temperate Streptococcus thermophilus phage TP-J34 is the prototype of the wide-spread family of host cell surface-exposed lipoproteins involved in superinfection exclusion. When screening for other S. thermophilus phages expressing this type of lipoprotein, three temperate phages - TP-EW, TP-DSM20617 and TP-778 - were isolated. In this communication we present the total nucleotide sequences of TP-J34 and TP-778L. For TP-EW, a phage almost identical to TP-J34, besides the ltp gene only the two regions of deviation from TP-J34 DNA were analyzed: the gene encoding the tail protein causing an assembly defect in TP-J34 and the gene encoding the lysin, which in TP-EW contains an intron. For TP-DSM20617 only the sequence of the lysogeny module containing the ltp gene was determined. The region showed high homology to the same region of TP-778. For TP-778 we could show that absence of the attR region resulted in aberrant excision of phage DNA. The amino acid sequence of mature LtpTP-EW was shown to be identical to that of mature LtpTP-J34, whereas the amino acid sequence of mature LtpTP-778 was shown to differ from mature LtpTP-J34 in eight amino acid positions. LtpTP-DSM20617 was shown to differ from LtpTP-778 in just one amino acid position. In contrast to LtpTP-J34, LtpTP-778 did not affect infection of lactococcal phage P008 instead increased activity against phage P001 was noticed.

  8. Construction of genetically engineered M13K07 helper phage for simultaneous phage display of gold binding peptide 1 and nuclear matrix protein 22 ScFv antibody.

    Science.gov (United States)

    Fatemi, Farnaz; Amini, Seyed Mohammad; Kharrazi, Sharmin; Rasaee, Mohammad Javad; Mazlomi, Mohammad Ali; Asadi-Ghalehni, Majid; Rajabibazl, Masoumeh; Sadroddiny, Esmaeil

    2017-11-01

    The most common techniques of antibody phage display are based on the use of M13 filamentous bacteriophages. This study introduces a new genetically engineered M13K07 helper phage displaying multiple copies of a known gold binding peptide on p8 coat proteins. The recombinant helper phages were used to rescue a phagemid vector encoding the p3 coat protein fused to the nuclear matrix protein 22 (NMP22) ScFv antibody. Transmission electron microscopy (TEM), UV-vis absorbance spectroscopy, and field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray spectroscopy (EDX) analysis revealed that the expression of gold binding peptide 1 (GBP1) on major coat protein p8 significantly enhances the gold-binding affinity of M13 phages. The recombinant bacteriophages at concentrations above 5×10 4 pfu/ml red-shifted the UV-vis absorbance spectra of gold nanoparticles (AuNPs); however, the surface plasmon resonance of gold nanoparticles was not changed by the wild type bacteriophages at concentrations up to 10 12 pfu/ml. The phage ELISA assay demonstrated the high affinity binding of bifunctional bacteriophages to NMP22 antigen at concentrations of 10 5 and 10 6 pfu/ml. Thus, the p3 end of the bifunctional bacteriophages would be able to bind to specific target antigen, while the AuNPs were assembled along the coat of virus for signal generation. Our results indicated that the complex of antigen-bacteriophages lead to UV-vis spectral changes of AuNPs and NMP22 antigen in concentration range of 10-80μg/ml can be detected by bifunctional bacteriophages at concentration of 10 4 pfu/ml. The ability of bifunctional bacteriophages to bind to antigen and generate signal at the same time, makes this approach applicable for identifying different antigens in immunoassay techniques. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Phage type and sensitivity to antibiotics of Staphylococcus aureus film-forming strains isolated from airway mucosa

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    O. S. Voronkova

    2014-10-01

    Full Text Available Today film-forming strains of bacteria play very important role in clinical pathology. Staphylococci are ones of most dangerous of them. This bacteria can determine different pathological processes, for example, complication of airway mucosa. The ability to form a biofilm is one of the main properties of nosocomial strains. These strains should be monitored and their carriers are to be properly treated. To determine the origin of staphylococci strains we used bacteriophages from the International kit. The aim of research was to determine the phage type of staphylococci film-forming strains, that were isolated from naso-pharingial mucosa. Phage typing has been carried out for 16 film-forming strains of S. aureus. To solve this problem, we used the International phage kit by Fisher’s method. As a result, sensitivity to phages from the International kit showed 53.8% of studied strains of S. aureus. 64.3% of sensitivity strains were lysed by one of the phage, 21.4% – were by two of the phages, 14.3% – by three of the phages. Isolates were sensitive to phages: 81 – 42.9%, 75 – 35.7%, 28.6% were sensitive to phages 47 and 53. All cases of detection of sensitivity to phage 47 coincided with the ability to form biofilm. Among non-film-forming strains there was no sensitive strains for this phage. Film-forming strains resist to erythromycin (62.5%, ciprofloxacin (43.8%, gentamicin (56.3%, tetracycline (87.5%, amoxicillin (93.8%, and cefuroxime (37.5%. All cases of sensitivity to phage 47 coincided with resistance to erythromycin, amoxicillin and tetracycline. For two of these strains, we also defined resistance to gentamicin and for one of them – to ciprofloxacin. Results of research allowed to relate the bacterial cultures for determining the type. This may have implications for studying of film-forming ability, because surface structures of bacterial cell take place in this process. Belonging of an isolate to specific phage type may

  10. Phage or foe: an insight into the impact of viral predation on microbial communities.

    Science.gov (United States)

    Fernández, Lucía; Rodríguez, Ana; García, Pilar

    2018-05-01

    Since their discovery, bacteriophages have been traditionally regarded as the natural enemies of bacteria. However, recent advances in molecular biology techniques, especially data from "omics" analyses, have revealed that the interplay between bacterial viruses and their hosts is far more intricate than initially thought. On the one hand, we have become more aware of the impact of viral predation on the composition and genetic makeup of microbial communities thanks to genomic and metagenomic approaches. Moreover, data obtained from transcriptomic, proteomic, and metabolomic studies have shown that responses to phage predation are complex and diverse, varying greatly depending on the bacterial host, phage, and multiplicity of infection. Interestingly, phage exposure may alter different phenotypes, including virulence and biofilm formation. The complexity of the interactions between microbes and their viral predators is also evidenced by the link between quorum-sensing signaling pathways and bacteriophage resistance. Overall, new data increasingly suggests that both temperate and virulent phages have a positive effect on the evolution and adaptation of microbial populations. From this perspective, further research is still necessary to fully understand the interactions between phage and host under conditions that allow co-existence of both populations, reflecting more accurately the dynamics in natural microbial communities.

  11. Assessment of the microscreen phage-induction assay for screening hazardous wastes (1989)

    Energy Technology Data Exchange (ETDEWEB)

    Houk, V.S.; DeMarini, D.M.

    1989-01-01

    The Microscreen phage-induction assay, which quantitatively measures the induction of prophage Lambda in Escherichia coli WP2s(Lambda), was used to test 14 crude (unfractionated) hazardous industrial-waste samples for genotoxic activity in the presence and absence of metabolic activation. Eleven of the 14 wastes induced prophage, and induction was observed at concentrations as low as 0.4 picograms per ml. Comparisons of the mutagenic activity of these waste samples in Salmonella and their ability to induce prophage Lambda indicate that the phage-induction assay was a more-sensitive indicator of genetic damage for this group of wastes. All but one of the wastes that were mutagenic to Salmonella were detected by the phage-induction assay, and 5 wastes not mutagenic to Salmonella were genetically active in the phage assay. The enhanced ability of the phage-induction assay to detect genotoxic activity may be related to the constituents comprising these waste samples. Partial chemical characterizations of the wastes showed high concentrations of carcinogenic metals, solvents, and chlorinated compounds, most of which are detected poorly by the Salmonella assay.

  12. Corruption of phage display libraries by target-unrelated clones: diagnosis and countermeasures.

    Science.gov (United States)

    Thomas, William D; Golomb, Miriam; Smith, George P

    2010-12-15

    Phage display is used to discover peptides or proteins with a desired target property-most often, affinity for a target selector molecule. Libraries of phage clones displaying diverse surface peptides are subject to a selection process designed to enrich for the target behavior and subsequently propagated to restore phage numbers. A recurrent problem is enrichment of clones, called target-unrelated phages or peptides (TUPs), that lack the target behavior. Many TUPs are propagation related; they have mutations conferring a growth advantage and are enriched during the propagations accompanying selection. Unlike other filamentous phage libraries, fd-tet-based libraries are relatively resistant to propagation-related TUP corruption. Their minus-strand origin is disrupted by a large cassette that simultaneously confers resistance to tetracycline and imposes a rate-limiting growth defect that cannot be bypassed with simple mutations. Nonetheless, a new type of propagation-related TUP emerged in the output of in vivo selections from an fd-tet library. The founding clone had a complex rearrangement that restored the minus-strand origin while retaining tetracycline resistance. The rearrangement involved two recombination events, one with a contaminant having a wild-type minus-strand origin. The founder's infectivity advantage spread by simple recombination to clones displaying different peptides. We propose measures for minimizing TUP corruption. Copyright © 2010 Elsevier Inc. All rights reserved.

  13. Corruption of phage-display libraries by target-unrelated clones: Diagnosis and countermeasures

    Science.gov (United States)

    Thomas, William D.; Golomb, Miriam; Smith, George P.

    2010-01-01

    Phage display is used to discover peptides or proteins with a desired target property—most often, affinity for a target selector molecule. Libraries of phage clones displaying diverse surface peptides are subject to a selection process designed to enrich for the target behavior, and subsequently propagated to restore phage numbers. A recurrent problem is enrichment of clones, called target-unrelated phage (TUPs), that lack the target behavior. Many TUPs are propagation-related; they have mutations conferring a growth advantage, and are enriched during the propagations accompanying selection. Unlike other filamentous phage libraries, fd-tet-based libraries are relatively resistant to propagation-related TUP corruption. Their minus strand origin is disrupted by a large cassette that simultaneously confers resistance to tetracycline and imposes a rate-limiting growth defect that cannot be bypassed with simple mutations. Nonetheless, a new type of propagation-related TUP emerged in the output of in vivo selections from an fd-tet library. The founding clone had a complex rearrangement that restored the minus strand origin while retaining tetracycline resistance. The rearrangement involved two recombination events, one with a contaminant having a wild-type minus strand origin. The founder’s infectivity advantage spread by simple recombination to clones displaying different peptides. We propose measures for minimizing TUP corruption. PMID:20692225

  14. Beyond Helper Phage: Using "Helper Cells" to Select Peptide Affinity Ligands.

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    M Lisa Phipps

    Full Text Available Peptides are important affinity ligands for microscopy, biosensing, and targeted delivery. However, because they can have low affinity for their targets, their selection from large naïve libraries can be challenging. When selecting peptidic ligands from display libraries, it is important to: 1 ensure efficient display; 2 maximize the ability to select high affinity ligands; and 3 minimize the effect of the display context on binding. The "helper cell" packaging system has been described as a tool to produce filamentous phage particles based on phagemid constructs with varying display levels, while remaining free of helper phage contamination. Here we report on the first use of this system for peptide display, including the systematic characterization and optimization of helper cells, their inefficient use in antibody display and their use in creating and selecting from a set of phage display peptide libraries. Our libraries were analyzed with unprecedented precision by standard or deep sequencing, and shown to be superior in quality than commercial gold standards. Using our helper cell libraries, we have obtained ligands recognizing Yersinia pestis surface antigen F1V and L-glutamine-binding periplasmic protein QBP. In the latter case, unlike any of the peptide library selections described so far, we used a combination of phage and yeast display to select intriguing peptide ligands. Based on the success of our selections we believe that peptide libraries obtained with helper cells are not only suitable, but preferable to traditional phage display libraries for selection of peptidic ligands.

  15. Reversing bacterial resistance to antibiotics by phage-mediated delivery of dominant sensitive genes.

    Science.gov (United States)

    Edgar, Rotem; Friedman, Nir; Molshanski-Mor, Shahar; Qimron, Udi

    2012-02-01

    Pathogen resistance to antibiotics is a rapidly growing problem, leading to an urgent need for novel antimicrobial agents. Unfortunately, development of new antibiotics faces numerous obstacles, and a method that resensitizes pathogens to approved antibiotics therefore holds key advantages. We present a proof of principle for a system that restores antibiotic efficiency by reversing pathogen resistance. This system uses temperate phages to introduce, by lysogenization, the genes rpsL and gyrA conferring sensitivity in a dominant fashion to two antibiotics, streptomycin and nalidixic acid, respectively. Unique selective pressure is generated to enrich for bacteria that harbor the phages carrying the sensitizing constructs. This selection pressure is based on a toxic compound, tellurite, and therefore does not forfeit any antibiotic for the sensitization procedure. We further demonstrate a possible way of reducing undesirable recombination events by synthesizing dominant sensitive genes with major barriers to homologous recombination. Such synthesis does not significantly reduce the gene's sensitization ability. Unlike conventional bacteriophage therapy, the system does not rely on the phage's ability to kill pathogens in the infected host, but instead, on its ability to deliver genetic constructs into the bacteria and thus render them sensitive to antibiotics prior to host infection. We believe that transfer of the sensitizing cassette by the constructed phage will significantly enrich for antibiotic-treatable pathogens on hospital surfaces. Broad usage of the proposed system, in contrast to antibiotics and phage therapy, will potentially change the nature of nosocomial infections toward being more susceptible to antibiotics rather than more resistant.

  16. Development of anti-infectives using phage display: biological agents against bacteria, viruses, and parasites.

    Science.gov (United States)

    Huang, Johnny X; Bishop-Hurley, Sharon L; Cooper, Matthew A

    2012-09-01

    The vast majority of anti-infective therapeutics on the market or in development are small molecules; however, there is now a nascent pipeline of biological agents in development. Until recently, phage display technologies were used mainly to produce monoclonal antibodies (MAbs) targeted against cancer or inflammatory disease targets. Patent disputes impeded broad use of these methods and contributed to the dearth of candidates in the clinic during the 1990s. Today, however, phage display is recognized as a powerful tool for selecting novel peptides and antibodies that can bind to a wide range of antigens, ranging from whole cells to proteins and lipid targets. In this review, we highlight research that exploits phage display technology as a means of discovering novel therapeutics against infectious diseases, with a focus on antimicrobial peptides and antibodies in clinical or preclinical development. We discuss the different strategies and methods used to derive, select, and develop anti-infectives from phage display libraries and then highlight case studies of drug candidates in the process of development and commercialization. Advances in screening, manufacturing, and humanization technologies now mean that phage display can make a significant contribution in the fight against clinically important pathogens.

  17. Modular architecture of the T4 phage superfamily: A conserved core genome and a plastic periphery

    International Nuclear Information System (INIS)

    Comeau, Andre M.; Bertrand, Claire; Letarov, Andrei; Tetart, Francoise; Krisch, H.M.

    2007-01-01

    Among the most numerous objects in the biosphere, phages show enormous diversity in morphology and genetic content. We have sequenced 7 T4-like phages and compared their genome architecture. All seven phages share a core genome with T4 that is interrupted by several hyperplastic regions (HPRs) where most of their divergence occurs. The core primarily includes homologues of essential T4 genes, such as the virion structure and DNA replication genes. In contrast, the HPRs contain mostly novel genes of unknown function and origin. A few of the HPR genes that can be assigned putative functions, such as a series of novel Internal Proteins, are implicated in phage adaptation to the host. Thus, the T4-like genome appears to be partitioned into discrete segments that fulfil different functions and behave differently in evolution. Such partitioning may be critical for these large and complex phages to maintain their flexibility, while simultaneously allowing them to conserve their highly successful virion design and mode of replication

  18. Phages can constrain protist predation-driven attenuation of Pseudomonas aeruginosa virulence in multienemy communities

    Science.gov (United States)

    Friman, Ville-Petri; Buckling, Angus

    2014-01-01

    The coincidental theory of virulence predicts that bacterial pathogenicity could be a by-product of selection by natural enemies in environmental reservoirs. However, current results are ambiguous and the simultaneous impact of multiple ubiquitous enemies, protists and phages on virulence evolution has not been investigated previously. Here we tested experimentally how Tetrahymena thermophila protist predation and PNM phage parasitism (bacteria-specific virus) alone and together affect the evolution of Pseudomonas aeruginosa PAO1 virulence, measured in wax moth larvae. Protist predation selected for small colony types, both in the absence and presence of phage, which showed decreased edibility to protists, reduced growth in the absence of enemies and attenuated virulence. Although phage selection alone did not affect the bacterial phenotype, it weakened protist-driven antipredatory defence (biofilm formation), its associated pleiotropic growth cost and the correlated reduction in virulence. These results suggest that protist selection can be a strong coincidental driver of attenuated bacterial virulence, and that phages can constrain this effect owing to effects on population dynamics and conflicting selection pressures. Attempting to define causal links such as these might help us to predict the cold and hot spots of coincidental virulence evolution on the basis of microbial community composition of environmental reservoirs. PMID:24671085

  19. Bacteria between protists and phages: from antipredation strategies to the evolution of pathogenicity.

    Science.gov (United States)

    Brüssow, Harald

    2007-08-01

    Bacteriophages and protists are major causes of bacterial mortality. Genomics suggests that phages evolved well before eukaryotic protists. Bacteria were thus initially only confronted with phage predators. When protists evolved, bacteria were caught between two types of predators. One successful antigrazing strategy of bacteria was the elaboration of toxins that would kill the grazer. The released cell content would feed bystander bacteria. I suggest here that, to fight grazing protists, bacteria teamed up with those phage predators that concluded at least a temporary truce with them in the form of lysogeny. Lysogeny was perhaps initially a resource management strategy of phages that could not maintain infection chains. Subsequently, lysogeny might have evolved into a bacterium-prophage coalition attacking protists, which became a food source for them. When protists evolved into multicellular animals, the lysogenic bacteria tracked their evolving food source. This hypothesis could explain why a frequent scheme of bacterial pathogenicity is the survival in phagocytes, why a significant fraction of bacterial pathogens have prophage-encoded virulence genes, and why some virulence factors of animal pathogens are active against unicellular eukaryotes. Bacterial pathogenicity might thus be one playing option of the stone-scissor-paper game played between phages-bacteria-protists, with humans getting into the crossfire.

  20. Selection of staphylococcal enterotoxin B (SEB)-binding peptide using phage display technology

    International Nuclear Information System (INIS)

    Soykut, Esra Acar; Dudak, Fahriye Ceyda; Boyaci, Ismail Hakki

    2008-01-01

    In this study, peptides were selected to recognize staphylococcal enterotoxin B (SEB) which cause food intoxication and can be used as a biological war agent. By using commercial M13 phage library, single plaque isolation of 38 phages was done and binding affinities were investigated with phage-ELISA. The specificities of the selected phage clones showing high affinity to SEB were checked by using different protein molecules which can be found in food samples. Furthermore, the affinities of three selected phage clones were determined by using surface plasmon resonance (SPR) sensors. Sequence analysis was realized for three peptides showing high binding affinity to SEB and WWRPLTPESPPA, MNLHDYHRLFWY, and QHPQINQTLYRM amino acid sequences were obtained. The peptide sequence with highest affinity to SEB was synthesized with solid phase peptide synthesis technique and thermodynamic constants of the peptide-SEB interaction were determined by using isothermal titration calorimetry (ITC) and compared with those of antibody-SEB interaction. The binding constant of the peptide was determined as 4.2 ± 0.7 x 10 5 M -1 which indicates a strong binding close to that of antibody

  1. Effectiveness of the lactococcal abortive infection systems AbiA, AbiE, AbiF and AbiG against P335 type phages.

    Science.gov (United States)

    Tangney, Mark; Fitzgerald, Gerald F

    2002-04-23

    Four lactococcal abortive infection mechanisms were introduced into strains which were sensitive hosts for P335 type phages and plaque assay experiments performed to assess their effect on five lactococcal bacteriophages from this family. Results indicate that AbiA inhibits all five P335 phages tested, while AbiG affects phiP335 itself and phiQ30 but not the other P335 species phages. AbiA was shown to retard phage Q30 DNA replication as previously reported for other phages. It was also demonstrated that AbiG, previously shown to act at a point after DNA replication in the cases of c2 type and 936 type phages, acts at the level of, or prior to phage Q30 DNA replication. AbiE and AbiF had no effect on the P335 type phages examined.

  2. Empirical complexities in the genetic foundations of lethal mutagenesis.

    Science.gov (United States)

    Bull, James J; Joyce, Paul; Gladstone, Eric; Molineux, Ian J

    2013-10-01

    From population genetics theory, elevating the mutation rate of a large population should progressively reduce average fitness. If the fitness decline is large enough, the population will go extinct in a process known as lethal mutagenesis. Lethal mutagenesis has been endorsed in the virology literature as a promising approach to viral treatment, and several in vitro studies have forced viral extinction with high doses of mutagenic drugs. Yet only one empirical study has tested the genetic models underlying lethal mutagenesis, and the theory failed on even a qualitative level. Here we provide a new level of analysis of lethal mutagenesis by developing and evaluating models specifically tailored to empirical systems that may be used to test the theory. We first quantify a bias in the estimation of a critical parameter and consider whether that bias underlies the previously observed lack of concordance between theory and experiment. We then consider a seemingly ideal protocol that avoids this bias-mutagenesis of virions-but find that it is hampered by other problems. Finally, results that reveal difficulties in the mere interpretation of mutations assayed from double-strand genomes are derived. Our analyses expose unanticipated complexities in testing the theory. Nevertheless, the previous failure of the theory to predict experimental outcomes appears to reside in evolutionary mechanisms neglected by the theory (e.g., beneficial mutations) rather than from a mismatch between the empirical setup and model assumptions. This interpretation raises the specter that naive attempts at lethal mutagenesis may augment adaptation rather than retard it.

  3. A multivariate model of stakeholder preference for lethal cat management.

    Science.gov (United States)

    Wald, Dara M; Jacobson, Susan K

    2014-01-01

    Identifying stakeholder beliefs and attitudes is critical for resolving management conflicts. Debate over outdoor cat management is often described as a conflict between two groups, environmental advocates and animal welfare advocates, but little is known about the variables predicting differences among these critical stakeholder groups. We administered a mail survey to randomly selected stakeholders representing both of these groups (n=1,596) in Florida, where contention over the management of outdoor cats has been widespread. We used a structural equation model to evaluate stakeholder intention to support non-lethal management. The cognitive hierarchy model predicted that values influenced beliefs, which predicted general and specific attitudes, which in turn, influenced behavioral intentions. We posited that specific attitudes would mediate the effect of general attitudes, beliefs, and values on management support. Model fit statistics suggested that the final model fit the data well (CFI=0.94, RMSEA=0.062). The final model explained 74% of the variance in management support, and positive attitudes toward lethal management (humaneness) had the largest direct effect on management support. Specific attitudes toward lethal management and general attitudes toward outdoor cats mediated the relationship between positive (pstakeholder intention to support non-lethal cat management. Our findings suggest that stakeholders can simultaneously perceive both positive and negative beliefs about outdoor cats, which influence attitudes toward and support for non-lethal management.

  4. Measurment of radon, thoron and their progeny in indoor environment of Mohali, Punjab, Northern India, using pinhole dosimeters

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    Mehta Vimal

    2016-01-01

    Full Text Available The health hazards of radon and its decay products above certain levels are well known. However, for any preventive measures to be taken, we have to be aware of radon levels of that particular area. Measurement of radon and its decay products in indoor environments is an important aspect of assessing indoor air quality and health conditions associated with it. Keeping this in mind, measurements of radon, thoron and their progeny concentrations were carried out in Mohali, Northern India, using pinhole-based twin cup dosimeters. Radon exhalation rates of soil samples in the dwellings/areas were measured via an active technique of a continuous radon monitor. The indoor radon concentration in Mohali varied from 15.03 ± 0.61 Bq/m3 to 39.21 ± 1.46 Bq/m3 with an average of 26.95 Bq/m3 ,while thoron concentration in the same dwellings varied from 9.62 ± 0.54 Bq/m3 to 52.84 ± 2.77 Bq/m3 with an average of 31.09 Bq/m3. Radon progeny levels in dwellings under study varied from 1.63 to 4.24 mWL, with an average of 2.94 mWL, while thoron progeny levels varied from 0.26 to 1.43 mWL , with an average of 0.84 mWL. The annual dose received by the inhabitants of dwellings under study varied from 0.78 to 2.36 mSv, with an average of 1.61 mSv. The in situ gamma dose rate varied from 0.12 to 0.32 mSv/h.

  5. Early and delayed pinhole MIBI SPECT in detecting hyperfunctioning parathyroid glands: a comparison with peroperative γ probe.

    Science.gov (United States)

    Gültekin, Salih Sinan; Kir, Metin; Tuğ, Tuğbay; Demirer, Seher; Genç, Yasemin

    2011-10-01

    This study was conducted to evaluate the early and delayed pinhole MIBI single photon emission computed tomography (pSPECT) images in detecting hyperfunctioning parathyroid glands, to make a comparison with peroperative γ probe (GP) findings. Planar, early, and delayed pSPECT scans and skin in-vivo and ex-vivo GP counts were obtained in 22 patients with hyperparathyroidism. All data were analyzed statistically on the basis of localization of the lesions, using the histopathological findings as the gold standard. Histopathological examinations revealed 18 of 44 adenomas, 18 of 44 hyperplasic glands, two of 44 lymph nodules, five of 44 thyroid nodules, and one of 44 normal parathyroid glands. Sensitivity and specificity were found to be 36 and 100% for planar, 69 and 75% for early pSPECT, 86 and 88% for delayed pSPECT scans, and similarly, 78 and 75% on skin, 92 and 75% in-vivo and 83 and 100% ex-vivo GP counts, respectively. For distinction ability of GP counts between three groups of lesions, there was a statistically significant difference among the three groups for ex-vivo GP counts but not between groups of adenomas and hyperplasic lesions for in-vivo GP counts. Early and delayed pSPECT scans play a complementary role on the planar scans. Delayed pSPECT scans and in-vivo GP counts are equally valuable to localize both single and multiple hyperfunctioning parathyroid glands. Ex-vivo GP counts seem to be better for making a distinction among types of lesions.

  6. An Unusual Phage Repressor Encoded by Mycobacteriophage BPs.

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    Valerie M Villanueva

    Full Text Available Temperate bacteriophages express transcription repressors that maintain lysogeny by down-regulating lytic promoters and confer superinfection immunity. Repressor regulation is critical to the outcome of infection-lysogenic or lytic growth-as well as prophage induction into lytic replication. Mycobacteriophage BPs and its relatives use an unusual integration-dependent immunity system in which the phage attachment site (attP is located within the repressor gene (33 such that site-specific integration leads to synthesis of a prophage-encoded product (gp33103 that is 33 residues shorter at its C-terminus than the virally-encoded protein (gp33136. However, the shorter form of the repressor (gp33103 is stable and active in repression of the early lytic promoter PR, whereas the longer virally-encoded form (gp33136 is inactive due to targeted degradation via a C-terminal ssrA-like tag. We show here that both forms of the repressor bind similarly to the 33-34 intergenic regulatory region, and that BPs gp33103 is a tetramer in solution. The BPs gp33103 repressor binds to five regulatory regions spanning the BPs genome, and regulates four promoters including the early lytic promoter, PR. BPs gp33103 has a complex pattern of DNA recognition in which a full operator binding site contains two half sites separated by a variable spacer, and BPs gp33103 induces a DNA bend at the full operator site but not a half site. The operator site structure is unusual in that one half site corresponds to a 12 bp palindrome identified previously, but the other half site is a highly variable variant of the palindrome.

  7. Biology of the temperate Streptococcus thermophilus bacteriophage TP-J34 and physical characterization of the phage genome

    International Nuclear Information System (INIS)

    Neve, Horst; Freudenberg, Wiebke; Diestel-Feddersen, Frederike; Ehlert, Regina; Heller, Knut J.

    2003-01-01

    The temperate Streptococcus thermophilus bacteriophage TP-J34 was identified in the lysogenic host strain J34. The majority of phage particles produced upon induction was defective and noninfectious, consisting of DNA-filled heads lacking tails. A physical map (45.6 kb) was established. Analysis of minor restriction bands of the DNA isolated from phage particles as well as the analysis of the protein pattern indicated that phage TP-J34 is a pac-type phage. This was confirmed by immunoelectron microscopy using antisera raised against virulent cos- and pac-type S. thermophilus phages. The lysogenic host J34 but not its noninducible derivate J34-12 contained phage DNA in the nonintegrated state and exhibited autolysis at elevated temperatures. Prophage-carrying strains grew homogeneously while 16 of 20 prophage-cured derivatives aggregated and sedimented rapidly. When phage TP-J34 was propagated lytically on a prophage-cured host strain, a 2.7-kb site-specific deletion occurred in the phage genome. This deletion was also identified in the prophage DNAs of relysogenized strains

  8. Large palindromes in the lambda phage genome are preserved in a rec/sup +/ host by inhibiting lambda DNA replication

    Energy Technology Data Exchange (ETDEWEB)

    Shurvinton, C.E.; Stahl, M.M.; Stahl, F.W.

    1987-03-01

    A large palindrome carried by phage lambda has been shown to prevent growth of the phage on a rec/sup +/ strain of Escherichia coli. The phage do form plaques on recBC sbcB strains, but the palindrome is not stable - deletions that either destroy the palindrome or diminish its size overgrow the original engineered palindrome-containing phage. The authors have prepared stocks of lambda carrying a palindrome that is 2 x 4200 base pairs long. lambda phage were density labeled by UV induction of lysogens grown in minimal medium containing (/sup 13/C) glucose and /sup 15/NH/sub 4/Cl. These phage stocks are produced by induction of a lysogen in which the two halves of the palindrome are stored at opposite ends of the prophage and are of sufficient titer (10/sup 9/ phage per ml) to enable one-step growth experiments with replication-blocked phage. They find that the large palindrome as well as a lesser palindrome of 2 x 265 base pairs are recovered intact among particles carrying unreplicated chromosomes following such an infection of a rec/sup +/ host. they propose that DNA replication drives the extrusion of palindromic sequences in vivo, forming secondary structures that are substrates for the recBC and sbcB gene products.

  9. Impact of reducing and oxidizing agents on the infectivity of Qβ phage and the overall structure of its capsid.

    Science.gov (United States)

    Loison, Pauline; Majou, Didier; Gelhaye, Eric; Boudaud, Nicolas; Gantzer, Christophe

    2016-11-01

    phages infect Escherichia coli in the human gut by recognizing F-pili as receptors. Infection therefore occurs under reducing conditions induced by physiological agents (e.g. glutathione) or the intestinal bacterial flora. After excretion in the environment, phage particles are exposed to oxidizing conditions and sometimes disinfection. If inactivation does not occur, the phage may infect new hosts in the human gut through the oral route. During such a life cycle, we demonstrated that, outside the human gut, cysteines of the major protein capsid of Qβ phage form disulfide bonds. Disinfection with NaClO does not allow overoxidation to occur. Such oxidation induces inactivation rather by irreversible damage to the minor proteins. In the presence of glutathione, most disulfide bonds are reduced, which slightly increases the capacity of the phage to infect E. coli in vitro Such reduction is reversible and barely alters infectivity of the phage. Reduction of all disulfide bonds by dithiothreitol leads to complete capsid destabilization. These data provide new insights into how the phages are impacted by oxidizing-reducing conditions outside their host cell and raises the possibility of the intervention of the redox during life cycle of the phage. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. The use of antibiotics to improve phage detection and enumeration by the double-layer agar technique

    Directory of Open Access Journals (Sweden)

    Ferreira Eugénio C

    2009-07-01

    Full Text Available Abstract Background The Double-Layer Agar (DLA technique is extensively used in phage research to enumerate and identify phages and to isolate mutants and new phages. Many phages form large and well-defined plaques that are easily observed so that they can be enumerated when plated by the DLA technique. However, some give rise to small and turbid plaques that are very difficult to detect and count. To overcome these problems, some authors have suggested the use of dyes to improve the contrast between the plaques and the turbid host lawns. It has been reported that some antibiotics stimulate bacteria to produce phages, resulting in an increase in final titer. Thus, antibiotics might contribute to increasing plaque size in solid media. Results Antibiotics with different mechanisms of action were tested for their ability to enhance plaque morphology without suppressing phage development. Some antibiotics increased the phage plaque surface by up to 50-fold. Conclusion This work presents a modification of the DLA technique that can be used routinely in the laboratory, leading to a more accurate enumeration of phages that would be difficult or even impossible otherwise.

  11. Antibody engineering using phage display with a coiled-coil heterodimeric Fv antibody fragment.

    Directory of Open Access Journals (Sweden)

    Xinwei Wang

    Full Text Available A Fab-like antibody binding unit, ccFv, in which a pair of heterodimeric coiled-coil domains was fused to V(H and V(L for Fv stabilization, was constructed for an anti-VEGF antibody. The anti-VEGF ccFv showed the same binding affinity as scFv but significantly improved stability and phage display level. Furthermore, phage display libraries in the ccFv format were constructed for humanization and affinity maturation of the anti-VEGF antibody. A panel of V(H frameworks and V(H-CDR3 variants, with a significant improvement in affinity and expressibility in both E. coli and yeast systems, was isolated from the ccFv phage libraries. These results demonstrate the potential application of the ccFv antibody format in antibody engineering.

  12. Assessment of the Microscreen phage-induction assay for screening hazardous wastes

    Energy Technology Data Exchange (ETDEWEB)

    Houk, V.S.; DeMarini, D.M.

    1987-09-01

    The Microscreen phage-induction assay, which quantitatively measures the induction of prophage lambda in Escherichia coli WP2s(lambda), was used to test 14 crude (unfractionated) hazardous industrial waste samples for genotoxic activity in the presence and absence of metabolic activation. Eleven of the 14 wastes induced prophage, and induction was observed at concentrations as low as 0.4 picograms per ml. Comparisons between the mutagenicity of these waste samples in Salmonella and their ability to induce prophage lambda indicate that the Microscreen phage-induction assay detected genotoxic activity in all but one of the wastes that were mutagenic in Salmonella. Moreover, the Microscreen assay detected as genotoxic 5 additional wastes that were not detected in the Salmonella assay. The applicability of the Microscreen phage-induction assay for screening hazardous wastes for genotoxic activity is discussed along with some of the problems associated with screening highly toxic wastes containing toxic volatile compounds.

  13. Tetracycline consumption and occurrence of tetracycline resistance in Salmonella typhimurium phage types from Danish pigs

    DEFF Research Database (Denmark)

    Emborg, Hanne-Dorthe; Vigre, Håkan; Jensen, Vibeke Frøkjær

    2007-01-01

    more than doubled at the national level from 12,000-13,000 kg of active compound in 1996-1998 to 29,000 kg of active compound in 2004. Instead, tetracycline-resistant S. Typhimurium phage types became more prevalent. This suggests that the spread of already established or new resistant clones, rather......The aims of the present study were to investigate at the farm-owner level the effect of prescribed tetracycline consumption in pigs and different Salmonella Typhimurium phage types on the probability that the S. Typhimurium was resistant to tetracycline. In this study, 1,307 isolates were included......, originating from 877 farm owners, and data were analyzed using logistic regression. The analysis showed that both the S. Typhimurium phage type (p type...

  14. The factors affecting effectiveness of treatment in phages therapy, mini review

    Directory of Open Access Journals (Sweden)

    Mai Huong eCHATAIN-LY

    2014-02-01

    Full Text Available In recent years, the use of lytic bacteriophages as antimicrobial agents controlling pathogenic bacteria has appeared as a promising new alternative strategy in the face of growing antibiotic resistance which has caused problems in many fields including medicine, veterinary medicine and aquaculture. The use of bacteriophages has numerous advantages over traditional antimicrobials. The effectiveness of phage applications in fighting against pathogenic bacteria depends on several factors such as the bacteriophages/target bacteria ratio, the mode and moment of treatment, environmental conditions (pH, temperature ..., the neutralization of phage and accessibility to target bacteria, amongst others. This report presents these factors and the challenges involved in developing phage therapy applications

  15. Ménage à trois in the human gut: interactions between host, bacteria and phages.

    Science.gov (United States)

    Mirzaei, Mohammadali Khan; Maurice, Corinne F

    2017-07-01

    The human gut is host to one of the densest microbial communities known, the gut microbiota, which contains bacteria, archaea, viruses, fungi and other microbial eukaryotes. Bacteriophages in the gut are largely unexplored, despite their potential to regulate bacterial communities and thus human health. In addition to helping us understand gut homeostasis, applying an ecological perspective to the study of bacterial and phage communities in the gut will help us to understand how this microbial system functions. For example, temporal studies of bacteria, phages and host immune cells in the gut during health and disease could provide key information about disease development and inform therapeutic treatments, whereas understanding the regulation of the replication cycles of phages could help harness the gut microbiota to improve disease outcomes. As the most abundant biological entities in our gut, we must consider bacteriophages in our pursuit of personalized medicine.

  16. The Lytic SA Phage Demonstrate Bactericidal Activity against Mastitis Causing Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Hamza Ameer

    2016-01-01

    Full Text Available Staphylococcus aureus is the major causative agent of mastitis among dairy animals as it causes intramammary gland infection. Due to antibiotic resistance and contamination of antibiotics in the milk of diseased animals; alternative therapeutic agents are required to cure mastitis. Lytic bacteriophages and their gene products can be potential therapeutic agents against bacteria as they are host specific and less harmful than antibiotics. In this study, Staphylococcus aureus were isolated from milk samples of the infected animals and identified biochemically. SA phage was isolated from sewage water showing lytic activity against Staphylococcus aureus isolates. The highest lytic activity of bacteriophages was observed at 37°C and pH 7, and the most suitable storage condition was at 4°C. SA phage efficiently reduced bacterial growth in the bacterial reduction assay. The characterization and bacterial growth reduction activity of the bacteriophages against Staphylococcus aureus signifies their underlying potential of phage therapy against mastitis.

  17. Use of a Regression Model to Study Host-Genomic Determinants of Phage Susceptibility in MRSA

    DEFF Research Database (Denmark)

    Zschach, Henrike; Larsen, Mette V; Hasman, Henrik

    2018-01-01

    strains to 12 (nine monovalent) different therapeutic phage preparations and subsequently employed linear regression models to estimate the influence of individual host gene families on resistance to phages. Specifically, we used a two-step regression model setup with a preselection step based on gene...... family enrichment. We show that our models are robust and capture the data's underlying signal by comparing their performance to that of models build on randomized data. In doing so, we have identified 167 gene families that govern phage resistance in our strain set and performed functional analysis...... on them. This revealed genes of possible prophage or mobile genetic element origin, along with genes involved in restriction-modification and transcription regulators, though the majority were genes of unknown function. This study is a step in the direction of understanding the intricate host...

  18. Study of the phage production efficiency in the bacteria lysis processes

    International Nuclear Information System (INIS)

    Vidania Munoz, R. de; Garces, F.; Davila, C. A.

    1979-01-01

    In this work we present a search for the best production conditions of λvir andλ clear phages In E coli K12 and E coli C 6 00 infected cells respectively. By keeping fixed some parameters of the process as the bacterial and phage generation times and (he bacterial burst side, we have finder that the lysis yield is strongly dependent on the multiplicity and in a lesser degree on the infection time. It appears from the experimental results that other variables are important, as infection efficiency and approach time from phages to bacteria. We will try to describe the lysis phenomenon by a numerical model on the bases of the se experimental results. (Author) 11 refs

  19. Effects of lethal and non-lethal malaria on the mononuclear phagocyte system

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Tosta

    1983-03-01

    Full Text Available The effects ofone non-lethal species ofmalarialparasite, Plasmodium yoelii, and one lethal species, P. berghei, on the mononuclear phagocyte system (MPS of BALB/c mice were studied. P. yoelii caused a greater and more sustained expansion and activation of the MPS, and the two major populations of spleen phagocytic cells-red pulp and marginal zone macrophages - exhibited a greater increase in numbers in this infection. During the course of P. berghei mataria, the spleen was progressively occupied by haematopoietic tissue and, at the terminal stage of infection, an extensive depletion of lymphocytes and macrophages was apparent. The possibility was suggested that the outcome of mataria may be inftuenced by the particular way the parasite interacts with the MPS.Estudou-se o efeito da infecção causada por espécie letal (Plasmodium berghei e não- letal (P. yoelii de plasmódio sobre o sistema de fagócitos mononucleares de camundongo BALB/c. O P. yoelii causou maior e mais prolongada expansão e ativação do sistema de macrófagos. As duas mais importantes populações de fagócitos esplênicos - macrófagos de polpa vermelha e da zona marginal - exibiam maior aumento do número de células nesta infecção. Durante a evolução da malária por P. berghei, o baço foi progressivamente ocupado por tecido hematopoiético e, na fase terminal da infecção, observou-se significativa depleção dos linfócitos e macrófagos esplênicos. Os dados apresentados indicam que a evolução da malária depende do tipo de interação entre o plasmódio e o sistema de fagócitos mononucleares.

  20. Analysis of time of death of prenatally lethal Steeloid mutations

    International Nuclear Information System (INIS)

    Rinchik, E.M.; Cummings, C.C.; Bangham, J.W.; Hunsicker, P.R.; Phipps, E.L.; Stelzner, K.F.

    1987-01-01

    Deletion mutations have been extremely useful in initiating the functional and molecular dissections of regions of the mouse genome. For the d-se and c regions, for example, it was observed that radiation mutations carrying lethal factors separable, by complementation analysis, from the primary d, se, or c mutation itself, could often be associated at both the genetic and molecular levels with multilocus chromosomal deletions. Since many of the Oak Ridge Sld mutations arose in radiation mutagenesis experiments, a substantial number may carry chromosomal deletions that involve the Sl locus in chromosome 10. Because of the great value of deletion mutations for the genetic and molecular analysis of chromosomal regions and complex genetic loci, they have initiated a series of experiments designed to test whether radiation-induced Sld mutations carry other lethal factors, in addition to the lethality caused by severe alleles of the Sl locus itself, as one prescreen for identifying Sld's that are caused by deletions